Life Extension Magazine®

Issue: May 2011

Hypertension

Endogenous sex hormones and endometrial cancer risk in women in the European Prospective Investigation into Cancer and Nutrition (EPIC).

Epidemiological data show that reproductive and hormonal factors are involved in the etiology of endometrial cancer, but there is little data on the association with endogenous sex hormone levels. We analyzed the association between prediagnostic serum concentrations of sex steroids and endometrial cancer risk in the European Prospective Investigation into Cancer and Nutrition using a nested case-control design of 247 incident endometrial cancer cases and 481 controls, matched on center, menopausal status, age, variables relating to blood collection, and, for premenopausal women, phase of menstrual cycle. Using conditional regression analysis, endometrial cancer risk among postmenopausal women was positively associated with increasing levels of total testosterone, free testosterone, estrone, total estradiol, and free estradiol. The odds ratios (ORs) for the highest versus lowest tertile were 2.66 (95% confidence interval (CI) 1.50-4.72; P=0.002 for a continuous linear trend) for estrone, 2.07 (95% CI 1.20-3.60; P=0.001) for estradiol, and 1.66 (95% CI 0.98-2.82; P=0.001) for free estradiol. For total and free testosterone, ORs for the highest versus lowest tertile were 1.44 (95% CI 0.88-2.36; P=0.05) and 2.05 (95% CI 1.23-3.42; P=0.005) respectively. Androstenedione and dehydroepiandrosterone sulfate were not associated with risk. Sex hormone-binding globulin was significantly inversely associated with risk (OR for the highest versus lowest tertile was 0.57, 95% CI 0.34-0.95; P=0.004). In premenopausal women, serum sex hormone concentrations were not clearly associated with endometrial cancer risk, but numbers were too small to draw firm conclusions. In conclusion, relatively high blood concentrations of estrogens and free testosterone are associated with an increased endometrial cancer risk in postmenopausal women.

Endocr Relat Cancer. 2008 Jun;15(2):485-97

Sex hormone binding globulin: origin, function and clinical significance.

Sex hormone binding globulin (SHBG) is a glycoprotein possessing high affinity binding for 17 beta-hydroxysteriod hormones such as testosterone and oestradiol. It is probably synthesized in the liver, plasma concentrations being regulated by, amongst other things, androgen/oestrogen balance, thyroid hormones, insulin and dietary factors, it is involved in transport of sex steroids in plasma and its concentration is a major factor regulating their distribution between the protein-bound and free states. Its detailed role in the delivery of hormones to target tissues is not yet clear. Plasma SHBG concentrations are affected by a number of different diseases, high values being found in hyperthyroidism, hypogonadism, androgen insensitivity and hepatic cirrhosis in men. Low concentrations are found in myxoedema, hyperprolactinaemia and syndromes of excessive androgen activity. Concentrations are also affected by drugs such as androgens, oestrogens, thyroid hormones and anti-convulsants. Measurement of SHBG is useful in the evaluation of mild disorders of androgen metabolism and enables identification of those women with hirsutism who are more likely to respond to oestrogen therapy. Testosterone: SHBG ratios correlate well with both measured and calculated values of free testosterone and help to discriminate subjects with excessive androgen activity from normal individuals.

Ann Clin Biochem. 1990 Nov;27 ( Pt 6):532-41

Human sex hormone-binding globulin gene expression- multiple promoters and complex alternative splicing.

BACKGROUND: Human sex hormone-binding globulin (SHBG) regulates free sex steroid concentrations in plasma and modulates rapid, membrane based steroid signaling. SHBG is encoded by an eight exon-long transcript whose expression is regulated by a downstream promoter (P(L)). The SHBG gene was previously shown to express a second major transcript of unknown function, derived from an upstream promoter (P(T)), and two minor transcripts. RESULTS: We report that transcriptional expression of the human SHBG gene is far more complex than previously described. P(L) and P(T) direct the expression of at least six independent transcripts each, resulting from alternative splicing of exons 4, 5, 6, and/or 7. We mapped two transcriptional start sites downstream of P(L) and P(T), and present evidence for a third SHBG gene promoter (P(N)) within the neighboring FXR2 gene; PN regulates the expression of at least seven independent SHBG gene transcripts, each possessing a novel, 164-nt first exon (1N). Transcriptional expression patterns were generated for human prostate, breast, testis, liver, and brain, and the LNCaP, MCF-7, and HepG2 cell lines. Each expresses the SHBG transcript, albeit in varying abundance. Alternative splicing was more pronounced in the cancer cell lines. P(L)- P(T)- and P(N)-derived transcripts were most abundant in liver, testis, and prostate, respectively. Initial findings reveal the existence of a smaller immunoreactive SHBG species in LNCaP, MCF-7, and HepG2 cells. CONCLUSION: These results extend our understanding of human SHBG gene transcription, and raise new and important questions regarding the role of novel alternatively spliced transcripts, their function in hormonally responsive tissues including the breast and prostate, and the role that aberrant SHBG gene expression may play in cancer.

BMC Mol Biol. 2009 May 5;10:37

Sex hormone binding globulin and aging.

New and more active concepts of steroid binding globulin action are emerging from recent research. As a result, examination of steroid levels in aging humans and the role of steroid binding globulins need to be re-visited. This review will discuss the possibility that sex hormone binding globulin (SHBG) plays an active role in the aging process. It will discuss the changes in blood levels of SHBG in aging humans in association with sexual activity, prostate hypertrophy and cancer, uterine leiomyoma, breast cancer, obesity and particularly the relationship between SHBG and HDL-cholesterol, Alzheimer’s disease, osteoporosis, and cardiovascular disease. Starting with the idea that SHBG is an active participant in steroid action demands a re-evaluation of data demonstrating a primary change in blood SHBG levels in association with various pathologies. Here we discuss the postulate that SHBG may act at its own receptor at the plasma membrane level to influence other receptors such as scavenger receptors and HDL-cholesterol receptors. We will also suggest that SHBG is a critical marker for mating and thus may be an important physiological molecule in control of aging.

Horm Metab Res. 2009 Mar;41(3):173-82

Synthesis and regulation of sex hormone-binding globulin in obesity.

Sex hormone-binding globulin (SHBG) is a plasma glycoprotein with high binding affinity for testosterone and dihydrotestosterone and lower affinity for estradiol. SHBG is synthesized in the liver, and its plasma level is important in the regulation of plasma free and albumin-bound androgens and estrogens. Obesity and particularly excess visceral fat, known risk factors for cardiovascular and metabolic diseases, are associated with decreased testosterone levels in males and SHBG levels in both sexes. SHBG is usually positively correlated with high-density lipoprotein cholesterol and negatively correlated with triglyceride and insulin concentrations. A positive association between SHBG and various measures of insulin sensitivity has been demonstrated in both sexes, suggesting that decreased SHBG levels may be one of the components of the metabolic syndrome. We have examined pituitary-adrenocortical function, glucose tolerance, and lipoprotein and hormone levels in a large cohort of Finnish males. Abdominal obesity appears to be associated with slight hypocortisolemia and increased sensitivity to exogenous adrenocorticotropin stimulation, which may contribute to the hyperinsulinemia and related metabolic changes including decreased SHBG levels in males.

Int J Obes Relat Metab Disord. 2000 Jun;24 Suppl 2:S64-70

Non-sex hormone-binding globulin-bound testosterone as a marker for hyperandrogenism.

Recent evidence suggests that the biologically active testosterone includes both the free and albumin-bound fractions, while the sex hormone-binding globulin (SHBG)-bound steroid dissociates less readily. To examine the significance of the non-SHBG-bound testosterone (i.e. free plus albumin bound) in hyperandrogenism, we obtained single blood samples from 17 normal women, 20 regularly menstruating but hirsute women, and 20 oligoamenorrheic hirsute women. Each serum sample was analyzed for total testosterone by RIA, SHBG-binding capacity was determined by protein precipitation with 50% saturated (NH4)2SO4, and albumin was measured by colorimetry. Non-SHBG-bound and free testosterone and the testosterone to SHBG molar ratio were then calculated. Non-SHBG-bound testosterone was also assayed using differential protein precipitation. There were significant differences among the groups in the mean values of all variables (all P less than 0.05) except albumin. Measurement and calculation of serum non-SHBG-bound testosterone produced similar results, suggesting that the binding equation is valid. There was considerable overlap between normal (control mean +/- 2 SD) and abnormal subjects in all variables except non-SHBG-bound testosterone, for which only 3 regularly menstruating and 2 oligoamenorrheic hirsute subjects were in the normal range. As total testosterone levels increased, there was a significant increase in the ratio of non-SHBG-bound testosterone to free testosterone. These data suggest that albumin becomes increasingly more important in testosterone binding as the total serum testosterone level increases and that non-SHBG-bound testosterone may be the optimal marker to identify hyperandrogenism in hirsute women

J Clin Endocrinol Metab. 1985 Nov;61(5):873-6

Decreased bioavailable testosterone in aging normal and impotent men.

Tissue available (bioavailable) testosterone (T) includes circulating free T (FT) and albumin-bound T. A reasonable assessment of bioavailable T can be made by using 50% ammonium sulfate to precipitate sex hormone-binding globulin (SHBG)-bound T. The supernatant non-SHBG-bound T (non-SHBG-T) correlates well with physiological androgen activity. To assess bioavailable T in normal aging men, we analyzed serum samples from seven healthy aged men (65-83 yr old) and compared the results to samples from 13 young men (22-39 yr old). Mean serum T, FT, and LH concentrations were not significantly different in the 2 groups. However, the mean absolute non-SHBG-T level was significantly lower (P less than 0.005) in the older group. In a separate population of 20 impotent but otherwise healthy men (5 27-37 yr old, 10 48-64 yr old, and 5 66-69 yr old), the mean absolute non-SHBG-T concentration was lower in middle-aged (P less than .01) and elderly men (P less than 0.001) than in young men. The absolute FT was lower only in the elderly group (P less than 0.05), while mean LH and T levels were similar in all 3 age groups. These data suggest that serum concentrations of tissue available T are decreased in aged men and that non-SHBG-T measurement is a more sensitive indicator of this decrease than are serum T or serum FT measurements. These changes appear to begin by middle age.

J Clin Endocrinol Metab. 1986 Dec;63(6):1418-20

Glucose tolerance and plasma testosterone concentrations in men. Results of the Asturias Study.

BACKGROUND AND OBJECTIVE: Studies in men have demonstrated a correlation between serum concentrations of androgens and sex hormone binding globulin (SHBG) with the presence of impaired glucose tolerance, diabetes and metabolic syndrome. The aim of this study was to evaluate circulating levels of total testosterone, SHBG, and bioavailable testosterone in the cohort of the Asturias Study and their association with the degree of glucose tolerance and metabolic syndrome. PATIENTS AND METHODS: The study population consisted of 282 men aged 36 to 85 years old with normal concentrations of total testosterone. The degree of glucose tolerance and the presence of metabolic syndrome were evaluated. RESULTS: Serum concentrations of testosterone and bioavailable testosterone were negatively correlated with age, body mass index, waist circumference, blood glucose, glycated hemoglobin levels and insulin. Serum concentrations of total testosterone, bioavailable testosterone and SHBG were lower in men with glucose intolerance or diabetes than in those with normal glucose tolerance. After multivariate analysis, age and total testosterone levels were independent predictors of the presence of diabetes or glucose intolerance. The risk of glucose intolerance or diabetes mellitus was over 2.5 times higher in men with total testosterone levels in the lowest quartile than in those with total testosterone in the top quartile.CONCLUSIONS: In this general population sample from Asturias, men with lower plasma concentrations of total testosterone—even when within the normal range—have an increased risk of glucose intolerance or diabetes, regardless of age and body mass index.

Endocrinol Nutr. 2011 Jan;58(1):3-8

Associations of endogenous testosterone and SHBG with glycated haemoglobin in middle-aged and older men.

Low circulating levels of testosterone and sex hormone-binding Objective: globulin (SHBG) are associated with increased cardiovascular risk in men. This association may be partially mediated through changes in glucose metabolism, but relatively few data are available on the relationship between sex hormones and markers of long-term glycaemia. We assessed the associations of endogenous testosterone and SHBG with glycated haemoglobin (HbA(1c)) in men. Design and Crosssectional study of 1,292 men from the Norfolk population of subjects: European Prospective Investigation into Cancer (EPIC-Norfolk). Measurements: HbA(1c) , total testosterone (TT) and SHBG levels were measured and free testosterone (FT) levels were calculated. Multiple linear regression models were Men used to assess the associations of TT, SHBG and FT with HbA(1c). Results: with self-reported diabetes or undiagnosed diabetes had lower testosterone and SHBG levels. In non-diabetic men, HbA(1c) levels were inversely associated with TT and calculated FT independently of age, body mass index, smoking, alcohol consumption and physical activity. The adjusted change in HbA(1c) was 0.055 (95% CI 0.025; 0.085) per standard deviation (sd) decrease in TT and 0.041 (95% CI 0.010; 0.073) per sd decrease in calculated FT respectively. SHBG levels were inversely associated with HbA(1c) after multivariable adjustment (beta = 0.038 In middle-aged and older per sd decrease (95% CI 0.004; 0.071)). Conclusions: men, low endogenous testosterone and SHBG levels are associated with glycaemia, even below the threshold for diabetes. Further studies are needed to determine the effects of interventions that raise testosterone levels in men having increased HbA(1c) and subnormal testosterone levels.

Clin Endocrinol (Oxf). 2010 Dec 15

Lower sex hormone-binding globulin is more strongly associated with metabolic syndrome than lower total testosterone in older men: the Health in Men Study.

BACKGROUND: Reduced circulating testosterone and sex hormone-binding globulin (SHBG) are implicated as risk factors for metabolic syndrome. As SHBG increases with age while testosterone declines, we examined the relative contributions of SHBG and testosterone to the risk of metabolic syndrome in older men. METHODS: We conducted a cross-sectional study of 2,502 community-dwelling men aged > or = 70 years without known diabetes. Metabolic syndrome was defined using the National Cholesterol Education Program-Third Adult Treatment Panel (NCEP-ATPIII) criteria. Early morning fasting sera were assayed for total testosterone, SHBG and LH. Free testosterone was calculated using mass action equations. RESULTS: There were 602 men with metabolic syndrome (24.1%). The risk of metabolic syndrome increased for total testosterone < 20 nmol/l, SHBG < 50 nmol/l and free testosterone < 300 pmol/l. In univariate analyses SHBG was associated with all five components of metabolic syndrome, total testosterone was associated with all except hypertension, and free testosterone was associated only with waist circumference and triglycerides. In multivariate analysis, both total testosterone and especially SHBG remained associated with metabolic syndrome, with odds ratios of 1.34 (95% confidence interval (CI): 1.18-1.52) and 1.77 (95% CI: 1.53-2.06) respectively. Men with hypogonadotrophic hypogonadism (total testosterone < 8 nmol/l, LH < or = 12 IU/l) had the highest prevalence of metabolic syndrome (53%, P<0.001). CONCLUSIONS: Lower SHBG is more strongly associated with metabolic syndrome than lower total testosterone in community-dwelling older men. SHBG may be the primary driver of these relationships, possibly reflecting its relationship with insulin sensitivity. Further studies should examine whether measures that raise SHBG protect against the development of metabolic syndrome in older men.

Eur J Endocrinol. 2008 Jun;158(6):785-92

SHBG, Sex Hormones, and Inflammatory Markers in Older Women.

Context: In premenopausal and older women, high testosterone and estradiol (E2) and low SHBG levels are associated with insulin resistance and diabetes, conditions characterized by low-grade inflammation. Objective: The aim of the study was to examine the relationship between SHBG, total testosterone, total E2, and inflammatory markers in older women. Design and Patients: We conducted a retrospective cross-sectional study of 433 women at least 65 yr old from the InCHIANTI Study, Italy, who were not on hormone replacement therapy or recently hospitalized and who had complete data on SHBG, testosterone, E2, C-reactive protein (CRP), IL-6, soluble IL-6 receptor (sIL-6r), and TNF-. Relationships between sex hormones and inflammatory markers were examined by multivariate linear regression analyses adjusted for age, body mass index, smoking, insulin, physical activity, and chronic disease. Results: In fully adjusted analyses, SHBG was negatively associated with CRP (P = 0.007), IL-6 (P = 0.008), and sIL-6r (P = 0.02). In addition, testosterone was positively associated with CRP (P = 0.006), IL-6 (P = 0.001), and TNF- (P = 0.0002). The negative relationship between testosterone and sIL-6r in an age-adjusted model (P = 0.02) was no longer significant in a fully adjusted model (P = 0.12). E2 was positively associated with CRP (P = 0.002) but not with IL-6 in fully adjusted models. In a final model including E2, testosterone, and SHBG, and all the confounders previously considered, SHBG (0.23 ± 0.08; P = 0.006) and E2 (0.21 ± 0.08; P = 0.007), but not testosterone (P = 0.21), were still significantly associated with CRP. Conclusion: In late postmenopausal women not on hormone replacement therapy, SHBG and E2 are, respectively, negative and positive, independent and significant correlates of a proinflammatory state.

J Clin Endocrinol Metab. 2011 Jan 14

The role of NK cells in antitumor activity of dietary fucoidan from Undaria pinnatifida sporophylls (Mekabu).

Fucoidan from Mekabu (sporophyll of Undaria pinnatifida), a dietary alga, exerts antitumor activity possibly through enhancing the immune response. The present report describes the effects of dietary Mekabu fucoidan on the tumor growth of mouse A20 leukemia cells and on T cell-mediated immune responses in T cell receptor transgenic (DO-11 - 10 - Tg) mice. The animals were fed with a diet containing 1% Mekabu fucoidan (0.034 +/- 0.003 g/mouse/day) for 10 days and subcutaneously (s. c.) inoculated with A20 leukemia cells. Thereafter, the mice were fed with the diet containing fucoidan for 40 days. Mekabu fucoidan inhibited tumors by 65.4 %. We studied how the killer activities of T cell-mediated and natural killer (NK) cells are augmented in DO-11 - 10 mice fed with Mekabu fucoidan. The cytolytic activities of ovalbumin (OVA), which is specific against OVA-transfected A20 (OVA-A20) B lymphoma cells, and NK cells against YAC-1 were significantly enhanced in the mice fed with fucoidan compared with a basic diet. Thus, these findings suggested that Mekabu fucoidan mediates tumor destruction through Th1 cell and NK cell responses.

Planta Med. 2006 Dec;72(15):1415-7

Low molecular weight fucoidan prevents neointimal hyperplasia after aortic allografting.

BACKGROUND: Fucoidan, a new low molecular weight sulfated polysaccharide (LMWF), has previously been shown to mobilize bone marrow-derived progenitors cells via stimulation of stromal derived factor (SDF)-1 release. Mobilized progenitor cells have been suggested to repair intimal lesions after immune-mediated endothelial injury and thus prevent intimal proliferation. The aim of this study was to evaluate the effect of LMWF treatment in a rat aortic allograft model of transplant arteriosclerosis (TA). METHODS: Aortic grafts were performed in Brown Norway (BN, donor) and Lewis (Lew, recipient) rats. The recipient rats were treated with LMWF (5 mg/kg/day) and sacrificed at 30 days. To determine the role of SDF-1 in mediating the effects of LMWF, a specific inhibitor of the SDF-1 receptor CXCR4, AMD 3100 (20 microg/kg/day), was used. The grafted segments were evaluated by morphometric (histochemical) analyses. RESULTS: Untreated aortic allografts exhibited severe intimal proliferation, indicative of TA. In contrast, LMWF treatment significantly prevented allograft intimal proliferation as compared with controls (5.7+/-3 vs. 66.2+/-6 microm, P<0.01) and permitted a normalization of the intima/media ratio (0.1+/-0.1 vs. 1.7+/-0.3, P<0.01). Further, LMWF treatment stimulated allograft reendothelialization, as evidenced by strong intimal endothelial nitric oxide synthase antibody and CD31 signals. Unexpectedly, AMD treatment failed to prevent the protective effect of LMWF on intimal thickening and AMD treatment alone was found to reduced intimal proliferation in allografts. CONCLUSIONS: We found that LMWF treatment reduced intimal thickness and induced the presence of an endothelial cell lining in the vascular graft at 30 days. Our findings may suggest a novel therapeutic strategy in the prevention of TA.

Transplantation. 2007 May 15;83(9):1234-41

Induction of hepatocyte growth factor by fucoidan and fucoidan-derived oligosaccharides.

Fucoidan, which is extracted from brown seaweed, is a complex sulphated polysaccharide that is mostly composed of L-fucose and sulphated ester groups. The structural and anionic characteristics of fucoidan are similar to those of heparin. Heparin stimulates production of hepatocyte growth factor (HGF), which has key roles in tissue regeneration. We have shown that fucoidan and fucoidan-derived oligosaccharides have similar ability to stimulate production of HGF as heparin and heparin-derived oligosaccharides. This induction of HGF by heparin or fucoidan and their oligosaccharide derivates occurs primarily at the level of translation, probably via the same mechanism. Fucoidan may thus be useful to protect tissues and organs from various injuries and diseases, via mechanisms involving HGF.

J Pharm Pharmacol. 2008 Apr;60(4):499-503

Sulfated polysaccharide fucoidan ameliorates experimental autoimmune myocarditis in rats.

Homing of cardiac myosin-specific CD4-positive T cells into the myocardium is the initial pathologic event of experimental autoimmune myocarditis (EAM). Subsequently, various bystander inflammatory cells are recruited into the myocardium crossing vascular endothelial cell walls. Sulfated polysaccharide fucoidan binds selectin nonselectively and blocks its function. Therefore, this study was designed to evaluate whether in vivo fucoidan treatment can improve EAM. A 21-day infusion of physiological saline or fucoidan was administrated intraperitoneally to the rats with sham operation (sham-saline, n = 5; sham-fucoidan, n = 6) or those with cardiac myosin injection (EAM-saline, n = 10; EAM-fucoidan, n = 10). After 3 weeks, fucoidan treatment improved left ventricular ejection fraction (79.04 ± 2.81 vs 65.94% ± 3.22%; P < .01 vs EAM-saline) with a reduced ratio of heart weight to body weight (4.016 ± 0.239 vs 4.975 ± 0.252 mg/g; P < .05 vs EAM-saline) in EAM. Furthermore, fucoidan treatment decreased serum levels of BNP (292.0 ± 53.4 vs 507.4 ± 89.2 ng/mL; P < .05 vs EAM-saline) and the myocarditis area (31.66 ± 1.53 vs 42.51% ± 3.24%; P < .01 vs EAM-saline) in EAM. These beneficial effects of fucoidan were accompanied by inhibition of both macrophage and CD4-positive T-cell infiltration into the myocardium. Fucoidan, a nonselective selectin blocker, attenuates the progression of EAM. This observation may be explained, at least in part, by blocking the extravasation of inflammatory cells into the myocardium.

J Cardiovasc Pharmacol Ther. 2011 Mar;16(1):79-86

Immunostimulating and anticoagulating activity of fucoidan from brown algae Fucus evanescens of Okhotskoe sea.

Fucoidan—nontoxic sulfated polysaccharide was isolated from brown algae Fucus evanescens in Okhotskoe Sea. Chemical analysis of the compound was performed, it was shown that fucoidan is freely soluble in water and acid solutions. Immunotropic and anticoagulating properties of the compound were evaluated in comparison with heparin. It was demonstrated that fucoidan in wide range of doses stimulated phagocytic and bactericidic activity at leucocytes of mice peritoneal exudate. Heparin on the contrary demonstrated depressive effect on these functions at high dose. It was shown that fucoidan has dose-dependent anticoagulating activity in vitro and in vivo comparable with heparin activity. The results of investigation demonstrated possibility of fucoidan application as immunomodulating and anticoagulating agent of plant origin.

Antibiot Khimioter. 2003;48(4):11-3

Immunological analysis of inhibition of lung metastases by fucoidan (GIV-A) prepared from brown seaweed Sargassum thunbergii.

The antimetastatic effect of GIV-A (fucoidan) and/or 5-FU was examined in an experimental model of lung metastases induced by Lewis lung carcinoma in mice. Injection of GIV-A i.p. after removal of the implanted primary tumor inhibited the development of lung metastases. Combination treatment with GIV-A and 5-FU inhibited significantly the lung metastases. The number of peritoneal macrophages, total cells and macrophages in the lung increased in mice treated with GIV-A. Binding of the third component of complement (C3) cleavage products (C3b) to the C3 receptor on peritoneal macrophages after i.v. injection of GIV-A was enhanced, as shown by the fluorescent antibody technique. Lung metastases were inhibited by i.v. injection of peritoneal macrophages activated with GIV-A. GIV-A depressed aniline hydroxylase and aminopyrine demethylase activities of the hepatic microsomal drug-metabolizing system in tumor-bearing mice. Moreover, the concentration of 5-FU in the tissues (lung, liver, kidney, spleen and blood) was increased significantly by coadministration of GIV-A. The picryl chloride-induced delayed type hypersensitivity (PC-DTH) response in mice was depressed after the implantation of tumor and treatment with 5-FU. GIV-A restored the suppression of PC-DTH by 5-FU, but did not increase the PC-DTH of normal mice. GIV-A not only enhanced the degree of spleen cell-mediated sheep red blood cell (SRBC) hemolysis (quantitative hemolysis of SRBC), the indexes of the spleen and thymus and the number of spleen cells, but also restored the suppressive effect of 5-FU. In the group receiving GIV-A, the percentages of splenic Thy1.2-, L3T4- and asialo GM1-positive cells were significantly increased as compared with the tumor-bearing mice treated with saline. Furthermore, the L3T4+/Lyt2+ ratio showed a tendency to increase, and the Lyt2+/Thy1.2+ ratio was decreased. These results suggest that the antitumor effect of GIV-A may be correlated with the changing pattern of the Thy1.2-, L3T4- and asialo GM1-positive cells, C3 activation, macrophage activation and depression of the hepatic microsomal drug-metabolizing system. These findings raise the possibility that GIV-A may have clinical value in the prevention of cancer metastasis.

Anticancer Res. 1995 Sep-Oct;15(5B):1937-47

Immunomodulating activity of arabinogalactan and fucoidan in vitro.

Many polysaccharides obtained from natural sources are considered to be biological response modifiers and have been shown to enhance various immune responses. Here, we investigated the immunomodulating effects of arabinogalactan (AG) and fucoidan (FU) in vitro. Mouse spleen lymphocytes became cytotoxic to tumor cells after culture with AG and FU at concentrations of 10-100 microg/mL. Also, AG and FU were mitogenic in spleen lymphocytes and peripheral macrophages. Macrophages treated with AG and FU (10-100 microg/mL) exhibited induced tumoricidal activity and increased phagocytosis, lysosomal enzyme activity, and production of nitrite, H2O2, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6. However, AG and FU had little effect on the level of IL-1beta. Thus, the tumoricidal effect of AG- and FU-activated macrophages appeared to be mainly mediated by production of free radicals (NO and H2O2) and cytokines (TNF-alpha and IL-6). These data suggest that AG and FU are activators of lymphocytes and macrophages. This property may contribute to their effectiveness in the immunoprevention of cancer.

J Med Food. 2005 Winter;8(4):446-53

Immunostimulatory effects of fucoidan on bone marrow-derived dendritic cells.

Fucoidan is a polysaccharide purified from the brown seaweed Fucus vesiculosus. Although some effects of fucoidan on immune functions have been elucidated, there have been no studies concerning the immunomodulatory effects of fucoidan on dendritic cells (DCs), which are powerful antigen-presenting cells. In this study, fucoidan increased the viability of DCs, the production of interleukin-12 and tumor necrosis factor-alpha, and the expression of major histocompatibility complex class I, class II, CD54, and CD86 molecules. Furthermore, fucoidan-treated DCs showed decreased antigen uptake and increased proliferation of allogeneic splenocytes. In a study of the transcriptional regulation effects of fucoidan, translocation of p65 molecules of nuclear factor-kappaB (NF-kappaB) from the cytosol to the nucleus was clearly observed in fucoidan-treated DCs. Taken together, the results suggest that fucoidan has immunostimulating and maturing effects on DCs, via a pathway involving at least NF-kappaB.

Immunol Lett. 2008 Jan 29;115(2):138-43

Antitumor activity and immune response of Mekabu fucoidan extracted from Sporophyll of Undaria pinnatifida.

BACKGROUND: We showed that fucoidan, extracted from dietary seaweed, could inhibit tumor growth. However, the mechanism of Mekabu (Sporophyll of Undaria pinnatifida) fucoidan antitumor activity and how it enhances the immune response remains unknown. MATERIALS AND METHODS: We examined the effect of Mekabu fucoidan in P-388 tumor-bearing mice and in T cell-mediated NK cell activity in normal mice. RESULTS: The survival of mice was prolonged when Mekabu fucoidan was administered for 4 days before tumor cell inoculation, compared with non-treated mice. Fucoidan significantly enhanced the cytolytic activity of NK cells and increased the amount of IFN-gamma produced by T cells up to about 2-fold compared with non-treated mice. CONCLUSION: The anti-tumor effect of Mekabu fucoidan appears to be mediated by IFN-gamma-activated NK cells

In Vivo. 2003 May-Jun;17(3):245-9

Novel antiviral fucoidan from sporophyll of Undaria pinnatifida (Mekabu).

Structural characterization and antiviral activities of fucoidan from sporophyll of Undaria pinnatifida (Mekabu) was examined. The fucoidan was composed of fucose and galactose with an approximately ratio of 1.0:1.1. Degree of substitution of sulfate was 0.72 and its apparent molecular weight was 9,000. Methylation analyses showed that fucoidan had various sugar linkages, and revealed that the fucoidan might have complicated structure. This fucoidan showed potent antiviral activities against herpes simplex virus type 1 (HSV-1), HSV-2, and human cytomegalovirus.

Chem Pharm Bull (Tokyo). 2004 Sep;52(9):1091-4

Defensive effects of a fucoidan from brown alga Undaria pinnatifida against herpes simplex virus infection.

Fucoidan, a sulfated polysaccharide isolated from an edible brown alga Undaria pinnatifida, was previously shown to be a potent inhibitor of the in vitro replication of herpes simplex virus type 1 (HSV-1). HSV-1 is a member of herpes viruses that cause infections ranging from trivial mucosal ulcers to life-threatening disorders in immunocompromised hosts. In the in vivo conditions, the replication of HSV-1 is controlled under the immunoresponse coordinated by both the innate and adaptive immune systems. In the present study, the effects of the fucoidan were examined on in vivo viral replication and the host’s immune defense system. Oral administration of the fucoidan protected mice from infection with HSV-1 as judged from the survival rate and lesion scores. Phagocytic activity of macrophages and B cell blastogenesis in vitro were significantly stimulated by the fucoidan, while no significant change in the release of NO(2)(-) by macrophages was observed. In in vivo studies, oral administration of the fucoidan produced the augmentation of NK activity in HSV-1-infected mice immunosuppressed by 5-fluorouracil treatment. CTL activity in HSV-1-infected mice was also enhanced by oral administration of the fucoidan. The production of neutralizing antibodies in the mice inoculated with HSV-1 was significantly promoted during the oral administration of the fucoidan for 3 weeks. These results suggested that oral intake of the fucoidan might take the protective effects through direct inhibition of viral replication and stimulation of both innate and adaptive immune defense functions.

Int Immunopharmacol. 2008 Jan;8(1):109-16

Growth-inhibitory effect of a fucoidan from brown seaweed Undaria pinnatifida on Plasmodium parasites.

The present study was undertaken to investigate the inhibitory effects of fucoidan, a sulfated polysaccharide isolated from the edible brown seaweed Undaria pinnatifida, on the growth of Plasmodium parasites. In order to assess the anti-malarial activity of fucoidan, growth inhibition activities were evaluated using cultured Plasmodium falciparum parasites in vitro and on Plasmodium berghei-infected mice in vivo. Fucoidan significantly inhibited the invasion of erythrocytes by P. falciparum merozoites, and its 50% inhibition concentration was similar to those for the chloroquine-sensitive P. falciparum 3D7 strain and the chloroquine-resistant K1 strain. Four-day suppressive testing in P. berghei-infected mice with fucoidan resulted in a 37% suppressive effect versus the control group and a delay in death associated with anemia (P < 0.05). In addition, fucoidans had no toxic effect on RAW 264.7 cells. These findings indicate that fucoidans from the Korean brown algae U. pinnatifida inhibits the invasion of Plasmodium merozoites into erythrocytes in vitro and in vivo.

Parasitol Res. 2009 Jan;104(2):245-50

Seaweed prevents breast cancer?

To investigate the chemopreventive effects of seaweed on breast cancer, we have been studying the relationship between iodine and breast cancer. We found earlier that the seaweed, wakame, showed a suppressive effect on the proliferation of DMBA (dimethylbenz(a)anthracene)-induced rat mammary tumors, possibly via apoptosis induction. In the present study, powdered mekabu was placed in distilled water, and left to stand for 24 h at 4 degrees C. The filtered supernatant was used as mekabu solution. It showed an extremely strong suppressive effect on rat mammary carcinogenesis when used in daily drinking water, without toxicity. In vitro, mekabu solution strongly induced apoptosis in 3 kinds of human breast cancer cells. These effects were stronger than those of a chemotherapeutic agent widely used to treat human breast cancer. Furthermore, no apoptosis induction was observed in normal human mammary cells. In Japan, mekabu is widely consumed as a safe, inexpensive food. Our results suggest that mekabu has potential for chemoprevention of human breast cancer.

Jpn J Cancer Res. 2001 May;92(5):483-7

Effect of daily aspirin on long-term risk of death due to cancer: analysis of individual patient data from randomised trials.

BACKGROUND: Treatment with daily aspirin for 5 years or longer reduces subsequent risk of colorectal cancer. Several lines of evidence suggest that aspirin might also reduce risk of other cancers, particularly of the gastrointestinal tract, but proof in man is lacking. We studied deaths due to cancer during and after randomised trials of daily aspirin versus control done originally for prevention of vascular events. METHODS: We used individual patient data from all randomised trials of daily aspirin versus no aspirin with mean duration of scheduled trial treatment of 4 years or longer to determine the effect of allocation to aspirin on risk of cancer death in relation to scheduled duration of trial treatment for gastrointestinal and non-gastrointestinal cancers. In three large UK trials, long-term post-trial follow-up of individual patients was obtained from death certificates and cancer registries. RESULTS: In eight eligible trials (25,570 patients, 674 cancer deaths), allocation to aspirin reduced death due to cancer (pooled odds ratio [OR] 0·79, 95% CI 0·68-0·92, p=0·003). On analysis of individual patient data, which were available from seven trials (23,535 patients, 657 cancer deaths), benefit was apparent only after 5 years’ follow-up (all cancers, hazard ratio [HR] 0·66, 0·50-0·87; gastrointestinal cancers, 0·46, 0·27-0·77; both p=0·003). The 20-year risk of cancer death (1,634 deaths in 12,659 patients in three trials) remained lower in the aspirin groups than in the control groups (all solid cancers, HR 0·80, 0·72-0·88, p<0·0001; gastrointestinal cancers, 0·65, 0·54-0·78, p<0·0001), and benefit increased (interaction p=0·01) with scheduled duration of trial treatment (≥7·5 years: all solid cancers, 0·69, 0·54-0·88, p=0·003; gastrointestinal cancers, 0·41, 0·26-0·66, p=0·0001). The latent period before an effect on deaths was about 5 years for oesophageal, pancreatic, brain, and lung cancer, but was more delayed for stomach, colorectal, and prostate cancer. For lung and oesophageal cancer, benefit was confined to adenocarcinomas, and the overall effect on 20-year risk of cancer death was greatest for adenocarcinomas (HR 0·66, 0·56-0·77, p<0·0001). Benefit was unrelated to aspirin dose (75 mg upwards), sex, or smoking, but increased with age-the absolute reduction in 20-year risk of cancer death reaching 7·08% (2·42-11·74) at age 65 years and older. INTERPRETATION: Daily aspirin reduced deaths due to several common cancers during and after the trials. Benefit increased with duration of treatment and was consistent across the different study populations. These findings have implications for guidelines on use of aspirin and for understanding of carcinogenesis and its susceptibility to drug intervention.

Lancet. 2011 Jan 1;377(9759):31-41

Long-term effect of aspirin on colorectal cancer incidence and mortality: 20-year follow-up of five randomised trials.

BACKGROUND: High-dose aspirin (≥500 mg daily) reduces long-term incidence of colorectal cancer, but adverse effects might limit its potential for long-term prevention. The long-term effectiveness of lower doses (75-300 mg daily) is unknown. We assessed the effects of aspirin on incidence and mortality due to colorectal cancer in relation to dose, duration of treatment, and site of tumour.

METHODS: We followed up four randomised trials of aspirin versus control in primary (Thrombosis Prevention Trial, British Doctors Aspirin Trial) and secondary (Swedish Aspirin Low Dose Trial, UK-TIA Aspirin Trial) prevention of vascular events and one trial of different doses of aspirin (Dutch TIA Aspirin Trial) and established the effect of aspirin on risk of colorectal cancer over 20 years during and after the trials by analysis of pooled individual patient data. RESULTS: In the four trials of aspirin versus control (mean duration of scheduled treatment 6·0 years), 391 (2·8%) of 14 033 patients had colorectal cancer during a median follow-up of 18·3 years. Allocation to aspirin reduced the 20-year risk of colon cancer (incidence hazard ratio [HR] 0·76, 0·60-0·96, p=0·02; mortality HR 0·65, 0·48-0·88, p=0·005), but not rectal cancer (0·90, 0·63-1·30, p=0·58; 0·80, 0·50-1·28, p=0·35). Where subsite data were available, aspirin reduced risk of cancer of the proximal colon (0·45, 0·28-0·74, p=0·001; 0·34, 0·18-0·66, p=0·001), but not the distal colon (1·10, 0·73-1·64, p=0·66; 1·21, 0·66-2·24, p=0·54; for incidence difference p=0·04, for mortality difference p=0·01). However, benefit increased with scheduled duration of treatment, such that allocation to aspirin of 5 years or longer reduced risk of proximal colon cancer by about 70% (0·35, 0·20-0·63; 0·24, 0·11-0·52; both p<0·0001) and also reduced risk of rectal cancer (0·58, 0·36-0·92, p=0·02; 0·47, 0·26-0·87, p=0·01). There was no increase in benefit at doses of aspirin greater than 75 mg daily, with an absolute reduction of 1·76% (0·61-2·91; p=0·001) in 20-year risk of any fatal colorectal cancer after 5-years scheduled treatment with 75-300 mg daily. However, risk of fatal colorectal cancer was higher on 30 mg versus 283 mg daily on long-term follow-up of the Dutch TIA trial (odds ratio 2·02, 0·70-6·05, p=0·15). INTERPRETATION: Aspirin taken for several years at doses of at least 75 mg daily reduced long-term incidence and mortality due to colorectal cancer. Benefit was greatest for cancers of the proximal colon, which are not otherwise prevented effectively by screening with sigmoidoscopy or colonoscopy.

Lancet. 2010 Nov 20;376(9754):1741-50

Effect of aspirin on long-term risk of colorectal cancer: consistent evidence from randomised and observational studies.

BACKGROUND: Randomised trials have shown that aspirin reduces the short-term risk of recurrent colorectal adenomas in patients with a history of adenomas or cancer, but large trials have shown no effect in primary prevention of colorectal cancer during 10 years’ follow-up. However, the delay from the early development of adenoma to presentation with cancer is at least 10 years. We aimed to assess the longer-term effect of aspirin on the incidence of cancers. METHODS: We studied the effect of aspirin in two large randomised trials with reliable post-trial follow-up for more than 20 years: the British Doctors Aspirin Trial (N=5,139, two-thirds allocated 500 mg aspirin for 5 years, a third to open control) and UK-TIA Aspirin Trial (N=2,449, two-thirds allocated 300 mg or 1,200 mg aspirin for 1-7 years, a third placebo control). We also did a systematic review of all relevant observational studies to establish whether associations were consistent with the results of the randomised trials and, if so, what could be concluded about the likely effects of dose and regularity of aspirin use, other non-steroidal anti-inflammatory drugs (NSAID), and the effect of patient characteristics. RESULTS: In the randomised trials, allocation to aspirin reduced the incidence of colorectal cancer (pooled HR 0.74, 95% CI 0.56-0.97, p=0.02 overall; 0.63, 0.47-0.85, p=0.002 if allocated aspirin for 5 years or more). However, this effect was only seen after a latency of 10 years (years 0-9: 0.92, 0.56-1.49, p=0.73; years 10-19: 0.60, 0.42-0.87, p=0.007), was dependent on duration of scheduled trial treatment and compliance, and was greatest 10-14 years after randomisation in patients who had had scheduled trial treatment of 5 years or more (0.37, 0.20-0.70, p=0.002; 0.26, 0.12-0.56, p=0.0002, if compliant). No significant effect on incidence of non-colorectal cancers was recorded (1.01, 0.88-1.16, p=0.87). In 19 case-control studies (20 815 cases) and 11 cohort studies (1 136 110 individuals), regular use of aspirin or NSAID was consistently associated with a reduced risk of colorectal cancer, especially after use for 10 years or more, with no difference between aspirin and other NSAIDs, or in relation to age, sex, race, or family history, site or aggressiveness of cancer, or any reduction in apparent effect with use for 20 years or more. However, a consistent association was only seen with use of 300 mg or more of aspirin a day, with diminished and inconsistent results for lower or less frequent doses. INTERPRETATION: Use of 300 mg or more of aspirin a day for about 5 years is effective in primary prevention of colorectal cancer in randomised controlled trials, with a latency of about 10 years, which is consistent with findings from observational studies. Long-term follow-up is required from other randomised trials to establish the effects of lower or less frequent doses of aspirin.

Lancet. 2007 May 12;369(9573):1603-13

Low-dose aspirin in the primary prevention of cancer: the Women’s Health Study: a randomized controlled trial.

CONTEXT: Basic research and observational evidence as well as results from trials of colon polyp recurrence suggest a role for aspirin in the chemoprevention of cancer. OBJECTIVE: To examine the effect of aspirin on the risk of cancer among healthy women. DESIGN, SETTING, AND PARTICIPANTS: In the Women’s Health Study, a randomized 2 x 2 factorial trial of aspirin and vitamin E conducted between September 1992 and March 2004, 39,876 US women aged at least 45 years and initially without previous history of cancer, cardiovascular disease, or other major chronic illness were randomly assigned to receive either aspirin or aspirin placebo and followed up for an average of 10.1 years. INTERVENTION: A dose of 100 mg of aspirin (n=19,934) or aspirin placebo (n=19,942) administered every other day. MAIN OUTCOME MEASURES: Confirmed newly diagnosed invasive cancer at any site, except for nonmelanoma skin cancer. Incidence of breast, colorectal, and lung cancer were secondary end points. RESULTS: No effect of aspirin was observed on total cancer (n = 2,865; relative risk [RR], 1.01; 95% confidence interval [CI], 0.94-1.08; P = .87), breast cancer (n = 1,230; RR, 0.98; 95% CI, 0.87-1.09; P = .68), colorectal cancer (n = 269; RR, 0.97; 95% CI, 0.77-1.24; P = .83), or cancer of any other site, with the exception of lung cancer for which there was a trend toward reduction in risk (n = 205; RR, 0.78; 95% CI, 0.59-1.03; P = .08). There was also no reduction in cancer mortality either overall (n = 583; RR, 0.95; 95% CI, 0.81-1.11; P = .51) or by site, except for lung cancer mortality (n = 140; RR, 0.70; 95% CI, 0.50-0.99; P = .04). No evidence of differential effects of aspirin by follow-up time or interaction with vitamin E was found. CONCLUSIONS: Results from this large-scale, long-term trial suggest that alternate day use of low-dose aspirin (100 mg) for an average 10 years of treatment does not lower risk of total, breast, colorectal, or other site-specific cancers. A protective effect on lung cancer or a benefit of higher doses of aspirin cannot be ruled out.

JAMA. 2005 Jul 6;294(1):47-55

Aspirin chemoprevention of gastrointestinal cancer in the next decade. A review of the evidence.

Together, gastrointestinal (GI) cancers now account for 25% of neoplastic deaths in the West. In Poland, GI cancer rates are likely to increase further as westernization progresses. Given that conventional cancer therapies have made only modest reductions in cancer mortality, there is a great interest in chemoprevention to prevent or slow malignant transformation from premalignant lesions. The financial pressures in the immediate future require even more stringent criteria for chemopreventive agents - they must be cheap but also safe and efficacious. In this regard, several reviews have indicated that aspirin possesses many favorable qualities for chemoprevention. Furthermore, meta-analyses indicate that aspirin may decrease cancer by approximately 30%. Several large clinical trials are underway, including AspECT (Aspirin and Esomeprazole Chemoprevention Trial) that aims not only to prevent cancer but also decrease the gastric side effects by combining aspirin with potent acid-suppressing drugs. In conclusion, whether aspirin will be the world’s first proven chemopreventive agent is currently unknown but the evidence looks hopeful.

Pol Arch Med Wewn. 2010 Oct;120(10):407-12

Aspirin, salicylates, and cancer.

Evidence from a wide range of sources suggests that individuals taking aspirin and related non-steroidal anti-inflammatory drugs have reduced risk of large bowel cancer. Work in animals supports cancer reduction with aspirin, but no long-term randomised clinical trials exist in human beings, and randomisation would be ethically unacceptable because vascular protection would have to be denied to a proportion of the participants. However, opportunistic trials of aspirin, designed to test vascular protection, provide some evidence of a reduction in cancer, but only after at least 10 years. We summarise evidence for the potential benefit of aspirin and natural salicylates in cancer prevention. Possible mechanisms of action and directions for further work are discussed, and implications for clinical practice are considered.

Lancet. 2009 Apr 11;373(9671):1301-9

Protective association of aspirin/NSAIDs and esophageal cancer: a systematic review and meta-analysis.

BACKGROUND & AIMS: Esophageal carcinomas have high fatality rates, making chemoprevention agents desirable. We performed a systematic review with meta-analysis of observational studies evaluating the association of aspirin/nonsteroidal anti-inflammatory drug (NSAID) use and esophageal cancer. METHODS: We evaluated the MEDLINE, BIOSIS, and Web of Science electronic databases (1980-2001); manually reviewed the literature; and consulted with experts. Studies were included if they: (1) evaluated exposure to NSAIDs, aspirin, or both; (2) evaluated esophageal cancer; and (3) reported relative risks or odds ratios or provided data for their calculation. Data were independently abstracted by 2 investigators. The primary and sensitivity analyses used both fixed and random-effects models. RESULTS: Nine studies (2 cohort, 7 case control) containing 1,813 cancer cases were identified. All primary summary estimates were homogeneous. Statistical pooling showed a protective association between any use of aspirin/NSAID and esophageal cancer (odds ratio [OR] = 0.57; 95% confidence interval [CI], 0.47-0.71). Both intermittent (OR = 0.82; CI, 0.67-0.99) and frequent medication use were protective (OR = 0.54; CI, 0.43-0.67), with greater protection with more frequent use. Stratified by medication type, aspirin use was protective (OR = 0.5; CI, 0.38-0.66), and NSAIDs had a borderline protective association (OR = 0.75; CI, 0.54-1.0). Any use was protective against both esophageal adenocarcinoma (OR = 0.67; CI, 0.51-0.87) and squamous cell carcinoma (OR = 0.58; CI, 0.43-0.78). CONCLUSIONS: Pooled results support a protective association between aspirin and NSAIDs and esophageal cancer (of both histological types) and provide evidence for a dose effect. These findings support evaluating these agents in clinical trials of high-risk patients.

Gastroenterology. 2003 Jan;124(1):47-56

Aspirin and cancer risk: a summary review to 2007.

Aspirin has been associated with a reduced risk of colorectal cancer and—based on limited evidence—to cancers of the oesophagus, stomach, breast, ovary and lung. The role of aspirin on other cancers, such as pancreatic, prostate and bladder cancer and non-Hodgkin’s lymphomas and myeloma is less clear, and an increase of risk has been suggested for kidney cancer. For most cancer sites, however, significant heterogeneity between studies, and particularly between study design, was found, with a reduction in risk generally stronger in case-control studies than in cohort ones.

Recent Results Cancer Res. 2009;181:231-51

Long-term aspirin use and the risk of total, high-grade, regionally advanced and lethal prostate cancer in a prospective cohort of health professionals, 1988-2006.

Experimental studies suggest a role for aspirin in the chemoprevention of prostate cancer and epidemiological evidence supports a modest inverse association between regular aspirin use and prostate cancer risk, especially for advanced disease. In a prospective cohort study of 51,529 health professionals aged 40-75 years at baseline, we evaluated long-term aspirin use and the incidence of total, high-grade (Gleason 8-10, n=488), regionally advanced (T3b-T4 or N1, n=228) and lethal prostate cancer (M1, bony metastases or prostate cancer death, n=580) from 1988-2006. We used Cox proportional hazards regression to evaluate risk associated with frequency (days/week), quantity (tablets/week), recency and duration of aspirin use after multivariable adjustment for confounders and other predictors of prostate cancer risk. A total of 4,858 men were diagnosed with prostate cancer during the 18-year study period. Men taking ≥ 2 adult-strength aspirin tablets a week had a 10% lower risk of prostate cancer (p-for-trend=0.02). For regionally advanced cancer, we observed no significant associations with aspirin use. For high-grade and lethal disease, men taking ≥ 6 adult-strength tablets/week experienced similar reductions in risk (HR=0.72 (95% CI: 0.54, 0.96) and HR=0.71 (95% CI: 0.50, 1.00)). Analytical approaches to address bias from more frequent PSA screening among aspirin users did not yield different conclusions. We observed reductions in the risk of high-grade and lethal prostate cancer associated with higher doses of aspirin, but not with greater frequency or duration, in a large, prospective cohort of health professionals. Our data support earlier observations of modest inverse associations with advanced prostate cancer.

Int J Cancer. 2010 Dec 2

Use of aspirin and other nonsteroidal antiinflammatory medications in relation to prostate cancer risk.

Recent interest has focused on the role that inflammation may play in the development of prostate cancer and whether use of aspirin or other nonsteroidal antiinflammatory drugs (NSAIDs) affects risk. In a population-based case-control study designed to investigate the relation between these medications and prostate cancer risk, detailed exposure data were analyzed from 1,001 cases diagnosed with prostate cancer between January 1, 2002, and December 31, 2005, and 942 age-matched controls from King County, Washington. A significant 21% reduction in the risk of prostate cancer was observed among current users of aspirin compared with nonusers (95% confidence interval (CI): 0.65, 0.96). Long-term use of aspirin (>5 years: odds ratio = 0.76, 95% CI: 0.61, 0.96) and daily use of low-dose aspirin (odds ratio = 0.71, 95% CI: 0.56, 0.90) were also associated with decreased risk. There was no evidence that the association with aspirin use varied by disease aggressiveness, but there was effect modification (P(interaction) = 0.02) with a genetic variant in prostaglandin-endoperoxide synthase 2 (PTGS2) (rs12042763). Prostate cancer risk was not related to use of either nonaspirin NSAIDs or acetaminophen. These results contribute further evidence that aspirin may have chemopreventive activity against prostate cancer and highlight the need for additional research.

Am J Epidemiol. 2010 Sep 1;172(5):578-90

Effect of administration of fermented milk containing whey protein concentrate to rats and healthy men on serum lipids and blood pressure.

The effect of fermented milk supplemented with whey protein concentrate on the serum lipid level of rats was investigated. The serum total cholesterol level for the group fed fermented milk with both Lactobacillus casei TMC0409 and Streptococcus thermophilus TMC 1543 was significantly lower than that of the control group (P<0.05) in rats. Furthermore, the effect of the longterm intake of this fermented milk on the serum lipid level of twenty healthy adult men was investigated. During the 8-wk study, the volunteers consumed 200 ml of fermented milk or placebo in the morning and evening. Blood samples were drawn for analysis three times, just before taking the experimental diet, and after 4 wk and 8 wk of consumption. After 8 wk, the high density lipoprotein cholesterol level for the fermented milk group showed a significant rise after 4 wk (P<0.05), whereas that of the placebo group showed no change even after 4 wk (P>0.05). The triglyceride level for the fermented milk group lowered significantly after 4 wk (<0.05), whereas that of the placebo group showed no change even after 4 wk (P>0.05). The atherogenic index [(total cholesterol - high density lipoprotein cholesterol)/high-density lipoprotein cholesterol] for the fermented milk group decreased significantly from 4.24 to 3.52 (P<0.05). The systolic blood pressure lowered significantly by the intake of fermented milk (P<0.05) On the other hand, such effect was not observed in the placebo group (P>0.05). These results indicate potential of the development of fermented milk with multiple therapeutic effects.

J Dairy Sci. 2000 Feb;83(2):255-63

Effects of whey peptides on cardiovascular disease risk factors.

Previous studies have shown that peptides derived from milk proteins can improve blood pressure. Therefore, the authors tested the blood pressure-lowering effects of a hydrolyzed whey protein supplement rich in bioactive peptides. In a 6-week controlled study, 30 prehypertensive or stage 1 hypertensive subjects (blood pressure >or=120/80 mm Hg and <or=155/95 mm Hg) were randomized to receive 20 g/d of either a hydrolyzed whey protein (active treatment) or an unmodified whey protein (control treatment). Blood pressure, blood lipids, safety measures, side effects, and diet were evaluated throughout the trial. After completion of treatment, a 4-week follow-up was conducted. There was a mean reduction of 8.0+/-3.2 mm Hg in systolic blood pressure (P<.05) and of 5.5+/-2.1 mm Hg in diastolic blood pressure (P<.05) in the treatment group compared with the control group. Low-density lipoprotein cholesterol and high-sensitivity C-reactive protein were significantly improved by treatment. Whey-derived peptides might be a viable treatment option for prehypertensive and/or stage 1 hypertensive populations.

J Clin Hypertens (Greenwich). 2006 Nov;8(11):775-82

Angiotensin I converting enzyme-inhibitory activity of bovine, ovine, and caprine kappa-casein macropeptides and their tryptic hydrolysates.

This work evaluated the angiotensin-converting enzyme (ACE)-inhibitory activities of bovine, ovine, and caprine kappa-casein macropeptides (CMPs) and their tryptic hydrolysates. The results obtained indicate that bovine, ovine, and caprine CMPs exhibited moderate in vitro ACE-inhibitory activities that increased considerably after digestion under simulated gastrointestinal conditions. Active peptides could also be produced from CMPs via proteolysis with trypsin, with tryptic hydrolysates exhibiting a more extensive ACE-inhibitory activity than intact CMPs during simulated gastrointestinal digestion. Two active fractions were chromatographically separated from the tryptic hydrolysate of the bovine CMP, but their complexity hampered the assignment of the ACE-inhibitory activity to specific peptide sequences. Evidence for the release of the strong ACE-inhibitory tripeptide IPP was found upon simulation of the gastrointestinal digestion of peptides released by trypsin from the CMP sequence. These findings might help to promote further exploitation of cheese whey in the preparation of nutraceuticals for inclusion in the composition of functional food products with high added values.

J Food Prot. 2003 Sep;66(9):1686-92

Release of angiotensin I converting enzyme (ACE) inhibitory activity during in vitro gastrointestinal digestion: from batch experiment to semicontinuous model.

Gastrointestinal digestion is of major importance in the bioavailability of angiotensin I converting enzyme (ACE) inhibitory peptides, bioactive peptides with possible antihypertensive effects. In this study, the conditions of in vitro gastrointestinal digestion leading to the formation and degradation of ACE inhibitory peptides were investigated for pea and whey protein. In batch experiments, the digestion simulating the physiological conditions sufficed to achieve the highest ACE inhibitory activity, with IC(50) values of 0.076 mg/mL for pea and 0.048 mg/mL for whey protein. The degree of proteolysis did not correlate with the ACE inhibitory activity and was always higher for pea than whey. In a semicontinuous model of gastrointestinal digestion, response surface methodology studied the influence of temperature and incubation time in both the stomach and small intestine phases on the ACE inhibitory activity and degree of proteolysis. For pea protein, a linear model for the degree of proteolysis and a quadratic model for the ACE inhibitory activity could be constituted. Within the model, a maximal degree of proteolysis was observed at the highest temperature and the longest incubation time in the small intestine phase, while maximal ACE inhibitory activity was obtained at the longest incubation times in the stomach and small intestine phase. These results show that ACE inhibitory activity of pea and whey hydrolysates can be controlled by the conditions of in vitro gastrointestinal digestion.

J Agric Food Chem. 2003 Sep 10;51(19):5680-7

Structural analysis of new antihypertensive peptides derived from cheese whey protein by proteinase K digestion.

Whey protein was digested with one of seven kinds of proteases at 37 degrees C (trypsin, proteinase K, actinase E, thermolysin, or papain) or at 25 degrees C (pepsin or chymotrypsin) for 24 h. The digested samples were assayed for the inhibitory activity of angiotensin-converting enzyme and for changes in the systolic blood pressure caused in spontaneously hypertensive rats after gastric intubation. The strongest depressive effect on the systolic blood pressure (-55 mm Hg) was observed at 6 h after gastric intubation of the whey protein that was digested by proteinase K. Finally, six peptides were chromatographically isolated from the proteinase K digest by a combination of hydrophobic reversed-phase HPLC and gel filtration. The amino acid sequences and their origins were clarified as follows: Val-Tyr-Pro-Phe-Pro-Gly [beta-casein (CN); f 59-64], Gly-Lys-Pro (beta 2-microglobulin; f 18-20), Ile-Pro-Ala (beta-lactoglobulin; f 78-80), Phe-Pro (serum albumin; f 221-222; beta-CN, f 62-63, f 157-158, and f 205-206), Val-Tyr-Pro (beta-CN; f 59-61), and Thr-Pro-Val-Val-Val-Pro-Pro-Phe-Leu-Gln-Pro (beta-CN; f 80-90). Chemical synthesis of these six peptides confirmed that all peptides, except an undecapeptide, have antihypertensive activity in spontaneously hypertensive rats. The synthetic tripeptide Ile-Pro-Ala, originating from beta-lactoglobulin, showed the strongest antihypertensive activity (-31 mm Hg).

J Dairy Sci. 1998 Dec;81(12):3131-8

Angiotensin I-converting enzyme inhibitory properties of whey protein digests: concentration and characterization of active peptides.

The aim of this study was to identify whey-derived peptides with angiotensin I-converting enzyme (ACE) inhibitory activity. The bovine whey proteins alpha-lactalbumin and beta-lactoglobulin were hydrolysed with pepsin, trypsin, chymotrypsin, pancreatin, elastase or carboxypeptidase alone and in combination. The total hydrolysates were fractionated in a two step ultrafiltration process, first with a 30 kDa membrane and then with a 1 kDa membrane. Inhibition of ACE was analysed spectrophotometrically. The peptides were isolated by chromatography and identified by mass and sequencing analysis. The most potent inhibitory peptides were synthesized by the 9-fluorenylmethoxycarbonyl solid phase method. Inhibition of ACE was observed after hydrolysis with trypsin alone, and with an enzyme combination containing pepsin, trypsin and chymotrypsin. Whey protein digests gave a 50% inhibition (IC50) of ACE activity at concentration ranges within 345-1733 micrograms/ml. The IC50 values for the 1-30 kDa fractions ranged from 485 to 1134 micrograms/ml and for the < 1 kDa fraction from 109 to 837 mg/ml. Several ACE-inhibitory peptides were isolated from the hydrolysates by reversed-phase chromatography, and the potencies of the purified peptide fractions had IC50 values of 77-1062 microM. The ACE-inhibitory peptides identified were alpha-lactalbumin fractions (50-52), (99-108) and (104-108) and beta-lactoglobulin fractions (22-25), (32-40), (81-83), (94-100), (106-111) and (142-146).

J Dairy Res. 2000 Feb;67(1):53-64

In vitro study on digestion of peptides in Emmental cheese: analytical evaluation and influence on angiotensin I converting enzyme inhibitory peptides.

A simple in vitro protocol simulating gastrointestinal digestion of proteins and peptides to investigate the effect of digestive enzymes on the biological activity of peptides present in dairy products was developed. This protocol consisted in a 30 min incubation with pepsin followed by a 4 h incubation with trypsin or pancreatin. It was applied to an Emmental cheese water-soluble extract (WSE) and to a casein solution (as a control). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) allowed to monitor the digestion of proteins. Reversed-phase high-performance liquid chromatography (RP-HPLC) allowed to monitor the conversion of proteins and peptides into peptides and amino acids: it is proposed to use the mean retention time corresponding to the overall retention time distribution of molecules to assess the effect of digestive enzymes. The biological activity focused in this study was the angiotensin I converting enzyme (ACE) inhibitory activity. Digestion of Emmental WSE induced an increase of the ACE inhibition as compared to undigested WSE while a 10 kDa ultrafiltered WSE lost a part of its ACE inhibitory activity after digestion process. These results strongly suggest that digestive enzymes diminished the ACE inhibition by the peptides present in Emmental cheese WSE, while the digestion of peptides of high molecular weight would generate new ACE inhibitory peptides.

Nahrung. 2003 Apr;47(2):87-94

The impact of fermentation and in vitro digestion on the formation of angiotensin-I-converting enzyme inhibitory activity from pea and whey protein.

Pea and whey protein were fermented by Lactobacillus helveticus and Saccharomyces cerevisiae in monoculture and in combination at 28 and 37 degrees C in order to release angiotensin-I-converting enzyme (ACE) inhibitory peptides. The fermentation products were subjected to in vitro gastrointestinal digestion, and the digests of nonfermented samples served as controls. After fermentation, the ACE inhibitory activity (%) increased by 18 to 30% for all treatments, except for the fermentations of whey protein with Saccharomyces cerevisiae at 28 degrees C, where no significant change was observed. After digestion, however, both fermented and nonfermented samples reached maximum ACE inhibitory activity. The whey digests tended to have lower (50%) inhibitory concentrations (IC50; 0.14 to 0.07 mg/ml), hence, higher ACE inhibitory activity, than the pea digests (0.23 to 0.11 mg/ml). The nonfermented whey protein digest showed the highest ACE inhibitory activity of all. For pea protein, the nonfermented sample had the lowest IC50 value. These results suggest that in vitro gastrointestinal digestion was the predominant factor controlling the formation of ACE inhibitory activity, hence, indicating its importance in the bioavailability of ACE inhibitory peptides.

J Dairy Sci. 2003 Feb;86(2):429-38

A quantitative in silico analysis calculates the angiotensin I converting enzyme (ACE) inhibitory activity in pea and whey protein digests.

Angiotensin I converting enzyme (ACE) inhibitory peptides can induce antihypertensive effects after oral administration. By means of an ACE inhibitory peptide database, containing about 500 reported sequences and their IC(50) values, the different proteins in pea and whey were quantitatively evaluated as precursors for ACE inhibitory peptides. This analysis was combined with experimental data from the evolution in ACE inhibitory activity and protein degradation during in vitro gastrointestinal digestion. Pea proteins produced similar in silico scores and were degraded early in the in vitro digestion. High ACE inhibitory activity was observed after the simulated stomach phase and augmented slightly in the simulated small intestine phase. The major whey protein beta-lactoglobulin obtained the highest in silico scores, which corresponded with the fact that degradation of this protein in vitro only occurred from the simulated small intestine phase on and resulted in a 10-fold increase in the ACE inhibitory activity. Whey protein obtained total in silico scores of about 124 ml/mg, compared to 46 ml/mg for pea protein, indicating that whey protein would be a richer source of ACE inhibitory peptides than pea protein. Although beta-lactoglobulin is only partially digested, a higher ACE inhibitory activity was indeed found in the whey (IC(50) = 0.048 mg/ml) compared to the pea digest (IC(50) = 0.076 mg/ml). In silico gastrointestinal digestion of the highest scoring proteins in pea and whey, vicilin and albumin PA2, and beta-lactoglobulin, respectively, directly released a number of potent ACE inhibitory peptides. Several other ACE inhibitory sequences resisted in silico digestion by gastrointestinal proteases. Briefly, the quantitative in silico analysis will facilitate the study of precursor proteins on a large scale and the specific release of bioactive peptides.

Biochimie. 2004 Mar;86(3):231-9

Influence of the lactokinin Ala-Leu-Pro-Met-His-Ile-Arg (ALPMHIR) on the release of endothelin-1 by endothelial cells.

Milk protein-derived peptides with angiotensin-converting enzyme (ACE) inhibitory activity can reduce blood pressure in hypertensive subjects. The lactokinin Ala-Leu-Pro-Met-His-Ile-Arg (ALPMHIR) is an ACE-inhibitory peptide released by tryptic digestion from the milk protein beta-lactoglobulin. Its ACE-inhibitory activity is 100 times lower than that of captopril. The latter is known to inhibit the release of the vasoconstrictor endothelin-1 (ET-1) by endothelial cells. The effects of ALPMHIR on the endothelium are currently unknown. In this study, the influence of ALPMHIR on release of ET-1 by endothelial cells was investigated. The basal ET-1 release of the cells was reduced by 29% (p<0.01) in the presence of 1 mM ALPMHIR, compared to 42% (p<0.01) for 0.1 mM captopril. Addition of 10 U/ml thrombin to the incubation medium increased the release of ET-1 by 66% (p<0.01). Co-incubation of 10 U/ml thrombin with 1 microM captopril or with 0.1 mM ALPMHIR inhibited the stimulated ET-1 release by 45% (p<0.01) and by 32% (p<0.01), respectively. These data indicate that dietary peptides, such as ALPMHIR, can modulate ET-1 release by endothelial cells. These effects, among other mechanisms, may play a role in the anti-hypertensive effect of milk protein-derived peptides.

Regul Pept. 2004 Apr 15;118(1-2):105-9