Vitamin E and Prostate Cancer
Vitamin E is one of the most researched compounds in medicine. Vitamin E is actually a general name for potentially eight different compounds, so supplements can contain several forms and vitamin E in the diet also differs from the form found over the counter. There has been a strong interest in this supplement in the prostate cancer arena primarily because of a Finnish study that demonstrated a lower morbidity and mortality from this disease in men taking 50 mg of synthetic (alpha-tocopherol) vitamin E daily. In addition, observations from laboratory and clinical studies dealing with heart disease have found that gamma-tocopherol may also play a significant role in prevention; therefore, we decided to test the ability of this compound (versus synthetic vitamin E) to control the growth of a human prostate cancer cell line. Gamma-tocopherol was found to be superior to alpha-tocopherol in terms of cell inhibition in vitro. Both forms of vitamin E (and others) should be thoroughly evaluated in the future to provide the most effective chemoprevention information to the patient.
Vitamin Intake and Prostate Cancer
This population-based, case-control study in King County, Washington examined supplement use in 697 incident prostate cancer cases (ages 40-64) identified from the Puget Sound Surveillance, Epidemiology and End Results program registry and 666 controls recruited from the same overall population using random-digit dialing sampling. Participants reported their frequency of use of three types of multivitamins and single supplements of vitamins A, C, and E, calcium, iron, and zinc over the 2 years before diagnosis. Logistic regression analyses controlled for age, race, education, family history of prostate cancer, body mass index, number of prostate-specific antigen tests in the previous 5 years, and dietary fat intake. Adjusted odds ratios (95% confidence limits) for the contrast of > or =7/week versus no use were as follows: multivitamins, 0.96 (0.73, 1.26); vitamin A, 0.59 (0.32, 1.06); vitamin C, 0.77 (0.57, 1.04); vitamin E, 0.76 (0.54, 1.08); calcium, 1.04 (0.61, 1.78); iron, 0.50 (0.13, 1.76); and zinc, 0.55 (0.30, 1.00). Odds ratios differed little when cases were stratified by stage of disease at diagnosis or by histopathological grade. There were significant dose-response effects for zinc and ordered dose-response trends for vitamins C and E. Overall, these results suggest that multivitamin use is not associated with prostate cancer risk, but use of individual supplements of zinc, vitamin C, and vitamin E may be protective. Further study is needed to investigate the direct role of these dietary supplements, as well as the role of lifestyle variables associated with supplement use, on prostate cancer risk.
Antioxidants' Role in Prostate Cancer
Prostate cancer is the most common human malignancy and the second leading cause of cancer deaths among men in Western nations. Descriptive epidemiologic data suggest that androgens and/or environmental exposures, such as diet (in particular, dietary fat), play an important role in prostatic carcinogenesis. One plausible link between diet and prostate cancer is oxidative stress. This process refers to the generation of reactive oxygen species, which can then trigger a host of pro-carcinogenic processes. Recent studies also indicate that androgens increase oxidative stress within human prostate cancer cell lines. Recent data from our institution indicate that oxidative stress is higher within the benign epithelium of prostate cancer patients than men without the disease. This confirms our hypothesis and suggests that antioxidants such as lycopene, vitamin E, and selenium may play an important role in preventing disease progression. Large-scale clinical trials with some of these agents are currently in the design phase.
DHEA and Physical Movement
As old age results in reduced physical activity as well as less dehydroepiandrosterone (DHEA) and melatonin (MLT) production, low hormone levels may be a component of inactivity. Therefore, we studied the effects of DHEA and/or MLT supplementation on movement and resting in young and old female C57 black mice. Our results showed for the first time that old female C56BL/6 mice have significantly decreased physical activity. Their average speed and resting time were significantly higher than in young mice, whereas ambulatory time, distance traveled, and body movements when stationary (stereo time) were lower. DHEA supplementation significantly increased stereo time in old mice, while decreasing ambulatory time and distance traveled. MLT supplementation of old mice decreased average speed, resting time, and stereo time compared to untreated, old mice. Supplementation with MLT or DHEA, whose production is reduced in aging, restored physical activity levels in old mice. MLT also increased ambulatory time and distance traveled while reducing body movements of young mice.
Cardiovascular Disease Prevention
Based on laboratory and experimental evidence, it has been hypothesized that inflammation plays a fundamental role in atherogenesis and acute thrombosis. From an epidemiologic perspective, corroboration of this hypothesis has been provided by a series of prospective cohort studies which demonstrate that inflammatory parameters (such as fibrinogen, C reactive protein, and serum amyloid A), cellular adhesion molecules [such as intercellular adhesion molecule (ICAM)-1], and cytokines (such as interleukin-6) are all elevated at baseline among patients at risk for future coronary occlusion. Furthermore, data deriving from randomized clinical trials suggest that the efficacy of common preventive agents such as aspirin and hydroxy-methylglutaryl (HMG) CoA reductase inhibition may derive in part from interactions with the inflammatory system. Taken together, these data raise the possibility that therapies targeting chronic low-grade inflammation may provide novel future strategies for cardiovascular disease prevention.
Aspirin's Therapeutic Effects
BACKGROUND: Proinflammatory cytokines released by injured endothelium facilitate interaction of endothelial cells with circulating leukocytes and thus may contribute to development and progression of atherosclerosis. We investigated whether cytokines and C-reactive protein (CRP) are indicative of myocardial ischemia or of diseased vessels and whether they are influenced by aspirin treatment in patients with chronic stable angina. METHODS AND RESULTS: Plasma macrophage colony stimulating factor (MCSF), IL-1b, IL-6, and CRP were measured in 60 stable patients after 48-hour Holter monitoring and in 24 matched controls. All patients had angiographic documentation of disease and positive exercise ECGs. Patients with ischemia on Holter monitoring (n=40) received aspirin or placebo in a 6-week, randomized, double blind, crossover trial. Blood sampling was repeated at the end of each treatment phase (3 weeks). Compared to controls, patients had more than twice median MCSF (800 versus 372 pg/mL), IL-6 (3.9 versus 1.7 pg/mL), and CRP (1.25 versus 0.23 mg/L) levels (P<0.01 for all comparisons). MCSF was related to ischemia on Holter monitoring (P<0.01), to low ischemic threshold during exercise (P<0.01), and together with IL-1b to number of diseased vessels (P<0.05). MCSF, IL-6, and CRP were all reduced after 6 weeks of aspirin treatment (P<0.05). CONCLUSIONS: These findings suggest that cytokines are associated with both ischemia and anatomic extent of disease in patients with stable angina. Reduced cytokine and CRP levels by aspirin may explain part of aspirin's therapeutic action.
Stimulating Effects of Testosterone
Despite the widespread use of androgen in the treatment of hypogonadal men, its efficacy in restoring sexual behavior to hypogonadal patients has not been established in appropriately controlled behavioral studies. Accordingly, testosterone enanthate or vehicle was injected once every 4 weeks in a double blind experiment. The subjects were six adult males, aged 32-65 yr, two with gonadal failure and four with secondary hypogonadism. Two doses of testosterone (100 and 400 mg) were administered for approximately 5 months, with the treatments varied at random within and among subjects. Details of sexual activity and experience were followed by the use of daily logs. Frequencies of erections, including nocturnal erections and coitus, showed significant dose-related responses to androgen treatment which closely followed the fluctuations in the circulating testosterone level. As indicated by the Profile of Mood States test, behavioral responses did not appear to be mediated by changes in mood. We concluded that the stimulating effects of testosterone on sexual activity are rapid, reliable, and not due to a placebo effect. To maintain plasma testosterone and adequate sexual function within normal levels, even high doses of testosterone enanthate should be given no less frequency than once every 3 weeks.
Enhanced Sexual Function
PURPOSE: The effects of androgen replacement via a nonscrotal permeation enhanced testosterone transdermal system on the sexual function of men with hypogonadism were assessed. MATERIALS AND METHODS: An open label, multicenter study of testosterone supplementation and withdrawal was conducted with sexual function assessed by the Watts and Davidson questionnaires and RigiScan monitoring. RESULTS: When comparing results obtained during use of the testosterone transdermal system (with normalized testosterone levels) and during the androgen withdrawal period, nocturnal erections occurred more frequently with longer duration and greater rigidity, and patient assessments of sexual desire and weekly number of erections were higher. CONCLUSIONS: Sexual function improved significantly in men with hypogonadism treated with the testosterone transdermal system.