Life Extension Magazine®

Issue: Jan 2012

Natural Stress Relief

Treatment of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) comprises benign steatosis and steatohepatitis (NASH) and may lead to liver fibrosis, cirrhosis and hepatocellular carcinoma. Its prevalence is estimated to be 20% in the general population and 50-100% in patients with overweight and obesity. In about 15-30% of patients steatosis evolves to NASH which can only be diagnosed by means of a liver biopsy. NAFLD may be described as the hepatic component of the metabolic syndrome and is a consequence of the Western lifestyle. The pathogenesis is multifactorial; oxidative stress plays a crucial role in maintaining inflammation and progressive fibrosis. Lifestyle modification with weight loss and increased physical activity is the cornerstone of the treatment, which should take place in a multidisciplinary setting. To date, no specific registered drug for NAFLD treatment is available. Supportive drug therapy is mainly focused on aspects of the metabolic syndrome and chronic inflammation.

Ned Tijdschr Geneeskd. 2011;155:A3181

Coronary artery disease and cardiovascular outcomes in patients with non-alcoholic fatty liver disease.

OBJECTIVE: Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome and is associated with cardiovascular risk. The aim of this study was to determine the role of fatty liver in predicting coronary artery disease and clinical outcomes in patients undergoing coronary angiogram. METHODS: This was a prospective cohort study carried out in a University hospital. Consecutive patients who underwent coronary angiogram had ultrasound screening for fatty liver. Significant cardiovascular disease was defined as ≥50% stenosis in at least one coronary artery. The primary outcome was a composite end point comprising cardiovascular deaths, non-fatal myocardial infarction and the need for further coronary intervention during prospective follow-up. RESULTS: Among 612 recruited patients, 356 (58.2%) had fatty liver by ultrasonography, 318 (52.0%) had elevated serum alanine aminotransferase and 465 (76.0%) had significant coronary artery disease. Coronary artery disease occurred in 84.6% of patients with fatty liver and 64.1% of those without fatty liver (p<0.001). After adjusting for demographic and metabolic factors, fatty liver (adjusted OR 2.31; 95% CI 1.46 to 3.64) and alanine aminotransferase level (adjusted OR 1.01; 95% CI 1.00 to 1.02) remained independently associated with coronary artery disease. At a mean follow-up of 87±22 weeks, 30 (10.0%) patients with fatty liver and 18 (11.0%) patients without fatty liver reached the composite clinical end point (p=0.79). CONCLUSIONS: In patients with clinical indications for coronary angiogram, fatty liver is associated with coronary artery disease independently of other metabolic factors. However, fatty liver cannot predict cardiovascular mortality and morbidity in patients with established coronary artery disease.

Gut. 2011 May 20

Nonalcoholic fatty liver disease and diabetes mellitus: pathogenesis and treatment.

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) frequently coexist as they share the pathogenic abnormalities of excess adiposity and insulin resistance. Although type 1 diabetes mellitus (T1DM) is due to a relative lack of insulin, an increased prevalence of obesity and insulin resistance in this population means that NAFLD also commonly coexists with this condition. Both T2DM and NAFLD are associated with adverse outcomes of the other; T2DM is a risk factor for progressive liver disease and liver-related death in patients with NAFLD, whereas NAFLD may be a marker of cardiovascular risk and mortality in individuals with T2DM. Nonalcoholic steatohepatitis-a histological subtype of NAFLD characterized by hepatocyte injury and inflammation-is present in approximately 10% of patients with T2DM and is associated with an increased risk for the development of cirrhosis and liver-related death. Current treatment strategies aim to improve insulin resistance via weight loss and exercise, improve insulin sensitivity by the use of insulin-sensitizing agents (for example, pioglitazone) and reduce oxidative stress by the use of antioxidants, such as vitamin E. Pioglitazone and vitamin E supplementation show the most promise in improving hepatic steatosis and inflammation but have not yet been demonstrated to improve fibrosis, and concern remains regarding the toxicity of long-term use of both of these agents.

Nat Rev Endocrinol. 2011 May 10;7(8):456-65

Full-spectrum antioxidant therapy featuring astaxanthin coupled with lipoprivic strategies and salsalate for management of non-alcoholic fatty liver disease.

Owing to the worldwide epidemic of obesity, and the popularity of diets rich in sugar and saturated fat, nonalcoholic fatty liver disease (NAFLD) is increasingly common; it is usually associated with insulin resistance, and may be considered a component of the metabolic syndrome. The pathologies which can complicate hepatic steatosis—steatohepatitis, cirrhosis, and hepatic cancer--appear to result from an interaction of hepatic lipid overload and hepatic oxidative stress. It is therefore proposed that comprehensive regimens which effectively target each of these precipitating factors should achieve the best therapeutic benefit in NAFLD. Appropriate weight loss, and a diet low in saturated fat, glycemic index, and added sugars, should decrease hepatic lipid load. Measures which enhance adipocyte insulin sensitivity—such as pioglitazone, astaxanthin, and spirulina--may also be helpful in this regard, as may agents that boost hepatocyte capacity for fatty acid oxidation, such as metformin, carnitine, hydroxycitrate, long-chain omega-3 fats, and glycine. Astaxanthin and spirulina appear to have considerable potential for controlling the oxidative stress associated with NAFLD - the former because it may help to prevent the mitochondrial damage that renders mitochondria a key source of superoxide in this syndrome, the latter because it is exceptionally rich in phycocyanobilin, a phytochemical inhibitor of NAPDH oxidase. Other antioxidants which show some promise in this syndrome include high-dose folate, lipoic acid, melatonin, N-acetylcysteine, vitamin E, and taurine. Finally, treatment with salsalate, an inhibitor of IkappaB kinase-beta, has potential for blunting the adverse impact of hepatic steatosis on oxidative stress and inflammation.

Med Hypotheses. 2011 Oct;77(4):550-6

Nonalcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD), the most common liver disorder in the Western world, is a clinico-histopathological entity in which excessive triglyceride accumulation in the liver occurs. Non-alcoholic steatohepatitis (NASH) represents the necroinflammatory form, which can lead to advanced liver fibrosis, cirrhosis, and hepatocellular carcinoma. The pathogenesis of NAFLD/NASH is complex but increased visceral adiposity plus insulin resistance with increased free fatty acids release play an initial key role for the onset and perpetuation of liver steatosis. Further events in the liver include oxidative stress and lipid peroxidation, decreased antioxidant defences, early mitochondrial dysfunction, iron accumulation, unbalance of adipose-derived adipokines with a chronic proinflammatory status, and gut-derived microbial adducts. New gene polymorphisms increasing the risk of fatty liver, namely APOC3 and PNPLA3, have been lately identified allowing further insights into the pathogenesis of this condition. In our review pathophysiological, genetic, and essential diagnostic and therapeutic aspects of NAFLD are examined with future trends in this field highlighted.

Best Pract Res Clin Gastroenterol. 2010 Oct;24(5):695-708

Oxidant stress and antioxidant status among patients with nonalcoholic fatty liver disease (NAFLD).

BACKGROUND: One of the major pathogenic mechanisms for progression of nonalcoholic fatty liver disease (NAFLD) is oxidative stress. Recently, many studies have demonstrated the role of oxidative stress in NAFLD however, studies describing the antioxidant status in these patients are lacking. AIM: To study the levels of oxidative stress and antioxidant status among patients with NAFLD. PATIENTS AND METHODS: It was a prospective study in which 29 patients with NAFLD, 25 diseased controls with chronic viral hepatitis, and 23 healthy controls were enrolled. Apart from standard biochemical parameters, lipid peroxidation products were measured as thiobarbituric acid reactive substances. As measures of antioxidant capacity, superoxide dismutase, vitamin C levels and ferric reducing ability of plasma were measured. RESULTS: Level of thiobarbituric acid reactive substances was significantly higher among NAFLD patients as compared with diseased [4.7 nmol/mL (1.0 to 10.2) vs. 2.4 nmol/mL (0.8 to 10.7); P=0.02] or healthy controls [4.7 nmol/mL (1.0 to 10.2) vs. 1.8 nmol/mL (0.5 to 4.1); P=0.0001]. FRAP was found to be significantly higher in patients with NAFLD as compared with healthy controls [450.3 (197.6 to 733.3) vs. 340.8 (141.6 to 697.5) mumol Fe liberated; P=0.04], even though it was similar between NAFLD and diseased controls. Among NAFLD patients, there was no significant correlation between histological grading or staging and levels of pro and antioxidants. CONCLUSIONSProducts of lipid peroxidation are significantly increased among patients with NAFLD as compared with chronic viral hepatitis or healthy controls. Larger studies and newer markers of oxidative stress are required to clarify the association between oxidative stress and histological severity in NAFLD.

J Clin Gastroenterol. 2006 Nov-Dec;40(10): 930-5

Redox balance in the pathogenesis of nonalcoholic fatty liver disease: mechanisms and therapeutic opportunities.

Nonalcoholic fatty liver disease (NAFLD) is currently the most common liver disease in the world. It encompasses a histological spectrum, ranging from simple, nonprogressive steatosis to nonalcoholic steatohepatitis (NASH), which may progress to cirrhosis and hepatocellular carcinoma. While liver-related complications are confined to NASH, emerging evidence suggests both simple steatosis and NASH predispose to type 2 diabetes and cardiovascular disease. The pathogenesis of NAFLD is currently unknown, but accumulating data suggest that oxidative stress and altered redox balance play a crucial role in the pathogenesis of steatosis, steatohepatitis, and fibrosis. We will examine intracellular mechanisms, including mitochondrial dysfunction and impaired oxidative free fatty acid metabolism, leading to reactive oxygen species generation; additionally, the potential pathogenetic role of extracellular sources of reactive oxygen species in NAFLD, including increased myeloperoxidase activity and oxidized low density lipoprotein accumulation, will be reviewed. We will discuss how these mechanisms converge to determine the whole pathophysiological spectrum of NAFLD, including hepatocyte triglyceride accumulation, hepatocyte apoptosis, hepatic inflammation, hepatic stellate cell activation, and fibrogenesis. Finally, available animal and human data on treatment opportunities with older and newer antioxidant will be presented.

Antioxid Redox Signal. 2011 Sep 1;15(5):1325-65

Mitochondrial dysfunction precedes insulin resistance and hepatic steatosis and contributes to the natural history of non-alcoholic fatty liver disease in an obese rodent model.

BACKGROUND & AIMS: In this study, we sought to determine the temporal relationship between hepatic mitochondrial dysfunction, hepatic steatosis and insulin resistance, and to examine their potential role in the natural progression of non-alcoholic fatty liver disease (NAFLD) utilising a sedentary, hyperphagic, obese, Otsuka Long-Evans Tokushima Fatty (OLETF) rat model. METHODS: OLETF rats and their non-hyperphagic control Long-Evans Tokushima Otsuka (LETO) rats were sacrificed at 5, 8, 13, 20, and 40 weeks of age (n=6-8 per group). RESULTS: At 5 weeks of age, serum insulin and glucose and hepatic triglyceride (TG) concentrations did not differ between animal groups; however, OLETF animals displayed significant (p<0.01) hepatic mitochondrial dysfunction as measured by reduced hepatic carnitine palmitoyl-CoA transferase-1 activity, fatty acid oxidation, and cytochrome c protein content compared with LETO rats. Hepatic TG levels were significantly elevated by 8 weeks of age, and insulin resistance developed by 13 weeks in the OLETF rats. NAFLD progressively worsened to include hepatocyte ballooning, perivenular fibrosis, 2.5-fold increase in serum ALT, hepatic mitochondrial ultrastructural abnormalities, and increased hepatic oxidative stress in the OLETF animals at later ages. Measures of hepatic mitochondrial content and function including beta-hydroxyacyl-CoA dehydrogenase activity, citrate synthase activity, and immunofluorescence staining for mitochondrial carbamoyl phosphate synthetase-1, progressively worsened and were significantly reduced at 40 weeks in OLETF rats compared to LETO animals. CONCLUSIONS: Our study documents that hepatic mitochondrial dysfunction precedes the development of NAFLD and insulin resistance in the OLETF rats. This evidence suggests that progressive mitochondrial dysfunction contributes to the natural history of obesity-associated NAFLD.

J Hepatol. 2010 May;52(5):727-36

Effectiveness of the analogue of natural Schisandrin C (HpPro) in treatment of liver diseases: an experience in Indonesian patients.

OBJECTIVE: To determine the effect of dimethyl-4,4’-dimethoxy-5,6, 5’,6-dimethylene dioxy- biphenyl-2,2’-dicarboxylate (HpPro) on patients with acute and chronic liver diseases. METHODS: An open trial and a prospective randomized and controlled study were performed. The open trial consisted of 56 cases (16 cases of acute hepatitis, 20 cases of chronic hepatitis, 14 cases of liver cirrhosis and 6 cases of fatty liver). Controlled study consisted of 20 cases of Child A chronic hepatitis which were randomly treated with either HpPro or a mixture of known drugs which used as a liver protective agent in Indonesia as control for one week. The patients were then crossed over those two drugs in the next week. RESULTS: In the open trial, after 4 weeks’ treatment with HpPro 7.5 mg orally three times daily, acute hepatitis, chronic hepatitis and fatty liver cases showed rapid decrease of SGOT and SGPT. In the liver cirrhosis cases, SGOT and SGPT were decreased slowly. In the controlled trial, nine patients received HpPro 7.5 mg three times daily orally and eleven were treated with a mixture of known drugs as the controls. After one week treatment, HpPro group clinically showed significant decrease of SGPT and SGOT levels compared to control group (P = 0.035). At the second week, HpPro group showed significant decrease of SGOT compared to control group (P = 0.038) but the decrease of SGPT was not significant (P = 0.096). CONCLUSION: Treatment with HpPro is effective to reduce liver impairment in acute and chronic liver diseases on Indonesian patients. No side effect of HpPro was observed.

Chin Med J (Engl). 1998 Mar;111(3):248-51

A melon pulp concentrate rich in superoxide dismutase reduces stress proteins along the gastrointestinal tract of pigs.

OBJECTIVE: A melon (Cucumis melo LC.) pulp concentrate (MPC) rich in superoxide dismutase (SOD) activity was tested for its ability to decrease stress protein expressions along the gastrointestinal tract in a swine model. METHODS: Pig sextuplets weaned at 21 d of age were selected from among six litters (n = 36). After a 2-d fasting period, the pigs were fed at similar levels of intake of the control, MPC1, and MPC2 diets, which provided 0, 12.5, and 50 IU of added SOD per kilogram of food, respectively. One triplet of pigs per litter was slaughtered at 7 d and the second triplet at 14 d after weaning. SOD, catalase, and digestive enzymes were determined enzymatically and stress protein expressions by western blotting. RESULTS: Plasma SOD increased with MPC dose at day 14 (P < 0.05). Mucosal weights in the proximal and mid small intestine were lower at day 14 (P < 0.05), cecum tissue weight was greater (P < 0.05), and sucrase-specific activity in mid and distal small intestine mucosa was lower (P = 0.05) in the MPC2 group than in the control group. MPC supplementation essentially decreased (P < 0.05 to P < 0.001) stress proteins in the stomach (all), the mid small intestine (heat-shock protein-27, neuronal nitric oxide synthase) and the colon (heat-shock protein-70, neuronal nitric oxide synthase). CONCLUSION: A SOD-rich MPC provided at the dose of 50 IU/kg of food for up to 12 d was effective in lowering the level of stress proteins along the gastrointestinal tract of pigs after weaning.

Nutrition. 2011 Mar;27(3):358-63

Associations between liver histology and cortisol secretion in subjects with nonalcoholic fatty liver disease.

OBJECTIVES: To assess associations between the activity of hypothalamo-pituitary-adrenal (HPA) axis and liver histology in patients with nonalcoholic fatty liver disease (NAFLD). DESIGN AND PATIENTS: In a cross-sectional study, we enrolled 50 consecutive, overweight, NAFLD patients and 40 control subjects who were comparable for age, sex and body mass index (BMI). MEASUREMENTS: NAFLD (by liver biopsy), HPA axis activity (by 24-hour urinary free cortisol [UFC] excretion and serum cortisol levels after 1 mg dexamethasone), insulin resistance (by homeostasis model assessment: HOMA-IR), and metabolic syndrome (MetS) features. RESULTS: NAFLD patients had markedly higher (P < 0.001) 24-h UFC (149 +/- 24 vs. 90 +/- 16 nmol/day) and postdex suppression cortisol concentrations (32 +/- 10 vs. 16 +/- 7 nmol/l) than controls. The MetS and its individual components were more frequent among NAFLD patients. The marked differences in urinary/serum cortisol concentrations that were observed between the groups were little affected by adjustment for age, sex, BMI, waist circumference, systolic blood pressure, triglycerides, homeostasis model assessment for insulin resistance score and presence of diabetes. Importantly, 24-h UFC and postdex cortisol concentrations strongly correlated to hepatic necroinflammatory grade (P < 0.01) and fibrosis stage (P < 0.001) among NAFLD patients. By logistic regression analysis, 24-h UFC (odds ratio (OR) 1.80, 95%CI 1.3-2.8) or postdex cortisol concentrations (OR 1.95, 95%CI 1.4-3.1) independently predicted the severity of hepatic fibrosis, but not necroinflammation, after adjustment for potential confounders. CONCLUSIONS: These results suggest that NAFLD patients have a subtle, chronic overactivity in the HPA axis (that is closely associated with the severity of liver histopathology) leading to subclinical hypercortisolism that might be implicated in the development of NAFLD.

Clin Endocrinol (Oxf). 2006 Mar;64(3):337-41

Evaluation of blood oxidative stress-related parameters in alcoholic liver disease and non-alcoholic fatty liver disease.

Oxidative stress is implicated in the pathogenesis of liver disease. We investigated oxidative stress-related parameters and correlated with clinical findings in 35 non-alcoholic fatty liver disease (NAFLD) patients, 38 alcoholic liver disease (ALD) patients and 38 normal subjects. NAFLD patients showed significantly higher body mass index, cholesterol, LDL-cholesterol, VLDL-cholesterol levels and transaminase activities compared to the other two groups. Haematological parameters were significantly altered in ALD patients and were reported only in male subjects. Glutathione content, catalase activity, glutathione reductase activity and glutathione peroxidase activity in NAFLD patients were reduced by 10.7 %, 18.5%, 8.1% and 16.8%, respectively, and in ALD patients by 21.8%, 29.6%, 24.3% and 45.3%, respectively, compared to the normal group. However, thiobarbituric acid reactive substance content, superoxide dismutase activity and glutathione s-transferase activity were increased by 35.2%, 31.6% and 5.4%, respectively, in NAFLD patients, and in ALD patients by 75.2%, 72.7% and 32.4%, respectively, compared to the normal group. Oxidative stress is associated with collagen production and leads to fibrosis. Type IV collagen level in NAFLD patients (190.6 +/- 83 ng/mL) was significantly higher than in the normal group (124.5 +/- 14.5 ng/mL) and lower than in ALD patients (373.4 +/- 170 ng/mL). While type IV collagen level of >124 ng/mL was a predictor of NAFLD patients from normal subjects, elevated ALT (>40 IU/L) activity could discriminate either of the liver disease patients from normal subjects.

Scand J Clin Lab Invest. 2008;68(4):323-34

Effects of thiamine and benfotiamine on intracellular glucose metabolism and relevance in the prevention of diabetic complications.

Thiamine (vitamin B1) is an essential cofactor in most organisms and is required at several stages of anabolic and catabolic intermediary metabolism, such as intracellular glucose metabolism, and is also a modulator of neuronal and neuro-muscular transmission. Lack of thiamine or defects in its intracellular transport can cause a number of severe disorders. Thiamine acts as a coenzyme for transketolase (TK) and for the pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase complexes, enzymes which play a fundamental role for intracellular glucose metabolism. In particular, TK is able to shift excess fructose-6-phosphate and glycerhaldeyde-3-phosphate from glycolysis into the pentose-phosphate shunt, thus eliminating these potentially damaging metabolites from the cytosol. Diabetes might be considered a thiamine-deficient state, if not in absolute terms at least relative to the increased requirements deriving from accelerated and amplified glucose metabolism in non-insulin dependent tissues that, like the vessel wall, are prone to complications. A thiamine/TK activity deficiency has been described in diabetic patients, the correction of which by thiamine and/or its lipophilic derivative, benfotiamine, has been demonstrated in vitro to counteract the damaging effects of hyperglycaemia on vascular cells. Little is known, however, on the positive effects of thiamine/benfotiamine administration in diabetic patients, apart from the possible amelioration of neuropathic symptoms. Clinical trials on diabetic patients would be necessary to test this vitamin as a potential and inexpensive approach to the prevention and/or treatment of diabetic vascular complications.

Acta Diabetol. 2008 Sep;45(3):131-41

Efficacy of benfotiamine versus thiamine on function and glycation products of peripheral nerves in diabetic rats.

In rats with streptozotocin (STZ) induced diabetes the effect of (water soluble) thiamine nitrate and of (lipid soluble) benfotiamine on peripheral nerve function (motor nerve conduction velocity) as well as on the formation of advanced glycation end-products in peripheral nerve tissue was studied. In one group of animals drug administration was started immediately after diabetes induction (prevention study) and in another group two months after diabetes induction (treatment study). Motor nerve conduction velocity (NCV) dropped by 10.5% in diabetic animals, carboxymethyl-lysine (CML) rose to a 3.5 fold concentration, deoxyglucosone (3DG)-type AGE formation was increased 5.1 fold compared with controls. After three months preventive administration of both vitamin B(1) preparations NCV had increased substantially compared with results in diabetic controls. It was nearly normal after six months with benfotiamine, while the administration of thiamine nitrate resulted in no further amelioration. NCV was nearly normalized after six months of benfotiamine application but not with thiamine. Furthermore, benfotiamine induced a major inhibition of neural imidazole-type AGE formation and completely prevented diabetes induced glycoxidation products (CML). Treatment with thiamine did not significantly affect AGE or cmL levels. Unlike treatment with water-soluble thiamine nitrate timely administration of liposoluble prodrug benfotiamine was effective in the prevention of functional damage and of AGE and cmL formation in nerves of diabetic rats.

Exp Clin Endocrinol Diabetes. 2001;109(6):330-6.

Benfotiamine, a synthetic S-acyl thiamine derivative, has different mechanisms of action and a different pharmacological profile than lipid-soluble thiamine disulfide derivatives.

BACKGROUND: Lipid-soluble thiamine precursors have a much higher bioavailability than genuine thiamine and therefore are more suitable for therapeutic purposes. Benfotiamine (S-benzoylthiamine O-monophosphate), an amphiphilic S-acyl thiamine derivative, prevents the progression of diabetic complications, probably by increasing tissue levels of thiamine diphosphate and so enhancing transketolase activity. As the brain is particularly sensitive to thiamine deficiency, we wanted to test whether intracellular thiamine and thiamine phosphate levels are increased in the brain after oral benfotiamine administration. RESULTS: Benfotiamine that is practically insoluble in water, organic solvents or oil was solubilized in 200 mM hydroxypropyl-beta-cyclodextrin and the mice received a single oral administration of 100 mg/kg. Though thiamine levels rapidly increased in blood and liver to reach a maximum after one or two hours, no significant increase was observed in the brain. When mice received a daily oral administration of benfotiamine for 14 days, thiamine derivatives were increased significantly in the liver but not in the brain, compared to control mice. In addition, incubation of cultured neuroblastoma cells with 10 muM benfotiamine did not lead to increased intracellular thiamine levels. Moreover, in thiamine-depleted neuroblastoma cells, intracellular thiamine contents increased more rapidly after addition of thiamine to the culture medium than after addition of benfotiamine for which a lag period was observed. CONCLUSION: Our results show that, though benfotiamine strongly increases thiamine levels in blood and liver, it has no significant effect in the brain. This would explain why beneficial effects of benfotiamine have only been observed in peripheral tissues, while sulbutiamine, a lipid-soluble thiamine disulfide derivative, that increases thiamine derivatives in the brain as well as in cultured cells, acts as a central nervous system drug. We propose that benfotiamine only penetrates the cells after dephosphorylation by intestinal alkaline phosphatases. It then enters the bloodstream as S-benzoylthiamine that is converted to thiamine in erythrocytes and in the liver. Benfotiamine, an S-acyl derivative practically insoluble in organic solvents, should therefore be differentiated from truly lipid-soluble thiamine disulfide derivatives (allithiamine and the synthetic sulbutiamine and fursultiamine) with a different mechanism of absorption and different pharmacological properties.

BMC Pharmacol. 2008 Jun 12;8:10

The multifaceted therapeutic potential of benfotiamine.

Thiamine, known as vitamin B(1), plays an essential role in energy metabolism. Benfotiamine (S-benzoylthiamine O-monophoshate) is a synthetic S-acyl derivative of thiamine. Once absorbed, benfotiamine is dephosphorylated by ecto-alkaline phosphatase to lipid-soluble S-benzoylthiamine. Transketolase is an enzyme that directs the precursors of advanced glycation end products (AGEs) to pentose phosphate pathway. Benfotiamine administration increases the levels of intracellular thiamine diphosphate, a cofactor necessary for the activation transketolase, resulting in the reduction of tissue level of AGEs. The elevated level of AGEs has been implicated in the induction and progression of diabetes-associated complications. Chronic hyperglycemia accelerates the reaction between glucose and proteins leading to the formation of AGEs, which form irreversible cross-links with many macromolecules such as collagen. In diabetes, AGEs accumulate in tissues at an accelerated rate. Experimental studies have elucidated that binding of AGEs to their specific receptors (RAGE) activates mainly monocytes and endothelial cells and consequently induces various inflammatory events. Moreover, AGEs exaggerate the status of oxidative stress in diabetes that may additionally contribute to functional changes in vascular tone control observed in diabetes. The anti-AGE property of benfotiamine certainly makes it effective for the treatment of diabetic neuropathy, nephropathy and retinopathy. Interestingly, few recent studies demonstrated additional non-AGE-dependent pharmacological actions of benfotiamine. The present review critically analyzed the multifaceted therapeutic potential of benfotiamine.

Pharmacol Res. 2010 Jun;61(6):482-8

Benfotiamine blocks three major pathways of hyperglycemic damage and prevents experimental diabetic retinopathy.

Three of the major biochemical pathways implicated in the pathogenesis of hyperglycemia induced vascular damage (the hexosamine pathway, the advanced glycation end product (AGE) formation pathway and the diacylglycerol (DAG)-protein kinase C (PKC) pathway) are activated by increased availability of the glycolytic metabolites glyceraldehyde-3-phosphate and fructose-6-phosphate. We have discovered that the lipid-soluble thiamine derivative benfotiamine can inhibit these three pathways, as well as hyperglycemia-associated NF-kappaB activation, by activating the pentose phosphate pathway enzyme transketolase, which converts glyceraldehyde-3-phosphate and fructose-6-phosphate into pentose-5-phosphates and other sugars. In retinas of diabetic animals, benfotiamine treatment inhibited these three pathways and NF-kappaB activation by activating transketolase, and also prevented experimental diabetic retinopathy. The ability of benfotiamine to inhibit three major pathways simultaneously might be clinically useful in preventing the development and progression of diabetic complications.

Nat Med. 2003 Mar;9(3):294-9

Benfotiamine exhibits direct antioxidative capacity and prevents induction of DNA damage in vitro.

BACKGROUND: Complications in diabetes mellitus are partially mediated by enhanced formation of reactive oxygen species. Among the factors involved in reactive oxygen species formation, advanced glycation end products play a key role. Owing to a reduced activity of the enzyme transketolase, which requires diphosphorylated thiamine (vitamin B(1)) as cofactor, an accumulation of those deleterious glucose metabolites especially in diabetic patients can be observed. Benfotiamine, a lipophilic thiamine diphosphate prodrug, prevented early renal and retinal changes in animal studies, and reduced neuropathic pain in clinical studies. Several mechanisms for these activities have been described. We investigated for the first time direct antioxidant abilities of benfotiamine. Additionally, a potential DNA protective effect of benfotiamine was analysed. METHODS: Oxidative stress was detected by flow cytometry, antioxidative capacity was measured with the ferric reducing ability of plasma (FRAP) assay, two endpoints for genomic damage were assessed: the comet assay and the micronucleus test, and the expression and activity of transketolase was quantified. RESULTS: Benfotiamine prevented oxidative stress induced by the mutagen 4-nitroquinoline-1-oxide (NQO), the uremic toxin indoxyl sulfate, and the peptide hormone angiotensin II in three different kidney cell lines. Cell-free experiments showed a direct antioxidant effect of benfotiamine, which might account for the protective effect. Oxidative DNA damage, induced by angiotensin II, was completely prevented by benfotiamine. Incubation with benfotiamine increased transketolase expression and activity in the cells. CONCLUSIONS: Benfotiamine shows a direct antioxidant action. This effect of benfotiamine may be involved in the improvement of diabetic late complications, including peripheral neuropathy.

Diabetes Metab Res Rev. 2008 Jul-Aug;24(5):371-7

Benfotiamine prevents macro- and microvascular endothelial dysfunction and oxidative stress following a meal rich in advanced glycation end products in individuals with type 2 diabetes.

OBJECTIVE: Diabetes is characterized by marked postprandial endothelial dysfunction induced by hyperglycemia, hypertriglyceridemia, advanced glycation end products (AGEs), and dicarbonyls (e.g., methylglyoxal [MG]). In vitro hyperglycemia-induced MG formation and endothelial dysfunction could be blocked by benfotiamine, but in vivo effects of benfotiamine on postprandial endothelial dysfunction and MG synthesis have not been investigated in humans until now. RESEARCH DESIGN AND METHODS: Thirteen people with type 2 diabetes were given a heat-processed test meal with a high AGE content (HAGE; 15.100 AGE kU, 580 kcal, 54 g protein, 17 g lipids, and 48 g carbohydrates) before and after a 3-day therapy with benfotiamine (1,050 mg/day). Macrovascular flow-mediated dilatation (FMD) and microvascular reactive hyperemia, along with serum markers of endothelial disfunction (E-selectin, vascular cell adhesion molecule-1, and intracellular adhesion molecule-1), oxidative stress, AGE, and MG were measured during both test meal days after an overnight fast and then at 2, 4, and 6 h postprandially. RESULTS: The HAGE induced a maximum reactive hyperemia decrease of -60.0% after 2 h and a maximum FMD impairment of -35.1% after 4 h, without affecting endothelium-independent vasodilatation. The effects of HAGE on both FMD and reactive hyperemia were completely prevented by benfotiamine. Serum markers of endothelial dysfunction and oxidative stress, as well as AGE, increased after HAGE. These effects were significantly reduced by benfotiamine. CONCLUSIONS: Our study confirms micro- and macrovascular endothelial dysfunction accompanied by increased oxidative stress following a real-life, heat-processed, AGE-rich meal in individuals with type 2 diabetes and suggests benfotiamine as a potential treatment.

Diabetes Care. 2006 Sep;29(9):2064-71

High-dose benfotiamine rescues cardiomyocyte contractile dysfunction in streptozotocin-induced diabetes mellitus.

Diabetic cardiomyopathy is characterized by cardiac dysfunction. This study was designed to examine the effect of benfotiamine, a lipophilic derivative of thiamine, on streptozotocin (STZ)-induced cardiac contractile dysfunction in mouse cardiomyocytes. Adult male FVB mice were made diabetic with a single injection of STZ (200 mg/kg ip). Fourteen days later, control and diabetic (fasting plasma glucose > 13.9 mM) mice were put on benfotiamine therapy (100 ip) for another 14 days. Mechanical and intracellular Ca2+ properties were evaluated in left ventricular myocytes using an IonOptix MyoCam system. The following indexes were evaluated: peak shortening (PS), time to PS (TPS), time to 90% relengthening (TR90), maximal velocity of shortening/relengthening, resting and rise of intracellular Ca2+ in response to electrical stimulus, sarcoplasmic reticulum (SR) Ca2+ load, and intracellular Ca2+ decay rate (tau). Two- or four-week STZ treatment led to hyperglycemia, prolonged TPS and TR90, reduced SR Ca2+ load, elevated resting intracellular Ca2+ level and prolonged tau associated with normal PS, maximal velocity of shortening/relengthening, and intracellular Ca2+ rise in response to electrical stimulus. Benfotiamine treatment abolished prolongation in TPS, TR90, and tau, as well as reduction in SR Ca2+ load without affecting hyperglycemia and elevated resting intracellular Ca2+. Diabetes triggered oxidative stress, measured by GSH-to-GSSG ratio and formation of advanced glycation end product (AGE) in the hearts. Benfotiamine treatment alleviated oxidative stress without affecting AGE or protein carbonyl formation. Collectively, our results indicated that benfotiamine may rescue STZ-induced cardiomyocyte dysfunction but not AGE formation in short-term diabetes.

J Appl Physiol. 2006 Jan;100(1):150-6

Benfotiamine is similar to thiamine in correcting endothelial cell defects induced by high glucose.

We investigated the hypothesis that benfotiamine, a lipophilic derivative of thiamine, affects replication delay and generation of advanced glycosylation end-products (AGE) in human umbilical vein endothelial cells cultured in the presence of high glucose. Cells were grown in physiological (5.6 mM) and high (28.0 mM) concentrations of D-glucose, with and without 150 microM thiamine or benfotiamine. Cell proliferation was measured by mitochondrial dehydrogenase activity. AGE generation after 20 days was assessed fluorimetrically. Cell replication was impaired by high glucose (72.3%+/-5.1% of that in physiological glucose, p=0.001). This was corrected by the addition of either thiamine (80.6%+/-2.4%, p=0.005) or benfotiamine (87.5%+/-8.9%, p=0.006), although it not was completely normalized (p=0.001 and p=0.008, respectively) to that in physiological glucose. Increased AGE production in high glucose (159.7%+/-38.9% of fluorescence in physiological glucose, p=0.003) was reduced by thiamine (113.2%+/-16.3%, p=0.008 vs. high glucose alone) or benfotiamine (135.6%+/-49.8%, p=0.03 vs. high glucose alone) to levels similar to those observed in physiological glucose. Benfotiamine, a derivative of thiamine with better bioavailability, corrects defective replication and increased AGE generation in endothelial cells cultured in high glucose, to a similar extent as thiamine. These effects may result from normalization of accelerated glycolysis and the consequent decrease in metabolites that are extremely active in generating nonenzymatic protein glycation. The potential role of thiamine administration in the prevention or treatment of vascular complications of diabetes deserves further investigation.

Acta Diabetol. 2001;38(3):135-8

PP2A contributes to endothelial death in high glucose: inhibition by benfotiamine.

Endothelial death is critical in diabetic vascular diseases, but regulating factors have been only partially elucidated. Phosphatases play important regulatory roles in cell metabolism, but have not previously been implicated in hyperglycemia-induced cell death. We investigated the role of the phosphatase, type 2A protein phosphatase (PP2A), in hyperglycemia-induced changes in signaling and death in bovine aortic endothelial cells (BAEC). We explored also the influence of benfotiamine on this phosphatase. Activation of PP2A was assessed in BAEC by the extent of methylation and measurement of activity, and the enzyme was inhibited using selective pharmacological (okadaic acid, sodium fostriecin) and molecular (small interfering RNA) approaches. BAECs cultured in 30 mM glucose significantly increased PP2A methylation and activity, and PP2A inhibitors blocked these abnormalities. PP2A activity was increased also in aorta and retina from diabetic rats. NF-B activity and cell death in BAEC were significantly increased in 30 mM glucose and inhibited by PP2A inhibition. NF-B played a role in the hyperglycemia-induced death of BAEC, since blocking its translocation with SN50 also inhibited cell death. Inhibition of PP2A blocked the hyperglycemia-induced dephosphorylation of NF-B and Bad, thus favoring cell survival. Incubation of benfotiamine with BAEC inhibited the high glucose-induced activation of PP2A and NF-B and cell death, as well as several other metabolic defects, which likewise were inhibited by inhibitors of PP2A. Activation of PP2A contributes to endothelial cell death in high glucose, and beneficial actions of benfotiamine are due, at least in part, to inhibition of PP2A activation.

Am J Physiol Regul Integr Comp Physiol. 2010 Dec;299(6):R1610-7

Vitamin B1 analog benfotiamine prevents diabetes-induced diastolic dysfunction and heart failure through Akt/Pim-1-mediated survival pathway.

BACKGROUND: The increasing incidence of diabetes mellitus will result in a new epidemic of heart failure unless novel treatments able to halt diabetic cardiomyopathy early in its course are introduced. This study aimed to determine whether the activity of the Akt/Pim-1 signaling pathway is altered at critical stages of diabetic cardiomyopathy and whether supplementation with vitamin B1 analog benfotiamine (BFT) helps to sustain the above prosurvival mechanism, thereby preserving cardiomyocyte viability and function. METHODS AND RESULTS: Untreated streptozotocin-induced type 1 or leptin-receptor mutant type 2 diabetic mice showed diastolic dysfunction evolving to contractile impairment and cardiac dilatation and failure. BFT (70 mg/kg(-1)/d(-1)) improved diastolic and systolic function and prevented left ventricular end-diastolic pressure increase and chamber dilatation in both diabetic models. Moreover, BFT improved cardiac perfusion and reduced cardiomyocyte apoptosis and interstitial fibrosis. In hearts of untreated diabetic mice, the expression and activity of Akt/Pim-1 signaling declined along with O-N-acetylglucosamine modification of Akt, inhibition of pentose phosphate pathway, activation of oxidative stress, and accumulation of glycation end products. Furthermore, diabetes reduced pSTAT3 independently of Akt. BFT inhibited these effects of diabetes mellitus, thereby conferring cardiomyocytes with improved resistance to high glucose-induced damage. The phosphoinositide-3-kinase inhibitor LY294002 and dominant-negative Akt inhibited antiapoptotic action of BFT-induced and Pim-1 upregulation in high glucose-challenged cardiomyocytes. CONCLUSIONS: These results show that BFT protects from diabetes mellitus-induced cardiac dysfunction through pleiotropic mechanisms, culminating in the activation of prosurvival signaling pathway. Thus, BFT merits attention for application in clinical practice.

Circ Heart Fail. 2010 Mar;3(2):294-305

The defensive effect of benfotiamine in sodium arsenite-induced experimental vascular endothelial dysfunction.

The present study has been designed to investigate the effect of benfotiamine, a thiamine derivative, in sodium arsenite-induced vascular endothelial dysfunction (VED) in rats. Sodium arsenite (1.5 mg(-1) kg(-1) day(-1) i.p., 2 weeks) was administered in rats to produce VED. The development of VED was assessed by employing isolated aortic ring preparation and estimating the serum and aortic concentrations of nitrite/nitrate. Further, the integrity of vascular endothelium in thoracic aorta was assessed by scanning electron microscopy. Moreover, the oxidative stress was assessed by estimating serum thiobarbituric acid reactive substances (TBARS) and aortic superoxide anion generation. The administration of sodium arsenite markedly produced VED by attenuating acetylcholine-induced endothelium-dependent relaxation, decreasing serum and aortic concentrations of nitrite/nitrate, and impairing the integrity of vascular endothelium. Further, sodium arsenite produced oxidative stress by increasing serum TBARS and aortic superoxide generation. The treatment with benfotiamine (25, 50, and 100 mg(-1) kg(-1) day(-1) p.o.) or atorvastatin (30 mg(-1) kg(-1) day(-1) p.o., a standard agent) prevented sodium arsenite-induced VED and oxidative stress. However, the beneficial effects of benfotiamine in preventing the sodium arsenite-induced VED were attenuated by co-administration with N-omega-nitro-L: -arginine methyl ester (L: -NAME) (25 mg(-1) kg(-1) day(-1), i.p.), an inhibitor of NOS. Thus, it may be concluded that benfotiamine reduces oxidative stress and activates endothelial nitric oxide synthase to enhance the generation and bioavailability of NO and subsequently improves the integrity of vascular endothelium to prevent sodium arsenite-induced experimental VED.

Biol Trace Elem Res. 2010 Oct;137(1):96-109

Self-reported psychological stress and the risk of breast cancer: A case-control study.

The aim of this study was to examine the relationship between severe life events and breast cancer risk. This study was based on a case-control examination of 858 Polish invasive breast cancer cases and 1085 controls matched for age and place of residence. Data on life events, sociodemographic characteristic, reproductive factors, family history of breast cancer, current weight and height, and lifestyle habits were collected between January 2003 and May 2007 using a self-administered questionnaire. Odds ratios with 95% confidence intervals were estimated as the measure of the relationship between life event stress and breast cancer risk using unconditional logistic regression analyses. After adjustment for potential breast cancer risk factors, women with four to six individual major life events had 5.33 times higher risk for breast cancer, compared with those in the lowest quartile. Similarly, women with a lifetime life change score greater than 210 had about 5 times higher risk compared to women with corresponding scores in the range 0-70. Several life events (death of a close family member, personal injury or illness, imprisonment/trouble with the law, retirement) were significantly associated with breast cancer risk. These findings suggest that major life events can play an important role in the etiology of breast cancer.

Stress. 2011 Aug 29

Optimum conditions for the water extraction of L-theanine from green tea.

Theanine is a unique non-protein amino acid found in tea (Camellia sinensis). It contributes to the favourable umami taste of tea and is linked to various beneficial effects in humans. There is an increasing interest in theanine as an important component of tea, as an ingredient for novel functional foods and as a dietary supplement. Therefore, optimal conditions for extracting theanine from tea are required for the accurate quantification of theanine in tea and as an efficient first step for its purification. This study examined the effects of four different extraction conditions on the yield of theanine from green tea using water and applied response surface methodology to further optimise the extraction conditions. The results showed that temperature, extraction time, ratio of water-to-tea and tea particle sizes had significant impacts on the extraction yield of theanine. The optimal conditions for extracting theanine from green tea using water were found to be extraction at 80 °C for 30 min with a water-to-tea ratio of 20:1 mL/g and a tea particle size of 0.5-1 mm.

J Sep Sci. 2011 Sep;34(18):2468-74

L-theanine: properties, synthesis and isolation from tea.

Theanine is a non-protein amino acid that occurs naturally in the tea plant (Camellia sinensis) and contributes to the favourable taste of tea. It is also associated with effects such as the enhancement of relaxation and the improvement of concentration and learning ability. It is also linked with health benefits including the prevention of certain cancers and cardiovascular disease, the promotion of weight loss and enhanced performance of the immune system. Thus, there has been a significant rise in the demand for theanine. While theanine has been chemically and biologically synthesised, techniques to isolate theanine from natural sources remain an important area of research. In this review article, the properties and health benefits of theanine are summarised and the synthesis and isolation of theanine are reviewed and discussed. Future perspectives for the isolation of theanine from natural sources are also outlined.

J Sci Food Agric. 2011 Aug 30;91(11):1931-9

Behavioral and molecular evidence for psychotropic effects in L: -theanine.

RATIONALE: L: -Theanine (N-ethyl-L: -glutamine) is an amino acid uniquely found in green tea and historically considered to be a relaxing agent. It is a glutamate derivative and has an affinity for glutamatergic receptors. However, its psychotropic effects remain unclear. OBJECTIVES: To elucidate effects of L: -theanine on psychiatric disease-related behaviors in mice and its molecular basis focusing on brain-derived neurotrophic factor (BDNF) and N-methyl-D: -aspartate (NMDA) receptor. METHODS: We examined the effects of L: -theanine on behaviors in mice by using the open-field test (OFT), forced swim test (FST), elevated plus-maze test (EPMT), and prepulse inhibition (PPI) of acoustic startle. By western blot analysis, we looked at the effect of L: -theanine on the expression of BDNF and related proteins in the hippocampus and cerebral cortex. To determine whether L: -theanine has agonistic action on the NMDA receptor, we performed Fluo-3 intracellular Ca(2+) imaging in cultured cortical neurons. RESULTS: Single administration of L: -theanine significantly attenuated MK-801-induced deficits in PPI. Subchronic administration (3-week duration) of L: -theanine significantly reduced immobility time in the FST and improved baseline PPI. Western blotting analysis showed increased expression of BDNF protein in the hippocampus after subchronic administration of L: -theanine. In cultured cortical neurons, L: -theanine significantly increased the intracellular Ca(2+) concentration, and this increase was suppressed by competitive and non-competitive NMDA receptor antagonists (AP-5 and MK-801, respectively). CONCLUSIONS: Our results suggest that L: -theanine has antipsychotic-like and possibly antidepressant-like effects. It exerts these effects, at least in part, through induction of BDNF in the hippocampus and the agonistic action of L: -theanine on the NMDA receptor.

Psychopharmacology (Berl). 2011 Aug 23

Theogallin and L-theanine as active ingredients in decaffeinated green tea extract: I. electrophysiological characterization in the rat hippocampus in-vitro.

The in-vitro hippocampus slice preparation was used to mimic a physiological situation where nervous tissue is exposed directly to the water soluble extract of green tea and some of its constituents. This investigation provides evidence that L-theanine- and theogallin-enriched decaffeinated green tea extract is able to change the physiological pattern of electrical hippocampus activity in a concentration dependent manner (EC50 3 mg L(-1)). Of the seven fractions or single components tested (fraction containing all amino acids without L-theanine, fractions containing all amino acids plus L-theanine, glutamic acid, theogallin, its metabolites quinic acid and gallic acid, and L-theanine alone), glutamic acid produced the strongest changes in terms of increased population spike amplitude after single stimuli and increased long-term potentiation, commonly taken as representative for enhancement of spatial and time dependent memory. The presence of theogallin alone shifted the activity in the same direction. Similar results as with theogallin were obtained in the presence of quinic acid. No effect was seen with gallic acid. Opposite changes (decrease of population spike amplitude and attenuated long-term potentiation) were observed in the presence of L-theanine alone. No effects were detected during the addition of the amino acid mixture unless L-theanine was added, leading to a decrease of the responses as observed for the action of L-theanine alone. The results provide evidence for the involvement of several active principles in the action of enriched green tea extract on electrical brain activity. The overall enhancement of hippocampal pyramidal cell responses as observed for the crude extract seems to be due to the combined action of glutamic acid and theogallin (or its presumable metabolite quinic acid), whereas L-theanine seems to have an opposite effect. However, this action was not strong enough to antagonize the effects of glutamic acid and theogallin. The results are in line with the observation that the tested green tea extract improves cognition at concomitant mental relaxation in man.

J Pharm Pharmacol. 2007 Aug;59(8):1131-6

Antidepressant-like Effects of L-theanine in the Forced Swim and Tail Suspension Tests in Mice.

L-theanine (-glutamylethyla-mide), an amino acid component of green tea, has been shown to reduce mental and physical stress, and to improve memory function. In this study, the antidepressant effect of L-theanine was investigated in mice using the forced swim test, tail suspension test, open-field test and reserpine test. L-theanine produced an antidepressant-like effect, since the administration of L-theanine at doses of 1, 4 and 20 mg/kg for 10 successive days significantly reduced the immobility time in both the forced swim test and tail suspension test, compared with the control group, without accompanying changes in ambulation in the open-field test. Moreover, L-theanine significantly antagonized reserpine-induced ptosis and hypothermia. Taken together, these results indicate that L-theanine possessed an antidepressant-like effect in mice, which may be mediated by the central monoaminergic neurotransmitter system.

Phytother Res. 2011 Nov;25(11):1636-9

Anxiolytic effects of L-theanine--a component of green tea--when combined with midazolam, in the male Sprague-Dawley rat.

The purpose of the study was to investigate the anxiolytic effects of L-theanine and its potential interaction with the GABAA receptor in Sprague-Dawley rats. L-theanine is a major component of green tea, which has traditionally been used as an herbal remedy in the treatment of many medical conditions, including anxiety. Herbals and supplements and their potential interactions perioperatively are a concern to anesthetists. Fifty-five rats were divided into 5 groups: control (saline); L-theanine (positive control); flumazenil (a known benzodiazepine receptor antagonist) and L-theanine; and midazolam and L-theanine. The behavioral component of anxiety was evaluated using the elevated plus-maze and calculated by the time spent in the open arm of the maze divided by total time in the maze. Data were analyzed using a 2-tailed multivariate analysis of variance and Sheffé posthoc test. The data suggest that L-theanine does not produce anxiolysis by modulation of the GABAA receptor; however, in combination with midazolam, a synergistic or additive effect was demonstrated by decreased anxiety and both fine and basic motor movements. These data may provide direction for further studies examining L-theanine and its effects on anxiety and motor activity.

AANA J. 2009 Dec;77(6):445-9

The combined effects of L-theanine and caffeine on cognitive performance and mood.

The aim of this study was to compare 50 mg caffeine, with and without 100 mg L-theanine, on cognition and mood in healthy volunteers. The effects of these treatments on word recognition, rapid visual information processing, critical flicker fusion threshold, attention switching and mood were compared to placebo in 27 participants. Performance was measured at baseline and again 60 min and 90 min after each treatment (separated by a 7-day washout). Caffeine improved subjective alertness at 60 min and accuracy on the attention-switching task at 90 min. The L-theanine and caffeine combination improved both speed and accuracy of performance of the attention-switching task at 60 min, and reduced susceptibility to distracting information in the memory task at both 60 min and 90 min. These results replicate previous evidence which suggests that L-theanine and caffeine in combination are beneficial for improving performance on cognitively demanding tasks.

Nutr Neurosci. 2008 Aug;11(4):193-8

L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness.

Tea ingredients L-theanine and caffeine have repeatedly been shown to deliver unique cognitive benefits when consumed in combination. The current randomized, placebo-controlled, double-blind, cross-over study compared a combination of L-theanine (97 mg) and caffeine (40 mg) to a placebo on two attention tasks and a self-report questionnaire before, and 10 and 60 min after consumption. The combination of L-theanine and caffeine significantly improved attention on a switch task as compared to the placebo, while subjective alertness and intersensory attention were not improved significantly. The results support previous evidence that L-theanine and caffeine in combination can improve attention.

Appetite. 2010 Apr;54(2):406-9

Mild cognitive impairment can be distinguished from Alzheimer disease and normal aging for clinical trials.

BACKGROUND: Mild cognitive impairment (MCI) represents a transitional state between the cognitive changes of normal aging and very early dementia and is becoming increasingly recognized as a risk factor for Alzheimer disease (AD). The Memory Impairment Study (MIS) is a multicenter clinical trial in patients with MCI designed to evaluate whether vitamin E or donepezil is effective at delaying the time to a clinical diagnosis of AD. OBJECTIVE: To describe the baseline characteristics of patients with MCI recruited for the MIS and compare them with those of elderly controls and patients with AD in another clinical trial. DESIGN: Descriptive and comparative study of patients with MCI participating in a multicenter clinical trial. SETTING: Memory disorder centers in the United States and Canada. PATIENTS: A total of 769 patients with MCI, 107 cognitively normal elderly controls, 122 patients with very mild AD (Clinical Dementia Rating [CDR] 0.5), and 183 patients with mild AD (CDR 1.0) were evaluated. Patients in the MIS met operational criteria for amnestic MCI. Controls were recruited in parallel with the MCI group, underwent the same assessments, and had a CDR of 0. MAIN OUTCOME MEASURES: Clinical, neuropsychologic, functional, neuroimaging, and genetic measures. RESULTS: Mean +/- SD Alzheimer’s Disease Assessment Scale-Cognitive Subscale scores were 5.6 +/- 3.3 for controls, 11.3 +/- 4.4 for patients with MCI, 18.0 +/- 6.2 for the AD CDR 0.5 group, and 25.2 +/- 8.8 for the AD CDR 1.0 group. Compared with controls, patients with MCI were most impaired on memory tasks, with less severe impairments in other cognitive domains. Patients with MCI were more likely than controls but less likely than patients with AD to carry the apolipoprotein E epsilon4 allele. Patients with MCI had hippocampal volumes that were intermediate between those of controls and patients with AD. CONCLUSIONS: Patients with MCI had a predominant memory impairment with relative sparing of other cognitive domains and were intermediate between clinically normal individuals and patients with AD on cognitive and functional ratings. These results demonstrate the successful implementation of operational criteria for this unique group of at-risk patients in a multicenter clinical trial.

Arch Neurol. 2004 Jan;61(1):59-66

Traumatic brain injury and hypopituitarism.

Results of recent and ongoing studies have made it clear that brain injuries like traumatic brain injury (TBI) pose substantial risk to pituitary function, perhaps even greater risk than previously believed. Patients with TBI should be screened both prospectively and retrospectively for isolated, multiple and even total pituitary deficits. It is well known that, patients with “classical” hypopituitarism (due to primary hypothalamic-pituitary pathologies) do benefit from hormonal replacement therapy. It has been suggested that patients with TBI-induced hypopituitarism may benefit with appropriate hormonal replacement receiving replacement therapy such as anti-diuretic hormone (ADH), glucocorticoid and thyroid hormones when needed. Gonadal and recombinant human growth hormone (rhGH) replacement therapy should also be introduced if there are deficiencies demonstrated and even reconfirmed in a second step. The signs and symptoms of post-TBI hypopituitarism may be masked by what has been assumed to be merely the post-traumatic syndrome. By increasing awareness among physicians of the risks of brain injuries-induced endocrinopathies and the need for appropriate endocrinological testing, it may be possible to improve the quality of life and enhance the rehabilitation prospects for these patients. In most instances, these patients are first seen and treated by trauma surgeons and neurosurgeons, and subsequently by rehabilitation physicians; they must be knowledgeable about the risks of hypopituitarism so that they can determine which patients are candidates for screening for hypopituitarism. In addition, endocrinologists and internists must be educated about TBI-induced hypopituitarism and encouraged to actively share their expertise with other physicians.

ScientificWorldJournal. 2005 Sep 15;5:777-81

Traumatic brain injury in children and adolescents: surveillance for pituitary dysfunction.

BACKGROUND: Children who sustain traumatic brain injury (TBI) are at risk for developing hypopituitarism, of which growth hormone deficiency (GHD) is the most common manifestation. OBJECTIVE: To determine the prevalence of GHD and associated features following TBI among children and adolescents. STUDY DESIGN: A total of 32 children and adolescents were recruited from a pediatric TBI clinic. Participants were diagnosed with GHD based on insufficient growth hormone release during both spontaneous overnight testing and following arginine/glucagon administration. RESULTS: GHD was diagnosed in 5/32 participants (16%). Those with GHD exhibited more rapid weight gain following injury than those without GHD and had lower levels of free thyroxine and follicle-stimulating hormone. Males with GHD had lower testosterone levels. CONCLUSIONS: GHD following TBI is common in children and adolescents, underscoring the importance of assessing.

Clin Pediatr (Phila). 2010 Nov;49(11):1044-9

Traumatic brain injury causes long-term reduction in serum growth hormone and persistent astrocytosis in the cortico-hypothalamo-pituitary axis of adult male rats.

In humans, traumatic brain injury (TBI) causes pathological changes in the hypothalamus (HT) and the pituitary. One consequence of TBI is hypopituitarism, with deficiency of single or multiple hormones of the anterior pituitary (AP), including growth hormone (GH). At present no animal model of TBI with ensuing hypopituitarism has been demonstrated. The main objective of this study was to investigate whether cortical contusion injury (CCI) could induce long-term reduction of serum GH in rats. We also tested the hypothesis that TBI to the medial frontal cortex (MFC) would induce inflammatory changes in the HT and AP. METHODS: Nine young adult male rats were given sham surgery (n = 4) or controlled impact contusions (n = 5) of the MFC. Two months post-injury they were killed, trunk blood collected and their brains and AP harvested. GH was measured in serum and AP using ELISA and Western blot respectively. Interleukin-1beta (IL-1beta) and glial fibrillary acidic protein (GFAP) were measured in the cortex (Cx), HT, and AP by Western blot. RESULTS: Lesion rats had significantly (p < 0.05) lower levels of GH in the AP and serum, unaltered serum IGF-1, and significantly (p < 0.05) higher levels of IL-1beta in the Cx and HT and GFAP in the Cx, HT, and AP compared to that of shams. CONCLUSION: CCI leads to a long-term depletion of serum GH in male rats. This chronic change in GH post-TBI is probably the result of systemic and persistent inflammatory changes observed at the level of HT and AP, the mechanism of which is not yet known.

J Neurotrauma. 2009 Aug;26(8):1315-24

GH deficiency as the most common pituitary defect after TBI: clinical implications.

Recent studies have demonstrated that hypopituitarism, and in particular growth hormone deficiency (GHD), is common among survivors of traumatic brain injury (TBI) tested several months or years following head trauma. In addition, it has been shown that post-traumatic neuroendocrine abnormalities occur early and with high frequency. These findings may have significant implications for the recovery and rehabilitation of patients with TBI. The subjects at risk are those who have suffered moderate-to severe head trauma although mild intensity trauma may precede hypopituitarism also. Particular attention should be paid to this problem in children and adolescents. GH deficiency is very common in TBI, particularly isolated GHD. For the assessment of the GH-IGF axis in TBI patients, plasma IGF-I concentrations plus GH response to a provocative test is mandatory. Growth retardation secondary to GHD is a predominant feature of GHD after TBI in children. Clinical features of adult GHD are variable and in most obesity is present. Neuropsychological examinations of patients with TBI show that a significant portion of variables like attention, concentration, learning, memory, conceptual thinking, problem solving and language are impaired in patients with TBI. In the few case reports described, hormone replacement therapy in hormone deficient head-injured patients resulted in major neurobehavioral improvements. Improvements in mental-well being and cognitive function with GH replacement therapy in GHD adults have been reported. The effect of GH replacement in posttraumatic GHD needs to be examined in randomized controlled studies.

Pituitary. 2005;8(3-4):239-43

Effect of growth hormone replacement therapy on cognition after traumatic brain injury.

Traumatic brain injury (TBI) is a major public health issue, and yet medical science has little to offer for the persistent symptoms that prevent many of these individuals from fully re-entering society. Post-traumatic hypopituitarism, and specifically growth hormone deficiency (GHD), has been found in a large percentage of individuals with chronic moderate to severe TBI. Presently, there are no published treatment studies of hormone replacement in this population. In this study, 83 subjects with chronic TBI were screened for hypopituitarism. Forty-two subjects were found to have either GHD or GH insufficiency (GHI), of which 23 agreed to be randomized to either a year of GH replacement or placebo. All subjects completed the study with no untoward side effects from treatment. A battery of neuropsychological tests and functional measures were administered before and after treatment. Improvement was seen on the following tests: Dominant Hand Finger Tapping Test, Wechsler Adult Intelligence Scale III-Information Processing Speed Index, California Verbal Learning Test II, and the Wisconsin Card Sorting Test (executive functioning). The findings of this pilot study provide preliminary evidence suggesting that some of the cognitive impairments observed in persons who are GHD/GHI after TBI may be partially reversible with appropriate GH replacement therapy.

J Neurotrauma. 2010 Sep;27(9):1565-75

Acute and long-term pituitary insufficiency in traumatic brain injury: a prospective single-centre study.

OBJECTIVE: To assess the prevalence of hypopituitarism following traumatic brain injury (TBI), describe the time-course and assess the association with trauma-related parameters and early post-traumatic hormone alterations. DESIGN: A 12-month prospective study. PATIENTS: Forty-six consecutive patients with TBI (mild: N = 22; moderate: N = 9; severe: N = 15). MEASUREMENTS: Baseline and stimulated hormone concentrations were assessed in the early phase (0-12 days post-traumatically), and at 3, 6 and 12 months postinjury. Pituitary tests included the Synacthen-test (acute +6 months) and the insulin tolerance test (ITT) or the GHRH + arginine test if the ITT was contraindicated (3 + 12 months). Insufficiencies were confirmed by retesting. RESULTS: Early post-traumatic hormone alterations mimicking central hypogonadism or hypothyroidism were present in 35 of the 46 (76%) patients. Three months post-traumatically, 6 of the 46 patients failed anterior pituitary testing. At 12 months, one patient had recovered, whereas none developed new insufficiencies. All insufficient patients had GH deficiency (5 out of 46), followed by ACTH- (3 out of 46), TSH- (1 out of 46), LH/FSH- (1 out of 46) and ADH deficiency (1 out of 46). Hypopituitary patients had more frequently been exposed to severe TBI (4 out of 15) than to mild or moderate TBI (1 out of 31) (P = 0.02). Early endocrine alterations including lowered thyroid and gonadal hormones, and increased total cortisol, free cortisol and copeptin were positively associated to TBI severity (P < 0.05), but not to long-term development of hypopituitarism (P > 0.1), although it was indicative in some. CONCLUSION: Long-term hypopituitarism was frequent only in severe TBI. During the 3-12 months follow-up, recovery but no new insufficiencies were recorded, indicating manifest hypothalamic or pituitary damage already a few months postinjury. Very early hormone alterations were not associated to long-term post-traumatic hypopituitarism. Clinicians should, nonetheless, be aware of potential ACTH deficiency in the early post-traumatic period.

Clin Endocrinol (Oxf). 2007 Oct;67(4):598-606

Neuroendocrine dysfunction in the acute phase of traumatic brain injury.

BACKGROUND: Pituitary hormone abnormalities have been reported in up to 50% of survivors of traumatic brain injury (TBI) who were investigated several months or longer following the event. The frequency of pituitary dysfunction in the early post-TBI period is unknown. AIM: To evaluate the prevalence of anterior and posterior pituitary dysfunction in the early phase following TBI. SUBJECTS: Fifty consecutive patients admitted to the neurosurgical unit with severe or moderate TBI [initial Glasgow Coma Scale (GCS) score 3-13], and 31 matched healthy control volunteers were studied. METHODS: The glucagon stimulation test (GST) was performed at a median of 12 days (range 7-20) following TBI. Baseline thyroid function, PRL, IGF-1, gonadotrophins, testosterone or oestradiol, plasma sodium, plasma and urine osmolalities or the standard observed water deprivation test were performed. The control subjects underwent the GST for GH and cortisol responses; other parameters were compared to locally derived reference ranges. RESULTS: Control data indicated that peak serum GH of > 5 ng/ml and cortisol > 450 nmol/l following glucagon stimulation should be taken as normal. Nine TBI patients (18%) had GH response < 5 ng/ml (12 mU/l). Eight patients (16%) had peak cortisol responses < 450 nmol/l. Compared to controls, basal cortisol values were significantly lower in patients with subnormal cortisol responses to glucagon and significantly higher in patients with normal cortisol responses (P < 0.05). GH and cortisol deficiencies were unrelated to patient age, BMI, initial GCS or IGF-1 values (P > 0.05). Forty patients (80%) had gonadotrophin deficiency, with low sex steroid concentrations, which was unrelated to the presence of hyperprolactinaemia. In males there was a positive correlation between serum testosterone concentration and GCS (r = 0.32, P = 0.04). One patient had TSH deficiency. Hyperprolactinaemia was present in 26 patients (52%) and serum PRL levels correlated negatively with the GCS score (r =-0.36, P = 0.011). Thirteen patients (26%) had cranial diabetes insipidus (DI) and seven (14%) had syndrome of inappropriate ADH secretion. CONCLUSION: Our data show that post-traumatic neuroendocrine abnormalities occur early and with high frequency, which may have significant implications for recovery and rehabilitation of TBI patients.

Clin Endocrinol (Oxf). 2004 May;60(5):584-91