Transient Decrease in Circulatory Testosterone and Homocysteine Precedes the Development of Metabolic Syndrome Features in Fructose-Fed Sprague Dawley Rats.

Background. Increased fructose consumption is linked to the development of metabolic syndrome (MS). Here we investigated the time course of development of MS features in high-fructose-fed Sprague Dawley rats along with circulatory testosterone and homocysteine levels. Methods. Rats were divided into control and experimental groups and fed with diets containing 54.5% starch and fructose, respectively, for 4, 12, and 24 weeks. Plasma testosterone and homocysteine levels were measured along with insulin, glucose, and lipids. Body composition, insulin resistance, and hepatic lipids were measured. Results. Increase in hepatic triglyceride content was first observed in metabolic disturbance followed by hypertriglyceridemia and systemic insulin resistance in fructose-fed rats. Hepatic lipids were increased in time-dependent manner by fructose-feeding starting from 4 weeks, but circulatory triglyceride levels were increased after 12 weeks. Fasting insulin and Homeostatis Model Assessment of Insulin Resistance (HOMA-IR) were increased after 12 weeks of fructose-feeding. Decreased visceral adiposity, circulatory testosterone, and homocysteine levels were observed after 4 weeks of fructose-feeding, which were normalized at 12 and 24 weeks. Conclusions. We conclude that transient decrease in circulatory testosterone and homocysteine levels and increased hepatic triglyceride content are the earliest metabolic disturbances that preceded hypertriglyceridemia and insulin resistance in fructose-fed SD rats.

Status of B-vitamins and homocysteine in diabetic retinopathy: association with vitamin-B12 deficiency and hyperhomocysteinemia.

Diabetic retinopathy (DR) is a common cause of blindness. Although many studies have indicated an association between homocysteine and DR, the results so far have been equivocal. Amongst the many determinants of homocysteine, B-vitamin status was shown to be a major confounding factor, yet very little is known about its relationship to DR. In the present study, we, therefore, investigated the status of B-vitamins and homocysteine in DR. A cross-sectional case-control study was conducted with 100 normal control (CN) subjects and 300 subjects with type-2 diabetes (T2D). Of the 300 subjects with T2D, 200 had retinopathy (DR) and 100 did not (DNR). After a complete ophthalmic examination including fundus fluorescein angiography, the clinical profile and the blood levels of all B-vitamins and homocysteine were analyzed. While mean plasma homocysteine levels were found to be higher in T2D patients compared with CN subjects, homocysteine levels were particularly high in the DR group. There were no group differences in the blood levels of vitamins B1 and B2. Although the plasma vitamin-B6 and folic acid levels were significantly lower in the DNR and DR groups compared with the CN group, there were no significant differences between the diabetes groups. Interestingly, plasma vitamin-B12 levels were found to be significantly lower in the diabetes groups compared with the CN group; further, the levels were significantly lower in the DR group compared with the DNR group. Higher homocysteine levels were significantly associated with lower vitamin-B12 and folic acid but not with other B-vitamins. Additionally, hyperhomocysteinemia and vitamin-B12 deficiency did not seem to be related to subjects' age, body mass index, or duration of diabetes. These results thus suggest a possible association between vitamin-B12 deficiency and hyperhomocysteinemia in DR. Further, the data indicate that vitamin-B12 deficiency could be an independent risk factor for DR.

Gender-related differences in the relationship between plasma homocysteine, anthropometric and conventional biochemical coronary heart disease risk factors in middle-aged Indians.

BACKGROUND/OBJECTIVE: Gender-related differences in anthropometric measures [body mass index (BMI) and waist circumference (WC)] and other coronary heart disease (CHD) risk factors have been reported in other ethnics. However, information available on middle aged healthy Indians are scanty. The aim of our present study is to determine plasma total homocysteine (tHcy), anthropometric measures (BMI and WC) and conventional biochemical CHD risk factors, and to examine their relationship in healthy middle-aged men and women. METHODS: Fifty-two middle aged (40-59 years) apparently healthy volunteers (29 men and 23 women) were recruited from the staff of the National Institute of Nutrition at Hyderabad. Subjects were screened for plasma tHcy concentrations, lipid profile and blood pressure. Anthropometric Indices (BMI, WC) were measured as per standard protocols. Data on education, income, diet (vegetarians vs. omnivores) and lifestyle factors such as smoking, alcohol consumption and exercise were recorded. RESULTS: At similar age and BMI, men had higher WCs (mean +/- SD, 91.2 +/- 5.44 vs. 78.9 +/- 7.62 cm, p < 0.001) than women. Plasma tHcy concentrations (17.9 +/- 9.88 vs. 8.2 +/- 1.90 micromol/l, p < 0.001) were also higher in men than in women. Among men, vegetarian men had significantly higher plasma tHcy than omnivorous men (median 22.80 vs. 9.85 micromol/l, p < 0.05). Plasma tHcy concentrations were comparable between vegetarian and omnivorous women. Of known conventional CHD risk factors, blood pressure, total cholesterol and triglycerides were also significantly (p < 0.05) higher in men than in women. A significant positive correlation was found between plasma tHcy and WC in men only (r = 0.484, p < 0.01). In women, in turn, plasma tHcy was positively correlated with low-density-lipoprotein cholesterol (r = 0.567, p < 0.01). CONCLUSIONS: This study on apparently healthy Indians confirms the known associations between gender and conventional CHD risk factors, while diet (vegetarian vs. omnivorous) had no influence on CHD risk factors with the exception of tHcy in men.