Cardioprotective effects of cysteine alone or in combination with taurine in diabetes.

This study was undertaken to examine the effects of dietary supplementation of cysteine and taurine in rats with diabetes induced with streptozotocin (STZ, 65 mg/kg body weight). Experimental animals were treated orally (by gavage) with cysteine (200 mg/kg) and taurine (400 mg/kg), alone or in combination, daily for 8 weeks. In one group, rats were also pretreated 3 weeks before the induction of diabetes (prevention arm) whereas in the other, the treatment was started 3 days after the induction of diabetes (reversal arm). Diabetes increased heart weight/body weight (HW/BW) ratio, plasma glucose, triglyceride and cholesterol levels as well as depressed heart rate (HR), blood pressure, left ventricular systolic pressure (LVSP), rate of contraction (+dP/dt), rate of relaxation (-dP/dt), fractional shortening (FS) and cardiac output (CO). The left ventricular internal diameter in systole (LViDs) was increased whereas that in diastole (LViDd) was decreased. In the prevention arm, treatment of the diabetic animals with cysteine or taurine decreased HW/BW ratio and improved HR, FS, +dP/dt and -dP/dt, as well as normalized LViDs, without altering the increase in glucose level. Cysteine decreased plasma triglyceride and cholesterol levels and improved LVSP whereas CO was improved by taurine. In the reversal arm, cysteine alone or with taurine did not correct the changes in hemodynamic parameters, FS and plasma triglycerides. Diabetes-induced cardiac dysfunction and increases in plasma triglycerides can be prevented, but not reversed, by dietary cysteine alone or in combination with taurine.

The effect of dietary hempseed on atherogenesis and contractile function in aortae from hypercholesterolemic rabbits.

UNLABELLED: Hempseed contains a unique combination of both omega-3 and omega-6 polyunsaturated fatty acids. In other studies, supplementation of the diet with selected polyunsaturated fatty acids has induced significant, beneficial cardiovascular effects. The purpose of the present study is to determine if hempseed ingestion over an 8-week period may provide protection to rabbits against the deleterious effects associated with dietary cholesterol supplementation. METHODS: Male albino New Zealand White rabbits were randomly divided into one of six groups: the control diet (RG), the control diet then supplemented with (wt/wt) 5% coconut oil (CO), or 10% hempseed (HP), or 0.5% cholesterol (OL), or with both 10% hempseed and 0.5% cholesterol (OLHP) or with 10% hempseed that was partially delipidated (SC). Each day the rabbits were fed 125 grams of the appropriate diet over an 8-week period. Fatty acid analysis of tissue and diets was determined using gas chromatography. Vascular function testing of aortic rings was done in order to assess the response of the tissue to both contraction and relaxation stimuli. Aortic atherosclerotic plaque was quantified. RESULTS: Cholesterol supplementation to the diet induced significant aortic plaque development. Dietary hempseed did not generate protection. The aorta obtained from rabbits fed the cholesterol-supplemented chow also exhibited defects in their contractile responses to KCl and norepinephrine and in relaxation to sodium nitroprusside (SNP).The addition of hempseed to this diet did not generate any improvement in contractile responses but had a modest protective effect on the cholesterol-induced defects in SNP-induced relaxation. CONCLUSIONS: Our data demonstrate that dietary hempseed provides mildly beneficial effects against contractile dysfunction associated with atherosclerotic vessels in the cholesterol-fed rabbit.

Bioavailability of alpha-linolenic acid from flaxseed diets as a function of the age of the subject.

BACKGROUND: Dietary flaxseed may have beneficial cardiovascular effects. An aged population has a higher incidence of cardiovascular disease, but they may react differently to flaxseed in the diet. OBJECTIVE: To investigate the response, over a period of 4 weeks, of subjects aged 18-29 or 45-69 years to a diet containing the same amount of alpha-linolenic acid (ALA) (6 g) introduced in the form of ground flaxseed (30 g) or flaxseed oil. RESULTS: All subjects who received flaxseed oil showed a significant increase in plasma ALA and eicosapentaenoic acid (EPA) concentrations over the course of this study. Subjects who received ground flaxseed in the 18-29-year-old group showed a statistically significant increase in their plasma ALA levels, and although there was a trend in the same direction for the 45-69-year-old subjects, this did not achieve statistical significance. The diets induced no major changes in platelet aggregation, plasma total cholesterol, low-density lipoprotein or high-density lipoprotein cholesterol levels in any of the groups. Younger subjects showed a decrease in triglyceride (TG) values compared with older subjects. There were no significant side effects that caused compliancy issues. CONCLUSION: Subject age does not seem to be a major determining factor in influencing ALA absorption from a flaxseed-supplemented diet nor in the metabolism of ALA to EPA in the groups fed flaxseed oil. Concerns about side effects in older subjects administered a higher fiber load in a flaxseed-supplemented diet are not justified. However, younger but not older subjects showed a beneficial decrease in circulating TGs due to flaxseed supplementation.