Atherosclerosis, the cholesterol deposition in and around cells of the intimal layer of the aorta, has been recognized as one of the main causative factors for cardiovascular diseases. Intensive research has been carried out throughout the world but the precise atherogenesis has yet to be fully understood, though hypercholesterolaemia is considered to be the prime risk factor. The aim of the study was to evaluate the effect of high cholesterol diet consumption on the formation of atherosclerosis in vivo. Three groups of adultWhite New Zealand male rabbits (six animals per group) were used in this study. Except for one group which acted as a control (K), the other two groups were given 1% and 2% high cholesterol diet respectively for 10 weeks. At the end of the experiment, blood samples were taken from the marginal ear vein for plasma cholesterol estimation. The animals were sacrificed and the aorta was excised for histomorphometric analysis. The result shows that despite no significant differences in plasma cholesterol levels being observed between the groups treated with 1% and 2% cholesterol, high cholesterol consumption was able to induce hypercholesterolaemia significantly (p
Two new vascular health markers which are derived from finger
photoplethysmography (PPG) waveform have been introduced based on Malaysian
population, namely PPG fitness index (PPGF) and vascular risk prediction index
(VRPI). The objectives of this study were to investigate the associations between
PPGF and other cardiovascular disease (CVD) markers such as carotid femoral pulse
wave velocity (PWVCF), to compare PPGF between those with and without CVD risk
factors and to determine the sensitivity of VRPI in identifying young subjects with
CVD risk factors. A total of 114 men age 20 to 40 yrs with and without CVD risk
factors were recruited. Risk factors included hypertension, smoking, dyslipidemia,
abdominal obesity and family history of premature CVD. Subjects were divided
into healthy, those with one risk factor and those with at least two risk factors. Their
weight, height, peripheral and central blood pressure (BP), PWVCF and PPGF were
measured and the sensitivity of VRPI in predicting subjects with CVD risk factor was
calculated. Data was analyzed via SPSS version 15 and p < 0.05 was considered
significant. The mean age of the subjects was 28.94 ± 4.86 yrs. No differences in
PPGF was observed between groups (p > 0.05). The independent variables for
PPGF were forward pressure (Beta = 0.35, p < 0.01), PWVCF (Beta = -0.26, p < 0.01),
systolic BP (Beta = -0.26, p = 0.04) and height (Beta = 0.24, p < 0.01). The sensitivity
of VRPI was 82.02%. In conclusion, PPGF was correlated to PWVCF and may be a
potential marker of arterial stiffness. In addition, VRPI is sensitive to be used as an
early screening of CVD risk factors.
The aim of this study was to investigate the effect of altered thyroid status on 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD type 1) and type 2 (11beta-HSD type 2) bioactivity in rat kidney and colon. Male Sprague-Dawley rats (250 g) were treated with either L-thyroxine (T4) or propylthiouracil (PTU) for 4 weeks. Blood were then analysed for serum thyroxine, sodium (Na+) and potassium (K+). The kidneys and colon were assayed for 11beta-HSD type 1 and 11beta-HSD type 2 bioactivity. In T4 treated rats the serum thyroxine was significantly elevated (p<0.05) whilst PTU decreased serum thyroxine significantly (p<0.001) compared to controls. Serum Na+ and K+ were within normal limits. There were no significant changes in 11beta-HSD type 1 bioactivity in both treatment groups compared to controls. However, the 11beta-HSD type 2 bioactivity in rats given thyroxine was significantly higher in the colon (p<0.003) compared to controls. We conclude that altered thyroid status had no effect on 11beta-HSD type 1 bioactivity but 11beta-HSD type 2 bioactivity was elevated in the colon of rats given supplementary thyroxine.
The fruit extract of Garcinia atroviridis (G. atroviridis) contains hydroxycitric acid and flavonoids, which have been reported to have a hypolipidaemic property. This extract with solvent methanol was used to investigate its effects on serum lipid profiles of guinea pigs fed a high cholesterol diet.
Herbs with antidiabetic activity have a potential role to play. Herbal medicines have been widely used in South East Asia because of lesser side effects and cost effectiveness. The main aim of this review article was to disseminate important information regarding the use of herbal products in oxidative stress involved in diseases like diabetes mellitus. The article highlights some of the traditional medicinal plants which have been widely used in South East Asia with special emphasis on Piper sarmentosum. Piper sarmentosum have been reported to possess varying degree of hypoglycemic, antidiabetic and other additional properties. The antioxidant properties of the herbs may be effective in controlling the oxidative damage produced during diabetes mellitus. The review article highlights the positive role of traditional herbs towards diabetes mellitus and also describes its complications.
1. The mean levels of lipid peroxidation products, namely conjugated diene and malonaldehyde, were increased in the soleus muscles of hyperthyroid cats, while the mean glutathione peroxidase activity was decreased. No corresponding similar changes were noted in the fast extensor digitorum longus muscles and serum. 2. Propranolol administration prevented the increase in conjugated diene level in the soleus muscles of hyperthyroid cat but not the malonaldehyde level. It also prevented the reduction in glutathione peroxidase activity in the slow oxidative soleus muscles of hyperthyroid cats. 3. Maximal twitch tension, subtetanic tension and maximum tetanic tension of soleus and EDL muscles were reduced in hyperthyroid cats. Propranolol administration for 5 weeks to hyperthyroid cats did not prevent the reduction in tension of contractions of these muscles. 4. It is suggested that lipid peroxidation might not be responsible for the myopathy in hyperthyroidism and propranolol administration does not improve skeletal muscle function in hyperthyroid animals.
The soleus muscles of hyperthyroid rats were used to investigate the effect of palm olein oil and soya bean oil on the production of lipid peroxidation products. It was found that palm olein oil but not soya bean oil significantly decreased malonaldehyde and conjugated diene levels of the soleus muscles of hyperthyroid rats. These findings suggest that palm olein per se produces less lipid peroxidation products than soya bean oil. Such an assay method gives a composite net picture of the propensity of an oil to produce lipid peroxidation products.
Endothelial cell death due to increased reactive oxygen species (ROS) may contribute to the initial endothelial injury, which promotes atherosclerotic lesion formation. Piper sarmentosum (PS), a natural product, has been shown to have an antioxidant property, which is hypothesized to inhibit production of ROS and prevent cell injury. Thus, the present study was designed to determine the effects of PS on the hydrogen peroxide (H(2)O(2))-induced oxidative cell damage in cultured human umbilical vein endothelial cells (HUVECs). In this experiment, HUVECs were obtained by collagenase perfusion of the large vein in the umbilical cord and cultured in medium M200 supplemented with low serum growth supplementation (LSGS). HUVECs were treated with various concentrations of H(2)O(2) (0-1000 micromol/L) and it was observed that 180 micromol/L H(2)O(2) reduced cell viability by 50% as denoted by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Using the above concentration as the positive control, the H(2)O(2)-induced HUVECs were concomitantly treated with various concentrations (100, 150, 250 and 300 microg/ml) of three different extracts (aqueous, methanol and hexane) of PS. Malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) levels showed a significant increase (P<0.05) in HUVECs compared to the negative control. However, PS extracts showed a protective effect on HUVECs from H(2)O(2)-induced cell apoptosis with a significant reduction in MDA, SOD, CAT and GPX levels (P<0.05). Furthermore, PS had exhibited ferric reducing antioxidant power with its high phenolic content. Hence, it was concluded that PS plays a beneficial role in reducing oxidative stress in H(2)O(2)-induced HUVECs.
There is accumulating data demonstrated hypercholesterolemia and oxidative stress play an important role in the development of atherosclerosis. In the present study, a protective activity of alpha-lipoic acid; a metabolic antioxidant in hypercholesterolemic-induced animals was investigated. Eighteen adult male New Zealand White (NZW) rabbit were segregated into three groups labelled as group K, AT and ALA (n=6). While group K was fed with normal chow and acted as a control, the rest fed with 100 g/head/day with 1% high cholesterol diet to induce hypercholesterolemia. 4.2 mg/body weight of alpha lipoic acid was supplemented daily to the ALA group. Drinking water was given ad-libitum. The study was designed for 10 weeks. Blood sampling was taken from the ear lobe vein at the beginning of the study, week 5 and week 10 and plasma was prepared for lipid profile estimation and microsomal lipid peroxidation index indicated with malondialdehyde (MDA) formation. Animals were sacrificed at the end of the study and the aortas were excised for intimal lesion analysis. The results showed a significant reduction of lipid peroxidation index indicated with low MDA level (p<0.05) in ALA group compared to that of the AT group. The blood total cholesterol (TCHOL) and low density lipoprotein (LDL) levels were found to be significantly low in ALA group compared to that of the AT group (p<0.05). Histomorphometric intimal lesion analysis of the aorta showing less of atheromatous plaque formation in alpha lipoic acid supplemented group (p<0.05) compared to that of AT group. These findings suggested that apart from its antioxidant activity, alpha lipoic acid may also posses a lipid lowering effect indicated with low plasma TCHOL and LDL levels and reduced the athero-lesion formation in rabbits fed a high cholesterol diet.