Postprandial endothelial dysfunction and CIMT after oral fat challenge in patients with type 2 diabetes mellitus with and without macrovascular disease - A preliminary study

BACKGROUND

Very few studies have reported on association of postprandial lipids and endothelial dysfunction among patients with diabetes. Whether endothelial dysfunction particularly postprandial FMD is worse in patients with T2DM with macrovascular disease compared to those without and whether this difference is related to postprandial hypertriglyceridemia (PPHTg) is unclear. Therefore, present study was aimed to assess the relationship between PPHTg and endothelial function in patients with T2DM with and without macrovascular disease.

METHOD

Endothelial dysfunction by FMD and CIMT were compared in patients with T2DM with and without macrovascular disease (n = 13 each group) and 13 age, sex and BMI matched healthy individuals after an oral fat challenge.

RESULTS

There was significant postprandial deterioration of FMD 4-hr after fat challenge in patients with diabetes (P < 0.001) as well as healthy individuals (P = 0.004). Patients with diabetes with macrovascular disease had significantly lower fasting (5.7 ± 6.1% vs. 22.7 ± 10.0% and vs. 24.7 ± 5.3%) as well as postprandial (4-hr) (3.1 ± 5.0% vs. 15.3 ± 8.1% and vs. 15.4 ± 5.7%) FMD compared to other two groups. Fasting, postprandial as well as change in FMD and CIMT in patients with diabetes correlated significantly with fasting as well as postprandial triglycerides with stronger correlation in those with macrovascular disease.

CONCLUSION

Study found significant endothelial dysfunction by FMD that shows substantial further deterioration postprandially following high fat meal in patients with diabetes with macrovascular disease compared to patients with diabetes without macrovascular disease and healthy individuals. Study also indicates that PPHTg is a contributor to endothelial dysfunction. However, more studies are required to corroborate these findings.

Comparison of antiresorptive effect of hormone therapy and ibandronate in postmenopausal osteoporotic women by assessing type I collagen C-telopeptide levels

OBJECTIVES

The aim of this study is to compare the antiresorptive effect of hormone therapy and oral ibandronate in postmenopausal osteoporotic women by measuring bone mineral density (BMD) and degradation products of C-terminal telopeptide of type I collagen (CTX) using serum crosslaps ELISA.

STUDY DESIGN

The study is a randomized comparative trial.

METHODS

About 60 women with age > 40 years, having either surgical or medical menopause with T- or Z-score below -2.5 SD were included in the study. They were randomized into two groups of 30 each; one group received conventional hormone therapy (group I) and the other group received ibandronate monthly (group II). The treatment was given for 6 months.

RESULTS

The BMD increased from 0.894 g/cm(2) to 0.933 g/cm(2) (p < 0.01) in group I and from 0.865 g/cm(2) to 0.934 g/cm(2) (p < 0.01) in group II. The increase in BMD in group I (4.3%) was less than group II (7.9%) which was significant (p < 0.01). The serum CTX levels also showed significant reduction in both groups after 6 months of therapy; more reduction was seen in group II as compared to group I (41.5% vs. 4.6%, p < 0.01).

CONCLUSION

Ibandronate can be used as a substitute to hormone therapy in women presenting with osteoporosis. Long-term studies are needed to authenticate the observation.

Association between high molecular weight apolipoprotein isoforms and lipoprotein levels in advanced chronic kidney disease and the effect of hemodialysis

To explore the association between high molecular weight apo(a) isoforms and lipoprotein(a) [Lp(a)] in chronic kidney disease (CKD) and the effect of maintenance hemodialysis (MHD), plasma Lp(a) and apo(a) isoforms were determined in age and sex-matched CKD stage 4 and stage 5 patients (repeated after 4 weeks of MHD) and healthy controls (n = 18). Median Lp(a) increased with severity of CKD. Upon HMW apo(a) isoform stratification, Lp(a) in S₂ isoform group was 37.6 mg/dl in CKD stage 4 and 64.0 mg/dl in stage 5 (P < 0.024 and P < 0.001 vs. controls), whereas in S₃ + S₄ group there was no significant increase. Following MHD, Lp(a) also decreased significantly only in the S₂ group. Increase in Lp(a) in CKD patients with HMW apo(a) isoforms is mainly restricted to S₂ isoform group, furthermore, decrease in Lp(a) levels in response to MHD is also seen in this group only.

Post-prandial hypertriglyceridemia in patients with type 2 diabetes mellitus with and without macrovascular disease

OBJECTIVES

To study the postprandial hypertriglyceridemia in patients with type 2 diabetes mellitus with and without macrovascular disease.

METHODS

Postprandial lipids were studied in 13 type 2 diabetic subjects with macrovascular disease (group I), 13 diabetic subjects without macrovascular disease (group II) and 13 age, sex and BMI matched healthy controls (group III) after an oral fat challenge which consisted of meal providing 729 kcal/m2 body surface area with 65.2 g fat.

RESULTS

All the three groups were age, sex and BMI matched. Average duration of diabetes was not significantly different between both the diabetic groups. Waist-hip ratio (WHR) was significantly more in group I and II as compared to group III. Also group I displayed significantly higher WHR than group II. Fasting total cholesterol and LDL levels were significantly higher in group I compared to group III. Fasting HDL was significantly lower in both group I and II vs group III. Fasting TG was not significant between any of the three study groups. Significant postprandial hypertriglyceridemia was observed in group I and group II compared to group III. When area under curves (iAUC) for different lipid parameters were adjusted for their respective fasting values, it was observed that only iAUC TG and iAUC VLDL remained significantly higher in group I and group II as compared to group III. Postprandial triglyceride levels at 6 and 8 hours in group I were significantly higher as compared to group III. Postprandial HDL-C levels at 6 and 8 hours were significantly lower group I and II as compared to group III. Postprandial triglyceride parameters showed significant correlation with fasting triglyceride in group I and II and no significant correlation was found with any of the anthropometric, glycemic and insulin resistance measures.

CONCLUSION

This study finds significant postprandial hypertriglyceridemia and significant delay in postprandialtriglyceride clearance following a standardized fat meal challenge in patients with type 2 diabetes mellitus, particularly those with macrovascular disease. Persistent postprandial hypertriglyceridemia may result in a pro-atherogenic environment leading to atherosclerosis and macrovascular disease in type 2 diabetes subjects.

Glycated hemoglobin--a public health perspective

The burden of diabetes mellitus across the world especially in India is substantial, and much of the morbidity and mortality is due to development of diabetic complications. Control of blood glucose is important to reduce occurrence of these complications. Measurement of glycated haemoglobin values provides valuable information about long term glycemic control, and is recommended for routine monitoring by several clinical guidelines on diabetes. Monitoring and appropriate management have been shown to improve outcomes in patients with diabetes in other parts of the world. However, the adoption of glycated hemoglobin as part of routine monitoring of diabetes patients in India will need to answer issues of availability, affordability and accessibility.

Antioxidant effect of aqueous extract of the bark of Ficus bengalensis in hypercholesterolaemic rabbits

The antioxidant effect of aqueous extract of the bark of Ficus bengalensis has been evaluated in hypercholesterolaemic rabbits. Rabbits were divided into three groups, Group I served as healthy control; groups II and III were made hypercholesterolaemic by feeding cholesterol suspended in groundnut oil (100 mg/kg body weight per day) for 6 weeks. Rabbits of Group III received water extract of the bark of Ficus bengalensis at a dose of 50 mg/kg body weight per day in addition to cholesterol suspended in oil. Feeding cholesterol increased serum cholesterol, triacylglycerol and LDL + VLDL-cholesterol significantly in Group II as compared to Group I (P = 0.001). Treatment with water extract decreased the serum cholesterol level by 59%, triacylglycerol by 54% and LDL + VLDL-cholesterol by 60% in Group III as compared to Group II. In addition, treatment with this extract led to a decrease in lipid peroxidation as evidenced by fall in thiobarbituric acid reactive substances with a corresponding increase in blood glutathione content (P = 0.001). Further, there was significant increase in the activities of antioxidant enzymes; superoxide dismutase (P < 0.001), catalase (P < 0.03), glutathione peroxidase (P = 0.03) and glutathione reductase (P < 0.01); which were depressed in Group II rabbits after cholesterol feeding. Thus, our results show that the water extract of the bark of Ficus bengalensis has significant antioxidant effect, in addition to hypolipidaemic effect.

Lung function tests in electroplaters of East Delhi

The presence of high concentration of metals (Cr, Cd, Co, Ni, Pb, etc.) in the work place environments of various types of industries including electroplating units are well known to influence respiratory system. Pulmonary function tests including forced expiratory capacity (FVC), volumes, mechanics and slow vital capacity (SVC) were studied in 80 males, divided into group I and Group II of 40 each were drawn from electroplating and non-electroplating units, respectively from East Delhi factories. The lung function tests were measured using computerized Spiro-232 of P.K. Morgan, Values of majority of lung function parameters such as FEV1/FVC%, FEF50 FEF75, PIFR, FIF50, MVV and SVC were decreased in electroplaters, perhaps due to the exposure to metals and their lower anthropmetric results as compared with non electoplaters. Where as results of TLC, FRC, RV & RV/ TLC% were higher in electroplaters and this may be attributed to higher values of RV in them as compared with non electroplaters.

Evaluation of Lp[a] and other independent risk factors for CHD in Asian Indians and their USA counterparts

Conventional risk factors for coronary heart disease (CHD) do not completely account for the observed increase in premature CHD in people from the Indian subcontinent or for Asian Indians who have immigrated to the USA. The objective of this study was to determine the effect of immigration to the USA on plasma levels of lipoprotein [a] (Lp[a]) and other independent risk factors for CHD in Asian Indians. Three subject groups were studied: group 1, 57 subjects living in India and diagnosed with CHD (CHD patients); group 2, 46 subjects living in India and showing no symptoms of CHD (control subjects); group 3, 206 Asian Indians living in the USA. Fasting blood samples were drawn to determine plasma levels of triglyceride (TG), total cholesterol (TC), low density lipoprotein [LDL cholesterol (LDL-Chol)], high density lipoprotein [HDL cholesterol (HDL-Chol)], apolipoprotein B-100 (apoB-100), and Lp[a]. Apolipoprotein [a] (apo[a]) size polymorphism was determined by immunoblotting. Plasma TG, apoB-100, and Lp[a] concentrations were higher in CHD patients than in control and USA groups. CHD patients had higher levels of TC and LDL-Chol and lower HDL-Chol than control subjects. However, the USA population had higher levels of TC, LDL-Chol, and apoB-100 and lower HDL-Chol than control subjects. Plasma Lp[a] levels were inversely correlated with the relative molecular weight of the more abundant of each subject's two apo[a] isoforms (MAI), and CHD patients showed higher frequencies of lower relative molecular weights among MAI. Our observed changes in lipid profiles suggest that immigrating to the USA may place Asian Indians at increased risk for CHD. This study suggests that elevated plasma Lp[a] confers genetic predisposition to CHD in Asian Indians, and nutritional and environmental factors further increase the risk of CHD. This is the first report implicating MAI size as a predictor for development of premature CHD in Asian Indians. Including plasma Lp[a] concentration and apo[a] phenotype in screening procedures may permit early detection and preventive treatment of CHD in this population.

Lipoprotein(a) as an independent risk factor for coronary artery disease in patients below 40 years of age

Coronary artery disease has assumed alarming proportions in Indians and often affects people at younger age. Traditional risk factors fail to explain the high incidence of disease. Although lipoprotein(a) has been shown to be a powerful risk factor for atherosclerosis, there is very limited data with regard to its significance in premature coronary artery disease. The present study was therefore undertaken to assess lipoprotein(a) levels and its role as a marker of coronary artery disease in patients below the age of 40 years. Lipid profile and lipoprotein(a) levels were estimated in 50 patients of angiographically proven coronary artery disease and an equal number of age-matched healthy controls. There was no significant difference in the family history of coronary artery disease, body mass index and waist-hip ratio between the two groups. Total plasma cholesterol, triglyceride and LDL-cholesterol levels were significantly higher and HDL-cholesterol significantly lower in patients as compared to controls. In patients of coronary artery disease, mean lipoprotein(a) levels, measured by ELISA method, were 35.0 +/- 32.4 mg/dL and the median was 26.7 mg/dL. These values were significantly higher than the mean of 20.3 +/- 17.0 mg/dL (p < 0.002) and the median of 13.8 mg/dL (p < 0.015) in controls. Multiple regression analysis, to assess the influence of various risk factors, showed that low HDL-cholesterol (odds ratio 4.62, 95% CI 1.84-11.60; p < 0.015) and elevated lipoprotein(a) levels (odds ratio 3.06, 95% CI 1.24-7.55; p < 0.001) were independent risk factors, whereas high total cholesterol and triglyceride levels did not have any independent influence on premature coronary artery disease. Our data thus suggest that lipoprotein (a) levels are elevated and constitute an independent risk factor in patients with premature coronary artery disease below 40 years of age.

Correlation between blood antioxidant levels and lipid peroxidation in rheumatoid arthritis

OBJECTIVES

To investigate the relationship between lipid peroxidation and certain antioxidant parameters in the blood of rheumatoid arthritis patients.

METHODS AND RESULTS

In the present study, significantly increased lipid peroxidation, measured as malondialdehyde (MDA), was demonstrated in the plasma of rheumatoid arthritis patients (p < 0.01). The activities of erythrocyte antioxidant enzymes, superoxide dismutase and catalase remained unaltered. However, erythrocyte glutathione and plasma ceruloplasmin levels were significantly higher in patients (p < 0.001). Moreover, a positive correlation was also observed between these two parameters and MDA levels in the patient group but not in controls. Interestingly, a significant positive correlation also existed between red cell glutathione and plasma ceruloplasmin levels.

CONCLUSION

These results suggest that increased oxidant stress present in rheumatoid arthritis may lead to compensatory changes in the levels of some antioxidants, viz. glutathione and ceruloplasmin. These changes, in turn, may provide additional protection against lipid peroxidation in rheumatoid arthritis.