V. Sathiyapriya

Short-Term Heart Variability and Oxidative Stress in Newly Diagnosed Essential Hypertension

We sought to evaluate oxidative stress parameters like malondialdehyde, total antioxidant status, and time, frequency domain heart rate variability indices in newly diagnosed untreated hypertension. We also sought to study the correlation between heart rate variability and oxidative stress parameters in normotensive and newly diagnosed untreated essential hypertensives. Fourteen normotensive males and 36 newly diagnosed male hypertensives were enrolled for the study. Malondialdehyde, total antioxidant status, and heart rate variability in the frequency and time domain were studied in the hypertensive and normotensive group. Malondialdehyde was significantly higher in the hypertensive group, whereas total antioxidant status was significantly higher in the control group. SDNN, RR triangular index, RMSSD, log 10 low-frequency power, log 10 high-frequency power, log 10 total power, and heart rate variability during deep breathing test was significantly lower in hypertensive patients compared to normotensive controls. SDNN, RMSSD, high-frequency power, and high-frequency power normalized had significant negative correlation with malondialdehyde. Low-frequency power normalized positively correlated with malondialdehyde. Total antioxidant status had a significant negative correlation with blood pressure. The study gives further evidence for a decreased heart rate variability and elevated oxidative stress in hypertension.

Association between Protein Bound Sialic Acid and High Sensitivity C-Reactive Protein in Prehypertension : A Possible Indication of Underlying Cardiovascular Risk

The global burden posed by cardiovascular disease due to a rising incidence of known risk factors like essential hypertension underlines an urgent need to identify other potential risk factors like dyslipidemia, elevated levels of high-sensitivity CRP (hsCRP), Apo-B, and sialic acid in prehypertensive subjects. This study sought to examine the possible alteration in the levels of hsCRP, plasma protein bound sialic acid, and other lipid risk factors and the possible interactions among these parameters in prehypertensive subjects. Forty prehypertensive and 34 normotensive male subjects were enrolled in the study. Lipid profile, hsCRP, Apo-B, sialic acid, and lipid risk ratios were estimated in both the groups. There was no significant difference between fasting glucose and BMI in either group. The levels of total cholesterol, triglycerides, direct LDL-cholesterol, non-HDL cholesterol, and Apo-B were significantly increased in prehypertensive subjects compared with controls. The risk ratios calculated as direct LDL-cholesterol/Apo-B, total cholesterol/HDL-cholesterol, non-HDL-cholesterol/HDL-cholesterol were significantly elevated in prehypertensive subjects. There was also a significant increase in hsCRP and protein bound sialic acid in prehypertensive subjects in comparison with normotensive subjects. Correlation analysis revealed a significant association between the protein bound sialic acid with hsCRP, LDL cholesterol, and LDL-C/Apo-B. The findings of the present study suggest that in prehypertension, there is an association between protein bound sialic acid and hsCRP that reflects the clustering of cardiovascular risk factors in these subjects.

Insulin resistance and enhanced protein glycation in men with prehypertension.

Abstract Background: Insulin resistance and hyperinsulinemia have been reported among patients with hypertension. However, little is known about insulin sensitivity in subjects with prehypertension. The aim of this study was to assess whether the metabolic characteristics of insulin resistance syndrome are present in prehypertensive subjects. Methods: Plasma fasting glucose, lipid profile, glycated hemoglobin, fructosamine and insulin concentrations were evaluated in 35 prehypertensive subjects and in 30 healthy controls. Results: Prehypertensive subjects had significantly higher levels of plasma insulin and triglycerides compared with normotensive subjects. The level of high-density lipoprotein cholesterol was significantly lower in prehypertensive subjects compared with controls. There was no significant difference in total cholesterol and low-density lipoprotein cholesterol levels. The levels of glycated hemoglobin and fructosamine were also significantly higher in prehypertensive subjects compared with controls. Plasma insulin levels were positively correlated with systolic and diastolic blood pressure in prehypertensive subjects. Similarly, plasma insulin was significantly positively correlated with triglyceride and negatively correlated with high-density lipoprotein cholesterol. Conclusions: The present study indicates that prehypertensive non-diabetic subjects have higher insulin resistance and protein glycation compared to normotensive subjects, which may contribute to the pathogenesis of prehypertension. Clin Chem Lab Med 2006;44:1457–61.

Increased glycation of hemoglobin and plasma proteins in normotensive, non-diabetic obese Indian subjects: putative role of lipid peroxides

Abstract Background: Glycation and lipid peroxidation are spontaneous reactions believed to contribute to the pathogenesis of many clinical disorders. The purpose of the present study was to evaluate the levels of lipid peroxides and glycated proteins in normotensive, non-diabetic obese Indian subjects and to assess possible associations between them. Methods: A total of 28 obese male subjects and 20 non-obese subjects were included in the present study. Whole blood glycated hemoglobin, plasma lipid peroxides and fructosamine levels were estimated in both groups. Results: Lipid peroxides, glycated hemoglobin and fructosamine levels were significantly higher in obese subjects in comparison with non-obese subjects. We also found a significant association between malondialdehyde and body mass index (r=0.424, p=0.025). Partial correlation analysis revealed that malondialdehyde was significantly correlated with glycated hemoglobin (r=0.590, p=0.01) and fructosamine (r=0.442, p=0.021) after controlling for glucose. Conclusions: Increased glycation of proteins was found in normotensive, non-diabetic obese Indian subjects. These data also support the premise that lipid peroxides per se play a role in the glycation of hemoglobin and plasma proteins. Clin Chem Lab Med 2007;45:996–9.

Association Between Protein-Bound Sialic Acid and High-Sensitivity C-Reactive Protein in Essential Hypertension: A Possible Indication of Underlying Cardiovascular Risk

The aim of this study was to examine the possible alteration in the levels of C-reactive protein, protein-bound sialic acid, and other lipid risk factors in newly diagnosed essential hypertensive subjects. In all, 56 hypertensive and 33 normotensive male subjects were enrolled in the study. Lipid profile, C-reactive protein, apolipoprotein-B, and protein-bound sialic acid were estimated in both the groups. Total cholesterol, triglyceride, low-density lipoprotein—cholesterol, C-reactive protein, apolipoprotein-B, and protein-bound sialic acid were significantly increased in patients with essential hypertension. Correlation analysis revealed a significant association between the protein-bound sialic acid with mean arterial pressure, C-reactive protein, and low-density lipoprotein—cholesterol. The findings of the present study suggest that in essential hypertension there is an association between protein-bound sialic acid and C-reactive protein, which reflects the clustering of cardiovascular risk factors in these patients.

Elevated Glutathione Peroxidase in Newly Diagnosed Hypertension: Its Relation to Insulin Resistance

Several studies have reported that insulin resistance and compensatory hyperinsulinemia often coexist with hypertension. Increased activity of glutathione peroxidase has been reported in patients with essential hypertension. Recently, overexpression of glutathione peroxidase has also been linked to the etiology of insulin resistance. The aim of this study was to determine the possible relation between the activity of glutathione peroxidase and insulin resistance status in essential hypertensive patients. A case–control study was performed on 35 hypertensive patients and 30 control subjects. The levels of insulin and insulin resistance as measured by the homeostasis model assessment insulin resistance index (HOMA-IR) and glutathione peroxidase were significantly increased in hypertensive patients compared with control subjects. In this study, a direct association was observed between glutathione peroxidase with HOMA-IR and insulin levels in essential hypertensive subjects. In conclusion, our results suggest that increased glutathione peroxidase can be one of the detrimental factors in contributing to insulin resistance in essential hypertensive subjects.