Purushothaman Pavithran

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.

Heart rate variability in middle-aged men with new-onset hypertension.

Background: It has been well established that hypertension is associated with autonomic dysregulation. Studies investigating HRV have established that hypertension is characterized by sympathetic overactivity and or attenuation of parasympathetic modulation of the heart.

Effect of antihypertensive therapy on serum lipids in newly diagnosed essential hypertensive men.

The effect of antihypertensives on serum lipids in newly diagnosed male essential hypertensive patients was studied. The participants (n = 99) were randomly allocated to receive amlodipine, atenolol, enalapril, hydrochlorothiazide, and a combination of amlodipine and atenolol. Lipid parameters were estimated before and after 8 weeks of therapy. The atenolol and thiazide group showed a significant increase in triglycerides (TGs) and very-low-density lipoprotein cholesterol (VLDL-C). High-density lipoprotein cholesterol (HDL-C) and HDL-C to low-density lipoprotein cholesterol (LDL-C) ratio were significantly increased and TC to HDL-C ratio was significantly decreased in the amlodipine and amlodipine— atenolol combination groups. In the enalapril group, we found a significant reduction in TC, TGs, VLDL-C, nonHDL-C, and TG to HDL-C ratio after treatment. It can be concluded from the present study that some drugs have beneficial effects on the lipid status, whereas others adversely affect the lipid status in hypertension.

Effect of antihypertensive drug therapy on short-term heart rate variability in newly diagnosed essential hypertension.

1. Abnormalities of cardiac autonomic regulation are a potential mechanism for morbidity despite blood pressure (BP) lowering in hypertension. Analysis of short‐term (5 min) heart rate variability (HRV) provides a non‐invasive probe of autonomic regulation of sino‐atrial (SA) node automaticity.

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.

Sex Differences in Short-Term Heart Rate Variability in Patients With Newly Diagnosed Essential Hypertension

The authors report the results of the analysis of heart rate variability (HRV) indices during 5 minutes of supine rest and 5 minutes of standing and conventional indices of autonomic function in 69 men and 51 women with untreated newly diagnosed hypertension matched for body mass index and resting blood pressure. Mean RR interval, standard deviation of normal‐to‐normal RR intervals, low‐frequency RR spectral power, HRV during deep breathing at 6 breaths per minute, and the 30:15 ratio (maximum RR interval 30th beat/minimum RR interval 15th beat) were significantly lower in women (P=.01, .02, .001, .04, .01, respectively) compared with men. Low frequency RR in normalized units was lower in women in the supine position alone (P=.03). HRV was significantly lower in women with untreated newly diagnosed hypertension compared with men. The authors interpret these results as indicating an increase in baseline cardiac sympathovagal balance in female hypertensive patients.

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.