Urinary albumin excretion and heart rate variability in obese women

Interplay of vitamin D and nitric oxide in post-menopausal knee osteoarthritis

AIM

Mounting evidence has presented nitric oxide (NO) and vitamin D (vitD) as having independently complex roles in osteoarthritis (OA). However, a mechanistic or an observational connection between them has never been investigated in the disease. This study investigates the correlation between circulating 25-hydroxyvitamin D [25(OH)D] and total NO as nitrate/nitrite (NO x ) in patients with knee OA.

METHODS

The recruited subjects comprised 36 post-menopausal women with knee OA, ages 50-60 years, as well as 10 healthy males, 20-30 years of age. 25(OH)D and NO x levels were determined using high-performance liquid chromatography and spectrophotometrically using Griess reaction, respectively.

RESULTS

The mean (SEM) 25(OH)D and NO x concentrations of OA patients were 25.0 (1.6) ng/mL and 32.45 (2.18) μM, respectively, and 35.4 (2.1) ng/mL and 25.49 (2.23) μM, respectively, for controls. Comparison of mean 25(OH)D and NO x concentrations of OA patients and controls yielded significant results (P = 0.001 and 0.034, respectively). NO notably decreased with decreasing 25(OH)D concentration in patients. However, significant results in terms of mean NO x concentration were observed in the comparison of normal and deficient vitD OA groups (P = 0.048).

CONCLUSION

Results suggest that vitD increases NO production and inducible NO synthase expression in osteoarthritic chondrocytes possibly leading to a protective effect.

Epidemiological evidence of altered cardiac autonomic function in overweight but not underweight subjects

BACKGROUND

Little is known about the altered cardiac autonomic function (CAF) across different levels of body mass index (BMI), including underweight, normal weight, overweight and obesity. This study provides a thorough analysis to clarify the CAF change in subjects with underweight, overweight and obesity.

METHODS

According to the World Health Organization (WHO) Asia-Pacific BMI cutoffs, a total of 1437 participants were classified as underweight (n=74), normal weight (n=588), overweight (n=313), obesity I (n=390) and obesity II (n=72). CAF was determined by standard deviation of normal-to-normal (SDNN) intervals or RR intervals, power spectrum in low (LF) and high frequency (HF) (LF, 0.04-0.15 Hz; HF, 0.15-0.40 Hz), and LF/HF ratio at supine for 5 min, the ratio between the 30th and the 15th RR interval after standing from the supine position (30/15 ratio) and the average heart-rate change while taking six deep breaths in 1 min (HR(DB)).

RESULTS

There were significant differences in age, gender, socioeconomic status, blood pressure, HOMA insulin resistance index, fasting glucose, cholesterol, triglyceride and high-density lipoprotein (HDL)-C, and the prevalence of hypertension, ischemic/left bundle branch block (LBBB) electrocardiography (EKG) pattern, current smoking and alcohol use among subjects with underweight, normal weight, overweight, obesity I and II. Univariate analysis showed that SDNN, HR(DB), HF power and the square root of the LF/HF ratio differed among these five groups. Multivariate analysis showed that obesity I and II were inverse correlates of HR(DB) and HF power. Overweight, obesity I and II were positively associated with the square root of the LF/HF ratio. No BMI status was related to SDNN, 30/15 ratio or LF power. Underweight was not the independent correlate of any CAF indices.

CONCLUSIONS

The risk for altered CAF is significant in overweight and obese subjects, independent of cardiovascular risk factors. Underweight is not apparently associated with CAF change.

Urinary albumin excretion is independently associated with C-reactive protein levels in overweight and obese nondiabetic premenopausal women

OBJECTIVES

C-reactive protein (CRP) and microalbuminuria are nowadays considered markers of chronic inflammation of the arterial wall and of endothelial dysfunction, respectively. An increase of CRP levels and of urinary albumin excretion (UAE) rate have both been reported to be independently associated with a higher risk of cardiovascular morbidity and mortality in the general population. The aim of the present study was to evaluate the possible correlation between UAE and CRP concentrations in overweight and obese premenopausal women.

DESIGN AND SETTING

A cross-sectional study in a primary care setting.

SUBJECTS, MAIN OUTCOME MEASURES

CRP levels and UAE rate were measured in 103 overweight and obese premenopausal women, aged 18-45 years. Other measurements included: central fat accumulation, as evaluated by waist circumference, insulin resistance, as calculated by homeostatic model assessment (HOMAIR); fat-free mass (FFM), as measured by bioimpedance analysis; blood pressure; and fasting plasma levels of glucose, insulin, and lipids.

RESULTS

Urinary albumin excretion was positively correlated with body mass index (BMI) (P < 0.01), waist circumference (P < 0.001), diastolic blood pressure (P < 0.01), triglycerides (P < 0.01), HOMAIR (P < 0.05), and CRP levels (P < 0.05); and negatively associated with HDL cholesterol (P < 0.001). After multivariate analysis, diastolic blood pressure, HDL cholesterol, and CRP levels maintained their significant correlation with UAE.

CONCLUSION

Our study shows a strong relationship between UAE and CRP concentrations, irrespective of age and other anthropometric and metabolic variables. On this basis, it can be argued that inflammation of the arterial wall, as indicated by higher CRP plasma levels, and endothelial dysfunction, as shown by higher UAE rate, might represent simultaneous phenomena in the development of atherosclerosis in overweight and obese premenopausal women.

Obesity, blood pressure, and renal sodium handling

A substantial body of work has been recently directed toward elucidation of the relationships between body weight, blood pressure, and renal and vascular function. In this review only a few of the myriad studies are highlighted in order to survey areas of current investigation and controversy. Epidemiologic studies have confirmed the blood pressure-body weight relationship but suggest a link to insulin resistance. The majority of investigative work in the mechanism and abnormalities in obesity and their link to blood pressure have focused on the kidney as the primary organ of interest. In addition to alterations in renal blood flow and function, the sympathetic nervous system has also been implicated. The role of the major adrenal steroid dehydroepiandrosterone (DHEA) has been examined, as have the roles of bradykinin and leptin, the exiting new polypeptide thought to play a role in obesity.