Overfeeding-induced weight gain elicits decreases in sex hormone-binding globulin in healthy males-Implications for body fat distribution.

Objective: Obesity and upper-body fat elevates cardiometabolic risk. However, mechanisms predisposing to upper-body fat accumulation are not completely understood. In males, low testosterone (T) frequently associates with obesity, and estrogen deficiency may contribute to upper-body adiposity.

Experimental Weight Gain Increases Ambulatory Blood Pressure in Healthy Subjects: Implications of Visceral Fat Accumulation.

Objective: To examine whether experimentally induced weight gain raises ambulatory blood pressure (BP) in healthy subjects and identify any relationship between changes in BP and changes in regional fat distribution.

Patients And Methods: Twenty-six normal weight subjects were randomized to 8 weeks of weight gain through overfeeding (n=16; age, 30.4±6.

Daytime cardiac repolarization in patients with obstructive sleep apnea.

Purpose: Obstructive sleep apnea (OSA) has been implicated in complications of cardiovascular disease, including arrhythmias and sudden cardiac death (SCD). Prolonged QT interval is associated with arrhythmias and SCD in patients with cardiovascular disease and apparently healthy humans. Apneic episodes during sleep in OSA patients are associated with QT prolongation due to increased vagal activity, but it is not understood whether chronic QT prolongation persists during normoxic daytime wakefulness.

Experimental sleep restriction causes endothelial dysfunction in healthy humans.

Background: Epidemiologic evidence suggests a link between short sleep duration and cardiovascular risk, although the nature of any relationship and mechanisms remain unclear. Short sleep duration has also been linked to an increase in cardiovascular events. Endothelial dysfunction has itself been implicated as a mediator of heightened cardiovascular risk.

Effects of experimental sleep restriction on caloric intake and activity energy expenditure.

Background: Epidemiologic studies link short sleep duration to obesity and weight gain. Insufficient sleep appears to alter circulating levels of the hormones leptin and ghrelin, which may promote appetite, although the effects of sleep restriction on caloric intake and energy expenditure are unclear. We sought to determine the effect of 8 days/8 nights of sleep restriction on caloric intake, activity energy expenditure, and circulating levels of leptin and ghrelin.

Effects of weight gain and weight loss on regional fat distribution.

Background: Normal-weight adults gain lower-body fat via adipocyte hyperplasia and upper-body subcutaneous (UBSQ) fat via adipocyte hypertrophy.

Objectives: We investigated whether regional fat loss mirrors fat gain and whether the loss of lower-body fat is attributed to decreased adipocyte number or size.

Design: We assessed UBSQ, lower-body, and visceral fat gains and losses in response to overfeeding and underfeeding in 23 normal-weight adults (15 men) by using dual-energy X-ray absorptiometry and abdominal computed tomography scans.

Leptin signaling in adipose tissue: role in lipid accumulation and weight gain.

Rationale: The link between obesity, hyperleptinemia, and development of cardiovascular disease is not completely understood. Increases in leptin have been shown to impair leptin signaling via caveolin-1-dependent mechanisms. However, the role of hyperleptinemia versus impaired leptin signaling in adipose tissue is not known.

Effect of weight gain on cardiac autonomic control during wakefulness and sleep.

Obesity has been associated with increased cardiac sympathetic activation during wakefulness, but the effect on sleep-related sympathetic modulation is not known. The aim of this study was to investigate the effect of fat gain on cardiac autonomic control during wakefulness and sleep in humans. We performed a randomized, controlled study to assess the effects of fat gain on heart rate variability.

Association between plasma adiponectin levels and unstable coronary syndromes.

Aims: Obesity is a risk factor for an acute coronary syndrome (ACS). The association between elevated body mass index (BMI) and ACS is independent of most traditional risk factors, suggesting a possible contribution of other body fat-related mediators. This study evaluated the association between adiponectin and ACS.

High sensitivity C-reactive protein: a novel predictor for recurrence of atrial fibrillation after successful cardioversion.

Objectives: We sought to test the hypothesis that C-reactive protein (CRP) can predict the recurrence of atrial fibrillation (AF) after successful electrical cardioversion (CV).

Background: In patients with AF, CRP levels are predictive of immediate failure of CV.

Methods: We prospectively measured high-sensitivity CRP in 67 patients with AF or atrial flutter who underwent successful electrical CV.

Association of atrial fibrillation and obstructive sleep apnea.

Background: Obstructive sleep apnea (OSA) is associated with recurrent atrial fibrillation (AF) after electrocardioversion. OSA is highly prevalent in patients who are male, obese, and/or hypertensive, but its prevalence in patients with AF is unknown.

Methods And Results: We prospectively studied consecutive patients undergoing electrocardioversion for AF (n=151) and consecutive patients without past or current AF referred to a general cardiology practice (n=312).

Independent association between plasma leptin and C-reactive protein in healthy humans.

Background: C-reactive protein (CRP) is synthesized from the liver and is regulated by cytokines, especially interleukin-6. Leptin, the adipocyte-derived protein product of the ob gene, is related to amount of body fat. The long form of the leptin receptor resembles cytokine receptors, which include the interleukin-6 receptor.