Plasma leptin levels and coronary heart disease

Circulating leptin correlates with left ventricular mass in morbid (grade III) obesity before and after weight loss induced by bariatric surgery: a potential role for leptin in mediating human left ventricular hypertrophy

CONTEXT

Obesity is frequently associated with left ventricular hypertrophy, even when uncomplicated by hypertension or diabetes mellitus. Left ventricular hypertrophy is an important risk factor for congestive heart failure.

OBJECTIVE

The objective of this study was to evaluate the relationship between leptin and left ventricular mass in uncomplicated, morbid (grade 3) obesity and the existence of leptin receptors and intracellular signaling proteins in the human heart.

DESIGN

Left ventricular mass (LVM) was calculated through electrocardiogram reading in normotensive grade III obese patients (World Health Organization classification) undergoing bariatric surgery [laparoscopic adjustable gastric banding (LAGB)] at baseline and 1 yr later. The control group was composed of healthy lean normotensive subjects. Leptin receptors were detected by PCR and immunocytochemistry in human heart biopsies.

SETTING

This study was performed at university hospitals.

PATIENTS

Thirty-one grade 3 obese patients and 30 healthy nonobese normotensive, age- and sex-matched control subjects were studied.

INTERVENTION

Obese subjects underwent LAGB to induce weight loss and were evaluated at baseline and after 1 yr.

RESULTS

LVM, plasma leptin, glucose, insulin levels, and homeostasis model assessment index were higher in obese than in lean controls (P < 0.01); at univariate regression analysis, LVM correlated with body mass index, leptin, and homeostasis model assessment index; at multiple regression analysis, LVM only correlated with leptin levels (P = 0.001). Obese subjects were reevaluated 1 yr after LAGB, when their body mass index changed from 46.2 +/- 1.24 to 36.6 +/- 1.05 kg/m(2) (P < 0.01); the decrease in LVM correlated only with the decrease in leptin levels (P < 0.01). We demonstrated that long and short isoforms of the leptin receptor and intracellular proteins mediating leptin signaling were expressed in human heart by RT-PCR, immunocytochemistry, or both methods.

CONCLUSIONS

These data suggest that leptin could contribute to the left ventricular hypertrophy in humans.

Left ventricular hypertrophy and QT interval in obesity and in hypertension: effects of weight loss and of normalisation of blood pressure

BACKGROUND

Left ventricular hypertrophy (LVH) and prolonged QT interval at ECG (QTc) are common in both obesity and arterial hypertension (AH), and are risk factors for cardiovascular disease and sudden death.

METHODS

We compared the frequencies of LVH (ECG criteria) and QTc in obese-AH (n=41), in normotensive obese (n=75), in lean-AH (n=30), and in lean controls (n=68) comparable for age and sex; in obese patients, LVH and QTc were evaluated under basal conditions and 1 y later, that is, after a significant weight loss induced by bariatric surgery.

RESULTS

LVH was more frequent, and QTc was longer, in obese-AH, in normotensive obese, and in lean-AH than in lean controls; after weight loss, frequency of LVH decreased in obese subjects becoming normotensive (n=87), not in obese subjects remaining hypertensive (n=29), while QTc decreased in all obese subjects.

CONCLUSION

Weight loss can effectively reduce QTc; when concomitant AH disappears, weight loss can also reduce the prevalence of LVH. In obese patients remaining hypertensive, aggressive pharmacological treatment is therefore indicated to correct LVH.