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

Abstract

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 Ͻ 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 ϭ 0.001). Obese subjects were reevaluated 1 yr after LAGB, when their body mass index changed from 46.2 Ϯ 1.24 to 36.6 Ϯ 1.05 kg/m 2 (P Ͻ 0.01); the decrease in LVM correlated only with the decrease in leptin levels (P Ͻ 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

Association of Circulating Adipokines With Echocardiographic Measures of Cardiac Structure and Function in a Community‐Based Cohort

“…Similar to our observations, several population‐based studies, including MESA (Multi‐Ethnic Study of Atherosclerosis)10 and a previous study of elderly participants in the original cohort of FHS,29 have reported an inverse association between circulating leptin concentrations and LVM but no association with measures of LV systolic function 29. In contrast, other observational studies of men with hypertension,22 of severely obese patients23 and of patients with myocardial infarction24 have reported a positive association between leptin and cardiac hypertrophy. Furthermore, in patients with CAD16 and acute myocardial infarction,24 a positive association has been reported between circulating leptin levels and markers of LV diastolic dysfunction.…”

“…Accordingly, investigators have related circulating concentrations of adipokines to imaging indices of cardiac remodeling. These prior studies have typically been conducted in small samples, or samples with an overrepresentation of obese individuals or elderly people, and usually focused on a single adipokine 10, 11, 13, 21, 22, 23, 24, 25, 26…”

“…Prior investigations relating adipokines to cardiac structure and function have focused on single adipokines10, 11, 15, 16, 17, 18, 19, 20, 21 and related them to traditional measures of cardiac remodeling (such as LV mass [LVM]). These studies often focused on obese individuals with comorbidities16, 22, 23, 24, 25, 26, 27, 28 or the elderly20, 21, 29 and were limited by modest sample sizes. To our knowledge, no prior investigation has related a panel of adipokines of contemporary interest to a range of cardiac remodeling indices in a younger sample relatively free of comorbidities.…”

Early Effects of Gastric Banding (LGB) and of Biliopancreatic Diversion (BPD) on Insulin Sensitivity and on Glucose and Insulin Response after OGTT

“…It has also to be considered that changes of body weight with both BPD and LGB were quite reduced from the biological point of view. As a matter of fact, leptin, which is known to decrease after significant weight loss, did not change in subjects under study [21].…”

Effects of Bariatric Surgery on Cardiovascular Function

“…41 Furthermore, circulating leptin levels correlate well with left ventricular (LV) mass in morbid obesity both before and after bariatric surgery. 49 Adiponectin is among the highest produced adipokines, possessing both anti-inflammatory and antidiabetic properties, although levels are paradoxically decreased in obesity and insulin-resistance states. Early epidemiological data suggest that lower plasma concentrations of adiponectin are associated with the risk of coronary artery disease when adjusted for age and BMI, 43 whereas raised levels reveal a lower risk of myocardial infarction.…”