Leptin is associated with vascular endothelial function in overweight patients with type 2 diabetes

Koka Motoyama,Ryutaro Numaguchi,Katsuhito Mori,Yuko Yamazaki,Masaaki Inaba,Hidenori Koyama,Shinya Fukumoto,Satoshi Imamura,Tetsuo Shoji,Naoya Kawano,Hiromi Urata,Tomoaki Morioka,Masanori Emoto

doi:10.1186/1475-2840-13-10

Koka Motoyama, Ryutaro Numaguchi

Open Access

https://doi.org/10.1186/1475-2840-13-10

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Abstract

BackgroundThe adipocyte-derived hormone leptin plays a key role in the regulation of appetite and body weight. Recent studies have suggested that leptin is also involved in the pathogenesis of obesity-related atherosclerosis and cardiovascular disease. In this study, we investigated the association of plasma leptin levels with vascular endothelial function in lean and overweight patients with type 2 diabetes.MethodsOne hundred seventy-one type 2 diabetic patients, of which 85 were overweight (body mass index (BMI) ≥ 25 kg/m2), were enrolled in this cross-sectional study. Plasma leptin concentrations were measured by enzyme-linked immunosorbent assay. Flow-mediated dilatation (FMD) of the brachial artery was measured to evaluate vascular endothelial function using ultrasound.ResultsNo significant difference in FMD was found between the lean and overweight groups (7.0 ± 3.8% and 6.5 ± 3.6%, respectively; p = 0.354). FMD was negatively correlated with age (r = −0.371, p < 0.001) and serum creatinine levels (r = −0.236, p = 0.030), but positively correlated with BMI (r = 0.330, p = 0.002) and plasma leptin levels (r = 0.290, p = 0.007) in the overweight group. FMD was not associated with any parameters in the lean group. Multiple regression analysis including possible atherosclerotic risk factors revealed that the plasma leptin level (β = 0.427, p = 0.013) was independently associated with FMD in the overweight group (R2 = 0.310, p = 0.025), but not the lean group.ConclusionPlasma leptin levels are associated with vascular endothelial function in overweight patients with type 2 diabetes.

Highlights

The adipocyte-derived hormone leptin plays a key role in the regulation of appetite and body weight
Association between plasma leptin levels and Flow-mediated dilatation (FMD) First, we examined the association between FMD and plasma leptin levels or clinical risk factors for atherosclerosis by simple linear regression analyses for the total population and for lean and overweight subjects separately (Table 2)
Plasma leptin levels were not associated with nitroglycerin-mediated dilatation (NMD) in either the lean or overweight group, which is in contrast to the relationship we found between plasma leptin levels and FMD

Summary

Introduction

The adipocyte-derived hormone leptin plays a key role in the regulation of appetite and body weight. We investigated the association of plasma leptin levels with vascular endothelial function in lean and overweight patients with type 2 diabetes. The integrated effect of leptin on vascular endothelial function, a key factor for the initiation and development of atherosclerotic vascular damage [7], remains to be elucidated, since contradictory findings have been reported from experimental and clinical studies. Human studies demonstrated that the serum leptin level is inversely associated with adenosinestimulated myocardial blood flow in young obese men [15], and with forearm endothelium-dependent vasodilatation (EDV) in the elderly [16]. Controversy persists over whether an independent clinical association between leptin and vascular endothelial function exists, since the associations in the abovementioned studies were no longer present or were attenuated after adjustment for body mass index (BMI) in humans [15,16]

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