Leptin Levels in Diabetic and Nondiabetic Subjects

Abstract

The role of leptin in human pathophysiology elicits considerable interest in view of its potential role as a treatment tool for obesity and other insulin resistant states, like type 2 diabetes mellitus (T2DM). Leptin has been extensively studied in obese humans, and much less so in other pathologic conditions. Leptin level has been reported to correlate with percent body fat mass (%FM), fasting serum insulin (FPI), insulin sensitivity and blood pressure. The aim of this study was to compare the leptin concentration, and its relationship with some anthropometric and biochemical parameters related to insulin resistance in 140 moderately obese type 2 diabetics (T2DM) and 160 age and weight matched non-diabetic controls in order to get a better insight into the possible role of leptin in the metabolic abnormalities of diabetes. The leptin levels were lower in the diabetic population only when both sexes were combined (p < 0.05) and were higher in the females of both groups. Among the nondiabetics, the leptin levels appeared to be related to BMI, %FM, HDL and FPI, while this was not the case in the diabetics. After correction for BMI, leptin appeared to be correlated with the FPI levels only in the non-diabetic females. When plasma leptin was included in a multiple linear regression model with plasma leptin as a dependent variable, BMI, W:Hr and FPI levels were significantly related to leptin in the non diabetic population, while no relationship reached the level of statistical significance among the diabetics, with the exception of the borderline value for the FPI (p = .052). In conclusion, leptin levels were independent of any of the parameters examined in our diabetic population, possibly due to the progressive loss of the normal mechanisms of leptin regulation with advancing disease. Conclusive data can only be obtained from the longitudinal study of a cohort of newly diagnosed diabetic subjects.

The Determinants of Leptin Levels in Diabetic and Nondiabetic Saudi Males

“…Abu-Sayeed et al [30] found that lean diabetic patients have shown low leptin levels. These results were also reported by many other researchers [14, 31, 32]. Haffner et al [33] found no differences in the concentration of leptin levels between diabetic and nondiabetic subjects as well as no differences between obese and nonobese subjects.…”

“…Ahren et al [42] stressed that leptin levels are increased in patients with high BMI levels (obese). However, other studies argued that leptin levels were reduced in obese and diabetic patients, which attributed to the altered fat distribution [14, 32]. Matsubara et al [43] found that the concentration of serum leptin in women with high levels of BMI was increased compared to those in the middle and/or lower BMI group.…”

“…Leptin plays a critical role in human pathophysiology of a group of diseases because it elicits considerable interest in its potential in treating obesity and insulin resistance [14]. In other words, evidence suggests that leptin is a protein involved in the pathology of obesity [15].…”

Adiponectin and Leptin in Relation to Insulin Sensitivity

“…73 In a cross-sectional study of obese men, multiple regression analysis showed abdominal subcutaneous adipose tissue, glucose disposal rate (GDR) and BMI to explain most of the variability in serum leptin concentration. 74 Tatti et al 75 found that BMI, waist-to-hip ratio, and fasting plasma insulin were significantly related to leptin only in the nondiabetic population, but not in diabetic patients. On the other hand, Wauters et al 76 found that fat mass and gender are the main independent predictors of leptin concentration in type 2 diabetic 118 SOODINI AND HAMDY patients, and that insulin secretion and the degree of insulin resistance contribute significantly to leptin levels.…”

Effect of Orlistat on Plasma Leptin Levels and Risk Factors for the Metabolic Syndrome

“…7 Hyperleptinemia leads also to increased blood pressure via decreased blood flow in the splanchnic bed, 8 hypercoagulation, and increased PAI-1 levels 9 -all these being features of the MS. Leptin levels were also found to be lower in the diabetic population as compared to healthy subjects. 10 Orlistat is a lipase inhibitor leading to nonabsorption of 30% of the fat ingested with food. 11 The landmark study XENDOS (XENical in the prevention of Diabetes in Obese Subjects) has investigated the long-term use of Orlistat for (up to) 4 years in preventing the progression to type 2 diabetes in obese patients with MS. 12 The purpose of the present study was to assess the impact of treatment with Orlistat on serum leptin levels, weight loss, glycemic control, and cardiovascular risk factors involved in the MS.…”