Serum leptin is elevated out of proportion to the body mass index in adolescent females with familial combined hyperlipidemia (FCH)

Lack of association between leptin levels and leptin gene polymorphism in obese women

The aim of the present study was to evaluate the relationship between oligopolymorphism in the 25th codon of leptin gene and obesity. Eighty-seven obese women and 75 healthy women were constituted obese and control groups. Body fat percent, fat mass and lean body mass were determined by bioimpedance meter and leptin levels were determined. The presence of 25th codon oligopolymorphism in the leptin gene was done by PCR-RFLP technique. Mean leptin levels were 38.5±22.0 ng/ml, and 147.9±44.8 ng/ml in the control and obese groups, respectively. The correlations of serum leptin level to body fat percentage and fat mass in the control group were significant. The correlations in the obese group were not significant. This data implies that the difference of leptin levels between control and obese groups are more likely to be associated with alterations in the leptin gene other than 25th codon or alterations in the leptin receptor gene.

Screening for Familial Combined Hyperlipidemia in Children Using Lipid Phenotypes

The purpose of this study was to screen for FCHL in children using serum lipid phenotypes. The subjects were 1190 (599 male, 591 female) children who participated in a screening and care program for life style-related diseases in school children. Total cholesterol, high-density lipoprotein cholesterol and triglyceride were determined, and information on the family history of parents was obtained by questionnaire. Candidates for FCHL were screened by the following criteria; type IIb hyperlipidemia, type IIa hyperlipidemia with positive family history of CHD, hyperlipidemia or both. We informed them of the results by mail. A second series of examinations to diagnose FCHL was performed on volunteer participants, including their parents. The candidates consisted of 9 children with type IIb and 27 with type IIa hyperlipidemia, 11 of whom participated, in the second series of examinations, in which 5 children were diagnosed with FCHL. The prevalence was 0.4%, suggesting that at least half of all individuals with FCHL already demonstrate hyperlipidemia in childhood.

Serum leptin levels in patients with nonalcoholic steatohepatitis

OBJECTIVE

Leptin is a peptide hormone that mainly regulates food intake and energy expenditure of human body. A close correlation between serum leptin levels and the percentage of body fat stores is well known. Nonalcoholic steatohepatitis (NASH) is a common disorder which causes serum liver enzyme elevation. In this study, the serum leptin levels were investigated in patients with NASH to determine a possible role in the pathogenesis and in patients with chronic viral hepatitis to ascertain the effect of hepatic inflammation on serum leptin level.

METHODS

Forty-nine patients (38 men, 11 women) with NASH diagnosed by biopsy, 32 patients with biopsy-proven chronic viral hepatitis (21 men and 11 women), and 30 healthy adults (17 men, 13 women) enrolled in the study. Fasting blood samples were obtained, and serum leptin levels were measured by ELISA. Body mass index (BMI) was calculated for all subjects, and serum insulin, C-peptide, and lipoprotein levels were also detected.

RESULTS

The mean serum leptin levels (+/-SEM) were 6.62 +/- 0.71, 4.24 +/- 1.0, and 4.02 +/- 0.46 ng/ml in NASH, chronic hepatitis, and the control group, respectively. Mean serum leptin level in the NASH group was significantly higher than those in the other groups tested. BMI was also slightly higher in the NASH group when compared to the other groups (26.7 +/- 0.3, 23.7 +/- 0.6, and 24.6 +/- 0.3, respectively). There was a significant correlation between BMI and serum leptin levels when all the subjects were evaluated together (NASH, hepatitis, and control groups, r = 0.337, p = 0.012) but not in the NASH group when evaluated alone (r = 0.238, p = 0.1). Of the predisposing factors for NASH, obesity was observed in 24% of patients and hyperlipidemia in 67%. Serum cholesterol and triglyceride levels were significantly higher in the NASH group than those in controls (p < 0.05). It has been detected that most of these patients consumed high amounts of fat in their dietary habits.

CONCLUSIONS

The serum leptin levels were significantly higher in patients with NASH, while they were not affected by chronic hepatitis. This elevation is out of proportion to BMI of these patients and may be related to hyperlipidemia in most. Elevated serum leptin levels, therefore, may promote hepatic steatosis and steatohepatitis.