Relationship between plasma leptin levels and the tumor necrosis factor-alpha system in obese subjects.
OBJECTIVE
To evaluate the relationship between plasma leptin and the tumor necrosis factor-alpha (TNFalpha), TNF receptor p60 (TNF-R1) and TNF receptor p80 (TNF-R2) concentrations in obese subjects.


METHODS
Case-control study.


METHODS
Outpatient's Service for Prevention and Treatment of Obesity at the University Hospital.


METHODS
Body mass index (BMI), waist circumference, hip circumference, waist-to-hip ratio (WHR), fasting plasma glucose, fasting plasma insulin, homeostasis model assessment of insulin resistance (HOMA IR), plasma leptin, TNFalpha, TNF-R1 and TNF-R2 concentrations were evaluated in obese subjects (n = 42) and in age- and gender-matched, lean healthy controls (n = 16).


RESULTS
In obese subjects, fasting plasma glucose and insulin, HOMA IR, plasma leptin, TNFalpha, TNF-R1 and TNF-R2 concentrations were significantly higher than in controls. Furthermore, females showed higher leptin, TNF-R1 and TNF-R2 plasma concentrations compared to males, in both control and obese subjects. In control subjects, plasma leptin concentrations showed a direct correlation with BMI (r=0.74, P<0.001), hip circumference (r=0.94, P<0.001), TNF-R1 (r=0.79, P<0.001) and TNF-R2 (r=0.64, P<0.01), and a negative correlation with WHR (r=-0.58, P<0.05). In obese subjects, we found a direct correlation between plasma leptin concentrations and BMI (r=0.67, P<0.001), hip circumference (r=0.66, P<0.001), fasting glucose (r=0.37, P<0.05), fasting insulin (r=0.31, P<0.05), HOMA IR (r=0.38, P<0.05), TNF-R1 (r=0.71, P<0.001) and TNR-R2 (r=0.66, P<0.001), while a negative correlation was found between circulating leptin and WHR (r=-0.44, P<0.01). In multivariate analysis, plasma leptin concentrations were significantly associated with BMI (P=0.015) and gender (P=0.047) in the control group, while in obese subjects, plasma leptin showed a significant association with BMI (P=0.019) and TNF-R1 (P=0.012).


CONCLUSIONS
Our results are consistent with the hypothesis that the TNFalpha system could be involved in the regulation of plasma leptin concentrations in obese subjects.
Corica
F
F
Department of Internal Medicine, School of Medicine, Policlinico Universitario, University of Messina, Italy.
Allegra
A
A
Corsonello
A
A
Buemi
M
M
Calapai
G
G
Ruello
A
A
Nicita Mauro
V
V
Ceruso
D
D
D000328:Adult; D015703:Antigens, CD / Q000097:blood; D001786:Blood Glucose / Q000032:analysis; D001824:Body Constitution; D015992:Body Mass Index; D016022:Case-Control Studies; D005215:Fasting; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D020738:Leptin; D016014:Linear Models; D008297:Male; D009765:Obesity / Q000097:blood*; D011506:Proteins / Q000378:metabolism*; D054411:Receptors, Leptin; D018124:Receptors, Tumor Necrosis Factor / Q000097:blood; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D015703:Antigens, CD; D001786:Blood Glucose; D007328:Insulin; C515448:LEPR protein, human; D020738:Leptin; D011506:Proteins; D054411:Receptors, Leptin; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha