Serum leptin, soluble leptin receptor, free leptin index and bone mineral density in patients with primary biliary cirrhosis.
OBJECTIVE
The pathophysiology of osteoporosis in chronic liver diseases is unknown. Recent data suggest that serum leptin is associated with bone mineral density (BMD). In animal studies leptin was found to be a potent inhibitor of bone formation. We investigated the relationship between serum leptin levels, soluble leptin receptor (sOB-R), free leptin index (FLI) and BMD in patients with primary biliary cirrhosis (PBC).


METHODS
Ninety-four female patients with PBC were included in this study; 122 healthy women served as controls. Serum leptin levels were measured by radioimmunoassay, sOB-R by enzyme-linked immunosorbent assay. BMD was measured by dual energy X-ray absorptiometry in the lumbar spine and femoral neck.


RESULTS
Serum leptin was significantly lower in patients with PBC compared with healthy controls. No difference was found between the body mass index (BMI) of patients and controls. There was a strong positive correlation between leptin and BMI. In PBC no association was found between leptin, sOB-R and liver function tests, histological stages or the presence of osteoporosis. Osteoporosis was present in 38 patients. A positive correlation was found between serum leptin and femoral neck z-score even after adjustment for BMI, whereas serum sOB-R correlated inversely with the serum leptin level. There was no difference in FLI between the subgroups of PBC patients according to the stages of the disease.


CONCLUSIONS
We found a lower serum leptin level and a higher sOB-R in patients with PBC, which could not be explained by the difference in BMI. As leptin was associated with BMD, it may be hypothesized that leptin is involved in the complex regulation of bone metabolism in PBC.
Szalay
Ferenc
F
1st Department of Medicine, Semmelweis University, Budapest, Hungary. szalay@bel1.sote.hu
Folhoffer
Aniko
A
Horváth
Andrea
A
Csak
Timea
T
Speer
Gabor
G
Nagy
Zsolt
Z
Lakatos
Peter
P
Horváth
Csaba
C
Habior
Andrzej
A
Tornai
Istvan
I
Lakatos
Peter Laszlo
PL
D015502:Absorptiometry, Photon; D000368:Aged; D015519:Bone Density; D024042:Collagen Type I / Q000097:blood; D005260:Female; D005272:Femur Neck / Q000503:physiopathology; D006801:Humans; D020738:Leptin / Q000097:blood*; D008105:Liver Cirrhosis, Biliary / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D010024:Osteoporosis / Q000097:blood / Q000209:etiology / Q000503:physiopathology; D011956:Receptors, Cell Surface / Q000097:blood*; D054411:Receptors, Leptin
D024042:Collagen Type I; C515448:LEPR protein, human; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D015675:Osteocalcin