A link between bone mineral density and serum adiponectin and visfatin levels in acromegaly

Two adipokines highly expressed in fat mass, adiponectin with antiinflammatory and antiatherogenic properties and visfatin with an insulin-mimetic effect, are potential contributors to bone metabolism. In acromegaly, data on adiponectin are contradictory, and there are no data on visfatin.

The aim of the study was to evaluate adiponectin and visfatin in acromegaly, compared to control subjects, and to analyze their relationship with body composition and bone markers.

Bone markers [osteocalcin, total amino-terminal propeptide of type 1 procollagen (total P1NP), carboxy-terminal telopeptide (beta-Crosslaps)], body composition (by dual-energy x-ray absorptiometry), adiponectin (by ELISA), and visfatin (by immunoanalysis)] were evaluated in 60 acromegalic patients (24 males and 36 females) and in 105 age- and gender-matched healthy controls (33 males and 72 females). Acromegalic patients were classified as controlled, with normal IGF-I and nadir GH no greater than 1 microg/liter (n = 41), or active (n = 19).

Acromegalic patients had lower adiponectin (P < 0.01), more lean body mass (P < 0.01), more total body mass (P < 0.01), higher bone formation markers (osteocalcin and total P1NP, P < 0.05 and P < 0.01, respectively), but less bone resorption markers (beta-Crosslaps, P < 0.001) than controls. No differences in visfatin and BMD were found between patients and controls. Adiponectin correlated negatively with BMD (r = -0.374; P < 0.05) and lean mass (r = -0.301; P < 0.05) and positively with age (r = 0.341; P < 0.001) in acromegaly. Visfatin correlated negatively with BMD (r = -0.359; P < 0.05). BMD was the predictor for adiponectin and visfatin.

Acromegalic patients present hypoadiponectinemia and a favorable bone marker profile. Adiponectin and visfatin could be a link between fat mass and bone in acromegaly.