Visfatin as a marker of adipose dysfunction and metabolic impairment in active acromegaly and its possible use during the follow-up

Abstract

Background Visfatin is an adipokine with insulin-mimetic and adipogenic effect related to insulin resistance (IR) and visceral adipose mass. Although acromegaly is characterized by both adipose dysfunction and IR, data on visfatin levels in acromegaly are very scarce and in the few existing studies no difference was reported between acromegalic patients and controls. Aim To evaluate the visfatin levels in acromegaly in relation to disease activity and type of treatment. Subjects and Methods Data of 56 patients (31 M, age 59 ± 12 yrs) were analyzed. Sixteen patients were newly diagnosed (ND), while the remaining were in therapy with somatostatin analogues (SA, 21), pegvisomant (PE, 12) and after 6 months of surgery (SU,7). Among all, 33 resulted not controlled (16 ND, 10 SA, 5 PE, 2 SU) and 23 controlled (11 SA, 7 PE, 5 SU). In addition to routine anthropometric, hormonal and metabolic parameters, visfatin, leptin and adiponectin levels were evaluated. Results Uncontrolled patients showed higher levels of visfatin (1.51 ± 0.44 vs 0.21± 0.22 ng/ml; p<0.001). and lower levels of leptin (0.89 ± 0.55 vs 3.49 ± 1.28 ng/ml; p<0.001) in concomitant with higher insulin (p=0.034), Homa-IR (p<0.001), visceral adiposity index (p<0.001), triglycerides (p<0.001) and lower ISI Matsuda (p<0.001), HDL cholesterol (p<0.001) than controlled, with no significant difference in adiponectin levels. When we compared visfatin levels between untreated and treated patients, we found higher concentrations in the first group (1.54 ± 0.58 ng/ml) than in patients treated with SA (0.86 ± 0.62 ng/ml; p=0.002), PE (0.32 ± 0.51 ng/ml; p=0.002) or SU (0.48 ± 0.65 ng/ml; p=0.004), while no difference was found among different treatments. A strong correlation was found between visfatin and GH (nadir, AUC), IGF-1 and ISI Matsuda (all p<0.001). Conclusions In active acromegaly visfatin could be considered a useful tool for the evaluation of metabolic alterations, such as IR and adipose dysfunction, and a marker of the disease control regardless of type of treatment.