Introduction: Klotho is a transmembrane protein that attenuates insulin/insulin-like growth factor-1 (IGF-1) signalling and appears to be involved in ageing. Recent data suggest that soluble a-Klotho (sKlotho) is also elevated in acromegaly. The aim of this study was to assess serum levels of sKlotho in patients in relation to the activity of the disease and to compare with the control group.

Material and methods: We studied 55 patients with acromegaly and 29 healthy controls (CG). Patients were divided into three subgroups according to minimal GH (growth hormone) concentration during the oral glucose tolerance test (OGTT) and the IGF-1 concentration: a surgically cured acromegalic group (SCA), well-controlled acromegalic group (WCA), and active acromegaly group (AA). In all subjects, blood samples were taken to assess the concentration of sKlotho, GH, IGF-1, and biochemical markers.

Results: Soluble a-Klotho was highest in the AA group and lowest in the SCA group. The differences in sKlotho levels were statistically significant when the AA group was compared to the SCA, WCA, and CG groups (p = 0.000, p = 0.002, p = 0.001, respectively). There were no significant differences in sKlotho levels among the SCA, WCA, and CG groups. sKlotho positively correlated with GH levels in the WCA and WCA + SCA groups (r = 0.666, p = 0.009; r = 0.366, p = 0.047, respectively) and with the IGF-1 level in the AA group (r = 0.589, p = 0.021).

Conclusions: sKlotho is increased in active acromegaly and normalises after successful treatment. It could be a new biomarker of acromegaly activity. (Endokrynol Pol 2016; 67 (4): 390–396)