The Role of Soluble α-klotho Protein in Acromegaly

Abstract

Soluble α-klotho (sαKl) is an isoform of the α-klotho protein that regulates calcium metabolism but also has anti-aging, anti-apoptotic, and tumor suppressor effects. The assumption that sαKl could inhibit the insulin-like growth factor 1 (IGF-1) signaling pathway has increased the interest of its research in acromegaly - a pathology characterized by an excess of growth hormone (GH) and IGF-1. This review aimed to identify the role of sαKl in acromegaly. Most studies have identified higher concentrations of sαKl in acromegaly versus non-GH pituitary adenomas (PAs) or healthy subjects. Also, the sαKl level was higher in active acromegaly versus controlled or cured disease. Moreover, sαKl positively correlated with GH, IGF-1, and GH-secreting PA size. The increased level of sαKl seems to be due to the autonomous secretion of GH, considering their drastic decrease after transsphenoidal surgery. The data regarding the relationship between sαKl, age, and gender in acromegaly are inconsistent. The latest research noted a correlation between sαKl and various parameters for monitoring the quality of life in acromegaly. In conclusion, sαKl could reflect the disease activity. Furthermore, sαKl would represent an alternative for monitoring acromegalic patients with discrepancies between IGF-1 and GH.