Introduction: An increase in bone turnover is observed in active acromegaly which is due to the anabolic effect of high levels of GH and IGF-1. This decreases after normalization of IGF-1 levels. Sclerostin is an osteocyte-produced key negative regulator of bone formation, which may play a role in the persistence of bone mass after successful treatment of acromegaly, however currently no data are available.
Objective: To study the potential role of sclerostin in the maintenance of high/normal bone mass in patients in long-term remission after successful treatment of acromegaly.
Methods: Sclerostin was measured in the stored sera of 79 patients, mean age 58.9±11.5 years,49% female, in long-term remission from acromegaly, mean time of remission14.6±5.9 years. Data were compared to sclerostin levels measured in 91 healthy controls (mean age 51.1±16.9years; 59% female). BMD measurements were available in all acromegaly patients.
Results: Median plasma sclerostin was significantly lower in acromegaly patients compared to healthy controls respectively 118.3pg/ml±37.8pg/ml vs. 147.3±54.9pg/ml. This remained after adjusting for age, sex and BMI (adjusted Beta 37.8(95%CI 22.0-53.5,p<0.001). Mean BMD was in the high normal range at both lumbar spine(LS) and femoral neck(FN) sites. We found no significant relationship between plasma sclerostin levels and age, BMI, current IGF-1 levels or current BMD in the acromegaly patients.
Conclusion: Here we demonstrate that mean circulating sclerostin levels are lower in patients in long-term remission of acromegaly compared to healthy controls. This suggests a potentially permanent alteration in osteocyte function, resulting in impaired sclerostin production possibly resulting from the long-term exposure of osteocytes to high circulating levels of IGF-1 in the period of active acromegaly.