Rapid decline in bone turnover markers but not bone mineral density in acromegalic patients after transsphenoidal surgery

Abstract

Growth hormone (GH) has growth and metabolic functions. It stimulates the production of insulinlike growth factor-I (IGF-I) in the liver. IGF-I mediates the growth promoting activities of GH. Knockout mouse models with disruption of GH receptor, IGF-I or IGF-I receptor, highlight the importance of GH and IGF-I in maintaining bone metabolism and bone mineral density (BMD) [1][2][3]. In human, lack of GH is associated with reduced BMD and osteoporosis is observed in patients with severe adult GH deficiency [4,5]. Furthermore, replacement therapy using recombinant human GH (rhGH) increases BMD in such patients [6,7]. These results indicate that GH and IGF-I play an important role in maintaining bone metabolism and BMD in adulthood, in addition to stimulating longitudinal bone growth in childhood. However, informationRapid decline in bone turnover markers but not bone mineral density in acromegalic patients after transsphenoidal surgery Abstract. Growth hormone (GH) and insulin-like growth factor-I (IGF-I) play important roles in maintaining bone metabolism and bone mineral density (BMD) in adulthood, in addition to stimulating longitudinal bone growth in childhood. However, information on the effect of GH excess on bone metabolism and BMD is incomplete and requires further analysis. The aim of this study is to clarify the effect of rapid decline in GH levels after transsphenoidal surgery (TSS) on bone metabolism in acromegalic patients. In this prospective study, 22 patients (11 males and 11 females) with active acromegaly underwent TSS. Bone formation marker (serum bone alkaline phosphatase: BAP), bone resorption marker (urinary type I collagen cross-linked N-telopeptide: urinary NTx) and BMD were measured before and at 3 and 12 months after TSS. BAP was significantly decreased at 12 months after TSS, but not at 3 months. Urinary NTx was significantly decreased at 3 and 12 months after TSS. BMD did not change after TSS. In conclusion, the rapid fall in GH level after TSS had no effect on BMD for up to 12 months after TSS despite the decrease in markers of bone formation and resorption.

Postoperative changes in bone metabolism and bone mineral density in Japanese patients with acromegaly: a 3-year prospective study

“…We previously reported changes in levels of bone turnover markers and BMD in acromegalic patients in the first year following TSS [6]. In the present study, BMD remained stable up to three years after TSS, despite significant changes in levels of bone turnover makers.…”

“…In all patients, GH, IGF-I, bone formation marker (serum bone alkaline phosphatase: BAP), bone resorption marker (urinary type I collagen cross-linked N-telopeptide: urinary NTx), and BMD were measured before surgery and at 3 months, 1 year, and 3 years after surgery as in our previous study [6].…”

“…1 year after TSS [6]. While this observation is meaningful, the follow-up period of that study might not have been sufficient to evaluate BMD in acromegalic patients after TSS.…”

“…The diagnosis of acromegaly and hypogonadism was described previously [6]. Hypoadrenalism was defined as a failed cortisol response (absolute value < 18 μg/ dL) to an insulin tolerance test (ITT).…”

Treatment of acromegaly increases BMD but reduces trabecular bone score: a longitudinal study

“…GH and IGF-1 are important regulators of bone growth modeling and remodeling (2). In patients with acromegaly, active disease is associated with increased bone turnover (3), and this condition is considered as one of the causes of secondary osteoporosis that can lead to increased fracture risk and therefore increased morbidity and mortality (1). Low bone mineral density (BMD) is an accepted surrogate marker for fracture risk (4).…”