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PTH treatment activates intracortical bone remodeling in patients with hypoparathyroidism

Publikation: KonferencebidragPosterForskning

Hypoparathyroidism (hypoPT) is characterized by a state of low bone turnover and high BMD. We have previously shown that hypoPT patients treated with PTH(1-84) for six months have highly increased bone turnover markers and a decrease in aBMD at the hip and spine(1). The present study aims to investigate the effect of PTH(1-84) on cortical bone and intracortical bone remodeling in hypoPT. The study was conducted on 20 transiliac bone biopsies from hypoPT patients after six months of treatment with either PTH(1-84) 100 µg s.c./day N=10 or placebo N=10. The groups were age- (±6 years) and gender-matched. Age, duration of disease, and etiology of hypoPT did not differ between groups. A comprehensive analysis of the cortical bone was performed including estimates of cortical porosity, and pore density (# of pores/mm2). The remodeling stage of all intracortical pores was evaluated, and pore area and diameter were measured. Cortical porosity and pore density did not differ between groups, but PTH treatment had a marked effect on the remodeling status of the pores. The percentage of pores undergoing remodeling was higher in the PTH-group than in placebo-group reported as median values (IQR[25-75%]) (52% [45-59%] vs. 18% [12-34%] of pore number, p<0.001). Interestingly, this PTH-induced increase was mainly due to a higher proportion of formative pores (27% [23-40%] vs. 6% [3-7%]; p<0.001) and mixed resorptive/formative pores (15% [9-16%] vs. 4% [1-8%]; p=0.004), whereas the percentage of resorptive pores (9% [5-11%] vs. 11% [6-19%], ns) did not differ between the PTH- and the placebo-group, respectively. The PTH-induced change was even greater when assessing the cortical porosity (% of pore area) rather than the pore number; PTH- vs. placebo-treated: resorptive pores 10% [3-20%] vs. 37% [8-74%] (p=0.02); mixed resorptive and formative pores 48% [36-61%] vs. 7% [1-17%] (p<0.001); formative pores 24% [16-32%] vs. 1% [1-3%] (p<0.001). Collectively, these data suggest an increased activation of intracortical bone remodeling with a change in the relative proportion of resorptive and formative pores, which may be due to a shortening of the intracortical resorptive/reversal phase in response to PTH treatment of hypoPT. Furthermore, the PTH-treatment did not increase cortical porosity or pore density.
OriginalsprogEngelsk
Udgivelsesår8 sep. 2017
StatusUdgivet - 8 sep. 2017
BegivenhedAmerican Society of Bone and Mineral research annual meeting - Colorado Convention Center, Denver, USA
Varighed: 8 sep. 201711 sep. 2017

Konference

KonferenceAmerican Society of Bone and Mineral research annual meeting
LokationColorado Convention Center
LandUSA
ByDenver
Periode08/09/201711/09/2017

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