Ammann, P, Zacchetti, G, Gasser, Juerg Andreas, Lavet, C and Rizzoli, R (2015) Protein malnutrition attenuates bone anabolic response to PTH in female rats. Endocrinology.

Abstract

Abstract
Parathyroid Hormone (PTH) is indicated for the treatment of severe osteoporosis. Elderly Osteoporotic patients frequently suffer from protein malnutrition, which is associated with low serum IGF-I level. IGF-I appears to be involved in the anabolic effects of PTH on bone. We investigated whether the reduction in dietary protein intake, which reduces IGF-I levels, versus a normal protein diet would influence the bone anabolic response to PTH.
Six month old female rats were either pair fed an isocaloric low protein (2.5 % casein, LP) or a normal protein diet (15% casein, NP) for 2 weeks. The rats continued on their diet while being treated with 5 or 40μg/kg recombinant human PTH amino-terminal fragment 1-34 (PTH(1-34)) daily, or with vehicle for 4 weeks. At the end of this period, areal BMD, BMC, microstructure and bone strength in axial compression of proximal tibia or 3-point bending for midshaft tibia were measured, and blood was collected for the determination of IGF-I and osteocalcin.
After 4 weeks of PTH(1-34), the dose dependent increase of proximal tibia BMD, trabecular microstructure variables and bone strength were attenuated in rats fed a low protein diet as compared to rats on a normal protein intake. At the level of midshaft tibia cortical bone, PTH(1-34) had exerted an anabolic effect only in the NP, but not in the LP diet group.
Protein malnutrition attenuates the bone anabolic effects of PTH(1-34) in rats. These results suggest that a sufficient protein intake should be recommended for osteoporotic patients undergoing PTH therapy.

Item Type:	Article
Keywords:	PTH, Protein under nutrition, bone strength
Date Deposited:	02 May 2016 23:45
Last Modified:	02 May 2016 23:45
URI:	https://oak.novartis.com/id/eprint/20508