Dr Fox, Mr Miller, and Mr Newman are or were employees of and own stock in NPS Pharmaceuticals. Dr Turner serves as a consultant for Charles River Laboratories Preclinical Services. Ms Smith is employed by Charles River Laboratories Preclinical Services. Dr Recker serves as a consultant for Amgen, Eli Lilly & Co., GlaxoSmithKline, Merck, Novartis, NPS, Proctor & Gamble, Roche, and Wyeth.
Treatment of Skeletally Mature Ovariectomized Rhesus Monkeys With PTH(1-84) for 16 Months Increases Bone Formation and Density and Improves Trabecular Architecture and Biomechanical Properties at the Lumbar Spine†
Article first published online: 6 NOV 2006
Copyright © 2007 ASBMR
Journal of Bone and Mineral Research
Volume 22, Issue 2, pages 260–273, February 2007
How to Cite
Fox, J., Miller, M. A., Newman, M. K., Turner, C. H., Recker, R. R. and Smith, S. Y. (2007), Treatment of Skeletally Mature Ovariectomized Rhesus Monkeys With PTH(1-84) for 16 Months Increases Bone Formation and Density and Improves Trabecular Architecture and Biomechanical Properties at the Lumbar Spine. J Bone Miner Res, 22: 260–273. doi: 10.1359/jbmr.061101
- Issue published online: 4 DEC 2009
- Article first published online: 6 NOV 2006
- Manuscript Accepted: 1 NOV 2006
- Manuscript Revised: 30 AUG 2006
- Manuscript Received: 8 MAR 2006
- ovariectomized primate;
- bone turnover markers;
- bone densitometry;
- bone histomorphometry;
- bone strength
Histomorphometric studies of treatments for osteoporosis in humans are restricted to iliac crest biopsies. We studied the effects of PTH(1-84) treatment at the lumbar spine of skeletally mature ovariectomized rhesus monkeys. PTH increased bone turnover, rapidly normalized BMD, and increased vertebral compressive strength. PTH increased trabecular bone volume primarily by increasing trabecular number by markedly increasing intratrabecular tunneling.
Introduction: Histomorphometric studies of the anabolic properties of PTH(1-84) (PTH) and related peptides in human bone are restricted to iliac crest biopsies. The ovariectomized (OVX) monkey is an accepted model of human postmenopausal bone loss and was used to study the effects of PTH treatment at clinically relevant skeletal sites.
Materials and Methods: Skeletally mature rhesus monkeys were OVX or sham-operated and, after a bone depletion period of 9 months, treated daily for 16 months with PTH (5, 10, or 25 μg/kg). Markers of bone formation (serum osteocalcin) and resorption (urine N-telopeptide [NTX]) and lumbar spine BMD were measured throughout the study. Trabecular architecture and vertebral biomechanical properties were quantified at 16 months.
Results: PTH treatment induced dose-dependent increases in bone turnover but did not increase serum calcium. Osteocalcin was significantly increased above OVX controls by 1 month. NTX was significantly elevated at 1 month with the highest dose, but not until 12 months with the 5 and 10 μg/kg doses. Lumbar spine BMD was 5% lower in OVX than in sham animals when treatment was started. All PTH doses increased BMD rapidly, with sham levels restored by 3–7 months with 10 and 25 μg/kg and by 16 months with 5 μg/kg. PTH treatment increased trabecular bone volume (BV/TV), primarily by increasing trabecular number, and dose-dependently increased bone formation rate (BFR) solely by increasing mineralizing surface. The largest effects on BV/TV and yield load occurred with the 10 μg/kg dose. The highest dose reduced trabecular thickness by markedly increasing intratrabecular tunneling.
Conclusions: PTH treatment of OVX rhesus monkeys increased bone turnover and increased BV/TV, BMD, and strength at the lumbar spine. All PTH doses were safe, but the 10 μg/kg dose was generally optimal, possibly because the highest dose resulted in too marked a stimulation of bone remodeling.