Related Experiment Video
Updated: Jul 23, 2026

Longitudinal Evaluation of Mouse Hind Limb Bone Loss After Spinal Cord Injury using Novel, in vivo, Methodology
Published on: December 7, 2011
Combined calcitriol-pamidronate therapy for bone hyperresorption in spinal cord injury
B Chen1, J I Mechanick, D M Nierman
1The Department of Rehabilitation Medicine, The Mount Sinai School of Medicine, New York, New York, USA.
Objective:
To determine the biochemical effects of combined calcitriol-pamidronate therapy on bone hyperresorption in patients with spinal cord injury (SCI).
Methods:
This was a retrospective study of 21 SCI inpatients (4 women and 17 men, mean age 34 years) treated for bone hyperresorption. Initial treatment was 0.5 microg oral calcitriol once daily and 1,250 mg CaCO3 twice a day (1000 mg elemental calcium/day). On days 4 through 6 following the initial treatment, patients received 30 mg pamidronate intravenously once daily (total of 3 doses). Urinary N-telopeptide (NTx) and calcium excretion rates, and serum parathyroid hormone (PTH), 25-hydroxyvitamin D (25-D), 1,25-dihydroxyvitamin D (1,25-D), calcium, and phosphorus levels were measured within 2 weeks prior to and 2 weeks following pamidronate therapy.
Results:
Patients demonstrated increased urinary NTx and calcium excretion, indicative of bone hyperresorption, and suppressed PTH and 1,25-D levels as early as 9 days post-SCI. Combined calcitriol-pamidronate therapy decreased urinary NTx and calcium excretion by 71% (P < .001) and 73% (P < .001), respectively. This therapy also increased serum levels of PTH (P <.05) and 1,25-D (P < .005). Post-pamidronate hypocalcemia or hypophosphatemia was observed in 44% (P < .01) or 53% (P < .01), respectively.
Conclusion:
Combined calcitriol-pamidronate therapy significantly inhibited bone hyperresorption in SCI patients.
Related Concept Videos
Bone Remodeling
Bone Disorders
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
Hormones and Bone Tissue
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
Skeleton and Calcium Homeostasis
Synthesis and Functions of Calcitonin
The exact mechanisms by which calcitonin operates in calcium homeostasis remain elusive, but its significance is evident in several vital...
Urinary Tract Calculi IV: Nutrition Therapy and Prevention

