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J Bilezikian

Publications and source records attributed to J Bilezikian.

2 recordsLinked to original sources
PubMed2001

Effects of daily treatment with parathyroid hormone on bone microarchitecture and turnover in patients with osteoporosis: a paired biopsy study.

We examined paired iliac crest bone biopsy specimens from patients with osteoporosis before and after treatment with daily injections of 400 U of recombinant, human parathyroid hormone 1-34 [PTH(1-34)]. Two groups of patients were studied. The first group was comprised of 8 men with an average age 49 years. They were treated with PTH for 18 months. The second group was comprised of 8 postmenopausal women with an average age 54 years. They were treated with PTH for 36 months. The women had been and were maintained on hormone replacement therapy for the duration of PTH treatment. Patients were supplemented to obtain an average daily intake of 1500 mg of elemental calcium and 100 IU of vitamin D. The biopsy specimens were subjected to routine histomorphometric analysis and microcomputed tomography (CT). Cancellous bone area was maintained in both groups. Cortical width was maintained in men and significantly increased in women. There was no increase in cortical porosity. There was a significant increase in the width of bone packets on the inner aspect of the cortex in both men and women. This was accompanied by a significant decrease in eroded perimeter on this surface in both groups. Micro-CT confirmed the foregoing changes and, in addition, revealed an increase in connectivity density, a three dimensional (3D) measure of trabecular connectivity in the majority of patients. These findings indicate that daily PTH treatment exerts anabolic action on cortical bone in patients with osteoporosis and also can improve cancellous bone microarchitecture. The results provide a structural basis for the recent demonstration that PTH treatment reduces the incidence of osteoporosis-related fractures.

Bone Density↗
PubMed2000

Primary hyperparathyroidism: pathophysiology and impact on bone.

Primary hyperparathyroidism has been associated with bone loss, especially at cortical skeletal sites. Results from studies evaluating the mineral density of cancellous bone have been more difficult to interpret. Most densitometry studies support the concept that the parathyroid hormone appears to be catabolic at cortical sites and may have anabolic effects at cancellous bone sites. Studies completed to date, however, have been limited by design, definitions of fracture and inadequate control groups. Primary hyperparathyroidism is now increasingly being detected during the asymptomatic phase. The need for parathyroidectomy has been questioned in such patients because there may be no disease progression in the absence of surgery. Medical management of primary hyperparathyroidism has to date been limited to estrogen replacement therapy in postmenopausal women. Identification of the calcium receptor has improved our understanding of calcium homeostasis, and significant reductions in calcium receptor levels have been detected in parathyroid adenomas. Thus, a new class of therapeutics may include the calcimimetic agents. Bisphosphonates are also currently being evaluated with regard to their impact on fracture prevention and their beneficial effects on bone mineral density.

Bone Density↗