Abstract: SA-PO266
The Importance of Biologically Active Vitamin D for Mineralization by Osteocytes After Parathyroidectomy for Renal Hyperparathyroidism
Session Information
- Bone and Mineral Metabolism: Calcium, Magnesium, Kidney Stones
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Bone and Mineral Metabolism
- 402 Bone and Mineral Metabolism: Clinical
Authors
- Yajima, Aiji, Indiana University, School of Medicine, Indianapolis, United States
- Tsuchiya, Ken, Tokyo Women's Medical University, Shinjuku-ku, Japan
- Nitta, Kosaku, Tokyo Women's Medical University, Shinjuku-ku, Japan
Background
Hypomineralized matrix is a factor determing bone mineral density. Increased perilacunar hypomineralized bone area is caused by reduced mineralization by osteocytes.The importance of vitamin D in the mineralization by osteocytes was investigated in hemodialysis patients who underwent total parathyroidectomy (PTX) with immediate autotransplantation of diffuse hyperplastic parathyroid tissue. No previous reports on this subject exist.
Methods
The study was conducted in 19 patients with renal hyperparathyroidism treated with PTX. In 15 patients, the serum calcium levels were maintained by subsequent administration of alfacalcidol (2.0 µg/day), intravenous calcium gluconate, and oral calcium carbonate for four weeks after PTX (Group I). This was followed in a suset of for patients in Group I by a reduced dose of 0.5 µg/day until one year following PTX; this was defined as Group II. In the remaining four patients, who were not in Group I, the serum calcium levels were maintained without subsequent administration of alfacalcidol (Group III). Transiliac bone biopsy specimens were obtained in all groups before and 3 or 4 weeks after PTX to evaluate the change of hypomineralized bone area. In addition, patients from Group II underwent a third bone biopsy one year folllowing PTX.
And we did Raman measurements ffrom the same sections as those used for histology.
Results
A significant derease of perillacunar hypominerallized bone area was obsered 3 or 4 weeks after PTX in all Group I and II patients. The area was increased in the Group II patients one year following PTX. In Group III patients, an increase of hypomineralized bone area was observed four weeks after PTX.
Mineral maturity, defined by the bone's carbonate and shown as CO32-v1/PO43-v1, did not change following PTX in Group I and Group III. Crystallinity of the mineral did not change after PTX in either Group I and Group III.
Conclusion
The maintenance of a proper dose of vitamin D is necessary for mineralization by osteocytes, which is important to increase bone mineral density after PTX for renal hyperparathyroidism. Mineral maturity and crystallinity are not expected within 3-4 weeks after PTX.