Vitamin D and skeletal tissues

Abstract

It is now accepted that vitamin D is an integral part of a complex endocrine system, one with far-reaching implications in mineral metafwlism. Reviews of the sources, functions and metabolism of vitamin D, as currently understood, are presented as a prelude to discussions of the role of vitamin D in calcium and phosphorous homeostatis and po.ssible specific roles for vitamin D in tiiineralized tissues. Data describing a possible regulatory function for vitamin D in bone and bone protein metabolism are presented. Some of the controversy which presently exists regarding the biochemical mechanism of the action of this vitamin is discussed. Finally, the possible relationship of vitamin D and disorders of skeletal tissues is described.

Normal B cells fail to secrete interleukin‐12

“…In vivo loaded DC, but not B cells, induce IFN-y production by antigen-specific T cells. Interestingly, both DC and B cells induce IL-2 secretion by T cells when antigenic peptide is added in vitro, but IFN-y production is still only induced by DC, in agreement with the notion that different cytokine profiles are induced by different APC [36,371. This antigen-specific IFN-y production is probably due to IL-12 p75 secretion by DC, since addition of IL-12 p75 in vitro induces IFN-y secretion by T hybridoma cells stimulated by antigen and B cells (J.-C. GuCry, unpublished).…”

Interrelationship of the Spine, Rib Cage, and Shoulder

“…A, Progression of a self-mobilization technique for the upper thoracic spine that incorporates a greater demand on the patient's ability to control the movement of both her neck and her shoulder toward a range of motion associated with pain and instability. She is then advised to supplement her diet with the following: (1) glucosamine sulfate, chondroitin sulfate, vitamin E, and vitamin C to slow down the process of DJD at C5-6 and elsewhere; patients with diabetes or shellfish allergies should consult their physician before taking glucosamine sulfate, whereas those taking blood thinners should consult their physician before taking chondroitin sulfate 143-156 ; (2) magnesium to support muscle performance, strength training, and bone density 157-160 ; (3) microcrystalline hydroxyapatite (a source of calcium), zinc, copper, manganese, and vitamin D 3 to minimize the possible adverse effects on this 49-year-old woman's bone density, secondary to heavy tobacco and caffeine intake 156,[161][162][163][164][165] ; (4) bioflavonoids, which have been shown to inhibit the release of arachidonic acid, work as anti-inflammatory agents, and decrease tissue degeneration [166][167][168] ; and (5) omega-3 fatty acids (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]), which have been shown to inhibit the metabolism of arachidonic acid and provide a mild long-term anti-inflammatory effect. CASE STUDY 5.1-cont'd subside, additional exercises may be added to the progression.…”

Bone cell biology: The regulation of development, structure, and function in the skeleton

“…The active, hormonal form of vitamin Ds, 1,25-dihydroxyvitamin D3 (1,25) stimulates osteoclastic bone resorption in vitro (Herrmann-Erlee and Raisz et al, 1972c) and in vivo (Marie and Travers, 1983;Tanaka and DeLuca, 1971). Being at least 1,000 times more potent in stimulating bone resorption than other metabolites, 1,25 (calcitriol) is the most potent metabolite of vitamin D3 (Henry and Norman, 1984;Brommage and DeLuca, 1985;Audran, 1985;Finkelman and Butler, 1985). Administration of this hormone to rachitic rats maintained on a low-calcium, vitamin-D-deficient diet (Weisbrode et al, 1978), or to normal young mice (Tinkler et al, 1981;Marie and Travers, 1983) or rabbits (Popoff et al, 1988), causes a n increase in the number of osteoclasts.…”