Grynpas, Marc D. - University of Toronto - Institute of Biomaterials & Biomedical Engineering

个人简介

Senior Scientist, Samuel Lunenfeld Research Institute, Mount Sinai Hospital Department of Laboratory Medicine & Pathobiology Institute of Biomaterials & Biomedical Engineering Additional Appointments Department of Materials Science & Engineering Division of Orthopaedic Surgery, Department of Surgery

研究领域

Structure and chemistry of bone mineral and matrix Bone is heterogeneous, contains local areas which have just mineralized next to local areas which have been mineralized for longer periods of time. This heterogeneity renders analysis of whole bone misleading. We use the density fractionation technique to produce mineralization profiles in which newly-formed bone (low density fractions) can be separated from more mature bone, and we analyze the mineral and matrix m each fraction. In addition to chemical analyses we are using electron microscopy, X-ray and electron diffraction, neutron activation analysis and HPLC techniques. By studying the mineral-matrix interactions of the extracellular matrix of bone we are trying to understand the regulation of bone formation, mineralization and resorption. Changes in Bone Mineral and Matrix with Age and Diseases Mineralization profiles are a much more sensitive index of bone tissue age than the age of the animal. In normal physiological conditions there is a shift in the profile towards higher densities with aging. In pathological conditions either localized as in osteoarthritis or generalized as in osteoporosis subtle differences can be detected in the mineralization of the bone, confirming the view that in osteoporosis the nature of the bone changes as well as its quantity. We are correlating changes in bone tissue chemistry and architecture to bone mechanical strength. Effects of Trace Elements and Drugs on Bone It is possible to manipulate bones in to change their mineralization profile and therefore change their solubility and other material properties. We have shown that a high fluoride diet shifts bone mineralization profiles in rats as well as reducing bone solubility. We are also studying the affect of stable strontium on bone because strontium increases bone mass. In bisphosphonate treated animals we are studying the long term effects of lack of resorption on bone metabolism in animal models of arthritis and osteoporosis.

近期论文

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Porous calcium polyphosphate as load-bearing bone substitutes: In vivo study. Pilliar RM, Kandel RA, Grynpas MD, Hu Y. J Biomed Mater Res B Appl Biomater. 2012 Nov 10. Effect of potassium and magnesium doping on mechanical properties and in vitro degradation behavior of calcium polyphosphate. Abbarin N , Coyle TW, Grynpas MD. Journal of Materials Science. September 2012. Pages 1-10. Enhanced levels of non-enzymatic glycation and pentosidine crosslinking in spontaneous osteoarthritis progression. Willett TL, Kandel R, De Croos JN, Avery NC, Grynpas MD. Osteoarthritis Cartilage. 2012 Jul. 20(7):736-44. A 3D scanning confocal imaging method measures pit volume and captures the role of Rac in osteoclast function. Goldberg SR, Georgiou J, Glogauer M, Grynpas MD. Bone. 2012 Jul. 51(1):145-52. Evaluating the effects of mixed osteolytic/osteoblastic metastasis on vertebral bone quality in a new rat model. Wise-Milestone L, Akens MK, Rosol TJ, Hojjat SP, Grynpas MD, Whyne CM. J Orthop Res. 2012 May. 30(5):817-23. The incorporation of a zone of calcified cartilage improves the interfacial shear strength between in vitro-formed cartilage and the underlying substrate. St-Pierre JP, Gan L, Wang J, Pilliar RM, Grynpas MD, Kandel RA. Acta Biomater. 2012 Apr. 8(4):1603-15.