Summary
Two rheumatic syndromes associated with deposition of calcium phosphate crystals in soft tissues of the shoulder have prompted us to study the cellular mechanisms of calcium phosphate crystal solubilization. Synthetic45Ca labeled calcium phosphate crystal aggregates were solubilized by cultured human fibroblasts or monocytes. Such solubilization required crystal cell contact and was inhibited by chloroquine and ammonium. We hypothesize that the mechanism of crystal solubilization involves phagocytosis followed by dissolution in the acidic environment of secondary lysosomes. Study of the mechanism of calcium phosphate solubilization may be important in understanding resorption of extra-osseus as well as osseus calcification. Intracellular release of calcium from calcium phosphate crystals may also explain our previous observation that hydroxyapatite and other calcium-containing crystals are mitogenic stimuli for fibroblasts and synovial cells.
Similar content being viewed by others
References
McCarty DJ, Halverson PB, Carrera GF, Brewer BJ, Kozin F (1981) “Milwaukee Shoulder”—association of microspheroids containing hydroxyapatite crystals, active collagenase, and neutral protease with rotator cuff defects. I. Clinical aspects. Arthritis Rheum 24:464–473
Halverson PB, Cheung HS, McCarty DJ, Garancis J, Mandel N (1981) “Milwaukee Shoulder”—association of microspheroids containing hydroxyapatite crystals, active collagenase, and neutral protease with rotator cuff defects. II. Synovial fluid studies. Arthritis Rheum 24:474–483
Uhthoff HK, Sarkar K, Maynard JA (1976) Calcifying tendinitis. A new concept of its pathogenesis. Clin Orthop 188:164–168
Uhthoff HK, Sarkar K (1978) Calcifying tendinitis. Its pathogenetic mechanism and a rationale for its treatment. Int Orthop 2:187–193
Evans RW, Cheung HS, McCarty DJ (1983) Uptake and dissolution of calcium phosphate crystals by cultured canine synovial cells (Abstract). Arthritis Rheum (suppl) 26:S60
Main RK, Wilkins MJ, Cale LJ (1959) A modified calcium phosphate for column chromatography of polynucleotides and proteins. J. Am Chem Soc 81:6490–6495
Spencer M (1978) Hydroxyapatite for chromatography. II. Sources of variability and improved methods of preparation. J. Chromatography 166:435–446
McCarty DJ, Lehr JR, Halverson PB (1983) Crystal populations in human synovial fluid: identification of apatite, octacalcium phosphate, and tricalcium phosphate. Arthritis Rheum 26:1220–1224
Cheung HS (1980) An improved method of establishing human fibroblast cultures from explants. J Tissue Culture Methods 6:39–40
Boyum A (1968) Isolation of mononuclear cells and granulocytes from human blood. Isolation of mononuclear cells by one centrifugation and of granulocytes by combining centrifugation and sedimentation at 1g. Scand J Clin Invest 21(Suppl 97):77–89
Cohen F (1980) Cell-mediated immunologic responses In: Sonnenwirth AC, Jarrett L (eds) Gradwohl's clinical laboratory methods and diagnosis. 8th ed, C. V. Mosby, St. Louis, Toronto, London, pp 1237–1238
Yam LT, Li CY, Crosby WH (1971) Cytochemical identification of monocytes and granulocytes. Am J Clin Pathol 55:283–290
Teitelbaum SL, Stewart CC, Kahn AJ (1979) Rodent peritoneal macrophages as bone resorbing cells. Calcif Tissue Int 27:255–261
Lowry OH, Roseborough NJ, Farr LA, Randall RJ (1951) Protein measurement with the Folin Phenol reagent. J Biol Chem 193:265–275
Wise, KS (1973) Studies on antigens associated with Wilm's tumor (Nephroblastoma). Ph.D. dissertation, Department of Biochemistry, University of Southern California
Merchant DJ, Kahn RH, Murphy WH (1964) Handbook of cell and organ culture, 2nd ed, pp 157
Kahn AJ, Stewart CC, Teitelbaum SL (1978) Contact-mediated bone resorption by human monocytes in vitro. Science 199:988–990
McArthur W, Yaari AM, Shapiro IM (1980) Bone solubilization by mononuclear cells. Lab Invest 42:450–456
Chambers TJ (1981) Resorption of bone by mouse peritoneal macrophages. J Pathol 135:295–299
Christoffersen J, Christoffersen MR, Kjaegaard N (1978) The kinetics of dissolution of calcium hydroxyapatite in water at constant pH. J Crystal Growth 43:501–511
Hollemans M, Elferink RO, DeGroot PG, Strijland A, Tager JM (1981) Accumulation of weak bases in relation to intralysosomal pH in cultured human skin fibroblasts. Biochim Biophys Acta 643:140–151
Ohkuma S, Poole B (1978) Fluorescence probe measurement of the intralysosomal pH in living cells and the perturbation of pH by various agents. Proc Natl Acad Sci USA 75:3327–3331
Bonucci E (1974) The organic-inorganic relationships in bone matrix undergoing osteoclastic resorption. Calcif Tissue Res 16:13–36
Garancis JC, Cheung HS, Halverson PB, McCarty DJ (1981) “Milwaukee Shoulder”: association of microspheroids containing hydroxyapatite crystals, active collagenase and neutral protease with rotator cuff defects. III. Morphologic and biochemical studies of an excised synovium showing chondromatosis. Arthritis Rheum 24:481–491
Cheung HS, Halverson PB, McCarty DJ (1981) Release of collagenase, neutral protease, and prostaglandins from cultured mammalian synovial cells by hydroxyapatite and calcium pyrophosphate dihydrate crystals. Arthritis Rheum 24:1338–1344
Cheung HS, McCarty DJ (1982) Mitogenic effects of hydroxyapatite (HA) and calcium pyrophosphate dihydrate (CPPD) crystals on cultured synovial cells (abstract). Arthritis Rheum 25(suppl):S77
Dulbecco R, Elkington J (1975) Induction of growth in resting fibroblastic cell cultures by Ca++. Proc Natl Acad Sci USA 72:1584–1588
Nykforiak CJ, Young RB, Phillips TA (1980) Changes in intracellular Ca2+ distribution during the transition of fibroblasts from the proliferating to the stationary state. Biochem Biophys Res Commun 3:583–587
Cheung HS, McCarty DJ (1984) Intracellular dissolution is essential for mitogenesis induced by crystals containing calcium (abstract). Arthritis Rheum 27(suppl):S49
Eilon G, Raisz LG (1982) Chloroquine, hydroxystilbamidine, and dapsone inhibit resorption of fetal rat bone in organ culture. Calcif Tissue Int 34:506–509
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Evans, R.W., Cheung, H.S. & McCarty, D.J. Cultured human monocytes and fibroblasts solubilize calcium phosphate crystals. Calcif Tissue Int 36, 645–650 (1984). https://doi.org/10.1007/BF02405384
Issue Date:
DOI: https://doi.org/10.1007/BF02405384