Correlation of an osteoclast antigen and ruffled border on giant cells formed in response to resorbable substrates

Abstract

The osteoclast is the specialized multinucleated cell primarily responsible for the degradation of the organic and inorganic components of bone matrix. The functional and developmental relationship between osteoclasts and foreign body giant cells is unclear. The osteoclast plasma membrane ruffled border juxtaposed to the bone surface is a unique morphologic characteristic of active osteoclasts. In the studies reported here giant cell formation was induced in response to a variety of materials implanted onto the richly vascularized chick chorioallantoic membrane. Light and electron microscopic techniques were used to examine the morphologic characteristics of the giant cells. In addition, immunohistochemical methods were used to demonstrate the appearance of a 150 kD cell surface antigen on chicken osteoclasts recognized by monoclonal antibody 121F. Giant cells that formed in response to mineralized bone particles exhibited ruffled borders and stained positively with the 121F antibody. Many giant cells that formed in response to hydroxyapatite possessed ruffled borders similar to but not as extensive as those observed on giant cells formed on bone. Immunohistochemical localization of the 121F antigen on these cells suggested that the antigen was present, but staining intensity was reduced compared to that of bone-associated giant cells. The formation of mineral matrix complexes by the adsorption to hydroxyapatite of bone extract or osteocalcin enhanced ruffled borders and the presence of the 121F antigen on elicited giant cells. In contrast, giant cells that formed on non-resorbable materials, such as Sepharose beads, mica, and methacrylate, lacked ruffled borders and were negative for the 121F antigen. It appears that expression of the 121F osteoclast antigen correlates with the appearance and extent of ruffled membranes on giant cells. Furthermore, it appears that giant cell ruffled membrane development and the presence of the 121F osteoclast antigen are related to giant cell formation in response to resorbable materials that are subject to extracellular dissolution. Expression of this antigen may be indicative of the developmental and/or functional state of giant cells (osteoclasts) that form on resorbable substrates. In addition, components of the bone matrix, including osteocalcin, in association with bone mineral, lead to elevated levels of this osteoclast antigen.

Osteoclastic resorption of Ca-P biomaterials implanted in rabbit bone

“…Tissue response to implantation of mineralized materials seems to differ according to host species, receiving tissue and chemical composition of the implant, particularly the presence of bone proteins [36]. In this study, the results observed were similar in both types of biomaterials.…”

“…It was demonstrated that chemical composition of the implanted material influences the degree of osteoclast differentiation. The formation of mineral matrix complexes by the adsorption to hydroxyapatite of bone extract or osteocalcin enhanced ruffled border formation and the presence of specific osteoclast antigen on elicited multinucleated cells [36]. When implanted subcutaneously, synthetic crystalline apatite was reported to generate multinucleated cells showing osteoclastic features, but only when associated with osteocalcin [40].…”

“…When implanted subcutaneously in the rat or onto chorioallantoic membranes of chick embryos [36,37], devitalized mineralized or demineralized bone particles elicited the recruitment of multinucleated cells. They exhibited some phenotypic features of osteoclasts such as multinuclearity and membrane specializations (clear zones and ruffled borders), TRAP activity, inhibition of resorption by calcitonin, and presence of receptors for this hormone [7,[36][37][38][39]. In contrast, multinucleated cells recruited in subcutaneous implants of mineralized bone particles and slices in rabbits showed a TRAP activity considerably weaker than in host osteoclasts, no tartrate-resistant acid ATPase activity, and did not stain with an osteoclast-speciflc monoclonal antibody [9].…”

“…Among them, osteocalcin was hypothesized to favor differentiation of the ruffled border of the osteoclast [36,40] and osteopontin to help the binding of this cell to hydroxyapatite [41--43].…”

Ultrastructural features of odontoclasts that resorb enamel in human deciduous teeth prior to shedding

“…It is, therefore, of interest to examine the ultrastructural features of the odontoclasts that resorb enamel in order to clarify the cellular mechanism of resorption of this unique and highly mineralized substrate. Furthermore, from the view point of the interaction between clastic cells and resorbed substrates, it is also interesting to study the odontoclasts that resorb enamel, because it has been considered that some of the organic components of nonenamel mineralized substrates, which are completely lacking in enamel matrix, may be responsible for the chemotaxis (Malone et al, 1982;Mundy and Poser, 1983;Lian et al, 1984), attachment (Reinholt et al, 1990;Miyauchi et al, 1993;Ross et al, 1993), and differentiation (Krukowski and Kahn, 1982;Glowacki and Lian, 1987;Webber et al, 1990) of clastic cells.…”