Macrophage proteases and rheumatic diseases: regulation of plasminogen activator by thymus-derived lymphocytes

The effect of surgical suture material on osteoclast generation and implant-loosening

Background: Implant loosening - either infectious or aseptic- is a still a major complication in the field of orthopaedic surgery. In both cases, a pro-inflammatory peri-prosthetic environment is generated by the immune system - either triggered by bacteria or by implant wear particles - which leads to osteoclast differentiation and osteolysis. Since infectious cases in particular often require multiple revision surgeries, we wondered whether commonly used surgical suture material may also activate the immune system and thus contribute to loss of bone substance by generation of osteoclasts. Methods: Tissue samples from patients suffering from infectious implant loosening were collected intraoperatively and presence of osteoclasts was evaluated by histopathology and immunohistochemistry. Further on, human monocytes were isolated from peripheral blood and stimulated with surgical suture material. Cell supernatant samples were collected and ELISA analysis for the pro-inflammatory cytokine IL-8 was performed. These experiments were additionally carried out on ivory slices to demonstrate functionality of osteoclasts. Whole blood samples were incubated with surgical suture material and up-regulation of activation-associated cell surface markers CD11b and CD66b on neutrophils was evaluated by flow cytofluorometry analysis. Results: We were able to demonstrate that multinucleated giant cells form in direct vicinity to surgical suture material. These cells stained positive for cathepsin K, which is a typical protease found in osteoclasts. By in vitro analysis, we were able to show that monocytes differentiated into osteoclasts when stimulated with surgical suture material. Resorption pits on ivory slices provided proof that the osteoclasts were functional. Release of IL-8 into cell supernatant was increased after stimulation with suture material and was further enhanced if minor amounts of bacterial lipoteichoic acid (LTA) were added. Neutrophils were also activated by surgical suture material and up-regulation of CD11b and CD66b could be seen. Conclusion: We were able to demonstrate that surgical suture material induces a pro-inflammatory response of immune cells which leads to osteoclast differentiation, in particular in combination with bacterial infection. In conclusion, surgical suture material -aside from bacteria and implant wear particles- is a contributing factor in implant loosening.

The mechanism of the anticancer function of M1 macrophages and their use in the clinic

M1-type macrophages are capable of inducing lysis in various types of cancer cells, but the mechanism of action is unclear. It has been noted that an "unknown protein" produced together with protease by activated macrophages is responsible for this action. Activated M1 macrophages have been recently reported to produce family 18 chitinases, all of which have been named chitotriosidase. Our experiments have demonstrated that family 18 chitinases work together with proteases and can damage various cancer cells both in vitro and in vivo. Thus, in this article, we suggest that the 50-kDa chitotriosidase is the reported "unknown protein". In addition, we discuss how to properly stimulate activated M1 macrophages to produce 50-kDa chitotriosidases and proteases for destroying cancer cells. Because family 19 chitinase has recently been reported to kill cancer cells, we also discuss the possibility of directly using human family 18 chitotriosidase and the humanized plant family 19 chitinase for cancer treatment.

Activation of jird (Meriones unguiculatus) macrophages by the filarial parasite Brugia pahangi

Peritoneal macrophages from Mongolian jirds (Meriones unguiculatus) with either lymphatic or intraperitoneal infections of Brugia pahangi were studied to determine the effects of infection on macrophage function and morphology. Macrophages were collected at 40, 90, 140, and 200 days after inoculation of infective third-stage larvae and assayed for phagocytic and bactericidal activity by the acridine orange method and for morphological changes by light and electron microscopy. Significant increases in phagocytic and microbicidal activity (P less than or equal to 0.01) were observed in peritoneal macrophages collected from jirds with intraperitoneal infections when compared with peritoneal macrophages from jirds with lymphatic infections and resident peritoneal macrophages from normal, noninfected jirds. Morphological changes in peritoneal macrophages from jirds with intraperitoneal infections were similar to those found in thioglycolate-elicited macrophage populations. Granuloma formation was also observed in the peritoneal cavities of intraperitoneally infected jirds. The peritoneal cavity may serve as a model to study cell-worm interactions in filarial nematode infections.

A study of the effects of nabumetone (BRL 14777), a novel anti-inflammatory drug, on cell infiltration into sterile cotton pellets implanted in rats

Nabumetone a new non-steroidal anti-inflammatory drug is active in reducing the DNA content of implanted cotton pellets in rats on various dosing regimens. The effect of nabumetone can be seen during the early and late phases of the cellular reaction to the implant implicating effects upon polymorphonuclear leucocytes and monocytes. The levels of two lysosomal enzymes are reduced in the exudate by the drug treatment.

Studies on type II collagen induced polyarthritis in rats. Effect of complement depletion

The effect of cobra venom factor on the developing and the established lesion of collagen-induced rat polyarthritis has been examined. In the developing lesion, decomplementation by cobra venom factor results in a delay in the onset of inflammation and a decrease in the radiological parameters of joint destruction. Under the conditions of the decomplementation, antibody titers to collagen are not decreased. In the established lesion, treatment with cobra venom factor has no effect, on either the inflammatory lesion or the various radiological parameters of joint destruction.