RESUMO
The development of various osteogenic biomaterials has not only promoted the development of bone tissue engineering but also provided more possibilities for bone defect repair. However, most previous studies have focused on the interaction of biomaterials on endogenous or exogenous stem cells involved in the bone regeneration process while neglecting the effect of changes in the immune microenvironment of bone defect sites on bone regeneration after biomaterial implantation into the host. With the development of bone immunology, the role of various immune cells, especially macrophages, in bone regeneration has gradually attracted the attention of researchers. An increasing number of studies have begun to target macrophages to better promote bone regeneration by modulating the fate of macrophages in a spatiotemporally ordered manner to mimic the changes in the immune microenvironment of bone defect sites during the natural repair process of bone tissue. Chitosan is one of the most abundant natural polysaccharides in the world. In recent years, various chitosan-based biomaterials have been widely used in macrophage fate modulation and bone regeneration. In this review, we review the interaction between macrophages and scaffold materials, general information about chitosan, the modulation of macrophage fate by chitosan-based biomaterials, and their application in bone regeneration.
RESUMO
BACKGROUND: Hypertrophic osteoarthropathy (HOA) is a rare and intricate hereditary disease. The appearance and functional deformity of the forehead caused by thickened folds are the main clinical manifestations of patients with hypertrophic osteoarthropathy. The cause of this disease is still unknown. Currently, surgical treatment has become one of the best strategies, mainly for improving the appearance of the forehead. There has been no literature report on the use of "W"-shaped skin flap resection for thickened forehead skin in patients with hypertrophic osteoarthropathy. METHODS: All cases of hypertrophic osteoarthropathy in our department in the last 7 years, and previous literature on hypertrophic osteoarthropathy, were reviewed. RESULTS: A total of 5 cases of hypertrophic osteoarthropathy in our department (mean age 21 years, all male patients) were reviewed. All patients underwent open surgery to remove the thickened skin on the forehead or the wrinkles and gyrus-shaped scalp. The jagged skin tissue was removed (8-9) cm × (1-2.5) cm × 0.5 cm. The folds and thickness of the frontal skin of the patients were greatly improved after the operation. Patient satisfaction with the treatment outcomes was unanimous. However, one case experienced a postoperative wound infection during follow-up. The utilization of the "W"-shaped excision technique allowed for the maximal removal of excessively diseased tissue, thereby facilitating a smoother resolution of the depression. CONCLUSIONS: A total of 5 cases of hypertrophic osteoarthropathy were treated in our department, and all of them underwent frontal skin "W"-shaped excision, which was safe, feasible, and practical, and the postoperative results were satisfactory. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
