Foreign-body response macrophages

A possible technique adopted to prevent fibrous capsule formation around the implant is the addition of a tissue intermediary [203,204]. Indeed, if this material has a continuous, interconnected, porous structure (pore diameter >8-10 p-m), macrophages are capable of invading structure voids. Consequently, vascularized tissue can grow in the implant and the foreign body response is avoided as this porous stmcture is able to mimic extracellular matrix. The first example of intermediary tissue use concerns the coating of an implanted catheter by means of a silicone mbber cage [205]. Typically,... 

A murine monocytes-macrophages cell line was used as a model to study foreign-body response and phagocytosis capability. The adhesion and proliferation of these cells increased after alkaline surface hydrolysis of P3HB-8%3HV films. Pretreatment of the unmodified polymer with collagen had a repulsive effect on the cells, which disappeared on the hydrolyzed polymer, while fibronectin promoted cell adhesion on both siu-faces [122]. 

The mechanism of action of talc in pleurodesis has not been fully elucidated, although it is thought to stimulate a typical local inflammatory response, with reduced fibrinolytic activity, mesothelial cell injury, and fibroblast proliferation. Pneumonitis or respiratory failure can be secondary to downstream inflammatory mediators from more proximal talc injury (7). This acute-phase inflammatory response is dose-related (8,9) and is inhibited by glucocorticoids (10). Talc may also have an adhesion stimulating quality, since empyema alone stimulates a typical inflammatory response but does not lead to pleurodesis (11). In fact, talc stimulates intercellular adhesion molecule-1 in mesothelial cells (12). The mechanism of chronic fibrosis may involve continuous fibroblast activation by foreign body giant cell released mediators or macrophages. 

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