Responses local host

Befus, A. D., Lee, T., Ernst, P., Egwang, T., McElroy, P., Gauldie, J. Bienenstock, J, (1986). Unique characteristics of local responses in host resistance to mucosal parasitic infections. Veterinary Parasitology, 20 175-94. 

Local invasion through the basement membrane and into the surrounding stroma is enabled by increased production of proteases by tumor cells themselves (Duffy, 1996), or by their ability to induce such a response in host stromal cells (Basset et al., 1990 Ahmad et al., 1997). Thin-walled vessels, such as newly forming capillaries or lymphatic channels, offer very little resistance to penetration by tumor cells and provide the most common pathways for tumor cell entry into the circulation. 

The second component of biocompatibility is that of material degradation. It is emphasized here that degradation is a component of biocompatibility rather than a separate phenomena. There is still confusion over this since it is often perceived that degradation, which occurs on the material side of the interface, is the counterpart to biocompatibility which is equated with the other (tissue) side. This is not correct since degradation is the counterpart to the local host response, both being contributory to the biocompatibility of the system. 

To explain this in a little more detail, let us consider the evolution of the local host response, which is the third component of biocompatibility, using a model that involves inflammatory and repair processes (7). Whenever a material is implanted into the tissues of the body, there has to be a degree of trauma associated with the insertion process. This will inevitably establish an acute inflammatory response, which is the body s natural defence mechanism to any injury. The inflammation is totally desirable and helpful since it is the precursor to the second phase of the response, which is that of tissue repair. The response to a surgical incision is acute inflammation followed by repair, the consequences of which are a zone of fibrous (collagenous) scar tissue. If a biomaterial is placed within the tissue, this response will be modified by its presence, but the extent to which that modification occurs depends on many factors. 

The effects that the material have on the tissue, the local host-response (William, 1987a) ... 

Beecher, C., Daly, M., Berry, D.P., et al. (2009) Administration of a live culture of Lactococcus lactis DPC 3147 into the bovine mammary gland stimulates the local host immune response, particularly IL-lbeta and IL-8 gene expression. J Dairy Res 76, 340-348. 

In common with other anti-inflammatory drugs aspirin modifies the response to tissue injury and infection. It is often taken for colds and viral infections, but in a controlled study there was no evidence of symptomatic benefit in rhinovirus infections. In addition, antibody-free subjects inoculated with the virus subsequently shed significantly more virus than those treated with placebo. It was suggested that aspirin interferes with the local host defence mechanisms which limit virus replication (179). 

The development of sepsis is complex and multifactorial. The normal host response to infection is designed to localize and control bacterial invasion and initiate repair of injured tissue through phagocytic cells and inflammatory mediators.1 Sepsis... 

The key factor in the development of sepsis is inflammation. Inflammation is intended to be a local and contained response to infection or injury. Infection or injury is controlled through pro- and anti-inflammatory mediators. Pro-inflammatory mediators facilitate clearance of the injuring stimulus, promote resolution of injury, and are involved in processing of damaged tissue.1,13-16 In order to control the intensity and duration of the inflammatory response, antiinflammatory mediators are released that act to regulate pro-inflammatory mediators.15-16 The balance between pro- and anti-inflammatory mediators localizes infection/injury of host tissue.13-16 However, systemic responses ensue when equilibrium in the inflammatory process is lost. 

---