Membrane longevity in peritoneal dialysis: impact of infection and bio-incompatible solutions

As experience with peritoneal dialysis (PD) has improved and peritonitis rates have decreased, more patients are surviving for long periods on PD. Associated with this has been the recognition that there are unique complications of PD, specifically sclerosing syndromes and membrane failure that are most common in the long-term patient. Although anecdotal data would suggest that the long-term exposure to "bio-incompatable" fluids and or the occurrence of severe episodes of peritonitis are contributory in the pathogenesis of these diseases, cause and effect have not been proven. Normal peritoneal structure, changes that occur over time, and how the normal resident immune defense systems are altered with PD are reviewed. It is known that the continued loss of macrophages in the PD fluid results in an ever increasing percentage of immature cells in the peritoneum, which paradoxically are more reactive in terms of cytokine generation and less effective in host defense. The potential harmful effects of glucose and advanced glycosylation end products are also explored. The review concludes stating that further research is needed to better link the clinical syndromes with alterations in membrane structure/function.