Peritoneal permeability to proteins in diabetic and non-diabetic continuous ambulatory peritoneal dialysis patients

Peritoneal permeability to proteins was measured in diabetic and non-diabetic continuous ambulatory peritoneal dialysis patients during peritonitis and control periods. Clearances of albumin, transferrin, IgG, C3 and alpha 2-macroglobulin appeared to decrease as molecular weight increased. This relationship could be described by a power curve fit. The decrease was more than could be explained by differences in free diffusion only, indicating a size-selective barrier in the peritoneum. For all measured proteins clearances were higher in the diabetic patients. This may reflect a generally increased permeability due to their microangiopathy. The largest increase in protein loss and protein clearances was found during peritonitis. Our results do not suggest increased local production of any of the investigated proteins during the inflammation. Therefore, an increase in either peritoneal permeability or effective surface area or both is the most likely explanation. It is concluded in this study that peritoneal protein clearances are dependent on their molecular weight and that they are proportionally increased in patients with diabetes and during peritonitis.