**5. Consequences of peritoneal fibrosis**

The peritoneum is an acellular, avascular layer of tissue. Significant scarring of the peritoneum is often present after 6 or more years of CAPD. Solute transport is rapid across this avascular, acellular layer and uptake into abnormal blood capillaries is rapid. However, with the loss of the interstitial cell matrix and the increase in the distance of the blood capillaries from the peritoneum, the water transport to peritoneal cavity will be nearly zero [4]. Immunolocalization of collagen 1α-1 revealed that this protein was predominantly expressed in the sub-mesothelial compact zone of EPS peritoneal samples, whereas non-EPS patients exhibited diffuse and homogeneous Col1a-1 staining.

For more advanced peritoneal conditions with potential EPS development, EPSprone states [7] is defined by (i) PD duration >3 years (ii) history of recurrent ± severe peritonitis (iii) presence of acquired UF failure or high-fast membrane transport (iv) high exposure to high GDP PD fluids, (v) repeated hemoperitoneum.
