Morphological and morphometric changes in mesothelial cells during peritoneal dialysis in the rabbit

The morphometric and morphological changes in the mesothelial cell population were studied in rabbits in peritoneal dialysis with lactate and bicarbonate buffer solution. During dialysis the mesothelial population underwent radical changes in morphology and morphometric analysis showed a significant increase in cell size. Light microscope examination showed two types of changes: hyperplasia of the mesothelial cell with diameters of up to 80 mu m, nucleus proportional to the cytoplasm, a large nucleole giving an owl's eye appearance and cytoplasm rich in granular material. The second change was multiple nuclei and arrest of cell division. Nuclear division occurred, but no separation of the cytoplasm. The cells became larger than 200 mu m, packed with nuclei and relatively little cytoplasm. Electron microscopy confirmed that the hyperplastic cells had perfect structure whereas the polynucleate cells contained vacuoles and little cytoplasmic reticulum. Immunohistochemistry using monoclonal antibodies SK2-27 and SK 60-61 specific to cytokeratins 14, 16, 17 and 8, 18, respectively, identified the cells as mesothelial. The changes were related to the glucose content of the peritoneal dialysis solution. Glucose is therefore the bioincompatible agent that modifies the mesothelium during peritoneal dialysis, causing it to become hyperplastic or blocking replication.