Changes in Biocompatibility of Dialysis Fluid during Its Dwell in the Peritoneal Cavity

Objective To evaluate the changes in biocompatibility of peritoneal dialysis solutions during intraperitoneal dwell. Design We studied the effect of the drained dialysates at time 0 and after 30, 60, 120, 240, and 360 minutes of intraperitoneal dwell on the growth of peritoneal mesothelial cells and fibroblasts and the synthesis of proteins by these cells. On one day the patients were dialyzed with glucose-based Dianeal and on alternate days with an amino acid-containing solution based on Travasol. Patients Dialysates were collected from 4 patients during continuous ambulatory peritoneal dialysis (CAPD) training. Results Unused dialysis solutions containing glucose or amino acids inhibit growth of mesothelial cells and fibroblasts. Dialysates obtained after 30 or 60 minutes of intraperitoneal dwell support the growth of these cells in a way similar to 10% fetal calf serum, but dialysates drained after a longer dwell of 120 360 minutes had a stronger effect on growth of these cells than did serum. All glucose-based dialysates stimulate the synthesis of collagen in mesothelial cells, whereas they reduce the synthesis of non-collagen proteins. All glucose-based dialysates reduce the synthesis of collagen and noncollagen proteins in fibroblasts compared with the production of these proteins in the presence of serum. Conclusion Changes in the properties of the dialysis solutions during their intraperitoneal dwells do not seem to increase their biocompatibility. Indeed, excessive mitogenic effect and the stimulation of collagen synthesis of the dialysates may induce pathological changes in the peritoneum.

Lung growth in response to unilateral pneumonectomy in rapidly growing rats

The rapidity with which lung growth is initiated and completed after pneumonectomy was examined in young rats (4 wk of age; 82 g). After left pneumonectomy, the remaining lobes of the right lung grew to equal the weight of both lungs of control animals by day 7 and within 14 days increased from 366 to 968 mg. The tissue concentrations of RNA, DNA phosphate, collagen, and noncollagen proteins did not increase during the growth response. In contrast, total amounts of these constituents increased significantly in the remaining lung of pneumonectomized animals during the 1st postoperative wk and approached levels found in both lungs of sham-operated and unoperated controls by the end of the 2nd wk after pneumonectomy. Although cell size increased in control lungs during the experimental period, there was little evidence of additional cellular hypertrophy associated with compensatory lung growth. The character of the response to pneumonectomy in these rats was similar to that observed previously in older animals (320 g). Thus in spite of the higher basal rate of lung growth in the younger rats, the pattern and rapidity of compensation after pneumonectomy was similar in both age groups.