Intraperitoneal pressure in peritoneal dialysis patients: a need for treatment individualization

Intra-abdominal pressure and residual renal function decline in peritoneal dialysis: a threshold-based investigation

BACKGROUND

The potential impact of elevated intra-abdominal pressure (IAP) on residual renal function (RRF) has not been determined. The objective of this study was to investigate the relationship between IAP and the rate of RRF decline in newly initiated peritoneal dialysis (PD) patients, and to identify the optimal IAP threshold value for delaying the deterioration of RRF.

METHODS

A cohort of 62 newly initiated PD patients who completed both 6- and 12-month follow-up evaluations was obtained using the Durand method. A logistic regression model was used to identify variables associated with a rapid decline in RRF. Receiver operating characteristic (ROC) curves were generated to determine the optimal threshold value. Another retrospective cohort analysis was performed to validate the identified critical value.

RESULTS

For each 1 cmH2O increase in IAP, the risk of a rapid decline in the RRF increased by a factor of 1.679. Subsequent analysis revealed that patients in the high IAP group had more significant decreases in residual renal estimated glomerular filtration rate (eGFR) (Z = -3.694, p < 0.001) and urine volume (Z = -3.121, p < 0.001) than did those in the non-high IAP group. Furthermore, an IAP ≥15.65 cmH2O was a robust discriminator for the prediction of the rate of RRF decline.

CONCLUSION

Patients in the high IAP group experienced a more rapid decline in RRF. Additionally, an optimal critical pressure of 15.65 cmH2O was identified for predicting the rate of RRF decline. IAP, as one of the factors contributing to the rapid decline in RRF in the first year of PD, should be given due attention.

Pressure induces peritoneal fibrosis and inflammation through CD44 signaling

Peritoneal dialysis (PD) is a widely used sustainable kidney replacement therapy. Prolonged use of PD fluids is associated with mesothelial-mesenchymal transition, peritoneal fibrosis, and eventual ultrafiltration (UF) failure. However, the impact of pressure on the peritoneum remains unclear. In the present study, we hypothesized increased pressure is a potential contributing factor to peritoneal fibrosis and investigated the possible mechanisms. In vitro experiments found that pressurization led to a mesenchymal phenotype, the expression of fibrotic markers and inflammatory factors in human mesothelial MeT-5A cells. Pressure also increased cell proliferation and augmented cell migration potential in MeT-5A cells. The mouse PD model and human peritoneum equilibrium test (PET) data both showed a positive association between higher pressure and increased small solute transport, along with decreased net UF. Mechanistically, we found that significant upregulation of CD44 in mesothelial cells upon pressurization. Notably, the treatment of CD44 neutralizing antibodies prevented pressure-induced phenotypic changes in mesothelial cells, while a CD44 inhibitor oligo-fucoidan ameliorated pressure-induced peritoneal thickening, fibrosis, and inflammation in PD mice. To conclude, intraperitoneal pressure results in peritoneal fibrosis in PD via CD44-mediated mesothelial changes and inflammation. CD44 blockage can be utilized as a novel preventive approach for PD-related peritoneal fibrosis and UF failure.