Heterogeneity in Peritoneal Transport during Continuous Ambulatory Peritoneal Dialysis and Its Impact on Ultraf iltration, Loss of Macromolecules and Plasma Level of Proteins, Lipids and Lipoproteins

Abstract

We investigated the effect of heterogeneity in the peritoneal transport of plasma proteins on dialysis efficiency and plasma levels of proteins, lipids and lipoproteins in 32 patients undergoing long-term continuous ambulatory peritoneal dialysis (CAPD; 9 females and 23 males, 18-76 years old). Eleven patients were studied on several occasions (at 0-42 months) and the remainder at 6-60 months on CAPD (n = 49). We have divided our patients arbitrarily into two equal groups according to their protein concentration in the peritoneal effluent at the end of an 8-hour cycle. Patients with a high peritoneal protein concentration ( ≥ 2 g/l/1.73 m²) have lower ultrafiltration capacity, higher glucose absorption rate and increased loss of most plasma proteins [including albumin, immunoglobulins (Ig), complement components and high-density lipoproteins (HDL)] compared to patients with a low peritoneal protein concentration ( < 2 g/l/ 1.73 m²). Consequently, plasma levels of albumin, IgM and HDL were lower in patients with a high peritoneal protein concentration. The latter had also increased levels of plasma triglycerides and very-low-density lipoproteins. The difference observed in peritoneal transport between the groups could be ascribed only in part to the duration of CAPD treatment, and hence to the number of peritonitis episodes but not to medications. Therefore, we suggest that inherent constitutional factors may be responsible for some of the observed heterogeneity in the peritoneal transport of these patients which is already evident at the start of CAPD treatment. Patients with high peritoneal transport are exposed to an augmented atherogenic plasma lipid profile in addition to a reduction in dialysis efficiency (ultrafiltration failure). These patients may become prone also to nutritional and immunological disturbances. Therefore, we suggest taking these effects into consideration before choosing the appropriate dialysis modality in patients with increased peritoneal transport for plasma proteins.

Role of Peritoneal Loss of Albumin in the Hypoalbuminemia of Continuous Ambulatory Peritoneal Dialysis Patients: Relationship to Peritoneal Transport of Solutes

“…and IgM levels in sera and in concentrated dialysates were measured by nephelometry [16]. The peritoneal mass transfer (D • V/T; mass/h) and clearance (D/P-V/T; ml/min) of all solutes were calculated as described previously [10,11], where Pand D are serum and dialysate concentrations of solute, and V and T are intraperitoneal dialysate volumes and dwell time intervals, respectively. Because the V/T val ues in these two equations were identical for different solutes in the same patients, we decided to delete V/T and compare peritoneal sol ute transport by D or D/P ratios.…”

“…The effects of peritoneal albumin loss and heterogeneous peritoneal solute transport on SA lev els have not been fully elucidated [11][12][13][14] and are further investigated in the present study.…”

Dyslipidemia in Chronic Kidney Disease: An Approach to Pathogenesis and Treatment

“…It is well known that CAPD patients lose substantial amount of proteins into the peritoneal dialysate, resembling the protein losses observed in NS. This protein loss may, in turn, stimulate the hepatic production of albumin and cholesterol-enriched lipoproteins thus leading to elevated concentrations of LDL-cholesterol and Lp(a) [97,98,99,100,101]. In addition, the absorption of glucose from the dialysis fluid and the resultant increase in insulin levels may enhance the hepatic synthesis and secretion of VLDL and possibly that of other lipoproteins such as Lp(a) [102].…”

Adequacy of Peritoneal Dialysis-Where Are We Going?

“…As discussed above, does a decreasing albumin concentration represent a greater risk for death than a patient with a low but stable serum albumin? Some authors have suggested that independent of dialysis dose serum albumin concentrations are inversely correlated with peritoneal membrane trans port types [46,[62][63][64], These data suggest that patients who tend to be rapid transporters have lower serum albumin levels than low transporters. Nolph et al [63] also found a lower LBM in high transporters, but no differ ence in body weight or surface area.…”

“…6). As discussed above, these patients tend to have lower albumin levels [61,62,64] despite equal doses of dialysis [63]. Perhaps, in these patients this increased glucose load during classic CAPD due to the long dwells and the need to use hypertonic fluids results in an overall decrease in appetite or a lesser propor tion of their caloric intake as protein.…”