Protein-Losing Enteropathy is Associated with Peritoneal Functional Abnormalities in Peritoneal Dialysis Patients

Abstract

Objective

To evaluate the relationship between acquired peritoneal transport disorders and the presence of protein-losing enteropathy (PLE), and their contribution to the protein malnutrition in peritoneal dialysis (PD) patients.

Patients and Methods

We studied 31 clinically stable PD patients that received a fat overload diet for 3 days. We measured intestinal absorption of fecal fat (normal < 6 g/24-hour stool) and nitrogen (normal < 2 g/24-hr stool), intestinal protein permeability [fecal clearance of α₁-antitrypsin (Cα₁AT) (normal < 12 mL/24-hr stool)], and nutritional markers [normalized protein nitrogen appearance (nPNA), half-life medium-term proteins, and body mass index]. Peritoneal solute transport was measured by mass transfer coefficient (MTC), and water transport by peritoneal ultrafiltration (UF) capacity. To define protein maldigestion it was necessary to find high fecal nitrogen values with normal Cα₁AT; PLE was defined when both values were elevated.

Results

High fecal nitrogen (mean 2.1 ± 1 g/24-hr stool) and fat (mean 5.8 ± 3.6 g/24-hr stool) were found in 15 patients; 6 patients had high Cα₁AT levels (PLE). These 6 patients showed a worse nutritional status: lower albumin (3.57 ± 0.57 g/dL vs 3.98 ± 0.38 g/dL, p < 0.05) and transferrin (243 ± 70 mg/dL vs 272 ± 44.3 mg/dL, p < 0.05), as well as lower triglycerides (131.3 ± 31.7 mg/dL vs 187 ± 116 mg/dL, p < 0.05). Higher urea MTCs were found in 10 patients, normal in 7, and lower in 14. Higher creatinine MTCs were found in 8 patients, normal in 15, and lower in 8. Normal peritoneal UF capacity was found in 25 and lower in 6 patients. These 6 patients showed higher urea and creatinine MTCs and Cα₁AT. A positive linear correlation between Cα₁AT, urea MTC (r = 0.56, p < 0.01), and creatinine MTC (r = 0.46, p < 0.01) was found. A similar situation occurred between Cα₁AT, fecal fat (r = 0.45, p < 0.05), and fecal nitrogen (r = 0.43, p < 0.05). Thirteen patients with previous history of peritonitis showed higher Cα₁AT than those without peritonitis (10.2 ± 8 mL/24-hr stool vs 5.2 ± 4.4 mL/24-hr stool, p < 0.05).

Conclusions

We confirm that protein and fat malabsorption, maldigestion, and PLE are present in some PD patients. Higher fecal Cα₁AT is associated with malnutrition and poorer showings of the viability markers of peritoneal membrane function.