Impaired intestinal barrier function measured by differently sized polyethylene glycols in patients with chronic renal failure.

The intestinal mucosa plays a fundamental role as the site for absorption of nutrients, and as an important barrier from potentially harmful agents in the intestinal lumen. Little is known of the permeability properties of the intestinal mucosa in uraemic patients. The intestinal permeability to differently sized polyethylene glycols (PEGs; range 326-1254 daltons) was studied in nine patients with chronic renal failure (24 hour endogeneous creatinine clearance 5-24 ml/minute). The maximum 24 hour urinary recovery of PEGs was decreased in the uraemic patients but relatively more of the larger than the smaller PEGs were found in these patients. The results suggest a reduced urinary recovery of PEGs caused by renal dysfunction but also a relatively increased intestinal permeability to larger PEGs in the uraemic patients.