Molecular charge influences transperitoneal macromolecule transport

Area of Science:

• Biomedical Engineering
• Renal Physiology
• Pharmacokinetics

Background:

• Peritoneal dialysis (PD) relies on macromolecule transport across the peritoneal membrane.
• Understanding factors influencing this transport is crucial for optimizing PD therapy.
• Molecular properties like size and charge are known to affect membrane permeability.

Purpose of the Study:

• To investigate the specific influence of molecular charge on macromolecule transport during peritoneal dialysis.
• To compare the transperitoneal transport rates of neutral, anionic, and cationic macromolecules.

Main Methods:

• Utilized fluorescent-labeled macromolecules (neutral dextran, anionic dextran sulfate, cationic diethylaminoethyl (DEAE) dextran) with radii of 15-40 Å.
• Administered macromolecules intravenously to unanesthetized rabbits, followed by peritoneal dialysis fluid instillation.
• Measured transperitoneal transport rates via dialysate to plasma concentration ratios and permeability-area product over a four-hour period.

Main Results:

• Transport rates for cationic DEAE dextran were significantly lower (P < 0.05) than for neutral dextran and dextran sulfate.
• No significant difference was observed in transport rates between neutral dextran and dextran sulfate.
• Low DEAE dextran transport was not attributed to plasma protein binding.

Conclusions:

• Molecular charge is a significant determinant of macromolecule transport across the peritoneal membrane.
• Cationic macromolecules exhibit reduced permeability during peritoneal dialysis.
• These findings have implications for designing molecules for targeted delivery or improved clearance in PD.