Experimental study on filtrability of polymorphonuclear leukocyte suspensions

Area of Science:

• Biophysics
• Cellular Biology
• Hemodynamics

Background:

• Understanding leukocyte filtration is crucial for diagnosing inflammatory conditions and optimizing extracorporeal therapies.
• Polymorphonuclear leukocytes (PMNs) play a key role in inflammatory responses and can obstruct filtration membranes.

Purpose of the Study:

• To investigate the filtrability of polymorphonuclear leukocytes (PMNs) suspensions.
• To analyze the pressure-flow relationship and resistance during PMN filtration.
• To determine the influence of pressure differences and flow conditions on PMN plugging and dislodging.

Main Methods:

• Utilized a Nuclepore membrane filtration system to assess PMN suspension filtrability.
• Employed a gradually reduced pressure difference, with and without additional negative pressure.
• Continuously recorded the filtration process using a TV-video system for real-time data analysis.
• Measured PMN content in the filtrate and analyzed pressure-flow relations based on relative resistance.

Main Results:

• Relative resistance of PMN suspensions increased with filtered volume, approaching infinity at low pressure differences (0-2.8 cmH2O).
• Increased flow resistance was strongly correlated with PMN plugging within membrane pores.
• At higher pressure differences (5-7.8 cmH2O, 10-12.8 cmH2O), relative resistance increased to finite values with filtered volume.
• Filtration rate and PMN plugging/dislodging dynamics were dependent on applied pressure differences and flow conditions.

Conclusions:

• PMN plugging in membrane pores is the primary cause of increased filtration resistance.
• Filtration behavior is highly sensitive to pressure gradients and flow dynamics.
• Adjusting pressure and flow conditions can modulate PMN plugging and dislodging, influencing filtration efficiency.