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Experimental study on filtrability of polymorphonuclear leukocyte suspensions
1National Cardiovascular Center Research Institute, Osaka, Japan.
Abstract:
Filtrability of a suspension of polymorphonuclear leukocytes (PMNs) was examined in a Nuclepore membrane filtration system utilizing a gradually reduced pressure difference with or without an additional negative pressure. The filtration process was continuously recorded using a TV-video system for data analysis. The PMN content in the filtrate was directly measured. The pressure-flow relation was analyzed in terms of the relative resistance of the PMN suspension to that of the suspending medium. The relative resistance of the PMN suspension increased with an increase in the filtered volume until it approached infinity at the level of low pressure difference (2.8 - 0 cmH2O). The remarkable increase in flow resistance was closely associated with the plugging of PMNs in the membrane pores. At high pressure differences (12.8 - 10 cmH2O, 7.8 - 5 cmH2O), the relative resistance increased up to finite values, as the filtered volume increased. The variation in the relative resistance was greatly dependent upon the pressure difference or the flow condition. The amount of filtered cell fraction increased with an increase of additional pressure, indicating that the relative resistance was changed according to the rate of PMN plugging and dislodging in the pores of the membrane.
Insights
Polymorphonuclear leukocytes (PMNs) filtration resistance increases with volume, especially at low pressures, due to pore clogging. Flow conditions significantly impact this resistance, affecting cell filtration.
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.