Prediction of permeability-surface area product data by continuous-distribution pore models

Area of Science:

• Physiology
• Biophysics
• Biomaterials

Background:

• Microvascular transport is crucial for skeletal muscle function.
• Accurate modeling of microvascular transport is essential for understanding physiological and pathological processes.
• Previous models, like discrete-pore and fiber-matrix, have limitations in predicting experimental data.

Purpose of the Study:

• To evaluate the predictive accuracy of continuous-distribution pore models for microvascular transport in skeletal muscle.
• To compare the performance of continuous-distribution pore models against discrete-pore and fiber-matrix models.
• To determine if simple pore models can adequately characterize complex microvascular transport phenomena.

Main Methods:

• Continuous-distribution pore models (log-normal, fiber-matrix) with a water-only pathway were fitted to solute reflection coefficient (sigma) data in skeletal muscle.
• Optimal model parameters were determined using experimental data for solutes with Stokes radii from 0.5-16 nm.
• Models were then used to predict permeability-surface area product (PS) data for small solutes and proteins (0.23-3.7 nm radii).

Main Results:

• A log-normal continuous pore-size distribution model closely fit sigma data across an eight-solute, 32-fold size range.
• Both log-normal and two-discrete-pore models accurately predicted PS data for nine solutes across a 14-fold size range.
• A fiber-matrix model showed a significantly poorer fit to the sigma data compared to continuous-distribution and discrete-pore models.

Conclusions:

• Continuous-distribution pore models, specifically the log-normal and two-discrete-pore types, accurately describe experimental solute reflection and permeability-surface area product data in skeletal muscle.
• These findings suggest that complex microvascular transport processes can be effectively characterized by relatively simple pore models.
• The study validates the utility of continuous-distribution pore models for understanding skeletal muscle microvascular permeability.