Oscillatory interstitial fluid pressure and velocity in a solid tumor with partial surface fluid leakage

Area of Science:

• Biomedical Engineering
• Mathematical Biology
• Oncology

Background:

• Solid tumors exhibit complex interstitial fluid dynamics crucial for drug delivery and disease progression.
• Understanding fluid flow and pressure within tumors is essential for developing effective therapeutic strategies.

Purpose of the Study:

• To investigate interstitial fluid flow characteristics in a spherical solid tumor with partial surface leakage.
• To analyze the impact of oscillatory microvascular pressure on pore fluid pressure and velocity.
• To compare fluid dynamics in tumors with partial leakage versus fully leaking surfaces.

Main Methods:

• Applied poroelasticity theory for small strains to model fluid behavior.
• Derived analytical solutions for pore fluid pressure and velocity within a spherical tumor model.
• Investigated the effects of varying vascular frequencies and surface leakage conditions.

Main Results:

• Partial fluid leakage at the tumor surface reduces pore pressure drop and near-surface fluid velocity compared to fully leaking surfaces.
• Both pore pressure and fluid velocity decrease significantly with increasing vascular frequency.
• At 1 Hz vascular frequency, pore pressure is two orders of magnitude smaller, and fluid velocity is one order of magnitude smaller than under steady conditions.

Conclusions:

• Partial surface leakage and oscillatory microvascular pressure substantially alter interstitial fluid dynamics in solid tumors.
• Tumor surface permeability and vascular pulsation frequency are critical factors influencing fluid transport.
• These findings provide insights into the tumor microenvironment and may inform the design of targeted therapies.