# An In-Silico Study on the Design of Biological Controllers for Sepsis Regulation

## TL;DR

This paper uses computer modeling to design biological controllers that can regulate sepsis by influencing macrophage behavior.

## Contribution

The novel contribution is the development of IL-6-responsive feedback controllers to enhance pathogen clearance during sepsis.

## Key findings

- Simulation results showed up to 95% success in resolving sepsis using the designed controllers.
- The controllers were robust to biological variability and secondary infections.
- Macrophage-mediated regulation was identified as a critical driver of infection outcomes.

## Abstract

Macrophages are versatile innate immune cells that can
dynamically
shift between proinflammatory (M1) and anti-inflammatory
(M2) states to balance immune defense and tissue repair,
in response to local microenvironment cues. In sepsis, disrupted macrophage
function impairs this balance, reducing pathogen clearance and increasing
tissue damage. To address this, we developed a mathematical model
integrating ordinary differential equations (ODEs) and a feedback
control framework to design targeted interventions that promote healing.
Grounded in the current knowledge of immune cell behavior and signaling,
our model highlights macrophage-mediated regulation as a critical
driver of infection outcomes. With model-based analysis and a biological
understanding about the system dynamics, we designed IL-6-responsive
feedback controllers to enhance M1 macrophage-driven pathogen
clearance. Simulation results confirmed the efficacy of the controllers
in regulating the septic conditions, showing a success of up to 95%
in resolving infections when regulating multiple reactions simultaneously.
Numerical analysis further demonstrated the robustness of the controllers
to biological variabilities and the presence of a secondary infection.
We anticipate findings from this work to guide future efforts in designing
biological controllers to modulate sepsis-induced inflammation toward
a regulated and pro-resolving state.