Immunomodulation Using Micro-bead System for Chronic Wound Healing

Abstract

Wound healing entails a series of complex stages where various cellular components of skin play a key role such as fibroblasts, keratinocytes, immune cells, endothelial cells, and extracellular matrix. The normal healing process can be divided into three distinctive phases: 1) inflammation, 2) proliferation and 3) maturation. Wounds which have failed to repair over a Period of three months are characterized as a chronic wound. In India, high costs of treatment can persuade patients from seeking proper care, which leads to the development of complex and/or chronic wounds. There are several treatments being investigated, such as stem cell therapy, delivery of bioactive compounds (e.g., growth factors, cytokines, Peptides) to the wound site by encapsulating into microbeads. Macrophages play important role in modulation of inflammatory response. Among two phenotypes of macrophage (e.g., M1 and M2), the M2 phenotype has a significant role in signalling of subsequent phases of wound healing. The aim of this project was the development of polysaccharide based microbeads, which would provide an anti-inflammatory environment to encapsulated macrophages. It was hypothesized that in presence of anti-inflammatory environment, un-activated macrophages may polarize to M2 phenotype and help in chronic wound healing by secreting anti-inflammatory cytokines and various growth factors in a sustainable and continuous manner. Pectin and polygalacturonic were chosen to develop macrophage encapsulated microbead system. Experimental results depicted that Pectin and PgA based microbeads could be used in this purpose since it was observed that these polymers are highly hemocompatible and do not have any cytotoxic effect on encapsulated cells. Encapsulated macrophages remained viable inside the beads for more than a week. Additionally, these beads promoted proliferation of macrophages. At the end morphological study showed that un-activated macrophages were polarized to M2 phenotype (macrophages attained an elongated structure) when seeded on Pectin and PgA based film. The polarization of un-activated macrophages to M2 phenotype in presence of anti-inflammatory environment inside the microbeads seems an effective strategy which might help further to treat chronic wounds within a shorter time span.