The microbiome in wound repair and tissue fibrosis

Abstract

Bacterial colonization occurs in all wounds, chronic or acute and the break in epithelium integrity that defines a wound impairs the forces that shape and constrain the microbiome at that site. This review highlights the interactions between bacterial communities in the wound and the ultimate resolution of the wound or development of fibrotic lesions. Chronic wounds support complex microbial communities comprised of a wide variety of bacterial phyla, genera and species, including some fastidious anaerobic bacteria not identified using culture-based methods. Thus, the complexity of bacterial communities in wounds has historically been underestimated. There are a number of intriguing possibilities to explain these results that may also provide novel insights into changes and adaptation of bacterial metabolic networks in inflamed and wounded mucosa, including the critical role of biofilm formation. It is well accepted that the heightened state of activation of host cells in a wound that is driven by the microbiota can certainly lead to detrimental effects on wound regeneration, but the microbiota of the wound may also have beneficial effects on wound healing. Studies in experimental systems have clearly demonstrated a beneficial effect for members of the gut microbiota on regulation of systemic inflammation, which could also impact wound healing at sites outside the gastrointestinal tract. The utilization of culture-independent microbiology to characterize the microbiome of wounds and surrounding mucosa has raised many intriguing questions regarding previously held notions about the cause and effect relationships between bacterial colonization and wound repair and mechanisms involved in this symbiotic relationship.

Toll-Like Receptor Signaling in Burn Wound Healing and Scarring

“…13 The normal inflammation at the edges of full-thickness incision wounds was reduced in Tlr3 -/-mice, suggesting that doublestranded RNA (dsRNA) from damaged cells normally activates TLR3 signaling. However, Staphylococcus epidermidis lipoteichoic acid (LTA) applied to the wounds inhibited the increase in IL-6 and tumor necrosis factor (TNF)-a at the wound edge of wild-type but not Tlr3 -/-mice.…”

“…Conversely, bacterial colonization benefited wound healing in some studies (as described in 13 ), suggesting that heightened inflammation may aid in clearing necrotic debris and increasing blood flow. But these studies used rodents that are million-fold more resistant to endotoxin or bacterial loads compared to humans.…”

Innovative methods of biofilm treatment in chronic wounds

“…W skórze znajdują się komórki układu odpornościowego, stanowiące pierwszą linię obrony przed drobnoustrojami [4]. Ponadto skóra jest skolonizowana przez bakterie i grzyby tworzące florę saprofityczną [5,6]. Główne grupy bakterii kolonizujących skórę to Acinetobacteriae oraz Proteobacteriae [5].…”

Dynamic Role of Host Stress Responses in Modulating the Cutaneous Microbiome: Implications for Wound Healing and Infection

“…PAMPs include nucleic acids, lipoproteins, peptidoglycan, and lipoteichoic acid (LTA) from Gram-positive bacteria; lipopolysaccharide and flagellin from Gram-negative bacteria; and portions of fungal cell walls. 9,19 The portion of the immune system activated and how these changes are regulated differentiates a commensal organism from a potential pathogen. AMPs are fundamental components of the innate immune system that directly kill microbes by destabilization and disruption of the cellular membranes.…”