The Cutaneous Microbiome and Wounds: New Molecular Targets to Promote Wound Healing

Abstract

The ecological community of microorganisms in/on humans, termed the microbiome, is vital for sustaining homeostasis. While culture-independent techniques have revealed the role of the gut microbiome in human health and disease, the role of the cutaneous microbiome in wound healing is less defined. Skin commensals are essential in the maintenance of the epithelial barrier function, regulation of the host immune system, and protection from invading pathogenic microorganisms. In this review, we summarize the literature derived from pre-clinical and clinical studies on how changes in the microbiome of various acute and chronic skin wounds impact wound healing tissue regeneration. Furthermore, we review the mechanistic insights garnered from model wound healing systems. Finally, in the face of growing concern about antibiotic-resistance, we will discuss alternative strategies for the treatment of infected wounds to improve wound healing and outcomes. Taken together, it has become apparent that commensals, symbionts, and pathogens on human skin have an intimate role in the inflammatory response that highlights several potential strategies to treat infected, non-healing wounds. Despite these promising results, there are some contradictory and controversial findings from existing studies and more research is needed to define the role of the human skin microbiome in acute and chronic wound healing.

Efficacy of Using Probiotics with Antagonistic Activity against Pathogens of Wound Infections: An Integrative Review of Literature

“…It must be stressed, however, that these animals have a thinner epidermis and dermis compared to humans, thus bringing into question suitability of such an animal model. On the other hand, experiments on large animals, such as pigs, whose skin has been regarded as the closest surrogate to human skin with regard to similarities in structure and healing, have a disadvantage of extensive costs, handling, and lack of genetic manipulability [131,135]. Certain probiotics have been reported to form robust biofilms in vitro and shown to attach to various host biofilm sites; these include L. casei, L. rhamnosus, L. plantarum, L. reuteri, L. acidophilus, B. bifidum, and B. breve [136][137][138][139][140][141].…”

Vulnerability of the industrialized microbiota

“…Sterility in skin-injury repair has been viewed as an important factor in effective wound healing. However, maintaining a sterile wound-healing environment is a difficult prospect considering the exposure of most wounds to the environment (88). Recent evidence suggests that populating wounds with commensal microbes can reduce infections after surgery and minimize the need for antibiotic treatment (89).…”

Microbiome‐skin‐brain axis: A novel paradigm for cutaneous wounds

“…Commensals can also inhibit growth of pathogens and thus alter the inflammatory response. (For a comprehensive review of skin commensal immune and microbiological interactions see). One proposed suggestion to healing wounds has been the topical application of commensal bacteria.…”

“…Inflammatory mediators are generated by multiple cell types within the wound, as the pathogen's microbial ligands activate ubiquitously expressed toll‐like receptors with downstream generation of innate immune responses . Inflammatory responses are marshalled from multiple cell types in response to bacterial ligands: mesenchymal stem cells increase IL‐6 generation, fibroblasts release TNF‐α, keratinocytes release IL‐6, TNF‐α and other pro‐inflammatory cytokines, and cells of the innate immune system exhibit a complex cross talk with the host microbiome to fine‐tune a multifaceted response (reviewed in References ).…”