Disruption of the skin by acne infection, infection, sun damage, disease, injury due to trauma, surgery, burns, accidents, or by chemical, dermabrasion or laser procedures employed for skin rejuvenation, creates a signal to the innate immune system and initiates responses that may or may not be efficient in a) avoiding an impending invasion from surrounding microbes and b) in starting the production of new healthy cells to replace those injured.
Dermal defense mechanisms by antimicrobial peptides
Braff MH, Bardan A, Nizet V, Gallo RL. San Diego, California, USA.
Anti-microbial peptides are mainly tiny cationic polypeptides that are grouped together due to their capacity to impede the multiplication of microbes.
As effects of innate immunity, antimicrobial peptides quickly destroy a wide spectrum of bacteria, fungi, and viruses. In addition, these peptides alter the local inflammatory reaction and trigger systems of cellular and adaptive immunity. Cathelicidins and defensins include the most important families of antimicrobial peptides in the dermis, although other dermal peptides, such as proteinase inhibitors, chemokines, and neuropeptides also express antimicrobial effects.
Together, these useful antimicrobial peptides have a vital role in skin immune defense and disease pathogenesis.
Antimicrobial Peptides in the Skin: Biological Relevance
Antimicrobial peptides, which are produced in the dermis at sites of potential microbial entry, supply a soluble barrier that acts as an impediment to infection. In the case of infection or wound, antimicrobial peptide presence in the dermis is upregulated due to augmented production by keratinocytes and accumulation from degranulation of recorded neutrophils. Although antimicrobial peptides actually show in vitro antimicrobial action, studies have revealed that many peptides, including cathelicidins and defensins, are deactivated by physiological salt concentrations (Goldman et al., 1997).
In fact, a recent research has revealed that mammalian dermis has a fundamental antimicrobial-enhancing factor that turns bacterium susceptible to cathelicidin in vitro, despite the presence of physiological salt and serum (Dorschner et al., 2004). The in vivo relevancy of antimicrobial peptides in the physiological environment is further accentuated by the laboratory animal models and human dermal ailments.
Biological immune defense function is highly improved by a soluble antimicrobial peptide barrier that is started when physical barriers fail to avoid microbial entry.
The skin not only acts as a mechanical barrier against microbes, it also produces peptides which tend to show broad-spectrum antimicrobial action. The skin also produces growth factors, inhibitors of tumors and proteins. Following skin damage or wounds, growth factors are secreted to stimulate the rejuvenation of tissue and to induce the synthesis of antimicrobial peptides. The growth factor response ceases after rejuvenation of the tissue, when the physical barrier defying microbial invasions is re-established.
Source by Kathleen LeRoi