Study On The Relationship Between Skin Microbiome And Barrier Function

BackgroundThe skin, which locates on the surface of the human body, directly contacting withthe external environment, is an important boundary organ in anatomy and physiology.Complicated and special structure can help the skin protect our body from externalphysical and chemical assault, and prevent fluid effusion or absorbing foreign materials,at the same time also can keep body from microbes, such as bacteria, fungi, viruses,parasites and other pathogens, so it has important barrier function and protection. Skinweak acid environment, specific physiologic lipid, and defense or antimicrobialpeptides recently found in the skin can protect skin against external invasion ofpathogenic bacteria. Despite this, our skin is not sterile, but colonized by a large numberof microorganisms. Furthermore these microorganisms and different ecological nicheon skin surface form the complex ecosystems-skin microbiome. Bacteria located onthe surface of the skin can be divided into resident flora and temporary flora. Most ofthem are beneficial for us, such as cleaning up the “garbage”(apoptotic cells) on thesurface of the skin, decomposing excess lipids, resisting foreign pathogens invasionthrough the competitive inhibition, and so on. When the balance is broken, the skinfunction is disorder, so the skin disease happens. Therefore, the human microbiomeproject launched by the National Institutes of Health (NIH) has been implemented,aiming to study the characteristics and functions of the microbiome. In recent yearsmore and more dermatologist focus their attention on the skin microbiome.ObjectivesTo investigate the relationship between skin microbiome and skin barrier throughdescribe them quantitatively and qualitatively with non-invasive methods. MethodsFirst part:Thirty healthy volunteers without any disease of both sexes participated in thisstudy. Three test sites (backside, the volar forearm and the volar upper arm) wereselected for each person, and left or right sides were random chose. Then asequence of tape stripping with Corneofix were performed at each sites until30strippings had been finished. The measurement of TEWL and CAP wasperformed before the stripping (base line) and after every five strippings. Atlast, the corneofix were analysed whith VC98.Second part:100healthy female subjects were recruited. Three test sites (interdigital web,forehead and antecubital fossa) were selected for each person, and left or right sideswere random chose. Each sites marked three areas: A (2x2cm), B (2x2cm), C (1x4cm).Non-invasive detection, tape stripping and flora collection were respectivelyperformed at A, B, C area.Tape stripping and flora collection for three times with oneday interval. The specimens were stored at-20℃. The chemiluminescenceimmunodetection method and real-time quantitative PCR were used for detection ofantibacterial peptides and microbiome separately.ResultsFirst part:The value of TEWL, CAP, T/C and SESC increased with frequency of strippingand were significantly higher compared with baseline (non-strippings) on bothsites(P<0.05); Basic values of TEWL, T/C, SESC index were insignificance amongdifferent sites (P>0.05), however, the value of the back is higher than the other two siteswith the increase of the number of strips(P<0.05).Second part:1. At the forehead The TEWL value of Sa-positive group is higher than thenegative group(P<0.05)；At the antecubital fossa, the T/C values of Sa-positive group is higher than the negative group(P<0.05), the amount of sebum of Se-positive group ishigher than the negative group(P<0.05), the TEWL of MaF-positive group is higherthan the negative group(P<0.05), the TEWL and T/C values of Pse-positive group arehigher than the negative group(P<0.05); At the interdigital web, HBD2of Se-positivegroup is higher than the negative group(P<0.05).2.At the forehead, the amount andpositive rate of MaF of high barrier group is less than the low barrier group(P<0.05),the amount and positive rate of Pse of high barrier group is higher than the low barriergroup(P<0.05); At the antecubital fossa, the amount and positive rate of MaF of highbarrier group is less than the low barrier group(P<0.05); At the interdigital web, thepositive rate of Pse of high barrier group is higher than the low barriergroup(P<0.05).3.At the forehead, Se showes a negative correlation with HBD2andLL37(P<0.05), La show a negative correlation with CAP and a positive correlationwith T/C and SESC(P<0.05); At the interdigital web, there is a positive correlationbetween MaF and LL37(P<0.05), PA and TEWL(P<0.05), Pse and HBD3(P<0.05).ConclusionsThe skin microbiome, antibacterial peptide and barrier function at three sites arenot identical. Sa, as a kind of pathogenic bacteria, can damage the skin barrier leadingto increasement of TEWL, T/C value. Se is the resident bacteria of the skin, which caninduce antibacterial peptides and express soluble phenol molecules to protect the skinbarrier funcition, maintain the body homeostasis; at the time Se can indirectly affect theskin barrier through changing skin physiology: Seb. La, MaF and PA can destroy skinbarrier through different mechanism, resulting in raise of TEWL and T/C; Pse atnormal skin can induce horny cells to produce antibacterial proteins and have a protecteffect to the skin, but at poor skin may has a negative effect on the skin, evenly increaseskin damage.