The mouth is a true healing miracle: If it comes to injuries here, the affected mucosa renews amazingly fast. But why do wounds heal so much better in the mouth than in other parts of the body? That’s exactly what researchers have discovered. Accordingly, certain genes in the mouth are apparently read differently than in normal skin tissue – and this accelerates wound healing. this gives hope that in the future, this finding could lead to better treatment options for people with chronic and difficult-to-heal wounds.
Whether a small scratch or a larger surgical wound. If our body is injured, an amazing process begins within a few minutes. A repair team of different cells moves into the tissue and ensures that the injured areas slowly close again, the wound heals. This process works especially well in the mouth. Open bodies heal there so quickly and so well that scientists regard the mouth as the ideal type of wound healing. In contrast, wounds on the skin sometimes close very slowly or form ugly scar tissue instead of flawless replacement. So what gives the oral mucosa this extraordinary ability to regenerate?
To solve this puzzle, researcher Ramiro Iglesias-Bartolome from the National Institute of Arthritis and Musculoskeletal and Skin Diseases in Bethesda have now looked more closely at both events. They wanted to know: how is the wound healing in the mouth different from that on the skin? To do this, they recruited 30 healthy volunteers and made small wounds in their mouths and arms. Over the next six days, they observed what was happening to the wounds and at various times took tissue samples from the wounds. As expected, the oral wounds healed much faster. Already after three days, the squamous epithelium of the mucous membrane had almost completely renewed, whereas the skin wounds were still clearly visible even after six days.
RNA and molecular analyzes of the tissue samples finally revealed the reason for this. Thus, the cells in the mouth showed different gene expression patterns than those from the skin. The researchers found that the transcription factors SOX2, PITX1 and PITX2 were accelerated in the mucosa. Such DNA-binding proteins can influence whether and how strongly certain genes are interpreted. Among other things, this upregulation in the subjects’ mouths meant that the keratin-producing keratinocytes in the tissue were more active, stimulated antimicrobial defense mechanisms and, in the end, healed the wound more quickly. Interestingly enough, the transcriptional profile in the mouth was similar to that in the skin of psoriasis patients, as reported by Iglesias-Bartolome and his colleagues. For those affected by this skin disease, there is a kind of excessive wound healing.
Better wound healing thanks to gene therapy?
The new findings could one day lead to better treatment options for people with severe wounds. Thus, further experiments showed that when mice were genetically modified so that the transcription factor SOX2 was excessively active in the outermost layer of their skin, skin wounds healed faster than in control animals. “Our work contributes to a better understanding of the wound healing biology in different environments and may provide new approaches to treating chronic and non-healing wounds”.