Researchers explain why diabetes wounds heal slowly
A molecular mechanism has been found that slows wound healing in people with diabetes.Researchers from the University of Pittsburgh have shown that the reduced rate of wound healing in people with diabetes is associated with impaired function of exosomes. These are nanoscale "mediator particles" released by cells into the intercellular environment. The study opens up a new approach for treating wounds in diabetes.
Researchers collected fluid from negative pressure dressings applied to chronic wounds of 22 diabetic and 15 nondiabetic patients. In this therapy, a special dressing is placed on the wound and attached to a soft vacuum pump. Reducing the pressure below atmospheric pressure promotes wound healing by drawing out fluid and infections.
In the collected material, the researchers analyzed the fluid and isolated exosomes produced by keratinocytes, cells essential for skin repair. Exosomes from skin cells are taken up by macrophages, immune cells that coordinate wound healing.
The analysis showed that the chemical composition of substances (proteins, RNA, lipids) in exosomes from people with diabetes (diaexasomes) differed from the control group. Moreover, the total amount of such nanoparticles in the fluid obtained from the dressings in diabetic patients was lower than in nondiabetic patients.
The researchers cultured macrophages with exosomes from non-diabetic patients and diaexosomes in vitro. Analysis showed that in the former, immune cells secreted factors that help reduce inflammation and promote wound healing, while in the latter, they produced pro-inflammatory factors.
"Diexosomes cause deviations from the healing cascade, so that the resolution of inflammation is jeopardized. And this is not limited to wounds. Because exosomes are responsible for many functions in the body, diaexosomes may play a role in other diabetic complications," Chandan Sen, co-author of the study.
The scientists are investigating possible ways to restore the nanoparticles to function correctly in the bodies of diabetic patients. They are looking at two possible solutions: affecting the cells to restore the normal composition of exosomes, or isolating the cells and "loading" the missing substances to inject the particles into the wound after the changes.