Researchers found that when stem cells from the amniotic membrane are grown in low‑oxygen conditions, they release more of the natural antimicrobial peptide LL‑37. This LL‑37‑rich fluid can kill Staphylococcus aureus bacteria in lab tests and, when applied as a gel to infected diabetic wounds in mice, it cuts bacterial numbers and speeds up healing.

Conditioned medium from amnion-derived mesenchymal stem cells (AMSCs) enhances wound healing, a process that is further improved under hypoxic culture conditions. Diabetic foot ulcers are difficult to treat and are frequently complicated by a high rate of bacterial infections, mainly Staphylococcus aureus, which can lead to limb amputation and death. Here, we topically applied conditioned medium from AMSCs cultured under hypoxic conditions to S. aureus-infected wounds in diabetic mice to investigate its effect on bacterial counts and wound healing. We prepared conditioned medium by culturing AMSCs under 21 % or 1 % O₂ and investigated its effects on S. aureus. We infected skin wounds of diabetic mice with S. aureus and treated these with hydrogels containing the conditioned medium to examine its effect on bacterial inhibition and wound healing. Conditioned medium from AMSCs cultured under 1 % O₂ contained higher levels of the antimicrobial peptide LL-37. It significantly inhibited S. aureus growth in vitro, reduced bacterial counts in infected wounds, and facilitated wound closure in diabetic mice. Hydrogels containing conditioned medium from hypoxically cultured AMSCs inhibited the growth of S. aureus and promoted wound healing in a mouse model of diabetic wounds.