71. Regenerative Effects of Adipose-derived Stem Cells: A New Path in Deep Burn Treatment

PURPOSE: Worldwide, it is estimated that more than 7.1 million patients are hospitalized each year due to burn injuries. The treatment approach for burns varies depending on their depth and extent. For deep burns, several authors have analyzed the use of dermal substitutes, allografts, xenografts, and synthetic dressings, but the results have been quite variable. In that regard, a growing hypothesis suggests that the use of adipose-derived stem cells (ADSC) may be a viable alternative therapeutic approach for regenerative treatment that directly promotes tissue function and healing. This study aims to assess regenerative effects of ADSC on deep burn lesions, in an animal model. METHODS: We analyzed 36 male Wistar rats weighing 200-300g. Adipose tissue harvesting and ADSC production were performed in three animals. The rats underwent procedures to induce two third-degree burn injuries on the dorsal region. Afterward, they were randomly divided into three groups: control (C), culture medium without ADSC (CM), and culture medium with 1x106 ADSC (CM-ADSC). This randomization ensured unbiased group distribution. Both the CM and CM-ADSC groups received 0.5 mL of culture medium via intralesional injection. The animals in each group were then subdivided into three groups based on the follow-up period: 7, 14, and 28 days post-operation (PO). Sample collections from the burn injuries were performed according to these time points.We performed macroscopic analysis (healing frequency) and microscopic analysis (inflammatory cell count, arteries count, and dermal appendage count). Additionally, we assessed gene expression of the following genes: IL-1, TNF, CD-68, MMP-3, and MMP-9. RESULTS: At 28 days PO, positive healing (95%+) was observed in 20% of the control group, 50% in the CM group, and 95% in the CM-ADSC group. Histological analysis at 28 days PO revealed a 98% increase in angiogenesis in the CM-ADSC group compared to the control group (p=0.04) and a fivefold increase compared to the CM group (p=0.0005). Regarding inflammatory cell count at 14 days PO, the CM group showed a 68% reduction compared to the control group (p=0.01), while the CM-ADSC group showed an 87% reduction (p<0.001). At 28 days PO, inflammatory cell count decreased by 96% in the CM-ADSC group compared to the control group (p<0.001), by 66% in the CM group versus the control group (p=0.03), and by 91% when comparing the CM group to the CM-ADSC group (p=0.03). Intra-group gene expression analysis over time showed decreased inflammatory biomarker expression in the CM-ADSC group by 28 days PO. Both the CM and CM-ADSC groups demonstrated reduced inflammation and increased collagen biomarker expression. CONCLUSION: This study suggests that the use of ADSC as a therapeutic strategy improves the healing process on third degree burn lesions by reducing local inflammation and increasing vascularization and collagen production