Study of Hematopoietic Stem Cells in Patients with Extensive Burns

Introduction. Assessment of tissue regeneration, including that at the cellular and subcellular levels, appears to be one of the important trends in the complex treatment of patients with extensive burns. It is known that hematopoietic stem cells (HSCs) contribute to tissue restoration and regeneration through paracrine effects or direct cell differentiation, being a central component of post-burn anemia recovery and capable of forming not only blood cells, but also other types of cells. Notably, the role of these cells in burn injury has not been studied yet.
The aim of the study was to investigate in dynamics the content of hematopoietic stem cells of different phenotypes in patients with extensive burns in the process of complex treatment.
Methods. Hematopoietic stem cells and their subpopulations in peripheral blood samples were analyzed on a FACSCalibur flow cytometer (Becton Dickinson, USA) using the CellQuest program and CD45/CD34/CD38 and CD45/CD34/CD133 monoclonal antibody panels (BD, USA). The results obtained were statistically processed using the GraphPad Prism 7.0 program (USA), results were considered statistically significant at p<0.05.
Results. Hematopoietic stem cells and their subpopulations were studied at different stages of the complex treatment in 25 patients with a large burn area, ​​more than 30% of the body surface. The comparison group consisted of 15 healthy volunteers. Upon admission to the Burn Center, a group of severely burned patients revealed a significant deep deficiency of both total HSCs CD45+34+ (p=0.0002) and their subpopulations CD45dim34+38+ (p=0.019), with predominantly early precursors of hematopoiesis CD45dim34+38- (p=0.0001) and CD45dim34+133+ (p=0.0002). In the course of the complex treatment, including surgical necrectomy and autodermoplasty of burn wounds, there was observed normalization of total HSCs CD45+34+ (0.05±0.012%, p=0.031) and a subpopulation of early HSCs CD45dim34+38- (0.039±0.009%, p=0.016) in 20 days of treatment in the group of burn patients. There was a significant increase of mature CD45dim34+133- HSCs (p=0.0380) as a result of treatment, while the deficit of the more differentiated population of CD45dim34+38+ HSCs did not fully recover (p=0.272).
Conclusion. The firstly detected modulations in the content of hematopoietic stem cells of different phenotypes in patients with extensive burns may reflect the state of compensatory-adaptive reactions of hematopoiesis in the course of the complex treatment. The data obtained may support the predictive use of HSC subcellular markers to assess the regenerative potential in burn wounds healing, including that during staged surgical treatment and autodermoplasty, and to predict the development of local and general complications of burn disease.