Cellular Deformations under Compression in Cells Involved in Deep Tissue Injury

Deep tissue injury (DTI) is a serious lesion typically involving necrosis of skeletal muscle and fat tissues under intact skin. Currently, considerable research efforts are invested in understanding the mechanisms underlying the onset and progression of DTI. Recent studies indicated the involvement of deformation-related events at the cellular scale. Nevertheless, the specific processes at the cell level which ultimately lead to DTI are still unknown. We hypothesize that sustained deformations of soft tissues may lead to individual cell death, as a result of alteration in intracellular concentrations of cell metabolites that occur due to local plasma membrane stretches. A two-dimensional model of an adhered single generalized cell, three-dimensional models of adhered single myoblast and fibroblast, and a construct of cells embedded in ECM were developed. Finite-Element analyses of the compressed models were performed in order to study localized plasma membrane stretches. Models were compressed by a rigid plate, up to maximal global deformations of 65%, 35%, and 45%, respectively. Large deformation strain analysis was performed, and maximal local principal strains in the plasma membrane of the cells were obtained as function of the global deformation applied to the model. All models indicated that platen compression causes large tensional strains in segments of the plasma membrane. Three-Dimensional models of real cell geometry exhibited a maximal tensional strain of approximately 20%, at global cell deformation of 35%. These results support our above hypothesis, and may provide a new path in DTI research.