Tissue-resident Mesenchymal Stem Cells Research Articles

Human Tissue-Resident Stem Cells Combined with Hyaluronic Acid Gel Provide Fibrovascular-Integrated Soft-Tissue Augmentation in a Murine Photoaged Skin Model

Transplantation of adipose tissue-resident mesenchymal stem cells has been found to contribute to the establishment of a supportive fibrovascular network. The authors sought to evaluate the potential of human adipose tissue-derived stem cells to integrate with nonanimal stabilized hyaluronic acid as a novel injectable soft-tissue filler. Cell proliferation was measured by bromodeoxyuridine incorporation. Interactions of adipose tissue-derived stem cells with hyaluronic acid were documented by scanning electron microscopy. The effect of this combination on procollagen mRNA was assessed by real-time polymerase chain reaction. The potential therapeutic effects were evaluated in an athymic murine photoaged skin model by histology and by high-resolution magnetic resonance imaging. Angiogenesis was assessed by microvessel density analysis. Under in vitro culture conditions, the authors found an equal proliferation capacity of adipose tissue-derived stem cells grown on hyaluronic acid versus controls. Scanning electron microscopy showed enhanced establishment of complex microvillous networks in adipose tissue-derived stem cells adherent to hyaluronic acid compared with controls. Adipose tissue-derived stem cells and hyaluronic acid induced a significant increase in procollagen 1-alpha-2 mRNA expression compared with controls. In an athymic murine photoaged skin model, injection of this combination ablated photoinduced skin wrinkles. Magnetic resonance imaging revealed a consistent and stable volume fill by adipose tissue-derived stem cells and nonanimal stabilized hyaluronic acid at 3 weeks. Adipose tissue-derived stem cells actively incorporated into the hyaluronic acid fill and showed an organized fibrovascular network at 3 weeks. The combination of adipose tissue-derived stem cells and nonanimal stabilized hyaluronic acid holds promise as a tool with which to achieve lasting volume fill in reconstructive surgical soft-tissue augmentation.

Evidence for tissue-resident mesenchymal stem cells in human adult lung from studies of transplanted allografts

The origin and turnover of connective tissue cells in adult human organs, including the lung, are not well understood. Here, studies of cells derived from human lung allografts demonstrate the presence of a multipotent mesenchymal cell population, which is locally resident in the human adult lung and has extended life span in vivo. Examination of plastic-adherent cell populations in bronchoalveolar lavage samples obtained from 76 human lung transplant recipients revealed clonal proliferation of fibroblast-like cells in 62% (106 of 172) of samples. Immunophenotyping of these isolated cells demonstrated expression of vimentin and prolyl-4-hydroxylase, indicating a mesenchymal phenotype. Multiparametric flow cytometric analyses revealed expression of cell-surface proteins, CD73, CD90, and CD105, commonly found on mesenchymal stem cells (MSCs). Hematopoietic lineage markers CD14, CD34, and CD45 were absent. Multipotency of these cells was demonstrated by their capacity to differentiate into adipocytes, chondrocytes, and osteocytes. Cytogenetic analysis of cells from 7 sex-mismatched lung transplant recipients harvested up to 11 years after transplant revealed that 97.2% +/- 2.1% expressed the sex genotype of the donor. The presence of MSCs of donor sex identity in lung allografts even years after transplantation provides what we believe to be the first evidence for connective tissue cell progenitors that reside locally within a postnatal, nonhematopoietic organ.