The importance of both fibroblasts and keratinocytes in a bilayered living cellular construct used in wound healing.

Cross talk between fibroblasts and keratinocytes, which maintains skin homeostasis, is disrupted in chronic wounds. For venous leg ulcers and diabetic foot ulcers, a bilayered living cellular construct (BLCC), containing both fibroblasts and keratinocytes that participate in cross talk, is a safe and effective product in healing chronic wounds. To show the importance of both cell types in BLCC, constructs were generated containing only fibroblasts or only keratinocytes and compared directly to BLCC via histology, mechanical testing, gene/protein analysis, and angiogenesis assays.

Human palatine tonsil: a new potential tissue source of multipotent mesenchymal progenitor cells.

Introduction: Mesenchymal progenitor cells (MPCs) are multipotent progenitor cells in adult tissues, for example, bone marrow (BM). Current challenges of clinical application of BM-derived MPCs include donor site morbidity and pain as well as low cell yields associated with an age-related decrease in cell number and differentiation potential, underscoring the need to identify alternative sources of MPCs. Recently, MPC sources have diversified; examples include adipose, placenta, umbilicus, trabecular bone, cartilage, and synovial tissue.

A non-contact suspension culture approach to the culture of osteogenic cells derived from a CD49elow subpopulation of human bone marrow-derived cells.

We demonstrate that adult human bone marrow (BM) contains a population of mesenchymal stromal cells (MSCs) that can be expanded in non-adherent, cytokine-dependent, suspension culture conditions for at least 42 days. The cells generated during suspension culture lacked detectable levels of gene expression associated with differentiated mesenchymal cell types, including bone, muscle and fat, suggesting that suspension culture maintains MSCs in an uncommitted state. However, when these undifferentiated cells were taken out of suspension culture and placed in adherent osteogenic conditions, osteogenic genes were upregulated and morphologically identifiable bone matrix was elaborated.

Cross-talk between Wnt signaling pathways in human mesenchymal stem cells leads to functional antagonism during osteogenic differentiation.

Wnt signaling is involved in developmental processes and in adult stem cell homeostasis. This study analyzes the role(s) of key Wnt signaling mediators in the maintenance and osteogenesis of mesenchymal stem cells (MSCs). We focus specifically on the involvement of low-density lipoprotein-related protein 5 (LRP5), T-cell factor 1 (TCF1), and Frizzled (Fz) receptors, in the presence or absence of exogenous, prototypical canonical (Wnt3a), and non-canonical (Wnt5a) Wnts.

Canonical and non-canonical Wnts differentially affect the development potential of primary isolate of human bone marrow mesenchymal stem cells.

This study examines the role of Wnt signaling events in regulating the differential potential of mesenchymal stem cells (MSCs) from adult bone marrow (BM). Immunohistochemical analysis of BM revealed co-localization of Wnt5a protein, a non-canonical Wnt, with CD45(+) cells and CD45(-) STRO-1(+) cells, while Wnt3a expression, a canonical Wnt, was associated with the underlying stroma matrix, suggesting that Wnts may regulate MSCs in their niche in BM. To elucidate the role of Wnts in MSC development, adult human BM-derived mononuclear cells were maintained as suspension cultures to recapitulate the marrow cellular environment, in serum-free, with the addition of Wnt3a and Wnt5a protein.

Comparison of proliferative and multilineage differentiation potential of human mesenchymal stem cells derived from umbilical cord and bone marrow.

Human umbilical cord perivascular cells (HUCPVCs) have been shown to have a high proliferative potential and the capacity to differentiate into an osteogenic phenotype. HUCPVCs have thus been considered a possible extra-embryonic mesenchymal stem cell (MSC) source for cell-based therapies. To assess this potential, we compared HUCPVCs to the "gold standard" bone marrow mesenchymal stromal cells (BMSCs) with respect to their proliferation, differentiation, and transfection capacities.

Soluble factor cross-talk between human bone marrow-derived hematopoietic and mesenchymal cells enhances in vitro CFU-F and CFU-O growth and reveals heterogeneity in the mesenchymal progenitor cell compartment.

The homeostatic adult bone marrow (BM) is a complex tissue wherein physical and biochemical interactions serve to maintain a balance between the hematopoietic and nonhematopoietic compartments. To focus on soluble factor interactions occurring between mesenchymal and hematopoietic cells, a serum-free adhesion-independent culture system was developed that allows manipulation of the growth of both mesenchymal and hematopoietic human BM-derived progenitors and the balance between these compartments. Factorial experiments demonstrated a role for stem cell factor (SCF) and interleukin 3 (IL-3) in the concomitant growth of hematopoietic (CD45+) and nonhematopoietic (CD45-) cells, as well as their derivatives.

Human umbilical cord perivascular (HUCPV) cells: a source of mesenchymal progenitors.

We describe the isolation of a nonhematopoietic (CD45-, CD34-, SH2+, SH3+, Thy-1+, CD44+) human umbilical cord perivascular (HUCPV) cell population. Each HUCPV cell harvest (2-5 x 10(6), depending on the length of cord available) gave rise to a morphologically homogeneous fibroblastic cell population, which expressed alpha-actin, desmin, vimentin, and 3G5 (a pericyte marker) in culture. We determined the colony-forming unit-fibro-blast (CFU-F) frequency of primary HUCPV cells to be 1:333 and the doubling time, which was 60 hours at passage 0 (P0), decreased to 20 hours at P2.

Adult human bone marrow-derived mesenchymal progenitor cells are capable of adhesion-independent survival and expansion.

Overview: We show the existence of adult human mesenchymal progenitor cells (hMPCs) that can proliferate, in a cytokine-dependent manner, as individual cells in stirred suspension cultures (SSC) while maintaining their ability to form functional differentiated mesenchymal cell types.

Materials And Methods: Ficolled human bone marrow (BM)-derived cells were grown in SSC (and adherent controls) in the presence and absence of exogenously added cytokines. Phenotypic, gene expression, and functional assays for hematopoietic and nonhematopoietic cell populations were used to kinetically track cell production.