Zhaodi Gong | PubMed Health

PubMed2006

Blood vessels engineered from human cells.

Human vascular tissue engineering has progressed substantially over the past decade. Issues remain as to the optimum culture scaffold and cell source that should be used for arterial regeneration. In addition, limitations in replicative life span of adult human cells as compared with young animal cells have made human vascular tissue engineering more challenging. Despite these obstacles, several strategies for generating replacement vessels have progressed to clinical trials.

Age Factors↗

PubMed2004

Inhibitory effect of alcohol on osteogenic differentiation in human bone marrow-derived mesenchymal stem cells.

BACKGROUND: Alcohol-induced osteoporosis is characterized by a considerable suppression of osteogenesis. The objective of this investigation was to determine the effect of alcohol on gene expression, protein synthesis, and mineralization in human bone marrow-derived mesenchymal stem cells induced toward osteogenic differentiation in vitro. METHODS: Human bone marrow-derived mesenchymal stem cells induced toward osteogenesis were cultured in the presence or absence of 50 mM alcohol. Stem cells were characterized by using SH2 antibody to the cell-surface antigen CD105/endoglin, and their proliferation in the presence of alcohol was quantified. The expression of genes for early, middle, and late markers of the osteogenic lineage was quantified by Northern analysis, and bone matrix protein synthesis was assayed. The effect of alcohol on cell-mediated matrix mineralization in terminally differentiated cultures was determined by von Kossa staining. RESULTS: Fluorescence-activated cell sorting analysis of human mesenchymal stem cells separated with a Percoll gradient proved 99% homogeneity by using SH2 antibody to the surface antigen CD105. Dose-dependent inhibition of proliferation of these stem cells occurred at concentrations greater than 50 mM alcohol. Gene expression of osteoblast-specific factor 2/core binding factor a1 (Osf2/Cbfa1), type I collagen, alkaline phosphatase, and osteocalcin (early, middle, and late markers for osteogenesis, respectively) was analyzed with and without osteogenic induction and treatment with 50 mM alcohol. After induction, Osf2/Cbfa1 levels were unresponsive to alcohol. To determine the effect of alcohol on human mesenchymal stem cell progression along the osteogenic pathway, messenger RNA (mRNA) levels for type I collagen, alkaline phosphatase, and osteocalcin were examined after osteogenic induction. After osteogenic induction, alcohol down-regulated the gene expression of type I collagen and significantly reduced its synthesis. Alcohol did not alter mRNA expression of alkaline phosphatase, a midstage marker for osteogenesis, but significantly decreased its activity compared with osteogenic induction alone. After induction, osteocalcin remained unchanged by alcohol at both the mRNA and protein levels. Histochemistry revealed decreased alkaline phosphatase staining and fewer alkaline phosphatase-positive cells in alcohol-treated human mesenchymal stem cell cultures. von Kossa staining revealed a reduction in the number of mineralizing nodules in stem cell cultures after alcohol treatment. CONCLUSIONS: Collectively, the data suggest that alcohol alters osteogenic differentiation in human bone marrow-derived mesenchymal stem cell cultures during lineage progression and provide further insight into alcohol-induced reduced bone formation.

Adult↗

PubMed2004

Adipogenic effect of alcohol on human bone marrow-derived mesenchymal stem cells.

BACKGROUND: In addition to a decrease in bone mass in alcoholics their osteopenic skeletons show an increase in bone marrow adiposity. Human bone marrow mesenchymal stem cells (hMSC) in vivo differentiate into several phenotypes including osteogenic and adipogenic cells, both of which remain as resident populations of bone marrow. In vitro, the lineage commitment and differentiation of hMSC toward the adipogenic pathway can be promoted by alcohol. METHODS: Human male and female mesenchymal stem cells from joint replacement surgery were cultured. Cells were grouped as: 1) Control (no additions to the culture medium), 2) EtOH (50 mm alcohol added to the culture medium), 3) OS (osteogenic inducers added to the culture medium), and 4) OS + EtOH (osteogenic inducers and 50 mm alcohol added to the culture medium). Cultures stained with Nile Red confirmed the development of differentiated adipocytes. Population analysis was performed using fluorescence-activated cell sorting. Gene expression of early, middle, late, and terminal differentiation stage markers (PPAR)gamma2, lipoprotein lipase, adipsin, leptin, and adipocyte P2 (aP2)] was studied by Northern hybridization, and protein synthesis of aP2 was determined by Western analysis. RESULTS: Nile red staining confirmed increased adipocyte development 10 days after the onset of treatment with 50 mm alcohol and osteogenic induction. By day 21 the number of adipocytes increased to 13.6% of the total population. Alcohol up-regulated the gene expression of PPARgamma2 whereas no up-regulation was observed for the other genes. Protein production of aP2 was significantly increased in hMSC cells by culture in the presence of alcohol. CONCLUSIONS: The data suggest that alcohol's adipogenic effect on cultured hMSC is through up-regulation of PPARgamma2 at the point of lineage commitment as well as through enhancement of lipid transport and storage through increased aP2 synthesis. The alcohol-induced expression and synthesis changes account for the increased Nile red staining of cultured hMSC.

Adipocytes↗