Isolation and therapeutic potential of human haemopoietic stem cells

Characterization of a Stemness-Optimized Purification Method for Human Dental-Pulp Stem Cells: An Approach to Standardization

Human dental pulp stem cells (hDPSCs) are promising for oral/craniofacial regeneration, but their purification and characterization is not yet standardized. hDPSCs from three donors were purified by magnetic activated cell sorting (MACS)-assisted STRO-1-positive cell enrichment (+), colony derivation (c), or a combination of both (c/+). Immunophenotype, clonogenicity, stemness marker expression, senescence, and proliferation were analyzed. Multilineage differentiation was assessed by qPCR, immunohistochemistry, and extracellular matrix mineralization. To confirm the credibility of the results, repeated measures analysis and post hoc p-value adjustment were applied. All hDPSC fractions expressed STRO-1 and were similar for several surface markers, while their clonogenicity and expression of CD10/44/105/146, and 166 varied with the purification method. (+) cells proliferated significantly faster than (c/+), while (c) showed the highest increase in metabolic activity. Colony formation was most efficient in (+) cells, which also exhibited the lowest cellular senescence. All hDPSCs produced mineralized extracellular matrix. Regarding osteogenic induction, (c/+) revealed a significant increase in mRNA expression of COL5A1 and COL6A1, while osteogenic marker genes were detected at varying levels. (c/+) were the only population missing BDNF gene transcription increase during neurogenic induction. All hDPSCs were able to differentiate into chondrocytes. In summary, the three hDPSCs populations showed differences in phenotype, stemness, proliferation, and differentiation capacity. The data suggest that STRO-1-positive cell enrichment is the optimal choice for hDPSCs purification to maintain hDPSCs stemness. Furthermore, an (immuno) phenotypic characterization is the minimum requirement for quality control in hDPSCs studies.

Stem cell-based therapies for bone repair

This article provides an overview of the cellular and molecular events involved in bone repair and the current approaches to using stem cells as an adjunct to this process. The article emphasizes the key role of osteoprogenitor cells in the formation of bone and where the clinical applications of current research may lend themselves to large animal orthopaedics. The processes involved in osteogenic differentiation are presented and strategies for bone formation, including induction by osteogenic factors, bioscaffolds, and gene therapy, are reviewed.

Recombinant AAV2-mediated β-globin expression in human fetal hematopoietic cells from the aborted fetuses with β-thalassemia major

Genetic correction of autologous hematopoietic stem cells has been proposed as an attractive treatment method for β-thalassemia. Our previous study has shown that recombinant adeno-associated virus 2 (rAAV2) efficiently transduces human fetal liver hematopoietic cells, and mediates the expression of the human β-globin gene in vivo. In this study, we investigated whether rAAV2 could also mediate the expression of normal β-globin gene in human hematopoietic cells from β-thalassemia patients. Human hematopoietic cells were isolated from aborted β-thalassemia major fetuses, transduced with rAAV2-β-globin, and then transplanted into nude mice. We found that rAAV2-β-globin transduced human fetal hematopoietic cells, as determined by allele-specific PCR analysis. Furthermore, β-globin transgene expression was detected in human hematopoietic cells up to 70 days post-transplantation in the recipient mice. High-pressure liquid chromatography analysis showed that human β-globin expression levels increased significantly compared with control, as indicated by a 1.2-2.8-fold increase in the ratio of β/α-globin chain. These novel data demonstrate that rAAV2 can transduce and mediate the normal β-globin gene expression in fetal hematopoietic cells from β-thalassemia patients. Our findings further support the potential use of rAAV-based gene therapy in the treatment of human β-thalassemia.

Stem cells: From embryology to cellular therapy? An appraisal of the present state of art

ABTRACT: A series of publications has dealt in the last years with topics as the isolation, properties and applications of animal stem cells (Weissman 2000. Cell 100: 157-168; Weissman 2002. N. Engl. J. Med. 346: 1567-1579; Lovell-Badge 2001. Nature 414: 88-91; Marshak et al. 2001. Stem Cell Biology. Cold Spring Harbor Laboratory Press, New york; Eridani 2002. J. Roy. Soc. Med. 95: 5-8; Borge and Evers 2003. Cytotechnology 41: 59-68; Sgaramella 2003. Cytotechnology 41: 69-73), however, the bonanza of experimental data recently accumulating have raised such an amount of controversial views and discussions that time perhaps has come for a reassessment of the basic facts in this peculiar area of research and an evaluation of possible, not unrealistic, implications.