ABSTRACT Background: Hematopoietic stem/progenitor cell transplantation is the main treatment option for hematological malignancies and disorders. One strategy to solve the problem of low stem cell doses used in transplantation is pre-transplant expansion. We hypothesized that using fibronectin-coated microfluidic channels would expand HSPCs and keep self-renewal potential in a three-dimensional environment, compared to the conventional method. We also compared stem cell homing factors expression in microfluidic to conventional cultures. Materials and methods: A microfluidic device was created and characterized by scanning electron microscopy. The CD133+ cells were collected from cord blood and purified. They were subsequently cultured in 24-well plates and microfluidic bioreactor systems using the StemSpan serum-free medium. Eventually, we analyzed cell surface expression levels of the CXCR4 molecule and CXCR4 mRNA expression in CD133+ cells cultured in different systems. Results: The expansion results showed significant improvement in CD133+ cell expansion in the microfluidic system than the conventional method. The median expression of the CXCR4 in the expanded cell was lower in the conventional system than in the microfluidic system. The CXCR4 gene expression up-regulated in the microfluidic system. Conclusion: Utilizing microfluidic systems to expand desired cells effectively is the next step in cell culture. Comparative gene expression profiling provides a glimpse of the effects of culture microenvironments on the genetic program of HSCs grown in different systems.

The functional significance of upregulation miR-34a in combination with albumin-bound paclitaxel nanoparticles in U251 glioblastoma cell line has been evaluated. The MTT assay determined that miR-34a and albumin-bound paclitaxel nanoparticles can reduce cell viability, but the combination of both factors has a stronger effect on cell viability. The application of qRT-PCR has demonstrated that the transduction of miR-34a could lead to exogenous upregulation of miR-34a level and downregulation of SURVIVIN. Moreover, treatment of U251 cells with miR-34a and nanoparticles together considerably inhibit SURVIVIN expression compared to miR-34a and nanoparticles alone. Flow cytometry showed that upon miR-34a overexpression cell cycle arrested in G1 phase, while treatment with nanoparticles increased the cell population in G2 phase. Upregulation of miR-34a along with treatment with nanoparticles elevated the number of cells arrested in G1/ G2 phases of the cell cycle. Expression of miR-34a with albumin-bound paclitaxel nanoparticles reduced cell viability, downregulated SURVIVIN and enhanced cell cycle arrest in G1/G2 phases. Thus, the upregulation of miR-34a with these nanoparticles are potential candidates therapeutic for glioblastoma cancer.

Abstract Microvesicles are able to induce the cell of origin’s phenotype in a target cell. MicroRNA-21, as an oncomir, is up-regulated in almost all cancer types such as leukemia which results in cell proliferation. In this study, we examine the ability of leukemia microvesicles to induce proliferation in hematopoietic stem progenitor cells (HSPCs) via microRNA-21 dysregulation. Herein, leukemia microvesicles were isolated from HL-60 and NB-4 cell lines by ultracentrifugation, and then their protein content was measured. Normal HSPCs were isolated from umbilical cord blood samples by a CD-34 antibody. These cells were treated with 20 and 40 μg/mL leukemia microvesicles for 5 and 10 days, respectively. Cell count, CD-34 analysis, and a microRNA-21 gene expression assay were done at days 5 and 10. HSPCs showed a significant increase in both microRNA-21 gene expression and cell count after treating with leukemia microvesicles compared with the control group. CD-34 analysis as stemness proof did not show any difference among the studied groups. This data suggests that HSPC proliferation followed by microRNA-21 gene over expression can be another evidence of a leukemia-like phenotype induction in a healthy target cell by leukemia microvesicles.

OBJETIVO: Investigar as propriedades de osteocondução e desempenho biológico do ácido L láctico-Poly (PLLA) com omento em defeitos ósseos. MÉTODOS: Andaimes PLLA nanofibras foram preparados via eletrofiação técnica. Cinquenta e quatro coelhos fêmeas Nova Zelândia brancos foram distribuídos aleatoriamente em três grupos de 18 coelhos cada. Defeitos criados em tíbias direitas foram preenchidos no grupo I com omento, no grupo II com PLLA nanofibras e no grupo III com a combinação do omento e PLLA. Os mesmos defeitos foram criados na tíbia esquerda de todos os grupos, mas não receberam qualquer tratamento (grupo controle). As avaliações histológicas e histomorfométricas foram realizadas em duas, quatro e seis semanas após a implantação. RESULTADOS: As alterações histológicas em todos os grupos, juntamente com o curso de tempo foram marcados e análise estatística mostrou que as pontuações médias do grupo III foram significativamente mais elevadas do que os outros grupos. CONCLUSÃO: Análise histomorfométrica da cicatrização óssea mostrou-se significativamente melhor com o PLLA combinado com omento em comparação com os outros grupos, sugerindo que este biomaterial promove a cicatrização do osso cortical, provavelmente atuando como osteocondutor.

PURPOSE: To investigate the osteoconductive properties and biological performance of Poly L-lactic acid (PLLA) with omentum in bone defects. METHODS: PLLA nanofiber scaffolds were prepared via electrospinning technique. Forty four New Zealand white female rabbits randomly divided into three groups of 18 rabbits each. Created defects in right tibias were filled in group I with omentum, in group II with PLLA nanofiber scaffold and in group III with combination of the omentum and PLLA. The same defects were created in left tibia of all groups but did not receive any treatment (control group). Histological and histomorphometric evaluations were performed at two, four and six weeks after the implantation. RESULTS: Histological changes on all groups along with the time course were scored and statistical analysis showed that the average scores in group III were significantly higher than the other groups. CONCLUSION: Histomorphometric analysis of bone healing was shown to be significantly improved by the combined PLLA with omentum compared with the other groups, suggesting this biomaterial promote the healing of cortical bone, presumably by acting as an osteoconductive scaffold.

The kidney has an inherent ability for recovery and regeneration following acute damage. However, there has been much contention as to the source of regenerating renal cells. The aim of this study was to isolate and characterize these cells. Normal rat kidneys were minced and cells were isolated with collagenase I and were cultured in an expansion medium. Adherent cells were isolated and expanded for more than 120 days in vitro. These cells had the potential of translineage differentiation into neural cells, adipocytes and osteocytes. These cells also expressed Nucleostemin, Cyclin D1, Notch1 and Survivin which are commonly expressed in stem cells. The results of the current work show that the adult kidney contains a population of multipotent stem cells.