Controlling cellular orientation, proliferation, and differentiation is valuable in designing organ replacements and directing tissue regeneration. In the present study, we developed a hybrid microfluidic system to produce a dynamic microenvironment by placing aligned PDMS microgrooves on surface of biodegradable polymers as physical guidance cues for controlling the neural differentiation of human induced pluripotent stem cells (hiPSCs). The neuronal differentiation capacity of cultured hiPSCs in the microfluidic system and other control groups was investigated using quantitative real time PCR (qPCR) and immunocytochemistry. The functionally of differentiated hiPSCs inside hybrid system's scaffolds was also evaluated on the rat hemisected spinal cord in acute phase. Implanted cell's fate was examined using tissue freeze section and the functional recovery was evaluated according to the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale. Our results confirmed the differentiation of hiPSCs to neuronal cells on the microfluidic device where the expression of neuronal-specific genes was significantly higher compared to those cultured on the other systems such as plain tissue culture dishes and scaffolds without fluidic channels. Although survival and integration of implanted hiPSCs did not lead to a significant functional recovery, we believe that combination of fluidic channels with nanofiber scaffolds provides a great microenvironment for neural tissue engineering, and can be used as a powerful tool for in situ monitoring of differentiation potential of various kinds of stem cells. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1534-1543, 2016.

The CD133(+) bone marrow cell (BMC) population includes primitive multipotent stem cells which induce neoangiogenesis. Studies suggested transplantation of these cells to infarcted myocardium can have a favorable impact on tissue perfusion and contractile performance. We assessed the feasibility, safety and functional outcomes of autologus CD133(+) BMC transplantation during coronary artery bypass grafting (CABG) in patients with recent myocardial infarction. In a prospective, nonrandomized, open-label study, 27 patients with recent myocardial infarction underwent CABG and intramyocardial injection of autologous bone marrow-derived CD133(+) cells (18 patients, BMC group) or CABG alone (9 patients, control group). At 6 months after CABG, the Wall Motion Score Index (WMSI) was significantly reduced for akinetic/dyskinetic segments treated with CD133(+) cells compared with the control group (P<0.006). Likewise, comparison between baseline and follow up results of dobutamine stress echocardiography and myocardial perfusion scintigraphy showed improvement of myocardial viability and local perfusion of the infarcted zone of the BMC group compared with the control group. No complications related to CD133(+) cell transplantation were noted, either procedurally or during postoperative at a mean of 14 months follow up. In patients with recent myocardial infarction, transplantation of CD133(+) cells to the peri-infarct zone during CABG surgery is feasible and safe, with no evidence of early or late adverse events. Moreover, these cells might restore tissue viability and improve perfusion of the infarcted myocardium, suggesting that they may induce myogenesis as well as angiogenesis.

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