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Kkot Nim Kang,
Ju Young Lee,
Da Yeon Kim,
Bit Na Lee, Hyun Hee Ahn,
Bong Lee,
Gilson Khang,
So Ra Park,
Byoung Hyun Min,
Jae Ho Kim,
Hai Bang Lee,
Moon Suk Kim
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ABSTRACT: Using a complete spinal cord transection model, the present study employed a combinatorial strategy comprising rat bone marrow stem cells (rBMSCs) and polymer scaffolds to regenerate neurological function after spinal cord injury (SCI) of different lengths. SCI models with completely transected lesions were prepared by surgical removal of 1 mm (SC1) or 3 mm (SC3) lengths of spinal cord in the eighth-to-ninth spinal vertebrae, a procedure that resulted in bilateral hindlimb paralysis. A cylindrical poly(D,L-lactide-co-glycolide)/small intestinal submucosa scaffold 1 or 3 mm in length with or without rBMSCs was fitted into the completely transected lesion. Rats in SC1 and SC3 groups implanted with rBMSC-containing scaffolds received Basso-Beattie-Bresnahan scores for hindlimb locomotion of 15 and 8, respectively, compared with ∼3 for control rats in SC1-C and SC3-C groups implanted with scaffolds lacking rBMSCs. The amplitude of motor-evoked potentials recorded in the hindlimb area of the sensorimotor cortex after stimulation of the injured spinal cord averaged ∼100 μV in SC1-C and 10-50 μV in SC3-C groups at 4 weeks, and then declined to nearly zero at 8 weeks. In contrast, the amplitude of motor-evoked potentials increased from ∼300 to 350 μV between 4 and 8 weeks in SC1 rats and from ∼200 to ∼250 μV in SC3 rats. These results demonstrate functional recovery in rBMSC-transplanted rats, especially those with smaller defects. Immunohistochemically stained sections of the injury site showed clear evidence for axonal regeneration only in rBMSC-transplanted SC1 and SC3 models. In addition, rBMSCs were detected at the implanted site 4 and 8 weeks after transplantation, indicating cell survival in SCI. Collectively, our results indicate that therapeutic rBMSCs in a poly(D,L-lactide-co-glycolide)/small intestinal submucosa scaffold induced nerve regeneration in a complete spinal cord transection model and showed that functional recovery further depended on defect length.
Tissue Engineering Part A 06/2011; 17(17-18):2143-52. · 4.64 Impact Factor
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Na Ri Kim,
Seung Kyu Kang, Hyun Hee Ahn,
Sung Wook Kwon,
Woul Seong Park,
Ki Suk Kim,
Sung Soo Kim,
Hee Jung Jung,
Sang Un Choi,
Jin Hee Ahn,
Kwang Rok Kim
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ABSTRACT: A new synthetic small molecule, compound 1, which induced a neuronal differentiation from mesenchymal stem cells (MSCs) with an excellent efficiency, was identified. Furthermore the differentiated cell by 1 showed the neural electrophysiological and cholinergic neuron properties.
Journal of Medicinal Chemistry 12/2009; 52(24):7931-3. · 4.80 Impact Factor
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Molecular BioSystems 07/2009; 5(6):609-11. · 3.53 Impact Factor
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ABSTRACT: The sol-to-gel transition occurring at around body temperature makes the MPEG-PCL diblock copolymer an ideal candidate material for use as an injectable in situ-forming gel containing human adipose tissue-derived stem cells (hADSCs). The sol can be prepared at room temperature, and the gel forms at body temperature. Solutions of the copolymer containing hADSCs and osteogenic factors injected into rats formed gel scaffolds at the injection sites. The gels thus formed showed the interconnective pore structure required to support growth, proliferation, and differentiation of hADSCs. Bromodeoxyuridine-labeled hADSCs were confirmed to be present in gels formed in vivo. Bone formation was observed only in gel implants containing both hADSCs and osteogenic factors. Subcutaneous implantation of the in situ-forming gel scaffold demonstrated that hADSCs embedded in the gel stimulated much lower host tissue responses than did the gel alone, probably because of the unique immunomodulatory properties of hADSCs. In conclusion, our data on hADSCs embedded in an in situ gel scaffold suggest that this formulation may provide numerous benefits as a noninvasive alternative for tissue-engineered bone formation.
Tissue Engineering Part A 02/2009; 15(7):1821-32. · 4.64 Impact Factor
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ABSTRACT: We herein examined the bone formation from rat muscle-derived stem cells (rMDSCs) using an injectable in situ-forming chitosan gel in vivo. The rMDSCs were easily isolated from rat muscle tissue. The osteogenic factors caused differentiation of rMDSCs toward the osteogenic lineage. The rMDSCs survived well on the scaffold created by the in vitro and in vivo in situ-forming chitosan gel, indicating that in situ gel-forming chitosan was a suitable substrate for the attachment and proliferation of rMDSCs. Bone formation was observed only in chitosan gel containing both rMDSCs and osteogenic factors. Subcutaneous implantation of the in situ-forming chitosan gel demonstrated that rMDSCs-containing chitosan gel induced much lower host tissue responses than did the chitosan gel alone, probably due to the immunosuppression of the transplanted rMDSCs.
Biomaterials 12/2008; 29(33):4420-8. · 7.40 Impact Factor
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ABSTRACT: In this study, we examined the use of polyethyleneimine (PEI) as a non-viral gene carrier and lipofectamine(trade mark) 2000 as control for rat pheochromocytoma PC-12 cells. The complex formation of PEI and DNA or lipofectamine and DNA was characterized by gel electrophoresis and measurement of particle size and surface charge. A gradual increase in surface charge (from 0.7 to 43 mV) and a gradual decrease in particle size (from 900 to 130 nm) was observed in the PEI-DNA complex with higher PEI concentrations. The cytotoxicity of PC-12 cells for lipofectamine-DNA complex was similar to PEI-DNA complex at N:P charge ratios of 4 and 8. Transfection efficiency was 14% for lipofectamine and 15% for PEI. At low N:P ratio, DNA condenses poorly, so the particle size tends to be large and polydispersed, resulting in poor transfection efficiency. Meanwhile, a high N:P ratio results in high transfection efficiency and cytotoxicity. Transfected PC-12 cells showed the generation of neurites from transfected PC-12 cells in the presence of NGF, indicating the differentiation of PC-12 cells. NGF-differentiated PC-12 cells were transfected by PEI-DNA complex of N:P charge ratio 8. From real-time imaging for transfection, the enhanced green fluorescent protein (EGFP) started to localize in the nuclei of PC-12 cells at 5 h and localized in the cytoplasm from 15 h. Our study demonstrates that PEI or lipofectamine may be applied as an effective gene carrier for PC-12 cells.
Journal of Tissue Engineering and Regenerative Medicine 08/2008; 2(5):288-95. · 3.28 Impact Factor
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ABSTRACT: We herein formulated and characterized an in situ-forming chitosan gel consisting of chitosan and glycerol phosphate (GP) disodium salt, and examined its use as an in vivo scaffold for rat bone marrow mesenchymal stem cells (rBMSCs). First, the phase transition behaviors of chitosan solutions formulated with and without GP were characterized as a function of temperature. Chitosan solutions containing > 20 wt % GP became a gel at 37 degrees C and maintained this form for 28 days in vitro and in vivo. Next, we examined whether the chitosan gel could act as a suitable biocompatible substrate for the attachment and proliferation of rBMSCs. Immunohistochemistry clearly demonstrated that rBMSCs survived well on the scaffold created by in situ-forming chitosan gel in rats. Injection of chitosan gel alone induced macrophage accumulation in the host tissue and at the edge of the chitosan, whereas injection of chitosan gel containing rBMSCs was associated with decreased macrophage accumulation, indicating immunosuppression by the transplanted rBMSCs. Our results collectively show for the first time that chitosan gel could serve as an in situ-forming gel scaffold for entrapped rBMSCs in vivo.
Tissue Engineering Part A 07/2008; 14(6):1099-108. · 4.64 Impact Factor
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ABSTRACT: In this study, we examined the use of polyethyleneimine (PEI) as a carrier for gene delivery in human adipose tissue-derived stem cells (hADSCs). These multipotent cells can form bone, cartilage, adipose, and other connective tissues. In primary culture, hADSCs are fibroblastic in appearance in primary culture, and they show a high rate of proliferation for at least five passages. Immunophenotyping showed that these cells are positive for the mesenchymal stem cell markers CD29 and CD44 but negative for the hematopoietic cell surface markers CD34, CD45, and c-kit. PEI and Lipofectamine were compared as gene carriers for hADSCs. DNA completely bound PEI at a negative-to-positive (N/P) charge ratio of 4. The PEI-DNA complexes were spherical with smooth surfaces. As the proportion of PEI was increased, the size of the PEI-DNA complexes decreased from 990 to 130nm, the positive surface charge decreased, and the cytotoxicity increased. Flow cytometry revealed that the transfection efficiency using PEI at N/P charge ratios of 4 and 8 was higher than that of Lipofectamine. The highest transfection efficiency (19%) was obtained at an N/P charge ratio of 8. After transfection, the enhanced green fluorescent protein (EGFP) started to localize in the nuclei of hADSCs at 4h 30m and localize over cytoplasm from 9h 30m. In conclusion, PEI acts as an effective gene carrier for hADSCs.
Biomaterials 06/2008; 29(15):2415-22. · 7.40 Impact Factor
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ABSTRACT: An innate immune response is often found at the site of biomaterial implantation. Since the effective use of biomaterials in vivo requires good biocompatibility and biofunctionality, it is vital that we assess and compare the inflammatory reactions provoked by various implanted biomaterials in vivo. In the present study, we assessed the host tissue response to poly(lactic-co-glycolic acid) (PLGA)- and small intestinal submucosa (SIS)-based scaffolds subcutaneously implanted in Fischer rats. Our results revealed that the PLGA-based scaffolds resulted in severe post-implantation inflammation, whereas the SIS-based scaffolds induced only a slight post-implantation inflammation and a PLGA/SIS-based copolymer yielded intermediate results.
Biomaterials 01/2008; 28(34):5137-43. · 7.40 Impact Factor
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ABSTRACT: Native small intestinal submucosa (SIS) sheet was prepared by removal of inside and outside layer of porcine jejunum. The acid treated SIS sheet was also prepared by dipping of native SIS sheet in acetic acid solution. The native or acid treated SIS sheets exhibited elastic and soft property on touch. The surface of native SIS sheet appears to be covered with thin and long collagen fibers entangled into networks. The fibers and fibrils at acid treated SIS sheet disappeared due to the acidic erosion of collagen fiber. The water uptake of acid treated SIS sheet (1300%) was higher than that of the native SIS sheet (500%). The cell morphology and proliferation of human bone marrow stem cells (hBMSCs) on SIS sheet was examined. The hBMSCs on the SIS sheet showed a flattened morphology, while cells in the polyglycolic acid (PGA) mesh showed rounded cell morphology. The cell viability on native or acid treated SIS sheet was higher than that of PGA mesh. The hBMSCs in both native and acid treated SIS sheet were grown at a similar rate. The number of adhering hBMSCs increased with incubation time. Thus, we could confirm that native or acid treated SIS sheet could act as a potential scaffold to enhance the hBMSCs proliferation by providing probably natural environments.
International Journal of Biological Macromolecules 01/2008; 41(5):590-6. · 2.45 Impact Factor
