RESUMO
Hypoxia preconditioning enhances the paracrine abilities of mesenchymal stem cells (MSCs) for vascular regeneration and tissue healing. Implantation of hypoxia-induced mesenchymal stem cells (hi-MSCs) may further improve limb perfusion in a murine model of hindlimb ischemia. This study is aimed at determining whether implantation of hi-MSCs is an effective modality for improving outcomes of treatment of ischemic artery diseases. We evaluated the effects of human bone marrow-derived MSC implantation on limb blood flow in an ischemic hindlimb model. hi-MSCs were prepared by cell culture under 1% oxygen for 24 hours prior to implantation. A total of 1 × 105 MSCs and hi-MSCs and phosphate-buffered saline (PBS) were intramuscularly implanted into ischemic muscles at 36 hours after surgery. Restoration of blood flow and muscle perfusion was evaluated by laser Doppler perfusion imaging. Blood perfusion recovery, enhanced vessel densities, and improvement of function of the ischemia limb were significantly greater in the hi-MSC group than in the MSC or PBS group. Immunochemistry revealed that hi-MSCs had higher expression levels of hypoxia-inducible factor-1 alpha and vascular endothelial growth factor A than those in MSCs. In addition, an endothelial cell-inducing medium showed high expression levels of vascular endothelial growth factor, platelet endothelial cell adhesion molecule-1, and von Willebrand factor in hi-MSCs compared to those in MSCs. These findings suggest that pretreatment of MSCs with a hypoxia condition and implantation of hi-MSCs advances neovascularization capability with enhanced therapeutic angiogenic effects in a murine hindlimb ischemia model.
RESUMO
Short tandem repeat (STR) analysis is used in chimerism monitoring after allogeneic hematopoietic stem cell transplantation (HSCT) for patients with various hematologic malignancies. Commercial forensic STR kits often contain loci with huge differences in power of discrimination (PD) across populations, causing some loci to be less informative for chimerism analysis in certain populations. This study aimed to construct a new STR multiplex panel with highly informative loci for efficient chimerism analysis. Thirteen STR markers which exhibit high PD (> 0.9) in at least 80% of 50 populations globally were selected to form a new panel and used in STR analysis of 253 Malaysian subjects. Cumulative power of discrimination (CPD) and combined power of exclusion (CPE) were determined from 253 Malaysian individuals. Loci informativity was assessed and compared to the commercial AmpFLSTR Identifiler PCR Amplification kit in 14 donor-recipient pairs. The new panel had detected 202 unique alleles including five novel alleles from the 253 individuals with high CPD and CPE (> 0.99999999999999999 and > 0.999999997 respectively). All loci from the new panel in the donor-recipient pair analysis showed higher than 50% informativity, while five loci from the commercial kit demonstrated lower than 50% informativity. Four loci from the new panel ranked the highest informativity. A sequenced allelic ladder which consists of 202 unique alleles from the 253 subjects was also developed to ensure accurate allele designation. The new 13-loci STR panel, thus, could serve as an additional powerful, accurate, and highly informative panel for chimerism analysis for HSCT patients.
