Mesenchymal Stem/Stromal Cells in Skeletal Muscle Are Pro-Angiogenic, and the Effect Is Potentiated by Erythropoietin.

The aim of this study was to investigate the angiogenic potential of skeletal muscle mesenchymal stem/stromal cells (mMSCs). Platelet-derived growth factor receptor (PDGFR)-α positive mMSCs secreted vascular endothelial growth factor (VEGF) and hepatocyte growth factor when cultured in an ELISA assay. The mMSC-medium significantly induced endothelial tube formation in an in vitro angiogenesis assay. The mMSC implantation promoted capillary growth in rat limb ischemia models. Upon identifying the erythropoietin receptor (Epo-R) in the mMSCs, we examined how Epo affected the cells. Epo stimulation enhanced the phosphorylation of Akt and STAT3 in the mMSCs and significantly promoted cellular proliferation. Next, Epo was directly administered into the rats' ischemic hindlimb muscles. PDGFR-α positive mMSCs in the interstitial area of muscles expressed VEGF and proliferating cell markers. The proliferating cell index was significantly higher in the ischemic limbs of Epo-treated rats than in untreated controls. Investigations by laser Doppler perfusion imaging and immunohistochemistry demonstrated significantly improved perfusion recovery and capillary growth in the Epo-treated groups versus the control groups. Taken together, the results of this study demonstrated that mMSCs possessed a pro-angiogenic property, were activated by Epo, and potentially contributed to capillary growth in skeletal muscle after ischemic injury.

Synthesis of Soluble Dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) Derivatives: One-Step Functionalization of 2-Bromo-DNTT.

For developing dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) derivatives as solution processable organic semiconductors, we synthesized 2-brominated DNTT (Br-DNTT) as a common precursor to 2-substituted DNTT derivatives. The synthesis of Br-DNTT features chemoselective metalation and cross-coupling reactions that enable us to keep the 2-bromo group intact from the starting material, 2-bromo-6-methoxynaphthalene, to Br-DNTT. We demonstrated one-step functionalization of Br-DNTT by various palladium- and copper-catalyzed cross-coupling reactions to introduce a variety of substituents, including ethynyl, aryl, heteroaryl, alkyl, alkoxy, and alkylthio groups, in yields of 73 to 98%. The resulting 12 examples of 2-substituted DNTT derivatives, which have bulky or flexible solubilizing groups, have improved solubilities of up to 200 times the solubility of unsubstituted DNTT. Some of the soluble 2-substituted DNTT derivatives were applied to the solution-processed fabrication of organic field-effect transistor (OFET) devices. Most of the OFET devices exhibited average hole mobilities in the order of 10-1 to 10-2 cm2 V-1 s-1. Among the DNTT derivatives, the one substituted with 4-(2-(2-methoxyethoxy)ethoxy)butyl group has the highest solubility of 8.45 g L-1 and also exhibited the highest average hole mobility of 0.28 cm2 V-1 s-1 in the OFET devices.

Bone marrow-derived mesenchymal stem cells inhibit vascular smooth muscle cell proliferation and neointimal hyperplasia after arterial injury in rats.

We investigated whether mesenchymal stem cell (MSC)-based treatment could inhibit neointimal hyperplasia in a rat model of carotid arterial injury and explored potential mechanisms underlying the positive effects of MSC therapy on vascular remodeling/repair. Sprague-Dawley rats underwent balloon injury to their right carotid arteries. After 2 days, we administered cultured MSCs from bone marrow of GFP-transgenic rats (0.8 × 106 cells, n = 10) or vehicle (controls, n = 10) to adventitial sites of the injured arteries. As an additional control, some rats received a higher dose of MSCs by systemic infusion (3 × 106 cells, tail vein; n = 4). Local vascular MSC administration significantly prevented neointimal hyperplasia (intima/media ratio) and reduced the percentage of Ki67 + proliferating cells in arterial walls by 14 days after treatment, despite little evidence of long-term MSC engraftment. Notably, systemic MSC infusion did not alter neointimal formation. By immunohistochemistry, compared with neointimal cells of controls, cells in MSC-treated arteries expressed reduced levels of embryonic myosin heavy chain and RM-4, an inflammatory cell marker. In the presence of platelet-derived growth factor (PDGF-BB), conditioned medium from MSCs increased p27 protein levels and significantly attenuated VSMC proliferation in culture. Furthermore, MSC-conditioned medium suppressed the expression of inflammatory cytokines and RM-4 in PDGF-BB-treated VSMCs. Thus, perivascular administration of MSCs may improve restenosis after vascular injury through paracrine effects that modulate VSMC inflammatory phenotype.

Kisspeptin-10 induces endothelial cellular senescence and impaired endothelial cell growth.

The KPs (kisspeptins) are a family of multifunctional peptides with established roles in cancer metastasis, puberty and vasoconstriction. The effects of KPs on endothelial cells have yet to be determined. The aim of the present study was to investigate the effects of KP-10 on endothelial cell growth and the mechanisms underlying those effects. The administration of recombinant KP-10 into the hindlimbs of rats with ischaemia significantly impaired blood flow recovery, as shown by laser Doppler, and capillary growth, as shown using histology, compared with the controls. HUVECs (human umbilical vein endothelial cells) express the KP receptor and were treated with KP-10 in culture studies. KP-10 inhibited endothelial cell tube formation and proliferation in a significant and dose-dependent manner. The HUVECs treated with KP exhibited the senescent phenotype, as determined using a senescence-associated ß-galactosidase assay, cell morphology analysis, and decreased Sirt1 (sirtuin 1) expression and increased p53 expression shown by Western blot analysis. Intriguingly, a pharmacological Rho kinase inhibitor, Y-27632, was found to increase the proliferation of HUVECs and to reduce the number of senescent phenotype cells affected by KP-10. In conclusion, KP-10 suppressed endothelial cells growth both in vivo and in vitro in the present study. The adverse effect of KP on endothelial cells was attributable, at least in part, to the induction of cellular senescence.