Search

The microvascular network plays an important role in providing nutrients to the injured tissue and exchanging various metabolites. However, how to achieve efficient penetration of the injured tissue is an important bottleneck restricting the reconstruction of microvascular network. Herein, the hydrogel precursor solution can efficiently penetrate the damaged tissue area, and ultrasound triggers the release of thrombin from liposomes in the solution to hydrolyze fibrinogen, forming a fibrin solid hydrogel network in situ with calcium ions and transglutaminase as catalysts, effectively solving the penetration impedance bottleneck of damaged tissues and ultimately significantly promoting the formation of microvascular networks within tissues. First, the fibrinogen complex solution is effectively permeated into the injured tissue. Second, ultrasound triggered the release of calcium ions and thrombin, activates transglutaminase, and hydrolyzes fibrinogen. Third, fibrin monomers are catalyzed to form fibrin hydrogels in situ in the damaged tissue area. In vitro studies have shown that the fibrinogen complex solution effectively penetrated the artificial bone tissue within 15 s after ultrasonic triggering, and formed a hydrogel after continuous triggering for 30 s. Overall, this innovative strategy effectively solved the problem of penetration resistance of ultrasound‐triggered hydrogels in the injured tissues, and finally activates in situ microvascular networks regeneration. [ABSTRACT FROM AUTHOR]

Background: Microvascular dysfunction is one of the most common pathological characteristics in Type 2 diabetes. Human mesenchymal stem cell-derived exosomes (hUCMSCs-Exo) have diverse functions in improving microcirculation; however, the molecular mechanism of hUCMSCs-Exo in regulating burn-induced inflammation is not well understood. Methods: hUCMSCs-Exo were extracted by hypervelocity centrifugation method, and exosome morphology was observed by transmission electron microscopy, exosome diameter distribution was detected by particle size analysis, and exosome specific proteins were identified by Western blot.2. DB/DB mice were randomly divided into exosomes group and PBS group. Exosomes and PBS were injected into the tail vein, respectively, and the calf muscle tissue was taken 28 days later. 0.5% Evans blue fluorescence assessment microvascular permeability. The expression of CD31 was detected by immunofluorescence.The morphology and function of microvessels in muscle tissue of lower limbs was evaluated by transmission electron microscopy.3. TMT proteomics was used to detect the changes of differential protein expression in lower limb muscle tissues of the PBS group and the exosome group, and data analysis was performed to screen key signal molecules and their involved biological pathways. Key signal molecules CD105 were verified by Western blot. The expression of TGF-β1 in exosomes were evaluated by Western blot. Results: Electron microscopy showed that hUCMSCs-Exo presented a uniform vesicle structure, and NTA showed that its diameter was about 160 nm. Western blot showed positive expression of specific proteins CD9, CD81 and TSG101 on exosomes.2. There is no significant change in blood glucose and body weight before and after the exosome treatment. The exosome group can significantly reduce the exudation of Evans blue. Compared with the PBS group. Meanwhile, CD31 immunofluorescence showed that the red fluorescence of exosome treatment was significantly increased, which was higher than that of PBS group. Transmission electron microscopy showed smooth capillary lumen and smooth and complete surface of endothelial cells in the exosome group, while narrow capillary lumen and fingerlike protrusion of endothelial cells in the PBS group.3.Quantitative analysis of TMT proteomics showed that there were 82 differential proteins, including 49 down-regulated proteins and 33 up-regulated proteins. Go enrichment analysis showed that the differential proteins were involved in molecular function, biological process, cell components,among which CD105 was one of the up-regulated proteins. Through literature search, CD105 was found to be related to endothelial cell proliferation. Therefore, this study verified the changes of CD105 in the exosome group, and it was used as the mechanism study of this study. 4. Western blot analysis showed that the expression of CD105 protein in lower limb muscle tissue of exosome group was significantly increased compared with that of PBS group. Based on the fact that CD105 is a component of the TGF-β1 receptor complex and exosomes are rich in growth factors and cytokines, this study further examined the expression of TGF-β1 in exosomes, and the results showed that exosomes had high expression of TGF-β1. Conclusion: By improving the integrity of microvascular endothelial cells, hUCMSCs-Exo can improve the permeability of microvessels in diabetic lower muscle tissue, further promote the proliferation of lower limb muscle cells and inhibit the apoptosis of tissue cells. The mechanism may be associated with exosomes rich in TGF-β1, which is likely to promote endothelial cell proliferation and improve permeability through binding to the endothelial CD105/TβR-II receptor complex, while promoting angiogenesis and protecting skeletal muscle cells from apoptosis. [ABSTRACT FROM AUTHOR]

Microvascular lesion in diabetic peripheral arterial disease (PAD) still cannot be resolved by current surgical and interventional technique. Endothelial cells have the therapeutic potential to cure microvascular lesion. To evaluate the efficacy and immune-regulatory impact of intra-arterial infusion of autologous CD133+ cells, we recruited 53 patients with diabetic PAD (27 of CD133+ group and 26 of control group). CD133+ cells enriched from patients’ PB-MNCs were reinfused intra-arterially. The ulcer healing followed up till 18 months was 100% (3/3) in CD133+ group and 60% (3/5) in control group. The amputation rate was 0 (0/27) in CD133+ group and 11.54% (3/26) in control group. Compared with the control group, TcPO2 and ABI showed obvious improvement at 18 months and significant increasing VEGF and decreasing IL-6 level in the CD133+ group within 4 weeks. A reducing trend of proangiogenesis and anti-inflammatory regulation function at 4 weeks after the cells infusion was also found. These results indicated that autologous CD133+ cell treatment can effectively improve the perfusion of morbid limb and exert proangiogenesis and anti-inflammatory immune-regulatory impacts by paracrine on tissue microenvironment. The CD133+ progenitor cell therapy may be repeated at a fixed interval according to cell life span and immune-regulatory function. [ABSTRACT FROM AUTHOR]

Microvascular lesion in diabetic peripheral arterial disease (PAD) still cannot be resolved by current surgical and interventional technique. Endothelial cells have the therapeutic potential to cure microvascular lesion. To evaluate the efficacy and immune-regulatory impact of intra-arterial infusion of autologous CD133+ cells, we recruited 53 patients with diabetic PAD (27 of CD133+ group and 26 of control group). CD133+ cells enriched from patients’ PB-MNCs were reinfused intra-arterially. The ulcer healing followed up till 18 months was 100% (3/3) in CD133+ group and 60% (3/5) in control group. The amputation rate was 0 (0/27) in CD133+ group and 11.54% (3/26) in control group. Compared with the control group, TcPO2 and ABI showed obvious improvement at 18 months and significant increasing VEGF and decreasing IL-6 level in the CD133+ group within 4 weeks. A reducing trend of proangiogenesis and anti-inflammatory regulation function at 4 weeks after the cells infusion was also found. These results indicated that autologous CD133+ cell treatment can effectively improve the perfusion of morbid limb and exert proangiogenesis and anti-inflammatory immune-regulatory impacts by paracrine on tissue microenvironment. The CD133+ progenitor cell therapy may be repeated at a fixed interval according to cell life span and immune-regulatory function. [ABSTRACT FROM AUTHOR]

Background/Aims: Atherosclerosis is associated with dysfunction of endothelial progenitor cells (EPCs). Tripterine, a chemical compound derived from the Chinese medicinal plant Tripterygium wilfordii Hook, displays anti-inflammatory properties in several animal models. We hypothesized that tripterine can improve EPC function and thus the efficiency of EPC transplantation. Methods and Results: Tripterine preconditioning (2.5 μM, 4 h) improved EPC proliferation, tube formation, migration, and adhesion, and reduced apoptosis in cells cultured in ox-LDL (200 ug/ml). Tripterine restored integrin-linked kinase (ILK) levels downregulated by ox-LDL in EPCs, suggesting the involvement of the ILK/Akt pathway. Small interfering RNA-mediated depletion of ILK and dominant-negative ILK transduction inhibited the phosphorylation of the ILK downstream signaling targets protein kinase B/ Akt and glycogen synthase kinase 3-beta (GSK-3β), and reduced β-catenin and cyclin D1 expression. In atherosclerotic mice injected with green fluorescent protein-labeled EPCs to evaluate EPC function, tripterine decreased aortic lesions and plaque deposition, and injection of tripterine-treated EPCs restored ILK levels. Conclusion: The present results suggest that tripterine improves vascular function in atherosclerosis by enhancing EPC function through a mechanism involving the ILK signaling pathway. [ABSTRACT FROM AUTHOR]

The dysfunction of endothelial progenitor cells (EPCs) limits their potential for the treatment of ischemia and atherosclerosis. Therefore, we investigated the effect of tripterine on EPC function and examined the underlying mechanisms. The effect of tripterine, an active component of Tripterygium wilfordii Hook, on the enhancement of EPC function and the efficiency of EPC transplantation was investigated in vitro and in vivo. Treatment of EPCs with tripterine at 2.5 µM for 4 h inhibited oxidized low-density lipoprotein (ox-LDL) induced ROS production, cell apoptosis, and cell senescence and improved the migration and tube formation capacities of EPCs treated with ox-LDL (200 µg/ml). In vivo studies showed that tripterine conditioning of EPCs administered to ischemic foci improved blood perfusion and microvascular density in a mouse hindlimb ischemia model. Examination of the underlying mechanisms indicated that the effect of tripterine is mediated by the induction of heat shock protein 32 expression and the inhibition of JNK activation. The present results are of clinical significance because they suggest the potential of tripterine as a therapeutic agent to improve the efficacy of EPC transplantation for the treatment of ischemic diseases. J. Cell. Physiol. 230: 1139-1147, 2015. © 2014 Wiley Periodicals, Inc., A Wiley Company [ABSTRACT FROM AUTHOR]

Background: Dysfunction of circulating endothelial progenitor cells (EPCs) is associated with the onset of cardiovascular disorders. Circulating microRNAs (miRNAs) have been recognized as novel biomarkers and potential therapeutic targets. Here, we examined the role of miR-26a overexpression in atherosclerosis and explored the underlying mechanisms. Methods: EPCs were obtained from patients with atherosclerosis and healthy controls. Bone marrow (BM)-derived EPCs were exposed to hypoxia to mimic the atherosclerotic environment and miR-26a, EphA2 and p38 MAPK levels were measured by qRT-PCR and western blotting, and VEGF levels were determined by enzyme linked immunosorbent assay. Cell viability was assessed using the MTT assay, and luciferase activity assays confirmed EphA2 as a target of miR-26a. Results: MiR-26a was overexpressed in patients with atherosclerosis and associated with EPC dysfunction. EphA2 was identified as a direct target of miR-26a. Overexpression of miR-26a downregulated EphA2 and impaired EPC function, whereas knockdown of miR-26a upregulated EphA2 and reversed hypoxia-induced EPC dysfunction. MiR-26a overexpression or knockdown modulated the activity of p38 MAPK and the levels of VEGF in EPCs. Conclusions: The role of miR-26a in atherosclerosis is mediated by its target EphA2 via a mechanism involving the p38 MAPK/VEGF pathway. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Small GTPases (guanosine triphosphate, GTP) are involved in many critical cellular processes, including inflammation, proliferation, and migration. GTP loading and isoprenylation are two important post-translational modifications of small GTPases, and are critical for their normal function. In this study, we investigated the role of post-translational modifications of small GTPases in regulating endothelial cell inflammatory responses and junctional integrity. Methods and Results: Confluent human umbilical vein endothelial cell (HUVECs ) treated with atorvastatin demonstrated significantly decreased lipopolysaccharide (LPS)-mediated IL-6 and IL-8 generation. The inhibitory effect of atorvastatin (Atorva) was attenuated by co-treatment with 100 µM mevalonate (MVA) or 10 µM geranylgeranyl pyrophosphate (GGPP), but not by 10 µM farnesyl pyrophosphate (FPP). Atorvastatin treatment of HUVECs produced a time-dependent increase in GTP loading of all Rho GTPases, and induced the translocation of small Rho GTPases from the cellular membrane to the cytosol, which was reversed by 100 µM MVA and 10 µM GGPP, but not by 10 µM FPP. Atorvastatin significantly attenuated thrombin-induced HUVECs permeability, increased VE-cadherin targeting to cell junctions, and preserved junction integrity. These effects were partially reversed by GGPP but not by FPP, indicating that geranylgeranylation of small GTPases plays a major role in regulating endothelial junction integrity. Silencing of small GTPases showed that Rho and Rac, but not Cdc42, play central role in HUVECs junction integrity. Conclusions: In conclusion, our studies show that post-translational modification of small GTPases plays a vital role in regulating endothelial inflammatory response and endothelial junction integrity. Atorvastatin increased GTP loading and inhibited isoprenylation of small GTPases, accompanied by reduced inflammatory response and preserved cellular junction integrity. [ABSTRACT FROM AUTHOR]