Rui-Peng Jia

Experimental Study on Early Protective Effect of Ischemic Preconditioning on Rat Kidney Graft

OBJECTIVE Our aim was to investigate the mechanisms of early protection by ischemic preconditioning (IPC) of transplanted rat kidneys. MATERIALS AND METHODS Thirty-six male donor and recipient Sprague-Dawley (SD) rats were randomly divided into 3 groups: sham-operated (A), transplantation (B), and IPC treatment (C) groups. Group A underwent exploratory laparotomy, group B received orthotopic transplantation, and group C, 15 minutes of ischemia followed by 10 minutes of reperfusion before transplantation. We measured the serum creatinine (SCr), blood urea nitrogen (BUN), and degree of kidney graft ischemic/reperfusion injury (IRI) by tumor necrosis factor-alpha (TNF-alpha) IkappaB kinase beta (IKK-beta) nuclear factor-kappa beta (NF-kappabeta) p65 subunit mRNA expressions. RESULTS The SCr and BUN levels in groups C and B were higher than those in the sham-operated group (P < .01), without a significant difference between groups C and B at 24 hours after transplantation (P > .05). The degree of renal graft tubular injury in group C was significantly lower than that in group B (P < .01). TNF-alpha transcription levels at 24 hours after transplantation were significantly lower compared with the non-IPC group (P < .01). However, we failed to note a significant difference in IKK-beta or p65 mRNA expressions between groups C and B (P > .05). CONCLUSIONS One cycle of preconditioning (15 min/10 min) attenuated renal graft IRI in the early phase. The inhibiting effects on TNF-alpha and the positive feedback signaling of TNF-alpha/NF-KB pathways may play important roles in renal graft protection.

In Vitro Evaluation of Endothelial Progenitor Cells from Adipose Tissue as Potential Angiogenic Cell Sources for Bladder Angiogenesis

Autologous endothelial progenitor cells (EPCs) might be alternative angiogenic cell sources for vascularization of tissue-engineered bladder, while isolation and culture of EPCs from peripheral blood in adult are usually time-consuming and highly inefficient. Recent evidence has shown that EPCs also exist in the adipose tissue. As adipose tissue is plentiful in the human body and can be easily harvested through a minimally invasive method, the aim of this study was to culture and characterize EPCs from adipose tissue (ADEPCs) and investigate their potential for the neovascularization of tissue-engineered bladder. Adipose stromal vascular fraction (SVF) was isolated and used for the culture of ADEPCs and adipose derived stem cells (ADSCs). After SVF was cultured for one week, ADEPCs with typical cobblestone morphology emerged and could be isolated from ADSCs according to their different responses to trypsinization. Rat bladder smooth muscle cells (RBSMCs) were isolated and cultured from rat bladder. RBSMCs exhibited typical spindle-shaped morphology. ADEPCs had higher proliferative potential than ADSCs and RBSMCs. ADEPCs stained positive for CD34, Stro-1, VEGFR-2, eNOS and CD31 but negative for α-SMA, CD14 and CD45. ADSCs stained positive for CD34, Stro-1 and α-SMA but negative for VEGFR-2, eNOS, CD31, CD14 and CD45. RBSMCs stained only positive for α-SMA. ADEPCs could be expanded from a single cell at an early passage to a cell cluster containing more than 10,000 cells. ADEPCs were able to uptake DiI-Ac-LDL, bind UEA-1 and form capillary-like structures in three-dimensional scaffolds (Matrigel and bladder acellular matrix). ADEPCs were also able to enhance the human umbilical vein endothelial cells’ capability of capillary-like tube formation on Matrigel. Additionally, significantly higher levels of mRNA and protein of vascular endothelial growth factor were found in ADEPCs than in RBSMCs. These results suggest the potential use of ADEPCs as angiogenic cell sources for engineering bladder tissue.

Effects of ischemic preconditioning in the late phase on homing of endothelial progenitor cells in renal ischemia/reperfusion injury.

OBJECTIVE The aim of this study was to determine whether the mobilization and recruitment of endothelial progenitor cells (EPCs) contribute to the protection of kidneys from ischemia/reperfusion (I/R) injury after ischemic preconditioning (IPC) during the late phase. METHODS Seventy-five male Sprague-Dawley rats were divided into the following groups: sham-operated (group A; n = 25), ischemia/reperfusion hosts that underwent 45 minutes of left renal artery ischemia (group B; n = 25), and ischemic preconditioning-treated group (group C; n = 25). Group C underwent 3 cycles of 5 minutes of occlusion and 5 minutes of reperfusion followed by 24 hours of reperfusion before the following 45 minutes of occlusion. Serum samples were collected and renal tissues harvested for histological examination terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, immunohistochemical staining, and Western blot analysis to determine the expression levels of CD34, VEGFR-2 (Vascular Endothelial Growth Factor Receptor 2)/flk-1, vascular endothelial growth factor (VEGF), and stromal cell-derived factor-1α (SDF-1α). RESULTS Compared with group B, the levels of blood urea nitrogen (BUN), serum creatinine (Scr) and acute tubulointerstitial injury at 24 hours after operation were significantly reduced in group C. At 72 hours, tubular epithelial cell apoptosis was also decreased (17.6 ± 4.45 vs 63.8 ± 6.10; P < .01). CD34+ and flk-1+ cells that mostly accumulated in the medullopapillary parenchyma were significantly increased at 72 hours (P < .05). Expression levels of VEGF and SDF-1α were also significantly higher in group C (P < .05). CONCLUSION The present work suggested that IPC protected kidneys from IR injury in the later phase through enhanced mobilization and recruitment of EPCs. VEGF and SDF-1α may play important roles in this protective effect.

The Renoprotective Effect of Bone Marrow-Derived Endothelial Progenitor Cell Transplantation on Acute Ischemia-Reperfusion Injury in Rats

OBJECTIVE To investigate the renoprotective effects of exogenous endothelial progenitor cells (EPCs) on acute renal ischemia-reperfusion (I/R) injury in rats. METHODS EPCs were collected by in vitro culture of mononuclear cells derived from rat bone marrow. The EPC labeling was performed using chloromethyl-benzamidodialkylcarbocyanine (CM-Dil). Sprague-Dawley rats were equally randomized into an I/R, an EPC, and a control group. We evaluated blood urea nitrogen (BUN) and serum creatinine (Scr), kidney morphology, apoptosis and microvessel density. EPC homing into I/R injured kidneys was observed using a fluorescence microscope. RESULTS After EPC transplantation, CM-Dil-labeled EPCs were noted at the corticomedullary junction of injured kidneys. The levels of BUN and Scr were markedly lower among the EPC than the I/R group (P < .05). The histopathologic score was higher in the I/R than the EPC group (P < .05). Apoptosis of tubular epithelial cells was substantially reduced among EPC-treated rats (P < .01). In addition, more CD34(+) microvessels were documented among the EPC than the other two groups (P < .01). The expression levels of vascular endothelial growth factor (VEGF) were also increased greatly in the EPC group (P < .05). CONCLUSION Transplanted exogenous EPCs exert protective effects on renal function by maintaining the integrity of peritubular capillaries after I/R injury.

Ischemic Preconditioning Increases Endothelial Progenitor Cell Number to Attenuate Partial Nephrectomy-Induced Ischemia/Reperfusion Injury

Objectives The objective of this study was to investigate the role of endothelial progenitor cells (EPCs) in the modulation of ischemia-reperfusion injury (IRI) in a partial nephrectomy (PN) rat model using early-phase ischemic preconditioning (IPC). Materials and Methods Ninety male Sprague-Dawley rats were randomly divided into three groups following right-side nephrectomy: Sham-operated rats (surgery without vascular clamping); PN rats (renal blood vessels were clamped for 40 min and PN was performed); and IPC rats (pretreated with 15 min ischemia and 10 min reperfusion). At 1, 3, 6, 12, 24 h, and 3 days after reperfusion, the pool of circulating EPCs and kidneys were harvested. The extent of renal injury was assessed, along with EPC number, cell proliferation, angiogenesis, and vascular growth factor expression. Results Pretreated rats exhibited significant improvements in renal function and morphology. EPC numbers in the kidneys were increased at 12 h following reperfusion in the IPC group as compared to the PN or Sham groups. Cell proliferation (including endothelial and tubular epithelial cells) and angiogenesis in peritubular capillaries were markedly increased in kidneys treated with IPC. In addition, vascular endothelial growth factor-A (VEGF-A) and stromal cell-derived factor-1α (SDF-1α) expression in the kidneys of pretreated rats was increased compared to rats subjected to PN. Conclusions Our investigation suggested that: (1) the early phase of IPC may attenuate renal IRI induced by PN; (2) EPCs play an important role in renal protection, involving promotion of cell proliferation and angiogenesis through release of several angiogenic factors.

Renal cell carcinoma-adjacent tissues enhance mobilization and recruitment of endothelial progenitor cells to promote the invasion of the neoplasm.

AIMS The aim of this study was to detect the levels of CD34(+)/Flk-1(+) endothelial progenitor cells (EPCs) in renal cell carcinoma (RCC)-adjacent tissues and explore the correlation of RCC-adjacent tissues EPCs and tumor invasion. METHODS An orthotopic renal tumor model was successfully established. At days 7, 12, 17 and 21, eight mice were put to death respectively. Tumor diameters were measured and RCC-adjacent tissues were collected. The percentage of EPCs within the kidney mononuclear cell population was detected. The expression levels of Stromal cell-derived factor-1 (SDF-1), vascular endothelial growth factor (VEGF) and their receptors CXCR4, Flk-1 mRNA and protein were probed respectively. And then, mean microvascular density (MVD) was examined. RESULTS EPC numbers in RCC-adjacent tissues were significantly higher than those in control groups. The ratios of EPCs were increased gradually, and so were tumor diameters. The levels of SDF-1 and VEGF were also increased gradually, but significantly reduced compared with control group at each time point. In addition, CXCR4 and Flk-1 expression were decreased gradually. CONCLUSIONS Our investigation suggested that EPCs in RCC-adjacent tissues play an important role in early stage RCC invasion, involving the promotion on angiogenesis through releasing several angiogenic factors.

Combined Effects of TGFB1 +869 T/C and +915 G/C Polymorphisms on Acute Rejection Risk in Solid Organ Transplant Recipients: A Systematic Review and Meta-Analysis

Background Transforming growth factor-beta 1(TGF-β1) is involved in the development of acute rejection (AR) episodes in solid organ transplant recipients; and a number of studies have been conducted to investigate the combined effects of human TGF-β1 gene (TGFB1) +869 T/C and +915 G/C polymorphisms on AR risk. However, the results obtained are inconclusive. Methods Eligible studies that investigated the haplotypic association between TGFB1 +869 T/C and +915 G/C polymorphisms and AR risk were comprehensively searched in the PUBMED, EMBASE, China National Knowledge Infrastructure, and Wanfang Database. Statistical analyses were performed by using STATA 12.0 and Review Manager 5.0. Results Fourteen eligible studies with 565 AR cases and 1219 non-AR cases were included. Overall, a significantly decreased risk was detected in patients carried with intermediate producer (IP) haplotypes (T/C G/C, T/T G/C, and C/C G/G) and/or low producer (LP) haplotypes (C/C G/C, C/C C/C, T/T C/C, and T/C C/C) compared with high producer (HP) haplotypes (T/T G/G and T/C G/G; IP vs. HP: OR = 0.75, 95% CI, 0.58–0.96, P heterogeneity  = 0.238; IP/LP vs. HP: OR  = 0.77, 95% CI, 0.61–0.98, P heterogeneity  = 0.144). In addition, subgroup analysis by transplant types demonstrated a similar association in patients receiving heart transplant (IP vs. HP: OR  = 0.32, 95% CI, 0.14–0.73, P heterogeneity  = 0.790; IP/LP vs. HP: OR  = 0.41, 95% CI, 0.20–0.85, P heterogeneity  = 0.320). Conclusions The current meta-analysis and systematic review indicated that recipient TGFB1 HP haplotypes were significantly associated with an increased risk for AR in solid organ transplant recipients, particularly patients receiving cardiac allograft.

Association between transforming growth factor beta-1 + 869 T/C polymorphism and acute rejection of solid organ allograft: A meta-analysis and systematic review

BACKGROUND Transforming growth factor beta-1(TGFB1) is involved in the acute rejection (AR) episodes of solid organ transplant recipients. However, results from published studies on the association between donor/recipient TGFB1 +869T/C polymorphism and AR risk are conflicting and inconclusive. METHODS PUBMED, EMBASE, CNKI and Wanfang Database were searched to identify eligible studies investigating the association between donor/recipient TGFB1 +869T/C polymorphism and AR risk. Statistical analysis was performed by using STATA 10.0. RESULTS A total of 29 studies were included. Overall, the donor TGFB1 +869T/C polymorphism was significantly associated with AR risk in heterozygote comparison (CT vs. TT: OR = 1.67, 95%CI, 1.17-2.39; P heterogeneity=0.285) and dominant model (CC vs. TC/TT OR = 1.47, 95%CI, 1.05-2.06; P heterogeneity=0.445). In addition, subgroup analysis revealed that CT variant (CT vs. TT: OR = 1.97, 95%CI, 1.20-3.25; P heterogeneity = 0.777) and CC/CT genotype (CC/CT vs. TT: OR = 1.72, 95%CI, 1.07, 2.78; P heterogeneity = 0.619) within donors contributed to higher risk of AR in recipients administrated with CsA or FK506, compared with those applied only CsA. On the other hand, no significant association between recipient TGFB1 +869T/C polymorphism and AR was detected in all genetic models. CONCLUSIONS This meta-analysis and systematic review suggested that donor TGFB1 +869T/C polymorphism was significantly associated with AR of solid organ transplant recipients, and especially among patients in CsA/FK 506 group compared with those in CsA group.

Limited Clinical Utility of Remote Ischemic Conditioning in Renal Transplantation: A Meta-Analysis of Randomized Controlled Trials

[This corrects the article DOI: 10.1371/journal.pone.0170729.].

AB110. In vitro evaluation of endothelial progenitor cells from adipose tissue as potential angiogenic cell sources for bladder angiogenesis

Objective Autologous endothelial progenitor cells (EPCs) might be alternative angiogenic cell sources for vascularization of tissue-engineered bladder, while isolation and culture of EPCs from peripheral blood in adult are usually time-consuming and highly inefficient. Recent evidence has shown that EPCs also exist in the adipose tissue. As adipose tissue is plentiful in the human body and can be easily harvested through a minimally invasive method, the aim of this study was to culture and characterize endothelial progenitor cells from adipose tissue (ADEPCs) and investigate their potential for the neovascularization of tissue-engineered bladder. Methods Adipose stromal vascular fraction (SVF) was isolated and used for the culture of ADEPCs and adipose derived stem cells (ADSCs). Rat bladder smooth muscle cells (RBSMCs) were isolated and cultured from rat bladder. Cells were characterized by immunofluorescence staining and flow cytometric analysis. The capabilities of cell proliferation, DiI-Ac-LDL uptake, and UEA-1 binding were evaluated. Real-time RT-PCR and ELISA were performed to assess the expression of angiogenic factors. ADEPCs were seeded onto matrigel and bladder acellular matrix (BAM), and the capability of tube formation in these scaffolds was evaluated. Results After SVF was cultured for one week, ADEPCs with typical cobblestone morphology emerged and could be isolated from ADSCs according to their different responses to trypsinization. RBSMCs exhibited typical spindle-shaped morphology. ADEPCs had higher proliferative potential than ADSCs and RBSMCs. ADEPCs stained positive for CD34, Stro-1, VEGFR-2, eNOS and CD31 but negative for α-SMA, CD14 and CD45. ADSCs stained positive for CD34, Stro-1 and α-SMA but negative for VEGFR-2, eNOS, CD31, CD14 and CD45. RBSMCs stained only positive for α-SMA. ADEPCs could be expanded from a single cell at an early passage to a cell cluster containing more than 10,000 cells. ADEPCs were able to uptake DiI-Ac-LDL, bind UEA-1 and form capillary-like structures in three-dimensional scaffolds (matrigel and bladder acellular matrix). ADEPCs were also able to enhance the human umbilical vein endothelial cells’ capability of capillary-like tube formation on matrigel. Additionally, significantly higher levels of mRNA and protein of vascular endothelial growth factor were found in ADEPCs than in RBSMCs. Conclusions These results suggest the potential use of ADEPCs as angiogenic cell sources for engineering bladder tissue.