Study of clinical practical model of urinary system injury.

BACKGROUND: In order to improve the clinical treatment level of urinary system injury, it is necessary to build up an animal model of urinary system wound, which is not only analogous to real clinical practice, but also simple and practical. METHODS: We have developed the third generation of firearm fragment wound generator based on the first and the second producer. The best explosive charge of the blank cartridge was selected by gradient powder loading experiments. The firearm fragment injuries were made to the bulbous urethra of 10 New Zealand male rabbits. One week preoperatively and 2, 4 and 8 weeks postoperatively, all the animals underwent urethroscopy and urethrography. At 2, 4 and 8 weeks postoperatively, two animals were randomly selected and killed, and the urethra was cut off for pathological examination. RESULTS: The shooting distance of the third generation of firearm fragment wound generator is 2 cm. The best explosive charge of the blank cartridge is 1 g of nitrocotton. All rabbits survived the procedures and stayed alive until they were killed. Injuries were limited to bulbous urethra and distal urethra. Round damaged areas, 1-1.5 cm in length, on the ventral wall were observed. Ureteroscopy results showed that canal diameter gradually shrank by over 50% in 9 rabbits. The rate of success was 90%. Urethrography result noted that a 1-1.3 cm stricture was formed at the bulbous urethra. Histology results of injured stricture urethra showed that fibrous connective tissue hyperplasia and hyaline degeneration caused further stricture in the canal. CONCLUSIONS: The third generation of firearm fragment wound generator imitates the bullet firing process and is more accurate and repeatable. The corresponding rabbit model of traumatic complex urethral stricture simulates the real complex clinical conditions. This animal model provides a standardized platform for clinical researches on treating traumatic injuries to the urinary system.

Clinical efficacy of rituximab for acute rejection in kidney transplantation: a meta-analysis.

OBJECTIVES: This meta-analysis was undertaken to compare the efficacy and safety of pretransplant treatment with rituximab in sensitized patients receiving kidney transplantation. METHODS: PubMed, EMBASE, and Cochrane databases were searched to identify studies that used pretransplantation rituximab in eligible patients. The major outcomes included antibody-mediated rejections (AMR) after kidney transplantation and one-year graft survival rate. The meta-analysis was performed using fixed-effects model. RESULTS: Seven studies were identified including a total of 589 patients, of whom 312 were treated without rituximab, while 277 were treated with rituximab. In our meta-analysis, patients treated with rituximab had significantly fewer AMR after kidney transplantation [odds ratio (OR) 0.52, 95 % CI 0.28, 0.98, P = 0.04] and higher rate of one-year graft survival rates (OR 3.02, 95 % CI 1.14, 8.02, P = 0.03), indicating that rituximab is effective against acute rejection and enhances graft survival in kidney transplantation. No differences were noted in other efficacy and safety parameters in these two patient groups. CONCLUSIONS: We demonstrated that preinduction with rituximab could significantly improve AMR and graft survival rates in sensitized patients undergoing kidney transplantation. Future prospective controlled studies are warranted to further understand rituximab's role in kidney transplantation.

Dynamic expression changes between non-muscle-invasive bladder cancer and muscle-invasive bladder cancer.

AIMS AND BACKGROUND: Despite elaborate characterization of the risk factors, bladder cancer is still a major epidemiological problem whose incidence continues to rise each year. We aim to investigate the dynamic expression changes between non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). METHODS: The gene expression profile GSE13507 was obtained from the Gene Expression Omnibus, and the R package was used to identify gene expression signatures (GESs) between NMIBC and MIBC. Gene ontology enrichment analysis was performed for GES function analysis. We used miRTarBase and TargetScan to identify the differentially regulated microRNAs, and TfactS to identify transcription factors between NMIBC and MIBC. Bionet was used to identify the differentially expressed subnetwork. RESULTS: A total of 802 upregulated NMIBC GESs and 668 downregulated MIBC GESs were identified. Functional enrichment analysis revealed that the MIBC GESs were majorly involved in cell cycle and inflammatory response. miR-29c and miR-9 were regarded as key microRNAs in MIBC. SMAD3 in MIBC and SMAD5 and SMAD7 in NMIBC were potential activated transcription factors. In addition, a subnetwork that was considered to capture the differences between MIBC and NMIBC was identified, of which GRB2 and UBC were the hub nodes. CONCLUSIONS: Some key microRNAs, activated transcription factors and hub nodes have been identified in this study, which may be used as potential biomarkers or targets for the diagnosis, treatment and detection of bladder cancer at different stages.

The association between fish consumption and risk of renal cancer: a meta-analysis of observational studies.

BACKGROUND: Several case-control studies and cohort studies have investigated the association between fish intake and renal cancer risk, however, they yielded conflicting results. To our knowledge, a comprehensive assessment of the association between fish consumption and risk of renal cancer has not been reported. Hence, we conducted a systematic literature search and meta-analysis to quantify the association between fish consumption and renal cancer. METHODS: A systematic search was performed using the PubMed, Embase, and Cochrane Library Central database for case-control and cohort studies that assessed fish intake and risk of renal cancer. Two authors independently assessed eligibility and extracted data. Fixed-effect and random-effect models were used to estimate summary relative risks (RR) and the corresponding 95% confidence intervals (CIs). Subgroup analyses, sensitivity analysis and cumulative meta-analysis were also performed. RESULTS: A total of 12 case-control studies and three cohort studies published between 1990 and 2011 were included in the meta-analysis, involving 9,324 renal cancer cases and 608,753 participants. Meta-analysis showed that fish consumption did not significantly affect the risk of renal cancer (RR=0.99, 95% CI [0.92,1.07]). In our subgroup analyses, the results were not substantially affected by study design, region, gender, and confounder adjustments. Furthermore, sensitivity analysis confirmed the stability of results. CONCLUSIONS: The present meta-analysis suggested that there was no significant association between fish consumption and risk of renal cancer. More in-depth studies are warranted to report more detailed results, including stratified results by fish type, preparation method, and gender.

Association of vitamin D receptor FokI and ApaI polymorphisms with human cytomegalovirus disease in the first three months following kidney transplantation.

BACKGROUND: Untreated human cytomegalovirus (CMV) disease (CMVD) is an identified risk factor for reduced rates of patient (and graft) survival, death or retransplantation in kidney transplant recipients due to increased immunological tolerance after transplant. Vitamin D receptor (VDR) gene polymorphisms have an obvious relationship with autoimmune diseases but the relationship between VDR gene polymorphisms and CMVD are not well understood. This study investigated the relationship between VDR FokI and ApaI gene polymorphisms and CMVD, and their value for predicting risk of CMVD. METHODS: Ninety-eight kidney transplantation recipients were randomly chosen for which peripheral blood samples and case histories for the first three months after kidney transplantation were obtained. Using polymerase chain reaction-restriction fragment length polymorphisms, 30 recipients were found to be homozygous for the FokI gene (FF), 47 heterozygous (Ff), and 21 were homozygous (ff). Likewise, similar analyses determined that 12 recipients were homozygous for the ApaI gene (AA), 36 heterozygous (Aa), and 50 homozygous (aa). Factors affecting the prognosis of the kidney transplantation were compared for all genotypes by statistical analysis before operation. Infection by CMV for all recipients was detected by immunofluorescence assay to diagnose CMVD. RESULTS: No statistical significance was observed for the factors affecting the prognosis of the kidney transplantation between both genotypes; however, statistical differences in CMVD among the FokI genotypes were identified. It was determined that the risk of CMVD was significantly increased for recipients of the ff genotype than for other genotypes. There was no statistical significance observed for CMVD among ApaI genotypes. CONCLUSIONS: The recessive f allelic gene of VDR can be regarded as a risk factor of CMVD while FF recipients have lower incidence of CMVD after kidney transplantation. ApaI genotypes showed no relationship with predisposition to CMVD.

[Applications of monitoring human leukocyte antigen G and its inhibitory receptors in post-renal transplantation].

OBJECTIVE: to study the feasibility of human leucocyte antigen-G (HLA-G) as a post-transplantation prognostic biomarker and discuss the correlation of its receptor expression and the mechanisms. METHODS: a total of 215 recipients in our centre from February 2006 to June 2008 were divided into stable kidney function group (n = 173) and acute rejection group (n = 42). The soluble human leucocyte antigen-G5 (sHLA-G5) level in peripheral plasma was detected by ELISA. And the HLA-G receptor ILT-2, KIR2DL4 on T, B, NK lymphocytes were analyzed by flow cytometry (FCM). The sHLA-G5 cutoff level by ROC curve was employed to predict the events of acute post-transplantation rejection. And regression analysis was used to determine the association of sHLA-G5 with acute rejection. RESULTS: an optimal cutoff value of 139.0 microg/L could be defined for sHLA-G5 (sensitivity: 63.6%, specificity: 82.1%, AUC: 0.780). Binary regression analysis showed that sHLA-G5 played an independent role on acute rejection (P = 0.019, OR = 0.039, 95%CI: 2.091 - 5.661). The rate of HLA-G receptor ILT-2 on CD4(+)T cell, CD8(+)T cell and B cell in acute rejection group was statistically lower than that in stable kidney function group (21% ± 7% vs 52% ± 17%, 23% ± 6% vs 39% ± 16%, 21% ± 7% vs 39% ± 16%, all P < 0.05). The expression of KIR2DL4 on NK cells in acute rejection group was statistically lower than that in stable kidney function group (31% ± 10%vs 57% ± 21%, P < 0.05). CONCLUSION: sHLA-G5 level may be predicted for acute rejection with a high sensitivity and specificity. The up-regulated expression of ILT-2 and KIR2DLT may contribute to immunology tolerance in peripheral circulation.

Uptake of donor lymphocytes treated with 8-methoxypsoralen and ultraviolet A light by recipient dendritic cells induces CD4+CD25+Foxp3+ regulatory T cells and down-regulates cardiac allograft rejection.

Extracorporeal photopheresis (ECP) is an effective immunomodulatory therapy and has been demonstrated to be beneficial for graft-vs-host disease and solid-organ allograft rejection. ECP involves reinfusion of a patient's autologous peripheral blood leukocytes treated ex vivo with 8-methoxypsoralen and UVA light radiation (PUVA). Previous studies focused only on ECP treatment of recipient immune cells. Our study is the first to extend the target of ECP treatment to donor immune cells. The results of in vitro co-culture experiments demonstrate uptake of donor PUVA-treated splenic lymphocytes (PUVA-SPs) by recipient immature dendritic cells (DCs). Phagocytosis of donor PUVA-SPs does not stimulate phenotype maturation of recipient DCs. In the same co-culture system, donor PUVA-SPs enhanced production of interleukin-10 and interferon-gamma by recipient DCs and impaired the subsequent capability of recipient DCs to stimulate recipient naïve T cells. Phagocytosis of donor PUVA-SP (PUVA-SP DCs) by recipient DCs shifted T-cell responses in favor of T helper 2 cells. Infusion of PUVA-SP DCs inhibited cardiac allograft rejection in an antigen-specific manner and induced CD4(+)CD25(high)Foxp3(+) regulatory T cells. In conclusion, PUVA-SP DCs simultaneously deliver the donor antigen and the regulatory signal to the transplant recipient, and thus can be used to develop a novel DC vaccine for negative immune regulation and immune tolerance induction.

Rapamycin inhibits cholangiocyte regeneration by blocking interleukin-6-induced activation of signal transducer and activator of transcription 3 after liver transplantation.

Cholangiocyte proliferation is necessary for biliary recovery from cold ischemia and reperfusion injury (CIRI), but there are few studies on its intracellular mechanism. In this process, the role of rapamycin, a new immunosuppressant used in liver transplantation, is still unknown. In order to determine whether rapamycin can depress cholangiocyte regeneration by inhibiting signal transducer and activator of transcription 3 (STAT3) activation, rapamycin (0.05 mg/kg) was administered to rats for 3 days before orthotopic liver transplantation. The results indicated that cholangiocytes responded to extended cold preservation (12 hours) with severe bile duct injures, marked activation of the interleukin-6 (IL-6)/STAT3 signal pathway, and increased expression of cyclin D1 until 7 days after transplantation, and this was followed by compensatory cholangiocyte regeneration. However, rapamycin treatment inhibited STAT3 activation and resulted in decreased cholangiocyte proliferation and delayed biliary recovery after liver transplantation. On the other hand, rapamycin showed no effect on the expression of IL-6. We conclude that the IL-6/STAT3 signal pathway is involved in initiating cholangiocytes to regenerate and repair CIRI. Rapamycin represses cholangiocyte regeneration by inhibiting STAT3 activation, which might have a negative effect on the healing and recovery of bile ducts in grafts with extended cold preservation. Insights gained from this study will be helpful in designing therapy using rapamycin in clinical patients after liver transplantation.

[Impact of novel negative immunoregulatory dendritic cells on regulatory T cells in cardiac allograft recipient rats].

AIM: To investigate the effect of recipient dendritic cells (DC) loaded with PUVA-treated donor splenic lymphocytes (PUVA-SP) on CD4(+) CD25(+) regulatory T cells (Treg) and the survival time of cardiac allograft in rats. METHODS: Cardiac allografts from DA donor rats were transplanted into LEW recipient rats. Donor splenic lymphocytes were treated with 8-methoxypsoralen plus UVA irradiation (PUVA). Recipient bone marrow-derived DCs were co-cultured with PUVA-treated donor splenic lymphocytes (PUVA-SP) and the phenotype of the treated DCs was analyzed with flow cytometry. Seven days before transplantation, recipients were given infusion of recipient DCs loaded with PUVA-treated donor splenic lymphocytes (PUVA-SP DC) through the peripheral vein. The cardiac allograft survival time was evaluated by palpation every day. The frequency of CD4(+)CD25(+) T cells and CD4(+) CD25(high) T cells and their Foxp3 expression were analyzed using flow cytometry. Fourteen days after transplantation, T lymphocytes of the recipient rats receiving PUVA-SP DC were transferred to the normal LEW rats. The delayed type hypersensitivity (DTH) of the transferred LEW rats to the donor DA rats antigen then was measured. RESULTS: After co-cultured with PUVA-SP, recipient DCs still maintained an immature phenotype with low levels of MHC II, CD80 and CD86. The injection of PUVA-SP DCs significantly increased the frequencies of CD4(+)CD25(+) T cells and CD4(+) CD25(high) T cells and the expression of Foxp3 in the peripheral blood, and prolonged the allograft survival time. The donor antigen specific hyporesponsiveness could be transferred to normal LEW rats through adoptive transfusion. CONCLUSION: PUVA-SP DCs effectively up-regulate CD4(+) CD25(+) Foxp3(+) Treg and induce donor antigen specific hyporesponsiveness, thus prolonging the allograft survival time.

[Role of the activation of interleukin-6/STAT3 in cholangiocyte proliferation induced by cold ischemia reperfusion and injury].

OBJECTIVE: To investigate the role of IL-6/STAT3 pathway in the proliferation of cholangiocyte induced by cold ischemia and reperfusion injury. METHODS: Rats were randomized into CP 1 h and CP 12 h groups (supplied livers were preserved for 1 or 12 h), anti-IL-6R (rats in CP 12 h group were administrated with anti-rat soluble IL-6 receptor antibody), and control group. At 1, 3, 7, 14 d postoperative, IL-6 concentration in liver homogenate and cholangiocyte proliferation were detected by enzyme linked immunosorbent assay and histochemistry respectively. Expressions of IL-6 mRNA, phosphorylated-STAT3 and cyclin D1 protein in cholangiocytes were determined by real-time PCR or Western blot analysis. Serum concentrations of ALP and GGT and histology analysis were also performed. RESULTS: Minimal expressions of IL-6, p-STAT3 and cyclin D1 were detected in CP 1 h group, with a slight cholangiocytes proliferation. Cholangiocytes responded to extended cold preservation with severe bile duct injures and marked increase in IL-6 secretion, p-STAT3 and cyclin D1 protein expression, followed by compensatory cholangiocytes regeneration. Parallel to this observation, biochemical index and morphology indicated that bile duct injury was recovery at 14 d postoperative. However, anti-sIL-6R inhibited cholangiocytes proliferation and reduced the expressions of IL-6, STAT3 and cyclin D, with the cellular injury and increase of serum ALP or GGT. CONCLUSIONS: IL-6/STAT3 pathway might participate to initiate cholangiocytes regeneration after cold ischemia and preservation injury, which might benefit biliary recovery after liver transplantation.

[Risk factors of long-term cardiovascular diseases and cerebrovascular diseases in kidney allograft recipients].

OBJECTIVE: To identify the risk factors of cardiovascular diseases and cerebrovascular diseases (CVD) events in kidney allograft recipients. METHODS: We followed up 361 renal transplant recipients who had undergone renal transplantation in our center from January 2000 to December 2003 and evaluated the cumulative incidences and mortalities of CVD complications at baseline and post-transplantation 1, 3, 6, 12, 24, 36, 48, and 60 months. Kaplan-Meier plot was used to assess the incidence and Cox's proportional hazards model to determine the risk factors for cardiovascular complications. RESULTS: The cumulative incidences of CVD were 3.1%, 5.4%, 9.9%, 13.0%, 18.0%, 21.1%, and 24.1%, 1, 6, 12, 36, 48, and 60 months after transplantation, respectively. History of diabetes mellitus (RR 2.19, 95% CI 1.32-3.97, P = 0.009) and CVD (RR 6.34, 95% CI 3.76-14.60, P = 0.002) as well as the post-transplantation hypertension (RR 1.18, 95% CI 1.02-1.34, P = 0.04), diabetes mellitus (RR 2.82, 95% CI 1.33-7.26, P = 0.002), hyperlipidemia (RR 2.04, 95% CI 1.26-5.17, P = 0.008) and abnormal creatinine (> 200 micromol/L, RR 1.81, 95% CI 1.08-3.21, P = 0.03), and proteinuria (> 0.3 g/d , RR 1.56, 95% CI 1.12-3.54, P = 0.05) were independently correlated with the development of cardiovascular events. CONCLUSION: History of diabetes mellitus and CVD, post-transplant hypertension, diabetes mellitus, hyperlipidemia, abnormal creatinine and proteinuria are the independent risk factors of the development of CVD events.

[Pathogenesis of post-transplantation diabetes mellitus in 40 renal transplantation recipients].

OBJECTIVE: To explore pathogenesis of post-transplantation diabetes mellitus (PTDM) in renal transplantation recipients. METHODS: A total of 40 renal transplantation recipients were divided into three groups based on oral glucose tolerance test results: normal glucose tolerance (NGT) group (n = 10), impaired fasting glycaemia + impaired glucose tolerance (IFG + IGT) group (n = 16), and PTDM group (n = 14). Insulin resistance (IR) and beta cell function were assessed by homeostasis model. RESULTS: The differences of the immunosuppressive agents used in these groups were not statistically significant (P > 0.05). Compared with NGT group, insulin area under curve and homeostasis model assessment-insulin resistance index were significantly higher in IGT + IFG group and PTDM group (P < 0.05). Compared with NGT group and IGT + IPG group, insulin secretion index at 30 min and homeostasis model assessment-insulin secretion index were significantly lower in PTDM group (P < 0.05). CONCLUSION: Insulin resistance and beta-cell dysfunction may play a key role in the pathogenesis of PTDM.

[Role of IL-6/STAT3 in rat cholangiocyte proliferation induced by lipopolysaccharide].

OBJECTIVE: To investigate whether lipopolysaccharide (LPS) stimulates cholangiocyte proliferation via the IL-6/STAT3 pathway in vivo. METHODS: Rats were randomized into three groups: LPS group (injected intravenously with LPS 2.5 mg/kg), anti-IL-6 group (injected intravenously with anti-IL-6 0.5 mg/kg 1hr after LPS injection), and control group. At 6, 12, 24, 48 and 72 h after LPS injection, LPS concentration in plasma was detected by kinetic turbidimetric limulus test. IL-6 concentrations in liver homogenate was determinded by ELISA, cholangiocyte proliferation was checked by immunohistochemistry, expression of IL-6 mRNA was quantified by real-time RT-PCR, the level of phophorylated-STAT3 (P-STAT3) protein was analyzed by western blotting. RESULTS: Cholangiocytes responded to LPS by a marked increase in cell proliferation, IL-6 secretion and P-STAT3 expression. Anti-IL-6 neutralizing antibody inhibited LPS-induced cholangiocytes proliferation, and decreased levels of IL-6 and p-STAT3. CONCLUSIONS: LPS promotes cholangiocyte proliferation through the IL-6/STAT3 pathway.

Activation of interleukin-6/STAT3 in rat cholangiocyte proliferation induced by lipopolysaccharide.

BACKGROUND: Cholangiocytes are exposed to endotoxins (lipopolysaccharide, LPS) in a variety of biliary inflammations. It is known that LPS enhances the release of interleukin (IL)-6, a potent cholangiocyte mitogen. However, the role of LPS in cholangiocyte proliferation in vivo is unknown. Aims To investigate whether LPS stimulates cholangiocyte proliferation in vivo via the IL-6/STAT3 pathway. METHODS: Rats were randomized into four groups: the LPS group (injected intravenously with LPS 2.5 mg/kg), anti-IL-6 group (injected intravenously with anti-IL-6 0.5 mg/kg 1 h after LPS injection), RPM group (treated with RPM 0.4 mg/kg intraperitoneally 30 min before LPS injection), and control group. At 6, 12, 24, 48, and 72 h after LPS injection, LPS in plasma was detected by kinetic turbidimetric limulus test. IL-6 concentrations in liver homogenate and cholangiocyte proliferation were determined by ELISA or immunohistochemistry, respectively. Expression of IL-6 mRNA and phosphorylated-STAT3 (P-STAT3) protein in cholangiocytes was analyzed by real-time RT-PCR and western blotting. RESULTS: Cholangiocytes responded to LPS by a marked increase in cell proliferation, IL-6 secretion, and P-STAT3 expression. Anti-IL-6 neutralizing antibody inhibited LPS-induced proliferation of cholangiocytes and decreased levels of IL-6 and STAT3. Furthermore, after being treated with RPM, STAT3 activation was also depressed, which resulted a decreased proliferation of cholangiocytes. CONCLUSIONS: LPS promotes cholangiocyte proliferation through the IL-6/STAT3 pathway, while RPM shows a depressive effect in this pathway.

Short-term anti-CD25 monoclonal antibody treatment and neogenetic CD4(+)CD25(high) regulatory T cells in kidney transplantation.

CD4(+)CD25(high) T cells named regulatory T (Treg) cells are generated and play a key role in the induction and maintenance of transplant tolerance in organ recipients. Interleukin-2 (IL-2) enhance the development of effector cells and is essential for generation of Treg cells. The effect of the anti-CD25 monoclonal antibody (anti-CD25mAb) induction therapy on the neogenetic CD4(+)CD25(high)Treg cells is important for therapeutic strategies in kidney transplant. To clarify the question, a prospective study was conducted in 21 living donor kidney transplant recipients who randomly divided into the anti-CD25mAb group (Daclizumab) with 11 patients and the control group with 10 patients. The frequency of CD4(+)CD25(high)Treg cells in total CD4(+) T cells was analyzed by flow cytometry and FoxP3 expression by RT-PCR in peripheral blood, and results were compared at day 0, 3, 13, 17, 27 posttransplantation. There was no significant difference in patient characteristics and allograft survival. The present study showed that in vivo antigen-specific Treg cells population were generated and expanded after transplant. Both groups showed a significant increase in the frequency of CD4(+)CD25(high)Treg cells and higher level of FoxP3 mRNA after transplantation while the serum creatinine declined. Compared with the control group, recipients with anti-CD25mAb injection had significantly lower percentage of CD4(+)CD25(high) in total CD4(+) cells (1.13%+/-0.13% vs 1.94%+/-0.22%, P=0.00; 3.75%+/-0.28% vs 7.11%+/-0.51%, P=0.00) on day 3, 17 after transplantation. While, the percentage was not significantly different on day 10, 27 (3.72%+/-0.19% vs 4.36%+/-0.28%, P=0.08; 7.84%+/-0.35% vs 8.56%+/-0.36%, P=0.16). However, there was not obvious difference in Foxp3 expression level associated with the source of the CD4(+)CD25(high)Treg cells at the different time point after transplant. Our data indicated that CD4(+)CD25(high)Treg cells were transiently affected by anti-CD25mAb, without depletion. In conclusion, the short-term treatment with anti-CD25mAb might not prevent the production, proliferation of neogenetic Treg cells in organ transplant.

Endothelial cell chimerism by fluorescence in situ hybridization in gender mismatched renal allograft biopsies.

BACKGROUND: The blood vessels of a transplanted organ are the interface between donor and recipient. The endothelium in the blood vessels is thought to be the major target for graft rejection. Endothelial cells of a transplanted organ can be of recipient origin after transplantation. In this study, we tested whether endothelial chimerism correlated with the graft rejection and cold ischemia. METHODS: We studied the biopsy samples from 34 renal transplants of female recipients who received the kidney from a male donor for the presence of endothelial cells of recipient origin. We examined the tissue sections of renal biopsy samples by fluorescence in situ hybridization (FISH) for the presence of endothelial cells containing two X chromosomes using a biotinylated Y chromosome probe and digoxigenin labelled X chromosome probe, and then analyzed the relationship between the endothelial cell chimerism and the rejection and cold ischemia. RESULTS: Endothelial chimerism was common and irrespective of rejections (P > 0.05). The cold ischemic time of chimerism group was longer than no chimerism group ((14.83 +/- 4.03) hours vs (11.27 +/- 3.87) hours, P < 0.05). CONCLUSIONS: There is no correlation between the percentage of recipient endothelial cells in vascular endothelial cells and the type of graft rejection. The endothelium damaged by ischemic injury might be repaired by the endothelial cells from the recipient.