Development and validation of a novel nomogram model for predicting delayed graft function in deceased donor kidney transplantation based on pre-transplant biopsies.

BACKGROUND: Delayed graft function (DGF) is an important complication after kidney transplantation surgery. The present study aimed to develop and validate a nomogram for preoperative prediction of DGF on the basis of clinical and histological risk factors. METHODS: The prediction model was constructed in a development cohort comprising 492 kidney transplant recipients from May 2018 to December 2019. Data regarding donor and recipient characteristics, pre-transplantation biopsy results, and machine perfusion parameters were collected, and univariate analysis was performed. The least absolute shrinkage and selection operator regression model was used for variable selection. The prediction model was developed by multivariate logistic regression analysis and presented as a nomogram. An external validation cohort comprising 105 transplantation cases from January 2020 to April 2020 was included in the analysis. RESULTS: 266 donors were included in the development cohort, 458 kidneys (93.1%) were preserved by hypothermic machine perfusion (HMP), 96 (19.51%) of 492 recipients developed DGF. Twenty-eight variables measured before transplantation surgery were included in the LASSO regression model. The nomogram consisted of 12 variables from donor characteristics, pre-transplantation biopsy results and machine perfusion parameters. Internal and external validation showed good discrimination and calibration of the nomogram, with Area Under Curve (AUC) 0.83 (95%CI, 0.78-0.88) and 0.87 (95%CI, 0.80-0.94). Decision curve analysis demonstrated that the nomogram was clinically useful. CONCLUSION: A DGF predicting nomogram was developed that incorporated donor characteristics, pre-transplantation biopsy results, and machine perfusion parameters. This nomogram can be conveniently used for preoperative individualized prediction of DGF in kidney transplant recipients.

Donor-specific antibodies, glomerulitis, and human leukocyte antigen B eplet mismatch are risk factors for peritubular capillary C4d deposition in renal allografts.

BACKGROUND: The complement system plays an important role in the immune response to transplantation, and the diagnostic significance of peritubular capillary (PTC) C4d deposition (C4d+) in grafts is controversial. The study aimed to fully investigate the risk factors for PTC C4d+ and analyze its significance in biopsy pathology of kidney transplantation. METHODS: This retrospective study included 124 cases of kidney transplant with graft biopsy and donor-specific antibody (DSA) testing from January 2017 to December 2019 in a single center. The effects of recipient pathological indicators, eplet mismatch (MM), and DSAs on PTC C4d+ were examined using univariate and multivariate logistic regression analyses. RESULTS: In total, 35/124 (28%) were PTC C4d+, including 21 with antibody-mediated rejection (AMR), eight with renal tubular injury, three with T cell-mediated rejection, one with glomerular disease, and two others. Univariate analysis revealed that DSAs (P < 0.001), glomerulitis (P < 0.001), peritubular capillaritis (P < 0.001), and human leukocyte antigen (HLA) B eplet MM (P = 0.010) were the influencing factors of PTC C4d+. According to multivariate analysis, DSAs (odds ratio [OR]: 9.608, 95% confidence interval [CI]: 2.742-33.668, P < 0.001), glomerulitis (OR: 3.581, 95%CI: 1.246-10.289, P = 0.018), and HLA B eplet MM (OR: 1.166, 95%CI: 1.005-1.353, P = 0.042) were the independent risk factors for PTC C4d+. In receiver operating characteristic curve analysis, the area under the curve was increased to 0.831 for predicting PTC C4d+ when considering glomerulitis, DSAs, and HLA B eplet MM. The proportions of HLA I DSAs and PTC C4d+ in active antibody-mediated rejection were 12/17 and 15/17, respectively; the proportions of HLA class II DSAs and PTC C4d+ in chronic AMR were 8/12 and 7/12, respectively. Furthermore, the higher the PTC C4d+ score was, the more serious the urinary occult blood and proteinuria of recipients at the time of biopsy. CONCLUSIONS: PTC C4d+ was mainly observed in AMR cases. DSAs, glomerulitis, and HLA B eplet MM are the independent risk factors for PTC C4d+.

Different roles of bortezomib and ONX 0914 in acute kidney injury.

Proteasome inhibitor bortezomib offers one more option for acute or chronic antibody-mediated rejection after kidney transplantation, but aggravated acute kidney injury (AKI) in some cases early after surgery using bortezomib bring new problem. Here, we evaluated the effects of bortezomib and ONX-0914 on renal tubule injury in a mouse model of ischemia-reperfusion injury. After treated with bortezomib, serum creatinine, usea nitrogen and tubular necrosis significantly increased compared with vehicle-treated mice, but decreased in ONX-0914 group mildly. Infiltration of neutrophil and macrophage were less in bortezomib and ONX-0914-treated mice than vehicle-treated group, and the same was observed on oxidative stress in the kidneys. Furthermore, the apoptosis of renal tubular epithelial cells increased in bortezomib-treated mice' kidneys compared with ONX-0914 and vehicle-treated controls. In vitro HK2 cell experiments also demonstrated the proapoptotic effect of bortezomib. The mRNA expression of several proapoptotic factors increased in kidneys of bortezomib-treated mice. In brief, bortezomib, as a proteasome inhibitor, shows a certain cytotoxicity to renal tubular epithelial cell during ischemia/reperfusion injury (IRI) through increased apoptosis. ONX-0914, as an immunoproteasome inhibitor, showed equal potency on anti-inflammation and oxidative stress relieving compared with bortezomib, while less cytotoxicity. The results render the immunoproteasome is a better target for anti-rejection and protecting kidney function in the field of organ transplantation.

Prediction of kidney transplant outcome based on different DGF definitions in Chinese deceased donation.

BACKGROUND: Delayed graft function (DGF) is an important complication of kidney transplantation and can be diagnosed according to different definitions. DGF has been suggested to be associated with the long-term outcome of kidney transplantation surgery. However, the best DGF definition for predicting renal transplant outcomes in Chinese donations after cardiac death (DCDs) remains to be determined. METHOD: A total of 372 DCD kidney transplant recipients from June 2013 to July 2017 in the First Affiliated Hospital of Xi'an Jiaotong University were included in this retrospective study to compare 6 different DGF definitions. The relationships of the DGF definitions with transplant outcome were analyzed, including graft loss (GL) and death-censored graft loss (death-censored GL). Renal function indicators, including one-year estimated glomerular filtration rate (eGFR) and three-year eGFR, and were compared between different DGF groups. RESULTS: The incidence of DGF varied from 4.19 to 35.22% according to the different DGF diagnoses. All DGF definitions were significantly associated with three-year GL as well as death-censored GL. DGF based on requirement of hemodialysis within the first week had the best predictive value for GL (AUC 0.77), and DGF based on sCr variation during the first 3 days post-transplant had the best predictive value for three-year death-censored GL (AUC 0.79). Combination of the 48-h sCr reduction ratio and classical DGF can improve the AUC for GL (AUC 0.85) as well as the predictive accuracy for death-censored GL (83.3%). CONCLUSION: DGF was an independent risk factor for poor transplant outcome. The combination of need for hemodialysis within the first week and the 48-h serum creatinine reduction rate has a better predictive value for patient and poor graft outcome.

B-Cell Activating Factor Predicts Acute Rejection Risk in Kidney Transplant Recipients: A 6-Month Follow-Up Study.

B cell activating factor (BAFF) belonging to TNF family is a cytokine that enhances B-cell proliferation and differentiation. Recently, It has been suggested that BAFF might be a potential therapeutic target for treating autoimmune disease. However, the relationship between BAFF and allograft rejection is controversial, and the clinical significance of BAFF in predicting allograft rejection need to be further explored. We conducted 6-month follow-up study to confirm the hypothesis that BAFF might be a risk factor for predicting acute rejection in kidney transplant recipients. At the end of the study, a total of 155 kidney transplant recipients were recruited from October 2015 to October 2017, and classified into acute rejection group (n = 34) and stable renal function group (n = 121) according to their clinical course. We demonstrate that the serum BAFF levels when acute rejection occurred was significantly higher than that in the stable renal function group (2426.19 ± 892.19 vs. 988.17 ± 485.63 pg/mL, P < 0.05). BAFF expression was significantly enhanced in the membrane and cytoplasm of renal tubule epithelial cells in the transplant kidney tissue with acute rejection, and a positive correlation between BAFF and C4d expression was also observed (r = 0.880, P = 0.001). ROC analyses highlight the superiority of serum BAFF level before transplant over those on other post-transplant days in prediction of acute rejection episodes. The sensitivity, specificity and AUC (area under curve) were 83.3, 89.5, and 0.886%, respectively. Kaplan-Meier survival analysis showed that recipients with higher pretransplant BAFF levels had higher acute rejection incidence (P = 0.003). In conclusion, we have identified that BAFF levels are associated with the acute rejection and could be a promising biomarker to predict kidney transplant rejection risks.

Arctigenin: A two-edged sword in ischemia/reperfusion induced acute kidney injury.

Arctigenin (ATG) is one of the main active substances in fruit derived from Arctium lappa L. Previous studies have reported that ATG have antitumor, neuroprotective, antioxidant, antifibrosis and anti-inflammatory functions. However, the actions of ATG in kidney with acute injury following ischemia/ reperfusion (I/R) is still uncertain. In our study, mice were subjected to kidney I/R by having the kidney pedicles clamped and administered with vehicle or ATG (1, 3 or 9 mg/kg/d) via oral gavage for 7 consecutive days prior to I/R. Notably, ATG aggravated kidney I/R injury with the concentration increases. Multiple biochemical assays and histological examination showed ATG significantly alleviated the inflammatory response as reflected by a decreased expression of proinflammatory cytokine, TLR4/MyD88, and NF-κB, along with the infiltration of CD68+ macrophage and CD11b+Gr1+ neutrophil in the kidneys. Meanwhile, ATG alleviated I/R-induced oxidative stress proved by increasing kidney manganese superoxide dismutase and glutathione peroxidase activity but reducing levels of malonaldehyde and inducible nitric oxide synthase. On the contrary, apoptosis was significantly increased in kidneys of ATG-treated mice compared with vehicle-treated controls, especially in tubular cells. There were increased numbers of TUNEL positive cells and increased Bcl-2, Bax, cleaved-caspase-3, and cleaved-caspase-9 expression. The current study demonstrates that pretreatment of ATG aggravates I/R induced acute kidney injury by increasing apoptosis of tubular cells despite reducing infiltrating inflammatory cells and proinflammatory cytokine.

Early Immunosuppressive Exposure of Enteric-Coated-Mycophenolate Sodium Plus Tacrolimus Associated with Acute Rejection in Expanded Criteria Donor Kidney Transplantation.

BACKGROUND: Immunosuppressive agents are still inefficient in preventing biopsy-proven acute rejection (BPAR) after expanded criteria donor (ECD) kidney transplantation. The aim of this study was to investigate the relationships between early immunosuppressive exposure and the development of BPAR. METHODS: We performed a retrospective study of 58 recipients of ECD kidney transplantation treated with enteric-coated-mycophenolate sodium, tacrolimus (Tac), and prednisone. The levels of mycophenolic acid-area under the curve (MPA-AUC)0-12h and Tac C0were measured at the 1st week and the 1st month posttransplant, respectively. The correlation was assessed by multivariate logistic regression. RESULTS: The occurrence rates of BPAR and antibody-mediated rejection were 24.1% and 10.3%, respectively. A low level of MPA-AUC0-12h at the 1st week posttransplant was found in BPAR recipients (38.42 ± 8.37 vs. 50.64 ± 13.22, P < 0.01). In addition, the incidence of BPAR was significantly high (P < 0.05) when the MPA-AUC0-12hlevel was <30 mg·h-1·L-1 at the 1st week (15.0% vs. 44.4%) or the Tac C0was <4 ng/ml at the 1st month posttransplant (33.3% vs. 21.6%). Multivariable logistic regression analysis showed that the MPA-AUC0-12h at the 1st week (OR: 0.842, 95% CI: 0.784-0.903) and the Tac C0at the 1st month (OR: 0.904, 95% CI: 0.822-0.986) had significant inverse correlation with BPAR (P < 0.05). CONCLUSIONS: Low-level exposure of MPA and Tac C0in the early weeks posttransplant reflects an increased acute rejection risk, which suggested that MPA-AUC0-12h <30 mg·h-1·L-1 and Tac C0 <4 ng/ml should be avoided in the first few weeks after transplantation.

Knockdown of NLRC5 attenuates renal I/R injury in vitro through the activation of PI3K/Akt signaling pathway.

NLRC5, as the largest member of nucleotide-binding domain and leucine-rich repeat (NLR) family, was involved in various physiological processes, such as inflammation, fibrosis, innate immunity and diabetic nephropathy. However, the role of NLRC5 in acute kidney injury remains unclear. The aim of this study was to investigate the role of NLRC5 in human renal proximal tubular epithelial cells (HK-2) exposed to hypoxia/reoxygenation (H/R). Our results demonstrated that the expression of NLRC5 was significantly up-regulated in HK-2 cells exposed to H/R. Knockdown of NLRC5 significantly improved the viability of HK-2 cells exposed to H/R. In addition, knockdown of NLRC5 efficiently inhibited H/R-induced oxidative stress and apoptosis in HK-2 cells. Mechanistically, knockdown of NLRC5 markedly enhanced the activation of PIK3/Akt signaling pathway in H/R-stimulated HK-2 cells. In summary, our findings indicate that knockdown of NLRC5 attenuates renal I/R injury in vitro through the activation of PI3K/Akt signaling pathway.

Comparison of the characteristics of macrophages derived from murine spleen, peritoneal cavity, and bone marrow.

Macrophages have a diverse set of functions based upon their activation states. The activation states, including resting (M0) and polarizing (M1 and M2) states, of macrophages derived from the mouse bone marrow, spleen, and peritoneal cavity (BMs, SPMs, and PCMs, respectively) were compared. We evaluated the macrophage yield per mouse and compared the surface markers major histocompatibility complex (MHC) II and CD86 by flow cytometry. The relative mRNA levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, mannose receptor (MR), and Ym1 in the M0, M1, and M2 states were also compared using real-time polymerase chain reaction (PCR) analysis. Bone marrow yielded the most macrophages with the best homogeneity, but they were polarized toward the M2 phenotype. All three types of macrophages had the capacity to polarize into the M1 and M2 states, but SPMs had a stronger capacity to polarize into M1. The three types of macrophages showed no differences in their capacity to polarize into the M2 state. Therefore, the three types of macrophages have distinct characteristics regardless of their resting or polarizing states. Although bone marrow can get large amounts of homogeneous macrophages, the macrophages cannot replace tissue-derived macrophages.

[Evaluation of immune status of kidney transplant recipients by combined HLA-G5 and sCD30].

OBJECTIVE: to study the relationship between the expression of serum human leucocyte antigen-G5 (HLA-G5)/soluble CD30 (sCD30) and the function of renal graft in kidney transplant recipients and investigate the immune status of recipients with combined HLA-G5 and sCD30. METHODS: from January 2002 to November 2008, a total of 66 kidney transplant recipients in our centre were selected as subjects and divided into three groups: stable function of renal graft (n = 38), acute rejection (n = 15) and chronic rejection (n = 13). The expressions of serum HLA-G5 and sCD30 were detected. There were two different immune conditions with acute/chronic allograft rejection and normal renal graft in kidney transplant recipients as evaluated by combined HLA-G5 and sCD30. The sensitivity, specificity and critical value of the method were analyzed by the curve of receiver operating characteristic. RESULTS: the levels of HLA-G5 and sCD30 were significantly correlated with serum creatinine (r = -0.493, 0.691, both P < 0.01). Within the first year post-transplantation, the sensitivity was 78.6% and the specificity 85.7% when HLA-G5 critical value 82 microg/L and sCD30 critical value 12.2 microg/L. After one year post-transplantation: the sensitivity was 92.3% and the specificity 84.6% when HLA-G5 critical value 141 microg/L and sCD30 critical value 10.3 microg/L. CONCLUSION: the immune state of recipients are evaluated by combine HLA-G5 and sCD30 which may be a simple and valid method.

[Comparison of different isolation methods on adult Sertoli cells co-transplanted with islets].

AIM: To establish a more convenient and effective method for isolating adult Sertoli cells and apply the method to islet transplantation. METHODS: Trypsin, DNase, collagenase and hyaluronidase were used for a one-step digestion in group A. A two-step digestion was used in group B, in which testis tissues were first digested by trypsin and DNase and then were digested by collagenase and hyaluronidase. In group C, trypsin and DNase were used in the first step of digestion, hyaluronidase was used in the second step and collagenase was used in the third step. Sertoli cells were identified by morphology and immunohistochemistry and the viability and purity of Sertoli cells were detected by MTT and flow cytometry (FCM). Expression of Fas-L was detected by Western blot and the effects of the co-transplantation of islets and Sertoli cells were compared between the three groups. RESULTS: Typical Sertoli cells were seen after isolation using the three different methods. Sertoli cells isolated by method A and method B were large in number while those isolated by method B and method C were pure. The results of MTT showed that the viability of Sertoli cells in group B was significantly higher than that in group A and group C (P<0.05) and Western blot results showed that expression of Fas-L on Sertoli cells in group B was significantly stronger than that in group A and group C (P<0.05). The purity of Sertoli cells detected by FCM in group B and group C were significantly higher than that in group A (P<0.05). The survival of islets co-transplanted with Sertoli cells to renal capsule of diabetic mice was significantly longer in group B compared with that in control group as well as in group A and group C (P<0.05). CONCLUSION: Sertoli cells obtained by the two-step digestion method are of higher purity and viability, which significantly prolong the survival of islet graft by co-transplantation.

Study on systemic immune tolerance induction in rat islet transplantation by intravenous infusion of Sertoli cells.

BACKGROUND: Sertoli cells are usually co-transplanted with pancreatic islets to induce local immune tolerance. In this report, we used infusion with Sertoli cells in islet transplantation to induce systemic immune tolerance and studied the mechanism of the tolerance induction. METHODS: Streptozotocin-induced diabetic rats were divided into four groups before islet transplantation: group A as control; group B with intravenous infusion of Sertoli cells; group C with Sertoli cell infusion and Fas ligand antibody treatment; and group D with Sertoli cell infusion and transforming growth factor-beta1 antibody treatment. The mean survival time (MST) and insulin expression of islet grafts were measured. The number of lymphocytes and the levels of cytokines in peripheral blood were also measured. RESULTS: Group B had the longest MST of islet allografts (41.6+/-4.20 days) followed by groups C, D, and A (P<0.05). Immunohistochemistry showed similar results with MST. The rats in group B had the least CD4 T cells (only 15.6%+/-6.4%) compared with other groups (P<0.05). The numbers of CD8 T cells in rats of groups B (11.2%+/-4.3%) and D (14.5%+/-5.6%) were significantly lower than those of groups A and C (P<0.05). After transplantation, group B's interleukin (IL)-2 level (1.92+/-0.68 ng/mL) was found to be significantly lower than that of other groups (P<0.05). Interferon-gamma showed similar pattern of change as IL-2 (P<0.05). Groups A and D had significantly lower levels of IL-4 (4.31+/-1.97 pg/mL 4.69+/-1.33 pg/mL, respectively) than groups B and C (P<0.05). CONCLUSION: Infusion of Sertoli cells could effectively prolong the survival of islet grafts and reduce peripheral blood lymphocyte and cytokine levels. In this process, transforming growth factor-beta1 played a major role and Fas ligand played a smaller additional role.

[Immature dendritic cells directional differentiated from murine hemopoietic stem cells and morphous and function of them by MACS].

AIM: To Investigate a method that can obtain massive highly purified immature dendritic cells(imDCs) steadily in vitro, and identify them by morphous, function and surface markers by MACS. METHODS: Isolate and purify CD117(+) hemopoietic stem cells(HSCs) from bone marrow of healthy C57 murine by MACS. After being expanded by SCF+IL-3, HSCs would be directional differentiated into imDCs by use of cytokine scheme of GM-CSF+IL-4+IL-10. Then identify imDCs through following ways: observing morphous and function of them under inverted microscope, scanning electron microscope and transmission electron microscope, detecting the expression of surface markers by flow cytometry. RESULTS: The fold of expansion 3, 5 and 7 days after cultured with SCF+IL-3 was separately 10.34 +/- 1.43, 22.65 +/- 2.71 and 54.39 +/- 3.08. HSCs can be successfully differentiated into imDCs, which have the function of phagocytosis. The imDCs were short and small, in shape of sentus. The expression of surfacee markers was CD11c(+), I-A/I-E(low), CD40(-), CD80(-), CD86(-) by flow cytometry. CONCLUSION: This method can obtain and identify massive highly purified imDCs steadily in vitro.

[Directional differentiation of murine CD117+ hemopoietic stem cells into immature dendritic cells and their identification].

OBJECTIVE: To establish a stable method for obtaining large quantity of highly purified immature dendritic cells (imDCs) in vitro, and identify the morphology, function and surface markers of the cells. METHODS: CD117(+) hemopoietic stem cells (HSCs) were isolated and purified from the bone marrow of healthy C57 mice by magnetic affinity cell sorting. After cell expansion by treatment with stem cell factor (SCF) and interleukin-3 (IL-3), the HSCs were induced for directional differentiation into imDCs by treatment with GM-CSF, IL-4 and IL-10. The imDCs obtained were identified by morphological and functional observation under inverted microscope, scanning electron microscope and transmission electron microscope, followed by detection of the expressions of the surface markers using flow cytometry. RESULTS: After 3, 5 and 7 days of culture in the presence of SCF+IL-3, the cells were expanded by 10.34-/+1.43, 22.65-/+2.71 and 54.39-/+3.08 folds, respectively. The HSCs were successfully induced to differentiate into imDCs with phagocytotic activity. The dendrites of the imDCs were short small, and appearing spinous. The expressions of surface markers were detected from the cells showing the phenotype of CD11c(+), I-A/I-E(low), CD40(-), CD80(-), CD86(-). CONCLUSION: The method described allows steadily acquisition of large quanty of highly purified imDCs and of their effective identification in vitro.