Chronic Allograft Nephropathy Research Articles

Neutrophil gelatinase-associated lipocalin (NGAL) is localised to the primary cilium in renal tubular epithelial cells - A novel source of urinary biomarkers of renal injury

BackgroundPrimary cilia have been shown to play a central role in regulating epithelial cell differentiation during injury and repair. Growing evidence implicates structural and functional abnormalities of primary cilia in kidney epithelial cells in the onset and development of various kidney diseases including polycystic kidney disease (PKD). Neutrophil-gelatinase associated lipocalin (NGAL) has been identified as a reliable urinary biomarker of kidney injury. However, the mechanism by which this protein accumulates in patient urine samples has not been fully elucidated. MethodsHuman renal tubular epithelial cells (RPTECs) were exposed to previously characterized deciliating agents to assess mechanisms of primary cilium loss. Confocal immunofluorescent imaging was employed to visualise the effects on cilia. Western blot analysis was utilised to quantify the ciliary protein Arl13b in both RPTEC whole cell lysates and supernatants. Co-immunoprecipitation was used to demonstrate co-localisation of Arl13b and NGAL in urinary samples from a clinical Chronic Allograft Nephropathy (CAN) cohort. ResultsImmunofluorescent analysis revealed that NGAL was localised to the primary cilium in RPTECs, co-localizing with a ciliary specific protein, Arl13b. Deciliation experiments showed that loss of the cilia coincided with loss of NGAL from the cells. ConclusionThe accumulation of NGAL in supernatants in vitro and in the urine of CAN patients was concurrent with loss of Arl13b, a specific ciliary protein. The findings of this study propose that increased NGAL urinary concentrations are directly linked to deciliation of the renal epithelial cells as a result of injury.

Long-Term Outcomes after Acute Rejection in Kidney Transplant Recipients: An ANZDATA Analysis.

Declining rates of acute rejection (AR) and the high rate of 1-year graft survival among patients with AR have prompted re-examination of AR as an outcome in the clinic and in trials. Yet AR and its treatment may directly or indirectly affect longer-term outcomes for kidney transplant recipients. To understand the long-term effect of AR on outcomes, we analyzed data from the Australia and New Zealand Dialysis and Transplant Registry, including 13,614 recipients of a primary kidney-only transplant between 1997 and 2017 with at least 6 months of graft function. The associations between AR within 6 months post-transplant and subsequent cause-specific graft loss and death were determined using Cox models adjusted for baseline donor, recipient, and transplant characteristics. AR occurred in 2906 recipients (21.4%) and was associated with graft loss attributed to chronic allograft nephropathy (hazard ratio [HR], 1.39; 95% confidence interval [95% CI], 1.23 to 1.56) and recurrent AR beyond month 6 (HR, 1.85; 95% CI, 1.39 to 2.46). Early AR was also associated with death with a functioning graft (HR, 1.22; 95% CI, 1.08 to 1.36), and with death due to cardiovascular disease (HR, 1.30; 95% CI, 1.11 to 1.53) and cancer (HR, 1.35; 95% CI, 1.12 to 1.64). Sensitivity analyses restricted to subgroups with either biopsy-proven, antibody-mediated, or vascular rejection, or stratified by treatment response produced similar results. AR is associated with increased risks of longer-term graft failure and death, particularly death from cardiovascular disease and cancer. The results suggest AR remains an important short-term outcome to monitor in kidney transplantation and clinical trials.

SUN-116 ANGIOTENSIN RECEPTOR BLOCKERS DOWN REGULATE PROFIBROTIC GENE EXPRESSION

Chronic allograft nephropathy is the major pathologic finding in late onset allograft dysfunction which is characterized by interstitial fibrosis and tubular atrophy (IF/TA). The main players in the process of fibrosis are transforming growth factor β (TGF- β) and miR-21 expression with a bidirectional interplay. In this study we evaluated the effects of Angiotensin Receptor type 1 antagonist, Losartan, on peripheral blood and tissue expression of TGF- β and miR-21 and histologic findings in allograft biopsy in kidney transplant recipients. In a randomized clinical trial fifty-four patients were enrolled and divided randomly into two groups. Group 1 was treated with a daily dose of 25 mg Losartan and group 2 as control. Blood sampling was done at 48 hours post-transplantation, 3rd month and 6th month after transplantation for measurement of TGF- β RNA and miR-21. Protocol biopsy was performed at 6th month post-transplantation for RNA extraction and histologic evaluation of IF/TA. Tabled 1ParametersCase groupControl groupTime48 hours3months6months48hours3months6monthsmiR-210.6450.7360.8550.6621.0291.560TGF- β6.7255.3794.5466.9386.7277.752 Open table in a new tab Although patients were not different initially, those underwent treatment with losartan had lower miR-21 and TGF- β levels in circulating PBMCs, and there was a decrescendo trend in peripheral blood TGF- β levels during the 6-month follow up. Tissue expression of miR-21 and TGF- β was also considerably lower among losartan treated patients at the time of tissue biopsy. Losartan treatment decreased the tissue expression of miR-21 and TGF- β and tissue fibrosis (IF/TA) in kidney transplant patient, and had a protective effect on allograft function and may delay chronic allograft dysfunction by reducing mediators of fibrosis.

Application of intravoxel incoherent motion diffusion weighted imaging for assessment of early chronic allograft nephropathy

To investigate the feasibility and clinical application of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) technique in non-invasive assessment for early chronic allograft nephropathy (CAN). Methods: A total of 23 renal allograft recipients were recruited from inpatients or outpatients according to the inclusion and exclusion criteria for this study. Recipients were divided into a CAN group (n=12, pathologically confirmed early CAN patients) and a control group (n=11, volunteers with long-term stable renal function). Abdominal MRI was performed on patients of renal allograft with a multi-b value DWI sequence. IVIM2b-new software was used for obtaining the IVIM-DWI quantitative parameter pseudo-color maps and the values of IVIM-DWI of renal parenchyma, including the pure diffusion coefficient (D), perfusion correlation diffusion coefficient (D*) and perfusion fraction (f). The IVIM quantitative parameters between the two groups were compared using independent sample t test. ROC analysis was performed when the differences in parameter were statistically significant and the area under curve (AUC) was calculated. Results: In IVIM bi-exponential analysis, The D value was significantly decreased in the CAN group compared with the control group (P<0.05), whereas there are no significantly difference in value of D* and f between the two groups (all P>0.05). The AUC of D value for distinguishing the early CAN from the control were 0.784 with sensitivity and specificity at 58.3% and 90.9%, respectively. Conclusion: The IVIM-DWI quantitative parameter D can non-invasively assess early CAN to some extent. IVIM-DWI technique is expected to be an effective, easy and non-invasive method to detect early CAN, and assist early diagnose as well as dynamically monitor CAN.

Gremlin, A Potential Urinary Biomarker of Anca-Associated Crescentic Glomerulonephritis

Gremlin renal overexpression has been reported in diabetic nephropathy, pauci-immune crescentic glomerulonephritis and chronic allograft nephropathy and has been implicated in the pathophysiology of the progression of renal damage. However, it is unknown whether urinary Gremlin can be associated with renal functional status, renal biopsy findings and outcome. To examine these associations we studied 20 patients with ANCA+ renal vasculitis and very high urinary Gremlin (354 ± 76 ug/gCr), 86 patients with other glomerular diseases and moderately elevated urinary Gremlin (83 ± 14 ug/gCr) and 11 healthy controls (urinary Gremlin 11.3 ± 2.4 ug/gCr). Urinary Gremlin was significantly correlated with renal expression of Gremlin (r = 0.64, p = 0.013) observed in cellular glomerular crescents, tubular epithelial cells and interstitial inflammatory cells. Moreover, urinary Gremlin levels were correlated with the number of glomerular crescents (r = 0.53; p < 0.001), renal CD68 positive cells (r = 0.71; p < 0.005), tubulointerstitial fibrosis (r = 0.50; p < 0.05), and serum creatinine levels (r = 0.60; p < 0.001). Interestingly, Gremlin expression was colocalized with CD68, CD163 (monocyte/macrophage markers) and CCL18 positive cells. ROC curve analysis showed that the cutoff value of urinary Gremlin in glomerular diseases as 43 ug/gCr with 72% of sensitivity and 100% of specificity [AUC: 0.96 (CI 95% 0.92–0.99] (p < 0.001). For ANCA+ renal vasculitis the value of urinary Gremlin of 241 ug/gCr had 55% of sensitivity and 100% of specificity [AUC: 0.81 (CI 95% 0.68–0.94) (p < 0.001]. Based on these results we propose that urinary Gremlin represents a non-invasive biomarker in ANCA+ renal vasculitis, and suggest a role of Gremlin in the formation of crescents.

Correlation between shear wave velocity of renal parenchyma and TGF-β1 in chronic allograft nephropathy

Objective To evaluate the change of shear wave velocity (SWV) of renal parenchyma and serum level of transforming growth factor beta 1 (TGF-β1) in the patients with chronic allograft nephropathy (CAN), and further evaluate the correlation between them. Methods A total of 60 patients with chronic allograft nephropathy confirmed by renal biopsy were selected and divided into three groups according to the degree of interstitial fibrosis and tubular atrophy of the transplanted kidney: group C1 (renal cortex involvement 50%, n=20). 30 renal transplant recipients with normal renal function were enrolled for control group. The SWV of the renal were measured by virtual touch tissue quantification (VTQ) and the serum level of TGF-β1 were detected by enzyme linked immunosorbent assay (ELISA) in each group. Results Compared with control group, the SWV and serum TGF-β1 in case groups were significantly higher (P<0.05). SWV measured values: group C3 was the highest, group C2 was middle one and group C1 was the lowest (P<0.05). Statistically significant difference in serum TGF-β1 was observed among these three groups (P<0.05). The renal SWV and serum TGF-β1 had a significant positive correlation (r=0.631, P<0.05). Conclusions Both renal SWV and serum TGF-β1 increase as CAN progressed, which have high value in the diagnosis and treatment of CAN. Key words: Kidney transplantation; Kidney diseases; Ultrasonography, doppler, color; Transforming growth factor beta1

SDF‑1/CXCR4 induces epithelial‑mesenchymal transition through activation of the Wnt/β‑catenin signaling pathway in rat chronic allograft nephropathy.

Epithelial-mesenchymal transition (EMT) has been demonstrated to serve a crucial role in the progression of interstitial fibrosis, which is one of the principal pathological features of chronic allograft nephropathy (CAN). However, to the best of our knowledge, the mechanisms of EMT in CAN have not been investigated. In the present study, the effect of stromal cell-derived factor 1 (SDF-1) and the Wnt signaling pathway on the progression of EMT following kidney transplantation was investigated. The CAN model was established using Fisher 344 and Lewis rats, treated with low-dose cyclosporine with or without AMD3100. CAN was confirmed by the pathological alterations and chronic allograft damage index scoring, and EMT was confirmed by western blotting and reverse transcription-quantitative polymerase chain reaction. In the AMD3100 group, there were lower expression levels of α-SMA and higher expression levels of E-cadherin, which indicated that CAN and EMT were ameliorated by AMD3100. The kidney tissue was analyzed using an mRNA + long noncoding (lnc)RNA microarray. A total of 506 mRNAs and 404 lncRNAs were demonstrated to be significantly differentially expressed between the two groups, which revealed the involvement of SDF-1/CXC chemokine receptor 4 (CXCR4) and the Wnt pathway. SDF-1 was demonstrated to induce EMT in vitro through the upregulation of α-SMA, downregulation of E-cadherin and the wound healing assay, and in the rat renal tubular epithelial cells via the nuclear accumulation of β-catenin, which were all inhibited by either AMD3100 or DKK-1. CXXC finger protein 5 (CXXC5), a negative regulator of the Wnt pathway, was downregulated following treatment with SDF-1, which was inhibited by AMD3100 but not by DKK-1. Thus, CXXC5 may be a regulator downstream of SDF-1/CXCR4 in EMT. In conclusion, SDF-1/CXCR4 induces EMT of renal tubular epithelial cells with the involvement of the Wnt pathway, which may be a novel mechanism and therapeutic target in kidney allograft fibrosis of rats.

Immunoproteasome inhibition induces plasma cell apoptosis and preserves kidney allografts by activating the unfolded protein response and suppressing plasma cell survival factors

Chronic antibody-mediated rejection is the leading cause of allograft dysfunction and loss after kidney transplantation, and current immunosuppressive regimens fail to target the plasma cells that produce alloantibodies. We previously showed that treatment with the immunoproteasome inhibitor ONX 0914 prevented the expansion of plasma cells and prevented chronic allograft nephropathy and organ failure after kidney transplantation in rats, but the mechanism has remained elusive. In the current study, we confirmed a long-term reduction in alloantibody production and improvements in allograft histology in rats treated with ONX 0914 or with the broad-spectrum proteasome inhibitor bortezomib. Plasma cells from allotransplanted rats expressed immunoproteasomes at high levels. Immunoproteasome inhibition with ONX 0914 led to ubiquitin-conjugate accumulation, activation of the unfolded protein response, and induction of apoptosis in plasma cells. In addition, ONX 0914 suppressed the expression of adhesion molecules (VLA-4 and LFA-1), plasma cell survival factors (APRIL and IL-6), and IFN-γ-inducible chemokines in bone marrow, while the APRIL receptor BCMA, the IL-6 receptor, and the chemokine receptors CXCR4 and CXCR3 were down-regulated on plasma cells. Taken together, immunoproteasome inhibition blocked alloantibody production by inducing apoptosis of plasma cells through activating the unfolded protein response and suppressing plasma cell survival factors in the bone marrow.

The effect of maintaining high hemoglobin levels on long-term kidney function in kidney transplant recipients: a randomized controlled trial.

BackgroundPosttransplant anemia may be a major determinant of chronic allograft nephropathy. However, the impact of correcting anemia on graft function remains controversial.MethodsA 3-year follow-up of an open-label, multicenter, randomized controlled trial involving kidney transplantation recipients examined whether sustained maintenance of target hemoglobin (Hb) concentrations at a high level (12.5–13.5 g/dL, n = 64) with either darbepoetin alfa or epoetin beta pegol would slow the graft function decline rate as the primary efficacy endpoint, compared with maintenance of a low Hb concentration (10.5–11.5 g/dL, n = 63).ResultsThe mean blood pressures in the two groups were well controlled throughout the study. In the high Hb group, mean Hb concentrations increased to >12 g/dL at 3 months, reaching the target range at 18 months. At the end of this study (36 months), the mean Hb concentration was 12.8 ± 0.7 g/dL in the high Hb group and 11.5 ± 1.2 g/dL in the low Hb group. The decline rate of the estimated glomerular filtration (eGFR) rate was considerably greater in the low Hb group (ΔeGFR, −5.1 ± 9.5 mL/min/1.73 m2) than in the high Hb group (−1.0 ± 8.4 mL/min/1.73 m2) (P = 0.02). Of note, only a few high Hb patients developed cardiovascular events and returned to hemodialysis, but the low Hb patients did not.ConclusionThis prospective study suggests that correcting anemia to the target Hb level range (12.5–13.5 g/dL) slows renal function deterioration by >3 years in the chronic phase of allograft nephropathy.

Association between post-transplant serum uric acid levels and kidney transplantation outcomes.

BackgroundSerum uric acid (UA) level has been reported to be associated with chronic allograft nephropathy and graft failure in patients who undergo kidney transplantation (KT). However, the role of serum UA level in renal graft survival remains controversial.ObjectiveThis study aimed to investigate the effect of mean serum UA level during two different post-KT periods on long-term renal graft outcomes in a large population cohort in which living donor KT prevails.Material and methodsA retrospective cohort study was performed using KT data prospectively collected at a single institution. Patients (n = 2,993) were divided into low-, normal-, and high-UA groups according to the mean serum UA level within the first year (1-YR) and 1–5 years (5-YR) after transplantation.ResultsIn the 1-YR Cox proportional hazards analysis, the low- and high-UA groups had a significantly decreased and increased risk, respectively, for overall graft failure (OGF), death-censored graft failure (DCGF), and composite event (return to dialysis, retransplantation, death from graft dysfunction, and 40% decline in estimated glomerular filtration rate) compared with the normal-UA group. Similarly, in the 5-YR analysis, the low-UA group had a significantly reduced risk of DCGF compared with the normal-UA group, whereas the high-UA group had a significantly increased risk of all three graft outcomes. In a marginal structural model, hyperuricemia had a significant causal effect on worsening graft outcomes, with consideration of all confounding variables (OGF: hazard ratio [HR] 2.27, 95% confidence interval [CI] 1.33–3.78; DCGF: HR 2.38, 95% CI 1.09–4.9; composite event: HR 3.05, 95% CI 1.64–5.49).ConclusionsA low-to-normal serum UA level within the first year and 1–5 years after KT is an independent factor for better renal allograft outcomes in the long-term follow-up period rather than high serum UA level.

236. Pregnancy in renal transplant patients: renal function markers and maternal-fetal outcomes

Progressive proteinuria and glomerulosclerosis characterize chronic allograft nephropathy. Podocytes are fundamental cells for maintaining the functionality of glomerular filtration barrier. Failure to achieve this task due to reduced podocyte number and results in progressive glomerular dysfunction, causing proteinuria and glomerulosclerosis and ultimately leading to end-stage kidney disease. Assessment of podocyturia and its correlation with other renal parameters could help with the diagnosis and definition of prognosis of the glomerulopathies, thus contributing to risk reduction. To evaluate podocyturia and others renal parameters as functional markers in pregnant women with kidney grafts. In this cross-sectional and prospective study, 43 pregnant women with kidney grafts had their Mid-stream urine samples collected to determine proteinuria, including retinol-binding protein (enzyme immunoassay using monoclonalantibodies), albumin/creatinine ratio (immunoturbidimetry), protein/creatinine ratio (the alkaline picrate colorimetric method), and podocyturia (indirect immunofluorescence). 43 women who got pregnant after renal transplantation were included. Podocyturia was not significantly correlated with other renal function markers. A gradual increase was observed in the following parameters during pregnancy and puerperium: serum creatinine levels (P < 0.001), proteinuria (P < 0.001), urinary protein/creatinine ratio (P < 0.001), and albumin/creatinine ratio (P < 0.001). Elevated serum creatinine levels, urinary albumin/creatinine ratio, and retinol-binding protein levels in the third trimester were associated with prematurity (P < 0.001). Preeclampsia was the main cause of renal function decline at the end of pregnancy (65.0% of cases). Proteinuria, urinary protein/creatinine ratio, and retinol-binding protein levels were elevated in patients with preeclampsia. Proteinuria (or more specifically, urinary protein/creatinine ratio) and albumin/creatinine ratio has also used as a marker of CKD progression. We observed that urinary podocyte excretion occurs in pregnant women with kidney transplant. Using these markers to assess renal function during pregnancy may be clinically useful for early diagnosis and follow-up of glomerular injury, eventually preeclampsia. It may be also associated to its severity or activity.

Introduction of everolimus in kidney transplant recipients at a late posttransplant stage.

This minireview focuses on the current knowledge about the introduction of everolimus (EVL), a mammalian target of rapamycin inhibitor, with calcineurin inhibitor (CNI) elimination or minimization in kidney transplant recipients at a late posttransplant stage. Within, we have summarized two major clinical trials, ASCERTAIN and APOLLO, and seven other retrospective or nonrandomized studies. In the open-label multicenter ASCERTAIN study, the estimated glomerular filtration rate (eGFR) at 24 mo after conversion was not significantly different between three groups-EVL with CNI elimination, CNI minimization and continued CNI unchanged-at a mean of 5.4 years after transplantation. However, recipients with baseline creatinine clearance higher than 50 mL/min had a greater increase in measured GFR after CNI elimination. In the open-label multicenter APOLLO study, adjusted eGFR within the on-treatment population was significantly higher in the EVL continuation group than in the CNI continuation group at 12 mo after conversion at a mean of 7 years posttransplantation. Other studies on recipients without adverse events and already having satisfactory renal function showed favorable graft function by EVL late-induction with CNI elimination or reduction. These studies showed that chronic allograft nephropathy, CNI nephrotoxicity, CNI arteriolopathy, cancer and viral infection (especially cytomegalovirus infection) may be good indications for late conversion to EVL.

A Decade of Live Related Donor Kidney Transplant: Experience in a Tertiary Care Hospital of Bangladesh

Background: Kidney transplantation is the preferred treatment for end stage kidney disease (ESKD). Live related donor kidney transplant was started in BIRDEM General Hospital, Bangladesh, on 6th November 2004. The aim of this study was to share our last 10 years’ experience of live related donor kidney transplant.Methods: A questionnaire was formed and data were collected from the hospital records. We retrospectively evaluated patients’ clinical and laboratory findings.Results: A total of 111 live related donor kidney transplants were performed from 2004 to 2014. Male:female was 2.3:1. The mean age of the recipients was 37.45 ± 10.58 years. The causes of ESKD were chronic glomerulonephritis (CGN) (52, 46.9%), diabetes mellitus (DM) (31, 27.9%), hypertension (26, 23.4%), chronic pyelonephritis (1, 0.9%) and obstructive nephropathy (1, 0.9%). Pre-emptive transplantation was done in 4 (3.6%) patients. Patients on continuous ambulatory peritoneal dialysis and haemodialysis were 2 (1.8%) and 105 (94.6%) respectively. Most of the donors were siblings (55.9%). Majority (64.9%) had an uncomplicated recovery. The commonest complication during post-transplant hospital stay was infection (27.0%), mostly urinary tract infection (21.6%). Surgical failure was experienced in 1 (0.9%) and acute rejection was noted in 2 (1.8%) patients. Other complications were renal vein thrombosis (1, 0.9%), haemolytic uremic syndrome (1, 0.9%), acute tubular necrosis (1, 0.9%), peri-renal collection (1, 0.9%), pericardial effusion (1, 0.9%) and clot retention in urinary bladder (2, 1.8%). Mean post-transplant hospital stay was 12.39 ± 4.27 days. Mean duration from surgery to normalization of serum creatinine was 5.75 ± 4.15 days. During discharge, 71.2% patients had normal renal function (RF) with mean serum creatinine 1.03 ± 0.15 mg/dl and 26.1% patients had gradually improving RF with mean serum creatinine 2.01 ± 1.04 mg/dl. As induction, 61 (55%) patients received basiliximab and as maintenance therapy all patients received oral prednisolone, calcinurine inhibitor and mycophenolate. In the first year of transplant, 49.5% patients suffered from infections, of which urinary tract infection was the commonest (55.9%). Incidence of chronic allograft nephropathy in CGN, DM and hypertension patients were 25%, 19.4% and 23.1% respectively. Graft survival at 1 year, 3 years and 5 years was 94.06%, 85.88% and 77.27% respectively. Patient survival at 1 year, 3 years and 5 years was 98.1%, 88.24% and 84.09% respectively.Conclusions: Our results are comparable or in some aspects, even better in comparison to other centers of both developing and developed world. In a center of a developing country with limited facility and resource, these achievements are encouraging.Birdem Med J 2018; 8(3): 198-202

The value of diffusion tensor imaging in early diagnosis of chronic allograft nephropathy and monitoring graft fibrosis in rats

Objective To estimate the value of diffusion tensor imaging (DTI) in early diagnosis of chronic allograft nephropathy (CAN) and monitoring of graft fibrosis in rat models. Methods Thirty CAN rat models were established as experimental group by transplanting Fisher donor kidneys into Lewis recipients. Thirty Lewis rats that received Lewis kidneys served as control group. Serum creatinine (SCr) was monitored regularly every two weeks from 14 days after transplantation. Eight rats were randomly selected by random number table method and underwent DTI examination at 4, 12, 20 weeks after modeling. DTI scans were performed on the renal cortex and medulla to measure apparent diffusion coefficient (ADC) and fractional anisotropy (FA). From the remaining 22 rats in each group, 6 rats were randomly selected and underwent pathological analysis at 4, 12, 20 weeks after modeling. Histological changes in the kidney were evaluated by chronic allograft damage index (CADI) scores. The expression of alpha-smooth muscle actin (α-SMA) and Vimentin were quantitatively measured. The differences in creatinine, DTI parameters, CADI score, α-SMA, Vimentin expression level were analyzed by two independent samples t test in two groups, the differences among CADI score, α-SMA, Vimentin expression level of the experimental group were compared using ANOVA. The correlations among DTI parameters and CADI score, α-SMA and Vimentin expression level were analyzed using Pearson analysis. Results The creatinine in the experimental group increased continuously, and the creatinine in the control group showed no significant increase. The difference in creatinine between the two groups was statistically significant from 8th week after operation (P<0.01). There was no obvious difference in the size and signal intensity of transplanted kidneys in control group at different time points. Compared with the control group, the graft kidney in the experimental group at the 4 weeks demonstrated increased signal intensity with mild increased volume of kidney, and the boundaries between cortex and medulla were not clear. The cortex and medulla showed gradually increased signal intensity, heterogeneous signal distribution and marginal haziness over time. The ADC and FA value of renal cortex and medulla in experimental group were significantly lower than those in control group at 4, 12, 20 weeks (P<0.05). The ADC and FA values of the cortex and medulla gradually decreased in the experimental group over time, while the values of the parameters in the control group did not show a significant decrease. The ADC and FA values of the cortex and medulla were negatively correlated with the scores of CADI, and the expression level of α-SMA, Vimentin in the experimental group(r=-0.50 to-0.85, P<0.01). Conclusion DTI can be an effective technique for early diagnosis of CAN and monitoring of graft fibrosis process. Key words: Kidney transplantation; Chronic allograft nephropathy; Diffusion tensor imaging; Comparative study

Peripheral Blood Regulatory T Cells Are Diminished in Kidney-Transplant Patients with Chronic Allograft Nephropathy

Introduction Kidney transplantation (KT) remains the major life-saving treatment for patients with end-stage renal disease. Despite the improvements in immunosuppressive strategies in recent years, late kidney allograft loss is a critical clinical challenge for long-term graft survival Over the past two decades, immunosuppressive drugs have failed to produce substantial long-term graft survival. Kidney allograft recipients, especially those individuals receiving organs from deceased donors, frequently suffer from the slow deterioration of kidney function or chronic allograft nephropathy (CAN). However, defining CAN as an idiopathic and multifactorial entity has precluded more comprehensive studies. Abundant evidence from animal models, as well as limited evidence from humans, involves Tregs in kidney transplant tolerance, although the recognition of allo or self-antigens by Tregs is not clear. Objective Investigate the peripheral blood levels of CD4+CD25+FOXP3p3+ regulatory T cells (Tregs) in patients with chronic allograft nephropathy (CAN) one year after kidney transplantation and compare it with chronic disease undergo hemodialysis and healthy controls. Methods Twelve renal-transplant patients with an initial onset of CAN, 12 patients with chronic kidney disease (CKD) stage G5 on dialysis, and 13 healthy control individuals were evaluated regarding the proportion of Tregs in their peripheral blood via flow cytometry. Results The renal-transplant patients with CAN had a significantly lower proportion of Tregs than the hemodialysis-CKD patients and healthy controls (P<0.01). In contrast, the hemodialysis-CKD patients showed higher levels of Tregs than the renal-transplant patients with CAN and the healthy controls (P<0.01) Figure 1Conclusion The high level of peripheral blood Tregs in the hemodialysis-CKD patients suggests a chronic inflammatory state. However, the low frequency of Tregs in the peripheral blood from the renal-transplant patients with CAN suggests an unfavorable prognosis for allograft immune tolerance. In representation of the work team I would like to state, that there are no known conflicts of interest associated with these work and there has been no significant financial support for this work that could have influenced its outcome.

Early Conversion to mTOR Inhibitors Prevents Kidney Function Better Than Late Conversion

Introduction Mammalian target of rapamycin (mTOR) inhibitors are the major alternative immunosuppressive treatment to prevent the adverse effects of calcineurin inhibitor (CNI) based immunosuppressive regimen in kidney transplant (KT) recipients but the timing of conversion to mTOR inhibitors is still a controversial clinical decision. In our study, we aimed to compare the effects of early and late conversion to mTOR inhibitors in our KT recipient population to contribute the data of timing of mTOR inhibitor initiation in patients who were planned to use CNI-free immunosuppressive regimens. Materials and Methods 108 kidney recipients who were converted to mTOR inhibitor based immunosuppressive regimen from CNI-based immunosuppressive regimen were enrolled to our study according to their conversion time. KT recipients who were converted to mTOR inhibitor regimen in the first 12 months after KT were in the early conversion group (Group 1) and KT recipients who were converted to mTOR inhibitor regimen after the first year following KT were in the late conversion group (Group 2). The demographic, clinical and laboratory values of the patients were recorded and patients in both groups were followed-up for 24 months after conversion. Group 1 and Group 2 were compared according to their basic laboratory values, clinical situation and also graft kidney function. Results 32 patients who were converted to mTOR inhibitor based therapy in the first year after KT (Group 1) were compared to 76 patients who were converted to mTOR inhibitor therapy after the first year (Group 2). After 2 years of follow-up of all patients after conversion; serum creatinine levels and 24 hours proteinuria were significantly lower and creatinine clearance and serum high-density lipoprotein levels were significantly higher in the early conversion group compared to late conversion group. Other laboratory values showed no significant difference between two groups. No graft loss was obtained in the 2 years follow-up. Conclusion CNI-based immunosuppressive regimens after KT are still the first choice in the very early period but long-term results are controversial. Until recently, the major adverse effects of CNIs that result with conversion to mTOR inhibitors are malignancy, chronic allograft nephropathy, viral infections and metabolic disturbances. Current studies showed that, early conversion to mTOR inhibitor-based regimens are clearly associated with preserving short and long graft kidney function in the KT recipients. In our study, we determined the early conversion in the first year after KT showed better results compared to late conversion. We suggest that elective conversion to mTOR inhibitors in patients with stable kidney function rather than salvage conversion in patients with worsening kidney function would help maintaining graft kidney and patient survival.

Post Transplant De Novo Hepatitis C Virus infection in Renal Transplant Recipients

Objectives The clinical effects of hepatitis C virus infection acquired after transplant have not been thoroughly studied. We aimed to study hepatitis C virus-related morbidity and mortality with de novo hepatitis C virus infection after renal transplant. Materials and Methods Data from mortality files were retrospectively collected from January 2011 to January 2015. Patients were divided into 2 groups: hepatitis C virus positive (group A) and hepatitis C virus negative (group B). Results Eighty-one patients were included, with median duration of survival of 39 months after transplant. In group A (32 patients), 78.1% of patients were males, with mean age of 36.83 ± 9.15 years. The mean survival duration was better in group A than in group B (67.59 ± 67.1 vs 58.10 ± 59.6 mo; P = .58). Acute cellular rejection was 25% in group A versus 20.4% in group B, whereas chronic allograft nephropathy was 20.4% for group A versus 18.4% for group B. Hepatitis C virus-related death was observed in 7 patients (21.9%).Infection was the main cause of death, with 40.6% of patients in group A versus 53% of patients in group B. On multivariate analyses, better patient survival was associated with greater interval of acquiring HCV after transplant (P = .038) Conclusion HCV infection acquired after renal transplant is not associated with increased HCV related mortality, and prognosis is related to the time interval of acquiring infection after transplant.

Urinary C-X-C Motif Chemokines 13 is a Noninvasive Biomarker of Antibody-Mediated Renal Allograft Rejection

Background Since acute rejection remains one of the major complications which necessitate periodic surveillance, noninvasive diagnostic/prognostic methods are preferred by renal transplant recipients. Here we explored whether urinary C-X-C motif chemokines 13(CXCL13) could be apotential candidate to reflect ongoing immune processes within the renal graft. Methods We investigated urinary CXCL13 levels by a cross-sectional analysisof 146 renal allograft recipients and 40 healthy controls. Besides, a subset of patients (n = 57) were followed-up for kinetic monitoring of immune status. Results Urinary CXCL13/Cr was lower in normal transplants compared to those withacute tubular necrosis (ATN, P = 0.001), chronic allograft nephropathy (CAN, P = 0.01) andacute rejection (AR, P < 0.0001), which yielded a good diagnosis performance of urinary CXCL13 for AR (AUC = 0.818, P< 0.0001). Interestingly, urinary CXCL13 furtherdistinguished acute antibody mediated rejection (ABMR)from acute cellular rejection, with an AUC of 0.856. Besides,patients with steroid-resistant acute rejection had distinctly greater urinary CXCL13/Cr levels than patients with reversible acute rejection, P =0.001. Follow-up data revealed that urinary CXCL13/Cr varied in line with the occurrence of ABMR. Furthermore, elevated levels of urinary CXCL13/Cr within the first monthwas predictive of graft function at 3, 6 months, P=0.044 and 0.4. Conclusion This study demonstrated that monitoring of urinary CXCL13/Cr might be a valuable noninvasive approach for the detection of AR, especially ABMR. Additionally, high urinary CXCL13/Cr levels related to the poor response to steroid treatment and predicted a compromised graft function after AR. Key Words:C-X-C motif chemokines 13; kidney transplantation; rejection; urine Key Laboratory of Multiple Organ Transplantation, Ministry ofHealth.

Use of Electron Microscopy (EM)to Detect Transplant Glomerulopathy (TG) in Patients with Late-Indication Allograft Biopsy

Introduction The main causes of late graft loss are: death of patients with functioning graft and chronic allograft nephropathy, in which it stands out, to chronic rejection mediated by antibodies (cABMR). cABMR was defined during the Banff meeting in 2005 due to: Transplant Glomerulopathy (TG), Multilamination of the basal membrane of the tubular pericapillary (MLMBPCT), Transplant vasculopathy and interstitial fibrosis with tubular atrophy (IFTA), with deposit of C4d in PCT and the presence of Anti-HLA Antibodies specific donor (DSA). The presence of C4d deposition in the peritubular capillary (PTC) is a diagnostic marker of ABMR greater than 50% in acute graft rejection but not in its chronic or late ABMR phenotype, so its usefulness is currently questioned in the late phase, identifying them as C4d negative. The typical characterizes cABMR is TG recognized as a glomerulopathy that manifests a double contour of the glomerular capillary,. The cABMR with duplication or MLMBG, increase of the subendothelial space, interposition of mesangial cells, loss of fenestration in the endothelial cells, and MLMBPTC as the findings most significant effects linked to the interaction of antibodies in the glomerular endothelium. Objectives Detect morphological changes of TG by ME in patients with chronic allograft dysfunction who have late biopsies for clinical indication, whose previous histopathological evaluation was by Banff classification in MO and IHC for C4d. Materials and Methods We performed a retrospective observational study of a descriptive cohort, kidney transplant patients performed in the Nephrology and Transplant Service of the CPVS, Córdoba, Argentina who presented chronic allograft dysfunction with late biopsies for clinical indication performed in the period from July 2011 to August 2016.The MO and ME analysis was performed by two different pathologists.The indication for renal biopsy was performed according to the following criteria: increase in serum creatinine ≥0.3 mg / dl or more during the post-transplant evolution. Proteinuria evaluated by Pr/Cr ratio in spot urine ≥0.3 mg / dl.3. Patients with at least 6 months of kidney transplant.4. All samples of biopsies performed should have at least 4 glomeruli for the MO and ME analysis, respectively. Results Inflammation of the glomerular endothelium (GECS) in 21/22 95%.Podocyte deletion processes in 100% of patients, 22.7% severe and in the rest 76% mild to moderate. MLMBPTC, 68% were present in 63.6% 14/22 patients mild (<3 layers) and in only 5% was moderate (7 layers). ). MLMBG in 17/22 77.2%..Conclusion The use of EM in late kidney transplant biopsies by indication allowed detecting ultrastructural changes of transplant glomerulopathy of cABMR in a high % of patients with C4d negative w/wo DSA. Prospective studies should be necessary as protocol biopsies with earlier changes suggestive of TG with EM, and anticipate the clinically evident damage.

Biomarkers for individualized dosage adjustments in immunosuppressive therapy using calcineurin inhibitors after organ transplantation.

Calcineurin inhibitors (CNIs), such as cyclosporine A and tacrolimus, are widely used immunosuppressive agents for the prevention of post-transplantation rejection and have improved 1-year graft survival rates by up to 90%. However, CNIs can induce severe reactions, such as acute or chronic allograft nephropathy, hypertension, and neurotoxicity. Because CNIs have varied bioavailabilities, narrow therapeutic ranges, and individual propensities for toxic effects, therapeutic drug monitoring is necessary for all CNIs. Identifying the genetic polymorphisms in drug-metabolizing enzymes will help to determine personalized dosage regimens for CNIs, as CNIs are substrates for CYP3A5 and P-glycoprotein (P-gp, MDR1). CNIs are often concomitantly administered with voriconazole or proton pump inhibitors (PPIs), giving rise to drug interaction problems. Voriconazole and PPIs can increase the blood concentrations of CNIs, and both are primarily metabolized by CYP2C19. Thus, it is expected that interactions between CNIs and voriconazole or PPI would be affected by CYP2C19 and CYP3A5 polymorphisms. CNI-induced acute kidney injury (AKI) is a serious complication of transplantations. Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM-1) are noninvasive urinary biomarkers that are believed to be highly sensitive to CNI-induced AKI. In this article, we review the adverse events and pharmacokinetics of CNIs and the biomarkers related to CNIs, including CYP3A5, CYP2C19, MDR1, NGAL, and KIM-1. We hope that these data will help to identify the optimal biomarkers for monitoring CNI-based immunosuppressive therapy after organ transplantation.