Diagnosis Of Chronic Allograft Nephropathy Research Articles

THE RELATIONSHIP BETWEEN HIF-2 AND CHRONIC RENAL ALLOGRAFT NEPHROPATHY IN RENAL TRANSPLANTATION RECIPIENTS

Background: We aimed to investigate the role of HIF-2α on chronic allograft nephropathy, which is a consequence of chronic inflammation and fibrosis. Method: The study was conducted between November 2019 and January 2021, patients who had a kidney biopsy in our university in the last two years were included in the study. 15 patients with a diagnosis of chronic allograft nephropathy proven by biopsy, 15 patients with an eGFR below 60 ml/dk for other reasons as non-CAN group. Also, 15 patients with an eGFR above 60 ml/dk were included in the study as a control group. Serum HIF-2α levels were detected by a commercial kit using the quantitative sandwich enzyme immunoassay technique. Results: HIF-2α was higher in the CAN group compared to other groups. HIF-2α was significantly predictive in ROC analysis in identifying renal transplantation patients with CAN. The sensitivity and specificity of HIF-2α were 100% and 76% (cut off >0.2) with an area of under the ROC curve of 0.941 (95% CI 0. 850-1.000), p < 0.001). Conclusion: Serum HIF-2α may usefulness as potential simple biomarkers for detecting allograft dysfunction after kidney transplantation and it can be also a guide in determining these treatment strategies.

P1615IDENTIFICATION OF URINARY PROTEOMIC PROFILE OF PATIENTS WITH CHRONIC ALLOGRAFT NEPHROPATHY

Abstract Background and Aims Chronic allograft nephropathy (CAN) is a major complication that occurs post-transplantation. At present, the diagnosis of chronic allograft nephropathy (CAN) is based on renal biopsy. Therefore, there is an ultimate need to identify more specific and sensitive noninvasive methods for the early diagnosis of CAN. Recently, proteomic-based modalities have been developed to discover biomarkers of CAN. Method Urine samples from 75 participants were collected. Participants were divided into 3 groups: Group I: 25 patients with chronic allograft nephropathy, group II: 25transplanted patients with stable renal functions, and group III: 25 healthy control subjects matched for age and sex. Each group was divided into training set and test set. Specimens were purified with magnetic beads-based weak cation exchange chromatography and analyzed in a MALDI-TOF MS. Results A Genetic Algorithm (GA) was used to set up the classification models. Five peaks represented the proteomic profile that differentiates between the CAN patients and the control group with sensitivity of 100%, specificity of 100%, recognition capability of 100 % and cross-validation91.7 % and five peaks differentiate between the transplant patients with normal renal functions and the control groups with sensitivity of96.8 %, specificity of 95.5 %, recognition capability of 98 % and cross-validation of 100 %. Conclusion We identified a pattern for CAN and transplant patients with normal renal functions by proteomic profiling using MALDI-TOF-MS and magnetic beads.

Identification of urinary proteomic profile of patients with chronic allograft nephropathy

ABSTRACT Background and objectives Chronic allograft nephropathy (CAN) is a major complication that occurs post-transplantation. At present, the diagnosis of CAN is based on renal biopsy. Therefore, there is an ultimate need to identify more specific and sensitive noninvasive methods for the early diagnosis of CAN. Recently, proteomic-based modalities have been developed to discover biomarkers of CAN. Methods Urine samples from 75 participants were collected. Participants were divided into three groups: Group I: 25 patients with CAN, Group II: 25 transplanted patients with stable renal functions, and Group III: 25 healthy control subjects matched for age and sex. Each group was divided into training set and test set. Specimens were purified with magnetic beads-based weak cation exchange chromatography and analyzed using MALDI-TOF MS. Results A Genetic Algorithm (GA) was used to set up the classification models. Five peaks represented the proteomic profile that differentiates between the CAN patients and the control group with sensitivity of 100%, specificity of 100%, recognition capability of 100%, and cross-validation of 91.7% and five peaks differentiate between the transplant patients with normal renal functions and the control groups with sensitivity of 96.8%, specificity of 95.5%, recognition capability of 98%, and cross-validation of 100%. Interpretation and conclusions We identified a pattern for CAN and transplant patients with normal renal functions by proteomic profiling using MALDI-TOF-MS and magnetic beads.

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

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

TSI ultrasound elastography for the diagnosis of chronic allograft nephropathy in kidney transplanted patients.

PurposeTo answer the question whether the TSI (tissue strain imaging) sonoelastography technique can contribute to the diagnosis of chronic renal allograft damage.Material and methodsA prospective study of 112 patients between June 2010 and April 2011 was conducted to compare elastography data with biopsy results and laboratory parameters in order to determine whether any correlations exist. Elastography parameters were acquired with a high-end ultrasound system and analyzed using the semiquantitative strain ratio. For comparison, patients were divided into three groups based on biopsy findings (Banff classification): group A: biopsy not necessary; group B: Banff grade I; group C: Banff grades II and III. Correlations were assessed by means of correlation (Pearson) and regression analysis. Differences between ordinal groups were tested for statistical significance by the Mann-Whitney U test.ResultsMean patient age was 54.2 ± 15.01 years. Fifty-nine percent of the patients were male. The calculated TSI strain ratio of groups A and C differed significantly (p = 0.024). Groups B and C (p = 0.056) and groups A and B (p = 0.88) showed no significant difference. The TSI strain ratio did not correlate with glomerular filtration rate (r = 0.105) or creatinine (r = 0.092).ConclusionThe TSI sonoelastography technique can contribute to the differentiation of different stages of renal graft damage (according to Banff classification). However, significant results were not observed for all investigated features. The TSI technique should be further evaluated in future studies including larger numbers of patients.

Clinical assessment and determinants of chronic allograft nephropathy in maintenance renal transplant patients

Current knowledge about the natural history, treatment and physicians' perception of chronic allograft nephropathy (CAN) is limited. The present study evaluated the prevalence and determinants of CAN in renal transplant patients. Epidemiological, cross-sectional multi-centre study conducted in Spain. A total of 872 renal transplant recipients with a functioning graft and at least 2 years of post-transplant data on renal function were consecutively included. CAN diagnosis was recorded based on physician's clinical criteria and on laboratory criteria (serum creatinine ≥ 2 mg/dL and/or glomerular filtration rate ≤ 50 mL/min). The mean time from transplantation until the time of this study was 8.2 years. CAN was diagnosed in 35% of patients (n = 305) according to the physician's criteria (31% of whom with histological assessment) and in 55.5% (n = 482) according to laboratory objective criteria. An older donor age, lack of induction therapy, cyclosporine use, lower tacrolimus levels at 1 year, acute rejection, hypertension and worse initial renal function were associated with CAN development. Time from transplant to biopsy was greater in patients with anti-proteinuric treatment. Immunosuppression was modified in 46.9% of patients with CAN diagnosis [calcineurin inhibitor (CNI) reduction alone in 18.9% of cases; CNI reduction and mycophenolate modification in 17.8% and CNI reduction or withdrawal with introduction of proliferation signal inhibitors in 12.9%). After ~8 years from renal transplantation, 55.5% of patients presented CAN, which was considerably underestimated by physicians. An older donor age and less initial immunosuppression seemed to be related to CAN development.

Biomarkers for Early and Late Stage Chronic Allograft Nephropathy by Proteogenomic Profiling of Peripheral Blood

BackgroundDespite significant improvements in life expectancy of kidney transplant patients due to advances in surgery and immunosuppression, Chronic Allograft Nephropathy (CAN) remains a daunting problem. A complex network of cellular mechanisms in both graft and peripheral immune compartments complicates the non-invasive diagnosis of CAN, which still requires biopsy histology. This is compounded by non-immunological factors contributing to graft injury. There is a pressing need to identify and validate minimally invasive biomarkers for CAN to serve as early predictors of graft loss and as metrics for managing long-term immunosuppression.MethodsWe used DNA microarrays, tandem mass spectroscopy proteomics and bioinformatics to identify genomic and proteomic markers of mild and moderate/severe CAN in peripheral blood of two distinct cohorts (n = 77 total) of kidney transplant patients with biopsy-documented histology.FindingsGene expression profiles reveal over 2400 genes for mild CAN, and over 700 for moderate/severe CAN. A consensus analysis reveals 393 (mild) and 63 (moderate/severe) final candidates as CAN markers with predictive accuracy of 80% (mild) and 92% (moderate/severe). Proteomic profiles show over 500 candidates each, for both stages of CAN including 302 proteins unique to mild and 509 unique to moderate/severe CAN.ConclusionsThis study identifies several unique signatures of transcript and protein biomarkers with high predictive accuracies for mild and moderate/severe CAN, the most common cause of late allograft failure. These biomarkers are the necessary first step to a proteogenomic classification of CAN based on peripheral blood profiling and will be the targets of a prospective clinical validation study.

Switching to Sirolimus in Renal Transplant Recipients With Hepatitis C Virus: A Safe Option

The presence of hepatitis C virus (HCV) in renal transplant recipients is an independent risk factor for death and graft failure. Chronic allograft nephropathy (CAN) favored by the use of calcineurin inhibitors (CNI) is one of the main causes of graft loss, whereas sirolimus (SRL) has proven to maintain better graft function with lower rates of CAN. We developed a protocol to evaluate the safety of SRL in transplant recipients with respect to HCV. We studied 5 patients (3 men) of mean age 52 +/- 9.2 years with HCV who had not received antiviral treatment. The viral genotypes were 1b in 4 cases and 2a/2c in 1 case. Basic immunosuppression was mycophenolate mofetil (MMF) and corticosteroids in all patients, cyclosporine (CsA) in 4 cases, and tacrolimus (Tac) in 1 case. Before the switch, a renal biopsy was performed and viral replication and cryoglobulins determined. Biopsy provided a diagnosis of CAN in 1 case, CNI toxicity-associated CAN in 2 cases, CNI toxicity in 1 case, and no renal damage in the remaining case. We observed a nonsignificant decrease in the number (log) of viral copies with a stabilization of renal function but with a slight to moderate increase in proteinuria. The switch seemed to be safe with no increase in viral copies. Graft renal function remained stable with increased proteinuria that must be supervised, even though it did not reach statistical significance.

Synergistic effect of mycophenolate mofetil and angiotensin-converting enzyme inhibitor in patients with chronic allograft nephropathy

Experimental data and few clinical non-randomized studies have shown that inhibition of the renin-angiotensin system by angiotensin-converting enzyme (ACE) associated or not with the use of mycophenolate mofetil (MMF) could delay or even halt the progression of chronic allograft nephropathy (CAN). In this retrospective historical study, we investigated whether ACE inhibition (ACEI) associated or not with the use of MMF has the same effect in humans as in experimental studies and what factors are associated with a clinical response. A total of 160 transplant patients with biopsy-proven CAN were enrolled. Eighty-one of them were on ACE therapy (G1) and 80 on ACEI_free therapy (G2). Patients were further stratified for the use of MMF. G1 patients showed a marked decrease in proteinuria and stabilized serum creatinine with time. Five-year graft survival after CAN diagnosis was more frequent in G1 (86.9 vs 67.7%; P < 0.05). In patients on ACEI-free therapy, the use of MMF was associated with better graft survival. The use of ACEI therapy protected 79% of the patients against graft loss (OR = 0.079, 95%CI = 0.015-0.426; P = 0.003). ACEI and MMF or the use of MMF alone after CAN diagnosis conferred protection against graft loss. This finding is well correlated with experimental studies in which ACEI and MMF interrupt the progression of chronic allograft dysfunction and injury. The use of ACEI alone or in combination with MMF significantly reduced proteinuria and stabilized serum creatinine, consequently improving renal allograft survival.

Are the current chronic allograft nephropathy grading systems sufficient to predict renal allograft survival?

A major problem in renal transplantation is identifying a grading system that can predict long-term graft survival. The present study determined the extent to which the two existing grading systems (Banff 97 and chronic allograft damage index, CADI) correlate with each other and with graft loss. A total of 161 transplant patient biopsies with chronic allograft nephropathy (CAN) were studied. The samples were coded and evaluated blindly by two pathologists using the two grading systems. Logistic regression analyses were used to evaluate the best predictor index for renal allograft loss. Patients with higher Banff 97 and CADI scores had higher rates of graft loss. Moreover, these measures also correlated with worse renal function and higher proteinuria levels at the time of CAN diagnosis. Logistic regression analyses showed that the use of angiotensin-converting enzyme inhibitor (ACEI), hepatitis C virus (HCV), tubular atrophy, and the use of mycophenolate mofetil (MMF) were associated with graft loss in the CADI, while the use of ACEI, HCV, moderate interstitial fibrosis and tubular atrophy and the use of MMF were associated in the Banff 97 index. Although Banff 97 and CADI analyze different parameters in different renal compartments, only some isolated parameters correlated with graft loss. This suggests that we need to review the CAN grading systems in order to devise a system that includes all parameters able to predict long-term graft survival, including chronic glomerulopathy, glomerular sclerosis, vascular changes, and severity of chronic interstitial fibrosis and tubular atrophy.

Rapamycin Inhibits PAI-1 Expression and Reduces Interstitial Fibrosis and Glomerulosclerosis in Chronic Allograft Nephropathy

Chronic allograft nephropathy (CAN) is characterized by deposition of extracellular matrix (ECM) in all renal compartments. PAI-1 seems to play a pivotal role in ECM turnover in CAN. Rapamycin has been shown to improve long-term graft survival in patients with CAN. The aim of the study was to evaluate the molecular mechanisms underlying the beneficial effects of rapamycin on CAN progression at glomerular and tubulointerstitial level. After a biopsy-proven CAN diagnosis (T0), 18 patients on calcineurin inhibitors (CNI) were randomly assigned in a 2:1 ratio to continue CNI (6 patients) or to receive rapamycin (RAPA; 12 patients). After 2 years of treatment (T24), all patients underwent a second renal biopsy. Morphometric analysis was conducted at T0 and at T24. PAI-1 expression was evaluated at T0 and T24 by immunohistochemistry. We evaluated the effect of rapamycin on PAI-1 gene expression in cultured proximal tubular cells incubated with CD40L or thrombin, two potential CAN pathogenic mediators. The RAPA group showed a significant regression of glomerulosclerotic lesions and only a 26% increase in interstitial fibrosis after 2 years compared to baseline, whereas the CNI group showed progression of glomerulosclerosis and 112% increase in fibrosis. Glomerular and tubulointerstitial PAI-1 expression was reduced compared to the baseline in the RAPA group, while they were unchanged in the CNI group. In vitro data showed that rapamycin significantly reduced PAI-1 gene expression induced by both CD40L and thrombin in proximal tubular epithelial cells. These data suggest that rapamycin may modulate ECM deposition in CAN reducing PAI-1 expression.

C4d-Positive Chronic Rejection: A Frequent Entity With a Poor Outcome

Chronic rejection (CR) is an important cause of kidney graft loss. Some studies have suggested the role of antibodies mediating chronic graft dysfunction. In this context, C4d identification is an important tool to evaluate antibody-mediated rejection. This is a retrospective study that analyzed 80 patients with histological diagnosis of chronic allograft nephropathy (CAN) according Banff 97 and no evidence of transplant glomerulopathy. These patients had renal biopsies available for C4d immunoperoxidase staining at the time of diagnosis. Cases were reclassified by the presence of C4d in peritubular capillaries. C4d was negative in 30 cases (37.5%) and positive in 50 (62.5%). C4d+ group had more female and highly sensitized patients (PRA) at transplant. All variables were similar between C4d- and C4d+ cases at diagnosis time, but more C4d+ patients presented proteinuria (>0.3 g/L). Patients were submitted to various immunosuppression regimens after the CAN diagnosis. Four years after the diagnosis, death-censored graft survival was 87% for C4d- and 50% for C4d+ (P=0.002). In the multivariate Cox regression analysis, C4d+, PRA>10%, and vascular intimal proliferation were the variables that present higher relative risk for graft loss. These data indicate that C4d positive chronic rejection is very common, associated with proteinuria, and has a poor outcome. A larger study is warranted to identify which immunosuppressive regimen may modify the poor course of this entity.

Quantification of Interstitial Fibrosis by Image Analysis on Routine Renal Biopsy 1 Year After Transplantation in Patients Managed by C 2 Monitoring of Cyclosporine Microemulsion

Background Renal interstitial fibrosis (IF), the main histopathologic feature of chronic allograft nephropathy (CAN), may be an important surrogate endpoint for patient follow-up. IF is currently assessed by semiquantitative analysis, but automatic color image analysis may be a more reliable, reproducible method to evaluate IF. We performed a retrospective analysis to calculate IF on routine renal biopsies 1 year after transplantation. Methods Data were obtained from MO2ART, a prospective multicenter trial in which the cyclosporine microemulsion dose was adjusted based on C 2 levels. We included 26 patients in whom routine renal biopsy at 1 year was available from two centers. For each biopsy, a section was analyzed by a program of color segmentation image that automatically extracted green-colored areas characteristic of IF. Results were expressed as percent IF and grade namely grade I, <25%; grade II, 25% to 50%; and grade III, >50%. The results were compared according to clinical and biological data. Results The 26 patients had a mean IF score of 0.35 ± 0.04. We observed 34.6% CAN grade I; 46.1%, grade II; and 19.2%, grade III. Serum creatinine at 3 years was greater in the higher grade of automated IF by repeated ANOVA. Conclusion Automatic quantification of IF on routine biopsy at 1 year after transplantation was predictive of renal outcome. This technique may provide an interesting tool for the early diagnosis of CAN after renal transplantation.

Conversion From Cyclosporine to Tacrolimus for Chronic Allograft Nephropathy

We investigate the effect of conversion from a cyclosporine (CsA) based-regimen to a tacrolimus (FK506)-based regimen with respect to graft renal function induced by chronic allograft nephropathy (CAN). Thirty-one patients with a histological diagnosis of CAN were included after other causes of chronic graft dysfunction had been excluded. Conversion to FK506 was undertaken at an initial dose of 0.15 mg/kg/d, which was subsequently adjusted to maintain FK506 whole blood trough levels between 5 and 10 μg/L. The rate of decline of renal function before and after the FK506 conversion was represented by regression lines (slope) of the reciprocal of serum creatinine versus time. To evaluate the effect of conversion on allograft function, we gathered data on serum lipids, blood glucose, proteinuria, and hypertension. When postconversion slopes were compared to preconversion slopes for each patient, 20 patients (64.5%) showed positive regression lines and four patients (12.9%), less negative. Seven patients (22.6%) displayed an increased rate of decline in renal function with regression lines becoming more negative. FK506 was associated with a significant decrease in lipid levels, proteinuria, and hypertension. No patient returned to dialysis at the end of the 36-month follow-up. Conversion from a CsA-based regimen to a tacrolimus-based regimen was an effective alterative for salvage of patients with abnormal graft renal function induced by CAN.

Real-Time Contrast-Enhanced Sonography of Renal Transplant Recipients Predicts Chronic Allograft Nephropathy

Real-time contrast-enhanced sonography (RT-CES) can assess microvascular tissue perfusion using gas-filled microbubbles. The study was performed to evaluate the feasibility of RT-CES in detecting chronic allograft nephropathy (CAN) in comparison to color Doppler ultrasonography (CDUS). A total of 26 consecutive renal transplant recipients were prospectively studied using RT-CES and conventional CDUS. Transplant tissue perfusion imaging was performed by low-power imaging during i.v. administration of the sonocontrast Optison. Renal tissue perfusion was assessed quantitatively using flash replenishment kinetics of microbubbles to estimate renal blood flow A *beta (A = peak signal intensity, beta= slope of signal intensity rise). In contrast to conventional CDUS resistance and pulsatility indices, renal blood flow estimated by CES was highly significant related to S-creatinine (r =-0.62, p = 0.0004). Determination of renal blood flow by CES reached a higher sensitivity (91% vs. 82%, p < 0.05), specificity (82% vs. 64%, p < 0.05) and accuracy (85% vs. 73%, p < 0.05) for the diagnosis of CAN as compared to conventional CDUS resistance indices. Perfusion parameters derived from RT-CES significantly improve the early detection of CAN compared to conventional CDUS. RT-CES using low-power real-time perfusion imaging is a feasible method to evaluate microvascular perfusion in renal allograft recipients.

Study of mRNA Growth Factors in Urinary Cells of Kidney Transplant Recipients as Predictors of Chronic Allograft Nephropathy

Chronic allograft nephropathy (CAN) is responsible for a significant proportion of graft loss. Current diagnostic methods for CAN are inadequate, and noninvasive assays for detecting allograft dysfunction/rejection and predicting long-term outcomes are a priority in transplantation. Urine samples were collected from 48 kidney transplant recipients (KTR): 18 recipients with stable graft function (creatinine levels<2.0 mg/dL) and proteinuria of less than 500 mg/24 hr (Group 1); 18 recipients with stable graft function and proteinuria of greater than 500 mg/24 hr (Group 2); and 12 recipients with biopsy confirmed CAN. Urinary cell levels of transforming growth factor-beta1 (TGF-beta1) mRNA or epidermal growth factor (EGF) mRNA were measured using real-time quantitative PCR assay, and levels were correlated with renal allograft status. The integrity of RNA isolated from urine sediments was also assessed using the Agilent 2100 Bioanalyzer. Urinary cell TGF-beta1 mRNA levels were higher in the CAN group compared to Group 1 (P<0.0001) or Group 2 (P<0.0001). Urinary cell EGF mRNA levels were higher in Group 1 compared to Group 2 (P<0.0001) or the CAN group (P<0.0001). There were no significant differences in the urinary cell levels of EGF mRNA between patients with greater than 500 mg/24 hr proteinuria (Group 2) and the CAN group (P=0.75). These results demonstrate that urinary cell TGF-beta1 mRNA levels distinguish CAN patients from long-term transplant patients with stable renal function and varied levels of proteinuria. Urinary cells may be a good resource for the noninvasive diagnosis of CAN.

Reproducibility of the Banff classification in subclinical kidney transplant rejection

The Banff classification for kidney allograft pathology has proved to be reproducible, but its inter and intraobserver agreement can vary substantially among centres. The aim of this study was to evaluate Banff reproducibility of surveillance renal allograft biopsies among renal pathologists from different transplant centres. This study included 32 renal transplant patients with stable graft function. Biopsies were performed 2 and 12 months post-transplant. Histology was interpreted according to the Banff schema by three renal pathologists, and inter and intraobserver agreement were measured. The best reproducibility was obtained for the presence or absence of acute rejection (AR), with kappa values ranging from moderate (kappa = 0.47; p = 0.006) to good (kappa = 0.72; p = 0.0001). However, the agreement for 'suspicious for AR' category was poor between all observers. For scoring and grading interstitial inflammation and intimal arteritis the agreement were poor and moderate, respectively. Reproducibility for the presence or absence of chronic allograft nephropathy (CAN) was heterogeneous, ranging from poor (kappa = 0.13; p = NS) to moderate (kappa = 0.56; p = 0.007). Scoring chronic changes such as fibrous intimal thickening gave a reasonable interobserver agreement. Intraobserver reproducibility was good for presence or absence of AR, but was poor for the diagnosis of CAN. In conclusion, histologic analysis of stable renal allografts based on Banff criteria showed a good agreement for the diagnosis of AR and a reasonable kappa for CAN, but reproducibility for scoring and grading showed a substantial interobserver variation.

Tubular and Glomerular Proteinuria in Diagnosing Chronic Allograft Nephropathy With Relevance to the Degree of Urinary Albumin Excretion

The diagnosis of chronic allograft nephropathy (CAN) is based on pathological examination according to Banff 97 schema. The aim of the study was to evaluate the usefulness of tubular and glomerular proteinuria for noninvasive recognition of CAN. One hundred and thirty renal allograft recipients (at least 90 days after transplantation) who had undergone diagnostic allograft biopsy were included in the study. Beta2-microglobulin, alpha1-microglobulin, albumin, immunoglobulin G, total protein, and creatinine concentrations were obtained from the second morning urine specimen. Raw data and values calculated per 1 g of creatinine excreted in urine along with time after transplantation, serum creatinine, and its change over a period of 2 months prior to biopsy were taken for analysis. Urine proteins were measured using a nephelometric method. Statistical calculations were performed using MANOVA and stepwise discriminant analysis (SDA). Statistical diagnosis and staging of CAN matched the pathological method in 68% of a preliminary SDA. Therefore patients were divided into normoalbuminuric, microalbuminuric, and macroalbuminuric groups. There was no significant differences between protein excretion, except alpha1-microglobulinuria (CAN 0 vs 2, P = .018; CAN 1 vs 2, P = .041), beta2-microglobulinuria (CAN 0 vs 2, P = .026; CAN 1 vs 2, P = .0033), and total proteinuria (CAN 0 vs 2, P = .042) in the normoalbuminuric group. Nevertheless, diagnoses obtained using SDA were 89%, 91%, and 92% identical to the results of pathological examinations, for normoalbuminuric, microalbuminuric, and macroalbuminuric groups, respectively. In conclusion, tubular and glomerular proteinuria measurements may be useful for a noninvasive CAN diagnosis and staging only with regard to degree of urinary albumin excretion.

Weight Gain After Living-Related Renal Transplantation Affects Long-Term Graft Function

Weight gain is a common problem in renal transplant recipients. This study investigated whether weight gain after living-related renal transplantation affects long-term graft function. The cohort included 93 patients (28 females, 65 males of mean age, 33.78 ± 9.78 years who were recipients of kidneys from living-related donors. The data set related risk factors to occurrence of chronic allograft nephropathy (CAN): namely, number of HLA mismatches, PRA levels, delayed graft function, acute rejection, suboptimal immunosuppression, hypertension, hyperlipidemia, and size mismatch. Patients with a 10% increase in body mass index sustained throughout at least 2 years posttransplantation were categorized as group 1 (abnormal weight gain; n = 65) and the others were categorized as group 2 (no or normal weight gain; n = 28). Chronic allograft nephropathy was more frequent among group 1 ( P < .03). The mean times to CAN diagnosis in groups 1 and 2 were 1053.41 ± 461.86 days and 1128.57 ± 416.09 days, respectively ( P > .05). Of all the risk factors for CAN, occurrence of acute rejection was the most important (OR = 5.39, 95% CI: 2.07 to 14.03, P < .001). When this factor was excluded, weight gain emerged as the most important risk factor (OR = 3.04, 95% CI: 1.01 to 9.69, P < .04). There were no significant differences between the groups with respect to the frequencies of immunologic and nonimmunologic risk factors ( P > .05 for all). The results suggest that excessive weight gain after living-related renal transplantation may be an additional risk factor for development of CAN. Patients should pay attention to diet and control weight gain after transplantation.