Living donor kidney transplants: a biopsy study 1 year after transplantation, compared with baseline changes and correlation to kidney function at 1 and 3 years

Human kidney graft survival correlates with structural parameters in baseline biopsies: a quantitative observational cohort study with more than 14 years' follow-up

This prospective cohort study evaluates associations between structural and ultrastructural parameters in baseline biopsies from human kidney transplants and long-term graft survival after more than 14 years' follow-up. Baseline kidney graft biopsies were obtained prospectively from 54 consecutive patients receiving a kidney transplant at a single institution. Quantitative measurements were performed on the baseline biopsies by computer-assisted light microscopy and electron microscopy. Stereology-based techniques estimated the fraction of interstitial tissue, the volume of glomeruli, mesangial fraction, and basement membrane thickness of glomerular capillaries. The fraction of occluded glomeruli and scores according to the Banff classification were achieved. Kidney graft survival was analyzed by Kaplan-Meier estimates and Cox regression. Association to long-term kidney function was also analyzed. The long-term surviving kidney transplants were characterized at implantation by less arteriolar hyaline thickening (P < 0.001) and less interstitial fibrosis (P = 0.001), as well as a lower fraction of occluded glomeruli (P = 0.004) and lower glomerular volume (P = 0.03). At the latest follow-up, eGFR was decreased by 12 ml/min/1.73 m² per unit increase in the score for arteriolar hyalinosis at implantation (P = 0.02), and eGFR was decreased by 19 ml/min/1.73 m² per 10⁶ μm³ increase in glomerular volume at baseline (P = 0.03). The unbiased Cavalieri estimate of glomerular volume and the ultrastructural parameters are the first to be evaluated in a cohort study with prospective follow-up for more than 14 years. The study shows that baseline biopsies from human kidney grafts contain extraordinary long-term prognostic information, and it highlights the importance of these intrinsic graft factors.

Novel histopathologic predictors for renal outcomes in crescentic glomerulonephritis

Introduction

Crescentic glomerulonephritis (CrGN) is a histologic feature of severe glomerular injury, clinically characterized by a rapid decline of renal function when not treated in a timely fashion. Factors associated with CrGN prognosis have not been thoroughly investigated. This study investigated the prognostic predictors of renal outcomes associated with CrGN, such as the histopathologic classification of anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis, arteriosclerosis, and tertiary lymphoid organ (TLO) formation.

Methods

A total of 114 patients diagnosed with CrGN between 2010 and 2018 at two university-based hospitals has been retrospectively analyzed. Relationships between potential predictors and renal outcomes were analyzed using Cox proportional hazards model and linear regression analysis.

Results

The mean age was 61.0 ± 15.3 years, and 49.1% were male. Among them, 92 (80.7%) and 11 (9.6%) patients were positive for ANCA and for anti-glomerular basement membrane antibody, respectively. During the median follow-up of 458.0 days, 55 patients (48.2%) had advanced to end-stage renal disease (ESRD). Cox proportional hazards analysis revealed that patients under the mixed and sclerotic classes had worse renal survival compared to those in the focal class (mixed: hazard ratio [HR], 3.74; 95% confidence interval [CI], 1.18 to 11.82; P = 0.025; sclerotic: HR, 4.84; 95% CI, 1.44 to 16.32; P = 0.011). Severe arteriosclerosis was also associated with poor renal survival (HR, 2.44; 95% CI, 1.04 to 5.77; P = 0.042). TLOs were observed in 41 patients (36.0%). Moreover, TLO formation was also a prognostic factor for ESRD (HR, 1.82; 95% CI, 1.03 to 3.21; P = 0.040). In the multivariate linear regression analysis, age and sclerotic class were independent predictors for the change in estimated glomerular filtration rate during 1 year after biopsy.

Conclusions

Specific histopathologic findings, histopathologic classification, severity of arteriosclerosis, and TLO formation provide helpful information in predicting renal outcomes associated with CrGN.

R, R. S. Role of Diffusion Tensor Imaging in Functional Assessment of Transplant Kidneys at 3-Tesla MRI

Objectives The main purpose of this article is to measure the fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of cortex and medulla of renal allograft using 3-Tesla diffusion tensor imaging (DTI) in renal transplant patients with normal and graft dysfunction and to assess the correlation between diffusion tensor parameters (ADC and FA) and the estimated glomerular filtration rate (eGFR) value.

Materials and Methods Fifty renal transplant recipients who received either living or cadaveric renal allografts were included in the study. Blood samples for serum creatinine and eGFR value were taken on the same day prior to the magnetic resonance study and the patients were assigned to three groups (A, B, C) according to allograft function (eGFR levels). The mean ADC and FA values of the cortex/medulla in upper, mid, and lower poles were calculated from the DTI sequence. Statistical analysis was performed using paired sample Student’s t-test and one-way analysis of variance test.

Results The mean ADC values of the cortex were higher than the medulla that was statistically significant. However, the mean FA values were significantly higher in the medulla than the cortex. Mean ADCs and FA of the renal cortex and medulla were significantly higher in group A patients with normal renal function than in group B and C with poor renal functions. The corticomedullary difference in the FA values was more in group A. However, this difference was lower in group B and more so in group C.

Conclusion ADC and FA values in the renal cortex and medulla exhibit a good correlation with allograft function and were significantly lower in transplants with dysfunction than those with good function. FA values appear to be more sensitive than eGFR and ADC for detection of early pathological changes in the graft dysfunction.

Zero-Time Renal Transplant Biopsies: A Comprehensive Review

Zero-time kidney biopsies, obtained at time of transplantation, are performed in many transplant centers worldwide. Decisions on kidney discard, kidney allocation, and choice of peritransplant and posttransplant treatment are sometimes based on the histological information obtained from these biopsies. This comprehensive review evaluates the practical considerations of performing zero-time biopsies, the predictive performance of zero-time histology and composite histological scores, and the clinical utility of these biopsies. The predictive performance of individual histological lesions and of composite scores for posttransplant outcome is at best moderate. No single histological lesion or composite score is sufficiently robust to be included in algorithms for kidney discard. Dual kidney transplantation has been based on histological assessment of zero-time biopsies and improves outcome in individual patients, but the waitlist effects of this strategy remain obscure. Zero-time biopsies are valuable for clinical and translational research purposes, providing insight in risk factors for posttransplant events, and as baseline for comparison with posttransplant histology. The molecular phenotype of zero-time biopsies yields novel therapeutic targets for improvement of donor selection, peritransplant management and kidney preservation. It remains however highly unclear whether the molecular expression variation in zero-time biopsies could become a better predictor for posttransplant outcome than donor/recipient baseline demographic factors.

Renal Interstitial Fibrosis: An Imperfect Predictor of Kidney Disease Progression in Some Patient Cohorts

BACKGROUND

The extent of interstitial fibrosis on kidney biopsy is regarded as a prognostic indicator and guide to treatment. Patients with extensive fibrosis are assigned to supportive treatments with the expectation that they have advanced beyond the point at which immunosuppressive or other disease-modifying therapies would be of benefit. Our study highlights some of the limitations of using interstitial fibrosis to predict who will develop end-stage renal disease (ESRD).

METHODS

Analysis of 434 consecutive renal biopsies performed between 2001 and 2012 at a single center. We assessed the influence of various clinical factors along with fibrosis as predictors of ESRD and dialysis-free survival in various patient groups.

RESULTS

Interstitial fibrosis performed well overall as a predictor of progression to dialysis. On average, patients with >50% fibrosis progressed more rapidly than those with either 25-49 or 0-24% fibrosis with a median time to dialysis of 1.2, 6.5 and >10 years, respectively. In contrast, interstitial fibrosis was of less value as a predictor of disease progression in a subset of cases that included patients over the age of 70 and those with diabetic nephropathy on biopsy. Surprisingly, 13.9% of patients with normal renal function had 25-49% fibrosis and 5% had more than 50% fibrosis on biopsy, and 5 years after undergoing biopsy 21% of patients with >50% fibrosis still remained dialysis free.

CONCLUSION

Renal fibrosis is an imperfect prognostic indicator for the development of ESRD and caution should be exercised in applying it too rigidly, especially in elderly or diabetic patients.

Renal Graft Fibrosis and Inflammation Quantification by an Automated Fourier-Transform Infrared Imaging Technique

Renal interstitial fibrosis and interstitial active inflammation are the main histologic features of renal allograft biopsy specimens. Fibrosis is currently assessed by semiquantitative subjective analysis, and color image analysis has been developed to improve the reliability and repeatability of this evaluation. However, these techniques fail to distinguish fibrosis from constitutive collagen or active inflammation. We developed an automatic, reproducible Fourier-transform infrared (FTIR) imaging-based technique for simultaneous quantification of fibrosis and inflammation in renal allograft biopsy specimens. We generated and validated a classification model using 49 renal biopsy specimens and subsequently tested the robustness of this classification algorithm on 166 renal grafts. Finally, we explored the clinical relevance of fibrosis quantification using FTIR imaging by comparing results with renal function at 3 months after transplantation (M3) and the variation of renal function between M3 and M12. We showed excellent robustness for fibrosis and inflammation classification, with >90% of renal biopsy specimens adequately classified by FTIR imaging. Finally, fibrosis quantification by FTIR imaging correlated with renal function at M3, and the variation in fibrosis between M3 and M12 correlated well with the variation in renal function over the same period. This study shows that FTIR-based analysis of renal graft biopsy specimens is a reproducible and reliable label-free technique for quantifying fibrosis and active inflammation. This technique seems to be more relevant than digital image analysis and promising for both research studies and routine clinical practice.

Donor Kidney Evaluation

In patients with end-stage renal disease, kidney transplantation is the best means to extend survival and offer a better quality of life. The current shortage of organs available for transplantation has led to an effort to expand the kidney donor pool, including the use of nonideal donor kidneys. Assessment of the quality of the donated kidney is essential, and would facilitate the decision to transplant a potential organ or discard it. Multiple clinical and histologic parameters have been examined to evaluate the donor kidney and relate the findings to the graft outcome, but clear-cut criteria are yet to be defined.

The cutting (w)edge--comparative evaluation of renal baseline biopsies obtained by two different methods

BACKGROUND

The assessment of donor-derived damage of transplanted kidneys might be instrumental for estimating donor organ quality and for predicting short- and long-term organ outcome. In the present study, we report a new standardized method for obtaining pre-transplant kidney biopsy specimens. Instead of taking wedge biopsies (WBs), a skin punch biopsy (PB) tool was utilized to obtain standardized biopsy samples that also represented deeper cortical zones.

METHODS

We compared 147 PB specimens and 114 WBs with respect to the number of glomeruli and arterial vessels they contained. The performance of the two biopsy methods in detecting glomerular damage, interstitial fibrosis/tubular atrophy (IF/TA) and arteriosclerosis was determined by evaluation of subsequent transplant core biopsies of the patients. Statistical comparison employed Kruskal-Wallis and kappa (κ) tests.

RESULTS

Significantly more PB samples (89%) than WBs (66%) were diagnostically adequate according to the Banff criteria. Despite a higher number of glomeruli in WBs (34.6 versus 21.7 in punch biopsies), arteries were present in only 68% of WBs but could be found in 93% of punch biopsies. The comparison of findings in pre-transplant biopsies with lesions in corresponding post-transplant core biopsies revealed a superior diagnostic concordance for IF/TA and arteriosclerosis for punch biopsies than for WBs, reaching kappa values of 0.823 versus 0.729 and 0.661 versus 0.516, respectively.

CONCLUSION

The use of skin PB tools for obtaining baseline biopsies from transplanted kidneys is a safe and effective method for assessment of donor-derived damage of the organ.

The prognostic value of frozen section preimplantation graft biopsy in the outcome of renal transplantation

INTRODUCTION

Preimplantation biopsy provides a window on the state of the renal allograft. In this study, the prognostic value of frozen section preimplantation graft biopsy was estimated and compared to regularly processed formalin-fixed biopsy.

MATERIALS AND METHODS

Seventy-four renal allograft recipients were studied. The degree of glomerulosclerosis, acute tubular necrosis, interstitial fibrosis, arteriosclerosis, and arteriolosclerosis was rapidly estimated in frozen sections and correlated to the renal function in the immediate posttransplantation period and 3 months thereafter. The histological changes were also examined in paraffin-embedded sections.

RESULTS

The histological changes observed in rapidly processed frozen sections were comparable to those observed on regularly processed sections and their differences did not reach statistical significance. Glomerulosclerosis and arteriolosclerosis were underestimated, whereas acute tubular necrosis and interstitial fibrosis were overestimated, in the frozen sections compared to permanent ones, but those differences were not statistically significant. Immediate graft function was observed in 45 patients (61%). Delayed graft function was more frequently observed among recipients with donor age above 60 years (57% vs. 32%). Serum creatinine 3 months after transplantation was above 2 mg/dL in 33 recipients (44.5%) and was positively correlated to the degree of tubular necrosis (p = 0.04) and donor age (p = 0.03). Donor age was correlated to the degree of arteriolosclerosis (p < 0.01).

CONCLUSIONS

Frozen section preimplantation biopsy gives reliable information for the situation of the graft that is related to the outcome of renal transplantation.

[Screening biopsies in kidney transplantation: from subclinical acute rejection to chronic allograft lesions]

Kidney biopsies for screening purposes have the advantage of revealing the early appearance of lesions having a poor prognosis before kidney function is altered. Early screening of subclinical rejections allows preventive treatment of kidney transplantation in patients taking cyclosporine or azathioprine, thus improving their renal function and reducing the incidence of chronic histological lesions. However, this benefit has yet to be demonstrated in patients taking tacrolimus or mycophenolic acid. As for interstitial fibrosis lesions and tubular atrophy, biopsies can screen subclinical immunological lesions or those related to nephrotoxicity of anticalcineurins, which have a negative prognostic value in terms of graft survival. In addition, detection of these lesions could be a very useful criterion of efficacy in clinical studies. Moreover, they could help decide on modifying immunosuppressor treatment and evaluate the therapeutic strategies in patients at risk for humoral rejection. Finally, given the cost of biopsies and the inconvenience for the patient, the question of the timing and the number of screening biopsies is crucial. However, interventional studies evaluating notably immunosuppressor treatment modifications based on histological data are necessary to justify the daily use of screening biopsies.

Quantification of interstitial fibrosis by image analysis on routine renal biopsy in patients receiving cyclosporine

BACKGROUND

Renal interstitial fibrosis (IF) is the main histopathological feature of chronic allograft injury. IF is currently assessed by semiquantitative analysis, but automatic color image analysis may be more reliable and reproducible. We performed a retrospective analysis to calculate IF on routine renal biopsies performed at 1 year posttransplant.

METHODS

Data were obtained from MO2ART, a prospective multicenter trial in which cyclosporine A dose was adjusted based on C2 level. One-year routine biopsies were assessed from 26 patients from two centers. For each biopsy, a section was analyzed by a program of color segmentation imaging, which automatically extracts green color areas characteristic of IF. Results were expressed as percentage of IF and grade (grade 1: <25%, grade 2: 25-50%, and grade 3: >50%).

RESULTS

Mean IF score was 0.35+/-0.04. Quantitative IF grade 1 was observed in 9 biopsies (34.6%), grade 2 in 12 (46.1%), and grade 3 in 5 (19.2%). Diabetes and cytomegalovirus infection were significantly associated with a higher percentage of IF. There was no correlation between the group of randomization and IF. We found a statistical significant correlation between Banff 05 chronic lesions classification and the IF index (P<0.02). Repeated analysis of variance demonstrated an association between high grade of automated IF and a worsening of creatinine clearance (Modification of Diet in Renal Disease) between 1 and 3 years.

CONCLUSIONS

Automatic quantification of IF on routine renal biopsies at one year posttransplant is predictive of long-term allograft function and may assist early diagnosis of the interstitial lesions of chronic allograft injury.

Arteriosclerosis in kidneys from healthy live donors: comparison of wedge and needle core perioperative biopsies

CONTEXT

Although risks associated with live kidney donation are low, there are few pathologic studies of kidneys from live donors, and possible risk factors for development of hypertension or renal insufficiency remain unknown. There are many studies of histopathologic changes in deceased donor kidneys and how these changes affect subsequent graft function; most are based on wedge rather than needle core biopsies.

OBJECTIVE

To examine the frequency and severity of arterial fibrointimal thickening and other pathologic lesions in kidneys from healthy live donors and compare wedge and needle core biopsies as methods for evaluating these changes.

DESIGN

For 36 of 332 live donor renal transplantations performed from January 2004 through November 2006, a wedge biopsy of the transplanted kidney was done prior to and/or after implantation, and a needle core biopsy was done postimplantation or during the ensuing 7 days. For these 36 allografts, we compared pathologic features of the wedge and core perioperative biopsies.

RESULTS

Findings on core and wedge biopsies were similar, except for arterial fibrointimal thickening. Moderate thickening (Banff cv2) was present on 13 core biopsies, and mild thickening (cv1) was present on another 10; by contrast, no wedge biopsies showed cv2 lesions, and only 8 showed cv1. Arterial thickening on core but not wedge biopsies correlated significantly with increasing patient age.

CONCLUSIONS

The findings indicate that needle core biopsies are superior to wedge biopsies for evaluating vascular changes in donor kidneys, and they suggest a need for studies correlating such changes with long-term outcomes of live donors, particularly older donors.

Stress associated proteins metallothionein, HO-1 and HSP 70 in human zero-hour biopsies of transplanted kidneys

Light microscopic alterations reflecting both previous and preservation-induced changes in the donor organ are usually not very distinctive. The ischemia/reperfusion-associated injury depends primarily on the conditions of donor organ preservation. The present study examined human kidney biopsies with special attention paid to the molecular mechanisms of preservation-induced injury preceding reperfusion. Stress-associated proteins hemeoxygenase-1 (HO-1), heat shock protein 70 (HSP 70), and metallothionein (MT) were studied in human zero-hour biopsies of transplanted kidneys prior to reperfusion in 29 patients. Protein expression was evaluated by semiquantitative immunohistochemistry and Western blotting for HO-1 and HSP 70. These findings were correlated with terminal deoxynucleotidyltransferase-mediated 2'-deoxyuridine 5'-triphosphate-digoxigenin nick end labeling (TUNEL) staining and follow up. Compared to controls, MT and HSP 70 expression was significantly higher at zero hour. In contrast, HO-1 and the number of TUNEL-positive cells were not elevated. MT and HO-1 immunoexpression were inversely associated with graft function, and hence, were of prognostic relevance. MT and HSP 70 were sensitive to the duration of cold ischemia. MT and HO-1 are suitable indicators for tissue injury during ischemia and may serve as new predictive markers that need to be validated in further independent studies.

Chronologically different impacts of immunologic and non-immunologic risk factors on renal allograft function

INTRODUCTION

Upon analysis of the risk factors affecting renal graft survival and function, the time-dependent effects of each risk factor should be differentiated from their net effects. To evaluate the chronologically different impacts of risk factors on graft renal function, we reviewed 390 recipients who received a kidney from 1-haplotype-matched living-related donors.

MATERIALS AND METHODS

Until 5-yr post-transplantation (TX), yearly serum creatinine (Scr), 24-h urinary excretion of protein, and their yearly changes were compared by the episodes of acute rejection within 1 yr, the kidney weight to recipient body weight (KW/BW) ratio, the donor/recipient (D/R) age ratio, and the D/R gender pairing. The Kaplan-Meier method, Cox proportional hazard model, ANOVA, and repeated measures ANOVA were each applied for different purposes.

RESULTS

Only the episodes of acute rejection were a significant risk factor affecting graft survival. The episodes of acute rejection, KW/BW ratio, D/R age ratio, and D/R gender pairing consistently and independently had significant influences on Scr. Recipients having the lowest KW/BW ratio (first quartile) or the highest D/R age ratio (fourth quartile) had rapid increments of Scr after 4-yr post-TX. After 3-yr post-TX, there were significant correlations between the number of non-immunologic risk factors present and the yearly changes in Scr.

CONCLUSIONS

Non-immunologic factors had a detrimental effect on renal graft function, especially after 3-yr post-TX. If immunologic risks seem to be similar, size matching, age, and gender pairing should be considered for better long-term graft function in renal TX recipients.

No difference in degree of interstitial Sirius red-stained area in serial biopsies from area under concentration-over-time curves-guided cyclosporine versus tacrolimus-treated renal transplant recipients at one year

Interstitial fibrosis is the main characteristic of chronic allograft nephropathy and long-term graft failure. Cyclosporin (CsA) is thought to be more fibrogenic than tacrolimus. In a prospective, randomized, multicenter trial using a calcineurin-sparing regimen, renal interstitial volume was compared in CsA- and tacrolimus-treated renal transplant recipients by image analysis of Sirius red (SR)-stained cortical areas in protocol biopsies obtained at 6 mo (n = 94) and 12 mo (n = 97) after transplantation. Immunosuppression consisted of CsA or tacrolimus, CD25 mAb, mycophenolate mofetil, and prednisolone. CsA therapy increased the 6-mo risk for subclinical rejection. The prevalence of subclinical rejection was 38.8% in the CsA-treated and 15.2% in the tacrolimus-treated patient group (P = 0.012). Strikingly, no difference in the degree of interstitial SR-stained area was detectable between the two treatment groups. In particular, previous subclinical rejection episodes did not influence the degree of interstitial volume. Also, no difference in GFR occurred at 1 yr, when the mean GFR mounted 63 ml/min. No significant differences in the degree of interstitial SR-stained area could be observed at 6 and 12 mo between CsA- and tacrolimus-treated renal transplant recipients. Although CsA-treated patients developed significantly more subclinical rejections at 6 mo, this did not influence the degree of SR staining or the change in renal function at 1 yr.

Risk factors for chronic allograft nephropathy after renal transplantation: a protocol biopsy study

BACKGROUND

Chronic allograft nephropathy (CAN) leads to chronic allograft dysfunction and loss. Regular renal transplant biopsies may be useful to find risk factors for CAN.

METHODS

We carried out 688 protocol biopsies in 258 patients at 6, 12, and 26 weeks after renal transplantation. Patients with signs of CAN in the biopsy 3 (N= 70, CAN group), and those without (N= 120, non-CAN group), were compared.

RESULTS

Chronic tubulointerstitial changes increased from biopsy 1 to 3 (5% vs. 37%, P < 0.0001). Fifty-six of 190 patients had acute rejection within 6 months (30%), 33 of which were found in protocol biopsies (17%). On univariate analysis, the CAN group had CAN more often at biopsy 2 than the non-CAN group (23% vs. 4%, P < 0.0001), had a lower calculated creatinine clearance at biopsy 1 and 2 (49.4 +/- 25.8 vs. 57 +/- 20.2 mL/min, P= 0.01; 47.3 +/- 21.2 vs. 57.9 +/- 19.5 mL/min, P= 0.001, respectively), had a living donor less often than a brain dead donor (7% vs. 18%, P= 0.045), had a longer cold ischemia time (17.4 +/- 7 vs. 14.9 +/- 8.1 hours, P= 0.04), and had arterionephrosclerosis more often (24% vs. 12%, P= 0.02). On multivariate analysis, the differences in CAN at biopsy 2 (P= 0.001) and lower GFR at biopsy 2 (P= 0.002) were confirmed; in addition, nephrocalcinosis (P= 0.006) and acute rejection (P= 0.046) were found to occur more often.

CONCLUSION

Chronic tubulointerstitial changes develop early after renal transplantation and are associated with reduced kidney function. Risk factors for CAN are arterionephrosclerosis (donor-related), nephrocalcinosis (related to preexisting hyperparathyroidism), a long cold-ischemia time (ischemia-perfusion-related), and acute rejection. Renal functional decline precedes morphologic changes of CAN, expressed as tubular atrophy and interstitial fibrosis.

Favorable outcomes among recipients of living-donor nephrectomy using video-assisted minilaparotomy

BACKGROUND

Minimally invasive, living-donor nephrectomy (LDN) is an attractive procedure for the donor in kidney transplantation (KTx). Its advantages include better cosmesis, shorter hospital stay, and rapid recovery. The most commonly performed, minimally invasive nephrectomy is done laparoscopically. However, the technical challenges, a steep learning curve for the surgeon, the risk of impaired early graft function, and the high cost of the procedure, have prevented minimally invasive LDN from gaining wide acceptance. To overcome these problems, we have developed a new surgical procedure named video-assisted minilaparotomy (VAM) for LDN. VAM-LDN is performed entirely with a small retrieval incision. Moreover, it does not require the induction of pneumoperitoneum, thereby avoiding potential vascular and renal complications.

METHODS

We evaluated the outcome of transplant recipients receiving kidneys with the VAM-LDN procedure by retrospectively comparing the surgical outcomes of patients who underwent KTx with the conventional open nephrectomy (group I, n=82) and VAM-LDN (group II, n=70) procedures from March 1, 1997, to June 30, 2002, at our institution. We compared postoperative complications, patient and graft survival, and graft functions between these two groups during a 12-month follow-up period.

RESULTS

There were no differences in demographic data, ABO compatibility, degree of human leukocyte antigen matching, or method of immunosuppression between the two groups (P >0.05). No significant difference was observed in complications such as delayed graft function, acute rejection, ureter complication, graft failure, or patient's mortality. There was no difference in graft function between the two groups, as determined by serum creatinine level measured during the 12-month follow-up.

CONCLUSION

The short-term recipient outcome was favorable in patients who underwent KTx with the VAM-LDN procedure.

Strategies for ensuring effective surveillance in post-transplant patients: practical organization and clinical evaluation

Results of renal transplantation have improved steadily over the years. This article reviews the current status of patient and graft survival and discusses major causes of mortality and renal allograft failure. Review of recent literature demonstrates that the traditional enemies of transplantation, acute rejection and opportunistic infections are no longer major problems facing transplantation. Chronic graft nephropathy and death with functioning graft due to cardiovascular disease are the main challenges in the current era. An impact of an early graft thrombosis, recurrent renal disease and post-transplant malignancies are also reviewed. Chronic graft nephropathy is examined in a context of differences between two calcineurin inhibitors, cyclosporin microemulsion and tacrolimus. Strategies of post-transplant surveillance are suggested.

Computer-assisted quantification of fibrosis in chronic allograft nephropaty by picosirius red-staining: a new tool for predicting long-term graft function

BACKGROUND

Chronic allograft nephropathy (CAN) has become the predominant limiting factor for long-term transplant survival. A cardinal histomorphologic correlate for CAN is interstitial fibrosis. Currently, no method has been established in routine use that reliably quantifies the extent of interstitial fibrosis in renal grafts. We have used staining with picrosirius red followed by computerized image analysis to study the correlation between graft fibrosis and future development of glomerular filtration rate (GFR) in a group of children with advanced CAN.

METHODS

Renal biopsies were performed in 56 children (mean age, 13.7+/-3.6 years) after a mean period of 4.6+/-3.1 years after transplantation because of significant increases in serum creatinine. All biopsy specimens were stained with picrosirius red. The magnitude of fibrotic tissue was calculated by computerized image analysis. Linear regression analysis was performed correlating the intensity of graft fibrosis and the changes in the GFR at the time points of renal biopsy and 2 years later.

RESULTS

There was a significant positive correlation (r=0.62, P<0.001) between the picrosirius red-stained cortical fractional interstitial fibrosis volume (V(intFib)) and the decrease of GFR within 2 years postrenal biopsy. When V(intFib) was below 5%, 82% of the patients had an increase in GFR within 2 years. Ninety-three percent of the patients with greater than 10% of fibrosis experienced a worsening renal function after 2 years. When comparing patients with stable GFR with patients having a decrease in GFR, a highly significant difference in V(intFib) was found (P=0.008).

CONCLUSIONS

The quantitative measurement of fibrosis by picrosirius red staining appears to be a useful prognostic indicator for estimating long-term graft function in CAN and may provide an easy, fast, and inexpensive tool helpful for treatment decisions in patients developing CAN.

Computerized image analysis of Sirius Red-stained renal allograft biopsies as a surrogate marker to predict long-term allograft function

Chronic allograft nephropathy (CAN) is a major problem in posttransplant management. The lack of a reliable and early surrogate marker of CAN has hampered patient care and research. In this study, the Cortical Fractional Interstitial Fibrosis Volume (V(IntFib)), quantitated with computerized image analysis of Sirius Red-stained protocol biopsies, was examined as a potential surrogate for time to graft failure (TTGF) in 68 renal allograft recipients. At 6 mo posttransplant, V(IntFib) was highly correlated with TTGF (r = 0.64, P < 0.001). Both the Banff Chronic Sum and the Acute Sum Scores were also correlated with TTGF, but less strongly (r = 0.28, P < 0.02; r = 0.35, P < 0.003, respectively). As V(IntFib) was not correlated with the Banff Chronic Score, a multivariate model was created that incorporated V(IntFib) and both Acute and Chronic Banff pathology. This model was highly correlated with TTGF (r = 0.7, P < 0.0001). These findings suggest that V(IntFib) determined by computerized image analysis of Sirius Red-stained protocol biopsies at 6 mo posttransplant, with or without incorporation of Banff acute and chronic scoring, may provide an early surrogate for time to graft failure in renal allograft recipients.

Complement activation in early protocol kidney graft biopsies after living-donor transplantation

BACKGROUND

To gain insight into complement activation in kidney grafts, we studied the deposition of components from all complement pathways in protocol biopsies from living-donor recipients that were taken 1 week (median 7 days) after transplantation.

METHODS

Graft protocol biopsies (n=37) were taken consecutively and stained for two-color immunofluorescence, with antibodies to C4d, C3, C1q, factor B, C6, terminal C5b-9 complement complex, mannose-binding lectin (MBL), and MBL-associated serine protease-1, combined with an endothelial marker. Light and electron microscopy were performed in all cases. Clinical acute rejection (AR), graft loss, and long-term kidney function were recorded. Baseline biopsies from 15 of the patients served as controls.

RESULTS

Endothelial C4d deposition was demonstrated in peritubular capillaries in 11 of 37 cases (30%), of which 9 of 11 (82%) experienced clinical AR but only 6 of 11 (55%) experienced AR as defined by histopathologic criteria. Biopsies from three patients, two with early graft loss, showed diffuse global C4d in the glomerular endothelium with codeposition of C3 in all patients and MBL-associated serine protease-1 in one patient. Focal peritubular capillary C3 deposition was found in two additional C4d-positive cases with AR. No posttransplant deposition was demonstrated for the other components.

CONCLUSIONS

Early diffuse C4d deposition in the kidney graft capillaries is closely related to acute humoral rejection, whereas focal staining may occur with mild AR or, rarely, without rejection. Codeposition of C3 indicates early AR with a higher risk of graft loss. In most cases, activation was limited to C4d, indicating efficient in situ regulation of complement activation.

Risk factors for late kidney allograft failure

BACKGROUND

While graft survival rates in the short term have improved dramatically, only a modest improvement has been shown in long-term graft survival rates. We evaluated the causes of late failure in renal allograft recipients treated with cyclosporine A (CsA).

METHODS

A total of 864 adults with a functioning graft at one year were evaluated. The end points were dialysis or death with a functioning graft.

RESULTS

The 13-year patient and graft survival probabilities were 0.82 and 0.64, respectively. The graft half-life was 20.1 years and the pure graft half-life was 31.1 years. At multivariate analysis, plasma creatinine at one year (P = 0.0006; RR 1.72), low-density lipoproteins (LDL) at one year (P = 0.0014; RR 1.65), older age (P = 0.0128; RR 1.50) and delayed graft function (P = 0.0350; RR 1.45) were associated with the end point. Chronic allograft nephropathy was the cause of failure in 97 patients, death in 70, recurrence of glomerulonephritis in 24, other events in 6. Cardiovascular complications were the most frequent cause of death. Post-transplant cardiovascular events were associated with: pre-transplant cardiovascular events (P = 0.0012; RR 2.65), older age (P = 0.0001; RR 2.46), pre-transplant arterial hypertension (P = 0.0249; RR 1.57), smoking (P = 0.0235; RR 1.29), duration of dialysis (P = 0.0229; RR 1.28). Mean serum cholesterol, LDL and triglycerides were each significantly associated post-transplant cardiovascular events.

CONCLUSIONS

The graft half-life was 20 years. Chronic allograft nephropathy was the leading cause of late failure, followed by death. If the data were censored by death, the projected pure graft half-life would be 31.1 years. Pre-transplant selection and preparation of the candidate as well as appropriate life style are recommended to improve life expectancy and extend graft survival.

Chronic allograft nephropathy--biopsy findings and outcome

BACKGROUND

Chronic allograft nephropathy (CAN) is a composite term for various types of damage to a kidney transplant. We wanted to analyse its components in relation to baseline biopsy findings, transplant function, and outcome.

METHODS

Among renal transplantations performed from 1985 to 1997, 156 were identified where allograft biopsies had been obtained on clinical indication 6 months after transplantation or later, baseline biopsies were available in each case and the patient's original disease was known. Time after transplantation was median 2.2 years (range 0.5-13). The biopsies were reviewed and the Banff 1997 CAN score obtained.

RESULTS

All but one late biopsy showed some CAN grade, 48% grade II, and 7.5% grade III. Acute tubulointerstitial rejection was seen in 9% but vascular rejection in only 3%. Arterial wall thickening was present in 66% of the late biopsies, correlated with donor age and its presence at baseline but also with time after transplantation. The Banff CAN score and serum creatinine level were both independent predictors of further graft survival, relative risk 0.35 (confidence interval 0.15-0.82, P=0.015) for CAN grade I vs III and 0.30 (0.14-0.67, P=0.003) for serum creatinine <170 vs >250 micromol/l. Presence of arterial wall thickening had no prognostic impact.

CONCLUSION

The CAN grade is predictive of further graft survival independently of the serum creatinine level. Interstitial fibrosis and tubular atrophy are more prominent features of chronic graft damage than vascular rejection. Unspecific arterial wall thickening is partly dependent on baseline conditions and lacks prognostic impact in this late stage.

Renal hemodynamic response to maximal vasodilating stimulus in healthy older subjects

BACKGROUND

It is still unclear whether age per se is associated with preservation of renal functional reserve, that is, of the increase in glomerular filtration rate (GFR) induced by appropriate vasodilating stimulus.

METHODS

To gain insights into this issue, we evaluated the renal response to a maximal vasodilating stimulus, represented by the combined infusion of mixed amino acid solution (AA) and dopamine at renal dose (D), in 10 young subjects (median age of 30 years, range of 19 to 32) and in 11 subjects of older age (median age of 67 years, range of 65 to 76). Two further age-matched groups of young (N = 15) and older (N = 11) living kidney donors underwent renal needle biopsy immediately before nephrectomy to perform semiquantitative scoring (0 to 3) of arteriosclerosis in intrarenal arteries. All of the study subjects were nonsmokers with healthy status proven by extensive diagnostic evaluation excluding any risk factor of renal dysfunction.

RESULTS

Basal renal plasma flow (RPF) and GFR were proportionally lower in older subjects (RPF, 361 +/- 29 vs. 618 +/- 34 mL/min/1.73 m(2), P < 0.001; GFR, 79 +/- 4 vs. 127 +/- 5.8 mL/min/1.73 m(2), P < 0.001). After AA + D, a significant increase of RPF and GFR was observed in both groups, but the older subjects exhibited a smaller percentage increment (RPF, 25.5 +/- 4.8 vs. 42.4 +/- 5.8, P < 0.05; GFR, 19.6 +/- 5.7 vs. + 33.8 +/- 6.4, P < 0.05). Furthermore, the maximal vasodilating stimulus was not able to restore renal hemodynamics in older subjects to the level measured in young controls at baseline. Renal vascular resistances were higher (P < 0.05) in the older subjects both at baseline (0.19 +/- 0.02 vs. 0.09 +/- 0.004 mm Hg/mL/min) and after AA + D (0.14 +/- 0.01 vs. 0.06 +/- 0.004). Light microscopy examination detected the presence of a greater degree of arteriosclerosis at the level of interlobular and arcuate arteries (0.89 +/- 0.15 vs. 0.45 +/- 0.08) and interstitial fibrosis/tubular atrophy (1.18 +/- 0.13 vs. 0.53 +/- 0.13) in older than in young subjects.

CONCLUSIONS

Therefore, aging has adverse effects on renal function despite the absence of any risk factor for renal disease, including chronic smoking: (1) GFR and RPF are lower, and (2) the renal response to maximal vasodilating stimulus is impaired. These aging-related alterations of renal hemodynamics are possibly due to organic lesions in renal vasculature.

Protocol biopsies in the management of renal allograft recipients

The safety of the renal allograft biopsy and the standardization of allograft histopathology interpretation have renewed interest in the protocol biopsy. Recent studies in the areas of 'marginal' donors, surveillance of acute rejection, molecular biology and chronic rejection are discussed.

Delayed graft function influences renal function, but not survival

BACKGROUND

In renal transplantation, the impact of delayed graft function (DGF) on prognosis is controversial. We analyzed the risk factors of DGF and its impact on graft function and prognosis.

METHODS

Seven hundred thirty-four cadaveric renal transplants performed between 1983 and 1997 were analyzed. DGF was diagnosed when serum creatinine levels increased, remained unchanged, or decreased less than 10% per day in three consecutive days in the first week after transplantation. Creatinine clearances of more or less than 50 or 30 mL/min at one year were used as cut-off points for optimal and suboptimal graft function, respectively. The logistic regression model was used to identify independent risk factor related to DGF and renal function one year after transplantation. The Cox regression model was used to examine the influence of DGF on long-term graft survival.

RESULTS

Multivariate analysis revealed the following risk factors for DGF: recipient pretransplantation mean arterial blood pressure of less than 100 mm Hg (OR = 2.08, 95% CI, 1.43 to 3.03), female donor to male recipient combination (OR = 1.55, 95% CI, 1.02 to 2.35), donor age of more than 50 years (OR = 2.21, 95% CI, 1.49 to 3.26), cold ischemia time of more than 28 hours (OR = 1.78, 95% CI, 1.19 to 2.63), and peak panel reactive antibodies of more than 50% (OR = 1.7, 95% CI, 1.15 to 2.55). The incidence of DGF was one of the independent risk factors for suboptimal graft function at one year (OR = 1.68, 95% CI, 1.14 to 2.48), together with donor age of more than 50 years (OR = 2.39, 95% CI, 1.61 to 3.57), female donor gender (OR = 1.99, 95% CI, 1.42 to 2.78), the occurrence of acute rejection episodes (OR = 2.66, 95% CI, 1.87 to 3.78), peak panel-reactive antibodies of more than 50% (OR = 1.67, 95% CI, 1.15 to 2.47), and sharing of 1 to 3 versus 4 to 8 cross-reactive antigens groups (OR = 1.65, 95% CI, 1.09 to 2. 49). Moreover, DGF was one of the two independent risk factors for acute rejection episodes, but it had no independent effect on graft survival.

CONCLUSION

Several risk factors for DGF were identified, of which a low recipient pretransplant mean arterial blood pressure, the transplantation of kidneys from female donors to male recipients, and a prolonged cold ischemia time are potentially avoidable. Although DGF is one of the several risk factors of acute rejection and suboptimal function at one year, it is not independently associated with an increased rate of graft loss.