Time-zero Biopsies Research Articles

Tissue Expression of Aquaporin 2 Is Correlated to Urine Output and Allograft Function in Sensitized Kidney Transplant Patients.

Salt and water disturbances often occur during acute kidney allograft dysfunction that contribute to graft failure, but this condition has been poorly investigated in the alloreactivity setting. We evaluated the tissue expression of aquaporins (AQP1 and AQP2) and the epithelial sodium channel (ENAC) in kidney biopsy specimens from sensitized kidney transplant recipients. Eighty-six biopsy specimens from 33 sensitized patients were divided into 3groups according to clinical context: time-zero (n= 9), protocol (n= 9), and indication (n= 68). The indication biopsy specimens were further divided into 3 subgroups according to the presence of acute tubular necrosis or rejection. Normal kidney tissue samples (n= 6) served as the control specimens. Immmunohistochemical expression of AQP1, AQP2, and ENAC was determined by using image analyzing software. Significantly lower AQP1 expression was observed in the time-zero and indication biopsy specimens with rejection compared with control specimens (P= .03 and P= .04, respectively). AQP2 expression was significantly lower in patients with an indication biopsy specimen compared with control and protocol biopsy specimens (P= .05 and P= .005). For ENAC, a lower expression was noted in the indication biopsy specimens compared with the control specimens (P= .04). Both AQP1 and AQP2 tissue expressions were significantly correlated to urine output (r= 0.45 and r= 0.32; P= .001 and P= .02), and AQP2 was correlated with the glomerular filtration rate estimated by using the Modification of Diet in Renal Disease Study equation at biopsy (r= 0.23; P= .05). These findings partially confirm previous experimental data showing downregulation of AQP1 expression after ischemia/reperfusion injury and during rejection. AQP2 downregulation seems to be rejection-independent, occurring during deteriorating or poor kidney graft function.

Oxidative-stress-induced biosignatures: a predictor of allograft dysfunction?

BackgroundChronic graft dysfunction is the commonest cause of graft loss and is affected by perioperative factors. In liver transplantation, perioperative oxidative stress precipitates a senescence-associated secretory phenotype in biliary epithelial cells and this could be one of the factors responsible for fibrosis and allograft dysfunction. We aimed to examine effects of oxidative stress on biliary epithelial cells and assess the transcriptome of time-zero liver transplant biopsies for biomarkers of allograft dysfunction. MethodsTo model oxidative stress, the biliary epithelial cell H69 cell line was exposed to hydrogen peroxide in vitro. Immunofluorescence was performed post injury for protein expression associated with senescence and epithelial-mesenchymal transition. Similarly gene expression was analysed with both Taqman real-time PCR and a SYBR Green custom gene array (Thermo Fisher, Waltham, MA, USA). These experiments were repeated in triplicate. Similarly, the transcriptome of six time-zero liver transplant biopsy samples were analysed to examine in-vivo effects. A one-way ANOVA was performed for statistical analysis. FindingsOxidative stress induced gene expression upregulation of senescence marker p21 (p<0·001) and transforming growth factor β2 (TGFβ2) (p<0·001) during the first 48 h after injury to biliary epithelial cells. After this time these cells had increased expression of mesenchymal proteins (α smooth muscle actin and vimentin, p<0·001) with a decrease in epithelial markers (ZO-1 and E-cadherin, p<0·001). In-vitro pharmacological blockade of the ALK5 component of the TGFβ receptor abrogated this response. Data from the time-zero patient biopsy samples highlighted further potential candidate biomarkers, but none reached statistical significance. InterpretationOur results show that oxidative stress induces a senescence phenotype that triggers an epithelial dedifferentiation in biliary epithelial cells through TGFβ2 production. Marginal organs are particularly susceptible to the damage from oxidative stress. In conjunction with normothermic reperfusion, these targets might provide a unique opportunity in the pretransplant optimisation of donor organs, potentially minimising the impact of ischaemia reperfusion injury and allograft dysfunction. FundingNewcastle University Shire Bursary, Wellcome Trust Clinical Research Training Fellowship.

Preimplantation Biopsy Predicts Delayed Graft Function, Glomerular Filtration Rate and Long-Term Graft Survival of Transplanted Kidneys

Background The predictive value of preimplantation biopsies for long-term graft function is often limited by conflicting results. The aim of this study was to evaluate the influence of time-zero graft biopsy histological scores on early and late graft function, graft survival and patient survival, at different time points. Methods We retrospectively analyzed 284 preimplantation biopsies at a single center, in a cohort of recipients with grafts from live and deceased donors (standard and nonstandard), and their impact in posttransplant renal function after a mean follow-up of 7 years (range 1–16). Implantation biopsy score (IBS), a combination score derived from 4 histopathological aspects, was determined from each sample. The correlation with incidence of delayed graft function (DGF), creatinine clearance (1st, 3rd and 5th posttransplant year) and graft and patient survival at 1 and 5 years were evaluated. Results Preimplantation biopsies provided somewhat of a prognostic index of early function and outcome of the transplanted kidney in the short and long term. In the immediate posttransplantation period, the degree of arteriolosclerosis and interstitial fibrosis correlated better with the presence of DGF. IBS values between 4 and 6 were predictive of worst renal function at 1st and 3rd years posttransplant and 5-year graft survival. The most important histological finding, in effectively transplanted grafts, was the grade of interstitial fibrosis. Patient survival was not influenced by IBS. Conclusions Higher preimplantation biopsy scores predicted an increased risk of early graft losses, especially primary nonfunction. Graft survival (at 1st and 5th years after transplant) but not patient survival was predicted by IBS.

Wedge Versus Core Biopsy at Time Zero: Which Provides Better Predictive Value for Delayed Graft Function With the Remuzzi Histological Scoring System?

BackgroundHistopathological features on time-zero renal biopsies correlate with graft outcome after renal transplantation. With increasing numbers of marginal donors, assessment of pre-implantation graft quality is essential. The clinician's choice of wedge or core biopsy is performed without evidence of efficacy or safety. This study aims to compare the information derived from wedge biopsy versus core biopsy. MethodsProspective evaluation of 37 wedge biopsies and 30 core biopsies was performed. Histopathological data were collected on number of glomeruli and arterioles observed, and Remuzzi scoring for glomerulosclerosis, tubular atrophy, interstitial fibrosis, and arteriolar narrowing was performed. Clinical data on delayed graft function (DGF) were also collated. Sensitivity, specificity, and positive and negative predictive values for DGF were compared. ResultsPatient demographics between the two cohorts were comparable. No complications of biopsies occurred; 81% of wedge biopsies versus 50% of core biopsies had >10 glomeruli (P = .01), whereas 32% of wedge biopsies and 57% of core biopsies had >2 arterioles (P = .02). Wedge biopsies were more likely to identify pathology with more glomerulosclerosis, tubular atrophy (P < .01), and interstitial fibrosis (P < .01). There was a non-significant trend toward high Remuzzi scores in wedge biopsy (22% versus 7% with Remuzzi ≥4; P = .12). The sensitivity and positive predictive value of Remuzzi ≥4 for predicting DGF was better on wedge biopsy (45.5% versus 0%; P < .01 and 62.5% versus 0%; P < .01, respectively). ConclusionsWedge biopsies were safe and superior to core biopsies for identifying clinically significant histopathological findings on pre-implantation renal biopsy. We believe that the wedge biopsy is the method of choice for time-zero biopsies.

Correlation of Histopathologic Findings of Non-Graft Threatening Preservation/Reperfusion Injury in Time-Zero Liver Needle Biopsies With Short-Term Post-transplantation Laboratory Alterations.

Background:Early post-transplantation alterations in liver tests are caused by a variety of etiologies including rejection, biliary or vascular complications, and preservation/reperfusion injury (PRI).Objectives:The aim of this study was to show the correlation between histopathologic changes of PRI and the alterations in liver tests in the early post-transplantation period.Materials and Methods:Between April 2013 and August 2014, histopathologic findings of protocol, time-zero, Tru-Cut, liver needle biopsies were evaluated in 94 cases of cadaveric liver transplantation. The histopathologic changes included ballooning degeneration, micro- and macro-vesicular steatosis, bilirubinostasis, apoptotic cells, bile plugs and neutrophilic infiltration. These histopathologic changes were compared with the early (15 days) post-transplantation liver laboratory findings.Results:Clinico-pathologic evaluation of all 94 cases was done by assessment of PRI findings in time-zero biopsies and possible causes of allograft injury were appraised. In 21 patients, a specific cause for allograft injury was found including rejection and/or surgical complications. In the remaining 73 cases, there was no specific cause for allograft injury and histopathologic findings of time-zero liver needle biopsies supported PRI. We classified liver laboratory tests alterations as: hepatocellular damage (elevation of transaminases and lactate dehydrogenase), cholestatic damage (elevation of alkaline phosphatase and total bilirubin) and mixed. Hepatocellular and cholestatic alterations in liver function tests were associated with the presence of marked apoptotic bodies and neutrophilic aggregates in time zero biopsies, respectively. On the other hand, macrovesicular steatosis was dominantly associated with mixed (hepatocellular and cholestatic) laboratory alterations of liver tests.Conclusions:Any discrepancy between histopathologic changes in time-zero biopsies and pattern of early liver laboratory alterations may be considered as a warning for causes other than PRI.

Analysis of ischemia/reperfusion injury in time-zero biopsies predicts liver allograft outcomes.

Ischemia/reperfusion injury (IRI) that develops after liver implantation may prejudice long-term graft survival, but it remains poorly understood. Here we correlate the severity of IRIs that were determined by histological grading of time-zero biopsies sampled after graft revascularization with patient and graft outcomes. Time-zero biopsies of 476 liver transplants performed at our center between 2000 and 2010 were graded as follows: nil (10.5%), mild (58.8%), moderate (26.1%), and severe (4.6%). Severe IRI was associated with donor age, donation after circulatory death, prolonged cold ischemia time, and liver steatosis, but it was also associated with increased rates of primary nonfunction (9.1%) and retransplantation within 90 days (22.7%). Longer term outcomes in the severe IRI group were also poor, with 1-year graft and patient survival rates of only 55% and 68%, respectively (cf. 90% and 93% for the remainder). Severe IRI on the time-zero biopsy was, in a multivariate analysis, an independent determinant of 1-year graft survival and was a better predictor of 1-year graft loss than liver steatosis, early graft dysfunction syndrome, and high first-week alanine aminotransferase with a positive predictive value of 45%. Time-zero biopsies predict adverse clinical outcomes after liver transplantation, and severe IRI upon biopsy signals the likely need for early retransplantation.

Baseline Donor Chronic Renal Injury Confers the Same Transplant Survival Disadvantage for DCD and DBD Kidneys

Histological assessment of baseline chronic kidney injury may discriminate kidneys that are suitable for transplantation, but has not been validated for appraisal of donation after circulatory death (DCD) kidneys. 'Time-zero' biopsies for 371 consecutive, solitary, deceased-donor kidneys transplanted at our center between 2006 and 2010 (65.5% DCD, 34.5% donation after brain death [DBD]) were reviewed and baseline chronic degenerative injury scored using Remuzzi's classification. High scores correlated with donor age and extended criteria donors (42% of donors), but the spectrum of scores was similar for DCD and DBD kidneys. Transplant outcomes for kidneys scoring from 0 to 4 were comparable (1 and 3 year graft survival 95% and 92%), but were much poorer for kidneys scoring ≥5, with 1 year graft survival only 73%, and 12.5% suffering primary nonfunction. Critically, high Remuzzi scores conferred the same survival disadvantage for DCD and DBD kidneys. On multi-variable regression analysis, time-zero biopsy score was the only independent predictor for graft survival, whereas one-year graft estimated glomerular filtration rate (eGFR) correlated with donor age and biopsy score. In conclusion, the relationship between severity of chronic kidney injury and transplant outcome is similar for DCD and DBD kidneys. Kidneys with Remuzzi scores of ≤4 can be implanted singly with acceptable results.

The Significance of Time-Zero Biopsy for Graft Renal Function After Deceased Donor Kidney Transplantation.

The Significance of Time-Zero Biopsy for Graft Renal Function After Deceased Donor Kidney Transplantation.

The Impact of Time-Zero Biopsy on Early Graft Outcomes After Living Donor Kidney Transplantation

BackgroundIn contrast with deceased donor transplantation, the clinical significance of pathologic findings in time-zero biopsies after living donor kidney transplantation are rarely reported, due to the expectation that histologic findings and renal function are normal. The aim of this study was to identify subclinical pathologic findings in living donors and examine the effect on early graft renal function. MethodsBetween December 2006 and July 2011, 146 living-donor kidney transplant recipients were enrolled in this study. We retrospectively analyzed donor and recipient-related clinical parameters, and post-transplant 6 months and 1 year estimated glomerular filtration rate (eGFR) as early graft renal function. Time-zero biopsies were evaluated using the 2007 Banff criteria. ResultsMost abnormal histologic findings were of mild degree as determined by Banff scores. Global glomerulosclerosis (GS, 35.6%), tubular atrophy (CT, 36.3%), interstitial fibrosis (CI, 20.5%), vascular fibrous intimal thickening (CV, 4.1%), arteriolar hyaline thickening (AH, 14.4%), interstitial inflammation (I, 3.4%) were pathologic findings in time-zero biopsies. The univariate analysis revealed that donor age and gender were significantly associated with eGFR at post-transplant 6 months and at 1 year (P < .05). Furthermore, GS and CT were significantly associated with early graft renal function (P < .05). However, multivariate linear regression analysis showed only donor age was significantly associated with early graft renal function (P = .001). ConclusionA mild degree of subclinical, pathologic findings on time-zero biopsy did not affect early graft renal function in living-donor kidney transplantation.

Epigenetic Analysis of the TSDR of FOXP3 Demonstrates That Natural Treg Infiltrate the Cardiac Allograft Already before an Acute Rejection Episode

Purpose Two subtypes of FOXP3+ regulatory T cells (Treg) have been identified. Natural (n) Treg originate in the thymus, while antigen specific induced (i) Treg are induced in the periphery by antigen exposure and cytokines. Their role in regulating allogeneic responses in immunosuppressed heart transplant patients is unknown. Therefore we investigated the origin of graft infiltrated FOXP3+ Treg and examined their immunosuppressive capacities by studying FOXP3 characteristics during acute rejection (AR) and immunological quiescence. Methods and Materials In total, 91 endomyocardial biopsies (EMB) were analyzed of 42 patients, 28 patients experienced at least 1 rejection episode requiring anti-rejection therapy (ISHLT rejection grade 2R; rejectors) and 14 patients remained free from rejection (non-rejectors). The percentage of demethylated TSDR (Treg Specific Demethylated Region) in the FOXP3 gene represents the percentage of nTreg. FOXP3 mRNA levels represent the total regulatory T cell population. Results In time-zero biopsies, no evidence for nTreg was detected. In grade 1R EMB of non-rejectors no significant accumulation of nTreg was observed. However, in rejectors, in all grade 1R EMB (taken before AR) and 2R EMB (AR) nTreg were detected with a significant higher percentage compared to EMB of non-rejectors (p≤0.001). FOXP3 mRNA levels significantly increased after transplantation with the highest expression in grade 2R EMB. Remarkably, no significant difference was observed in the FOXP3 mRNA levels in 1R EMB of non-rejectors compared to 1R EMB of rejectors (p=0.32), while the latter had significant evidence for a higher percentage nTreg (p=0.001), suggesting more iTreg in the non-rejectors. Conclusions These data show that nTreg infiltrate the cardiac allograft already before histologically proven AR, indicating that nTreg are unable to prevent the rejection process. The characteristics of the FOXP3 gene in EMB of non-rejectors support a role for antigen specific iTreg in the prevention of rejection.

Latent Abnormal Pathology Affects Long-Term Graft Function in Elder Living Renal Allograft Recipients

Objective. This study evaluated the long-term effects and clinical significance of latent abnormal pathology on elder living donor kidney graft function after renal transplantation in China. Methods. One-hundred and thirty-eight living donor renal transplantations have been carried out at our hospital in recent years. Of these, 72 Time-Zero biopsies were performed and used in this analysis. Clinical data were retrospectively measured at 3, 6, 12, and 24 months after renal transplants. Relationships and effects from biopsy results taken from implanted donor kidney grafts were analyzed. Results. Time-Zero biopsy pathology results from donor kidneys showed that 48.61% of donor kidneys had latent abnormal changes; arterial lesions of donor kidneys had significant effects on the renal function of grafts after 2 years' transplantation; correlations between donor age and arterial lesions were significant; and Time-Zero biopsy pathology results could help predict the long-term function of a renal graft. Conclusions. Existing latent pathological changes of an elder living donor kidney before transplantation could affect long-term renal function. Whether a senior donor is used should be very carefully considered.

Epigenetic Analysis Demonstrates that Natural Treg Only Infiltrate the Cardiac Allograft During an Acute Rejection Episode

Introduction: FOXP3+ regulatory T cells (Treg) infiltrate the cardiac allograft after transplantation; however, it is unknown whether these infiltrating cells are derived from the thymus (nTreg) or are induced by antigen in the periphery (iTreg). Using demethylation of the FOXP3 gene as a marker for nTreg, we investigated the origin of infiltrating cells in heart transplant biopsies during both immunological quiescence and acute rejection. Methods: The proportion of demethylated FOXP3 DNA was determined with a quantitative PCR based method with a sensitivity limit of 0.06%. In total, 66 EMB (endomyocardial biopsies) were analyzed of 17 heart transplantation patients who experienced at least 1 rejection episode requiring anti-rejection therapy (ISHLT rejection grade 2R; rejectors) within the first 3 months after transplantation and 9 patients who remained free from rejection during this period (non-rejectors). EMB were taken before transplantation (time-zero biopsies; n=24), before and during acute rejection (AR) for the rejectors (n=28) and within the first 3 months for the non-rejectors (n=14). Results: In time-zero biopsies, no evidence for nTreg was detected. However, after transplantation the proportion of nTreg marker significantly increased in the EMB where cellular infiltrates were present. Grade 1R EMB (n=19) displayed a proportion of 0.22% nTreg and grade 2R EMB (n=16) 0.52% nTreg (p< 0.0001 versus time-zero). Within the grade 1R EMB, including 9 EMB from rejectors and 10 EMB from non-rejectors, the proportional increase in nTreg marker was predominantly observed in the rejectors (0.51% versus 0.05% for non-rejectors; p< 0.01). In all EMB from non-rejectors (0R and 1R) no evidence for accumulation in nTreg marker was observed. Conclusion: In conclusion, rejectors display a higher proportion of nTreg marker after heart transplantation, already before histologically proven AR occurs. This indicates that nTreg home in the graft during alloreactivity where they dampen rather than prevent the rejection process.

Results of Kidney Transplantation from High–Terminal Creatinine Donors and the Role of Time-Zero Biopsy

Background Deceased-donor kidney transplantation (DDKT) from high–terminal creatinine donors is associated with lower graft survival. These kidneys may be considered for discarding, worsening the organ shortage crisis. Using time-zero biopsy for histologic evaluation of these kidneys, we identified those organs eligible for transplantation, seeking to achieve better graft utility with comparable outcomes. Methods From April 2004 to April 2008, 55 patients underwent DDKT. A time-zero biopsy was used to examine glomerulosclerosis, interstitial fibrosis, tubular atrophy, and arteriolar narrowing. A scoring system was used to determine a discard. Results Twenty-five patients received DDKT from donors whose terminal creatinine levels were >2.0 mg/dL (high terminal creatinine, HTC group) and 30 from donors whose terminal creatinine levels were <2.0 mg/dL (low terminal creatinine, LTC group). Patients who accepted kidneys from HTC donors had shorter waiting times ( P = .011) but a higher incidence of delayed graft function after transplantation ( P < .001). Nonetheless, 5-year graft survival rates were similar between the two groups. Conclusions With a time-zero biopsy for histologic evaluation, kidneys recovered from high–terminal creatinine donors can be transplanted to overcome the organ shortage while achieving reasonable graft survival.

Time-Zero Renal Biopsy in Living Kidney Transplantation: A Valuable Opportunity to Correlate Predonation Clinical Data With Histological Abnormalities

Living kidney donation is increasing as a partial solution for wait-listed patients. Despite properly followed guideline criteria for donor selection, current reports identify unsuspected renal pathology at preimplantation or time-zero biopsy (T0-RBx). T0-RBx was evaluated for following: interstitial fibrosis (IF), tubular atrophy (TA), arteriolar hyalinosis (AH), mesangial increase (MI), and glomerulosclerosis (GS). Predonation data were demography, body weight, body mass index (BMI), systolic/diastolic blood pressure (BP), serum creatinine (SCr), estimated glomerular filtration rate (eGFR), and proteinuria. Two hundred nineteen T0-RBx were analyzed. Of these 54.4% had abnormal findings, namely, IF in 29%, TA in 13%, MI in 12%, AH in 10%, and GS in 10%. Mean clinical data were as follows: age 35.4+/-10 years, weight 66.27+/-10.14 kg, BMI 25.53+/-2.99, systolic BP 115+/-9 mm Hg, diastolic BP 74+/-7 mm Hg, SCr 0.91+/-0.25 mg/dL, eGFR 96+/-16.65 mL/min, and proteinuria 70.25+/-62.8 mg/24 hr. A total of 56.7% were women. IF correlated to age (r=0.22, P=0.001) and SCr (r=0.19, P=0.005); TA to diastolic BP (r=0.15, P=0.03) and proteinuria (r=0.20, P=0.009); AH to SCr (r=0.15, P=0.02) and eGFR (r=-0.16, P=0.018); MI to BMI (r=0.13, P=0.047). Multivariate analysis failed to sustain the significant associations found on bivariate analysis, most likely due to a low event/parameter relation and sample size. A significant correlation was established between T0-RBx findings and clinical predonation parameters. Whether these mild histologic findings at the time of kidney donation represent a higher risk for the remaining kidney ought to be evaluated during follow-up. In an era, when living kidney donation is increasing, we advise closer donor surveillance to modify risk factors that participate in kidney damage progression.

Glomerular volume and renal histology in obese and non-obese living kidney donors

The link between obesity and renal disease is unclear, and there is no consensus as to whether obese individuals are at increased risk for kidney disease after living kidney donation if they otherwise meet acceptance criteria. We retrospectively studied time-zero (implantation) biopsies in 49 obese (body mass index (BMI) > or = 30 kg/m2) and 41 non-obese (BMI < 30 kg/m2) renal donors that met acceptance criteria. We found that our obese donor population had higher systolic blood pressure (P < 0.001 vs non-obese) and higher absolute iothalamate clearance (P = 0.001 vs non-obese) before donation. The obese donors had larger glomerular planar surface area compared to non-obese controls (P = 0.017), and this parameter correlated with patient weight and urinary microalbumin excretion. Detailed examination of the biopsies revealed that although most histologic findings were similar between groups, the obese donors had more tubular dilation (P = 0.01), but less tubular vacuolization (P = 0.02) than the non-obese controls. There was also a trend toward more arterial hyalinosis in the obese patients than controls (P = 0.08). From these data, our studies detected subtle differences in donor organs obtained from obese compared to non-obese individuals. Further studies should be carried out to quantify the long-term impact of these findings.

Living kidney donors and hypoxia-inducible factor-1alpha.

Hypoxia inducible factor (HIF)-1, a heterodimeric transcription factor composed of alpha and beta subunits, is induced in the adaptive response to hypoxia and is critical for initiating the transcriptional activation of growth factors. We speculate that prolonged ischemia and hypoxia time leads to the production of HIF-1alpha, which in turn induces the production of fibrogenic cytokines in the graft. To investigate our hypothesis, we measured the expression of HIF-1alpha in time-zero biopsy specimens from living-donor kidneys (< or =2.5 hr of ischemia) and cadaveric donor kidneys (12-32 hr of ischemia). By real time reverse-transcriptase polymerase chain reaction analysis, the mRNA expression level of HIF-1alpha was fivefold lower in time-zero biopsy specimens from living-donor kidneys than in specimens from cadaveric donor kidneys. In these time-zero biopsy specimens, the mRNA expression level of the fibrogenic cytokine transforming growth factor-beta was also significantly lower (twofold). Low HIF-1alpha mRNA expression levels correlate with short ischemia times and prevent the transcription of fibrogenic cytokines that initiate the irreversible process of graft fibrosis.

Interstitial expression of alpha-SMA: an early marker of chronic renal allograft dysfunction.

Renal myofibroblast infiltration has been shown to be strongly associated with renal function decline in several chronic renal diseases. The purpose of the present study was to investigate whether early detection of myofibroblast infiltration using alpha-smooth-muscle actin (alpha-SMA) expression in time-zero biopsies predicts renal allograft dysfunction. We studied renal tissue from 38 renal transplant patients from whom biopsies had been taken after vascular anastomosis during transplantation to ascertain whether myofibroblasts infiltration predicts renal graft survival. Immunohistochemistry was performed on time-zero biopsies to determine alpha-SMA expression, and this was compared to annual glomerular filtration rate (GFR) variation and other parameters including cold ischaemic time (CIT), donor and recipient age, number of acute rejections, and delayed graft function (DGF). GFR was measured by inulin clearance during of 3 years of follow-up after the transplantation. Progressors were defined as patients with an annual GFR decline >5 ml/min/year. We found a significant correlation between interstitial alpha-SMA expression in time-zero biopsies and GFR evolution during the post-transplantation course (r=0.60, P<0.001). Although progressors had greater interstitial alpha-SMA expression than non progressors (7.9+/-0.7 vs 4.3+/-0.4%), they showed only a tendency towards higher glomerular alpha-SMA expression. In addition, progressors had more interstitial fibrosis in time-zero biopsies than non-progressors. There was no relationship between alpha-SMA expression and CIT, donor and recipient ages, number of acute rejections, and occurrence of DGF. This study suggests that alpha-SMA evaluation in time-zero biopsies, especially the combination of alpha-SMA expression and interstitial fibrosis, can strongly predict chronic renal allograft dysfunctions.

Hypertension is an independent predictor of delayed graft function and worse renal function only in kidneys with chronic pathological lesions.

Delayed graft function (DGF) has been identified as one of the principal correlates of poor graft survival in cadaveric renal transplantation. However, its risk factors and clinical predictors have been poorly elucidated. We analyzed the risk factors of DGF with a specific emphasis on the role of histological damage of donor kidney. Then, we also studied the impact of DGF, and donor factors affecting DGF, on kidney graft function over the first year after engraftment in 100 consecutive cadaveric renal transplant (Tx) recipients. The organs displaying DGF (n=48) had a significantly higher degree of glomerular sclerosis and tubular atrophy (P<0.01), as well as of interstitial fibrosis and vascular damage (P<0.02) in time-zero biopsies. In patients who received an "ideal" organ for Tx (total histological score < or = 4), DGF showed a strong relationship with Deltaage D-R (70% increase of risk for donors 10 years older than recipients), and with the histological score (odds ratio 1.34). In contrast, donor hypertension was the most relevant variable independently associated with DGF (odds ratio 19.4) in patients receiving a suboptimal organ (histological score >4). Moreover, DGF and donor hypertension adversely affected graft function at 1 year, but only in Tx patients with a histological score >4 in time-zero biopsy. Of note, both patients with and those without DGF showed a very low incidence of biopsy-proven acute rejection (8.5 and 6.8%, respectively) and a rather short cold ischemia time (<16 hr). Our findings suggest that the quality of the transplanted organ and the occurrence of DGF are strictly related to each other and can influence graft function through apparently nonimmune mechanisms. In addition, long-standing donor hypertension is a strong independent variable affecting both DGF and graft function of suboptimal cadaveric kidneys, at least up to 1 year.

Achados histológicos em 48 pacientes transplantados do fígado: biópsias do enxerto pós-reperfusão (tempo zero) e de três a 15 dias pós-transplante

Introducao: As relacoes entre a morfologia do enxerto transplantado e a do periodo pos-transplante sao importantes no acompanhamento dos pacientes e no direcionamento dos tratamentos instituidos. Objetivo: Analisar os achados histologicos do enxerto hepatico em biopsiasrealizadas pos-reperfusao (tempo zero) e naquelas realizadas de tres a 15 dias pos-transplante. Materiais e metodos: Noventa e seis biopsias de 48 pacientes foram selecionadas por terem sido colhidas no tempo zero (pos-reperfusao) e no periodo compreendido entre o terceiro e o 15o dia pos-transplante, com identificacao das lesoes hepatocitarias degenerativas, necrose e atividadeinflamatoria. As biopsias pos-transplante foram ainda graduadas quanto ao indice de atividade de rejeicao (IAR), segundo o consenso de Banff. Resultados: Osachados histopatologicos mais frequentes nas biopsias pos-reperfusao foram de degeneracao hidropica discreta (acometimento de ate 50% dos hepatocitos) em 87,5% dos casos e necrose focal intralobular (litica, apoptose) presente em 75% dos pacientes, em graus variaveis. Nas biopsiasrealizadas pos-transplante encontrou-se degeneracao hidropica discreta tambem em 87,5% dos casos e rejeicao aguda em 38 (79,2%) pacientes. Nestas biopsias com rejeicao aguda, chamou atencao a intensidade da agressao a ductos biliares em graus moderado (2) e acentuado (3) presentes em 42,1% dos casos, enquanto a endotelialite portal, nestas mesmas intensidades, ocorreu em 21,05%. Conclusao: Nossos dados evidenciaram lesoes relacionadas a preservacao (lesoes do tipo harvesting) nas biopsias pos-reperfusao. As biopsias pos-transplante revelaram indice de rejeicao morfologica na maioria dos casos, como evidenciado na literatura, destacando-se aqui a intensidade da agressao a ductos biliares.

Apoptotic hepatocytes in rejection and vascular occlusion in liver allograft specimens

Programmed cell death (apoptosis) has been described in different hepatobiliary diseases and in immune-mediated cytotoxicity. Apoptosis of hepatocytes and bile duct epithelial cells was detected in chronic liver allograft rejection. In severe acute rejection a DNA fragmentation in-situ assay showed positivity of apoptotic cells and centrilobular necrosis. Although apoptosis is triggered by ischaemia, the potential role of apoptosis in tissue damage caused by hepatic vascular occlusion after orthotopic liver transplantation has not yet been investigated. We examined biopsies for apoptotic cell death in 50 liver allografts: 29 with acute liver rejection, six without rejection, five time-zero biopsies, and 10 cases with hepatic artery thrombosis. In addition to a semiquantitative assessment of apoptotic bodies in haematoxylin and eosin stains, an in-situ end nick-labelling technique (TUNEL) was used to detect DNA fragmentation. In all cases with hepatic artery thrombosis the incidence of apoptosis was found significantly increased in comparison to acute rejection. As apoptosis is a mechanism in the early stages of tissue damage prior to necrosis, increased apoptosis in liver allograft biopsies might be regarded as a signal of early ischaemia indicating initial vascular occlusion.