Preimplantation Biopsy Research Articles

Multi-photon microscopy for the evaluation of interstitial fibrosis in extended criteria donor kidneys: A proof-of-concept study.

To evaluate the initial use of label-free second harmonic generation (SHG) imaging with two-photon excitation (2PE) auto-fluorescence in multiphoton microscopy (MPM) for the quantification of collagen/fibrosis on preimplantation biopsies of extended criteria donors (ECD). Twenty preimplantation core biopsies were extracted from 10 donor kidney samples, of which originated from seven donors. Kidney Donor Profile Index (KDPI) and Remuzzi scores of biopsies were calculated. Collagen parameters measured included quantification by the Collagen Area Ratio in Total Tissue (CART) and qualitative measurements by Collagen Reticulation Index (CRI). Biopsies classified with>85% KDPI scores had significantly higher CART (p=.011) and lower CRI values (p=.025) than biopsies with ≤ 85% KDPI scores. Increase in CRI values correlated significantly with rise in recipient creatinine levels 1-year post-transplant (p=.027; 95% CI: 4.635-66.797). MPM is an evolving technology that enables the quantification of the amount (CART) and quality (CRI) of collagen deposition in unstained preimplantation biopsies of donor kidneys stratified by KDPI scores. This initial evaluation found significant differences in both parameters between donor kidneys with more or less than 85% KDPI.

Successful kidney transplantation from a deceased donor with severe COVID-19 respiratory illness with undetectable SARS-CoV-2 in donor kidney and aorta

To the Editor: Kidney transplantation (KT) from coronavirus disease 2019 (COVID-19) donors were avoided due to concerns for donor-derived transmission.1Kates OS Fisher CE Rakita RM Reyes JD Limaye AP. Use of SARS-CoV-2-infected deceased organ donors: should we always "just say no?".Am J Transplant. 2020; 20 (doi:10.1111/ajt.16000): 1787-1794Crossref PubMed Scopus (0) Google Scholar,2Shah MB Lynch RJ El-Haddad H Doby B Brockmeier D Goldberg DS. Utilization of deceased donors during a pandemic: argument against using SARS-CoV-2-positive donors.Am J Transplant. 2020; 20 (doi:10.1111/ajt.15969): 1795-1799Crossref PubMed Scopus (43) Google Scholar There have been no data on the long-term safety, and sensitive molecular testing for SARS-CoV-2 in donor kidney is not routinely performed. We report a successful KT from a deceased donor who died with severe COVID-19 respiratory failure with a detailed investigation of the donor kidney and aorta tissue for SARS-CoV-2. A 30-year-old female was admitted to a hospital due to severe COVID-19 pneumonia with a positive nasopharyngeal RT-PCR for SARS-CoV-2. With clinical worsening, she was placed on extracorporeal membrane oxygenation, but developed hypoxic brain injury and progressed to brain death. Renal function was stable during her hospital course with a serum creatinine concentration of 0.7 mg/dl. SARS-CoV-2 PCR for bronchoalveolar lavage and nasopharyngeal swab re-tested 3 days prior to donation was negative. A 55-year-old male recipient with an end-stage renal disease secondary to hypertension underwent a transplant with the left kidney from this donor. The donor kidney was studied using pre-implantation surgical biopsy samples to investigate the presence of SARS-CoV-2 RNA using in situ hybridization (ISH) and quantitative RT-PCR (qRT-PCR). Aorta tissue dissected with the kidney during the organ procurement was also studied given high expression of angiotensin-converting enzyme 2 receptors in vasculature. Kidney hematoxylin and eosin staining showed acute tubular injury without any glomerular damage or inflammation (Figure 1A). ISH analyses lacked a positive signal for SARS-CoV-2 RNA in the donor kidney sample (Figure 1B) compared to the SARS-CoV-2 positive lung control (Figure 1C). All samples for qRT-PCR were negative for SARS-CoV-2. We found no evidence of SARS-CoV-2 in donor tissues. The recipient has tested negative for SARS-CoV-2 by nasopharyngeal swab RT-PCR on days 20, 30, and 90 following transplantation, and there have been no signs or symptoms of COVID-19. After an initial period of delayed graft function requiring hemodialysis, the recipient now has excellent renal recovery over 9 months following the transplant, and the most recent creatinine is 1.3 mg/dl. Evidence supporting the use of deceased donors who died due to catastrophic COVID-19-related respiratory illness is limited, and these cases do not fit in any categories of the most up-to-date guideline for COVID-19 donors.3Summary of current evidence and information–donor SARS-CoV-2 testing & organ recovery from donors with a history of COVID-19. https://optn.transplant.hrsa.gov/media/kkhnlwah/sars-cov-2-summary-of-evidence.pdf. Published September 22, 2021. Accessed December 20, 2021.Google Scholar As such, the decision of whether to accept nonlung organs from those donors has been decided on a case-by-case basis. Based on recent observations of successful KT outcomes from mild or asymptomatic SARS-CoV-2 positive donors,4Koval CE Poggio ED Lin YC Kerr H Eltemamy M Wee A. Early success transplanting kidneys from donors with new SARS-CoV-2 RNA positivity: a report of 10 cases.Am J Transplant. 2021; 21 (doi:10.1111/ajt.16765): 3743-3749Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar and a short-term safety report of KT from a donor similar to this case,5Meshram HS Kute VB Patel H Desai S Chauhan S Dave RB. A case report of successful kidney transplantation from a deceased donor with terminal COVID-19-related lung damage: ongoing dilemma between discarding and accepting organs in COVID-19 era!.Transpl Infect Dis. 2021; 23 (doi:10.1111/tid.13683)Crossref Scopus (10) Google Scholar the transmission risk of SARS-CoV-2 through KT is likely very low. In conclusion, the use of deceased donors who died after severe COVID-19 can be individually considered for KT, and these organs should not be routinely discarded. We acknowledge that our case may not be representative of many possible COVID-19 donors since the donor was negative for SARS-CoV-2 PCR at the time of transplantation. Larger scale studies are warranted to confirm our findings, and long-term graft outcomes from COVID-19 donors should be studied. We thank all the JH kidney transplant and COVID-19 research team members.

Perfusate Metabolomics Content and Expression of Tubular Transporters During Human Kidney Graft Preservation by Hypothermic Machine Perfusion.

Ischemia-related injury during the preimplantation period impacts kidney graft outcome. Evaluating these lesions by a noninvasive approach before transplantation could help us to understand graft injury mechanisms and identify potential biomarkers predictive of graft outcomes. This study aims to determine the metabolomic content of graft perfusion fluids and its dependence on preservation time and to explore whether tubular transporters are possibly involved in metabolomics variations. Kidneys were stored on hypothermic perfusion machines. We evaluated the metabolomic profiles of perfusion fluids (n = 35) using liquid chromatography coupled with tandem mass spectrometry and studied the transcriptional expression of tubular transporters on preimplantation biopsies (n = 26), both collected at the end of graft perfusion. We used univariate and multivariate analyses to assess the impact of perfusion time on these parameters and their relationship with graft outcome. Seventy-two metabolites were found in preservation fluids at the end of perfusion, of which 40% were already present in the native conservation solution. We observed an increase of 23 metabolites with a longer perfusion time and a decrease of 8. The predictive model for time-dependent variation of metabolomics content showed good performance (R 2 = 76%, Q 2 = 54%, accuracy = 41%, and permutation test significant). Perfusion time did not affect the mRNA expression of transporters. We found no correlation between metabolomics and transporters expression. Neither the metabolomics content nor transporter expression was predictive of graft outcome. Our results call for further studies, focusing on both intra- and extratissue metabolome, to investigate whether transporter alterations can explain the variations observed in the preimplantation period.

High soluble HLA-DQB2 levels in posttransplant serum are associated with kidney graft dysfunction.

HLA-DQB2 is a gene of limited polymorphism, with unknown function that presents at least two transcript variants: v1, which encodes the full-length beta-chain, and v2, which lacks exon 4 and could give rise to a soluble protein. We previously showed a strong correlation between high v2 expression in preimplantation biopsies (PIB) of kidneys from young (18- to 49-year olds) but not from old, deceased donors and 1-year posttransplant low (estimated glomerular filtration rate<45ml/min/1.73 m2 ) graft function (GF). In this study, we aimed to investigate the impact of posttransplant soluble HLA-DQB2 (sDQB2) serum levels, v1 expression in PIB, and recipient HLA-DQB2 rs7453920 A/G polymorphism on GF. sDQB2 was evaluated by enzyme-linked immunosorbent assay in sera from 114 recipients, collected at least 1 year (median 2.1 years) after transplantation. Higher sDQB2 levels were observed in recipients of kidneys from young, but not from old, donors that had a ≥30% decline in GF within 1 year after blood collection for sDQB2 determination. Among the 15 recipients of kidneys from young donors with sDQB2 ≥ 1.52ng/ml, 40% presented a ≥30% decline in GF, whereas this occurred in none of the 43 recipients with lower sDQB2 levels (p=0.007; OR: 36.5). Expression of HLA-DQB2 variant 1, measured by reverse transcription-polymerase chain reaction (RT-PCR) in 92 PIB from young or old donors, did not significantly differ between transplants with high or low 4-year GF. HLA-DQB2 rs7453920 single nucleotide polymorphism (SNP) frequencies did not significantly differ between recipients with low or high 4-year GF. We conclude that HLA-DQB2 variant 1 expression in PIB and recipient rs7453920 SNP polymorphism are not associated with graft outcome. On the other hand, the association, in transplants of kidneys from young donors, between high posttransplant serum sDQB2 levels and decline in GF is a very interesting finding that deserves a validation study in a larger cohort.

Long-standing donor diabetes and pathologic findings are associated with shorter allograft survival in recipients of kidney transplants from diabetic donors

Approximately 6% of deceased kidney donors (DKDs) are diabetic; their kidneys may be associated with worse allograft survival, but published studies suggest that recipient diabetes status has a greater impact on mortality and survival. Since biopsy findings are the most common reason for organ discard, we sought to understand histologic and clinical factors that influence graft survival in patients who receive a kidney from a diabetic DKD. We retrospectively reviewed our institutional experience from 2005 to 2019, and re-evaluated pre-implantation and earliest post-transplant biopsies. Histologic findings were compared against a control cohort of non-diabetic DKD. Of 829 adult DKD transplants, 37 (4.5%) came from diabetic donors. There was no significant difference in diabetic vs. non-diabetic DKD graft survival for all-comers; however, when stratified by duration of donor diabetes, donor diabetes ≥6 years was associated with graft failure. In 25 patients with post-transplant biopsies available, diabetic DKD allografts had significantly greater non-glomerular chronic injury than non-diabetic DKD allografts. Moderate arteriolar hyalinosis (in 24%), moderate tubular atrophy and interstitial fibrosis (IFTA, in 36%), and diabetic glomerulopathy (in 24%) on early post-transplant biopsy were associated with allograft failure. Pre-implantation frozen section discrepancies were more common in long-standing donor diabetes, and arteriolar hyalinosis and IFTA scores on frozen accurately prognosticated graft loss. There was no morphologic improvement in lesions of diabetic nephropathy on short-term follow-up. In conclusion, donor diabetes ≥6 years, and histologic findings on frozen section and early post-transplant biopsy are associated with diabetic DKD allograft loss.

Impact of the explanting surgeon's impression of donor arteriosclerosis on outcome of kidney transplantations from donors aged ≥65 years.

Careful donor selection is important for kidney transplantations (KT) from suboptimal donors aged ≥65 years. Several tools such as histopathological assessment of preimplant biopsies have been shown to predict allograft survival and can be applied for selection. Whether the explanting surgeon's appraisal is associated with outcomes of KTs from suboptimal donors is unknown. We compared outcomes of KTs from ≥65-year-old deceased donors performed at our centre between 1999 and 2018 for which grading of macroscopic 'donor arteriosclerosis' (n=104) and 'organ quality' (n=208) as judged by the explanting surgeon and documented on the Eurotransplant kidney organ report was available. No association was observed between degree of macroscopic donor arteriosclerosis and death-censored graft survival in univariable or multivariable regression analyses. Compared to KTs from donors with no/mild arteriosclerosis, KTs from donors with moderate/severe arteriosclerosis were associated with a significantly impaired allograft function 3 months, 1 year and 3 years after transplantation (e.g. at 3 years: 176.8 µmol/l vs 137.0 µmol/l, P=0.003). Following multivariable regression analysis, these differences remained significant at 3 months and 3 years after KT. No association was observed between degree of macroscopic arteriosclerosis and mortality or primary non-function as well as no consistent association with delayed graft function and histological arteriosclerosis. Assessment of 'organ quality' was not associated with outcomes. Our data suggest that the explanting surgeon's assessment of donor arteriosclerosis is associated with allograft function. Larger studies and better standardization of kidney inspection after explantation are required to further explore the impact of surgeon's appraisal in KT.

Aggravation of fibrin deposition and microthrombus formation within the graft during kidney transplantation

In kidney transplantation, microthrombi and fibrin deposition may lead to local perfusion disorders and subsequently poor initial graft function. Microthrombi are often regarded as donor-derived. However, the incidence, time of development, and potential difference between living donor kidneys (LDK) and deceased donor kidneys(DDK), remains unclear. Two open-needle biopsies, taken at preimplantation and after reperfusion, were obtained from 17 LDK and 28 DDK transplanted between 2005 and 2008. Paraffin-embedded sections were immunohistochemically stained with anti-fibrinogen antibody. Fibrin deposition intensity in peritubular capillaries(PTC) and glomeruli was categorized as negative, weak, moderate or strong and the number of microthrombi/mm2 was quantified. Reperfusion biopsies showed more fibrin deposition (20% to 100% moderate/strong, p < 0.001) and more microthrombi/mm2 (0.97 ± 1.12 vs. 0.28 ± 0.53, p < 0.01) than preimplantation biopsies. In addition, more microthrombi/mm2 (0.38 ± 0.61 vs. 0.09 ± 0.22, p = 0.02) and stronger fibrin intensity in glomeruli (28% vs. 0%, p < 0.01) and PTC (14% vs. 0%, p = 0.02) were observed in preimplantation DDK than LDK biopsies. After reperfusion, microthrombi/mm2 were comparable (p = 0.23) for LDK (0.09 ± 0.22 to 0.76 ± 0.49, p = 0.03) and DDK (0.38 ± 0.61 to 0.90 ± 1.11, p = 0.07). Upon reperfusion, there is an aggravation of microthrombus formation and fibrin deposition within the graft. The prominent increase of microthrombi in LDK indicates that they are not merely donor-derived.

Retrieved but not transplanted kidneys: how to limit the losses? A retrospective national study.

Despite the organ shortage, a significant number of deceased donor kidneys are retrieved but not transplanted (RNTK). This study aims to describe and analyze the main causes of potential grafts discard and to propose adequate solutions. We collected data from the Cristal database of the French Biomedicine Agency about RNTK over one year. Expert opinion was taken from urologists with extensive expertise in renal transplantation. They retrospectively analyzed each record to assess the appropriateness of each graft refusal and subsequent kidney discard. Of 252 kidneys were retrieved but not transplanted in France over one year. The main reasons for discard were vascular abnormalities in 43.7% (n=110), suspicion of malignant tumor in 18.7% (n=47), and severe histological lesions on preimplantation biopsy in 12.3% (n=31). The reason for kidney refusal was undetermined in 4.8% (n=12). Iatrogenic lesions were responsible for 26.2% (n=66). Overall, 46.0% (n=16) and 25.0% (n=63) of the grafts were, respectively, properly and improperly denied, and the analysis was not possible in 29.0% (n=73). In total, 36.9% of RNTK could have been transplanted. Reduction of iatrogenic lesions, improvement of microsurgical repair skills, and proper histological examination are necessary to reduce the number of RNTK. A prospective study applying the proposed principles is undoubtedly essential to complete this work.

Correlation of Chronic Histologic Changes on Preimplantation Frozen Section Biopsy With Transplant Outcomes After Deceased Donor Kidney Transplantation.

It is unclear if preimplantation frozen section biopsy correlates with outcomes after deceased donor kidney transplantation. To assess if chronic histologic changes on the preimplant frozen section correlates with graft loss and estimated glomerular filtration rate independently of kidney donor profile index (KDPI). Seven hundred three preimplantation biopsies were reviewed and a Banff sum score was calculated using glomerular sclerosis, interstitial fibrosis, vascular intimal thickening, and arteriolar hyalinosis. The posttransplant outcomes were compared for preimplantation biopsy Banff sum 0-1, 2-3, and 4-9. The cohort was also stratified by KDPI 85 or less versus more than 85. For the entire biopsy cohort, graft survival, estimated glomerular filtration rate at 1 year, and chronic changes on a 1-year posttransplant biopsy were superior in the group with preimplantation Banff sum 0-1. After stratifying by KDPI, the Banff sum no longer correlated with graft survival. In a univariate mode, using the Banff sum score as a continuous variable, a higher Banff sum score was significantly associated with graft failure (P = .03); however, after adjusting the KDPI, the Banff sum score no longer correlated with graft failure (P = .45). The 1-year estimated glomerular filtration rate and 1-year biopsy changes were superior in the group with Banff sum 0-1 only in the cohort with KDPI 85 or less. In donor kidneys used for transplant, preimplantation biopsy chronic changes correlate with estimated glomerular filtration rate and biopsy findings at 1 year, but biopsies with mostly mild chronicity and Banff sum scores less than or equal to 5 did not impact graft survival beyond KDPI.

MO973PRE-IMPLANTATION BIOPSY FINDINGS AND IMPACT ON LIVE DONOR KIDNEY TRANSPLANT RECIPIENT OUTCOMES - A SINGLE CENTRE STUDY

Abstract Background and Aims Live donor kidney transplantation remains the mainstay of renal replacement therapy in Sri Lanka. The basic universal pre surgical investigations, human leucocyte antigen (HLA) matching and cross matching are routinely performed, however due to high rates chronic kidney disease (CKD) as well as increasing numbers of, chronic kidney disease unknown etiology (CKDu) in Sri Lanka, there is a possibility of subclinical kidney disease being present in donor kidneys which go undiagnosed. A study of pre-implantation biopsy along with follow-up outcomes of kidney transplant recipients is conducted to identify presence of subclinical kidney disease in a Sri Lankan cohort of patients. Method We collected thirty three (33) live donor pre-implantation biopsies during 4 consecutive months in 2020 as well as 1 month follow-up data. This is part of an ongoing follow-up study which is conducted at National Hospital, Kandy, Sri Lanka. Results Thirty three (33) live donor recipients and their pre-implantation renal biopsy samples were studied. The mean age of the study participants’ was 37.6 (SD 12.5, range 13 - 59) years. A predominant number of male patients were in the sample (n=21, 63.6%). Underlying aetiology of end stage renal disease (ESRD), was predominantly due to chronic hypertension (39.3%; n=13) and diabetic kidney disease (21.2%, n=7) accounting for nearly 60% of the study participants. Among the 33 live donors 1st degree, 2nd degree and non-relative donors were 54.4% (n=18), 18.2% (n=6) and 27.3% (n=9) respectively. Pre-implantation renal biopsy results reported 36.4% (n=12) with abnormal biopsy findings including chronic interstitial nephritis (n=4, 12.1%), interstitial fibrosis (n=6, 18.18%) and acute tubular necrosis (n=2, 6%). Follow-up revealed delayed graft function occurring in 18.2% (n=6) of recipients with 50% (n=3) of them showing abnormalities in the pre-operative donor biopsy sample. At one month follow-up, 48.5% (n=16) reported complications which included graft failure 3% (n=1), all-cause mortality 3% (n=1), acute rejection 39.4% (n=13) and infections 24.2% (n=8). Overall, 37.5% (n=6) of these recipients had abnormal donor biopsy findings, however no significant statistical association was identified. Conclusion Our study identified subclinical kidney disease in donor kidneys despite standard pre-transplant screening. Even though, statistically not significant, recipients with abnormal pre-implantation biopsy findings had adverse short term post-transplant complications.

MO089HISTOMORPHOMETRIC ANALYSIS OF GLOMERULI AND CAPILLARIES DENSITY IN THE INTERSTITIUM IN PREIMPLANTATION NEEDLE BIOPSIES OF PAIRED KIDNEYS HARVESTED FROM ADULT CADAVERIC DONORS

Abstract Background and Aims Preimplantation needle biopsy of kidney allows more precise interpretation of subsequent kidney biopsies performed after transplantation and potentially also may predict kidney graft survival. It is unknown, whether it is justified to perform the biopsy of one kidney only and then to transmit obtained results also to the second kidney or biopsies of both kidneys are mandatory. The aim of the study was to assess differences regarding glomerular volume, glomerular density and capillary density in the interstitium of both kidneys harvested from the same deceased donor. Method The study involved 40 pairs of kidneys (all together 80 kidneys) in which preimplantation kidney biopsies were performed. Kidneys were harvested from 40 deceased donors (17 females and 23 males; mean age 42.3 [37.6-47.0] years old) died because of intracranial haemorrhage (17 donors) or cerebral trauma due to accident (23 donors). Histomorphometric analysis was performed using “Olympus BX51” microscope (Olympus, Tokyo, Japan) coupled with “Olympus BX50” camera and the “cellSens Standard” software (Olympus, Tokyo, Japan). Weibel-Gomez formula was adapted to calculate glomerular volume. Results No significant differences were found between mean kidneys length [115.8 (112.4-119.1) vs.115.5 (112.5-118.5) mm], glomerular volume [2.59 (2.24-2.93) vs 2.49 (2.15-2.84) μm3 x106 ], glomerular density [3.43 (3.07-3.80) vs 3.24 (2.87-3.61) n/mm2] and interstitial capillaries density [233.58 (211.26) vs 217.80 (199.45-236.47) n/mm2] of both kidneys harvested from the same deceased donor. Conclusions 1. Both kidneys harvested from the same deceased donor did not differ significantly in kidney length, glomerular volume, glomerular density and capillary density. 2. Our results justify to preimplantation biopsy of only one kidney and the results from the histomorphometric analysis may be used in the future also for assessment of the second kidney.

Renal Resistance Trend During Hypothermic Machine Perfusion Correlates With Preimplantation Biopsy Score in Transplantation of Kidneys From Extended Criteria Donors

Graft quality from extended criteria donors (ECDs) is extremely wide, and a reliable evaluation parameter is required. So far, biopsy is widely used to evaluate ECD organs and to decide whether double (DKT) or single (SKT) kidney transplantation should be performed. The aim of this study is to compare renal resistance (RR) trend during hypothermic machine perfusion (HMP) with a preimplantation biopsy score. From December 2014 to April 2020, HMP has been systematically applied to all organs from ECDs for at least 3 hours. All grafts underwent a preimplantation biopsy histologic assessment with Karpinski's score. SKTs or DKTs were performed accordingly. RR trend during the first 180 minutes of HMP was compared with the biopsy score. Eighty-three kidneys were used to perform 57 transplantations (31 SKTs and 26 DKTs). A biopsy confirmed suitability for transplantation in all cases, and the median score was 4 (range, 2-7). Kidneys with a score of 5 to 7 had significantly higher RR value than kidneys with a score of 0 to 4 at basal time (3.35 vs 2.71; P=.074), at 60 minutes (1.24 vs 0.94; P=.031), at 120 minutes (1.10 vs 0.81; P=.010), and at 180 minutes (1.00 vs 0.77; P=.022). A cutoff value of RR ≥0.88 at 120 minutes of perfusion had the best sensibility and specificity (0.71 and 0.75, respectively) to discriminate kidneys with a score of 5 to 7 from kidneys with a score of 0 to 4. No differences were found in postoperative outcomes between SKT and DKT recipients. RR trend during HMP correlates with the histologic score in ECD kidneys and can be used as a reliable parameter to evaluate graft quality.

POS-722 SPECTRUM OF RENAL ALLOGRAFT BIOPSY – A SINGLE CENTRE EXPERIENCE

Histopathology plays a key role in diagnosis of graft dysfunction in transplant recipients. Apart from graft rejection, many patients are having recurrence of native kidney disease and infections causing graft dysfunction. In this study, we would like to describe the different histopathological profile of transplant kidney biopsy in our centre. We had conducted a retrospective descriptive study of all transplant kidney biopsies which were performed between Jan 2014 to Nov 2020 in a tertiary care hospital. From the registry, age, sex, duration since transplant and histopathological diagnosis were collected and analysed. Total number of biopsies performed were 587 in the past seven years. Males were 81.3% (n=477). Patients with age less than 20 were 4.9% (n=29), 21 to 40 years were 75.2% (n=441) and 41 to 60 years were 19.9% (n=117). None of them were more than 60 years of age. Duration since transplant was analysed for these biopsies. Patients with less than 1 month, 1month to 3 months, 3 months to 1 year and more than 1 year were 180 (30.6%), 92 (15.7%), 120 (20.4%) and 195 (33.2%) respectively. Due to the presence of multiple pathologies in a biopsy, a total of 649 pathologies were found. Cellular and humoral rejections were 32.2% and 13.6% respectively. Across these timelines since transplant, cell mediated rejections (CMR) (34.5%, n=72) and antibody mediated rejections (ABMR) (50%, n=44) were more seen during >1 year post transplant. Apart from these, incidence of glomerular, interstitial and vascular pathologies found which were described in table 1 below. IgA Nephropathy and Thrombotic Microangiopathy (TMA) were most seen glomerular pathology (n=19,2.9%) followed by Focal segmental glomerulosclerosis (FSGS) (n=17,2.6%). Crescentic IgA Nephropathy was seen in 2 patients who had IgA Nephropathy as native kidney disease. 2,8-Dihydroxy Adenine Crystalline (DHA) Nephropathy was diagnoed at 10 months post transplant in one patient whose native kidney disease was not known. Out of 587 biopsies, 9 were preimplantation and 12 were followup protocol biopsies. In the preimplantation biopsy, 6 were normal and 3 were Acute Tubular Injury (ATI). Special stains for SV 40 and CMV were used in 14 and 2 patients respectively. Two patients had SV 40 and one had CMV positivity among them. Electron microscopy was done in 6 patients. Four of them had diffuse effacement of podocyte foot processes whereas, in light microscopy 3 had minimal change pattern of injury and one had FSGS. One had subepithelial and mesangial electron dense deposits with Membranoproliferative Glomerulonephritis(MPGN) in light microsopy and the other had mesangial electron dense deposits / effacement of foot processes of podocyte with IgA Nephropathy / Collapsing Glomerulopathy in light microscopy. Complications encountered post biopsy were perinephric hematoma and hematuria. One patient with perinephric hematoma had blood clots passed in urine which caused hydroureteronephrosis and then resolved with conservative management. In our series, CNI Toxicity was seen in 26.8% (n=174), Infection in 4.2% (n=27), Rejection in 46.8% (n=304), Glomerulonephritis in 12.2% (n=79) and other pathologies in 10% (n=65) of the allograft biopsies performed.

L’insuffisance rénale aiguë du donneur en mort encéphalique : une réelle contre-indication à la transplantation rénale ?

The shortage of kidney transplants encourages the expansion of the limits of eligibility criteria for donation. Many donors who are brain dead display acute renal failure at the time of death; is this a real contraindication to harvesting? The aim of this study was to assess kidney graft survival from donors after brain death with confirmed acute renal failure, with or without anuria previous donation. All of the transplants performed in two university hospitals between 2010and 2017were analyzed retrospectively. All patients who underwent single kidney transplant from a brain-dead donor with acute renal failure (ARF) were included in this study. ARI was defined here by a decrease over 50% of glomerular filtration rate (GFR) to a threshold below 45mL/min/1.73m2at the time of kidney procurement. Kidney graft survival, incidence of delayed graft function (DGF) and the GFR at 12months were analyzed. Analysis of kidney transplant survival based on pre-implantation biopsies was additionally done. One hundred and sixty four patients were transplanted with a kidney from donor with ARF during the selected period. At the admission in ICU the average GFR was 67,7±19mL/min/1,73m2. At the time of donation, the average age of donors was 56.4±17.7years, the GFR was 33.7±8.0mL/min/1.73m2 16% of donors were anuric. Cold ischemia time (CIT) was 16.8±5.0hours. The average age of recipients was 55.6±14.1years. 81% of the cases were primary transplants. Graft function took place within 7.8±9.4days after transplantation. There were two non-primary functions (PNF). One hundred and fifty two patients (93%) had a functional graft at 12months. The mean GFR at 12months was 46.8±20.1mL/min/1.73m2and 122patients (73%) had a GFR greater than 30mL/min/1.73m2. Seventy-one percent of preimplantation biopsies revealed acute tubular necrosis (ATU); no cortical necrosis was observed. Survival of theses grafts was 85%, comparable to the total population of study (P=0,21) CONCLUSION: The acute renal failure of the brain-dead donor should not alone be systematically a contraindication to harvesting and kidney transplantation.

Exploring the role of the complement system, endothelial injury, and microRNAs in thrombotic microangiopathy after kidney transplantation.

ObjectiveWe investigated whether the recipient’s complement system function, kidney graft endothelial ultrastructural injury, and microRNA (miRNA) expression before transplantation may be associated with the risk of posttransplant de novo thrombotic microangiopathy (TMA).MethodsComplement system function assessment, histological and ultrastructural examination of preimplantation and kidney graft biopsies, and microRNA assessment were performed on kidney transplant recipients (KTRs) with de novo TMA.ResultsOn the basis of the clinical course, histological findings, and miRNA patterns, the following two de novo TMA phenotypes were observed: a self-limiting disease that was localized to the kidney graft and a systemic disease that progressed to graft failure without timely treatment. Decreased alternative complement pathway activity and ultrastructural endothelial injury before transplantation were confirmed in all five KTRs and four of five KTRs, respectively, but they did not correlate with de novo TMA severity.ConclusionsAlternative complement pathway abnormalities in KTRs and endothelial ultrastructural injury on preimplantation biopsy might be associated with de novo posttransplant TMA, although they did not predict posttransplant TMA severity (localized vs. systemic). The specific miRNA expression patterns in preimplantation kidney graft biopsies demonstrated a borderline statistically significant difference and might provide more accurate information on posttransplant TMA severity.

From Inflammation to the Onset of Fibrosis through A2A Receptors in Kidneys from Deceased Donors.

Pretransplant graft inflammation could be involved in the worse prognosis of deceased donor (DD) kidney transplants. A2A adenosine receptor (A2AR) can stimulate anti-inflammatory M2 macrophages, leading to fibrosis if injury and inflammation persist. Pre-implantation biopsies of kidney donors (47 DD and 21 living donors (LD)) were used to analyze expression levels and activated intracellular pathways related to inflammatory and pro-fibrotic processes. A2AR expression and PKA pathway were enhanced in DD kidneys. A2AR gene expression correlated with TGF-β1 and other profibrotic markers, as well as CD163, C/EBPβ, and Col1A1, which are highly expressed in DD kidneys. TNF-α mRNA levels correlated with profibrotic and anti-inflammatory factors such as TGF-β1 and A2AR. Experiments with THP-1 cells point to the involvement of the TNF-α/NF-κB pathway in the up-regulation of A2AR, which induces the M2 phenotype increasing CD163 and TGF-β1 expression. In DD kidneys, the TNF-α/NF-κB pathway could be involved in the increase of A2AR expression, which would activate the PKA–CREB axis, inducing the macrophage M2 phenotype, TGF-β1 production, and ultimately, fibrosis. Thus, in inflamed DD kidneys, an increase in A2AR expression is associated with the onset of fibrosis, which may contribute to graft dysfunction and prognostic differences between DD and LD transplants.

Donneurs très âgés en transplantation rénale : jusqu’où peut-on aller ?

In order to increase the pool of organ donors, kidney transplantation from very old-donors, notably aged more than 70, is increasing. Compared to the United States, where the use of these grafts does not reach 5%, in France it reaches over 20%. Kidney aging is determined by a progressive glomerusclerosis, interstitial fibrosis, and nephrosclerosis, responsible of a linear decrease of glomerular filtration rate with time. Aging in kidney transplantation goes along also with an increased immunogenicity and risk of ischemia-reperfusion injuries. Hence, the prognosis of these transplantations is worse than those from younger donors, even though it remains better than dialysis. Data is lacking on risk factors of graft loss in this specific population. Hypothermic perfusion machine, pre-implantation kidney biopsy, dual kidney transplantation and immunosuppressive strategies have been evaluated to improve the long-term prognosis of these grafts.

Expanding the Utilization of Kidneys from Donors with Acute Kidney Injury

Our aim is to review the experience with transplanting kidneys from decreased donors with acute kidney injury (AKI). The discard rate is higher for kidneys from AKI donors. Studies have uniformly shown that the risk of delayed graft function (DGF) is higher. However, the majority of studies have shown that other outcomes including short and long graft survival, eGFR, and risk of rejection are not inferior with transplanting AKI donor kidneys. To select AKI donor kidneys, we depend on preimplantation biopsy to exclude AKI kidneys with > 10% cortical necrosis or more than mild chronic changes. Although the DGF rate is higher, we have been able to safely discharge patients by POD 2 and manage DGF as an outpatient. It is estimated that if the transplant community used appropriately selected kidneys from AKI donors, there would be almost 600 additional transplants done each year in the US.

P1683INFLUENCE OF BIOPSY PROGNOSIS ON GRAFT SURVIVAL

Abstract Background and Aims Renal transplantation is the best alternative renal replacement option for patients with advanced chronic kidney disease. However, the supply of young donors is limited, and does not cover the demand of patients on the renal transplant waiting list, for this reason are being used older donors and exists a high discard rate of those organs base on pathological results (score) of the preimplant renal biopsy. There are several methods to evaluate the quality of the kidneys and the Kidney Donor Profile Index (KDPI) has acquired special relevance to decide the perform of preimplant renal biopsy. Based on the score, a preimplant renal biopsy is performed, which is decisive in certain cases. However, there is poor evidence to support this decision, which can be described as “conservative,” since there is not enough certainty that there is influence of the preimplant biopsy score score on graft survival. Method 389 biopsies of kidney transplant donors of cadaver donors in brain death and asystole type III were included. Donors in asystole type II, combined and live, were excluded. Samples examined by the same pathologist and in paraffin (no case by freezing). A graft survival analysis was performed based on the results of the renal biopsy (score). Likewise, a multivariate analysis of graft survival was carried out including, in addition to the results of the renal biopsy, results such as the age of the donor and recipient and the KDPI. Results graft survival was compared between two transplant subpopulations in our hospital based on whether a preimplant biopsy was performed. According to the data used there are no significant differences in graft survival between transplants in which biopsy has been performed and those that have not. Conclusion our work shows, as is currently the case in the literature, the absence of influence on the score of the preimplant biopsy score on graft survival.

Donor Age and Ischemia Time Are Independent Factors Affecting Graft Survival after En Bloc Kidney Transplantation from Donors Less than Three Years of Age

This study aimed to investigate the outcomes of transplantation from donors aged less than three years in a single-center consecutive series. A total of 52 en bloc kidney graft transplantations were performed. In 22 cases, organs were procured from donors aged less than one year (group 1). In 30 cases, the age of donors varied from one to three years (group 2). After transplantation, renal function and graft and patient survival were evaluated retrospectively. No significant difference was observed between the groups regarding recipient age, time on dialysis, ischemia time, human leukocyte antigen matching, the time needed to reach serum creatinine levels of ≤2 mg/mL, and patient survival. Eight grafts were lost during the first six months after grafting in group 1, whereas only two grafts were lost in group 2. Immature glomeruli were observed in three preimplantation biopsy samples. Graft survival was significantly longer in group 2 (hazard ratio, 0.5 [95% CI, 0.28–0.91]; p = 0.025). In a multivariate analysis, donor age (p = 0.01) and ischemia time (p = 0.02) were independent factors affecting graft survival. En bloc kidney transplantation from donors aged less than one year was associated with high early graft loss and poor long-term survival rates. Further investigations are needed to confirm the possible relationship to the histological glomerular maturity.