Delayed Allograft Function Research Articles

Inhibition of TLR2 promotes graft function in a murine model of renal transplant ischemia‐reperfusion injury

Toll-like receptors (TLRs) are important molecules involved in the activation of innate and subsequent development of adaptive immunity. TLRs are ligated by exogenous ligands from pathogens and by endogenous ligands released in inflammatory diseases. Activation of TLR leads to activation of NF-κB and release of proinflammatory cytokines, such as IL-6 and TNF-α. TLRs play an important role in the pathogenesis of renal diseases. Increased expression of TLRs have been associated with ischemic kidney damage, acute kidney injury, end-stage renal failure, acute renal transplant rejection, and delayed allograft function. OPN301 is a mouse anti-human TLR2 antibody that cross-reacts with mouse TLR2. We show that inhibition of TLR2 promotes graft function in an isograft model of renal transplantation. Recipient mice were treated intravenously with OPN301 before reperfusion of the transplanted kidney that had been subjected to 30 min of cold ischemia. After 5 d, the residual native kidney was removed, and renal transplant function was assessed 24 h later by measurement of blood urea nitrogen. Renal function in both saline- and isotype-treated mice was similar, with significant improvement in OPN301-treated mice (isotype-treated vs. OPN301-treated: 33.9±3.2 vs. 19.8±1.9 μM; P<0.01). The histopathological appearance corresponded with renal functional results. In OPN301-treated recipients, renal structure was well preserved, whereas in the saline-treated group, tubular injury was severe, with marked tubular thinning, epithelial shedding, cast formation and necrosis. Inhibition of TLR2 also leads to a decrease in C3d deposition, although it is unclear whether this is due directly to TLR2 inhibition or a decrease in renal inflammation. This study shows that inhibition of TLR2 with a therapeutic agent (OPN301) provides significant protection from ischemia/reperfusion injury in a model of kidney transplantation.

Successful transplantation of a donor kidney with diffuse proliferative lupus nephritis and crescents--a case report

Pre-existing diffuse proliferative glomerulonephritis (DPGN) in a potential deceased kidney donor has been considered a contraindication for transplantation. We report a case of a patient who underwent a successful deceased donor renal transplantation from a donor with history of systemic lupus erythematosus (SLE) whose baseline biopsy revealed DPGN. Although the histology was relatively benign in the procurement kidney biopsy done by frozen section, the final light microscopy available after transplantation showed diffuse proliferative lupus nephritis, WHO class IV, with 44% crescents. The post-transplant course was complicated by delayed allograft function requiring haemodialysis for the first week. A repeat biopsy performed after 4 months of transplant showed resolution of the proliferative lesions in the glomeruli with disappearance of the crescents. At 5.5 years of follow-up, the patient's creatinine has been stable at 2.0 mg/dL (176.8 μmol/L), but he has persistent proteinuria.

The role of Toll-like receptors in renal diseases

Toll-like receptors (TLRs) have a key role in innate immunity. These receptors recognize both pathogen-associated molecular patterns and molecules that are released from damaged tissue. TLRs mediate signal transduction pathways through the activation of transcription factors that regulate the expression of proinflammatory cytokines and chemokines and are required for the development of adaptive immune responses. TLRs might have an important role in the pathogenesis of renal diseases: their exaggerated activation is associated with ischemic kidney damage, acute kidney injury, end-stage renal failure, acute tubulointerstitial nephritis, acute renal transplant rejection and delayed allograft function. As the results of previous studies concerning the role of TLRs in renal diseases are conflicting, further work is needed to determine the exact role of these receptors and to evaluate strategies to prevent TLR-mediated local inflammation. This Review discusses the evidence supporting a role for TLRs in contrasting bacterial infections and in causing or aggravating renal conditions when TLR activation leads to a harmful inflammatory response.

Maximizing the donor pool: use of right kidneys and kidneys with multiple arteries for live donor transplantation

Studies have shown donor and recipient outcomes to be equivalent for laparoscopic donor nephrectomy (LDN) and open donor nephrectomy. In the past, LDN has been avoided in the procurement of the right kidney or organs with multiple arteries. This study compares procurement of right and left kidneys as well as procurement of single- and multiple artery organs. A review of all LDNs at a single institution between August 2000 and December 2007 was performed. The data included estimated blood loss (EBL), need for transfusion, operative time, warm ischemia time, length of hospital stay (LOS), and delayed graft function. Arterial supply was assessed using renal arteriogram or computed tomographic (CT) angiography. Outcomes for multiple versus single artery and left versus right LDN were compared. Student's t-test and chi-square test were used for statistical comparison. A total of 230 LDNs were performed. Multiple arteries were present in 37 donors. The right kidney was procured from 36 donors. No significant difference in EBL, transfusions, operative time, or LOS was noted between multiple and single or right and left LDNs. Warm ischemia time was significantly longer for multiple arteries (mean, 83 s) than for single arteries (mean, 63 s; p = 0.007), and for right kidneys (mean, 86 s) than for left kidneys (mean, 62 s; p = 0.001). No significant difference in delayed graft function was seen in the comparison of multiple (21.6%) and single (11.4%) artery organs (p = 0.11) or of right (13.9%) and left (12.9%) kidneys (p = 0.79). The presence of multiple arteries or the need to procure the right kidney does not affect the operative outcome of laparoscopic donor nephrectomy. Warm ischemia time may be greater for these groups, but this does not result in delayed allograft function. The laparoscopic approach should be the standard of care even when expansion of the donor pool includes organs with multiple arteries and procurement of the right kidney.

HLA-A amino acid polymorphism and delayed kidney allograft function

Delayed allograft function (DGF) is a common adverse event in postrenal transplantation. The etiology of DGF is thought to include both nonimmunologic (donor age, cold ischemia time, and recipient race) and immunologic factors. We examined the association of DGF with amino acid mismatches at 66 variable sites of the HLA-A molecule in a prospective cohort study of 697 renal transplant recipients of deceased donors. Using a multivariate logistic regression model adjusted for nonimmunologic risk factors, we show that combinations of a few amino acid mismatches at crucial sites of HLA-A molecules were associated with DGF. In Caucasian recipients, a mismatch at position 62, 95, or 163, all known to be functionally important within the antigen recognition site, was associated with an increased risk for DGF. Furthermore, a decreased risk for DGF was associated with a mismatch at HLA-A family-specific sites (149, 184, 193, or 246), indicating that evolutionary features of HLA-A polymorphism separating HLA-A families and lineages among donor-recipient pairs may correlate with the magnitude of alloreactivity influencing the development of DGF. These findings suggest that amino acid polymorphisms at functionally important positions at the antigen recognition site of the HLA-A molecule have a significant influence on DGF.

Association of Donor Inflammation- and Apoptosis-Related Genotypes and Delayed Allograft Function After Kidney Transplantation

Delayed renal allograft survival (delayed graft function [DGF]) after deceased donor kidney transplantation is associated with an increased risk of allograft loss. Inflammatory response and apoptosis are associated with increased risk of DGF. Cross-sectional study. We first recruited 616 recipients of kidneys from 512 deceased kidney donors, and donor DNA was genotyped. These recipients, who were included in a prospective cohort study of 9 transplant centers in the Delaware Valley region, had their DGF outcome obtained through medical record abstraction. We then identified the recipient (n = 349) of the contralateral deceased kidney donor, if not part of the cohort, through the US Renal Data System registry. The final cohort consisted of 965 recipients of deceased donor kidneys from 512 donors. Donor single-nucleotide polymorphisms in genes for tumor necrosis factor alpha (TNF), transforming growth factor beta1 (TGFB1), interleukin 10 (IL10), p53 (TP53), and heme oxygenase 1 (HMOX1). DGF, defined as the need for dialysis therapy in the first week posttransplantation. Secondary outcomes included acute rejection and estimated glomerular filtration rate. Information for DGF, acute rejection, and estimated glomerular filtration rate for recipients in the Delaware Valley Cohort was obtained through medical record abstraction. For other recipients, information for DGF was obtained from United Network for Organ Sharing forms and Centers for Medicare & Medicaid Services claims in the US Renal Data System registry. No association was detected between the TGFB1, IL10, TP53, and HMOX1 genes and DGF. The G allele of the TNF polymorphism rs3093662 was associated with DGF in an adjusted analysis (odds ratio, 1.85 compared with A allele; 95% confidence interval, 1.16 to 2.96; P = 0.01). However, this association did not achieve statistical significance after adjusting for multiple comparisons. Inadequate sample size for infrequent genotypes and multiple comparisons. Because of the low frequency of donor single-nucleotide polymorphisms of interest, a larger sample size and replication are necessary to confirm these findings on the association of donor genotypes with DGF.

The Association Between Angiotensin Converting Enzyme Inhibitor or Angiotensin Receptor Blocker Use During Postischemic Acute Transplant Failure and Renal Allograft Survival

Postischemic acute renal transplant failure occurs in approximately one fourth of all dead donor transplantations. Uncertainty exists regarding the putative association between the use of angiotensin converting enzyme inhibitors (ACEIs) or angiotensin II AT1 receptor blockers (ARBs) and kidney transplant graft survival in patients with delayed allograft function. We conducted an open cohort study of all 436 patients who experienced an acute renal transplant failure out of all 2,031 subjects who received their first kidney transplant at the Medical University of Vienna between 1990 and 2003. Actual and functional graft survival was compared between users and nonusers of ACEI/ARB using exposure propensity score models and time-dependent Cox regression models. Ten-year actual graft survival averaged 44% in the ACEI/ARB group, but only 32% in patients without ACEI/ARB (P=0.002). The hazard ratio of actual graft failure was 0.58 (95% confidence interval: 0.35-0.80, P=0.002) for ACEI/ARB users compared with nonconsumers. Seventy-one percent of subjects with ACEI/ARB had a functional graft at 10 years versus 64% of ACEI/ARB nonusers (P=0.027). The hazard ratio of functional graft loss was 0.48 (95% confidence interval: 0.24-0.91, P=0.025). Use of ACEI/ARB in patients experiencing delayed allograft function was associated with longer actual and functional transplant survival.

Duffy antigen receptor and genetic susceptibility of African Americans to acute rejection and delayed function

The unique distribution of the alleles for the Duffy antigen receptor complex (DARC) that binds to chemokines may be associated with the rates of acute rejection and delayed allograft function (DGF) among African Americans. A prospective, multicenter cohort study enrolled 222 African American recipients of cadaveric renal allografts from eight adult transplant centers. Subjects were typed by allele-specific polymerase chain reaction (ASPCR) for the polymorphism at position 535 that determines the level of transcription. Associations of DARC genotypes were examined in Cox hazards models with episodes of acute rejection and in logistic regression models with the development of DGF. FyB Null homozygosity was observed among 67% of the recipients. Fifteen percent of the study cohort experienced at least one episode of acute rejection, and the incidence of DGF was 42.5%. The number of FyB Null alleles and FyB Null homozygosity had no detectable association with the rate of acute rejection (P > 0.50) or with the development of DGF (P > 0.50). The susceptibility of African American recipients to acute rejection and to DGF was not confirmed to be associated with DARC alleles or genotype. Future studies should exclude a potential role of donor-related DARC in transplant outcomes.

Impaired tubulointerstitial expression of endothelin-1 and nitric oxide isoforms in donor kidney biopsies with postischemic acute renal failure.

About 30% of cadaveric renal allografts, but almost never living-donor kidneys, develop postischemic acute renal-transplant failure (ARF). We therefore quantified the expression of essential reperfusion regulators in different compartments of cadaveric and living-donor kidney biopsies. Specimens were obtained from donor kidneys at the end of the cold ischemia time before implantation and categorized into three groups according to donor source and early posttransplant function. Ten living-donor biopsies (LIV) were compared with nine cadaveric kidney biopsies (CAD) with primary posttransplant function (CAD-PF) and to nine with ARF (CAD-ARF). Laser capture microdissection was used to isolate glomeruli from tubulointerstitium. The gene expression of intercellular adhesion molecule (ICAM)-1, interleukin (IL)-1beta, endothelin (ET)-1, inducible nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS) was quantified in glomeruli and tubulointerstitium by real-time polymerase chain reaction (TaqMan). Tubulointerstitial areas of all CAD kidneys revealed significantly lower mRNA levels of all investigated genes compared with LIV. Tubulointerstitial ET-1, iNOS, and eNOS in CAD-ARF averaged only half of the expression in CAD-PF kidneys. ICAM-1 and IL-1beta mRNA concentrations were equal in CAD-PF and CAD-ARF. Glomerular expression of the investigated genes was equal in CAD and LIV kidneys with the exception of ICAM-1 and ET-1, which were two times higher in CAD-PF compared with LIV and CAD-ARF. These data suggest that CAD compared with LIV kidneys have an impaired expression of immune and vasoregulatory genes in the tubulointerstitium, which may represent reduced cellular vitality and capacity to adaptation. The observed further reduction of ET-1, iNOS, and eNOS expression in CAD-ARF might contribute to reperfusion injury and delayed allograft function.

Drug-induced acute interstitial nephritis in renal allografts: histopathologic features and clinical course in six patients.

Drug-induced acute interstitial nephritis is a common cause of dysfunction in native kidneys, but is rarely reported in renal allografts. This report describes six renal transplant recipients with acute renal allograft dysfunction or delayed allograft function in whom a renal transplant biopsy showed histopathologic features of drug-induced interstitial nephritis with no diagnostic evidence of acute rejection, cyclosporine or tacrolimus nephrotoxicity, or other lesion that could account for the graft dysfunction. In five of the six patients, interstitial nephritis occurred within 4 weeks of transplantation. All the patients were receiving trimethaprim-sulfamethoxazole and/or other drugs associated with interstitial nephritis. After discontinuation of these drugs and short-term corticosteroid treatment, all patients showed improvement in renal function, although the time course of this improvement varied considerably, with three patients showing a return to baseline serum creatinine level within 2 weeks and two patients showing a gradual improvement over 8 weeks. Four of the five patients followed up for more than 1 year (range, 14 to 33 months) after the episode of interstitial nephritis had good allograft function (serum creatinine level </= 1.6 mg/dL) at most recent follow-up, with one patient who had graft loss because of severe rejection 7.5 months after the development of interstitial nephritis. These findings suggest drug-induced interstitial nephritis may be an infrequent cause of graft dysfunction in kidney transplant recipients. Drug-induced interstitial nephritis is a reversible lesion that should be considered in the differential diagnosis of acute renal allograft dysfunction.

Centralization of histocompatibility laboratories: impact on organ allocation efficiency and outcomes of cadaveric renal transplantation.

This project was undertaken to determine whether centralization of histocompatibility laboratory services for renal transplants performed within eastern Pennsylvania could improve the efficiency of allograft allocation and short-term allograft function. A nonconcurrent cohort study was performed comparing renal allografts transplanted between September 15, 1993, and September 14, 1994, to those transplanted between September 15, 1994, and September 14, 1995. All allografts were procured and allocated by the Delaware Valley Transplant Program, the organ procurement agency in eastern Pennsylvania. Cold preservation time and delayed allograft function were used to measure efficiency of allograft allocation and short term allograft function, respectively. The mean cold preservation time was reduced from 25.08 hours to 20.68 hours (P < 0.001). The percentage of delayed allograft function was 19.9 and 17.4 for the pre- and postcentralization groups, respectively (P = 0.5). Therefore, centralization of histocompatibility tissue typing was a regionally effective process intervention for reducing cold preservation time without adversely impacting short-term graft function. The magnitude of this reduction varied between individual centers. Further investigation is required to determine the effect on long-term allograft function and system wide costs.

The effect of antilymphocyte induction therapy on renal allograft survival. A meta-analysis of individual patient-level data. Anti-Lymphocyte Antibody Induction Therapy Study Group.

Randomized, controlled trials have not shown that the perioperative use of antilymphocyte antibodies (induction therapy) improves survival of cadaveric kidney allografts. This study combined individual patient-level data from published trials to examine the effect of induction therapy on allograft survival. Randomized, controlled trials identified from MEDLINE. Published trials that compared adult recipients of cadaveric renal allografts who did and did not receive antilymphocyte antibodies in the perioperative period were selected if individual patient-level data were available. Individual patient-level data were collected for each of 628 study patients. Multivariable Cox proportional hazards regression was used to estimate the effect of induction therapy on allograft survival. The adjusted rate ratio for allograft failure with induction therapy compared with conventional therapy was 0.62 (95% CI, 0.43 to 0.90) (P = 0.012) over 2 years and 0.82 (CI, 0.62 to 1.09) (P = 0.17) over 5 years. The effect of induction therapy on allograft survival diminished over time; no benefit overall was seen after 2 years after transplantation (rate ratio, 1.13 [CI, 0.72 to 1.78]) (P > 0.2). Greater HLA-DR mismatch, delayed allograft function, diabetes mellitus in the recipient, African-American ethnicity of the recipient, and presensitization (panel-reactive antibody levels > or = 20%) were significantly associated with allograft failure at 5 years. Among high-risk patients, only those who were presensitized benefited from induction therapy at 2 years (rate ratio, 0.12 [CI, 0.03 to 0.44]) (P = 0.001). Results were similar at 5 years. Using individual-level data, this study showed a benefit of induction therapy at 2 years, particularly among presensitized patients. Although the benefit of this therapy subsequently waned, presensitized patients continued to have benefit at 5 years.

Race and delayed kidney allograft function.

Allograft survival among black recipients is poorer than among whites. Delayed allograft function is associated with a significant reduction in renal allograft survival. The relationship between delayed allograft function and black race is incompletely specified and was the focus of this investigation. A non-concurrent study of 325 recipients of cadaveric allografts followed for the occurrence of delayed allograft function defined as dialysis during the first week following transplantation for the principal analysis. A secondary definition of delayed allograft function was formulated based on the serum creatinine 2 weeks after transplantation. Unadjusted and adjusted logistic regression analysis were used to examine the unconfounded relationship between race and delayed allograft function. Fifty-seven of 91 (62.6%) black recipients experienced delayed allograft function compared to 113 of 234 (48.3%) whites. The odds ratio for black race as a predictor of delayed allograft function was 1.80, P=0.02, (95% CI, 1.09, 2.95). This finding was stable despite adjustment for other predictors of delayed allograft function in a multivariate model, but the precision of this estimate was less (P=0.10) because of missing data. Additionally, adjusted models with imputed values for missing covariates, models using a secondary definition of delayed allograft function, and models excluding patients whose cyclosporin therapy was delayed, all consistently demonstrated a similar association between black race and delayed allograft function. This study demonstrated an increased risk of delayed allograft function among black recipients. This relationship may play a role in the poorer allograft outcomes experienced by black recipients. Given the negative effect of delayed allograft function on allograft survival, efforts to identify its modifiable risk factors should be a high priority.

Delayed function reduces renal allograft survival independent of acute rejection

Mechanisms by which delayed allograft function reduces renal allograft survival are poorly understood. This study evaluated the relationship of delayed allograft function to acute rejection and long-term survival of cadaveric allografts. 338 recipients of cadaveric allografts were followed until death, resumption of dialysis, retransplantation, loss to follow-up, or the study's end, which ever came first. Delayed allograft function was defined by dialysis during the first week following transplantation. Multivariate Cox proportional hazards survival analysis was used to assess the relationship of delayed allograft function to rejection and allograft survival. Delayed allograft function, recipient age, preformed reactive antibody levels, prior kidney transplantation, recipient race, rejection during the first 30 days and rejection subsequent to 30 days following transplantation were predictive of allograft survival in multivariate survival models. Delayed allograft function was associated with shorter allograft survival after adjustment for acute rejection and other covariates (relative rate of failure [RR]+1.72 [95% CI, 1.07, 2.76]). The adjusted RR of allograft failure associated with any rejection during the first 30 days was 1.99 (1.23, 3.21), and for rejection subsequent to the first 30 days was 3.53 (2.9 08, 6.00). The impact of delayed allograft function did not change substantially (RR=1.84 [1.15, 2.95]) in models not controlling for acute rejection. These results were stable among several subgroups of patients and using alternative definitions of allograft survival and delayed allograft function. This study demonstrates that delayed allograft function and acute allograft rejection have important independent and deleterious effects on cadaveric allograft survival. These results suggest that the effect of delayed allograft function is mediated, in part, through mechanisms not involving acute clinical rejection.

Recipient body size and cadaveric renal allograft survival.

Transplantation of renal allografts inadequate to meet recipient metabolic demands has been hypothesized to be one cause of chronic allograft failure. This cohort study examined the relationship of each of three measures of recipient body size and one measure of recipient metabolic rate to the rate of allograft failure among 239 recipients of cadaveric renal allografts between 1985 and 1990. All subjects were followed until allograft failure, death, or December 31, 1992, whichever occurred first. Using multivariate Cox proportional hazards analysis, all measures of recipient size and metabolic rate were found to be strong and statistically significant predictors of allograft survival adjusted for other predictors of allograft survival including allograft rejection, delayed allograft function, recipient race, prior renal transplantation, and donor age. The adjusted relative risk (RR) of allograft failure for a 15-kg increase in recipient body weight was 1.47, P < 0.0001 (95% confidence interval (CI), 1.21-1.78); adjusted RR for a 10-U increase in recipient body mass index was 2.34, P < 0.0001 (95% CI, 1.53-3.58); adjusted RR for a 0.5 m2 increase in recipient body surface area was 2.34, P < 0.001 (95% CI, 1.40-3.91); and adjusted RR for a 250 Kcal increase in metabolic rate was 1.49, P < 0.01 (95% CI, 1.17-1.89). These results are consistent with prior research indicating that a renal tissue supply-demand mismatch may accelerate failure of renal allografts. Alternative explanations of this relationship between recipient body size and allograft survival include inadequate immunosuppressive medication administration among recipients with a larger body size. Additional research is warranted to examine more fully the relationship between recipient body size and allograft survival.

Endogenous ANP in postischemic acute renal allograft failure.

Circulating atrial natriuretic peptide (ANP) levels and glomerular binding sites for ANP were examined in 23 subjects undergoing renal transplantation. Subjects were divided into two groups, group 1 (n = 12) with prompt and group 2 (n = 11) with delayed allograft function. Sixty to 180 min after graft reperfusion, renovascular resistance was threefold higher and glomerular filtration rate (GFR) depressed by 79% in group 2 vs. group 1. Corresponding median plasma ANP (114 vs. 140 pg/ml) and guanosine 3',5'-cyclic monophosphate (cGMP) levels (22 vs. 28 pmol/ml) were similarly elevated in the two groups [P = not significant (NS)]. Autoradiographic analysis of glomeruli in an allograft biopsy revealed the median density of total receptors (24 vs. 28 fmol/mm3), A receptors (15 vs. 19 fmol/mm3), and C receptors (6 vs. 9 fmol/mm3) for ANP to also be similar in group 2 vs. group 1, respectively (P = NS). By postoperative day 3, allograft GFR averaged only 6 +/- 2 in group 2 vs. 59 +/- 4 ml/min in group 1. Median plasma ANP levels doubled in each group to 262 and 251 pg/ml, respectively (P = NS). However, median values for plasma levels (38 vs. 17 pmol/ml) and the fractional clearance of cGMP (1.9 vs. 1.2) were significantly higher in group 2 than group 1. We conclude that, despite an adequate density of glomerular ANP receptors and enhanced cGMP generation, neither renal vasoconstriction nor hypofiltration is alleviated by a progressive elevation of plasma ANP levels in renal transplant recipients with sustained postischemic injury. We infer that constricted afferent arterioles are unresponsive to the vasorelaxant action of endogenous ANP in this form of postischemic, acute renal failure.