Poor Long-term Graft Function Research Articles

Arteriolar hyalinization at 0-hour biopsy predicts long-term graft function in deceased kidney transplantation.

Regarding the relationship between donor kidney quality and renal graft function after deceased kidney transplantation (KTx) following donation after cardiac death (DCD), the evaluation timing varies depending on the study. Evaluation of histology and changes in long-term renal graft function is limited. A retrospective single-center study included 71 recipients who underwent 0-hour biopsy for KTx from DCD. The recipients were divided into two groups to evaluate factors related to renal graft function (study1). The two groups were categorized as stable graft function and poor graft function with the change of estimated glomerular filtration rate (eGFR) after KTx. The recipients were then divided into four groups to assess whether the factors identified in study1 were related to the change in long-term renal graft function (study2). They were categorized as follows: Improved, Stable, Deteriorated, and Primary non-function with the change of eGFR after KTx. In study1, donor age ≥ 50 years (29.5% vs. 65.2%; p = 0.09), banff arteriolar hyalinosis (ah) score (0.66 ± 0.78 vs. 1.2 ± 1.0; p = 0.018), and presence of glomerulosclerosis (43.2% vs. 76.2%; p = 0.017) were significant risk factors for poor long-term graft function. When the recipients were divided into four groups, the severity of ah correlated well with changes in long-term renal function. We can predict the shift in long-term renal graft function after KTx from DCD according to the severity of ah by 0-hour biopsy.

Current unmet needs in renal transplantation: a review of challenges and therapeutics.

While has been considerable progress in the short-term outcomes following renal transplantation over the last several decades, minimal gains have been made with regards to long-term graft function and patient survival (1). The lack of long-term gains has been attributed to factors such as antibody mediated rejection (AMR), chronic allograft nephropathy (CAN), and toxicity to the allograft secondary to immunosuppression. Ischemia reperfusion injury (IRI) is also thought to contribute to poor long-term graft function, and its impact on patient and graft outcomes will likely expand with the increasing use of marginal kidneys secondary to organ shortages. While patient survival remains far below that of the general population, the causes of death have evolved in recent years with decreases in the rate of death from cardiovascular disease and infection, and increases secondary to malignancy (2), which are largely attributable to the potency of modern immunosuppression. As such, the development of novel therapies which can prevent delayed graft function (DGF), minimize AMR, while simultaneously reducing toxicity is vital to the improvement of long-term graft and patient outcomes.

Immunosuppressive drugs affect induction of IFNy+ Treg in vitro

BackgroundWe reported previously that patients with poor long-term graft function are able to form IFNy+ Treg in vitro pretransplant, but late posttransplant have more frequently undetectable or lower levels of IFNy+ Treg in the peripheral blood than patients with good long-term graft outcome. In the present study, we investigated the induction of IFNy+ and Tbet+ Treg subsets in the presence of immunosuppressants in vitro. MethodsPBL of 10 healthy individuals were stimulated with PMA/Ionomycin in the presence of different immunosuppressive drugs at 2 different concentrations that were chosen to approximately mirror the blood levels in renal transplant recipients. IFNy+, Tbet+, CD119+, and Helios+ CD4+CD25+CD127−Foxp3+ Treg subsets were analyzed using 8-color-fluorescence-flow-cytometry. ResultsCyclosporine (p<0.01) and 6α-methylprednisolone (p<0.05) at both concentrations as well as high doses of azathioprine (p<0.05) and mycophenolate mofetil (p<0.05) inhibited the induction of IFNy+ and Tbet+ Treg, whereas lower concentrations of azathioprine and mycophenolate mofetil tended to increase IFNy+, Tbet+ and CD119+ Treg (p⩽0.05). ConclusionsDrug-induced inhibition of Treg induction might result in low IFNy+ Treg levels with the consequence of T effector activation and impaired graft function. Further studies will show whether monitoring of IFNy+ Treg might help to prevent clinical complications provoked by an inappropriate immunosuppressive protocol.

Urine Liver-Type Fatty Acid-Binding Protein Predicts Graft Outcome up to 2 Years After Kidney Transplantation

BackgroundSeveral new biomarkers for the detection of early tubular injury have been investigated in kidney transplant recipients. We recently identified day 2 urinary neutrophil gelatinase-associated lipocalin (NGAL) as a predictor of slow graft function and adverse 1-year outcome. In the present study, we further investigated the value of urinary NGAL and liver-type fatty acid binding protein (L-FABP) for predicting long-term graft outcomes up to 2 years. MethodsThis study was a single-center, prospective observational study. Serial urinary NGAL and L-FABP levels at 0 hours, 2 days, and 6 days after kidney transplantation (KT) were measured, and the clinical data were assessed during the 2-year period after KT. ResultsDuring the 2-year follow-up period, 13 (18.8%), 5 (7.2%), and 4 (5.8%) patients were diagnosed with acute T-cell–mediated rejection, acute antibody-mediated rejection (AMR) and chronic AMR, respectively. In addition, 10 patients (14.3%) developed calcineurin inhibitor toxicity and 6 (8.7%) developed BK viremia. The mean estimated glomerular filtration rates (eGFR) at 1 and 2 years after KT were 65.1 ± 19.1 and 58.5 ± 22.6 mL/min/1.73 m2, respectively, When poor long-term graft function was defined as eGFR of less than 50 mL/min/1.73 m2 at 2 years, elderly donors, acute rejection, and high 0-hour urinary L-FABP levels were significant risk factors. Furthermore, in rejection-free patients, L-FABP was strongly associated with poor long-term graft function (P = .006). Multivariate logistic regression analysis showed that high 0-hour L-FABP (P = .015) and acute rejection (P = .006) were independent factors predicting poor long-term graft function. Receiver operating characteristic analysis showed that the area under the curve for urinary L-FABP was 0.692 (P = .036). ConclusionsOur results suggest that urinary L-FABP may be a useful predictor of adverse long-term outcomes in KT patients.

Aging aggravates long-term renal ischemia-reperfusion injury in a rat model

AimIschemia-reperfusion injury (IRI) has been considered as the major cause of acute kidney injury and can result in poor long-term graft function. Functional recovery after IRI is impaired in the elderly. In the present study, we aimed to compare kidney morphology, function, oxidative stress, inflammation, and development of renal fibrosis in young and aged rats after renal IRI. Materials and methodsRat models of warm renal IRI were established by clamping left pedicles for 45 min after right nephrectomy, then the clamp was removed, and kidneys were reperfused for up to 12 wk. Biochemical and histologic renal damage were assessed at 12 wk after reperfusion. The immunohistochemical staining of monocyte macrophage antigen-1 (ED-1) and transforming growth factor beta 1 (TGF-β1) and messenger RNA level of TGF-β1 in the kidney were analyzed. ResultsRenal IRI caused significant increases of malondialdehyde and 8-hydroxydeoxyguanosine levels and a decrease of superoxide dismutase activity in young and aged IRI rats; however, these changes were more obvious in the aged rats. IRI resulted in severe inflammation and tubulointerstitial fibrosis with decreased creatinine (Cr) clearance and increased histologic damage in aged rats compared with young rats. Moreover, we measured the ratio of Cr clearance between young and aged IRI rats. It demonstrated that aged IRI rats did have poor Cr clearance compared with the young IRI rats. ED-1 and TGF-β1 expression levels in the kidney were significantly higher in aged rats than in young rats after IRI. ConclusionAged rats are more susceptible to IRI-induced renal failure, which may associate with the increased oxidative stress, increased histologic damage, and increased inflammation and tubulointerstitial fibrosis. Targeting oxidative stress and inflammatory response should improve the kidney recovery after IRI.

Increased Frequency of Pretransplant MLC-Induced CD4+CD25+Foxp3+IFNg+ Treg Associated with Poor Long-Term Graft Outcome

Recently, a new subset of induced regulatory T-cells (iTreg) was detected. IFNg-producing CD3+CD4+CD25+Foxp3+ PBL were shown to have an immunoregulatory role in long-term renal transplant recipients. This iTreg subset is more frequently detectable in the blood of patients with good than in the blood of patients with impaired long-term kidney graft function. In-vitro, separated CD3+CD4+CD25+Foxp3+IFNg+ PBL from primary MLCs of healthy controls suppressed secondary MLCs antigen-unspecifically. In the present study we tried to find indications of antigen-specific MLC suppression mediated by separated CD4+CD25+IFNg+ PBL. PBL of a healthy control (HC1) were stimulated in 6-day-MLC with irradiated PBL of 2 HLA class-I/II incompatible healthy controls (HC2, HC3). CD4+CD25+IFNg+ PBL were separated from primary MLC and added to secondary 6-day-MLC. Secondary MLC HC1 versus HC2 showed 9.3% blasts, secondary MLC HC1 versus HC2 co-cultured with separated CD4+CD25+IFNg+ PBL from primary MLC HC1 versus HC3 exhibited 5.0% blasts, whereas secondary MLC HC1 versus HC2 cocultured with separated CD4+CD25+IFNg+ PBL from primary MLC HC1 versus HC2 exhibited only 1.7% blasts. Similar findings were observed for secondary MLC HC1 versus HC3 co-cultured with corresponding CD4+CD25+IFNg+ PBL from primary MLC: 7.0% blast formation in primary MLC, 2.1% blasts in third-party, and 2.0% blasts in autologous secondary MLC. These data suggest that primary MLC-derived CD4+CD25+IFNg+ PBL inhibit the allogeneic immune response in secondary MLC unspecifically. However, the strongest suppression was observed in antigen-specific MLC/iTreg combinations, suggesting antigen-specific suppression by a subset of separated CD4+CD25+IFNg+ PBL. Next, we studied whether patients with good long-term graft outcome (n=3; current serum creatinine 0.9-1.3 mg/dl) might show a higher frequency of iTreg in MLC than patients with intermediate (n=3, current serum creatinine 1.8-2.7 mg/dl) or poor long-term graft function (n=2, current serum creatinine 11 and 14 mg/dl). All patients were studied >15 years posttransplant (range: 18 - 29 years). Recipients shared a maximum of 3 HLA class I/II mismatches with the original graft donor. PBL obtained prior to transplantation and stored in liquid nitrogen were used. Recipient PBL were stimulated with either donor or pooled third-party PBL for 6 days. Then, CD4+CD25+ PBL co-expressing Foxp3+IFN-g+, GARP+Foxp3+, or GARP+IFNg+ were determined using four-color fluorescence flow-cytometry. Cell proliferation was measured using CFSE-staining of responder cells. Patients with impaired long-term graft outcome showed a stronger anti-donor response than patients with good long-term graft outcome. They exhibited stronger cell proliferation in recipient/donor MLC and increased iTreg induction in recipient/donor as well as recipient/third-party MLC. Thus, strong iTreg and blast induction in pretransplant MLCs with donor cells was associated with impaired long-term graft outcome. We conclude that CD4+CD25+Foxp3+IFNg+ PBL represent a heterogenous population containing iTreg that suppress allogeneic T-cell responses and may be involved in inhibition of the specific posttransplant alloresponse. As published, CD4+CD25+Foxp3+IFNg+ iTreg express IFNg receptors, are induced by IFNg and represent the first line of iTreg during an initiating immune response. Therefore, increased MLC responses are associated with increased induction of IFNg-sensitive CD4+CD25+Foxp3+IFNg+ iTreg in-vitro, thus explaining our finding that high pretransplant iTreg frequencies in-vitro are associated with poor long-term graft outcome.

Urinary NGAL, but not L-FABP, in Early Post-Transplant Period, Predicts Graft Outcome Up to 1 Year after Kidney Transplantation

Background: Several recent reports demonstrated the usefulness of new biomarkers in early post-transplant period for predicting delayed graft function (DGF) after kidney transplantation. However, the usefulness of these biomarkers in predicting long-term graft outcome has scarcely been assessed. Methods: This was a prospective observational study, and only recipients without evidence of DGF, a well-known risk factor for poor long-term outcome, were included for the analysis (n=62). Urine samples at 0 hr, day 2 and 6 were obtained. Results: Urinary neutrophil gelatinase-associated lipocalin (u-NGAL) level on day 2, but not liver type fatty acid binding protein (L-FABP) or serum creatinine, was significantly higher in slow graft function (SGF) compared to immediate graft function (IGF) group. Higher day 2 u-NGAL level was associated with more frequent development of SGF and in addition, it was also associated with significantly lower 1yr estimated glomerular filtratrion rate (eGFR). In multivariate logistic regression analysis, day 2 u-NGAL was a significant, independent factor for predicting poor long-term graft function (1yr eGFR< 60ml/min/1.73m2). Conclusions: This study first demonstrated the possibility that u-NGAL might also be useful in predicting long-term graft outcome as well as short-term function even in patients who showed favorable early clinical course with early graft function (EGF).

Urine Neutrophil Gelatinase-Associated Lipocalin Predicts Graft Outcome up to 1 Year After Kidney Transplantation

BackgroundSeveral recent reports demonstrated the usefulness of new biomarkers in early prediction of delayed graft function (DGF) and graft recovery after kidney transplantation (KT). It is unknown, however, whether these biomarkers would predict long-term graft outcome. In this study, we examined whether the biomarkers including neutrophil gelatinase-associated lipocalin (NGAL) and liver-type fatty acid-binding protein (L-FABP) can predict 1-year graft outcome as well as short-term graft function especially in patients with early graft function (EGF). MethodsThis was a single-center, prospective observational study. Urine samples at 0 hours and 2 and 6 days were obtained and the level of NGAL and L-FABP were measured. ResultsOf the 69 KT recipients enrolled, seven developed DGF, and the remaining 62 patients were finally enrolled as EGF recipients. EGF recipients were additionally divided into immediate graft function (IGF, n = 48) and slow graft function (SGF, n = 14) groups. Urinary NGAL (u-NGAL) level on day 2, but not L-FABP nor serum creatinine, was significantly higher in SGF compared to IGF group. Higher day 2 u-NGAL level was associated with more frequent development of SGF and, in addition, with significantly lower 1-year estimated glomerular filtration rate (eGFR). In multivariate logistic regression analysis, day 2 u-NGAL was a significant, independent factor for predicting poor long-term graft function (1-year eGFR < 60 mL/min/1.73 m2). ConclusionsThis study demonstrates the possibility that u-NGAL might be useful in predicting adverse 1-year outcome as well as short-term graft function even in EGF patients.

Impact of Human Leukocyte Antigen-DR Mismatch Status on Kidney Graft Survival in a Predominantly African-American Population Under the Newer Immunosuppressive Era

Background Human leukocyte antigen (HLA)-DR has been shown to be immunogenic and associated with poor long-term graft function. However, under potent induction immunosuppression with antithymocyte globulin, the impact of the HLA-DR remains unclear. Method We reviewed 672 renal transplant recipients who received their transplants between 1998 and 2007. All patients received antithymocyte globulin as induction therapy followed by tacrolimus + prednisone + mycophenolate mofetil for maintenance immunosuppression. We divided the patients into three groups according to HLA-DR mismatch status (zero, one, or two mismatches). Results The three groups were different in total number of mismatches, deceased donor transplant, and delayed graft function, respectively. By Kaplan-Meier survival analysis, actuarial graft survival was significantly lower in the HLA-DR two mismatches group (72%) compared to HLA-DR zero mismatches group (78.5%) or HLA-DR one mismatch group (78.5%; P = .05, by log-rank test). Using Cox regression analysis, the risk of graft failure with two HLA-DR mismatches as compared with zero HLA-DR mismatches was 1.6 (95% confidence interval = 1.0–2.44, P = .049). When adjusted for age, wait time, race, type of transplant, retransplant status, T-cell flow crossmatch, delayed graft function, acute rejection, HLA-A and HLA-B, the effect of HLA-DR on survival was not significant ( P = .55). Conclusion The independent effect of HLA-DR mismatches on adverse graft survival is diminished under potent antibody induction and maintenance immunosuppression in our predominantly African-American population.

Extensive human cytomegalovirus (HCMV) genomic DNA in the renal tubular epithelium early after renal transplantation: Relationship with HCMV DNAemia and long‐term graft function

Human cytomegalovirus (HCMV) infection is associated with a series of direct and indirect effects following renal transplantation. However, the presence of HCMV in the kidney and its relationship with acute rejection and long-term graft function remain to be fully elucidated. Sixty-two biopsies derived from 30 renal transplant recipients with signs of clinical rejection were analyzed for HCMV using a sensitive in situ DNA hybridization method. Biopsies were also subjected to staining with anti-C4d antibodies and an anti-caspase 3 antibody to detect humoral rejection and apoptosis, respectively. In 21 patients, serial serum creatinine levels over 5 years of follow-up were analyzed. HCMV DNA was detected in biopsies from 21/30 (70%) of the patients and 32/62 (52%) of the individual biopsies. HCMV DNA was detected early after transplant and was localized to renal tubule epithelial cells but not associated with apoptosis. HCMV DNAemia developed within 2 weeks of detecting HCMV DNA in the biopsy in 53% of patients. Ninety percent of patients experiencing HCMV disease had HCMV DNA in their biopsy. HCMV DNA was equally distributed between patients with or without histological evidence of acute rejection and was detected more frequently in patients with peritubular C4d deposits. Creatinine levels at 12 months post-transplant were significantly higher in patients with HCMV DNA and remained elevated over the 5 years of follow-up. HCMV DNA is frequently detected in renal tubular epithelial cells early after renal transplantation, precedes DNAemia and is associated with poor long-term graft function.

Prognostic Value of Absent End-Diastolic Flow Within the First Week Following Renal Transplantation

Background Doppler sonogram of the graft is used as a routine assessment in renal transplantation. When the resistance index (RI) equals 1, absent end-diastolic flow (AEDF) is observed; the prognostic value of AEDF is presently unknown. Patients and Methods Between 1988 and 1996, 342 patients received a first cadaveric kidney transplant in our ward. AEDF was observed in 30 patients who were compared with 60 controls who showed an RI < 0.75 within the first 7 days after transplantation. They were matched for year of transplantation (±1 year); recipient age (±2 years); recipient sex; and HLA antibodies (3 classes: 0%, 1–75%, >75%). The follow-up was 4 years. Results AEDF was observed at day 1 in 64%, at day 3 in 96%, and at day 7 in 28%. Recipient age, donor age, recipient sex, cold and warm ischemia durations, HLA A, B, and DR mismatches, and cytomegalovirus (CMV) status were not different between the 2 groups. Immediate graft function and 3- to 24-month creatinine levels were better in the control than the AEDF group. However, there was no difference in serum creatinine at 3 and 4 years or in patient and graft survivals during follow-up. Conclusions AEDF observed within the first week following transplantation is associated with impaired renal functional recovery. However, whether AEDF is a prognostic marker of poor long-term graft function or survival remains to be proven.

Macrophages contribute to the development of renal fibrosis following ischaemia/reperfusion-induced acute kidney injury

Ischaemia/reperfusion is a major cause of acute kidney injury and can result in poor long-term graft function. Although most of the patients with acute kidney injury recover their renal function, significant portion of patients suffer from progressive deterioration of renal function. A persistent inflammatory response might be associated with long-term changes following acute ischaemia/reperfusion. Macrophages are known to infiltrate into tubulointersitium in animal models of chronic kidney disease. However, the role of macrophages in long-term changes after ischaemia/reperfusion remains unknown. We aimed to investigate the role of macrophages on the development of tubulointerstitial fibrosis and functional impairment following acute ischaemia/reperfusion injury by depleting macrophages with liposome clodronate. Male Sprague-Dawley rats underwent right nephrectomy and clamping of left renal vascular pedicle or sham operation. Liposome clodronate or phosphate buffered saline was administered for 8 weeks. Biochemical and histological renal damage and gene expression of various cytokines were assessed at 4 and 8 weeks after ischaemia/reperfusion. Ischaemic/reperfusion injury resulted in persistent inflammation and tubulointerstital fibrosis with decreased creatinine clearance and increased urinary albumin excretion at 4 and 8 weeks. Macrophage depletion attenuated those changes. This beneficial effect was accompanied with a decrease in gene expression of inflammatory and profibrotic cytokines. These results suggest that macrophages play an important role in mediating persistent inflammation and fibrosis after ischaemia/reperfusion leading to a development of chronic kidney disease. Strategies targeting macrophage infiltration or activation can be useful in the prevention of development of chronic kidney disease following ischaemic injury.

Early post-transplant urinary IP-10 expression after kidney transplantation is predictive of short- and long-term graft function

The early identification of renal transplant recipients at enhanced risk of developing acute and subclinical rejection would allow individualized adjustment of immunosuppression before functional graft injury occurs and would exclude these patients from drug-weaning studies. Protein and reverse transcriptase-polymerase chain reaction-based analyses of candidate markers in urine open the opportunity to closely monitor kidney-transplanted patients non-invasively. The chemokine interferon-inducible protein 10 (IP-10; CXCL10) might be an interesting candidate to uncover ongoing immune processes within the graft. Urine samples from kidney-transplanted recipients were retrospectively analyzed for IP-10 mRNA and protein expression. IP-10 levels were correlated with the incidence of acute rejection episodes proven by histology and long-term graft function assessed by the glomerular filtration rate 6 months post transplantation. IP-10 expression in urine identified patients with ongoing acute rejection episodes several days before a biopsy was indicated by rising serum creatinine levels. Most importantly, elevated levels of urinary IP-10 protein within the first four postoperative weeks were predictive of graft function at 6 months even in the absence of acute rejection. These data reveal a correlation between elevated IP-10 expression in urine at early time points post-transplantation and intragraft immune activation that leads to acute rejection and compromised long-term graft function.

Re: the association of viral infection and chronic allograft nephropathy with graft dysfunction after renal transplantation

Background. The long-term effect of viral infections on graft dysfunction and rejection after renal transplantation is uncertain. Methods. A cohort of 37 renal transplant recipients was followed prospectively for 3 years. Creatinine clearance rate at 6 months and 3 years and chronic allograft nephropathy were correlated with the detection of cytomegalovirus (CMV), human herpesvirus 6 and human herpesvirus 7 and BK virus DNA, CMV disease, and acute rejection. Results. CMV disease was significantly associated with poor graft function at 6 months, whereas chronic allograft nephropathy was associated with graft dysfunction at 3 years. Both CMV disease and detection of human herpesvirus 6 DNA were associated with chronic allograft nephropathy. Conclusions. CMV disease was a significant cause of early graft dysfunction, whereas the presence of chronic allograft nephropathy was the main determinant of poor long-term graft function. The role of viral infections in chronic allograft nephropathy deserves further investigation.