Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

New-Onset Anemia and Associated Risk of ESKD and Death in Non-Dialysis CKD Patients: A Multi-Cohort Observational Study

Background

Anemia is a common complication of chronic kidney disease (CKD), but its incidence in nephrology settings is poorly investigated. Similarly, the risks of adverse outcomes associated with new-onset anemia are not known.

Methods

We performed a pooled analysis of three observational cohort studies including 1031 non-anemic CKD patients with eGFR <60 mL/min/1.73 m² regularly followed in renal clinics. We estimated the incidence of mild anemia (hemoglobin 11–12 g/dL in women and 11–13 g/dL in men) and severe anemia (hemoglobin <11 g/dL or use of erythropoiesis-stimulating agents) during a 3-year follow-up period. Thereafter we estimated the risk of end-stage kidney disease (ESKD) and all-cause death associated with new-onset mild and severe anemia.

Results

The mean age was 63 ± 14 years, 60% were men and 20% had diabetes. The mean estimated glomerular filtration rate (eGFR) was 37 ± 13 mL/min/1.73 m² and the median proteinuria was 0.4 g/day [interquartile range (IQR) 0.1–1.1]. The incidence of mild and severe anemia was 13.7/100 patients-year and 6.2/100 patients-year, respectively. Basal predictors of either mild or severe anemia were diabetes, lower hemoglobin, higher serum phosphate, eGFR <30 mL/min/1.73 m² and proteinuria >0.50 g/day. Male sex, moderate CKD (eGFR 30–44 mL/min/1.73 m²) and moderate proteinuria (0.15–0.50 g/day) predicted only mild anemia. The incidence of anemia increased progressively with CKD stages (from 8.77 to 76.59/100 patients-year) and the proteinuria category (from 13.99 to 25.02/100 patients-year). During a median follow-up of 3.1 years, 232 patients reached ESKD and 135 died. Compared with non-anemic patients, mild anemia was associated with a higher adjusted risk of ESKD {hazard ratio [HR] 1.42 [95% confidence interval (CI) 1.02–1.98]} and all-cause death [HR 1.55 (95% CI 1.04–2.32)]. Severe anemia was associated with an even higher risk of ESKD [HR 1.73 (95% CI 1.20–2.51)] and death [HR 1.83 (95% CI 1.05–3.19)].

Conclusions

New-onset anemia is frequent, particularly in patients with more severe renal damage and in those with diabetes mellitus. The occurrence of anemia, even of a mild degree, is associated with mortality risk and faster progression towards ESKD.

AB1234 MICRO-RNA 155 AND MIR-34A: POSSIBLE BIOMARKERS OF INFLAMMATORY BURDEN AND DISEASE ACTIVITY IN ANCA-ASSOCIATED VASCULITIS WITH RENAL INVOLVEMENT

Background:

Predicting clinical outcomes in ANCA-related glomerulonephritis remains a major challenge. To date, there is no reliable biomarker able to predict renal prognosis in patients with ANCA-associated vasculitis (AAV). Micro-RNA (miRNA) are non-coding RNAs involved in the fine tuning of immune cells biology and this epigenetic modulation associates with different phenotypes and prognosis in several diseases.

Objectives:

To investigate the expression of miR-155 and miR-34a in kidney biopsies of AAV patients according with renal outcome.

Methods:

Fifteen patients with AAV and renal involvement (mean age 63.0 ±13.3 years, disease duration 4.9±2.2 months), who underwent renal biopsy. Demographic, clinical and autoimmune parameters were recorded for each patient. Each kidney biopsy was classified according to the Berden Classification, Risk group (according to the ANCA Renal Risk Score) and the chronicity Classification of the Mayo Clinic’s proposed score.

MiR-155 and miR-34a expression was investigated on kidney biopsy tissue using the miRNeasy FFPE kit (Qiagen). The quantitative expression of miR-155, miR-34a and housekeeping gene U1, used as control, was assessed by Real Time-PCR. MiR-155 and miR-34a expression was correlated with histopathological and clinical-laboratory parameters.

Each patient was followed for 12 months and renal outcome was considered according toKDIGO CKDClassification. Markers of inflammation (ESR, CRP) and urine analysis data were recorded at baseline and after 12 months.

Results:

Six (40%) patients were p-ANCA positive and 9 (60%) c-ANCA positive. Eight patients (53%) also had pulmonary involvement. The mean baseline GFR was 30.7±28.8 ml/min/1.73 m2and 10 patients (66%) showed an active urinary sediment.

At disease onset, the mean expression of miR-155 was 9.5±21.1, while the expression of mir-34a was 13.1±46.2. Considering the autoimmune profile, kidney tissue of p-ANCA positive patients was enriched of mir-155 (19.6±30.6 fold) compared to c-ANCA positive patients (1.9±2.9 fold; p=0.001). Particularly, considering the renal function, kidney tissue of patients with greater impairment of renal function (KDIGO stage 5) was enriched of miR-155 (21.5±38.3 fold) compared to patients with less renal impairment (KDIGO stage 1-4) (4.72±8.16 fold, p=0.004).

Tissue expression of miR-155 and miR-34a did not correlated with the abovementioned histopathological classifications.

After 12 months from kidney biopsy, 3(20%) patients had a worsening of renal function, 5 (33%) still presented elevated markers of inflammation and 3 (20%) still had proteinuria at urine analysis. At baseline, kidney tissue of patients with higher CRP plasma levels and proteinuria at follow-up presented higher expression of miR-155 (p=0.002 and p=0.001), whereas no significant differences were found about miR-34a kidney tissue expression.

Conclusion:

MiRNAs may play a potential role in the pathogenesis of ANCA-related glomerulonephritis. MiR-155 kidney enrichment seems to mirror the disease inflammatory burden and activity at the onset and after 12 months representing a possible biomarker in ANCA vasculitis with renal involvement. This finding may represent the basis for further studies on miRNA expression in blood samples, aiming to identify a non-invasive biomarker of kidney damage, predicting disease’s relapses and patients’ prognosis.

References:

[1]Renauer et al, Clin Rev Allergy Immunol. 2016

Disclosure of Interests:

Dario Bruno: None declared, Pier Giacomo Cerasuolo: None declared, Clara Di Mario: None declared, Silvia Laura Bosello Speakers bureau: Abbvie, Pfizer, Boehringer, Laura Gigante: None declared, Alessia Musto: None declared, Gisella Vischini: None declared, Stefano Costanzi: None declared, Stefano Alivernini: None declared, Barbara Tolusso: None declared, Giuseppe Grandaliano: None declared, Elisa Gremese Speakers bureau: Abbvie, BMS, Celgene, Jannsen, Lilly, MSD, Novartis, Pfizer, Sandoz, UCB

FRI0574 RENAL TISSUE EPIGENETIC BIOMARKERS’ CHARACTERIZATION IN PATIENTS WITH LUPUS NEPHRITIS AS PARAMETERS OF DISEASE ACTIVITY, REMISSION AND FLARE

Background:

Epigenetic factors such as non-coding RNA (miRNA) have been shown to be deregulated in Systemic Lupus Erythematosus (SLE). In particular, in mouse model (1), different miRNAs have been associated with lupus nephritis (LN), one of the most severe manifestations of the disease.

Objectives:

The aim of the study was to evaluate the expression of miR-155 and miR-34a in renal tissue as biomarkers of organ involvement and inflammatory tissue activity in patients with LN.

Methods:

Thirty-two LN patients with active renal involvement were enrolled (age: 32.2 ± 9.2 years). The nephritic onset of the disease (early-SLE) was present in 13 patients (41%), while 19 patients (59%) showed a renal involvement during the follow-up (long-SLE). Clinical, laboratory and demographic data were collected for each patient. Disease activity was recorded using SLEDAI-2K and renal activity, using the total SLEDAI-2K fraction including the items related to the renal involvement. Ultrasound-guided renal biopsy has been performed for each patients for the definition of the nephritic class according to the ISN / RPS classification of 2003 revised in 2018(2). The expression of miR-155 and miR-34a in renal tissue was carried out by extraction of total RNA from paraffin-preserved biopsies and after a retrotrascription protocol was evaluated using SYBR® Green-based real-time PCR by relative quantification considering the ΔCt (Ct miRNA- Ct housekeeping gene)(3).

Results:

Mir-155 and miR-34a expression in renal tissue were comparable in the different histological classes. Dividing patients on the base of nephritic onset, patients with early SLE showed lower expression of miR-155 (ΔCt 12.8 ± 10.8) and miR-34a (ΔCt 14.6 ± 9.9) than patients with long-SLE (miR-155: ΔCt 6.1 ± 8.7 p = 0.02; miR-34a: ΔCt 7.1 ± 9.0 p = 0.03). Furthermore, a direct correlation was observed between the expression of miR-155 and miR-34a (r = 0.91, p <0.001). Considering patients with early-SLE, the expression of miR-34a was slightly significant in patients who had relapsed (ΔCt 8.2 ± 11.4 vs ΔCt 18.4 ± 7.9 p = 0.08), although no correlation emerged between the expression of miR-155 and miR-34a both at the time of the biopsy and with the disease activity indices. At the histological evaluation, miR-155 and miR-34a were more expressed in Early-SLE patients who had wire loop lesions (miR-155: ΔCt 19.5 ± 7.7 vs ΔCt 7.3 ± 9.6 p = 0.05; miR-34a: ΔCt 21,7 ± 1.1 vs ΔCt 8,8 ± 9.7 p= 0.05) possibly associated with a greater activation of the inflammatory component.

Conclusion:

MiR-155 and miR-34a may represent tissue biomarkers of inflammatory activation in patients with LN in particular the higher expression of these miRNA in Long-SLE patients could indicate a possible role of these biomarkers in renal involvement in patients with SLE with later renal onset. The increased expression of miR-34a could give indications of a disease recurrence suggesting a closer monitoring of the patient.

References:

[1] Leiss H et al. Plosone 2017

[2] Bajema IM et al Kidney Int. 2018

[3] Alivernini S et al. Nat Commun 2018

Disclosure of Interests:

None declared

SAT0224 ANTIPHOSPHOLIPID ANTIBODIES AND VASCULAR RENAL LESIONS AS PROGNOSTIC FACTORS IN LUPUS NEPHRITIS

Background:

Several studies have showed that antiphospholipid antibodies (aPL) positivity represents a predictor of worse renal outcome in patients with Lupus Nephritis (LN). In addition, an association between aPL positivity and the histological data of vascular lesions on the renal biopsies has been reported.

Objectives:

To determine the prognostic role of aPL and vascular renal lesions in the assessment of clinical outcome during the follow up period, in terms of time to achieve remission, number of renal flares and development of chronic renal damage in patients affected by LN.

Methods:

Among 120 patients affected by LN from our Rheumatology Unit, 91 patients (age 43.8 ± 12 years, 74 (81.3%) female, disease duration 7.1 ± 7.9 years) have been evaluated and the follow-up data have been collected at the baseline and at 6, 12, 24 months and at the last follow-up visit. Histopathological data of 41 patients were evaluated according to the 2016 revision of ISN/RPS classification.

Results:

Among the 91 LN patients, 31 (34.1%) were aPL positive (aPL+), 10 (32.2%) of them were affected by Antiphospholipid Antibodies Syndrome (APS), 53.3% showed a single aPL positivity, 23.1% double aPL positivity and 15.4% triple aPL positivity. At the last follow up visit a significant higher number of aPL+ patients showed a persistent complement consumption than aPL negative (aPL-) patients (p=0.001). Evaluating clinical outcome, we observed that aPL- patients showed a remission achievement time slightly earlier than aPL+ patients (13.6 ± 1.0 months vs 16.5 ± 1.5 months; log-rank test: p=0.06, Breslow test: p=0.08) and as expected, patients with a persistent complement consumption achieve remission later (18.2 ± 1.5 months vs 13.0 ± 1 months; log-rank test: p=0.002, Breslow test: p=0.003). Furthermore at the last follow up, a significant higher percentage of aPL+ patients developed persistent proteinuria (p=0.02) and chronic renal failure (p=0.04). Considering histologic features (activity and chronicity index, glomerulonephritis class, presence of mesangiolysis, glomerular wrinkling, glomerular thrombi, interstitial inflammatory infiltrates, interstitial fibrosis and tubular atrophy,tubulitis and vascular lesions) we didn’t observe significant differences between aPL+ and aPL- patients but we found two typical vascular lesions (mesangiolysis and vascular thrombi) only in aPL + patients.

Conclusion:

aPL positivity is a predictor of worse renal outcome but in our cohort of LN patients we didn’t find an association between aPL positivity and vascular renal lesions at renal biopsy. The worse renal outcome and the late time to achieve remission in aPL+ group can be related to a cumulative vascular damage over time as observed in other organ and systems.

Disclosure of Interests:

None declared

Complement Modulation of Anti-Aging Factor Klotho in Ischemia/Reperfusion Injury and Delayed Graft Function

Klotho is an anti-aging factor mainly produced by renal tubular epithelial cells (TEC) with pleiotropic functions. Klotho is down-regulated in acute kidney injury in native kidney; however, the modulation of Klotho in kidney transplantation has not been investigated. In a swine model of ischemia/reperfusion injury (IRI), we observed a remarkable reduction of renal Klotho by 24 h from IRI. Complement inhibition by C1-inhibitor preserved Klotho expression in vivo by abrogating nuclear factor kappa B (NF-kB) signaling. In accordance, complement anaphylotoxin C5a led to a significant down-regulation of Klotho in TEC in vitro that was NF-kB mediated. Analysis of Klotho in kidneys from cadaveric donors demonstrated a significant expression of Klotho in pre-implantation biopsies; however, patients affected by delayed graft function (DGF) showed a profound down-regulation of Klotho compared with patients with early graft function. Quantification of serum Klotho after 2 years from transplantation demonstrated significant lower levels in DGF patients. Our data demonstrated that complement might be pivotal in the down-regulation of Klotho in IRI leading to a permanent deficiency after years from transplantation. Considering the anti-senescence and anti-fibrotic effects of Klotho at renal levels, we hypothesize that this acquired deficiency of Klotho might contribute to DGF-associated chronic allograft dysfunction.

Multidrug-resistance 1 gene single-nucleotide polymorphisms do not influence long-term graft survival after kidney transplantation

BACKGROUND

The single-nucleotide polymorphisms (SNPs) of the Multidrug resistance 1 (MDR1) gene have been associated with changes in the pharmacokinetics of cyclosporine (CsA) and tacrolimus (FK506). Our aim was investigate the influence of MDR1 SNPs on long-term graft survival in a population of kidney transplant recipients.

METHODS

We retrospectively analyzed 154 patients; they were genotyped for the SNPs C1236T, G2677T/A, and C3435T and evaluated for the influence of those 3 SNPs on CsA or FK506 pharmacokinetics and on long-term graft survival.

RESULTS

Thirty-one patients were wild-type for C1236T, G2677T/A, and C3435T polymorphisms (group A), 76 patients had ≥1 heterozygous mutations (group B), and 47 patients had ≥1 homozygous mutations (group C). CsA-receiving patients in group C needed a significantly higher oral dose than patients in groups B and A (P=.02). No differences in FK506 trough level nor in oral dose taken were observed in FK506-receiving patients. Kaplan-Meier analysis did not show survival differences in the 3 groups, and Cox proportional hazards model confirmed that the MDR1 SNPs did not represent a risk for graft loss.

CONCLUSIONS

Pretransplantation determination of MDR1 SNPs may be helpful to optimize the starting dose of CsA but can not predict long-term graft survival.

Complement-dependent NADPH oxidase enzyme activation in renal ischemia/reperfusion injury

NADPH oxidase plays a central role in mediating oxidative stress during heart, liver, and lung ischemia/reperfusion injury, but limited information is available about NADPH oxidase in renal ischemia/reperfusion injury. Our aim was to investigate the activation of NADPH oxidase in a swine model of renal ischemia/reperfusion damage. We induced renal ischemia/reperfusion in 10 pigs, treating 5 of them with human recombinant C1 inhibitor, and we collected kidney biopsies before ischemia and 15, 30, and 60 min after reperfusion. Ischemia/reperfusion induced a significant increase in NADPH oxidase 4 (NOX-4) expression at the tubular level, an upregulation of NOX-2 expression in infiltrating monocytes and myeloid dendritic cells, and 8-oxo-7,8-dihydro-2'-deoxyguanosine synthesis along with a marked upregulation of NADPH-dependent superoxide generation. This burden of oxidative stress was associated with an increase in tubular and interstitial expression of the myofibroblast marker α-smooth muscle actin (α-SMA). Interestingly, NOX-4 and NOX-2 expression and the overall NADPH oxidase activity as well as α-SMA expression and 8-oxo-7,8-dihydro-2'-deoxyguanosine synthesis were strongly reduced in C1-inhibitor-treated animals. In vitro, when we incubated tubular cells with the anaphylotoxin C3a, we observed an enhanced NADPH oxidase activity and α-SMA protein expression, which were both abolished by NOX-4 silencing. In conclusion, our findings suggest that NADPH oxidase is activated during ischemia/reperfusion in a complement-dependent manner and may play a potential role in the pathogenesis of progressive renal damage in this setting.

Effects of ischemia-reperfusion injury in kidney transplantation: risk factors and early and long-term outcomes in a single center

INTRODUCTION

Ischemia-reperfusion injury (IRI) causes a high rate of delayed graft function (DGF), the most frequent complication in the immediate postoperative period after cadaveric donor kidney transplantation. Herein we evaluated the impact of donor and recipient characteristics on DGF development in terms of the incidence of acute rejection episodes, hospital stay, renal function, and long-term graft and patient survivals.

MATERIALS AND METHODS

Between February 1998 and July 2011, 761 patients underwent cadaveric donor kidney transplantations. DGF was defined as the need for dialysis in the first week. Patients were subdivided according to initial graft function as immediate graft function (IGF) or DGF.

RESULTS

DGF observed in 241 patients (31.6%) was associated independently with expanded criteria donors, extended cold ischemia time, Karpinsky histological score, and prior dialysis duration both univariate and multivariate analysis. The incidence of acute rejection episodes was 18.1% among the DGF group versus 1.3% in the IGF group (P < .01). DGF significantly reduced both graft and patient survivals at 6, 12, 36, and 60 months.

CONCLUSION

DGF was responsible for a longer hospital stay, worse early and long-term renal function, a higher incidence of acute rejection episodes as well as reduced graft and patient survivals.

Advanced age is not an exclusion criterion for kidney transplantation

INTRODUCTION

Renal transplantation in patients older than 60 years has long been regarded with skepticism owing to the increased risk of complications although, as compared with dialysis treatment, a graft seems to improve not only the quality of life but also long-term patient survival. This study sought to analyze the impact of recipient age older than 60 years on patient and graft outcomes.

MATERIALS AND METHODS

We retrospectively investigated the outcomes of 761 kidney transplant recipients from cadaveric donors performed between February 1998 and July 2011. While 69 subjects were at least 60 years of age (group A), 692 were younger than 60 years (group B) at the time of transplantation.

RESULT

Mean follow-up was 60.1 ± 38.5 months. Delayed graft function (DGF) requiring dialysis was observed in 36 group A (52.1%) and 205 group B (29.6%) subjects (P = .001). However, there were also significant differences between group A and group B in terms of mean donor age (60.3 vs 44.6 years; P < .001) and mean donor estimated creatinine clearance (57.8 vs 83.4 mL/min; P < .001). There were no significant differences in death-censored graft survival between the two groups, but elderly patients experienced worse survival (P = .0005). The most common causes of patient death were myocardial infarction, other cardiovascular complications, and tumors.

CONCLUSION

Kidney transplantation is a good option for elderly recipients with end-stage renal disease, providing long graft survival and a good quality of life, although these patients are more likely to develop cancer or cardiovascular disease. Our findings suggested that older patients should not be excluded a priori from transplantation, but meticulous screening for cancer and heart disease should be always be performed to improve outcomes.

Middle and long-term outcomes of dual kidney transplant: a multicenter experience

INTRODUCTION

Dual kidney transplantation (DKTx) to reduce the disparity between demand and supply of organs was evaluated in two Italian centers (Bari and Novara).

MATERIALS AND METHODS

Between October 2000 and October 2011, we performed 97 DKT (26 ipsilateral/71 bilateral) following routine biopsy of all kidneys obtained from expanded criteria donors by Remuzzi-Karpinsky scores. The reference group was 379 single grafts from donors older than 60 years single kidney transplantation ([SKT] × > 60).

RESULTS

Good postoperative renal function was observed in 56 DKTx (57.7%); whereas acute tubular necrosis requiring dialysis was observed in 41 (42.3%) patients. After a mean follow-up of 60 months, DKTx graft survivals were 96%, 93%, and 90% and patient survivals, 96%, 91%, and 91% at 1, 3, and 5 years, respectively. Complications in expanded criteria donor kidney transplantations included a high rate of cytomegalovirus (CMV) disease especially dual kidney cases. DKTx represented the only independent risk factor for CMV disease upon multivariate analysis (odds ratio [OR] 2.33, 95% confidence interval [CI] 1.28-4.2; P = .006). We did not observe any significant difference in graft or patient survival between DKTx and SKTx > 60 years.

CONCLUSIONS

We observed good outcomes up to 5 years after transplantation in terms of graft and patient survival despite the use of inferior grafts. Comparing DKTx and SKT > 60, we noted that the mean Karpinski score for SKTx was significantly better than DKTx, although patient and graft survivals were similar. This trend confirms that the use of a biopsy to allocate expanded criteria donor kidneys may be too protective; therefore, the criteria to select DKTx require further refinement.

Allograft nephrectomy: what is the best surgical technique?

BACKGROUND

The objective of this study was to evaluate differences in outcomes of allograft nephrectomies performed by extracapsular versus intracapsular techniques.

METHODS

From 1993 to 2010, we performed 89 allograft nephrectomies, including 57 by extracapsular techniques and 32 by intracapsular, chosen according to feasibility at the beginning of the surgery. Fisher exact test and logistic regression were used for statistical analysis. Survival estimates after allograft nephrectomy were calculated according to the Kaplan-Meier method.

RESULTS

After a mean graft survival of 49.7 months, the indications for transplant nephrectomy were chronic rejection (39.3%), acute rejection (22.5%), infection/sepsis (19.1%), gross hematuria (6.7%), renal vein thrombosis (6.7%), renal artery thrombosis (3.4%), and graft rupture (2.3%). Mean operative time, blood loss, transfusions, and complications were similar between the extracapsular and intracapsular groups. The only difference in surgical aspects between the 2 groups was the mean hospital stay, which was longer for the extracapsular group (13.8 vs 7.6 days; P = .01), a result that was confirmed by multivariate analysis (odds ratio, 1.05; 95% confidence interval, 1.0-1.1; P = .03).

CONCLUSIONS

Our experience showed no significant advantages in favor of the intracapsular technique except for a shorter length of hospital stay than after the extracapsular procedure.

Rapamycin-induced hypophosphatemia and insulin resistance are associated with mTORC2 activation and Klotho expression

Rapamycin, an immunosuppressive drug used to prevent rejection after kidney transplantation, influences phosphate homeostasis, induces insulin resistance and has been shown to prolong lifespan in animal models. Because Klotho is an aging-suppressor gene controlling phosphate metabolism and insulin sensitivity, we investigated the influence of rapamycin on Klotho expression. A total of 100 kidney transplant recipients, 50 chronically treated with rapamycin and 50 with calcineurin inhibitors, were enrolled; 20 healthy subjects were employed as control. In the rapamycin group, serum phosphate was lower than in the CNI group with an increase in phosphate excretion and a reduction in its reabsorption. In addition, rapamycin increased insulin resistance as shown by HOMA index. Rapamycin treatment of an immortalized proximal tubular cell line induced the expression of Klotho, the phosphorylation of AKT in Ser473, downstream target of mTORC2 and the expression of RICTOR, mTORC2 main component. AKT inhibition reduced the rapamycin-induced expression of Klotho. In vivo rapamycin treatment induced higher degree of RICTOR and AKT Ser(473) expression directly correlating with long-term rapamycin exposure, FE(PO4) and HOMA index. In conclusion, our data would suggest that rapamycin may influence phosphate homeostasis and insulin resistance modulating Klotho expression through mTORC2 activation.

IL-17 expression by tubular epithelial cells in renal transplant recipients with acute antibody-mediated rejection

Acute rejection is still a common complication of kidney transplantation. IL-17 is known to be associated with allograft rejection but the cellular source and the role of this cytokine remains unclear. We investigated IL-17 graft expression in renal transplant recipients with acute antibody-mediated rejection (ABMR), acute T-cell-mediated rejection (TCMR), interstitial fibrosis and tubular atrophy (IFTA) and acute tubular damage due to calcineurin-inhibitor toxicity (CNI). In acute ABMR, tubular IL-17 protein expression was significantly increased compared to TCMR, where most of the IL-17⁺ cells were CD4⁺ graft infiltrating lymphocytes, IFTA and CNI control groups. The tubular expression of IL-17 in acute ABMR colocalized with JAK2 phosphorylation and peritubular capillaries C4d deposition. In addition, IL-17 tubular expression was directly and significantly correlated with the extension of C4d deposits. In cultured proximal tubular cells, C3a induced IL-17 gene and protein expression along with an increased in JAK2 phosphorylation. The inhibition of JAK2 abolished C3a-induced IL-17 expression. The use of steroids and monoclonal antibodies reduced IL-17 expression, JAK2 phosphorylation and C4d deposition in acute ABMR patients. Our data suggest that tubular cells represent a significant source of IL-17 in ABMR and this event might be mediated by the complement system activation featuring this condition.