Alberto Rosati

High Pretransplant Serum Levels of CXCL10/IP-10 Are Related to Increased Risk of Renal Allograft Failure

In experimental models, the chemokine CXCL10/IP‐10 is required for graft failure owing to both acute and chronic rejection. In the present study, pretransplantation sera from 316 cadaver kidney graft recipients were tested for serum CXCL10 and CCL22/MDC levels by an ELISA assay. Kidney graft recipients with normally functioning grafts showed significantly lower serum CXCL10 levels than patients who experienced graft failure, whereas no differences for serum CCL22 levels were observed. After the assignment of all patients to four groups according to serum CXCL10 levels, the death‐censored survival rates of grafts were 97.5%, 93.6%, 89.7%, 78.7% (p = 0.0006) at 5 years, while no influence was observed on patient survival. Accordingly, patients with the highest CXCL10 levels showed an increased frequency and severity of rejection episodes. Serum C‐reactive protein (CRP) level was also assayed in the same samples. Increase of serum CRP levels represented a predictive parameter for death, but not for graft failure. Multivariate analysis demonstrated that among the analyzed variables, CXCL10 had the highest predictive power of graft loss (RR 2.787). Thus, measurement of pretransplant serum CXCL10 levels might represent a clinically useful parameter to identify subjects who are at high risk of severe rejection and graft failure.

Vitamin supplementation reduces the progression of atherosclerosis in hyperhomocysteinemic renal-transplant recipients.

Background. We previously demonstrated among renal-transplant recipients (RTRs) a high prevalence of hyperhomocysteinemia, which might account for their elevated cardiovascular risk. The purpose of our study was to document, in hyperhomocysteinemic RTRs, the effect of vitamin supplementation on carotid intima-media thickness (cIMT), which is an early sign of atherosclerosis. Methods. A total of 56 stable hyperhomocysteinemic RTRs were randomly assigned to vitamin supplementation (folic acid 5 mg/day; vitamin B6 50 mg/day; vitamin B12 400 &mgr;g) (group A) or placebo treatment (group B) for 6 months. All subjects underwent cardiovascular risk-factor assessment, including fasting homocysteine (Hcy) levels assay, and high resolution B-mode ultrasound to measure the intima-media thickness of common carotid arteries, at time of enrollment and after 6 months. Results. Fasting Hcy levels markedly decreased in group A after treatment (21.8 [15.5–76.6] &mgr;mol/L vs. 9.3 [5.8–13] &mgr;mol/L;P <0.0001), whereas no significant changes were observed in group B (20.5 [17–37.6] &mgr;mol/L vs. 20.7 [15–34] &mgr;mol/L;P =not significant). In group A, cIMT significantly decreased after treatment (0.95±0.20 mm vs. 0.64±0.17 mm;P <0.0001). All except one patient showed a reduction of cIMT and the mean percentage of cIMT decrease was −32.2±12.9%. Patients with methylenetetrahydrofolate reductase (MTHFR) C677T +/+ genotype, with higher Hcy levels, had the major percentage of decrease of Hcy with respect to the other genotypes (mean decrease: MTHFR +/+ 74.8±5.7%; MTHFR ± 58.1±10%; MTHFR −/− 56.3±8.6%). In hyperhomocysteinemic patients without vitamin supplementation (group B) we documented a significant increase in cIMT after 6 months (0.71±0.16 mm vs. 0.87±0.19 mm;P <0.05). In 19 of 28 subjects we observed an increase in cIMT, and in 9 of 28 the cIMT was unmodified. The mean percentage of cIMT increase was + 23.3±21.1%. Conclusions. Our results demonstrate a beneficial effect of the treatment of hyperhomocysteinemia by vitamin supplementation on cIMT in a group of RTRs.

Estimated one-year glomerular filtration rate is the best predictor of long-term graft function following renal transplant

Background. Long-term success of renal transplantation depends upon the quality of the donor organ, avoidance of peritransplant and early posttransplant damage (rejection), and optimal maintenance of graft function after the first 6–12 months. Glomerular filtration rate (GFR) at 1 year is a standard way to evaluate short-term success, whereas calculated GFR at 5 years gives a better appreciation of long-term outcomes. The objective of this study was to assess the effect of various demographic and transplant-related parameters on renal function via GFR at 1 year and 5 years post transplantation, using univariate and multivariate data analysis. Methods. Data on 1-year GFR were available from 10,397 patients, whereas 2,889 patients provided data on both 1-year and 5-year GFR. All patients were enrolled in the Neoral Multinational Observational Study in Transplantation (Neoral-MOST), an ongoing, prospective, observational study of adult renal transplant recipients. Results. One-year GFR was the most relevant predictor for 5-year GFR. In a multifactorial analysis (ANCOVA) using 1-year GFR as a continuous variable, the effects of several highly relevant parameters from univariate analysis (such as acute rejection and delayed graft function) on 5-year GFR appeared to be fully mediated by their influence on 1-year GFR, whereas immunological risk factors like HLA match or previous transplantation had an ongoing effect on graft function beyond year 1. Conclusions. The findings of this study corroborate and augment data from previous registry surveys, and confirm the importance of observational studies in investigating the role of peritransplant parameters on long-term graft outcome.

Pretransplant serum FT3 levels in kidney graft recipients are useful for identifying patients with higher risk for graft failure

Objective  End‐stage renal disease (ESRD) is a condition associated with thyroid disturbances both in function and morphology. Recent studies demonstrated that serum free triiodothyronine 3 (FT3) levels are negatively correlated with serum markers of inflammation and endothelial activation in patients with ESRD. However, no previous research evaluated serum thyroid function parameters in relation to kidney graft outcome, as we aim to do so in this study.

High cysteine levels in renal transplant recipients: relationship with hyperhomocysteinemia and 5,10-MTHFR polymorphism.

Background. Long-term survival of renal transplant recipients seems to be influenced by the occurrence of thromboembolic complications and cardiovascular disease. Preliminary data available in the literature found high levels of cysteine (Cy) as a risk factor for deep venous thrombosis independently of high homocysteine (tHcy) levels, but no data are available about Cy levels in renal transplant recipients. Methods. To investigate Cy, tHcy, and plasminogen activator inhibitor-1 (PAI-1) levels and the prevalence of 5,10-methylenetetrahydrofolate reductase (MTHFR) in renal transplantation, we studied 70 stable renal transplant recipients and 66 age- and sex-matched normal subjects as controls. Results. Cy, tHcy, and PAI-1 levels were significantly higher in renal transplant recipients with respect to controls (Cy: 254 &mgr;mol/L [117–466] vs. 198 &mgr;mol/L [99–331], P <0.001; tHcy: 17.0 &mgr;mol/L [4.0–68] vs. 8.1 &mgr;mol/L [2.0–24.0], P <0.00001; PAI-1: 16.8 IU/ml [5.1–45.5] vs. 7.9 IU/ml [4.0–18.0], P <0.00001). High Cy levels were detected in 35.8% of patients. Hyperhomocysteinemia, both in the fasting state and postmethionine loading test, was diagnosed in 90% of cases. The odds ratios for Cy and tHcy levels within the fourth quartile with respect to the other quartiles were markedly increased in renal transplant recipients even after adjustment for prevalent cardiovascular risk factors, glomerular filtration rate, tHcy and, Cy, respectively (Cy: 29.0 &mgr;mol/L [95% CI 7.0–111]; tHcy: 29.9 &mgr;mol/L [95% CI 7.5–118.1]). Fasting tHcy levels correlated well with PAI-1 (r =0.65;P <0.0001) but not with Cy levels (r =0.10;P =0.4). The prevalence of the MTHFR 677TT genotype in renal transplant recipients was not significantly higher in patients than in controls (mutant allele frequency: 0.48 in patients and 0.47 in controls) and was associated with significantly higher fasting and postmethionine tHcy levels both in controls and patients. After 2 months of vitamin supplementation, tHcy (Pre: 17.0 &mgr;mol/L [4.0–68]; Post: 7.5 &mgr;mol/L [2.3–21.9];P <0.0001) and PAI-1 levels (Pre: 16.8 IU/ml [5.1–45.5]; Post: 10 IU/ml [2.0–25];P <0.001) were significantly decreased, whereas Cy levels showed a small decrease that did not reach statistical significance (Pre: 254 &mgr;mol/L [117–466]; Post: 209 &mgr;mol/L [168–300];P =0.3). Patients with the MTHFR 677TT genotype had the major percentage of decrease of tHcy levels with respect to the other genotypes. Conclusion. In conclusion, this study demonstrates the presence of elevated Cy plasma levels in renal transplant recipients. Vitamin supplementation reduces tHcy but not Cy levels, and the amount of decrease seems to be influenced by the MTHFR genotype.

High-volume online haemodiafiltration improves erythropoiesis-stimulating agent (ESA) resistance in comparison with low-flux bicarbonate dialysis: results of the REDERT study

BACKGROUND In haemodialysis (HD) patients, anaemia is associated with reduced survival. Despite treatment with erythropoiesis-stimulating agents (ESAs), a large number of patients with chronic kidney disease show resistance to this therapy and require much higher than usual doses of ESAs in order to maintain the recommended haemoglobin (Hb) target, and recent studies suggest that hepcidin (HEP) may mediate the ESA resistance index (ERI). High-volume online haemodiafiltration (HV-OL-HDF) has been shown to improve anaemia and to reduce the need for ESAs in HD patients; this effect is associated with a reduced inflammatory state in these patients. The aim of the REDERT study (role of haemodiafiltration on ERI) was to investigate the effect of different dialysis techniques on ERI and HEP levels in chronic dialysis patients. METHODS A single cross-over, randomized, multicentre study (A-B or B-A) was designed. Forty stable HD patients from seven different dialysis units (male 65%, mean age 67.6 ± 14.7 years and mean dialytic age 48 ± 10 months) were enrolled. Patients were randomized to the standard bicarbonate dialysis (BHD) with low-flux polysulfone (PS) membrane group or to the HV-OL-HDF group with high-flux PS membranes and exchange volume of >20 L/session. After 6 months, patients were shifted to the other dialytic group for a further 6 months. Clinical data, Hb, ESA doses and iron metabolism were recorded every month. HEP, beta2-microglobulin (b2MG) and C-reactive protein (CRP) were determined every 3 months, and ERI was calculated monthly as the weekly ESA dose per kilogram of body weight divided by Hb level. Data were analysed using paired-samples t-test, Wilcoxon signed-rank test and Spearmans correlation coefficient. RESULTS Dialysis efficiency for small molecules assessed as Kt/V was significantly increased in HV-OL-HDF from 1.47 ± 0.24 to 1.49 ± 0.16; P < 0.01. A significant reduction of b2MG was obtained in HV-OL-HDF from month 3 whereas CRP values were not significantly changed during the study period either in BHD or HV-OL-HDF.ERI was significantly reduced in HV-OL-HDF at month 3 and 6 (from 9.1 ± 6.4 UI/weekly/Kg/Hb to 6.7 ± 5.3 UI/weekly/Kg/Hb; P < 0.05) due to a higher ESA consumption in BHD in spite of similar Hb levels. HEP levels were reduced in HV-OL-HDF with respect to BHD after 3 and 6 months. Iron consumption was not significantly different during BHD or HV-OL-HDF treatment as well as transferrin, ferritin and TSAT levels. A significant positive linear correlation between HEP and ERI (r(2) = 0.258, P < 0.001) was observed. CONCLUSIONS In a uraemic patient population with low-grade inflammation treated with HV-OL-HDF, we observed a significant reduction of ERI values as well as HEP levels. The positive correlation between these two parameters supports a role for HEP in the development of ERI in the dialytic population. Moreover, the lower b2MG and the higher Kt/V achieved in HV-OL-HDF confirms the better depurative effect of this technique in comparison with BHD with respect to middle molecules and small-molecular-weight molecules.

Posttransplant Proteinuria Associated With Everolimus

Anti-mTOR may induce proteinuria when utilized after renal transplantation. Little is known about the pathogenesis and composition of proteinuria. To clarify this unresolved aspect, we analyzed urinary protein composition utilizing an integrated proteomics approach, including quantitative assays, 2-dimensional electrophoresis, MALDI-TOF, and Western blots among 48 renal transplant recipients treated with everolimus (EVL; n = 31) or enteric-coated mycophenolic acid (EC-MPA; n = 17). High (>3 g/d) or intermediate levels of proteinuria (1-3 g) developed in 12 EVL patients (39%) compared with 4 subjects (23%) in the EC-MPA group. Proteinuria, which started during the first 2 days after EVL, tended to reduce during the follow-up. Quantitative proteomics showed an increase in low molecular proteins beta2 microglobulin (P < .001) and alpha1 microglobulin (P < .025). Qualitative proteomics showed a marked increase among all urinary components in EVL and EC-MPA patients. Major changes involved typical components of glomerular damage: albumin, Zn-alpha1 glycoprotein, alpha2HS glycoprotein, and leucine-rich alpha2 glycoprotein. In addition, we observed specific biomarkers for EVL: clusters of alpha1-antitrypsin fragments and monoclonal lambda chains. In conclusion, EVL induced proteinuria of a mixed glomerular and tubular origin that correlated with the start of treatment and reached nephrotic ranges in few cases. The specific urinary markers may reflect renal alterations related to the transplant or specific alterations associated with the drug.

Divert to ULTRA: differences in infused volumes and clearance in two on-line hemodiafiltration treatments.

Background: Mixed diffusive-convective dialysis therapies offer greater removal capabilities than conventional dialysis. The aim of this study was to compare two different on-line, post-dilution hemodiafiltration (HDF) treatments with regard to achieved convective volume and middle-molecule dialysis efficiency: standard volume control (sOL-HDF) and automated control of the transmembrane pressure (TMP) (UC-HDF). Methods: We enrolled 30 ESRD patients (55.9 ± 14.0 years, 20/10 M/F) in a randomized, prospective, crossover study. The patients received a 3-month period of sOL-HDF followed by UC-HDF for a further 3 months, or vice versa, using the same dialysis machine. In sOL-HDF, fixed exchange volumes were set according to a filtration fraction greater than or equal to 25%. In UC-HDF therapy, the exchanged volume was driven by a biofeedback system controlling the TMP and its set point in a double loop. Patients maintained their treatment time, dialyzer, blood flow rate, and anticoagulant regimen unchanged throughout the study. Results: Greater convective volumes were achieved in UC-HDF than in sOL-HDF (23.8 ± 3.9 vs.19.8 ± 4.8 L; p<0.001) with high pre-dialysis Ht value (sOL-HDF 34.0 ± 4.5% and UC-HDF 34.0 ± 4.4%; p = 0.91). The average clearance values of β2m and P were higher in UC-HDF than in sOL-HDF (respectively 123 ± 24 vs. 111 ± 22 ml/min, p<0.002 and 158 ± 26 vs. 152 ± 25 ml/min, p<0.05). Moreover, the UC-HDF mode led to a significantly increased rate of call-free sessions from 88% to 97% (p<0.0001). Conclusions: This study showed that the biofeedback module, applied to the automatic control of TMP in on-line HDF, results in higher convective volumes and correspondingly higher β2m and P clearances. By making the HDF treatment more automated and less complex to perform, it significantly reduced the staff workload.

Post-Dilution on Line Haemodiafiltration with Citrate Dialysate: First Clinical Experience in Chronic Dialysis Patients

Background. Citrate has anticoagulative properties and favorable effects on inflammation, but it has the potential hazards of inducing hypocalcemia. Bicarbonate dialysate (BHD) replacing citrate for acetate is now used in chronic haemodialysis but has never been tested in postdilution online haemodiafiltration (OL-HDF). Methods. Thirteen chronic stable dialysis patients were enrolled in a pilot, short-term study. Patients underwent one week (3 dialysis sessions) of BHD with 0.8 mmol/L citrate dialysate, followed by one week of postdilution high volume OL-HDF with standard bicarbonate dialysate, and one week of high volume OL-HDF with 0.8 mmol/L citrate dialysate. Results. In citrate OL-HDF pretreatment plasma levels of C-reactive protein and β2-microglobulin were significantly reduced; intra-treatment plasma acetate levels increased in the former technique and decreased in the latter. During both citrate techniques (OL-HDF and HD) ionized calcium levels remained stable within the normal range. Conclusions. Should our promising results be confirmed in a long-term study on a wider population, then OL-HDF with citrate dialysate may represent a further step in improving dialysis biocompatibility.

Preemptive Cadaveric Renal Transplantation: Fairness and Utility in the Case of High Donation Rate―Pilot Experience of Tuscany Region

Preemptive kidney transplantation is performed before the initiation of chronic dialysis. Preemptive transplantation is the best treatment modality for patients reaching end-stage renal disease. The Tuscany region has experienced, in the last years, a marked increase in donation rate. Starting from 2006, the first Italian cadaveric preemptive transplant program was activated. The aim of our study was to investigate the characteristics and preliminary results of this program. Among 163 patients entered on to the waiting list for renal transplantation from October 2006 to October 2008, 120 (73.6%) were on dialysis for 21.3 +/- 17.8 months, whereas 43 patients (26.4%) had not yet been on dialysis (preemptive). Eighty two patients (50.3%) resided in Tuscany and 81 (49.7) outside Tuscany; 36.6% of Tuscany patients and 16% of extraregional patients (P = .003) were listed as preemptive. Fifty-eight of 163 (35.6%) patients were transplanted during the period after a mean waiting time of 10.3 +/- 6.4 months. The estimated overall man waiting time was 17.5 months (confidence interval (CI) = 15.8-19.2). Upon Cox multivariate analysis, the probability of transplantation was similar for preemptive and dialysed patients (relative risk [RR] 1.02, P = NS). According to local allocation policy, only residents of Tuscany showed a significant advantage in both groups (RR = 0.43, CI = 0.24-0.75, P = .003). Two-year graft and patients survivals were similar, but delayed graft function was lower in the preemptive group (13% vs 42%, P = .007). The 1-year serum creatinine was 1.56 +/- 0.43 in the preemptive group and 1.68 +/- 0.92 in the dialysis group (P = NS). No differences were observed concerning rejection rate. The preemptive listing rate for cadaveric renal transplantation was more than 35% for Tuscany patients.