Background. Resistance to erythropoiesis-stimulating agents (ESAs) is often associated with chronic inflammation. Here, we investigated how anaemia, ESA resistance and the plasma levels of biological markers of inflammation could influence all-cause and cardiovascular disease morbidity and mortality. Methods. Seven hundred and fifty-three haemodialysis (HD) patients (mean age 66 ± 14.2 years, mean dialytic age 70 ± 77 months and diabetes 18.8%) were enrolled and followed-up for 36 months. Demographic, clinical and laboratory data, co-morbidity conditions, administered drugs, all-cause mortality and fatal/non-fatal cardiovascular (CV) events were recorded. We measured ESA resistance index, C-reactive protein (CRP) and interleukin-6 (IL-6). Results. Six hundred and fifty-one patients (86.4%) received ESAs. Patients with haemoglobin level 11 g/dL. ESA resistance values categorized into quartiles (Quartile I 15.4) correlated with all-cause mortality and fatal/non-fatal CV events (RR 1.97, 95% CI 1.392–2.786; RR 1.619, 95% CI 1.123–2.332, respectively). Furthermore, albumin was significantly reduced versus reference patients and correlated with all-cause mortality and CV events; CRP levels were higher in hyporesponders (Quartile IV) (P < 0.001) and predicted all-cause mortality and CV events. IL-6 but not CRP was a strong predictor of ESA resistance. Conclusions. ESA responsiveness can be considered a strong prognostic factor in HD patients and seems to be tightly related to protein-energy wasting and inflammation.
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. 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. 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. 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.
Several experimental models have shown that CXCL10 is required for initiation and development of graft failure caused by both acute and chronic rejection. CXCL10 expression and distribution was investigated in tissue specimens obtained from 22 patients suffering from acute rejection (AR) or chronic allograft nephropathy (CAN) by using in situ hybridization. Furthermore, pretransplantation sera of 316 cadaveric kidney-graft recipients were tested retrospectively for serum CXCL10 levels by a quantitative sandwich immunoassay. Bioptic specimens obtained from patients with CAN were characterized by wide CXCL10 expression not only at level of infiltrating inflammatory cells but also of vascular, tubular, and glomerular structures. In addition, assessment of pretransplant serum CXCL10 levels in 316 graft recipients and stratification of patients in three groups according to serum CXCL10 levels (150 pg/mL, n=84) showed highly significant differences in 5-year survival rates for the two extreme groups (95.7% vs. 79.7%, P=0.0002). Accordingly, patients who developed severe, early AR (277.14±65.08 p=0.004) and those who developed CAN also showed increased pretransplant serum CXCL10 levels (193.2±36.9, P=0.03). Multivariate analysis demonstrated that among the analyzed variables, CXCL10 (relative risk [RR] 2.801) and delayed graft function (RR 3.728) had the highest predictive power of graft loss. These results suggest that pretransplant serum CXCL10 levels greater than 150 pg/mL confer an increased risk of early, severe, AR and subsequent CAN, finally resulting in renal-allograft failure. This finding might be used for the individualization of immunosuppressive therapies.
12 August 2004 in American Journal of Transplantation
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.
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. 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 μg) (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. Fasting Hcy levels markedly decreased in group A after treatment (21.8 [15.5–76.6] μmol/L vs. 9.3 [5.8–13] μmol/L;P <0.0001), whereas no significant changes were observed in group B (20.5 [17–37.6] μmol/L vs. 20.7 [15–34] μmol/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%. Our results demonstrate a beneficial effect of the treatment of hyperhomocysteinemia by vitamin supplementation on cIMT in a group of RTRs.
Background: Oxidative stress is prevalent in dialysis patients and has been implicated in the pathogenesis of cardiovascular disease and anemia. Vitamin E is a fat-soluble antioxidant that plays a central role in reducing lipid peroxidation and inhibiting the generation of reactive oxygen species. The aim of this cross-over randomized study was to compare the effects of a vitamin E-coated polysulfone (Vit E PS) membrane and a non-vitamin E-coated polysulfone (PS) membrane on inflammatory markers and resistance to erythropoietin-stimulating agents (ESAs). Methods: After a 1-month run-in period of standard bicarbonate dialysis with a synthetic membrane, 62 patients of both genders, and older than 18 years, dialysis vintage 48 ± 27 months, BMI 22 ± 3 (from 13 different dialysis units) were randomized (A-B or B-A) in a cross-over design to Vit E PS (treatment A) and to PS (treatment B) both for 6 months. C-reactive protein (CRP) and interleukin-6 (IL-6) concentrations were determined by a sandwich enzyme immunoassay at baseline and every 2 months; red blood cell count, ESA dose and ESA resistance index (ERI) were assessed monthly. Results: Hemoglobin (Hb) levels significantly increased in the Vit E PS group from 11.1 ± 0.6 g/dl at baseline to 11.5 ± 0.7 at 6 months (p < 0.001) and remained unchanged in the PS group. Although ESA dosage remained stable during the observation periods in both groups, ERI was significantly reduced in the Vit E PS group from 10.3 ± 2.2 IU-dl/kg/g Hb week at baseline to 9.2 ± 1.7 at 6 months (p < 0.001). No significant variation of ERI was observed in the PS group. A significant reduction in plasma CRP and IL-6 levels was observed in the Vit E PS group: CRP from 6.7 ± 4.8 to 4.8 ± 2.2 mg/l (p < 0.001) and IL-6 from 12.1 ± 1.4 to 7.5 ± 0.4 pg/ml (p < 0.05). In the PS group, CRP varied from 6.2 ± 4.0 to 6.4 ± 3.7, and IL-6 from 10.6 ± 2.1 to 9.6 ± 3.5 (p = n.s.). Conclusions: Treatment with Vit E PS membranes seems to lead to a reduction in ESA dosage in HD patients; in addition, a low chronic inflammatory response may contribute to a sparing effect on exogenous ESA requirements.