Posttransplantation anemia: relationship with inflammatory markers, oxidation, and prohepcidin levels.

BACKGROUND: Anemia frequently occurs after kidney transplantation, its origin is multifactorial. The objective of this study was to evaluate the frequency of anemia among kidney transplantation patients at 3 months after transplantation and its relationship to inflammatory, oxidative, and nutritional states. Furthermore, we determined serum prohepcidin, a precursor of hepcidin, the main hormone implicated in iron metabolism. MATERIALS AND METHODS: We performed a transverse retrospective study in 130 patients who underwent kidney transplantation, including 89 men and 41 women. Patients were randomized according to the presence or absence of anemia at 3 months. The patients' inflammatory, oxidative, and nutritional states were evaluated as well as renal function and serum prohepcidin at 3 months. RESULTS: Twenty-four percent of the patients developed anemia at 3 months after transplantation. These patients presented with a greater inflammatory state, a poor nutritional status, and poor renal function. Serum prohepcidin was significantly lower compared with the transplantation patients who did not show anemia. CONCLUSIONS: Serum prohepcidin was significantly higher among kidney transplantation patients who did not develop anemia. The inflammatory state may be a determinant of the response to treatment with erythropoiesis-stimulating agents in anemic kidney transplant recipients.

Posttransplant inflammation associated with onset of chronic kidney disease.

BACKGROUND: Chronic allograft nephropathy (CAN), a major complication in renal transplant patients, is an important cause of graft loss. Inflammation as measured in the pretransplant and posttransplant phases, using various markers, has been associated with worse renal function and a greater risk of cardiovascular disease and of long-term graft loss. OBJECTIVE: The objective of our study was to evaluate whether worsening inflammation in the first 3 months postoperatively was a risk factor for developing CAN. PATIENTS AND METHODS: We performed a cross-sectional study in 207 patients. The following markers of inflammation (MIF) were determined pretransplant and at 3 months after grafting: C-reactive protein (CRP) (mg/L), interleukin (IL)-6 (pg/mL), IL-10 (pg/mL), tumor necrosis factor (TNF)-α (pg/mL), and its soluble receptor (ng/mL), soluble-IL2R (UI/mL), pregnancy-associated plasma protein A (PAPP-A; mUI/L), and IL-4 (pg/mL). We also calculated the ratio at 3 months versus the pre value of MIF. RESULTS: CAN was diagnosed after the first year in 23 patients (11.3%) always by renal biopsy performed for clinical indications. Patients with CAN showed worse inflammation, eg, MIF ratios over one, with statistically significant differences for the ratios of TNF-α and PAPP-A (P=.032 and P=.051 respectively). Upon multivariate logistic regression analysis, using CAN as the dependent variable and age, sex, donor age, months on dialysis, acute tubular necrosis, acute rejection, and MIF ratios as covariates, we observed that an acute rejection episode (OR=13.03; CI=2.8-60.9; P=.001), CRP ratio (OR=1.36; CI=1.07-1.73; P=.013), and PAPP-A ratio (OR=1.80; CI=0.92-3.53; P=.005) were independent markers of CAN. CONCLUSIONS: Among other factors, inflammation may determine the onset of CAN as diagnosed by renal biopsy.

Inflammation, metalloproteinases, and growth factors in the development of carotid atherosclerosis in renal transplant patients.

BACKGROUND: Cardiovascular disease is the leading cause of death in renal transplant (RT) patients. Both traditional and emerging risk factors, some of which are controversial, have been described in the pathogenesis of cardiovascular disease. Carotid ultrasound (CUS) is considered to be an excellent diagnostic tool for subclinical atherosclerosis. OBJECTIVE: To evaluate the relationship between biomarkers of inflammation, growth factors, metalloproteinases, and the development of subclinical atherosclerosis diagnosed by using CUS. METHODS: We studied 93 RT patients (aged 54±12 years; 67.9% men; 13.5% with pre-RT diabetes mellitus). The following biomarkers were determined in the patients' blood hours before RT: C-reactive protein (CRP) and serum amyloid A using nephelometry; interleukin (IL) 2, 6, 8, and 10 and soluble IL-2 receptor, tumor necrosis factor (TNF) α, vascular endothelial growth factor (VEGF), epidermal growth factor, and monocyte chemotactic peptide using chemoluminescence; and pregnancy-associated plasma protein (PAPP)A using ELISA. A CUS was carried out during the first month after RT. RESULTS: Carotid intima-media thickness (IMT) was elevated in 51% of the patients, and 50.5% of the patients had atherosclerotic plaque. Both plaque (P=.004) and IMT (P=.001) correlated with age, and the increase of IMT was progressive, on both the left and the right side. Pre-RT CRP, IL-8, TNF-α, VEGF, MCP-1, and PAPP-A were significantly more elevated in patients with plaque. In the multivariate analysis adjusted for clinical variables, age (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.01-1.10; P=.04), CRP (OR, 7.5; 95% CI, 2.05-27.3; P=.002), IL-8 (OR, 4.73; 95% CI, 1.27-17.6; P=.02), and PAPP-A (OR, 4.45; 95% CI, 1.22-16.2; P=.023) were independent markers of the presence of plaque. CONCLUSIONS: Age, CRP, IL-8, and PAPP-A, and not growth factors, are markers of carotid atheromatous plaque in RT patients.

Hepcidin and iron deficiency in pre-kidney transplant patients.

Hepcidin is a hormone that regulates the intestinal absorption of iron and its release from the reticuloendothelium. The objective of this study was to determine the use of hepcidin for kidney disease patients with a diagnosis of iron deficiency pretransplantation by evaluating the soluble transferrin receptor (sRTfR-F) index as a marker for iron deficiency. This transverse study of 164 pretransplant patients determined hematometry and conventional markers related to iron metabolism, as well as soluble transferrin receptor (sTfR), its index (sTfR-F), and serum hepcidin concentrations. The following markers of inflammation (MIF) were also assessed C-reactive protein (hs-CRP), interleukin-6 (IL-6), soluble IL-2 receptor (sIL-2R), tumor necrosis factor-alpha (TNF-alpha), and soluble TNF-alpha receptor (s-TNF-alphaR). Among the studied patients, 11.4% showed an absolute iron deficiency with ferritin concentrations < 100 ng/mL, a mean hepcidin value of 120.7 +/- 38.5 ng/mL, and a mean sTfR-F value of 1.03 +/- 0.3; 18.2% of patients displayed a ferritin > 800 ng/mL with mean hepcidin and sTfR-F values of 147.5 +/- 36.6 ng/mL and 0.54 +/- 0.2, respectively. Iron deficiency was not observed in the other patients when considering the conventional markers: ferritin > 100 ng/mL and transferrin saturation (ST) > 20%. However, this study showed that determination of hepcidin concentrations together with M/F improved the identification of iron deficiency in pretransplant patients by 21.6%.

Greater posttransplant inflammation and oxidation are associated with worsening kidney function in patients with pretransplant diabetes mellitus.

OBJECTIVE: Patients on dialysis display increased inflammation (IF) and oxidative stress (OS). Diabetes mellitus (DM) may increase both processes. The role of transplantation in this situation is unknown. Herein we have assessed the evolution of IF and OS following grafting and its relationship to a prior diagnoses of DM and to kidney function at 1 year. PATIENTS AND METHODS: This prospective study included 131 dialysis patients who underwent transplantation of mean age 54 +/- 12 years, including 68% men with 19.5% showing prior DM. The following markers of IF and OS were determined prior to and at 3 months after grafting: C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), soluble TNFalpha receptor (sTNFalpha-R), soluble IL-2 receptor (sIL-2R), oxidized LDL (oxLDL), and anti-oxLDL antibodies (oxLDLab). The evolution (ratio) of these markers was assessed by dividing the values at 3 months by the prior ones. Modification of Diet in Renal Disease (MDRD) was determined at 12 months. RESULTS: Patients with prior DM were older (P = .034). There were no differences in the pregrafting phase between diabetics and nondiabetics in relation to IF or OS. IF and OS showed a worse evolution postgrafting among patients with prior DM. At 1 year postgrafting renal function was greater in patients without prior DM (P = .022). There was an inverse correlation between the ratios of markers and kidney function at 1 year postgrafting: TNFalpha: r = -.235 (P = .012); sIL-2R: r = .441 (P < .001); and sTNFalpha-R: r = .225 (P = .017). CONCLUSIONS: In the pregrafting phase, there were no differences between patients with or without DM in terms of IF and OS. These differences appeared in the postgrafting phase: patients with DM showed greater IF and OS, an increase that may explain the poor kidney function observed at 1 year among patients with DM.