Alberto Martínez-Castelao

Monocyte subpopulations and cardiovascular risk in chronic kidney disease

Chronic microinflammation and its cellular hallmark, monocyte activation, contribute substantially to the tremendous burden of cardiovascular disease (CVD) in patients with chronic kidney diseases (CKD). Monocyte heterogeneity is widely acknowledged. Cell-surface expression of CD14 and CD16 defines three functionally and phenotypically distinct subsets of monocytes: classical (CD14++CD16−) monocytes, intermediate (CD14++CD16+) monocytes, and nonclassical (CD14+CD16++) monocytes. A growing body of circumstantial evidence suggests that intermediate monocytes, in particular, contribute to the development of atherosclerosis in the general population as well as in patients with CKD. Intermediate monocytes express a unique pattern of chemokine receptors that have been implicated in atherogenesis. Moreover, this subset of monocytes is predisposed to secrete proinflammatory cytokines. Findings from epidemiological studies indicate that numbers of intermediate monocytes increase with worsening renal function, and that high cell counts predict adverse outcomes in patients undergoing dialysis as well as in patients at early stages of CKD. Based on laboratory and clinical data, intermediate monocytes are a promising therapeutic target for CVD in patients with CKD.

Prospective assessment of antidonor cellular alloreactivity is a tool for guidance of immunosuppression in kidney transplantation.

Current characterization of the immune risk in renal transplant patients is only focused on the assessment of preformed circulating alloantibodies; however, alloreactive memory T cells are key players in mediating allograft rejection. Immune monitoring of antidonor alloreactive memory/effector T cells using an IFN-γ Elispot has been shown to distinguish patients at risk for immune-mediated graft dysfunction, suggesting a potential tool for immunosuppression individualization. In this nonrandomized study, we prospectively assessed donor and nondonor T-cell alloreactivity in 60 highly alloreactive patients receiving calcineurin inhibitor-based immunosuppression and in non-T-cell alloreactive transplant recipients treated with a calcineurin inhibitor-free regimen. The impact was evaluated using 1-year allograft outcome. We found a strong association between ongoing antidonor T-cell alloreactivity and histological lesions of acute T cell-mediated rejection in 6-month protocol biopsies, distinguishing those patients with better 1-year graft function, regardless of immunosuppression regimen. Interestingly, evidence for enhanced immune regulation, driven by circulating Foxp3-demethylated regulatory T cells, was only observed among patients achieving antidonor T-cell hyporesponsiveness. Thus, prospective evaluation of donor-specific T-cell sensitization may add crucial information on the alloimmune state of transplanted patients to be used in daily clinical practice.

Clinical usefulness of novel prognostic biomarkers in patients on hemodialysis

Prognosis, risk stratification and monitoring the effects of treatment are fundamental elements in the decision-making process when implementing prevention strategies for chronic kidney disease. The use of biomarkers is increasingly proposed as a method to refine risk stratification and guide therapy. In this Review, we present basic concepts regarding the validation of biomarkers and highlight difficulties inherent to the identification of useful new biomarkers in patients on hemodialysis. We focus on prognostic biomarkers that have been consistently linked to survival in this group of patients. To date, no biomarker has had sufficient full-scale testing to qualify as a useful addition to standard prognostic factors or to guide the prescription of specific treatments in this population. Furthermore, little information exists on the relative strength of various biomarkers for their prediction of mortality. A multimarker approach might refine prognosis in patients on hemodialysis, but this concept needs to be properly evaluated in large longitudinal studies and clinical trials. The potential of proteomics for the identification and study of new biomarkers in the pathophysiology of cardiovascular disease in patients with end-stage renal disease is also discussed.

Immunosuppression for Dual Kidney Transplantation with Marginal Organs: The Old Is Better Yet

Immunosuppressive protocols in dual kidney transplantation (DKT) are based on calcinerurin inhibitors (CNI). We wonder whether a CNI‐free immunosuppression can improve outcome in older patients receiving a DKT with marginal donor organs. Thirty‐six were treated with CsA, MMF and prednisone (CsA group) and 42 with rATG, SRL, MMF and prednisone (SRL group). Incidence of delayed graft function and acute rejection was 44% and 11% in the CsA group, and 40% and 8% in the SRL group. CMV infection incidence was low in both protocols. Three‐year patient survival was 89% in the CsA and 76% in the SRL group. One‐ and 3‐year graft survival after censoring for dead with a functioning allograft was 94.2% and 94% in CsA and 95% and 90% in SRL, respectively. Renal function was similar in both groups whereas proteinuria was higher in the SRL group. Uninephrectomy due to graft thrombosis or urinary‐related complications was numerically higher in the SRL (21%) than in the CsA group (8%) (p = 0.13) and it was associated with renal failure and proteinuria. In DKT, a new induction immunosuppressive protocol based on rATG, SRL, MMF and prednisone does not offer any advantage in comparison to the old CsA, MMF and prednisone.

C.E.R.A. once every 4 weeks in patients with chronic kidney disease not on dialysis: The ARCTOS extension study.

C.E.R.A., a continuous erythropoietin receptor activator is approved for the treatment of anemia in patients with chronic kidney disease (CKD). The ARCTOS (administration of C.E.R.A. in CKD patients to treat anemia with a twice‐monthly schedule) phase 3 study demonstrated the efficacy and safety of C.E.R.A. in correcting anemia when administered once every 2 weeks (Q2W) subcutaneously in patients with CKD not on dialysis. We assessed the feasibility and long‐term safety of converting patients who responded to treatment with C.E.R.A. Q2W to C.E.R.A. once every 4 weeks (Q4W) during a 24‐week extension period. After the core ARCTOS study period (28 weeks), 296 patients entered the 24‐week extension period. At week 29, patients who responded to C.E.R.A. Q2W during the core period were rerandomized to receive subcutaneous C.E.R.A. Q2W or Q4W. Patients in the comparator arm could receive darbepoetin alfa once weekly or Q2W. Dosage was adjusted to maintain hemoglobin (Hb) between 11 and 13 g/dL. Mean Hb levels remained stable in all groups, and were comparable at the end of the extension period (mean [standard deviation], C.E.R.A. Q2W, 11.92 [0.90] g/dL; C.E.R.A. Q4W, 11.70 [0.86] g/dL; darbepoetin alfa, 11.89 [0.98] g/dL). Mean within‐patient standard deviation values for Hb were also comparable in all groups (0.66, 0.62, and 0.65 g/dL for C.E.R.A. Q2W, C.E.R.A. Q4W and darbepoetin alfa, respectively). All treatments were well tolerated. Subcutaneous C.E.R.A. Q4W is safe and effective in maintaining stable Hb levels in patients with CKD not on dialysis following correction with subcutaneous C.E.R.A. Q2W.

Renal protective effect of liposomed superoxide dismutase in an experimental warm ischemia model

Abstract Superoxide dismutdse (SOD) is a potent scavenger of superoxide radicals produced during normothermic ischemia‐reperfusion. Since it has a short half‐life, its optimal effect is achieved when it is given prior to reperfusion. The inclusion of SOD in liposomes (lipo‐OD) prolongs its half‐life (free SOD: 6 min; lipo‐OD: 4 h). The protective effect of lipo‐OD in a 60‐min bilateral renal warm ischemia model was studied. We divided 60 male Wistar rats between two control groups and five study groups according to the drug used (SOD or lipo‐OD) and to the time of SOD administration (prior to ischemia or prior tb reperfusion). SOD and lipo‐OD were both given at 20 mg/kg endovenously. Weight, diuresis, creatinine per 100 g (Cr/100 g), and creatinine clearance per 100 g (CrC1/100 g) were studied. Conventional renal histology was performed after reperfusion and on day 7. Renal malondialdehyde, 6 keto PGF 1 alpha, and TxB2 tissue levels were studi. ed after reperfusion. Results showed that the renal protective effect of free SOD on warm ischemic‐reperfusion injury depended on the time of administration, being more effective when given before reperfusion. On the other hand, the renal protective effect of liposomed SOD did not depend on the time of administration since efficacy was similar when given before reperfusion or before ischemia. The functional protective effect of liposomed SOD was similar to that of free SOD when they were given prior to reperfusion. Nevertheless, since histological damage observed with liposomed SOD was less than with free SOD, it is suggested that the liposomed galenic form may offer better protection against renal warm ischemia. In addition, liposomed SOD was better at preventing tissue prostanoid generatioh after renal warm ischemic‐reperfusion injury than free SOD. We concluded that liposomed SOD shows a higher renal protective effect against warm ischemia than free SOD.

Documento de consenso sobre el manejo de la patología renal en pacientes con infección por VIH

OBJECTIVE To update the 2010 recommendations on the evaluation and management of renal disease in HIV-infected patients. METHODS This document was approved by a panel of experts from the AIDS Working Group (GESIDA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Nephrology (S.E.N.), and the Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC). The quality of evidence and the level of recommendation were evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. RESULTS The basic renal work-up should include measurements of serum creatinine, estimated glomerular filtration rate by CKD-EPI, Urine protein-to-creatinine ratio, and urinary sediment. Tubular function tests should include determination of serum phosphate levels and urine dipstick for glucosuria. In the absence of abnormal values, renal screening should be performed annually. In patients treated with tenofovir or with risk factors for chronic kidney disease (CKD), more frequent renal screening is recommended. In order to prevent disease progression, potentially nephrotoxic antiretroviral drugs are not recommended in patients with CKD or risk factors for CKD. The document advises on the optimal time for referral of a patient to the nephrologist and provides indications for renal biopsy. The indications for and evaluation and management of dialysis and renal transplantation are also addressed. CONCLUSIONS Renal function should be monitored in all HIV-infected patients. The information provided in this document should enable clinicians to optimize the evaluation and management of HIV-infected patients with renal disease.

Online haemodiafiltration improves inflammatory state in dialysis patients: A longitudinal study

Background Patients undergoing conventional hemodialysis (C-HD) present a greater immuno-inflammatory state probably related to uremia, sympathetic nervous system (SNS) activation and /or membrane bioincompatibility, which could improve with a technique-switching to online hemodiafiltration (OL-HD). The antigen-independent pathway activation of this modified immunologic state turns dendritic cells (DC) into an accurate cell model to study these patients. The aim of this study is to further evaluate the immune-inflammatory state of patients in C-HD assessed by DC maturation. Methods 31 patients were submitted to C-HD and after 4 months switched to the OL-HD technique. Monocytes-derived DCs from HD patients were cultured in the presence of IL-4/GM-CSF. DC-maturation was evaluated by assessing the maturation phenotype by flow cytometry (FACs). DCs-functional capacity to elicit T-cell alloresponse was studied by mixed leucocyte reaction. Cytokine release was assessed by FACs and SNS was evaluated measuring renalase levels by ELISA. Results An up-regulation of maturation markers was observed in C-HD DCs which induced two fold more T cells proliferation than OL-HD DCs. Also, C-HD-mDCs presented with over-production of pro-inflammatory cytokines (IL-6, IL-1β, IL-8, IL-10 and TNF-α) compared with OL-HD-mDC (P<0·05). Results were correlated with clinical data. When SNS was evaluated, hypotension events and blood pressure were significantly lower and renalase levels were significantly higher after conversion to OL-HD. Diabetes mellitus type 2 patients also found beneficial reduction of mDC when converted to OL-HD compared to non-diabetics. Conclusions OL-HD could interfere with immuno-inflammatory state in HD patients with an improvement of renalase levels as potential key mediators in the mechanistic pathway of down-regulation of DC maturation.

Consensus document on the management of renal disease in HIV-infected patients.

OBJECTIVE To update the 2010 recommendations on the evaluation and management of renal disease in HIV-infected patients. METHODS This document was approved by a panel of experts from the AIDS Working Group (GESIDA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Nephrology (S.E.N.), and the Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC). The quality of evidence and the level of recommendation were evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. RESULTS The basic renal work-up should include measurements of serum creatinine, estimated glomerular filtration rate by CKD-EPI, Urine protein-to-creatinine ratio, and urinary sediment. Tubular function tests should include determination of serum phosphate levels and urine dipstick for glucosuria. In the absence of abnormal values, renal screening should be performed annually. In patients treated with tenofovir or with risk factors for chronic kidney disease (CKD), more frequent renal screening is recommended. In order to prevent disease progression, potentially nephrotoxic antiretroviral drugs are not recommended in patients with CKD or risk factors for CKD. The document advises on the optimal time for referral of a patient to the nephrologist and provides indications for renal biopsy. The indications for and evaluation and management of dialysis and renal transplantation are also addressed. CONCLUSIONS Renal function should be monitored in all HIV-infected patients. The information provided in this document should enable clinicians to optimize the evaluation and management of HIV-infected patients with renal disease.

Impact of immunosuppressive therapy on arterial stiffness in kidney transplantation: are all treatments the same?

ABSTRACT Arterial stiffness is a biologic process related to ageing and its relationship with cardiovascular risk is well established. Several methods are currently available for non-invasive measurement of arterial stiffness that provide valuable information to further assess patients’ vascular status in real time. In kidney transplantation recipients, several factors could accelerate the stiffness process, such as the use of calcineurin inhibitors (CNIs), the presence of chronic kidney disease and other classical cardiovascular factors, which would explain, at least in part, the high cardiovascular mortality and morbidity. Despite the importance of arterial stiffness as a biomarker of cardiovascular risk, and unlike other cardiovascular risk factors (e.g. left ventricular hypertrophy), only a few clinical trials or retrospective studies of kidney recipients have evaluated its impact. In this review we describe the clinical impact of arterial stiffness as a prognostic marker of cardiovascular disease and the effects of different immunosuppressive regimens on its progression, focusing on the potential benefits of CNI-sparing protocols and supporting the rationale for individualization of immunosuppression in patients with lower arterial elasticity. Among the immunosuppressive drugs, a belatacept-based regimen seems to offer better vascular protection compared with CNIs, although further studies are needed to confirm the preliminary positive results.