Avaluació del filtrat glomerular en candidats a donant renal viu

En una població de pacients candidats a ser donant renal viu, la determinació acurada i precisa de la de la taxa de filtrat glomerular (TFG) és important ja que d’ella en depen que s’accepti o rebutji un canditat a donant renal viu. En aquest estudi es compara la determinació de la TFG calculada segons el mètode isotòpic amb 51Cr-EDTA amb la TFG calculada amb mètodes estimatius basats en substàncies endògenes com la creatinina i la cistatina.

Estimation of glomerular filtration rate in hospitalised patients: are we overestimating renal function?

QUESTIONS UNDER STUDY AND PRINCIPLES: Estimating glomerular filtration rate (GFR) in hospitalised patients with chronic kidney disease (CKD) is important for drug prescription but it remains a difficult task. The purpose of this study was to investigate the reliability of selected algorithms based on serum creatinine, cystatin C and beta-trace protein to estimate GFR and the potential added advantage of measuring muscle mass by bioimpedance. In a prospective unselected group of patients hospitalised in a general internal medicine ward with CKD, GFR was evaluated using inulin clearance as the gold standard and the algorithms of Cockcroft, MDRD, Larsson (cystatin C), White (beta-trace) and MacDonald (creatinine and muscle mass by bioimpedance). 69 patients were included in the study. Median age (interquartile range) was 80 years (73-83); weight 74.7 kg (67.0-85.6), appendicular lean mass 19.1 kg (14.9-22.3), serum creatinine 126 μmol/l (100-149), cystatin C 1.45 mg/l (1.19-1.90), beta-trace protein 1.17 mg/l (0.99-1.53) and GFR measured by inulin 30.9 ml/min (22.0-43.3). The errors in the estimation of GFR and the area under the ROC curves (95% confidence interval) relative to inulin were respectively: Cockcroft 14.3 ml/min (5.55-23.2) and 0.68 (0.55-0.81), MDRD 16.3 ml/min (6.4-27.5) and 0.76 (0.64-0.87), Larsson 12.8 ml/min (4.50-25.3) and 0.82 (0.72-0.92), White 17.6 ml/min (11.5-31.5) and 0.75 (0.63-0.87), MacDonald 32.2 ml/min (13.9-45.4) and 0.65 (0.52-0.78). Currently used algorithms overestimate GFR in hospitalised patients with CKD. As a consequence eGFR targeted prescriptions of renal-cleared drugs, might expose patients to overdosing. The best results were obtained with the Larsson algorithm. The determination of muscle mass by bioimpedance did not provide significant contributions.

Diez años de tratamiento sustitutivo renal en paciente crítico: evolución en el tiempo y factores pronósticos.

El diagnóstic de insuficiència renal aguda (IRA) és complicat, encara i això els estudis mostren incidències elevades de IRA en els pacientes ingressats en UCI respecte a la resta de hospitalitzats. Així mateix la mortalitat del pacient amb IRA en UCI és molt més elevada respecte a la resta de pacients. La gran majoria dels que sobrevisquin presentaran curació complerta de la IRA. L´objectiu del treball és descriure les característiques dels pacients ingressats a la UCI amb IRA que van precisan teràpia reemplaçament renal, analitzar els canvis evolutius dels pacients i el tractament rebut durant els anys passats i determinar els factors de risc associats a mortalitat i recuperació de la funció renal.

Renal responses to three types of renin-angiotensin system blockers in patients with diabetes mellitus on a high-salt diet: a need for higher doses in diabetic patients?

Objective Activation of the renal renin-angiotensin system in patients with diabetes mellitus appears to contribute to the risk of nephropathy. Recently, it has been recognized than an elevation of prorenin in plasma also provides a strong indication of risk of nephropathy. This study was designed to examine renin-angiotensin system control mechanisms in the patient with diabetes mellitus.Methods We enrolled 43 individuals with type 2 diabetes mellitus. All individuals were on a high-salt diet to minimize the contribution of the systemic renin-angiotensin system. After an acute exposure to captopril (25 mg), they were randomized to treatment with either irbesartan (300 mg) or aliskiren (300 mg) for 2 weeks.Results All agents acutely lowered blood pressure and plasma aldosterone, and increased renal plasma flow and glomerular filtration rate. Yet, only captopril and aliskiren acutely increased plasma renin and decreased plasma angiotensin II, whereas irbesartan acutely affected neither renin nor angiotensin II. Plasma renin and angiotensin II subsequently did increase upon chronic irbesartan treatment. When given on day 14, irbesartan and aliskiren again induced the above hemodynamic, renal and adrenal effects, yet without significantly changing plasma renin. Irbesartan at that time did not affect plasma angiotensin II, whereas aliskiren lowered it to almost zero.Conclusion The relative resistance of the renal renin response to acute (irbesartan) and chronic (irbesartan and aliskiren) renin-angiotensin system blockade supports the concept of an activated renal renin-angiotensin system in diabetes, particularly at the level of the juxtaglomerular cell, and implies that diabetic patients might require higher doses of renin-angiotensin system blockers to fully suppress the renal renin-angiotensin system. J Hypertens 29: 2454-2461 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

Circadian regulation of renal function.

Urinary excretion of water and all major electrolytes exhibit robust circadian oscillations. The 24-h periodicity has been well documented for several important determinants of urine formation, including renal blood flow, glomerular filtration, tubular reabsorption, and tubular secretion. Disturbance of the renal circadian rhythms is increasingly recognized as a risk factor for hypertension, polyuria, and other diseases and may contribute to renal fibrosis. The origin of these rhythms has been attributed to the reactive response of the kidney to circadian changes in volume and/or in the composition of extracellular fluids that are entrained by rest/activity and feeding/fasting cycles. However, numerous studies have shown that most of the renal excretory rhythms persist for long periods of time, even in the absence of periodic environmental cues. These observations led to the hypothesis of the existence of a self-sustained mechanism, enabling the kidney to anticipate various predictable circadian challenges to homeostasis. The molecular basis of this mechanism remained unknown until the recent discovery of the mammalian circadian clock made of a system of autoregulatory transcriptional/translational feedback loops, which have been found in all tissues studied, including the kidney. Here, we present a review of the growing evidence showing the involvement of the molecular clock in the generation of renal excretory rhythms.

Renal Services Review 2002 - Consultation Covering Letter (PDF 55 KB)

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Adipocitocinas, inflamación y resistencia insulínica en la insuficiencia renal crónica

: La insuficiencia renal crónica (IRC) condiciona disfunción del tejido adiposo y desequilibrio de las adipocitocinas relacionadas con la inflamación y metabolismo de la glicemia. Objetivo: describir la relación entre los marcadores de inflamación (IL6, TNFα, PCR, RIL2), las adipocitocinas (adiponectina, leptina) y las alteraciones de la glicemia en 336 pacientes con IRC en diferentes grupos de IRC (sin terapia renal sustitutiva, hemodiálisis, diálisis peritoneal). Conclusiones: Pacientes con IRC sin terapia renal sustitutiva, presentan menor estado inflamatorio y adipocitocinas que los pacientes en diálisis. Existe una relación inversa entre adiponectina, inflamación y filtrado glomerular. Las adipocitocinas son un factor de riesgo independiente de hiperglicemia

Lymphomatoid granulomatosis in a renal transplant patient.

Lymphomatoid granulomatosis is a rare angiocentric and angiodestructive pulmonary angiitis considered as a variant of the lymphoproliferative disorder group. Patients with organ transplantation are at an increased risk for post-transplant lymphoproliferative disorders secondary to their immunosuppression. However, lymphomatoid granulomatosis has rarely been described in patients with renal transplantation. It often presents with severe pulmonary signs. We describe a case whose initial presentation was an isolated VIth nerve palsy. We review the radiological and pathological findings and discuss the etiopathogenesis and therapeutic options of this particular lymphoproliferative disorder. With careful and stepwise reduction in her immunosuppression, our patient showed a complete disappearance of her lymphomatoid granulomatosis, and she is clinically well more than 3 years after the diagnosis, with good kidney function.

Evolución de la función renal en un grupo de pacientes con estenosis de la/s arterias renales sometidos a tratamiento medico.

: La elección del tratamiento adecuado para la estenosis aterosclerótica de arterias renales es controvertida. Los ensayos clínicos recientes demuestran que los resultados de la revascularización y el tratamiento farmacológico no son superiores a los del tratamiento con fármacos únicamente por lo que al final de un seguimiento promedio de 4 años, en 49 pacientes en el Servicio de Nefrología del Hospital Valle de Hebrón se consigue una estabilización de la función renal. A pesar de esta buena evolución la mortalidad global y las complicaciones CV siguen siendo muy elevadas.

Renal Services Review 2002

Renal Services Review 2002

Mycophenolic acid formulations in adult renal transplantation - update on efficacy and tolerability.

The description more than 30 years ago of the role of de novo purine synthesis in T and B lymphocytes clonal proliferation opened the possibility for selective immunosuppression by targeting specific enzymatic pathways. Mycophenolic acid (MPA) blocks the key enzyme inosine monophosphate dehydrogenase and the production of guanosine nucleotides required for DNA synthesis. Two MPA formulations are currently used in clinical transplantation as part of the maintenance immunosuppressive regimen. Mycophenolate mofetil (MMF) was the first MPA agent to be approved for the prevention of acute rejection following renal transplantation, in combination with cyclosporine and steroids. Enteric-coated mycophenolate sodium (EC-MPS) is an alternative MPA formulation available in clinical transplantation. In this review, we will discuss the clinical trials that have evaluated the efficacy and safety of MPA in adult kidney transplantation for the prevention of acute rejection and their use in new combination regimens aiming at minimizing calcineurin inhibitor toxicity and chronic allograft nephropathy. We will also discuss MPA pharmacokinetics and the rationale for therapeutic drug monitoring in optimizing the balance between efficacy and safety in individual patients.

Pacientes de edad avanzada con insuficiencia cardíaca ingresados en un servicio de medicina interna: valoración de la función renal.

Objectius: analitzar comorbiditats de pacients hospitalaris ≥65 anys amb Insuficiència Cardíaca (IC). Adequació tractament farmacològic. Impacte Insuficiència Renal (IR). Metodologia: estudi descriptiu transversal de 150 pacients ingressats en Medicina Interna Hospital Vall d'Hebron entre juny'2007-gener'2010. Resultats: hipertensió arterial: 84%; obesitat: 32,1%; cardiopatia isquèmica: 41,3%; fracció d'ejecció del ventricle esquerre (FEVI) conservada: 70%. 53 pacients sense antagonistes de l'enzim convertidor de l'angiotensina, 105 sense βBloquejants i 55 sense antialdosterònics. Prevalença IR: 70%. Factors de risc: HTA, sexe femení. IC+IR+anèmia: 66 pacients, 2 tractament amb eritropoetina. Conclusions: IC de causa hipertensiva, amb FEVI conservada. Mala adequació tractament. Elevada prevalença IR. Importància Síndrome cardiorenal.

Insuficiència renal i mortalitat dels pacients cirròtics amb peritonitis bacteriana espontània i baix risc de mortalitat no tractats amb albúmina

L’expansió amb albúmina disminueix la incidència d’insuficiència renal i la mortalitat dels pacients cirròtics amb peritonitis bacteriana espontània (PBE). Però no està ben establert si caldria administrar-la a tots aquests pacients. Aquest estudi determina la incidència i evolució de la insuficiència renal i mortalitat en una sèrie no seleccionada de pacients cirròtics amb PBE i baix risc de mortalitat (urea&11mmol/l i bilirrubina&68µmol/l) no tractats amb albúmina. La baixa mortalitat i la bona evolució de la funció renal observades en els pacients amb PBE i baix risc de mortalitat no tractats amb albúmina, suggereixen que en aquests pacients no caldria administrar albúmina.

Chronic bradykinin receptor blockade modulates neonatal renal function.

Recent data indicate that bradykinin participates in the regulation of neonatal glomerular function and also acts as a growth regulator during renal development. The aim of the present study was to investigate the involvement of bradykinin in the maturation of renal function. Bradykinin beta2-receptors of newborn rabbits were inhibited for 4 days by Hoe 140. The animals were treated with 300 microg/kg s.c. Hoe 140 (group Hoe, n = 8) or 0.9% NaCl (group control, n = 8) twice daily. Clearance studies were performed in anesthetized rabbits at the age of 8-9 days. Bradykinin receptor blockade did not impair kidney growth, as demonstrated by similar kidney weights in the two groups, nor did it influence blood pressure. Renal blood flow was higher, while renal vascular resistance and filtration fraction were lower in Hoe 140-treated rabbits. No difference in glomerular filtration rate was observed. The unexpectedly higher renal perfusion observed in group Hoe cannot be explained by the blockade of the known vasodilator and trophic effect of bradykinin. Our results indicate that in intact kallikrein-kinin system is necessary for the normal functional development of the kidney.

Efecto del cambio de posición de decúbito supino a decúbito prono en la presión intraabdominal y su relación con la función renal

Es tracta d’un estudi observacional prospectiu en 18 pacients afectats de la síndrome de destret respiratori agut que van requerir un canvi de posició de decúbit supí a decúbit pron per tal de millorar l’oxigenació. La hipòtesi de treball era que aquest canvi de posició podia augmentar la pressió intraabdominal i, en conseqüència, alterar la funció renal per causa prerrenal. Foren registrades variables hemodinàmiques, respiratòries i pressions intrabdominals, i valorada la funció renal. La posició en decúbit pron va produir un augment significatiu de la pressió intraabdominal, però no varem objectivar un descens del filtrat glomerular ni un empitjorament de l’aclariment de creatinina