RESUMEN
BACKGROUND: Mechanisms underlying the pro gression of diabetic kidney disease to ESKD are not fully understood. METHODS: We performed global microRNA (miRNA) analysis on plasma from two cohorts consisting of 375 individuals with type 1 and type 2 diabetes with late diabetic kidney disease, and targeted proteomics analysis on plasma from four cohorts consisting of 746 individuals with late and early diabetic kidney disease. We examined structural lesions in kidney biopsy specimens from the 105 individuals with early diabetic kidney disease. Human umbilical vein endothelial cells were used to assess the effects of miRNA mimics or inhibitors on regulation of candidate proteins. RESULTS: In the late diabetic kidney disease cohorts, we identified 17 circulating miRNAs, represented by four exemplars (miR-1287-5p, miR-197-5p, miR-339-5p, and miR-328-3p), that were strongly associated with 10-year risk of ESKD. These miRNAs targeted proteins in the axon guidance pathway. Circulating levels of six of these proteins-most notably, EFNA4 and EPHA2-were strongly associated with 10-year risk of ESKD in all cohorts. Furthermore, circulating levels of these proteins correlated with severity of structural lesions in kidney biopsy specimens. In contrast, expression levels of genes encoding these proteins had no apparent effects on the lesions. In in vitro experiments, mimics of miR-1287-5p and miR-197-5p and inhibitors of miR-339-5p and miR-328-3p upregulated concentrations of EPHA2 in either cell lysate, supernatant, or both. CONCLUSIONS: This study reveals novel mechanisms involved in progression to ESKD and points to the importance of systemic factors in the development of diabetic kidney disease. Some circulating miRNAs and axon guidance pathway proteins represent potential targets for new therapies to prevent and treat this condition.
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Orientación del Axón/fisiología , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 2/sangre , Nefropatías Diabéticas/etiología , Fallo Renal Crónico/etiología , MicroARNs/sangre , Adulto , Estudios de Cohortes , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 2/complicaciones , Nefropatías Diabéticas/sangre , Femenino , Humanos , Fallo Renal Crónico/sangre , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND AND OBJECTIVES: Intensified immunosuppression in steroid-resistant nephrotic syndrome is broadly applied, with disparate outcomes. This review of patients from the United Kingdom National Study of Nephrotic Syndrome cohort aimed to improve disease stratification by determining, in comprehensively genetically screened patients with steroid-resistant nephrotic syndrome, if there is an association between response to initial intensified immunosuppression and disease progression and/or post-transplant recurrence. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Pediatric patients with steroid-resistant nephrotic syndrome were recruited via the UK National Registry of Rare Kidney Diseases. All patients were whole-genome sequenced, whole-exome sequenced, or steroid-resistant nephrotic syndrome gene-panel sequenced. Complete response or partial response within 6 months of starting intensified immunosuppression was ascertained using laboratory data. Response to intensified immunosuppression and outcomes were analyzed according to genetic testing results, pattern of steroid resistance, and first biopsy findings. RESULTS: Of 271 patients, 178 (92 males, median onset age 4.7 years) received intensified immunosuppression with response available. A total of 4% of patients with monogenic disease showed complete response, compared with 25% of genetic-testing-negative patients (P=0.02). None of the former recurred post-transplantation. In genetic-testing-negative patients, 97% with complete response to first intensified immunosuppression did not progress, whereas 44% of nonresponders developed kidney failure with 73% recurrence post-transplant. Secondary steroid resistance had a higher complete response rate than primary/presumed resistance (43% versus 23%; P=0.001). The highest complete response rate in secondary steroid resistance was to rituximab (64%). Biopsy results showed no correlation with intensified immunosuppression response or outcome. CONCLUSIONS: Patients with monogenic steroid-resistant nephrotic syndrome had a poor therapeutic response and no post-transplant recurrence. In genetic-testing-negative patients, there was an association between response to first intensified immunosuppression and long-term outcome. Patients with complete response rarely progressed to kidney failure, whereas nonresponders had poor kidney survival and a high post-transplant recurrence rate. Patients with secondary steroid resistance were more likely to respond, particularly to rituximab.
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Inmunosupresores/uso terapéutico , Síndrome Nefrótico/tratamiento farmacológico , Síndrome Nefrótico/genética , Rituximab/uso terapéutico , Adolescente , Niño , Preescolar , Ciclofosfamida/uso terapéutico , Ciclosporina/uso terapéutico , Progresión de la Enfermedad , Resistencia a Medicamentos , Femenino , Pruebas Genéticas , Humanos , Terapia de Inmunosupresión/métodos , Lactante , Recién Nacido , Fallo Renal Crónico/etiología , Fallo Renal Crónico/cirugía , Trasplante de Riñón , Masculino , Síndrome Nefrótico/patología , Síndrome Nefrótico/cirugía , Periodo Posoperatorio , Recurrencia , Esteroides , Tacrolimus/uso terapéutico , Resultado del TratamientoAsunto(s)
Enfermedad de Fabry , Enfermedades Renales , Diagnóstico Precoz , Terapia de Reemplazo Enzimático , Enfermedad de Fabry/diagnóstico , Enfermedad de Fabry/epidemiología , Enfermedad de Fabry/genética , Enfermedad de Fabry/terapia , Predisposición Genética a la Enfermedad , Humanos , Isoenzimas/uso terapéutico , Enfermedades Renales/diagnóstico , Enfermedades Renales/epidemiología , Enfermedades Renales/genética , Enfermedades Renales/terapia , Mutación , Fenotipo , Valor Predictivo de las Pruebas , Pronóstico , Proteínas Recombinantes/uso terapéutico , Medición de Riesgo , Factores de Riesgo , alfa-Galactosidasa/genética , alfa-Galactosidasa/uso terapéuticoRESUMEN
The long-term sequelae of AKI have received increasing attention so that its associations with a number of adverse outcomes, including higher mortality and development of CKD, are now widely appreciated. These associations take on particular importance when considering the high incidence of AKI, with a lack of proven interventions and uncertainties around optimal care provision meaning that the long-term sequelae of AKI present a major unmet clinical need. In this review, we examine the published data that inform our current understanding of long-term outcomes following AKI and discuss potential knowledge gaps, covering long-term mortality, CKD, progression to ESKD, proteinuria, cardiovascular events, recurrent AKI, and hospital readmission.
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Lesión Renal Aguda/terapia , Lesión Renal Aguda/diagnóstico , Lesión Renal Aguda/mortalidad , Progresión de la Enfermedad , Humanos , Readmisión del Paciente , Recurrencia , Medición de Riesgo , Factores de Riesgo , Factores de Tiempo , Resultado del TratamientoRESUMEN
BACKGROUND AND OBJECTIVES: Protein carbamylation is a consequence of uremia and carbamylated lipoproteins contribute to atherogenesis in CKD. Proteins can also be carbamylated by a urea-independent mechanism, and whether carbamylated lipoproteins contribute to the progression of CKD has not been investigated. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A case-control study was performed to determine whether there were changes in plasma levels of carbamylated lipoproteins in individuals with type 2 diabetes with eGFR >60 ml/min per 1.73 m2 compared with a group of age- and sex-matched healthy controls. A cohort of 1320 patients with type 2 diabetes with baseline eGFR ≥30 ml/min per 1.73 m2 was longitudinally followed up to evaluate the association between carbamylated lipoproteins and progression of CKD. The primary kidney outcome was defined as doubling of serum creatinine and/or initiation of KRT during follow-up. Plasma carbamylated LDLs and HDLs was measured by ELISA. RESULTS: In individuals with diabetes with eGFR >60 ml/min per 1.73 m2, both plasma carbamylated LDL and HDL levels were higher compared with healthy controls (P<0.001). After a mean follow-up of 9 years of the diabetic cohort, individuals in the top quartile of carbamylated LDL (hazard ratio, 2.21; 95% confidence interval, 1.42 to 3.46; P<0.001) and carbamylated HDL (hazard ratio, 4.53; 95% confidence interval, 2.87 to 7.13; P<0.001) had higher risk of deterioration of kidney function compared with those in the lowest quartile. On multivariable Cox regression analysis, plasma carbamylated LDL was no longer associated with kidney outcome after adjusting for baseline eGFR and potential confounding factors. However, the association between plasma carbamylated HDL and kidney outcome remained significant and was independent of HDL cholesterol. CONCLUSIONS: Plasma carbamylated HDL but not carbamylated LDL was independently associated with progression of CKD in patients with type 2 diabetes.
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Nefropatías Diabéticas/sangre , Lipoproteínas HDL/sangre , Carbamilación de Proteína , Adulto , Anciano , Biomarcadores/sangre , Estudios de Casos y Controles , Creatinina/sangre , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/complicaciones , Nefropatías Diabéticas/diagnóstico , Nefropatías Diabéticas/etiología , Nefropatías Diabéticas/fisiopatología , Progresión de la Enfermedad , Femenino , Tasa de Filtración Glomerular , Humanos , Riñón/fisiopatología , Lipoproteínas LDL/sangre , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
BACKGROUND AND OBJECTIVES: Low eGFR is known to be associated with frailty, but the association between the longitudinal decline of eGFR and incident frailty in older persons remains to be determined. The objective of this study was to investigate whether a fast decline on eGFR would be associated with incident frailty. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Community dwellers, aged ≥70, were included in this secondary analysis of the 5-year Multidomain Alzheimer Preventive Trial (MAPT). eGFR was calculated using CKD-Epidemiology Collaboration equation at baseline and at 6, 12, and 24 months. The lowest quartile of eGFR slope (-4.1 ml/min per 1.73 m2 per yr) defined a fast decline. The frailty phenotype (unintentional weight loss, exhaustion, low physical activity, slow gait, low handgrip strength assessed with a 0-5 score, where higher is worse; a score ≥3 defines frailty) was assessed at baseline, 6, 12, 24, 36, 48, and 60 months. Cox models were used to test the association between fast eGFR decline and incident frailty. RESULTS: A total of 833 participants were frail neither at baseline nor at 2 years and had appropriate follow-up data. Median (IQR) baseline eGFR was 73 (61-84) ml/min per 1.73 m2. Frailty occurred in 95 (11%) participants between 24 and 60 months. Among them, 31/207 (15%) had fast eGFR decline between baseline and 24 months, and 64/626 (10%) did not. In a Cox model adjusted for demographic variables, cardiovascular comorbidity, C-reactive protein, and baseline eGFR, a fast eGFR decline was associated with incident frailty (HR 1.67, 95% CI 1.03 to 2.71). Sensitivity analyses provided consistent findings. CONCLUSIONS: In community-dwelling older adults with relatively preserved baseline eGFR, a fast eGFR decline is associated with incident frailty.
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Fragilidad/fisiopatología , Tasa de Filtración Glomerular , Anciano , Femenino , Humanos , Masculino , Factores de TiempoRESUMEN
BACKGROUND AND OBJECTIVES: Posterior urethral valve is the most common cause of bladder outlet obstruction in infants. We aimed to describe the rate and timing of kidney-related and survival outcomes for children diagnosed with posterior urethral valves in United States children's hospitals using the Pediatric Health Information System database. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This retrospective cohort study included children hospitalized between January 1, 1992 and December 31, 2006, who were in their first year of life, had a diagnosis of congenital urethral stenosis, and underwent endoscopic valve ablation or urinary drainage intervention, or died. Records were searched up to December 31, 2018 for kidney-related mortality, placement of a dialysis catheter, and kidney transplantation. Cox regression analysis was used to identify risk factors, and Kaplan-Meier survival analysis used to determine time-to-event probability. Subgroup survival analysis was performed with outcomes stratified by the strongest identified risk factor. RESULTS: Included were 685 children hospitalized at a median age of 7 (interquartile range, 1-37) days. Thirty four children (5%) died, over half during their initial hospitalization. Pulmonary hypoplasia was the strongest risk factor for death (hazard ratio, 7.5; 95% confidence interval [95% CI], 3.3 to 17.0). Ten-year survival probability was 94%. Fifty-nine children (9%) underwent one or more dialysis catheter placements. Children with kidney dysplasia had over four-fold risk of dialysis catheter placement (hazard ratio, 4.6; 95% CI, 2.6 to 8.1). Thirty-six (7%) children underwent kidney transplant at a median age of 3 (interquartile range, 2-8) years. Kidney dysplasia had a nine-fold higher risk of kidney transplant (hazard ratio, 9.5; 95% CI, 4.1 to 22.2). CONCLUSIONS: Patients in this multicenter cohort with posterior urethral valves had a 5% risk of death, and were most likely to die during their initial hospitalization. Risk of death was higher with a diagnosis of pulmonary hypoplasia. Kidney dysplasia was associated with a higher risk of need for dialysis/transplant. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2019_10_03_CJN04350419.mp3.
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Enfermedades Renales/etiología , Enfermedades Renales/mortalidad , Uretra/anomalías , Estrechez Uretral/congénito , Estrechez Uretral/complicaciones , Estudios de Cohortes , Diagnóstico Precoz , Humanos , Lactante , Recién Nacido , Masculino , Estudios Retrospectivos , Factores de Riesgo , Tasa de Supervivencia , Estrechez Uretral/diagnóstico , Estrechez Uretral/etiologíaRESUMEN
Senescent cells have undergone permanent growth arrest, adopt an altered secretory phenotype, and accumulate in the kidney and other organs with ageing and injury. Senescence has diverse physiologic roles and experimental studies support its importance in nephrogenesis, successful tissue repair, and in opposing malignant transformation. However, recent murine studies have shown that depletion of chronically senescent cells extends healthy lifespan and delays age-associated disease-implicating senescence and the senescence-associated secretory phenotype as drivers of organ dysfunction. Great interest is therefore focused on the manipulation of senescence as a novel therapeutic target in kidney disease. In this review, we examine current knowledge and areas of ongoing uncertainty regarding senescence in the human kidney and experimental models. We summarize evidence supporting the role of senescence in normal kidney development and homeostasis but also senescence-induced maladaptive repair, renal fibrosis, and transplant failure. Recent studies using senescent cell manipulation and depletion as novel therapies to treat renal disease are discussed, and we explore unanswered questions for future research.
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Envejecimiento/fisiología , Senescencia Celular/genética , Senescencia Celular/fisiología , Insuficiencia Renal Crónica/patología , Envejecimiento/genética , Animales , Humanos , Riñón/patología , Riñón/fisiopatología , Ratones , Modelos Animales , Pronóstico , Insuficiencia Renal Crónica/mortalidad , Insuficiencia Renal Crónica/terapiaRESUMEN
Background As children progress to higher stages of AKI, the risk for adverse outcomes dramatically increases. No reliable methods exist to predict AKI progression in hospitalized children. To determine if biomarkers of inflammation and kidney injury can predict AKI progression, we conducted a three-center prospective cohort study of children undergoing cardiopulmonary bypass.Methods On the first day of serum creatinine-defined AKI, we measured urine biomarkers (neutrophil gelatinase-associated lipocalin [NGAL], IL-18, kidney injury molecule 1, liver fatty acid binding protein [L-FABP], albumin, and cystatin C) and plasma biomarkers (IFN, IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, TNF-α, NGAL, and cystatin C). We defined AKI progression as a worsening of AKI stage or persisting stage 3 AKI (≥2 consecutive days).Results In all, 176 of 408 (43%) children developed postoperative AKI. Among the children with AKI, we diagnosed stages 1, 2, and 3 AKI in 145 (82.5%), 25 (14%), and six (3.5%) children, respectively, on the first day of AKI; 28 (7%) children had AKI progression. On the first day of AKI, nine of 17 biomarkers were significantly higher in patients with than without AKI progression. Urine L-FABP (among injury biomarkers) and plasma IL-8 (among inflammatory biomarkers) had the highest discrimination for AKI progression: optimism-corrected area under the curve, 0.70; 95% confidence interval, 0.58 to 0.81 and optimism-corrected area under the curve, 0.80; 95% confidence interval, 0.69 to 0.91, respectively.Conclusions If validated in additional cohorts, plasma IL-8 could be used to improve clinical care and guide enrollment in therapeutic trials of AKI.
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Lesión Renal Aguda/sangre , Lesión Renal Aguda/orina , Progresión de la Enfermedad , Proteínas de Unión a Ácidos Grasos/orina , Interleucina-8/sangre , Lesión Renal Aguda/etiología , Área Bajo la Curva , Biomarcadores/sangre , Biomarcadores/orina , Puente Cardiopulmonar/efectos adversos , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Complicaciones Posoperatorias/sangre , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/orina , Estudios ProspectivosAsunto(s)
Evolución Molecular , Túbulos Renales Proximales/fisiopatología , Proteínas/genética , Proteinuria/genética , Reabsorción Renal , Albúminas/metabolismo , Animales , Humanos , Proteína 2 Relacionada con Receptor de Lipoproteína de Baja Densidad/genética , Proteína 2 Relacionada con Receptor de Lipoproteína de Baja Densidad/metabolismo , Proteínas de la Membrana , Ratones , Proteínas/metabolismo , Proteinuria/fisiopatología , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismoRESUMEN
BACKGROUND AND OBJECTIVES: Hepatitis C virus infection is common in patients with CKD and leads to accelerated progression to ESRD. Sofosbuvir is a potent direct-acting antiviral therapy against hepatitis C virus; however, there are concerns about its safety in patients with CKD. The objective of our study was to determine the safety and efficacy of sofosbuvir in patients with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We studied a retrospective observational cohort of patients with CKD defined by eGFR<60 ml/min per 1.73 m2, ≥30 mg albuminuria per 1 g creatinine, or ≥200 mg proteinuria per 1 g creatinine who received sofosbuvir-based therapy in a large health care system. Regression models were constructed to predict likelihood of sustained virologic response, detect adverse events, and examine changes in eGFR from baseline to follow-up. RESULTS: Ninety-eight patients with CKD (42% stage 1 or 2 CKD and 58% stage 3 CKD) were included. Mean age was 62 years old, 78% were men, and 65% were white. Additionally, 49% of patients had diabetes, 38% of patients had cirrhosis, and 33% of patients had prior solid organ transplant. Overall sustained virologic response was 81% and varied by regimen used and viral genotype. Average baseline eGFR was equivalent to average on-treatment eGFR, but seven patients experienced a rise in creatinine ≥1.5 times baseline while taking sofosbuvir; all but one recovered. In patients with eGFR<60 ml/min per 1.73 m2 at baseline (stage 3 CKD), regression models showed that hepatitis C cure was associated with a 9.3 (95% confidence interval, 0.44 to 18) ml/min per 1.73 m2 improvement in eGFR during the 6-month post-treatment follow-up period. Adverse events were common (81%), but serious adverse events (17%) and treatment discontinuations (8%) were uncommon. CONCLUSIONS: Sofosbuvir-based direct-acting antiviral therapy is safe and effective in a cohort of patients with CKD infected with hepatitis C.
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Antivirales/uso terapéutico , Tasa de Filtración Glomerular/efectos de los fármacos , Hepatitis C/tratamiento farmacológico , Riñón/efectos de los fármacos , Insuficiencia Renal Crónica/complicaciones , Sofosbuvir/uso terapéutico , Anciano , Albuminuria/complicaciones , Albuminuria/fisiopatología , Antivirales/efectos adversos , Quimioterapia Combinada , Femenino , Hepatitis C/complicaciones , Hepatitis C/diagnóstico , Humanos , Riñón/fisiopatología , Masculino , Persona de Mediana Edad , Insuficiencia Renal Crónica/diagnóstico , Insuficiencia Renal Crónica/fisiopatología , Estudios Retrospectivos , Factores de Riesgo , Sofosbuvir/efectos adversos , Respuesta Virológica Sostenida , Factores de Tiempo , Resultado del TratamientoRESUMEN
Glomerular sclerotic lesions develop when the glomerular filtration surface area exceeds the availability of podocyte foot process coverage, but the mechanisms involved are incompletely characterized. We evaluated potential mechanisms using a transgenic (podocin promoter-AA-4E-BP1) rat in which podocyte capacity for hypertrophy in response to growth factor/nutrient signaling is impaired. FSGS lesions resembling human FSGS developed spontaneously by 7 months of age, and could be induced earlier by accelerating kidney hypertrophy by nephrectomy. Early segmental glomerular lesions occurred in the absence of a detectable reduction in average podocyte number per glomerulus and resulted from the loss of podocytes in individual glomerular capillary loops. Parietal epithelial cell division, accumulation on Bowman's capsule, and tuft invasion occurred at these sites. Three different interventions that prevented kidney growth and glomerular enlargement (calorie intake reduction, inhibition of mammalian target of rapamycin complex, and inhibition of angiotensin-converting enzyme) protected against FSGS lesion development, even when initiated late in the process. Ki67 nuclear staining and unbiased transcriptomic analysis identified increased glomerular (but not podocyte) cell cycling as necessary for FSGS lesion development. The rat FSGS-associated transcriptomic signature correlated with human glomerular transcriptomes associated with disease progression, compatible with similar processes occurring in man. We conclude that FSGS lesion development resulted from glomerular growth that exceeded the capacity of podocytes to adapt and adequately cover some parts of the filtration surface. Modest modulation of the growth side of this equation significantly ameliorated FSGS progression, suggesting that glomerular growth is an underappreciated therapeutic target for preservation of renal function.
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Glomeruloesclerosis Focal y Segmentaria/etiología , Glomérulos Renales/crecimiento & desarrollo , Adaptación Fisiológica , Animales , Peso Corporal , Ciclo Celular , Enalapril , Glomeruloesclerosis Focal y Segmentaria/patología , Humanos , Glomérulos Renales/patología , Masculino , Tamaño de los Órganos , Podocitos/fisiología , Distribución Aleatoria , Ratas Endogámicas F344 , Estrés Fisiológico , TranscriptomaRESUMEN
Hematuria is a cardinal symptom in IgA nephropathy, but its influence on the risk of disease progression has been scarcely investigated. We followed a cohort of 112 patients with IgA nephropathy for a mean±SEM period of 14±10.2 years, during which clinical and analytic risk factors (including urine sediment examination) were regularly recorded. According to the magnitude of time-averaged hematuria, we classified patients as those with persistent hematuria and those with negative or minimal hematuria. We also classified patients according to the magnitude of time-averaged proteinuria (>0.75 or ≤0.75 g/d). The proportion of patients reaching ESRD or a 50% reduction of renal function was significantly greater among patients with persistent hematuria than patients with minimal or negative hematuria (30.4% and 37.0% versus 10.6% and 15.2%, respectively; P=0.01). Multivariable analysis revealed time-averaged hematuria, time-averaged proteinuria, renal function at baseline, and the presence of tubulointerstitial fibrosis on renal biopsy as independent predictors of ESRD. After hematuria disappearance, which occurred in 46% of the patients, the rate of renal function decline changed from -6.45±14.66 to -0.18±2.56 ml/min per 1.73 m2 per year (P=0.001). Patients with time-averaged proteinuria >0.75 g/d had significantly poorer renal survival than those with time-averaged proteinuria ≤0.75 g/d. However, on further classification by time-averaged hematuria, only those patients with time-averaged proteinuria >0.75 g/d and persistent hematuria had significantly worse renal survival than those in the other three groups. In conclusion, remission of hematuria may have a significant favorable effect on IgA nephropathy outcomes.
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Glomerulonefritis por IGA/orina , Hematuria/etiología , Riñón/fisiopatología , Adulto , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Glomerulonefritis por IGA/complicaciones , Glomerulonefritis por IGA/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Proteinuria/etiología , Remisión Espontánea , Factores de Riesgo , Adulto JovenRESUMEN
Individuals age >65 years old are the fastest expanding population demographic throughout the developed world. Consequently, more aged patients than before are receiving diagnoses of impaired renal function and nephrosclerosis-age-associated histologic changes in the kidneys. Recent studies have shown that the aged kidney undergoes a range of structural changes and has altered transcriptomic, hemodynamic, and physiologic behavior at rest and in response to renal insults. These changes impair the ability of the kidney to withstand and recover from injury, contributing to the high susceptibility of the aged population to AKI and their increased propensity to develop subsequent progressive CKD. In this review, we examine these features of the aged kidney and explore the various validated and putative pathways contributing to the changes observed with aging in both experimental animal models and humans. We also discuss the potential for additional study to increase understanding of the aged kidney and lead to novel therapeutic strategies.
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Envejecimiento , Riñón/fisiología , Investigación Biomédica/tendencias , Ciclo Celular , Hipoxia de la Célula , Predicción , Humanos , Riñón/citología , Riñón/patología , Riñón/fisiopatología , Masculino , Estrés Oxidativo , Insuficiencia Renal Crónica/etiología , Transducción de SeñalRESUMEN
The cardiac natriuretic peptides (NPs), atrial NP and B-type NP, regulate fluid homeostasis and arterial BP through renal actions involving increased GFR and vascular and tubular effects. Guanylyl cyclase-A (GC-A), the transmembrane cGMP-producing receptor shared by these peptides, is expressed in different renal cell types, including podocytes, where its function is unclear. To study the effects of NPs on podocytes, we generated mice with a podocyte-specific knockout of GC-A (Podo-GC-A KO). Despite the marked reduction of GC-A mRNA in GC-A KO podocytes to 1% of the control level, Podo-GC-A KO mice and control littermates did not differ in BP, GFR, or natriuresis under baseline conditions. Moreover, infusion of synthetic NPs similarly increased the GFR and renal perfusion in both genotypes. Administration of the mineralocorticoid deoxycorticosterone-acetate (DOCA) in combination with high salt intake induced arterial hypertension of similar magnitude in Podo-GC-A KO mice and controls. However, only Podo-GC-A KO mice developed massive albuminuria (controls: 35-fold; KO: 5400-fold versus baseline), hypoalbuminemia, reduced GFR, and marked glomerular damage. Furthermore, DOCA treatment led to decreased expression of the slit diaphragm-associated proteins podocin, nephrin, and synaptopodin and to enhanced transient receptor potential canonical 6 (TRPC6) channel expression and ATP-induced calcium influx in podocytes of Podo-GC-A KO mice. Concomitant treatment of Podo-GC-A KO mice with the TRPC channel blocker SKF96365 markedly ameliorated albuminuria and glomerular damage in response to DOCA. In conclusion, the physiologic effects of NPs on GFR and natriuresis do not involve podocytes. However, NP/GC-A/cGMP signaling protects podocyte integrity under pathologic conditions, most likely by suppression of TRPC channels.
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Riñón/fisiología , Podocitos/fisiología , Receptores del Factor Natriurético Atrial/fisiología , Animales , Femenino , Enfermedades Renales/etiología , Masculino , Ratones , Ratones Noqueados , Podocitos/patología , Canales Catiónicos TRPC/fisiología , Canal Catiónico TRPC6RESUMEN
BACKGROUND: Mast cell activation can lead to nonclassical activation of the Renin-Angiotensin-Aldosterone System. However, the relevance of this to human chronic kidney disease is unknown. We assessed the association between serum tryptase, a product of mast cell activation, and progression to end-stage renal disease or mortality in patients with advanced chronic kidney disease. We stratified patients by use of angiotensin-converting enzyme inhibitors/angiotensin receptor II blockers (ACEi/ARB). MATERIALS AND METHODS: This was a prospective cohort study of 446 participants recruited into the Renal Impairment in Secondary Care study. Serum tryptase was measured at recruitment by sandwich immunoassay. Cox regression analysis was undertaken to determine variables associated with progression to end-stage renal disease or death. RESULTS: Serum tryptase concentration was independently associated with progression to end-stage renal disease but not with death. In patients treated with ACEi or ARB, there was a strong independent association between higher tryptase concentrations and progression to end-stage renal disease; when compared to the lowest tertile, tryptase concentrations in the middle and highest tertiles had hazard ratios [HR] of 5·78 (95% confidence interval [CI] 1·19-28·03, P = 0·029) and 6·19 (95% CI 1·49-25·69, P = 0·012), respectively. The other independent risk factors for progression to end-stage renal disease were lower age, male gender, lower estimated glomerular filtration rate and higher urinary albumin creatinine ratio. CONCLUSION: Elevated serum tryptase concentration is an independent prognostic factor for progression to end-stage renal disease in patients with chronic kidney disease who are receiving treatment with an ACEi or ARB.
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Fallo Renal Crónico/sangre , Insuficiencia Renal Crónica/sangre , Triptasas/sangre , Factores de Edad , Anciano , Albuminuria , Amidohidrolasas/orina , Antagonistas de Receptores de Angiotensina/uso terapéutico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Tasa de Filtración Glomerular , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Sistema Renina-Angiotensina , Riesgo , Factores de Riesgo , Factores SexualesRESUMEN
Recent clinical studies indicate a strong link between AKI and progression of CKD. The increasing prevalence of AKI must compel the nephrology community to consider the long-term ramifications of this syndrome. Considerable gaps in knowledge exist regarding the connection between AKI and CKD. The 13th Acute Dialysis Quality Initiative meeting entitled "Therapeutic Targets of Human Acute Kidney Injury: Harmonizing Human and Experimental Animal Acute Kidney Injury" convened in April of 2014 and assigned a working group to focus on issues related to progression after AKI. This article provides a summary of the key conclusions and recommendations of the group, including an emphasis on terminology related to injury and repair processes for both clinical and preclinical studies, elucidation of pathophysiologic alterations of AKI, identification of potential treatment strategies, identification of patients predisposed to progression, and potential management strategies.
Asunto(s)
Lesión Renal Aguda/complicaciones , Progresión de la Enfermedad , Riñón/patología , Insuficiencia Renal Crónica/etiología , Lesión Renal Aguda/patología , Lesión Renal Aguda/terapia , Animales , Biomarcadores/sangre , Biomarcadores/orina , Puntos de Control del Ciclo Celular , Reparación del ADN , Fibrosis , Humanos , Hipoxia/complicaciones , Mitocondrias/fisiología , Estrés Oxidativo , Insuficiencia Renal Crónica/terapia , Terminología como AsuntoRESUMEN
Evidence suggests that autophagy promotes the development of cellular senescence. Because cellular senescence contributes to renal aging and promotes the progression from AKI to CKD, we investigated the potential effect of tubular autophagy on senescence induction. Compared with kidneys from control mice, kidneys from mice with conditional deletion of autophagy-related 5 (Atg5) for selective ablation of autophagy in proximal tubular S3 segments (Atg5(Δ) (flox/) (Δ) (flox)) presented with significantly less tubular senescence, reduced interstitial fibrosis, and superior renal function 30 days after ischemia/reperfusion injury. To correlate this long-term outcome with differences in the early injury process, kidneys were analyzed 2 hours and 3 days after reperfusion. Notably, compared with kidneys of control mice, Atg5(Δ) (flox/) (Δ) (flox) kidneys showed more cell death in outer medullary S3 segments at 2 hours but less tubular damage and inflammation at day 3. These data suggest that the lack of autophagy prevents early survival mechanisms in severely damaged tubular cells. However, if such compromised cells persist, then they may lead to maladaptive repair and proinflammatory changes, thereby facilitating the development of a senescent phenotype and CKD.
Asunto(s)
Autofagia , Senescencia Celular , Túbulos Renales Proximales/citología , Animales , Masculino , RatonesRESUMEN
The course of autosomal dominant polycystic kidney disease (ADPKD) varies among individuals, with some reaching ESRD before 40 years of age and others never requiring RRT. In this study, we developed a prognostic model to predict renal outcomes in patients with ADPKD on the basis of genetic and clinical data. We conducted a cross-sectional study of 1341 patients from the Genkyst cohort and evaluated the influence of clinical and genetic factors on renal survival. Multivariate survival analysis identified four variables that were significantly associated with age at ESRD onset, and a scoring system from 0 to 9 was developed as follows: being male: 1 point; hypertension before 35 years of age: 2 points; first urologic event before 35 years of age: 2 points; PKD2 mutation: 0 points; nontruncating PKD1 mutation: 2 points; and truncating PKD1 mutation: 4 points. Three risk categories were subsequently defined as low risk (0-3 points), intermediate risk (4-6 points), and high risk (7-9 points) of progression to ESRD, with corresponding median ages for ESRD onset of 70.6, 56.9, and 49 years, respectively. Whereas a score ≤3 eliminates evolution to ESRD before 60 years of age with a negative predictive value of 81.4%, a score >6 forecasts ESRD onset before 60 years of age with a positive predictive value of 90.9%. This new prognostic score accurately predicts renal outcomes in patients with ADPKD and may enable the personalization of therapeutic management of ADPKD.