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1.
Kidney Int ; 89(1): 167-75, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26759049

RESUMEN

The Oxford Classification of IgA nephropathy (IgAN) includes the following four histologic components: mesangial (M) and endocapillary (E) hypercellularity, segmental sclerosis (S) and interstitial fibrosis/tubular atrophy (T). These combine to form the MEST score and are independently associated with renal outcome. Current prediction and risk stratification in IgAN requires clinical data over 2 years of follow-up. Using modern prediction tools, we examined whether combining MEST with cross-sectional clinical data at biopsy provides earlier risk prediction in IgAN than current best methods that use 2 years of follow-up data. We used a cohort of 901 adults with IgAN from the Oxford derivation and North American validation studies and the VALIGA study followed for a median of 5.6 years to analyze the primary outcome (50% decrease in eGFR or ESRD) using Cox regression models. Covariates of clinical data at biopsy (eGFR, proteinuria, MAP) with or without MEST, and then 2-year clinical data alone (2-year average of proteinuria/MAP, eGFR at biopsy) were considered. There was significant improvement in prediction by adding MEST to clinical data at biopsy. The combination predicted the outcome as well as the 2-year clinical data alone, with comparable calibration curves. This effect did not change in subgroups treated or not with RAS blockade or immunosuppression. Thus, combining the MEST score with cross-sectional clinical data at biopsy provides earlier risk prediction in IgAN than our current best methods.


Asunto(s)
Glomerulonefritis por IGA/clasificación , Glomerulonefritis por IGA/patología , Fallo Renal Crónico/etiología , Riñón/patología , Adulto , Atrofia/patología , Biopsia , Progresión de la Enfermedad , Femenino , Fibrosis , Estudios de Seguimiento , Tasa de Filtración Glomerular , Glomerulonefritis por IGA/fisiopatología , Humanos , Masculino , Células Mesangiales/patología , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico , Medición de Riesgo/métodos
2.
J Am Soc Nephrol ; 26(5): 1216-27, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25381427

RESUMEN

Isolated endarteritis of kidney transplants is increasingly recognized. Notably, microarray studies revealed absence of immunologic signatures of rejection in most isolated endarteritis biopsy samples. We investigated if isolated endarteritis responds to rejection treatment and affects kidney transplant survival. We retrospectively enrolled recipients of kidney transplant who underwent biopsies between 1999 and 2011 at seven American and Canadian centers. Exclusion criteria were recipients were blood group-incompatible or crossmatch-positive or had C4d-positive biopsy samples. After biopsy confirmation, patients were divided into three groups: isolated endarteritis (n=103), positive controls (type I acute T cell-mediated rejection with endarteritis; n=101), and negative controls (no diagnostic rejection; n=103). Primary end points were improved kidney function after rejection treatment and transplant failure. Mean decrease in serum creatinine from biopsy to 1 month after rejection treatment was 132.6 µmol/L (95% confidence interval [95% CI], 78.7 to 186.5) in patients with isolated endarteritis, 96.4 µmol/L (95% CI, 48.6 to 143.2) in positive controls (P=0.32), and 18.6 µmol/L (95% CI, 1.8 to 35.4) in untreated negative controls (P<0.001). Functional improvement after rejection treatment occurred in 80% of patients with isolated endarteritis and 81% of positive controls (P=0.72). Over the median 3.2-year follow-up period, kidney transplant survival rates were 79% in patients with isolated endarteritis, 79% in positive controls, and 91% in negative controls (P=0.01). In multivariate analysis, isolated endarteritis was associated with an adjusted 3.51-fold (95% CI, 1.16 to 10.67; P=0.03) risk for transplant failure. These data indicate that isolated endarteritis is an independent risk factor for kidney transplant failure.


Asunto(s)
Endarteritis/etiología , Trasplante de Riñón/efectos adversos , Adulto , Biopsia , Endarteritis/patología , Endarteritis/terapia , Femenino , Rechazo de Injerto/terapia , Supervivencia de Injerto , Humanos , Riñón/patología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos
3.
Kidney Int ; 80(3): 310-7, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21544062

RESUMEN

The Oxford classification of IgA nephropathy (IgAN) identified four pathological elements that were of prognostic value and additive to known clinical and laboratory variables in predicting patient outcome. These features are segmental glomerulosclerosis/adhesion, mesangial hypercellularity, endocapillary proliferation, and tubular atrophy/interstitial fibrosis. Here, we tested the Oxford results using an independent cohort of 187 adults and children with IgAN from 4 centers in North America by comparing the performance of the logistic regression model and the predictive value of each of the four lesions in both data sets. The cohorts had similar clinical and histological findings, presentations, and clinicopathological correlations. During follow-up, however, the North American cohort received more immunosuppressive and antihypertensive therapies. Identifying patients with a rapid decline in the rate of renal function using the logistic model from the original study in the validation data set was good (c-statistic 0.75), although less precise than in the original study (0.82). Individually, each pathological variable offered the same predictive value in both cohorts except mesangial hypercellularity, which was a weaker predictor. Thus, this North American cohort validated the Oxford IgAN classification and supports its utilization. Further studies are needed to determine the relationship to the impact of treatment and to define the value of the mesangial hypercellularity score.


Asunto(s)
Glomerulonefritis por IGA/clasificación , Glomerulonefritis por IGA/diagnóstico , Riñón/patología , Terminología como Asunto , Adolescente , Adulto , Análisis de Varianza , Antihipertensivos/uso terapéutico , Atrofia , Biopsia , Canadá , Capilares/patología , Distribución de Chi-Cuadrado , Femenino , Fibrosis , Tasa de Filtración Glomerular , Glomerulonefritis por IGA/tratamiento farmacológico , Glomerulonefritis por IGA/patología , Glomerulonefritis por IGA/fisiopatología , Glomeruloesclerosis Focal y Segmentaria/diagnóstico , Glomeruloesclerosis Focal y Segmentaria/patología , Humanos , Inmunosupresores/uso terapéutico , Riñón/efectos de los fármacos , Riñón/fisiopatología , Análisis de los Mínimos Cuadrados , Modelos Logísticos , Masculino , Células Mesangiales/patología , Persona de Mediana Edad , Oportunidad Relativa , Valor Predictivo de las Pruebas , Pronóstico , Modelos de Riesgos Proporcionales , Reproducibilidad de los Resultados , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Factores de Tiempo , Estados Unidos , Adulto Joven
4.
Kidney Int ; 79(8): 914-20, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21248713

RESUMEN

Advances in immunotherapy have improved survival of patients with systemic lupus erythematosus who now face an increasing burden of chronic diseases including that of the kidney. As systemic inflammation is also thought to contribute directly to the progression of chronic kidney disease (CKD), we assessed this risk in patients with lupus, with and without a diagnosis of nephritis, and also identified modifiable risk factors. Accordingly, we enrolled 631 patients (predominantly Caucasian), of whom 504 were diagnosed with lupus within the first year and followed them an average of 11 years. Despite the presence of a chronic inflammatory disease, the rate of decline in renal function of 238 patients without nephritis was similar to that described for non-lupus patient cohorts. Progressive loss of kidney function developed exclusively in patients with lupus nephritis who had persistent proteinuria and dyslipidemia, although only six required dialysis or transplantation. The mortality rate was 16% with half of the deaths attributable to sepsis or cancer. Thus, despite the presence of a systemic inflammatory disease, the risk of progressive CKD in this lupus cohort was relatively low in the absence of nephritis. Hence, as in idiopathic glomerular disease, persistent proteinuria and dyslipidemia (modifiable risks) are the major factors for CKD progression in lupus patients with renal involvement.


Asunto(s)
Dislipidemias/complicaciones , Lupus Eritematoso Sistémico/complicaciones , Proteinuria/complicaciones , Insuficiencia Renal Crónica/etiología , Adulto , Anciano , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Tasa de Filtración Glomerular , Humanos , Estimación de Kaplan-Meier , Lupus Eritematoso Sistémico/mortalidad , Lupus Eritematoso Sistémico/fisiopatología , Nefritis Lúpica/etiología , Nefritis Lúpica/fisiopatología , Masculino , Persona de Mediana Edad , Ontario/epidemiología , Estudios Prospectivos , Insuficiencia Renal Crónica/mortalidad , Insuficiencia Renal Crónica/fisiopatología , Factores de Riesgo , Adulto Joven
5.
Am J Pathol ; 177(5): 2290-9, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20889563

RESUMEN

SLK expression and activity are increased during kidney development and recovery from renal ischemia-reperfusion injury. In cultured cells, SLK promotes F-actin destabilization as well as apoptosis, partially via the p38 kinase pathway. To better understand the effects of SLK in vivo, a transgenic mouse model was developed where SLK was expressed in a podocyte-specific manner using the mouse nephrin promoter. Offspring of four founder mice carried the SLK transgene. Among male transgenic mice, 66% developed albuminuria at approximately 3 months of age, and the albuminuric mice originated from three of four founders. Overall, the male transgenic mice demonstrated about fivefold greater urinary albumin/creatinine compared with male non-transgenic mice. Transgenic and non-transgenic female mice did not develop albuminuria, suggesting that females were less susceptible to glomerular filtration barrier damage than their male counterparts. In transgenic mice, electron microscopy revealed striking podocyte injury, including poorly formed or effaced foot processes, and edematous and vacuolated cell bodies. By immunoblotting, nephrin expression was decreased in glomeruli of the albuminuric transgenic mice. Activation-specific phosphorylation of p38 was increased in transgenic mice compared with non-transgenic animals. Glomeruli of SLK transgenic mice showed around 30% fewer podocytes, and a reduction in F-actin compared with control glomeruli. Thus, podocyte SLK overexpression in vivo results in injury and podocyte loss, consistent with the effects of SLK in cultured cells.


Asunto(s)
Albuminuria/metabolismo , Podocitos/enzimología , Podocitos/patología , Proteínas Serina-Treonina Quinasas/metabolismo , Actinina/genética , Actinina/metabolismo , Animales , Citoesqueleto/metabolismo , Femenino , Humanos , Glomérulos Renales/citología , Glomérulos Renales/metabolismo , Glomérulos Renales/patología , Masculino , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Ratones Transgénicos , Podocitos/ultraestructura , Proteínas Serina-Treonina Quinasas/genética , Transgenes , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
6.
Kidney Int ; 78(5): 463-72, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20531451

RESUMEN

The progressive decline in kidney function and concomitant loss of renal 1alpha-hydroxylase (CYP27B1) in chronic kidney disease (CKD) are associated with a gradual loss of circulating 25-hydroxyvitamin D(3) (25(OH)D(3)) and 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)). However, only the decrease in 1alpha,25(OH)(2)D(3) can be explained by the decline of CYP27B1, suggesting that insufficiency of both metabolites may reflect their accelerated degradation by the key catabolic enzyme 24-hydroxylase (CYP24). To determine whether CYP24 is involved in causing vitamin D insufficiency and/or resistance to vitamin D therapy in CKD, we determined the regulation of CYP24 and CYP27B1 in normal rats and rats treated with adenine to induce CKD. As expected, CYP24 decreased whereas CYP27B1 increased when normal animals were rendered vitamin D deficient. Unexpectedly, renal CYP24 mRNA and protein expression were markedly elevated, irrespective of the vitamin D status of the rats. A significant decrease in serum 1alpha,25(OH)(2)D(3) levels was found in uremic rats; however, we did not find a coincident decline in CYP27B1. Analysis in human kidney biopsies confirmed the association of elevated CYP24 with kidney disease. Thus, our findings suggest that dysregulation of CYP24 may be a significant mechanism contributing to vitamin D insufficiency and resistance to vitamin D therapy in CKD.


Asunto(s)
Riñón/metabolismo , Uremia/metabolismo , Vitamina D/metabolismo , 25-Hidroxivitamina D3 1-alfa-Hidroxilasa/análisis , 25-Hidroxivitamina D3 1-alfa-Hidroxilasa/genética , Animales , Calcitriol/farmacología , Inmunohistoquímica , Masculino , ARN Mensajero/análisis , Ratas , Ratas Sprague-Dawley , Esteroide Hidroxilasas/análisis , Esteroide Hidroxilasas/genética , Vitamina D3 24-Hidroxilasa
7.
Kidney Int ; 77(10): 921-7, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20200498

RESUMEN

To study the predictive value of biopsy lesions in IgA nephropathy in a range of patient ages we retrospectively analyzed the cohort that was used to derive a new classification system for IgA nephropathy. A total of 206 adults and 59 children with proteinuria over 0.5 g/24 h/1.73 m(2) and an eGFR of stage-3 or better were followed for a median of 69 months. At the time of biopsy, compared with adults children had a more frequent history of macroscopic hematuria, lower adjusted blood pressure, and higher eGFR but similar proteinuria. Although their outcome was similar to that of adults, children had received more immunosuppressants and achieved a lower follow-up proteinuria. Renal biopsies were scored for variables identified by an iterative process as reproducible and independent of other lesions. Compared with adults, children had significantly more mesangial and endocapillary hypercellularity, and less segmental glomerulosclerosis and tubulointerstitial damage, the four variables previously identified to predict outcome independent of clinical assessment. Despite these differences, our study found that the cross-sectional correlation between pathology and proteinuria was similar in adults and children. The predictive value of each specific lesion on the rate of decline of renal function or renal survival in IgA nephropathy was not different between children and adults.


Asunto(s)
Glomerulonefritis por IGA/clasificación , Glomerulonefritis por IGA/patología , Adulto , Biopsia , Niño , Enfermedad Crónica , Femenino , Glomerulonefritis/clasificación , Glomerulonefritis/patología , Hematuria/clasificación , Hematuria/patología , Humanos , Inmunosupresores/clasificación , Riñón/patología , Pruebas de Función Renal , Masculino , Proteinuria/clasificación , Proteinuria/patología
8.
J Am Soc Nephrol ; 20(6): 1223-35, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19406980

RESUMEN

The balance of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) determines the integrity of the extracellular matrix. TIMP3 is the most highly expressed tissue inhibitor of metalloproteinase (TIMP) in the kidney, but its function in renal disease is incompletely understood. In this study, TIMP3-/- mice demonstrated an age-dependent chronic tubulointerstitial fibrosis. After unilateral ureteral obstruction (UUO), young TIMP3-/- mice exhibited increased renal injury (tubular atrophy, cortical and medullary thinning, and vascular damage) compared with wild-type mice. In addition, TIMP3-/- mice had greater interstitial fibrosis; increased synthesis and deposition of type I collagen; increased activation of fibroblasts; enhanced apoptosis; and greater activation of MMP2, but not MMP9, after UUO. TIMP3 deficiency also led to accelerated processing of TNFalpha, demonstrated by significantly higher TACE activity and greater soluble TNFalpha levels by 3 d after UUO. The additional deletion of TNFalpha markedly reduced inflammation, apoptosis, and induction of a number of MMPs. Moreover, inhibition of MMPs in TIMP3-/-/TNFalpha-/- mice further abrogated postobstructive injury and prevented tubulointerestitial fibrosis. In humans, TIMP3 expression increased in the renal arteries and proximal tubules of subjects with diabetic nephropathy or chronic allograft nephropathy. Taken together, these results provide evidence that TIMP3 is an important mediator of kidney injury, and regulating its activity may have therapeutic benefit for patients with kidney disease.


Asunto(s)
Nefritis Intersticial/metabolismo , Inhibidor Tisular de Metaloproteinasa-3/metabolismo , Anciano , Envejecimiento/fisiología , Animales , Apoptosis , Estudios de Casos y Controles , Nefropatías Diabéticas/metabolismo , Matriz Extracelular/metabolismo , Femenino , Fibrosis , Rechazo de Injerto/metabolismo , Humanos , Riñón/patología , Sistema de Señalización de MAP Quinasas , Masculino , Metaloproteinasas de la Matriz/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Persona de Mediana Edad , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Obstrucción Ureteral
9.
J Am Soc Nephrol ; 20(4): 730-41, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19211714

RESUMEN

Excessive reactive oxygen species play a key role in the pathogenesis of diabetic nephropathy, but to what extent these result from increased generation, impaired antioxidant systems, or both is incompletely understood. Here, we report the expression, localization, and activity of the antioxidant thioredoxin and its endogenous inhibitor thioredoxin interacting protein (TxnIP) in vivo and in vitro. In normal human and rat kidneys, expression of TxnIP mRNA and protein was most abundant in the glomeruli and distal nephron (distal convoluted tubule and collecting ducts). In contrast, thioredoxin mRNA and protein localized to the renal cortex, particularly within the proximal tubules and to a lesser extent in the distal nephron. Induction of diabetes in rats increased expression of TxnIP but not thioredoxin mRNA. Kidneys from patients with diabetic nephropathy had significantly higher levels of TxnIP than control kidneys, but thioredoxin expression did not differ. In vitro, high glucose increased TxnIP expression in mesangial, NRK (proximal tubule), and MDCK (distal tubule/collecting duct) cells, and decreased the expression of thioredoxin in mesangial and MDCK cells. Knockdown of TxnIP with small interference RNA suggested that TxnIP mediates the glucose-induced impairment of thioredoxin activity. Knockdown of TxnIP also abrogated both glucose-induced 3H-proline incorporation (a marker of collagen production) and oxidative stress. Taken together, these findings suggest that impaired thiol reductive capacity contributes to the generation of reactive oxygen species in diabetes in a site- and cell-specific manner.


Asunto(s)
Diabetes Mellitus Experimental/fisiopatología , Nefropatías Diabéticas/fisiopatología , Tiorredoxinas/fisiología , Animales , Línea Celular , Nefropatías Diabéticas/genética , Perros , Femenino , Riñón/fisiología , Túbulos Renales Colectores/fisiología , Túbulos Renales Proximales/fisiología , ARN Mensajero/genética , Ratas , Valores de Referencia , Tiorredoxinas/genética
10.
Kidney Int ; 76(5): 546-56, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19571790

RESUMEN

Pathological classifications in current use for the assessment of glomerular disease have been typically opinion-based and built on the expert assumptions of renal pathologists about lesions historically thought to be relevant to prognosis. Here we develop a unique approach for the pathological classification of a glomerular disease, IgA nephropathy, in which renal pathologists first undertook extensive iterative work to define pathologic variables with acceptable inter-observer reproducibility. Where groups of such features closely correlated, variables were further selected on the basis of least susceptibility to sampling error and ease of scoring in routine practice. This process identified six pathologic variables that could then be used to interrogate prognostic significance independent of the clinical data in IgA nephropathy (described in the accompanying article). These variables were (1) mesangial cellularity score; percentage of glomeruli showing (2) segmental sclerosis, (3) endocapillary hypercellularity, or (4) cellular/fibrocellular crescents; (5) percentage of interstitial fibrosis/tubular atrophy; and finally (6) arteriosclerosis score. Results for interobserver reproducibility of individual pathological features are likely applicable to other glomerulonephritides, but it is not known if the correlations between variables depend on the specific type of glomerular pathobiology. Variables identified in this study withstood rigorous pathology review and statistical testing and we recommend that they become a necessary part of pathology reports for IgA nephropathy. Our methodology, translating a strong evidence-based dataset into a working format, is a model for developing classifications of other types of renal disease.


Asunto(s)
Glomerulonefritis por IGA/clasificación , Glomerulonefritis por IGA/patología , Riñón/patología , Biopsia , Humanos , Células Mesangiales/patología , Necrosis , Reproducibilidad de los Resultados
11.
Kidney Int ; 76(5): 534-45, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19571791

RESUMEN

IgA nephropathy is the most common glomerular disease worldwide, yet there is no international consensus for its pathological or clinical classification. Here a new classification for IgA nephropathy is presented by an international consensus working group. The goal of this new system was to identify specific pathological features that more accurately predict risk of progression of renal disease in IgA nephropathy, thus enabling both clinicians and pathologists to improve individual patient prognostication. In a retrospective analysis, sequential clinical data were obtained on 265 adults and children with IgA nephropathy who were followed for a median of 5 years. Renal biopsies from all patients were scored by pathologists blinded to the clinical data for pathological variables identified as reproducible by an iterative process. Four of these variables: (1) the mesangial hypercellularity score, (2) segmental glomerulosclerosis, (3) endocapillary hypercellularity, and (4) tubular atrophy/interstitial fibrosis were subsequently shown to have independent value in predicting renal outcome. These specific pathological features withstood rigorous statistical analysis even after taking into account all clinical indicators available at the time of biopsy as well as during follow-up. The features have prognostic significance and we recommended they be taken into account for predicting outcome independent of the clinical features both at the time of presentation and during follow-up. The value of crescents was not addressed due to their low prevalence in the enrolled cohort.


Asunto(s)
Glomerulonefritis por IGA/clasificación , Glomerulonefritis por IGA/patología , Riñón/patología , Adolescente , Adulto , Anciano , Biopsia , Niño , Preescolar , Femenino , Tasa de Filtración Glomerular , Glomerulonefritis por IGA/etnología , Glomerulonefritis por IGA/fisiopatología , Humanos , Glomérulos Renales/patología , Masculino , Persona de Mediana Edad
12.
Am J Kidney Dis ; 54(3): 533-7, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19376619

RESUMEN

Inflammatory myofibroblastic tumor, or inflammatory pseudotumor, usually is a benign lesion composed of mixed inflammatory and fibroblastic elements. It has rarely been reported in the posttransplantation setting and never in association with a renal allograft. Although the pathogenesis of this lesion is unclear, exposure to immunosuppressive agents and various infections have been implicated in its development. We report the first case of inflammatory myofibroblastic tumor infiltrating a renal allograft and highlight the role immunosuppression may have in the development of this lesion.


Asunto(s)
Granuloma de Células Plasmáticas/diagnóstico , Granuloma de Células Plasmáticas/patología , Enfermedades Renales/diagnóstico , Enfermedades Renales/patología , Trasplante de Riñón/efectos adversos , Trasplante de Riñón/patología , Femenino , Granuloma de Células Plasmáticas/etiología , Humanos , Enfermedades Renales/etiología , Persona de Mediana Edad , Trasplante Homólogo
13.
Semin Diagn Pathol ; 26(2): 89-102, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19891303

RESUMEN

Vasculitis refers to vessel wall leukocyte infiltration, often with necrosis, and can involve any of one or more vessels in the body. The kidney is commonly affected by vasculitis. Vasculitis is best classified based on the size of the involved vessels into large, medium, and small vessel disease. Small vessel vasculitis (SVV) that includes glomerulonephritis is by far the most frequent vasculitic lesion in the kidney, and the defining renal lesion is a necrotizing crescentic glomerulonephritis. Medium vessel vasculitis occasionally involves the kidney as necrotizing arteritis, and large vessel vasculitis only rarely affects the kidney, and most often secondarily by ischemia from proximal arterial narrowing. In this review, we describe the clinical and pathologic features of the various vasculitides that affect the kidney, with emphasis on SVV, particularly the type that is associated with anti-neutrophilic cytoplasmic antibodies (ANCA). We will also discuss the relevance of ANCA and describe evidence supporting the pathogenic role of these antibodies. It is important to remember that a histopathologic vasculitic lesion can be shared by several vasculitides, so that clinical data are most often required for disease classification.


Asunto(s)
Enfermedades Renales/diagnóstico , Vasculitis/diagnóstico , Animales , Anticuerpos Anticitoplasma de Neutrófilos/inmunología , Humanos , Riñón/irrigación sanguínea , Riñón/patología , Enfermedades Renales/etiología , Vasculitis/etiología
14.
Kidney Int ; 74(12): 1610-6, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19034303

RESUMEN

Angiotensin converting enzyme (ACE) generates angiotensin II from angiotensin I, which plays a critical role in the pathophysiology of diabetic nephropathy. However, ACE2 generates angiotensin 1-7, which may protect the kidney by attenuating the effects of angiotensin II, since deletion of the Ace2 gene leads to glomerulosclerosis in mice, and pharmacologic inhibition of ACE2 exacerbates experimental diabetic nephropathy. We measured ACE2 and ACE expression in renal biopsies of patients with kidney disease due to type 2 diabetes to determine if the expression pattern is specific to diabetic nephropathy. ACE2 and ACE mRNA levels were measured by real-time PCR in laser microdissected renal biopsies from 13 diabetic and 8 control patients. ACE2 mRNA was significantly reduced by more than half in both the glomeruli and proximal tubules of the diabetic patients compared to controls, but ACE mRNA was increased in both compartments. There was a significant parallel decrease in ACE2 protein expression, determined by immunohistochemistry, in proximal tubules, a pattern not found in 12 patients with focal glomerulosclerosis or 10 patients with chronic allograft nephropathy. Our results suggest that the kidney disease of patients with type 2 diabetes is associated with a reduction in ACE2 gene and protein expression and this may contribute to the progression of renal injury.


Asunto(s)
Diabetes Mellitus Tipo 2/metabolismo , Enfermedades Renales/metabolismo , Glomérulos Renales/metabolismo , Túbulos Renales/metabolismo , Peptidil-Dipeptidasa A/genética , Adulto , Enzima Convertidora de Angiotensina 2 , Estudios de Casos y Controles , Diabetes Mellitus Tipo 2/enzimología , Femenino , Glomeruloesclerosis Focal y Segmentaria , Humanos , Enfermedades Renales/enzimología , Glomérulos Renales/enzimología , Túbulos Renales/enzimología , Masculino , Persona de Mediana Edad , Peptidil-Dipeptidasa A/análisis , ARN Mensajero/sangre
15.
Nat Clin Pract Nephrol ; 4(12): 693-7, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18838984

RESUMEN

BACKGROUND: A 12-year-old boy presented to hospital with a 6-month history of crampy pre-defecation abdominal pain, non-bloody diarrhea, anorexia and weight loss. Investigations revealed hypochromic microcytic anemia, a low serum iron level, a low serum ferritin level and an elevated serum creatinine level. Histopathological examination of tissue specimens obtained at esophagogastroduodenoscopy and colonoscopy revealed features of Crohn's disease, and a renal biopsy demonstrated tubulointerstitial nephritis. A second case of tubulointerstitial nephritis in a patient with Crohn's disease, is also presented. INVESTIGATIONS: Physical examination, laboratory tests including full blood count, electrolytes, renal function, serum albumin, urinalysis and 24 h urinary protein, esophagogastroduodenoscopy, colonoscopy, abdominal ultrasonography, dimercaptosuccinic acid scan, renal diethylene triamine pentaacetic acid clearance study and renal biopsy. DIAGNOSIS: Tubulointerstitial nephritis secondary to Crohn's disease. MANAGEMENT: Prednisone therapy (60 mg/day) for 1 month followed by a tapering schedule over 3 months.


Asunto(s)
Enfermedad de Crohn/complicaciones , Nefritis Intersticial/etiología , Niño , Humanos , Masculino
17.
Am J Kidney Dis ; 43(2): e25-30, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-14750122

RESUMEN

Glomerulonephritis secondary to endocarditis is uncommon and usually associated with valvular infection by blood culture-positive bacteria. We report 3 cases of necrotizing glomerulonephritis associated with culture-negative endocarditis caused by Bartonella henselae. Two of the patients presented with renal abnormalities and were investigated for endocarditis after results of renal biopsy. All 3 patients had an immune complex-mediated necrotizing and crescentic glomerulonephritis with mesangial and capillary wall deposition of immunoglobulin M (IgM), IgG, and C3. Electron microscopy showed immune-type electron-dense deposits in the mesangium and segmental subendothelial (2 cases) or subepithelial (1 case) deposits. Patients were treated with antibiotics, including azithromycin or doxycycline and ceftriaxone or tobramycin. In addition, 2 patients were administered steroids and 2 patients underwent valve replacement surgery. The 2 patients who underwent cardiac surgery were discharged from the hospital with stable renal function. The third patient died 4 months after hospital admission of renal failure. In conclusion, glomerulonephritis caused by B henselae endocarditis is an immune complex-mediated disease characterized by segmental necrotizing and crescentic glomerular lesions that can respond to aggressive medical and surgical therapy.


Asunto(s)
Infecciones por Bartonella/complicaciones , Bartonella henselae , Endocarditis Bacteriana/complicaciones , Glomerulonefritis/etiología , Adulto , Infecciones por Bartonella/diagnóstico , Bartonella henselae/inmunología , Biopsia , Femenino , Glomerulonefritis/inmunología , Glomerulonefritis/patología , Humanos , Masculino , Microscopía Electrónica , Microscopía Fluorescente , Persona de Mediana Edad , Necrosis
18.
PLoS One ; 9(8): e103413, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25133636

RESUMEN

IgA nephropathy (IgAN) is a clinically and pathologically heterogeneous disease. Endocapillary proliferation is associated with higher risk of progressive disease, and clinical studies suggest that corticosteroids mitigate this risk. However, corticosteroids are associated with protean cellular effects and significant toxicity. Furthermore the precise mechanism by which they modulate kidney injury in IgAN is not well delineated. To better understand molecular pathways involved in the development of endocapillary proliferation and to identify novel specific therapeutic targets, we evaluated the glomerular transcriptome of microdissected kidney biopsies from 22 patients with IgAN. Endocapillary proliferation was defined according to the Oxford scoring system independently by 3 nephropathologists. We analyzed mRNA expression using microarrays and identified transcripts differentially expressed in patients with endocapillary proliferation compared to IgAN without endocapillary lesions. Next, we employed both transcription factor analysis and in silico drug screening and confirmed that the endocapillary proliferation transcriptome is significantly enriched with pathways that can be impacted by corticosteroids. With this approach we also identified novel therapeutic targets and bioactive small molecules that may be considered for therapeutic trials for the treatment of IgAN, including resveratrol and hydroquinine. In summary, we have defined the distinct molecular profile of a pathologic phenotype associated with progressive renal insufficiency in IgAN. Exploration of the pathways associated with endocapillary proliferation confirms a molecular basis for the clinical effectiveness of corticosteroids in this subgroup of IgAN, and elucidates new therapeutic strategies for IgAN.


Asunto(s)
Glomerulonefritis por IGA/metabolismo , Transcriptoma , Corticoesteroides/uso terapéutico , Adulto , Simulación por Computador , Evaluación Preclínica de Medicamentos , Femenino , Glomerulonefritis por IGA/tratamiento farmacológico , Glomerulonefritis por IGA/patología , Humanos , Glomérulos Renales/irrigación sanguínea , Glomérulos Renales/patología , Masculino , Persona de Mediana Edad , Terapia Molecular Dirigida , Neovascularización Patológica/metabolismo , Fenotipo , Adulto Joven
19.
Clin J Am Soc Nephrol ; 8(8): 1449-59, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23393107

RESUMEN

Pathology consensus review for clinical trials and disease classification has historically been performed by manual light microscopy with sequential section review by study pathologists, or multi-headed microscope review. Limitations of this approach include high intra- and inter-reader variability, costs, and delays for slide mailing and consensus reviews. To improve this, the Nephrotic Syndrome Study Network (NEPTUNE) is systematically applying digital pathology review in a multicenter study using renal biopsy whole slide imaging (WSI) for observation-based data collection. Study pathology materials are acquired, scanned, uploaded, and stored in a web-based information system that is accessed through a web-browser interface. Quality control includes metadata and image quality review. Initially, digital slides are annotated, with each glomerulus identified, given a unique number, and maintained in all levels until the glomerulus disappears or sections end. The software allows viewing and annotation of multiple slide sections concurrently. Analysis utilizes "descriptors" for patterns of injury, rather than diagnoses, in renal parenchymal compartments. This multidimensional representation via WSI, allows more accurate glomerular counting and identification of all lesions in each glomerulus, with data available in a searchable database. The use of WSI brings about efficiency critical to pathology review in a clinical trial setting, including independent review by multiple pathologists, improved intraobserver and interobserver reproducibility, efficiencies and risk reduction in slide circulation and mailing, centralized management of data integrity and slide images for current or future studies, and web-based consensus meetings. The overall effect is improved incorporation of pathology review in a budget neutral approach.


Asunto(s)
Riñón/patología , Microscopía/métodos , Síndrome Nefrótico/patología , Biopsia , Humanos , Procesamiento de Señales Asistido por Computador
20.
Clin J Am Soc Nephrol ; 7(6): 914-25, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22461531

RESUMEN

BACKGROUND AND OBJECTIVES: Collapsing glomerulopathy is a podocytopathy with segmental or global wrinkling and collapse of capillary walls and overlying epithelial cell proliferation. Idiopathic collapsing glomerulopathy is a distinct clinicopathologic entity with significant proteinuria, poor response to immunosuppressive therapy, and rapid progression to renal failure. Collapsing glomerulopathy is associated with viral infections, autoimmune disease, and drugs. This work presents the largest group of collapsing glomerulopathy in patients with SLE. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Clinicopathological features were retrospectively studied in 19 patients with SLE (16 patients) or SLE-like (3 patients) disease with collapsing glomerulopathy. RESULTS: Initially, 95% of patients had nephrotic syndrome with proteinuria of 3-12 g per 24 hours, creatinine levels of 0.6-9.6 mg/dl, positive lupus serologies, and normal complement levels in 63%. Segmental and/or global collapsing glomerulopathy was seen in 11%-77% of glomeruli. Tubular atrophy with focal microcystic changes and interstitial fibrosis was seen in 35% of patients. Minimal glomerular mesangial deposits were noted in 63% of patients, and extensive foot process effacement was seen in 82% of patients. Initial treatment was with pulse/oral steroids. Follow-up from 13 patients revealed that 7 patients progressed to ESRD at the time of biopsy up to 21 months later, 1 patient returned to normal creatinine (1.1 mg/dl) without proteinuria, and 5 patients had creatinine of 1.2-3.6 mg/dl with proteinuria of 0.37-4 g per 24 hours. CONCLUSIONS: Collapsing glomerulopathy may be seen in SLE patients presenting with massive proteinuria with or without lupus nephritis, which may have prognostic significance.


Asunto(s)
Glomérulos Renales/patología , Lupus Eritematoso Sistémico/complicaciones , Nefritis Lúpica/etiología , Administración Oral , Adolescente , Adulto , Anciano , Atrofia , Biopsia , Progresión de la Enfermedad , Femenino , Fibrosis , Humanos , Inmunohistoquímica , Fallo Renal Crónico/etiología , Fallo Renal Crónico/patología , Glomérulos Renales/efectos de los fármacos , Túbulos Renales/patología , Lupus Eritematoso Sistémico/tratamiento farmacológico , Lupus Eritematoso Sistémico/patología , Nefritis Lúpica/tratamiento farmacológico , Nefritis Lúpica/patología , Masculino , Persona de Mediana Edad , Síndrome Nefrótico/etiología , Síndrome Nefrótico/patología , Proteinuria/etiología , Proteinuria/patología , Quimioterapia por Pulso , Estudios Retrospectivos , Esteroides/administración & dosificación , Factores de Tiempo , Resultado del Tratamiento , Adulto Joven
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