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1.
Am J Physiol Renal Physiol ; 326(5): F704-F726, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38482556

RESUMO

PAX2 regulates kidney development, and its expression persists in parietal epithelial cells (PECs), potentially serving as a podocyte reserve. We hypothesized that mice with a Pax2 pathogenic missense variant (Pax2A220G/+) have impaired PEC-mediated podocyte regeneration. Embryonic wild-type mouse kidneys showed overlapping expression of PAX2/Wilms' tumor-1 (WT-1) until PEC and podocyte differentiation, reflecting a close lineage relationship. Embryonic and adult Pax2A220G/+ mice have reduced nephron number but demonstrated no glomerular disease under baseline conditions. Pax2A220G/+ mice compared with wild-type mice were more susceptible to glomerular disease after adriamycin (ADR)-induced podocyte injury, as demonstrated by worsened glomerular scarring, increased podocyte foot process effacement, and podocyte loss. There was a decrease in PAX2-expressing PECs in wild-type mice after adriamycin injury accompanied by the occurrence of PAX2/WT-1-coexpressing glomerular tuft cells. In contrast, Pax2A220G/+ mice showed no changes in the numbers of PAX2-expressing PECs after adriamycin injury, associated with fewer PAX2/WT-1-coexpressing glomerular tuft cells compared with injured wild-type mice. A subset of PAX2-expressing glomerular tuft cells after adriamycin injury was increased in Pax2A220G/+ mice, suggesting a pathological process given the worse outcomes observed in this group. Finally, Pax2A220G/+ mice have increased numbers of glomerular tuft cells expressing Ki-67 and cleaved caspase-3 compared with wild-type mice after adriamycin injury, consistent with maladaptive responses to podocyte loss. Collectively, our results suggest that decreased glomerular numbers in Pax2A220G/+ mice are likely compounded with the inability of their mutated PECs to regenerate podocyte loss, and together these two mechanisms drive the worsened focal segmental glomerular sclerosis phenotype in these mice.NEW & NOTEWORTHY Congenital anomalies of the kidney and urinary tract comprise some of the leading causes of kidney failure in children, but our previous study showed that one of its genetic causes, PAX2, is also associated with adult-onset focal segmental glomerular sclerosis. Using a clinically relevant model, our present study demonstrated that after podocyte injury, parietal epithelial cells expressing PAX2 are deployed into the glomerular tuft to assist in repair in wild-type mice, but this mechanism is impaired in Pax2A220G/+ mice.


Assuntos
Doxorrubicina , Glomérulos Renais , Mutação de Sentido Incorreto , Fator de Transcrição PAX2 , Podócitos , Animais , Fator de Transcrição PAX2/genética , Fator de Transcrição PAX2/metabolismo , Podócitos/metabolismo , Podócitos/patologia , Glomérulos Renais/patologia , Glomérulos Renais/metabolismo , Doxorrubicina/toxicidade , Camundongos , Regeneração , Modelos Animais de Doenças , Proliferação de Células , Camundongos Endogâmicos C57BL , Fenótipo , Apoptose , Masculino , Nefropatias/genética , Nefropatias/patologia , Nefropatias/metabolismo , Nefropatias/induzido quimicamente
2.
Am J Kidney Dis ; 81(5): 591-605, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36509342

RESUMO

Thrombotic microangiopathy (TMA), a pathological lesion observed in a wide spectrum of diseases, is triggered by endothelial injury and/or dysfunction. Although TMA lesions are often accompanied by clinical features of microangiopathic hemolytic anemia, thrombocytopenia, and ischemic end-organ injury, renal-limited forms of TMA are not infrequently encountered in clinical practice. The presence of renal-limited manifestations can be diagnostically challenging, often delaying the initiation of targeted therapy. Prompt investigation and empirical treatment of TMA is warranted to reduce associated morbidity and mortality. Major advances have been made with respect to the pathophysiology of primary TMA entities, with the subsequent development of novel diagnostic tools and lifesaving therapies for diseases like thrombotic thrombocytopenic purpura and complement-mediated TMA. This article will review the clinical presentation and pathologic hallmarks of TMA involving the kidney, and the disease-specific mechanisms that contribute to the endothelial injury that characterizes TMA lesions. Diagnostic approach and both empirical and disease-specific treatment strategies will be discussed, along with the potential role for emerging targeted disease-specific therapies.


Assuntos
Anemia Hemolítica , Púrpura Trombocitopênica Trombótica , Microangiopatias Trombóticas , Humanos , Microangiopatias Trombóticas/diagnóstico , Microangiopatias Trombóticas/etiologia , Microangiopatias Trombóticas/terapia , Púrpura Trombocitopênica Trombótica/diagnóstico , Púrpura Trombocitopênica Trombótica/terapia , Anemia Hemolítica/terapia , Rim , Troca Plasmática
3.
Mol Cell Proteomics ; 20: 100101, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34033948

RESUMO

Normothermic ex-vivo kidney perfusion (NEVKP) results in significantly improved graft function in porcine auto-transplant models of donation after circulatory death injury compared with static cold storage (SCS); however, the molecular mechanisms underlying these beneficial effects remain unclear. We performed an unbiased proteomics analysis of 28 kidney biopsies obtained at three time points from pig kidneys subjected to 30 min of warm ischemia, followed by 8 h of NEVKP or SCS, and auto-transplantation. 70/6593 proteins quantified were differentially expressed between NEVKP and SCS groups (false discovery rate < 0.05). Proteins increased in NEVKP mediated key metabolic processes including fatty acid ß-oxidation, the tricarboxylic acid cycle, and oxidative phosphorylation. Comparison of our findings with external datasets of ischemia-reperfusion and other models of kidney injury confirmed that 47 of our proteins represent a common signature of kidney injury reversed or attenuated by NEVKP. We validated key metabolic proteins (electron transfer flavoprotein subunit beta and carnitine O-palmitoyltransferase 2, mitochondrial) by immunoblotting. Transcription factor databases identified members of the peroxisome proliferator-activated receptors (PPAR) family of transcription factors as the upstream regulators of our dataset, and we confirmed increased expression of PPARA, PPARD, and RXRA in NEVKP with reverse transcription polymerase chain reaction. The proteome-level changes observed in NEVKP mediate critical metabolic pathways. These effects may be coordinated by PPAR-family transcription factors and may represent novel therapeutic targets in ischemia-reperfusion injury.


Assuntos
Rim/metabolismo , Proteínas Mitocondriais/metabolismo , Animais , Transplante de Rim , Masculino , Perfusão , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Proteômica , Suínos
4.
BMC Nephrol ; 22(1): 320, 2021 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-34565340

RESUMO

BACKGROUND: Focal and segmental glomerulosclerosis (FSGS) is a histologic pattern of injury that characterizes a wide spectrum of diseases. Many genetic causes have been identified in FSGS but even in families with comprehensive testing, a significant proportion remain unexplained. METHODS: In a family with adult-onset autosomal dominant FSGS, linkage analysis was performed in 11 family members followed by whole exome sequencing (WES) in 3 affected relatives to identify candidate genes. RESULTS: Pathogenic variants in known nephropathy genes were excluded. Subsequently, linkage analysis was performed and narrowed the disease gene(s) to within 3% of the genome. WES identified 5 heterozygous rare variants, which were sequenced in 11 relatives where DNA was available. Two of these variants, in LAMA2 and LOXL4, remained as candidates after segregation analysis and encode extracellular matrix proteins of the glomerulus. Renal biopsies showed classic segmental sclerosis/hyalinosis lesion on a background of mild mesangial hypercellularity. Examination of basement membranes with electron microscopy showed regions of dense mesangial matrix in one individual and wider glomerular basement membrane (GBM) thickness in two individuals compared to historic control averages. CONCLUSIONS: Based on our findings, we postulate that the additive effect of digenic inheritance of heterozygous variants in LAMA2 and LOXL4 leads to adult-onset FSGS. Limitations to our study includes the absence of functional characterization to support pathogenicity. Alternatively, identification of additional FSGS cases with suspected deleterious variants in LAMA2 and LOXL4 will provide more evidence for disease causality. Thus, our report will be of benefit to the renal community as sequencing in renal disease becomes more widespread.


Assuntos
Glomerulosclerose Segmentar e Focal/genética , Laminina/genética , Proteína-Lisina 6-Oxidase/genética , Idade de Início , Idoso , Membrana Basal/ultraestrutura , Transtornos Cromossômicos/genética , Feminino , Testes Genéticos , Heterozigoto , Humanos , Rim/ultraestrutura , Masculino , Pessoa de Meia-Idade , Mutação , Linhagem , Sequenciamento do Exoma
5.
J Am Soc Nephrol ; 31(11): 2705-2724, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32900843

RESUMO

BACKGROUND: Antibody-mediated rejection (AMR) accounts for >50% of kidney allograft loss. Donor-specific antibodies (DSA) against HLA and non-HLA antigens in the glomeruli and the tubulointerstitium cause AMR while inflammatory cytokines such as TNFα trigger graft injury. The mechanisms governing cell-specific injury in AMR remain unclear. METHODS: Unbiased proteomic analysis of laser-captured and microdissected glomeruli and tubulointerstitium was performed on 30 for-cause kidney biopsy specimens with early AMR, acute cellular rejection (ACR), or acute tubular necrosis (ATN). RESULTS: A total of 107 of 2026 glomerular and 112 of 2399 tubulointerstitial proteins was significantly differentially expressed in AMR versus ACR; 112 of 2026 glomerular and 181 of 2399 tubulointerstitial proteins were significantly dysregulated in AMR versus ATN (P<0.05). Basement membrane and extracellular matrix (ECM) proteins were significantly decreased in both AMR compartments. Glomerular and tubulointerstitial laminin subunit γ-1 (LAMC1) expression decreased in AMR, as did glomerular nephrin (NPHS1) and receptor-type tyrosine-phosphatase O (PTPRO). The proteomic analysis revealed upregulated galectin-1, which is an immunomodulatory protein linked to the ECM, in AMR glomeruli. Anti-HLA class I antibodies significantly increased cathepsin-V (CTSV) expression and galectin-1 expression and secretion in human glomerular endothelial cells. CTSV had been predicted to cleave ECM proteins in the AMR glomeruli. Glutathione S-transferase ω-1, an ECM-modifying enzyme, was significantly increased in the AMR tubulointerstitium and in TNFα-treated proximal tubular epithelial cells. CONCLUSIONS: Basement membranes are often remodeled in chronic AMR. Proteomic analysis performed on laser-captured and microdissected glomeruli and tubulointerstitium identified early ECM remodeling, which may represent a new therapeutic opportunity.


Assuntos
Membrana Basal/metabolismo , Matriz Extracelular/metabolismo , Rejeição de Enxerto/metabolismo , Rejeição de Enxerto/patologia , Glomérulos Renais/patologia , Túbulos Renais/patologia , Adulto , Idoso , Aloenxertos/metabolismo , Aloenxertos/patologia , Anticorpos/metabolismo , Biópsia , Catepsinas/metabolismo , Linhagem Celular , Cisteína Endopeptidases/metabolismo , Matriz Extracelular/patologia , Feminino , Galectina 1/genética , Galectina 1/metabolismo , Expressão Gênica , Glutationa Transferase/metabolismo , Rejeição de Enxerto/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Glomérulos Renais/metabolismo , Transplante de Rim , Túbulos Renais/metabolismo , Laminina/metabolismo , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 3 da Matriz/metabolismo , Proteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Necrose , Proteômica , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Fator de Necrose Tumoral alfa/farmacologia
6.
Int J Mol Sci ; 22(17)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34502419

RESUMO

Our understanding of the mechanisms responsible for the progression of chronic kidney disease (CKD) is incomplete. Microarray analysis of kidneys at 4 and 7 weeks of age in Col4a3-/- mice, a model of progressive nephropathy characterized by proteinuria, interstitial fibrosis, and inflammation, revealed that Follistatin-like-1 (Fstl1) was one of only four genes significantly overexpressed at 4 weeks of age. mRNA levels for the Fstl1 receptors, Tlr4 and Dip2a, increased in both Col4a-/- mice and mice subjected to unilateral ureteral obstruction (UUO). RNAscope® (Advanced Cell Diagnostics, Newark CA, USA) localized Fstl1 to interstitial cells, and in silico analysis of single cell transcriptomic data from human kidneys showed Fstl1 confined to interstitial fibroblasts/myofibroblasts. In vitro, FSTL1 activated AP1 and NFκB, increased collagen I (COL1A1) and interleukin-6 (IL6) expression, and induced apoptosis in cultured kidney cells. FSTL1 expression in the NEPTUNE cohort of humans with focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), and IgA nephropathy (IgAN) was positively associated with age, eGFR, and proteinuria by multiple linear regression, as well as with interstitial fibrosis and tubular atrophy. Clinical disease progression, defined as dialysis or a 40 percent reduction in eGFR, was greater in patients with high baseline FSTL1 mRNA levels. FSTL1 is a fibroblast-derived cytokine linked to the progression of experimental and clinical CKD.


Assuntos
Fatores de Crescimento de Fibroblastos/metabolismo , Proteínas Relacionadas à Folistatina/metabolismo , Insuficiência Renal Crônica/metabolismo , Animais , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Cadeia alfa 1 do Colágeno Tipo I , Modelos Animais de Doenças , Progressão da Doença , Fatores de Crescimento de Fibroblastos/genética , Proteínas Relacionadas à Folistatina/genética , Camundongos , Camundongos Knockout , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/patologia , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo
7.
Kidney Int ; 98(1): 116-132, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32418621

RESUMO

Tubulointerstitial injury is an important determinant of chronic kidney disease progression, yet treatment is limited. Accordingly, we derived a chronic kidney disease progression signature based on aging and disease in Col4a3-/- mice, a model associated with proteinuria and progressive loss of kidney function. Computational drug repurposing with the Connectivity Map identified vorinostat, a lysine deacetylase inhibitor, as a candidate treatment to reverse progression signature gene expression. Vorinostat administration significantly increased the lifespan of Col4a3-/- mice and attenuated tubulointerstitial fibrosis and JNK phosphorylation in the kidneys of Col4a3-/- mice. In vitro, vorinostat reduced albumin- and angiotensin II-induced activation of canonical mitogen-activated protein kinases in kidney tubular epithelial cells. Finally, a subset of murine progression signature genes was differentially expressed across kidney transcriptomic data from patients with focal segmental glomerulosclerosis, IgA nephropathy, and diabetic nephropathy. Thus, our findings suggest that lysine deacetylase inhibition may be a novel treatment to chronic kidney disease associated with proteinuria and progressive tubulointerstitial injury.


Assuntos
Glomerulosclerose Segmentar e Focal , Insuficiência Renal Crônica , Animais , Progressão da Doença , Fibrose , Glomerulosclerose Segmentar e Focal/patologia , Humanos , Rim/patologia , Lisina , Camundongos , Insuficiência Renal Crônica/tratamento farmacológico , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/patologia
8.
Int J Mol Sci ; 21(24)2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33348732

RESUMO

Renal ischemia reperfusion injury (IRI) is associated with inflammation, including neutrophil infiltration that exacerbates the initial ischemic insult. The molecular pathways involved are poorly characterized and there is currently no treatment. We performed an in silico analysis demonstrating changes in NFκB-mediated gene expression in early renal IRI. We then evaluated NFκB-blockade with a BRD4 inhibitor on neutrophil adhesion to endothelial cells in vitro, and tested BRD4 inhibition in an in vivo IRI model. BRD4 inhibition attenuated neutrophil adhesion to activated endothelial cells. In vivo, IRI led to increased expression of cytokines and adhesion molecules at 6 h post-IRI with sustained up-regulated expression to 48 h post-IRI. These effects were attenuated, in part, with BRD4 inhibition. Absolute neutrophil counts increased significantly in the bone marrow, blood, and kidney 24 h post-IRI. Activated neutrophils increased in the blood and kidney at 6 h post-IRI and remained elevated in the kidney until 48 h post-IRI. BRD4 inhibition reduced both total and activated neutrophil counts in the kidney. IRI-induced tubular injury correlated with neutrophil accumulation and was reduced by BRD4 inhibition. In summary, BRD4 inhibition has important systemic and renal effects on neutrophils, and these effects are associated with reduced renal injury.


Assuntos
Adesão Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/antagonistas & inibidores , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Ativação de Neutrófilo/efeitos dos fármacos , Neutrófilos/imunologia , Proteínas Nucleares/antagonistas & inibidores , Traumatismo por Reperfusão/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Animais , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Transformada , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Rim/citologia , Rim/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Neutrófilos/efeitos dos fármacos , Proteínas Nucleares/metabolismo , Traumatismo por Reperfusão/imunologia , Transdução de Sinais/efeitos dos fármacos , Fatores de Transcrição/metabolismo
9.
Am J Transplant ; 18(3): 580-589, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28889600

RESUMO

Normothermic ex vivo kidney perfusion (NEVKP) represents a novel approach for graft preservation and functional improvement in kidney transplantation. We investigated whether NEVKP also allows graft quality assessment before transplantation. Kidneys from 30-kg pigs were recovered in a model of heart-beating donation (group A) after 30 minutes (group B) or 60 minutes (group C) (n = 5/group) of warm ischemia. After 8 hours of NEVKP, contralateral kidneys were resected, grafts were autotransplanted, and the pigs were followed for 3 days. After transplantation, renal function measured based on peak serum creatinine differed significantly among groups (P < .05). Throughout NEVKP, intrarenal resistance was lowest in group A and highest in group C (P < .05). intrarenal resistance at the initiation of NEVKP correlated with postoperative renal function (P < .001 at NEVKP hour 1). Markers of acid-base homeostasis (pH, HCO3- , base excess) differed among groups (P < .05) and correlated with posttransplantation renal function (P < .001 for pH at NEVKP hour 1). Similarly, lactate and aspartate aminotransferase were lowest in noninjured grafts versus donation after circulatory death kidneys (P < .05) and correlated with posttransplantation kidney function (P < .001 for lactate at NEVKP hour 1). In conclusion, assessment of perfusion characteristics and clinically available perfusate biomarkers during NEVKP allows the prediction of posttransplantation graft function. Thus, NEVKP might allow decision-making regarding whether grafts are suitable for transplantation.


Assuntos
Transplante de Rim/métodos , Preservação de Órgãos/métodos , Garantia da Qualidade dos Cuidados de Saúde/normas , Medição de Risco/métodos , Doadores de Tecidos/provisão & distribuição , Coleta de Tecidos e Órgãos/normas , Obtenção de Tecidos e Órgãos/normas , Animais , Masculino , Modelos Animais , Perfusão , Suínos , Temperatura , Coleta de Tecidos e Órgãos/métodos
10.
Am J Kidney Dis ; 71(3): 441-445, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29198386

RESUMO

Alport syndrome is a rare hereditary disorder caused by rare variants in 1 of 3 genes encoding for type IV collagen. Rare variants in COL4A5 on chromosome Xq22 cause X-linked Alport syndrome, which accounts for ∼80% of the cases. Alport syndrome has a variable clinical presentation, including progressive kidney failure, hearing loss, and ocular defects. Exome sequencing performed in 2 affected related males with an undefined X-linked glomerulopathy characterized by global and segmental glomerulosclerosis, mesangial hypercellularity, and vague basement membrane immune complex deposition revealed a COL4A5 sequence variant, a substitution of a thymine by a guanine at nucleotide 665 (c.T665G; rs281874761) of the coding DNA predicted to lead to a cysteine to phenylalanine substitution at amino acid 222, which was not seen in databases cataloguing natural human genetic variation, including dbSNP138, 1000 Genomes Project release version 01-11-2004, Exome Sequencing Project 21-06-2014, or ExAC 01-11-2014. Review of the literature identified 2 additional families with the same COL4A5 variant leading to similar atypical histopathologic features, suggesting a unique pathologic mechanism initiated by this specific rare variant. Homology modeling suggests that the substitution alters the structural and dynamic properties of the type IV collagen trimer. Genetic analysis comparing members of the 3 families indicated a distant relationship with a shared haplotype, implying a founder effect.


Assuntos
Colágeno Tipo IV/genética , Predisposição Genética para Doença , Nefrite Hereditária/genética , Nefrite Hereditária/patologia , Linhagem , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Biópsia por Agulha , Análise Mutacional de DNA , Seguimentos , Efeito Fundador , Testes Genéticos/métodos , Variação Genética , Humanos , Imuno-Histoquímica , Masculino , Nefrite Hereditária/diagnóstico , Nefrite Hereditária/tratamento farmacológico , Medição de Risco , Índice de Gravidade de Doença , Esteroides/uso terapêutico , Adulto Jovem
11.
Pediatr Nephrol ; 33(6): 991-993, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-28785983

RESUMO

BACKGROUND: Sarcoidosis is a multisystem granulomatous disease of unknown etiology that rarely presents in childhood. Here, we report a case of pediatric sarcoidosis presenting with renal failure and hypercalcemia. CASE DIAGNOSIS/TREATMENT: A previously well 14-year-old Caucasian boy was admitted to the Hospital for Sick Children, Canada, for hypertension and renal failure following work-up by his family physician for initial concerns of growth failure. On admission, his weight was 35 kg (<3rd percentile), his height was 148 cm (≪3rd percentile), and his blood pressure was 154/116 mmHg (>99th percentile for height). Laboratory findings showed elevated creatinine (218 µmol/L), hypercalcemia (3.21 mmol/L), and normocytic anemia (hemoglobin 105 g/L). His further assessment showed a urinary concentrating defect with hypercalciuria (calcium/creatinine 1.76 mmol/mmol) and nephrocalcinosis on ultrasound. His eye examination showed uveitis with conjunctival biopsy remarkable for granulomas, which led to pursuit of a diagnosis of possible sarcoidosis. Angiotensin-converting enzyme was found to be high at 96 U/L, and he had a renal biopsy that was consistent with interstitial nephritis with granulomas. Treatment was started with prednisone leading to resolution of his hypercalcemia but persistence of his mild chronic kidney disease. CONCLUSIONS: This case represents an atypical presentation of a rare pediatric disease and highlights the spectrum of renal manifestations and treatment options in sarcoidosis.


Assuntos
Insuficiência de Crescimento/etiologia , Hipercalcemia/etiologia , Insuficiência Renal/etiologia , Sarcoidose/diagnóstico , Adolescente , Diagnóstico Diferencial , Glucocorticoides/uso terapêutico , Humanos , Rim/patologia , Masculino , Prednisona/uso terapêutico , Sarcoidose/complicações , Sarcoidose/tratamento farmacológico
12.
Pediatr Nephrol ; 33(6): 995-999, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-28785985

RESUMO

BACKGROUND: Sarcoidosis is a multisystem granulomatous disease of unknown etiology that rarely presents in childhood. Here, we report a case of pediatric sarcoidosis, presenting with renal failure and hypercalcemia. CASE DIAGNOSIS/TREATMENT: A previously well 14-year-old Caucasian boy was admitted to the Hospital for Sick Children, Canada, for hypertension and renal failure following work-up by his family physician for initial concerns of growth failure. On admission, his weight was 35 kg (<3rd percentile), his height was 148 cm (<<3rd percentile), and his blood pressure was 154/116 mmHg (>99th percentile for height). Laboratory findings showed elevated creatinine (218 umol/L), hypercalcemia (3.21 mmol/L), and normocytic anemia (hemoglobin 105 g/L). His further assessment showed a urinary concentrating defect with hypercalciuria (calcium/creatinine 1.76 mmol/mmol) and nephrocalcinosis on ultrasound. His eye examination showed uveitis with conjunctival biopsy remarkable for granulomas, which led to pursuit of a diagnosis of possible sarcoidosis. Angiotensin Angiotensin-converting enzyme was found to be high at 96 U/L, and he had a renal biopsy that was consistent with interstitial nephritis with granulomas. Treatment was started with prednisone leading to resolution of his hypercalcemia but persistence of his mild chronic kidney disease. CONCLUSIONS: This case represents an atypical presentation of a rare pediatric disease and highlights the spectrum of renal manifestations and treatment options in sarcoidosis.


Assuntos
Insuficiência de Crescimento/etiologia , Hipercalcemia/etiologia , Insuficiência Renal/etiologia , Sarcoidose/diagnóstico , Adolescente , Diagnóstico Diferencial , Humanos , Rim/patologia , Masculino , Sarcoidose/complicações , Sarcoidose/tratamento farmacológico
14.
Kidney Int ; 91(6): 1347-1361, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28249676

RESUMO

Angiotensin-converting enzyme 2 (ACE2) is a monocarboxypeptidase in the renin-angiotensin system that catalyzes the breakdown of angiotensin II to angiotensin 1-7. We have reported that ACE2 expression in the kidney is reduced in experimental Alport syndrome but the impact of this finding on disease progression has not been studied. Accordingly, we evaluated effects of murine recombinant ACE2 treatment in Col4a3 knockout mice, a model of Alport syndrome characterized by proteinuria and progressive renal injury. Murine recombinant ACE2 (0.5 mg/kg/day) was administered from four to seven weeks of age via osmotic mini-pump. Pathological changes were attenuated by murine recombinant ACE2 treatment which ameliorated kidney fibrosis as shown by decreased expression of COL1α1 mRNA, less accumulation of extracellular matrix proteins, and inhibition of transforming growth factor-ß signaling. Further, increases in proinflammatory cytokine expression, macrophage infiltration, inflammatory signaling pathway activation, and heme oxygenase-1 levels in Col4a3 knockout mice were also reduced by murine recombinant ACE2 treatment. Lastly, murine recombinant ACE2 influenced the turnover of renal ACE2, as it suppressed the expression of tumor necrosis factor-α converting enzyme, a negative regulator of ACE2. Thus, treatment with exogenous ACE2 alters angiotensin peptide metabolism in the kidneys of Col4a3 knockout mice and attenuates the progression of Alport syndrome nephropathy.


Assuntos
Rim/efeitos dos fármacos , Nefrite Hereditária/tratamento farmacológico , Peptidil Dipeptidase A/administração & dosagem , Albuminúria/tratamento farmacológico , Albuminúria/etiologia , Albuminúria/metabolismo , Enzima de Conversão de Angiotensina 2 , Angiotensinas/metabolismo , Animais , Autoantígenos/genética , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Cadeia alfa 1 do Colágeno Tipo I , Colágeno Tipo IV/deficiência , Colágeno Tipo IV/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Fibrose , Predisposição Genética para Doença , Mediadores da Inflamação/metabolismo , Rim/metabolismo , Rim/patologia , Masculino , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nefrite Hereditária/complicações , Nefrite Hereditária/genética , Nefrite Hereditária/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fenótipo , Proteínas Recombinantes/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Fator de Crescimento Transformador beta1/metabolismo
15.
Am J Kidney Dis ; 69(3): 473-476, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27856086

RESUMO

Preapproval clinical trials examining the safety and efficacy of rosuvastatin demonstrated an increased incidence of proteinuria, hematuria, rhabdomyolysis, and other acute kidney injury of unknown cause at high doses. The latter cases manifested with urine sediment findings and in some cases, renal histology, indicating renal tubular injury in the absence of rhabdomyolysis. Despite these provocative findings, there have been very few reports in the literature regarding non-rhabdomyolysis-mediated acute kidney injury associated with high-dose rosuvastatin since its widespread introduction more than a decade ago, suggesting that it is either a rare entity or systematically underdiagnosed and under-reported. We present a case of renal tubular toxicity attributable to the initiation of rosuvastatin treatment at a dose of 40mg in a patient with no prior evidence of kidney disease. Tubular toxicity should be considered in cases of unexplained kidney injury in the setting of exposure to a potent statin such as rosuvastatin, particularly at high dose. The limited evidence suggests a good kidney prognosis following withdrawal of the agent in these cases.


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Necrose Tubular Aguda/induzido quimicamente , Rosuvastatina Cálcica/efeitos adversos , Feminino , Humanos , Pessoa de Meia-Idade
16.
J Am Soc Nephrol ; 27(9): 2609-15, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26869008

RESUMO

Fibrosis and inflammation are closely intertwined injury pathways present in nearly all forms of CKD for which few safe and effective therapies exist. Slit glycoproteins signaling through Roundabout (Robo) receptors have been described to have anti-inflammatory effects through regulation of leukocyte cytoskeletal organization. Notably, cytoskeletal reorganization is also required for fibroblast responses to TGF-ß Here, we examined whether Slit2 also controls TGF-ß-induced renal fibrosis. In cultured renal fibroblasts, which we found to express Slit2 and Robo-1, the bioactive N-terminal fragment of Slit2 inhibited TGF-ß-induced collagen synthesis, actin cytoskeletal reorganization, and Smad2/3 transcriptional activity, but the inactive C-terminal fragment of Slit2 did not. In mouse models of postischemic renal fibrosis and obstructive uropathy, treatment with N-terminal Slit2 before or after injury inhibited the development of renal fibrosis and preserved renal function, whereas the C-terminal Slit2 had no effect. Our data suggest that administration of recombinant Slit2 may be a new treatment strategy to arrest chronic injury progression after ischemic and obstructive renal insults by not only attenuating inflammation but also, directly inhibiting renal fibrosis.


Assuntos
Fibroblastos/efeitos dos fármacos , Fibroblastos/fisiologia , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Peptídeos e Proteínas de Sinalização Intercelular/uso terapêutico , Nefropatias/prevenção & controle , Rim/patologia , Proteínas do Tecido Nervoso/farmacologia , Proteínas do Tecido Nervoso/uso terapêutico , Fator de Crescimento Transformador beta/antagonistas & inibidores , Fator de Crescimento Transformador beta/fisiologia , Animais , Fibrose/prevenção & controle , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Recombinantes
17.
J Am Soc Nephrol ; 27(10): 3117-3128, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-26961347

RESUMO

Like many organs, the kidney stiffens after injury, a process that is increasingly recognized as an important driver of fibrogenesis. Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are related mechanosensory proteins that bind to Smad transcription factors, the canonical mediators of profibrotic TGF-ß responses. Here, we investigated the role of YAP/TAZ in the matrix stiffness dependence of fibroblast responses to TGF-ß In contrast to growth on a stiff surface, fibroblast growth on a soft matrix led to YAP/TAZ sequestration in the cytosol and impaired TGF-ß-induced Smad2/3 nuclear accumulation and transcriptional activity. YAP knockdown or treatment with verteporfin, a drug that was recently identified as a potent YAP inhibitor, elicited similar changes. Furthermore, verteporfin reduced YAP/TAZ levels and decreased the total cellular levels of Smad2/3 after TGF-ß stimulation. Verteporfin treatment of mice subjected to unilateral ureteral obstruction similarly reduced YAP/TAZ levels and nuclear Smad accumulation in the kidney, and attenuated renal fibrosis. Our data suggest that organ stiffening cooperates with TGF-ß to induce fibrosis in a YAP/TAZ- and Smad2/3-dependent manner. Interference with this YAP/TAZ and TGF-ß/Smad crosstalk likely underlies the antifibrotic activity of verteporfin. Finally, through repurposing of a clinically used drug, we illustrate the therapeutic potential of a novel mechanointerference strategy that blocks TGF-ß signaling and renal fibrogenesis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Rim/patologia , Fosfoproteínas/fisiologia , Proteína Smad2/fisiologia , Proteína Smad3/fisiologia , Fatores de Transcrição/fisiologia , Fator de Crescimento Transformador beta/fisiologia , Aciltransferases , Animais , Proteínas de Ciclo Celular , Fibrose/etiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais , Proteínas de Sinalização YAP
18.
J Mol Cell Cardiol ; 91: 11-22, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26718721

RESUMO

Ischemia/reperfusion, which is characterized by deficient oxygen supply and subsequent restoration of blood flow, can cause irreversible damages to tissue. Mechanisms contributing to the pathogenesis of ischemia reperfusion injury are complex, multifactorial and highly integrated. Extensive research has focused on increasing organ tolerance to ischemia reperfusion injury, especially through the use of ischemic conditioning strategies. Of morbidities that potentially compromise the protective mechanisms of the heart, diabetes mellitus appears primarily important to study. Diabetes mellitus increases myocardial susceptibility to ischemia reperfusion injury and also modifies myocardial responses to ischemic conditioning strategies by disruption of intracellular signaling responsible for enhancement of resistance to cell death. The purpose of this review is twofold: first, to summarize mechanisms underlying ischemia reperfusion injury and the signal transduction pathways underlying ischemic conditioning cardioprotection; and second, to focus on diabetes mellitus and mechanisms that may be responsible for the lack of effect of ischemic conditioning strategies in diabetes.


Assuntos
Diabetes Mellitus/terapia , Precondicionamento Isquêmico Miocárdico , Infarto do Miocárdio/terapia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Animais , Apoptose , Cálcio/metabolismo , Complicações do Diabetes , Diabetes Mellitus/metabolismo , Diabetes Mellitus/patologia , Estresse do Retículo Endoplasmático , Humanos , Infarto do Miocárdio/complicações , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Traumatismo por Reperfusão Miocárdica/complicações , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Estresse Oxidativo , Transdução de Sinais
19.
Am J Pathol ; 185(5): 1423-35, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25777062

RESUMO

Blockade of the renin-angiotensin system attenuates the progression of experimental and clinical Alport syndrome (AS); however, the underlying mechanism(s) remains largely unknown. We evaluated the renin-angiotensin system in 4- and 7-week-old homozygous for collagen, type IV, α3 gene (Col4A3(-/-)) and wild-type mice, a model of AS characterized by proteinuria and progressive renal injury. Renal angiotensin (Ang) II levels increased, whereas renal Ang-(1-7) levels decreased in 7-week-old Col4a3(-/-) mice compared with age-matched controls; these changes were partially reversed by recombinant angiotensin-converting enzyme 2 (ACE2) treatment. The expression of both the angiotensinogen and renin protein increased in Col4a3(-/-) compared with wild-type mice. Consistent with the Ang-(1-7) levels, the expression and activity of kidney ACE2 decreased in 7-week-old Col4a3(-/-) mice. The urinary excretion rate of ACE2 paralleled the decline in tissue expression. Expression of an Ang II-induced gene, heme oxygenase-1, was up-regulated in the kidneys of 7-week-old Col4a3(-/-) mice compared with wild-type mice by microarray analysis. Heme oxygenase-1 (HO-1) protein expression was increased in kidneys of Col4a3(-/-) mice and normalized by treatment with ACE inhibitor. Urinary HO-1 excretion paralleled renal HO-1 expression. In conclusion, progressive kidney injury in AS is associated with changes in expression of intrarenal renin Ang system components and Ang peptides. HO-1 and ACE2 may represent novel markers of AS-associated kidney injury, whereas administration of recombinant ACE2 and/or Ang-(1-7) may represent novel therapeutic approaches in AS.


Assuntos
Heme Oxigenase-1/metabolismo , Rim/metabolismo , Proteínas de Membrana/metabolismo , Nefrite Hereditária/metabolismo , Peptidil Dipeptidase A/metabolismo , Sistema Renina-Angiotensina/fisiologia , Enzima de Conversão de Angiotensina 2 , Animais , Western Blotting , Linhagem Celular , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Humanos , Imuno-Histoquímica , Rim/patologia , Camundongos , Camundongos Knockout , Nefrite Hereditária/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase em Tempo Real
20.
J Am Soc Nephrol ; 26(12): 2963-77, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25855771

RESUMO

Expression of thioredoxin-interacting protein (TxNIP), an endogenous inhibitor of the thiol oxidoreductase thioredoxin, is augmented by high glucose (HG) and promotes oxidative stress. We previously reported that TxNIP-deficient mesangial cells showed protection from HG-induced reactive oxygen species, mitogen-activated protein kinase phosphorylation, and collagen expression. Here, we investigated the potential role of TxNIP in the pathogenesis of diabetic nephropathy (DN) in vivo. Wild-type (WT) control, TxNIP(-/-), and TxNIP(+/-) mice were rendered equally diabetic with low-dose streptozotocin. In contrast to effects in WT mice, diabetes did not increase albuminuria, proteinuria, serum cystatin C, or serum creatinine levels in TxNIP(-/-) mice. Whereas morphometric studies of kidneys revealed a thickened glomerular basement membrane and effaced podocytes in the diabetic WT mice, these changes were absent in the diabetic TxNIP(-/-) mice. Immunohistochemical analysis revealed significant increases in the levels of glomerular TGF-ß1, collagen IV, and fibrosis only in WT diabetic mice. Additionally, only WT diabetic mice showed significant increases in oxidative stress (nitrotyrosine, urinary 8-hydroxy-2-deoxy-guanosine) and inflammation (IL-1ß mRNA, F4/80 immunohistochemistry). Expression levels of Nox4-encoded mRNA and protein increased only in the diabetic WT animals. A significant loss of podocytes, assessed by Wilms' tumor 1 and nephrin staining and urinary nephrin concentration, was found in diabetic WT but not TxNIP(-/-) mice. Furthermore, in cultured human podocytes exposed to HG, TxNIP knockdown with siRNA abolished the increased mitochondrial O2 (-) generation and apoptosis. These data indicate that TxNIP has a critical role in the progression of DN and may be a promising therapeutic target.


Assuntos
Proteínas de Transporte/metabolismo , Diabetes Mellitus Experimental/metabolismo , Nefropatias Diabéticas/metabolismo , Tiorredoxinas/metabolismo , Albuminúria/etiologia , Animais , Antígenos de Diferenciação/análise , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas de Transporte/genética , Células Cultivadas , Colágeno Tipo IV/análise , Creatinina/sangue , Cistatina C/sangue , Diabetes Mellitus Experimental/induzido quimicamente , Fibrose , Membrana Basal Glomerular/patologia , Glucose/farmacologia , Interleucina-1beta/genética , Glomérulos Renais/química , Glomérulos Renais/patologia , Proteínas de Membrana/análise , Camundongos , Camundongos Knockout , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Mitocôndrias/metabolismo , NADPH Oxidase 4 , NADPH Oxidases/genética , NADPH Oxidases/metabolismo , Estresse Oxidativo , Oxigênio/metabolismo , Podócitos/química , Podócitos/efeitos dos fármacos , Podócitos/patologia , RNA Mensageiro/análise , Proteínas Repressoras/análise , Estreptozocina , Tiorredoxinas/genética , Fator de Crescimento Transformador beta1/análise , Proteínas WT1
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