RESUMO
The mechanisms responsible for glomerular hemodynamic regulation with sodium-glucose co-transporter 2 (SGLT2) inhibitors in kidney disease due to type 2 diabetes remain unclear. Therefore, we investigated changes in glomerular hemodynamic function using an animal model of type 2 diabetes, treated with an SGLT2 inhibitor alone or in combination with a renin-angiotensin-aldosterone system inhibitor using male Zucker lean (ZL) and Zucker diabetic fatty (ZDF) rats. Afferent and efferent arteriolar diameter and single-nephron glomerular filtration rate (SNGFR) were evaluated in ZDF rats measured at 0, 30, 60, 90, and 120 minutes after the administration of a SGLT2 inhibitor (luseogliflozin). Additionally, we assessed these changes under the administration of the adenosine A1 receptor (A1aR) antagonist (8-cyclopentyl-1,3-dipropylxanthine), along with coadministration of luseogliflozin and an angiotensin II receptor blocker (ARB), telmisartan. ZDF rats had significantly increased SNGFR, and afferent and efferent arteriolar diameters compared to ZL rats, indicating glomerular hyperfiltration. Administration of luseogliflozin significantly reduced afferent vasodilatation and glomerular hyperfiltration, with no impact on efferent arteriolar diameter. Urinary adenosine levels were increased significantly in the SGLT2 inhibitor group compared to the vehicle group. A1aR antagonism blocked the effect of luseogliflozin on kidney function. Co-administration of the SGLT2 inhibitor and ARB decreased the abnormal expansion of glomerular afferent arterioles, whereas the efferent arteriolar diameter was not affected. Thus, regulation of afferent arteriolar vascular tone via the A1aR pathway is associated with glomerular hyperfiltration in type 2 diabetic kidney disease.
Assuntos
Diabetes Mellitus Tipo 2 , Nefropatias Diabéticas , Taxa de Filtração Glomerular , Glomérulos Renais , Ratos Zucker , Inibidores do Transportador 2 de Sódio-Glicose , Animais , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Masculino , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/fisiopatologia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Glomérulos Renais/efeitos dos fármacos , Glomérulos Renais/fisiopatologia , Glomérulos Renais/patologia , Glomérulos Renais/irrigação sanguínea , Taxa de Filtração Glomerular/efeitos dos fármacos , Ratos , Nefropatias Diabéticas/etiologia , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/fisiopatologia , Hemodinâmica/efeitos dos fármacos , Xantinas/farmacologia , Arteríolas/efeitos dos fármacos , Arteríolas/fisiopatologia , Antagonistas do Receptor A1 de Adenosina/farmacologia , Sistema Renina-Angiotensina/efeitos dos fármacos , Transportador 2 de Glucose-Sódio/metabolismo , Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Sorbitol/análogos & derivadosRESUMO
During peritoneal dialysis (PD), the peritoneum is exposed to a bioincompatible dialysate, deteriorating the tissue and limiting the long-term effectiveness of PD. Peritoneal fibrosis is triggered by chronic inflammation induced by a variety of stimuli, including peritonitis. Exposure to PD fluid alters peritoneal macrophages phenotype. Inflammasome activation triggers chronic inflammation. First, it was determined whether inflammasome activation causes peritoneal deterioration. In the in vivo experiments, the increased expression of the inflammasome components, caspase-1 activity, and concomitant overproduction of IL-1ß and IL-18 were observed in a mouse model of peritoneal fibrosis. ASC-positive and F4/80-positive cells colocalized in the subperitoneal mesothelial cell layer. These macrophages expressed high CD44 levels indicating that the CD44-positive macrophages contribute to developing peritoneal deterioration. Furthermore, intravital imaging of the peritoneal microvasculature demonstrated that the circulating CD44-positive leukocytes may contribute to peritoneal fibrosis. Bone marrow transplantation in ASC-deficient mice suppressed inflammasome activation, thereby attenuating peritoneal fibrosis in a high glucose-based PD solution-injected mouse model. Our results suggest inflammasome activation in CD44-positive macrophages may be involved in developing peritoneal fibrosis. The inflammasome-derived pro-inflammatory cytokines might therefore serve as new biomarkers for developing encapsulating peritoneal sclerosis.
Assuntos
Fibrose Peritoneal , Peritonite , Animais , Camundongos , Peritônio , Inflamassomos , Modelos Animais de Doenças , InflamaçãoRESUMO
BACKGROUND: It is well known that kidney injury is vital organ damage in Fabry disease (FD). Renin-angiotensin system (RAS) inhibitors are known to reduce proteinuria in patients with chronic kidney disease (CKD) by dilating the glomerular export arteries and reducing intraglomerular pressure. This improvement in intraglomerular pressure, although lowering the glomerular filtration rate, is thought to prevent renal damage and be renoprotective in the long term. RAS inhibitors may be effective in FD patients with proteinuria to prevent the progression of kidney disease, however, the degree to which they are used in clinical practice is unknown. METHODS: The J-CKD-DB-Ex is a comprehensive multicenter database that automatically extracts medical data on CKD patients. J-CKD-DB-Ex contains data on 187,398 patients in five medical centers. FD patients were identified by ICD-10. Clinical data and prescriptions of FD patients between January 1 of 2014, and December 31 of 2020 were used for the analysis. RESULTS: We identified 39 patients with FD from the J-CKD-DB-Ex including those with suspected FD. We confirmed 22 patients as FD. Half of the patients received RAS inhibitors. RAS inhibitors tended to be used in CKD patients with more severe renal impairment. CONCLUSIONS: This case series revealed the actual clinical practice of FD patients with CKD. In particular, we found cases in which patients had proteinuria, but were not treated with RAS inhibitors. The database was shown to be useful in assessing the clinical patterns of patients with rare diseases.
Assuntos
Doença de Fabry , Insuficiência Renal Crônica , Doença de Fabry/complicações , Doença de Fabry/tratamento farmacológico , Humanos , Masculino , Feminino , Insuficiência Renal Crônica/fisiopatologia , Japão/epidemiologia , Pessoa de Meia-Idade , Adulto , Proteinúria/tratamento farmacológico , Proteinúria/etiologia , Adulto Jovem , Bases de Dados Factuais , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Idoso , Adolescente , Taxa de Filtração Glomerular , Sistema Renina-Angiotensina/efeitos dos fármacosRESUMO
BACKGROUND: Peritoneal dialysis (PD) is an essential lifesaving treatment for end-stage renal disease. However, PD therapy is limited by peritoneal inflammation, which leads to peritoneal membrane failure because of progressive peritoneal deterioration. Peritonitis is the most common complication in patients undergoing PD. Thus, elucidating the mechanism of chronic peritoneal inflammation after PD-associated peritonitis is an urgent issue for patients undergoing PD. This first case report suggests that an increased interleukin-1ß (IL-1ß) expression in the peritoneal dialysate after healing of peritonitis can contribute to peritoneal deterioration. CASE PRESENTATION: A 64-year-old woman was diagnosed with diabetes mellitus 10 years ago and had been started on PD for end-stage renal disease. One day, the patient developed PD-associated acute peritonitis and was admitted to our hospital for treatment. Thus, treatment with antimicrobial agents was initiated for PD-associated peritonitis. Dialysate turbidity gradually disappeared after treatment with antimicrobial agents, and the number of cells in the PD fluid decreased. After 2 weeks of antimicrobial therapy, peritonitis was clinically cured, and the patient was discharged. Thereafter, the patient did not develop peritonitis; however, residual renal function tended to decline, and peritoneal function also decreased in a relatively short period. We evaluated pro-inflammatory cytokine levels before and after PD-associated peritonitis; interestingly, the levels of IL-1ß remained high in the PD fluid, even after remission of bacterial peritonitis. In addition, it correlated with decreased peritoneal function. CONCLUSIONS: This case suggests that inflammasome-derived pro-inflammatory cytokines may contribute to chronic inflammation-induced peritoneal deterioration after PD-related peritonitis is cured.
Assuntos
Anti-Infecciosos , Falência Renal Crônica , Diálise Peritoneal , Peritonite , Feminino , Humanos , Pessoa de Meia-Idade , Interleucina-1beta , Diálise Peritoneal/efeitos adversos , Peritonite/tratamento farmacológico , Peritonite/etiologia , Peritonite/diagnóstico , Citocinas/metabolismo , Soluções para Diálise , Falência Renal Crônica/complicações , Inflamação/etiologiaRESUMO
Chronic kidney disease is a common problem in the elderly and is associated with increased mortality. We have reported on the role of nitric oxide, which is generated from endothelial nitric oxide synthase (eNOS), in the progression of aged kidneys. To elucidate the role of endothelial dysfunction and the lack of an eNOS-NO pathway in ageing kidneys, we conducted experiments using eNOS and ASC-deficient mice. C57B/6 J mice (wild type (WT)), eNOS knockout (eNOS KO), and ASC knockout (ASC KO) mice were used in the present study. Then, eNOS/ASC double-knockout (eNOS/ASC DKO) mice were generated by crossing eNOS KO and ASC KO mice. These mice were sacrificed at 17-19 months old. The Masson positive area and the KIM-1 positive area tended to increase in eNOS KO mice, compared with WT mice, but not eNOS/ASC DKO mice. The COX-positive area was significantly reduced in eNOS KO mice, compared with WT and eNOS/ASC DKO mice. To determine whether inflammasomes were activated in infiltrating macrophages, the double staining of IL-18 and F4/80 was performed. IL-18 and F4/80 were found to be co-localised in the tubulointerstitial areas. Inflammasomes play a pivotal role in inflammaging in ageing kidneys. Furthermore, inflammasome activation may accelerate cellular senescence via mitochondrial dysfunction. The importance of endothelial function as a regulatory mechanism suggests that protection of endothelial function may be a potential therapeutic target.
Assuntos
Envelhecimento , Endotélio/fisiopatologia , Inflamassomos , Rim/fisiopatologia , Mitocôndrias/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Animais , Endotélio/enzimologia , Endotélio/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Mitocôndrias/fisiologia , Óxido Nítrico/metabolismo , Doenças Vasculares/fisiopatologiaRESUMO
BACKGROUND: Sodium glucose cotransporter 2 inhibitors may reduce kidney hyperfiltration, thereby preventing diabetic kidney disease progression, which may in turn reduce cardiovascular risk, including heart failure. However, the mechanisms that regulate renal function responses to sodium glucose cotransporter 2 inhibition are not yet fully understood. We explored the renal protective effects of sodium glucose cotransporter 2 inhibition with empagliflozin, with a focus on glomerular hemodynamic effects and tubuloglomerular feedback using in vivo multiphoton microscopy imaging techniques. METHODS: C57BL/6 mice and spontaneously diabetic Ins2+/Akita mice were studied. The mice were treated with empagliflozin (20 mg·kg-1·d-1) and insulin for 4 weeks, and the single-nephron glomerular filtration rate was measured using multiphoton microscope. A neuronal nitric oxide synthase inhibitor (7-nitroindazole, 20 mg·kg-1·d-1) or a cyclooxygenase-2 inhibitor (SC58236, 6 mg/L), or an A1 adenosine receptor antagonist (8-cyclopentyl-1,3-dipropylxanthine, 1 mg·kg-1·d-1) was administered to elucidate the mechanisms of tubuloglomerular feedback signaling and single-nephron glomerular filtration rate regulation. RESULTS: The urinary excretion of adenosine, nitric oxide metabolites, and the prostanoid prostaglandin E2 was also quantified. The single-nephron glomerular filtration rate in the Ins2+/Akita group was higher than in controls (C57BL/6; 4.9±1.3 nL/min versus Ins2+/Akita; 15.8±6.8 nL/min) and lower in Ins2+/Akita /empagliflozin to 8.0±3.3 nL/min (P<0.01). In vivo imaging also revealed concomitant afferent arteriolar dilation (P<0.01) and increased glomerular permeability of albumin in the Ins2+/Akita group. Empagliflozin ameliorated these changes (P<0.01). Urinary adenosine excretion in the Ins2+/Akita/empagliflozin group was higher than in Ins2+/Akita (Ins2+/Akita; 3.4±1.4 nmol/d, Ins2+/Akita/empagliflozin; 11.2±3.0 nmol/d, P<0.05), whereas nitric oxide metabolites and prostaglandin E2 did not differ. A1 adenosine receptor antagonism, but not neuronal nitric oxide synthase or cyclooxygenase-2 inhibition, blocked the effect of empagliflozin on renal function. Empagliflozin increased urinary adenosine excretion and reduced hyperfiltration via afferent arteriolar constriction, effects that were abolished by A1 adenosine receptor blockade. CONCLUSIONS: Adenosine/A1 adenosine receptor pathways play a pivotal role in the regulation of the single-nephron glomerular filtration rate via tubuloglomerular feedback mechanisms in response to sodium glucose cotransporter 2 inhibition, which may contribute to renal and cardiovascular protective effects reported in clinical trials.
Assuntos
Diabetes Mellitus Experimental/diagnóstico por imagem , Diabetes Mellitus Experimental/tratamento farmacológico , Técnicas In Vitro/métodos , Rim/fisiopatologia , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Animais , Compostos Benzidrílicos/farmacologia , Compostos Benzidrílicos/uso terapêutico , Glucosídeos/farmacologia , Glucosídeos/uso terapêutico , Humanos , Masculino , Camundongos , Inibidores do Transportador 2 de Sódio-Glicose/farmacologiaRESUMO
Endothelial dysfunction represents a predominant early feature of diabetes, rendering patients with diabetes prone to renal complications, e.g., proteinuria. Recent studies have indicated a possible role for xanthine oxidase (XO) in the pathogenesis of vascular dysfunctions associated with diabetes. In the present study, we investigated the contribution of XO activation on the progression of diabetic nephropathy in a mouse model using selective XO inhibitors. Male Ins2Akita heterozygous mice were used with wild-type mice as controls. Akita mice were treated with topiroxostat (Topi) or vehicle for 4 wk. Serum uric acid levels were significantly reduced in Akita + Topi mice compared with Akita + vehicle mice. The Akita + Topi group had a significant reduction in urinary albumin excretion compared with the Akita + vehicle group. Mesangial expansion, glomerular collagen type IV deposition, and glomerular endothelial injury (assessed by lectin staining and transmission electron microscopy) were considerably reduced in the Akita + topi group compared with the Akita + vehicle group. Furthermore, glomerular permeability was significantly higher in the Akita + vehicle group compared with the wild-type group. These changes were reduced with the administration of Topi. We conclude that XO inhibitors preserve glomerular endothelial functions and rescue compromised glomerular permeability, suggesting that XO activation plays a vital role in the pathogenesis of diabetic nephropathy.
Assuntos
Ameloblastos/metabolismo , Nefropatias Diabéticas/metabolismo , Glomérulos Renais/metabolismo , Xantina Oxidase/metabolismo , Albuminúria/metabolismo , Animais , Diabetes Mellitus Experimental/metabolismo , Modelos Animais de Doenças , Rim/metabolismo , Camundongos , NADPH Oxidases/metabolismo , Estresse Oxidativo/fisiologia , Ácido Úrico/metabolismoRESUMO
Multiple clinical studies have shown that bardoxolone methyl, a potent activator of nuclear factor erythroid 2-related factor 2 (Nrf2), is effective in increasing glomerular filtration rate in patients with chronic kidney disease. However, whether an Nrf2 activator can protect tubules from proteinuria-induced tubular damage via anti-inflammatory and antioxidative stress mechanisms is unknown. Using an Institute of Cancer Research-derived glomerulonephritis (ICGN) mouse model of nephrosis, we examined the effects of dihydro-CDDO-trifluoroethyl amide (dh404), a rodent-tolerable bardoxolone methyl analog, in protecting the tubulointerstitium; dh404 markedly suppressed tubular epithelial cell damage in the renal interstitium of ICGN mice. The tubular epithelial cells of ICGN mice showed a decrease in the size and number of mitochondria, as well as the breakdown of the crista structure, whereas the number and ultrastructure of mitochondria were maintained by the dh404 treatment. To further determine the effect of dh404 on mitochondrial function, we used human proximal tubular cells in vitro. Stimulation with albumin and free fatty acid increased mitochondrial reactive oxygen species (ROS). However, dh404 administration diminished mitochondrial ROS. Our data show that dh404 significantly reduced proteinuria-induced tubular cell mitochondrial damage, suggesting that improved redox balance and mitochondrial function and suppression of inflammation underlie the cytoprotective mechanism of Nrf2 activators, including bardoxolone methyl, in diabetic kidney disease.-Nagasu, H., Sogawa, Y., Kidokoro, K., Itano, S., Yamamoto, T., Satoh, M., Sasaki, T., Suzuki, T., Yamamoto, M., Wigley, W. C., Proksch, J. W., Meyer, C. J., Kashihara, N. Bardoxolone methyl analog attenuates proteinuria-induced tubular damage by modulating mitochondrial function.
Assuntos
Túbulos Renais Proximais/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Ácido Oleanólico/análogos & derivados , Proteinúria/complicações , Animais , Células Cultivadas , Humanos , Túbulos Renais Proximais/patologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Mitocôndrias/fisiologia , Fator 2 Relacionado a NF-E2/fisiologia , Ácido Oleanólico/farmacologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
BACKGROUND: Long-term exposure to bioincompatible peritoneal dialysate causes the loss of mesothelial cells and accumulation of matrix proteins, leading to an increase in the thickness of the submesothelial layer, thereby limiting the long-term effectiveness of peritoneal dialysis (PD). However, the detailed molecular mechanisms underlying the process of peritoneal fibrosis have not been clearly elucidated. Wnt/ß-catenin signaling pathway activation has been suggested to play a pivotal role in the development of organ fibrosis. Moreover, Klotho protein can regulate Wnt/ß-catenin signaling. We examined the role of Klotho protein in reducing peritoneal fibrosis by inhibiting Wnt/ß-catenin signaling. METHODS: The ß-catenin-activated transgenic (BAT) driving expression of nuclear ß-galactosidase reporter transgenic (BAT-LacZ) mice, the alpha-Klotho gene under control of human elongation factor 1 alpha promoter [Klotho transgenic (KLTG) and C57BL/6 background] and C57BL/6 mice [wild-type (WT)] were used. The mice received daily intraperitoneal (i.p.) injections of 4.25% glucose with lactate (PD solution) or saline as a control for 4 weeks. Other mice received daily i.p. injections of the same volume of saline (normal control). RESULTS: After exposure to PD, Wnt signal activation was observed on the peritoneal mesothelial cells in WT-PD mice. The peritoneal fibrosis was also accelerated in WT-PD mice. The protein expression of ß-catenin and Wnt-inducible genes were also remarkably increased in WT-PD mice. On the other hand, KLTG-PD mice attenuated activation of Wnt/ß-catenin signaling after exposure to PD and ameliorated the progression of peritoneal fibrosis. CONCLUSIONS: Overexpression of Klotho protein protects the peritoneal membrane through attenuation of the Wnt/ß-catenin signaling pathway. The availability of recombinant Klotho protein would provide a novel potential therapeutic target in peritoneal fibrosis.
Assuntos
Glucuronidase/fisiologia , Fibrose Peritoneal/terapia , Proteínas Wnt/antagonistas & inibidores , beta Catenina/antagonistas & inibidores , Animais , Humanos , Proteínas Klotho , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Diálise Peritoneal/efeitos adversos , Fibrose Peritoneal/etiologia , Fibrose Peritoneal/patologia , Proteínas Wnt/metabolismo , beta Catenina/metabolismoRESUMO
AIM: Acute kidney injury (AKI) is associated with chronic kidney disease, as well as high mortality, but effective treatments for AKI are still lacking. A recent study reported the prevention of renal injury, such as ischemia-reperfusion injury, by 5-aminolevulinic acid (ALA), which induces an antioxidant effect. The current study aimed to investigate the effect of ALA in a rhabdomyolysis-induced mouse model of AKI created by intramuscular injection of 50% glycerol. METHODS: Rhabdomyolysis-induced AKI was induced by an intramuscular injection of glycerol (5 mL/kg body weight) into mice. Administration of ALA (30 mg/kg, by gavage) was started from 48 h before or 24 h after glycerol injection. The mice were sacrificed at 72 h after glycerol injection. The roles of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), which is one of the Nrf2-related antioxidants, were further investigated through in vivo and in vitro methods. RESULTS: 5-aminolevulinic acid markedly reduced renal dysfunction and tubular damage in mice with rhabdomyolysis-induced AKI. ALA administration decreased oxidative stress, macrophage infiltration, and inflammatory cytokines and apoptosis. The expression of Nrf2 was upregulated by ALA administration. However, administration of Zinc protoporphyrin-9 (ZnPPIX) to inhibit HO-1 activity did not abolish these improvements by ALA. The expression of Nrf2-associated antioxidant factors other than HO-1 was also increased. CONCLUSION: These findings indicate that ALA exerts its antioxidant activity via Nrf2-associated antioxidant factors to provide a renoprotective effect against rhabdomyolysis-induced AKI.
Assuntos
Injúria Renal Aguda/prevenção & controle , Ácido Aminolevulínico/farmacologia , Antioxidantes/farmacologia , Túbulos Renais/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/agonistas , Rabdomiólise/prevenção & controle , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/patologia , Animais , Apoptose/efeitos dos fármacos , Células Cultivadas , Citocinas/metabolismo , Citoproteção , Modelos Animais de Doenças , Glicerol , Heme Oxigenase-1/metabolismo , Humanos , Mediadores da Inflamação/metabolismo , Túbulos Renais/metabolismo , Túbulos Renais/patologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Macrófagos/patologia , Masculino , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Rabdomiólise/induzido quimicamente , Rabdomiólise/metabolismo , Rabdomiólise/patologia , Transdução de Sinais/efeitos dos fármacosRESUMO
Increased generation of reactive oxygen species (ROS) is a common denominative pathogenic mechanism underlying vascular and renal complications in diabetes mellitus. Endothelial NAD(P)H oxidase is a major source of vascular ROS, and it has an important role in endothelial dysfunction. We hypothesized that activation of endothelial NAD(P)H oxidase initiates and worsens the progression of diabetic nephropathy, particularly in the development of albuminuria. We used transgenic mice with endothelial-targeted overexpression of the catalytic subunit of NAD(P)H oxidase, Nox2 (NOX2TG). NOX2TG mice were crossed with Akita insulin-dependent diabetic (Akita) mice that develop progressive hyperglycemia. We compared the progression of diabetic nephropathy in Akita versus NOX2TG-Akita mice. NOX2TG-Akita mice and Akita mice developed significant albuminuria above the baseline at 6 and 10 weeks of age, respectively. Compared with Akita mice, NOX2TG-Akita mice exhibited higher levels of NAD(P)H oxidase activity in glomeruli, developed glomerular endothelial perturbations, and attenuated expression of glomerular glycocalyx. Moreover, in contrast to Akita mice, the NOX2TG-Akita mice had numerous endothelial microparticles (blebs), as detected by scanning electron microscopy, and increased glomerular permeability. Furthermore, NOX2TG-Akita mice exhibited distinct phenotypic changes in glomerular mesangial cells expressing α-smooth muscle actin, and in podocytes expressing increased levels of desmin, whereas the glomeruli generated increased levels of ROS. In conclusion, activation of endothelial NAD(P)H oxidase in the presence of hyperglycemia initiated and exacerbated diabetic nephropathy characterized by the development of albuminuria. Moreover, ROS generated in the endothelium compounded glomerular dysfunctions by altering the phenotypes of mesangial cells and compromising the integrity of the podocytes.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Nefropatias Diabéticas/metabolismo , NADPH Oxidases/metabolismo , Animais , Glicemia/análise , Diabetes Mellitus Experimental/enzimologia , Nefropatias Diabéticas/enzimologia , Feminino , Taxa de Filtração Glomerular/fisiologia , Glomérulos Renais/química , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Masculino , Camundongos , Podócitos/química , Espécies Reativas de Oxigênio/metabolismoRESUMO
High levels of aldosterone impair renal function by activating proinflammatory and profibrotic pathways. However, the molecular mechanism underlying aldosterone-induced inflammation and fibrosis is unknown. Inflammasome activation contributes to chronic kidney disease. We hypothesized that aldosterone induces renal tubulointerstitial inflammation and fibrosis by activating the inflammasome. Infusing wild-type mice with aldosterone (0.25 mg/kg/d) caused tubulointerstitial damage, increased expression of inflammasome components, caspase 1 activation, and overproduction of IL-1ß and IL-18. These changes were suppressed by eplerenone treatment (100 mg/kg/d) in wild-type mice or in mice deficient in apoptosis-associated speck-like protein with a caspase-recruitment domain (ASC). Caspase 1-positive and F4/80-positive cells colocalized in the interstitium. Bone marrow transplantation using ASC-deficient mice indicated that inflammasome activation in macrophages mediated aldosterone-induced renal fibrosis. IL-18 was detected in culture supernatants of macrophages treated with aldosterone, and mitochondria-derived reactive oxygen species activated the inflammasome in these macrophages. Our results indicate that exposure of macrophages to high levels of aldosterone resulted in the activation of inflammasomes via the mitochondria-derived reactive oxygen species. Thus, inflammasome activation in macrophages may serve as a new therapeutic target for chronic kidney disease.
Assuntos
Aldosterona/efeitos adversos , Inflamassomos/metabolismo , Nefropatias/metabolismo , Transdução de Sinais/efeitos dos fármacos , Aldosterona/farmacologia , Animais , Proteínas Reguladoras de Apoptose/biossíntese , Proteínas Reguladoras de Apoptose/genética , Proteínas Adaptadoras de Sinalização CARD , Caspase 1/biossíntese , Caspase 1/genética , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/genética , Fibrose , Regulação da Expressão Gênica/efeitos dos fármacos , Inflamassomos/genética , Interleucina-18/biossíntese , Interleucina-18/genética , Interleucina-1beta/biossíntese , Interleucina-1beta/genética , Nefropatias/induzido quimicamente , Nefropatias/genética , Nefropatias/patologia , Macrófagos/metabolismo , Macrófagos/patologia , Masculino , Camundongos , Camundongos Knockout , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genéticaRESUMO
BACKGROUND: Expression of klotho, the renoprotective anti-aging gene, is decreased in diabetic model kidneys. We hypothesized that klotho protein attenuates renal hypertrophy and glomerular injury in a mouse model of diabetic nephropathy. METHODS: Klotho transgenic (KLTG) mice were crossed with spontaneously diabetic Ins2Akita (AKITA) mice. Glomerular morphology, macrophage infiltration, urinary albumin excretion and urinary 8-hydroxy-2-deoxy guanosine excretion were examined. In vitro, human glomerular endothelial cells were stimulated with high glucose with or without recombinant klotho, and calpain activity and proinflammatory cytokine expressions were measured. RESULTS: We found that klotho protein overexpression attenuates renal hypertrophy and glomerular injury in this mouse model of diabetic nephropathy. Klotho overexpression attenuated renal hypertrophy, albuminuria, glomerular mesangial expansion, and endothelial glycocalyx loss in the AKITA mice. AKITA mice exhibit high levels of urinary 8-hydroxy-2-deoxy guanosine excretion. In the presence of klotho overexpression, this effect was reversed. In addition, the glomerular macrophage infiltration characteristic of AKITA mice was attenuated in KLTG-AKITA mice. In human glomerular endothelial cells, high glucose induced calpain activity. This effect was suppressed by expression of recombinant klotho, which also suppressed the induction of proinflammatory cytokines. CONCLUSION: Our data suggest klotho protein protects against diabetic nephropathy through multiple pathways.
Assuntos
Diabetes Mellitus/metabolismo , Nefropatias Diabéticas/prevenção & controle , Glucuronidase/metabolismo , Glomérulos Renais/metabolismo , 8-Hidroxi-2'-Desoxiguanosina , Albuminúria/genética , Albuminúria/metabolismo , Albuminúria/prevenção & controle , Animais , Biomarcadores/urina , Calpaína/genética , Calpaína/metabolismo , Células Cultivadas , Desoxiguanosina/análogos & derivados , Desoxiguanosina/urina , Diabetes Mellitus/genética , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Genótipo , Glucose/metabolismo , Glucuronidase/genética , Humanos , Hipertrofia , Mediadores da Inflamação/metabolismo , Glomérulos Renais/patologia , Proteínas Klotho , Macrófagos/metabolismo , Macrófagos/patologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fenótipo , TransfecçãoRESUMO
BACKGROUND: The prevalence of gastroesophageal reflux disease (GERD) symptoms has not been investigated in patients on maintenance hemodialysis in Japan, and few studies have reported the effect of proton pump inhibitors (PPIs) in hemodialysis patients with GERD symptoms. Here, we investigated the prevalence of GERD symptoms and the effects of the PPI esomeprazole on the quality of life related to reflux and dyspepsia in patients on maintenance hemodialysis. METHODS: This was a cross-sectional/cohort study of hemodialysis outpatients implemented in 10 Japanese medical facilities from October 2012 to March 2014. The trial was registered in the UMIN Clinical Trial Registry (UMIN000009124). RESULTS: Forty-one of 385 patients (11%) reported GERD symptoms on the Global Overall Symptom (GOS) questionnaire. Multivariate logistic regression analysis identified the independent prognostic factors for GERD symptoms as a history of gastric ulcer and use of sevelamer hydrochloride or calcium polystyrene sulfonate. Participants with GERD symptoms completed the Quality of Life in Reflux and Dyspepsia, Japanese version (QOLRAD-J) questionnaire and were assigned to receive 4-week esomeprazole treatment (20 mg/day). This PPI therapy significantly improved all QOLRAD-J domains in the full analysis set (n = 28) and improved the GERD symptoms listed in the GOS questionnaire. Significantly impaired disease-specific quality of life (QOL) in the QOLRAD-J domains was observed in 44.4-74.1% of patients who had symptoms before treatment. The mean GOS and QOLRAD-J scores correlated significantly. CONCLUSION: Therapy with 20 mg/day esomeprazole appears to be efficacious for improving disease-specific QOL and GERD symptoms in Japanese patients on maintenance hemodialysis.
Assuntos
Dispepsia/tratamento farmacológico , Esomeprazol/uso terapêutico , Refluxo Gastroesofágico/tratamento farmacológico , Nefropatias/terapia , Inibidores da Bomba de Prótons/uso terapêutico , Qualidade de Vida , Diálise Renal , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Dispepsia/diagnóstico , Dispepsia/epidemiologia , Dispepsia/psicologia , Esomeprazol/efeitos adversos , Feminino , Refluxo Gastroesofágico/diagnóstico , Refluxo Gastroesofágico/epidemiologia , Refluxo Gastroesofágico/psicologia , Humanos , Japão/epidemiologia , Nefropatias/diagnóstico , Nefropatias/epidemiologia , Nefropatias/psicologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Prevalência , Inibidores da Bomba de Prótons/efeitos adversos , Indução de Remissão , Inquéritos e Questionários , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: Long-term peritoneal dialysis (PD) causes peritoneal dysfunction and structural alterations, eventually leading to peritoneal fibrosis. The endothelial nitric oxide synthase (eNOS)-NO signaling pathway contributes to the progression of organ fibrosis. However, it remains unknown whether NO signaling is involved in the process of peritoneal fibrosis. We evaluated the role of the eNOS-NO signaling pathway in the development of peritoneal fibrosis and whether stimulation of soluble guanylate cyclase (sGC), a downstream effector of NO, could attenuate peritoneal fibrosis. METHODS: We used wild-type (WT) and eNOS-deficient mice (eNOSKO). The mice underwent mechanical peritoneal stripping-induced peritoneal fibrosis at day 0. At 3, 7, 14, and 28 days after peritoneal stripping, the mice were killed. In some eNOSKO mice, the sGC stimulator Bay 41-2272 was administered by intraperitoneal injection. RESULTS: In WT mice, granulomatous tissue formation was observed in the submesothelial area at days 3 and 7. After day 7, the peritoneal membrane thickness gradually decreased and peritoneal tissue was repaired with leaving only slight fibrosis at day 28. However, eNOSKO mice demonstrated more progression of peritoneal fibrosis than WT mice at 28 days after peritoneal stripping. Expression of vimentin in the thickened peritoneum was prolonged after day 7 in eNOSKO mice. Treatment with Bay 41-2272 significantly attenuated peritoneal vimentin expression and fibrosis in the eNOSKO mice. CONCLUSIONS: Disruption of the eNOS-NO signaling pathway exacerbates peritoneal fibrosis by delaying wound healing. sGC stimulation may be a useful therapy for prevention of peritoneal fibrosis.
Assuntos
Guanilato Ciclase/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico/metabolismo , Fibrose Peritoneal/enzimologia , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Fibrose , Isoenzimas/metabolismo , Queratinas/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Diálise Peritoneal/efeitos adversos , Fibrose Peritoneal/etiologia , Fibrose Peritoneal/prevenção & controle , Peritônio/enzimologia , Peritônio/patologia , Transdução de Sinais , Guanilil Ciclase Solúvel , Vimentina/metabolismoRESUMO
AIM: Hypertension contributes critically to the development of renal arteriolosclerosis in chronic kidney disease (CKD), but the impact of vascular function indexes including central blood pressure on renal arteriolosclerosis has not been investigated. We determined whether vascular function indexes were related to renal arteriolosclerosis and renal clinical outcomes in CKD. METHODS: This cross-sectional study was implemented in our hospital. Subjects were in-patients with CKD aged ≥20 years who underwent a renal biopsy. Vascular function indexes included central systolic blood pressure (SBP), cardio-ankle vascular index (CAVI), and renal resistive index. Central SBP was measured non-invasively using an automated device. Arteriolosclerosis was assessed histologically. Renal clinical outcomes included estimated glomerular filtration rate using serum creatinine (eGFRcreat) or cystatin C (eGFRcys), and the urinary albumin-creatinine ratio. RESULTS: Among vascular function indexes, central SBP was weakly correlated with renal arteriolosclerosis (n = 55). Renal arteriolosclerosis was increased in hypertensive or hyperuricaemic patients, and negatively correlated with serum high-density lipoprotein (HDL) cholesterol and eGFRcys, which were independent risk factors for renal arteriolosclerosis in a stepwise multivariate regression analysis. Of the vascular function indexes, CAVI showed the strongest correlation with all renal clinical outcomes. Central SBP was correlated with only urinary albumin-creatinine ratio, while renal resistive index was correlated with eGFRcreat and urinary albumin-creatinine ratio. CONCLUSION: Decreased serum HDL cholesterol was independently and most closely associated with renal arteriolosclerosis. Of the vascular function indexes, CAVI had the greatest impact on renal clinical outcomes, although it was not associated with renal arteriolosclerosis.
Assuntos
Arteriolosclerose/fisiopatologia , Hemodinâmica , Rim/fisiopatologia , Obstrução da Artéria Renal/fisiopatologia , Insuficiência Renal Crônica/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Índice Tornozelo-Braço , Arteriolosclerose/diagnóstico , Biomarcadores/sangue , Biópsia , Pressão Sanguínea , Creatinina/sangue , Estudos Transversais , Cistatina C/sangue , Feminino , Taxa de Filtração Glomerular , Humanos , Hiperlipidemias/fisiopatologia , Hipertensão/fisiopatologia , Hiperuricemia/fisiopatologia , Rim/patologia , Masculino , Pessoa de Meia-Idade , Obstrução da Artéria Renal/diagnóstico , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/diagnóstico , Resistência Vascular , Adulto JovemRESUMO
OBJECTIVE: Angiotensin II causes potent increases in systemic and local pressure through its vasoconstrictive effect. Despite the importance of angiotensin II for local blood flow regulation, whether angiotensin II regulates the pancreatic islet microcirculation remains incompletely understood. We hypothesized that angiotensin II directly regulates the pancreatic islet microcirculation and thereby regulates insulin secretion. The aims of this study were to develop a new technique to visualize pancreatic islet hemodynamic changes in vivo and to analyze changes in islet circulation induced by angiotensin II or an angiotensin type 1 receptor blocker. METHODS: Using an in vivo imaging method, we observed the pancreatic islet microcirculation. Various doses of angiotensin II or an angiotensin type 1 receptor blocker were injected intravenously, and changes in islet microcirculation were observed. Glucose-stimulated insulin secretion from the pancreas was measured from the hepatic portal vein. RESULTS: We identified islet microcirculation using a fluorescent dye. Angiotensin II significantly induced blood vessel contraction in the islets in a dose-dependent manner. In contrast, the angiotensin type 1 receptor blocker induced vasodilation. Glucose-stimulated insulin secretion was decreased by angiotensin II infusion. CONCLUSIONS: These results show that angiotensin II is involved in the regulation of pancreatic islet microcirculation and insulin secretion.
Assuntos
Angiotensina II/farmacologia , Insulina/metabolismo , Ilhotas Pancreáticas , Vasoconstritores/farmacologia , Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Animais , Secreção de Insulina , Ilhotas Pancreáticas/irrigação sanguínea , Ilhotas Pancreáticas/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Vasoconstrição/efeitos dos fármacosRESUMO
Abstract Hypertensive patients have a higher incidence of new-onset diabetic mellitus than normotensive subjects, and we hypothesized that hypertension induces morphological changes in islets via vascular injury. To test our hypothesis, we administrated hydralazine or irbesartan to spontaneously hypertensive stroke-prone (SHRsp) rats. A greater islet fibrosis was observed in SHRsp rats compared with controls, and irbesartan significantly ameliorated the fibrosis. High fat diet induced glucose intorelance in SHRsp rats and irbesartan but not hydralazine improved glucose torelance. We demonstrate islet morphological changes in hypertensive rats, and our data suggest that angiotensin receptor blockers have the potential to prevent islet injury.
Assuntos
Anti-Hipertensivos/farmacologia , Hipertensão/complicações , Ilhotas Pancreáticas/patologia , Estado Pré-Diabético/complicações , Lesões do Sistema Vascular , Animais , Compostos de Bifenilo/farmacologia , Pressão Sanguínea/fisiologia , Modelos Animais de Doenças , Hidralazina/farmacologia , Hipertensão/fisiopatologia , Irbesartana , Ilhotas Pancreáticas/efeitos dos fármacos , Masculino , Ratos Endogâmicos SHR , Tetrazóis/farmacologia , Lesões do Sistema Vascular/induzido quimicamenteRESUMO
In diabetes, endothelial nitric oxide synthase (eNOS) produces superoxide anion rather than nitric oxide, referred to as "eNOS uncoupling," which may contribute to endothelial dysfunction, albuminuria, and diabetic nephropathy. Reduced levels of endothelium-derived tetrahydrobiopterin (BH4), an essential cofactor for eNOS, promote eNOS uncoupling. Accelerated degradation of guanosine triphosphate cyclohydrolase I (GTPCH I), the rate-limiting enzyme in BH4 biosynthesis, also occurs in diabetes, suggesting that GTPCH I may have a role in diabetic microvascular disease. Here, we crossed endothelium-dominant GTPCH I transgenic mice with Ins2(+/Akita) diabetic mice and found that endothelial overexpression of GTPCH I led to higher levels of intrarenal BH4 and lower levels of urinary albumin and reactive oxygen species compared with diabetic control mice. Furthermore, GTPCH I overexpression attenuated the hyperpermeability of macromolecules observed in diabetic control mice. In addition, we treated Ins2(+/Akita) mice with metformin, which activates AMP-activated protein kinase (AMPK) and thereby slows the degradation of GTPCH I; despite blood glucose levels that were similar to untreated mice, those treated with metformin had significantly less albuminuria. Similarly, in vitro, treating human glomerular endothelial cells with AMPK activators attenuated glucose-induced reductions in phospho-AMPK, GTPCH I, and coupled eNOS. Taken together, these data suggest that maintenance of endothelial GTPCH I expression and the resulting improvement in BH4 biosynthesis ameliorate diabetic nephropathy.
Assuntos
Biopterinas/análogos & derivados , Diabetes Mellitus Experimental/metabolismo , Nefropatias Diabéticas/metabolismo , GTP Cicloidrolase/metabolismo , Albuminúria/metabolismo , Animais , Biopterinas/metabolismo , Linhagem Celular , Endotélio Vascular/metabolismo , Humanos , Metformina/farmacologia , Camundongos , Óxido Nítrico Sintase Tipo III/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
There are cases in which CKD progression is difficult to evaluate, because the changes in estimated glomerular filtration rate (eGFR) and proteinuria sometimes show opposite directions as CKD progresses. Indices and models that enable the easy and accurate risk prediction of end-stage-kidney disease (ESKD) are indispensable to CKD therapy. In this study, we investigated whether a CKD stage coordinate transformed into a vector field (CKD potential model) accurately predicts ESKD risk. Meta-analysis of large-scale cohort studies of CKD patients in PubMed was conducted to develop the model. The distance from CKD stage G2 A1 to a patient's data on eGFR and proteinuria was defined as r. We developed the CKD potential model on the basis of the data from the meta-analysis of three previous cohort studies: ESKD risk = exp(r). Then, the model was validated using data from a cohort study of CKD patients in Japan followed up for three years (n = 1,564). Moreover, the directional derivative of the model was developed as an index of CKD progression velocity. For ESKD prediction in three years, areas under the receiver operating characteristic curves (AUCs) were adjusted for baseline characteristics. Cox proportional hazards models with spline terms showed the exponential association between r and ESKD risk (p<0.0001). The CKD potential model more accurately predicted ESKD with an adjusted AUC of 0.81 (95% CI 0.76, 0.87) than eGFR (p<0.0001). Moreover, the directional derivative of the model showed a larger adjusted AUC for the prediction of ESKD than the percent eGFR change and eGFR slope (p<0.0001). Then, a chart of the transformed CKD stage was developed for implementation in clinical settings. This study indicated that the transformed CKD stage as a vector field enables the easy and accurate estimation of ESKD risk and CKD progression and suggested that vector analysis is a useful tool for clinical studies of CKD and its related diseases.