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1.
J Pharmacol Sci ; 156(1): 9-18, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39068035

RESUMO

Necroptosis, necrosis characterized by RIPK3-MLKL activation, has been proposed as a mechanism of doxorubicin (DOX)-induced cardiomyopathy. We showed that rapamycin, an mTORC1 inhibitor, attenuates cardiomyocyte necroptosis. Here we examined role of MLKL in DOX-induced myocardial damage and protective effects of rapamycin. Cardiomyopathy was induced in mice by intraperitoneal injections of DOX (10 mg/kg, every other day) and followed for 7 days. DOX-treated mice showed a significant decline in LVEF assessed by cardiac MRI (45.5 ± 5.1% vs. 65.4 ± 4.2%), reduction in overall survival rates, and increases in myocardial RIPK3 and MLKL expression compared with those in vehicle-treated mice, and those changes were prevented by administration of rapamycin (0.25 mg/kg) before DOX injection. In immunohistochemical analyses, p-MLKL signals were detected in the cardiomyocytes of DOX-treated mice, and the signals were reduced by rapamycin. Mlkl+/- and Mlkl-/- mice were similarly resistant to DOX-induced cardiac dysfunction, indicating that a modest reduction in MLKL level is sufficient to prevent the development of DOX-induced cardiomyopathy. However, evidence of cardiomyocyte necrosis assessed by C9 immunostaining, presence of replacement fibrosis, and electron microscopic analyses was negligible in the myocardium of DOX-treated mice. Thus, MLKL-mediated signaling contributes to DOX-induced cardiac dysfunction primarily by a necrosis-independent mechanism, which is inhibitable by rapamycin.


Assuntos
Cardiomiopatias , Doxorrubicina , Camundongos Endogâmicos C57BL , Miócitos Cardíacos , Necroptose , Proteínas Quinases , Proteína Serina-Treonina Quinases de Interação com Receptores , Sirolimo , Animais , Doxorrubicina/efeitos adversos , Proteínas Quinases/metabolismo , Sirolimo/farmacologia , Cardiomiopatias/induzido quimicamente , Cardiomiopatias/prevenção & controle , Cardiomiopatias/patologia , Cardiomiopatias/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Necroptose/efeitos dos fármacos , Masculino , Camundongos , Antibióticos Antineoplásicos/efeitos adversos , Antibióticos Antineoplásicos/toxicidade
2.
Clin Exp Nephrol ; 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39168886

RESUMO

BACKGROUND: A streamlined and effective renal biopsy technique is essential for all nephrologists, particularly those who are less experienced, such as residents. Herein, we report the efficacy of a Straightforward and Immediate ultrasound-guided kidney biopsy using a Guide Needle (SIGN) technique, which allows operators to insert a biopsy gun through a guide needle placed into the fascia of the posterior abdominal wall. METHODS: A retrospective cross-sectional study was conducted at a nephrology training institution to compare the time spent on the procedure and the number of glomeruli obtained between a group using the SIGN (n = 81) and a group using the conventional ultrasound-guided kidney biopsy technique with a needle guide device (n = 143). RESULTS: The median procedure time in the SIGN group (2 min, interquartile range [IQR]: 1-3 min) was significantly shorter than that in the conventional group (3 min, IQR: 2-4 min) (P < 0.001). Multivariable linear regression and logistic regression analyses adjusted for covariates, including operators (board-certificated nephrologists or nephrology residents), showed that the use of the SIGN technique was independently associated with a high number of glomeruli obtained and a procedure time above 2 min as the median value (odds ratio: 0.17, 95% confidence interval CI 0.09-0.34). The prevalence of complications was comparable between the two groups (P = 0.681). CONCLUSION: The SIGN technique reduces the procedure time and obtains adequate biopsy tissue regardless of the operator's experience. SIGN can be applied in nephrology training programs and used as a standard biopsy technique.

3.
Circ J ; 88(1): 10-19, 2023 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-37813601

RESUMO

BACKGROUND: The renin-angiotensin system (RAS) activation is a proposed mechanism of muscle wasting (MW i.e., reduction in muscle mass). Although we reported that RAS inhibitors (RASIs) were associated with lower prevalence of MW in heart failure (HF) patients, the relationship between mineralocorticoid receptor (MR) signaling and MW has not been analyzed.Methods and Results: We analyzed data from 320 consecutive Japanese HF patients who underwent dual-energy X-ray absorptiometry scanning for assessment of appendicular skeletal muscle mass index (ASMI). In multiple linear regression analyses, plasma renin activity (PRA) was negatively correlated with ASMI in patients not receiving RASIs, indicating an untoward role of the RAS in MW. Results of analysis of covariance in which risk factors of MW served as covariates showed that use of MR antagonists (MRAs) was associated with lower ASMI and higher PRA in the non-RASIs group. The close relationship between use of MRAs and lower ASMI or higher PRA in the non-RASIs group was confirmed in analyses in which the differences in baseline characteristics between users and non-users of MRAs were minimized by using an inverse probability of treatment weighting. CONCLUSIONS: Increased PRA by MR inhibition without concurrent RAS inhibition, possibly contributing to upregulation of angiotensin II signaling, may be associated with reduction in muscle mass.


Assuntos
Insuficiência Cardíaca , Antagonistas de Receptores de Mineralocorticoides , Humanos , Antagonistas de Receptores de Mineralocorticoides/efeitos adversos , Sistema Renina-Angiotensina , Insuficiência Cardíaca/tratamento farmacológico , Anti-Hipertensivos , Inibidores Enzimáticos/farmacologia , Músculos , Antagonistas de Receptores de Angiotensina/efeitos adversos
4.
J Pharmacol Sci ; 151(2): 134-143, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36707179

RESUMO

Accumulating evidence suggests that necroptosis of cardiomyocytes contributes to cardiovascular diseases. Lethal disruption of the plasma membrane in necroptosis is induced by oligomers of mixed lineage kinase domain-like (MLKL) that is translocated to the membrane from the cytosol. However, the role played by cytoplasmic-nuclear shuttling of MLKL is unclear. Here, we tested the hypothesis that translocation of MLKL to the nucleus promotes the necroptosis of cardiomyocytes. Activation of the canonical necroptotic signaling pathway by a combination of TNF-α and zVAD (TNF/zVAD) increased nuclear MLKL levels in a RIP1-activity-dependent manner in H9c2 cells, a rat cardiomyoblast cell line. By use of site-directed mutagenesis, we found a nuclear export signal sequence in MLKL and prepared its mutant (MLKL-L280/283/284A), though a search for a nuclear import signal was unsuccessful. MLKL-L280/283/284A localized to both the cytosol and the nucleus. Expression of MLKL-L280/283/284A induced necroptotic cell death, which was attenuated by GppNHp, an inhibitor of Ran-mediated nuclear import, but not by inhibition of RIP1 activity or knockdown of RIP3 expression. GppNHp partly suppressed H9c2 cell death induced by TNF/zVAD treatment. These results suggest that MLKL that is translocated to the nucleus via RIP1-mediated necroptotic signaling enhances the necroptosis of cardiomyocytes through a RIP1-/RIP3-independent mechanism.


Assuntos
Proteínas Quinases , Proteína Serina-Treonina Quinases de Interação com Receptores , Ratos , Animais , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Necroptose , Morte Celular , Transdução de Sinais , Necrose , Apoptose
5.
BMC Nephrol ; 24(1): 370, 2023 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-38093211

RESUMO

BACKGROUND: Sarcoidosis affects multiple organs and exhibits diverse clinical manifestations. Although tubulointerstitial nephritis is a known feature of renal involvement, necrotizing vasculitis is rare. Furthermore, prostate involvement with urinary retention is unusual in patients with sarcoidosis. Here, we report a case of systemic sarcoidosis with a rare combination of manifestations and different acute kidney injuries. CASE PRESENTATION: A 66-year-old man developed sudden urinary retention and fever. He was diagnosed with prostatitis and admitted to our hospital. An indwelling urethral catheter was inserted, and antimicrobial therapy was initiated; however, the prostatitis was refractory. Computed tomography revealed enlarged mediastinal lymph nodes. Analysis of transbronchoscopic lymph node and prostate biopsies showed epithelioid cell granulomas, suggesting systemic sarcoidosis. During the clinical course, the serum creatinine level rapidly increased to 2.36 mg/dL without oliguria. A kidney biopsy revealed tubulointerstitial injury with moderate lymphohistiocytic infiltration and small-vessel vasculitis in the interstitium. Following oral administration of 60 mg/day prednisolone, the patient's renal function immediately improved, and urinary retention did not recur. CONCLUSIONS: To the best of our knowledge, this is the first reported case of sarcoidosis with two unusual complications. Given its clinical course and pathology, this case is clinically valuable.


Assuntos
Nefrite Intersticial , Prostatite , Sarcoidose , Retenção Urinária , Vasculite , Masculino , Humanos , Idoso , Próstata/patologia , Prostatite/complicações , Retenção Urinária/complicações , Nefrite Intersticial/complicações , Nefrite Intersticial/diagnóstico , Nefrite Intersticial/tratamento farmacológico , Sarcoidose/diagnóstico , Sarcoidose/diagnóstico por imagem , Granuloma/complicações , Granuloma/diagnóstico por imagem , Vasculite/complicações , Progressão da Doença
6.
Int Heart J ; 64(1): 36-43, 2023 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-36725078

RESUMO

Preserved urinary excretion of aquaporin 2, an index for the function of vasopressin V2 receptor (V2-R), has been reported to predict a favorable response of heart failure patients to treatment with tolvaptan. In this study, we investigated the long-term effects of tolvaptan treatment on clinical outcomes and V2-R function in patients with acute decompensated heart failure (ADHF). We enrolled 90 consecutive patients who were hospitalized in Sapporo Medical University Hospital for ADHF and treated with tolvaptan in the BOREAS-ADHF registry and analyzed patients who continued taking tolvaptan after discharge. The effect of tolvaptan treatment on rehospitalization for HF or death was investigated according to whether the V2-R function was preserved (first morning urine osmolarity ≥ 352 mOsm/L, High-Uosm) or impaired (Uosm < 352 mOsm/L, Low-Uosm). During a median follow-up period of 443 days, significantly fewer patients in the High-Uosm group experienced adverse events than did patients in the Low-Uosm group (P < 0.001). Among the patients with High-Uosm, early commencement of tolvaptan administration (on or before day 7 of hospitalization, Early/High-Uosm) significantly reduced adverse events compared to late administration (after day 7 of hospitalization, Late/High-Uosm). Uosm measured during the long-term follow-up period after discharge was significantly reduced compared to that before commencement of tolvaptan administration in the Late/High-Uosm group (from 468 ± 88 to 395 ± 108 mOsm, -18.3 ± 19.6%, P < 0.05) but not in the Early/High-Uosm group (from 478 ± 115 to 455 ± 133 mOsm, -0.50 ± 35.3%, P = 0.66). These findings indicate that early commencement and long-term continuation of tolvaptan treatment attenuate functional impairment of V2-R and improve clinical outcomes in ADHF patients with preserved V2-R function.


Assuntos
Insuficiência Cardíaca , Receptores de Vasopressinas , Humanos , Tolvaptan/uso terapêutico , Receptores de Vasopressinas/uso terapêutico , Antagonistas dos Receptores de Hormônios Antidiuréticos/uso terapêutico , Benzazepinas/uso terapêutico , Vasopressinas
7.
J Mol Cell Cardiol ; 154: 21-31, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33548240

RESUMO

BACKGROUND: We previously reported that upregulated AMP deaminase (AMPD) contributes to diastolic ventricular dysfunction via depletion of the adenine nucleotide pool in a rat model of type 2 diabetes (T2DM), Otsuka Long-Evans-Tokushima Fatty rats (OLETF). Meanwhile, AMPD promotes the formation of substrates of xanthine oxidoreductase (XOR), which produces ROS as a byproduct. Here, we tested the hypothesis that a functional link between upregulated AMPD and XOR is involved in ventricular dysfunction in T2DM rats. METHODS AND RESULTS: Pressure-volume loop analysis revealed that pressure overloading by phenylephrine infusion induced severer left ventricular diastolic dysfunction (tau: 14.7 ± 0.8 vs 12.5 ± 0.7 msec, left ventricular end-diastolic pressure: 18.3 ± 1.5 vs 12.2 ± 1.3 mmHg, p < 0.05) and ventricular-arterial uncoupling in OLETF than in LETO, non-diabetic rats, though the baseline parameters were comparable in the two groups. While the pressure overload did not affect AMPD activity, it increased XOR activity both in OLETF and LETO, with OLETF showing significantly higher XOR activity than that in LETO (347.2 ± 17.9 vs 243.2 ± 6.1 µg/min/mg). Under the condition of pressure overload, myocardial ATP level was lower, and levels of xanthine and uric acid were higher in OLETF than in LETO. Addition of exogenous inosine, a product of AMP deamination, to the heart homogenates augmented XOR activity. OLETF showed 68% higher tissue ROS levels and 47% reduction in mitochondrial state 3 respiration compared with those in LETO. Overexpression of AMPD3 in H9c2 cells elevated levels of hypoxanthine and ROS and reduced the level of ATP. Inhibition of XOR suppressed the production of tissue ROS and mitochondrial dysfunction and improved ventricular function under the condition of pressure overload in OLETF. CONCLUSIONS: The results suggest that increases in the activity of XOR and the formation of XOR substrates by upregulated AMPD contribute to ROS-mediated diastolic ventricular dysfunction at the time of increased cardiac workload in diabetic hearts.


Assuntos
AMP Desaminase/metabolismo , Diabetes Mellitus Tipo 2/complicações , Cardiopatias/etiologia , Cardiopatias/metabolismo , Cardiopatias/fisiopatologia , Disfunção Ventricular Esquerda/fisiopatologia , Xantina Desidrogenase/efeitos adversos , Animais , Biomarcadores , Glicemia , Cardiomiopatias/etiologia , Cardiomiopatias/metabolismo , Cardiomiopatias/patologia , Cardiomiopatias/fisiopatologia , Diabetes Mellitus Tipo 2/metabolismo , Modelos Animais de Doenças , Suscetibilidade a Doenças , Cardiopatias/patologia , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/fisiopatologia , Mitocôndrias Cardíacas/metabolismo , Ratos
8.
J Pharmacol Sci ; 145(2): 187-197, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33451753

RESUMO

Roles of the renin-angiotensin system in autophagy and ischemia/reperfusion (I/R) injury in the kidney have not been fully characterized. Here we examined the hypothesis that modest activation of the angiotensin II (Ang II) receptor upregulates autophagy and increases renal tolerance to I/R injury. Sprague-Dawley rats were assigned to treatment with a vehicle or a non-pressor dose of Ang II (200 ng/kg/min) for 72 h before 30-min renal I/R. LC3-immunohistochemistry showed that Ang II treatment increased autophagosomes in proximal tubular cells by 2.7 fold. In Ang II-pretreated rats, autophagosomes were increased by 2.5 fold compared to those in vehicle-treated rats at 4 h after I/R, when phosphorylation of Akt and S6 was suppressed and ULK1-Ser555 phosphorylation was increased. Serum creatinine and urea nitrogen levels, incidence of oliguria, and histological score of tubular necrosis at 24 h after I/R were attenuated by Ang II-pretreatment. In NRK-52E cells, Ang II induced LC3-II upregulation, which was inhibited by losartan but not by A779. The results indicate that a non-pressor dose of Ang-II promotes autophagy via ULK1-mediated signaling in renal tubular cells and attenuates renal I/R injury. The AT1 receptor, but not the Mas receptor, contributes to Ang-II-induced autophagy and presumably also to the renoprotection.


Assuntos
Angiotensina II/administração & dosagem , Angiotensina II/farmacologia , Autofagia/efeitos dos fármacos , Túbulos Renais Proximais/citologia , Receptores de Angiotensina/metabolismo , Receptores de Angiotensina/fisiologia , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/prevenção & controle , Animais , Autofagia/genética , Células Cultivadas , Masculino , Ratos Sprague-Dawley , Sistema Renina-Angiotensina/fisiologia , Traumatismo por Reperfusão/etiologia
9.
Clin Exp Nephrol ; 25(12): 1360-1366, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34251521

RESUMO

BACKGROUND: Serum vitamin D level shows a seasonal variation, being lower in winter than in summer in healthy subjects. The aim of this study was to determine whether there is presence of such a seasonal variation in hemodialysis patients. METHODS: A total of 102 patients on hemodialysis were enrolled in February 2017 (winter) for analyses of serum levels of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)2D] and treatments for chronic kidney disease-mineral and bone disorder (CKD-MBD). The examinations were repeated in August 2017 (summer). After exclusion of patients with malignancy, loss of follow-up and missing data, 78 patients contributed to the analyses. RESULTS: Serum level of 25(OH)D, but not that of 1,25(OH)2D, was significantly lower in winter (14.0 ng/mL) than in summer (15.5 ng/mL), though there was no significant difference in regimen for CKD-MBD treatment including vitamin D receptor activators (VDRAs) between the two seasons. Serum intact parathyroid hormone level tended to be higher and alkaline phosphatase was significantly higher in winter than in summer. Linear mixed-effects model analysis showed that level of 25(OH)D, but not that of 1,25(OH)2D, was significantly associated with season (winter and summer) after adjustment of age, sex, dialysis vintage, albumin level and use of drugs for CKD-MBD. CONCLUSION: Serum 25(OH)D has a seasonal variation, being lower in winter than in summer, independent of CKD-MBD treatment including treatment with VDRAs in Japanese hemodialysis patients. The impact of the seasonal variation on risk of vitamin D deficiency and its effect on prognosis remain to be investigated.


Assuntos
Nefropatias/terapia , Diálise Renal , Estações do Ano , Deficiência de Vitamina D/sangue , Vitamina D/análogos & derivados , Idoso , Biomarcadores/sangue , Feminino , Humanos , Japão , Nefropatias/sangue , Nefropatias/diagnóstico , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Vitamina D/sangue , Deficiência de Vitamina D/diagnóstico
10.
Clin Exp Nephrol ; 25(3): 297-304, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33206249

RESUMO

BACKGROUND: Atrial fibrillation (AF) is an established risk factor for ischemic stroke in a general population. However, its impact in patients on hemodialysis (HD), a group with a high risk for stroke, is still controversial. Here we examined this issue in a Japanese cohort. METHODS: This study was designed as a multicenter cohort study. HD patients (n = 1,067) were enrolled from 22 institutes in January 2009 and followed up for 3 years. Patients with missing data (n = 196) or kidney transplantation (n = 4) were excluded, and 867 patients contributed to the analysis of the risk of new-onset of ischemic stroke. RESULTS: At baseline, AF was observed in 123 patients (14.2%, AF group) and not in the others (n = 744: 85.8%, non-AF group). During a follow-up period of 31.3 months, the cumulative incidence rate for ischemic stroke was significantly higher in the AF group than in the non-AF group (6.5% vs. 2.9%, p < 0.05). In Cox regression analysis, AF was a significant independent risk factor for new-onset of ischemic stroke after adjustment for age, sex, prior history of ischemic stroke, use of warfarin, dialysis vintage, comorbidity of diabetic nephropathy, and interdialytic weight gain (hazard ratio 2.17-2.68). CONCLUSION: Present analyses using comprehensive adjustment for multiple confounders, including prior history of ischemic stroke, indicated that AF independently increases the risk of new-onset of ischemic stroke by more than twofold in Japanese HD patients.


Assuntos
Fibrilação Atrial/epidemiologia , AVC Isquêmico/epidemiologia , Nefropatias/terapia , Diálise Renal/efeitos adversos , Idoso , Fibrilação Atrial/diagnóstico , Feminino , Humanos , Incidência , AVC Isquêmico/diagnóstico , Japão/epidemiologia , Nefropatias/diagnóstico , Nefropatias/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
11.
Endocr J ; 68(12): 1391-1402, 2021 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-34234055

RESUMO

Levels of alanine aminotransferase (ALT) and γ-glutamyl transferase (GGT) have been reported to be associated with increased risk of diabetes mellitus (DM). However, whether a combination of levels of ALT and GGT predicts new onset of DM better than does ALT or GGT alone in both males and females has not fully been addressed. We investigated the relationship between the combination of ALT and GGT and DM development during a 10-year follow-up period in 13,919 subjects (male/female: 8,983/4,936; age 48 ± 10 years) who received health examinations. During the 10-year period, 617 males (6.9%) and 153 females (3.1%) had new onset of DM. Multivariable Cox proportional hazard models with a restricted cubic spline showed that hazard ratios (HRs) of DM development increased with higher levels of ALT and GGT at baseline in both sexes after adjustment of confounding factors. When divided into 4 subgroups of high (H-) and low (L-) levels of ALT (male/female: 27/21 U/L) and GGT (male/female: 43/23 U/L) using cutoff values shown by receiver operating characteristic curve analyses, the adjusted HR in the H-ALT/H-GGT group was significantly higher than HR in the L-ALT/L-GGT group as the reference in males (HR [95% confidence interval]: 1.73[1.36-2.20], p < 0.001) but was not significantly higher in females (1.50 [0.97-2.33], p = 0.065). The addition of the combination of H-ALT/H-GGT to traditional risk factors with and without H-ALT or H-GGT alone significantly improved the discriminatory capability for predicting development of DM. In conclusion, the combination of H-ALT/H-GGT efficiently predicts development of DM in male individuals but not significantly in female individuals.


Assuntos
Diabetes Mellitus , gama-Glutamiltransferase , Adulto , Alanina Transaminase , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
14.
Cureus ; 16(8): e66834, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39280451

RESUMO

Beer potomania is a condition characterized by severe hyponatremia in chronic alcoholics with poor nutritional intake. When complicated by acute kidney injury (AKI), it presents a significant management challenge. We report a case of a 32-year-old male with a history of alcoholism who presented with malaise, nausea, and vomiting. Laboratory tests revealed severe hyponatremia (serum sodium 104 mEq/L) and AKI. Conventional treatment approaches posed risks of overcorrection and osmotic demyelination syndrome (ODS). We implemented continuous kidney replacement therapy (CKRT) with meticulously adjusted dialysate sodium concentrations. This approach enabled gradual, controlled correction of serum sodium without precipitating ODS. The patient was successfully liberated from hemodialysis on the twelfth day of illness. Our findings highlight the potential of CKRT as an effective treatment modality for severe hyponatremia in beer potomania with AKI, offering a means of gradual sodium correction while addressing renal dysfunction. This case underscores the importance of tailored management strategies in complex clinical scenarios involving electrolyte imbalances and kidney injury.

15.
J Diabetes Investig ; 14(4): 560-569, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36815317

RESUMO

AIMS/INTRODUCTION: We previously showed that upregulation of myocardial adenosine monophosphate deaminase (AMPD) is associated with pressure overload-induced diastolic dysfunction in type 2 diabetes hearts. Here, we examined involvement of AMPD localized in the endoplasmic reticulum-mitochondria interface in mitochondrial Ca2+ overload and its pathological significance. MATERIALS AND METHODS: We used type 2 diabetes Otsuka Long-Evans Tokushima Fatty rats (OLETF) and non-diabetes Long-Evans Tokushima Otsuka Fatty rats (LETO) as well as AMPD3-overexpressing H9c2 cells and human embryonic kidney 293 cells. RESULTS: OLETF, but not LETO, showed diastolic dysfunction under the condition of phenylephrine-induced pressure overload. The levels of 90-kDa AMPD3 in outer mitochondrial membranes/endoplasmic reticulum and mitochondria-associated endoplasmic reticulum membrane (MAM) fractions were significantly higher in OLETF than in LETO. The area of the MAM quantified by electron microscopic analysis was 57% larger, mitochondrial Ca2+ level under the condition of pressure overload was 47% higher and Ca2+ retention capacity in MAM-containing crude mitochondria isolated before the pressure overloading was 21% lower in OLETF than in LETO (all P-values <0.05). Transfection of FLAG-AMPD3 in cells resulted in significant enlargement of the MAM area, and impairment in pyruvate/malate-driven adenosine triphosphate-stimulated and uncoupler-stimulated mitochondrial respiration compared with those in control cells. CONCLUSIONS: The findings suggest that 90-kDa AMPD3 localized in the endoplasmic reticulum-mitochondria interface promotes formation of the MAM, inducing mitochondrial Ca2+ overload and dysfunction in type 2 diabetes hearts.


Assuntos
Diabetes Mellitus Tipo 2 , Ratos , Animais , Humanos , Diabetes Mellitus Tipo 2/patologia , Ratos Endogâmicos OLETF , Ratos Long-Evans , Mitocôndrias/patologia , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/patologia , Monofosfato de Adenosina/metabolismo
16.
Physiol Rep ; 11(4): e15608, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36802195

RESUMO

Systemic branched-chain amino acid (BCAA) metabolism is dysregulated in cardiometabolic diseases. We previously demonstrated that upregulated AMP deaminase 3 (AMPD3) impairs cardiac energetics in a rat model of obese type 2 diabetes, Otsuka Long-Evans-Tokushima fatty (OLETF). Here, we hypothesized that the cardiac BCAA levels and the activity of branched-chain α-keto acid dehydrogenase (BCKDH), a rate-limiting enzyme in BCAA metabolism, are altered by type 2 diabetes (T2DM), and that upregulated AMPD3 expression is involved in the alteration. Performing proteomic analysis combined with immunoblotting, we discovered that BCKDH localizes not only to mitochondria but also to the endoplasmic reticulum (ER), where it interacts with AMPD3. Knocking down AMPD3 in neonatal rat cardiomyocytes (NRCMs) increased BCKDH activity, suggesting that AMPD3 negatively regulates BCKDH. Compared with control rats (Long-Evans Tokushima Otsuka [LETO] rats), OLETF rats exhibited 49% higher cardiac BCAA levels and 49% lower BCKDH activity. In the cardiac ER of the OLETF rats, BCKDH-E1α subunit expression was downregulated, while AMPD3 expression was upregulated, resulting in an 80% lower AMPD3-E1α interaction compared to LETO rats. Knocking down E1α expression in NRCMs upregulated AMPD3 expression and recapitulated the imbalanced AMPD3-BCKDH expressions observed in OLETF rat hearts. E1α knockdown in NRCMs inhibited glucose oxidation in response to insulin, palmitate oxidation, and lipid droplet biogenesis under oleate loading. Collectively, these data revealed previously unrecognized extramitochondrial localization of BCKDH in the heart and its reciprocal regulation with AMPD3 and imbalanced AMPD3-BCKDH interactions in OLETF. Downregulation of BCKDH in cardiomyocytes induced profound metabolic changes that are observed in OLETF hearts, providing insight into mechanisms contributing to the development of diabetic cardiomyopathy.


Assuntos
3-Metil-2-Oxobutanoato Desidrogenase (Lipoamida) , AMP Desaminase , Diabetes Mellitus Tipo 2 , Animais , Ratos , AMP Desaminase/genética , AMP Desaminase/metabolismo , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Regulação para Baixo , Proteômica , Ratos Endogâmicos OLETF , Ratos Long-Evans , 3-Metil-2-Oxobutanoato Desidrogenase (Lipoamida)/genética
17.
Clin Kidney J ; 15(10): 1888-1895, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36158142

RESUMO

Background: Relationships between levels of serum lipid fractions and the time course of renal function are discrepant in the literature. Here we examined this issue by analyses of healthy subjects in a cohort. Methods: Of all subjects who received health examinations at Keijinkai Maruyama Clinic, Sapporo in 2006, subjects with hypertension, diabetes mellitus or chronic kidney disease (CKD) and those taking medication for dyslipidemia were excluded and a total of 5586 subjects (male/female: 3563/2023, mean age: 43 ± 8 years) were followed for 10 years. Results: Linear mixed effect models showed that baseline low-density lipoprotein-cholesterol (LDL-C) level was negatively associated with estimated glomerular filtration rate (eGFR) during the 10-year follow-up period after adjustment for confounders. Interactions between the follow-up year and baseline level of LDL-C or high-density lipoprotein-cholesterol (HDL-C) for eGFR values during the follow-up period were significant in males but not in females. There were no significant interactions for eGFR between the follow-up year and baseline levels of total cholesterol, triglycerides, or HDL-C/triglycerides ratio. During the follow-up period, 346 males and 223 females developed CKD. When male subjects were divided into subgroups according to tertiles of baseline levels of LDL-C, the adjusted risk for CKD in the third tertial group was significantly higher than that in the first tertile group as a reference [hazard ratio (95% confidence interval): 1.39 (1.02-1.90), P = .035]. Such a difference was not observed for LDL-C tertiles in females or HDL-C tertiles in both sexes. Conclusions: A high LDL-C level may be a risk factor for new-onset CKD in apparently healthy males.

18.
Front Endocrinol (Lausanne) ; 13: 997296, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36157458

RESUMO

Type B insulin resistance syndrome (TBIR) is a rare disease characterized by refractory diabetes due to severe insulin resistance caused by anti-insulin receptor autoantibodies, and a standard treatment regimen for TBIR has not been established, leading to therapeutic difficulties and high mortality. Since TBIR is known to be associated with autoimmune diseases such as systemic lupus erythematosus (SLE), glucocorticoids are often used as key immunosuppressive agents. However, glucocorticoids have the potential to exacerbate the pathophysiology of TBIR by worsening insulin sensitivity, which leads to hyperglycemia and muscle wasting. Here, we report a case history of a 66-year-old man who was diagnosed as having TBIR in combination with SLE and Sjögren's syndrome with marked hyperglycemia, ketosis, and muscle wasting. He was successfully treated with combination therapy of double-filtration plasmapheresis (DFPP) and administration of the anti-CD20 monoclonal antibody rituximab without induction of glucocorticoid therapy while using a sensor-augmented insulin pump (SAP) to prevent hypoglycemia. Remission of diabetes was achieved without severe hypoglycemic events and his circulating insulin receptor antibodies became negative after seven months of initiation of these treatments. Based on the successful clinical courses of this case, our report suggests the possibility of an effective therapeutic regimen with DFPP and rituximab under the condition of the use of an SAP for a patient with TBIR without induction of glucocorticoids.


Assuntos
Doenças Autoimunes , Diabetes Mellitus , Hiperglicemia , Resistência à Insulina , Lúpus Eritematoso Sistêmico , Idoso , Anticorpos Monoclonais/uso terapêutico , Autoanticorpos , Diabetes Mellitus/tratamento farmacológico , Glucocorticoides/uso terapêutico , Humanos , Hiperglicemia/complicações , Hipoglicemiantes/uso terapêutico , Imunossupressores/uso terapêutico , Lúpus Eritematoso Sistêmico/complicações , Masculino , Plasmaferese , Rituximab/uso terapêutico
19.
Sci Rep ; 11(1): 8606, 2021 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-33883636

RESUMO

A potential link between chronic kidney disease (CKD) and non-alcoholic fatty liver disease (NAFLD) has been suggested. We investigated the relationship between fatty liver index (FLI), a noninvasive and simple predictor of NAFLD, and the development of CKD defined as estimated glomerular filtration rate < 60 mL/min/1.73 m2 or positive for urinary protein during a 10-year follow-up period in subjects who received annual health examinations (n = 28,890). After exclusion of CKD at baseline, a total of 14,163 subjects (male/female: 9077/5086) were recruited. During the 10-year period, 1458 males (16.1%) and 737 females (14.5%) had new onset of CKD. Multivariable Cox proportional hazard models with a restricted cubic spline showed that hazard ratios (HRs) of CKD development increased with a higher FLI at baseline in both males and females after adjustment of confounders. When divided by tertiles of FLI level at baseline (T1 ~ T3), the adjusted risk of CKD development in the T3 group (HR [95% confidence interval], male/female: 1.33 [1.16-1.54]/1.33 [1.08-1.63]) was significantly higher than that in both sexes in the T1 group as the reference. The addition of FLI into traditional risk factors significantly improved the discriminatory capability for predicting CKD. In conclusion, a high level of FLI predicts the development of CKD in both sexes in a general population.


Assuntos
Rim/patologia , Hepatopatia Gordurosa não Alcoólica/patologia , Insuficiência Renal Crônica/patologia , Feminino , Taxa de Filtração Glomerular/fisiologia , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Fatores de Risco
20.
Hypertens Res ; 44(1): 107-116, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32792577

RESUMO

While hyperuricemia is recognized as a risk factor for chronic kidney disease (CKD), the risk of CKD in subjects with a low level of serum uric acid (UA) remains controversial. Here, we examined whether the association of CKD risk with serum UA level differs depending on the sex and age of subjects in a general population. Of subjects who received annual health checkups, we enrolled 6,779 subjects (male/female: 4,454/2,325; age: 45 ± 9 years) with data from a 10-year follow-up after excluding subjects taking anti-hyperuricemic drugs and those with CKD at baseline. During the follow-up period, 11.4% of the males and 11.7% of the females developed CKD. A significant interaction of sex, but not age, with the effect of baseline UA level on CKD risk was found. A restricted cubic spline analysis showed a U-shaped association of the baseline UA level with the risk of CKD in females. Multivariable Cox proportional hazard analyses for females showed that baseline UA levels in the 5th quintile (Q5, ≥5 mg/dL; HR: 1.68) and the 1st quintile (Q1, ≤3.5 mg/dL; HR: 1.73) were independent risk factors for CKD when compared with UA levels in the 4th quintile (Q4, 4.5-4.9 mg/dL). In males, restricted cubic spline analysis indicated increased CKD risk in subjects with a higher baseline UA level but not in those with a low UA level. In conclusion, a low UA level is a significant risk factor for CKD in females, while an elevated UA level increases the risk of CKD in both sexes.


Assuntos
Taxa de Filtração Glomerular , Adulto , Feminino , Humanos , Hiperuricemia/epidemiologia , Rim/fisiologia , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/epidemiologia , Fatores de Risco , Ácido Úrico
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