RESUMEN
Glucagon like peptide-1 (GLP-1) is a hormone produced and released by cells of the gastrointestinal tract following meal ingestion. GLP-1 receptor agonists (GLP-1RA) exhibit kidney-protective actions through poorly understood mechanisms. Here we interrogated whether the receptor for advanced glycation end products (RAGE) plays a role in mediating the actions of GLP-1 on inflammation and diabetic kidney disease. Mice with deletion of the GLP-1 receptor displayed an abnormal kidney phenotype that was accelerated by diabetes and improved with co-deletion of RAGE in vivo. Activation of the GLP-1 receptor pathway with liraglutide, an anti-diabetic treatment, downregulated kidney RAGE, reduced the expansion of bone marrow myeloid progenitors, promoted M2-like macrophage polarization and lessened markers of kidney damage in diabetic mice. Single cell transcriptomics revealed that liraglutide induced distinct transcriptional changes in kidney endothelial, proximal tubular, podocyte and macrophage cells, which were dominated by pathways involved in nutrient transport and utilization, redox sensing and the resolution of inflammation. The kidney-protective action of liraglutide was corroborated in a non-diabetic model of chronic kidney disease, the subtotal nephrectomised rat. Thus, our findings identify a novel glucose-independent kidney-protective action of GLP-1-based therapies in diabetic kidney disease and provide a valuable resource for exploring the cell-specific kidney transcriptional response ensuing from pharmacological GLP-1R agonism.
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Diabetes Mellitus Experimental , Nefropatías Diabéticas , Ratas , Ratones , Animales , Receptor para Productos Finales de Glicación Avanzada/genética , Receptor para Productos Finales de Glicación Avanzada/metabolismo , Nefropatías Diabéticas/etiología , Nefropatías Diabéticas/genética , Liraglutida/farmacología , Liraglutida/uso terapéutico , Receptor del Péptido 1 Similar al Glucagón/genética , Diabetes Mellitus Experimental/metabolismo , Péptido 1 Similar al Glucagón/metabolismo , Péptido 1 Similar al Glucagón/farmacología , Péptido 1 Similar al Glucagón/uso terapéutico , InflamaciónRESUMEN
Gut microbiome research has increased dramatically in the last decade, including in renal health and disease. The field is moving from experiments showing mere association to causation using both forward and reverse microbiome approaches, leveraging tools such as germ-free animals, treatment with antibiotics, and fecal microbiota transplantations. However, we are still seeing a gap between discovery and translation that needs to be addressed, so that patients can benefit from microbiome-based therapies. In this guideline paper, we discuss the key considerations that affect the gut microbiome of animals and clinical studies assessing renal function, many of which are often overlooked, resulting in false-positive results. For animal studies, these include suppliers, acclimatization, baseline microbiota and its normalization, littermates and cohort/cage effects, diet, sex differences, age, circadian differences, antibiotics and sweeteners, and models used. Clinical studies have some unique considerations, which include sampling, gut transit time, dietary records, medication, and renal phenotypes. We provide best-practice guidance on sampling, storage, DNA extraction, and methods for microbial DNA sequencing (both 16S rRNA and shotgun metagenome). Finally, we discuss follow-up analyses, including tools available, metrics, and their interpretation, and the key challenges ahead in the microbiome field. By standardizing study designs, methods, and reporting, we will accelerate the findings from discovery to translation and result in new microbiome-based therapies that may improve renal health.
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Microbioma Gastrointestinal , Microbiota , Animales , Masculino , Femenino , ARN Ribosómico 16S/genética , Trasplante de Microbiota Fecal , AntibacterianosRESUMEN
Diabetic kidney disease (DKD) affects 30-40% of patients with diabetes and is currently the leading cause of end-stage renal disease (ESRD). The activation of the complement cascade, a highly conserved element of the innate immune system, has been implicated in the pathogenesis of diabetes and its complications. The potent anaphylatoxin C5a is a critical effector of complement-mediated inflammation. Excessive activation of the C5a-signalling axis promotes a potent inflammatory environment and is associated with mitochondrial dysfunction, inflammasome activation, and the production of reactive oxygen species. Conventional renoprotective agents used in the treatment of diabetes do not target the complement system. Mounting preclinical evidence indicates that inhibition of the complement system may prove protective in DKD by reducing inflammation and fibrosis. Targeting the C5a-receptor signaling axis is of particular interest, as inhibition at this level attenuates inflammation while preserving the critical immunological defense functions of the complement system. In this review, the important role of the C5a/C5a-receptor axis in the pathogenesis of diabetes and kidney injuries will be discussed, and an overview of the status and mechanisms of action of current complement therapeutics in development will be provided.
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Diabetes Mellitus , Nefropatías Diabéticas , Humanos , Nefropatías Diabéticas/tratamiento farmacológico , Nefropatías Diabéticas/etiología , Complemento C5a , Proteínas del Sistema Complemento , Riñón , Inflamación/tratamiento farmacológico , Receptor de Anafilatoxina C5a , Activación de ComplementoRESUMEN
A recently published study by Bell et al. shows altered immunotolerance in people with type 1 diabetes by dietary supplementation of modified resistant starch fibre.
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Diabetes Mellitus , Almidón , Diabetes Mellitus/terapia , Fibras de la Dieta , HumanosRESUMEN
Diabetic kidney disease is expected to increase rapidly over the coming decades with rising prevalence of diabetes worldwide. Current measures of kidney function based on albuminuria and estimated glomerular filtration rate do not accurately stratify and predict individuals at risk of declining kidney function in diabetes. As a result, recent attention has turned towards identifying and assessing the utility of biomarkers in diabetic kidney disease. This review explores the current literature on biomarkers of inflammation and kidney injury focussing on studies of single or multiple biomarkers between January 2014 and February 2020. Multiple serum and urine biomarkers of inflammation and kidney injury have demonstrated significant association with the development and progression of diabetic kidney disease. Of the inflammatory biomarkers, tumour necrosis factor receptor-1 and -2 were frequently studied and appear to hold most promise as markers of diabetic kidney disease. With regards to kidney injury biomarkers, studies have largely targeted markers of tubular injury of which kidney injury molecule-1, beta-2-microglobulin and neutrophil gelatinase-associated lipocalin emerged as potential candidates. Finally, the use of a small panel of selective biomarkers appears to perform just as well as a panel of multiple biomarkers for predicting kidney function decline.
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Diabetes Mellitus , Nefropatías Diabéticas , Albuminuria/diagnóstico , Albuminuria/etiología , Biomarcadores , Diabetes Mellitus/patología , Nefropatías Diabéticas/diagnóstico , Nefropatías Diabéticas/etiología , Nefropatías Diabéticas/patología , Tasa de Filtración Glomerular , Receptor Celular 1 del Virus de la Hepatitis A/metabolismo , Humanos , Inflamación/complicaciones , Inflamación/patología , Riñón/patología , Lipocalina 2RESUMEN
There is increasing evidence for the role of intestinal permeability as a contributing factor in the pathogenesis of diabetes; however, the molecular mechanisms are poorly understood. Advanced glycation endproducts, of both exogenous and endogenous origin, have been shown to play a role in diabetes pathophysiology, in part by their ligation to the receptor for advanced glycation endproducts (RAGE), leading to a proinflammatory signalling cascade. RAGE signalling has been demonstrated to play a role in the development of intestinal inflammation and permeability in Crohn's disease and ulcerative colitis. In this review, we explore the role of AGE-RAGE signalling and intestinal permeability and explore whether activation of RAGE on the intestinal epithelium may be a downstream event contributing to the pathogenesis of diabetes complications.
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Diabetes Mellitus/fisiopatología , Productos Finales de Glicación Avanzada/metabolismo , Intestinos/fisiopatología , Receptor para Productos Finales de Glicación Avanzada/metabolismo , Transducción de Señal , Animales , Humanos , PermeabilidadRESUMEN
BACKGROUND: High blood pressure (BP) continues to be a major, poorly controlled but modifiable risk factor for cardiovascular death. Among key Western lifestyle factors, a diet poor in fiber is associated with prevalence of high BP. The impact of lack of prebiotic fiber and the associated mechanisms that lead to higher BP are unknown. Here we show that lack of prebiotic dietary fiber leads to the development of a hypertensinogenic gut microbiota, hypertension and its complications, and demonstrate a role for G-protein coupled-receptors (GPCRs) that sense gut metabolites. METHODS: One hundred seventy-nine mice including C57BL/6J, gnotobiotic C57BL/6J, and knockout strains for GPR41, GPR43, GPR109A, and GPR43/109A were included. C57BL/6J mice were implanted with minipumps containing saline or a slow-pressor dose of angiotensin II (0.25 mg·kg-1·d-1). Mice were fed diets lacking prebiotic fiber with or without addition of gut metabolites called short-chain fatty acids ([SCFA)] produced during fermentation of prebiotic fiber in the large intestine), or high prebiotic fiber diets. Cardiac histology and function, BP, sodium and potassium excretion, gut microbiome, flow cytometry, catecholamines and methylation-wide changes were determined. RESULTS: Lack of prebiotic fiber predisposed mice to hypertension in the presence of a mild hypertensive stimulus, with resultant pathological cardiac remodeling. Transfer of a hypertensinogenic microbiota to gnotobiotic mice recapitulated the prebiotic-deprived hypertensive phenotype, including cardiac manifestations. Reintroduction of SCFAs to fiber-depleted mice had protective effects on the development of hypertension, cardiac hypertrophy, and fibrosis. The cardioprotective effect of SCFAs were mediated via the cognate SCFA receptors GPR43/GPR109A, and modulated L-3,4-dihydroxyphenylalanine levels and the abundance of T regulatory cells regulated by DNA methylation. CONCLUSIONS: The detrimental effects of low fiber Westernized diets may underlie hypertension, through deficient SCFA production and GPR43/109A signaling. Maintaining a healthy, SCFA-producing microbiota is important for cardiovascular health.
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Fibras de la Dieta/deficiencia , Ácidos Grasos Volátiles/metabolismo , Microbioma Gastrointestinal , Hipertensión , Mucosa Intestinal , Prebióticos , Receptores Acoplados a Proteínas G/metabolismo , Transducción de Señal , Animales , Hipertensión/genética , Hipertensión/metabolismo , Hipertensión/microbiología , Hipertensión/patología , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiología , Mucosa Intestinal/patología , Masculino , Ratones , Ratones Noqueados , Receptores Acoplados a Proteínas G/genéticaRESUMEN
Type 2 diabetes (T2D) manifests from inadequate glucose control due to insulin resistance, hypoinsulinemia, and deteriorating pancreatic ß-cell function. The pro-inflammatory factor Activin has been implicated as a positive correlate of severity in T2D patients, and as a negative regulator of glucose uptake by skeletal muscle, and of pancreatic ß-cell phenotype in mice. Accordingly, we sought to determine whether intervention with the Activin antagonist Follistatin can ameliorate the diabetic pathology. Here, we report that an intravenous Follistatin gene delivery intervention with tropism for striated muscle reduced the serum concentrations of Activin B and improved glycemic control in the db/db mouse model of T2D. Treatment reversed the hyperglycemic progression with a corresponding reduction in the percentage of glycated-hemoglobin to levels similar to lean, healthy mice. Follistatin gene delivery promoted insulinemia and abundance of insulin-positive pancreatic ß-cells, even when treatment was administered to mice with advanced diabetes, supporting a mechanism for improved glycemic control associated with maintenance of functional ß-cells. Our data demonstrate that single-dose intravascular Follistatin gene delivery can ameliorate the diabetic progression and improve prognostic markers of disease. These findings are consistent with other observations of Activin-mediated mechanisms exerting deleterious effects in models of obesity and diabetes, and suggest that interventions that attenuate Activin signaling could help further understanding of T2D and the development of novel T2D therapeutics.
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Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 2/terapia , Folistatina/genética , Técnicas de Transferencia de Gen , Terapia Genética , Control Glucémico , Hiperglucemia/terapia , Administración Intravenosa , Animales , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patología , Folistatina/administración & dosificación , Hiperglucemia/genética , Resistencia a la Insulina , RatonesRESUMEN
BACKGROUND: The nicotinamide adenine dinucleotide phosphate oxidase isoform 4 (Nox4) mediates reactive oxygen species (ROS) production and renal fibrosis in diabetic kidney disease (DKD) at the level of the podocyte. However, the mitochondrial localization of Nox4 and its role as a mitochondrial bioenergetic sensor has recently been reported. Whether Nox4 drives pathology in DKD within the proximal tubular compartment, which is densely packed with mitochondria, is not yet known. METHODS: We generated a proximal tubular-specific Nox4 knockout mouse model by breeding Nox4flox/flox mice with mice expressing Cre recombinase under the control of the sodium-glucose cotransporter-2 promoter. Subsets of Nox4ptKO mice and their Nox4flox/flox littermates were injected with streptozotocin (STZ) to induce diabetes. Mice were followed for 20 weeks and renal injury was assessed. RESULTS: Genetic ablation of proximal tubular Nox4 (Nox4ptKO) resulted in no change in renal function and histology. Nox4ptKO mice and Nox4flox/flox littermates injected with STZ exhibited the hallmarks of DKD, including hyperfiltration, albuminuria, renal fibrosis and glomerulosclerosis. Surprisingly, diabetes-induced renal injury was not improved in Nox4ptKO STZ mice compared with Nox4flox/flox STZ mice. Although diabetes conferred ROS overproduction and increased the mitochondrial oxygen consumption rate, proximal tubular deletion of Nox4 did not normalize oxidative stress or mitochondrial bioenergetics. CONCLUSIONS: Taken together, these results demonstrate that genetic deletion of Nox4 from the proximal tubules does not influence DKD development, indicating that Nox4 localization within this highly energetic compartment is dispensable for chronic kidney disease pathogenesis in the setting of diabetes.
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Diabetes Mellitus Experimental , Nefropatías Diabéticas , Animales , Nefropatías Diabéticas/genética , Riñón , Túbulos Renales , Túbulos Renales Proximales , Ratones , NADP , NADPH Oxidasa 4/genética , NADPH Oxidasas/genética , Especies Reactivas de OxígenoRESUMEN
Alterations in gut homeostasis may contribute to the progression of diabetic nephropathy. There has been recent attention on the renoprotective effects of metabolite-sensing receptors in chronic renal injury, including the G protein-coupled receptor (GPR)109a, which ligates the short-chain fatty acid butyrate. However, the role of GPR109a in the development of diabetic nephropathy, a milieu of diminished microbiome-derived metabolites, has not yet been determined. The present study aimed to assess the effects of insufficient GPR109a signaling, via genetic deletion of GPR109a, on the development of renal injury in diabetic nephropathy. Gpr109a-/- mice or their wild-type littermates (Gpr109a+/+) were rendered diabetic with streptozotocin. Mice received a control diet or an isocaloric high-fiber diet (12.5% resistant starch) for 24 wk, and gastrointestinal permeability and renal injury were determined. Diabetes was associated with increased albuminuria, glomerulosclerosis, and inflammation. In comparison, Gpr109a-/- mice with diabetes did not show an altered renal phenotype. Resistant starch supplementation did not afford protection from renal injury in diabetic nephropathy. While diabetes was associated with alterations in intestinal morphology, intestinal permeability assessed in vivo using the FITC-dextran test was unaltered. GPR109a deletion did not worsen gastrointestinal permeability. Furthermore, 12.5% resistant starch supplementation, at physiological concentrations, had no effect on intestinal permeability or morphology. The results of this study indicate that GPR109a does not play a critical role in intestinal homeostasis in a model of type 1 diabetes or in the development of diabetic nephropathy.
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Nefropatías Diabéticas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animales , Peso Corporal , Diabetes Mellitus Experimental , Hemoglobina Glucada , Intestinos/anatomía & histología , Intestinos/fisiología , Masculino , Ratones , Ratones Noqueados , Permeabilidad , Receptores Acoplados a Proteínas G/genéticaRESUMEN
Mitochondrial stress has been widely observed in diabetic kidney disease (DKD). Cyclophilin D (CypD) is a functional component of the mitochondrial permeability transition pore (mPTP) which allows the exchange of ions and solutes between the mitochondrial matrix to induce mitochondrial swelling and activation of cell death pathways. CypD has been successfully targeted in other disease contexts to improve mitochondrial function and reduced pathology. Two approaches were used to elucidate the role of CypD and the mPTP in DKD. Firstly, mice with a deletion of the gene encoding CypD (Ppif-/-) were rendered diabetic with streptozotocin (STZ) and followed for 24 weeks. Secondly, Alisporivir, a CypD inhibitor was administered to the db/db mouse model (5 mg/kg/day oral gavage for 16 weeks). Ppif-/- mice were not protected against diabetes-induced albuminuria and had greater glomerulosclerosis than their WT diabetic littermates. Renal hyperfiltration was lower in diabetic Ppif-/- as compared with WT mice. Similarly, Alisporivir did not improve renal function nor pathology in db/db mice as assessed by no change in albuminuria, KIM-1 excretion and glomerulosclerosis. Db/db mice exhibited changes in mitochondrial function, including elevated respiratory control ratio (RCR), reduced mitochondrial H2O2 generation and increased proximal tubular mitochondrial volume, but these were unaffected by Alisporivir treatment. Taken together, these studies indicate that CypD has a complex role in DKD and direct targeting of this component of the mPTP will likely not improve renal outcomes.
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Diabetes Mellitus Experimental/metabolismo , Enfermedades Renales/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Peptidil-Prolil Isomerasa F/metabolismo , Albuminuria/genética , Albuminuria/metabolismo , Animales , Peptidil-Prolil Isomerasa F/antagonistas & inhibidores , Peptidil-Prolil Isomerasa F/genética , Ciclosporina/farmacología , Diabetes Mellitus Experimental/genética , Nefropatías Diabéticas/genética , Nefropatías Diabéticas/metabolismo , Peróxido de Hidrógeno/metabolismo , Riñón/efectos de los fármacos , Riñón/metabolismo , Riñón/patología , Enfermedades Renales/genética , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/genética , Poro de Transición de la Permeabilidad Mitocondrial , ATPasas de Translocación de Protón/metabolismoRESUMEN
The article "The Mitochondria-Targeted Methylglyoxal Sequestering Compound, MitoGamide, Is Cardioprotective in the Diabetic Heart".
RESUMEN
PURPOSE: HFpEF (heart failure with preserved ejection fraction) is a major consequence of diabetic cardiomyopathy with no effective treatments. Here, we have characterized Akita mice as a preclinical model of HFpEF and used it to confirm the therapeutic efficacy of the mitochondria-targeted dicarbonyl scavenger, MitoGamide. METHODS AND RESULTS: A longitudinal echocardiographic analysis confirmed that Akita mice develop diastolic dysfunction with reduced E peak velocity, E/A ratio and extended isovolumetric relaxation time (IVRT), while the systolic function remains comparable with wild-type mice. The myocardium of Akita mice had a decreased ATP/ADP ratio, elevated mitochondrial oxidative stress and increased organelle density, compared with that of wild-type mice. MitoGamide, a mitochondria-targeted 1,2-dicarbonyl scavenger, exhibited good stability in vivo, uptake into cells and mitochondria and reactivity with dicarbonyls. Treatment of Akita mice with MitoGamide for 12 weeks significantly improved the E/A ratio compared with the vehicle-treated group. CONCLUSION: Our work confirms that the Akita mouse model of diabetes replicates key clinical features of diabetic HFpEF, including cardiac and mitochondrial dysfunction. Furthermore, in this independent study, MitoGamide treatment improved diastolic function in Akita mice.
Asunto(s)
Benzamidas/farmacología , Fármacos Cardiovasculares/farmacología , Cardiomiopatías Diabéticas/prevención & control , Insuficiencia Cardíaca/prevención & control , Volumen Sistólico/efectos de los fármacos , Disfunción Ventricular Izquierda/prevención & control , Función Ventricular Izquierda/efectos de los fármacos , Animales , Cardiomiopatías Diabéticas/metabolismo , Cardiomiopatías Diabéticas/fisiopatología , Modelos Animales de Enfermedad , Productos Finales de Glicación Avanzada/metabolismo , Insuficiencia Cardíaca/metabolismo , Insuficiencia Cardíaca/fisiopatología , Masculino , Ratones Endogámicos C57BL , Ratones Mutantes , Mitocondrias Cardíacas/efectos de los fármacos , Mitocondrias Cardíacas/metabolismo , Disfunción Ventricular Izquierda/metabolismo , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
PURPOSE: Methylglyoxal, a by-product of glycolysis and a precursor in the formation of advanced glycation end-products, is significantly elevated in the diabetic myocardium. Therefore, we sought to investigate the mitochondria-targeted methylglyoxal scavenger, MitoGamide, in an experimental model of spontaneous diabetic cardiomyopathy. METHODS: Male 6-week-old Akita or wild type mice received daily oral gavage of MitoGamide or vehicle for 10 weeks. Several morphological and systemic parameters were assessed, as well as cardiac function by echocardiography. RESULTS: Akita mice were smaller in size than wild type counterparts in terms of body weight and tibial length. Akita mice exhibited elevated blood glucose and glycated haemoglobin. Total heart and individual ventricles were all smaller in Akita mice. None of the aforementioned parameters was impacted by MitoGamide treatment. Echocardiographic analysis confirmed that cardiac dimensions were smaller in Akita hearts. Diastolic dysfunction was evident in Akita mice, and notably, MitoGamide treatment preferentially improved several of these markers, including e'/a' ratio and E/e' ratio. CONCLUSIONS: Our findings suggest that MitoGamide, a novel mitochondria-targeted approach, offers cardioprotection in experimental diabetes and therefore may offer therapeutic potential for the treatment of cardiomyopathy in patients with diabetes.
Asunto(s)
Amidas/farmacología , Benzamidas/farmacología , Cardiotónicos/farmacología , Cardiomiopatías Diabéticas/tratamiento farmacológico , Difenilamina/farmacología , Mitocondrias Cardíacas/efectos de los fármacos , Piruvaldehído/metabolismo , Función Ventricular Izquierda/efectos de los fármacos , Animales , Benzamidas/uso terapéutico , Cardiomiopatías Diabéticas/genética , Cardiomiopatías Diabéticas/metabolismo , Cardiomiopatías Diabéticas/fisiopatología , Modelos Animales de Enfermedad , Insulina/genética , Masculino , Ratones Endogámicos C57BL , Mitocondrias Cardíacas/metabolismo , MutaciónRESUMEN
STUDY QUESTION: Do obese levels of advanced glycation end products (AGEs) within the uterine cavity detrimentally alter tissue function in embryo implantation and placental development? SUMMARY ANSWER: Obese levels of AGEs activate inflammatory signaling (p65 NFκB) within endometrial epithelial cells and alter their function, cause endoplasmic reticulum (ER) stress in endometrial stromal cells and impair decidualization, compromise implantation of blastocyst mimics and inhibit trophoblast invasion. WHAT IS KNOWN ALREADY: Obese women experience a higher incidence of infertility, recurrent miscarriage and pregnancy complications compared with lean women. Oocyte donation cycles suggest a detrimental uterine environment plays a role in these outcomes. STUDY DESIGN, SIZE, DURATION: Uterine lavage and tissues from lean (BMI 19.5-24.9, n = 17) and obese (BMI > 30, n = 16) women examined. Cell culture experiments utilizing human endometrial epithelial, trophectoderm and trophoblast cell lines and primary human stromal cells used to examine the functional impact of obese levels of AGEs. PARTICIPANTS/MATERIALS, SETTING, METHODS: Levels of AGEs examined within uterine lavage assessed by ELISA to determine differences between lean and obese women. Expression and localization of AGEs, receptor for AGEs (RAGE) and NFκB within endometrial tissues obtained from lean and obese women determined by immunohistochemistry. Endometrial epithelial cells (ECC-1), primary human stromal cells and trophoblast cells (HTR8-SVneo) treated with lean (2000 nmol/mol lysine) or obese (8000 nmol/mol lysine) uterine levels of AGEs and p65 NFκB (western immunoblot), real-time adhesion, proliferation migration and invasion (xCelligence real-time cell function analysis), decidualization (cell morphology and prolactin release), ER stress (western immunoblot for p-PERK) determined. Co-cultures of endometrial epithelial cells and blastocyst mimics (trophectoderm spheroids) similarly treated with lean or obese uterine levels of AGEs to determine their impact on embryo implantation. MAIN RESULTS AND THE ROLE OF CHANCE: AGEs were significantly elevated (P = 0.004) within the obese (6503.59 µmol/mol lysine) versus lean (2165.88 µmol/mol lysine) uterine cavity (uterine lavage) with increased immunostaining for AGEs, RAGE and NFkB within obese endometrial tissues during the proliferative phase of the menstrual cycle. Obese uterine levels of AGEs inhibited adhesion and proliferation of endometrial epithelial (ECC-1) cells compared to treatment with lean uterine levels of AGEs. Obese uterine AGE levels impacted primary human endometrial stromal cell decidualization and activated ER stress within these cells. Obese uterine levels of AGEs also inhibited trophectodermal spheroid adhesion to hormonally primed endometrial epithelial cells and trophoblast cell line HTR8/SV-neo invasion. LARGE SCALE DATA: N/A. LIMITATIONS REASONS FOR CAUTION: Mechanistic studies are performed in vitro and may not completely recapitulate cell function in vivo. WIDER IMPLICATIONS OF THE FINDINGS: These data corroborate clinical data suggesting the presence of an altered uterine environment in obese women and demonstrate that elevated uterine levels of AGEs within these women may detrimentally impact endometrial function, embryo implantation and placental development. Uterine AGE assessment in infertility work up may prove useful in determining underlying causes of infertility. AGEs can be targeted pharmacologically and such treatments may prove effective in improving reproductive complications experience by obese women. STUDY FUNDING/COMPETING INTEREST(S): Supported by NHMRC Fellowship (#1002028 to L.A.S.), and the Victorian Government's Operational Infrastructure Support Program. MTC is supported by a JDRF Australia Clinical Research Network Career Development Award. The authors have declared that no conflict of interest exists.
Asunto(s)
Implantación del Embrión/fisiología , Endometrio/metabolismo , Productos Finales de Glicación Avanzada/metabolismo , Obesidad/metabolismo , Útero/metabolismo , Adulto , Células Epiteliales/metabolismo , Femenino , Humanos , Placentación/fisiología , Embarazo , Células del Estroma/metabolismo , Trofoblastos/metabolismoRESUMEN
PURPOSE: Advanced glycation endproducts (AGEs) are produced endogenously and also enter the body during the consumption of AGEs present in heat-processed food. It is unknown whether AGEs of dietary origin accumulate within the body of healthy individuals. AGEs can deposit within skin tissue long-term by crosslinking extracellular matrix proteins. The fluorescent nature of many AGEs enables their detection within the skin by non-invasively measuring skin autofluorescence (SAF). This study aimed to identify habitual dietary and lifestyle behaviours cross-sectionally associated with SAF in an adult population sample. METHODS: 251 Healthy adult volunteers completed validated food frequency and physical activity questionnaires. Waist circumference, BMI, blood pressure and blood glucose was also measured. SAF was measured using an AGE Reader. RESULTS: Significant positive correlations were found between SAF and chronological age (r = 0.63, P < 0.001), waist circumference (r = 0.28, P < 0.01), body weight (r = 0.24, P < 0.05), BMI (r = 0.23, P < 0.05) and consumption of meat and meat products (r = 0.22, P < 0.05). A negative correlation was found between SAF and cereal consumption (r = -0.21, P < 0.05). Cigarette smokers also had a significantly higher SAF than non-smokers (2.4 vs 2.0 U, P < 0.05). Regression analysis identified age, cigarette smoking, waist circumference and intake of meat products as significant predictors of SAF. The regression model explained 48% of the variation in SAF. CONCLUSIONS: Age, cigarette smoking, waist circumference and dietary consumption of meat/meat products were positively associated with SAF in this sample. Further research is required to determine whether frequent consumption of foods containing large quantities of dietary AGEs contribute to pathological disease processes in healthy individuals.
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Dieta , Productos Finales de Glicación Avanzada/metabolismo , Estilo de Vida , Carne/efectos adversos , Piel/metabolismo , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Femenino , Productos Finales de Glicación Avanzada/análisis , Humanos , Masculino , Productos de la Carne/efectos adversos , Persona de Mediana Edad , Estudios Prospectivos , Fumar/efectos adversos , Adulto JovenRESUMEN
The role of autophagy in the kidney and many nephrological diseases has gained prominence in recent years. Much of this research has been focused on markers of autophagy that are static and reveal little about the state of this dynamic pathway. Other mechanistic investigations are limited to in vitro studies, that often provide circumstantial evidence of autophagic flux. Here we describe a method for measuring autophagic flux ex vivo that allows more direct observations to be made in situ regarding the state of autophagic flux within the renal cortex of a single animal.
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Autofagosomas/ultraestructura , Autofagia , Corteza Renal/ultraestructura , Microscopía Electrónica de Transmisión , Animales , Autofagosomas/efectos de los fármacos , Autofagosomas/metabolismo , Autofagia/efectos de los fármacos , Proteínas Relacionadas con la Autofagia/genética , Proteínas Relacionadas con la Autofagia/metabolismo , Regulación de la Expresión Génica , Técnicas In Vitro , Corteza Renal/efectos de los fármacos , Corteza Renal/metabolismo , Macrólidos/farmacología , Masculino , Ratones Endogámicos C57BL , Transducción de Señal , Sirolimus/farmacología , Factores de TiempoRESUMEN
The paradigm that high glucose drives overproduction of superoxide from mitochondria as a unifying theory to explain end organ damage in diabetes complications has been tightly held for more than a decade. With the recent development of techniques and probes to measure the production of distinct reactive oxygen species (ROS) in vivo, this widely held dogma is now being challenged with the emerging view that specific ROS moieties are essential for the function of specific intracellular signaling pathways and represent normal mitochondrial function. This review will provide a balanced overview of the dual nature of ROS, detailing current evidence for ROS overproduction in diabetic kidney disease, with a focus on cell types and sources of ROS. The technical aspects of measurement of mitochondrial ROS, both in isolated mitochondria and emerging in vivo methods will be discussed. The counterargument, that mitochondrial ROS production is reduced in diabetic complications, is consistent with a growing recognition that stimulation of mitochondrial biogenesis and oxidative phosphorylation activity reduces inflammation and fibrosis. It is clear that there is an urgent need to fully characterize ROS production paying particular attention to spatiotemporal aspects and to factor in the relevance of ROS in the regulation of cellular signaling in the pathogenesis of diabetic kidney disease. With improved tools and real-time imaging capacity, a greater understanding of the complex role of ROS will be able to guide novel therapeutic regimens.
Asunto(s)
Nefropatías Diabéticas/metabolismo , Hiperglucemia/complicaciones , Riñón/patología , Mitocondrias/metabolismo , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismo , Animales , Nefropatías Diabéticas/complicaciones , Fibrosis , Humanos , Hiperglucemia/etiología , Riñón/metabolismo , Especies Reactivas de Oxígeno/análisis , Transducción de SeñalRESUMEN
Oxidative phosphorylation (OXPHOS) drives ATP production by mitochondria, which are dynamic organelles, constantly fusing and dividing to maintain kidney homoeostasis. In diabetic kidney disease (DKD), mitochondria appear dysfunctional, but the temporal development of diabetes-induced adaptations in mitochondrial structure and bioenergetics have not been previously documented. In the present study, we map the changes in mitochondrial dynamics and function in rat kidney mitochondria at 4, 8, 16 and 32 weeks of diabetes. Our data reveal that changes in mitochondrial bioenergetics and dynamics precede the development of albuminuria and renal histological changes. Specifically, in early diabetes (4 weeks), a decrease in ATP content and mitochondrial fragmentation within proximal tubule epithelial cells (PTECs) of diabetic kidneys were clearly apparent, but no changes in urinary albumin excretion or glomerular morphology were evident at this time. By 8 weeks of diabetes, there was increased capacity for mitochondrial permeability transition (mPT) by pore opening, which persisted over time and correlated with mitochondrial hydrogen peroxide (H2O2) generation and glomerular damage. Late in diabetes, by week 16, tubular damage was evident with increased urinary kidney injury molecule-1 (KIM-1) excretion, where an increase in the Complex I-linked oxygen consumption rate (OCR), in the context of a decrease in kidney ATP, indicated mitochondrial uncoupling. Taken together, these data show that changes in mitochondrial bioenergetics and dynamics may precede the development of the renal lesion in diabetes, and this supports the hypothesis that mitochondrial dysfunction is a primary cause of DKD.