RESUMEN

The reactive oxygen species (ROS) producing enzyme, NADPH oxidase 4 (Nox4), is upregulated in response to TGFß in lens epithelial cells in vitro, and its selective inhibition was shown to block aspects of TGFß-induced epithelial-mesenchymal transition (EMT). In the present in situ study we validate the role(s) of Nox4 in TGFß-induced lens EMT leading to anterior subcapsular cataract (ASC) formation. Mice overexpressing TGFß in the lens, that develop ASC, were crossed to Nox4-deficient mice. When comparing mice overexpressing TGFß in lens, to mice that were also deficient for Nox4, we see the delayed onset of cataract, along with a delay in EMT protein markers normally associated with TGFß-induced fibrotic cataracts. In the absence of Nox4, we also see elevated levels of ERK1/2 activity that was shown to be required for TGFß/Smad2/3-signaling. qRT-PCR revealed upregulation of Nox2 and its regulatory subunit in TGFß-overexpressing lens epithelial cells devoid of Nox4. Taken together, these findings provide an improved platform to delineate putative Nox4 (and ROS) interactions with Smad2/3 and/or ERK1/2, in particular in the development of fibrotic diseases, such as specific forms of cataract.

Asunto(s)

Catarata/etiología , Transición Epitelial-Mesenquimal/efectos de los fármacos , Cristalino/patología , NADPH Oxidasa 4/fisiología , Especies Reactivas de Oxígeno/metabolismo , Factor de Crecimiento Transformador beta/farmacología , Animales , Western Blotting , Catarata/metabolismo , Células Cultivadas , Electroforesis en Gel de Poliacrilamida , Células Epiteliales/metabolismo , Femenino , Fibrosis , Técnica del Anticuerpo Fluorescente Indirecta , Técnicas de Genotipaje , Cristalino/metabolismo , Masculino , Ratones , Ratones Noqueados , Ratones Transgénicos , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Proteína Smad2/metabolismo , Proteína smad3/metabolismo

RESUMEN

Brackish groundwater (BGW) is increasingly used for water supplies where fresh water is scarce, but the distribution and availability of such resources have not been characterized at the national scale in the United States since the 1960s. Apart from its distribution and accessibility, BGW usability is a function of the chemical requirements of the intended use, chemical characteristics of the resource, and treatment options to make the resource compatible with the use. Here, we discuss relations between these three chemical factors using national-scale examples and local case studies. In a preliminary compilation of BGW data in the United States, five water types accounted for the major-ion composition of 70% of samples. PHREEQC calculations indicate that 57-77% of samples were oversaturated with respect to barite, calcite, or chalcedony. In the study, 5-14% of samples had concentrations of arsenic, fluoride, nitrate, or uranium that exceeded drinking-water standards. In case studies of the potential use of BGW for drinking water, irrigation, and hydraulic fracturing, PHREEQC simulations of a hypothetical treatment process resembling reverse osmosis (RO) showed that BGW had the potential to form various assemblages of mineral deposits (scale) during treatment that could adversely affect RO membranes. Speciation calculations showed that most boron in the irrigation example occurred as boric acid, which has relatively low removal efficiency by RO. Results of this preliminary study indicate that effective national or regional assessments of BGW resources should include geochemical characterizations that are guided in part by specific use and treatment requirements.

Asunto(s)

Agua Dulce , Agua Subterránea , Contaminantes Químicos del Agua , Arsénico , Abastecimiento de Agua

RESUMEN

Diabetes-associated micro- and macrovascular complications contribute to the increased morbidity and mortality observed in diabetes. Diabetes leads to accelerated generation of advanced glycation end products (AGEs) and activation of their receptor, RAGE, as well as activation of NAD(P)H oxidase (Nox), an enzyme dedicated to the production of reactive oxygen species, which ultimately leads to a pro-inflammatory environment characterised by oxidative stress. This review outlines the current evidence about the contribution of and interaction between the AGE-RAGE axis and Nox derived ROS formation in the development and progression of micro- and macrovascular diabetic complications (especially in atherosclerosis and nephropathy), and the mechanisms by which this occurs. We also outline novel treatments targeting the AGE-RAGE axis and specific Nox isoforms, which hold great promise in attenuating the development of diabetes-associated atherosclerosis and diabetic nephropathy.

Asunto(s)

Angiopatías Diabéticas/genética , NADPH Oxidasas/fisiología , Receptor para Productos Finales de Glicación Avanzada/fisiología , Animales , Aterosclerosis/etiología , Aterosclerosis/genética , Aterosclerosis/metabolismo , Angiopatías Diabéticas/metabolismo , Nefropatías Diabéticas/genética , Nefropatías Diabéticas/metabolismo , Productos Finales de Glicación Avanzada/metabolismo , Productos Finales de Glicación Avanzada/fisiología , Humanos , NADPH Oxidasa 1 , Estrés Oxidativo/fisiología , Especies Reactivas de Oxígeno/efectos adversos , Especies Reactivas de Oxígeno/metabolismo

RESUMEN

AIMS/HYPOTHESIS: Enhanced vascular inflammation, immune cell infiltration and elevated production of reactive oxygen species (ROS) contribute significantly to pro-atherogenic responses in diabetes. We assessed the immunomodulatory role of NADPH oxidase (NOX)-derived ROS in diabetes-accelerated atherosclerosis. METHODS: Diabetes was induced in male Apoe(-/-) mice with five daily doses of streptozotocin (55 mg kg(-1) day(-1)). Atherosclerotic plaque size, markers of ROS and immune cell accumulation were assessed in addition to flow cytometric analyses of cells isolated from the adjacent mediastinal lymph nodes (meLNs). The role of NOX-derived ROS was investigated using the NOX inhibitor, GKT137831 (60 mg/kg per day; gavage) administered to diabetic and non-diabetic Apoe(-/-) mice for 10 weeks. RESULTS: Diabetes increased atherosclerotic plaque development in the aortic sinus and this correlated with increased lesional accumulation of T cells and CD11c(+) cells and altered T cell activation in the adjacent meLNs. Diabetic Apoe(-/-) mice demonstrated an elevation in vascular ROS production and expression of the proinflammatory markers monocyte chemoattractant protein 1, vascular adhesion molecule 1 and IFNγ. Blockade of NOX-derived ROS using GKT137831 prevented the diabetes-mediated increase in atherosclerotic plaque area and associated vascular T cell infiltration and also significantly reduced vascular ROS as well as markers of inflammation and plaque necrotic core area. CONCLUSIONS/INTERPRETATION: Diabetes promotes pro-inflammatory immune responses in the aortic sinus and its associated lymphoid tissue. These changes are associated with increased ROS production by NOX. Blockade of NOX-derived ROS using the NOX inhibitor GKT137831 is associated with attenuation of these changes in the immune response and reduces the diabetes-accelerated development of atherosclerotic plaques in Apoe(-/-) mice.

Asunto(s)

Aorta Torácica/patología , Diabetes Mellitus Experimental/tratamiento farmacológico , Angiopatías Diabéticas/tratamiento farmacológico , Inflamación/tratamiento farmacológico , NADPH Oxidasas/efectos de los fármacos , Placa Aterosclerótica/tratamiento farmacológico , Pirazoles/farmacología , Piridinas/farmacología , Especies Reactivas de Oxígeno/metabolismo , Animales , Aorta Torácica/efectos de los fármacos , Apolipoproteínas E/deficiencia , Aterosclerosis , Diabetes Mellitus Experimental/inmunología , Diabetes Mellitus Experimental/patología , Angiopatías Diabéticas/inmunología , Angiopatías Diabéticas/patología , Inmunohistoquímica , Inflamación/inmunología , Inflamación/patología , Masculino , Ratones , NADPH Oxidasas/biosíntesis , Oxidación-Reducción , Placa Aterosclerótica/inmunología , Placa Aterosclerótica/patología , Pirazolonas , Piridonas

RESUMEN

For millennia, the syndrome that has become known as diabetes was considered to be primarily a disease of the urinary system and, by association, of dysfunction in the kidneys (recognized as the source of urine). In the last decade, there has been renewed interest in the role of the kidneys in the development and maintenance of high glucose levels. This has led to the development of novel agents to inhibit sodiumglucose cotransporter 2 (SGLT-2) as a means to control glucose levels and augment calorie-wasting leading to weight loss. However, beyond actions on glycaemic control, inhibition of proximal glucose absorption via SGLT-2 has significant direct effects to attenuate hyperfiltration and reduce renal hypertrophy. Increased distal sodium delivery may also act to suppress the intrarenal renin-angiotensin-aldosterone system, although systemic activity may be modestly increased due to osmotic diuresis. Reducing proximal glucose reabsorption may also protect the tubular cells from exposure to excess glucose and glucose-induced reactive oxygen species. On the other hand, distal glucose delivery following inhibition of SGLT-2 may increase glycogen deposition, the significance of which is unclear. However, subjects with familial glycosuria appear to have a benign renal prognosis. Some studies have demonstrated significant reductions in albumin excretion in various experimental models and as post-hoc observations in clinical trials. Whether these reflect renoprotection or are simply the result of intraglomerular haemodynamic changes remains unclear. Although promising, such actions remain to be established by comprehensive clinical trials with a renal focus, many of which are currently in progress.

Asunto(s)

Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Riñón/efectos de los fármacos , Moduladores del Transporte de Membrana/uso terapéutico , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Animales , Glucemia/metabolismo , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/orina , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/orina , Humanos , Hipoglucemiantes/efectos adversos , Riñón/metabolismo , Moduladores del Transporte de Membrana/efectos adversos , Eliminación Renal/efectos de los fármacos , Transportador 2 de Sodio-Glucosa/metabolismo

RESUMEN

AIMS/HYPOTHESIS: The small, highly conserved vasoactive peptide urotensin II (UII) is upregulated in atherosclerosis. However, its effects in diabetes-associated atherosclerosis have not been assessed. METHODS: Endothelial cells were grown in normal- and high-glucose (5 and 25 mmol/l) media with and without UII (10⁻8 mol/l) and/or the UII receptor antagonist, SB-657510 (10⁻8 mol/l). Apoe knockout (KO) mice with or without streptozotocin-induced diabetes were treated with or without SB-657510 (30 mg kg⁻¹ day⁻¹; n = 20 per group) and followed for 20 weeks. Carotid endarterectomy specimens from diabetic and non-diabetic humans were also evaluated. RESULTS: In high (but not normal) glucose medium, UII significantly increased CCL2 (encodes macrophage chemoattractant protein 1 [MCP-1]) gene expression (human aortic endothelial cells) and increased monocyte adhesion (HUVECs). UII receptor antagonism in diabetic Apoe KO mice significantly attenuated diabetes-associated atherosclerosis and aortic staining for MCP-1, F4/80 (macrophage marker), cyclooxygenase-2, nitrotyrosine and UII. UII staining was significantly increased in carotid endarterectomies from diabetic compared with non-diabetic individuals, as was staining for MCP-1. CONCLUSIONS/INTERPRETATION: This is the first report to demonstrate that UII is increased in diabetes-associated atherosclerosis in humans and rodents. Diabetes-associated plaque development was attenuated by UII receptor antagonism in the experimental setting. Thus UII may represent a novel therapeutic target in the treatment of diabetes-associated atherosclerosis.

Asunto(s)

Aterosclerosis/prevención & control , Diabetes Mellitus Tipo 1/complicaciones , Angiopatías Diabéticas/prevención & control , Endotelio Vascular/efectos de los fármacos , Sustancias Protectoras/uso terapéutico , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Urotensinas/antagonistas & inhibidores , Animales , Aorta/efectos de los fármacos , Aorta/inmunología , Aorta/metabolismo , Aorta/patología , Aterosclerosis/complicaciones , Aterosclerosis/metabolismo , Aterosclerosis/patología , Adhesión Celular/efectos de los fármacos , Células Cultivadas , Cruzamientos Genéticos , Angiopatías Diabéticas/inmunología , Angiopatías Diabéticas/metabolismo , Angiopatías Diabéticas/patología , Endotelio Vascular/inmunología , Endotelio Vascular/metabolismo , Endotelio Vascular/patología , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/inmunología , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Células Endoteliales de la Vena Umbilical Humana/patología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Monocitos/efectos de los fármacos , Monocitos/inmunología , Proyectos Piloto , Sustancias Protectoras/farmacología , Receptores Acoplados a Proteínas G/metabolismo , Sulfonamidas/farmacología , Sulfonamidas/uso terapéutico , Urotensinas/biosíntesis , Urotensinas/metabolismo

RESUMEN

In the 1980s prospective studies using whole populations suggested a relationship between insulin and cardiovascular disease, and these studies proposed that both metabolic and haemodynamic factors were associated with cardiovascular events. The initial analysis of the Paris Prospective Study (Diabetologia 19: 205-210), published in 1980, showed a positive correlation between insulin and cardiovascular events in healthy middle-aged policemen after a 5 year follow-up. In the Bedford Survey (Diabetologia 22: 79-84), also performed in the 1980s, a higher cardiovascular risk was demonstrated in diabetic patients and in those with borderline diabetes; however, in contrast to the Paris Prospective Study, insulin was negatively correlated to cardiovascular endpoints in the Bedford Survey. The initial enthusiasm for insulin as a cardiovascular risk marker was dampened when the 15 year follow-up data of the Paris Prospective Study (Diabetologia 34: 356-361) showed that the correlation between insulin and cardiovascular risk subsided with increased duration of follow-up. Despite the fact that hyperinsulinaemia was always strongly associated with other classical cardiovascular risk factors, univariate analyses usually failed to show a strong correlation between insulin and cardiovascular risk. The San Antonio Heart Study (Diabetologia 34: 416-422) performed in a bi-ethnic population that included a large proportion of Mexican-American participants again emphasised that insulin resistance may be the underlying factor associated with a cluster of metabolic and haemodynamic abnormalities. However, recently performed meta-analyses that included larger studies have not been able to confirm a critical role for insulin levels in cardiovascular risk. Indeed, it has been suggested that proinsulin or other factors may be better markers than insulin per se.

Asunto(s)

Aterosclerosis/sangre , Diabetes Mellitus Tipo 2/sangre , Angiopatías Diabéticas/sangre , Insulina/sangre , Síndrome Metabólico/sangre , Proinsulina/sangre , Aterosclerosis/etiología , Biomarcadores/sangre , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/complicaciones , Angiopatías Diabéticas/etiología , Femenino , Humanos , Resistencia a la Insulina , Masculino , Síndrome Metabólico/complicaciones , Estudios Prospectivos , Medición de Riesgo , Factores de Riesgo

RESUMEN

AIMS/HYPOTHESIS: Diabetic cardiomyopathy is characterised by diastolic dysfunction, oxidative stress, fibrosis, apoptosis and pathological cardiomyocyte hypertrophy. Phosphoinositide 3-kinase (PI3K)(p110α) is a cardioprotective kinase, but its role in the diabetic heart is unknown. The aim of this study was to assess whether PI3K(p110α) plays a critical role in the induction of diabetic cardiomyopathy, and whether increasing PI3K(p110α) activity in the heart can prevent the development of cardiac dysfunction in a setting of diabetes. METHODS: Type 1 diabetes was induced with streptozotocin in adult male cardiac-specific transgenic mice with increased PI3K(p110α) activity (constitutively active PI3K [p110α], caPI3K] or decreased PI3K(p110α) activity (dominant-negative PI3K [p110α], dnPI3K) and non-transgenic (Ntg) mice for 12 weeks. Cardiac function, histological and molecular analyses were performed. RESULTS: Diabetic Ntg mice displayed diastolic dysfunction and increased cardiomyocyte size, expression of atrial and B-type natriuretic peptides (Anp, Bnp), fibrosis and apoptosis, as well as increased superoxide generation and increased protein kinase C ß2 (PKCß2), p22 ( phox ) and apoptosis signal-regulating kinase 1 (Ask1) expression. Diabetic dnPI3K mice displayed an exaggerated cardiomyopathy phenotype compared with diabetic Ntg mice. In contrast, diabetic caPI3K mice were protected against diastolic dysfunction, pathological cardiomyocyte hypertrophy, fibrosis and apoptosis. Protection in diabetic caPI3K mice was associated with attenuation of left ventricular superoxide generation, attenuated Anp, Bnp, PKCß2, Ask1 and p22 ( phox ) expression, and elevated AKT. Further, in cardiomyocyte-like cells, increased PI3K(p110α) activity suppressed high glucose-induced superoxide generation and enhanced mitochondrial function. CONCLUSIONS/INTERPRETATION: These results demonstrate that reduced PI3K activity accelerates the development of diabetic cardiomyopathy, and that enhanced PI3K(p110α) activity can prevent adverse cardiac remodelling and dysfunction in a setting of diabetes.

Asunto(s)

Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Cardiomiopatías Diabéticas/metabolismo , Cardiomiopatías Diabéticas/prevención & control , Superóxidos/metabolismo , Animales , Northern Blotting , Regulación de la Expresión Génica , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Estrés Oxidativo

RESUMEN

Pharmaceutical agonists of peroxisome proliferator-activated receptors (PPARs) are widely used in the management of type 2 diabetes, chiefly as lipid-lowering agents and oral hypoglycaemic agents. Although most of the focus has been placed on their cardiovascular effects, both positive and negative, these agents also have significant renoprotective actions in the diabetic kidney. Over and above action on metabolic control and effects on blood pressure, PPAR agonists also appear to have independent effects on a number of critical pathways that are implicated in the development and progression of diabetic kidney disease, including oxidative stress, inflammation, hypertrophy, and podocyte function. This review will examine these direct and indirect actions of PPAR agonists in the diabetic kidney and explore recent findings of clinical trials of PPAR agonists in patients with diabetes.

RESUMEN

AIMS/HYPOTHESIS: An increase in the production of reactive oxygen species is commonly thought to contribute to the development of diabetic cardiomyopathy. This study aimed to assess whether administration of the antioxidant coenzyme Q(10) would protect the diabetic heart against dysfunction and remodelling, using the db/db mouse model of type 2 diabetes. Furthermore, we aimed to compare the efficacy of coenzyme Q(10) to that of the ACE inhibitor ramipril. METHODS: Six-week-old non-diabetic db/+ mice and diabetic db/db mice received either normal drinking water or water supplemented with coenzyme Q(10) for 10 weeks. Endpoint cardiac function was assessed by echocardiography and catheterisation. Ventricular tissue was collected for histology, gene expression and protein analysis. RESULTS: Untreated db/db diabetic mice exhibited hyperglycaemia, accompanied by diastolic dysfunction and adverse structural remodelling, including cardiomyocyte hypertrophy, myocardial fibrosis and increased apoptosis. Systemic lipid peroxidation and myocardial superoxide generation were also elevated in db/db mice. Coenzyme Q(10) and ramipril treatment reduced superoxide generation, ameliorated diastolic dysfunction and reduced cardiomyocyte hypertrophy and fibrosis in db/db mice. Phosphorylation of Akt, although depressed in untreated db/db mice, was restored with coenzyme Q(10) administration. We postulate that preservation of cardioprotective Akt signalling may be a mechanism by which coenzyme Q(10)-treated db/db mice are protected from pathological cardiac hypertrophy. CONCLUSIONS/INTERPRETATION: These data demonstrate that coenzyme Q(10) attenuates oxidative stress and left ventricular diastolic dysfunction and remodelling in the diabetic heart. Addition of coenzyme Q(10) to the current therapy used in diabetic patients with diastolic dysfunction warrants further investigation.

Asunto(s)

Cardiomegalia/tratamiento farmacológico , Cardiomiopatías Diabéticas/tratamiento farmacológico , Ubiquinona/análogos & derivados , Vitaminas/uso terapéutico , Animales , Antihipertensivos/uso terapéutico , Apoptosis/efectos de los fármacos , Apoptosis/fisiología , Cardiomegalia/diagnóstico por imagen , Cardiomegalia/metabolismo , Cardiomegalia/fisiopatología , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/fisiopatología , Cardiomiopatías Diabéticas/diagnóstico por imagen , Cardiomiopatías Diabéticas/metabolismo , Cardiomiopatías Diabéticas/fisiopatología , Modelos Animales de Enfermedad , Fibrosis Endomiocárdica/tratamiento farmacológico , Fibrosis Endomiocárdica/etiología , Fibrosis Endomiocárdica/metabolismo , Femenino , Hiperglucemia/tratamiento farmacológico , Hiperglucemia/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Peroxidación de Lípido/fisiología , Ratones , Ratones Endogámicos C57BL , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ramipril/uso terapéutico , Superóxidos/antagonistas & inhibidores , Superóxidos/metabolismo , Ubiquinona/uso terapéutico , Ultrasonografía , Remodelación Ventricular/efectos de los fármacos , Remodelación Ventricular/fisiología

RESUMEN

AIMS/HYPOTHESIS: Formation of AGEs is increased in the diabetic milieu, which contributes to accelerated atherogenesis. We studied whether delayed treatment with AGE-inhibiting compounds, alagebrium chloride and pyridoxamine dihydrochloride, affected established atherosclerosis in experimental diabetes in comparison with the angiotensin-converting enzyme inhibitor, quinapril. METHODS: Streptozotocin-induced diabetic male Apoe (-/-) mice (n = 24 per group) received, by oral gavage, from week 10 to 20 of diabetes: no treatment; alagebrium (1 mg kg(-1) day(-1)); pyridoxamine (1 g/l in drinking water); or quinapril (30 mg kg(-1) day(-1)). Atherosclerotic lesion area (en face analysis) was evaluated for all groups. RESULTS: Delayed intervention with alagebrium decreased plaque area in the diabetic Apoe (-/-) mice compared with untreated mice (total plaque area: alagebrium 10.6 ± 1.6%, untreated, 15.1 ± 1.5%, p < 0.05). This anti-atherosclerotic effect was comparable with that achieved with quinapril (quinapril 8.4 ± 1.4%, vs untreated, p < 0.05). Pyridoxamine also attenuated plaque development in diabetic mice (5.7 ± 1.2% vs untreated 11.9 ± 1.1%, p < 0.05). The anti-atherosclerotic effect conferred by alagebrium and quinapril was associated with a significant reduction in vascular oxidative stress and circulating AGEs and methylglyoxal, although preformed AGEs were not removed from the vascular wall with either delayed intervention. CONCLUSIONS/INTERPRETATION: Inhibition of AGE accumulation, using a delayed intervention with alagebrium or pyridoxamine, significantly attenuated the progression of established diabetes-associated atherosclerosis, similar to results obtained with quinapril. These findings provide further evidence that blockade of AGE-mediated pathways may present a novel therapy for the prevention of atherosclerosis in diabetes.

Asunto(s)

Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Apolipoproteínas E/metabolismo , Aterosclerosis/tratamiento farmacológico , Aterosclerosis/etiología , Diabetes Mellitus Experimental/fisiopatología , Animales , Apolipoproteínas E/genética , Aterosclerosis/sangre , Inmunohistoquímica , Masculino , Ratones , Ratones Noqueados , Peptidil-Dipeptidasa A/sangre , Quinapril , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Tetrahidroisoquinolinas/uso terapéutico

RESUMEN

AIMS: To comprehensively characterize large artery biomechanical properties and examine their relationship to cardiac function in patients with Type 2 diabetes mellitus (DM). METHODS: Fifty-five individuals with Type 2 DM were compared with 66 age- and sex-matched healthy control subjects. Arterial biomechanical properties were assessed by systemic arterial compliance (SAC; two-element Windkessel model), carotid-femoral pulse wave velocity (PWVc-f), femoral-dorsalis pedis pulse wave velocity (PWVf-d) and carotid augmentation index. Cardiac structure and function were assessed by echocardiography. RESULTS: Individuals with Type 2 DM had lower SAC and higher PWVc-f when compared with the healthy population. The PWVc-f was significantly lower than the PWVf-d in control individuals, but this difference was not evident in individuals with Type 2 DM due to higher PWVc-f. Augmentation index was similar in both groups, but the time to the first systolic inflection (time to reflection) was shorter in the individuals with Type 2 DM. The individuals with Type 2 DM had a greater prevalence of diastolic abnormalities when compared with the control group. Arterial stiffness indices, including SAC and pulse pressure, correlated with left ventricular filling pressure (defined as peak velocity during early diastolic filling divided by the velocity of movement of the mitral valve annulus in early diastole; r = -0.33 and 0.36 respectively. CONCLUSIONS: Patients with Type 2 DM on standard medication showed preferential stiffening of the large central arteries. However, carotid augmentation index was not different between the two groups and is therefore not a reliable indicator of large artery stiffening in this patient group. Diastolic dysfunction, present in a significant proportion of this population with Type 2 DM, was closely associated with arterial stiffening, suggesting a common aetiology.

Asunto(s)

Aterosclerosis/fisiopatología , Arteria Braquial/fisiopatología , Diabetes Mellitus Tipo 2/fisiopatología , Angiopatías Diabéticas/fisiopatología , Diástole/fisiología , Hipertensión/fisiopatología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Aterosclerosis/etiología , Aterosclerosis/metabolismo , Velocidad del Flujo Sanguíneo/fisiología , Presión Sanguínea/fisiología , Arteria Braquial/metabolismo , Estudios Transversales , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/metabolismo , Angiopatías Diabéticas/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Resistencia Vascular/fisiología , Adulto Joven

RESUMEN

AIMS/HYPOTHESIS: Most of the known actions of angiotensin II have been considered primarily to be the result of angiotensin II subtype 1 receptor activation. However, recent data suggest that the angiotensin II subtype 2 receptor (AT(2)R) may modulate key processes linked to atherosclerosis. The aim of this study was to investigate the role of AT(2)R in diabetes-associated atherosclerosis using pharmacological blockade and genetic deficiency. METHODS: Aortic plaque deposition was assessed in streptozotocin-induced diabetic apolipoprotein E (Apoe) knockout (KO) and At ( 2 ) r (also known as Agtr2)/Apoe double-KO (DKO) mice. Control and diabetic Apoe-KO mice received an AT(2)R antagonist PD123319 (5 mg kg(-1) day(-1)) via osmotic minipump for 20 weeks (n = 7-8 per group). RESULTS: Diabetes was associated with a sixfold increase in plaque area (diabetic Apoe-KO: 12.7 +/- 1.4% vs control Apoe-KO: 2.3 +/- 0.4%, p < 0.001) as well as a significant increase in aortic expression of the gene At ( 2 ) r (also known as Agtr2). The increase in plaque area with diabetes was attenuated in AT(2)R antagonist-treated diabetic Apoe-KO mice (7.1 +/- 0.5%, p < 0.05) and in diabetic At ( 2 ) r/Apoe DKO mice (9.2 +/- 1.3%, p < 0.05). These benefits occurred independently of glycaemic control or BP, and were associated with downregulation of a range of pro-inflammatory cytokines, adhesion molecules, chemokines and various extracellular matrix proteins. CONCLUSIONS/INTERPRETATION: This study provides evidence for AT(2)R playing a role in the development of diabetes-associated atherosclerosis. These findings suggest a potential utility of AT(2)R blockers in the prevention and treatment of diabetic macrovascular complications.

Asunto(s)

Antagonistas de Receptores de Angiotensina , Apolipoproteínas E/genética , Aterosclerosis/genética , Aterosclerosis/prevención & control , Diabetes Mellitus Experimental/metabolismo , Animales , Aorta/metabolismo , Aorta/patología , Peso Corporal , Adhesión Celular , Inhibidores Enzimáticos/farmacología , Imidazoles/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Piridinas/farmacología , Receptores de Angiotensina/deficiencia , Receptores CCR2/metabolismo

RESUMEN

AIMS/HYPOTHESIS: Excess accumulation of vascular extracellular matrix (ECM) is an important pathological process in cardiovascular diseases including diabetes-associated atherosclerosis. We explored how a recently identified molecule, cell division autoantigen 1 (CDA1), influences the profibrotic TGF-beta pathway leading to vascular ECM accumulation. METHODS: Expression levels of genes encoding for CDA1, TGF-beta and connective tissue growth factor (CTGF) were examined in aorta from Apoe(-/-) mice with or without diabetes. We used retroviral and adenoviral constructs to knockdown or overexpress Tspyl2, the gene encoding CDA1, in mouse vascular smooth muscle cells (VSMCs) with or without TGF-beta treatment in order to demonstrate the role of CDA1 in TGF-beta signalling. RESULTS: In vivo studies indicated that the mRNA levels of CDA1-encoding gene Tspyl2 and protein levels of CDA1 were elevated in the aorta of diabetic Apoe(-/-) mice, accompanied by increased levels of Tgf-beta (also known as Tgfb1), Ctgf and ECM accumulation. In vitro studies in vascular cells showed that TGF-beta treatment rapidly increased CDA1 protein levels, which then amplified TGF-beta signalling leading to upregulation of ECM genes. Knockdown of CDA1-encoding gene Tspyl2 to reduce cellular CDA1 level markedly attenuated TGF-beta-stimulated MAD homologue 3 (drosophila; SMAD3) phosphorylation and transcriptional activities. CDA1 overproduction increased and Tspyl2 knockdown decreased expression of TGF-beta receptor type I, TbetarI (also known as Tgfbr1), but not TGF-beta receptor type II, TbetarII (also known as Tgfbr2), providing a mechanism for CDA1's action in modulating TGF-beta signalling. Knockdown of CDA1-encoding gene Tspyl2 also blocked the profibrotic effect of TGF-beta in VSMCs. CONCLUSIONS/INTERPRETATION: CDA1 plays an important role in vascular ECM accumulation by amplifying TGF-beta signalling. This is critical for the profibrotic effect of TGF-beta in the vasculature. CDA1 is therefore a potential target for attenuating vascular ECM accumulation caused by enhanced TGF-beta action, as seen in diabetic atherosclerosis.

Asunto(s)

Aterosclerosis/fisiopatología , Autoantígenos/fisiología , Diabetes Mellitus Experimental/fisiopatología , Angiopatías Diabéticas/fisiopatología , Matriz Extracelular/fisiología , Factor de Crecimiento Transformador beta/fisiología , Animales , Aorta/fisiología , Autoantígenos/genética , Glucemia/metabolismo , Factor de Crecimiento del Tejido Conjuntivo/fisiología , Diabetes Mellitus Experimental/complicaciones , Regulación de la Expresión Génica , Genes Reporteros , Hemoglobina Glucada/metabolismo , Lipoproteínas/sangre , Luciferasas/genética , Ratones , ARN Mensajero/genética , ARN Interferente Pequeño/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/fisiología

RESUMEN

AIMS/HYPOTHESIS: There is convincing evidence that the endothelin system contributes to diabetic nephropathy and cardiovascular disease. This study aimed to assess the effects of the non-peptidergic endothelin receptor A (ETA) antagonist avosentan in a mouse model of accelerated diabetic nephropathy and atherosclerosis in comparison with the ACE inhibitor, quinapril. METHODS: Apolipoprotein E (Apoe) knockout (KO) mice (n = 20 per group, five groups) were randomised to the following groups: non-diabetic controls and streptozotocin-induced diabetic animals gavaged daily for 20 weeks with placebo, avosentan (high dose: 30 mg/kg, or low dose: 10 mg/kg) or quinapril (given in drinking water, 30 mg/kg). RESULTS: BP was unchanged by avosentan treatment but decreased with quinapril treatment. Diabetes-associated albuminuria was significantly attenuated by high-dose avosentan after 10 and 20 weeks of treatment. Diabetic animals showed a decreased creatinine clearance, which was normalised by avosentan treatment. In diabetic mice, high-dose avosentan treatment significantly attenuated the glomerulosclerosis index, mesangial matrix accumulation, glomerular accumulation of the matrix proteins collagen IV, and renal expression of genes encoding connective tissue growth factor, vascular endothelial growth factor, transforming growth factor beta and nuclear factor kappaB (p65 subunit). Furthermore, high-dose avosentan treatment was also associated with reduced expression of the genes for ETA, ETB and angiotensin receptor 1. The renoprotective effects of avosentan were comparable or superior to those observed with quinapril. High-dose avosentan also significantly attenuated diabetes-associated aortic atherosclerosis in Apoe KO mice and reduced macrophage infiltration and aortic nitrotyrosine expression. CONCLUSIONS/INTERPRETATION: This study demonstrates that ETA blockade with avosentan may provide an alternate therapeutic strategy for the treatment of diabetic micro- and macrovascular complications.

Asunto(s)

Apolipoproteínas E/deficiencia , Aterosclerosis/prevención & control , Angiopatías Diabéticas/prevención & control , Nefropatías Diabéticas/prevención & control , Antagonistas de los Receptores de Endotelina , Piridinas/uso terapéutico , Pirimidinas/uso terapéutico , Animales , Antihipertensivos/uso terapéutico , Apolipoproteínas E/genética , Presión Sanguínea/efectos de los fármacos , Nefropatías Diabéticas/patología , Modelos Animales de Enfermedad , Hiperglucemia/genética , Hiperlipidemias/genética , Riñón/efectos de los fármacos , Riñón/patología , Pruebas de Función Renal , Ratones , Ratones Noqueados , Quinapril , Tetrahidroisoquinolinas/uso terapéutico

RESUMEN

AIMS/HYPOTHESIS: We evaluated the anti-atherosclerotic effect of the 3-hydroxy-3-methylglutaryl CoA reductase inhibitor, rosuvastatin, and the angiotensin II receptor blocker (ARB), candesartan, alone and in combination, in the streptozotocin-induced diabetic apolipoprotein E-deficient (Apoe (-/-)) mouse. METHODS: Control and streptozotocin-induced diabetic Apoe (-/-) mice received rosuvastatin (5 mg kg(-1) day(-1)), candesartan (2.5 mg kg(-1) day(-1)), dual therapy or no treatment for 20 weeks. Aortic plaque deposition was assessed by Sudan IV staining and subsequent visual quantification. The abundance of proteins was measured using immunohistochemistry. RESULTS: Diabetes was associated with a fourfold increase in total plaque area. Rosuvastatin attenuated plaque area in diabetic mice in the absence of lipid-lowering effects. The anti-atherosclerotic effect of rosuvastatin was comparable to that observed with candesartan. A similar beneficial effect was seen with dual therapy, although it was not superior to monotherapy. Rosuvastatin treatment was associated with attenuated accumulation of AGE and AGE receptor (RAGE) in plaques. Similar beneficial effects on markers of oxidative stress were seen with the ARB and statin. Candesartan was more effective at reducing macrophage accumulation and collagen I abundance in plaques compared with rosuvastatin. The combined effect of candesartan and rosuvastatin was superior in reducing macrophage infiltration, monocyte chemoattractant protein-1 level, vascular AGE accumulation and RAGE abundance in the vascular wall. Furthermore, the combination tended to be more effective in reducing smooth muscle cell infiltration and connective tissue growth factor abundance in plaques. CONCLUSIONS/INTERPRETATION: Rosuvastatin has direct anti-atherosclerotic effects in diabetic macrovascular disease. These effects are independent of effects on lipids and comparable to the effects observed with candesartan.

Asunto(s)

Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Apolipoproteínas E/deficiencia , Bencimidazoles/uso terapéutico , Diabetes Mellitus/tratamiento farmacológico , Fluorobencenos/uso terapéutico , Productos Finales de Glicación Avanzada/metabolismo , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Inflamación/prevención & control , Estrés Oxidativo/efectos de los fármacos , Pirimidinas/uso terapéutico , Sulfonamidas/uso terapéutico , Tetrazoles/uso terapéutico , Animales , Compuestos de Bifenilo , Vasos Sanguíneos/efectos de los fármacos , Vasos Sanguíneos/patología , Diabetes Mellitus/patología , Modelos Animales de Enfermedad , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Rosuvastatina Cálcica

RESUMEN

Adhesion molecules have been implicated in the development and progression of cardiovascular disease, which is highly prevalent in people with diabetes. Adhesion molecules can mediate adhesion of leukocytes to the endothelium. Furthermore, P-selectin expressed on platelets is able to mediate the adhesion of leukocytes to platelets. In this study, we examine the in-vivo and in-vitro effects of rosiglitazone with particular emphasis on three important adhesion molecules (VCAM-1, ICAM-1 and P-selectin). In the aorta of STZ-diabetic apolipoprotein E-deficient (apoE KO) mice, rosiglitazone significantly reduced both total and arch plaque area. The mechanism for this appeared to be reduced macrophage infiltration into the atherosclerotic plaque which was also associated with reduced mRNA levels for VCAM-1, ICAM-1, MCP-1 and P-selectin in the aorta. In-vitro studies revealed reduced cell adhesion of monocytic cells (THP-1) to fibrinogen and endothelial cells (HUVEC) after incubation with rosiglitazone. Furthermore, the reduction in leukocyte adhesion also correlated with significant reductions in mRNA levels for VCAM-1, ICAM-1 and P-selectin indicating that reduced macrophage infiltration in atherosclerotic plaques may occur as a result of a direct effect of rosiglitazone on adhesion molecules in both monocytes and endothelial cells. Thus, we have shown that rosiglitazone appears to have direct anti-atherosclerotic effects in an animal model of diabetes-associated atherosclerosis which are at least partly due to effects on VCAM-1, ICAM-1, MCP-1 and P-selectin expression which leads to decreased leukocyte adhesion and macrophage infiltration.

Asunto(s)

Aterosclerosis/tratamiento farmacológico , Moléculas de Adhesión Celular/genética , Diabetes Mellitus Experimental/tratamiento farmacológico , Angiopatías Diabéticas/tratamiento farmacológico , Hipoglucemiantes/farmacología , Tiazolidinedionas/farmacología , Animales , Enfermedades de la Aorta/tratamiento farmacológico , Enfermedades de la Aorta/inmunología , Apolipoproteínas E/genética , Aterosclerosis/inmunología , Células Cultivadas , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Diabetes Mellitus Experimental/inmunología , Angiopatías Diabéticas/inmunología , Modelos Animales de Enfermedad , Regulación hacia Abajo , Células Endoteliales/efectos de los fármacos , Células Endoteliales/inmunología , Humanos , Molécula 1 de Adhesión Intercelular/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Selectina-P/genética , Selectina-P/metabolismo , ARN Mensajero/metabolismo , Rosiglitazona , Venas Umbilicales/citología , Molécula 1 de Adhesión Celular Vascular/genética , Vasculitis/tratamiento farmacológico , Vasculitis/inmunología

RESUMEN

Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors affecting the regulation of various genes relevant to the pathogenesis of diabetic complications. A number of drugs have been developed to act as agonists of the three PPARs. To date, PPAR isoforms that have been identified are the alpha, beta/delta, and gamma isosforms. Fenofibrate and gemfibrozil are two drugs that act as PPARalpha agonists and are currently in use in the clinical setting. Rosiglitazone is a PPARgamma agonist also in clinical use. These drugs have proved very useful in regulation of either glucose or lipid metabolism and consequently are used in patients with type 2 diabetes. Here, we will review the anti-atherosclerotic potential of PPAR agonists with particular emphasis on recent studies in an animal model of diabetes-associated atherosclerosis, the streptozotocin diabetic apolipoprotein E deficient mouse. These studies have shown both PPARalpha agonists, gemfibrozil and fenofibrate, confer anti-atherosclerotic effects, partly independent of their metabolic effects. Similar positive findings have also been detected in a dose-dependent manner with the PPARgamma agonist, rosiglitazone. The potential clinical implications of these findings are also discussed in view of the recently reported results of the PROACTIVE and FIELD clinical trials with the PPAR agonists rosiglitazone and fenofibrate respectively.

Asunto(s)

Aterosclerosis/metabolismo , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/metabolismo , Receptores Activados del Proliferador del Peroxisoma/fisiología , Animales , Aterosclerosis/tratamiento farmacológico , Aterosclerosis/etiología , Complicaciones de la Diabetes/tratamiento farmacológico , Complicaciones de la Diabetes/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Humanos , Receptores Activados del Proliferador del Peroxisoma/agonistas

RESUMEN

AIMS/HYPOTHESIS: Plasminogen activator inhibitor-1 (PAI-1, also known as serpin peptidase inhibitor, clade E [nexin, plasminogen activator inhibitor type 1], member 1 [SERPINE1]) plays a pathogenetic role in renal fibrosis. It is upregulated in experimental and human diabetic nephropathy. These studies assessed the effect of PAI-1 deficiency and overproduction on renal disease in experimental diabetes. MATERIALS AND METHODS: Diabetes was induced by injection of streptozotocin in 6-week-old PAI-1-deficient mice, transgenic mice overexpressing Pai-1 and control mice. Animals were killed after 24 weeks of diabetes or after observation alone. RESULTS: Pai-1 mRNA was upregulated in kidneys from genetically normal mice with diabetes and in non-diabetic Pai-1 transgenic mice. PAI-1 was not further increased in kidneys from Pai-1 transgenic mice with diabetes. Diabetes-associated albuminuria and glomerular injury, as well as renal alpha-smooth muscle actin production, were ameliorated in diabetic PAI-1-deficient mice, an amelioration associated with attenuated increases in renal matrix metallopeptidase-2 expression and activity. Diabetic Pai-1 transgenic mice did not develop increased albuminuria or glomerular injury, but the tubulointerstitial area was modestly enhanced. In addition to the findings in diabetic mice, abnormalities also developed in 30-week-old PAI-1-deficient and Pai-1 transgenic mice without diabetes. PAI-1 deficiency resulted in increased tubulointerstitial area, TGFB1 protein and alpha-smooth muscle actin. Non-diabetic 30-week-old Pai-1 transgenic mice developed similar renal abnormalities and increased matrix metallopeptidase-2 activity, together with a modest increase in serum glucose and HbA(1c). CONCLUSIONS/INTERPRETATION: These results demonstrate that endogenous PAI-1 deficiency protects mice from glomerular injury in longer term diabetes and that endogenous PAI-1 maintains normal renal interstitial structure in ageing not associated with diabetes.

Asunto(s)

Diabetes Mellitus Experimental/fisiopatología , Nefropatías Diabéticas/genética , Inhibidor 1 de Activador Plasminogénico/genética , Animales , Cruzamientos Genéticos , Diabetes Mellitus Experimental/patología , Nefropatías Diabéticas/patología , Nefropatías Diabéticas/prevención & control , Inmunohistoquímica , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Inhibidor 1 de Activador Plasminogénico/deficiencia , ARN Mensajero/genética , Albúmina Sérica/metabolismo

Asunto(s)

Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Neprilisina/antagonistas & inhibidores , Tiazoles/uso terapéutico , Presión Sanguínea/efectos de los fármacos , Humanos , Hipertensión/tratamiento farmacológico , Hipertensión/enzimología , Hipertensión/fisiopatología , Resultado del Tratamiento