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Increasing evidence identifies dicarbonyl stress from reactive glucose metabolites, such as methylglyoxal (MG), as a major pathogenic link between hyperglycemia and complications of diabetes. MG covalently modifies arginine residues, yet the site specificity of this modification has not been thoroughly investigated. Sites of MG adduction in the plasma proteome were identified using LC-MS/MS analysis in vitro following incubation of plasma proteins with MG. Treatment of plasma proteins with MG yielded 14 putative MG hotspots from five plasma proteins (albumin [nine hotspots], serotransferrin, haptoglobin [2 hotspots], hemopexin, and Ig lambda-2 chain C regions). The search results revealed two versions of MG-arginine modification, dihydroxyimidazolidine (R+72) and hydroimidazolone (R+54) adducts. One of the sites identified was R257 in human serum albumin, which is a critical residue located in drug binding site I. This site was validated as a target for MG modification by a fluorescent probe displacement assay, which revealed significant drug dissociation at 300 µM MG from a prodan-HSA complex (75 µM). Moreover, twelve human plasma samples (six male, six female, with two type 2 diabetic subjects from both genders) were analyzed using multiple reaction monitoring (MRM) tandem mass spectrometry and revealed the presence of the MG-modified albumin R257 peptide. These data provide insights into the nature of the site-specificity of MG modification of arginine, which may be useful for therapeutic treatments that aim to prevent MG-mediated adverse responses in patients.
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Proteínas Sanguíneas/metabolismo , Diabetes Mellitus Tipo 2/sangue , Processamento de Proteína Pós-Traducional , Proteômica , Aldeído Pirúvico/sangue , Arginina , Sítios de Ligação , Biomarcadores/sangue , Cromatografia Líquida de Alta Pressão , Diabetes Mellitus Tipo 2/diagnóstico , Feminino , Ensaios de Triagem em Larga Escala , Humanos , Masculino , Mapeamento de Peptídeos , Ligação Proteica , Carbonilação Proteica , Proteômica/métodos , Albumina Sérica/metabolismo , Albumina Sérica Humana , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em TandemRESUMO
OBJECTIVE: Our objective was to examine the role of hypertriglyceridemia on the capacity of HDL to facilitate ABCA-1 mediated cholesterol efflux in type 2 diabetes (T2DM). METHODS: HDL mediated cholesterol efflux through the ABCA-1 transporter was measured using BHK cell lines in samples of 71 participants with T2DM in the presence or absence of high triglyceride levels (TG). Additionally, HDL mediated efflux was measured in 13 diabetic and non-diabetic participants fasting and four hours after a high-fat test challenge. RESULTS: HDL mediated cholesterol efflux function was increased in participants with T2DM with hypertriglyceridemia when compared to participants with T2DM without hypertriglyceridemia (efflux ratio mean±standard deviation (SD), T2DM+TG: 1.17±0.25 vs. T2DM - TG: 1.03±0.19, p=0.0098). In the fat challenge study, we observed a significant increase in ABCA-1 mediated cholesterol efflux capacity following an ingestion of high-fat test meal by participants in both groups of T2DM (n=6, efflux ratio, mean±SD, pre: 0.86±0.4 vs. post: 1.34±0.6, p=0.01) and non-diabetic participants (n=7, efflux ratio mean±SD pre: 1.24±0.31 vs. post: 1.39±0.42, p=0.04) that was partly explained by the difference in CETP activity (r=0.6, p=0.03). CONCLUSION: Our study suggests that high triglyceride levels facilitate ABCA-1 mediated efflux function of HDL in part by activating CETP.
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Transportador 1 de Cassete de Ligação de ATP/fisiologia , Colesterol/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Hipertrigliceridemia/metabolismo , Lipoproteínas HDL/metabolismo , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Idoso , Animais , Transporte Biológico , Células Cultivadas , Proteínas de Transferência de Ésteres de Colesterol/metabolismo , Cricetinae , Estudos Transversais , Diabetes Mellitus Tipo 2/complicações , Feminino , Humanos , Hipertrigliceridemia/etiologia , Masculino , Pessoa de Meia-IdadeRESUMO
PURPOSE: This article reports the results of a community-based, culturally tailored diabetes prevention program for overweight Mexican American adults on weight loss, waist circumference, diet and physical activity self-efficacy, and diet behaviors. METHODS: The intervention used content from the Diabetes Prevention Program but culturally tailored the delivery methods into a community-based program for Spanish-speaking adults of Mexican descent. The design was a randomized controlled trial (N = 58) comparing the effects of a 5-month educational intervention with an attention control group. The primary study outcome was weight loss. Secondary outcomes included change in waist circumference, body mass index, diet self-efficacy, and physical activity self-efficacy. RESULTS: There were significant intervention effects for weight, waist circumference, body mass index, and diet self-efficacy, with the intervention group doing better than the control group. These effects did not change over time. CONCLUSIONS: Findings support the conclusion that a community-based, culturally tailored intervention is effective in reducing diabetes risk factors in a 5-month program.
Assuntos
Diabetes Mellitus Tipo 2/prevenção & controle , Educação em Saúde , Americanos Mexicanos , Aceitação pelo Paciente de Cuidados de Saúde , Cooperação do Paciente/psicologia , Adulto , Idoso , Glicemia/metabolismo , Índice de Massa Corporal , Cultura , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/psicologia , Dieta , Aconselhamento Diretivo/métodos , Estudos de Viabilidade , Comportamento Alimentar , Feminino , Hemoglobinas Glicadas/metabolismo , Educação em Saúde/métodos , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Americanos Mexicanos/etnologia , Americanos Mexicanos/psicologia , Pessoa de Meia-Idade , Aceitação pelo Paciente de Cuidados de Saúde/etnologia , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Cooperação do Paciente/estatística & dados numéricos , Educação de Pacientes como Assunto , Seleção de Pacientes , Avaliação de Programas e Projetos de Saúde , Autocuidado , Inquéritos e Questionários , Estados Unidos/epidemiologia , Estados Unidos/etnologia , Circunferência da Cintura , Redução de PesoRESUMO
PURPOSE: The purpose of this article is to describe methods used to recruit and retain high-risk, Spanish-speaking adults of Mexican origin in a randomized clinical trial that adapts Diabetes Prevention Program (DPP) content into a community-based, culturally tailored intervention. METHODS: Multiple passive and active recruitment strategies were analyzed for effectiveness in reaching the recruitment goal. Of 91 potential participants assessed for eligibility, 58 participated in the study, with 38 in the intervention and 20 in the attention control group. The American diabetes association risk assessment questionnaire, body mass index, and casual capillary blood glucose measures were used to determine eligibility. RESULTS: The recruitment goal of 50 individuals was met. Healthy living diabetes prevention presentations conducted at churches were the most successful recruiting strategy. The retention goal of 20 individuals was met for the intervention group. Weekly reminder calls were made by the promotora to each intervention participant, and homework assignments were successful in facilitating participant engagement. CONCLUSIONS: A community advisory board made significant and crucial contributions to the recruitment strategies and refinement of the intervention. RESULTS: support the feasibility of adapting the DPP into a community-based intervention for reaching adults of Mexican origin at high risk for developing diabetes.
Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/prevenção & controle , Hemoglobinas Glicadas/metabolismo , Americanos Mexicanos , Adulto , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Cultura , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/etnologia , Estudos de Viabilidade , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Avaliação de Programas e Projetos de Saúde , Autocuidado , Inquéritos e QuestionáriosRESUMO
BACKGROUND/AIMS: Arsenic (As) is linked to insulin resistance in animal studies, but the effect of low-level As exposure on the prevalence of diabetes in humans is uncertain. An optimal method to report inorganic As in humans has not been established. Measurements of As in spot urine are usually adjusted to creatinine (Cr). However, urinary Cr is an independent variable in diabetes. Our aims are to optimize reporting of urinary As in the setting of diabetes and insulin resistance. METHODS: Urinary inorganic As was measured in 24-hour or first-void spot urine from diabetic (n = 31) and non-diabetic (n = 12) subjects and normalized to Cr or specific gravity (SG). The relation of normalized urinary inorganic As to glycemia and surrogate measures of insulin resistance was investigated. Blood pressure, waist circumference, and glycated hemoglobin were also assessed. Homeostasis model assessment was used to determine insulin resistance. RESULTS: A strong correlation was found between spot urinary As adjusted to Cr (R(2) = 0.82) or SG (R(2) = 0.61) to 24-hour urinary As (p < 0.001), while non-adjusted urinary As did not correlate well (R(2) = 0.03, p = 0.46). Adjusting for Cr revealed significant differences in total 24-hour urinary As when comparing diabetic to normal subjects. In contrast, no differences were found when As was adjusted to SG using either 24-hour or spot urine. Moreover, adjusted urinary spot or 24-hour As measures did not correlate with measures of glycemia or insulin resistance. Conclusions: Urinary Cr is an independent variable in diabetes, therefore adjusting spot As for SG is preferred.
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OBJECTIVE: To report a case of erlotinib-associated exacerbation of hypothyroidism complicated by pericardial tamponade. METHODS: We describe the patient's clinical presentation, biochemical workup, and clinical course. RESULTS: Non-small cell lung cancer was diagnosed in a 54-year-old woman. After cisplatin and radiation therapy, she was noted to have subclinical hypothyroidism that did not necessitate treatment. The tyrosine kinase inhibitor erlotinib, 150 mg once daily, was prescribed. Three months later, the patient was documented to have severe hypothyroidism. Levothyroxine was prescribed, but she continued to experience shortness of breath, fatigue, and chest and back pain, which resulted in an emergency department visit. Inpatient workup revealed cardiac tamponade with a large pericardial effusion and a right ventricular diastolic collapse. Pericardiocentesis was performed. CONCLUSIONS: This is the first case report linking erlotinib use and thyroid disease.
Assuntos
Tamponamento Cardíaco/induzido quimicamente , Hipotireoidismo/induzido quimicamente , Quinazolinas/efeitos adversos , Tamponamento Cardíaco/tratamento farmacológico , Tamponamento Cardíaco/terapia , Cloridrato de Erlotinib , Feminino , Humanos , Pessoa de Meia-Idade , Quinazolinas/uso terapêutico , Tiroxina/uso terapêuticoRESUMO
CONTEXT: A close association between insulin resistance and reduced skeletal muscle oxidative capacity has been reported in adult offspring of people with type 2 diabetes (T2D), prompting a hypothesis that insulin resistance may result from mitochondrial dysfunction or vice versa. OBJECTIVE: We determined whether 9 d of intensive exercise training ameliorates the mitochondrial dysfunction and insulin resistance in offspring of T2D. METHODS: We compared the response to 9 d of intensive exercise training in eight (seven females, one male) healthy adult offspring of mothers with T2D with eight (six females, two males) nondiabetic controls. Skeletal muscle mitochondrial ATP production was assessed using a luciferase-based assay, and insulin sensitivity was measured using hyperinsulinemic-euglycemic clamps. RESULTS: Short-term intensive training increased skeletal muscle mitochondrial ATP production and citrate synthase activity similarly in both groups (P < 0.01). In contrast, whereas short-term intensive training reduced the fasting glucose (~5%, P = 0.035) and insulin levels (~40%, P = 0.011) as well as increased the glucose infusion rate during the hyperinsulinemic-euglycemic clamp (~50%, P = 0.028) among controls, no changes in these parameters were observed among offspring except for an increase in fasting glucose (~7%, P = 0.004). CONCLUSION: A short-term intensive exercise training program was equally effective at increasing skeletal muscle oxidative capacity in nondiabetic people and in the offspring of mothers with diabetes. In contrast, the exercise improved insulin sensitivity only in nondiabetic people but not in the offspring of T2D mothers, revealing dissociation between improvements in skeletal muscle mitochondrial function and insulin sensitivity. The exercise effect on mitochondrial function and insulin sensitivity seems to be mediated by different regulatory pathways.
Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Exercício Físico/fisiologia , Insulina/metabolismo , Mitocôndrias/fisiologia , Adulto , Filhos Adultos , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Humanos , Resistência à Insulina/fisiologia , Masculino , Comportamento SedentárioRESUMO
Chronic kidney disease (CKD) is an important risk factor for cardiovascular disease (CVD) and mortality. The increase in CKD in recent decades has paralleled increases in obesity, diabetes, and the metabolic syndrome. Physical inactivity is a modifiable risk factor that may affect the development and course of CKD. It is well established that exercise training improves a number of metabolic factors, including blood pressure and insulin resistance, which would be expected to preserve renal function as well as lower CVD risk. Epidemiological studies have suggested that partaking in vigorous physical activity may protect against kidney disease. However, to date few studies have rigorously measured physical activity levels. Instead, investigators have relied on subjective measures of physical activity and patient recall. This is particularly problematic when attempting to capture low- and very-low-intensity physical activity and in quantifying sedentary behavior. Improvements in vascular endothelial function, insulin sensitivity, adipocytokine profiles, and oxidative stress likely mediate the benefits of physical activity on the kidney. While formal exercise recommendations have been published for diabetes and hypertension, guidelines regarding the optimal type, frequency, intensity and duration of physical activity for preventing CKD have yet to be formalized.
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Recent studies indicate that not all diabetic subjects benefit from aspirin therapy. Our objective is to characterize diabetic subjects with aspirin resistance using urine thromboxane, and VerifyNow measures. Our results suggest that cardiovascular disease, microalbuminuria, poor diabetes control, and increased waist circumference help identify aspirin resistance in diabetes.
Assuntos
Aspirina/uso terapêutico , Angiopatias Diabéticas/prevenção & controle , Resistência a Medicamentos , Inibidores da Agregação Plaquetária/uso terapêutico , Albuminúria/urina , Estudos de Coortes , Angiopatias Diabéticas/sangue , Angiopatias Diabéticas/urina , Feminino , Hemoglobinas Glicadas/análise , Humanos , Resistência à Insulina , Masculino , Pessoa de Meia-Idade , Nefelometria e Turbidimetria , Agregação Plaquetária/efeitos dos fármacos , Tromboxano B2/análogos & derivados , Tromboxano B2/urina , Circunferência da CinturaRESUMO
Aspirin has lower antiplatelet activity in diabetic patients. Our aim is to study the roles of acute hyperglycemia and hyperlipidemia on aspirin function in diabetic subjects with and without cardiovascular disease. Using urine thromboxane (pg/mg creatinine) and VerifyNow (Aspirin Resistance Measures-ARU), we investigated diabetic subjects during a 2-hour glucose challenge (n = 49) or a 4-hour fat challenge (n = 11). All subjects were currently taking aspirin (81 or 325 mg). After fat ingestion, urine thromboxane increased in all subjects (Mean ± SE before: after) (1209 ± 336: 1552 ± 371, P = .01), while we noted a trend increase in VerifyNow measures (408 ± 8: 431 ± 18, P = .1). The response to glucose ingestion was variable. Diabetic subjects with cardiac disease and dyslipidemia increased thromboxane (1693 ± 364: 2799 ± 513, P < .05) and VerifyNow (457.6 ± 22.3: 527.1 ± 25.8, P < .05) measures after glucose. We conclude that saturated fat ingestion increases in vivo thromboxane production despite aspirin therapy.
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Angiotensin II (Ang II) stimulation of the Ang type 1 receptor (AT(1)R) facilitates myocardial remodeling through NADPH oxidase-mediated generation of oxidative stress. Components of the renin-angiotensin system constitute an autocrine/paracrine unit in the myocardium, including renin, which is the rate-limiting step in the generation of Ang II. This investigation sought to determine whether cardiac oxidative stress and cellular remodeling could be attenuated by in vivo renin inhibition and/or AT(1)R blockade in a rodent model of chronically elevated tissue Ang II levels, the transgenic (mRen2)27 rat (Ren2). The Ren2 overexpresses the mouse renin transgene with resultant hypertension, insulin resistance, and cardiovascular damage. Young (6- to 7-wk-old) heterozygous (+/-) male Ren2 and age-matched Sprague-Dawley rats were treated with the renin inhibitor aliskiren, which has high preferential affinity for human and mouse renin, an AT(1)R blocker, irbesartan, or placebo for 3 wk. Myocardial NADPH oxidase activity and immunostaining for NADPH oxidase subunits and 3-nitrotyrosine were evaluated and remodeling changes assessed by light and transmission electron microscopy. Blood pressure, myocardial NADPH oxidase activity and subunit immunostaining, 3-nitrotyrosine, perivascular fibrosis, mitochondrial content, and markers of activity were significantly increased in Ren2 compared with SD littermates. Both renin inhibition and blockade of the AT(1)R significantly attenuated cardiac functional and structural alterations, although irbesartan treatment resulted in greater reductions of both blood pressure and markers of oxidative stress. Collectively, these data suggest that both reduce changes driven, in part, by Ang II-mediated increases in NADPH oxidase and, in part, increases in blood pressure.
Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Receptor Tipo 1 de Angiotensina/metabolismo , Renina/antagonistas & inibidores , Remodelação Ventricular/fisiologia , Amidas/farmacologia , Animais , Animais Geneticamente Modificados , Anti-Hipertensivos/farmacologia , Compostos de Bifenilo/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Fumaratos/farmacologia , Irbesartana , Masculino , Miocárdio/metabolismo , NADPH Oxidases/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Ratos , Ratos Sprague-Dawley , Tetrazóis/farmacologia , Tirosina/análogos & derivados , Tirosina/metabolismo , Remodelação Ventricular/efeitos dos fármacosRESUMO
The cardiometabolic syndrome (CMS), with its increased risk for cardiovascular disease (CVD), nonalcoholic fatty liver disease (NAFLD), and chronic kidney disease (CKD), has become a growing worldwide health problem. Insulin resistance is a key factor for the development of the CMS and is strongly related to obesity, hyperlipidemia, hypertension, type 2 diabetes mellitus (T2DM), CKD, and NAFLD. Insulin resistance in skeletal muscle is particularly important since it is normally responsible for more than 75% of all insulin-mediated glucose disposal. However, the molecular mechanisms responsible for skeletal muscle insulin resistance remain poorly defined. Accumulating evidence indicates that low-grade chronic inflammation and oxidative stress play fundamental roles in the development of insulin resistance, and inflammatory cytokines likely contribute to the link between inflammation, oxidative stress, and skeletal muscle insulin resistance. Understanding the mechanisms by which skeletal muscle tissue develops resistance to insulin will provide attractive targets for interventions, which may ultimately curb this serious problem. This review is focused on the effects of inflammatory cytokines and oxidative stress on insulin signaling in skeletal muscle and consequent development of insulin resistance.
Assuntos
Citocinas/fisiologia , Inflamação/fisiopatologia , Resistência à Insulina/fisiologia , Músculo Esquelético/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Animais , Humanos , Insulina/fisiologia , Estresse Oxidativo/fisiologiaRESUMO
Reduced insulin sensitivity is a key factor in the pathogenesis of type 2 diabetes and hypertension. Skeletal muscle insulin resistance is particularly important for its major role in insulin-mediated glucose disposal. Angiotensin II (ANG II) is integral in regulating blood pressure and plays a role in the pathogenesis of hypertension. In addition, we have documented that ANG II-induced skeletal muscle insulin resistance is associated with generation of reactive oxygen species (ROS). However, the linkage between ROS and insulin resistance in skeletal muscle remains unclear. To explore potential mechanisms, we employed the transgenic TG(mRen2)27 (Ren-2) hypertensive rat, which harbors the mouse renin transgene and exhibits elevated tissue ANG II levels, and skeletal muscle cell culture. Compared with Sprague-Dawley normotensive control rats, Ren-2 skeletal muscle exhibited significantly increased oxidative stress, NF-kappaB activation, and TNF-alpha expression, which were attenuated by in vivo treatment with an angiotensin type 1 receptor blocker (valsartan) or SOD/catalase mimetic (tempol). Moreover, ANG II treatment of L6 myotubes induced NF-kappaB activation and TNF-alpha production and decreased insulin-stimulated Akt activation and GLUT-4 glucose transporter translocation to plasma membranes. These effects were markedly diminished by treatment of myotubes with valsartan, the antioxidant N-acetylcysteine, NADPH oxidase-inhibiting peptide (gp91 ds-tat), or NF-kappaB inhibitor (MG-132). Similarly, NF-kappaB p65 small interfering RNA reduced NF-kappaB p65 subunit expression and nuclear translocation and TNF-alpha production but improved insulin-stimulated phosphorylation (Ser(473)) of Akt and translocation of GLUT-4. These findings suggest that NF-kappaB plays an important role in ANG II/ROS-induced skeletal muscle insulin resistance.
Assuntos
Angiotensina II/farmacologia , Resistência à Insulina/fisiologia , Músculo Esquelético/efeitos dos fármacos , NADPH Oxidases/fisiologia , NF-kappa B/fisiologia , Aldeídos/metabolismo , Animais , Western Blotting , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Transportador de Glucose Tipo 4/biossíntese , Transportador de Glucose Tipo 4/genética , Masculino , Estresse Oxidativo/efeitos dos fármacos , RNA Interferente Pequeno , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Transcrição RelA/biossíntese , Fator de Transcrição RelA/genética , Transfecção , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/fisiologiaAssuntos
Obesidade/terapia , Adolescente , Criança , Pré-Escolar , Humanos , Obesidade/fisiopatologia , Política PúblicaRESUMO
Obesity and insulin resistance (IR) increase the risk for coronary heart disease; however, much of this risk is not attributable to traditional risk factors. We sought to determine whether weight loss associated with supervised aerobic exercise beneficially alters biomarkers of oxidative stress and whether these alterations are associated with improvements in measures of insulin resistance. Twenty-five sedentary and overweight to obese [body mass index (BMI) = 33.0 +/- 0.8 kg/m(2)] individuals, with characteristics of the metabolic syndrome, participated in a 4- to 7-mo weight loss program that consisted of energy restriction (reduced by approximately 500 kcal/day) and supervised aerobic exercise (5 days/wk, 45 min/day at 60% Vo(2 max); approximately 375 kcal/day). IR and insulin sensitivity were assessed by the calculation of the homeostasis model assessment (HOMA) and quantitative insulin sensitivity check index (QUICKI), respectively. Oxidative stress was assessed by oxidized LDL (oxLDL), myeloperoxidase (MPO), and low- and high- density lipoprotein (LDL and HDL) lipid hydroperoxide concentrations in serum. Indexes for antioxidative status included apolipoprotein A1 (apoA1) concentrations and paraoxonase-1 (PON1) activity and protein concentrations. Exercise- and diet-induced weight loss ( approximately 10%) significantly (P < 0.05) increased insulin sensitivity and reduced IR, oxLDL, and LDL lipid hydroperoxides but did not alter HDL lipid hydroperoxides or MPO concentrations. Lifestyle modification impacted systemic antioxidative status by increasing apoA1 concentrations and reducing serum PON1 protein and activity. Changes in oxidative stress were not associated with alterations in HOMA or QUICKI. Diet- and exercise-induced weight loss ( approximately 10%) improves measures of insulin sensitivity and beneficially alters biomarkers of oxidative status.
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Dietoterapia , Terapia por Exercício , Resistência à Insulina , Síndrome Metabólica/terapia , Estresse Oxidativo , Redução de Peso , Adolescente , Adulto , Peso Corporal , Dieta , Feminino , Glucose/metabolismo , Humanos , Lipoproteínas/sangue , Masculino , Pessoa de Meia-IdadeRESUMO
Reduced insulin sensitivity is characteristic of various pathological conditions such as type 2 diabetes mellitus and hypertension. Angiotensin II, acting through its angiotensin type 1 receptor, inhibits the actions of insulin in the vasculature which may lead to deleterious effects such as vascular inflammation, remodeling, endothelial dysfunction, and insulin resistance. In contrast, insulin normally exerts vasodilatory, antiinflammatory, and prosurvival actions. To explore the impact of angiotensin II on insulin signaling, NADPH oxidase-derived reactive oxygen species formation, vascular inflammation, apoptosis, and remodeling, we used transgenic TG(mRen2)27 (Ren2) rats, which harbor the mouse renin transgene and exhibits elevated tissue angiotensin II levels. Compared with Sprague-Dawley controls, Ren2 aortas exhibited greater NADPH oxidase activity, reactive oxygen species levels, C-reactive protein, tumor necrosis factor-alpha expression, apoptosis, and wall thickness, which were significantly attenuated by in vivo treatment with angiotensin type 1 receptor blockade (valsartan) or the superoxide dismutase/catalase mimetic (tempol). There was substantially diminished Akt and endothelial NO synthase activation in Ren2 aortas in response to in vivo insulin stimulation, and this was significantly improved by in vivo treatment with valsartan or tempol. In vivo treatment with valsartan, but not tempol, significantly reduced blood pressure in Ren2 rats. Further, there was reduced insulin induced Akt activation and increased tumor necrosis factor-alpha levels in vascular smooth muscle cells from Ren2 and Sprague-Dawley rats treated with angiotensin II, abnormalities that were abrogated by angiotensin type 1 receptor blockade with valsartan or antioxidant N-acetylcysteine. Collectively, these data suggest that increased angiotensin type 1 receptor/NADPH oxidase activation/reactive oxygen species contribute to vascular insulin resistance, endothelial dysfunction, apoptosis, and inflammation.
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Resistência à Insulina/fisiologia , NADPH Oxidases/metabolismo , Superóxido Dismutase/farmacologia , Tetrazóis/farmacologia , Valina/análogos & derivados , Vasculite/enzimologia , Animais , Animais Geneticamente Modificados , Apoptose/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Western Blotting , Proteína C-Reativa/metabolismo , Células Cultivadas , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Masculino , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/fisiologia , NADPH Oxidases/efeitos dos fármacos , Probabilidade , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Sensibilidade e Especificidade , Valina/farmacologia , Valsartana , Vasculite/tratamento farmacológicoRESUMO
BACKGROUND: Rac1 is a Rho-family small GTP-ase, when activated is pivotal in NAD(P)H oxidase (NOX) activation and generation of reactive oxygen species (ROS). Evidence links Rac1 activation to receptor-mediated albumin endocytosis in the proximal tubule cell (PTC). Thus in states of albumin overload, Rac1 activation could lead to NOX activation and ROS formation in the PTC. Furthermore, accumulating evidence supports that HMG-CoA reductase inhibition may reduce oxidative stress and albuminuria. METHODS: To investigate the role of HMG-CoA reductase inhibition of Rac1 and oxidative stress we used the opossum kidney PTC. ROS generation in the PTC was confirmed using oxidative fluorescent dihydroethidium staining. RESULTS: We observed time-dependent increases in NOX activity with bovine serum albumin (albumin) stimulation (500 microg/dl, maximum at 20 min, p < 0.05) that was inhibited in a concentration-dependent manner with the HMG-CoA reductase inhibitor rosuvastatin (1 microM, p < 0.05). Additionally, the Rac1 inhibitor NSC23766 (100 ng/ml) attenuated albumin activation of NOX. Western blot analysis confirmed Rac1 translocation to plasma membrane in the PTC following albumin stimulation and subsequent inhibition by rosuvastatin and NSC23766. CONCLUSIONS: These data demonstrate that albumin-mediated increases in NOX activity and ROS in PTC are reversed by inhibition of Rac1 signaling with the use of rosuvastatin.
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Albuminas/metabolismo , Endocitose/fisiologia , Túbulos Renais Proximais/metabolismo , NADPH Oxidases/metabolismo , Estresse Oxidativo/fisiologia , Proteínas rac1 de Ligação ao GTP/metabolismo , Albuminas/efeitos dos fármacos , Albuminúria/metabolismo , Albuminúria/patologia , Albuminúria/prevenção & controle , Aminoquinolinas/farmacologia , Animais , Western Blotting , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Células Cultivadas , Meios de Cultura Livres de Soro , Modelos Animais de Doenças , Endocitose/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Fluorbenzenos/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/efeitos dos fármacos , Microscopia Confocal , Gambás , Estresse Oxidativo/efeitos dos fármacos , Pirimidinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Rosuvastatina Cálcica , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Sulfonamidas/farmacologia , Proteínas rac1 de Ligação ao GTP/antagonistas & inibidoresRESUMO
The many similarities between the metabolic syndrome and Cushing's syndrome led to the hypothesis that excess glucocorticoids (GC) are part of the pathogenesis linking their features. We review recent work that confirms the initial similarities (obesity, glucose intolerance, hypertension, and hyperlipidemia) and extends them to associated features of both syndromes (osteopenia, hypogonadism, leukocytosis, depression, and muscle weakness). Recent studies report that these features also occur in subclinical Cushing's syndrome, hypercortisolemic depression, and the transgenic overexpression of 11beta-hydoxysteroid dehydrogenase type 1 (11beta-HSD1) in mouse models of excess GC in adipose tissue. Reducing excess GC--in the clinical syndromes and in the mouse model-reverses many of these features. Because local tissue excess GC may have a central role in the pathogenesis of the metabolic syndrome, selective 11beta-HSD1 inhibitors are under active development by several pharmaceutical companies.
Assuntos
Corticosteroides/sangue , Glândulas Suprarrenais/patologia , Síndrome de Cushing/fisiopatologia , Síndrome Metabólica/fisiopatologia , Esteroides/sangue , Aldosterona/sangue , Doenças Ósseas Metabólicas/fisiopatologia , Endotélio/fisiopatologia , HumanosRESUMO
Renin angiotensin aldosterone system (RAAS) activation plays an essential role in the development of cardiovascular disease (CVD). Multiple pathophysiologic processes are able to activate RAAS, among which hypertension, obesity, diabetes mellitus 2, and chronic kidney disease deserve special attention, because they are the main contributors to CVD. Adding to the well-known effects of RAAS overactivity on the vasculature and water and electrolyte balance, current evidence links abnormal activation of the RAAS to increased production of reactive oxygen species (ROS) and oxidative stress. This association is mediated at least partially through interaction of angiotensin II (Ang II) with its receptor angiotensin receptor 1 (AT1R) in cardiovascular tissue, and subsequent activation of the nicotinamide adenine dinucleotide phosphate (NADPH) enzymatic complex, which finally leads to increased ROS production. This resulting state of enhanced oxidative stress contributes largely to generalized atherosclerosis and finally to CVD. The generation of animal models of increased RAAS and Ang II expression, in particular the Ren2 rodent model, provides important opportunities to better characterize the relationship between this system and the production of ROS. This chapter describes methods to evaluate, characterize, and quantify the activity of the RAAS and NADPH oxidase, as well as the production of ROS production in animal model of RAAS.
Assuntos
Miocárdio/metabolismo , Estresse Oxidativo , Sistema Renina-Angiotensina/fisiologia , Animais , Animais Geneticamente Modificados , Modelos Animais de Doenças , Ventrículos do Coração/citologia , Ventrículos do Coração/metabolismo , Hipertensão/fisiopatologia , NADPH Oxidases/metabolismo , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Renina/genética , Renina/metabolismoRESUMO
BACKGROUND: Angiotensin-II (Ang-II) contributes to cardiac remodeling and left ventricular dysfunction. In contrast, exercise may have beneficial effects on left ventricular structure and function. METHODS AND RESULTS: We investigated the effects of low-intensity exercise training (ET) on in vivo cardiac function in hypertensive TG (mREN-2)27 rats (Ren-2) which develop left ventricular hypertrophy and dysfunction. Ren-2 rats and Sprague Dawley (SD) controls (4-5 weeks) began treadmill exercise every day for 5-6 weeks. Cardiac function was evaluated by echocardiography. Cardiac output and stroke volume were increased by ET in both 8-wk-old SD and Ren-2. Slope of mitral deceleration time, a non-invasive measure of diastolic function, was lower in the Ren-2 rats, but not changed by ET. LV collagen deposition, as assessed by hydroxyproline assay, was not affected by rat strain or ET at 10-11 weeks of age. Left ventricular B-type natriuretic peptide mRNA levels were higher in the Ren-2 rats (100%), but not affected by ET. Both alpha (~14.5 fold) and beta (~2.5 fold) myosin heavy chain mRNA were higher in the LV of Ren-2 rats (p < 0.05), but were not changed by ET. CONCLUSION: Low-intensity exercise training in Ren-2 rats, a model of Ang-II-mediated hypertension, maintains cardiac index and stroke volume in the presence of impaired diastolic function at 8 wks of age.