Diabetes induces modifications in costameric proteins and increases cardiomyocyte stiffness.

Several studies have demonstrated that diabetes mellitus can increase the risk of cardiovascular disease and remains the principal cause of death in these patients. Costameres connect the sarcolemma with the cytoskeleton and extracellular matrix, facilitating the transmission of mechanical forces and cell signaling. They are related to cardiac physiology because individual cardiac cells are connected by intercalated discs that synchronize muscle contraction. Diabetes impacts the nanomechanical properties of cardiomyocytes, resulting in increased cellular and left ventricular stiffness, as evidenced in clinical studies of these patients. The question of whether costameric proteins are affected by diabetes in the heart has not been studied. This work analyzes whether type 1 diabetes mellitus (T1DM) modifies the costameric proteins and coincidentally changes the cellular mechanics in the same cardiomyocytes. The samples were analyzed by immunotechniques using laser confocal microscopy. Significant statistical differences were found in the spatial arrangement of the costameric proteins. However, these differences are not due to their expression. Atomic force microscopy was used to compare intrinsic cellular stiffness between diabetic and normal cardiomyocytes and obtain the first elasticity map sections of diabetic living cardiomyocytes. Data obtained demonstrated that diabetic cardiomyocytes had higher stiffness than control. The present work shows experimental evidence that intracellular changes related to cell-cell and cell-extracellular matrix communication occur, which could be related to cardiac pathogenic mechanisms. These changes could contribute to alterations in the mechanical and electrical properties of cardiomyocytes and, consequently, to diabetic cardiomyopathy.NEW & NOTEWORTHY The structural organization of cardiomyocyte proteins is critical for their efficient functioning as a contractile unit in the heart. This work shows that diabetes mellitus induces significant changes in the spatial organization of costamere proteins, t tubules, and intercalated discs. We obtained the first elasticity map sections of living diabetic cardiomyocytes. The results show statistical differences in the map sections of diabetic and control cardiomyocytes, with diabetic cardiomyocytes being stiffer than normal ones.

The association of diabetic peripheral neuropathy with cardiac autonomic neuropathy in individuals with diabetes mellitus: A systematic review.

This systematic review aimed to explore the relationship between diabetic peripheral neuropathy (DPN) and cardiac autonomic neuropathy (CAN) in individuals with type 1 and 2 diabetes mellitus (DM). METHODS: The systematic review follow the protocol registered in Prospero (CRD42020182899). Two authors independently searched the PubMed, Scopus, Embase, Cochrane, and Web of Science databases. Discrepancies were resolved by a third author. The review included observational studies investigating the relationship between CAN and DPN in individuals with DM. RESULTS: Initially, out of 1165 studies, only 16 were selected, with 42.8 % involving volunteers with one type of diabetes, 14.3 % with both types of diabetes and 14.3 % not specify the type. The total number of volunteers was 2582, mostly with type 2 DM. It was analyzed that there is a relationship between CAN and DPN. It was observed that more severe levels of DPN are associated with worse outcomes in autonomic tests. Some studies suggested that the techniques for evaluating DPN might serve as risk factors for CAN. CONCLUSION: The review presents a possible relationship between DPN and CAN, such as in their severity.

NLRP3 inflammasome mechanism and therapeutic targets in diabetic cardiomyopathy.

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes caused by oxidative stress, inflammation, insulin resistance, myocardial fibrosis, and lipotoxicity; its nature is insidious, complex and difficult to treat. NLRP3 inflammasome triggers the maturation and release of pro-inflammatory cytokines, participates in pathophysiological processes such as insulin resistance and myocardial fibrosis, in addition to being closely related to the development and progression of diabetic cardiomyopathy. The development of inhibitors targeting specific aspects of inflammation suggests that NLRP3 inflammasome can be used to treat diabetic cardiomyopathy. This paper aims to summarize NLRP3 inflammasome mechanism and therapeutic targets in diabetic cardiomyopathy, and to provide new suggestions for the treatment of this disease.

La cardiomiopatía diabética es una complicación grave de la diabetes causada por estrés oxidativo, inflamación, resistencia a la insulina, fibrosis miocárdica y lipotoxicidad. Se trata de un padecimiento insidioso, complejo y difícil de tratar. El inflamasoma NLRP3 desencadena la maduración y liberación de citoquinas proinflamatorias, participa en procesos fisiopatológicos como la resistencia a la insulina y la fibrosis miocárdica, además de estar estrechamente relacionado con la aparición y progresión de la cardiomiopatía diabética. El desarrollo de inhibidores dirigidos a aspectos específicos de la inflamación sugiere que el inflamasoma NLRP3 puede utilizarse para tratar la cardiomiopatía diabética. Este artículo pretende resumir el mecanismo y las dianas terapéuticas del inflamasoma NLRP3 en la cardiomiopatía diabética, así como aportar nuevas sugerencias para el tratamiento de esta enfermedad.

Diabetes, heart damage, and angiotensin II. What is the relationship link between them? A minireview.

Cardiovascular complications are the main cause of mortality and morbidity in the diabetic patients, in whom changes in myocardial structure and function have been described. Numerous molecular mechanisms have been proposed that could contribute to the development of a cardiac damage. In this regard, angiotensin II (Ang II), a proinflammatory peptide that constitutes the main effector of the renin-angiotensin system (RAS) has taken a relevant role. The aim of this review was to analyze the role of Ang II in the different biochemical pathways that could be involved in the development of cardiovascular damage during diabetes. We performed an exhaustive review in the main databases, using the following terms: angiotensin II, cardiovascular damage, renin angiotensin system, inflammation, and diabetes mellitus. Classically, the RAS has been defined as a complex system of enzymes, receptors, and peptides that help control the blood pressure and the fluid homeostasis. However, in recent years, this concept has undergone substantial changes. Although this system has been known for decades, recent discoveries in cellular and molecular biology, as well as cardiovascular physiology, have introduced a better understanding of its function and relationship to the development of the diabetic cardiomyopathy.

Mesenchymal Stem Cell Therapy in Diabetic Cardiomyopathy.

The incidence and prevalence of diabetes mellitus (DM) are increasing worldwide, and the resulting cardiac complications are the leading cause of death. Among these complications is diabetes-induced cardiomyopathy (DCM), which is the consequence of a pro-inflammatory condition, oxidative stress and fibrosis caused by hyperglycemia. Cardiac remodeling will lead to an imbalance in cell survival and death, which can promote cardiac dysfunction. Since the conventional treatment of DM generally does not address the prevention of cardiac remodeling, it is important to develop new alternatives for the treatment of cardiovascular complications induced by DM. Thus, therapy with mesenchymal stem cells has been shown to be a promising approach for the prevention of DCM because of their anti-apoptotic, anti-fibrotic and anti-inflammatory effects, which could improve cardiac function in patients with DM.

Ca2+ mishandling and mitochondrial dysfunction: a converging road to prediabetic and diabetic cardiomyopathy.

Diabetic cardiomyopathy is defined as the myocardial dysfunction that suffers patients with diabetes mellitus (DM) in the absence of hypertension and structural heart diseases such as valvular or coronary artery dysfunctions. Since the impact of DM on cardiac function is rather silent and slow, early stages of diabetic cardiomyopathy, known as prediabetes, are poorly recognized, and, on many occasions, cardiac illness is diagnosed only after a severe degree of dysfunction was reached. Therefore, exploration and recognition of the initial pathophysiological mechanisms that lead to cardiac dysfunction in diabetic cardiomyopathy are of vital importance for an on-time diagnosis and treatment of the malady. Among the complex and intricate mechanisms involved in diabetic cardiomyopathy, Ca2+ mishandling and mitochondrial dysfunction have been described as pivotal early processes. In the present review, we will focus on these two processes and the molecular pathway that relates these two alterations to the earlier stages and the development of diabetic cardiomyopathy.

Stingless bee propolis, metformin, and their combination alleviate diabetic cardiomyopathy

Abstract Background and aim: Stingless bee propolis, a resinous compound processed by mandibular secretion of stingless bees, is used for maintenance of hygiene and stability of beehives. Research on stingless bee propolis shows therapeutic properties attributed to polyphenols exhibiting antioxidative, antihyperglycemic and antiischemic effect. However, the cardioprotective effect of stingless bee propolis on diabetic cardiomyopathy is unknown. Methods: Adult male Sprague Dawley rats were randomised to five groups: normal group, diabetic group, diabetic given metformin (DM+M), diabetic given propolis (DM+P) and diabetic given combination therapy (DM+M+P) and treated for four weeks. Body weight, fasting blood glucose, food and water intake were taken weekly. At the end of experiment, biomarkers of oxidative damage were measured in serum and heart tissue. Antioxidants in heart tissue were quantified. Part of left ventricle of heart was processed for histological staining including Haematoxylin and Eosin (H&E) stain for myocyte size and Masson's Trichrome (MT) stain for heart fibrosis and perivascular fibrosis. Results: Propolis alleviated features of diabetic cardiomyopathy such as myocyte hypertrophy, heart fibrosis and perivascular fibrosis associated with improvement in antioxidative status. Conclusion: This study reports beneficial effect of propolis and combination with metformin in alleviating histopathological feature of diabetic cardiomyopathy by modulating antioxidants, making propolis an emerging complementary therapy.

Papel do strain no diagnóstico precoce da cardiomiopatia diabética / Role of strain in the early diagnosis of diabetic cardiomyopathy

Fundamento: A ecocardiografia avançada com utilização de strain miocárdico bi e tridimensional propõe identificar a disfunção sistólica subclínica em diversas condições clínicas. No diabetes mellitus, seu papel é de grande interesse para diagnóstico precoce de cardiomiopatia diabética. Contudo, há grande heterogeneidade nos artigos publicados. Objetivo: Realizar uma revisão sistemática, para avaliar o papel atual da avaliação com strain nos pacientes com diabetes mellitus. Métodos: Após revisão sistemática em cinco bancos de dados, 19 estudos que utilizaram strain bidimensional e oito estudos que utilizaram strain tridimensional foram incluídos. Resultados:Na avaliação por strain bidimensional, a amostra totalizou 1.774 indivíduos com diabetes mellitus, com idade média de 57,1 anos e mediana de 55 anos, com equilíbrio em relação ao sexo dos participantes (47,5% do sexo feminino). Nos estudos que utilizaram strain tridimensional, foram incluídos 488 indivíduos com diabetes, com idade média de 55,7 anos e mediana de 63 anos, também com equilíbrio entre o sexo dos pacientes (51% do sexo feminino). O strain global longitudinal foi o marcador de deformação miocárdica que mais frequentemente conseguiu demonstrar diferença entre grupos com indivíduos diabéticos e controles. Conclusão: O strain miocárdico por speckle tracking bi e tridimensional permite identificar disfunção sistólica subclínica em pacientes diabéticos, o que se torna mais marcante nos pacientes com mais fatores de risco associados e com remodelamento ventricular.(AU)

Background: Advanced echocardiography using two- and three-dimensional myocardial strain proposes to identify subclinical systolic dysfunction in different clinical conditions. Strain assessment plays an important role in the early diagnosis of diabetic cardiomyopathy in diabetes mellitus (DM). However, the findings of published articles are heterogeneous. Here we conducted a systematic review to analyze the current role of strain assessment in patients with DM. Methods: This systematic review of five databases identified 19 studies that used twodimensional strain and 8 studies that used three-dimensional strain. Results: The studies of two-dimensional strain included 1,774 DM patients (mean age, 57.1 years; median age, 55 years; 47.5% women), while those of three-dimensional strain included 488 DM patients (mean age, 55.7 years; median age, 63 years; 51% women). Global longitudinal strain was the myocardial deformation marker that differed most frequently between the DM and control groups. Conclusion: Myocardial strain imaging by two- and three-dimensional speckle tracking echocardiography allows the identification of subclinical systolic dysfunction in DM patients, and differences become more marked when associated with risk factors and ventricular remodeling.(AU)

Vitamin D Deficiency in Patients with Diabetes in French Guiana: Epidemiology and Relation with Microvascular and Macrovascular Complications.

Vitamin D (VD) insufficiency is common among patients with diabetes in French Guiana. The study aimed to evaluate the prevalence of VD deficiency in the different type of diabetes encountered and to analyze the relationship between VD deficiency and diabetes complications. METHODS: An observational study was conducted between May 2019 and May 2020 in French Guiana, based on data from the CODIAM study (Diabetes Cohort in French Amazonia), describing the characteristics of patients with diabetes mellitus. Among 600 patients enrolled with diabetes, 361 had an available VD assay. RESULTS: The mean 25(OH)VD (hydroxycalciferol) level was 27.9 ng/mL. The level of VD was inversely proportional to the HbA1c (glycated hemoglobin) level. Patients with angina pectoris had a greater proportion of deficiencies VD < 20 ng/mL than those without angina. By contrast, patients with retinopathy had higher vitamin D concentrations than those without retinopathy. There was no association between vitamin D and arteriopathy, stroke, nephropathy and polyneuropathy. VD deficiency was more frequent in women, and in patients with a high school education. CONCLUSION: The prevalence of VD deficiency was high in patients with diabetes in French Guiana, emphasizing the importance of VD supplementation.

Combination of Dendrobium Mixture and Metformin Curbs the Development and Progression of Diabetic Cardiomyopathy by Targeting the lncRNA NEAT1.

OBJECTIVES: This study aimed to explore the efficacy of combination treatment with dendrobium mixture and metformin (Met) in diabetic cardiomyopathy (DCM) and its effects on NEAT1 and the Nrf2 signaling pathway. METHODS: H9c2 cells were maintained in medium supplemented with either low (5.5 mmol/L) or high (50 mmol/L) glucose. Male Sprague-Dawley rats were fed a high-glucose diet and administered a single, low dose of streptozotocin (35 mg/kg) via intraperitoneal injection to induce the development of DM. After induction of DM, the rats were treated with dendrobium mixture (10 g/kg) and Met (0.18 g/kg) daily for 4 weeks. Next, quantitative reverse transcription (qRT)-PCR and western blotting were performed to evaluate the expression levels of target genes and proteins. Flow cytometry was performed to assess apoptosis, and hematoxylin and eosin staining was performed to evaluate the morphological changes in rat cardiac tissue. RESULTS: In patients with diabetes mellitus (DM) and myocardial cells and heart tissues from rats with high glucose-induced DM, NEAT1 was downregulated, and the expression levels of Nrf2 were decreased (p<0.01, p<0.001). The combination of dendrobium mixture and Met upregulated the expression of NEAT1 which upregulated Nrf2 by targeting miR-23a-3p, resulting in reduced apoptosis and improved cardiac tissue morphology (p<0.01, p<0.001). CONCLUSION: Dendrobium mixture and Met upregulated the expression of NEAT1 in DCM, thereby inhibiting apoptosis of myocardial cells.

Glucose-lowering Drugs and Hospitalization for Heart Failure: A Systematic Review and Additive-effects Network Meta-analysis With More Than 500 000 Patient-years.

BACKGROUND: Sodium glucose co-transporter 2 inhibitors (SGLT2is) prevent hospitalization resulting from heart failure (HHF). However, patients with type 2 diabetes mellitus use multiple antihyperglycemic drugs to achieve glycosylated hemoglobin (HbA1c) targets. In these drug combinations, the risk of HHF is unpredictable and so is the parallel effect of glucose-lowering. PURPOSE: To examine the impact of antihyperglycemic drugs and their association on HHF. DATA SOURCES: Forty randomized controlled trials (RCTs) reporting HHF. STUDY SELECTION: Published RCTs were the data source. DATA EXTRACTION: Incidence rates of HHF. DATA SYNTHESIS: Random additive-effects network meta-analysis showed that metformin (P = 0.55), sulfonylureas (P = 0.51), glucagon-like peptide-1 receptor-agonist (P = 0.16), and dipeptidyl peptidase 4 inhibitors (DPP4is; P = 0.54) were neutral on the risk of HHF. SGLT2is and SGLT2is + DPP4is reduced the risk of HHF with a hazard ratio (HR) of 0.68 (95% CI, 0.60-0.76; P < 0.0001) and 0.70 (95% CI, 0.60-0.81; P < 0.0001), respectively. Increased risk of HHF was associated with thiazolidinediones (TZDs) as monotherapy or in combination with DPP4is (HR: 1.45; 95% CI, 1.18-1.78; P = 0.0004) and 1.49 (95% CI, 1.18-1.88; P = 0.0008), respectively. Regardless of the therapy, a 1% reduction in HbA1c reduced the risk of HHF by 31.3% (95% CI, 9-48; P = 0.009). LIMITATIONS: There are no data to verify drug combinations available for clinical use and to discriminate the effect of drugs within each of the therapeutic classes. CONCLUSIONS: The risk of HHF is reduced by SGLT2is as monotherapy or in combination with DPP4is and increased by TZDs as monotherapy or in combination. Glucose-lowering provides an additive effect of reducing HHF.

The role of mitochondria in metabolic disease: a special emphasis on heart dysfunction.

Metabolic diseases (MetDs) embrace a series of pathologies characterized by abnormal body glucose usage. The known diseases included in this group are metabolic syndrome, prediabetes and diabetes mellitus types 1 and 2. All of them are chronic pathologies that present metabolic disturbances and are classified as multi-organ diseases. Cardiomyopathy has been extensively described in diabetic patients without overt macrovascular complications. The heart is severely damaged during the progression of the disease; in fact, diabetic cardiomyopathies are the main cause of death in MetDs. Insulin resistance, hyperglycaemia and increased free fatty acid metabolism promote cardiac damage through mitochondria. These organelles supply most of the energy that the heart needs to beat and to control essential cellular functions, including Ca2+ signalling modulation, reactive oxygen species production and apoptotic cell death regulation. Several aspects of common mitochondrial functions have been described as being altered in diabetic cardiomyopathies, including impaired energy metabolism, compromised mitochondrial dynamics, deficiencies in Ca2+ handling, increases in reactive oxygen species production, and a higher probability of mitochondrial permeability transition pore opening. Therefore, the mitochondrial role in MetD-mediated heart dysfunction has been studied extensively to identify potential therapeutic targets for improving cardiac performance. Herein we review the cardiac pathology in metabolic syndrome, prediabetes and diabetes mellitus, focusing on the role of mitochondrial dysfunctions.

Heart Failure and Diabetes: Perspective of a Dangerous Association.

The relationship between diabetes and risk of heart failure has been described in previous trials, releasing the importance of the hyperglycemic state that, added to other risk factors, favors the development of coronary heart disease. The mechanism by which, in the absence of hypertension, obesity and/or dyslipidemia, diabetic patients develop cardiomyopathy has been less studied. Recently, the Sodium Glucose Co-transporter type 2 inhibitors (SGLT2 inhibitors) used for the treatment of heart failure patients with or without diabetes has been a breakthrough in the field of medicine. This review describes the established pathophysiology of diabetic cardiomyopathy and SGLT2 inhibitors, their mechanisms of action, and benefits in this group of patients.

Cardioprotector effect of phosphodiesterase 5 inhibitors in experimental model for diabetes mellitus / Efeito cardioprotetor dos inibidores da fosfodiesterase 5 em modelo de diabetes mellitus experimental

Diabetes mellitus (DM) is considered a 21st century pandemic and is often associated with cardiovascular disease (CVD). The aim of this integrative review was to analyze the cardioprotective effects of phosdodiesterase-5 (PDE5i) inhibitors in experimental diabetes models. The articles were selected from the PubMed, SciELO and LILACS databases from 2014 to 2019. The following descriptors were used in combination with the Boolean operators: Diabetes mellitus experimental AND Phosphodiesterase 5 inhibitors; Diabetic cardiomyopathies AND Phosphodiesterase 5 inhibitors. An initial sample of 155 articles was obtained, of which six met the criteria for the synthesis of the review. The studies analyzed showed that treatment with PDE5i in experimental models, resulted in positive effects on cardiac function and metabolic parameters. Similar results have also been seen in humans. The reduction in cardiac hypertrophy, apoptosis of cardiomyocytes, pro-inflammatory factors and oxidative stress and the modulation of transcription factors involved in diabetes homeostasis, were prevalent among studies. The mechanisms of action involved in cardioprotection have not yet been fully elucidated, however the restoration of the activated cyclic guanosine monofate (cGMP) pathway by soluble guanylate cyclase (sGC) via nitric oxide (NO) was a common mechanism among the studies.

O Diabetes mellitus (DM) é considerado uma pandemia do século XXI e está frequentemente associado às doenças cardiovasculares (DCVs). O objetivo desta revisão integrativa foi analisar os efeitos cardioprotetores de inibidores da fosdodiesterase 5 (PDE5i) em modelos de diabetes experimental. Os artigos foram selecionados nas bases de dados PubMed, SciElo e LILACS no período de 2014 a 2019. Foram utilizados os seguintes descritores combinados com os operadores booleanos: Diabetes mellitus experimental AND Phosphodiesterase 5 inhibitors; Diabetic cardiomyopathies AND Phosphodiesterase 5 inhibitors. Foi obtida uma amostra inicial de 155 artigos, dos quais seis se enquadraram nos critérios para a síntese da revisão. Os estudos analisados evidenciaram que o tratamento com os PDEi5 em modelos experimentais, resultou em efeitos positivos sobre a função cardíaca e parâmetros metabólicos. Resultados semelhantes também foram observados em humanos. A redução da hipertrofia cardíaca, apoptose de cardiomiócitos, fatores pró-inflamatórios e estresse oxidativo e a modulação de fatores de transcrição envolvidos na homeostasia do diabetes, foram achados prevalentes entre os estudos. Os mecanismos de ação envolvidos na cardioproteção ainda não foram totalmente elucidados, contudo a restauração da via da guanosina monofato cíclica ativada (GMPc) pela Guanilato ciclase solúvel (GCs) via Óxido Nítrico (NO) foi um mecanismo comum entre os estudos.

Mitochondrial calcium handling and heart disease in diabetes mellitus.

Diabetes mellitus-induced heart disease, including diabetic cardiomyopathy, is an important medical problem and is difficult to treat. Diabetes mellitus increases the risk for heart failure and decreases cardiac myocyte function, which are linked to changes in cardiac mitochondrial energy metabolism. The free mitochondrial calcium concentration ([Ca2+]m) is fundamental in activating the mitochondrial respiratory chain complexes and ATP production and is also known to regulate the activity of key mitochondrial dehydrogenases. The mitochondrial calcium uniporter complex (MCUC) plays a major role in mediating mitochondrial Ca2+ import, and its expression and function therefore may have a marked impact on cardiac myocyte metabolism and function. Here, we summarize the pathophysiological role of [Ca2+]m handling and MCUC in the diabetic heart. In addition, we evaluate potential therapeutic targets, directed to the machinery that regulates mitochondrial calcium handling, to alleviate diabetes-related cardiac disease.

Combination of Dendrobium Mixture and Metformin Curbs the Development and Progression of Diabetic Cardiomyopathy by Targeting the lncRNA NEAT1

OBJECTIVES: This study aimed to explore the efficacy of combination treatment with dendrobium mixture and metformin (Met) in diabetic cardiomyopathy (DCM) and its effects on NEAT1 and the Nrf2 signaling pathway. METHODS: H9c2 cells were maintained in medium supplemented with either low (5.5 mmol/L) or high (50 mmol/L) glucose. Male Sprague-Dawley rats were fed a high-glucose diet and administered a single, low dose of streptozotocin (35 mg/kg) via intraperitoneal injection to induce the development of DM. After induction of DM, the rats were treated with dendrobium mixture (10 g/kg) and Met (0.18 g/kg) daily for 4 weeks. Next, quantitative reverse transcription (qRT)-PCR and western blotting were performed to evaluate the expression levels of target genes and proteins. Flow cytometry was performed to assess apoptosis, and hematoxylin and eosin staining was performed to evaluate the morphological changes in rat cardiac tissue. RESULTS: In patients with diabetes mellitus (DM) and myocardial cells and heart tissues from rats with high glucose-induced DM, NEAT1 was downregulated, and the expression levels of Nrf2 were decreased (p<0.01, p<0.001). The combination of dendrobium mixture and Met upregulated the expression of NEAT1 which upregulated Nrf2 by targeting miR-23a-3p, resulting in reduced apoptosis and improved cardiac tissue morphology (p<0.01, p<0.001). CONCLUSION: Dendrobium mixture and Met upregulated the expression of NEAT1 in DCM, thereby inhibiting apoptosis of myocardial cells.

New Benzofuran N-Acylhydrazone Reduces Cardiovascular Dysfunction in Obese Rats by Blocking TNF-Alpha Synthesis.

INTRODUCTION: Diabetic obese patients are susceptible to the development of cardiovascular disease, including hypertension and cardiac dysfunction culminating in diabetic cardiomyopathy (DC), which represents a life-threatening health problem with increased rates of morbidity and mortality. The aim of the study is to characterize the effects of a new benzofuran N-acylhydrazone compound, LASSBio-2090, on metabolic and cardiovascular alterations in Zucker diabetic fatty (ZDF) rats presenting DC. METHODS: Male non-diabetic lean Zucker rats (ZL) and ZDF rats treated with vehicle (dimethylsulfoxide) or LASSBio-2090 were used in this study. Metabolic parameters, cardiovascular function, left ventricle histology and inflammatory protein expression were analyzed in the experimental groups. RESULTS: LASSBio-2090 administration in ZDF rats reduced glucose levels to 85.0 ± 1.7 mg/dL (p < 0.05). LASSBio-2090 also lowered the cholesterol and triglyceride levels from 177.8 ± 31.2 to 104.8 ± 5.3 mg/dL and from 123.0 ± 11.4 to 90.9 ± 4.8 mg/dL, respectively, in obese diabetic rats (p < 0.05). LASSBio-2090 normalized plasma insulin, insulin sensitivity and endothelial function in aortas from diabetic animals (p < 0.05). It also enhanced systolic and diastolic left-ventricular function and reverted myocardial remodeling by blocking the threefold elevation of TNF-α levels in hearts from ZDF rats. CONCLUSION: LASSBio-2090 alleviates metabolic disturbance and cardiomyopathy in an obese and diabetic rat model, thus representing a novel strategy for the treatment of cardiovascular complications in obesity-associated type 2 diabetes mellitus.

Early changes in myocyte contractility and cardiac function in streptozotocin-induced type 1 diabetes in rats.

Diabetes can elicit direct deleterious effects on the myocardium, independent of coronary artery disease or hypertension. These cardiac disturbances are termed diabetic cardiomyopathy showing increased risk of heart failure with or without reduced ejection fraction. Presently, there is no specific treatment for this type of cardiomyopathy and in the case of type I diabetes, it may start in early childhood independent of glycemic control. We hypothesized that alterations in isolated myocyte contractility and cardiac function are present in the early stages of experimental diabetes in rats before overt changes in myocardium structure occur. Diabetes was induced by single-dose injection of streptozotocin (STZ) in rats with data collected from control and diabetic animals 3 weeks after injection. Left ventricle myocyte contractility was measured by single-cell length variation under electrical stimulation. Cardiac function and morphology were studied by high-resolution echocardiography with pulsed-wave tissue Doppler imaging (TDI) measurements and three-lead surface electrocardiogram. Triglycerides, cholesterol and liver enzyme levels were measured from plasma samples obtained from both groups. Myocardial collagen content and perivascular fibrosis of atria and ventricle were studied by histological analysis after picrosirius red staining. Diabetes resulted in altered contractility of isolated cardiac myocytes with increased contraction and relaxation time intervals. Echocardiography showed left atrium dilation, increased end-diastolic LV and posterior wall thickness, with reduced longitudinal systolic peak velocity (S') of the septum mitral annulus at the apical four-chamber view obtained by TDI. Triglycerides, aspartate aminotransferase and alkaline phosphatase were elevated in diabetic animals. Intertitial collagen content was higher in atria of both groups and did not differ among control and diabetic animals. Perivascular intramyocardial arterioles collagen did not differ between groups. These results suggest that alterations in cardiac function are present in the early phase in this model of diabetes type 1 and occur before overt changes in myocardium structure appear as evaluated by intersticial collagen deposition and perivascular fibrosis of intramyocardial arterioles.

Mesa 2: Insuficiencia cardíaca y diabetes mellitus tipo 2 / Table 2: heart failure and diabetes mellitus type 2

Desde que el estudio Framingham en 1974 reportó un aumento de dos a cinco veces en el riesgo de desarrollar insuficiencia cardíaca (IC) en pacientes con diabetes mellitus (DM), otros estudios observacionales confirmaron esta asociación que ha tomado gran visibilidad en los últimos años a partir de los resultados de los estudios de seguridad cardiovascular de las drogas antidiabéticas. La IC se define como un síndrome clínico que resulta del deterioro funcional o estructural del llenado ventricular o la eyección de sangre. Puede clasificarse según la fracción de eyección, la presencia de síntomas y la limitación de la actividad física. Existen distintos factores asociados a la IC en personas con DM como la edad, la antigüedad de la enfermedad, la utilización de insulina, la enfermedad coronaria, la hipertensión arterial, la enfermedad arterial periférica, el aumento de creatinina, el escaso control glucémico, la albuminuria y la obesidad. A su vez la IC se asocia a insulinorresistencia y a estados disglucémicos que se consideran de riesgo para el desarrollo de DM. En la fisiopatología están implicados el sistema nervioso simpático, el sistema renina angiotensina aldosterona, los péptidos natriuréticos, alteraciones renales, remodelación del ventrículo izquierdo, miocardiopatía diabética, neuropatía autonómica cardíaca y la inflamación. El diagnóstico de IC es clínico; los estudios complementarios orientan en el diagnóstico etiológico y son útiles en el seguimiento. El buen control glucémico es importante pero no suficiente para reducir el desarrollo de IC. Se ha descripto que algunos antidiabéticos podrían incrementar el riesgo de falla cardíaca y, por el contrario, otros tendrían un efecto beneficioso. El tratamiento de la IC no difiere de una persona sin DM. Dado que el pronóstico de la IC en los pacientes con DM es más severo, los esfuerzos deben centrarse en prevenir, diagnosticar y tratar los factores de riesgo cardiovascular para reducir el desarrollo de IC.

Since the Framingham study in 1974 reported a 2 to 5 fold increase in the risk of developing heart failure (HF) in patients with diabetes mellitus (DM), other observational studies confirmed this association that has gained great visibility in recent years from of the results of cardiovascular safety studies of antidiabetic drugs. HF is defined as a clinical syndrome that results from functional or structural deterioration of ventricular filling or blood ejection. It can be classified according to the ejection fraction, the presence of symptoms and the limitation to physical activity. There are different factors associated with HF in people with DM such as age, duration of the disease, insulin use, coronary heart disease, high blood pressure, peripheral arterial disease, increased creatinine, poor glycemic control, albuminuria and obesity. In turn, HF is associated with insulin resistance and dysglycemic states that are considered of risk for the development of DM. Pathophysiology involves the sympathetic nervous system, the renin angiotensin aldosterone system, natriuretic peptides, kidney abnormalities, left ventricular remodeling, diabetic cardiomyopathy, autonomic cardiac neuropathy, and inflammation. The diagnosis of HF is clinical, complementary studies guide the etiological diagnosis and are useful for follow-up. Good glycemic control is important but not sufficient to reduce the development of HF. It has been described that some antidiabetics could increase the risk of heart failure, while others would have a beneficial effect. The treatment of HF does not differ from a person without DM. Since the prognosis of HF in patients with DM is more severe, efforts should be focused on preventing, diagnosing and treating cardiovascular risk factors, to reduce the development of HF

A Compound Isolated from Phyllanthus tenellus Demonstrates Metabolic and Vascular Effects In Vitro.

Common chronic conditions such as metabolic syndrome and diabetes are increasingly associated to metabolic and cardiovascular complications. Although Phyllanthus tenellus leaves have been used in decoctions as a popular remedy to control blood glucose levels and hypertension, its use needs a scientific basis. This study was therefore undertaken to report a phytochemical analysis of P. tenellus leaves and to test if the main active compound has potential to simultaneously tackle several pathophysiological features of metabolic syndrome and diabetes-related metabolic and vascular disorders such as hyperglycaemia, increased platelet activation, and endothelial dysfunction. We performed a partition of the methanolic extract of P. tenellus leaves among different organic solvents followed by chromatographic separation guided by the rat liver microsomal glucose-6-phosphatase assay. Two known tannins were identified by spectroscopic methods as pinocembrin-7-O-[3″-O-galloyl-4″,6″-(S)-hexahydroxydiphenoyl]-α-D-glucose, named P7OG by us, and gemin D. The structural determination of the isolated compounds was based on spectral data. The ability of the main active component, P7OG, to inhibit human platelet aggregation and to modify vascular reactivity of rat aortic rings incubated with high glucose (D-glucose 55 mM) was then evaluated. P7OG was further able to inhibit platelet aggregation induced by adenosine 5'-diphosphate and collagen, showed vasorelaxant effects in arteries precontracted with phenylephrine, and reverted the endothelium-dependent impairment effect of high glucose in rat aortic rings. In conclusion, one tannin isolated from P. tenellus showed promising metabolic, antiaggregant, and vascular effects, which suggests the potential beneficial use of P. tenellus to tackle complex cardiometabolic diseases.