938 resultados para Cardiomyocyte Hypertrophy
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OBJECTIVE: To identify the variables that may be involved in the persistence of symptoms (functional class II, III, or IV vs. I) in patients being followed up for 30 years after surgical repair of tetralogy of Fallot. METHODS: Fifty-three patients (27 women), who underwent corrective surgery for tetralogy of Fallot between 1960 and 1970, were studied. Their ages ranged from 7 months to 26 years. At the end of follow-up, 13 patients were asymptomatic and the remaining were in functional class II (N=24), III (N=15), and IV (N=1). To differentiate asymptomatic from symptomatic patients, the following variables were analyzed: age at surgery, need for widening the pulmonary ring and trunk, need for a second (2nd OP) or 3rd operation, residual defect of the interventricular septum, residual regurgitation of the pulmonary valve, systolic gradient through the right ventricular outflow tract, right ventricular dilation or hypertrophy (RVH), cardiothoracic index (CTI), right and left ventricular ejection fraction (RVEF/LVEF), and arrhythmias. RESULTS: The univariate analysis showed an association between the presence of symptoms and the 2nd OP (P=0.03), an increase in the CTI (P=0.0001), moderate to severe RVH (P=0.002), and dilation (P=0.0003). In the logistic regression model, the combination of the 2nd OP (P=0.008), the RVH (P=0.002), and the reduction in RVEF (P=0.01) determined the presence of symptoms. CONCLUSION: Despite the surgical treatment, right ventricular remodeling and performance were the major determinants in the late follow-up of tetralogy of Fallot.
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OBJECTIVE: To identify the electrocardiographic changes and their associations with metabolic and electrolytic changes in female alcoholics. METHODS: The study comprised 44 female alcoholics with no apparent physical disorder. They underwent the following examinations: conventional electrocardiography; serologic tests for syphilis, Chagas' disease, and hepatitis B and C viruses; urinary pregnancy testing; hematimetric analysis; biochemical measurements of albumin, fibrinogen, fasting and postprandial glycemias, lipids, hepatic enzymes, and markers for tissue necrosis and inflammation. RESULTS: Some type of electrocardiographic change was identified in 33 (75%) patients. In 17 (38.6%) patients, more than one of the following changes were present: prolonged QTc interval in 24 (54.5%), change in ventricular repolarization in 11(25%), left ventricular hypertrophy in 6 (13.6%), sinus bradycardia in 4 (9.1%), sinus tachycardia in 3 (6.8%), and conduction disorder in 3 (6.8%). The patients had elevated mean serum levels of creatine phosphokinase, aspartate aminotransferases, and gamma glutamyl transferase, as well as hypocalcemia and low levels of total cholesterol and LDL-cholesterol. The patients with altered electrocardiograms had a more elevated age, a lower alcohol consumption, hypopotassemia, and significantly elevated levels of triglycerides, postprandial glucose, sodium and gamma glutamyl transferase than those with normal electrocardiograms. The opposite occurred with fasting glycemia, magnesium, and alanine aminotransferase. CONCLUSION: The electrocardiographic changes found were prolonged QTc interval, change in ventricular repolarization, and left ventricular hypertrophy. Patients with normal and abnormal electrocardiograms had different metabolic and electrolytic changes.
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OBJECTIVE: To characterize the follow-up of an experimental model of left ventricular hypertrophy (LVH) induced by supravalvular ascending aortic stenosis in young rats. METHODS: Wistar rats were submitted to thoracotomy and aortic stenosis was created by placing a clip on the ascending aorta (AoS group, n=12). Age-matched control animals underwent a sham operation (C group, n=12). Cardiac function was analysed by echocardiograms performed 6, 12, and 21 weeks after aortic banding. Myocardial morphological features and myocardial hydroxyproline concentration (HOP) were evaluated 2, 6, 12, and 21 weeks after surgery in additional animals. RESULTS: Aortic banding promoted early concentric LVH and a progressive increase in HOP. Under light microscopy, we observed myocyte hypertrophy and wall thickening of the intramural branches of the coronary arteries due to medial hypertrophy. Cardiac function was supranormal after 6 weeks (percentage of fractional shortening - EAo6: 70.3±10.8; C6: 61.3±5.4; p<0.05), and depressed in the last period. Diastolic dysfunction was detected after 12 weeks (ratio of early-to-late filling velocity - EAo12: 4.20±3.25; C12: 1.61±0.16; p<0.05). CONCLUSION: Ascending aortic stenosis promotes concentric LVH with myocardial fibrosis and minimal histological changes. According to the period of evaluation, cardiac function may be improved, normal, or depressed. The model is suitable and useful for studies on pathophysiology and treatment of the different phases of cardiac hypertrophy.
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La enfermedad de Chagas, causada por Trypanosoma cruzi, constituye la principal miocarditis infecciosa a nivel mundial. Crecientes evidencias revelan que la respuesta inmune innata tendría un rol determinante en la fisiopatología de las enfermedades cardiovasculares. La inmunidad innata es la primera línea de defensa, no específica, preprogramada para combatir agentes infecciosos. Este sistema censa la presencia de antígenos extraños a través de los receptores tipo toll (TLR) produciendo citoquinas y activando mecanismos microbicidas. Sin embargo, los TLRs también se hayan distribuidos en las células parenquimales no inmunes, jugando un importante rol tanto en la defensa como en la homeostasis de cada tejido. Durante la etapa aguda de la infección, el T. cruzi invade y se replica dentro de una amplia variedad de células y tejidos. Pero posteriormente, los parásitos son efectivamente eliminados de la mayoría de los tejidos persistiendo durante toda la vida en las células del músculo cardíaco y esquelético de los pacientes infectados. Debido a que el mantenimiento de la célula cardíaca infectada es crítica para la patogénesis de la enfermedad, los mecanismos que participan en la sobrevida de los cardiomiocitos están siendo foco de nuestro estudio. Hemos demostrado, que la infección ejerce efectos antiapoptóticos sobre células cardíacas aisladas. Nuestra hipótesis es que la inmunidad innata cardíaca estaría involucrada en el mantenimiento de la sobrevida de los miocitos así como en la defensa contra el parásito. Objetivo general: determinar la participación de la respuesta inmune innata cardíaca en el desarrollo de la enfermedad de Chagas experimental murina. Objetivos específicos: 1) Analizar el compromiso de TLRs en la respuesta anti-apoptótica y de autofagia de cardiomiocitos aislados de ratones salvajes y de ratones deficientes en TLR4, TLR2 y en MyD88, molécula adaptadora de la señalización por TLRs, sometidos a la infección con el parásito. 2) Determinar la importancia de la actividad cisteín proteasa parasitaria en el grado de infectividad y la sobrevida de cultivos primarios de ratones salvajes infectados con parásitos transgénicos que poseen disminuída o nula actividad cisteín proteasa. 3) Establecer la cinética de expresión de TLR2/TLR6, TLR4 y TLR9, factores antiapoptóticos (Bcl-2, Bcl-xL, etc.), daño cardíaco y la carga parasitaria en el tejido cardíaco de ratones infectados salvajes y/o deficientes antes mencionados. Materiales y Métodos: Los animales serán infectados i.p. con 5x103 parásitos y se determinará la cinética de expresión de los mediadores mencionados por western blot e inmunofluorescencia, la carga parasitaria será determinada por qRT-PCR. Como controles se procesarán animales inyectados con solución salina. En cultivos primarios de cardiomiocitos de ratones neonatos salvajes y deficientes infectados se estudiará la carga parasitaria, la activación de los mecanismos microbicidas (producción de óxido nítrico, metabolitos reactivos del oxígeno y del nitrógeno, ciclooxigenasa, etc.), producción de citoquinas y expresión de moléculas anti-apoptóticas (Bcl-2, Bcl-xL, Bax, etc.). Se explorará la tasa de apoptosis en cultivos deprivados de suero. La autofagia se analizará por microscopia electrónica. Cultivos controles serán mantenidos en medio o tratados con ligandos de los diferentes TLRs. Resultados preliminares sugieren que tanto TLR2 como Bcl-2 se incrementan en tejido cardíaco infectado. Esto nos lleva a profundizar en los mecanismos observados en cultivos y estudiarlos en un modelo in vivo, analizando la posible importancia que tiene la inmunidad innata cardíaca en el control del establecimiento de la infección. La comprensión de los mecanismos que mantienen la sobrevida de los cardiomiocitos y su respuesta a la infección es importante ya que el conocimiento de las bases moleculares es fundamental para el desarrollo de nuevos agentes quimioterapéuticos. Chagas disease is endemic in Central and South America and causes the most common myocarditis worldwide. We have previously reported that the cardiotrophic parasite Trypanosoma cruzi, its etiological agent, protects cardiomyocytes against apoptosis induced by growth factor deprivation activating the PI3K/Akt and MEK1/ERK signaling pathways. Recent studies have shown that local innate immunity plays a key role in initiating and coordinating homeostatic as well as defense responses in the heart. One of the mechanisms by which the innate immune system senses the presence of foreign antigens is through TLRs. The stimulation of these receptors leads to the activation and nuclear translocation of NF-kB transcription factor and the production of cytokines. Proinflammatory cytokines, in turn, appear to play a central role in the orchestration and timing of the intrinsic cardiac stress response providing, under different situations, instantaneous anti-apoptotic cytoprotective signals, which allow tissue repair and/or remodeling. The aim of the present project is to study the cardiomyocyte innate immune responses to T. cruzi infection and its role in target cell protection from apoptosis. Specific objectives: 1) Study the mechanism triggered by TLR in the anti-apoptotic response and parasite load of infected cardiomyocyte primary cultures from wild type and mice deficient in TLR2, TLR4 or MyD88. 2) Determine the effect of parasite cisteín protease activity on primary cultures from wild type mice. 3) Determine the TLR signaling-involvement in parasite load and survival indicators in deficient mice. Preliminary results showed us that cardiac-TLR2 may be involved in the anti-apoptotic effect elicited by the parasite and prompted us to establish the mechanisms triggered by the innate immunity that mediate parasite persistence within the host cell.
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Background: Patients with diabetes are in extract higher risk for fatal cardiovascular events. Objective: To evaluate major predictors of mortality in subjects with type 2 diabetes. Methods: A cohort of 323 individuals with type 2 diabetes from several regions of Brazil was followed for a long period. Baseline electrocardiograms, clinical and laboratory data obtained were used to determine hazard ratios (HR) and confidence interval (CI) related to cardiovascular and total mortality. Results: After 9.2 years of follow-up (median), 33 subjects died (17 from cardiovascular causes). Cardiovascular mortality was associated with male gender; smoking; prior myocardial infarction; long QTc interval; left ventricular hypertrophy; and eGFR <60 mL/min. These factors, in addition to obesity, were predictors of total mortality. Cardiovascular mortality was adjusted for age and gender, but remained associated with: smoking (HR = 3.8; 95% CI 1.3-11.8; p = 0.019); prior myocardial infarction (HR = 8.5; 95% CI 1.8-39.9; p = 0.007); eGFR < 60 mL/min (HR = 9.5; 95% CI 2.7-33.7; p = 0.001); long QTc interval (HR = 5.1; 95% CI 1.7-15.2; p = 0.004); and left ventricular hypertrophy (HR = 3.5; 95% CI 1.3-9.7; p = 0.002). Total mortality was associated with obesity (HR = 2.3; 95% CI 1.1-5.1; p = 0.030); smoking (HR = 2.5; 95% CI 1.0-6.1; p = 0.046); prior myocardial infarction (HR = 3.1; 95% CI 1.4-6.1; p = 0.005), and long QTc interval (HR = 3.1; 95% CI 1.4-6.1; p = 0.017). Conclusions: Biomarkers of simple measurement, particularly those related to target-organ lesions, were predictors of mortality in subjects with type 2 diabetes.
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Background: The importance of measuring blood pressure before morning micturition and in the afternoon, while working, is yet to be established in relation to the accuracy of home blood pressure monitoring (HBPM). Objective: To compare two HBPM protocols, considering 24-hour ambulatory blood pressure monitoring (wakefulness ABPM) as gold-standard and measurements taken before morning micturition (BM) and in the afternoon (AM), for the best diagnosis of systemic arterial hypertension (SAH), and their association with prognostic markers. Methods: After undergoing 24-hour wakefulness ABPM, 158 participants (84 women) were randomized for 3- or 5-day HBPM. Two variations of the 3-day protocol were considered: with measurements taken before morning micturition and in the afternoon (BM+AM); and with post-morning-micturition and evening measurements (PM+EM). All patients underwent echocardiography (for left ventricular hypertrophy - LVH) and urinary albumin measurement (for microalbuminuria - MAU). Result: Kappa statistic for the diagnosis of SAH between wakefulness-ABPM and standard 3-day HBPM, 3-day HBPM (BM+AM) and (PM+EM), and 5-day HBPM were 0.660, 0.638, 0.348 and 0.387, respectively. The values of sensitivity of (BM+AM) versus (PM+EM) were 82.6% × 71%, respectively, and of specificity, 84.8% × 74%, respectively. The positive and negative predictive values were 69.1% × 40% and 92.2% × 91.2%, respectively. The comparisons of intraclass correlations for the diagnosis of LVH and MAU between (BM+AM) and (PM+EM) were 0.782 × 0.474 and 0.511 × 0.276, respectively. Conclusions: The 3 day-HBPM protocol including measurements taken before morning micturition and during work in the afternoon showed the best agreement with SAH diagnosis and the best association with prognostic markers.
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Background: Echocardiography, though non-invasive and having relatively low-cost, presents issues of variability which can limit its use in epidemiological studies. Objective: To evaluate left ventricular mass reproducibility when assessed at acquisition (online) compared to when assessed at a reading center after electronic transmission (offline) and also when assessed by different readers at the reading center. Methods: Echocardiographers from the 6 ELSA-Brasil study investigation centers measured the left ventricular mass online during the acquisition from 124 studies before transmitting to the reading center, where studies were read according to the study protocol. Half of these studies were blindly read by a second reader in the reading center. Results: From the 124 echocardiograms, 5 (4%) were considered not measurable. Among the remaining 119, 72 (61%) were women, mean age was 50.2 ± 7.0 years and 2 had structural myocardial abnormalities. Images were considered to be optimal/ good by the reading center for 110 (92.4%) cases. No significant difference existed between online and offline measurements (1,29 g, CI 95% −3.60-6.19), and the intraclass correlation coefficient between them was 0.79 (CI 95% 0.71-0.85). For images read by two readers, the intraclass correlation coefficient was 0.86 (CI 95% 0.78-0.91). Conclusion: There were no significant drifts between online and offline left ventricular mass measurements, and reproducibility was similar to that described in previous studies. Central quantitative assessment of echocardiographic studies in reading centers, as performed in the ELSA-Brasil study, is feasible and useful in clinical and epidemiological studies performed in our setting.
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Introduction: Obesity-related comorbidities are present in young obese children, providing a platform for early adult cardiovascular disorders. Objectives: To compare and correlate markers of adiposity to metabolic disturbances, vascular and cardiac morphology in a European pediatric obese cohort. Methods: We carried out an observational and transversal analysis in a cohort consisting of 121 obese children of both sexes, between the ages of 6 and 17 years. The control group consisted of 40 children with normal body mass index within the same age range. Markers of adiposity, plasma lipids and lipoproteins, homeostasis model assessment-insulin resistance, common carotid artery intima-media thickness and left ventricular diameters were analyzed. Results: There were statistically significant differences between the control and obese groups for the variables analyzed, all higher in the obese group, except for age, high-density lipoprotein cholesterol and adiponectin, higher in the control group. In the obese group, body mass index was directly correlated to left ventricular mass (r=0.542; p=0.001), the homeostasis model assessment-insulin resistance (r=0.378; p=<0.001) and mean common carotid artery intima-media thickness (r=0.378; p=<0.001). In that same group, insulin resistance was present in 38.1%, 12.5% had a combined dyslipidemic pattern, and eccentric hypertrophy was the most common left ventricular geometric pattern. Conclusions: These results suggest that these markers may be used in clinical practice to stratify cardiovascular risk, as well as to assess the impact of weight control programs.
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Abstract Background: Although the beneficial effects of resistance training (RT) on the cardiovascular system are well established, few studies have investigated the effects of the chronic growth hormone (GH) administration on cardiac remodeling during an RT program. Objective: To evaluate the effects of GH on the morphological features of cardiac remodeling and Ca2+ transport gene expression in rats submitted to RT. Methods: Male Wistar rats were divided into 4 groups (n = 7 per group): control (CT), GH, RT and RT with GH (RTGH). The dose of GH was 0.2 IU/kg every other day for 30 days. The RT model used was the vertical jump in water (4 sets of 10 jumps, 3 bouts/wk) for 30 consecutive days. After the experimental period, the following variables were analyzed: final body weight (FBW), left ventricular weight (LVW), LVW/FBW ratio, cardiomyocyte cross-sectional area (CSA), collagen fraction, creatine kinase muscle-brain fraction (CK-MB) and gene expressions of SERCA2a, phospholamban (PLB) and ryanodine (RyR). Results: There was no significant (p > 0.05) difference among groups for FBW, LVW, LVW/FBW ratio, cardiomyocyte CSA, and SERCA2a, PLB and RyR gene expressions. The RT group showed a significant (p < 0.05) increase in collagen fraction compared to the other groups. Additionally, the trained groups (RT and RTGH) had greater CK-MB levels compared to the untrained groups (CT and GH). Conclusion: GH may attenuate the negative effects of RT on cardiac remodeling by counteracting the increased collagen synthesis, without affecting the gene expression that regulates cardiac Ca2+ transport.
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Abstract Background: Tobacco smoke exposure is an important risk factor for cardiac remodeling. Under this condition, inflammation, oxidative stress, energy metabolism abnormalities, apoptosis, and hypertrophy are present. Pentoxifylline has anti‑inflammatory, anti-apoptotic, anti-thrombotic and anti-proliferative properties. Objective: The present study tested the hypothesis that pentoxifylline would attenuate cardiac remodeling induced by smoking. Methods: Wistar rats were distributed in four groups: Control (C), Pentoxifylline (PX), Tobacco Smoke (TS), and PX-TS. After two months, echocardiography, invasive blood pressure measurement, biochemical, and histological studies were performed. The groups were compared by two-way ANOVA with a significance level of 5%. Results: TS increased left atrium diameter and area, which was attenuated by PX. In the isolated heart study, TS lowered the positive derivate (+dp/dt), and this was attenuated by PX. The antioxidants enzyme superoxide dismutase and glutathione peroxidase were decreased in the TS group; PX recovered these activities. TS increased lactate dehydrogenase (LDH) and decreased 3-hydroxyacyl Coenzyme A dehydrogenases (OH-DHA) and citrate synthase (CS). PX attenuated LDH, 3-OH-DHA and CS alterations in TS-PX group. TS increased IL-10, ICAM-1, and caspase-3. PX did not influence these variables. Conclusion: TS induced cardiac remodeling, associated with increased inflammation, oxidative stress, apoptosis, and changed energy metabolism. PX attenuated cardiac remodeling by reducing oxidative stress and improving cardiac bioenergetics, but did not act upon cardiac cytokines and apoptosis.
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Definite hyperplasia of cells occurs in the skin lesions of the infectious myxoma of rabbits, more visible in such stages in which the intercellular basophilic substance is rather scanty (fig. 2). The increase in number of cells is the result of simplified forms of mitosis (modified type of mitosis, pseudoamitosis) which might readily be mistaken for amitosis in their final stages. Budding (figs. 20, 28, 29, 30) as well as constriction of the nucleus (figs. 18, 31, 32), and the formation of giant-cells (figs. 33, 34) are not rare. During the entire process the nuclear membrane does not desintegrate as in typical mitosis. Division of the cytoplasm following division of the nucleus has been demonstrated (fig. 17). Typical mitosis is practically absent. The cells which undergo hyperplasia present remarkable changes in their dimension, shape, and structure. The nucleus and cell-body are considerably enlarged (figs. 6, 7, 8). The shape of the nucleus is modified (figs. 8, 10, 15). Hypertrophy of nuclein, either as an intranuclear network (spireme?, figs. 9, 23), or in the form conspicuous, deeply staining masses which appear not to be homogeneous but to be composed of small particles closely clumped ("mulberries"?, figs. 12, 13, 14, 25, 26) occurs in most cells. While some of these pictures are probably related to necrosis of the cells as started by most of the previous workers, it is lekely that some of them may represent developmental stages of the modified mitosis (pseudoamitosis) here reported. In fact, fine cytological details not ordinarily preserved in necrotic cells (figs. 35, 36, 37) may be demonstrated in the socalled myxoma-cells subtted to approved cytological methods of study (fixation in B-15 and P. F. A.-3, staining in iron-hematoxylin).
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A second species of monkey Plasmodium of the New World is described from the howler monkey Alouatta`fusca GEOFFROY, 1812, captured in Itapecirica, São Paulo, Brazil. The new species differs from Plasmodium brasilianum GONDER et VON BERENBERG-GOSSLER, 1909 by following characters: 1st. Almost constant presence in the blood cells of granulations of the same type as SCHÜFFNER dots. 2nd. Considerable hypertrophy of the parasitised cells. 3rd. Greater number of merozoites after schizogony with an habitual minimum of 16 elements in contrast with the maximum of 16 in Plasmodium brasilianum. 4th. Extreme rarity of band forms. This morphology strongly suggests an infection of the benignan tertian type. To this new species the name of Plasmodium simium, sp.n. is proposed.
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The megaesophagus and megacolon endemic in South America are related , to Chagas' disease. These mega conditions are found in patients with chronic Chagas's infection, when the parasite is not demonstrable in the lesions. These are characterized by depopulation of parasympathetic ganglion cells, dilation and hypertrophy of the viscera. In the experiments described here we deminstrate a selective affinity and adherence of Trypanosoma cruzi-immune lymphocytes to myenteric, parasympathetic ganglion cells, leading to neuronolysis. None of these features are observed when non-immune lymphocytes from control rabbits are used, or when the immune lymphocytes are allowed to react with CNS neurons. This demonstration is an indication of the high degree of specificity of the destruction of parasympathetic neurons in Chagas' disease. We postulate that the T. cruzi-immune lymphocyte rejection of parasympathetic neurons, but not of CNS neurons, might be related to recognition of a cross-reacting antigenic determinant secreted only by the target neurons. In favor of this interpretation is the observation of lymphocytic infiltrates and parasympathetic ganglion cell destruction in chronic Chagas' infection in the absence of encephalitis.
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OBJECTIVE. The purpose of this study was to evaluate the prevalence of mesenteric venous thrombosis (MVT) in the Swiss Inflammatory Bowel Disease Cohort Study and to correlate MVT with clinical outcome. MATERIALS AND METHODS. Abdominal portal phase CT was used to examine patients with inflammatory bowel disease (IBD). Two experienced abdominal radiologists retrospectively analyzed the images, focusing on the superior and inferior mesenteric vein branches and looking for signs of acute or chronic thrombosis. The location of abnormalities was registered. The presence of MVT was correlated with IBD-related radiologic signs and complications. RESULTS. The cases of 160 patients with IBD (89 women, 71 men; Crohn disease [CD], 121 patients; ulcerative colitis [UC], 39 patients; median age at diagnosis, 27 years for patients with CD, 32 years for patients with UC) were analyzed. MVT was detected in 43 patients with IBD (26.8%). One of these patients had acute MVT; 38, chronic MVT; and four, both. The prevalence of MVT did not differ between CD (35/121 [28.9%]) and UC (8/39 [20.5%]) (p = 0.303). The location of thrombosis was different between CD and UC (CD, jejunal or ileal veins only [p = 0.005]; UC, rectocolic veins only [p = 0.001]). Almost all (41/43) cases of thrombosis were peripheral. MVT in CD patients was more frequently associated with bowel wall thickening (p = 0.013), mesenteric fat hypertrophy (p = 0.005), ascites (p = 0.002), and mesenteric lymph node enlargement (p = 0.036) and was associated with higher rate of bowel stenosis (p < 0.001) and more intestinal IBD-related surgery (p = 0.016) in the outcome. Statistical analyses for patients with UC were not relevant because of the limited population (n = 8). CONCLUSION. MVT is frequently found in patients with IBD. Among patients with CD, MVT is associated with bowel stenosis and CD-related intestinal surgery.
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BACKGROUND: Dilated cardiomyopathy (DCM) is a leading cause of chronic morbidity and mortality in muscular dystrophy (MD) patients. Current pharmacological treatments are not yet able to counteract chronic myocardial wastage, thus novel therapies are being intensely explored. MicroRNAs have been implicated as fine regulators of cardiomyopathic progression. Previously, miR-669a downregulation has been linked to the severe DCM progression displayed by Sgcb-null dystrophic mice. However, the impact of long-term overexpression of miR-669a on muscle structure and functionality of the dystrophic heart is yet unknown. METHODS AND RESULTS: Here, we demonstrate that intraventricular delivery of adeno-associated viral (AAV) vectors induces long-term (18 months) miR-669a overexpression and improves survival of Sgcb-null mice. Treated hearts display significant decrease in hypertrophic remodeling, fibrosis, and cardiomyocyte apoptosis. Moreover, miR-669a treatment increases sarcomere organization, reduces ventricular atrial natriuretic peptide (ANP) levels, and ameliorates gene/miRNA profile of DCM markers. Furthermore, long-term miR-669a overexpression significantly reduces adverse remodeling and enhances systolic fractional shortening of the left ventricle in treated dystrophic mice, without significant detrimental consequences on skeletal muscle wastage. CONCLUSIONS: Our findings provide the first evidence of long-term beneficial impact of AAV-mediated miRNA therapy in a transgenic model of severe, chronic MD-associated DCM.