Desafios e Aplicações dos Testes Genéticos na Cardiomiopatia Dilatada: Genótipo, Fenótipo e Implicações Clínicas / Challenges and Applications of Genetic Testing in Dilated Cardiomyopathy: Genotype, Phenotype and Clinical Implications

Resumo Os testes genéticos para cardiomiopatia dilatada (CMD) apresentam uma positividade de até 40%, mas há uma grande heterogeneidade genética e outros desafios decorrentes de expressividade variável e penetrância incompleta. O heredograma é fundamental para diferenciar os casos de CMD esporádica e familiar, por meio da avaliação do histórico familiar. A CMD familiar apresenta um rendimento maior nos testes genéticos, mas a CMD esporádica não exclui a possibilidade de causa genética. Alguns genes têm fenótipos específicos, sendo o gene da Lamina ( LMNA ) o mais fortemente associado a um fenótipo de arritmias malignas e quadros de insuficiência cardíaca (IC) avançada. A presença de uma variante genética causal também pode ajudar na avaliação prognóstica, identificando quadros mais graves e com menores taxas de remodelamento reverso em comparação com indivíduos com genótipo negativo. As diretrizes atuais recomendam a avaliação e aconselhamento genético em indivíduos com CMD, além do rastreamento em cascata nos familiares de primeiro grau nos casos em que há uma ou mais variantes identificadas, sendo uma oportunidade para o diagnóstico e tratamento precoces. Familiares com genótipo positivo e fenótipo negativo são candidatos à avaliação seriada, com periodicidade que varia conforme a idade. O genótipo também auxilia na indicação individualizada de cardiodesfibrilador implantável e em recomendações quanto à atividade física e planejamento familiar. Estudos em curso esclarecem progressivamente os detalhes das relações genótipo/fenótipo de um grande número de variantes e fazem com que a genética molecular esteja cada vez mais presente na prática clínica.

Abstract Genetic tests for dilated cardiomyopathy (DCM) have a diagnostic yield of up to 40%, but there is significant genetic heterogeneity and other challenges, such as variable expressivity and incomplete penetrance. Pedigree analysis is essential for distinguishing between sporadic and familial DCM cases by assessing family history. Familial DCM yields higher results in genetic testing, but sporadic DCM does not rule out the possibility of a genetic cause. Some genes have specific phenotypes, with the Lamin gene ( LMNA ) being associated with a phenotype of malignant arrhythmias and advanced heart failure (HF). The presence of a causal genetic variant can also aid in prognostic evaluation, identifying more severe cases with lower rates of reverse remodeling (RR) compared to individuals with a negative genotype. Current guidelines recommend genetic evaluation and counseling for individuals with DCM, along with cascade screening in first-degree relatives in cases where one or more variants are identified, offering an opportunity for early diagnosis and treatment. Relatives with a positive genotype and negative phenotype are candidates for serial evaluation, with frequency varying by age. Genotype also assists in individualized recommendations for implantable cardioverter-defibrillator (ICD) placement and advice regarding physical activity and family planning. Ongoing studies are progressively elucidating the details of genotype/phenotype relationships for a large number of variants, making molecular genetics increasingly integrated into clinical practice.

Rastreamento para Hipercolesterolemia Familiar em Pequenos Municípios: A Experiência do Programa HipercolBrasil em 11 Municípios Brasileiros / Screening for Familial Hypercholesterolemia in Small Towns: Experience from 11 Brazilian Towns in the Hipercolbrasil Program

Resumo Fundamento A hipercolesterolemia familiar (HF) é uma doença genética dominante que se caracteriza por níveis sanguíneos elevados de colesterol de lipoproteína de baixa densidade (LDL-C), e está associada à ocorrência de doença cardiovascular precoce. No Brasil, o HipercolBrasil, que é atualmente o maior programa de rastreamento em cascata para HF, já identificou mais de 2.000 indivíduos com variantes genéticas causadoras de HF. A abordagem padrão baseia-se no rastreamento em cascata de casos índices referidos, indivíduos com hipercolesterolemia e suspeita clínica de HF. Objetivos Realizar rastreamento direcionado de 11 pequenos municípios brasileiros com suspeita de alta prevalência de indivíduos com HF. Métodos A seleção dos municípios ocorreu de 3 maneiras: 1) municípios em que houve suspeita de efeito fundador (4 municípios); 2) municípios em uma região com altas taxas de infarto do miocárdio precoce, conforme descrito pelo banco de dados do Sistema Único de Saúde (2 municípios); e 3) municípios geograficamente próximos a outros municípios com alta prevalência de indivíduos com HF (5 municípios). A significância estatística foi considerada como valor p < 0,05. Resultados Foram incluídos 105 casos índices e 409 familiares de primeiro grau. O rendimento dessa abordagem foi de 4,67 familiares por caso índice, o qual é significativamente melhor (p < 0,0001) do que a taxa geral do HipercolBrasil (1,59). Identificamos 36 CIs com variante patogênica ou provavelmente patogênica para HF e 240 familiares de primeiro grau afetados. Conclusão: Nossos dados sugerem que, uma vez detectadas, regiões geográficas específicas justificam uma abordagem direcionada para a identificação de aglomerações de indivíduos com HF.

Abstract Background Familial hypercholesterolemia (FH) is a genetic disease characterized by elevated serum levels of low-density lipoprotein cholesterol (LDL-C), and it is associated with the occurrence of early cardiovascular disease. In Brazil, HipercolBrasil, which is currently the largest FH cascade screening program, has already identified more than 2000 individuals with causal genetic variants for FH. The standard approach is based on cascade screening of referred index cases, individuals with hypercholesterolemia and clinical suspicion of FH. Objectives To perform targeted screening of 11 small Brazilian cities with a suspected high prevalence of people with FH. Methods The selection of cities occurred in 3 ways: 1) cities in which a founder effect was suspected (4 cities); 2) cities in a region with high rates of early myocardial infarction as described by the National Health System database (2 cities); and 3) cities that are geographically close to other cities with a high prevalence of individuals with FH (5 cities). Statistical significance was considered as p value < 0.05. Results One hundred and five index cases and 409 first-degree relatives were enrolled. The yield of such approach of 4.67 relatives per index case was significantly better (p < 0.0001) than the general HipercolBrasil rate (1.59). We identified 36 IC with a pathogenic or likely pathogenic variant for FH and 240 affected first-degree relatives. Conclusion Our data suggest that, once detected, specific geographical regions warrant a target approach for identification of clusters of individuals with FH.

Perfil Clínico, Laboratorial e de Métodos de Imagem na Amiloidose Sistêmica em um Centro de Referência Cardiológico Brasileiro / Clinical, Laboratory, and Imaging Profile in Patients with Systemic Amyloidosis in a Brazilian Cardiology Referral Center

Resumo Fundamento Amiloidose sistêmica é uma doença com manifestações clínicas diversas. O diagnóstico envolve suspeita clínica, aliada a métodos complementares. Objetivo Descrever o perfil clínico, laboratorial, eletrocardiográfico e de imagem no acometimento cardíaco da amiloidose sistêmica. Métodos Estudo de uma amostra de conveniência, analisando dados clínicos, laboratoriais, eletrocardiográficos, ecocardiográficos, medicina nuclear e ressonância magnética. Considerou-se significância estatística quando p < 0,05. Resultados Avaliaram-se 105 pacientes (com mediana de idade de 66 anos), sendo 62 homens, dos quais 83 indivíduos apresentavam amiloidose por transtirretina (ATTR) e 22 amiloidose por cadeia leve (AL). Na ATTR, 68,7% eram de caráter hereditário (ATTRh) e 31,3% do tipo selvagem (ATTRw). As mutações mais prevalentes foram Val142Ile (45,6%) e Val50Met (40,3%). O tempo de início dos sintomas ao diagnóstico foi 0,54 e 2,15 anos nas formas AL e ATTR (p < 0,001), respectivamente. O acometimento cardíaco foi observado em 77,9% dos ATTR e 90,9% dos AL. Observaram-se alterações de condução atrioventricular em 20% e intraventricular em 27,6% dos pacientes, sendo 33,7 % na ATTR e 4,5% das AL (p = 0,006). A forma ATTRw apresentou mais arritmias atriais que os ATTRh (61,5% x 22,8%; p = 0,001). Ao ecocardiograma a mediana da espessura do septo na ATTRw x ATTRh x AL foi de 15 mm x 12 mm x 11 mm (p = 0,193). Observou-se BNP elevado em 89,5% dos indivíduos (mediana 249 ng/mL, IQR 597,7) e elevação da troponina em 43,2%. Conclusão Foi possível caracterizar, em nosso meio, o acometimento cardíaco na amiloidose sistêmica, em seus diferentes subtipos, através da história clínica e dos métodos diagnósticos descritos.

Abstract Background Systemic amyloidosis is a disease with heterogeneous clinical manifestations. Diagnosis depends on clinical suspicion combined with specific complementary methods. Objective To describe the clinical, laboratory, electrocardiographic, and imaging profile in patients with systemic amyloidosis with cardiac involvement. Methods This study was conducted with a convenience sample, analyzing clinical, laboratory, electrocardiographic, echocardiographic, nuclear medicine, and magnetic resonance data. Statistical significance was set at p < 0.05. Results A total of 105 patients were evaluated (median age of 66 years), 62 of whom were male. Of all patients, 83 had transthyretin (ATTR) amyloidosis, and 22 had light chain (AL) amyloidosis. With respect to ATTR cases, 68.7% were the hereditary form (ATTRh), and 31.3% were wild type (ATTRw). The most prevalent mutations were Val142Ile (45.6%) and Val50Met (40.3%). Time from onset of symptoms to diagnosis was 0.54 and 2.15 years, in the AL and ATTR forms, respectively (p < 0.001). Cardiac involvement was observed in 77.9% of patients with ATTR and in 90.9% of those with AL. Alterations were observed in atrioventricular and intraventricular conduction in 20% and 27.6% of patients, respectively, with 33.7% in ATTR and 4.5% in AL (p = 0.006). In the ATTRw form, there were more atrial arrhythmias than in ATTRh (61.5% versus 22.8%; p = 0.001). On echocardiogram, median septum thickness in ATTRw, ATTRh, and AL was 15 mm, 12 mm, and 11 mm, respectively (p = 0.193). Elevated BNP was observed in 89.5% of patients (median 249, ICR 597.7), and elevated troponin was observed in 43.2%. Conclusion In this setting, it was possible to characterize cardiac involvement in systemic amyloidosis in its different subtypes by means of clinical history and the diagnostic methods described.

Gene expression profile in experimental frozen-thawed ovarian grafts treated with scaffold-base delivery of adipose tissue-derived stem cells

Abstract Purpose: Gelfoam scaffold is a feasible and safe non-invasive technique for Adipose tissue-derived Stem Cell (ASC)-delivery in the treatment of frozen-thawed ovarian autografts. This study seeks to analyze the genes expression profile of rat frozen-thawed ovarian autografts treated with scaffold-based delivery of adipose tissue-derived stem cells. Methods: Eighteen adult Wistar rats were distributed into three groups: Control (frozen-thawed only); Group 1 (Gl) and Group 2 (G2) (frozen-thawed ovaries treated with culture medium or ASC, respectively). Both treatments were performed immediately after autologous retroperitoneal transplant with scaffold-based delivery. The ovarian grafts were retrieved 30 days after transplantation. Quantitative gene expression (qPCR) for apoptosis, angiogenesis, and inflammatory cytokines (84 genes in each pathway) were evaluated by RT-PCR. Graft morphology (HE), apoptosis (cleaved-caspase-3), neoangiogenesis (VEGF), and cellular proliferation (Ki-67) were assessed. Results: In grafts treated with ASC, the apoptosis pathway showed the highest number of genes over-regulated — 49 genes — compared to inflammation cytokines and angiogenesis pathway — 36 and 23 genes respectively, compared to grafts treated with culture medium. Serpinb5 family was highlighted in the angiogenesis pathway and Cxcl6 in the inflammation cytokines pathway. In the apoptosis pathway, the most over-regulated gene was Cap-sasel4. ASC treatment promoted the reduction of cleaved caspase-3 in the theca internal layer and increased cell proliferation by Ki-67 in the granulosa layer without altering VEGF. A mild inflammatory infiltrate was observed in both groups. Conclusion: ASC therapy in rat frozen-thawed ovarian autografts promoted an abundance of genes involved with apoptosis and inflammatory cytokines without compromising the ovary graft morphology and viability for short time. Further studies are necessary to evaluate the repercussion of apoptosis and inflammation on the graft in the long term. HIGHLIGHTS The scaffold-based delivery therapy with adipose tissue-derived stem cells in the rat ovarian autografts seems to be the best option when compared to direct injection or systemic route. Ovarian grafts treated with adipose tissue-derived stem cells showed the highest number of genes over-regulated in the apoptosis pathway, compared to inflammation cytokines and angiogenesis pathway. Capsase14 was the most over-regulated gene in the apoptosis pathway. The treatment with adipose tissue-derived stem cells in ovarian grafts treated didn't compromise the ovary graft morphology and viability for short time.

Polymorphisms of the renin-angiotensin system are not associated with overweight and obesity in a general adult population

ABSTRACT Objective The increased prevalence of obesity and associated comorbidities, such as cardiovascular and metabolic diseases, has gained attention worldwide, and the renin-angiotensin system (RAS) has been pointed out as a possible link. Thus, the present study aimed to verify the possible association between angiotensinogen (AGT) or angiotensin-converting enzyme (ACE) polymorphisms with overweight and obesity in adults. Subjects and methods The present investigation was a population-based cross-sectional study including 1,567 individuals from an urban area in Brazil. Anthropometric, clinical and biochemical parameters were evaluated, and all individuals were genotyped for the ACE I/D and AGT M/T polymorphisms. Results The prevalence of overweight was higher among men, whereas obesity was more prevalent among women. However, the frequency of ACE or AGT polymorphisms was similar among body mass index (BMI) categories. In addition, the mean age-adjusted BMI averages did not change significantly for ACE or AGT polymorphisms, regardless of sex or BMI category. The age-adjusted BMI average for the combination of ACE and AGT genotypes evidenced no significant differences regardless of sex or BMI categories. Results were similar when BMI was replaced by waist circumference (WC). Conclusions We were not able to find any associations between BMI and WC (overweight/obesity) and ACE and AGT polymorphisms, indicating that the RAS system might not be involved in overweight and obesity, at least based on genetic backgrounds. However, further studies must measure RAS components to elucidate this question.

Prevalência de doença arterial periférica e fatores de risco associado em uma população rural brasileira: estudo Corações de Baependi / Prevalence of peripheral artery disease and associated risk factors in a brazilian rural population: the Baependi heart study

A identificação da doença arterial periférica (DAP) pode atenuar a progressão e suas complicações adicionais, uma vez que a DAP é um fator de risco para mortalidade geral e cardiovascular. Avaliar a prevalência de DAP na população do Estudo Corações de Baependi e investigar fatores de risco associados em diferentes grupos etários. Foram selecionados 1.627 indivíduos (ambos os sexos e idade entre 18 e 102 anos) residentes no município de Baependi (Minas Gerais, Brasil). Os parâmetros antropométricos e bioquímicos foram avaliados por meio de protocolos padrões. O nível de atividade física foi determinado pelo Questionário Internacional de Atividade Física - Versão Curta (IPAQ-SF). A triagem da DAP foi realizada pelo índice tornozelo-braço (ITB). O nível de significância estatística adotado nas análises foi de 5%. Na população total, a prevalência de DAP foi de 1,05% e atingiu 5,2% após os 70 anos de idade. A frequência e intensidade do tabagismo foram maiores nos indivíduos com DAP. Uma história prévia de infarto do miocárdio e maior prevalência de hipertensão, diabetes, obesidade e sedentarismo também estiveram associados à DAP. Além disso, a DAP foi mais frequente em negros que em brancos. Após análise multivariada, a idade, diabetes, tabagismo e inatividade física permaneceram independentemente associados à DAP. A prevalência de DAP foi baixa e claramente aumentou com a idade em nossa amostra de uma população rural brasileira. Além disso, os principais fatores de risco para DAP foram tabagismo, sedentarismo, diabetes e idade

The identification of peripheral artery disease (PAD) can help prevent further progression of the disease and additional complications, considering that this condition is a risk factor for all-cause mortality and cardiovascular death. To assess the prevalence of PAD in the Baependi Heart Study and investigate associated risk factors in different age groups. A total of 1,627 individuals (of both genders and aged 18 - 102 years) residing in the municipality of Baependi (Minas Gerais, Brazil) were selected for this study. Anthropometric and biochemical parameters were evaluated by standard techniques. Physical activity level was determined by the International Physical Activity Questionnaire - Short Form (IPAQ-SF). The screening of PAD was performed by determination of the ankle-brachial index (ABI). The level of statistical significance was set at 5%. In the overall sample, the prevalence of PAD was 1.05%, and reached 5.2% after the age of 70 years. The frequency and intensity of smoking were higher in individuals with PAD. A prior history of myocardial infarction and a higher prevalence of hypertension, diabetes, obesity, and sedentary lifestyle were also associated with PAD. In addition, PAD was more frequent in blacks than whites. In multivariable analysis, age, diabetes, smoking, and physical inactivity remained independently associated with PAD. The prevalence of PAD was low and increased clearly with age in our sample from a Brazilian rural population. Furthermore, the main risk factors for PAD in the investigated sample were smoking, sedentary lifestyle, diabetes mellitus, and age

Non-HDL cholesterol is a good predictor of the risk of increased arterial stiffness in postmenopausal women in an urban Brazilian population

OBJECTIVES: Increased arterial stiffness is an important determinant of the risk of cardiovascular disease. Lipid profile impairment, especially hypercholesterolemia, is associated with stiffer blood vessels. Thus, the aim of this study was to determine which of the five circulating lipid components (high-density lipoprotein cholesterol (HDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), low-density lipoprotein cholesterol (LDL), total cholesterol (TC) and triglycerides) is the best predictor of increased arterial stiffness in an urban Brazilian population. METHODS: A random sample of 1,662 individuals from the general population of Vitoria, Brazil (25-64 years), was selected, and lipid components were measured using standard methods. Pulse wave velocity was measured using a non-invasive automatic device, and increased arterial stiffness was defined as a pulse wave velocity ≥10 m/s. RESULTS: In men, only total cholesterol (OR=1.59; CI=1.02 to 2.48, p=0.04) was associated with the risk of increased arterial stiffness. In women, HDL-C (OR=1.99; CI=1.18 to 3.35, p=0.01) and non-HDL-C (OR=1.61; CI=1.01 to 2.56, p=0.04) were good predictors of the risk of increased arterial stiffness. However, these associations were only found in postmenopausal women (OR=2.06; CI=1.00 to 4.26, p=0.05 for HDL-C and OR=1.83; CI=1.01 to 3.33, p=0.04 for non-HDL-C). CONCLUSION: Our findings indicate that both HDL-C and non-HDL-C are good predictors of the risk of increased arterial stiffness in postmenopausal women in an urban Brazilian population and may be useful tools for assessing the risk of arterial stiffness.

Lamellar keratoplasty in rabbits using an allogeneic free omental graft and omentum-derived mesenchymal cells associated with the canine amniotic membrane / Ceratoplastia lamelar em coelhos usando enxerto de omento alógeno livre e células mesenquimais omentais associadas com membrana amniótica canina

ABSTRACT: The objective of this research was to evaluate the clinical and microscopic effects in rabbits of lamellar keratoplasty using allogeneic omentum associated with canine amniotic membrane (AM). Rabbits were divided into two groups: one received the allogeneic free omental graft covered with the AM (OM-graft group), while the other received the AM graft containing omental mesenchymal cells (OM-cell group). Clinical signs were evaluated on different postoperative days. After the clinical assessments, the rabbits were euthanized and their corneas were obtained for histopathology and immunohistochemistry (Ki-67, marker for proliferation). Both groups showed chemosis, blepharospasm, eye discharge, hyperemia, and corneal opacity/edema. Neovascularization was observed in the OM-cell group. Histopathological evaluation revealed epithelial islands within the stroma of OM-cell samples. Thirty days after surgery, complete corneal re-epithelialization had occurred in both groups. The OM-cell group showed more Ki-67 positive cells. The free omentum and its cells, combined with the AM, contributed to corneal repair, a process that was completed 30 days after lamellar keratoplasty.

RESUMO: Objetivou-se, com a pesquisa, avaliar os efeitos clínicos e microscópicos da associação do omento de coelho com a membrana amniótica (AM) canina, na ceratoplastia lamelar em coelhos. Dois grupos foram constituídos: um recebeu enxerto de omento alógeno livre, recoberto por AM (grupo OM- graft); o outro recebeu enxerto de AM contendo células mesenquimais derivadas do omento (grupo OM-cell). Manifestações clínicas foram avaliadas em diferentes tempos de pós-operatórios. Após as avaliações clínicas, coelhos foram submetidos à eutanásia e córneas foram colhidas para histopatologia e imunohistoquímica (Ki-67, marcador de proliferação). Relativamente às manifestações clínicas, ambos os grupos apresentaram sinais de quemose, blefarospasmo, secreção ocular, hiperemia e opacidade/edema. Neovascularização foi observada no grupo OM-cell. Avaliações à histopatologia mostraram que uma amostra de OM-cell apresentou ilhas de epitélio dentro do estroma. Aos 30 dias de pós-operatório, observou-se reepitelização corneal completa, em OM-graft e OM-cell. O grupo OM-cell apresentou mais células positivas para Ki-67. O omento livre e suas células, associados à AM, contribuíram para a reparação corneal, que se completou após 30 dias de ceratoplastia lamelar.

Aerobic exercise training induces an anti-apoptotic milieu in myocardial tissue / Treinamento físico aeróbico induz ambiente anti-apoptótico em tecido miocárdico / La práctica de ejercicio aeróbico induce un ambiente anti-apoptótico en tejido miocárdico

This study evaluated modulators of apoptosis in the myocardium of rats subjected to exercise training. Rats were assigned to non-trained and exercise-trained groups, respectively. The animals ran for 1 h per day, 6 times per week and, for a total of 13 weeks. The left ventricle was processed for analysis of gene and protein anti- (Bcl-2, c-IAP1, c-IAP2, Survivin, ILK, Akt and pAkt) and pro- (Bad) apoptotic expression by real-time PCR (except for Akt and pAkt) and Western blot, respectively. The Bad mRNA (p<0.05), but not the protein expression (p = 0.19), was significantly lower after training. The exercise training significantly increased the gene and protein expression for all anti-apoptotic factors. However, a significant change in the c-IAP2 was seen only for gene expression (p<0.05). The present findings indicate that exercise can create a favorable milieu for the survival of cardiomyocytes when apoptosis is increased...

Este estudo analisou moduladores de apoptose no miocárdio de ratos submetidos a treinamento físico. Os ratos foram distribuídos nos seguintes grupos, respectivamente: não treinados; treinados. Os animais realizaram exercício em esteira (60 min./dia; 6 x semana) por 13 semanas. O ventrículo esquerdo foi processado para análise da expressão gênica e protéica de fatores anti-apoptóticos (Bcl-2, c-IAP1, c-IAP2, Survivina, ILK, Akt e pAkt) e pro-apoptóticos (Bad) por PCR em tempo real (exceto Akt e pAkt) e Western blot, respectivamente. O teor de RNAm da Bad (p<0,05) foi significativamente reduzido após treinamento. Porém, a expressão protéica da Bad não foi diferente entre os grupos. A expressão gênica e proteica de todos os fatores anti-apoptóticos foi significativamente aumentada com o treinamento. A exceção foi para c-IAP2, que aumentou somente em nível transcripcional (p<0,05). Os achados deste estudo indicam que o exercício cria um ambiente favorável para sobrevivência dos cardiomiócitos a apoptose...

El estudio analizó moduladores de la apoptosis en el miocardio de ratas entrenadas físicamente. Las ratas se dividieron en no entrenado y entrenadas. Los animales se ha ejecutado (60 por día x 6 semanas) a las 13 semanas. El ventrículo izquierdo se procesan para el análisis de la expresión de sus genes y proteínas que inhiben (Bcl-2, c-IAP1, c-IAP2, survivina, ILK, Akt y pAkt) y causa (Bad) de la apoptosis por PCR en tiempo real (excepto Akt y pAkt) y Western blot. El nivel de ARNm de Bad (p<0,05) se redujo después de la entrenamiento, pero no era diferente de proteína. La expresión de los inhibidores de la apoptosis fue significativamente mayor con la entrenamiento. La excepción fue para c-IAP2, que aumentó sólo en el nivel transcripcional (p<0,05). Los resultados de este estudio indican que el ejercicio crea un entorno buen para la supervivencia de la apoptosis de los cardiomiocitos...

Bandagem ajustável do tronco pulmonar: IX: atividade da G6PD do miocárdio de cabras adultas submetido ao treinamento ventricular / Reversible pulmonary trunk banding: IX. G6PD activity of adult goat myocardium submitted to ventricular retraining

OBJETIVO: O aumento da atividade miocárdica da Glicose 6-Fosfato Desidrogenase tem sido demonstrado na insuficiência cardíaca. Este estudo avalia a atividade miocárdica da Glicose 6-Fosfato Desidrogenase no treinamento do ventrículo subpulmonar de cabras adultas. MÉTODOS: Foram utilizadas 18 cabras adultas, divididas em três grupos: convencional (bandagem fixa), sham e intermitente (bandagem ajustável; 12 horas diárias de sobrecarga). A sobrecarga sistólica (70% da pressão sistêmica) foi mantida durante quatro semanas. As avaliações hemodinâmica e ecocardiográfica foram realizadas durante todo o estudo. Depois de cumprido o protocolo, os animais foram mortos para avaliação morfológica e da atividade da Glicose 6-Fosfato Desidrogenase dos ventrículos. RESULTADOS: Apesar de haver sobrecarga sistólica proporcionalmente menor no ventrículo subpulmonar do grupo intermitente (P=0,001), ambos os grupos de estudo apresentaram aumento da massa muscular de magnitude similar. Os grupos intermitente e convencional apresentaram aumento da massa de 55,7% e 36,7% (P<0,05), respectivamente, em comparação ao grupo sham. O conteúdo de água do miocárdio não variou entre os grupos estudados (P=0,27). O ecocardiograma demonstrou maior aumento (37,2%) na espessura do ventrículo subpulmonar do grupo intermitente, em relação aos grupos sham e convencional (P<0,05). Foi observada maior atividade da Glicose 6-Fosfato Desidrogenase na hipertrofia miocárdica do ventrículo subpulmonar do grupo convencional, comparada aos grupos sham e intermitente (P=0,05). CONCLUSÃO: Ambos os grupos de treinamento ventricular desenvolveram hipertrofia ventricular, a despeito do menor tempo de sobrecarga sistólica no grupo intermitente. A maior atividade de Glicose 6-Fosfato Desidrogenase observada no grupo convencional pode refletir um desequilíbrio redox, com maior produção de fosfato de dinucleotídeo de nicotinamida e adenina e glutationa reduzida, um mecanismo importante da fisiopatologia da insuficiência cardíaca.

OBJECTIVE: Increased glucose 6-phosphate dehydrogenase activity has been demonstrated in heart failure. This study sought to assess myocardial glucose 6-phosphate dehydrogenase activity in retraining of the subpulmonary ventricle of adult goats. METHODS: Eighteen adult goats were divided into three groups: traditional (fixed banding), sham, and intermittent (adjustable banding, daily 12-hour systolic overload). Systolic overload (70% of systemic pressure) was maintained during a 4-week period. Right ventricle, pulmonary artery and aortic pressures were measured throughout the study. All animals were submitted to echocardiographic and hemodynamic evaluations throughout the protocol. After the study period, the animals were killed for morphological and glucose 6-phosphate dehydrogenase activity assessment. RESULTS: A 55.7% and 36.7% increase occurred in the intermittent and traditional right ventricle masses, respectively, when compared with the sham group (P<0.05), despite less exposure of intermittent group to systolic overload. No significant changes were observed in myocardial water content in the 3 groups (P=0.27). A 37.2% increase was found in right ventricle wall thickness of intermittent group, compared to sham and traditional groups (P<0.05). Right ventricle glucose 6-phosphate dehydrogenase activity was elevated in the traditional group, when compared to sham and intermittent groups (P=0.05). CONCLUSION: Both study groups have developed similar right ventricle hypertrophy, regardless less systolic overload exposure of intermittent group. Traditional systolic overload for adult subpulmonary ventricle retraining causes upregulation of myocardial glucose 6-phosphate dehydrogenase activity. It may suggest that the undesirable "pathologic systolic overload" is influenced by activation of penthose pathway and cytosolic Nicotinamide adenine dinucleotide phosphate availability. This altered energy substrate metabolism can elevate levels of free radicals by Nicotinamide adenine dinucleotide phosphate oxidase, an important mechanism in the pathophysiology of heart failure.

O grau de melhora na função das células progenitoras endoteliais derivadas da medula óssea é dependente do volume de treinamento físico aeróbio / The level of improvement in the function of bone marrow derived endothelial progenitor cells is dependent on the volume of aerobic exercise training

INTRODUÇÃO: A angiogênese muscular esquelética induzida pelo treinamento físico aeróbio (TF) é determinante na melhora da capacidade aeróbia. Entre os fatores envolvidos, as células progenitoras endoteliais (CPE) derivadas da medula óssea são descritas por promoverem o reparo vascular e a angiogênese. Embora o papel do TF sobre os parâmetros das CPE tenha sido investigado, pouco se conhece sobre os efeitos de diferentes volumes de TF sobre a função das CPE da medula óssea, alterações metabólicas e capilarização muscular. OBJETIVO: Testar a hipótese de que o TF melhore a função das CPE da medula óssea, acompanhada por maior capilarização e capacidade oxidativa muscular dependentes do aumento de volume de TF. MÉTODOS: Vinte e uma ratas Wistar foram divididas em três grupos: sedentário controle (SC), treinado protocolo 1 (P1), treinado protocolo 2 (P2). P1: o treinamento de natação consistiu de 60 min, 1x/dia, cinco dias/semana/10 semanas, com 5% de sobrecarga corporal. P2: o mesmo de P1 até a oitava semana, na nona semana os animais treinaram 2x/dia e na 10ª semana 3x/dia. RESULTADOS: O TF promoveu bradicardia de repouso, aumento da tolerância ao esforço, do consumo de oxigênio de pico e da atividade da enzima citrato sintase muscular no grupo P1, sendo estas adaptações mais exacerbadas no grupo P2, indicando que a condição aeróbia foi mais proeminente com este TF. O TF melhorou a função das CPE da medula óssea em P1, sendo ainda maior esta resposta no grupo P2. Em paralelo, observa-se também um aumento no número de capilares dependentes do volume de TF. CONCLUSÃO: Estes resultados sugerem que a medula óssea como o principal reservatório de CPE é influenciada por diferentes volumes de TF, sendo possivelmente responsável pelo maior rendimento físico observado mediante uma maior mobilização endógena de CPE, participantes ativas no processo de angiogênese muscular induzido pelo TF.

INTRODUCTION: Skeletal muscle angiogenesis induced by aerobic exercise training (ET) is crucial in the improvement of the aerobic capacity. The endothelial progenitor cells (EPC) derived from bone marrow have been described for promoting both the vascular repair and angiogenesis. Although the role of the ET on the parameters of the EPC has been investigated, the effect of different volumes of ET on the EPC function in bone marrow, skeletal muscle metabolic alterations and capilarization are unknown. OBJECTIVE: We hypothesized that ET improves the EPC function in bone marrow, accompanied by an increase of skeletal muscle oxidative capacity and angiogenesis dependents of the increase of volume of ET. METHODS: Twenty one Wistar rats were divided into 3 groups: sedentary control (SC), trained protocol 1 (T1) and trained protocol 2 (T2). T1: swimming training consisted of 60 min, 1x/day/10weeks, with 5% body weight load. T2 the same as T1 until 8th week, in the 9th week the rats trained 2x/day and in the 10th week 3x/day. RESULTS: ET promoted resting bradycardia, increase of exercise tolerance, peak oxygen uptake and citrate synthase enzyme activity in the T1 group, being these adaptative responses exacerbate in the P2 group, indicating that the aerobic condition was improved in this group. ET improved the EPC function of the bone marrow in T1, and the response was exacerbed in T2 group. In parallel, an increase in the number of capillaries dependent of ET volume was also observed. CONCLUSION: These findings suggest that the bone marrow as the main reservoir of EPC is influenced by different ET volume, possibly being responsible for the improvement of aerobic performance observed by higher endogenous EPC mobilization, active participants in the process of angiogenesis induced by ET.

Non-HFE hemochromatosis

Hereditary hemochromatosis (HH) is an autosomal recessive disorder classically related to HFE mutations. However, since 1996, it is known that HFE mutations explain about 80% of HH cases, with the remaining around 20% denominated non-HFE hemochromatosis. Nowadays, four main genes are implicated in the pathophysiology of clinical syndromes classified as non-HFE hemochromatosis: hemojuvelin (HJV, type 2Ajuvenile HH), hepcidin (HAMP, type 2B juvenile HH), transferrin receptor 2 (TFR2, type 3 HH) and ferroportin (SLC40A1, type 4 HH). The aim of this review is to explore molecular, clinical and management aspects of non-HFE hemochromatosis.

Sildenafil preserves diastolic relaxation after reduction by L-NAME and increases phosphodiesterase-5 in the intercalated discs of cardiac myocytes and arterioles

OBJECTIVES: We investigated the influence of sildenafil on cardiac contractility and diastolic relaxation and examined the distribution of phosphodiesterase-5 in the hearts of hypertensive rats that were treated with by NG-nitro-L-arginine methyl ester (L-NAME). METHODS: Male Wistar rats were treated with L-NAME and/or sildenafil for eight weeks. The Langendorff method was used to examine the effects of sildenafil on cardiac contractility and diastolic relaxation. The presence and location of phosphodiesterase-5 and phosphodiesterase-3 were assessed by immunohistochemistry, and cGMP plasma levels were measured by ELISA. RESULTS: In isolated hearts, sildenafil prevented the reduction of diastolic relaxation (dP/dt) that was induced by L-NAME. In addition, phosphodiesterase-5 immunoreactivity was localized in the intercalated discs between the myocardial cells. The staining intensity was reduced by L-NAME, and sildenafil treatment abolished this reduction. Consistent with these results, the plasma levels of cGMP were decreased in the L-NAME-treated rats but not in rats that were treated with L-NAME + sildenafil. CONCLUSION: The sildenafil-induced attenuation of the deleterious hemodynamic and cardiac morphological effects of L-NAME in cardiac myocytes is mediated (at least in part) by the inhibition of phosphodiesterase-5.

Co-occurring PTPN11 and SOS1 gene mutations in Noonan syndrome: does this predict a more severe phenotype? / Coocorrência de mutações nos genes PTPN11 e SOS1 na síndrome de Noonan: este achado prediz um fenótipo mais grave?

Noonan syndrome (NS) is an autosomal dominant disorder, with variable phenotypic expression, characterized by short stature, facial dysmorphisms and heart disease. Different genes of the RAS/MAPK signaling pathway are responsible for the syndrome, the most common are: PTPN11, SOS1, RAF1, and KRAS. The objective of this study was to report a patient with Noonan syndrome presenting mutations in two genes of RAS/MAPK pathway in order to establish whether these mutations lead to a more severe expression of the phenotype. We used direct sequencing of the PTPN11, SOS1, RAF1, and KRAS genes. We have identified two described mutations in heterozygosity: p.N308D and p.R552G in the genes PTPN11 and SOS1, respectively. The patient has typical clinical features similar to the ones with NS and mutation in only one gene, even those with the same mutation identified in this patient. A more severe or atypical phenotype was not observed, suggesting that these mutations do not exhibit an additive effect.

A síndrome de Noonan (SN) é uma doença gênica autossômica dominante, com expressão clínica variável, caracterizada por baixa estatura, dismorfismos faciais e cardiopatia. Diferentes genes da via de sinalização RAS/MAPK são responsáveis pela síndrome, sendo as mais frequentes: PTPN11, SOS1, RAF1 e KRAS. O objetivo deste estudo foi relatar um paciente com SN que apresenta mutações em dois genes da via RAS/MAPK a fim de estabelecer se essas mutações levam a uma expressão mais grave do fenótipo. Utilizou-se sequenciamento direto dos genes PTPN11, SOS1, RAF1 e KRAS. Foram identificadas duas mutações em heterozigose previamente descritas: p.N308D e p.R552G nos genes PTPN11 e SOS1, respectivamente. A paciente apresenta quadro clínico típico semelhante ao dos pacientes com SN e mutação em um único gene, mesmo naqueles com a mesma mutação identificada na paciente. Não foi observado um fenótipo mais grave ou atípico na paciente, sugerindo que as mutações não apresentam um efeito aditivo.

Marcadores genéticos como biomarcadores: hipertrofia cardíaca como exemplo / Genetic markers as biomarkers: cardiac hypertrophy as an example

A hipertrofia do ventrículo esquerdo constitui um dos mais poderosos de risco independentes para morbidade e mortalidade cardiovascular em pacientes de alto risco e na população geral. No mesmo nível de pressão arterial, alguns indivíduos desenvolvem hipertrofia do ventrículo esquerdo enquanto outros não o fazem, indicando uma suscetibilidade genética a essa condição. A hipertrofia do ventrículo esquerdo pode ser primária em doenças como cardiomiopatia hipertrofica ou, ao menos em parte, como um mecanismo compensatório para ativação crônica neuro-humoral e carga hemodinâmica anormal, sendo considerada uma adaptação estrutural do coração. O aumento da espessura da parede reduz o estresse na parede e mantém o desempenho da parede na presença do aumento da carga mecânica. Estudos recentes sugerem a existência de marcadores de suscetibilidade à hipertrofia em diversos genes, como o da enzima conversora de angiotensina, do angiotensinogênio, dos receptores tipo 1 e 2 da angiotensina II, da aldosterona sintetase, do receptor ativado...

Left ventricular hypertrophy is one of the strongest independent risk factors for cardiovascular morbidity and mortality in high risk patients and the general population. At the same blood pressure level, some individuals develop left ventricular hypertrophy while others do not, indicating a genetic susceptibility to this condition. Left ventricular hypertrophy may be primary in diseases such as hypertrophic cardiomyopathy or it may be partially due to a compensatory mechanism for chronic neurohumoral activation and abnormal hemodynamic load, considered as a structural adaptation of heart. Increased wall thickness reduces wall stress and maintains cardiac performance in the presence of increased mechanical load. Recent studies suggest the existence of markers of susceptibility to hypertrophy in several genes such as angiotensin converting enzyme, angiotensinogen, angiotensin II type 1 and type 2 receptors, aldosterone synthetase, peroxisome proliferator-activated receptor and G-protein ß3 subunit. Since it involves multiple environmental, behavior and genetic factors, the study of left ventricular hypertrophy is a challenge. However, the knowledge of molecular and genetic bases of left ventricular hypertrophy may contribute to a more accurate understanding of the pathogenesis of this condition and offers a promising future for its treatment and prevention.

Knockdown of E2f1 by RNA interference impairs proliferation of rat cells in vitro

E2F1 plays a key role in cell-cycle regulation in mammals, since its transcription factor activity controls genes required for DNA synthesis and apoptosis. E2F1 deregulation is a common feature among different tumor types and can be a major cause of cell proliferation. Thus, blocking E2F1 expression by RNA interference represents a promising therapeutic approach. In this study, the introduction of specific short hairpin RNAs (shRNAs) reduced E2f1 expression by up to 77 percent, and impaired rat glioma cell proliferation by approximately 70 percent, as compared to control cells. Furthermore, we investigated the expression of E2f1 target genes, Cyclin A and Cyclin E. Cyclin A was found to be down-regulated, whereas Cyclin E had similar expression to control cells, indicating that gene(s) other than E2f1 control its transcription. Other E2f family members, E2f2 and E2f3, which have been classified in the same subgroup of transcriptional activators, were also analyzed. Expression of both E2f2 and E2f3 was similar to control cells, showing no cross-inactivation or up-regulation to compensate for the absence of E2f1. Nevertheless, their expression was insufficient to maintain the initial proliferation potential. Taken together, our results suggest that shE2f1 is a promising therapy to control tumor cell proliferation.