Miocardiopatía arritmogénica. Genes y proteínas desmosómicas / Arrhythmogenic Cardiomyopathy. Genes and Desmosomal Proteins

RESUMEN Desde 1996 esta enfermedad figura en la clasificación de las miocardiopatías de la OMS con el nombre de "miocardiopatía arritmogénica". A fines de la década del 70 se estableció que el ventrículo derecho (VD) puede ser el sustrato para el desarrollo de arritmias. En la década del 80 se describió el reemplazo del miocardio por tejido fibroadiposo y su naturaleza hereditaria. Posteriores descubrimientos permitieron la identificación de varios genes implicados en la producción de proteínas desmosómicas que participan en el acoplamiento intercelular lo cual llevó a definir a la miocardiopatía arritmogénica como una enfermedad desmosómica. El electrocardiograma y el ecocardiograma resultaron fundamentales y la angiocardiografía invasiva se utilizó para detectar disquinesia-aquinesia y aneurismas del VD. La biopsia endomiocárdica se perfiló como el gold standard para el diagnóstico, debido a su capacidad para detectar el reemplazo transmural por tejido fibroadiposo. El advenimiento de la resonancia magnética cardíaca (RMC) con realce tardío de gadolinio ha permitido revelar no solamente anomalías morfológico-funcionales sino también daño tisular. El conocimiento de la estructura del disco intercalar, involucrado en el acoplamiento intercelular ha permitido determinar que no solamente los desmosomas estarían comprometidos, sino que habría varias proteínas constituyentes tanto de los desmosomas, como de las uniones adherentes, las uniones gap, y los canales iónicos, integradas en una unidad conocida como "área composita". Ésta constituye una amalgama entre elementos de sostén y canales iónicos que participan en la propagación del potencial de acción, lo que ha permitido desarrollar el concepto de disco intercalar compuesto por los llamados "nodos excitoadhesivos". Las implicancias clínicas en el desarrollo de arritmias malignas son obvias.

ABSTRACT In 1996 this disease was introduced into the WHO classification of cardiomyopathies with the term "arrhythmogenic cardiomyopathy". By the end of the 70s the right ventricle (RV) was identified as a substrate for the development of arrhythmias. The replacement of the myocardium by fibrofatty tissue and the hereditary nature of this condition were described in the 1980s. Later findings led to the identification of several genes involved in the production of desmosomal proteins participating in intercellular coupling, which led to defining arrhythmogenic cardiomyopathy as a desmosomal disease. Electrocardiography and echocardiography are fundamental tools, and invasive angiocardiography was used to detect dyskinesia-akinesia and right ventricular aneurysms. Endomyocardial biopsy was established as the gold standard for the diagnosis due to its ability to detect transmural replacement by fibrofatty tissue. The advent of cardiac magnetic resonance imaging (CMRI) with late gadolinium enhancement reveals morphological and functional abnormalities and tissue damage. The understanding of intercalated disc structure involved in intercellular coupling has made it possible to determine that, apart from desmosomes, several desmosomal proteins, as adherens junctions, gap junctions and ion channels are integrated into a unit known as the " area composita". The area composita constitutes an amalgam between supporting elements and ion channels that participate in action potential propagation, which has led to develop the concept that intercalated discs are constituted by "adhesion/ excitability nodes". The clinical implications in the development of malignant arrhythmias are obvious.

Bretschneider Solution and Two Antianginal Drugs Protect Peripheral Tissue in an Animal Model of Hemorrhagic Shock.

ABSTRACT: Shock and subsequent resuscitation provoke ischemia-reperfusion injury. Trimetazidine (TMZ), allopurinol (ALO), and histidine-tryptophan-ketoglutarate (HTK) solution, can protect from ischemia-reperfusion injury in chronic coronary syndromes and in transplantation. The objective of the current study is to compare, in a hemorrhagic shock and standard resuscitation animal model, organ damage parameters between placebo and treatment with TMZ, ALO, or HTK. Shock was induced in Wistar rats by controlled arterial bleeding, maintaining mean arterial pressure between 38 and 42 mm Hg for 60 minutes; then, drawn blood was reinfused. Animals were divided into: Sham (n = 4), Control (n = 6), TMZ (n = 7), ALO (n = 9), and HTK (n = 7). At the end of the experiment, animals were sacrificed and tissue harvested. TMZ, ALO and HTK decreased histopathologic damage in heart [Control: 1.72 (1.7-1.77); TMZ: 1.75 (1.72-1.79); ALO: 1.75 (1.74-1.8); HTK: 1.82 (1.78-1.85); all P < 0.05], kidney [Control: 3 (2-3); TMZ: 1 (1-2); ALO: 1 (1-1); HTK: 1(1-1); all P < 0.05] and intestine [Control: 3 (2-3); TMZ: 1 (1-2); ALO: 1 (1-1); HTK: 1 (0-2); all P < 0.05]. Also, treatment with TMZ, ALO, and HTK increased immunohistochemical expression of thioredoxin-1 in heart [Control: 6.6 (5.6-7.4); TMZ: 9.5 (8.1-9.7); ALO: 9.1 (8.4-10.2); HTK: 14.2 (12.6-15); all P < 0.05]; and kidney [Control: 4.6 (4-5.1); TMZ: 9.7 (9.3-9.9); ALO: 9.6 (9-9.9); HTK: 16.7 (16.1-17); all P < 0.05]. In an experimental model of hemorrhagic shock, TMZ, ALO, and HTK solution attenuated cell damage in multiple parenchyma and increased antioxidant defenses.

Structural changes in endocrine pancreas of male Wistar rats due to chronic cola drink consumption. Role of PDX-1.

AIM: The objective of this work was to analyze the structural changes of the pancreatic islets in rats, after 6 month consuming regular and light cola for 6 months. Also, we have analyzed the possible role of PDX-1 in that process. Finally, with the available knowledge, we propose a general working hypothesis that explains the succession of phenomena observed. Previously, we reported evidence showing that chronic cola consumption in rats impairs pancreatic metabolism of insulin and glucagon and produces some alterations typically observed in the metabolic syndrome, with an increase in oxidative stress. Of note It is worth mentioning that no apoptosis nor proliferation of islet cells could be demonstrated. In the present study, 36 male Wistar rats were divided into three groups to and given free access to freely drink regular cola (C), light cola (L), or water (W, control). We assessed the impact of the three different beverages in on glucose tolerance, lipid levels, creatinine levels and immunohistochemical changes addressed for the expression of insulin, glucagon, PDX-1 and NGN3 in islet cells, to evaluate the possible participation of PDX-1 in the changes observed in α and ß cells after 6 months of treatment. Moreover, we assessed by stereological methods, the mean volume of islets (Vi) and three important variables: the fractional ß -cell area, the cross-sectional area of alpha (A α-cell) and beta cells (A ß-cell), and the number of ß and α cell per body weight. Data were analyzed by two-way ANOVA followed by Bonferroni's multiple t-test or by Kruskal-Wallis test, then followed by Dunn's test (depending on distribution). Statistical significance was set at p<0.05. Cola drinking caused impaired glucose tolerance as well as fasting hyperglycemia (mean:148; CI:137-153; p<0.05 vs W) and an increase of in insulin immunolabeling (27.3±19.7; p<0.05 vs W and L). Immunohistochemical expression for PDX-1 was significantly high in C group compared to W (0.79±0.71; p<0.05). In this case, we observed cytoplasmatic and nuclear localization. Likewise, a mild but significant decrease of in Vi was detected after 6 months in C compared to W group (8.2±2.5; p<0.05). Also, we observed a significant decrease of in the fractional ß cell area (78.2±30.9; p<0.05) compared to W. Accordingly, a reduced mean value of islet α and ß cell number per body weight (0.05±0.02 and 0.08±0.04 respectively; both p<0.05) compared to W was detected. Interestingly, consumption of light cola increased the Vi (10.7±3.6; p<0.05) compared to W. In line with this, a decreased cross-sectional area of ß-cells was observed after chronic consumption of both, regular (78.2±30.9; p<0.05) and light cola (110.5±24.3; p<0.05), compared to W. As for, NGN3, it was negative in all three groups. Our results support the idea that PDX-1 plays a key role in the dynamics of the pancreatic islets after chronic consumption of sweetened beverages. In this experimental model, the loss of islets cells might be attributed to autophagy, favored by the local metabolic conditions and oxidative stress.

Coronary Intimal Thickening Begins in Fetuses and Progresses in Pediatric Population and Adolescents to Atherosclerosis.

The prevalence of coronary intimal thickening (IT) was assessed in fetuses and pediatric population. We studied the coronary arteries of 63 hearts obtained from fetuses, infants, children, and adolescents, deceased from noncardiac disease or trauma. Histomorphometric analysis, planimetry, and immunohistochemical studies were conducted. Intimal thickening consisted of proliferation of smooth muscle cells and scarce monocytes embedded in amorphous deposits within the internal elastic membrane (IEM). Intermingled lesions of intimal hyperplasia and parietal nonstenotic plaques were also observed. Intimal thickening was found in 10% of 20 fetuses, in 33.3% of 18 infants, 73.3% of 15 children, and 100% of 10 adolescents. A significant correlation (r = 0.671, P < 0.001) was found between the extent of IT and age. The IEM was duplicated or interrupted in 43% of patients, showing a positive correlation with the degree of IT (P = 0.01). Intimal thickening was predominantly found near bifurcation sites in the left anterior descending coronary artery (55.6%) and in zones free of bifurcation in the right coronary artery (75%). In conclusion, the prevalence and extension of IT lesions are higher at older ages within a young population. Intimal thickening may be regarded as the first event occurring in coronary preatherosclerosis, preceding lipid deposition.

Productos intermedios de la cocaína: la pasta base o "paco" / Intermediate products of cocaine: the base paste or "paco"

El uso indebido de drogas se ha convertido en un grave problema a nivel mundial. En los últimos años, en nuestro país se ha incrementado en más del 200% el consumo de pasta base de cocaína (paco). A pesar de que el paco es un producto intermedio en la obtención de cocaína, y que muchos de sus efectos son atribuibles al contenido de esa droga, su consumo produce un cuadro clínico claramente distinto al observado en los consumidores de clorhidrato de cocaína, lo cual puede estar relacionado con su impureza. Sin perjuicio del gran impacto social producido por el consumo de paco, poco se sabe sobre su composición química y menos aún sobre sus efectos crónicos en los distintos órganos ni sobre su fisiopatología. Si bien existe material de autopsia de adictos al paco, los hallazgos están contaminados por la coexistencia en un mismo paciente de múltiples tóxicos. Urge la formación de grupos multidisciplinarios, con moderna tecnología para enfrentar este gravísimo flagelo. (AU)

Drug abuse has become a serious problem worldwide. In recent years, in our country the consumption of cocaine base paste (Paco) has increased by more than 200%. Despite of the fact that Paco is an intermediate product in the manufacture of cocaine, and that many of its effects are attributable to its content, its consumption produces a clearly different clinical picture than that observed in cocaine hydrochloride users, which It may be related to the impurity of this drug. Without prejudice to the great social impact produced by the consumption of this drug, little is known about its chemical composition and even less about its chronic effects on the different organs or its pathophysiology. Although there is an autopsy material for drug addicts, the findings are contaminated by the coexistence of multiple toxins in the same patient. The formation of multidisciplinary groups is urgent, with modern technology to face this very serious scourge. (AU)

Metabolic Syndrome and Neuroprotection.

Introduction: Over the years the prevalence of metabolic syndrome (MetS) has drastically increased in developing countries as a major byproduct of industrialization. Many factors, such as the consumption of high-calorie diets and a sedentary lifestyle, bolster the spread of this disorder. Undoubtedly, the massive and still increasing incidence of MetS places this epidemic as an important public health issue. Hereon we revisit another outlook of MetS beyond its classical association with cardiovascular disease (CVD) and Diabetes Mellitus Type 2 (DM2), for MetS also poses a risk factor for the nervous tissue and threatens neuronal function. First, we revise a few essential concepts of MetS pathophysiology. Second, we explore some neuroprotective approaches in MetS pertaining brain hypoxia. The articles chosen for this review range from the years 1989 until 2017; the selection criteria was based on those providing data and exploratory information on MetS as well as those that studied innovative therapeutic approaches. Pathophysiology: The characteristically impaired metabolic pathways of MetS lead to hyperglycemia, insulin resistance (IR), inflammation, and hypoxia, all closely associated with an overall pro-oxidative status. Oxidative stress is well-known to cause the wreckage of cellular structures and tissue architecture. Alteration of the redox homeostasis and oxidative stress alter the macromolecular array of DNA, lipids, and proteins, in turn disrupting the biochemical pathways necessary for normal cell function. Neuroprotection: Different neuroprotective strategies are discussed involving lifestyle changes, medication aimed to mitigate MetS cardinal symptoms, and treatments targeted toward reducing oxidative stress. It is well-known that the routine practice of physical exercise, aerobic activity in particular, and a complete and well-balanced nutrition are key factors to prevent MetS. Nevertheless, pharmacological control of MetS as a whole and pertaining hypertension, dyslipidemia, and endothelial injury contribute to neuronal health improvement. Conclusion: The development of MetS has risen as a risk factor for neurological disorders. The therapeutic strategies include multidisciplinary approaches directed to address different pathological pathways all in concert.

Cardioprotection after acute exposure to simulated high altitude in rats. Role of nitric oxide.

AIM: In previous studies, upregulation of NOS during acclimatization of rats to sustained hypobaric hypoxia was associated to cardioprotection, evaluated as an increased tolerance of myocardium to hypoxia/reoxygenation. The objective of the present work was to investigate the effect of acute hypobaric hypoxia and the role of endogenous NO concerning cardiac tolerance to hypoxia/reoxygenation under ß-adrenergic stimulation. METHODS: Rats were submitted to 58.7 kPa in a hypopressure chamber for 48 h whereas their normoxic controls remained at 101.3 kPa. By adding NOS substrate L-arg, or blocker L-NNA, isometric mechanical activity of papillary muscles isolated from left ventricle was evaluated at maximal or minimal production of NO, respectively, under ß-adrenergic stimulation by isoproterenol, followed by 60/30 min of hypoxia/reoxygenation. Activities of NOS and cytochrome oxidase were evaluated by spectrophotometric methods and expression of HIF1-α and NOS isoforms by western blot. Eosin and hematoxiline staining were used for histological studies. RESULTS: Cytosolic expression of HIF1-α, nNOS and eNOS, and NO production were higher in left ventricle of hypoxic rats. Mitochondrial cytochrome oxidase activity was decreased by hypobaric hypoxia and this effect was reversed by L-NNA. After H/R, recovery of developed tension in papillary muscles from normoxic rats was 51-60% (regardless NO modulation) while in hypobaric hypoxia was 70% ±â€¯3 (L-arg) and 54% ±â€¯1 (L-NNA). Other mechanical parameters showed similar results. Preserved histological architecture was observed only in L-arg papillary muscles of hypoxic rats. CONCLUSION: Exposure of rats to hypobaric hypoxia for only 2 days increased NO synthesis leading to cardioprotection.

Cardiorenal Involvement in Metabolic Syndrome Induced by Cola Drinking in Rats: Proinflammatory Cytokines and Impaired Antioxidative Protection.

We report experimental evidence confirming renal histopathology, proinflammatory mediators, and oxidative metabolism induced by cola drinking. Male Wistar rats drank ad libitum regular cola (C, n = 12) or tap water (W, n = 12). Measures. Body weight, nutritional data, plasma glucose, cholesterol fractions, TG, urea, creatinine, coenzyme Q10, SBP, and echocardiograms (0 mo and 6 mo). At 6 months euthanasia was performed. Kidneys were processed for histopathology and immunohistochemistry (semiquantitative). Compared with W, C rats showed (I) overweight (+8%, p < 0.05), hyperglycemia (+11%, p < 0.05), hypertriglyceridemia (2-fold, p < 0.001), higher AIP (2-fold, p < 0.01), and lower Q10 level (-55%, p < 0.05); (II) increased LV diastolic diameter (+9%, p < 0.05) and volume (systolic +24%, p < 0.05), posterior wall thinning (-8%, p < 0.05), and larger cardiac output (+24%, p < 0.05); (III) glomerulosclerosis (+21%, p < 0.05), histopathology (+13%, p < 0.05), higher tubular expression of IL-6 (7-fold, p < 0.001), and TNFα (4-fold, p < 0.001). (IV) Correlations were found for LV dimensions with IL-6 (74%, p < 0.001) and TNFα (52%, p < 0.001) and fully abolished after TG and Q10 control. Chronic cola drinking induced cardiac remodeling associated with increase in proinflammatory cytokines and renal damage. Hypertriglyceridemia and oxidative stress were key factors. Hypertriglyceridemic lipotoxicity in the context of defective antioxidant/anti-inflammatory protection due to low Q10 level might play a key role in cardiorenal disorder induced by chronic cola drinking in rats.

Exercise Ameliorates Endocrine Pancreas Damage Induced by Chronic Cola Drinking in Rats.

PURPOSE: This study evaluates whether the daily practice of an exercise routine might protect from endocrine pancreas damage in cola drinking rats. METHODS: Forty-eight Wistar rats were randomly assigned to 4 groups depending on a) beverage consumption ad libitum, water (W) or cola beverage (C), and b) physical activity, sedentary (S) or treadmill running (R). Accordingly, 4 groups were studied: WS (water sedentary), WR (water runner), CS (cola sedentary) and CR (cola runner). Body weight, nutritional data, plasma levels of glucose, creatinine, total cholesterol and cholesterol fractions, and triglycerides (enzymocolorimetry), and systolic blood pressure (plethysmography) were measured. After 6 months, euthanasia was performed (overdose sodium thiopental). Pancreatic tissue was immediately excised and conventionally processed for morphometrical and immunohistochemical determinations. RESULTS: The effects of running and chronic cola drinking on pancreas morphology showed interaction (p<0.001) rather than simple summation. Cola drinking (CS vs WS) reduced median pancreatic islet area (-30%, 1.8 10(4) µm2 vs 2.58 10(4) µm2, p<0.0001) and median ß-cell mass (-43%, 3.81 mg vs 6.73 mg, p<0.0001), and increased median α/ß ratio (+49%, 0.64 vs 0.43, p< 0.001). In water drinking rats (WR vs WS), running reduced median α-cell mass (-48%, 1.48 mg vs 2.82 mg, p<0.001) and α/ß ratio (-56%, 0.19 vs 0.43, p<0.0001). Differently, in cola drinking rats (CR vs CS), running partially restored median islet area (+15%, 2.06 10(4) µm2 vs 1.79 10(4) µm2, p<0.05), increased median ß-cell mass (+47%, 5.59 mg vs 3.81 mg, p <0.0001) and reduced median α/ß ratio (-6%, 0.60 vs 0.64, p<0.05). CONCLUSION: This study is likely the first reporting experimental evidence of the beneficial effect of exercise on pancreatic morphology in cola-drinking rats. Presently, the increase of nearly 50% in ß cells mass by running in cola drinking rats is by far the most relevant finding. Moderate running, advisably indicated in cola consumers and patients at risk of diabetes, finds here experimental support.

Beneficial Effect of Moderate Exercise in Kidney of Rat after Chronic Consumption of Cola Drinks.

AIM: The purpose of this study was to investigate the effect of moderate intensity exercise on kidney in an animal model of high consumption of cola soft drinks. METHODS: Forty-eight Wistar Kyoto rats (age: 16 weeks; weight: 350-400 g) were assigned to the following groups: WR (water runners) drank water and submitted to aerobic exercise; CR (cola runners) drank cola and submitted to aerobic exercise; WS (water sedentary) and CS (cola sedentary), not exercised groups. The aerobic exercise was performed for 5 days per week throughout the study (24 weeks) and the exercise intensity was gradually increased during the first 8 weeks until it reached 20 meters / minute for 30 minutes. Body weight, lipid profile, glycemia, plasma creatinine levels, atherogenic index of plasma (AIP) and systolic blood pressure (SBP) were determined. After 6 months all rats were sacrificed. A kidney histopathological score was obtained using a semiquantitative scale. Glomerular size and glomerulosclerosis were estimated by point-counting. The oxidative stress and pro-inflammatory status were explored by immunohistochemistry. A one way analysis of variance (ANOVA) with Tukey-Kramer post-hoc test or the Kruskal-Wallis test with Dunn's post-hoc test was used for statistics. A value of p < 0.05 was considered significant. RESULTS: At 6 months, an increased consumption of cola soft drink was shown in CS and CR compared with water consumers (p<0.0001). Chronic cola consumption was associated with increased plasma triglycerides, AIP, heart rate, histopathological score, glomerulosclerosis, oxidative stress and pro-inflammatory status. On the other hand, moderate exercise prevented these findings. No difference was observed in the body weight, SBP, glycemia, cholesterol and plasma creatinine levels across experimental groups. CONCLUSIONS: This study warns about the consequences of chronic consumption of cola drinks on lipid metabolism, especially regarding renal health. Additionally, these findings emphasize the protective role of exercise training on renal damage.