Decreased myocardial Titin expression in chronic alcoholic cardiomyopathy

Aims: Cardiomyopathy (CMP) with a reduced ejection fraction develops in a dose-28 dependent manner in one- third of subjects with a long-term history of heavy daily alcohol consumption. Ethanol alters heart transduction signals including excitation- contraction sarcomeric coupling, causing diastolic and systolic left-ventricular (LV) dysfunction. Titin is a giant structural sarcomeric filament macro protein involved in contractile heart function and contributes to cardiac myocyte elastic recoil, a key factor for diastolic LV filling. We evaluated whether titin expression is affected by chronic high-dose ethanol 35 consumption in alcoholic CMP. Methods and Results: We analyzed a total of 30 heart samples from human organ 37 donors: 20 from high alcohol consumers (10 without CMP and 10 with CMP) and 10 healthy controls. Patient evaluation comprised daily and lifetime ethanol consumption, chest X ray, 2-D echocardiography and LV histology. CMP was assessed by functional 40 and histological criteria. Titin activity was evaluated by specific immunohistochemical 41 (IHC) and transcript expression (rtPCR) assays. Titin IHC expression was clearly present in sarcomere areas of myocytes. Compared to healthy donors (82.58±3.36), alcohol consumers showed a significantly lower cardiac titin expression (71.29±3.16; 13.67±3.83% decrease; p=0.04), being significantly lower in alcohol consumers with CMP (62.31±4.18; 24.54±5.06% decrease, p<0.0009), compared to both their counter-parts without CMP (80.27±2.62; 2.80±3.17% decrease 47 vs. controls; p<0.0030 vs. alcoholic CMP). Titin transcript levels confirmed similar patterns of expression

Autophagy is Involved in Cardiac Remodeling in Response to Environmental Temperature Change

Objectives: To study the reversibility of cold-induced cardiac hypertrophy and the role of autophagy in this process. Background: Chronic exposure to cold is known to cause cardiac hypertrophy independent of blood pressure elevation. The reversibility of this process and the molecular mechanisms involved are unknown. Methods: Studies were performed in two-month-old mice exposed to cold (4°C) for 24 h or 10 days. After exposure, the animals were returned to room temperature (21°C) for 24 h or 1 week. Results: We found that chronic cold exposure significantly increased the heart weight/tibia length (HW/TL) ratio, the mean area of cardiomyocytes, and the expression of hypertrophy markers, but significantly decreased the expression of genes involved in fatty acid oxidation. Echocardiographic measurements confirmed hypertrophy development after chronic cold exposure. One week of deacclimation for cold-exposed mice fully reverted the morphological, functional, and gene expression indicators of cardiac hypertrophy. Experiments involving injection of leupeptin at 1 h before sacrifice (to block autophagic flux) indicated that cardiac autophagy was repressed under cold exposure and re-activated during the first 24 h after mice were returned to room temperature. Pharmacological blockage of autophagy for 1 week using chloroquine in mice subjected to deacclimation from cold significantly inhibited the reversion of cardiac hypertrophy. Conclusion: Our data indicate that mice exposed to cold develop a marked cardiac hypertrophy that is reversed after 1 week of deacclimation. We propose that autophagy is a major mechanism underlying the heart remodeling seen in response to cold exposure and its posterior reversion after deacclimation

Response of the human myocardium to ischemic injury and preconditioning: The role of cardiac and comorbid conditions, medical treatment, and basal redox status

Vàlvula aòrtica; Isquèmia; MiocardiVálvula aórtica; Isquemia; MiocardioAortic valve; Ischemia; MyocardiumBackground The diseased human myocardium is highly susceptible to ischemia/reoxygenation (I/R)-induced injury but its response to protective interventions such as ischemic preconditioning (IPreC) is unclear. Cardiac and other pre-existing clinical conditions as well as previous or ongoing medical treatment may influence the myocardial response to I/R injury and protection. This study investigated the effect of both on myocardial susceptibility to I/R-induced injury and the protective effects of IPreC. Methods and results Atrial myocardium from cardiac surgery patients (n = 300) was assigned to one of three groups: aerobic control, I/R alone, and IPreC. Lactate dehydrogenase leakage, as a marker of cell injury, and cell viability were measured. The basal redox status was determined in samples from 90 patients. The response to I/R varied widely. Myocardium from patients with aortic valve disease was the most susceptible to injury whereas myocardium from dyslipidemia patients was the least susceptible. Tissue from females was better protected than tissue from males. Myocardium from patients with mitral valve disease was the least responsive to IPreC. The basal redox status was altered in the myocardium from patients with mitral and aortic valve disease. Conclusions The response of the myocardium to I/R and IPreC is highly variable and influenced by the underlying cardiac pathology, dyslipidemia, sex, and the basal redox status. These results should be taken into account in the design of future clinical studies on the prevention of I/R injury and protection.This study was supported by the Instituto de Salud Carlos III (FIS) [grant number 12/00119]

Preclinical scenario of targeting myocardial fibrosis with chimeric antigen receptor (CAR) immunotherapy

Fibrosis is present in an important proportion of myocardial disorders. Injury activates cardiac fibroblasts, which deposit excess extracellular matrix, increasing tissue stiffness, impairing cardiac function, and leading to heart failure. Clinical therapies that directly target excessive fibrosis are limited, and more effective treatments are needed. Immunotherapy based on chimeric antigen receptor (CAR) T cells is a novel technique that redirects T lymphocytes toward specific antigens to eliminate the target cells. It is currently used in haematological cancers but has demonstrated efficacy in mouse models of hypertensive cardiac fibrosis, with activated fibroblasts as the target cells. CAR T cell therapy is associated with significant toxicities, but CAR natural killer cells can overcome efficacy and safety limitations. The use of CAR immunotherapy offers a potential alternative to current therapies for fibrosis reduction and restoration of cardiac function in patients with myocardial fibrosis

Meteorin-like/ Meteorin-b protects heart against cardiac dysfunction

Meteorin-like/Meteorin-β (Metrnl/Metrnβ) is a secreted protein produced by skeletal muscle and adipose tissue that exerts metabolic actions that improve glucose metabolism. The role of Metrnβ in cardiac disease is completely unknown. Here, we show that Metrnβ-null mice exhibit asymmetrical cardiac hypertrophy, fibrosis, and enhanced signs of cardiac dysfunction in response to isoproterenol-induced cardiac hypertrophy and aging. Conversely, adeno-associated virus-mediated specific overexpression of Metrnβ in the heart prevents the development of cardiac remodeling. Furthermore, Metrnβ inhibits cardiac hypertrophy development in cardiomyocytes in vitro, indicating a direct effect on cardiac cells. Antibody-mediated blockage of Metrnβ in cardiomyocyte cell cultures indicated an autocrine action of Metrnβ on the heart, in addition to an endocrine action. Moreover, Metrnβ is highly produced in the heart, and analysis of circulating Metrnβ concentrations in a large cohort of patients reveals that it is a new biomarker of heart failure with an independent prognostic value

Deep Learning Analyses to Delineate the Molecular Remodeling Process after Myocardial Infarction

Specific proteins and processes have been identified in post-myocardial infarction (MI) pathological remodeling, but a comprehensive understanding of the complete molecular evolution is lacking. We generated microarray data from swine heart biopsies at baseline and 6, 30, and 45 days after infarction to feed machine-learning algorithms. We cross-validated the results using available clinical and experimental information. MI progression was accompanied by the regulation of adipogenesis, fatty acid metabolism, and epithelial-mesenchymal transition. The infarct core region was enriched in processes related to muscle contraction and membrane depolarization. Angiogenesis was among the first morphogenic responses detected as being sustained over time, but other processes suggesting post-ischemic recapitulation of embryogenic processes were also observed. Finally, protein-triggering analysis established the key genes mediating each process at each time point, as well as the complete adverse remodeling response. We modeled the behaviors of these genes, generating a description of the integrative mechanism of action for MI progression. This mechanistic analysis overlapped at different time points; the common pathways between the source proteins and cardiac remodeling involved IGF1R, RAF1, KPCA, JUN, and PTN11 as modulators. Thus, our data delineate a structured and comprehensive picture of the molecular remodeling process, identify new potential biomarkers or therapeutic targets, and establish therapeutic windows during disease progression

Prospective individual patient data meta-analysis of two randomized trials on convalescent plasma for COVID-19 outpatients

Data on convalescent plasma (CP) treatment in COVID-19 outpatients are scarce. We aimed to assess whether CP administered during the first week of symptoms reduced the disease progression or risk of hospitalization of outpatients. Two multicenter, double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when = 50 years and symptomatic for <= 7days were included. The intervention consisted of 200-300mL of CP with a predefined minimum level of antibodies. Primary endpoints were a 5-point disease severity scale and a composite of hospitalization or death by 28 days. Amongst the 797 patients included, 390 received CP and 392 placebo; they had a median age of 58 years, 1 comorbidity, 5 days symptoms and 93% had negative IgG antibody-test. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The odds ratio (OR) of CP for improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311); OR for hospitalization or death was 0.919 (CI 0.592-1.416). CP effect on hospital admission or death was largest in patients with <= 5 days of symptoms (OR 0.658, 95%CI 0.394-1.085). CP did not decrease the time to full symptom resolution

Nous factors implicats en la patologia cardíaca i l’obesitat

[eng] Cardiovascular diseases are one of the leading causes of mortality in industrialized countries and are caused by genetic factors, environmental factors or comorbidities. This thesis is focused on three cardiovascular risk factors such as hypertension, alcoholism and obesity. These pathologies are mainly characterized by hypertrophy and cardiac fibrosis. In recent last years, cardiomyokines have been described as cardioprotective factors against pathological stimuli. One of the most important cardiomyokines is Fibroblast growth factor 21 (FGF21). FGF21 is released by the heart under cardiac stress situations where acts in a autocrine or paracrine manner protecting cardiomyocytes against inflammation, oxidative stress and apoptosis. FGF21 has been described as a protective factor against cardiac hypertrophy, atherosclerosis, ischemia and other cardiac pathologies. In the first part this thesis has studied the role of FGF21 in hypertensive and alcoholic cardiomyopathy. It has been identified that FGF21 gene expression in heart and its circulating levels are induced in response to hypertension, and that FGF21 acts at cardiac level protecting against cardiac fibrosis. Its protective effect has been confirmed in newborn animals treated with FGF21 where cardiac fibrosis was reversed. Moreover, this protective effect on cardiac fibrosis is due to a direct effect of FGF21 on cardiac fibroblasts. It has also been identified that FGF21 gene expression in heart and its circulating levels are induced in response to chronic alcohol consumption. In contrast, lack of FGF21 altered cardiac metabolism, oxidative stress and mitochondrial damage in animals subjected to chronic alcohol consumption. In addition, a positive correlation between myocardial FGF21 levels and oxidative stress have been found in alcoholic patients suggesting a role of FGF21 in the activation of antioxidant defenses during alcoholic cardiomyopathy. On the other hand, this thesis has avaluated two proteins involved in the regulation of energy expenditure through brown adipose tissue (BAT). BAT is the main energy-consuming tissue in mammals. It is considered that BAT may play a role in protecting against obesity. Metrnl is a metabolic regulator that promotes TAM activation while Oncostatin M (OSM) inhibits it. In the last part of this thesis we have studied the role of Metrnl and OSM in obese patients undergoing bariatric surgery. Metrnl circulating levels increase progressively after bariatric surgery while OSM levels decrease in obesity patients undergoing bariatric surgery. This suggests that bariatric surgery modulates circulating levels of these two proteins in an opposite manner in order to activate BAT and promote energy expenditure in these obese patients. In summary, FGF21 appears to play an important role in the protection of cardíac fibrosis induced by hypertensive cardiomyopathy. In addition, FGF21 also appears to play an important role in activating antioxidant defenses during alcoholic cardiomyopathy. Lastly, Metrnl and OSM could be regulated during bariatric surgery to promote energy expenditure activation and protect against obesity

Ischemic postconditioning of the isolated human myocardium: Role of the applied protocol

Ischemic postconditioning (IPostC), has been proposed as a useful approach to reduce infarct size in all species, but its clinical utility remains unclear. To investigate the role played by the protocol used on the efficacy of IPostC in protecting the diseased human myocardium. Myocardial atrial samples from patients were subjected to a 90 min ischemia/120 min reoxygenation followed by different IPostC protocols to investigate the role of the time of ischemia (30, 60, 90 and 120 s) and the number of cycles (1, 2, 3 and 4) with 60 and 120 s of total ischemic time. Muscles were also subjected to ischemic preconditioning (IPreC). The release of lactate dehydrogenase (LDH) and the measurement of tetrazolium bromide (MTT) were determined. IPostC increased the LDH and decreased the MTT values from those of control, independently of the duration of the conditioning ischemia. LDH and MTT values also worsened by augmenting the number of IPostC cycles whereas they were significantly improved by IPreC. However, analysis of individual results indicated that in approximately 1/3 of the cases IPostC exhibited some degree of protection especially in the presence of increased ischemic injury. The present findings show that IPostC of the human myocardium may be influenced by the protocol used and also by the degree of the preceding ischemic injury. IPostC was beneficial in approximately 1/3 of the cases, however in the remaining cases it increased ischemic damage and, therefore, these results raise a word of caution on its broad clinical use