Effects of T3 Administration on Ex Vivo Rat Hearts Subjected to Normothermic Perfusion: Therapeutic Implications in Donor Heart Preservation and Repair.

The present study investigated the effects of triiodothyronine (T3) administration in ex vivo model of rat heart normothermic perfusion. T3 is cardioprotective and has the potential to repair the injured myocardium. Isolated hearts were subjected to normothermic perfusion (NP) with Krebs-Henseleit for 4 h with vehicle (NP) or 60 nM T3 in the perfusate (NP + T3). Left ventricular end diastolic pressure (LVEDP), left ventricular developed pressure (LVDP), perfusion pressure (PP) and percentage of change of these parameters from the baseline values were measured. Activation of stress induced kinase signaling was assessed in tissue samples. Baseline parameters were similar between groups. LVEDP was increased from the baseline by 13% (70) for NP + T3 vs. 139% (160) for NP group, p = 0.048. LVDP was reduced by 18.2% (5) for NP + T3 vs. 25.3% (19) for NP group, p = 0.01. PP was increased by 41% (19) for NP + T3 vs.91% (56) for NP group, p = 0.024. T3 increased activation of pro-survival Akt by 1.85 fold (p = 0.047) and AMPK by 2.25 fold (p = 0.01) and reduced activation of pro-apoptotic p38 MAPK by 3fold (p = 0.04) and p54 JNK by 4.0 fold (p = 0.04). Administration of T3 in normothermic perfusion had favorable effects on cardiac function and perfusion pressure and switched death to pro-survival kinase signaling.

Donor Heart Preservation: Current Knowledge and the New Era of Machine Perfusion.

Heart transplantation remains the conventional treatment in end-stage heart failure, with static cold storage (SCS) being the standard technique used for donor preservation. Nevertheless, prolonged cold ischemic storage is associated with the increased risk of early graft dysfunction attributed to residual ischemia, reperfusion, and rewarming damage. In addition, the demand for the use of marginal grafts requires the development of new methods for organ preservation and repair. In this review, we focus on current knowledge and novel methods of donor preservation in heart transplantation. Hypothermic or normothermic machine perfusion may be a promising novel method of donor preservation based on the administration of cardioprotective agents. Machine perfusion seems to be comparable to cold cardioplegia regarding donor preservation and allows potential repair treatments to be employed and the assessment of graft function before implantation. It is also a promising platform for using marginal organs and increasing donor pool. New pharmacological cardiac repair treatments, as well as cardioprotective interventions have emerged and could allow for the optimization of this modality, making it more practical and cost-effective for the real world of transplantation. Recently, the use of triiodothyronine during normothermic perfusion has shown a favorable profile on cardiac function and microvascular dysfunction, likely by suppressing pro-apoptotic signaling and increasing the expression of cardioprotective molecules.

Low concentrations of bisphenol A promote the activation of the mitochondrial apoptotic pathway on Beta-TC-6 cells via the generation of intracellular reactive oxygen species and mitochondrial superoxide.

Τhe natural history of type 2 diabetes mellitus is characterized by a progressive loss of pancreatic beta cell function and insulin resistance. Bisphenol A (BPA) is an endocrine-disrupting chemical that is used widely in industry; people are exposed to BPA and its products daily. Studies have delineated that BPA alters the function of pancreatic beta cells. Herein, we examined the effect of low doses of BPA on pancreatic beta cell viability and apoptosis and we tried to elucidate the mechanisms involved in these processes. Beta-TC-6 (ATCC® CRL-11506™) cells were cultured with a medium containing the following dilutions of BPA: 0.002, 0.02, 0.1, 0.2, 2 µΜ up to 72 h. We examined the viability and adenosine triphosphate (ATP) levels of cells. Then, we measured apoptosis, cell cycle, and insulin levels. We quantified the levels of proteins implicated in the mitochondrial pathway of apoptosis; and finally, we quantified the intracellular reactive oxygen species and mitochondrial superoxide. We found that the exposure of Beta-TC-6 cells to BPA results in a decrease in cell viability, ATP levels, and an increase in insulin levels. We found an increase in apoptosis levels and a decrease in cell cycle levels. In addition, we provide evidence of the levels of apoptotic proteins. Finally, we found an increase in the cellular reactive oxygen species and mitochondrial superoxide production. Exposure to low concentrations of BPA triggers the mitochondrial pathway of apoptosis via the generation of intracellular reactive oxygen species and mitochondrial superoxide on Beta-TC-6 cells in a dose-dependent way.

Theophrastus Bombastus Von Hohenheim: Theological Reformer, Philosopher and Physician.

Theophrastus Bombastus Von Hohenheim (1493-1541), known as Paracelsus, was a German-Swiss Renaissance man. His interests included alchemy and medicine. During the early 1500s, he worked as a physician, introducing mineral-based therapies to treat ailments. He is credited with developing the first recipe for laudanum, a powerful opium-based pain medication. He had radical beliefs, claiming that supreme knowledge could be reached by observing nature, not by reading books. He expressed rebellious opinions on religious topics and, though devoted Christian, criticized the Catholic Church, preaching that the spirit of Christianity dwells in the human soul and not within the church walls. Paracelsus' efforts to "renovate" the expression of the Christian faith by limiting the ritual and augmenting the spirituality among believers are presented.

Comorbid TNF-mediated heart valve disease and chronic polyarthritis share common mesenchymal cell-mediated aetiopathogenesis.

OBJECTIVES: Patients with rheumatoid arthritis and spondyloarthritisshow higher mortality rates, mainly caused by cardiac comorbidities. The TghuTNF (Tg197) arthritis model develops tumour necrosis factor (TNF)-driven and mesenchymalsynovial fibroblast (SF)-dependent polyarthritis. Here, we investigate whether this model develops, similarly to human patients, comorbid heart pathology and explore cellular and molecular mechanisms linking arthritis to cardiac comorbidities. METHODS: Histopathological analysis and echocardiographic evaluation of cardiac function were performed in the Tg197 model. Valve interstitial cells (VICs) were targeted by mice carrying the ColVI-Cretransgene. Tg197 ColVI-Cre Tnfr1fl/fl and Tg197 ColVI-Cre Tnfr1cneo/cneo mutant mice were used to explore the role of mesenchymal TNF signalling in the development of heart valve disease. Pathogenic VICs and SFs were further analysed by comparative RNA-sequencing analysis. RESULTS: Tg197 mice develop left-sided heart valve disease, characterised by valvular fibrosis with minimal signs of inflammation. Thickened valve areas consist almost entirely of hyperproliferative ColVI-expressing mesenchymal VICs. Development of pathology results in valve stenosis and left ventricular dysfunction, accompanied by arrhythmic episodes and, occasionally, valvular regurgitation. TNF dependency of the pathology was indicated by disease modulation following pharmacological inhibition or mesenchymal-specific genetic ablation or activation of TNF/TNFR1 signalling. Tg197-derived VICs exhibited an activated phenotype ex vivo, reminiscent of the activated pathogenic phenotype of Tg197-derived SFs. Significant functional similarities between SFs and VICs were revealed by RNA-seq analysis, demonstrating common cellular mechanisms underlying TNF-mediated arthritides and cardiac comorbidities. CONCLUSIONS: Comorbidheart valve disease and chronic polyarthritis are efficiently modelled in the Tg197 arthritis model and share common TNF/TNFR1-mediated, mesenchymal cell-specific aetiopathogenic mechanisms.

Plasma Irisin Levels in Subjects with Type 1 Diabetes: Comparison with Healthy Controls.

Irisin is a myokine that increases energy expenditure. In this cross-sectional study, we examined for differences in plasma irisin concentrations between subjects with type 1 diabetes mellitus and healthy individuals and searched for associations between plasma irisin levels and clinical and biochemical characteristics as well as self-reported physical activity. A total of 79 subjects with type 1 diabetes [age 38.2±12.5 years, men/women (n): 27/52], were consecutively recruited. Moreover, 53 healthy controls, matched for age and body mass index with those with diabetes were recruited. Plasma irisin was measured with ELISA. Participants were asked about their physical activity during the last week. We also measured trunk and visceral fat. Circulating irisin levels were lower in subjects with diabetes than in controls [median value (interquartile range): 53.0 (35.2, 106.3) vs. 178.1 (42.6, 641.6) ng/ml, respectively, p<0.001]. In the group of diabetes, univariate analysis showed that irisin levels were associated with waist circumference (beta=-0.283, p=0.023), serum triglycerides (beta=-0.282, p=0.031), and trunk fat (beta=-0.324, p=0.012). In multivariate analysis after adjustment for potential confounders, irisin levels were associated independently only with waist circumference (beta=-0.403, p=0.005). Among controls, multivariate analysis demonstrated that irisin levels were associated with pack-years of smoking (beta=-0.563, p=0.012) and fasting triglycerides (beta=-0.338, p=0.041). Circulating irisin levels were lower in subjects with diabetes in comparison with healthy-matched controls. In conclusion, plasma irisin concentrations in subjects with diabetes were associated with waist circumference, while in controls with serum triglycerides and pack-years of smoking.

Protein kinase C and cardiac dysfunction: a review.

Heart failure (HF) is a physiological state in which cardiac output is insufficient to meet the needs of the body. It is a clinical syndrome characterized by impaired ability of the left ventricle to either fill or eject blood efficiently. HF is a disease of multiple aetiologies leading to progressive cardiac dysfunction and it is the leading cause of deaths in both developed and developing countries. HF is responsible for about 73,000 deaths in the UK each year. In the USA, HF affects 5.8 million people and 550,000 new cases are diagnosed annually. Cardiac remodelling (CD), which plays an important role in pathogenesis of HF, is viewed as stress response to an index event such as myocardial ischaemia or imposition of mechanical load leading to a series of structural and functional changes in the viable myocardium. Protein kinase C (PKC) isozymes are a family of serine/threonine kinases. PKC is a central enzyme in the regulation of growth, hypertrophy, and mediators of signal transduction pathways. In response to circulating hormones, activation of PKC triggers a multitude of intracellular events influencing multiple physiological processes in the heart, including heart rate, contraction, and relaxation. Recent research implicates PKC activation in the pathophysiology of a number of cardiovascular disease states. Few reports are available that examine PKC in normal and diseased human hearts. This review describes the structure, functions, and distribution of PKCs in the healthy and diseased heart with emphasis on the human heart and, also importantly, their regulation in heart failure.

Principal Aspects Regarding the Maintenance of Mammalian Mitochondrial Genome Integrity.

Mitochondria have emerged as key players regarding cellular homeostasis not only due to their contribution regarding energy production through oxidative phosphorylation, but also due to their involvement in signaling, ion regulation, and programmed cell death. Indeed, current knowledge supports the notion that mitochondrial dysfunction is a hallmark in the pathogenesis of various diseases. Mitochondrial biogenesis and function require the coordinated action of two genomes: nuclear and mitochondrial. Unfortunately, both intrinsic and environmental genotoxic insults constantly threaten the integrity of nuclear as well as mitochondrial DNA. Despite the extensive research that has been made regarding nuclear genome instability, the importance of mitochondrial genome integrity has only recently begun to be elucidated. The specific architecture and repair mechanisms of mitochondrial DNA, as well as the dynamic behavior that mitochondria exert regarding fusion, fission, and autophagy participate in mitochondrial genome stability, and therefore, cell homeostasis.

Attenuation of post-infarction remodeling in rats by sustained myocardial growth hormone administration.

Prevention of left ventricular remodeling is an important therapeutic target post-myocardial infarction. Experimentally, treatment with growth hormone (GH) is beneficial, but sustained local administration has not been thoroughly investigated. We studied 58 rats (322 ± 4 g). GH was administered via a biomaterial-scaffold, following in vitro and in vivo evaluation of degradation and drug-release curves. Treatment consisted of intra-myocardial injection of saline or alginate-hydrogel, with or without GH, 10 min after permanent coronary artery ligation. Echocardiographic and histologic remodeling-indices were examined 3 weeks post-ligation, followed by immunohistochemical evaluation of angiogenesis, collagen, macrophages and myofibroblasts. GH-release completed at 3 days and alginate-degradation at ∼7 days. Alginate + GH consistently improved left ventricular end-diastolic and end-systolic diameters, ventricular sphericity, wall tension index and infarct-thickness. Microvascular-density and myofibroblast-count in the infarct and peri-infarct areas were higher after alginate + GH. Macrophage-count and collagen-content did not differ between groups. Early, sustained GH-administration enhances angiogenesis and myofibroblast-activation and ameliorates post-infarction remodeling.

Translating thyroid hormone effects into clinical practice: the relevance of thyroid hormone receptor α1 in cardiac repair.

Thyroid hormone (TH) appears to have a critical role in cardiac repair after injury beyond its role in development and metabolism homeostasis. This unique action is due to the fact that TH effect on the heart is shown to be differentiated depending on its administration on injured or healthy myocardium. Thus, TH can limit ischemia-reperfusion injury via a fine balance between pro-apoptotic and pro-survival signaling pathways. This response is thyroid hormone receptor (TRα1) dependent. Furthermore, an interaction between stress-induced growth kinase signaling and TRα1 is shown to occur and determine postischemic remodeling and cardiac recovery depending on the availability of TH. This new evidence is consistent with clinical observations showing the cardioprotective effect of TH treatment in cardiac surgery, transplantation and heart failure. TH and/or thyroid analogs may be novel agents in treating heart diseases.

Translating thyroid hormone into clinical practice: lessons learned from the post-hoc analysis on data available from the ThyRepair study.

Background: Thyroid hormone (TH) appears to have a reparative action on the postinfarcted myocardium. This novel action was recently tested in a pilot, randomized, double-blind, placebo-controlled trial (ThyRepair). The present study performed a post-hoc analysis of data from the ThyRepair study to provide further insights into the novel actions of TH on the human postischemic myocardium. Methods: Data from 41 patients participating in the ThyRepair study (n = 20 placebo and n = 21 LT3) were included in the analysis. LT3 treatment started after stenting and continued intravenously for 48 h. All patients had cardiac magnetic resonance (CMR) at hospital discharge; left ventricular (LV) ejection fraction (LVEF%), LV end-diastolic volume index (LVEDVi; mL/m2), LV end-systolic volume index (LVESVi; mL/m2), infarct volume (IV), left ventricular mass index (LVMi) as edema index, and microvascular obstruction (MVO) were assessed. Patients were divided into two groups based on the median value of the IV: patients with IV ≤ 20% of the LV (group A) and patients with IV > 20% (group B). CMR measurements at discharge are expressed as mean ± SD. Results: In group A, the placebo and T3-treated groups had similar LVEF% (56.8 ± 10.2 vs. 52.2 ± 10.5), LVEDVi (90.9 ± 19.8 vs. 92.8 ± 14.5), and LVESVi (40.8 ± 18.2 vs. 44.9 ± 14.1) at discharge. In group B, LVEDVi and LVESVi were 112 ± 23.8 and 68.3 ± 21.5 for placebo vs. 91.8 ± 18.6 and 49.0 ± 14.0 for the T3-treated group, respectively, p < 0.05. LVEF% was significantly increased in the T3-treated group vs. placebo, 47.3 ± 6.5 vs. 39.9 ± 8.7, p < 0.05. In group B, CMR LVMi was lower in T3-treated patients vs. placebo but did not reach statistical significance (p = 0.1). MVO was 1.95 ± 2.2 in placebo vs. 0.84 ± 0.9 in the LT3-treated group, p = 0.15. Conclusion: The present study suggests that acute LT3 treatment may exert more favorable effects on the recovery of cardiac function in patients with large infarct size. Furthermore, it signals a potential effect of LT3 on myocardial edema and microvascular obstruction. These novel findings merit further investigation in large trials.

Inhibition of thyroid hormone receptor α1 impairs post-ischemic cardiac performance after myocardial infarction in mice.

Thyroid hormone receptor α1 (TRα1) is shown to be critical for the maturation of cardiomyocytes and for the cellular response to stress. TRα1 is altered during post ischemic cardiac remodeling but the physiological significance of this response is not fully understood. Thus, the present study explored the potential consequences of selective pharmacological inhibition of TRα1 on the mechanical performance of the post-infarcted heart. Acute myocardial infarction was induced in mice (AMI), while sham operated animals served as controls (SHAM). A group of mice was treated with debutyl-dronedarone (DBD), a selective TRα1 inhibitor (AMI-DBD). AMI resulted in low T3 levels in plasma and in down-regulation of TRα1 and TRß1 expression. Left ventricular ejection fraction (LVEF%) was significantly reduced in AMI [33 (SEM 2.1) vs 79(2.5) in SHAM, p < 0.05] and was further declined in AMI-DBD [22(1.1) vs 33(2.1), respectively, p < 0.05]. Cardiac mass was increased in AMI but not in AMI-DBD hearts, resulting in significant increase in wall tension index. This increase in wall stress was accompanied by marked activation of p38 MAPK, a kinase that is sensitive to mechanical stretch and exerts negative inotropic effect. Furthermore, AMI resulted in ß-myosin heavy chain overexpression and reduction in the ratio of SR(Ca)ATPase to phospholamban (PLB). The latter further declined in AMI-DBD mainly due to increased expression of PLB. AMI induces downregulation of thyroid hormone signaling and pharmacological inhibition of TRα1 further depresses post-ischemic cardiac function. p38 MAPK and PLB may, at least in part, be involved in this response.

Thyroid Hormone and Heart Failure: Charting Known Pathways for Cardiac Repair/Regeneration.

Heart failure affects more than 64 million people worldwide, having a serious impact on their survival and quality of life. Exploring its pathophysiology and molecular bases is an urgent need in order to develop new therapeutic approaches. Thyroid hormone signaling, evolutionarily conserved, controls fundamental biological processes and has a crucial role in development and metabolism. Its active form is L-triiodothyronine, which not only regulates important gene expression by binding to its nuclear receptors, but also has nongenomic actions, controlling crucial intracellular signalings. Stressful stimuli, such as acute myocardial infarction, lead to changes in thyroid hormone signaling, and especially in the relation of the thyroid hormone and its nuclear receptor, which are associated with the reactivation of fetal development programmes, with structural remodeling and phenotypical changes in the cardiomyocytes. The recapitulation of fetal-like features of the signaling may be partially an incomplete effort of the myocardium to recapitulate its developmental program and enable cardiomyocytes to proliferate and finally to regenerate. In this review, we will discuss the experimental and clinical evidence about the role of the thyroid hormone in the recovery of the myocardium in the setting of heart failure with reduced and preserved ejection fraction and its future therapeutic implications.

Endothelin Modulates Rhythm Disturbances and Autonomic Responses to Acute Emotional Stress in Rats.

The ubiquitous peptide endothelin is currently under investigation as a modulatory factor of autonomic responses to acute emotional stress. Baseline plasma levels of endothelin alter blood pressure responses, but it remains unclear whether autonomic activity and arrhythmogenesis (i.e., brady- or tachyarrhythmias) are affected. We recorded sympathetic and vagal indices (derived from heart rate variability analysis), rhythm disturbances, voluntary motion, and systolic blood pressure after acute emotional stress in conscious rats with implanted telemetry devices. Two strains were compared, namely wild-type and ETB-deficient rats, the latter displaying elevated plasma endothelin. No differences in heart rate or blood pressure were evident, but sympathetic responses were blunted in ETB-deficient rats, contrasting prompt activation in wild-type rats. Vagal withdrawal was observed in both strains at the onset of stress, but vagal activity was subsequently restored in ETB-deficient rats, accompanied by low voluntary motion during recovery. Reflecting such distinct autonomic patterns, frequent premature ventricular contractions were recorded in wild-type rats, as opposed to sinus pauses in ETB-deficient rats. Thus, chronically elevated plasma endothelin levels blunt autonomic responses to acute emotional stress, resulting in vagal dominance and bradyarrhythmias. Our study provides further insights into the pathophysiology of stress-induced tachyarrhythmias and syncope.

Dose-dependent effects of thyroid hormone on post-ischemic cardiac performance: potential involvement of Akt and ERK signalings.

The present study explored the effects of thyroid hormone (TH) treatment on post-ischemic cardiac function and potential implicated mechanisms. Acute myocardial infarction (AMI) was induced in mice by coronary artery ligation while sham-operated animals served as controls. This procedure resulted in a marked depression of cardiac function and significant reduction in TH levels in plasma. TH was given at a dose aiming to normalize T3 levels in plasma [AMI-TH (A)] and also at higher doses. The group of animals treated with the highest dose of TH, which displayed significantly increased mortality rate was included in the study [AMI-TH (B)]. In AMI-TH (A) mice, TH significantly improved left ventricular (LV) ejection fraction (EF%), [27.9% (1.4) in AMI versus 38.0 (3.1) in AMI-TH (A), P < 0.05], and favorably remodeled LV chamber while α-MHC was the dominant isoform expressed. In AMI-TH (B) mice, TH treatment resulted in increased mortality as compared to untreated mice (73% vs 47%, P < 0.05), while the favorable effect of TH was not evident in the survived animals. At the molecular level, TH, at the replacement dose, modestly increased p-Akt levels in the myocardium without any change in p-ERK levels. On the contrary, TH at the higher dose resulted in further increase in p-Akt along with an increase in p-ERK levels. In conclusion, TH appears to have a dose-dependent bimodal effect on post-ischemic cardiac performance and this effect may, at least in part, be mediated by a distinct pattern of activation of Akt and ERK signaling.

Thyroid hormone and cardiac repair/regeneration: from Prometheus myth to reality?

Nature's models of repair and (or) regeneration provide substantial evidence that a natural healing process may exist in the heart. The potential for repair and (or) regeneration has been evolutionarily conserved in mammals, and seems to be restricted to the early developmental stages. This window of regeneration is reactivated during the disease state in which fetal gene reprogramming occurs in response to stress. Analogies exist between the damaged and developing heart, indicating that a regulatory network that drives embryonic heart development may control aspects of heart repair and (or) regeneration. In this context, thyroid hormone (TH), which is a critical regulator of the maturation of the myocardium, appears to have a reparative role later in adult life. Changes in TH - thyroid hormone receptor (TR) homeostasis govern the return of the injured myocardium to the fetal phenotype. Accordingly, TH can induce cardiac repair and (or) regeneration by reactivating developmental gene programming. As a proof of concept in humans, TH is found to be an independent determinant of functional recovery and mortality after myocardial infarction. The potential of TH to regenerate and (or) repair the ischemic myocardium is now awaited to be tested in clinical trials.

Mathieu Joseph Bonaventure Orfila (1787-1853): The Founder of Modern Toxicology.

Mateu Joseph Bonaventura Orfila i Rotger was a prominent Spanish chemist and scholar of the 19th century whose experimental work has enormously contributed to the progress of toxicology. Being a pioneer with his research on the effects of toxins and antidotes on live animals, he established basic principles of modern medicine and pharmacology. Orfila improved the accuracy of several chemical techniques such as the Marsh test. He served as an expert and well-known scientific investigator in important legal trials involving alleged poisonings with arsenic and other chemical substances. In 1840, he was asked to investigate the notorious case of Charles Lafarge's death, whose wife had been accused with murder by poisoning his food with arsenic. After four failed chemical analyses, Orfila was finally able to detect arsenic in the victim's body, leading the court to convict Madame Lafarge. Due to his overall contribution to the field, Orfila is considered the father of modern toxicology.

Assessment of frailty and related outcomes in older patients with heart failure: A cohort study.

OBJECTIVE: Heart failure (HF) is a common cause of morbidity and mortality in older patients. Frailty is prevalent and complicates the course of HF. We sought to investigate the impact of frailty on HF outcomes. METHODS: Patients over 65 years old hospitalized with acute decompensated HF and mildly reduced or preserved EF, between September 2017 and September 2019 were enrolled in the study. Before hospital discharge at euvolemic state, patients underwent six-minute walk test (6MWT) and frailty assessment using FRIED and modified SOF scores. Predictors of death, readmissions, and increase in diuretic dose were analyzed by multivariable logistic regression models. RESULTS: We enrolled 193 consecutive patients (mean age 78.6 ± 8.4 years, 29.5% males, 59.6% with HF and preserved EF). All patients had at least one comorbidity (40.9% coronary artery disease, 71% diabetes, and 86% hypertension). The mean 6MWT distance was 316.2 meters. According to FRIED score, 4.7% were normal and 17.6% were categorized as pre-frail and 77.7% as frail, while according to SOF index 9.8% were normal, 15% were categorized as pre-frail and 75.1% as frail. Frail patients according to both indices had a higher risk of 90-day readmissions, uptitration of diuretics within 90 days (p < 0.001 for both) and numerically but not significantly higher risk of death. Frailty status was independently associated with higher risk of 90-day readmissions, uptitration of diuretics, and higher BNP at 90 days. CONCLUSIONS: Frailty in older patients with HF is common and associated with worse prognosis. Pre-discharge frailty assessment may aid in identification of patients at high-risk for short-term complications.