6PPD induced cardiac dysfunction in zebrafish associated with mitochondrial damage and inhibition of autophagy processes.

The compound 6PPD is widely acknowledged for its antioxidative properties; however, concerns regarding its impact on aquatic organisms have spurred comprehensive investigations. In our study, we advanced our comprehension by revealing that exposure to 6PPD could induce cardiac dysfunction, myocardial injury and DNA damage in adult zebrafish. Furthermore, our exploration unveiled that the exposure of cardiomyocytes to 6PPD resulted in apoptosis and mitochondrial injury, as corroborated by analyses using transmission electron microscopy and flow cytometry. Significantly, our study demonstrated the activation of the autophagy pathway in both the heart of zebrafish and cardiomyocytes, as substantiated by transmission electron microscopy and immunofluorescent techniques. Importantly, the increased the expression of P62 in the heart and cardiomyocytes suggested an inhibition of the autophagic process. The reduction in autophagy flux was also verified through in vivo experiments involving the infection of mCherry-GFP-LC3. We further identified that the fusion of autophagosomes and lysosomes was impaired in the 6PPD treatment group. In summary, our findings indicated that the impaired fusion of autophagosomes and lysosomes hampered the autophagic degradation process, leading to apoptosis and ultimately resulting in cardiac dysfunction and myocardial injury. This study discovered the crucial role of the autophagy pathway in regulating 6PPD-induced cardiotoxicity. SYNOPSIS: 6PPD exposure inhibited the autophagic degradation process and induced mitochondrial injury and apoptosis in the heart of adult zebrafish.

Acute exposure to tris(2,4-di-tert-butylphenyl)phosphate elicits cardiotoxicity in zebrafish (Danio rerio) larvae via inducing ferroptosis.

Tris(2,4-di-tert-butylphenyl)phosphate (AO168 =O), a novel organophosphate ester, is prevalent and abundant in the environment, posing great exposure risks to ecological and public health. Nevertheless, the toxicological effects of AO168 =O remain entirely unknown to date. The results in this study indicated that acute exposure to AO168 =O at 10 and 100 µg/L for 5 days obviously impaired cardiac morphology and function of zebrafish larvae, as proofed by decreased heartbeat, stroke volume, and cardiac output and the occurrence of pericardial edema and ventricular hypertrophy. Transcriptomics, polymerase chain reaction, and molecular docking revealed that the strong interaction of AO168 =O and transferrin receptor 1 activated the transportation of ferric iron into intracellular environment. The release of free ferrous ion to cytoplasmic iron pool also contributed to the iron overload in heart region, thus inducing ferroptosis in larvae via generation of excessive reactive oxygen species, glutathione peroxidase 4 inhibition, glutathione depletion and lipid peroxidation. Ferroptosis inhibitor (Fer-1) co-exposure effectively relieved the cardiac dysfunctions of zebrafish, verifying the dominant role of ferroptosis in the cardiotoxicity caused by AO168 =O. This research firstly reported the adverse impact and associated mechanisms of AO168 =O in cardiomyogenesis of vertebrates, underlining the urgency of concerning the health risks of AO168 =O.

3-Methyl-phenanthrene (3-MP) disrupts the electrical and contractile activity of the heart of the polar fish, navaga cod (Eleginus nawaga).

Alkylated polycyclic aromatic hydrocarbons are abundant in crude oil and are enriched during petroleum refinement but knowledge of their cardiotoxicity remains limited. Polycyclic aromatic hydrocarbons (PAHs) are considered the main hazardous components in crude oil and the tricyclic PAH phenanthrene has been singled out for its direct effects on cardiac tissue in mammals and fish. Here we test the impact of the monomethylated phenanthrene, 3-methylphenanthrene (3-MP), on the contractile and electrical function of the atrium and ventricle of a polar fish, the navaga cod (Eleginus nawaga). Using patch-clamp electrophysiology in atrial and ventricular cardiomyocytes we show that 3-MP is a potent inhibitor of the delayed rectifier current IKr (IC50 = 0.25 µM) and prolongs ventricular action potential duration. Unlike the parent compound phenanthrene, 3-MP did not reduce the amplitude of the L-type Ca2+ current (ICa) but it accelerated current inactivation thus reducing charge transfer across the myocyte membrane and compromising pressure development of the whole heart. 3-MP was a potent inhibitor (IC50 = 4.7 µM) of the sodium current (INa), slowing the upstroke of the action potential in isolated cells, slowing conduction velocity across the atrium measured with optical mapping, and increasing atrio-ventricular delay in a working whole heart preparation. Together, these findings reveal the strong cardiotoxic potential of this phenanthrene derivative on the fish heart. As 3-MP and other alkylated phenanthrenes comprise a large fraction of the PAHs in crude oil mixtures, these findings are worrisome for Arctic species facing increasing incidence of spills and leaks from the petroleum industry. 3-MP is also a major component of polluted air but is not routinely measured. This is also of concern if the hearts of humans and other terrestrial animals respond to this PAH in a similar manner to fish.

Functional abilities, respiratory and cardiac function in a large cohort of adults with Duchenne muscular dystrophy treated with glucocorticoids.

BACKGROUND AND PURPOSE: The transition to adult services, and subsequent glucocorticoid management, is critical in adults with Duchenne muscular dystrophy. This study aims (1) to describe treatment, functional abilities, respiratory and cardiac status during transition to adulthood and adult stages; and (2) to explore the association between glucocorticoid treatment after loss of ambulation (LOA) and late-stage clinical outcomes. METHODS: This was a retrospective single-centre study on individuals with Duchenne muscular dystrophy (≥16 years old) between 1986 and 2022. Logistic regression, Cox proportional hazards models and survival analyses were conducted utilizing data from clinical records. RESULTS: In all, 112 individuals were included. Mean age was 23.4 ± 5.2 years and mean follow-up was 18.5 ± 5.5 years. At last assessment, 47.2% were on glucocorticoids; the mean dose of prednisone was 0.38 ± 0.13 mg/kg/day and of deflazacort 0.43 ± 0.16 mg/kg/day. At age 16 years, motor function limitations included using a manual wheelchair (89.7%), standing (87.9%), transferring from a wheelchair (86.2%) and turning in bed (53.4%); 77.5% had a peak cough flow <270 L/min, 53.3% a forced vital capacity percentage of predicted <50% and 40.3% a left ventricular ejection fraction <50%. Glucocorticoids after LOA reduced the risk and delayed the time to difficulties balancing in the wheelchair, loss of hand to mouth function, forced vital capacity percentage of predicted <30% and forced vital capacity <1 L and were associated with lower frequency of left ventricular ejection fraction <50%, without differences between prednisone and deflazacort. Glucocorticoid dose did not differ by functional, respiratory or cardiac status. CONCLUSION: Glucocorticoids after LOA preserve late-stage functional abilities, respiratory and cardiac function. It is suggested using functional abilities, respiratory and cardiac status at transition stages for adult services planning.

Exposure to emissions generated by 3-dimensional printing with polycarbonate: effects on peripheral vascular function, cardiac vascular morphology and expression of markers of oxidative stress in male rat cardiac tissue.

Three-dimensional (3D) printing with polycarbonate (PC) plastic occurs in manufacturing settings, homes, and schools. Emissions generated during printing with PC stock and bisphenol-A (BPA), an endocrine disrupter in PC, may induce adverse health effects. Inhalation of 3D printer emissions, and changes in endocrine function may lead to cardiovascular dysfunction. The goal of this study was to determine whether there were any changes in markers of peripheral or cardiovascular dysfunction in animals exposed to PC-emissions. Male Sprague Dawley rats were exposed to PC-emissions generated by 3D printing for 1, 4, 8, 15 or 30 d. Exposure induced a reduction in the expression of the antioxidant catalase (Cat) and endothelial nitric oxide synthase (eNos). Endothelin and hypoxia-induced factor 1α transcripts increased after 30 d. Alterations in transcription were associated with elevations in immunostaining for estrogen and androgen receptors, nitrotyrosine, and vascular endothelial growth factor in cardiac arteries of PC-emission exposed animals. There was also a reduction eNOS immunostaining in cardiac arteries from rats exposed to PC-emissions. Histological analyses of heart sections revealed that exposure to PC-emissions resulted in vasoconstriction of cardiac arteries and thickening of the vascular smooth muscle wall, suggesting there was a prolonged vasoconstriction. These findings are consistent with studies showing that inhalation 3D-printer emissions affect cardiovascular function. Although BPA levels in animals were relatively low, exposure-induced changes in immunostaining for estrogen and androgen receptors in cardiac arteries suggest that changes in the action of steroid hormones may have contributed to the alterations in morphology and markers of cardiac function.

Early life stage exposure to fenbuconazole causes multigenerational cardiac developmental defects in zebrafish and potential reasons.

With the increasing use of triazole fungicides in agriculture, triazole pesticides have aroused great concern about their toxicity and ecological risk. The current study investigated the impairments of embryonic exposure to fenbuconazole (FBZ) on cardiac transgenerational toxicity and related mechanisms. The fertilized eggs were exposed to 5, 50 and 500 ng/L FBZ for 72 h, and the larvae were then raised to adulthood in clean water. The adult fish were mated with unexposed fish to produce maternal and paternal F1 and F2 embryos, respectively. The results showed that increased arrhythmia were observed in F0, F1 and F2 larvae. Transcriptome sequencing indicated that the pathway of adrenergic signaling in cardiomyocytes was enriched in F0 and F2 larvae. In both F0 and F1 adult zebrafish hearts, ADRB2 protein expression decreased, and transcription of genes related to cardiac development and Ca2+ homeostasis was downregulated. These alterations might cause cardiac developmental defects. Significantly decreased protein levels of H3K9Ac and H3K14Ac might be linked with the downregulation in transcription of cardiac development genes. Protein‒protein interaction analysis exhibited that the pathway affecting the heart was well inherited in the paternal line. These results provide new ideas for the analysis and prevention of congenital heart disease.

ß-Adrenergic signaling drives structural and functional maturation of mouse cardiomyocytes.

Cardiac maturation represents the last phase of heart development and is characterized by morphofunctional alterations that optimize the heart for efficient pumping. Its understanding provides important insights into cardiac regeneration therapies. Recent evidence implies that adrenergic signals are involved in the regulation of cardiac maturation, but the mechanistic underpinnings involved in this process are poorly understood. Herein, we explored the role of ß-adrenergic receptor (ß-AR) activation in determining structural and functional components of cardiomyocyte maturation. Temporal characterization of tyrosine hydroxylase and norepinephrine levels in the mouse heart revealed that sympathetic innervation develops during the first 3 wk of life, concurrent with the rise in ß-AR expression. To assess the impact of adrenergic inhibition on maturation, we treated mice with propranolol, isolated cardiomyocytes, and evaluated morphofunctional parameters. Propranolol treatment reduced heart weight, cardiomyocyte size, and cellular shortening, while it increased the pool of mononucleated myocytes, resulting in impaired maturation. No changes in t-tubules were observed in cells from propranolol mice. To establish a causal link between ß-AR signaling and cardiomyocyte maturation, mice were subjected to sympathectomy, followed or not by restoration with isoproterenol treatment. Cardiomyocytes from sympathectomyzed mice recapitulated the salient immaturity features of propranolol-treated mice, with the additional loss of t-tubules. Isoproterenol rescued the maturation deficits induced by sympathectomy, except for the t-tubule alterations. Our study identifies the ß-AR stimuli as a maturation promoting signal and implies that this pathway can be modulated to improve cardiac regeneration therapies.NEW & NOTEWORTHY Maturation involves a series of morphofunctional alterations vital to heart development. Its regulatory mechanisms are only now being unveiled. Evidence implies that adrenergic signaling regulates cardiac maturation, but the mechanisms are poorly understood. To address this point, we blocked ß-ARs or performed sympathectomy followed by rescue experiments with isoproterenol in neonatal mice. Our study identifies the ß-AR stimuli as a maturation signal for cardiomyocytes and highlights the importance of this pathway in cardiac regeneration therapies.

Effect of modified citrus pectin on galectin-3 inhibition in cisplatin-induced cardiac and renal toxicity.

This study evaluated the effect of pharmacological inhibition of galectin 3 (Gal-3) with modified citrus pectin (MCP) on the heart and kidney in a model of cisplatin-induced acute toxicity. Male Wistar rats were divided into four groups (n = 6/group): SHAM, which received sterile saline intraperitoneally (i.p.) for three days; CIS, which received cisplatin i.p. (10 mg/kg/day) for three days; MCP, which received MCP orally (100 mg/kg/day) for seven days, followed by sterile saline i.p. for three days; MCP+CIS, which received MCP orally for seven days followed by cisplatin i.p. for three days. The blood, heart, and kidneys were collected six hours after the last treatment. MCP treatment did not change Gal-3 protein levels in the blood and heart, but it did reduce them in the kidneys of the MCP groups compared to the SHAM group. While no morphological changes were evident in the cardiac tissue, increased malondialdehyde (MDA) levels and deregulation of the mitochondrial oxidative phosphorylation system were observed in the heart homogenates of the MCP+CIS group. Cisplatin administration caused acute tubular degeneration in the kidneys; the MCP+CIS group also showed increased MDA levels. In conclusion, MCP therapy in the acute model of cisplatin-induced toxicity increases oxidative stress in cardiac and renal tissues. Further investigations are needed to determine the beneficial and harmful roles of Gal-3 in the cardiorenal system since it can act differently in acute and chronic diseases/conditions.

Methylglyoxal induces cardiac dysfunction through mechanisms involving altered intracellular calcium handling in the rat heart.

Methylglyoxal (MGO) is an endogenous, highly reactive dicarbonyl metabolite generated under hyperglycaemic conditions. MGO plays a role in developing pathophysiological conditions, including diabetic cardiomyopathy. However, the mechanisms involved and the molecular targets of MGO in the heart have not been elucidated. In this work, we studied the exposure-related effects of MGO on cardiac function in an isolated perfused rat heart ex vivo model. The effect of MGO on calcium homeostasis in cardiomyocytes was studied in vitro by the fluorescence indicator of intracellular calcium Fluo-4. We demonstrated that MGO induced cardiac dysfunction, both in contractility and diastolic function. In rat heart, the effects of MGO treatment were significantly limited by aminoguanidine, a scavenger of MGO, ruthenium red, a general cation channel blocker, and verapamil, an L-type voltage-dependent calcium channel blocker, demonstrating that this dysfunction involved alteration of calcium regulation. MGO induced a significant concentration-dependent increase of intracellular calcium in neonatal rat cardiomyocytes, which was limited by aminoguanidine and verapamil. These results suggest that the functionality of various calcium channels is altered by MGO, particularly the L-type calcium channel, thus explaining its cardiac toxicity. Therefore, MGO could participate in the development of diabetic cardiomyopathy through its impact on calcium homeostasis in cardiac cells.

The effect of glucagon-like peptide-1 receptor agonists on cardiac function and structure in patients with or without type 2 diabetes mellitus: An updated systematic review and meta-analysis.

AIMS: To conduct an updated systematic review and meta-analysis to evaluate the efficacy of glucagon-like peptide-1 receptor agonists (GLP-1RAs) with regard to cardiac function and structure in people with or without type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: We conducted a systematic search using the PubMed, Embase and ClinicalTrials.gov online databases. The primary outcome of interest was changes in mitral inflow E-velocity to tissue Doppler e' velocity (E/e') ratio. Secondary outcomes included other indicators of cardiac reverse remodelling and functional capacity comprising changes in left ventricular mass (LVM), left ventricular global longitudinal strain, left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular ejection fraction (LVEF), early to atrial mitral inflow velocity ratio, left atrial volume (LAV), N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels and 6-min walk test (6MWT) results. RESULTS: A total of 15 trials involving 898 patients were included in this analysis. GLP-1RAs significantly improved E/e' ratio (mean difference [MD] = -0.73; 95% confidence interval [CI] -1.34, -0.13), LVM (MD = -3.86 g; 95% CI -7.60, -0.12), LAV (MD = -8.20 mL; 95% CI -12.37, -4.04), NT-proBNP level (standardized MD = -0.27; 95% CI -0.47, -0.06), and 6MWT result (MD = +22.31 m; 95% CI 1.64, 42.99). However, GLP-1RAs had no effect on LVEF (MD = +0.31%; 95% CI -1.02, 1.64). CONCLUSIONS: In this systematic review and meta-analysis, GLP-1RAs were found to have a positive impact on left ventricle diastolic function, hypertrophy, and exercise capacity, but had no effect on systolic function.

CYP2J2-mediated metabolism of arachidonic acid in heart: A review of its kinetics, inhibition and role in heart rhythm control.

Cytochrome P450 2 J2 (CYP2J2) is primarily expressed extrahepatically and is the predominant epoxygenase in human cardiac tissues. This highlights its key role in the metabolism of endogenous substrates. Significant scientific interest lies in cardiac CYP2J2 metabolism of arachidonic acid (AA), an omega-6 polyunsaturated fatty acid, to regioisomeric bioactive epoxyeicosatrienoic acid (EET) metabolites that show cardioprotective effects including regulation of cardiac electrophysiology. From an in vitro perspective, the accurate characterization of the kinetics of CYP2J2 metabolism of AA including its inhibition and inactivation by drugs could be useful in facilitating in vitro-in vivo extrapolations to predict drug-AA interactions in drug discovery and development. In this review, background information on the structure, regulation and expression of CYP2J2 in human heart is presented alongside AA and EETs as its endogenous substrate and metabolites. The in vitro and in vivo implications of the kinetics of this endogenous metabolic pathway as well as its perturbation via inhibition and inactivation by drugs are elaborated. Additionally, the role of CYP2J2-mediated metabolism of AA to EETs in cardiac electrophysiology will be expounded.

Chronic nicotine exposure is associated with electrophysiological and sympathetic remodeling in the intact rabbit heart.

Nicotine is the primary addictive component of tobacco products. Through its actions on the heart and autonomic nervous system, nicotine exposure is associated with electrophysiological changes and increased arrhythmia susceptibility. To assess the underlying mechanisms, we treated rabbits with transdermal nicotine (NIC, 21 mg/day) or control (CT) patches for 28 days before performing dual optical mapping of transmembrane potential (RH237) and intracellular Ca2+ (Rhod-2 AM) in isolated hearts with intact sympathetic innervation. Sympathetic nerve stimulation (SNS) was performed at the first to third thoracic vertebrae, and ß-adrenergic responsiveness was additionally evaluated following norepinephrine (NE) perfusion. Baseline ex vivo heart rate (HR) and SNS stimulation threshold were higher in NIC versus CT (P = 0.004 and P = 0.003, respectively). Action potential duration alternans emerged at longer pacing cycle lengths (PCL) in NIC versus CT at baseline (P = 0.002) and during SNS (P = 0.0003), with similar results obtained for Ca2+ transient alternans. SNS shortened the PCL at which alternans emerged in CT but not in NIC hearts. NIC-exposed hearts tended to have slower and reduced HR responses to NE perfusion, but ventricular responses to NE were comparable between groups. Although fibrosis was unaltered, NIC hearts had lower sympathetic nerve density (P = 0.03) but no difference in NE content versus CT. These results suggest both sympathetic hypoinnervation of the myocardium and regional differences in ß-adrenergic responsiveness with NIC. This autonomic remodeling may contribute to the increased risk of arrhythmias associated with nicotine exposure, which may be further exacerbated with long-term use.NEW & NOTEWORTHY Here, we show that chronic nicotine exposure was associated with increased heart rate, increased susceptibility to alternans, and reduced sympathetic electrophysiological responses in the intact rabbit heart. We suggest that this was due to sympathetic hypoinnervation of the myocardium and diminished ß-adrenergic responsiveness of the sinoatrial node following nicotine treatment. Though these differences did not result in increased arrhythmia propensity in our study, we hypothesize that prolonged nicotine exposure may exacerbate this proarrhythmic remodeling.

Renal and cardiac effects of the PDE9 inhibitor BAY 73-6691 in 5/6 nephrectomized rats.

It has been suggested that the novel selective phosphodiesterase 9 (PDE9) inhibitor may improve cardiac and renal function by blocking 3',5'-cyclic guanosine monophosphate (cGMP) degradation. 5/6 nephrectomized (5/6Nx) rats were used to investigate the effects of the PDE9 inhibitor (BAY 73-6691) on the heart and kidney. Two doses of BAY 73-6691 (1 mg/kg/day and 5 mg/kg/day) were given for 95 days. The 5/6Nx rats developed albuminuria, a decrease in serum creatinine clearance (Ccr), and elevated serum troponin T levels. Echocardiographic data showed that 5/6 nephrectomy resulted in increased fractional shortening (FS), stroke volume (SV), and left ventricular ejection fraction (EF). However, 95 days of PDE9 inhibitor treatment did not improve any cardiac and renal functional parameter. Histopathologically, 5/6 nephrectomy resulted in severe kidney and heart damage, such as renal interstitial fibrosis, glomerulosclerosis, and enlarged cardiomyocytes. Telmisartan attenuated renal interstitial fibrosis and glomerulosclerosis as well as improved cardiomyocyte size. However, except for cardiomyocyte size and renal perivascular fibrosis, BAY 73-6691 had no effect on other cardiac and renal histologic parameters. Pathway enrichment analysis using RNA sequencing data of kidney and heart tissue identified chronic kidney disease pathways, such as phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt) signaling pathway, complement and coagulation cascades, and nuclear factor kappa B (NF-κB) signaling pathway. PDE9i did not affect any of these disease-related pathways. Two dosages of the PDE9 inhibitor BAY 73-6691 known to be effective in other rat models have only limited cardio-renal protective effects in 5/6 nephrectomized rats.

Role and mechanism of miR-871-3p/Megf8 in regulating formaldehyde-induced cardiomyocyte inflammation and congenital heart disease.

OBJECTIVE AND DESIGN: We aimed to investigate the molecular mechanism underlying formaldehyde (FA)-induced congenital heart disease (CHD) using in vitro and in vivo models. MATERIALS AND SUBJECTS: Neonatal rat heart tissues and H9C2 cells were used for in vitro studies, while FA-exposed new-born rats were used for in vivo studies. TREATMENT: H9C2 cells were exposed to FA concentrations of 0, 50, 100 and 150 µM/mL for 24 h. METHODS: Whole transcriptome gene sequencing identified differentially expressed miRNAs in neonatal rat heart tissues, while Real-time quantitative PCR (RT-qPCR) assessed miR-871-3p and Megf8 expression. RNA pull-down and dual-luciferase reporter assays determined miR-871-3p and Megf8 relationships. Inflammatory cytokine expression was assessed by western blotting. A FA-induced CHD model was used to validate miR-871-3p regulatory effects in vivo. RESULTS: We identified 89 differentially expressed miRNAs, with 28 up-regulated and 61 down-regulated (fold change ≥ 2.0, P < 0.05). Inflammation (interleukin) and signalling pathways were found to control FA-induced cardiac dysplasia. miR-871-3p was upregulated in FA-exposed heart tissues, modulated inflammation, and directly targeted Megf8. In vivo experiments showed miR-871-3p knockdown inhibited FA-induced inflammation and CHD. CONCLUSION: We demonstrated miR-871-3p's role in FA-induced CHD by targeting Megf8, providing potential targets for CHD intervention and improved diagnosis and treatment strategies.

Phlorizin, a novel caloric restriction mimetic, stimulates hypoxia and protects cardiomyocytes through activating autophagy via modulating the Hif-1α/Bnip3 axis in sepsis-induced myocardial dysfunction.

BACKGROUND: Sepsis is a systemic inflammatory syndrome that can lead to multiple organ dysfunction and life-threatening complications. Sepsis-induced myocardial dysfunction (SIMD) has been confirmed to be present in half of patients with septic shock, increasing their mortality rate to 70-90%. The pathogenesis of SIMD is complex, and no specific clinical treatment has yet been developed. Caloric restriction mimetics (CRM), compounds that simulate the biochemical and functional properties of CR, can improve cardiovascular injury by activating autophagy. This study investigated the effect of a new type of CRM which can induce hypoxia, the SGLT nonspecific inhibitor phlorizin on SIMD. MATERIALS AND METHODS: In vivo, phlorizin was administered at 1 mg/kg/day intragastrically for 28 days. In vitro, AC16 was treated with 120 µM phlorizin for 48 h. Echocardiography was used to assess cardiac function. Myocardial injury markers were detected in serum and cell supernatant. Western blotting was employed to detect changed proteins associated with apoptosis and autophagy. Immunofluorescence, immunohistochemistry, co-immunoprecipitation, molecular docking, and other methods were also used to illustrate cellular changes. RESULTS: In vivo, phlorizin significantly improved the survival rate and cardiac function after sepsis injury, reduced markers of myocardial injury, inhibited myocardial apoptosis and oxidative stress, and promoted autophagy. In vitro, phlorizin alleviated the apoptosis of AC16, as well as inhibited oxidative stress and apoptotic enzyme activity. Phlorizin acts on autophagy at multiple sites through low energy (activation of AMPK) and hypoxia (release of Beclin-1 by Hif-1α/Bnip3 axis), promoting the formation and degradation of autophagosomes. CONCLUSION: We indicated for the first time that phlorizin could inhibit glucose uptake via GLUT-1 and conforms to the metabolic characteristics of CRM, it can induce the hypoxic transcriptional paradigm. In addition, it inhibits apoptosis and improves SIMD by promoting autophagy generation and unobstructing autophagy flux. Moreover, it affects autophagy by releasing Beclin-1 through the Hif-1α/Bnip3 axis.

Development, Histological, and Ultrastructural Evaluation of Sheep Hyperimmune Serum Therapy for COVID-19 / Desarrollo, Evaluación Histológica y Ultraestructural de la Terapia con Suero Hiperinmune de Oveja para COVID-19

SUMMARY: In response to the threat posed by new variants of SARS-CoV-2 and the urgent need for effective treatments in the absence of vaccines, the aim of this study was to develop a rapid and cost-effective hyperimmune serum (HS) derived from sheep and assess its efficacy. The utilization of a halal-certified, easily maintained in certain geographic regions, easy-to-handle animal such as sheep could provide a viable alternative to the expensive option of horses. Sheep were immunized with a whole inactivated SARS-CoV- 2 antigen to produce HS, which was evaluated for neutralizing potency using the PRNT50 assay. K18-hACE2 transgenic mice (n=35) were divided into three groups: control, SARS-CoV-2 exposure through inhalation, and SARS-CoV-2 exposed mice treated with HS. HS efficacy was assessed through serum proinflammatory cytokine levels, qRT-PCR analysis, histopathological examination of lungs and hearts, and transmission electron microscopy. Purified HS exhibited significant neutralizing activity (1/24,576). The SARS-CoV-2+HS group showed lower levels of TNF-α, IL-10, and IL-6 (P<0.01) and relatively lower levels of MCP-1 compared to the SARS-CoV-2 group. HS prevented death, reduced viral RNA levels in the lungs and hearts, protected against severe interstitial pneumonia, preserved lung tissue integrity, and prevented myocyte damage, while the SARS-CoV-2 group exhibited viral presence in the lungs. This study successfully developed a sheep-derived HS against the entire SARS-CoV-2 virus, resulting in a significant reduction in infection severity, inflammation, and systemic cytokine production. The findings hold promise for treating severe COVID-19 cases, including emerging viral variants, and immunocompromised patients.

En respuesta a la amenaza que suponen las nuevas variantes del SARS-CoV-2 y la urgente necesidad de tratamientos eficaces en ausencia de vacunas, el objetivo de este estudio fue desarrollar un suero hiperinmune (HS) rápido y rentable derivado de ovejas. y evaluar su eficacia. La utilización de un animal con certificación halal, de fácil mantenimiento en determinadas regiones geográficas y de fácil manejo, como las ovejas, podría proporcionar una alternativa viable a la costosa opción de los caballos. Las ovejas fueron inmunizadas con un antígeno de SARS-CoV-2 completamente inactivado para producir HS, cuya potencia neutralizante se evaluó mediante el ensayo PRNT50. Los ratones transgénicos K18-hACE2 (n = 35) se dividieron en tres grupos: control, exposición al SARS-CoV-2 mediante inhalación y ratones expuestos al SARS-CoV-2 tratados con HS. La eficacia de HS se evaluó mediante niveles de citoquinas proinflamatorias en suero, análisis qRT-PCR, examen histopatológico de pulmones y corazones y microscopía electrónica de transmisión. El HS purificado exhibió una actividad neutralizante significativa (1/24,576). El grupo SARS-CoV-2+HS mostró niveles más bajos de TNF-α, IL-10 e IL-6 (P<0,01) y niveles relativamente más bajos de MCP-1 en comparación con el grupo SARS-CoV-2. HS evitó la muerte, redujo los niveles de ARN viral en los pulmones y el corazón, protegió contra la neumonía intersticial grave, preservó la integridad del tejido pulmonar y evitó el daño de los miocitos, mientras que el grupo SARS-CoV-2 exhibió presencia viral en los pulmones. Este estudio desarrolló con éxito un HS derivado de ovejas contra todo el virus SARS-CoV-2, lo que resultó en una reducción significativa de la gravedad de la infección, la inflamación y la producción sistémica de citocinas. Los hallazgos son prometedores para el tratamiento de casos graves de COVID- 19, incluidas las variantes virales emergentes y los pacientes inmunocomprometidos.

Erythropoietin-mediated cardioprotection in hearts subjected to ischemia reperfusion.

Several studies provide evidence that erythropoietin (EPO) could play an important role in the recovery of the heart subjected to ischemia-reperfusion. In this regard, it has been suggested that EPO could be involved in protein kinase B (Akt) activation as a cell survival protein. The aim of the present study was to investigate the effects of EPO on the Akt/glycogen synthase kinase 3 beta (GSK-3ß) pathway in the presence or absence of wortmannin (W, Akt inhibitor) and its relationship with mitochondrial morphology and function preservation in ischemic-reperfused rat hearts. EPO improved the functional recovery of the heart subjected to ischemia-reperfusion, reduced the release of CK and the infarct size, and promoted preservation of the mitochondrial structure. Moreover, it reduced tissue lactate content and preserved glycogen in order to prevent ischemia. The results showed greater Akt activation, accompanied by preservation of swelling and mitochondrial calcium retention capacity, as well as an increase in ATP synthesis capacity. These results were accompanied by an inhibition of GSK-3ß, suggesting regulation of Akt on the opening of the mitochondrial permeability transition pore. All these beneficial effects exerted by acute treatment with EPO were prevented by W. The present study provided novel evidence that EPO not only enhances intrinsic activation of Akt during myocardial ischemia-reperfusion but also promotes GSK-3ß inhibition, contributing to mitochondrial structure and function preservation.

Interleukin-37 has A Promising Cardioprotective Effect on Isoproterenol-Induced Myocardial Infarction / La Interleucina-37 tiene un Efecto Cardioprotector Prometedor sobre el Infarto de Miocardio Inducido por Isoproterenol

SUMMARY: The main cause of mortality and disability globally is myocardial infarction (MI). Isoproterenol (ISO), a β-adrenoceptor agonist, has been used to induce rat myocardial necrosis. Whereas interleukin-37 (IL-37) has anti-inflammatory and cytoprotective properties. The study aimed to investigate the potential protective effects of IL-37 administration on cardiac architecture, oxidative stress, and inflammatory markers during ISO-induced MI in rats. Three groups of adult male rats were used in this study, the normal control group (n=8), ISO-induced MI group (n=8) that received isoproterenol hydrochloride (ISO) (100 mg/kg/day, SC, for the first 2 consecutive days), and IL-37-treated group (ISO+IL-37) (n=8) that received recombinant human IL-37 (40 µg/kg /day, intraperitoneally, for 2 weeks during and after ISO injections. Heart rate (HR.) and ECG changes were monitored. Some oxidative stress markers such as superoxide dismutase (SOD), nitric oxide (NOx), malondialdehyde (MDA), and glutathione (GSH) tissue levels in the tissue homogenate were assayed. Interleukin- 6 (IL-6), tumor necrosis factor- α (TNF-α), caspase-8, P53, and C- reactive protein (CRP) were among the inflammatory markers examined. In addition, serum levels of creatinine kinase (CK-MB) and lactate dehydrogenase (LDH) were analyzed to evaluate the myocardial injury. For histological analysis, tissues were sectioned, fixed in paraffin, and stained with hematoxylin and eosin (H&E), Masson Trichrome and, immunohistochemical against NF-kB, TNF-α, and Caspase-9. IL-37 improved ECG changes, cardiac enzyme markers, and some inflammatory markers of oxidative stress in ISO-induced MI. It also improved the histopathological and immunohistochemical changes in MI. In conclusion: IL-37 might be a promising therapeutic modality in myocardial infarction.

La principal causa de mortalidad y discapacidad a nivel mundial es el infarto de miocardio (IM). El isoproterenol (ISO), un agonista de los receptores adrenérgicos β, se ha utilizado para inducir necrosis miocárdica en ratas. Mientras que la interleucina-37 (IL-37) tiene propiedades antiinflamatorias y citoprotectoras. El estudio tuvo como objetivo investigar los posibles efectos protectores de la administración de IL-37 en la arquitectura cardíaca, el estrés oxidativo y los marcadores inflamatorios durante el infarto de miocardio inducido por ISO en ratas. En este estudio se utilizaron tres grupos de ratas macho adultas, el grupo control normal (n=8), el grupo con IM inducido por ISO (n=8) que recibió clorhidrato de isoproterenol (ISO) (100 mg/kg/día, SC, durante los primeros 2 días consecutivos) y el grupo tratado con IL-37 (ISO+IL- 37) (n=8) que recibió IL-37 humana recombinante (40 µg/kg/día, por vía intraperitoneal, durante 2 semanas durante y después de las inyecciones de ISO. Se monitorearon la frecuencia cardíaca (FC) y los cambios en el ECG. Se analizaron algunos marcadores de estrés oxidativo como la superóxido dismutasa (SOD), el óxido nítrico (NOx), el malondialdehído (MDA) y los niveles tisulares de glutatión (GSH) en el homogeneizado de tejido. La interleucina-6 (IL-6), el factor de necrosis tumoral-α (TNF-α), la caspasa-8, la P53 y la proteína C reactiva (CRP) se encontraban entre los marcadores inflamatorios examinados. Se analizaron los niveles de creatinoquinasa (CK-MB) y lactato deshidrogenasa (LDH) para evaluar la lesión miocárdica; para el análisis histológico se seccionaron los tejidos, se fijaron en parafina y se tiñeron con hematoxilina y eosina (H&E), Tricromo de Masson e inmunohistoquímica contra NF-kB, TNF-α y Caspasa-9. IL-37 mejoró los cambios de ECG, los marcadores de enzimas cardíacas y algunos marcadores inflamatorios de estrés oxidativo en el IM inducido por ISO. Además mejoró los cambios histopatológicos e inmunohistoquímicos en MI. En conclusión: la IL-37 podría ser una modalidad terapéutica prometedora en el infarto de miocardio.