L-carnitine protects cardiac damage by reducing oxidative stress and inflammatory response via inhibition of tumor necrosis factor-alpha and interleukin-1beta against isoproterenol-induced myocardial infarction

Protective effects of 3, 4-dihydroxybenzoic acid on myocardial infarction induced by isoproterenol in rats

Despite considerable advances in interventions and treatment, there is a high mortality rate in patients with myocardial infarction (MI). This is the first study to investigate the protective effects of 3, 4-dihydroxybenzoic acid against isoproterenol induced MI in rats. MI was induced by isoproterenol (100-mg/kg body weight) in rats. Then, rats were treated with 3, 4-dihydroxybenzoic acid (16-mg/kg body weight) for 2 weeks. Serum creatine kinase-MB, cardiac troponin-T, cardiac troponin-I, and heart thiobarbituric acid reactive substances were significantly (p < 0.05) increased and heart superoxide dismutase and catalase activities were significantly (p < 0.05) reduced in isoproterenol-induced myocardial infarcted rats. Isoproterenol induction significantly (p < 0.05) elevated the plasma homocysteine and serum high sensitivity-C-reactive protein levels. Furthermore, an enzyme-linked immunosorbent assay, reverse transcription polymerase chain study, and immunohistochemical (IHC) staining revealed significantly (p < 0.05) elevated levels and expression of serum/myocardial nuclear factor-κB, tumor necrosis factor-alpha, interleukin-1 beta, and Interleukin-6 and significantly (p < 0.05) reduced levels/expression of serum/myocardial interleukin-10 in myocardial infarcted rats. Nevertheless, isoproterenol-induced rats treated with 3, 4-dihydroxybenzoic acid considerably (p < 0.05) attenuated all the biochemical, molecular, and IHC parameters investigated and inhibited oxidative stress and inflammation and protected the heart, through its antioxidant and anti-inflammatory mechanisms.

IL-1 signaling pathway, an important target for inflammation surrounding in myocardial infarction

Acute myocardial infarction is an important cardiovascular disease worldwide. Although the mortality rate of myocardial infarction (MI) has improved dramatically in recent years due to timely treatment, adverse remodeling of the left ventricle continues to affect cardiac function. Various immune cells are involved in this process to induce inflammation and amplification. The infiltration of inflammatory cells in the infarcted myocardium is induced by various cytokines and chemokines, and the recruitment of leukocytes further amplifies the inflammatory response. As an increasing number of clinical anti-inflammatory therapies have achieved significant success in recent years, treating myocardial infarction by targeting inflammation may become a novel therapeutic option. In particular, successful clinical trials of canakinumab have demonstrated the important role of the inflammatory factor interleukin-1 (IL-1) in atherosclerosis. Targeted IL-1 therapy may decrease inflammation levels and improve cardiac function in patients after myocardial infarction. This article reviews the complex series of responses after myocardial infarction, including the involvement of inflammatory cells and the role of cytokines and chemokines, focusing on the progression of the IL-1 family in myocardial infarction as well as the performance of current targeted therapy drugs in experiments.

Sage (Salvia officinalis) alleviates trazadone induced rat cardiotoxicity mediated via modulation of autophagy and oxidative stress

The antidepressant drug trazodone (TRZ) is commonly used for treating depression, anxiety, and insomnia, however, it causes cardiotoxicity, which is one of its limitations. The objective of this work was to investigate the impact of sage (Salvia officinalis) in rats against cardiotoxicity induced by TRZ and to investigate the mechanisms involved in its cardio-protective properties through autophagy and oxidative stress. Fifty male albino rats were split randomly into five experimental groups: control group, sage oil group (100 mg/kg), TRZ group (20 mg/kg), protective group, and curative group. Cardiac function biomarkers (aspartate aminotransferase [AST], creatine kinase-MB [CK-MB], and cardiac troponin T [cTnI]) were assessed in serum. Oxidative stress and inflammatory biomarkers in cardiac tissue (total antioxidant capacity, malondialdehyde, and tumor necrosis factor-α) were evaluated. Heart tissues were subjected to histological, immunohistochemical, and ultrastructural evaluations. DNA damage also evaluated. Significant rise in the levels of AST, CK-MB, and cTnI were observed with enhanced autophagy along with marked histopathological changes in the form of interrupted muscle fibers with wide interstitial spaces with areas of hemorrhage and extravasated blood and interstitial mononuclear cellular infiltration in TRZ group. DNA damage was also significantly increased in TRZ group. However, administration of sage in both protective and curative groups show marked improvement of the cardiac alterations. In conclusion, sage ameliorated the alterations in the heart induced by trazadone through modulation of autophagy and oxidative stress.

CAV1 Protein Encapsulated in Mouse BMSC-Derived Extracellular Vesicles Alleviates Myocardial Fibrosis Following Myocardial Infarction by Blocking the TGF-β1/SMAD2/c-JUN Axis

Extracellular vesicles (EVs) derived from mouse bone marrow mesenchymal stem cells (mBMSCs) convey the CAV1 protein, influencing the TGF-β1/SMAD2/c-JUN pathway and thus the molecular mechanisms underlying myocardial fibrosis (MF) post-myocardial infarction (MI). Through various experimental methods, including transmission electron microscopy, Nanosight analysis, Western blot, ELISA, and qRT-PCR, we isolated, purified, and identified EVs originating from mBMSCs. Bioinformatics and experimental findings show a reduced expression of CAV1 in myocardial fibrosis tissue. Furthermore, our findings suggest that mBMSC-EVs can deliver CAV1 to cardiac fibroblasts (CFs) and that silencing CAV1 in mBMSC-EVs promotes CF fibrosis. In vivo studies further corroborated these findings. In conclusion, mBMSC-EVs mitigate myocardial fibrosis in MI mice by delivering the CAV1 protein, inhibiting the TGF-β1/SMAD2/c-JUN pathway.

Comprehensive pulmonary metabolic responses to silica nanoparticles exposure in Fisher 344 rats

Silica nanoparticles (SiNPs) could induce adverse pulmonary effects, but the mechanism was not clear enough. Metabolomics is a sensitive and high-throughput approach that could investigate the intrinsic causes of adverse health effects caused by SiNPs. The current investigation represented the first in vivo metabolomics study examining the chronic pulmonary toxicity of SiNPs at a low dosage, mimicking real human exposure situation. The recovery process after the cessation of exposure was also taken into consideration. Fisher 344 rats were treated with either saline or SiNPs for 6 months. Half of the animals in each group received an additional six-month period for recovery. The findings indicated that chronic low-level exposure to SiNPs resulted in notable alterations in pulmonary metabolism of amino acids, lipids, carbohydrates, and nucleotides. SiNPs exerted an impact on various metabolites and metabolic pathways which are linked to oxidative stress, inflammation and tumorigenesis. These included but were not limited to L-carnitine, spermidine, taurine, xanthine, and glutathione metabolism. The metabolic alterations caused by SiNPs exhibited a degree of reversibility. However, the interference of SiNPs on two metabolic pathways related to tumorigenesis was observed to persist after a recovery period. The two metabolic pathways are glycerophospholipid metabolism as well as phenylalanine, tyrosine and tryptophan biosynthesis. This study elucidated the metabolic alterations induced by chronic low-level exposure to SiNPs and presented novel evidence of the chronic pulmonary toxicity and carcinogenicity of SiNPs, from a metabolomic perspective.

Potential protective effects of L-carnitine against myocardial ischemia/reperfusion injury in a rat model

Myocardial ischemia/reperfusion (I/R) injury is a growing concern for global public health. This study seeks to explore the potential protective effects of L-carnitine (LC) against heart ischemia-reperfusion injury in rats. To induce I/R injury, the rat hearts underwent a 30-min ligation of the left anterior descending coronary artery, followed by 24 h of reperfusion. We evaluated cardiac function through electrocardiography and heart rate variability (HRV) and conducted pathological examinations of myocardial structure. Additionally, the study investigated the influence of LC on myocardial apoptosis, inflammation, and oxidative stress in the context of I/R injury. The results show that pretreatment with LC led to improvements in the observed alterations in ECG waveforms and HRV parameters in the nontreated ischemic reperfusion model group, although most of these changes did not reach statistical significance. Similarly, although without a significant difference, LC reduced the levels of proinflammatory cytokines when compared to the values in the nontreated ischemic rat group. Furthermore, LC restored the reduced expressions of SOD1, SOD2, and SOD3. Additionally, LC significantly reduced the elevated Bax expressions and showed a nonsignificant increase in Bcl-2 expression, resulting in a favorable adjustment of the Bcl-2/Bax ratio. We also observed a significant enhancement in the histological appearance of cardiac muscles, a substantial reduction in myocardial fibrosis, and suppressed CD3 + cell proliferation in the ischemic myocardium. This small-scale, experimental, in vivo study indicates that LC was associated with enhancements in the pathological findings in the ischemic myocardium in the context of ischemia/reperfusion injury in this rat model. Although statistical significance was not achieved, LC exhibits potential and beneficial protective effects against I/R injury. It does so by modulating the expression of antioxidative and antiapoptotic genes, inhibiting the inflammatory response, and enhancing autonomic balance, particularly by increasing vagal tone in the heart. Further studies are necessary to confirm and elaborate on these findings.

Effect of L-carnitine in Ameliorating Lipopolysaccharide-Induced Cardiomyocyte Injury via MAPK Signaling

The present study aimed to elucidate whether L-carnitine (LC) protected H9c2 cells and its underlying mechanisms. Cell counting kit-8 (CCK-8) assay was used to evaluate cell viability. Apoptosis, cell morphology, and lactate dehydrogenase (LDH) assessment were used to prove effects of lipopolysaccharide (LPS) and LC on H9c2 cells. RT-qPCR and western blot assays were hired to evaluate the mRNA and protein expression levels, respectively. ELISA assay was performed to determine the released protein levels. Reactive oxygen species (ROS) level was evaluated by immunofluorescence and flow cytometry. LC was revealed to protect H9c2 cells against LPS-induced injury as indicated by increased cell viability, reduced apoptosis ratio and LDH level. LC treatment also reduced BAX expression as well as up-regulated Bcl-2 expression under LPS treatment. Mechanically, LC reduced oxidative stress and ameliorated the mitochondrial injury through modulating extracellular signal-regulated kinase 1/2 and c-Jun N-terminal protein kinase c-Jun N-terminal protein kinase phosphorylation levels as indicated by decreased membrane potential, increased ATP production and mtDNA expression. We found that LC ameliorates LPS-induced cardiomyocyte injury by abrogating cell apoptosis ratio, ROS levels, as well as mitochondrial dysfunction via mitogen-activated protein kinase signaling. Our findings revealed a potential drug for sepsis or LPS-induced cardiomyocyte injury.

Implication of MAPK, Lipocalin-2, and Fas in the protective action of liposomal resveratrol against isoproterenol-induced kidney injury

Background and Objective

Isoproterenol (ISO) is a non-selective β-adrenergic receptor agonist. It can be used to treat bradycardia and cardiogenic shock. Despite its usefulness, the overstimulation of β-receptors by ISO can cause "cardiorenal syndrome," a term used to describe heart and kidney damage. Resveratrol (RES), a natural polyphenol, has marked anti-inflammatory and antioxidant activities. The present work was designed to study the protective efficacy of liposomal resveratrol (L-RES) against ISO-induced kidney injury.

Materials and Methods

The kidney injury was induced in rats by administering ISO (50 mg/kg, s.c.) twice a week for 2 weeks. RES and L-RES were administered at a dose (20 mg/kg/ day, p.o.) along with ISO for 2 weeks. Inflammatory and apoptotic biomarkers were analyzed, which were validated using histochemical analysis.

Results

ISO caused renal dysfunction, which manifested as elevated urea, creatinine and uric acid, besides cystatin c and MAPK protein overexpression. In addition, ISO induced gene expression of Fas and lipocalin-2 and provoked genomic DNA fragmentation in renal tissues as compared with the control group. Histological examination confirmed morphological alterations of the kidney tissues obtained from the ISO group. Concurrent treatment of either RES or L-RES with ISO significantly ameliorated kidney damage as demonstrated by the improvement of all measured parameters with the best results for L-RES. The histopathological findings were correlated with the above biochemical parameters.

Conclusion

L-RES could be a promising approach for the prevention of kidney injury induced by ISO, most likely via the downregulation of MAPK, cystatin c, Fas, and lipocalin-2.

Anti-smoking drugs cytisine and varenicline reduce cardiac reperfusion injury in rat model of myocardial ischemia

Evidence to date indicates that activation of nicotinic acetylcholine receptors (nAChRs) can reduce cardiac injury from ischemia and subsequent reperfusion. The use of nAChR agonists in various animal models leads to a reduction in reperfusion injury. Earlier this effect was shown for the agonists of α7 nAChR subtype. In this work, we demonstrated the expression of mRNA encoding α4, α6 and β2 nAChR subunits in the left ventricle of rat heart. In a rat model of myocardial ischemia, we studied the effect of α4β2 nAChR agonists cytisine and varenicline, medicines used for the treatment of nicotine addiction, and found them to significantly reduce myocardium ischemia-reperfusion injury, varenicline manifesting a higher protection. Dihydro-β-erythroidine, antagonist of α4β2 nAChR, as well as methyllycaconitine, antagonist of α7 and α6β2-containing nAChR, prevented protective effect of varenicline. This together with the presence of α4, α6 and β2 subunit mRNA in the left ventricule of rat heart raises the possibility that the varenicline effect is mediated by α4β2 as well as by α7 and/or α6β2-containing receptors. Our results point to a new way for the use of cytisine and varenicline as cardioprotective agents.

β-caryophyllene blocks reactive oxygen species-mediated hyperlipidemia in isoproterenol-induced myocardial infarcted rats

Myocardial infarction (MI) is a leading cause of death. Lipid-lowering interventions have been shown to decrease coronary events and mortality of MI and heart failure. In this investigation, we assessed the anti-hyperlipidemic effects of β-caryophyllene in isoproterenol-induced myocardial infarcted rats. β-Caryophyllene (20 mg/kg body weight) pre-and co-treatment was given to rats orally, daily, for 3 weeks. Isoproterenol (100 mg/kg body weight) was administered to rats to induce MI. The levels of serum cardiac troponins T and I, serum and heart total cholesterol, triglycerides, free fatty acids, and the levels of serum low-density and very low-density lipoprotein-cholesterols were augmented, and the level of serum high-density lipoprotein-cholesterol was lessened in myocardial infarcted rats. Further, the activity/levels of liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase and plasma thiobarbituric acid reactive substances were amplified and the activity/levels of heart glutathione -S- transferase, vitamin C, and vitamin E were lessened by isoproterenol. A down-regulated expression of liver sterol regulatory element-binding protein-2 and liver low-density lipoprotein-receptor genes was observed by a reverse transcription-polymerase chain reaction study. Moreover, histopathology of Sudan III staining revealed an accumulation of fats in the heart of isoproterenol-induced rats. Nevertheless, β-caryophyllene pre-and co-treatment blocked alterations in all the parameters examined in isoproterenol-induced rats and inhibited the risk of MI. Moreover, the in vitro study revealed the potent free radical scavenging and antioxidant effects of β-caryophyllene. β-Caryophyllene's antioxidant and anti-hyperlipidemic properties are the possible mechanisms for the observed protective effects in this investigation.

L-Carnitine improves mechanical responses of cardiomyocytes and restores Ca2+ homeostasis during aging

L-Carnitine (β-hydroxy-γ-trimethylaminobutyric acid, LC) is a crucial molecule for the mitochondrial oxidation of fatty acids. It facilitates the transport of long-chain fatty acids into the mitochondrial matrix. The reduction in LC levels during the aging process has been linked to numerous cardiovascular disorders, including contractility dysfunction, and disrupted intracellular Ca2+ homeostasis. The aim of this study was to examine the effects of long-term (7 months) LC administration on cardiomyocyte contraction and intracellular Ca2+ transients ([Ca2+]i) in aging rats. Male albino Wistar rats were randomly assigned to either the control or LC-treated groups. LC (50 mg/kg body weight/day) was dissolved in distilled water and orally administered for a period of 7 months. The control group received distilled water alone. Subsequently, ventricular single cardiomyocytes were isolated, and the contractility and Ca2+ transients were recorded in aging (18 months) rats. This study demonstrates, for the first time, a novel inotropic effect of long-term LC treatment on rat ventricular cardiomyocyte contraction. LC increased cardiomyocyte cell shortening and resting sarcomere length. Furthermore, LC supplementation led to a reduction in resting [Ca2+]i level and an increase in the amplitude of [Ca2+]i transients, indicative of enhanced contraction. Consistent with these results, decay time of Ca2+ transients also decreased significantly in the LC-treated group. The long-term administration of LC may help restore the Ca2+ homeostasis altered during aging and could be used as a cardioprotective medication in cases where myocyte contractility is diminished.

Clinical Significance of Carnitine in the Treatment of Cancer: From Traffic to the Regulation

Metabolic reprogramming is a common hallmark of cancer cells. Cancer cells exhibit metabolic flexibility to maintain high proliferation and survival rates. In other words, adaptation of cellular demand is essential for tumorigenesis, since a diverse supply of nutrients is required to accommodate tumor growth and progression. Diversity of carbon substrates fueling cancer cells indicate metabolic heterogeneity, even in tumors sharing the same clinical diagnosis. In addition to the alteration of glucose and amino acid metabolism in cancer cells, there is evidence that cancer cells can alter lipid metabolism. Some tumors rely on fatty acid oxidation (FAO) as the primary energy source; hence, cancer cells overexpress the enzymes involved in FAO. Carnitine is an essential cofactor in the lipid metabolic pathways. It is crucial in facilitating the transport of long-chain fatty acids into the mitochondria for β-oxidation. This role and others played by carnitine, especially its antioxidant function in cellular processes, emphasize the fine regulation of carnitine traffic within tissues and subcellular compartments. The biological activity of carnitine is orchestrated by specific membrane transporters that mediate the transfer of carnitine and its derivatives across the cell membrane. The concerted function of carnitine transporters creates a collaborative network that is relevant to metabolic reprogramming in cancer cells. Here, the molecular mechanisms relevant to the role and expression of carnitine transporters are discussed, providing insights into cancer treatment.

Protective effects of β-caryophyllene on mitochondrial damage and cardiac hypertrophy pathways in isoproterenol-induced myocardial infarcted rats

The cardiac mitochondrial damage and cardiac hypertrophy pathways are intimately associated with the pathology of myocardial infarction (MI). The protective effects of β-caryophyllene on mitochondrial damage and cardiac hypertrophy pathways in isoproterenol-induced myocardial infarcted rats were investigated. Isoproterenol (100 mg/kg body weight) was administered to induce MI. The ST-segment, QT interval, and T wave were widened, and the QRS complex and P wave were shortened in the electrocardiogram (ECG) and the serum cardiac diagnostic markers and heart mitochondrial lipid peroxidation products, calcium ions, and reactive oxygen species (ROS) were elevated and the heart mitochondrial antioxidants, tricarboxylic acid cycle, and respiratory chain enzymes were lessened in isoproterenol-induced myocardial infarcted rats. The heart mitochondrial damage was noted in the transmission electron microscopic study. The whole heart weight was increased and the subunits of nicotinamide adenine dinucleotide phosphate - oxidase 2 (Nox 2) genes such as cybb and p22-phox and cardiac hypertrophy genes such as atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), β -myosin heavy chain (β-MHC), and actin alpha skeletal muscle-1(ACTA-1) were highly expressed in the rat's heart by reverse transcription-polymerase chain reaction study. The β-caryophyllene (20 mg/kg body weight) pre- and co-treatment orally, daily for 21 days reversed changes in ECG and lessened cardiac diagnostic markers, ROS, and whole heart weight and ameliorated mitochondrial damage and Nox/ANP/BNP/β-MHC/ACTA-1cardiac hypertrophy pathways in isoproterenol-induced myocardial infarcted rats. The observed effects might be due to the antioxidant, anti-mitochondrial damaging, and anti-cardiac hypertrophic mechanisms of β-caryophyllene.

Post-myocardial infarction fibrosis: Pathophysiology, examination, and intervention

Cardiac fibrosis plays an indispensable role in cardiac tissue homeostasis and repair after myocardial infarction (MI). The cardiac fibroblast-to-myofibroblast differentiation and extracellular matrix collagen deposition are the hallmarks of cardiac fibrosis, which are modulated by multiple signaling pathways and various types of cells in time-dependent manners. Our understanding of the development of cardiac fibrosis after MI has evolved in basic and clinical researches, and the regulation of fibrotic remodeling may facilitate novel diagnostic and therapeutic strategies, and finally improve outcomes. Here, we aim to elaborate pathophysiology, examination and intervention of cardiac fibrosis after MI.

A Carnitine-Containing Product Improves Aspects of Post-Exercise Recovery in Adult Horses

Strenuous exercise can cause tissue damage, leading to an extended recovery period. To counteract delayed post-exercise recovery, a commercial product containing L-carnitine (AID) was tested in adult horses performing consecutive exercise tests to exhaustion. Fit Thoroughbreds were administered an oral bolus of placebo (CON) or AID prior to performing an exercise test to exhaustion (D1). The heart rate (HR) and fetlock kinematics were captured throughout the exercise test. Blood was collected before, 10 min and 1, 4 and 6 h relative to exercise for the quantification of cytokine (IL1β, IL8, IL10, TNFa) gene expression and lactate concentration. Horses performed a second exercise test 48 h later (D2), with all biochemical and physiological measures repeated. The results demonstrate that the horses receiving AID retained a greater (p < 0.05) amount of flexion in the front fetlock on D2 than the horses given CON. The horses presented a reduced (p < 0.05) rate of HR decline on D2 compared to that on D1. The expression of IL1β, IL8 and IL10 increased at 1 h post-exercise on D1 and returned to baseline by 6 h; the cytokine expression pattern was not duplicated on D2. These results provide evidence of disrupted cytokine expression, HR recovery and joint mobility in response to consecutive bouts of exhaustive exercise. Importantly, AID may accelerate recovery through an undetermined mechanism.

Levocarnitine regulates the growth of angiotensin II-induced myocardial fibrosis cells via TIMP-1

This study aimed to explore the effects of tissue inhibitor of metalloproteinases-1 (TIMP-1) on levocarnitine (LC)-mediated regulation of angiotensin II (AngII)-induced myocardial fibrosis (MF) and its underlying mechanisms. H9C2 cells were treated with AngII for 24 h to induce fibrosis. The cells were then treated with LC or transfected with TIMP-1-OE plasmid/si‑TIMP-1. Cell apoptosis, viability, migration, and related gene expression were analyzed. AngII treatment significantly upregulated Axl, α-SMA, and MMP3 expression (P < 0.05) and downregulated STAT4 and TIMP1 expression (P < 0.05) relative to the control levels. After transfection, cells with TIMP-1 overexpression/knockdown were successfully established. Compared with that of the control, AngII significantly inhibited cell viability and cell migration while promoting cell apoptosis (P < 0.05). LC and TIMP-1-OE transfection further suppressed cell viability and migration induced by Ang II and upregulated apoptosis, whereas si-TIMP-1 had the opposite effect. Furthermore, LC and TIMP-1-OE transfection downregulated Axl, AT1R, α-SMA, collagen III, Bcl-2, and MMP3 expression caused by AngII and upregulated caspase 3, p53, and STAT4 expression, whereas si-TIMP-1 had the opposite effect. TIMP-1 is therefore a potential therapeutic target for delaying MF progression.

A coffee enriched with guarana, selenium, and l-carnitine (GSC) has nutrigenomic effects on oxi-inflammatory markers of relapsing-remitting multiple sclerosis patients: A pilot study

Relapsing-remitting multiple sclerosis (RRMS) is the most common clinical course of multiple sclerosis (MS), characterized by a chronic inflammatory state and elevated levels of oxidative markers. Food supplements with potential anti-inflammatory, antioxidant and neuroprotective effects have been tested as possible adjuvants in the treatment of MS. In this sense, this pilot study was carried out with the aim of verifying whether a minimum daily dose of a guarana, selenium and l-carnitine (GSC) based multi supplement, mixed in cappuccino-type coffee, administered for 12 weeks to 28 patients with RRMS could differentially modulate oxidative blood markers (lipoperoxidation, protein carbonylation and DNA oxidation) and inflammatory blood markers (protein levels of cytokines IL-1β, IL-6, TNF-α, IFN-γ, IL-10, gene expression of these cytokines, and NLRP3 and CASP-1 molecules, and C-reactive protein levels). The results indicate that a low concentration of GSC is capable of decreasing the plasma levels of oxidized DNA and pro-inflammatory cytokines of RRMS patients. The results support further research into the action of GSC on clinical symptoms, not only in patients with MS, but also with other neurological conditions.

Biomedical role of L-carnitine in several organ systems, cellular tissues, and COVID-19

Carnitine is a conditionally necessary vitamin that aids in energy creation and fatty acid metabolism. Its bioavailability is higher in vegetarians than in meat-eaters. Deficits in carnitine transporters occur because of genetic mutations or in conjunction with other illnesses. Carnitine shortage can arise in health issues and diseases-including hypoglycaemia, heart disease, starvation, cirrhosis, and ageing-because of abnormalities in carnitine control. The physiologically active form of L-carnitine supports immunological function in diabetic patients. Carnitine has been demonstrated to be effective in the treatment of Alzheimer's disease, several painful neuropathies, and other conditions. It has been used as a dietary supplement for the treatment of heart disease, and it also aids in the treatment of obesity and reduces blood glucose levels. Therefore, L-carnitine shows the potential to eliminate the influences of fatigue in COVID-19, and its consumption is recommended in future clinical trials to estimate its efficacy and safety. This review focused on carnitine and its effect on tissues, covering the biosynthesis, metabolism, bioavailability, biological actions, and its effects on various body systems and COVID-19.

Potential Effects of Bisphenol A on the Heart and Coronary Artery of Adult Male Rats and the Possible Role of L-Carnitine

Bisphenol A (BPA) is an environmental toxin utilized for the production of polycarbonate plastics and epoxy resins. Due to BPA's extensive production and environmental contamination, human exposure is unavoidable. The effects of low-dose of BPA on various body tissues and organs remain controversial. Our study investigated the potential of BPA to induce biochemical, histopathological, and immunohistochemical changes in the coronary artery and myocardium and the potential protective role of L-carnitine (LC). 24 adult Wistar albino male rats were divided equally into a control group, a BPA-treated group (40 mg/kg/d, by gavage for 4 weeks), and a BPA plus LC-treated group (received 40 mg/kg/d of BPA and 300 mg/kg/d of LC, by gavage for 4 weeks). BPA-exposed rats demonstrated structural anomalies in the coronary artery tissue including vacuolation of cells in the media and detachment of the endothelium of the intima. Congestion of blood vessels and infiltration by polynuclear cells were observed in the myocardium. There was an enhanced collagen deposition in both tissues indicating fibrosis. Immunohistochemical changes included enhanced eNOS and caspase-3 expression in the coronary artery and myocardium indicating vascular disease and apoptosis, respectively. Oxidative damage was evident in the coronary artery and the myocardium of BPA-treated rats, which was indicated by the reduced level of glutathione (GSH) and elevated malondydehyde (MDA) levels. The coadministration of LC significantly improved BPA-induced structural alterations and oxidative stress. In conclusion, BPA could potentially cause pathologic changes and oxidative damage in the coronary artery and myocardium, which could be improved by LC coadministration.

The underlying pathological mechanism of ferroptosis in the development of cardiovascular disease

Cardiovascular diseases (CVDs) have been attracting the attention of academic society for decades. Numerous researchers contributed to figuring out the core mechanisms underlying CVDs. Among those, pathological decompensated cellular loss posed by cell death in different kinds, namely necrosis, apoptosis and necroptosis, was widely regarded to accelerate the pathological development of most heart diseases and deteriorate cardiac function. Recently, apart from programmed cell death revealed previously, ferroptosis, a brand-new cellular death identified by its ferrous-iron-dependent manner, has been demonstrated to govern the occurrence and development of different cardiovascular disorders in many types of research as well. Therefore, clarifying the regulatory function of ferroptosis is conducive to finding out strategies for cardio-protection in different conditions and improving the prognosis of CVDs. Here, molecular mechanisms concerned are summarized systematically and categorized to depict the regulatory network of ferroptosis and point out potential therapeutic targets for diverse cardiovascular disorders.

Cytokine storm: behind the scenes of the collateral circulation after acute myocardial infarction

At least 17 million people die from acute myocardial infarction (AMI) every year, ranking it first among causes of death of human beings, and its incidence is gradually increasing. Typical characteristics of AMI include acute onset and poor prognosis. At present, there is no satisfactory treatment, but development of coronary collateral circulation (CCC) can be key to improving prognosis. Recent research indicates that the levels of cytokines, including those related to promoting inflammatory responses and angiogenesis, increase after the onset of AMI. In the early phase of AMI, cytokines play a vital role in inducing development of collateral circulation. However, when myocardial infarction is decompensated, cytokine secretion increases greatly, which may induce a cytokine storm and worsen prognosis. Cytokines can regulate the activation of a variety of signal pathways and form a complex network, which may promote or inhibit the establishment of collateral circulation. We searched for published articles in PubMed and Google Scholar, employing the keyword “acute myocardial infarction”, “coronary collateral circulation” and “cytokine storm”, to clarify the relationship between AMI and a cytokine storm, and how a cytokine storm affects the growth of collateral circulation after AMI, so as to explore treatment methods based on cytokine agents or inhibitors used to improve prognosis of AMI.

L-Carnitine Mitigates Trazadone Induced Rat Cardiotoxicity Mediated via Modulation of Autophagy and Oxidative Stress

Trazodone (TRZ) is an antidepressant drug which widely used to treat insomnia, but it has a cardiotoxic effect which considered one of the TRZ limitations. The aim of this study was to investigate the protective role of l-carnitine in rats against TRZ-induced cardiotoxicity, as well as to look into the molecular mechanisms underlying its cardioprotective effects via autophagy-mediated cell death and oxidative stress. Male albino rats were randomized into four experimental groups (n = 8): normal control, TRZ group (TRZ, 20 mg/kg/day), l-carnitine group (LC, 200 mg/kg/day), and Co-treated group (l-carnitine and TRZ). All treatments were administered via oral gavage for 4 weeks. Cardiac enzymes (AST & CK-MB) and serum cardiac troponin T(cTnI) were assessed. Oxidative stress biomarkers in heart tissue (malondialdehyde; MDA, total thiol, and catalase activity) were measured. Autophagy related-genes (ATG-5 and Beclin-1), P62, and TNF-α were quantified. AST and CK-MB and cTnI significantly (p < 0.001) were increased with enhanced autophagy as well as severe histopathological changes which were manifested as scattered chronic inflammatory cells with focal fragmentation of myocardial fibers and loss of nuclei in TRZ-treated group. However, daily administration of l-carnitine (200 mg/kg) for 28 days completely reversed TRZ-induced the increased cardiac enzymes, autophagy, and myocardial inflammatory processes to the normal values. TRZ administration might have the potential to cause cardiotoxic effects that can be treated with l-carnitine administration.

L-Carnitine Alleviates the Myocardial Infarction and Left Ventricular Remodeling through Bax/Bcl-2 Signal Pathway

Purpose

L-carnitine (LC) is considered to have good therapeutic potential for myocardial infarction (MI), but its mechanism has not been clarified. The aim of the study is to elucidate the cardioprotective effects of LC in mice following MI and related mechanisms.

Methods

ICR mice were treated with LC for 2 weeks after induction of MI with ligation of left anterior descending artery. Electrocardiographic (ECG) recording and echocardiography were used to evaluate cardiac function. H&E staining, TTC staining, and Masson staining were performed for morphological analysis and cardiac fibrosis. ELISA and immunofluorescence were utilized to detect biomarkers and inflammatory mediators. The key proteins in the Bax/Bcl-2 signaling pathway were also examined by Western blot.

Results

Both echocardiography and histological measurement showed an improvement in cardiac function and morphology. Biomarkers such as LDH, NT-proBNP, cTnT, and AST, as well as the inflammatory cytokines IL-1β, IL-6, and TNF-α, were decreased in plasma of mice receiving LC treatment after myocardial injury. In addition, the expression of α-SMA as well as the key proteins in the Bax/Bcl-2 signaling pathway in cardiac myocardium were much lower in mice with LC treatment compared to those without after MI.

Conclusions

Our data suggest that LC can effectively ameliorate left ventricular (LV) remodeling after MI, and its beneficial effects on myocardial function and remodeling may be attributable at least in part to anti-inflammatory and inhibition of the Bax/Bcl-2 apoptotic signaling pathway.