Practical prevention of cardiac remodeling and atrial fibrillation with full-spectrum antioxidant therapy and ancillary strategies

Effects of the beta-blocker carvedilol on arrhythmia and long-term clinical outcomes in benign prostate hypertrophy patients

Benign prostatic hypertrophy (BPH) is associated with autonomic dysfunction and sympathetic nervous system mediated by the alpha receptor. However, limited data exist regarding the effects of the beta-blocker (BB) carvedilol on arrhythmia and urologic outcomes in BPH patients. Our database of patients diagnosed with BPH from 2015 to 2020 was used to obtain echocardiography and electrocardiogram data. Inclusion criteria were BPH patients taking BBs. International Prostate Symptom Score questionnaire were used to evaluate the urinary symptoms and quality of life. Among 448 patients with BPH (69.2 ± 10.9 years) taking BBs, 219 patients took carvedilol (48.9%) and 229 patients took a non-carvedilol BB (51.1%; bisoprolol, 184 patients, 80% or nebivolol, 45 patients, 20%). Difference in the baseline characteristics was not observed. During the median 36-month follow-up, a lower incidence of arrhythmic events (P = .029), total urologic events (P < .001), and less use of additive alpha-blocker was observed in the carvedilol group (P = .022). In multivariate analysis, less carvedilol use (P = .019), heart failure (P < .001), stroke (P < .001), and cardiomyopathy (P = .046) were independent risk factors for arrhythmic events. In addition, less carvedilol use (P = .009) and older age (P = .005) were independent risk factors for urologic events based on BB type at the median 36-month follow-up. The use of carvedilol was associated with less arrhythmic events in BPH patients with palpitation and decreased the incidence of urologic events in BPH compared with the use of non-carvedilol BBs in long-term follow-up.

The Bioactivities of Phycocyanobilin from Spirulina

Phycocyanobilin (PCB) is a linear open-chain tetrapyrrole chromophore that captures and senses light and a variety of biological activities, such as anti-oxidation, anti-cancer, and anti-inflammatory. In this paper, the biological activities of PCB are reviewed, and the related mechanism of PCB and its latest application in disease treatment are introduced. PCB can resist oxidation by scavenging free radicals, inhibiting the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and delaying the activity of antioxidant enzymes. In addition, PCB can also be used as an excellent anti-inflammatory agent to reduce the proinflammatory factors IL-6 and IFN-γ and to up-regulate the production of anti-inflammatory cytokine IL-10 by inhibiting the inflammatory signal pathways NF-κB and mitogen-activated protein kinase (MAPK). Due to the above biological activities of phycocyanobilin PCB, it is expected to become a new effective drug for treating various diseases, such as COVID-19 complications, atherosclerosis, multiple sclerosis (MS), and ischaemic stroke (IS).

Effects on the Cell Barrier Function of L-Met and DL-HMTBA Is Related to Metabolic Characteristics and m6A Modification

Methionine is a substrate for protein synthesis and participates in many other biological events via its metabolism. We have previously demonstrated significant differences in the metabolism of L-methionine (L-Met) and its precursor DL-2-hydroxy-4-methylthiobutyric acid (DL-HMTBA) in IPEC-J2 cells. When DL–HMTBA is added to the diet, intracellular methionine (Met) sources also contain the natural form of L-Met. Then, what is the effect on Met metabolism when these two Met sources exist simultaneously? Moreover, the effects of metabolic differences on cell function remain unclear. In this study, it was found that when the proportion of L-Met to DL–HMTBA was ≤ 40%:60%, Met transmethylation was promoted and when the proportion of L-Met to DL-HMTBA was ≤ 85%:15%, Met trans-sulfuration and regeneration were improved. In addition, DL-HMTBA improved the cell barrier function when the ratio of L-Met to DL-HMTBA was ≤ 40%:60%. This finding may be due to the decrease in the proportion of S-adenosylmethionine to S-adenosylhomocysteine and mRNA N⁶-methyladenosine (m⁶A) levels, which increase the mRNA stability and protein expression of tight junction zona occludens-1. To sum up, the effects of L-Met and DL–HMTBA on Met metabolism, especially transmethylation, suggest that DL–HMTBA has the potential to influence the intestinal barrier function of animals through epigenetic processes.

Taurine and Its Derivatives: Analysis of the Inhibitory Effect on Platelet Function and Their Antithrombotic Potential

Taurine is a semi-essential, the most abundant free amino acid in the human body, with a six times higher concentration in platelets than any other amino acid. It is highly beneficial for the organism, has many therapeutic actions, and is currently approved for heart failure treatment in Japan. Taurine has been repeatedly reported to elicit an inhibitory action on platelet activation and aggregation, sustained by in vivo, ex vivo, and in vitro animal and human studies. Taurine showed effectiveness in several pathologies involving thrombotic diathesis, such as diabetes, traumatic brain injury, acute ischemic stroke, and others. As human prospective studies on thrombosis outcome are very difficult to carry out, there is an obvious need to validate existing findings, and bring new compelling data about the mechanisms underlying taurine and derivatives antiplatelet action and their antithrombotic potential. Chloramine derivatives of taurine proved a higher stability and pronounced selectivity for platelet receptors, raising the assumption that they could represent future potential antithrombotic agents. Considering that taurine and its analogues display permissible side effects, along with the need of finding new, alternative antithrombotic drugs with minimal side effects and long-term action, the potential clinical relevance of this fascinating nutrient and its derivatives requires further consideration.

Enhanced cardiomyocyte reactive oxygen species signaling promotes ibrutinib-induced atrial fibrillation

Atrial fibrillation (AF) occurs in up to 11% of cancer patients treated with ibrutinib. The pathophysiology of ibrutinib promoted AF is complicated, as there are multiple interactions involved; the detailed molecular mechanisms underlying this are still unclear. Here, we aimed to determine the electrophysiological and molecular mechanisms of burst-pacing-induced AF in ibrutinib-treated mice. The results indicated differentially expressed proteins in ibrutinib-treated mice, identified through proteomic analysis, were found to play a role in oxidative stress-related pathways. Finally, treatment with an inhibitor of NADPH oxidase (NOX) prevented and reversed AF development in ibrutinib-treated mice. It was showed that the related protein expression of reactive oxygen species (ROS) in the ibrutinib group was significantly increased, including NOX2, NOX4, p22-phox, XO and TGF-β protein expression. It was interesting that ibrutinib group also significantly increased the expression of ox-CaMKII, p-CaMKII (Thr-286) and p-RyR2 (Ser2814), causing enhanced abnormal sarcoplasmic reticulum (SR) Ca²⁺ release and mitochondrial structures, as well as atrial fibrosis and atrial hypertrophy in ibrutinib-treated mice, and apocynin reduced the expression of these proteins. Ibrutinib-treated mice were also more likely to develop AF, and AF occurred over longer periods. In conclusion, our study has established a pathophysiological role for ROS signaling in atrial cardiomyocytes, and it may be that ox-CaMKII and p-CaMKII (Thr-286) are activated by ROS to increase AF susceptibility following ibrutinib treatment. We have also identified the inhibition of NOX as a potential novel AF therapy approach.

Effects of Different Methionine Sources on Methionine Metabolism in the IPEC-J2 Cells

As one of the essential amino acids, methionine (Met) plays an important role in biological events such as methylation and antioxidant properties besides its function in protein synthesis. Different Met sources have been used in animal production, but their effects on Met metabolic pathways are not well understood. In the present study, we investigated the effects of different Met sources (L-Met, DL-Met, DL-2-hydroxy-4-(methylthio)butanoic acid (DL-HMTBA), and DL-methionyl-DL-methionine (DL-MM)) on the metabolism of Met in small intestinal porcine epithelial cell line (IPEC-J2) and the contents of extracellular Met sources. The results showed that concentrations of intracellular Met, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and the ratio of SAM to SAH in the DL-HMTBA group were significantly lower than that in other Met source groups, while the content of 5-methyltetrahydrofolate (5-MTHF) was significantly higher. Moreover, the mRNA levels of MAT2A, AHcy, CBS, MTHFR, and MTR in the DL-HMTBA group were significantly higher than those in other Met source groups. Further study showed that the total content of extracellular Met sources was highest in the DL-HMTBA group, followed by DL-MM group, followed by L-Met and DL-Met groups. These results demonstrated that DL-HMTBA mainly affects the transmethylation and remethylation of Met and it can promote the trans-sulfur metabolism of Met when compared with other Met sources. In addition, most DL-HMTBA and a small amount of DL-MM can escape the intestinal first-pass metabolism and then provide more extracellular Met sources than L-Met and DL-Met. Therefore, this study can provide a theoretical basis for the selection of Met sources in livestock.

Cardiac Resynchronisation Therapy and Cellular Bioenergetics: Effects Beyond Chamber Mechanics

Cardiac resynchronisation therapy is a cornerstone in the treatment of advanced dyssynchronous heart failure. However, despite its widespread clinical application, precise mechanisms through which it exerts its beneficial effects remain elusive. Several studies have pointed to a metabolic component suggesting that, both in concert with alterations in chamber mechanics and independently of them, resynchronisation reverses detrimental changes to cellular metabolism, increasing energy efficiency and metabolic reserve. These actions could partially account for the existence of responders that improve functionally but not echocardiographically. This article will attempt to summarise key components of cardiomyocyte metabolism in health and heart failure, with a focus on the dyssynchronous variant. Both chamber mechanics-related and -unrelated pathways of resynchronisation effects on bioenergetics – stemming from the ultramicroscopic level – and a possible common underlying mechanism relating mechanosensing to metabolism through the cytoskeleton will be presented. Improved insights regarding the cellular and molecular effects of resynchronisation on bioenergetics will promote our understanding of non-response, optimal device programming and lead to better patient care.

Taurine Reverses Atrial Structural Remodeling in Ach-Cacl2 Induced Atrial Fibrillation Rats

Taurine has been reported to have anti-arrhythmia effects, but the anti-atrial fibrillation (AF) effects and its mechanism remain incompletely understood. In the present study, the therapy effects and partly mechanisms were investigated. AF animal model was established by intravenous administered with the mixture of acetylcholine (Ach) and CaCl2 (66 μg/mL + 10 mg/mL) (i.v.) for 7 days. The actions of taurine (99 mg/kg∙d, introgastric administration) on the levels of Hs-CRP, IL-6, TNF-α, MMP-9, AngII, the extent of the fibrosis and ultrastructural changes in left atrial were studied. The data showed that the serum levels of TNF-α, IL-6, AngII and the plasma levels of Hs-CRP and MMP-9 were significantly elevated in automatic recovery group relative to the control group (p < 0.01), which were all decreased by taurine administration (p < 0.01) similar to Verapamil treatment. Masson's trichrome staining of the left atrial tissue showed an obvious interstitial fibrosis in rats of automatic recovery group. The alteration could be reversed by additional taurine. Electron microscopy revealed that taurine administration could significantly alleviate the ultrastructural damage of atrial cells, and the effects were similar to the Verapamil treatment. In conclusion, the results suggested that taurine could inhibit the structural remodeling of AF in rats partly by decreasing the levels of inflammatory factors and profibrotic molecules, attenuating the extent of myocardial fibrosis and protecting the integrity of myocardial ultrastructure.

[Changes of two-pore K+ channel TASK-1 in diabetic myocardial injury in rats]

OBJECTIVE

To investigate the changes of the two- pore K⁺ channel TASK-1 in diabetic rats with myocardial injury.

METHODS

Thirty-six SD rats were divided into normal group (N), diabetes at 4 weeks (DM 4W) group, and diabetes at 8 weeks (DM 8W) group. The cardiac functions of the rats were determined using cardiac ultrasonography, and the body weight and heart weight of the rats at different time points were measured to calculate the heart/body weight ratio (HW/BW). Myocardial fibrosis in the rats was assessed using Masson's staining. The protein expression of TASK-1 in the myocardium was detected using Western blotting. Whole- cell patch clamp technique was used to record the action potential duration (APD) and twopore domain potassium channel TASK- 1 current in acutely isolated rat ventricular myocytes. meanwhile, The inhibition of TASK-1 current was observed by the TASK-1 specific inhibitor ML-365.

RESULTS

Compared with the normal group, the diabetic rats showed significantly increased HW/BW (P &lt; 0.05), end- diastole left ventricular diameter (LVIDd), end- systolic left ventricular diameter (LVIDs), and TASK-1 protein expression, with obviously decreased left ventricular diameter shortening rate (FS) and ejection fraction (EF) (P &lt; 0.01). Masson staining showed that in diabetic rats, the collagen fibers were thickened, interwoven into a network with uneven arrangement and increased deposition. Compared with DM 4W group, the rats in DM 8W group exhibited progressive increases in LVIDd, LVIDs, HW/BW, and TASK-1 expression (P &lt; 0.01 or 0.05); FS and EF were further decreased (P &lt; 0.01). Masson staining showed worsened morphological changes of the myocardium with increased deposition. Compared with that in the normal group, the current of TASK- 1 in diabetic rats at 8 weeks was significantly reduced (P &lt; 0.01) and the duration of action potential was extended (P &lt; 0.05). The TASK-1 current was successfully inhibited by ML-365.

CONCLUSIONS

Diabetes can induce myocardial fibrosis and aggravate myocardial injury possibly in relation to changes in the protein expression and current of the two-port potassium channel TASK-1.

Edible Cyanobacterial Genus Arthrospira: Actual State of the Art in Cultivation Methods, Genetics, and Application in Medicine

The cyanobacterial genus Arthrospira appears very conserved and has been divided into five main genetic clusters on the basis of molecular taxonomy markers. Genetic studies of seven Arthrospira strains, including genome sequencing, have enabled a better understanding of those photosynthetic prokaryotes. Even though genetic manipulations have not yet been performed with success, many genomic and proteomic features such as stress adaptation, nitrogen fixation, or biofuel production have been characterized. Many of above-mentioned studies aimed to optimize the cultivation conditions. Factors like the light intensity and quality, the nitrogen source, or different modes of growth (auto-, hetero-, or mixotrophic) have been studied in detail. The scaling-up of the biomass production using photobioreactors, either closed or open, was also investigated to increase the production of useful compounds. The richness of nutrients contained in the genus Arthrospira can be used for promising applications in the biomedical domain. Ingredients such as the calcium spirulan, immulina, C-phycocyanin, and γ-linolenic acid (GLA) show a strong biological activity. Recently, its use in the fight against cancer cells was documented in many publications. The health-promoting action of "Spirulina" has been demonstrated in the case of cardiovascular diseases and age-related conditions. Some compounds also have potent immunomodulatory properties, promoting the growth of beneficial gut microflora, acting as antimicrobial and antiviral. Products derived from Arthrospira were shown to successfully replace biomaterial scaffolds in regenerative medicine. Supplementation with the cyanobacterium also improves the health of livestock and quality of the products of animal origin. They were also used in cosmetic preparations.

Pharmacokinetics of aconitine-type alkaloids after oral administration of Fuzi (Aconiti Lateralis Radix Praeparata) in rats with chronic heart failure by microdialysis and ultra-high performance liquid chromatography-tandem mass spectrometry

ETHNOPHARMACOLOGICAL RELEVANCE

Fuzi [the lateral root of Aconitum carmichaeli Debx (Ranunculaceae)] is a well-known traditional medicinal herb used to treat chronic heart failure (CHF). Aconitine-type alkaloids are major alkaloids that are responsible for the pharmacological activity and toxicity of this herb.To investigate therapeutic effects and pharmacokinetic profiles of aconitine-type alkaloids in CHF rats.

MATERIALS AND METHODS

The plasma pharmacokinetic profiles of aconitine, mesaconitine, and hypaconitine were investigated after once treatment of Fuzi extract (containing aconitine 0.086 mg/g, mesaconitine 0.84 mg/g, and hypaconitine 1.97 mg/g) using a rapid and sensitive combinative method of ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and microdialysis (MD). The cardiac function and antioxidant enzyme activities were also evaluated.

RESULTS

Recoveries of MD sampling ranged from 35.06% to 45.74% with RSD below 6.05%. Fuzi extract improved the myocardial function and antioxidant enzymatic activities of rats with CHF. Aconitine, mesaconitine, and hypaconitine exhibited slower absorption into the bloodstream, and yielded 11-fold less values of area under concentration-time curve (AUC) in the CHF rats than those in normal rats. The plasma AUC showed that the maximum blood concentration (Cmax) was 5.561 ng/mL for aconitine, 17.30 ng/mL for mesaconitine, and 17.78 ng/mL for hypaconitine in normal rats, while these were 0.6059 ng/mL, 2.430, and 0.7461 ng/mL in CHF rats, respectively.

CONCLUSION

Aconitine-type alkaloids associated with Fuzi׳s efficacy have lower intake and slower elimination in the CHF rats, indicating a non-interdependent relationship between its efficacy and toxicity. It may contribute to the depth understanding of the toxicological and pharmacological profiles of Fuzi and further benefit the herbal drug development with safety and efficacy for CHF treatment.

Effect of rosuvastatin on atrial structural remodeling in rabbits with myocardial infarction

The present study aimed to investigate the effect of rosuvastatin on atrial structural remodeling in rabbits with myocardial infarction (MI). The rabbits were randomly divided into 4 groups: The sham operation group (S; n=8), the MI group (MI; n=7), the group with low-dose rosuvastatin [R_s; 2.5 mg/(kg/d), n=7] and the group with high-dose rosuvastatin [R_l, 5 mg/(kg/d), n=8]. A rabbit MI model was established via ligation of the anterior descending coronary artery. After 8 weeks of intervention, the left atrial diameter (LAD), atrial collagen content, expression level of type I collagen and left ventricular ejection fraction (LVEF) were measured. LAD in the MI group was significantly larger than the S, R_s and R_l groups after 8 weeks. The left atrial collagen content of the MI group was also significantly greater than those observed in the other 3 groups. The expression of type I collagen in the MI group was significantly increased compared to the other 3 groups. However, LVEF of the MI group was lower compared to the other 3 groups. There were no significant differences between the R_s and R_l groups in the above indexes. In conclusion, rosuvastatin can improve post-MI atrial structural remodeling.

Proton pump inhibitors as also inhibitors of atrial fibrillation

Proton pump inhibitors (PPIs) are widely used for the treatment of acid-related upper digestive diseases, including gastric and duodenal ulcer and gastroesophageal reflux disease (GERD). Remarkably, several small clinical trials have shown that these drugs also reduce the symptoms and frequency of atrial fibrillation (AF) episodes in patients treated for comorbid acid reflux. Although the mechanism remains unclear, the effect might pinpoint a connection between GERD and AF. To this end, it is known that both oxidants and inflammation affect initiation and maintenance of AF, and PPIs may reduce symptoms and frequency of AF episodes through their antioxidant and anti-inflammatory effects. This review focuses on the anti-AF effects of PPIs beyond their inhibition of gastric acid production.

Resveratrol alleviates endotoxin-induced myocardial toxicity via the Nrf2 transcription factor

Background/Aims

Septic cardiomyopathy is a severe condition that remains a challenge for clinical management. This study investigated whether the natural polyphenolic compound resveratrol could be used as a prophylactic treatment to alleviate sepsis-related myocardial injury; the underlying molecular mechanisms were deciphered by both in vitro and in vivo experiments.

Methods

A mouse model of endotoxin-induced cardiomyopathy was developed by intraperitoneal injection of LPS, and resveratrol was administered prophylatically to the animals. Serum LDH and CK activities were measured to detect myocardial injury, and echocardiography was performed to monitor cardiac structure and function. Various cytokines/chemokines and the Nrf2 antioxidant defense system were examined in the heart tissue. The effects of resveratrol on LPS-induced Nrf2 activation, ROS generation, and apoptotic cell death were further investigated in cultured primary human cardiomyocytes. An Nrf2 specific siRNA was used to define its role in resveratrol-mediated cardiomyocyte protective effect.

Results

Resveratrol pretreatment significantly attenuated LPS-induced myocardial injury in mice, which was associated with suppressed proinflammatory cytokine production and enhanced Nrf2 activation in the heart. In cultured primary human cardiomyocytes, resveratrol activated Nrf2, inhibited LPS-induced ROS generation, and effectively protected the cells from LPS-induced apoptotic cell death. Knockdown of Nrf2 abrogated resveratrol-mediated protection of the cells from LPS-induced cell death.

Conclusion

Resveratrol effectively alleviates endotoxin-induced cardiac toxicity through mechanisms that involve the Nrf2 antioxidant defense pathway. Our data suggest that resveratrol might be developed as a useful prophylactic management for septic cardiomyopathy.

Oxidative stress in atrial fibrillation: an emerging role of NADPH oxidase

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Patients with AF have up to seven-fold higher risk of suffering from ischemic stroke. Better understanding of etiologies of AF and its thromboembolic complications are required for improved patient care, as current anti-arrhythmic therapies have limited efficacy and off target effects. Accumulating evidence has implicated a potential role of oxidative stress in the pathogenesis of AF. Excessive production of reactive oxygen species (ROS) is likely involved in the structural and electrical remodeling of the heart, contributing to fibrosis and thrombosis. In particular, NADPH oxidase (NOX) has emerged as a potential enzymatic source for ROS production in AF based on growing evidence from clinical and animal studies. Indeed, NOX can be activated by known upstream triggers of AF such as angiotensin II and atrial stretch. In addition, treatments such as statins, antioxidants, ACEI or AT1RB have been shown to prevent post-operative AF; among which ACEI/AT1RB and statins can attenuate NOX activity. On the other hand, detailed molecular mechanisms by which specific NOX isoform(s) are involved in the pathogenesis of AF and the extent to which activation of NOX plays a causal role in AF development remains to be determined. The current review discusses causes and consequences of oxidative stress in AF with a special focus on the emerging role of NOX pathways.

Salsalate may have broad utility in the prevention and treatment of vascular disorders and the metabolic syndrome

In the high proportion of vascular disorders associated with excessive oxidative stress and production of pro-inflammatory cytokines, activation of NF-kappaB plays a key pathogenic role. Thus, there is considerable evidence that NF-kappaB is a mediator of atherogenesis, plaque destabilization, ischemia-reperfusion damage, cardiac remodeling, atrial fibrillation, and aneurysm formation and rupture; some studies suggest that it may also play a role in the microvascular complications of diabetes. I kappaB kinase-beta (IKK beta) is the upstream kinase that appears to be primarily responsible for NF-kappaB activation in these disorders; moreover, chronic IKK beta activation plays a prominent role in induction of insulin resistance in the metabolic syndrome. Salicylate inhibits IKK beta in concentrations that are achievable with dose schedules traditionally used in treating rheumatoid arthritis (3-4.5 g daily); indeed, this is likely to be the mechanism responsible for salicylate's utility in this disorder. Salicylate, unlike aspirin, is only a very weak, reversible inhibitor of cyclooxygenase in clinical doses, and thus is not associated with the potentially dangerous side effects seen with NSAIDs; fully reversible ototoxicity, the dose-limiting side effect in salicylate therapy, can be avoided in most patients by dosage adjustment. Hence, it is proposed that salicylate may have practical utility in the prevention or management of a wide range of vascular disorders as well as of metabolic syndrome and diabetes; its efficacy in these regards would likely be complemented by effective antioxidant measures, which would lessen the stimulus to NF-kappaB activation while providing benefits independent of NF-kappaB activity. Salsalate, consisting of two salicylate molecules united by an ester bond, is a venerable drug that may be the best tolerated delivery vehicle for salicylate. Appropriate rodent studies should pave the way for clinical trials with salsalate in patients at vascular risk.