Febuxostat attenuates paroxysmal atrial fibrillation-induced regional endothelial dysfunction

Reno-protective effect of fenofibrate and febuxostat against vancomycin-induced acute renal injury in rats: Targeting PPARγ/NF-κB/COX-II and AMPK/Nrf2/HO-1 signaling pathways

BACKGROUND

Vancomycin (VCM) is used clinically to treat serious infections caused by multi-resistant Gram-positive bacteria, although its use is severely constrained by nephrotoxicity. This study investigated the possible nephroprotective effect of febuxostat (FX) and/or fenofibrate (FENO) and their possible underlying mechanisms against VCM-induced nephrotoxicity in a rat model.

METHODS

Male Wistar rats were randomly allocated into five groups; Control, VCM, FX, FENO, and combination groups. Nephrotoxicity was evaluated histopathologically and biochemically. The oxidative stress biomarkers (SOD, MDA, GSH, total nitrite, GPx, MPO), the apoptotic marker, renal Bcl-2 associated X protein (Bax), and inflammatory and kidney injury markers (IL-1β, IL-6, TNF-α, Nrf2, OH-1, kappa-light-chain-enhancer of activated B cells (NF-κB), NADPH oxidase, Kim-1, COX-II, NGAL, Cys-C were also evaluated.

RESULTS

VCM resulted in significant elevation in markers of kidney damage, oxidative stress, apoptosis, and inflammatory markers. Co-administration of VCM with either/or FX and FENO significantly mitigated nephrotoxicity and associated oxidative stress, inflammatory and apoptotic markers. In comparison to either treatment alone, a more notable improvement was observed with the FX and FENO combination regimen.

CONCLUSION

Our findings show that FX, FENO, and their combination regimen have a nephroprotective impact on VCM-induced kidney injury by suppressing oxidative stress, apoptosis, and the inflammatory response. Renal recovery from VCM-induced injury was accomplished by activation of Nrf2/HO-1 signaling and inhibition of NF-κB expression. This study highlights the importance of FX and FENO as effective therapies for reducing nephrotoxicity in VCM-treated patients.

Developing Pharmacological Therapies for Atrial Fibrillation Targeting Mitochondrial Dysfunction and Oxidative Stress: A Scoping Review

Atrial fibrillation (AF) is a cardiac arrhythmia caused by electrophysiological anomalies in the atrial tissue, tissue degradation, structural abnormalities, and comorbidities. A direct relationship exists between AF and altered mitochondrial activity resulting from membrane potential loss, contractile dysfunction, or decreased ATP levels. This review aimed to elucidate the role of mitochondrial oxidative mechanisms in AF pathophysiology, the impact of mitochondrial oxidative stress on AF initiation and perpetuation, and current therapies. This review followed the Preferred Reporting Items for Systematic Reviews and the Meta-Analysis Extension for Scoping Reviews. PubMed, Excerpta Medica Database, and Scopus were explored until June 2023 using "MESH terms". Bibliographic references to relevant papers were also included. Oxidative stress is an imbalance that causes cellular damage from excessive oxidation, resulting in conditions such as AF. An imbalance in reactive oxygen species production and elimination can cause mitochondrial damage, cellular apoptosis, and cardiovascular diseases. Oxidative stress and inflammation are intrinsically linked, and inflammatory pathways are highly correlated with the occurrence of AF. AF is an intricate cardiac condition that requires innovative therapeutic approaches. The involvement of mitochondrial oxidative stress in the pathophysiology of AF introduces novel strategies for clinical treatment.

The Role of Oxidative Stress in Acute Ischemic Stroke-Related Thrombosis

Acute ischemic stroke is a serious life-threatening disease that affects almost 600 million people each year throughout the world with a mortality of more than 10%, while two-thirds of survivors remain disabled. However, the available treatments for ischemic stroke are still limited to thrombolysis and/or mechanical thrombectomy, and there is an urgent need for developing new therapeutic target. Recently, intravascular oxidative stress, derived from endothelial cells, platelets, and leukocytes, has been found to be tightly associated with stroke-related thrombosis. It not only promotes primary thrombus formation by damaging endothelial cells and platelets but also affects thrombus maturation and stability by modifying fibrin components. Thus, oxidative stress is expected to be a novel target for the prevention and treatment of ischemic stroke. In this review, we first discuss the mechanisms by which oxidative stress promotes stroke-related thrombosis, then summarize the oxidative stress biomarkers of stroke-related thrombosis, and finally put forward an antithrombotic therapy targeting oxidative stress in ischemic stroke.

Febuxostat increases ventricular arrhythmogenesis through calcium handling dysregulation in human induced pluripotent stem cell-derived cardiomyocytes

Febuxostat is a xanthine oxidase inhibitor used to reduce the formation of uric acid and prevent gout attacks. Previous studies have suggested that febuxostat was associated with a higher risk of cardiovascular events, including atrial fibrillation, compared with allopurinol, another anti-hyperuricemia drug. Whereas in our clinical practice, we identified two cases of febuxostat-associated ventricular tachycardia events. The proarrhythmogenic effects of febuxostat on human cardiomyocytes and underlined mechanisms remain poorly understood. In this study, we employed real time cell analysis (RTCA) and calcium transient to investigate the effects of febuxostat on the cytotoxicity and electrophysiology properties of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Up to 10 μM febuxostat treatment did not show toxicity to cell viability. However, 48-hour febuxostat exposure generated dose-dependent increased irregular calcium transients and decreased calcium transient amplitude. Furthermore, RNA-seq analysis indicated that the MAPK signaling pathway was enriched in the febuxostat-treated group, especially the protein kinases JNK. Western blotting of three main protein kinases demonstrated that JNK activation is related to febuxostat-induced arrythmia rather than ERK or p38. The dysfunctional calcium dynamics of febuxostat-treated hiPSC-CMs could be ameliorated by SP600125, the inhibitor of JNK. In conclusion, our study demonstrated that febuxostat increases the predisposition to ventricular arrythmia by dysregulating calcium dynamics.

The Relationship between Uric Acid and the Development, Complication, and Prognosis of Atrial Fibrillation: The Views from a Clinical Study

A large number of studies suggest that uric acid (UA) is related to the occurrence, complications, and prognosis of atrial fibrillation (AF). However, the guidelines did not clearly elaborate on this issue. The current research results need to be summarized to analyze the association between UA and AF. This study found that in the current clinical research on the relationship between UA and AF, studies mainly focus on the development or complications of AF. A lot of repetitive work does not deepen awareness of this question. In contrast, studies investigating the effects of UA-lowering therapy on the management of AF are limited. The only reports deny the protective effect of UA-lowering therapy. For now, we suggest that UA is close to the occurrence and progression of AF; therefore, it may have important significance as a clinical marker. The role of UA-lowering therapy in the management of AF is one of the next key issues to be explored. It will be a meaningful topic to focus on the latest research on AF ablation and to conduct a secondary analysis to explore the prognostic impact of UA on the latest treatment methods for AF. Multiomics techniques may allow us to have a deeper understanding of the role of UA in AF management in the future.

Nephroprotective effects of febuxostat and/or mirtazapine against gentamicin-induced nephrotoxicity through modulation of ERK 1/2, NF-κB and MCP1

OBJECTIVES

This study was conducted to evaluate the potential nephroprotective effects of febuxostat, mirtazapine, and their combination against gentamicin-induced nephrotoxicity.

METHODS

Induction of nephrotoxicity was achieved via gentamicin injection (100 mg/kg, I.P., for 7 days). Two different doses of mirtazapine (15-30 mg/kg), febuxostat (5-10 mg/kg), and their combination were administered daily for 14 days prior to gentamicin injection and then concomitantly with gentamicin for additional 7 days. Nephrotoxicity was evaluated histopathologically and biochemically. Renal caspase-3, extracellular signal-regulated protein kinase 1/2 (ERK1/2), nuclear factor-kappa-β (NF-κβ), and monocyte chemoattractant protein (MCP-1) were assayed.

RESULTS

Febuxostat and mirtazapine significantly (p < 0.05) alleviated biochemical and histopathological alterations that were induced by gentamicin and, for the first time, significantly decreased the renal levels of ERK1/2 and MCP-1. Conclusion: Febuxostat and mirtazapine were found to have a synergistic impact in reducing gentamicin-induced nephrotoxicity.

EXPERT OPINION

The utility of nonpurine xanthine oxidase inhibitor, such as febuxostat and mirtazapine are offering a new potential opportunity for the future nephroprotective effects therapy: Febuxostat and mirtazapine are found to have a synergistic impact in reducing gentamicin-induced nephrotoxicity.

Purine versus non-purine xanthine oxidase inhibitors against cyclophosphamide-induced cardiac and bone marrow toxicity in rats

BACKGROUND AND AIM

Cancer is a fatal and serious disease. Cyclophosphamide (CYC) is a commonly used anticancer drug. Cardiotoxicity and myelotoxicity are life-threatening side effects of CYC treatment. We aimed to evaluate the effect of the xanthine oxidase (XO) inhibitors, allopurinol (ALL) and febuxostat (FEB), on CYC-induced cardio- and hematopoietic toxicity in rats.

METHODS

ALL (100 mg/kg/day) or FEB (10 mg/kg/day) were administered orally to rats in the presence and absence of CYC (200 mg/kg kg i.p. single dose) treatment. Serum creatine kinase-MB creatine kinase myocardial band (CK-MB) and lactate dehydrogenase (LDH) activities were estimated. Complete blood counting (CBC), cardiac and bone marrow XO activity, malondialdehyde level, and superoxide dismutase activity were determined. Cardiac and bone marrow histopathological changes were also evaluated.

RESULTS

ALL and FEB significantly decreased CK-MB and LDH induced by CYC. Disturbed levels of XO, oxidative stress parameters, and CBC were also corrected by both XO inhibitors tested, with amelioration of cardiac histopathological changes caused by CYC. Treatment with FEB, but not ALL, prior to CYC challenges normalized bone marrow histopathological changes.

CONCLUSION

These results suggest that both XO inhibitors tested; ALL and FEB can ameliorate CYC-induced cardiotoxicity. However, only FEB can protect against CYC-induced myelotoxicity, whereas ALL, to the contrary, might aggravate it.

Thrombin Induces Angiotensin II-Mediated Senescence in Atrial Endothelial Cells: Impact on Pro-Remodeling Patterns

BACKGROUND

Besides its well-known functions in hemostasis, thrombin plays a role in various non-hemostatic biological and pathophysiologic processes. We examined the potential of thrombin to promote premature atrial endothelial cells (ECs) senescence.

METHODS AND RESULTS

Primary ECs were isolated from porcine atrial tissue. Endothelial senescence was assessed by measuring beta-galactosidase (SA-β-gal) activity using flow cytometry, oxidative stress using the redox-sensitive probe dihydroethidium, protein level by Western blot, and matrix metalloproteinases (MMPs) activity using zymography. Atrial endothelial senescence was induced by thrombin at clinically relevant concentrations. Thrombin induced the up-regulation of p53, a key regulator in cellular senescence and of p21 and p16, two cyclin-dependent kinase inhibitors. Nicotinamide adenine dinucleotide phosphate NADPH oxidase, cyclooxygenases and the mitochondrial respiration complex contributed to oxidative stress and senescence. Enhanced expression levels of vascular cell adhesion molecule (VCAM)-1, tissue factor, transforming growth factor (TGF)-β and MMP-2 and 9 characterized the senescence-associated secretory phenotype of atrial ECs. In addition, the pro-senescence endothelial response to thrombin was associated with an overexpression of both angiotensin converting enzyme and AT1 receptors and was inhibited by perindoprilat and losartan.

CONCLUSIONS

Thrombin promotes premature ageing and senescence of atrial ECs and may pave the way to deleterious remodeling of atrial tissue by a local up-regulation of the angiotensin system and by promoting pro-inflammatory, pro-thrombotic, pro-fibrotic and pro-remodeling responses. Hence, targeting thrombin and/or angiotensin systems may efficiently prevent atrial endothelial senescence.

Effects of febuxostat on atrial remodeling in a rabbit model of atrial fibrillation induced by rapid atrial pacing

Background

Febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase (XO), may be used in the prevention and management of atrial fibrillation (AF). The purpose of this study was to evaluate the effects of febuxostat on atrial remodeling in a rabbit model of AF induced by rapid atrial pacing (RAP) and the mechanisms by which it acts.

Methods

Twenty-four rabbits were randomly divided into four groups: sham-operated group (Group S), RAP group (Group P), RAP with 5 mg/kg per day febuxostat group (Group LFP), and RAP with 10 mg/kg per day febuxostat group (Group HFP). All rabbits except those in Group S were subjected to RAP at 600 beats/min for four weeks. The effects of febuxostat on atrial electrical and structural remodeling, markers of inflammation and oxidative stress, and signaling pathways involved in the left atrium were examined.

Results

Shortened atrial effective refractory period (AERP), increased AF inducibility, decreased mRNA levels of Cav1.2 and Kv4.3, and left atrial enlargement and dysfunction were observed in Group P, and these changes were suppressed in the groups treated with febuxostat. Prominent atrial fibrosis was observed in Group P, as were increased levels of TGF-β1, Collagen I, and α-SMA and decreased levels of Smad7 and eNOS. Treatment with febuxostat attenuated these differences. Changes in inflammatory and oxidative stress markers induced by RAP were consistent with the protective effects of febuxostat.

Conclusions

This study is the first to find that febuxostat can inhibit atrial electrical and structural remodeling of AF by suppressing XO and inhibiting the TGF-β1/Smad signaling pathway.