l -Carnitine ameliorates the oxidative stress response to angiotensin II by modulating NADPH oxidase through a reduction in protein kinase c activity and NF-κB translocation to the nucleus

NADPH Oxidases in Cancer Therapy-Induced Cardiotoxicity: Mechanisms and Therapeutic Approaches

Cancer therapy-induced cardiotoxicity remains a significant clinical challenge, limiting the efficacy of cancer treatments and impacting long-term survival and quality of life. NADPH oxidases, a family of enzymes that are able to generate reactive oxygen species (ROS), have emerged as key players in the pathogenesis of cardiotoxicity associated with various cancer therapies. This review comprehensively examines the role of NADPH oxidases in cancer therapy-induced cardiotoxicity, elucidating the underlying mechanisms and exploring potential therapeutic approaches. We discuss the structure and function of NADPH oxidases in the cardiovascular system and their involvement in cardiotoxicity induced by anthracyclines and ionizing radiation. The molecular mechanisms by which NADPH oxidase-derived ROS contribute to cardiac injury are explored, including direct oxidative damage, activation of pro-apoptotic pathways, mitochondrial dysfunction, vascular damage, inflammation, fibrosis, and others. Furthermore, we evaluate therapeutic strategies targeting NADPH oxidases, such as specific inhibitors, antioxidant therapies, natural products, and other cardioprotectors. The review also addresses current challenges in the field, including the need for isoform-specific targeting and the identification of reliable biomarkers. Finally, we highlight future research directions aimed at mitigating NADPH oxidase-mediated cardiotoxicity and alleviating cardiovascular side effects in cancer survivors. By synthesizing current knowledge and identifying knowledge gaps, this review provides a rationale for future studies and the development of novel cardioprotective strategies in cancer therapy.

Gastroprotective Effects of Aqueous Extracts of Broccoli Stems on Acute Injury in Rats: A Comprehensive Evaluation of Gastric Function and Inflammatory Responses

Background and Objectives: Acute gastric injury is a prevalent gastrointestinal disorder characterized by inflammation and damage to the stomach lining. In this study, we investigated the therapeutic potential effects of broccoli stem extract (BSE) against acute gastritis in a rat model. Materials and Methods: The antioxidant properties of BSE were evaluated through DPPH and ABTS radical scavenging activity assays and total polyphenol content analysis. Acute gastric injury was induced using 150 mM HCl/60% EtOH, and male SD rats (6-weeks old, n = 6/group) were administered BSE by oral gavage at concentrations of 50, 125, and 250 mg/kg. Results: The BSE 250 mg/kg group exhibited significant relief of clinical signs compared to the negative control group. In addition, the BSE 250 mg/kg group showed significant improvements in gastric tissue, including macroscopic reductions in ulcer size and improved overall gastric morphology as assessed through gross examination, as well as microscopic improvements such as reduced inflammation and the restoration of mucosal integrity observed in histopathological analysis. BSE modulated NF-κB signaling, decreased inflammatory cytokines (TNF-α, IL-1β, and IL-6), and increased PGE2 levels. Pyloric ligation experiments demonstrated reduced pepsin and gastric acid secretion. Improvements in gastric emptying and gastrointestinal motility were also observed in the BSE-treated group. Conclusions: These findings highlight the potential of BSE as an effective therapeutic agent for acute gastritis in rats, offering significant improvements in gastric damage, inflammation, and motility.

Precision nutrition to reset virus-induced human metabolic reprogramming and dysregulation (HMRD) in long-COVID

SARS-CoV-2, the etiological agent of COVID-19, is devoid of any metabolic capacity; therefore, it is critical for the viral pathogen to hijack host cellular metabolic machinery for its replication and propagation. This single-stranded RNA virus with a 29.9 kb genome encodes 14 open reading frames (ORFs) and initiates a plethora of virus-host protein-protein interactions in the human body. These extensive viral protein interactions with host-specific cellular targets could trigger severe human metabolic reprogramming/dysregulation (HMRD), a rewiring of sugar-, amino acid-, lipid-, and nucleotide-metabolism(s), as well as altered or impaired bioenergetics, immune dysfunction, and redox imbalance in the body. In the infectious process, the viral pathogen hijacks two major human receptors, angiotensin-converting enzyme (ACE)-2 and/or neuropilin (NRP)-1, for initial adhesion to cell surface; then utilizes two major host proteases, TMPRSS2 and/or furin, to gain cellular entry; and finally employs an endosomal enzyme, cathepsin L (CTSL) for fusogenic release of its viral genome. The virus-induced HMRD results in 5 possible infectious outcomes: asymptomatic, mild, moderate, severe to fatal episodes; while the symptomatic acute COVID-19 condition could manifest into 3 clinical phases: (i) hypoxia and hypoxemia (Warburg effect), (ii) hyperferritinemia ('cytokine storm'), and (iii) thrombocytosis (coagulopathy). The mean incubation period for COVID-19 onset was estimated to be 5.1 days, and most cases develop symptoms after 14 days. The mean viral clearance times were 24, 30, and 39 days for acute, severe, and ICU-admitted COVID-19 patients, respectively. However, about 25-70% of virus-free COVID-19 survivors continue to sustain virus-induced HMRD and exhibit a wide range of symptoms that are persistent, exacerbated, or new 'onset' clinical incidents, collectively termed as post-acute sequelae of COVID-19 (PASC) or long COVID. PASC patients experience several debilitating clinical condition(s) with >200 different and overlapping symptoms that may last for weeks to months. Chronic PASC is a cumulative outcome of at least 10 different HMRD-related pathophysiological mechanisms involving both virus-derived virulence factors and a multitude of innate host responses. Based on HMRD and virus-free clinical impairments of different human organs/systems, PASC patients can be categorized into 4 different clusters or sub-phenotypes: sub-phenotype-1 (33.8%) with cardiac and renal manifestations; sub-phenotype-2 (32.8%) with respiratory, sleep and anxiety disorders; sub-phenotype-3 (23.4%) with skeleto-muscular and nervous disorders; and sub-phenotype-4 (10.1%) with digestive and pulmonary dysfunctions. This narrative review elucidates the effects of viral hijack on host cellular machinery during SARS-CoV-2 infection, ensuing detrimental effect(s) of virus-induced HMRD on human metabolism, consequential symptomatic clinical implications, and damage to multiple organ systems; as well as chronic pathophysiological sequelae in virus-free PASC patients. We have also provided a few evidence-based, human randomized controlled trial (RCT)-tested, precision nutrients to reset HMRD for health recovery of PASC patients.

L-Carnitine augments probenecid anti-inflammatory effect in monoiodoacetate-induced knee osteoarthritis in rats: involvement of miRNA-373/P2X7/NLRP3/NF-κB milieu

Osteoarthritis (OA) is a degenerative joint disease, whereas the underlying molecular trails involved in its pathogenesis are not fully elucidated. Hence, the current study aimed to investigate the role of miRNA-373/P2X7/NLRP3/NF-κB trajectory in its pathogenesis as well as the possible anti-inflammatory effects of probenecid and l-carnitine in ameliorating osteoarthritis via modulating this pathway. In the current study, male Sprague Dawley rats were used and monoiodoacetate (MIA)-induced knee osteoarthritis model was adopted. Probenecid and/or L-carnitine treatments for 14 days succeeded in reducing OA knee size and reestablishing motor coordination and joint mobility assessed by rotarod testing. Moreover, different treatments suppressed the elevated serum levels of IL-1β, IL-18, IL-6, and TNF-α via tackling the miRNA-373/P2X7/NLRP3/NF-κB, witnessed as reductions in protein expressions of P2X7, NLRP3, cleaved caspase-1 and NF-κB. These were accompanied by increases in procaspase-1 and IκB protein expression and in miRNA-373 gene expression OA knee to various extents. In addition, different regimens reversed the abnormalities observed in the H and E as well as Safranin O-Fast green OA knees stained sections. Probenecid or l-carnitine solely showed comparable results on the aforementioned parameters, whereas the combination therapy had the most prominent effect on ameliorating the aforementioned parameters. In conclusion, l-carnitine augmented the probenecid's anti-inflammatory effect to attenuate MIA-induced osteoarthritis in rats by provoking the miRNA-373 level and inhibiting the P2X7/NLRP3/NF-κB milieu, leading to the suppression of serum inflammatory cytokines: IL-1β, IL-18, IL-6, and TNF-α. These findings suggest the possibility of using probenecid and l-carnitine as a useful therapeutic option for treatment of osteoarthritis.

L-carnitine reduces acute lung injury via mitochondria modulation and inflammation control in pulmonary macrophages

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is a critical respiratory syndrome with limited effective interventions. Lung macrophages play a critical role in the pathogenesis of abnormal inflammatory response in the syndrome. Recently, impaired fatty acid oxidation (FAO), one of the key lipid metabolic signalings, was found to participate in the onset and development of various lung diseases, including ALI/ARDS. Lipid/fatty acid contents within mouse lungs were quantified using the Oil Red O staining. The protective effect of FAO activator L-carnitine (Lca, 50, 500, or 5 mg/mL) was evaluated by cell counting kit 8 (CCK-8) assay, real-time quantitative PCR (qPCR), ELISA, immunoblotting, fluorescence imaging, and fluorescence plate reader detection in lipopolysaccharide (LPS) (100 ng/mL)-stimulated THP-1-derived macrophages. The in vivo efficacy of Lca (300 mg/kg) was determined in a 10 mg/kg LPS-induced ALI mouse model. We found for the first time that lipid accumulation in pulmonary macrophages was significantly increased in a classical ALI murine model, which indicated disrupted FAO induced by LPS. Lca showed potent anti-inflammatory and antioxidative effects on THP-1 derived macrophages upon LPS stimulation. Mechanistically, Lca was able to maintain FAO, mitochondrial activity, and ameliorate mitochondrial dynamics. In the LPS-induced ALI mouse model, we further discovered that Lca inhibited neutrophilic inflammation and decreased diffuse damage, which might be due to the preservation of mitochondrial homeostasis. These results broadened our understanding of ALI/ARDS pathogenesis and provided a promising drug candidate for this syndrome.

Artemisinin and l-carnitine combination therapy alters the erythrocytes redox status

Hematopoiesis is a sensitive target of artemisinin (ART) and its derivatives, and hemolysis is one of their commonly reported side effects. L-carnitine (LC), an amino acid derivative involved in lipid metabolism, is beneficial for hematological parameters. Sixty adult laboratory mice were randomly divided into six groups. Group I (control) received saline and corn oil; groups II and III received therapeutic (50 mg/kg) and toxic (250 mg/kg) doses of ART, respectively; groups IV and V received 370 mg/kg LC along with the 50 and 250 mg/kg ART, respectively; and group VI received 370 mg/kg LC. Drugs were administered orally for seven consecutive days. The erythrocyte glucose 6-phosphate dehydrogenase (G6PD), catalase (CAT), and peroxidase (POX) activity, and the reduced glutathione (GSH) level were assessed by colorimetric methods. ART reduced the G6PD activity both at therapeutic and toxic doses. The therapeutic dose of ART reduced the CAT activity and the GSH level, non-significantly. The toxic dose of ART reduced the CAT activity and increased the POX activity. LC reduced the G6PD, CAT, and POX activities and increased GSH level. The therapeutic dose of ART and LC showed synergy in reducing the G6PD activity. LC and ART combination reduced POX activity and increased GSH level without any significant effect on the CAT activity. Inhibition of G6PD may be a potentially new mechanism of ART action. Co-administration of LC with ART or following treatment with ART may have protective effects on erythrocytes. This article is protected by copyright. All rights reserved.

Mechanism of Vascular Toxicity in Rats Subjected to Treatment with a Tyrosine Kinase Inhibitor

Sunitinib (Su) is a tyrosine kinase inhibitor with antiangiogenic and antineoplastic effects that is recommended therapy for renal cell carcinoma, gastrointestinal stromal tumors, and pancreatic neuroendocrine tumors. Arterial hypertension is one of the adverse effects observed in the treatment with Su. The aim of this work was to deepen our understanding of the underlying mechanisms involved in the development of this side effect. Studies on endothelial function, vascular remodeling and nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) system were carried out in thoracic aortas from rats treated with Su for three weeks. Animals subjected to Su treatment presented with increased blood pressure and reduced endothelium-dependent vasodilation, the latter being reverted by NADPH oxidase blockade. Furthermore, vascular remodeling and stronger Masson trichrome staining, together with enhanced immunofluorescence signal for collagen 1 alpha 1 (Col1α1), were observed in aortas from treated animals. These results were accompanied by a significant elevation in superoxide anion production and the activity/protein/gene expression of NADPH oxidase isoforms (NOX1, NOX2, and NOX4), which was also prevented by NOX inhibition. Furthermore, a decrease in nitric oxide (NO) levels and endothelial nitric oxide synthase (eNOS) activation was observed in aortas from Su-treated animals. All these results indicate that endothelial dysfunction secondary to changes in vascular remodeling and oxidative stress might be responsible for the typical arterial hypertension that develops following treatment with Su.

Sunitinib-induced oxidative imbalance and retinotoxic effects in rats

AIMS

Sunitinib (Su), a tyrosine kinase inhibitor, is one of the most commonly used anti-angiogenic drugs. Some studies have described retinal detachment and photoreceptor damage following systemic exposure to Su, despite beneficial effects achieved with local treatment of ocular pathologies. The aim of this study was to explore the role of NADPH oxidase system and oxidative stress in eyes from Su-treated animals.

MAIN METHODS

Male Wistar rats were administered 25 mg Su/kg body weight/day incorporated in the chow for 3 weeks. Upon treatment completion, NADPH oxidase activity and ROS levels were measured in ocular tissue by chemiluminescence and dihydroethidium (DHE) staining, respectively. The expression of NADPH oxidase isoforms (NOX1, NOX2 and NOX4), antioxidant enzymes and endothelial/inducible nitric oxidase isoforms (eNOS/iNOS) in the eyecup and/or retina were measured via immunofluorescence, immunoblotting and RT-qPCR.

KEY FINDINGS

NADPH oxidase activity/expression increased in eyecup and retinas from Su-treated rats. Immunohistofluorescence studies in retinal layer confirmed a higher signal of NADPH oxidase isoforms after Su treatment. Treated animals also presented with reductions in NO levels and eNOS expression, whereas iNOS was upregulated. Finally, a significant depletion of antioxidant enzyme glutathione peroxidase was measured in eyecups of rats following Su exposure, and the opposite pattern was seen for glutathione reductase and superoxide dismutase.

SIGNIFICANCE

This study demonstrates that Su treatment is associated with NADPH oxidase-derived oxidative stress in the eye. Long-term treatment of Su should be properly monitored to avoid retinotoxic effects that might result in ocular pathologies and sight-threatening conditions.