Protective effect of angiotensin II receptor blocker against oxidative stress and inflammation in an oral mucositis experimental model

Assessment of Oxidative Stress-Induced Oral Epithelial Toxicity

Reactive oxygen species (ROS) are highly reactive molecules generated in living organisms and an excessive production of ROS culminates in oxidative stress and cellular damage. Notably, oxidative stress plays a critical role in the pathogenesis of a number of oral mucosal diseases, including oral mucositis, which remains one of cancer treatments' most common side effects. We have shown previously that oral keratinocytes are remarkably sensitive to oxidative stress, and this may hinder the development and reproducibility of epithelial cell-based models of oral disease. Here, we examined the oxidative stress signatures that parallel oral toxicity by reproducing the initial events taking place during cancer treatment-induced oral mucositis. We used three oral epithelial cell lines (an immortalized normal human oral keratinocyte cell line, OKF6, and malignant oral keratinocytes, H357 and H400), as well as a mouse model of mucositis. The cells were subjected to increasing oxidative stress by incubation with hydrogen peroxide (H2O2) at concentrations of 100 μM up to 1200 μM, for up to 24 h, and ROS production and real-time kinetics of oxidative stress were investigated using fluorescent dye-based probes. Cell viability was assessed using a trypan blue exclusion assay, a fluorescence-based live-dead assay, and a fluorometric cytotoxicity assay (FCA), while morphological changes were analyzed by means of a phase-contrast inverted microscope. Static and dynamic real-time detection of the redox changes in keratinocytes showed a time-dependent increase of ROS production during oxidative stress-induced epithelial injury. The survival rates of oral epithelial cells were significantly affected after exposure to oxidative stress in a dose- and cell line-dependent manner. Values of TC50 of 800 μM, 800 μM, and 400 μM were reported for H400 cells (54.21 ± 9.04, p < 0.01), H357 cells (53.48 ± 4.01, p < 0.01), and OKF6 cells (48.64 ± 3.09, p < 0.01), respectively. Oxidative stress markers (MPO and MDA) were also significantly increased in oral tissues in our dual mouse model of chemotherapy-induced mucositis. In summary, we characterized and validated an oxidative stress model in human oral keratinocytes and identified optimal experimental conditions for the study of oxidative stress-induced oral epithelial toxicity.

Olmesartan Ameliorates Organ Injury and Mortality in Rats With Peritonitis-Induced Sepsis

INTRODUCTION

Sepsis and related complications lead to high morbidity and mortality in humans and animals. Olmesartan medoxomil (OLM), a nonpeptide angiotensin II type 1 receptor blocker, has antiinflammatory and antioxidative effects in various experimental animal models. The present study aimed to investigate whether OLM protects against sepsis in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP).

METHODS

Sepsis was induced by CLP in anesthetized rats. OLM was administered intraperitoneally 3 h after CLP onset. Hemodynamic, biochemical, and inflammatory parameters were analyzed.

RESULTS

The administration of OLM in CLP rats significantly improved their survival rate. Moreover, OLM mitigated CLP-induced hypotension and organ injury (indicated by biochemical parameters), but not tachycardia. OLM significantly reduced the plasma levels of interleukin-6 and nitric oxide.

CONCLUSIONS

OLM markedly attenuated CLP-induced hypotension and organ injury, and hence improved survival by inhibiting the inflammatory response and nitrosative stress in this clinically relevant model of sepsis.

Sildenafil improves radiation-induced oral mucositis by attenuating oxidative stress, NF-κB, ERK and JNK signalling pathways

Radiation-induced oral mucositis is a common and dose-limiting complication of head and neck radiotherapy with no effective treatment. Previous studies revealed that sildenafil, a phosphodiesterase 5 inhibitor, has anti-inflammatory and anti-cancer effects. In this study, we investigated the effect of sildenafil on radiation-induced mucositis in rats. Two doses of radiation (8 and 26 Gy X-ray) were used to induce low-grade and high-grade oral mucositis, separately. A control group and three groups of sildenafil citrate-treated rats (5, 10, and 40 mg/kg/day) were used for each dose of radiation. Radiation increased MDA and activated NF-κB, ERK and JNK signalling pathways. Sildenafil significantly decreased MDA level, nitric oxide (NO) level, IL1β, IL6 and TNF-α. The most effective dose of sildenafil was 40 mg/kg/day in this study. Sildenafil also significantly inhibited NF-κB, ERK and JNK signalling pathways and increased bcl2/bax ratio. In addition, high-dose radiation severely destructed the mucosal layer in histopathology and led to mucosal cell apoptosis in the TUNEL assay. Sildenafil significantly improved mucosal structure and decreased inflammatory cell infiltration after exposure to high-dose radiation and reduced apoptosis in the TUNEL assay. These findings show that sildenafil can improve radiation-induced oral mucositis and decrease the apoptosis of mucosal cells via attenuation of inflammation and oxidative stress.

Emerging approaches of wound healing in experimental models of high-grade oral mucositis induced by anticancer therapy

Clinical guidelines for oral mucositis (OM) still consist in palliative care. Herein, we summarize cellular and molecular mechanisms of OM ulceration in response to chemical therapies in animal models. We discuss evidenced anti-inflammatory and anti-oxidant drugs which have not been ever used for OM, such as synthetic peptides as well as cell therapy with mesenchymal stem cells; amniotic membranes, mucoadhesive polymers loaded with anti-inflammatory agents and natural or synthetic electrospun. These approaches have been promising to allow the production of drug-loaded membranes, scaffolds for cells encapsulation or guided tissue regeneration.

A comprehensive guide to the pharmacologic regulation of angiotensin converting enzyme 2 (ACE2), the SARS-CoV-2 entry receptor

The recent emergence of coronavirus disease-2019 (COVID-19) as a global pandemic has prompted scientists to address an urgent need for defining mechanisms of disease pathology and treatment. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent for COVID-19, employs angiotensin converting enzyme 2 (ACE2) as its primary target for cell surface attachment and likely entry into the host cell. Thus, understanding factors that may regulate the expression and function of ACE2 in the healthy and diseased body is critical for clinical intervention. Over 66% of all adults in the United States are currently using a prescription drug and while earlier findings have focused on possible upregulation of ACE2 expression through the use of renin angiotensin system (RAS) inhibitors, mounting evidence suggests that various other widely administered drugs used in the treatment of hypertension, heart failure, diabetes mellitus, hyperlipidemias, coagulation disorders, and pulmonary disease may also present a varied risk for COVID-19. Specifically, we summarize mechanisms on how heparin, statins, steroids and phytochemicals, besides their established therapeutic effects, may also interfere with SARS-CoV-2 viral entry into cells. We also describe evidence on the effect of several vitamins, phytochemicals, and naturally occurring compounds on ACE2 expression and activity in various tissues and disease models. This comprehensive review aims to provide a timely compendium on the potential impact of commonly prescribed drugs and pharmacologically active compounds on COVID-19 pathology and risk through regulation of ACE2 and RAS signaling.

Olmesartan Prevents Oligomerized Amyloid β (Aβ)-Induced Cellular Senescence in Neuronal Cells

Alzheimer's disease (AD) is a neurodegenerative disease with high morbidity. The deposition of oligomerized amyloid β (Aβ) is the pathological feature of AD. The Aβ-caused neuronal oxidative stress and cellular senescence play an important role in the development and progression of AD. Olmesartan is a novel angiotensin receptor blocker with promising antihypertensive properties and has recently been reported to exert anti-inflammatory and antioxidative stress effects. Blood pressure control using Angiotensin receptor blockers has shown multiple benefits in Alzheimer's disease models. In the present study, the effect of Olmesartan on oligomerized amyloid β (Aβ)-induced cellular senescence was investigated in cultured M17 neuronal cells. Our results show that Olmesartan treatment significantly ameliorates oligomerized Aβ-elevated ROS and MDA levels, as well as the induced senescent cells number. At the molecular level, Olmesartan inhibits the elevated expression of senescence biomarkers (p16 and p21). Furthermore, Olmesartan potently reversed the increased K382 acetylation of p53 and the downregulation of SIRT1. Moreover, we show that the effect of Olmesartan against cell senescence and deacetylation of p53 was abolished by inhibition of SIRT1, either by using nicotinamide or by transfection with SIRT1 siRNA. In conclusion, Olmesartan prevents oligomerized Aβ-induced cellular senescence in neuronal cells by downregulating p16 and p21 through a SIRT1 dependent deacetylation of p53; our finding indicates that Olmesartan has a protective effect in Aβ-induced neurotoxicity.

Effect of Dexamethasone-Loaded PLGA Nanoparticles on Oral Mucositis Induced by 5-Fluorouracil

Oral mucositis (OM) is characterized by the presence of severe ulcers in the oral region that affects patients treated with chemotherapy. It occurs in almost all patients who receive radiotherapy of the head and neck, as well as patients who undergo hematopoietic cell transplantation. The pathophysiology of OM is complex, and there is no effective therapy. The aim of this study was to evaluate the effect of dexamethasone-loaded poly(d,l-Lactic-co-glycolic) nanoparticles (PLGA-DEX NPs) on an OM model induced in hamsters. The NPs were synthesized using the emulsification-solvent evaporation method and were characterized by the size, zeta potential, encapsulation efficiency, atomic force microscopy, physicochemical stability, and the in vitro release. The OM was induced by the administration of 5-FU on the first and second days and mechanical trauma on the 4th day of the experiment. PLGA-DEX NPs were administered to treat OM. The animals were euthanized on the 10th day. Macroscopic and histopathological analyses were performed, measurement of malonaldehyde (MDA) and ELISA was used to determine the levels of IL-1β and TNF-α. Immunoexpressions of NF-κB, COX-2, and TGF-β were determined by immunohistochemistry, and qRT-PCR was used to quantify the gene expression of the GILZ, MKP1, and NF-κB p65. The PLGA-DEX NPs (0.1 mg/kg) significantly reduced macroscopic and histopathological scores, decreased MDA, TNF-α and IL-1β levels, immunostaining for NF-κB, COX-2, TGF-β, and suppressed NF-κB p65 mRNA expression, but increased GILZ and MKP1 expression.

Salivary alpha-1-antitrypsin and macrophage migration inhibitory factor may be potential prognostic biomarkers for oncologic treatment-induced severe oral mucositis

AIMS

Evaluate the abundance of the selected targets, alpha-1-antitrypsin (A1AT) and macrophage migration inhibitory factor (MIF), and correlate these findings with the risk of developing severe oral mucositis (OM).

MATERIALS AND METHODS

Head and neck squamous cell carcinoma (HNSCC) patients submitted to radiotherapy (RT) or chemoradiotherapy (CRT) were assessed. OM grade and pain were evaluated daily during treatment. Two protein targets, A1AT and MIF, were evaluated, using selected reaction monitoring-mass spectrometry (SRM-MS), in whole saliva, collected prior to oncologic treatment. The results obtained from the targeted proteomic analysis were correlated with OM clinical outcomes.

RESULTS

A total of 27 patients were included, of whom 21 (77.8%) had locally advanced disease (clinical stage III or IV). Most patients (70.4%) received CRT. OM grades 2 (40.8%) and 3 (33.3%) were the most prevalent during RT with a mean highest reported OM-related pain of 3.22 through the visual analogue scale (VAS). The abundance of A1AT and MIF correlated significantly with severe (grades 3 or 4, p < 0.02) compared with moderate-low (grades 1 or 2, p < 0.04) OM grade.

CONCLUSIONS

There is a correlation between the abundance of salivary A1AT and MIF and oncologic treatment-induced OM. The correlation of MIF expression with severe OM appears to be compatible with its physiological pro-inflammatory role. These results open up great possibilities for the use of salivary MIF and A1AT levels as prognostic markers for effective therapeutic interventions, such as photobiomodulation therapy, patient-controlled analgesia, or personalized medicaments.

Currently prescribed drugs in the UK that could upregulate or downregulate ACE2 in COVID-19 disease: a systematic review

OBJECTIVE

To review evidence on routinely prescribed drugs in the UK that could upregulate or downregulate ACE2 and potentially affect COVID-19 disease.

DESIGN

Systematic review.

DATA SOURCE

MEDLINE, EMBASE, CINAHL, the Cochrane Library and Web of Science.

STUDY SELECTION

Any design with animal or human models examining a currently prescribed UK drug compared with a control, placebo or sham group, and reporting an effect on ACE2 level, activity or gene expression.

DATA EXTRACTION AND SYNTHESIS

MEDLINE, EMBASE, CINAHL, the Cochrane Library, Web of Science and OpenGrey from inception to 1 April 2020. Methodological quality was assessed using the SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) risk-of-bias tool for animal studies and Cochrane risk-of-bias tool for human studies.

RESULTS

We screened 3360 titles and included 112 studies with 21 different drug classes identified as influencing ACE2 activity. Ten studies were in humans and one hundred and two were in animal models None examined ACE2 in human lungs. The most frequently examined drugs were angiotensin receptor blockers (ARBs) (n=55) and ACE inhibitors (ACE-I) (n=22). More studies reported upregulation than downregulation with ACE-I (n=22), ARBs (n=55), insulin (n=8), thiazolidinedione (n=7) aldosterone agonists (n=3), statins (n=5), oestrogens (n=5) calcium channel blockers (n=3) glucagon-like peptide 1 (GLP-1) agonists (n=2) and Non-steroidal anti-inflammatory drugs (NSAIDs) (n=2).

CONCLUSIONS

There is an abundance of the academic literature and media reports on the potential of drugs that could attenuate or exacerbate COVID-19 disease. This is leading to trials of repurposed drugs and uncertainty among patients and clinicians concerning continuation or cessation of prescribed medications. Our review indicates that the impact of currently prescribed drugs on ACE2 has been poorly studied in vivo, particularly in human lungs where the SARS-CoV-2 virus appears to enact its pathogenic effects. We found no convincing evidence to justify starting or stopping currently prescribed drugs to influence outcomes of COVID-19 disease.

Effect of Gold Nanoparticle on 5-Fluorouracil-Induced Experimental Oral Mucositis in Hamsters

BACKGROUND

Oral mucositis (OM) is a severe inflammation of the oral mucosal cells associated with chemotherapy and/or radiotherapy-induced toxicity, resulting in epithelial ulcers and higher risk of death from sepsis. The aim of the present study was to evaluate the nanoparticle (AuNp) effect on OM induced in hamsters.

MATERIALS AND METHODS

5-fluorouracil (5FU) was used on the first and second day of the experimental model in Golden sirian hamsters, and on the fourth day, mechanical trauma was applied to induce OM. The animals were divided into groups, i.e., polyvinylpyrrolidone (PVP), mechanical trauma (MT), 5FU, and groups treated with gold nanoparticles (AuNps) (62.5, 125, and 250 μg/kg). On the 10th day, animals were euthanized for macroscopic, histopathological, immunohistochemical, western blot, quantitative polymerase chain reaction (qRT-PCR), and AuNp quantification.

RESULTS

AuNp (250 μg/kg) reduced TNF-α, IL-1β, COX-2, NF-κB, TGF-β, and SMAD 2/3; increased glutathione levels; decreased the expression of Kelch ECH-associated protein 1 (KEAP1); and induced heme oxygenase 1 (HMOX-1) and NAD (P) H quinone oxidoreductase 1 (NQO1) genes.

CONCLUSIONS

AuNp (250 μg/kg) prevented 5-FU-induced OM in hamsters and improved the parameters of inflammation and oxidative stress.