Long-term dexamethasone treatment diminishes store-operated Ca2+ entry in salivary acinar cells

Retroductal dexamethasone administration promotes the recovery from obstructive and inflammatory salivary gland dysfunction

Introduction

Salivary gland dysfunction, often resulting from salivary gland obstruction-induced inflammation, is a prevalent condition. Corticosteroid, known for its anti-inflammatory and immunomodulatory properties, is commonly prescribed in clinics. This study investigates the therapeutic implications and potential side effects of dexamethasone on obstructive sialadenitis recovery using duct ligation mice and salivary gland organoid models.

Methods

Functional and pathological changes were assessed after administering dexamethasone to the duct following deligation 2 weeks after maintaining ligation of the mouse submandibular duct. Additionally, lipopolysaccharide- and tumor necrosis factor-induced salivary gland organoid inflammation models were established to investigate the effects and underlying mechanisms of action of dexamethasone.

Results

Dexamethasone administration facilitated SG function restoration, by increasing salivary gland weight and saliva volume while reducing saliva lag time. Histological evaluation revealed, reduced acinar cell atrophy and fibrosis with dexamethasone treatment. Additionally, dexamethasone suppressed pro-inflammatory cytokines IL-1β and TNF expression. In a model of inflammation in salivary gland organoids induced by inflammatory substances, dexamethasone restored acinar markers such as AQP5 gene expression levels, while inhibiting pro-inflammatory cytokines TNF and IL6, as well as chemokines CCL2, CXCL5, and CXCL12 induction. Macrophages cultured in inflammatory substance-treated media from salivary gland organoid cultures exhibited pro-inflammatory polarization. However, treatment with dexamethasone shifted them towards an anti-inflammatory phenotype by reducing M1 markers (Tnf, Il6, Il1b, and Cd86) and elevating M2 markers (Ym1, Il10, Cd163, and Klf4). However, high-dose or prolonged dexamethasone treatment induced acino-ductal metaplasia and had side effects in both in vivo and in vitro models.

Conclusions

Our findings suggest the effectiveness of corticosteroids in treating obstructive sialadenitis-induced salivary gland dysfunction by regulating pro-inflammatory cytokines.

The effect of dental material type and masticatory forces on periodontitis-derived subgingival microbiomes

Restorative dental materials can frequently extend below the gingival margin, serving as a potential haven for microbial colonization, and altering the local oral microbiome to ignite infection. However, the contribution of dental materials on driving changes of the composition of the subgingival microbiome is under-investigated. This study evaluated the microbiome-modulating properties of three biomaterials, namely resin dental composites (COM), antimicrobial piezoelectric composites (BTO), and hydroxyapatite (HA), using an optimized in vitro subgingival microbiome model derived from patients with periodontal disease. Dental materials were subjected to static or cyclic loading (mastication forces) during biofilm growth. Microbiome composition was assessed by 16S rRNA gene sequencing. Dysbiosis was measured in terms of subgingival microbial dysbiosis index (SMDI). Biomaterials subjected to cyclic masticatory loads were associated with enhanced biofilm viability except on the antibacterial composite. Biomaterials held static were associated with increased biofilm biomass, especially on HA surfaces. Overall, the microbiome richness (Chao index) was similar for all the biomaterials and loading conditions. However, the microbiome diversity (Shannon index) for the HA beams was significantly different than both composites. In addition, beta diversity analysis revealed significant differences between composites and HA biomaterials, and between both loading conditions (static and cyclic). Under static conditions, microbiomes formed over HA surfaces resulted in increased dysbiosis compared to composites through the enrichment of periopathogens, including Porphyromonas gingivalis, Porphyromonas endodontalis, and Fretibacterium spp., and depletion of commensals such as Granulicatella and Streptococcus spp. Interestingly, cyclic loading reversed the dysbiosis of microbiomes formed over HA (depletion of periopathogenes) but increased the dysbiosis of microbiomes formed over composites (enrichment of Porphyromonas gingivalis and Fusobacterim nucleatum). Comparison of species formed on both composites (control and antibacterial) showed some differences. Commercial composites enriched Selenomonas spp. and depleted Campylobacter concisus. Piezoelectric composites effectively controlled the microbiome viability without significantly impacting the species abundance. Findings of this work open new understandings of the effects of different biomaterials on the modulation of oral biofilms and the relationship with oral subgingival infections.

Sialocele and Its Association with Hypercortisolism and Long-Term Glucocorticoid Treatment in Dogs: Retrospective Case-Control Study

Dogs with sialocele often have concurrent hypercortisolism or are receiving long-term glucocorticoid treatment. However, their association has not been investigated. This retrospective matched case-control study investigated the association between hypercortisolism, long-term glucocorticoid treatment, and sialocele in dogs. We retrospectively reviewed the records from 1 January 2018 to 31 December 2022. Records of 19 dogs diagnosed with sialocele were investigated for hypercortisolism and long-term glucocorticoid treatment. Two age- and breed-matched controls for each sialocele dog (38 dogs) were investigated for the same concurrent diseases. Logistic regression analysis was used. The odds of sialocele in dogs with hypercortisolism were 15.56 times those of dogs without hypercortisolism (p = 0.02; 95% CI: 1.54-156.79). The odds of sialocele in dogs with long-term glucocorticoid treatment (median, 8 months; range, 5-13) were 7.78 times those of dogs without long-term glucocorticoid treatment (p = 0.03; 95% CI: 1.23-49.40). No associations were found between age, sex, body weight, and the presence of sialocele. The results indicate that sialocele was significantly associated with hypercortisolism and long-term glucocorticoid treatment in dogs. Therefore, dogs with hypercortisolism or receiving long-term glucocorticoid therapy should be screened for possible sialocele. Additionally, dogs with sialocele should be identified for concurrent hypercortisolism and prolonged glucocorticoid exposure.

Potential targets of phytochemical immunomodulatory therapy in periodontitis immunopathogenesis: A narrative review

Introduction

Periodontitis is one of the most prevalent diseases occurring worldwide, and is caused by an imbalance of host immunological defenses and microbiome profile which occurs in the oral cavity. This imbalance leads to irregularity and uncontrolled activities of immune cells, resulting in over-reactivity of periodontopathogens and tissue destruction. To alleviate periodontitis, exact targeting of specific events involving particular cells could be a potential application of immunomodulatory agents. Phytochemical drug development targeting specific immunopathogenesis events could be a promising complementary, alternative approach to periodontal therapy.

Objectives

This review aimed to explore various events involving a variety of cells in the immunopathogenesis of periodontitis in order to determine potential specific immunomodulation targets for future development of effective phytochemical drugs.

Results

Immunopathogenesis of periodontitis contributes significantly to the disease onset and resolution. Various events occur during the disease development, which involve a variety of immune cells and mediators. Among these, neutrophils, cytokines and lymphocytes, especially Th17 cells, were reported to be the most relevant components in the disease pathogenesis. These components affect the initial responses to periodontopathogens, inhibit oxidative stress formation, control intercellular communication to enhance inflammation, and promote effector cells' migration to induce alveolar bone resorption. Several phytochemical drugs were developed to cure periodontitis, however, the development of phytochemical immunomodulatory drugs to target specific events has not been realized.

Conclusion

This review concluded that development of phytochemical immunomodulatory drugs to target particular events generated by neutrophils, pro-inflammatory cytokines and lymphocytes has tremendous potential to regulate and modulate the immunopathogenesis of periodontitis.

A novel lncRNA-mediated epigenetic regulatory mechanism in periodontitis

Periodontitis is a highly prevalent chronic inflammatory disease with an exaggerated host immune response, resulting in periodontal tissue destruction and potential tooth loss. The long non-coding RNA, LncR-ANRIL, located on human chromosome 9p21, is recognized as a genetic risk factor for various conditions, including atherosclerosis, periodontitis, diabetes, and cancer. LncR-APDC is an ortholog of ANRIL located on mouse genome chr4. This study aims to comprehend the regulatory role of lncR-APDC in periodontitis progression. Our experimental findings, obtained from lncR-APDC gene knockout (KO) mice with induced experimental periodontitis (EP), revealed exacerbated bone loss and disrupted pro-inflammatory cytokine regulation. Downregulation of osteogenic differentiation occurred in bone marrow stem cells harvested from lncR-APDC-KO mice. Furthermore, single-cell RNA sequencing of periodontitis gingival tissue revealed alterations in the proportion and function of immune cells, including T and B cells, macrophages, and neutrophils, due to lncR-APDC silencing. Our findings also unveiled a previously unidentified epithelial cell subset that is distinctively presenting in the lncR-APDC-KO group. This epithelial subset, characterized by the positive expression of Krt8 and Krt18, engages in interactions with immune cells through a variety of ligand-receptor pairs. The expression of Tff2, now recognized for its role in chronic inflammatory conditions, exhibited a notable increase across various tissue and cell types in lncR-APDC deficient mice. Additionally, our investigation revealed the potential for a direct binding interaction between lncR-APDC and Tff2. Intra-gingival administration of AAV9-lncR-APDC was shown to have therapeutic effects in the EP model. In conclusion, our results suggest that lncR-APDC plays a critical role in the progression of periodontal disease and holds therapeutic potential for periodontitis. Furthermore, the presence of the distinctive epithelial subpopulation and significantly elevated Tff2 levels in the lncR-APDC-silenced EP model offer new perspectives on the epigenetic regulation of periodontitis pathogenesis.

Comparison of the Shear Bond Strength of Orthodontic Composites Containing Silver and Amorphous Tricalcium Phosphate Nanoparticles: an ex vivo Study

Statement of the Problem

It is important to use orthodontic composites with favorable properties, which are easily removed after the end of the treatment but not easily debonded during treatment. Nanoparticles have drawn attention for their antibacterial properties when added to composite resins. However, the effect of addition of nanoparticle on shear bond strength is not broadly discussed.

Purpose

The present study was designed to compare the shear bond strength of orthodontic brackets bonded by orthodontic composite containing silver nanoparticles with orthodontic composite containing amorphous tricalcium phosphate nanoparticles.

Materials and Method

In this ex vivo study, 36 sound extracted human premolars were used and randomly divided into three groups. The brackets were bonded in the first group by composite without nanoparticles, in the second group by composite containing 3% amorphous tricalcium phosphate nanoparticles and in the third group by composite containing 0.3% silver nanoparticles at the buccal surface of the teeth. The shear bond strengths of the samples were measured 24 hours after preparation by a universal testing machine. Data were analyzed using SPSS 21 software through one-way ANOVA and Tamhane's T2 multiple comparison tests. pValues under 0.05 were considered significant.

Results

There was no significant difference between the mean shear bond strength of composite containing amorphous tricalcium phosphate nanoparticles with composite without nanoparticles (p= 0.142). However, the mean shear bond strength in the composite containing silver nanoparticles was significantly lower than the other two groups (p< 0.001).

Conclusion

According to the results of this study, the addition of amorphous tricalcium phosphate nanoparticles to orthodontic composite does not significantly decrease the shear bond strength while silver nanoparticles reduce the shear bond strength of orthodontic composite.

How Does the First Molar Root Location Affect the Critical Stress Pattern in the Periodontium? A Finite Element Analysis

Statement of the Problem

The first molar root location plays a pivotal role in neutralization of forces applied to the teeth to prevent injury.

Purpose

This study aimed to assess the effect of maxillary and mandibular first molar root location on biomechanical behavior of the periodontium under vertical and oblique loadings.

Materials and Method

In this three-dimensional (3D) finite element analysis (FEA), the maxillary and mandibular first molars and their periodontium were modeled. The Young's modulus and the Poisson's ratio for the enamel, dentin, dental pulp, periodontal ligament (PDL), and cortical and cancellous bones were adopted from previous studies. The changes in maximum von Misses stress (MVMS) values of each component were analyzed.

Results

The MVMS values were the highest in the enamel followed by dentin, cortical bone, cancellous bone, and PDL. The maxillary and mandibular first molars with different root locations and their periodontium showed different biomechanical behaviors under the applied loads.

Conclusion

An interesting finding was that the stress concentration point in the path of load degeneration changed from the cervical third in dentin to the apical third in the cancellous bone, which can greatly help in detection of susceptible areas over time.

Human periodontitis-associated salivary microbiome affects the immune response of diabetic mice

Background

The bidirectional association between periodontitis and diabetes mellitus has been well accepted; however, pathways connecting them remain unclear. Some oral bacteria are able to induce immunologic changes favoring insulin resistance individually. However, it is unclear if and how the systemic immune system responds to a disturbed oral microbial community in diabetic sufferers.

Aim

This study aimed to investigate the impact of the human periodontitis-associated salivary microbiome on the splenic immune responses of diabetic mice.

Methods

An in vivo diabetic animal model was established by feeding high fat food. After microbial depletion with quadruple antibiotic treatment, human saliva from healthy and periodontitis volunteers was transplanted into the mouth of these diabetic mice (N = 3), respectively.

Results

Osteoclasts and expression levels of TNF-α and IL-1β were significantly increased in periodontal tissues of mice receiving periodontitis patients donated microbiome compared to these transplanted with healthy subjects donated microbiome. The proportion of monocyte (an innate immunocyte) decreased in mice receiving periodontitis patients donated microbiome. However, the abundance of an adaptive immunocyte Th17 was up-regulated. The IL17 production of ILC3 cells in human periodontitis-associated salivary microbiome recipient mice was significantly impaired.

Conclusions

A disturbed oral microbiome imposes a stress on the splenic immune responses of diabetic mice.

A combination treatment of low-dose dexamethasone and aspirin-triggered resolvin D1 reduces Sjögren syndrome-like features in a mouse model

Background

Sjögren syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration and diminished secretory function of the salivary glands. Dexamethasone (DEX) resolves dry mouth and lymphocytic infiltration; however, this treatment is difficult to maintain because of multiple adverse effects (eg, osteoporosis and skin thinning); likewise, aspirin-triggered resolvin D1 (AT-RvD1) increases saliva secretion but cannot eliminate lymphocytic infiltration. Previous studies showed that a combination of low-dose DEX with AT-RvD1 before disease onset prevents SS-like features in a mouse model; however, this is not clinically practical because there are no reliable indicators of SS before disease onset. Therefore, the authors applied the combined treatment at disease onset to show its efficacy and comparative lack of adverse effects, so that it may reasonably be maintained over a patient's lifetime.

Methods

NOD/ShiLtJ mice were treated with ethanol (vehicle control), high-dose DEX alone, AT-RvD1 alone, or a combination of low-dose DEX with AT-RvD1 at disease onset for 8 weeks. Then saliva flow rates were measured, and submandibular glands were harvested for histologic analyses.

Results

A combined treatment of low-dose DEX with AT-RvD1 significantly decreased mast cell degranulation and lymphocytic infiltration, increased saliva secretion, and restored apical aquaporin-5 expression in submandibular glands of NOD/ShiLtJ mice.

Conclusions

Low-dose DEX combined with AT-RvD1 reduces the severity of SS-like manifestation and prevents the development of advanced and potentially irreversible damage, all in a form that can reasonably be administered indefinitely without the need to cease treatment because of secondary effects.

Evaluation of Salivary KCNJ3 mRNA Levels in Breast Cancer: A Case–control Study and in silico Analysis

Background:

Breast cancer (BC) is considered the most malignant and central cancer-related death among women worldwide. There is an essential need to discover new methods for developing noninvasive and low-cost diagnoses. The present study examines the expression of KCNJ3 which acts as a biomarker for detecting BC in the saliva of BC patients compared to controls.

Methods:

The mRNA expression level of KCNJ3 has been evaluated. Forty-three unstimulated whole saliva samples from BC patients and forty-three salivary samples from healthy controls were collected. The mRNA level was measured using quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, the protein-protein interaction network in which KCNJ3 is involved was obtained. In silico analysis was applied to predict the possible molecular mechanisms of KCNJ3 in BC development.

Results:

Differentially expressed KCNJ3 was statistically significant between BC patients and controls (p<0.001). The sensitivity and specificity of KCNJ3 mRNA in BC detection were 76.74% and 94.95%, respectively. Receiver operating characteristic (ROC) curve analysis of KCNJ3 mRNA revealed that Area under the curve (AUC) was 0.923 (95% Confidence Interval (CI): 0.866-0.979). AUCs of ROC curve analysis were 0.743 (95% CI: 0.536-0.951), 0.685 (95% CI: 0.445-0.925), and 0.583(95% CI: 0.343-0.823) for differentiation stage I from stage III, stage I to stage II and finally stage II from stage III, respectively. Furthermore, the GABAergic synapse signaling pathway was suggested as a potential pathway involved in BC development.

Conclusion:

Salivary levels of KCNJ3 could be considered a potential diagnostic biomarker with high sensitivity and specificity for BC detection.

Comparative evaluation of incorporation calcium silicate and calcium phosphate nanoparticles on biomimetic dentin remineralization and bioactivity in an etch-and-rinse adhesive system

BACKGROUND

This study aimed to evaluate the remineralization potential and bioactivity of adhesives, containing amorphous calcium phosphate (ACP) and calcium silicate (CS) nanoparticles (NPs).

MATERIAL AND METHODS

In this study, dentin slices (n=60) were prepared and etched with phosphoric acid. Next, they were divided into two groups: pre- and post-immersion in a simulated body fluid (SBF) for three weeks. The two groups were also divided into five subgroups (n=6 per subgroup), including the control (0 wt.% NPs); adhesives containing 1 wt.% and 2.5 wt.% (CS) nanoparticles; and adhesives containing 1 wt.% and 2.5 wt.% ACP nanoparticles. The remineralization potential and bioactivity of the adhesives were evaluated. The shear bond strength of the samples (n=18) was also assessed using a universal testing machine.

RESULTS

The present results revealed that the adhesive containing ACP and CS nanoparticles showed bioactivity and remineralization potential without any reduction in the bond strength.

CONCLUSIONS

The outcomes revealed that Cs and ACP nanoparticles induced mineralization in the dentin and incorporation of these nanoparticles to dentin bonding agents could improve the bio-functionalization of dentin bond. Key words:Calcium phosphate, calcium silicate, fourier transform infrared spectroscopy, scanning electron microscopy, tooth remineralization.

Construction of biomimetic cell-sheet-engineered periosteum with a double cell sheet to repair calvarial defects of rats

Background

The periosteum plays a crucial role in the development and injury healing process of bone. The purpose of this study was to construct a biomimetic periosteum with a double cell sheet for bone tissue regeneration.

Methods

In vitro, the human amniotic mesenchymal stem cells (hAMSCs) sheet was first fabricated by adding 50 ​μg/ml ascorbic acid to the cell sheet induction medium. Characterization of the hAMSCs sheet was tested by general observation, microscopic observation, live/dead staining, scanning electron microscopy (SEM) and hematoxylin and eosin (HE) staining. Afterwards, the osteogenic cell sheet and vascular cell sheet were constructed and evaluated by general observation, alkaline phosphatase (ALP) staining, Alizarin Red S staining, SEM, live/dead staining and CD31 immunofluorescent staining for characterization. Then, we prepared the double cell sheet. In vivo, rat calvarial defect model was introduced to verify the regeneration of bone defects treated by different methods. Calvarial defects (diameter: 4 ​mm) were created of Sprague–Dawley rats. The rats were randomly divided into 4 groups: the control group, the osteogenic cell sheet group, the vascular cell sheet group and the double cell sheet group. Macroscopic, micro-CT and histological evaluations of the regenerated bone were performed to assess the treatment results at 8 weeks and 12 weeks after surgery.

Results

In vitro, hAMSCs sheet was successfully prepared. The hAMSCs sheet consisted of a large number of live hAMSCs and abundant extracellular matrix (ECM) that secreted by hAMSCs, as evidenced by macroscopic/microscopic observation, live/dead staining, SEM and HE staining. Besides, the osteogenic cell sheet and the vascular cell sheet were successfully prepared, which were verified by general observation, ALP staining, Alizarin Red S staining, SEM and CD31 immunofluorescent staining. In vivo, the macroscopic observation and micro-CT results both demonstrated that the double cell sheet group had better effect on bone regeneration than other groups. In addition, histological assessments indicated that large amounts of new bone had formed in the calvarial defects and more mature collagen in the double cell sheet group.

Conclusion

The double cell sheet could promote to repair calvarial defects of rats and accelerate bone regeneration.

The translational potential of this article

We successfully constructed a biomimetic cell-sheet-engineered periosteum with a double cell sheet by a simple, low-cost and effective method. This biomimetic periosteum may be a promising therapeutic strategy for the treatment of bone defects, which may be used in clinic in the future.

Healing Field: Using Alternating Electric Fields to Prevent Cytokine Storm by Suppressing Clonal Expansion of the Activated Lymphocytes in the Blood Sample of the COVID-19 Patients

In the case of the COVID-19 early diagnosis, numerous tech innovations have been introduced, and many are currently employed worldwide. But, all of the medical procedures for the treatment of this disease, up to now, are just limited to chemical drugs. All of the scientists believe that the major challenge toward the mortality of the COVID-19 patients is the out-of-control immune system activation and the subsequent cytokine production. During this process, the adaptive immune system is highly activated, and many of the lymphocytes start to clonally expand; hence many cytokines are also released. So, any attempt to harness this cytokine storm and calm down the immune outrage is appreciated. While the battleground for the immune hyperactivation is the lung ambient of the infected patients, the only medical treatment for suppressing the hypercytokinemia is based on the immunosuppressor drugs that systemically dampen the immunity with many unavoidable side effects. Here, we applied the alternating electric field to suppress the expansion of the highly activated lymphocytes, and by reducing the number of the renewed cells, the produced cytokines were also decreased. Applying this method to the blood of the COVID-19 patients in vitro showed ∼33% reduction in the average concentration of the three main cytokines after 4 days of stimulation. This method could carefully be utilized to locally suppress the hyperactivated immune cells in the lung of the COVID-19 patients without any need for systemic suppression of the immune system by the chemical drugs.

Diagnostic Accuracy of Salivary Biomarkers in Detecting Early Oral Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

Biopsy is the gold standard for oral squamous cell carcinoma (OSCC) diagnosis. Salivary biomarkers provide promising complementary alternative diagnostic adjunct for its simple non- invasive collection and technique and to screen large population.

OBJECTIVE

To summarize and compare the existing evidence on diagnostic accuracy of salivary biomarkers with their estimation method in detecting early oral squamous cell carcinoma.

METHODS

The review protocol is registered under PROSPERO(CRD42021225704). PubMed, Google Scholar, EBSCOhost were searched from 2000 to 2020 to identify the screening potential of eight salivary biomarkers: mRNA, miRNA, DUSP100, s100P, IL-8, IL-1B, TNF-a and MMP-9. True-positive, false-positive, true-negative, false-negative, sensitivity, specificity values were extracted or calculated if not present for each study. Quality of selected studies was evaluated based on QUADAS 2 tool. Meta-analysis was performed using a bivariate model parameter for the sensitivity and specificity and summary points, summary receiver operating curve (SROC), confidence region, and prediction region were calculated.

RESULTS

Eighteen studies were included for qualitative synthesis and out of that 13 for meta-analysis. Sensitivity and specificity were calculated with AUC. For mRNA it was 91% and 90% with 0.96 AUC, miRNA had 91% and 91% with 0.95 AUC for PCR. IL-1B had 46% and 60% with 0.61 AUC, S100p had 45% and 90% with 0.57 AUC for ELISA. IL-8 had 54% and 74% for ELISA and 89% and 90% for PCR with 0.79 AUC and DUSP1 had 32% and 87% for ELISA and 76% and 83% for PCR with 0.83 AUC respectively.

CONCLUSION

Early detection of OSCC was best achieved by screening for salivary mRNA and miRNA estimated by PCR. Further investigation is required into salivary RNA as novel biomarkers and these salivary biomarkers may be potentially used for non-invasive diagnosis of early OSCC.

Dexamethasone Administration in Mice Leads to Less Body Weight Gain over Time, Lower Serum Glucose, and Higher Insulin Levels Independently of NRF2

Glucocorticoids are used widely on a long-term basis in autoimmune and inflammatory diseases. Their adverse effects include the development of hyperglycemia and osteoporosis, whose molecular mechanisms have been only partially studied in preclinical models. Both these glucocorticoid-induced pathologies have been shown to be mediated at least in part by oxidative stress. The transcription factor nuclear erythroid factor 2-like 2 (NRF2) is a central regulator of antioxidant and cytoprotective responses. Thus, we hypothesized that NRF2 may play a role in glucocorticoid-induced metabolic disease and osteoporosis. To this end, WT and Nrf2 knockout (Nrf2KO) mice of both genders were treated with 2 mg/kg dexamethasone or vehicle 3 times per week for 13 weeks. Dexamethasone treatment led to less weight gain during the treatment period without affecting food consumption, as well as to lower glucose levels and high insulin levels compared to vehicle-treated mice. Dexamethasone also reduced cortical bone volume and density. All these effects of dexamethasone were similar between male and female mice, as well as between WT and Nrf2KO mice. Hepatic NRF2 signaling and gluconeogenic gene expression were not affected by dexamethasone. A 2-day dexamethasone treatment was also sufficient to increase insulin levels without affecting body weight and glucose levels. Hence, dexamethasone induces hyperinsulinemia, which potentially leads to decreased glucose levels, as well as osteoporosis, both independently of NRF2.

The microbiota-related coinfections in COVID-19 patients: a real challenge

BACKGROUND

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of ongoing global pandemic of coronavirus disease 2019 (COVID-19), has infected millions of people around the world, especially the elderly and immunocompromised individuals. The infection transmission rate is considered more rapid than other deadly pandemics and severe epidemics encountered earlier, such as Ebola, Zika, Influenza, Marburg, SARS, and MERS. The public health situation therefore is really at a challenging crossroads.

MAIN BODY

The internal and external and resident microbiota community is crucial in human health and is essential for immune responses. This community tends to be altered due to pathogenic infections which would lead to severity of the disease as it progresses. Few of these resident microflora become negatively active during infectious diseases leading to coinfection, especially the opportunistic pathogens. Once such a condition sets in, it is difficult to diagnose, treat, and manage COVID-19 in a patient.

CONCLUSION

This review highlights the various reported possible coinfections that arise in COVID-19 patients vis-à-vis other serious pathological conditions. The local immunity in lungs, nasal passages, oral cavity, and salivary glands are involved with different aspects of COVID-19 transmission and pathology. Also, the role of adaptive immune system is discussed at the site of infection to control the infection along with the proinflammatory cytokine therapy.