Immunomodulatory and Antiviral Activity of Metformin and Its Potential Implications in Treating Coronavirus Disease 2019 and Lung Injury

The Effect of Antihyperglycemic Medications on COVID-19: A Meta-analysis and Systematic Review from Observational Studies

BACKGROUND

Diabetes, a chronic disease worldwide, may be associated with a poorer prognosis in patients with coronavirus disease 2019 (COVID-19). While some antihyperglycemic medications may be beneficial, others may increase the risk of adverse clinical outcomes of COVID-19. We aimed to analyze the effect of antihyperglycemic medications on COVID-19.

METHODS

We searched the Web of Science, Cochrane Library, EMBASE, PubMed, and Scopus databases from December 2019 to June 2022 to identify literature related to patients with COVID-19 and type 2 diabetes mellitus (T2DM) treated with antihyperglycemic medications.

RESULTS

56 studies were included in the analysis. Metformin (OR 0.66; 95% CI 0.58-0.74; p < 0.05), Glucagon-like peptide-1 receptor agonist (GLP-1ra) (OR 0.73; 95% CI 0.59-0.91; p < 0.05), and sodium-dependent glucose transporters 2 inhibitor (SGLT 2i) (OR 0.77; 95% CI 0.69-0.87; p < 0.05) were associated with lower mortality risk, while insulin was associated with increased mortality risk (OR 1.40; 95% CI 1.26-1.55; p < 0.05). Meanwhile, metformin (OR 0.65; 95% CI 0.50-0.85; p < 0.05) and GLP-1ra (OR 0.84; 95% CI 0.76-0.94; p < 0.05) were significantly associated with decreased severe manifestation risk. What's more, metformin (OR 0.77; 95% CI 0.62-0.96; p < 0.05), GLP-1ra (OR 0.86; 95% CI 0.81-0.92; p < 0.05), and SGLT 2i (OR 0.87; 95% CI 0.79-0.97; p < 0.05) were also associated with a decreased risk of hospitalization, but insulin were associated with an increased risk of hospitalization (OR 1.31; 95% CI 1.12-1.52; p < 0.05). Nevertheless, the results of the subgroup analyses showed that the effects of different glucose-lowering agents on COVID-19 may be related to in-hospital use or out-hospital use, elderly or non-elderly patients use, and different geography.

CONCLUSION

Metformin, GLP-1ra, and SGLT 2i have shown a positive effect on clinical outcomes in COVID-19, particularly in non-elderly individuals. However, insulin use may pose a higher risk, especially in elderly patients, so need with caution. Meanwhile, DPP-4i, TZD, α-GLUi, and sulfonylureas appeared to have a neutral effect. These results need to be validated in future clinical studies.

Metformin use associated with lower rate of hospitalization for influenza in individuals with diabetes

AIM

To investigate if patients with diabetes taking metformin have better outcomes versus those not taking metformin following an emergency room visit for influenza.

METHODS

Using electronic medical records, we performed a retrospective chart review of all adult patients with a diagnosis of diabetes seen in any Duke University Medical Center-affiliated emergency department for influenza over a 6-year period. We documented patient characteristics and comorbidities, and compared outcomes for patients taking metformin versus patients not taking metformin using both univariable and multivariable analyses. Our primary outcome was hospital admission rate. Secondary outcomes were in-hospital length of stay and in-hospital death.

RESULTS

Our cohort included 1023 adult patients with diabetes, of whom 59.9% were female. The mean age was 62.9 years, 58.4% were African American, 36.1% were White, and 81.9% were obese or overweight. Of these patients, 347 (34%) were taking metformin. Patients with diabetes taking metformin were less likely to be hospitalized following an emergency department visit for influenza than patients with diabetes not taking metformin (56.8% vs. 70.1%; p < 0.001). Of those patients admitted, there was no statistically significant difference in length of stay or death.

CONCLUSIONS

In patients with diabetes, metformin use is associated with lower rate of hospitalization following an emergency department visit for influenza.

A Dual Pharmacological Strategy against COVID-19: The Therapeutic Potential of Metformin and Atorvastatin

Metformin (MET) and atorvastatin (ATO) are promising treatments for COVID-19. This review explores the potential of MET and ATO, commonly prescribed for diabetes and dyslipidemia, respectively, as versatile medicines against SARS-CoV-2. Due to their immunomodulatory and antiviral capabilities, as well as their cost-effectiveness and ubiquitous availability, they are highly suitable options for treating the virus. MET's effect extends beyond managing blood sugar, impacting pathways that can potentially decrease the severity and fatality rates linked with COVID-19. It can partially block mitochondrial complex I and stimulate AMPK, which indicates that it can be used more widely in managing viral infections. ATO, however, impacts cholesterol metabolism, a crucial element of the viral replicative cycle, and demonstrates anti-inflammatory characteristics that could modulate intense immune reactions in individuals with COVID-19. Retrospective investigations and clinical trials show decreased hospitalizations, severity, and mortality rates in patients receiving these medications. Nevertheless, the journey from observing something to applying it in a therapeutic setting is intricate, and the inherent diversity of the data necessitates carefully executed, forward-looking clinical trials. This review highlights the requirement for efficacious, easily obtainable, and secure COVID-19 therapeutics and identifies MET and ATO as promising treatments in this worldwide health emergency.

Metformin inhibits paclitaxel-induced mechanical allodynia by activating opioidergic pathways and reducing cytokines production in the dorsal root ganglia and thalamus

It has been shown that AMP-activated protein kinase (AMPK) is involved in the nociceptive processing. This observation has prompted us to investigate the effects of the AMPK activator metformin on the paclitaxel-induced mechanical allodynia, a well-established model of neuropathic pain. Mechanical allodynia was induced by four intraperitoneal (i.p) injections of paclitaxel (2 mg/kg.day) in mice. Metformin was administered per os (p.o.). Naltrexoneandglibenclamide were used to investigate mechanisms mediating metformin activity. Concentrations of cytokines in the dorsal root ganglia (DRG) and thalamus were determined. After a single p.o. administration, the two highest doses of metformin (500 and 1000 mg/kg) attenuated the mechanical allodynia. This response was attenuated by all doses of metformin (250, 500 and 1000 mg/kg) when two administrations, 2 h apart, were carried out. Naltrexone (5 and 10 mg/kg, i.p.), but not glibenclamide (20 and 40 mg/kg, p.o.), attenuated metformin activity. Concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and CXCL-1 in the DRG were increased after administration of paclitaxel. Metformin (1000 mg/kg) reduced concentrations of TNF-α, IL-1β and CXCL-1 in the DRG. Concentration of IL-6, but not TNF-α, in the thalamus was increased after administration of paclitaxel. Metformin (1000 mg/kg) reduced concentration of IL-6 in the thalamus. In summary, metformin exhibits activity in the model of neuropathic pain induced by paclitaxel. This activity may be mediated by activation of opioidergic pathways and reduced production of TNF-α, IL-1β and CXCL-1 in the DRG and IL-6 in the thalamus.

The F/B ratio as a biomarker for inflammation in COVID-19 and T2D: Impact of metformin

The pandemic of COVID-19 has highlighted the intricate relationship between gut microbiome and overall health. Recent studies have shown that the Firmicutes/Bacteroidetes ratio in the gut microbiome may be linked to various diseases including COVID-19 and type 2 diabetes (T2D). Understanding the link between gut microbiome and these diseases is essential for developing strategies for prevention and treatment. In this study, 115 participants were recruited and divided into three groups: 1st group: T2D patients and healthy controls, 2nd group: COVID-19 patients with and without T2D, 3rd group: T2D patients with COVID-19 treated with or without metformin. Gut microbial composition at the phylum level was assessed using qRT-PCR with universal primers targeting the bacterial 16 S rRNA gene and specific primers for Firmicutes and Bacteroidetes. Data was analyzed using one-way ANOVA, logistic regression, and Spearman's rank correlation coefficient. The study found that the ratio of Firmicutes to Bacteroidetes (F/B) was higher in patients with both T2D and COVID-19 compared to those with only T2D or COVID-19. Additionally, the F/B ratio was positively correlated with C-reactive protein (CRP) in T2D and COVID-19 patients. The study also suggests that metformin treatment may affect this correlation. Logistic regression analysis showed that the F/B ratio was significantly associated with CRP. These findings suggest that the F/B ratio may be a potential biomarker for inflammation in T2D and COVID-19 patients and metformin treatment may have an effect on the correlation between F/B and CRP levels.

Metformin in COVID-19: Is There a Role Beyond Glycemic Control?

Context

The coronavirus disease 2019 (COVID-19) pandemic is still a cause of worldwide health concern. Diabetes and its associated comorbidities are risk factors for mortality and morbidity in COVID-19. Selecting the right antidiabetic drug to achieve optimal glycemic control might mitigate some of the negative impacts of diabetes. Metformin continues to be the most widely administered antidiabetic agent. There is evidence of its beneficial outcome in COVID-19 independent of its glucose-lowering effect.

Evidence Acquisition

A thorough literature search was conducted in PubMed, Google Scholar, Scopus, and Web of Science to identify studies investigating metformin in COVID-19.

Results

Several overlapping mechanisms have been proposed to explain its antiviral properties. It could bring about conformational changes in the angiotensin-converting enzyme-2 receptor and decrease viral entry. The effects on the mammalian target of the rapamycin pathway and cellular pH have been proposed to reduce viral protein synthesis and replication. The immunomodulatory effects of metformin might counter the detrimental effects of hyperinflammation associated with COVID-19.

Conclusions

These findings call for broader metformin usage to manage hyperglycemia in COVID-19.

Metformin suppresses SARS-CoV-2 in cell culture

Comorbidities such as diabetes worsen COVID-19 severity and recovery. Metformin, a first-line medication for type 2 diabetes, has antiviral properties and certain studies have also indicated its prognostic potential in COVID-19. Here, we report that metformin significantly inhibits SARS-CoV-2 growth in cell culture models. First, a steady increase in AMPK phosphorylation was detected as infection progressed, suggesting its important role during viral infection. Activation of AMPK in Calu3 and Caco2 cell lines using metformin revealed that metformin suppresses SARS-CoV-2 infectious titers up to 99%, in both naïve as well as infected cells. IC50 values from dose-variation studies in infected cells were found to be 0.4 and 1.43 mM in Calu3 and Caco2 cells, respectively. Role of AMPK in metformin's antiviral suppression was further confirmed using other pharmacological compounds, AICAR and Compound C. Collectively, our study demonstrates that metformin is effective in limiting the replication of SARS-CoV-2 in cell culture and thus possibly could offer double benefits as diabetic COVID-19 patients by lowering both blood glucose levels and viral load.

Metformin is associated with reduced COVID-19 severity in patients with prediabetes

AIMS

Studies suggest that metformin is associated with reduced COVID-19 severity in individuals with diabetes compared to other antihyperglycemics. We assessed if metformin is associated with reduced incidence of severe COVID-19 for patients with prediabetes or polycystic ovary syndrome (PCOS), common diseases that increase the risk of severe COVID-19.

METHODS

This observational, retrospective study utilized EHR data from 52 hospitals for COVID-19 patients with PCOS or prediabetes treated with metformin or levothyroxine/ondansetron (controls). After balancing via inverse probability score weighting, associations with COVID-19 severity were assessed by logistic regression.

RESULTS

In the prediabetes cohort, when compared to levothyroxine, metformin was associated with a significantly lower incidence of COVID-19 with "mild-ED" or worse (OR [95% CI]: 0.636, [0.455-0.888]) and "moderate" or worse severity (0.493 [0.339-0.718]). Compared to ondansetron, metformin was associated with lower incidence of "mild-ED" or worse severity (0.039 [0.026-0.057]), "moderate" or worse (0.045 [0.03-0.069]), "severe" or worse (0.183 [0.077-0.431]), and "mortality/hospice" (0.223 [0.071-0.694]). For PCOS, metformin showed no significant differences in severity compared to levothyroxine, but was associated with a significantly lower incidence of "mild-ED" or worse (0.101 [0.061-0.166]), and "moderate" or worse (0.094 [0.049-0.18]) COVID-19 outcome compared to ondansetron.

CONCLUSIONS

Metformin use is associated with less severe COVID-19 in patients with prediabetes or PCOS.

Metformin: Activation of 5′ AMP-activated protein kinase and its emerging potential beyond anti-hyperglycemic action

Metformin is a plant-based drug belonging to the class of biguanides and is known to treat type-2 diabetes mellitus (T2DM). The drug, combined with controlling blood glucose levels, improves the body’s response to insulin. In addition, trials have identified the cardioprotective potential of metformin in the diabetic population receiving the drug. Activation of 5′ AMP-activated protein kinase (AMPK) is the major pathway for these potential beneficial effects of metformin. Historically, much emphasis has been placed on the potential indications of metformin beyond its anti-diabetic use. This review aims to appraise other potential uses of metformin primarily mediated by the activation of AMPK. We also discuss various mechanisms, other than AMPK activation, by which metformin could produce beneficial effects for different conditions. Databases including PubMed/MEDLINE and Embase were searched for literature relevant to the review’s objective. Reports from both research and review articles were considered. We found that metformin has diverse effects on the human body systems. It has been shown to exert anti-inflammatory, antioxidant, cardioprotective, metabolic, neuroprotective, anti-cancer, and antimicrobial effects and has now even been identified as effective against SARS-CoV-2. Above all, the AMPK pathway has been recognized as responsible for metformin’s efficiency and effectiveness. Owing to its extensive potential, it has the capability to become a part of treatment regimens for diseases apart from T2DM.

Free, Conjugated, and Bound Phenolics in Peel and Pulp from Four Wampee Varieties: Relationship between Phenolic Composition and Bio-Activities by Multivariate Analysis

Free, conjugated, and bound phenolic fractions of peel and pulp in four wampee varieties from South China were analyzed for their contents, composition, antioxidant capacities, and inhibitory activities against α-glucosidase. We found that there were significant differences in phenolic/flavonoid contents among diverse varieties and different parts (peel and pulp), and the contents were highest in the peel’s bound form. The results of UHPL-Q-Exactive HF-X and HPLC showed that chlorogenic acid, gentisic acid, and rutin were abundantly distributed over the three phenolic fractions in peel and pulp of all wampee samples, while isoquercitrin was the most abundant in the conjugated form of peel/pulp and myricetin had the richest content in the free form of peel/pulp. Wampee peel had stronger antioxidant capacities of ABTS+, DPPH, ·OH, and FRAP than the pulp, and the bound phenolic fraction of the peel/pulp had much higher antioxidant activities than FP and CP fractions. It is interesting that the same phenolic fraction of the wampee peel displayed roughly close IC₅₀ values of α-glucosidase inhibition to those from the pulp samples. The relationship between individual phenolic and TPC/TFC/the bio-activities and the similarity among the free, conjugated, and bound phenolic fractions in peel and pulp samples were explored by using Pearson correlation analysis, principal component analysis, and hierarchical cluster analysis. This work provides a systematic and comprehensive comparison of the three phenolic fractions of diverse wampee varieties and different parts, and a rationale for applying phenolics from wampee fruits.

Immunomodulatory Factor TIM3 of Cytolytic Active Genes Affected the Survival and Prognosis of Lung Adenocarcinoma Patients by Multi-Omics Analysis

[Objective] Using multi-omics research methods to explore cytolytic activity-related genes through the immunoregulatory factors HAVCR2 (TIM3) affecting the survival and prognosis of lung adenocarcinoma. [Methods] We combined Cox single factor regression and lasso regression feature selection algorithm to screen out the key genes of cytolytic activity in lung adenocarcinoma, and applied multi-omics research to explore the clinical predictive value of the model, including onset risk, independent prognosis, clinical relevance, signal transduction pathways, drug sensitivity, and the correlation of immune regulatory factors, etc. TCGA data are used as the experimental group, and GEO data is used as the external data control group to verify the stability of the model. The survival curve was generated by the Kaplan–Meier method and compared by log-rank, and the Cox proportional hazard model was used for multivariate analysis. In this study, 10 fresh tissue samples of lung adenocarcinoma were collected for cellular immunohistochemical experiments to analyze the expression of immunoregulatory factors in cancer tissues, and the key immunoregulatory factors were verified and screened out. [Results] A total of 450 genes related to cytolytic activity were differentially expressed, of which 273 genes were up-regulated and 177 genes were down-regulated. A total of 91 key genes related to cytolytic activity related to the prognosis of lung adenocarcinoma were screened through Cox single factor regression. The ROC curve results showed that the AUC values of 1, 3, and 5 years in the training set and test set were all greater than 0.7, indicating that the model has a valid verification. The level of risk score is significantly related to the sensitivity of patients to AKT inhibitor VIII, Lenalidomide, and Tipifarnib. In addition, our study also found that receptor and MHC genes related to immunomodulatory, and chemokines, including HAVCR2, are more highly expressed in the low-risk group. [Conclusions] HAVCR2 (TIM3) immunoregulatory factors affect the expression of key genes that affect cytolytic activity in lung adenocarcinoma cells, and to some extent indirectly affect the survival and prognosis of patients with lung adenocarcinoma.

Effects of metformin on changes of miR-19a and miR-221 expression associated with myocardial infarction in patients with type 2 diabetes

BACKGROUND

The presence of hyperglycemia is a risk factor for cardiovascular diseases, as it increases the risk of myocardial infarction (MI). Metformin is considered an effective anti-hyperglycemic drug for patients with type 2 diabetes. Prediction of microRNAs is valuable in determining the risk of MI.

AIM

This study aimed to measure the expression of two microRNAs, which are involved in the risk of MI and vascular stenosis among metformin users and non-users with MI.

METHODS

In this study, we analyzed the expression of two microRNAs, collected from the blood samples of 180 subjects with MI, using the quantitative polymerase chain reaction (qPCR) assay. The subjects were categorized into three groups: non-diabetic patients with MI (MIND), diabetic patients with MI not using metformin (MIDMet-), and diabetic patients with MI using metformin (MIDMet+). To assess the sensitivity and specificity of miR-19a and miR-221 expression as potential biomarkers for MI, the receiver operating characteristic curve (ROC) analysis was conducted for both diabetic groups.

RESULTS

The diabetic MIDMet + group exhibited a significant decrease in the expression levels of miR-221 (7.2 folds) and miR-19a (5.3 folds) as compared to the MIDMet- and MIND groups (p < 0.05). The ROC analysis revealed that the areas under the ROC curve (AUC) for circulating miR-19a and miR-221 were 0.931 and 0.965 in patients with type 2 diabetes, respectively (p < 0.001).

CONCLUSION

Based on the present findings, metformin therapy can influence cardiovascular disorders and their outcomes through down-regulation of microRNAs. Also, exploration of microRNAs and the effects of metformin on their reduction can provide a potential therapeutic strategy for patients with type 2 diabetes by reducing the MI risk.

Metformin is Associated with Reduced COVID-19 Severity in Patients with Prediabetes

Background

With the continuing COVID-19 pandemic, identifying medications that improve COVID-19 outcomes is crucial. Studies suggest that use of metformin, an oral antihyperglycemic, is associated with reduced COVID-19 severity in individuals with diabetes compared to other antihyperglycemic medications. Some patients without diabetes, including those with polycystic ovary syndrome (PCOS) and prediabetes, are prescribed metformin for off-label use, which provides an opportunity to further investigate the effect of metformin on COVID-19.

Participants

In this observational, retrospective analysis, we leveraged the harmonized electronic health record data from 53 hospitals to construct cohorts of COVID-19 positive, metformin users without diabetes and propensity-weighted control users of levothyroxine (a medication for hypothyroidism that is not known to affect COVID-19 outcome) who had either PCOS (n = 282) or prediabetes (n = 3136). The primary outcome of interest was COVID-19 severity, which was classified as: mild, mild ED (emergency department), moderate, severe, or mortality/hospice.

Results

In the prediabetes cohort, metformin use was associated with a lower rate of COVID-19 with severity of mild ED or worse (OR: 0.630, 95% CI 0.450 - 0.882, p < 0.05) and a lower rate of COVID-19 with severity of moderate or worse (OR: 0.490, 95% CI 0.336 - 0.715, p < 0.001). In patients with PCOS, we found no significant association between metformin use and COVID-19 severity, although the number of patients was relatively small.

Conclusions

Metformin was associated with less severe COVID-19 in patients with prediabetes, as seen in previous studies of patients with diabetes. This is an important finding, since prediabetes affects between 19 and 38% of the US population, and COVID-19 is an ongoing public health emergency. Further observational and prospective studies will clarify the relationship between metformin and COVID-19 severity in patients with prediabetes, and whether metformin usage may reduce COVID-19 severity.

Cell deaths: Involvement in the pathogenesis and intervention therapy of COVID-19

The current pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has dramatically influenced various aspects of the world. It is urgent to thoroughly study pathology and underlying mechanisms for developing effective strategies to prevent and treat this threatening disease. It is universally acknowledged that cell death and cell autophagy are essential and crucial to maintaining host homeostasis and participating in disease pathogenesis. At present, more than twenty different types of cell death have been discovered, some parts of which have been fully understood, whereas some of which need more investigation. Increasing studies have indicated that cell death and cell autophagy caused by coronavirus might play an important role in virus infection and pathogenicity. However, the knowledge of the interactions and related mechanisms of SARS-CoV-2 between cell death and cell autophagy lacks systematic elucidation. Therefore, in this review, we comprehensively delineate how SARS-CoV-2 manipulates diverse cell death (including apoptosis, necroptosis, pyroptosis, ferroptosis, and NETosis) and cell autophagy for itself benefits, which is simultaneously involved in the occurrence and progression of COVID-19, aiming to provide a reasonable basis for the existing interventions and further development of novel therapies.

Metformin Regulates Alveolar Macrophage Polarization to Protect Against Acute Lung Injury in Rats Caused by Paraquat Poisoning

This study explored the role of metformin (MET) in regulating the polarization of alveolar macrophages to protect against acute lung injury (ALI) in rats caused by paraquat (PQ) poisoning. The in vivo studies showed that the 35 mg/kg dose of MET increased the survival rate of rats, alleviated pathological damages to the lungs and their systemic inflammation, promoted the reduction of the pro-inflammatory factors interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels, and increased the anti-inflammatory factor IL-10 levels in the rat serum. At the same time, the MET intervention decreased the expression of M1 macrophage marker iNOS in the lungs of the PQ-poisoned rats while increasing the M2 macrophage marker, Arg1, expression. In vitro, the concentration of MET > 10 mmol/L affected NR8383 viability adversely and was concentration-dependent; however, no adverse impact on NR8383 viability was observed at MET ≤ 10 mmol/L concentration, resisting the reducing effect of PQ on NR8383 vitality. The PQ-induced NR8383 model with MET intervention showed significantly reduced secretions of IL-6 and TNF-α in NR8383, and lowered expressions of M1 macrophage markers iNOS and CD86. Additionally, MET increased IL-10 secretion and the M2 macrophage markers, Arg1 and Mrcl, expressions. Therefore, we speculate that MET could regulate alveolar macrophage polarization to protect against PQ-poisoning caused ALI.

NETosis and Neutrophil Extracellular Traps in COVID-19: Immunothrombosis and Beyond

Infection with SARS-CoV-2, the causative agent of the Coronavirus disease 2019 (COVID-19) pandemic, causes respiratory problems and multifaceted organ dysfunction. A crucial mechanism of COVID-19 immunopathy is the recruitment and activation of neutrophils at the infection site, which also predicts disease severity and poor outcomes. The release of neutrophil extracellular traps (NETs), occurring during a regulated form of neutrophil cell death known as NETosis, is a key effector function that mediates harmful effects caused by neutrophils. Abundant NETosis and NET generation have been observed in the neutrophils of many COVID-19 patients, leading to unfavorable coagulopathy and immunothrombosis. Moreover, excessive NETosis and NET generation are now more widely recognized as mediators of additional pathophysiological abnormalities following SARS-CoV-2 infection. In this minireview, we introduce subtypes of NET-producing neutrophils (e.g., low-density granulocytes) and explain the biological importance of NETs and the protein cargos of NETs in COVID-19. In addition, we discuss the mechanisms by which SARS-CoV-2 causes NETosis by upregulating viral processes (e.g., viral entry and replication) as well as host pro-NET mechanisms (e.g., proinflammatory mediator release, platelet activation, and autoantibody production). Furthermore, we provide an update of the main findings of NETosis and NETs in immunothrombosis and other COVID-19-related disorders, such as aberrant immunity, neurological disorders, and post COVID-19 syndromes including lung fibrosis, neurological disorder, tumor progression, and deteriorated chronic illness. Finally, we address potential prospective COVID-19 treatment strategies that target dysregulated NETosis and NET formation via inhibition of NETosis and promotion of NET degradation, respectively.

Modulation of Macrophage Immunometabolism: A New Approach to Fight Infections

Macrophages are essential innate immune cells that contribute to host defense during infection. An important feature of macrophages is their ability to respond to extracellular cues and to adopt different phenotypes and functions in response to these stimuli. The evidence accumulated in the last decade has highlighted the crucial role of metabolic reprogramming during macrophage activation in infectious context. Thus, understanding and manipulation of macrophage immunometabolism during infection could be of interest to develop therapeutic strategies. In this review, we focus on 5 major metabolic pathways including glycolysis, pentose phosphate pathway, fatty acid oxidation and synthesis, tricarboxylic acid cycle and amino acid metabolism and discuss how they sustain and regulate macrophage immune function in response to parasitic, bacterial and viral infections as well as trained immunity. At the end, we assess whether some drugs including those used in clinic and in development can target macrophage immunometabolism for potential therapy during infection with an emphasis on SARS-CoV2 infection.

Effect of early treatment with metformin on risk of emergency care and hospitalization among patients with COVID-19: The TOGETHER randomized platform clinical trial

Background

Observational studies have postulated a therapeutic role of metformin in treating COVID-19. We conducted an adaptive platform clinical trial to determine whether metformin is an effective treatment for high-risk patients with early COVID-19 in an outpatient setting.

Methods

The TOGETHER Trial is a placebo-controled, randomized, platform clinical trial conducted in Brazil. Eligible participants were symptomatic adults with a positive antigen test for SARS-CoV-2. We enroled eligible patients over the age of 50 years or with a known risk factor for disease severity. Patients were randomly assigned to receive either placebo or metformin (750 mg twice daily for 10 days or placebo, twice daily for 10 days). The primary outcome was hospitalization defined as either retention in a COVID-19 emergency setting for > 6 h or transfer to tertiary hospital due to COVID-19 at 28 days post randomization. Secondary outcomes included viral clearance at day 7, time to hospitalization, mortality, and adverse drug reactions. We used a Bayesian framework to determine probability of success of the intervention compared to placebo.

Findings

The TOGETHER Trial was initiated June 2, 2020. We randomized patients to metformin starting January 15, 2021. On April 3, 2021, the Data and Safety Monitoring Committee recommended stopping enrollment into the metformin arm due to futility. We recruited 418 participants, 215 were randomized to the metformin arm and 203 to the placebo arm. More than half of participants (56.0%) were over the age of 50 years and 57.2% were female. Median age was 52 years. The proportion of patients with the primary outcome at 28 days was not different between the metformin and placebo group (relative risk [RR] 1.14[95% Credible Interval 0.73; 1.81]), probability of superiority 0.28. We found no significant differences between the metformin and placebo group on viral clearance through to day 7 (Odds ratio [OR], 0.99, 95% Confidence Intervals 0.88–1.11) or other secondary outcomes.

Interpretation

In this randomized trial, metformin did not provide any clinical benefit to ambulatory patients with COVID-19 compared to placebo, with respect to reducing the need for retention in an emergency setting or hospitalization due to worsening COVID-19. There were also no differences between metformin and placebo observed for other secondary clinical outcomes.

Funding

The trial was supported by FastGrants and The Rainwater Foundation.

Future Directions for the Discovery of Natural Product-Derived Immunomodulating Drugs

Drug discovery from natural sources is going through a renaissance, having spent many decades in the shadow of synthetic molecule drug discovery, despite the fact that natural product-derived compounds occupy a much greater chemical space than those created through synthetic chemistry methods. With this new era comes new possibilities, not least the novel targets that have emerged in recent times and the development of state-of-the-art technologies that can be applied to drug discovery from natural sources. Although progress has been made with some immunomodulating drugs, there remains a pressing need for new agents that can be used to treat the wide variety of conditions that arise from disruption, or over-activation, of the immune system; natural products may therefore be key in filling this gap. Recognising that, at present, there is no authoritative article that details the current state-of-the-art of the immunomodulatory activity of natural products, this in-depth review has arisen from a joint effort between the International Union of Basic and Clinical Pharmacology (IUPHAR) Natural Products and Immunopharmacology, with contributions from a Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation number of world-leading researchers in the field of natural product drug discovery, to provide a "position statement" on what natural products has to offer in the search for new immunomodulatory argents. To this end, we provide a historical look at previous discoveries of naturally occurring immunomodulators, present a picture of the current status of the field and provide insight into the future opportunities and challenges for the discovery of new drugs to treat immune-related diseases.

The Petasites hybridus CO2 Extract (Ze 339) Blocks SARS-CoV-2 Replication In Vitro

The coronavirus disease 2019 (COVID-19), caused by a novel coronavirus (SARS-CoV-2), has spread worldwide, affecting over 250 million people and resulting in over five million deaths. Antivirals that are effective are still limited. The antiviral activities of the Petasites hybdridus CO₂ extract Ze 339 were previously reported. Thus, to assess the anti-SARS-CoV-2 activity of Ze 339 as well as isopetasin and neopetasin as major active compounds, a CPE and plaque reduction assay in Vero E6 cells was used for viral output. Antiviral effects were tested using the original virus (Wuhan) and the Delta variant of SARS-CoV-2. The antiviral drug remdesivir was used as control. Pre-treatment with Ze 339 in SARS-CoV-2-infected Vero E6 cells with either virus variant significantly inhibited virus replication with IC₅₀ values of 0.10 and 0.40 μg/mL, respectively. The IC₅₀ values obtained for isopetasin ranged between 0.37 and 0.88 μM for both virus variants, and that of remdesivir ranged between 1.53 and 2.37 μM. In conclusion, Ze 339 as well as the petasins potently inhibited SARS-CoV-2 replication in vitro of the Wuhan and Delta variants. Since time is of essence in finding effective treatments, clinical studies will have to demonstrate if Ze339 can become a therapeutic option to treat SARS-CoV-2 infections.

Free fatty acids-induced neutrophil extracellular traps lead to dendritic cells activation and T cell differentiation in acute lung injury

This study aimed to investigate whether free fatty acids (FFAs) could induce the release of neutrophil extracellular traps (NETs), as well as the mechanism of FFAs-induced NETs in acute lung injury (ALI). FFAs were used to induce NETs production. The reactive oxygen species (ROS) production was detected after FFA and NADPH oxidase inhibitor treatments. The association between FFAs-induced NETs and the activation of p38, ERK, and JNK pathways was investigated. The effect of FFAs-induced NETs on the dendritic cells (DCs) activation and T cell differentiation was investigated. FFAs could induce neutrophils to produce NETs. FFAs significantly promoted ROS production and increased the expression of ERK, p38 and JNK, and treatment of the inhibitors of NAPDH oxidase (DPI), p38 (SB202190), ERK1/2 (U0126) and JNK (SP600125) inhibited FAAs-induced NETs production. FFAs induced NETs could promote DCs activation and consequently led to the differentiation of primary CD4+ T cells into Th1 and Th17 cells and the release of IL-1β, IL-12 and TNF-α. FFAs are capable of inducing NETs via NOX, ERK, p38 and JNK pathways. FFA-induced NETs further lead to DCs activation and T cell differentiation, which can well explain the mechanism of ALI caused by FFAs.

The effect of metformin on body mass index and metabolic parameters in non-diabetic HIV-positive patients: a meta-analysis

We sought to evaluate the effetc of metformin on body mass index (BMI) and metabolic parameters in HIV-positive patients. We performed a comprehensive search through five major indexing databases, using keywords ("metformin" OR "dimethylguanylguanidine" OR "biguanide" OR "Glucophage") AND ("HIV" OR "human immunodeficiency virus" OR "AIDS" OR "Acquired immunodeficiency syndrome"), and all possible combinations until January 15, 2021. We measured standardized mean differences (SMD) and 95% confidence intervals (CI) for each outcome. We finally included 12 RCTs (577 participants, 274 in the metformin group and 303 in the comparators). Metformin did not significantly change BMI index compared to various comparators. Metformin generally improve LDL levels (SMD = 0.29, 95% CI: - 1.00 1.57, P = 0.01), HDL levels (SMD = - 0.15, 95% CI: - 0.72 0.41, P = 0.001), triglycerides values (SMD = 0.46, 95% CI: - 0.36 1.27, P < 0.00001), fasting glucose (SMD = - 0.82, 95% CI: - 1.80 0.15, P < 0.00001), insulin 120 min (SMD = - 0.82, 95% CI: - 1.59-0.04, P = 0.02), and glucose 120 min (SMD = - 1.24, 95% CI: - 2.57 0.10, P < 0.0001), but worsened total cholesterol values (SMD = 1.24, 95% CI: - 0.98 3.46, P = 0.0001). Metformin is safe for weight loss in obese people; however, this drug may not be suitable for everyone, especially those who are not overweight. Nevertheless the body of evidences may suggest that metformin had promising impacts on metabolic parameters in patients with both HIV, it is still unknown that such surrogate changes will translate to long-standing clinical advantages.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00869-1.

Managing diabetes in diabetic patients with COVID: where do we start from?

AIMS

COVID-19 has and still is sweeping away the national health systems worldwide. In this review, we sought to determine the evidence base proofs on the antidiabetic treatment capable to reduce the risk of COVID-19-related mortality.

METHODS

We have performed a systematic search of published articles using PubMed, and EMBASE from March 2020 to March 31st, 2021. We excluded editorials, commentary, letters to the editor, reviews, and studies that did not have mortality as an outcome. For metformin and insulin only, we performed a meta-analysis using Cochrane RevMan 5.2.

RESULTS

Among antidiabetic drugs, metformin was the only drug associated with a reduced risk of mortality. Conversely, insulin appears associated with an increased risk. The other classes of drugs were neutral.

CONCLUSIONS

The totality of articles reports retrospective data strongly affected by "channeling bias" so that most of the existing results on each class of drugs are driven by the phenotype of patients likely to receive that specific drug by prescription.

Adverse Effects of Metformin From Diabetes to COVID-19, Cancer, Neurodegenerative Diseases, and Aging: Is VDAC1 a Common Target?

Metformin has been used for treating diabetes mellitus since the late 1950s. In addition to its antihyperglycemic activity, it was shown to be a potential drug candidate for treating a range of other diseases that include various cancers, cardiovascular diseases, diabetic kidney disease, neurodegenerative diseases, renal diseases, obesity, inflammation, COVID-19 in diabetic patients, and aging. In this review, we focus on the important aspects of mitochondrial dysfunction in energy metabolism and cell death with their gatekeeper VDAC1 (voltage-dependent anion channel 1) as a possible metformin target, and summarize metformin’s effects in several diseases and gut microbiota. We question how the same drug can act on diseases with opposite characteristics, such as increasing apoptotic cell death in cancer, while inhibiting it in neurodegenerative diseases. Interestingly, metformin’s adverse effects in many diseases all show VDAC1 involvement, suggesting that it is a common factor in metformin-affecting diseases. The findings that metformin has an opposite effect on various diseases are consistent with the fact that VDAC1 controls cell life and death, supporting the idea that it is a target for metformin.

Preliminary Evidence for IL-10-Induced ACE2 mRNA Expression in Lung-Derived and Endothelial Cells: Implications for SARS-Cov-2 ARDS Pathogenesis

Angiotensin-converting enzyme 2 (ACE2) is a receptor for the spike protein of SARS-COV-2 that allows viral binding and entry and is expressed on the surface of several pulmonary and non-pulmonary cell types, with induction of a “cytokine storm” upon binding. Other cell types present the receptor and can be infected, including cardiac, renal, intestinal, and endothelial cells. High ACE2 levels protect from inflammation. Despite the relevance of ACE2 levels in COVID-19 pathogenesis, experimental studies to comprehensively address the question of ACE2 regulations are still limited. A relevant observation from the clinic is that, besides the pro-inflammatory cytokines, such as IL-6 and IL-1β, the anti-inflammatory cytokine IL-10 is also elevated in worse prognosis patients. This could represent somehow a “danger signal”, an alarmin from the host organism, given the immuno-regulatory properties of the cytokine. Here, we investigated whether IL-10 could increase ACE2 expression in the lung-derived Calu-3 cell line. We provided preliminary evidence of ACE2 mRNA increase in cells of lung origin in vitro, following IL-10 treatment. Endothelial cell infection by SARS-COV-2 is associated with vasculitis, thromboembolism, and disseminated intravascular coagulation. We confirmed ACE2 expression enhancement by IL-10 treatment also on endothelial cells. The sartans (olmesartan and losartan) showed non-statistically significant ACE2 modulation in Calu-3 and endothelial cells, as compared to untreated control cells. We observed that the antidiabetic biguanide metformin, a putative anti-inflammatory agent, also upregulates ACE2 expression in Calu-3 and endothelial cells. We hypothesized that IL-10 could be a danger signal, and its elevation could possibly represent a feedback mechanism fighting inflammation. Although further confirmatory studies are required, inducing IL-10 upregulation could be clinically relevant in COVID-19-associated acute respiratory distress syndrome (ARDS) and vasculitis, by reinforcing ACE2 levels.

Amelioration of polycystic ovary syndrome-related disorders by supplementation of thymoquinone and metformin

Background

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders of reproductive age women with a prevalence of 4-12%. The study aimed to investigate the potential benefit of adding thymoquinone to metformin in alleviating symptoms of polycystic ovarian syndrome. Two hundred seven overweight and obese PCOS patients were divided into two groups. Patients in group A received metformin 500 mg three times daily for 6 months. Patients in group B received a combination of metformin 500 mg and thymoquinone in the form of black cumin oil 500 mg capsules three times daily for 6 months. Follow-up was done after 3 and 6 months from the beginning of the study for evaluation of menstrual cycle pattern, body mass index, waist circumference, hip circumference, and waist:hip ratio, oral glucose tolerance test, glycosylated hemoglobin A1C, superoxide dismutase activity, and malondialdehyde concentration.

Results

Patients who received a combination of black cumin oil capsules and metformin, showed a significant decrease in number of patients suffering from amenorrhea or oligomenorrhea (P = 0.031), significant (P = 0.00) weight reduction (reduced BMI), and body fat redistribution (reduced W/H ratio), regaining oxidative balance with significant increase of SOD activity (P = 0.00) and decrease of MDA concentrations (P = 0.03). Regarding the number of prediabetic patients, there was no statistically significant difference (P = 0.89) when both groups were compared at the end of study period.

Conclusions

Black cumin oil supplementation constitutes a beneficial added value to metformin in ameliorating PCOS-related disorders with resumption of menstrual regularity, weight reduction, change of body fat distribution, and regaining oxidative balance.

Interactions Between Specific Immune Status of Pregnant Women and SARS-CoV-2 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen responsible for the Coronavirus Disease 2019 (COVID-19) global pandemic. Because it is a new and highly contagious coronavirus, most people, especially pregnant women, lack immunity. It is therefore important to understand the interaction between why pregnant women are susceptible to SARS-CoV-2 and the specific immune systems of pregnant women. Here, we provide an overview of the changes that occur in the immune system during pregnancy, the activation and response of the immune system in pregnant women with COVID-19, adverse pregnancy outcomes in pregnant women with COVID-19, and the treatment and prevention of COVID-19 in this population.

Is there a need to reconsider the use of metformin in COVID-19 patients with type 2 diabetes mellitus?

INTRODUCTION

Diabetes has been linked with poorer outcomes in coronavirus disease (COVID-19) patients. However, the question to whether continue or withdraw metformin therapy in COVID-19 patients with type 2 diabetes mellitus remains contentious. This study aims to investigate the association between metformin and poor COVID-19 outcomes.

METHODS

Eligible studies published up to 21 October 2020 were included and appraised for validity, importance, and applicability. The included studies were further ranked according to the level of evidence (LOE).

RESULTS

Nine studies were included for further assessments, of which seven studies stated that metformin was not associated with poor COVID-19 outcomes (LOE II-V), while the other two with poorer designs stated otherwise (LOE V). Although metformin may increase the risk of developing acidosis and lactic acidosis (LOE IV), the observed risks were more accentuated in patients with severe COVID-19 disease or kidney impairment and in patients with > 2 daily metformin doses. Interestingly, one study revealed that metformin may even yield therapeutic role in reducing the risk of COVID-19 mortality (LOE II), although further studies are required to confirm these findings.

CONCLUSIONS

Our findings indicated that metformin may be safely continued in COVID-19 patients. The benefit of metformin therapy with simultaneous continuous monitoring of COVID-19 severity and kidney function may outweigh the risks of lactic acidosis, of which incidence is relatively rare.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13410-021-00924-w.

Multifaceted Role of AMPK in Viral Infections

Viral pathogens often exploit host cell regulatory and signaling pathways to ensure an optimal environment for growth and survival. Several studies have suggested that 5'-adenosine monophosphate-activated protein kinase (AMPK), an intracellular serine/threonine kinase, plays a significant role in the modulation of infection. Traditionally, AMPK is a key energy regulator of cell growth and proliferation, host autophagy, stress responses, metabolic reprogramming, mitochondrial homeostasis, fatty acid β-oxidation and host immune function. In this review, we highlight the modulation of host AMPK by various viruses under physiological conditions. These intracellular pathogens trigger metabolic changes altering AMPK signaling activity that then facilitates or inhibits viral replication. Considering the COVID-19 pandemic, understanding the regulation of AMPK signaling following infection can shed light on the development of more effective therapeutic strategies against viral infectious diseases.

Therapeutic approaches for SARS-CoV-2 infection

Therapeutic approaches to COVID-19 treatment require appropriate inhibitors to target crucial proteins of SARS-CoV-2 replication machinery. It’s been approximately 12 months since the pandemic started, yet no known specific drugs are available. However, research progresses with time in terms of high throughput virtual screening (HTVS) and rational design of repurposed, novel synthetic and natural products discovery by understanding the viral life cycle, immuno-pathological and clinical outcomes in patients based on host’s nutritional, metabolic, and lifestyle status. Further, complementary and alternative medicine (CAM) approaches have also improved resiliency and immune responses. In this article, we summarize all the therapeutic antiviral strategies for COVID-19 drug discovery including computer aided virtual screening, repurposed drugs, immunomodulators, vaccines, plasma therapy, various adjunct therapies, and phage technology to unravel insightful mechanistic pathways of targeting SARS-CoV-2 and host’s intrinsic, innate immunity at multiple checkpoints that aid in the containment of the disease.

Nanotechnology to the Rescue: Treatment Perspective for the Immune Dysregulation Observed in COVID-19

The study of the use of nanotechnology for drug delivery has been extensive. Nanomedical approaches for therapeutics; drug delivery in particular is superior to conventional methods in that it allows for controlled targeted delivery and release, higher stability, extended circulation time, minimal side-effects, and improved pharmacokinetic clearance (of the drug) form the body, to name a few. The magnitude of COVID-19, the current ongoing pandemic has been severe; it has caused widespread the loss of human life. In individuals with severe COVID-19, immune dysregulation and a rampant state of hyperinflammation is observed. This kind of an immunopathological response is detrimental and results in rapid disease progression, development of secondary infections, sepsis and can be fatal. Several studies have pin-pointed the reason for this immune dysregulation; deviations in the signaling pathways involved in the mediation and control of immune responses. In severe COVID-19 patients, many signaling cascades including JAK/STAT, NF-κB, MAPK/ERK, TGF beta, VEGF, and Notch signaling were found to be either upregulated or inactivated. Targeting these aberrant signaling pathways in conjunction with antiviral therapy will effectuate mitigation of the hyperinflammation, hypercytokinemia, and promote faster recovery. The science of the use of nanocarriers as delivery agents to modulate these signaling pathways is not new; it has already been explored for other inflammatory diseases and in particular, cancer therapy. Numerous studies have evaluated the efficacy and potential of nanomedical approaches to modulate these signaling pathways and have been met with positive results. A treatment regime, that includes nanotherapeutics and antiviral therapies will prove effective and holds great promise for the successful treatment of COVID-19. In this article, we review different nanomedical approaches already studied for targeting aberrant signaling pathways, the host immune response to SARS-CoV-2, immunopathology and the dysregulated signaling pathways observed in severe COVID-19 and the current treatment methods in use for targeting signaling cascades in COVID-19. We then conclude by suggesting that the use of nanomedical drug delivery systems for targeting signaling pathways can be extended to effectively target the aberrant signaling pathways in COVID-19 for best treatment results.

Therapeutic Potential of Metformin in COVID-19: Reasoning for Its Protective Role

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections present with increased disease severity and poor clinical outcomes in diabetic patients compared with their nondiabetic counterparts. Diabetes/hyperglycemia-triggered endothelial dysfunction and hyperactive inflammatory and immune responses are correlated to twofold to threefold higher intensive care hospitalizations and more than twice the mortality among diabetic coronavirus disease 2019 (COVID-19) patients. While comorbidities such as obesity, cardiovascular disease, and hypertension worsen the prognosis of diabetic COVID-19 patients, COVID-19 infections are also associated with new-onset diabetes, severe metabolic complications, and increased thrombotic events in the backdrop of aberrant endothelial function. While several antidiabetic medications are used to manage blood glucose levels, we discuss the multifaceted ability of metformin to control blood glucose levels and possibly attenuate endothelial dysfunction, inhibit viral entry and infection, and modify inflammatory and immune responses during SARS-CoV-2 infections. These actions make metformin a viable candidate drug to be considered for repurposing and gaining ground against the SARS-CoV-2-induced tsunami in diabetic COVID-19 patients.

Significance of NETs Formation in COVID-19

Severe contagious respiratory disease—COVID-19—caused by the SARS-CoV-2 coronavirus, can lead to fatal respiratory failure associated with an excessive inflammatory response. Infiltration and spread of SARS-CoV-2 are based on the interaction between the virus’ structural protein S and the cell’s receptor–angiotensin-converting enzyme 2 (ACE2), with the simultaneous involvement of human trans-membrane protease, serine 2 (TMPRSS2). Many scientific reports stress the importance of elevated recruitment and activity of neutrophils, which can form extracellular neutrophil traps (NETs) playing a significant role in the mechanism of combating pathogens, in the pathogenesis of COVID-19. Excessive generation of NETs during prolonged periods of inflammation predisposes for the occurrence of undesirable reactions including thromboembolic complications and damage to surrounding tissues and organs. Within the present manuscript, we draw attention to the impact of NET generation on the severe course of COVID-19 in patients with concurrent cardiovascular and metabolic diseases. Additionally, we indicate the necessity to explore not only the cellular but also the molecular bases of COVID-19 pathogenesis, which may aid the development of dedicated therapies meant to improve chances for the successful treatment of patients. We also present new directions of research into medications that display NETs formation regulatory properties as potential significant therapeutic strategies in the progress of COVID-19.

COVID-19 and Risk of Acute Ischemic Stroke and Acute Lung Injury in Patients With Type II Diabetes Mellitus: The Anti-inflammatory Role of Metformin

Background: Coronavirus disease 19 (COVID-19) is regarded as an independent risk factor for acute ischemic stroke (AIS) due to the induction of endothelial dysfunction, coagulopathy, cytokine storm, and plaque instability. Method: In this retrospective cohort study, a total of 42 COVID-19 patients with type 2 diabetes mellitus (T2DM) who presented with AIS within 1 week of displaying COVID-19 symptoms were recruited. According to the current anti-DM pharmacotherapy, patients were divided into two groups: a Metformin group of T2DM patients with COVID-19 and AIS on metformin therapy (850 mg, 3 times daily (n = 22), and a Non-metformin group of T2DM patients with COVID-19 and AIS under another anti-DM pharmacotherapy like glibenclamide and pioglitazone (n = 20). Anthropometric, biochemical, and radiological data were evaluated. Results: Ferritin serum level was lower in metformin-treated patients compared to non-metformin treated patients (365.93 ± 17.41 vs. 475.92 ± 22.78 ng/mL, p = 0.0001). CRP, LDH, and D-dimer serum levels were also lowered in metformin-treated patients compared to non-metformin treated patients (p = 0.0001). In addition, lung CT scan scores of COVID-19 patients was 30.62 ± 10.64 for metformin and 36.31 ± 5.03 for non-metformin treated patients. Conclusion: Metformin therapy in T2DM patients was linked to a lower risk of AIS during COVID-19. Further studies are needed to observe the link between AIS in COVID-19 diabetic patients and metformin therapy.

COVID-19 and Obesity: Epidemiology, Pathogenesis and Treatment

The growing prevalence of overweight and obesity has been a worldwide public health issue. During the COVID-19 pandemic, obesity is associated with a higher risk of severity and a worse clinical outcome of SARS-COV-2 infection. This may be because of the chronic low-grade inflammation, impaired immune response and metabolic disorders in obese patients. In this narrative review, we have summarized the association between obesity and COVID-19 and discussed the potential pathogenesis and treatment in these patients. This work may provide practical suggestions on the clinical management of obese COVID-19 patients.

Macrophage-derived cytokines in pneumonia: Linking cellular immunology and genetics

Macrophages represent the first line of anti-pathogen defense - they encounter invading pathogens to perform the phagocytic activity, to deliver the plethora of pro- and anti-inflammatory cytokines, and to shape the tissue microenvironment. Throughout pneumonia course, alveolar macrophages and infiltrated blood monocytes produce increasing cytokine amounts, which activates the antiviral/antibacterial immunity but can also provoke the risk of the so-called cytokine “storm” and normal tissue damage. Subsequently, the question of how the cytokine spectrum is shaped and balanced in the pneumonia context remains a hot topic in medical immunology, particularly in the COVID19 pandemic era. The diversity in cytokine profiles, involved in pneumonia pathogenesis, is determined by the variations in cytokine-receptor interactions, which may lead to severe cytokine storm and functional decline of particular tissues and organs, for example, cardiovascular and respiratory systems. Cytokines and their receptors form unique profiles in individual patients, depending on the (a) microenvironmental context (comorbidities and associated treatment), (b) lung monocyte heterogeneity, and (c) genetic variations. These multidisciplinary strategies can be proactively considered beforehand and during the pneumonia course and potentially allow the new age of personalized immunotherapy.