mTOR inhibition: a double-edged sword in patients with COVID-19?

Cognitive Impairment in Multiple Sclerosis

Almost three million individuals suffer from multiple sclerosis (MS) throughout the world, a demyelinating disease in the nervous system with increased prevalence over the last five decades, and is now being recognized as one significant etiology of cognitive loss and dementia. Presently, disease modifying therapies can limit the rate of relapse and potentially reduce brain volume loss in patients with MS, but unfortunately cannot prevent disease progression or the onset of cognitive disability. Innovative strategies are therefore required to address areas of inflammation, immune cell activation, and cell survival that involve novel pathways of programmed cell death, mammalian forkhead transcription factors (FoxOs), the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), the silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), and associated pathways with the apolipoprotein E (APOE-ε4) gene and severe acute respiratory syndrome coronavirus (SARS-CoV-2). These pathways are intertwined at multiple levels and can involve metabolic oversight with cellular metabolism dependent upon nicotinamide adenine dinucleotide (NAD+). Insight into the mechanisms of these pathways can provide new avenues of discovery for the therapeutic treatment of dementia and loss in cognition that occurs during MS.

Cellular Metabolism: A Fundamental Component of Degeneration in the Nervous System

It is estimated that, at minimum, 500 million individuals suffer from cellular metabolic dysfunction, such as diabetes mellitus (DM), throughout the world. Even more concerning is the knowledge that metabolic disease is intimately tied to neurodegenerative disorders, affecting both the central and peripheral nervous systems as well as leading to dementia, the seventh leading cause of death. New and innovative therapeutic strategies that address cellular metabolism, apoptosis, autophagy, and pyroptosis, the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), growth factor signaling with erythropoietin (EPO), and risk factors such as the apolipoprotein E (APOE-ε4) gene and coronavirus disease 2019 (COVID-19) can offer valuable insights for the clinical care and treatment of neurodegenerative disorders impacted by cellular metabolic disease. Critical insight into and modulation of these complex pathways are required since mTOR signaling pathways, such as AMPK activation, can improve memory retention in Alzheimer's disease (AD) and DM, promote healthy aging, facilitate clearance of β-amyloid (Aß) and tau in the brain, and control inflammation, but also may lead to cognitive loss and long-COVID syndrome through mechanisms that can include oxidative stress, mitochondrial dysfunction, cytokine release, and APOE-ε4 if pathways such as autophagy and other mechanisms of programmed cell death are left unchecked.

Prostaglandins and non-steroidal anti-inflammatory drugs in Covid-19

In response to different viral infections, including SARS-CoV-2 infection, pro-inflammatory, anti-inflammatory cytokines, and bioactive lipids are released from infected and immune cells. One of the most critical bioactive lipids is prostaglandins (PGs) which favor perseverance of inflammation leading to chronic inflammation as PGs act as cytokine amplifiers. PGs trigger the release of pro-inflammatory cytokines, activate Th cells, recruit immune cells, and increase the expression of pro-inflammatory genes. Therefore, PGs may induce acute and chronic inflammations in various inflammatory disorders and viral infections like SARS-CoV-2. PGs are mainly inhibited by non-steroidal anti-inflammatory drugs (NSAIDs) by blocking cyclooxygenase enzymes (COXs), which involve PG synthesis. NSAIDs reduce inflammation by selective or non-selective blocking activity of COX2 or COX1/2, respectively. In the Covid-19 era, there is a tremendous controversy regarding the use of NSAIDs in the management of SARS-CoV-2 infection. As well, the possible role of PGs in the pathogenesis of SARS-CoV-2 infection is not well-defined. Thus, the objective of the present study is to review the potential role of PGs and NSAIDs in Covid-19 in a narrative review regarding the preponderance of assorted views.

An overview of possible pivotal mechanisms of Genistein as a potential phytochemical against SARS-CoV-2 infection: A hypothesis

The Coronavirus Disease 2019 (COVID‐19) pandemic has been caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). It is a global problem that humanity has not yet found a definitive solution for it. In this regard, a global effort has been done to find effective or potential adjuvant therapies in order to fight this infection. Genistein is a small, biologically active phytoestrogen flavonoid that is found in high amounts in soy and plants of the Fabaceae family. This important compound is known due to its anti‐cancer, anti‐inflammatory, and antioxidant effects. Additionally, protective effects of genistein have been reported in different pathological conditions through modulating intracellular pathways such as PI3K, Akt, mTOR, NF‐κB, PPARγ, AMPK, and Nrf2. Scientific evidence suggests that genistein could have a potential role to treat COVID‐19 through its anti‐inflammatory and anti‐oxidant effects. Furthermore, it appears to interfere with intracellular pathways involved in viral entry into the cell. This review provides a basis for further research and development of clinical applications of genistein as a potential alternative therapy to decrease inflammation and oxidative stress in COVID‐19 patients.

Rapamycin golden jubilee and still the miraculous drug: a potent immunosuppressant, antitumor, rejuvenative agent, and potential contributor in COVID-19 treatment

Although celebrating its golden jubilee, rapamycin’s importance keeps increasing by the day. Starting as a promising antifungal agent, then as a potent immunosuppressant, strong anticancer drug, and now rapamycin is attracting serious attention as a rejuvenative agent and a possible contributor in treating this era pandemic, COVID-19. Due to its diverse biological activities and promising medical applications, we aimed in this review to put rapamycin under the spot and highlight its discovery, famous microbial producers, reported biological activities, chemical structure, famous analogues, and biosynthesis. Moreover, discuss some rapamycin production approaches including solid-state fermentation, and stressing out producing strain. On the other hand, describe its action mechanism and trials to use it in treatment of COVID-19. Additionally, we highlighted some of the side effects accompanying its use, and describe some approaches reported to minimize these undesired effects. Finally, we report the current status of rapamycin and its analogues in global market, and discuss future prospects of this potent drug.

mTOR Inhibitor Use Is Associated With a Favorable Outcome of COVID-19 in Patients of Kidney Transplant: Results of a Retrospective Study

Introduction

In solid organ transplant recipients, COVID-19 is associated with a poor prognosis because of immunosuppression. Some studies suggest a potential therapeutic role of mammalian Target of Rapamycin (mTOR) inhibitors in SARS-CoV-2 infection. This study aimed to assess the impact of mTOR employment on the evolution and outcome of SARS-CoV-2 infection in solid organ transplant recipients.

Methods

We enrolled kidney transplant patients attending the Azienda Ospedaliera Universitaria Federico II in Naples and followed up on these patients from March 2020 to June 2021. We evaluated the risk of acquiring the SARS-CoV-2 infection, the clinical presentation of the disease, and its outcome together with the type of immunosuppressive therapy. Finally, we assessed the impact of mTOR inhibitors on relevant clinical metrics of SARS-CoV-2 infection.

Results

We enrolled 371 patients, of whom 56 (15.1%) contracted SARS-CoV-2 infection during the period of the study. There were no differences observed among the different immunosuppressive therapies concerning the risk of acquiring SARS-CoV-2 infection. In contrast, the type of immunosuppressive therapy had a significant impact on the outcome of the disease. In detail, patients who received mTOR inhibitors, as part of their immunosuppressive therapy, compared to other regimens had a lower chance of developing a moderate or severe form of the disease (OR = 0.8, 95, CI: (0.21-0.92), P = 0.041).

Conclusion

In kidney transplant patients, the use of mTOR inhibitors as part of an immunosuppressive regimen is associated with a better prognosis in the case of COVID-19.

Diabetes and COVID-19: The potential role of mTOR

Diabetes is the most frequent comorbidity among patients with COVID-19. COVID-19 patients with diabetes have a more severe prognosis than patients without diabetes. However, the etiopathogenetic mechanisms underlying this more unfavorable outcome in these patients are not clear. Probably the etiopathogenetic mechanisms underlying diabetes could represent a favorable substrate for a greater development of the inflammatory process already dysregulated in COVID-19 with a more severe evolution of the disease. In the attempt to shed light on the possible etiopathogenetic mechanisms, we wanted to evaluate the possible role of mTOR (mammalian Target Of Rapamycin) pathway in this context. We searched the PubMed and Scopus databases to identify articles involving diabetes and the mTOR pathway in COVID-19. The mTOR pathway could be involved in this etiopathogenetic mechanism, in particular, the activation and stimulation of this pathway could favor an inflammatory process that is already dysregulated in itself, while its inhibition could be a way to regulate this dysregulated inflammatory process. However, much remains to be clarified about the mechanisms of the mTOR pathway and its role in COVID-19. The aim of this review is to to understand the etiopathogenesis underlying COVID-19 in diabetic patients and the role of mTOR pathway in order to be able to search for new weapons to deal with this disease.

Case Report of COVID-19 Infection After Kidney Transplant Treated With Casirivimab-Imdevimab and Mycophenolate Mofetil Changed to Everolimus

BACKGROUND

Casirivimab-imdevimab is a cocktail of 2 monoclonal antibodies designed to prevent infection by SARS-CoV-2, the virus that causes COVID-19. Casirivimab-imdevimab has been approved in Japan for treating mild to moderate COVID-19; however, to our knowledge, there are no reports of its use after kidney transplant from a live donor. Everolimus, an antineoplastic chemotherapy drug, is expected to be effective in inhibiting the spread of SARS-CoV-2 and preventing its replication, which may facilitate treatment. Here, we report a case of COVID-19 infection after kidney transplant that was initially treated with casirivimab-imdevimab and mycophenolate mofetil but was later changed to everolimus.

CASE REPORT

A 47-year-old man underwent living donor kidney transplant from his mother in 2017. Immunosuppression therapy was underway through the administration of tacrolimus, mycophenolate mofetil, and methylprednisolone. In early September 2021, he was diagnosed as having COVID-19 and was hospitalized on day 3. On hospitalization, mycophenolate mofetil was discontinued and casirivimab-imdevimab and heparin were started. The patient started an everolimus regimen on day 5. The clinical course was successful without rejection. There was no exacerbation of COVID-19; the patient's serum creatinine levels and renal function had otherwise remained stable.

CONCLUSIONS

We could safely treat a patient with casirivimab-imdevimab after kidney transplant. It is suggested that casirivimab-imdevimab can prevent COVID-19 from becoming severe and can be administered without worsening renal function. In addition, everolimus may have inhibited the spread of the virus and prevented it from replicating.

mTOR-Inhibition and COVID-19 in Kidney Transplant Recipients: Focus on Pulmonary Fibrosis

Kidney transplant recipients are at high risk of developing severe COVID-19 due to the coexistence of several transplant-related comorbidities (e.g., cardiovascular disease, diabetes) and chronic immunosuppression. As a consequence, a large part of SARS-CoV-2 infected patients have been managed with a reduction of immunosuppression. The mTOR-I, together with antimetabolites, have been often discontinued in order to minimize the risk of pulmonary toxicity and to antagonize pharmacological interaction with antiviral/anti-inflammatory drugs. However, at our opinion, this therapeutic strategy, although justified in kidney transplant recipients with severe COVID-19, should be carefully evaluated in asymptomatic/paucisymptomatic patients in order to avoid the onset of acute allograft rejections, to potentially exploit the mTOR-I antiviral properties, to reduce proliferation of conventional T lymphocytes (which could mitigate the cytokine storm) and to preserve Treg growth/activity which could reduce the risk of progression to severe disease. In this review, we discuss the current literature regarding the therapeutic potential of mTOR-Is in kidney transplant recipients with COVID-19 with a focus on pulmonary fibrosis.

Rapamycin: Drug Repurposing in SARS-CoV-2 Infection

Since December 2019, SARS-CoV-2 (COVID-19) has been a worldwide pandemic with enormous consequences for human health and the world economy. Remdesivir is the only drug in the world that has been approved for the treating of COVID-19. This drug, as well as vaccination, still has uncertain effectiveness. Drug repurposing could be a promising strategy how to find an appropriate molecule: rapamycin could be one of them. The authors performed a systematic literature review of available studies on the research describing rapamycin in association with COVID-19 infection. Only peer-reviewed English-written articles from the world’s acknowledged databases Web of Science, PubMed, Springer and Scopus were involved. Five articles were eventually included in the final analysis. The findings indicate that rapamycin seems to be a suitable candidate for drug repurposing. In addition, it may represent a better candidate for COVID-19 therapy than commonly tested antivirals. It is also likely that its efficiency will not be reduced by the high rate of viral RNA mutation.