SARS-CoV-2 Therapy: Old Drugs as New Interventions

An outburst of a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has become a grave threat to global health and the economy. As of May 13, 2020, a total of 42,81,838 cases have been confirmed, with over 2,92,376 deaths worldwide. In India, 75,048 cases have been reported to date with 2,440 deaths. Management of this new coronavirus (COVID19) has mainly focused on infection prevention, case detection, monitoring, and supportive care. As there is no vaccine or specific antiviral treatment for human SARS-CoV-2, therefore identifying the drug treatment options as soon as possible is critical for the response to the COVID19 outbreak. Pro-inflammatory cascade and cytokine storm play a key role in the pathogenesis of new coronavirus. A large number of therapeutic interventions such as antiviral, antimalarial, convalescent plasma therapy, BCG vaccine, mTOR inhibi-tors, Tissue Plasminogen Activator, Human monoclonal antibodies, Anti-parasitic agents, Immunoen-hancers, Nutritional interventions, JAK-STAT signaling inhibitors, ACE2 receptor modulators, and An-giotensin II receptor blockers have been either tried or suggested for effective treatment of patients with SARS-CoV-2 disease. Hence, we recommend that all the above potential interventions must be imple-mented in terms of their safety and efficacy through proper clinical experiments to control the emerging SARS-CoV-2 disease.Copyright © 2021 Bentham Science Publishers.

Impact of immunosuppression regimen on COVID-19 mortality in kidney transplant recipients: Analysis from a Colombian transplantation centers registry.

BACKGROUND: The impact of immunosuppression in solid organ transplant recipients with SARS-CoV-2 infection is unknown. The knowledge about the behavior of different immunosuppression schemes in clinical outcomes is scarce. This study aimed to determine the risk of death in kidney transplant recipients with COVID-19 under two different schemes of immunosuppression. METHODS: We describe our experience in kidney transplant recipients with SARS-CoV-2 infection in seven transplant centers during the first year of the pandemic before starting the vaccination programs in the city of Bogotá. Demographic characteristics, clinical presentation, immunosuppression schemes at presentation, and global treatment strategies were compared between recovered and dead patients; survival analysis was carried out between calcineurin inhibitors based regimen and free calcineurin inhibitors regimen. RESULTS: Among 165 confirmed cases, 28 died (17%); the risk factors for mortality identified in univariate analysis were age older than 60 years (p=.003) diabetes (p=.001), immunosuppression based on calcineurin inhibitors (CNI) (p=.025) and patients receiving steroids (p=.041). In multivariable analysis, hypoxemia (p=.000) and calcineurin inhibitors regimen (p=.002) were predictors of death. Survival analysis showed increased mortality risk in patients receiving CNI based immunosuppression regimen vs. CNI free regimens mortality rates were, respectively, 21.7% and 8.5% (p=.036). CONCLUSIONS: Our results suggest that the calcineurin inhibitors probably do not provide greater protection compared to calcineurin inhibitor free schemes being necessary to carry out analyzes that allow us to evaluate the outcomes with different immunosuppression schemes in solid organ transplant recipients with SARS-CoV-2 infection.

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.

PI3K/Akt/mTOR pathway: a potential target for anti-SARS-CoV-2 therapy.

Coronavirus disease 2019 (COVID-19) is a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A single-stranded RNA virus from a ß-Coronaviridae family causes acute clinical manifestations. Its high death rate and severe clinical symptoms have turned it into the most significant challenge worldwide. Up until now, several effective COVID-19 vaccines have been designed and marketed, but our data on specialized therapeutic drugs for the treatment of COVID-19 is still limited. In order to synthesis virus particles, SARS-CoV-2 uses host metabolic pathways such as phosphoinositide3-kinase (PI3K)/protein kinase B (PKB, also known as AKT)/mammalian target of rapamycin (mTOR). mTOR is involved in multiple biological processes. Over-activation of the mTOR pathway improves viral replication, which makes it a possible target in COVID-19 therapy. Clinical data shows the hyperactivation of the mTOR pathway in lung tissues during respiratory viral infections. However, the exact impact of mTOR pathway inhibitors on the COVID-19 severity and death rate is yet to be thoroughly investigated. There are several mTOR pathway inhibitors. Rapamycin is the most famous inhibitor of mTORC1 among all. Studies on other respiratory viruses suggest that the therapeutic inhibitors of the mTOR pathway, especially rapamycin, can be a potential approach to anti-SARS-CoV-2 therapy. Using therapeutic methods that inhibit harmful immune responses can open a new chapter in treating severe COVID-19 disease. We highlighted the potential contribution of PI3K/Akt/mTOR inhibitors in the treatment of COVID-19.

The PI3K/Akt/mTOR pathway: A potential pharmacological target in COVID-19.

Coronavirus disease 2019 (COVID-19) has emerged as a serious threat to global health. The disregulation of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) cell signaling pathway observed in patients with COVID-19 has attracted attention for the possible use of specific inhibitors of this pathway for the treatment of the disease. Here, we review emerging data on the involvement of the PI3K/Akt/mTOR pathway in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the clinical studies investigating its tailored inhibition in COVID-19. Current in silico, in vitro, and in vivo data convergently support a role for the PI3K/Akt/mTOR pathway in COVID-19 and suggest the use of specific inhibitors of this pathway that, by a combined mechanism entailing downregulation of excessive inflammatory reactions, cell protection, and antiviral effects, could ameliorate the course of COVID-19.

mTOR inhibitors improve both humoral and cellular response to SARS-CoV-2 messenger RNA BNT16b2 vaccine in kidney transplant recipients.

Kidney transplant recipients (KTRs) have been considered as patients at higher risk of SARS-CoV-2-related disease severity, thus COVID-19 vaccination was highly recommended. However, possible interferences of different immunosuppression with development of both humoral and T cell-mediated immune response to COVID-19 vaccination have not been determined. Here we evaluated the association between mTOR-inhibitors (mTOR-I) and immune response to mRNA BNT162b2 (Pfizer-BioNTech) vaccine in KTR. To this aim 132 consecutive KTR vaccinated against COVID-19 in the early 2021 were enrolled, and humoral and T cell-mediated immune response were assessed after 4-5 weeks. Patients treated with mTOR-I showed significantly higher anti-SARS-CoV-2 IgG titer (p = .003) and higher percentages of anti-SARS-CoV-2 S1/RBD Ig (p = .024), than those without. Moreover, SARS-CoV-2-specific T cell-derived IFNγ release was significantly increased in patients treated with mTOR-I (p < .001), than in those without. Multivariate analysis confirmed that therapy with mTOR-I gained better humoral (p = .005) and T cell-mediated immune response (p = .005) in KTR. The presence of mTOR-I is associated with a better immune response to COVID-19 vaccine in KTR compared to therapy without mTOR-I, not only by increasing vaccine-induced antibodies but also by stimulating anti-SARS-CoV-2 T cell response. These finding are consistent with a potential beneficial role of mTOR-I as modulators of immune response to COVID-19 vaccine in KTR.

Can We Use mTOR Inhibitors for COVID-19 Therapy?

Infection by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) provokes acute inflammation due to extensive replication of the virus in the epithelial cells of the upper and lower respiratory system. The mammalian target of rapamycin (mTOR) is a l signalling protein with critical functions in cell growth, metabolism, and proliferation. It is known for its regulatory functions in protein synthesis and angiogenesis cascades. The structure of mTOR consists of two distinct complexes (mTORC1 and mTORC2) with diverse functions at different levels of the signalling pathway. By activating mRNA translation, the mTORC1 plays a key role in regulating protein synthesis and cellular growth. On the other hand, the functions of mTORC2 are mainly associated with cell proliferation and survival. By using an appropriate inhibitor at the right time, mTOR modulation could provide immunosuppressive opportunities as antirejection regimens in organ transplantation as well as in the treatment of autoimmune diseases and solid tumours. The mTOR also has an important role in the inflammatory process. Inhibitors of mTOR might indeed be promising agents in the treatment of viral infections. They have further been successfully used in patients with severe influenza A/H1N1 pneumonia and acute respiratory failure. The officially accepted mTOR inhibitors that have undergone clinical testing are sirolimus, everolimus, temsirolimus, and tacrolimus. Thus, further studies on mTOR inhibitors for SARS-CoV-2 infection or COVID-19 therapy are well merited.

Sirolimus in a Renal Transplant Recipient Infected With COVID-19: A Blessing in Disguise?

Immunocompromised status Is often associated with severe coronavirus infection given the inability of the immune system to combat the deadly severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Patients with multiple comorbidities such as diabetes mellitus, hypertension, and chronic kidney disease along with patients on immunosuppressants or chemotherapy are at higher risk of getting infected during the ongoing pandemic with more probability of adverse outcomes. However, we report a rare case of a renal transplant recipient who was on sirolimus and contracted coronavirus disease (COVID-19). His immunosuppressants were continued and he was managed with antiviral, steroids and low molecular weight heparin and the patient responded well to the treatment and recovered completely after a span of one week. Use of sirolimus in a patient with renal transplant recipient helped in preventing intensification of the severity in COVID-19 attributing to its inhibiting effect on mammalian target of rapamycin (mTOR) which he was using post his renal transplant, therefore, proving to be a blessing in disguise.

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.

A new application of mTOR inhibitor drugs as potential therapeutic agents for COVID-19.

Since December 2019, the COVID-19 emerging pandemic caused by SARS-CoV-2 has resulted in one of the most important global health threats. Concerning the absence of an approved effective vaccine or drug for the treatment and outcome improvement of COVID-19 patients, and the role of SARS-CoV-2 in activation of mammalian target of rapamycin (mTOR) pathway, we decided to review the previous data regarding the therapeutic effect of mTOR inhibitor drugs in COVID-19 patients. We searched the scientific databases such as Web of Science, Embase, Medline (PubMed), Scopus, and Google Scholar using appropriate keywords to find suitable studies or suggestions until October 2020. The findings of the current study confirmed that mTOR inhibitor drugs through suggested mechanisms such as T cell adjustment, induction of autophagy without apoptosis, reduction of viral replication, restoration of the T-cell function, decrease cytokine storm, and moderation of the mTOR-PI3K-AKT pathway activation bring about a therapeutic impact in COVID-19 patients. Taken together, it is necessary to find a suitable therapy for the COVID-19 pandemic emerging. In this regard, we clarify that it is valuable to consider the therapeutic effect of mTOR inhibitor drugs and metformin by its mTOR inhibition property in the treatment of COVID-19 patients.

Immunosuppressive Drugs and COVID-19: A Review.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is currently unknown whether immunosuppressive drugs are advantageous or detrimental in patients with COVID-19. Immunosuppressive drugs could be harmful in the initial phase of COVID-19. In this phase, the host immune response is necessary to inhibit viral replication. However, immunosuppressive drugs might have a beneficial effect in the later, more severe phase of COVID-19. In this phase, an overshoot of the host immune response (the "cytokine storm") can cause ARDS, multiorgan failure and mortality. AIM: To summarize the available evidence on the effect of immunosuppressive drugs on infection with SARS-CoV-2. The effects of immunosuppressive drugs on similar pandemic coronaviruses may resemble the effects on SARS-CoV-2. Thus, we also included studies on the severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). METHODS: The study protocol was registered in PROSPERO (registration number CRD42020181137). We included randomized controlled trials (RCTs), cohort studies with a control group and case-control studies concerning humans ≥ 18 years old. We also included in-vitro studies and animal studies with a control group. RESULTS AND CONCLUSION: Sixty-nine studies were included. Interestingly, MPA inhibits SARS-CoV-2 replication in-vitro. Clinical studies are needed to confirm the inhibitory effect of MPA on SARS-CoV-2 replication in-vivo. There are indications that corticosteroids and IL-6 inhibitors, like tocilizumab, can reduce mortality and prevent mechanical ventilation in patients with COVID-19. However, observational studies have contradictory results and the risk of bias is high. Thus, these results have to be confirmed in high-quality clinical trials before these drugs can be implemented as standard care. Based on the positive results of CNIs, mTOR inhibitors and thiopurine analogues in in-vitro studies with SARS-CoV and MERS-CoV, it would be interesting to investigate their effects on SARS-CoV-2 replication.