COVID-19 and its clinical severity are associated with alterations of plasma sphingolipids and enzyme activities of sphingomyelinase and ceramidase (preprint)

In the current pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; COVID-19), a better understanding of the underlying mechanisms is essential to reduce morbidity and mortality and treat post-COVID-19 disease. Here, we analyzed alterations of sphingolipids and their metabolizing enzymes in 125 men and 74 women tested positive for SARS-CoV-2 and hospitalized with mild, moderate or severe symptoms or after convalescence. The activities of acid and neutral sphingomyelinases (ASM, NSM), which hydrolyze sphingomyelin to ceramide, were significantly increased in COVID-19 patients, while the activity of neutral ceramidase (NC), which hydrolyzes ceramide to sphingosine, was reduced. These alterations could each contribute to elevated ceramide levels in patients. Accordingly, liquid chromatography tandem-mass spectrometry (LC-MS/MS) yielded increased levels of ceramides 16:0 and 18:0 with highest levels in severely affected patients and similar effects for dihydroceramides 16:0 and 18:0, whereas levels of (dihydro-)ceramides 24:0 were reduced. Furthermore, sphingomyelin 20:0; 22:0 and 24:0 as substrates of ASM and NSM as well as their dihydrosphingomyelin counterparts were reduced in patients as well as sphingosine-1-phosphate further downstream of NC activity. Effects of NSM, NC, ceramides and sphingomyelins remained significant after Bonferroni correction. SARS-CoV-2 antibody levels in convalescent patients were associated with age but none of the sphingolipid parameters. Based on our data, COVID-19 is associated with a dysregulation of sphingolipid homeostasis in a severity-dependent manner, particularly focused around a reduction of sphingomyelins and an accumulation of ceramides by increased enzyme activities leading to ceramide elevation (ASM, NSM) combined with a decreased activity of enzymes (NC) reducing ceramide levels. The potential of a combined sphingolipid/enzyme pattern as a diagnostic and prognostic marker and therapeutic target deserves further exploration.

Association between Functional Inhibitors of Acid Sphingomyelinase and Reduced Risk of Intubation or Death in Individuals Hospitalized for Severe COVID-19: results from an observational multicenter study (preprint)

Several medications commonly used for a number of medical conditions share a property of functional inhibition of acid sphingomyelinase (ASM), or FIASMA. Preclinical and clinical evidence suggest that the (ASM)/ceramide system may be central to SARS-CoV-2 infection. We examined the potential usefulness of FIASMA use among patients hospitalized for severe COVID-19 in an observational multicenter retrospective study conducted at Greater Paris University hospitals. Of 2,846 adult patients hospitalized for severe COVID-19, 277 (9.7%) were taking a FIASMA medication at the time of their hospital admission. The primary endpoint was a composite of intubation and/or death. We compared this endpoint between patients taking vs. not taking a FIASMA medication in time-to-event analyses adjusted for sociodemographic characteristics and medical comorbidities. The primary analysis was a Cox regression model with inverse probability weighting (IPW). Over a mean follow-up of 9.2 days (SD=12.5), the primary endpoint occurred in 104 patients (37.5%) who were taking a FIASMA medication, and 1,060 patients (41.4%) who were not. Taking a FIASMA medication was associated with reduced likelihood of intubation or death in both crude (HR=0.71; 95%CI=0.58-0.87; p<0.001) and the primary IPW (HR=0.58; 95%CI=0.46-0.72; p<0.001) analyses. This association remained significant in multiple sensitivity analyses and was not specific to one FIASMA class or medication. These results show the potential importance of the ASM/ceramide system as a treatment target in COVID-19. Double-blind controlled randomized clinical trials of these medications for COVID-19 are needed.

Association between benzodiazepine receptor agonist use and increased mortality among patients hospitalized for COVID-19: results from an observational study (preprint)

ObjectiveTo examine the association between benzodiazepine receptor agonist (BZRA) use and mortality in patients hospitalized for COVID-19. MethodsWe conducted an observational multicenter retrospective cohort study at AP-HP Greater Paris University hospitals. The sample involved 14,381 adult patients hospitalized for COVID-19. 686 (4.8%) inpatients received a BZRA within at the time of hospital admission at a mean daily diazepam-equivalent dose of 19.7 mg (SD=25.4). The study baseline was the date of hospital admission and the primary endpoint was death. We compared this endpoint between patients who received BZRAs and those who did not in time-to-event analyses adjusted for patient characteristics (such as age, sex, obesity and comorbidity) and other medications. The primary analysis was a Cox regression model with inverse probability weighting (IPW). ResultsOver a mean follow-up of 14.5 days (SD=18.1), the primary endpoint occurred in 186 patients (27.1%) who received a BZRA and in 1,134 patients (8.3%) who did not. There was a significant association between BZRA use and increased mortality both in the crude analysis (HR=3.20; 95% CI=2.74-3.74; p<0.01) and in the primary IPW analysis (HR=1.61; 95% CI=1.31-1.98, p<0.01), with a significant dose-dependent relationship (HR=1.55; 95% CI=1.08-2.22; p=0.02). This association remained significant in multiple sensitivity analyses. ConclusionsBZRA use was associated with increased mortality among patients hospitalized for COVID-19 with a dose-dependent relationship, suggesting a potential benefit of decreasing dose or tapering off these medications when possible in these patients.

Association between Psychotropic Medications Functionally Inhibiting Acid Sphingomyelinase and reduced risk of Intubation or Death among Individuals with Mental Disorder and Severe COVID-19: an Observational Study (preprint)

ABSTRACT Prior preclinical and clinical evidence suggests that the acid sphingomyelinase (ASM)/ceramide system may provide a useful framework for better understanding SARS-CoV-2 infection and the repurposing of psychotropic medications with functional inhibition of acid sphingomyelinase, called FIASMA psychotropic medications, against COVID-19. We examined the potential usefulness of FIASMA psychotropic medication use among patients with mental disorder hospitalized for severe COVID-19, in an observational multicenter retrospective study conducted at AP-HP Greater Paris University hospitals. Of 545 adult patients with mental disorder hospitalized for severe COVID-19, 164 (30.1%) received a psychotropic FIASMA medication at study baseline, which was defined as the date of hospital admission for COVID-19. The primary endpoint was a composite of intubation or death. We compared this endpoint between patients who received a psychotropic FIASMA medication at baseline and those who did not in time-to-event analyses adjusted for sociodemographic characteristics, psychiatric and other medical comorbidity, and psychotropic and other medications. The primary analysis was a Cox regression model with inverse probability weighting (IPW). There was a significant association between FIASMA psychotropic medication use at baseline and reduced risk of intubation or death both in the crude analysis (HR=0.42; 95%CI=0.31-0.57; p<0.01) and in the primary IPW analysis (HR=0.50; 95%CI=0.37-0.67; p<0.01). This association remained significant in multiple sensitivity analyses. Exploratory analyses suggested that this association was not specific to one FIASMA psychotropic class or medication. These results suggest the usefulness of the ASM/ceramide system framework in COVID-19. Double-blind controlled randomized clinical trials of these medications for COVID-19 are needed.

Inhibition of Acid Sphingomyelinase Blocks Infection with SARS-CoV-2 (preprint)

We have previously shown that the acid sphingomyelinase/ceramide system plays an important role in bacterial and viral infections. Pharmacological inhibition of acid sphingomyelinase with amitriptyline, imipramine, fluoxetine, sertraline, escitalopram or maprotiline or genetic down-regulation of the enzyme prevents infection with authentic SARS-CoV-2 or pseudoviral particles expressing pp-VSV-SARS-CoV-2 spike that served as a bona fide system mimicking SARS-CoV-2 infection. Mechanistically, acid sphingomyelinase mediates the formation of ceramide-enriched membrane platforms that serve the infection with pp-VSV-SARS-CoV-2 spike. Neutralization or consumption of surface ceramide reduces infection with pp-VSV-SARS-CoV-2 spike. Treatment of volunteers with a low dose of amitriptyline prevents infection of freshly isolated nasal epithelial cells with pp-VSV-SARS-CoV-2 spike, indicating that amitriptyline can be repurposed to prevent SARS-CoV-2 infection. Our data suggest the use of amitriptyline, a safe drug clinically used for almost 60 years, other antidepressants blocking the acid sphingomyelinase, anti-ceramide antibodies and neutral ceramidase for prophylaxis and treatment of coronavirus disease-19.Funding: The study was supported by DFG grant Gu-335-35/1 and BMBF, RAPID Consortium,grant 01KI1723D to SP.Conflict of Interest: The authors declare no competing financial interests.Ethical Approval: The experiments were approved by the local ethics committee under the number 20-9348-BO.