A mid‑pandemic night’s dream: Melatonin, from harbinger of anti‑inflammation to mitochondrial savior in acute and long COVID‑19 (Review)

Abstract:

Coronavirus disease 2019 (COVID‑19), a systemic illness caused by severe acute respiratory distress syndrome 2 (SARS‑CoV‑2), has triggered a worldwide pandemic with symptoms ranging from asymptomatic to chronic, affecting practically every organ. Melatonin, an ancient antioxidant found in all living organisms, has been suggested as a safe and effective therapeutic option for the treatment of SARS‑CoV‑2 infection due to its good safety characteristics and broad‑spectrum antiviral medication properties.

Melatonin is essential in various metabolic pathways and governs physiological processes, such as the sleep‑wake cycle and circadian rhythms. It exhibits oncostatic, anti‑inflammatory, antioxidant and anti‑aging properties, exhibiting promise for use in the treatment of numerous disorders, including COVID‑19. The preventive and therapeutic effects of melatonin have been widely explored in a number of conditions and have been well‑established in experimental ischemia/reperfusion investigations, particularly in coronary heart disease and stroke.

Clinical research evaluating the use of melatonin in COVID‑19 has shown various improved outcomes, including reduced hospitalization durations; however, the trials are small. Melatonin can alleviate mitochondrial dysfunction in COVID‑19, improve immune cell function and provide antioxidant properties. However, its therapeutic potential remains underexplored due to funding limitations and thus further investigations are required.

Source: Lempesis IG, Georgakopoulou VE, Reiter RJ, Spandidos DA. A mid‑pandemic night’s dream: Melatonin, from harbinger of anti‑inflammation to mitochondrial savior in acute and long COVID‑19 (Review). Int J Mol Med. 2024 Mar;53(3):28. doi: 10.3892/ijmm.2024.5352. Epub 2024 Feb 1. PMID: 38299237. https://www.spandidos-publications.com/10.3892/ijmm.2024.5352

Effect of Paxlovid Treatment on Long COVID Onset: An EHR-Based Target Trial Emulation from N3C

Abstract:

Preventing and treating post-acute sequelae of SARS-CoV-2 infection (PASC), commonly known as Long COVID, has become a public health priority. In this study, we examined whether treatment with Paxlovid in the acute phase of COVID-19 helps prevent the onset of PASC.

We used electronic health records from the National Covid Cohort Collaborative (N3C) to define a cohort of 426,461 patients who had COVID-19 since April 1, 2022, and were eligible for Paxlovid treatment due to risk for progression to severe COVID-19. We used the target trial emulation (TTE) framework to estimate the effect of Paxlovid treatment on PASC incidence.

Our primary outcome measure was a PASC computable phenotype. Secondary outcomes were the onset of novel cognitive, fatigue, and respiratory symptoms in the post-acute period. Paxlovid treatment did not have a significant effect on overall PASC incidence (relative risk [RR] = 0.99, 95% confidence interval [CI] 0.96-1.01). However, its effect varied across the cognitive (RR = 0.85, 95% CI 0.79-0.90), fatigue (RR = 0.93, 95% CI 0.89-0.96), and respiratory (RR = 0.99, 95% CI 0.95-1.02) symptom clusters, suggesting that Paxlovid treatment may help prevent post-acute cognitive and fatigue symptoms more than others.

Source: Alexander Preiss, Abhishek Bhatia, Chengxi Zang, Leyna V. Aragon, John M. Baratta, Monika Baskaran, Frank Blancero, M. Daniel Brannock, Robert F. Chew, Iván Díaz, Megan Fitzgerald, Elizabeth P. Kelly, Andrea Zhou, Mark G. Weiner, Thomas W. Carton, Fei Wang, Rainu Kaushal, Christopher G. Chute, Melissa Haendel, Richard Moffitt, Emily Pfaff. Effect of Paxlovid Treatment on Long COVID Onset: An EHR-Based Target Trial Emulation from N3C. medRxiv 2024.01.20.24301525; doi: https://doi.org/10.1101/2024.01.20.24301525 https://www.medrxiv.org/content/10.1101/2024.01.20.24301525v1.full-text (Full text)

Low-Dose Naltrexone Improves post-COVID-19 condition Symptoms

Abstract:

Purpose: Treatments for myalgic encephalomyelitis and chronic fatigue syndrome can be adapted for post-COVID-19 condition. Our aim was to compare treatments in patients from our post-COVID-19 clinic.

Methods: We conducted a retrospective cohort study and included consecutive patients enrolled in our post-COVID-19 clinic. We included patients who received low-dose naltrexone, amitriptyline, duloxetine, and physical therapy, and evaluated improvements in fatigue, pain, dyspnea, and brain fog recorded in the electronic health record. We calculated the adjusted relative hazard of improvement using Cox proportional models. We adjusted for demographic characteristics, comorbidities, and prior COVID-19 hospitalization.

Findings: We included the first 108 patients with post-COVID-19 enrolled in the clinic. Most of the patients received amitriptyline. The relative hazard of improvement for those taking low-dose naltrexone was 5.04 (95% CI, 1.22-20.77; P = 0.02) compared with physical therapy alone. Both fatigue and pain were improved in patients taking low-dose naltrexone; only fatigue was improved in patients taking amitriptyline.

Implications: Post-COVID-19 condition symptoms may improve in patients taking medications adapted from myalgic encephalomyelitis and chronic fatigue syndrome. Randomized controlled trials should evaluate these medications and translational studies should further evaluate their mechanisms of action.

Source: Tamariz L, Bast E, Klimas N, Palacio A. Low-Dose Naltrexone Improves post-COVID-19 condition Symptoms. Clin Ther. 2024 Jan 23:S0149-2918(24)00003-1. doi: 10.1016/j.clinthera.2023.12.009. Epub ahead of print. PMID: 38267326. https://pubmed.ncbi.nlm.nih.gov/38267326/

Randomised clinical trials with hyperbaric oxygen in COVID-19 and Long COVID : transcriptomic insights into benefits and harms

Abstract:

The flow from transcription of genes through translation and processing of proteins is a common basis for all life. Redox homeostasis is crucial for the defence against oxidative stress. We adapt through hormesis; non-lethal stress regulates redox-sensitive systems to maintain homeostasis. If the stress is chronic or acutely overwhelming, the cells can either go into apoptosis or into senescence to maintain homeostasis. Similar effects have been seen with HBOT as with intermittent oxygen deprivation. Hyperbaric oxygen therapy (HBOT) is delivered in a pressure chamber by breathing 100% oxygen intermittently, several times a week, in an ambient pressure equivalent to 10-20 meters of seawater. The aim of this thesis was to evaluate potential harms of HBOT for novel indications and to explore biomarkers in experimental and clinical trials in order to enable future precision medicine. We used methods evaluated on healthy volunteers in randomised clinical trials (RCTs) conducted in compliance with good clinical practice (ICH-GCP).

In Paper I, we evaluated Electron paramagnetic resonance (EPR) spectroscopy for measuring reactive oxygen species (ROS) in blood and RNA sequencing (RNAseq) of monocytes in peripheral blood (PBMC), and compared HBOT and HIIT in ten healthy volunteers. We could measure ROS in blood in the same physiological range in both interventions. We also discovered pathways involved in adaption to hypoxia and inflammation that were similar in both interventions. In Papers II and III, we evaluated harms and explored RNAseq in PBMC in an open label RCT where 31 patients with severe COVID- 19 were randomised to HBOT or best practice. We observed similar frequencies of adverse events (AEs) in the two groups and could not see any negative effect on vital signs or oxygenation. We discovered a unique transcriptomic signature in the subjects that had received HBOT. The differentially expressed genes were associated with the unfolded protein response, apoptosis, and immune response. In Paper IV, we evaluated harms and described health related quality of life (HRQoL)in an interim analysis of the first 20 subjects froma placebo controlled RCT where 80 patients with Long COIVD were randomised to HBOT or sham treatment. We reported more AEs than expected and severe physical and mental disabilities with a very poor HRQoL. Most AEs were mild, and all were transient.

We have shown that HBOT shares similarities in immune response with HIIT in healthy volunteers. HBOT has a favourable profile of harms and has a potent immunomodulatory effect that is associated with fast recovery for critical COVID-19 patients. HBOT has a favourable profile of harms for patients with post COVID-19 condition. The results provide a base for future clinical trials with HBOT.

Source: Kjellberg, Anders. Randomised clinical trials with hyperbaric oxygen in COVID-19 and Long COVID : transcriptomic insights into benefits and harms. Thesis: Karolinska Institute, Dept of Physiology and Pharmacology. https://openarchive.ki.se/xmlui/handle/10616/48928 (Full study available as PDF file)

A randomized open-label clinical trial on the effect of Amantadine on post Covid 19 fatigue

Abstract:

Many COVID-19 survivors experience lingering post-COVID-19 symptoms, notably chronic fatigue persisting for months after the acute phase. Despite its prevalence, limited research has explored effective treatments for post-COVID-19 fatigue. This randomized controlled clinical trial assessed the impact of Amantadine on patients with post-COVID-19 fatigue.

The intervention group received Amantadine for two weeks, while the control group received no treatment. Fatigue levels were assessed using the Visual Analog Fatigue Scale (VAFS) and Fatigue Severity Scale (FSS) questionnaires before and after the trial. At the study’s onset, VAFS mean scores were 7.90 ± 0.60 in the intervention group and 7.34 ± 0.58 in the control group (P-value = 0.087). After two weeks, intervention group scores dropped to 3.37 ± 0.44, significantly lower than the control group’s 5.97 ± 0.29 (P-value < 0.001). Similarly, FSS mean scores at the trial’s commencement were 53.10 ± 5.96 in the intervention group and 50.38 ± 4.88 in the control group (P-value = 0.053). At the trial’s end, intervention group scores decreased to 28.40 ± 2.42, markedly lower than the control group’s 42.59 ± 1.50 (P-value < 0.001).

In this study, we report the safety, tolerability, and substantial fatigue-relieving effects of Amantadine in post-COVID-19 fatigue. The intervention demonstrates a statistically significant reduction in fatigue levels, suggesting Amantadine’s potential as an effective treatment for this persistent condition.

Source: Harandi, A.A., Pakdaman, H., Medghalchi, A. et al. A randomized open-label clinical trial on the effect of Amantadine on post Covid 19 fatigue. Sci Rep 14, 1343 (2024). https://doi.org/10.1038/s41598-024-51904-z https://www.nature.com/articles/s41598-024-51904-z (Full text)

Dermatologic Changes in Experimental Model of Long-COVID

Abstract:

The COVID-19 pandemic, declared in early 2020, is an unprecedented global health crisis, causing over 7.0 million deaths and ongoing challenges. While the pharmaceutical industry expedited vaccine development, mutant SARS-CoV-2 strains remain a major fear. Moreover, concerns regarding the long-term health repercussions of COVID-19-affected individuals persist since individuals affected by mild and moderate to severe SARS-CoV-2 infection experience long-term cardiovascular complications, liver dysfunction, pulmonary afflictions, kidney impairments, and most importantly neurocognitive deficits.
In recent studies, we documented pathophysiological changes in various organs following the post-acute infection of mice with murine hepatitis virus-1 (MHV-1), a coronavirus, at both 7 days and 12 months after infection. One part of the body that can be drastically affected by SARS-CoV-2 is the skin. Studies have shown major changes in the skin post-acute SARS CoV-2 infection in humans. However, long-term dermatologic changes post-COVID have never been explored.
For the first time, we show several cutaneous findings both at the acute stages and long-term post-infection of mice with MHV-1 coronavirus (a promising experimental model to study acute and long-COVID). Precisely, we found destruction of the epidermal layer, an increase in the number of hair follicles, extensive collagen deposition in the dermal layer, and hyperplasticity of the sebaceous glands at the acute stages, along with thinning of the panniculus carnosus, as well as the adventitial layer, which corresponds well with studies in humans.
In contrast, the cutaneous investigation in the long-COVID phase shows the absence of hair follicles from both the epidermal and dermal layers, the destruction of adipose tissues, and the devastation of the epidermal layer. Further, treatment of these mice with a 15 amino acid synthetic peptide, SPIKENET (SPK), which was effective in preventing Spike glycoprotein-1 binding with host receptors, as well as has a potent anti-inflammatory response to severe inflammatory stimulus) restored the loss of hair follicles and re-architected the epidermal and dermal layers.
Additionally, destruction in fatty tissue in the infected mice was successfully restored post-treatment with SPK. These findings suggest that SARS-CoV-2 initiates the changes early post-infection, leading to devastating skin alterations in the long term which can be prevented by our newly identified peptide drug SPK.
Source: Hussain, H.; Paidas, M.J.; Rajalakshmi, R.; Fadel, A.; Ali, M.; Chen, P.; Jayakumar, A.R. Dermatologic Changes in Experimental Model of Long-COVID. Preprints 2023, 2023122339. https://doi.org/10.20944/preprints202312.2339.v1 https://www.preprints.org/manuscript/202312.2339/v1 (Full text available as PDF file)

Cannabinoids and the Endocannabinoid System in Early SARS-CoV-2 Infection and Long COVID-19—A Scoping Review

Abstract:

Coronavirus disease-19 (COVID-19) is a highly contagious illness caused by the SARS-CoV-2 virus. The clinical presentation of COVID-19 is variable, often including symptoms such as fever, cough, headache, fatigue, and an altered sense of smell and taste. Recently, post-acute “long” COVID-19 has emerged as a concern, with symptoms persisting beyond the acute infection. Vaccinations remain one of the most effective preventative methods against severe COVID-19 outcomes and the development of long-term COVID-19. However, individuals with underlying health conditions may not mount an adequate protective response to COVID-19 vaccines, increasing the likelihood of severe symptoms, hospitalization, and the development of long-term COVID-19 in high-risk populations.
This review explores the potential therapeutic role of cannabinoids in limiting the susceptibility and severity of infection, both pre- and post-SARS-CoV-19 infection. Early in the SARS-CoV-19 infection, cannabinoids have been shown to prevent viral entry, mitigate oxidative stress, and alleviate the associated cytokine storm. Post-SARS-CoV-2 infection, cannabinoids have shown promise in treating symptoms associated with post-acute long COVID-19, including depression, anxiety, post-traumatic stress injury, insomnia, pain, and decreased appetite. While current research primarily focuses on potential treatments for the acute phase of COVID-19, there is a gap in research addressing therapeutics for the early and post-infectious phases. This review highlights the potential for future research to bridge this gap by investigating cannabinoids and the endocannabinoid system as a potential treatment strategy for both early and post-SARS-CoV-19 infection.
Source: Scott C, Hall S, Zhou J, Lehmann C. Cannabinoids and the Endocannabinoid System in Early SARS-CoV-2 Infection and Long COVID-19—A Scoping Review. Journal of Clinical Medicine. 2024; 13(1):227. https://doi.org/10.3390/jcm13010227 https://www.mdpi.com/2077-0383/13/1/227 (Full text)

Analysis of post-COVID symptoms and predisposing factors for chronic post-COVID syndrome

Abstract:

Introduction: While there is sufficient information about acute COVID-19, which can cause a multisystemic and fatal disease, post-COVID syndrome and risk factors for this condition remain poorly known. We aimed to identify postCOVID symptoms and risk factors for chronic post-COVID syndrome through this study.

Materials and methods: This prospective cross-sectional study was conducted on 254 out of 384 COVID-19 patients admitted to our COVID-19 polyclinic between February and April 2021. The patients were questioned with a list of 37 symptoms at the fifth and twelfth weeks after disease onset via phone review, and their acute post-COVID (APC) and chronic post-COVID (CPC) symptoms were recorded. Data on risk factors were collected from the hospital’s medical records system. Associations between symptom count in the CPC phase and age, sex, hospitalization, RT-PCR result, specific radiological findings, comorbidities, and long-term medications were evaluated.

Result: Two hundred twenty-one patients had APC symptoms, and 138 patients had CPC symptoms. While the most common symptom was fatigue at week five, it was hair loss at week 12. Symptoms were observed significantly less in the CPC phase than in the APC phase (Z= -12.301, p= 0.00). Female sex and the presence of specific radiological findings were significantly associated with the occurrence of CPC symptoms (p= 0.03, p= 0.00, respectively). Long-term use of angiotensin-2 receptor blockers (ARBs) was correlated with a low symptom count in the CPC phase (p= 0.00).

Conclusions: Female sex and the presence of specific radiological findings were risk factors for developing CPC. Long-term use of ARBs was associated with a low chronic post-COVID symptom burden. A substantial cluster of multisystemic symptoms was observed in both phases, and this condition highlights the requirement for customized outpatient management that includes long-term follow-up and treatment of COVID-19 patients. Identifying the high-risk patients that will develop persistent symptoms can guide this management.

Source: Abalı H, Demir D, Gül Ş, Şimşek Veske N, Tural Onur S. Analysis of post-COVID symptoms and predisposing factors for chronic post-COVID syndrome. Tuberk Toraks. 2023 Dec;71(4):378-389. English. doi: 10.5578/tt.20239606. PMID: 38152008. https://pubmed.ncbi.nlm.nih.gov/38152008/ (Full text available as PDF file)

Long Covid, the Gut, and Autoimmune Skin Diseases: A Novel Therapeutic Approach

Abstract:

The dermatological manifestations of Long Covid (LC) have languished in the shadows of chronic fatigue and brain fog. Yet they are all linked by gut dysbiosis and the cytokine triad of TNF-α, IL-1β, and IL-6. The gut microbiome common not only to LC, psoriasis, AA, and vitiligo but also to neurodegenerative disease has been recently described. This gut microbiome induces an altered tryptophan metabolism linked to autoimmune disease. SARS CoV2 invades enterochromaffin cells rich in ACE2 receptors and curtails absorption of the essential amino acid tryptophan and subsequent synthesis of serotonin and melatonin.

This review suggests that an etiologic prebiotic (d-mannose)/probiotic (lactobacilli, bifidobacteria)/postbiotic (butyrate) approach to autoimmune skin disease that improves intestinal barrier integrity and that suppresses the triad of TNF-α, IL-6, and IL-1β may enhance or even eliminate the traditional immunotherapy of targeted monoclonal antibodies, Janus kinase inhibitors, and steroids. Health benefits of this approach extend well beyond suppression of autoimmune skin disease.

Source: Chambers, P.W.; Chambers, S.E. Long Covid, the Gut, and Autoimmune Skin Diseases: A Novel Therapeutic Approach. Preprints 2023, 2023121881. https://doi.org/10.20944/preprints202312.1881.v2 https://www.preprints.org/manuscript/202312.1881/v2 (Full text available as PDF file)

Identification of CD8 T-cell dysfunction associated with symptoms in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID and treatment with a nebulized antioxidant/anti-pathogen agent in a retrospective case series

Highlights:

• Both Long COVID and ME/CFS are characterized by dysfunctional CD8 T-cells with severe deficiencies in their abilities to produce IFNγ and TNFα.

• In a small Long COVID and ME/CFS case series, patients’ immune deficiency and health improve during treatment period with a nebulized antioxidant, anti-pathogen and immune-modulatory pharmacological agent.

• This work provides evidence of a useful biomarker, CD8 T-cell dysfunction reminiscent of T cell exhaustion, that may assist diagnosis and have utility for tracking disease outcome during therapy, including response to a potential new treatment.

Abstract:

Background: Patients with post-acute sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection (PASC, i.e., Long COVID) have a symptom complex highly analogous to many features of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), suggesting they may share some aspects of pathogenesis in these similar disorders. ME/CFS is a complex disease affecting numerous organ systems and biological processes and is often preceded by an infection-like episode. It is postulated that the chronic manifestations of illness may result from an altered host response to infection or inability to resolve inflammation, as is being reported in Long COVID. The immunopathogenesis of both disorders is still poorly understood. Here, we show data that suggest Long COVID and ME/CFS may be due to an aberrant response to an immunological trigger-like infection, resulting in a dysregulated immune system with CD8 T-cell dysfunction reminiscent of some aspects of T-cell clonal exhaustion, a phenomenon associated with oxidative stress. As there is an urgent need for diagnostic tools and treatment strategies for these two related disabling disorders, here, in a retrospective case series, we have also identified a potential nebulized antioxidant/anti-pathogen treatment that has evidence of a good safety profile. This nebulized agent is comprised of five ingredients previously reported individually to relieve oxidative stress, attenuate NF-κB signaling, and/or to act directly to inhibit pathogens, including viruses. Administration of this treatment by nebulizer results in rapid access of small doses of well-studied antioxidants and agents with anti-pathogen potential to the lungs; components of this nebulized agent are also likely to be distributed systemically, with potential to enter the central nervous system.

Methods and Findings: We conducted an analysis of CD8 T-cell function and severity of symptoms by self-report questionnaires in ME/CFS, Long COVID and healthy controls. We developed a CD8 T-cell functional assay, assessing CD8 T-cell dysfunction by intracellular cytokine staining (ICS) in a group of ME/CFS (n = 12) and Long COVID patients (n = 8), comparing to healthy controls (HC) with similar age and sex (n = 10). Magnet-enriched fresh CD8 T-cells in both patient groups had a significantly diminished capacity to produce both cytokines, IFNγ or TNFα, after PMA stimulation when compared to HC. The symptom severity questionnaire showed similar symptom profiles for the two disorders. Fortuitously, through a retrospective case series, we were able to examine the ICS and questionnaire data of 4 ME/CFS and 4 Long COVID patients in conjunction with their treatment (3–15 months). In parallel with the treatment pursued electively by participants in this retrospective case series, there was an increase in CD8 T-cell IFNγ and TNFα production and a decrease in overall self-reported symptom severity score by 54%. No serious treatment-associated side effects or laboratory anomalies were noted in these patients.

Conclusions: Here, in this small study, we present two observations that appear potentially fundamental to the pathogenesis and treatment of Long COVID and ME/CFS. The first is that both disorders appear to be characterized by dysfunctional CD8 T-cells with severe deficiencies in their abilities to produce IFNγ and TNFα. The second is that in a small retrospective Long COVID and ME/CFS case series, this immune dysfunction and patient health improved in parallel with treatment with an immunomodulatory, antioxidant pharmacological treatment with anticipated anti-pathogen activity. This work provides evidence of the potential utility of a biomarker, CD8 T-cell dysfunction, and suggests the potential for benefit from a new nebulized antioxidant/anti-pathogen treatment. These immune biomarker data may help build capacity for improved diagnosis and tracking of treatment outcomes during clinical trials for both Long COVID and ME/CFS while providing clues to new treatment avenues that suggest potential efficacy for both conditions.

Source: Gil, A., Hoag, G.E., Salerno, J.P., Hornig, M., Klimas, N., Selin, L.K. Identification of CD8 T-cell dysfunction associated with symptoms in myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS) and Long COVID and treatment with a nebulized antioxidant/antipathogen agent in a retrospective case series. Brain, Behavior, & Immunity – Health (2024), doi: https://doi.org/10.1016/j.bbih.2023.100720 https://www.sciencedirect.com/science/article/pii/S2666354623001345 (Full text)