Kynurenine serves as useful biomarker in acute, Long- and Post-COVID-19 diagnostics

Abstract:

Introduction: In patients with SARS-CoV-2, innate immunity is playing a central role, depicted by hyperinflammation and longer lasting inflammatory response. Reliable inflammatory markers that cover both acute and long-lasting COVID-19 monitoring are still lacking. Thus, we investigated one specific inflammatory marker involved as one key player of the immune system, kynurenine (Kyn), and its use for diagnosis/detection of the Long-/Post-COVID syndrome in comparison to currently used markers in both serum and saliva samples.

Material and methods: The study compromised in total 151 inpatients with a SARS-CoV-2 infection hospitalized between 03/2020 and 09/2021. The group NC (normal controls) included blood bank donors (n=302, 144f/158m, mean age 47.1 ± 18.3 years (range 18-75)). Two further groups were generated based on Group A (n=85, 27f/58m, mean age 63.1 ± 18.3 years (range 19-90), acute admission to the hospital) and Group B (n=66, 22f/44m, mean age 66.6 ± 17.6 years (range 17-90), admitted either for weaning or for rehabilitation period due to Long-COVID symptoms/syndrome). Plasma concentrations of Kyn, C-Reactive Protein (CRP) and interleukin-6 (IL-6) were measured on admission. In Group B we determined Kyn 4 weeks after the negative PCR-test. In a subset of patients (n=11) concentrations of Kyn and CRP were measured in sera and saliva two, three and four months after dismission. We identified 12 patients with Post-COVID symptoms >20 weeks with still significant elevated Kyn-levels.

Results: Mean values for NC used as reference were 2.79 ± 0.61 µM, range 1.2-4.1 µM. On admission, patients showed significantly higher concentrations of Kyn compared to NC (p-values < 0.001). Kyn significantly correlated with IL-6 peak-values (r=0.411; p-values <0.001) and CRP (r=0.488, p-values<0.001). Kyn values in Group B (Long-/Post-COVID) showed still significant higher values (8.77 ± 1.72 µM, range 5.5-16.6 µM), whereas CRP values in Group B were in the normal range.

Conclusion: Serum and saliva Kyn are reflecting the acute and long-term pathophysiology of the SARS-CoV-2 disease concerning the innate immune response and thus may serve a useful biomarker for diagnosis and monitoring both Long- and Post-COVID syndrome and its therapy.

Source: Bizjak DA, Stangl M, Börner N, Bösch F, Durner J, Drunin G, Buhl JL, Abendroth D. Kynurenine serves as useful biomarker in acute, Long- and Post-COVID-19 diagnostics. Front Immunol. 2022 Sep 23;13:1004545. doi: 10.3389/fimmu.2022.1004545. PMID: 36211365; PMCID: PMC9537769. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9537769/ (Full text)

Plasma cytokine levels reveal deficiencies in IL-8 and gamma interferon in Long-COVID

Abstract:

Up to half of individuals who contract SARS-CoV-2 develop symptoms of long-COVID approximately three months after initial infection. These symptoms are highly variable, and the mechanisms inducing them are yet to be understood.

We compared plasma cytokine levels from individuals with long-COVID to healthy individuals and found that those with long-COVID had 100% reductions in circulating levels of interferon gamma (IFNγ) and interleukin-8 (IL-8). Additionally, we found significant reductions in levels of IL-6, IL-2, IL-17, IL-13, and IL-4 in individuals with long-COVID.

We propose immune exhaustion as the driver of long-COVID, with the complete absence of IFNγ and IL-8 preventing the lungs and other organs from healing after acute infection, and reducing the ability to fight off subsequent infections, both contributing to the myriad of symptoms suffered by those with long-COVID.

Source: Williams ESCP, Martins TB, Hill HR, Coiras M, Shah KS, Planelles V, Spivak AM. Plasma cytokine levels reveal deficiencies in IL-8 and gamma interferon in Long-COVID. medRxiv [Preprint]. 2022 Oct 5:2022.10.03.22280661. doi: 10.1101/2022.10.03.22280661. PMID: 36238724; PMCID: PMC9558442. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9558442/ (Full text)

Pathophysiology of Post-COVID syndromes: a new perspective

Abstract:

Most COVID-19 patients recovered with low mortality; however, some patients experienced long-term symptoms described as “long-COVID” or “Post-COVID syndrome” (PCS). Patients may have persisting symptoms for weeks after acute SARS-CoV-2 infection, including dyspnea, fatigue, myalgia, insomnia, cognitive and olfactory disorders. These symptoms may last for months in some patients.

PCS may progress in association with the development of mast cell activation syndrome (MCAS), which is a distinct kind of mast cell activation disorder, characterized by hyper-activation of mast cells with inappropriate and excessive release of chemical mediators. COVID-19 survivors, mainly women, and patients with persistent severe fatigue for 10 weeks after recovery with a history of neuropsychiatric disorders are more prone to develop PCS. High D-dimer levels and blood urea nitrogen were observed to be risk factors associated with pulmonary dysfunction in COVID-19 survivors 3 months post-hospital discharge with the development of PCS. PCS has systemic manifestations that resolve with time with no further complications. However, the final outcomes of PCS are chiefly unknown.

Persistence of inflammatory reactions, autoimmune mimicry, and reactivation of pathogens together with host microbiome alterations may contribute to the development of PCS. The deregulated release of inflammatory mediators in MCAS produces extraordinary symptoms in patients with PCS. The development of MCAS during the course of SARS-CoV-2 infection is correlated to COVID-19 severity and the development of PCS. Therefore, MCAS is treated by antihistamines, inhibition of synthesis of mediators, inhibition of mediator release, and inhibition of degranulation of mast cells.

Source: Batiha, G.ES., Al-kuraishy, H.M., Al-Gareeb, A.I. et al. Pathophysiology of Post-COVID syndromes: a new perspective. Virol J 19, 158 (2022). https://doi.org/10.1186/s12985-022-01891-2  https://virologyj.biomedcentral.com/articles/10.1186/s12985-022-01891-2 (Full text)

Sleep symptoms are essential features of long-COVID – Comparing healthy controls with COVID-19 cases of different severity in the international COVID sleep study (ICOSS-II)

Abstract:

Many people report suffering from post-acute sequelae of COVID-19 or “long-COVID”, but there are still open questions on what actually constitutes long-COVID and how prevalent it is. The current definition of post-acute sequelae of COVID-19 is based on voting using the Delphi-method by the WHO post-COVID-19 working group. It emphasizes long-lasting fatigue, shortness of breath and cognitive dysfunction as the core symptoms of post-acute sequelae of COVID-19.

In this international survey study consisting of 13,628 subjects aged 18-99 years from 16 countries of Asia, Europe, North America and South America (May-Dec 2021), we show that post-acute sequelae of COVID-19 symptoms were more prevalent amongst the more severe COVID-19 cases, i.e. those requiring hospitalisation for COVID-19. We also found that long-lasting sleep symptoms are at the core of post-acute sequelae of COVID-19 and associate with the COVID-19 severity when COVID-19 cases are compared with COVID-negative cases.

Specifically, fatigue (61.3%), insomnia symptoms (49.6%) and excessive daytime sleepiness (35.8%) were highly prevalent amongst respondents reporting long-lasting symptoms after hospitalisation for COVID-19. Understanding the importance of sleep-related symptoms in post-acute sequelae of COVID-19 has a clinical relevance when diagnosing and treating long-COVID.

Source: Merikanto I, Dauvilliers Y, Chung F, Wing YK, de Gennaro L, Holzinger B, Bjorvatn B, Morin CM, Penzel T, Benedict C, Koscec Bjelajac A, Chan NY, Espie CA, Hrubos-Strøm H, Inoue Y, Korman M, Landtblom AM, Léger D, Matsui K, Mota-Rolim S, Nadorff MR, Plazzi G, Reis C, Yordanova J, Partinen M. Sleep symptoms are essential features of long-COVID – Comparing healthy controls with COVID-19 cases of different severity in the international COVID sleep study (ICOSS-II). J Sleep Res. 2022 Oct 8:e13754. doi: 10.1111/jsr.13754. Epub ahead of print. PMID: 36208038. https://onlinelibrary.wiley.com/doi/10.1111/jsr.13754 (Full text)

Grief in Chronic Illness: A Case Study of CFS/ME

Abstract:

This paper points to a more expansive conception of grief by arguing that the losses of illness can be genuine objects of grief.

I argue for this by illuminating underappreciated structural features of typical grief — that is, grief over a bereavement — which are shared but under-recognized. I offer a common chronic illness, chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), as a striking case study.

I then use this analysis to highlight some clinical challenges that arise should this claim receive uptake in clinical practice.

Extant literature on CFS/ME tells us that rates of comorbid depression are atypically high. If one accepts that people with CFS/ ME can grieve over losses associated with the condition, and that grief can be easily mistaken for depression in this context, this might suggest that rates of comorbid depression are inflated.

I show, however, that the challenge of distinguishing between healthy and pathological grief arises in its place, and is just as tricky to solve.

Source: Byrne, Eleanor Alexandra. Grief in Chronic Illness: A Case Study of CFS/ME. Journal of Consciousness Studies, Volume 29, Numbers 9-10, September 2022, pp. 175-200(26). https://www.ingentaconnect.com/contentone/imp/jcs/2022/00000029/f0020009/art00009

Symptomatology and microbiology of the gastrointestinal tract in post-COVID conditions

Abstract:

Post-COVID conditions, also known as post-acute sequelae of SARS-CoV-2 (PASC), refer to the persistence of symptoms in COVID-19 long-haulers. Various manifestations of post-COVID conditions are general symptoms and/or manifestations of damage in multiple organs. Besides, SARS-CoV-2 can involve the gastrointestinal tract, resulting in sequelae such as diarrhea, abdominal pain, nausea, anorexia, vomiting, constipation, abdominal distension, acid reflux, and/or gastrointestinal bleeding.
Previous investigations point to SARS-CoV-2 entry into enterocytes enhances by the angiotensin-converting enzyme 2 (ACE2) receptors. Interestingly, ACE2 receptors are abundantly expressed in the gut, implying infection with SARS-CoV-2 might occur through this route as well as in the respiratory tract. According to mounting evidence, SARS-CoV-2 RNA has been identified in fecal specimens of patients with COVID-19 during and beyond the acute phase.
In addition, studies have shown gut microbiome composition is altered in patients with PASC, hence, another putative mechanism linked to gastrointestinal symptoms is gut dysbiosis. The presence of the gut-lung axis in COVID-19 might have major implications for disease pathogenesis and treatment.
This review discussed the prevalence of gastrointestinal symptoms and pathophysiology underlying possible infection of the gut in patients with PASC. Also, SARS-COV-2 induced NLRP3 inflammasome-dependent inflammatory pathways are briefly addressed.
Source: Norouzi Masir M, Shirvaliloo M. Symptomatology and microbiology of the gastrointestinal tract in post-COVID conditions. JGH Open : an Open Access Journal of Gastroenterology and Hepatology. 2022 Aug. DOI: 10.1002/jgh3.12811. PMID: 36247234; PMCID: PMC9538198. https://europepmc.org/article/pmc/pmc9538198 (Full text)

Saliva antibody-fingerprint of reactivated latent viruses after mild/asymptomatic COVID-19 is unique in patients with myalgic-encephalomyelitis/chronic fatigue syndrome

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic disease considered to be triggered by viral infections in a majority of cases. Symptoms overlap largely with those of post-acute sequelae of COVID-19/long-COVID implying common pathogenetic mechanisms. SARS-CoV-2 infection is risk factor for sustained latent virus reactivation that may account for the symptoms of post-viral fatigue syndromes. The aim of this study was first to investigate whether patients with ME/CFS and healthy donors (HDs) differed in their antibody response to mild/asymptomatic SARS-CoV-2 infection. Secondly, to analyze whether COVID-19 imposes latent virus reactivation in the cohorts.

Methods: Anti-SARS-CoV-2 antibodies were analyzed in plasma and saliva from non-vaccinated ME/CFS (n=95) and HDs (n=110) using soluble multiplex immunoassay. Reactivation of human herpesviruses 1-6 (HSV1, HSV2, VZV, EBV, CMV, HHV6), and human endogenous retrovirus K (HERV-K) was detected by anti-viral antibody fingerprints in saliva.

Results: At 3-6 months after mild/asymptomatic SARS-CoV-2 infection, virus-specific antibodies in saliva were substantially induced signifying a strong reactivation of latent viruses (EBV, HHV6 and HERV-K) in both cohorts. In patients with ME/CFS, antibody responses were significantly stronger, in particular EBV-encoded nuclear antigen-1 (EBNA1) IgG were elevated in patients with ME/CFS, but not in HDs. EBV-VCA IgG was also elevated at baseline prior to SARS-infection in patients compared to HDs.

Conclusion: Our results denote an altered and chronically aroused anti-viral profile against latent viruses in ME/CFS. SARS-CoV-2 infection even in its mild/asymptomatic form is a potent trigger for reactivation of latent herpesviruses (EBV, HHV6) and endogenous retroviruses (HERV-K), as detected by antibody fingerprints locally in the oral mucosa (saliva samples). This has not been shown before because the antibody elevation is not detected systemically in the circulation/plasma.

Source: Apostolou Eirini, Rizwan Muhammad, Moustardas Petros, Sjögren Per, Bertilson Bo Christer, Bragée Björn, Polo Olli, Rosén Anders. Saliva antibody-fingerprint of reactivated latent viruses after mild/asymptomatic COVID-19 is unique in patients with myalgic-encephalomyelitis/chronic fatigue syndrome. Frontiers in Immunology, Vol 13, 2022. https://www.frontiersin.org/articles/10.3389/fimmu.2022.949787/full (Full text)

Even mild COVID-19 may have long-term brain impacts

Research presented at the Alzheimer’s Association International Conference suggests even mild cases of COVID-19 may be associated with cognitive deficits months after recovery.

One Argentinian study of 234 seniors who previously had COVID-19 found that more than half showed some degree of cognitive impairment months later. One in three had severe “dementia-like” impairments in memory, attention and executive function — a much higher proportion than the 5%–8% of seniors in the general population who have dementia at a given time.

“This could be the start of a dementia-related epidemic fueled by this latest coronavirus,” stated presenting author Dr. Gabriel de Erausquin of the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio. Researchers will follow the study participants over the next three to five years to see if these problems resolve or worsen.

The study didn’t look at participants’ cognitive performance prior to infection. However, those who lost their sense of smell while sick with COVID-19 tended to have more severe cognitive impairments months later, even if their other symptoms had been mild. According to de Erausquin, “once the virus has affected the olfactory bulb and caused effects there — changes that we can see with imaging — then other places in the brain that are connected to it also become abnormal, either in function or structure or both.”

Other research presented linked SARS-CoV-2 infection with an uptick in biomarkers of brain injury, neuroinflammation and Alzheimer disease. One American study of 310 patients with COVID-19 found that those with new neurological symptoms had higher levels of t-tau, NfL, GFAP, pTau-181, and UCH-L1 in their blood, as well as indicators of inflammation such as C-reactive protein, compared to patients without neurological symptoms. “These findings suggest patients who had COVID-19 may have an acceleration of Alzheimer-related symptoms and pathology,” according to presenting author Dr. Thomas Wisniewski of the New York University Grossman School of Medicine.

Earlier this year, de Erausquin and others reported that brain inflammation, stroke and other common complications of viral infections have longstanding links with neurodegenerative disorders. “Therefore, it seems likely to expect that COVID-19-related cardiovascular and cerebrovascular disease will also contribute to a higher longterm risk of cognitive decline and dementia in recovered individuals.”

Several recent studies have documented cognitive deficits post-COVID but like the research presented at the Alzheimer’s Association conference, data on patients’ performance before infection are lacking.

One British study of 81 337 people in EClinicalMedicine found that those who previously had COVID-19 tended to score lower on measures of intelligence, reasoning, problem-solving and planning than people who were never infected.

“These results accord with reports of long-COVID, where ‘brain fog,’ trouble concentrating and difficulty finding the correct words are common,” according to the authors. People who had been hospitalized and put on ventilators had the greatest impairments, but even those who had relatively mild symptoms showed some deficit.

In another study of 57 Americans receiving inpatient rehabilitation after hospitalization for COVID-19, four in five had mild to severe cognitive impairments. More than half had deficits in working memory, while two in five had impaired processing speed, divided attention, and trouble switching between mental tasks.

Similar deficits have also been noted in patients after recovery from other coronaviruses. A 2020 systematic review and meta-analysis found that delirium was common in the acute stage of severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and COVID-19. Following up with patients six weeks to 39 months later, more than 15% reported sleep disorders, mood swings, trouble concentrating, impaired memory and other mental challenges.

Based on this growing body of evidence, British researchers warned in March that health systems will likely see an “influx of patients with psychiatric and cognitive problems who were otherwise healthy prior to COVID-19.” They urged doctors to consider detailed cognitive evaluations for anyone reporting new neurological symptoms after infection with SARS-CoV-2.

In the meantime, the Alzheimer’s Association has formed an international consortium to study the long-term effects of COVID-19 on the brain.

“These new data point to disturbing trends showing COVID-19 infections leading to lasting cognitive impairment and even Alzheimer’s symptoms,” stated Heather Snyder of the Alzheimer’s Association. “It is imperative that we continue to study what this virus is doing to our bodies and brains.”

Source: Duong D. Even mild COVID-19 may have long-term brain impacts. CMAJ. 2021 Aug 30;193(34):E1360-E1361. doi: 10.1503/cmaj.1095958. PMID: 34462298; PMCID: PMC8432319.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8432319/ (Full text)

Factors Influencing the Prognosis of Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a long-term debilitating multisystem condition with poor prognosis. Studies that examined predictors of ME/CFS outcomes yielded contradictory results. We aimed to explore epidemiological and clinical prognostic factors of ME/CFS using operationalized criteria for recovery/improvement.
Adult ME/CFS patients who attended the Internal Medicine Department of Angers University Hospital, Angers, France between October 2011 and December 2019, and were followed up until December 2020, were included retrospectively. Their medical records were reviewed for data collection. Patients were classified into two groups according to the presence or absence of recovery/improvement (R/I) and compared for epidemiological characteristics, fatigue features, post-exertional malaise severity, clinical manifestations, and comorbidities.
The subgroups of recovered and significantly improved patients were then compared. 168 patients were included. Recovery and improvement rates were 8.3% and 4.8%, respectively. Older age at disease onset was associated with R/I (OR 1.06 [95% CI 1.007–1.110] (p = 0.028)), while diagnostic delay was inversely associated with R/I (OR 0.98 [95% CI 0.964–0.996] (p = 0.036)). The study findings confirmed the poor prognosis of ME/CFS and the deleterious effect of diagnostic delay on disease progression. Interestingly, being older at disease onset was associated with better outcomes, which offers hope to patients for recovery/improvement even at an advanced age.
Source: Ghali A, Lacout C, Fortrat J-O, Depres K, Ghali M, Lavigne C. Factors Influencing the Prognosis of Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Diagnostics. 2022; 12(10):2540. https://doi.org/10.3390/diagnostics12102540  https://www.mdpi.com/2075-4418/12/10/2540 (Full text available as PDF file)

Endothelial dysfunction in COVID-19: an overview of evidence, biomarkers, mechanisms and potential therapies

Abstract:

The fight against coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection is still raging. However, the pathophysiology of acute and post-acute manifestations of COVID-19 (long COVID-19) is understudied. Endothelial cells are sentinels lining the innermost layer of blood vessel that gatekeep micro- and macro-vascular health by sensing pathogen/danger signals and secreting vasoactive molecules. SARS-CoV-2 infection primarily affects the pulmonary system, but accumulating evidence suggests that it also affects the pan-vasculature in the extrapulmonary systems by directly (via virus infection) or indirectly (via cytokine storm), causing endothelial dysfunction (endotheliitis, endothelialitis and endotheliopathy) and multi-organ injury.

Mounting evidence suggests that SARS-CoV-2 infection leads to multiple instances of endothelial dysfunction, including reduced nitric oxide (NO) bioavailability, oxidative stress, endothelial injury, glycocalyx/barrier disruption, hyperpermeability, inflammation/leukocyte adhesion, senescence, endothelial-to-mesenchymal transition (EndoMT), hypercoagulability, thrombosis and many others. Thus, COVID-19 is deemed as a (micro)vascular and endothelial disease. Of translational relevance, several candidate drugs which are endothelial protective have been shown to improve clinical manifestations of COVID-19 patients.

The purpose of this review is to provide a latest summary of biomarkers associated with endothelial cell activation in COVID-19 and offer mechanistic insights into the molecular basis of endothelial activation/dysfunction in macro- and micro-vasculature of COVID-19 patients. We envisage further development of cellular models and suitable animal models mimicking endothelial dysfunction aspect of COVID-19 being able to accelerate the discovery of new drugs targeting endothelial dysfunction in pan-vasculature from COVID-19 patients.

Source: Xu, Sw., Ilyas, I. & Weng, Jp. Endothelial dysfunction in COVID-19: an overview of evidence, biomarkers, mechanisms and potential therapies. Acta Pharmacol Sin (2022). https://doi.org/10.1038/s41401-022-00998-0 https://www.nature.com/articles/s41401-022-00998-0 (Full text)