Microbiome and intestinal pathophysiology in post-acute sequelae of COVID-19

Abstract:

Long COVID, also known for post-acute sequelae of COVID-19, describes the people who have the signs and symptoms that continue or develop after the acute COVID-19 phase. Long COVID patients suffer from an inflammation or host responses towards the virus approximately 4 weeks after initial infection with the SARS CoV-2 virus and continue for an uncharacterized duration.

Anyone infected with COVID-19 before could experience long-COVID conditions, including the patients who were infected with SARS CoV-2 virus confirmed by tests and those who never knew they had an infection early. People with long COVID may experience health problems from different types and combinations of symptoms over time, such as fatigue, dyspnea, cognitive impairments, and gastrointestinal (GI) symptoms (e.g., nausea, vomiting, diarrhea, decreased or loss of appetite, abdominal pain, and dysgeusia). The critical role of the microbiome in these GI symptoms and long COVID were reported in clinical patients and experimental models.

Here, we provide an overall view of the critical role of the GI tract and microbiome in the development of long COVID, including the clinical GI symptoms in patients, dysbiosis, viral-microbiome interactions, barrier function, and inflammatory bowel disease patients with long COVID. We highlight the potential mechanisms and possible treatment based on GI health and microbiome. Finally, we discuss challenges and future direction in the long COVID clinic and research.

Source: Zhang J, Zhang Y, Xia Y, Sun J. Microbiome and intestinal pathophysiology in post-acute sequelae of COVID-19. Genes Dis. 2023 Jun 19. doi: 10.1016/j.gendis.2023.03.034. Epub ahead of print. PMID: 37362775; PMCID: PMC10278891. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10278891/ (Full text)

In vivo inhibition of nuclear ACE2 translocation protects against SARS-CoV-2 replication and lung damage through epigenetic imprinting

Abstract:

In vitro, ACE2 translocates to the nucleus to induce SARS-CoV-2 replication. Here, using digital spatial profiling of lung tissues from SARS-CoV-2-infected golden Syrian hamsters, we show that a specific and selective peptide inhibitor of nuclear ACE2 (NACE2i) inhibits viral replication two days after SARS-CoV-2 infection. Moreover, the peptide also prevents inflammation and macrophage infiltration, and increases NK cell infiltration in bronchioles.

NACE2i treatment increases the levels of the active histone mark, H3K27ac, restores host translation in infected hamster bronchiolar cells, and leads to an enrichment in methylated ACE2 in hamster bronchioles and lung macrophages, a signature associated with virus protection. In addition, ACE2 methylation is increased in myeloid cells from vaccinated patients and associated with reduced SARS-CoV-2 spike protein expression in monocytes from individuals who have recovered from infection.

This protective epigenetic scarring of ACE2 is associated with a reduced latent viral reservoir in monocytes/macrophages and enhanced immune protection against SARS-CoV-2. Nuclear ACE2 may represent a therapeutic target independent of the variant and strain of viruses that use the ACE2 receptor for host cell entry.

Source: Tu WJ, Melino M, Dunn J, McCuaig RD, Bielefeldt-Ohmann H, Tsimbalyuk S, Forwood JK, Ahuja T, Vandermeide J, Tan X, Tran M, Nguyen Q, Zhang L, Nam A, Pan L, Liang Y, Smith C, Lineburg K, Nguyen TH, Sng JDJ, Tong ZWM, Chew KY, Short KR, Le Grand R, Seddiki N, Rao S. In vivo inhibition of nuclear ACE2 translocation protects against SARS-CoV-2 replication and lung damage through epigenetic imprinting. Nat Commun. 2023 Jun 27;14(1):3680. doi: 10.1038/s41467-023-39341-4. PMID: 37369668; PMCID: PMC10300102. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10300102/ (Full text)

Interventions to support mental health in people with long COVID: a scoping review

Abstract:

Introduction: Long COVID (LC) is a multisystem disease with symptoms lasting weeks or months beyond the acute COVID-19 infection. Several manifestations are reported by people with LC, including effects on mental health, with varying degrees of psychological distress and disturbances to daily activities. Research conducted to identify effective interventions to support mental health among people with LC has been limited by the breadth and scope of studies.

Aim: This review aims to identify interventions being tested to support mental health of people with LC.

Methods: A scoping review was conducted by searching five databases for articles published between January 2020 and early October 2022 to identify research evaluating interventions focused on improving mental health symptoms associated with LC. Results from all sources were checked for eligibility by two reviewers, and agreements were resolved by discussion. Gray literature and reference list of included studies and relevant reviews were scrutinised to identify any additional studies. Data extraction was conducted by one reviewer and checked by another reviewer for accuracy.

Results: Of the 940 studies identified, 17 were included, the design of which varied but included mainly case studies (n = 6) and clinical trials (n = 5). Several interventions were described, ranging from single interventions (e.g., pharmacologic) to more holistic, comprehensive suites of services (pharmacologic and non-pharmacologic). Several mental health outcomes were measured, mostly anxiety and depression. All included studies were reported to be associated with improvements in participants’ mental health outcomes.

Conclusion: This scoping review identified studies reporting on a variety of interventions to support mental health among people with LC. Although positive changes were reported by all studies, some were case studies and thus their findings must be interpreted with caution. There is a need for more research to be conducted to identify the impact of interventions on mental health of people with LC.

Source: Al-Jabr H, Hawke LD, Thompson DR, Clifton A, Shenton M, Castle DJ, Ski CF. Interventions to support mental health in people with long COVID: a scoping review. BMC Public Health. 2023 Jun 20;23(1):1186. doi: 10.1186/s12889-023-16079-8. PMID: 37340400; PMCID: PMC10280822. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10280822/ (Full text)

Pre-pandemic activity on a myalgic encephalomyelitis/chronic fatigue syndrome support forum is highly associated with later activity on a long COVID support forum for a variety of reasons: a mixed methods study.

Abstract:

Encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID share some clinical and social characteristics. We predicted that this would lead to an increased interaction between pre-pandemic members of a ME/CFS online support community and a long COVID community.

We performed a mixed-methods retrospective observational study of the Reddit activity of 7,544 users active on Reddit’s long COVID forum. From among 1600 forums, pre-pandemic activity specifically on a ME/CFS forum is the top predictor of later participation on the long COVID forum versus an acute COVID support forum.

In the qualitative portion, motives for this co-participation included seeking mutual support and dual identification with both conditions. Some of this effect may be explained by pre-existing ME/CFS possibly being a risk factor for long COVID and/or SARS-CoV-2 infection being a cause of ME/CFS relapse. The high rate of ME/CFS patients seeking mutual support on a long COVID forum speaks to the long-suffering experience of these patients not feeling heard or respected, and the hope of some ME/CFS patients to gain legitimacy through the public’s growing recognition of long COVID.

Source: William U Meyerson, Rick H Hoyle. Pre-pandemic activity on a myalgic encephalomyelitis/chronic fatigue syndrome support forum is highly associated with later activity on a long COVID support forum for a variety of reasons: a mixed methods study. medRxiv 2023.06.30.23292087; doi: https://doi.org/10.1101/2023.06.30.23292087 https://www.medrxiv.org/content/10.1101/2023.06.30.23292087v1 9 (Full text available as PDF file)

High incidence of autonomic dysfunction and postural orthostatic tachycardia syndrome in patients with long-COVID: Implications for management and healthcare planning

Abstract:

Background: Autonomic dysfunction including postural orthostatic tachycardia syndrome (POTS) has been reported in individuals with post-acute sequelae of Covid-19 (PASC). However, the degree of dysautonomia in PASC has not been compared to those with POTS and healthy controls.

Methods: All participants were prospectively enrolled between 5th August 2021 and 31st October 2022. Autonomic testing included beat-to-beat hemodynamic monitoring to assess respiratory sinus arrhythmia, Valsalva ratio and orthostatic changes during a 10-minute active standing test as well as Sudomotor assessment. The Composite Autonomic Symptom Score (COMPASS-31) was used to assess symptoms and the Euroquol 5-Dimension survey (EQ-5D-5L) was used to assess health-related quality of life (HrQoL) measures.

Results: A total of 99 participants (n=33 PASC, n=33 POTS and n=33 healthy controls; median age 32 [18], 85.9% females) were included. Compared to healthy controls, the PASC and POTS cohorts demonstrated significantly reduced respiratory sinus arrhythmia (p<0.001), greater heart rate increase during 10-minute active standing test (p<0.001), greater burden of autonomic dysfunction evidenced by higher COMPASS-31 scores across all subdomains (all p<0.001) and poor HrQoL across all EQ-5D-5L domains (all p<0.001), lower median EQ-VAS (p<0.001) and lower utility scores (p<0.001). The majority (79%) of those with PASC met the internationally established criteria for POTS.

Conclusion: The prevalence of autonomic symptomology or POTS was high in those with PASC, leading to poor HrQoL and high health disutility. Autonomic testing should be routinely undertaken in those with PASC to aid diagnosis and direct appropriate management to improve health outcomes.

Trial registration: ANZCTR 12621000476831.

Source: Seeley MC, Gallagher C, Ong E, Langdon A, Chieng J, Bailey D, Page A, Lim HS, Lau DH. High incidence of autonomic dysfunction and postural orthostatic tachycardia syndrome in patients with long-COVID: Implications for management and healthcare planning. Am J Med. 2023 Jun 28:S0002-9343(23)00402-3. doi: 10.1016/j.amjmed.2023.06.010. Epub ahead of print. PMID: 37391116. https://www.amjmed.com/article/S0002-9343(23)00402-3/fulltext (Full text)

Research progress on central mechanism of acupuncture treatment for chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome is a neurological disorder characterized by extreme fatigue that lasts for a long time and doesn’t alleviate with rest. The number of the cases has been increasing during the era of COVID-19 pandemic.

Acupuncture may have some effect on chronic fatigue syndrome, but its mechanism remains unclear. This article was to summarize the specific manifestations of abnormal central mechanism in patients with chronic fatigue syndrome through laboratory tests and neuroimaging.

It was found from the laboratory evaluation that there were changes in the structure of the frontal cortex, thalamus and other brain tissues; factors, including IFN-α and IL-10 in cerebrospinal fluid were found abnormal; results of oxidative and nitrosative stress and changes in neurobiochemical substances, e.g. hypothalamus hormone levels and neurotransmitter concentrations, were observed.

With magnetic resonance imaging and positron emission tomography, it was shown that the partial brain of persons with chronic fatigue syndrome had morphological changes with diminished grey matter and white; changes in cerebral blood flow velocity caused by decreased perfusion and functional activity with abnormal connectivity in brain were detected.

In addition, there was significant decrease in glucose metabolism accompanied with neuroinflammatory response; metabolic disorders of serotonergic, cholinergic, glutamatergic and γ-aminobutyric acid energy neurotransmitters were also discovered.

The regulatory effect of acupuncture on the above central neurological abnormalities in chronic fatigue syndrome model animals was elaborated, and the direction for further research was analyzed in order to provide ideas for further research on the central mechanism of acupuncture treatment for chronic fatigue syndrome.

Source: Li BB, Feng CW, Qu YY, Sun ZR, Chen T, Wang YL, Wang QY, Lu J, Shao YY, Yang TS. Research progress on central mechanism of acupuncture treatment for chronic fatigue syndrome. World J Acupunct Moxibustion.  doi: 10.1016/j.wjam.2023.03.002 [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10061266/ (Full text)

Symptoms and signs of dry eye in US veterans with Myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Purpose: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is clinically defined as persistent and unexplainable post-exertional fatigue and can present with a wide range of cognitive, immunological, endocrinological, and autonomic symptoms. A notable feature of ME/CFS is its comorbidity with pain in multiple compartments. In this study, we examine ocular manifestations associated with ME/CFS, with a focus on ocular surface pain complaints.

Methods: We recruited 124 United States veterans and profiled them for symptoms and signs of dry eye (DE). Individuals were grouped by the presence (n=42) and absence (n=82) of ME/CFS.

Results: The mean age of the population was 55.49 ± 4.61 years, 88.7% of participants identified as male, 58.1% as White, and 39.5% as Hispanic. Demographics, medical comorbidities, and medication use were similar between groups except for depression (57.1% vs. 29.6%, p=0.003), and history of traumatic brain injury (9.5% vs. 1.2%, p=0.03) which were more prevalent in the ME/CFS group. Individuals with ME/CFS reported higher ocular surface pain complaints, both through DE specific questionnaires (Ocular Surface Disease Index, OSDI; 5-Item DE Questionnaire, DEQ-5) and pain specific questionnaires (Neuropathic Pain Symptom Inventory, modified for the Eye, NPSI-E; Numerical rating scale, NRS) (Table 1). Ocular surface parameters were similar between groups, except for persistent pain after topical anesthesia which was more frequent in the ME/CFS group (Table 2).

Conclusions: Individuals who met criteria for ME/CFS had more severe ocular surface pain, but similar signs of DE, compared to controls. This suggests that nerve, and not tear, abnormalities contribute to ocular surface pain in ME/CFS.

Source: Victor Sanchez; Colin Kim; Kimberly Cabrera; Elyana Vittoria Tessa Locatelli; Molly Johnson; Anat Galor. Symptoms and signs of dry eye in US veterans with Myalgic encephalomyelitis/chronic fatigue syndrome. Investigative Ophthalmology & Visual Science June 2023, Vol.64, 3978. https://iovs.arvojournals.org/article.aspx?articleid=2790532 

A Thesis on Immune Differences in Chronic Fatigue Syndrome, Fibromyalgia and Healthy Controls

Abstract:

Background: Chronic Fatigue Syndrome (CFS) and Fibromyalgia (FM) are debilitating disorders that significantly affect the daily lives of those suffering from them, as well as their loved ones. Both conditions have overlapping clinical features that resemble inflammatory disorders, and overlapping symptoms, such as depression, suggest central nervous system (CNS) involvement. The role of the immune system’s soluble messengers in the pathogenesis of CFS and FM has been under investigation, but so far the results are inconclusive. In addition, there is growing evidence that the kynurenine pathway is involved in the pathology of diseases related to the CNS, yet the role of each metabolite is not clear. The relationship between kynurenine metabolism and CFS and FM has not been extensively explored. Few studies have simultaneously examined the immunological status in both CFS and FM, making this thesis the first to comprehensively evaluate the potential distinct immunological differences between the two disorders.

Objective: The objective of this study was to compare the CFS and FM with healthy controls, regarding the levels of several soluble blood markers related to the immune system. The markers chosen were:

  • The inflammatory marker high-sensitive CRP (hsCRP)
  • The following cytokines and chemokines: Interferon (IFN)-γ, Interleukin (IL)-1β, IL1ra, IL-4, IL-6, IL-8, IL-10, IL-17, Interferon gamma-induced protein (IP)-10, Monocyte Chemoattractant Protein (MCP)-1, Transforming Growth Factor (TGF)-β1, TGF-β2, TGF-β3 and Tumour Necrosis Factor (TNF)-α
  • The metabolites and their ratios of the kynurenine pathway: Tryptophan (Try), kynurenine (Kyn), kynurenic acid (KA), 3-hydroxykykynurenine (HK), anthranilic acid (AA), xanthurenic acid (XA), 3-hydroxyanthranilic acid (HAA), quinolinic acid (QA) and picolinic acid (Pic).

Method: The population consisted of three groups: CFS patients (n = 49), FM patients (n = 58), and healthy controls (n = 54). All participants were females aged 18–60. Patients were recruited from a specialised university hospital clinic and controls were recruited by advertisement among the staff and students at the hospital and university.

Plasma levels of hsCRP were analysed at the hospital. The cytokines and chemokines IFN-γ, IL-1β, IL-1ra, xii IL-4, IL-6, IL-8, IL-10, IL-17, IP-10, MCP-1, TGF-β1, TGF-β2, TGF-β3, and TNF-α were analysed by multiplex. Kynurenine metabolites were analysed by LC-MS/MS.

Linear regression models of log-transformed data for hsCRP and the kynurenine metabolites were conducted for comparison of the three groups CFS, FM and controls. The Kruskal-Wallis test was used to analyse differences of cytokines between the three groups. Main findings were controlled for age, body mass index (BMI), and symptoms of anxiety and depression.

Results: hsCRP levels were significantly higher for both the CFS and FM groups compared to healthy controls when adjusting for age and BMI (p = .006). There was no difference between the two patient groups. Level of hsCRP was affected by BMI (p < .001) but not age.

MCP-1 was significantly increased in both patient groups compared to healthy controls (p < .001). IL-1β, Il-4, IL-6, TNF-α, TGF-β1, TGF-β2, TGF-β3 (all p < .001), IL-10 (p = .003) and IL17 (p = .002) all were significantly lower in the patient groups compared to healthy controls. IFN-γ was significantly lower in the FM group (p < .001). For IL-8, IP-10 and IL1ra there were no significant difference.

QA differed between CFS and FM patients (p = .036) and was related to higher levels of BMI (p = .002). The KA/QA ratio was lower for CFS patients compared to healthy controls (p = .016). The KA/HK ratio was lower for FM patients compared to healthy controls, and this lower ratio was associated with increased symptoms of pain (p = .002). The kynurenine aminotransferase II (KAT II) enzymatic activity given by XA/HK was lower for FM patients compared to healthy controls (p = .013). In addition, BMI was negatively associated with enhanced KAT II enzymatic activity (p = .039).

Symptoms of anxiety and depression were not associated with any of the immune markers studied.

Conclusion: In our material hsCRP and MCP-1 are increased in patients both with CFS and with FM, while several other cytokines are either similar or significantly lower in patients than controls. Our study also indicates associations between kynurenine metabolism and CFS and FM. Kynurenine also is associated with single symptoms such as fatigue and pain. Forthcoming studies indicating interactions and causative effects, or restoration of the inflammatory status, may place cytokines and kynurenine metabolites as a target for treatment as well as prevention of these conditions in the future.

Source: Groven, Nina. A Thesis on Immune Differences in Chronic Fatigue Syndrome, Fibromyalgia and Healthy Controls. PhD Thesis [Norwegian University of Science and Technology] https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/3072207 (Full text available as PDF file)

Neuropsychological deficits in patients with persistent COVID-19 symptoms: a systematic review and meta-analysis

Abstract:

Long-term persistent symptoms of COVID-19 affect 30-80% of patients who have recovered from the disease and may continue for a long time after the disease has been overcome. The duration of these symptoms over time might have consequences that affect different aspects of health, such as cognitive abilities.

The main objective of this systematic review and meta-analysis was to objectify the persistent COVID-19 cognitive deficits after acute phase of infection and to summarize the existing evidence. Additionally, we aimed to provide a comprehensive overview to further understand and address the consequences of this disease. Our protocol was registered in PROSPERO (CRD42021260286).

Systematic research was conducted in the Web of Science, MEDLINE, PubMed, PsycINFO, Scopus, and Google Scholar databases from January 2020 to September 2021. Twenty-five studies were included, six of which were analyzed for the meta-analysis, and consisted of 175 patients who had recovered from COVID-19 and 275 healthy individuals. Analyses of cognitive performance of post-COVID-19 patients and healthy volunteers were compared using a random-effects model.

The results showed an overall medium-high effect size (g = -.68, p = .02) with a 95% CI (-1.05 to -.31), with a significantly moderate level of heterogeneity among studies (Z = 3.58, p < .001; I2 = 63%). The results showed that individuals who had recovered from COVID-19 showed significant cognitive deficits compared to controls.

Future studies should carefully assess the long-term progression of cognitive impairments in patients with persistent COVID-19 symptoms, as well as the effectiveness of rehabilitation interventions. Nevertheless, there is an urgent need to know the profile to speed up development of prevention plans as well as specific interventions. Since more information is being obtained and more studies are being conducted on the subject, the need to examine this symptomatology multidisciplinary to achieve greater scientific evidence of its incidence and prevalence has become increasingly clear.

Source: Sobrino-Relaño S, Balboa-Bandeira Y, Peña J, Ibarretxe-Bilbao N, Zubiaurre-Elorza L, Ojeda N. Neuropsychological deficits in patients with persistent COVID-19 symptoms: a systematic review and meta-analysis. Sci Rep. 2023 Jun 26;13(1):10309. doi: 10.1038/s41598-023-37420-6. PMID: 37365191; PMCID: PMC10293265. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10293265/ (Full text)

Mild COVID-19 infection associated with post-COVID-19 condition after 3 months – a questionnaire survey

Abstract:

Introduction: The coronavirus disease 2019 (COVID-19), caused by infection with SARS-CoV-2, can lead to post-COVID-19 condition, a secondary syndrome of persistent and new post-acute symptoms, but evidence on this syndrome is still scarce.

Methods: In a questionnaire survey, residents of the city of Bremen (Germany) with verified SARS-CoV-2 infection were invited to answer questions (online questionnaire or interview) concerning symptoms experienced at the time of infection and at the time of questionnaire completion at least three months later. Main outcome of the analysis was the presence of a post-COVID-19 condition at the time of the interview, defined as the presence of at least two of three leading symptoms: fatigue, breathing difficulties, or cognitive problems.

Results: A post-COVID-19 condition was more likely to be reported if respondents had, at the time of infection, suffered from fatigue (OR 1.75; 95% CI: 1.00, 3.06), breathing difficulties (OR 4.02; 95% CI: 2.80, 5.77), cognitive symptoms (OR 2.98; 95% CI: 1.48, 6.02), or head- & bone aches (OR 2.06; 95% CI: 1.25, 3.42). The odds of developing a post-COVID-19 condition increased with the number of symptoms at infection. Females were more likely to report a post-COVID-19 condition (OR 1.54; 95% CI: 1.05, 2.24). Analyzing only non-hospitalized respondents changed results only slightly.

Conclusion: Our study adds to growing evidence that even a mild course of COVID-19 poses a risk for developing a post-COVID-19 condition. Females and those with initial symptoms including fatigue, breathing difficulties, and cognitive symptoms seem more likely to also experience post COVID-19 symptoms several months after infection.

KEY MESSAGES

Even a mild course of COVID-19 poses a risk for developing a post-COVID-19 condition.

Females seem more likely to develop a post-COVID-19 condition.

Those with initial symptoms including fatigue, breathing difficulties, and cognitive symptoms seem more likely to develop a post-COVID-19 condition.

Source: Rach S, Kühne L, Zeeb H, Ahrens W, Haug U, Pohlabeln H. Mild COVID-19 infection associated with post-COVID-19 condition after 3 months – a questionnaire survey. Ann Med. 2023 Dec;55(1):2226907. doi: 10.1080/07853890.2023.2226907. PMID: 37337723; PMCID: PMC10283437. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10283437/ (Full text)