Clinical features of Japanese patients with gastrointestinal long-COVID symptoms

Introduction:

Although the development of new therapeutic approaches and vaccines has decreased coronavirus disease 2019 (COVID-19)-associated mortality, prolonged systemic symptoms after COVID-19, termed long-COVID, have been a major concern, considering their potential impact on health-related quality of life (QOL). Gastrointestinal (GI) symptoms, including diarrhea and abdominal pain, have been reported in patients with long-COVID even months after the initial COVID-19 symptoms have resolved.

Although emerging evidence suggests that GI symptoms in long-COVID are affected by the dysregulation of the immune system or ongoing inflammation and damage to the GI tract caused by the initial COVID-19 infection, the clinical features of patients with GI long-COVID symptoms remain elusive. Our study aimed to clarify these features.

Source: Kazuma Yagi, Takanori Asakura, Hideki Terai, Keiko Ohgino, Katsunori Masaki, Ho Namkoong, Shotaro Chubachi, Jun Miyata, Ichiro Kawada, Nobuhiro Kodama, Satoshi Sakamoto, Akira Umeda, Takashi Ishiguro, Makoto Ishii, Koichi Fukunaga. JGH Open. First published: 06 December 2023 https://doi.org/10.1002/jgh3.13006 https://onlinelibrary.wiley.com/doi/full/10.1002/jgh3.13006 (Full text)

Immunosuppression in ME may underlie energy deficits that drive ME symptomology

Interview of Dr. Armin Alaedini by Bronc

In October of 2023 the UK the Department of Health and Social Care held a public consultation to improve the care/life outcomes for people with ME. It included an acknowledgement that there has been a lack of biomedical research into ME but failed to accept the very negative impact this has had on the lives of people living with the illness. It also failed to point the finger at those responsible for this which includes the National Institute of Clinical Excellence and the Medical Research Council amongst others.

Despite calling for more research into ME there is acknowledgement that this will need substantial sums of money for this to happen. The DHSC consultation also asked for views about its plans which included a section about disability benefits and how the Department of Work and Pensions wants to improve the service it provides to those people who claim disability benefits. This laughable comment ignores the war on people claiming disability benefits which has been waged by the DWP since 2010. To compound matters the British government recently announced that it wants to make it harder for people to claim disability benefits and snoop on their bank accounts.

The DWP has consistently failed to acknowledge the debilitating nature of ME and instead focuses on the fluctuating nature of the illness to deny many people with ME disability benefits such as ESA and PIP.

Thankfully, there is plenty of evidence revealing how people with ME suffer from a suppressed immune response which accounts for many of the debilitating symptoms of the illness.

I recently talked with Dr. Armin Alaedini about his recent research into this issue. Dr Alaedini is an assistant professor at Columbia University and principal investigator at the Alaedini Lab. Its research is aimed at identifying ‘novel biomarkers, understanding disease mechanism, and finding therapeutic targets in gastrointestinal and neuropsychiatric disease.’ He is chair of ME/CFS Biospecimen Resource Access Committee at the National Institute of Neurological Disorders and Stroke and a member of the Neurobiology of Pain Study Section at NIH.

Dr Alaedini took time out of his busy schedule to talk to me about his research into ME.

How did you get involved in the field of ME research?

I have always been interested in the study of complex medical conditions, especially those that are poorly understood and understudied. I became specifically involved in ME research because of my acquaintance with Dr. Suzanne Vernon, who at that time was the chief scientific officer at The Solve ME/CFS Initiative. I was fortunate to have her support for a NIH-funded project, which resulted in our recent publication that demonstrates how microbial translocation links gastrointestinal, immunologic, and metabolic defects in ME/CFS.

In the paper you co-authored, Suppressed immune and metabolic responses to intestinal damage-associated microbial translocation in myalgic encephalomyelitis/chronic fatigue syndrome, it notes that the relationship between immunologic, metabolic and gastrointestinal abnormalities remains unclear. In your study you examined two groups of people with ME: one at rest and one undergoing an exercise challenge. They were compared to a group of healthy people. Can you explain what differences you noted between the healthy control group and the people with ME and between the two groups of people with ME? What may have caused this elevated antibody response to microbial agents in people with ME?

I had been particularly intrigued by the fact that gastrointestinal complaints are common in ME/CFS. Data from the patients in our study clearly confirmed this, showing that gastrointestinal symptoms were indeed much more common and more severe in ME/CFS study participants than in the non-ME/CFS controls. Along with this, we found a specific marker of injury or damage to the intestinal lining, called FABP2, to be higher in the blood of ME/CFS participants than in controls, providing a potential biological link to least some of the associated gastrointestinal symptoms. Increased intestinal permeability due to damage can lead to greater translocation of dietary and microbial antigens, which are typically constrained within the gut lumen, across the intestinal barrier. This, in turn, may result in an immune response to those translocated dietary and microbial products to counter and remove the potentially inflammatory antigens from systemic circulation.

Indeed, our data pointed to a significant increase in antibody responses to microbial and dietary antigens in ME/CFS patients in comparison to controls. What especially surprised us, however, was the fact that we did not observe an expected rise in the more immediate, or what we call “acute-phase”, innate immune responses. Specifically, we found that despite the increased markers of intestinal damage and higher antibody responses, ME/CFS patients did not exhibit a significant acute-phase immune response to counter circulating microbial products. This was suggestive of a suppressed systemic immune response that could possibly explain some of the ME/CFS symptoms.

Your study also noted ‘Enhanced antibody response to dietary antigens in ME/CFS’. What might be causing this?

The antibody response to dietary antigens is likely part of the same process resulting from a dysfunctional intestinal barrier that results in an enhanced immune response to the contents of the gut lumen. These would include both microbial and dietary antigens that the immune system is generally tolerant to and does not mount a significant antibody response against under normal conditions.

People with ME suffer from post exertion malaise which means that exercise will exacerbate their symptoms. What differences did you note between the healthy participants and people with ME who took the exercise challenge? What might be causing the differences in their response to exercise?

Intense exercise is known to cause increased intestinal permeability. Therefore, a maximal exercise challenge can be a particularly useful tool to better understand the effect of gut barrier function on the dysfunctional immune responses we were seeing in the ME/CFS cohort. The data from the exercise challenge confirmed our earlier data, suggesting that ME/CFS patients have a dysfunctional immune response, characterized by a suppressed innate/acute-phase response that is ineffective at countering microbial translocation from the intestinal tract into systemic circulation.

At the same time, another part of the immune response, the adaptive immune system, tries to compensate for this dysfunction by producing antibodies against those microbial antigens. However, the antibody response appears to be inadequate, as the ME/CFS patients continued to have increased circulating microbial antigens. We hypothesize that these microbial antigens can trigger downstream inflammatory responses that impact the central nervous system and may contribute to some of the hallmark symptoms of ME/CFS, such as fatigue.

We also compared metabolic responses in response to exercise between ME/CFS and control study participants. Of particular significance, we found a suppression of glucose and citrate metabolic responses in ME/CFS that to some extent correlated with the suppressed innate immune responses in these patients. This dysfunctional metabolic response is not only conceivably capable of contributing to the observed immunosuppression in ME/CFS, but it may also further underlie energy deficits that drive ME/CFS symptomology.

In your study you observed an increase in antibody responses to both microbial and dietary antigens, reflecting greater epithelial cell damage, which point to enhanced translocation of gut luminal antigens across a compromised intestinal barrier in ME/CFS. Did your findings point to a possible treatment for this damage to the intestinal barrier?

Indeed, the data point to a number of potential targets to consider for therapy in the context of ME/CFS. These include reducing or repairing the intestinal damage in order to decrease the microbial translocation; blocking or sequestering the already translocated microbial antigens; reversing the identified defects in the acute-phase immune responses towards the microbial antigens, and targeting the suppressed metabolic pathways.

What further research is needed to address the issues highlighted in your study?

More research is needed to better understand the relevance and level of contribution of the identified defects in the intestinal barrier, immune response, and metabolic pathways to ME/CFS symptomology, as well as to further characterize the molecular pathways involved, in order to move this research closer to development of effective treatments for ME/CFS.

Gastrointestinal symptoms of long COVID-19 related to the ectopic colonization of specific bacteria that move between the upper and lower alimentary tract and alterations in serum metabolites

Abstract:

Background: Since the coronavirus disease 2019 (COVID-19) outbreak, many COVID-19 variants have emerged, causing several waves of pandemics and many infections. Long COVID-19, or long-term sequelae after recovery from COVID-19, has aroused worldwide concern because it reduces patient quality of life after rehabilitation. We aimed to characterize the functional differential profile of the oral and gut microbiomes and serum metabolites in patients with gastrointestinal symptoms associated with long COVID-19.

Methods: We prospectively collected oral, fecal, and serum samples from 983 antibiotic-naïve patients with mild COVID-19 and performed a 3-month follow-up postdischarge. Forty-five fecal and saliva samples, and 25 paired serum samples were collected from patients with gastrointestinal symptoms of long COVID-19 at follow-up and from healthy controls, respectively. Eight fecal and saliva samples were collected without gastrointestinal symptoms of long COVID-19 at follow-up. Shotgun metagenomic sequencing of fecal samples and 2bRAD-M sequencing of saliva samples were performed on these paired samples. Two published COVID-19 gut microbiota cohorts were analyzed for comparison. Paired serum samples were analyzed using widely targeted metabolomics.

Results: Mild COVID-19 patients without gastrointestinal symptoms of long COVID-19 showed little difference in the gut and oral microbiota during hospitalization and at follow-up from healthy controls. The baseline and 3-month samples collected from patients with gastrointestinal symptoms associated with long COVID-19 showed significant differences, and ectopic colonization of the oral cavity by gut microbes including 27 common differentially abundant genera in the Proteobacteria phylum, was observed at the 3-month timepoint. Some of these bacteria, including Neisseria, Lautropia, and Agrobacterium, were highly related to differentially expressed serum metabolites with potential toxicity, such as 4-chlorophenylacetic acid, 5-sulfoxymethylfurfural, and estradiol valerate.

Conclusions: Our study characterized the changes in and correlations between the oral and gut microbiomes and serum metabolites in patients with gastrointestinal symptoms associated with long COVID-19. Additionally, our findings reveal that ectopically colonized bacteria from the gut to the oral cavity could exist in long COVID-19 patients with gastrointestinal symptoms, with a strong correlation to some potential harmful metabolites in serum.

Source: Zhang D, Weng S, Xia C, Ren Y, Liu Z, Xu Y, Yang X, Wu R, Peng L, Sun L, Zhu J, Liang X, Jia Y, Wang H, Chen Q, Liu D, Chen Y, Guo H, Han X, Jin Z, Chen C, Yang X, Li Z, Huang H. Gastrointestinal symptoms of long COVID-19 related to the ectopic colonization of specific bacteria that move between the upper and lower alimentary tract and alterations in serum metabolites. BMC Med. 2023 Jul 19;21(1):264. doi: 10.1186/s12916-023-02972-x. PMID: 37468867; PMCID: PMC10355065. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10355065/ (Full text)

Suppressed immune and metabolic responses to intestinal damage-associated microbial translocation in myalgic encephalomyelitis/chronic fatigue syndrome

Highlights:

  • Elevation of FABP2, a marker of intestinal cell damage in ME/CFS.
  • Absence of optimal acute-phase LBP and sCD14 anti-microbial responses in ME/CFS.
  • Compensatory but inadequate B cell response to microbial translocation in ME/CFS.
  • Enhanced IL-10 regulatory response may drive the observed immunosuppression.
  • Glucose and citrate metabolic dysfunction in ME/CFS may link the IL-10 activation and suppressed anti-microbial responses.

Abstract:

The etiology and mechanism of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are poorly understood and no biomarkers have been established. Specifically, the relationship between the immunologic, metabolic, and gastrointestinal abnormalities associated with ME/CFS and their relevance to established symptoms of the condition remain unclear.

Relying on data from two independent cohorts of ME/CFS and control study participants, one at rest and one undergoing an exercise challenge, we identify a state of suppressed acute-phase innate immune response to microbial translocation in conjunction with a compromised gut epithelium. This immunosuppression, along with observed enhancement of compensatory antibody responses to counter the microbial translocation, was associated with and may be mediated by alterations in glucose and citrate metabolism and an IL-10 immunoregulatory response. Our findings provide novel insights into mechanistic pathways, biomarkers, and potential therapeutic targets in ME/CFS, including in the context of exertion, with relevance to both intestinal and extra-intestinal symptoms.

Source: Melanie Uhde, Alyssa C. Indart, Peter H.R. Green, Robert H. Yolken, Dane B. Cook, Sanjay K. Shukla, Suzanne D. Vernon, Armin Alaedini.
Suppressed immune and metabolic responses to intestinal damage-associated microbial translocation in myalgic encephalomyelitis/chronic fatigue syndrome. Brain, Behavior, & Immunity – Health, 2023, 100627. ISSN 2666-3546, https://doi.org/10.1016/j.bbih.2023.100627.
https://www.sciencedirect.com/science/article/pii/S2666354623000418 (Full text)

Disorders of gut-brain interaction in post-acute COVID-19 syndrome

Abstract:

The novel coronavirus SARS-CoV-2 is responsible for the devastating pandemic which has caused more than 5 million deaths across the world until today. Apart from causing acute respiratory illness and multiorgan dysfunction, there can be long-term multiorgan sequalae after recovery, which is termed ‘long COVID-19’ or ‘post-acute COVID-19 syndrome’. Little is known about long-term gastrointestinal (GI) consequences, occurrence of post-infection functional gastrointestinal disorders and impact the virus may have on overall intestinal health.

In this review, we put forth the various mechanisms which may lead to this entity and possible ways to diagnose and manage this disorder. Hence, making physicians aware of this spectrum of disease is of utmost importance in the present pandemic and this review will help clinicians understand and suspect the occurrence of functional GI disease post recovery from COVID-19 and manage it accordingly, avoiding unnecessary misconceptions and delay in treatment.

Source: Golla R, Vuyyuru SK, Kante B, Kedia S, Ahuja V. Disorders of gut-brain interaction in post-acute COVID-19 syndrome. Postgrad Med J. 2022 Jul 1:postgradmedj-2022-141749. doi: 10.1136/pmj-2022-141749. Epub ahead of print. PMID: 35777934. https://pmj.bmj.com/content/early/2022/07/01/pmj-2022-141749 (Full text)

Gastric herpes simplex virus type 1 infection is associated with functional gastrointestinal disorders in the presence and absence of comorbid fibromyalgia: a pilot case-control study

Abstract:

Purpose: Animal studies have linked gastric herpesvirus infections to symptoms associated with functional gastrointestinal disorders (FGIDs). Herpesviruses have also been hypothesized to contribute to fibromyalgia (FM), a chronic pain syndrome frequently comorbid with FGIDs. The purpose of this study was to compare the prevalence of gastric herpesvirus infection in patients with FGIDs, with and without comorbid FM, to that of controls.

Methods: For this pilot case-control study, we enrolled 30 patients who met both the Rome IV diagnostic criteria for one or more FGIDs and the American College of Rheumatology 2010 criteria for FM, 15 patients with one or more FGIDs without comorbid FM, and 15 control patients. Following endoscopic examination, gastric biopsies were analyzed for herpesvirus DNA and protein, Helicobacter pylori infection, and histological evidence of gastritis. Importantly, the viral nonstructural protein ICP8 was used as a marker to differentiate cell-associated actively replicating virus from latent infection and/or free virus passing through the GI tract.

Results: Gastric herpes simplex virus type 1 (HSV-1) infection, as indicated by ICP8 presence, was significantly associated with FGIDs in the presence (OR 70.00, 95% CI 7.42-660.50; P < .001) and absence (OR 38.50, 95% CI 3.75-395.40; P < .001) of comorbid FM. Neither histological gastritis nor H. pylori infection were found to be associated with FGIDs or FM.

Conclusions: HSV-1 infection was identified in gastric mucosal biopsies from patients with diverse FGIDs, with and without comorbid FM. Larger, multi-center studies investigating the prevalence of this association are warranted.

Source: Duffy C, Pridgen WL, Whitley RJ. Gastric herpes simplex virus type 1 infection is associated with functional gastrointestinal disorders in the presence and absence of comorbid fibromyalgia: a pilot case-control study. Infection. 2022 Apr 21. doi: 10.1007/s15010-022-01823-w. Epub ahead of print. PMID: 35445970.  https://link.springer.com/article/10.1007/s15010-022-01823-w (Full text)

Detection of herpesviruses and parvovirus B19 in gastric and intestinal mucosa of chronic fatigue syndrome patients

Abstract:

BACKGROUND: Human herpesvirus-6 (HHV-6), Epstein-Barr virus and parvovirus B19 have been suggested as etiological agents of chronic fatigue syndrome but none of these viruses is consistently detected in all patients. However, active viral infections may be localized in specific tissues, and, therefore, are not easily detectable. The aim of this study was to investigate the presence of HHV-6, HHV-7, EBV and parvovirus B19 in the gastro-intestinal tract of CFS patients.

PATIENTS AND METHODS: Using real-time PCR, viral DNA loads were quantified in gastro-intestinal biopsies of 48 CFS patients and 35 controls.

RESULTS: High loads of HHV-7 DNA were detected in most CFS and control biopsies. EBV and HHV-6 were detected in 15-30% of all biopsies. Parvovirus B19 DNA was detected in 40% of the patients versus less than 15% of the controls.

CONCLUSION: Parvovirus B19 may be involved in the pathogenesis of CFS, at least for a subset of patients. The gastro-intestinal tract appears as an important reservoir of infection for several potentially pathogenic viruses.

 

Source: Frémont M, Metzger K, Rady H, Hulstaert J, De Meirleir K. Detection of herpesviruses and parvovirus B19 in gastric and intestinal mucosa of chronic fatigue syndrome patients. In Vivo. 2009 Mar-Apr;23(2):209-13. http://iv.iiarjournals.org/content/23/2/209.long (Full article)