It Ain't Over 'Til It's Over: SARS CoV-2 and Post-infectious Gastrointestinal Dysmotility

Clinical Practice Updates: AGA Clinical Practice Update on GI Manifestations and Autonomic or Immune Dysfunction in Hypermobile Ehlers-Danlos Syndrome: Expert Review

DESCRIPTION

The purpose of this Clinical Practice Update Expert Review is to describe key principles in the evaluation and management of patients with disorders of gut-brain interaction (DGBI) and hypermobile Ehlers-Danlos syndrome (hEDS) or hypermobility spectrum disorders (HSDs) with coexisting postural orthostatic tachycardia syndrome (POTS) and/or mast cell activation syndrome (MCAS).

METHODS

This expert review/commentary was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the Clinical Practice Updates Committee and external peer review through standard procedures of Clinical Gastroenterology and Hepatology. These Best Practice Advice statements were drawn from a review of the published literature and from expert opinion. Because systematic reviews were not performed, these Best Practice Advice statements do not carry formal ratings regarding the quality of evidence or strength of the presented considerations. BEST PRACTICE ADVICE 1: Clinicians should be aware of the observed associations between hEDS or HSDs and POTS and/or MCAS and their overlapping gastrointestinal (GI) manifestations; while theoretical explanations exist, experimental evidence of the biological mechanisms that explain relationships is limited and evolving. BEST PRACTICE ADVICE 2: Testing for POTS/MCAS should be targeted to patients presenting with clinical manifestations of POTS/MCAS, but universal testing for POTS/MCAS in all patients with hEDS/HSDs is not supported by the current evidence. BEST PRACTICE ADVICE 3: Gastroenterologists seeing patients with DGBI should inquire about joint hypermobility and strongly consider incorporating the Beighton score for assessing joint hypermobility into their practice as a screening tool; if the screen is positive, gastroenterologists may consider applying 2017 diagnostic criteria to diagnose hEDS (https://www.ehlers-danlos.com/wp-content/uploads/2017/05/hEDS-Dx-Criteria-checklist-1.pdf) or offer appropriate referral to a specialist where resources are available. BEST PRACTICE ADVICE 4: Testing for POTS through postural vital signs (eg, symptomatic increase in heart rate of 30 beats/min or more with 10 minutes of standing during an active stand or head-up tilt table test in the absence of orthostasis) and referral to specialty practices (eg, cardiology or neurology) for autonomic testing should be considered in patients with hEDS/HSDs and refractory GI symptoms who also report orthostatic intolerance after exclusion of medication side effects and appropriate lifestyle or behavioral modifications (eg, adequate hydration and physical exercise) have been attempted but is not required for all patients with hEDS/HSDs who report GI symptoms alone. BEST PRACTICE ADVICE 5: In patients presenting to gastroenterology providers, testing for mast cell disorders including MCAS should be considered in patients with hEDS/HSDs and DGBI who also present with episodic symptoms that suggest a more generalized mast cell disorder (eg, visceral and somatic pain, pruritus, flushing, sweating, urticaria, angioedema, wheezing, tachycardia, abdominal cramping, vomiting, nausea, diarrhea, urogynecological and neurological complaints) involving 2 or more physiological systems (eg, cutaneous, GI, cardiac, respiratory, and neuropsychiatric), but current data do not support the use of these tests for routine evaluation of GI symptoms in all patients with hEDS/HSDs without clinical or laboratory evidence of a primary or secondary mast cell disorder. BEST PRACTICE ADVICE 6: If MCAS is suspected, diagnostic testing with serum tryptase levels collected at baseline and 1-4 hours following symptom flares may be considered by the gastroenterologist; increases of 20% above baseline plus 2 ng/mL are necessary to demonstrate evidence of mast cell activation. BEST PRACTICE ADVICE 7: If a diagnosis of MCAS is supported through clinical and/or laboratory features, patients should be referred to an allergy specialist or mast cell disease research center where additional testing (eg, urinary N-methylhistamine, leukotriene E4, 11β-prostaglandin F2) may be performed. BEST PRACTICE ADVICE 8: Diagnostic evaluation of GI symptoms consistent with DGBI in patients with hEDS/HSDs and comorbid POTS and/or MCAS should follow a similar approach to the evaluation of DGBI as in the general population including the use of a positive symptom-based diagnostic strategy and limited noninvasive testing. BEST PRACTICE ADVICE 9: Testing for celiac disease may be considered earlier in the diagnostic evaluation of patients with hEDS/HSDs who report a variety of GI symptoms and not only limited to those with diarrhea. There is insufficient research to support routine testing for disaccharidase deficiencies or other diet-mediated mechanisms as causes of GI symptoms in hEDS/HSDs. BEST PRACTICE ADVICE 10: Diagnostic testing for functional defecation disorders with anorectal manometry, balloon expulsion test, or defecography should be considered in patients with hEDS/HSDs and lower GI symptoms such as incomplete evacuation given the high prevalence of pelvic floor dysfunction, especially rectal hyposensitivity, in this population. BEST PRACTICE ADVICE 11: In patients with hEDS/HSDs and comorbid POTS who report chronic upper GI symptoms, timely diagnostic testing of gastric motor functions (eg, measurement of gastric emptying and/or accommodation) should be considered after appropriate exclusion of anatomical and structural diseases, as abnormal gastric emptying may be more common than in the general population. BEST PRACTICE ADVICE 12: Medical management of GI symptoms in hEDS/HSDs and POTS/MCAS should focus on treating the most prominent GI symptoms and abnormal GI function test results. In addition to general DGBIs and GI motility disorder treatment, management should also include treating any symptoms attributable to POTS and/or MCAS. BEST PRACTICE ADVICE 13: Treatment of POTS may include increasing fluid and salt intake, exercise training, and use of compression garments. Special pharmacological treatments for volume expansion, heart rate control, and vasoconstriction with integrated care from multiple specialties (eg, cardiology, neurology) should be considered in patients who do not respond to conservative lifestyle measures. BEST PRACTICE ADVICE 14: When MCAS is suspected, patients can benefit from treatment with histamine receptor antagonists and/or mast cell stabilizers, in addition to avoiding triggers such as certain foods, alcohol, strong smells, temperature changes, mechanical stimuli (eg, friction), emotional distress (eg, pollen, mold), or specific medications (eg, opioids, nonsteroidal anti-inflammatory agents, iodinated contrast). BEST PRACTICE ADVICE 15: Besides general nutritional support, special diets including a gastroparesis diet (ie, small particle diet) and various elimination diets (eg, low fermentable carbohydrates, gluten- or dairy-free, low-histamine diets) can be considered for improving GI symptoms. Dietary interventions should be delivered with appropriate nutritional counseling or guidance to avoid the pitfalls of restrictive eating. BEST PRACTICE ADVICE 16: Management of chronic GI symptoms in patients with hEDS/HSDs who do not exhibit symptoms consistent with POTS or MCAS should align with existing approaches to management of DGBI and GI motility disorders in the general population, including integrated multidisciplinary care involving multiple specialties, where appropriate (eg, cardiology, rheumatology, dietician, psychology).

Chronic inflammation in post-acute sequelae of COVID-19 modulates gut microbiome: a review of literature on COVID-19 sequelae and gut dysbiosis

BACKGROUND

Long COVID or Post-acute sequelae of COVID-19 is an emerging syndrome, recognized in COVID-19 patients who suffer from mild to severe illness and do not recover completely. Most studies define Long COVID, through symptoms like fatigue, brain fog, joint pain, and headache prevailing four or more weeks post-initial infection. Global variations in Long COVID presentation and symptoms make it challenging to standardize features of Long COVID. Long COVID appears to be accompanied by an auto-immune multi-faceted syndrome where the virus or viral antigen persistence causes continuous stimulation of the immune response, resulting in multi-organ immune dysregulation.

MAIN TEXT

This review is focused on understanding the risk factors of Long COVID with a special emphasis on the dysregulation of the gut-brain axis. Two proposed mechanisms are discussed here. The first mechanism is related to the dysfunction of angiotensin-converting enzyme 2 receptor due to Severe Acute Respiratory Syndrome Corona Virus 2 infection, leading to impaired mTOR pathway activation, reduced AMP secretion, and causing dysbiotic changes in the gut. Secondly, gut-brain axis dysregulation accompanied by decreased production of short-chain fatty acids, impaired enteroendocrine cell function, and increased leakiness of the gut, which favors translocation of pathogens or lipopolysaccharide in circulation causing the release of pro-inflammatory cytokines. The altered Hypothalamic-Pituitary-Adrenal axis is accompanied by the reduced level of neurotransmitter, and decreased stimulation of the vagus nerve, which may cause neuroinflammation and dysregulation of serum cortisol levels. The dysbiotic microbiome in Long COVID patients is characterized by a decrease in beneficial short chain fatty acid-producing bacteria (Faecalibacterium, Ruminococcus, Dorea, and Bifidobacterium) and an increase in opportunistic bacteria (Corynebacterium, Streptococcus, Enterococcus). This dysbiosis is transient and may be impacted by interventions including probiotics, and dietary supplements.

CONCLUSIONS

Further studies are required to understand the geographic variation, racial and ethnic differences in phenotypes of Long COVID, the influence of viral strains on existing and emerging phenotypes, to explore long-term effects of gut dysbiosis, and gut-brain axis dysregulation, as well as the potential role of diet and probiotics in alleviating those symptoms.

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

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.

Gastrointestinal disorders in post-COVID syndrome. Clinical guidelines

Summary Post- COVID syndrome refers to the long-term consequences of a new coronavirus infection COVID-19, which includes a set of symptoms that develop or persist after COVID-19. Symptoms of gastrointestinal disorders in post- COVID syndrome, due to chronic infl ammation, the consequences of organ damage, prolonged hospitalization, social isolation, and other causes, can be persistent and require a multidisciplinary approach. The presented clinical practice guidelines consider the main preventive and therapeutic and diagnostic approaches to the management of patients with gastroenterological manifestations of postCOVID syndrome. The Guidelines were approved by the 17th National Congress of Internal Medicine and the 25th Congress of Gastroenterological Scientifi c Society of Russia.

The Potential Role of Microorganisms on Enteric Nervous System Development and Disease

The enteric nervous system (ENS), the inherent nervous system of the gastrointestinal (GI) tract is a vast nervous system that controls key GI functions, including motility. It functions at a critical interface between the gut luminal contents, including the diverse population of microorganisms deemed the microbiota, as well as the autonomic and central nervous systems. Critical development of this axis of interaction, a key determinant of human health and disease, appears to occur most significantly during early life and childhood, from the pre-natal through to the post-natal period. These factors that enable the ENS to function as a master regulator also make it vulnerable to damage and, in turn, a number of GI motility disorders. Increasing attention is now being paid to the potential of disruption of the microbiota and pathogenic microorganisms in the potential aetiopathogeneis of GI motility disorders in children. This article explores the evidence regarding the relationship between the development and integrity of the ENS and the potential for such factors, notably dysbiosis and pathogenic bacteria, viruses and parasites, to impact upon them in early life.

Spike S1 domain interactome in non-pulmonary systems: A role beyond the receptor recognition

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes Coronavirus Disease 2019 (COVID-19), which, since 2019 in China, has rapidly become a worldwide pandemic. The aggressiveness and global spread were enhanced by the many SARS-CoV-2 variants that have been isolated up to now. These mutations affect mostly the viral glycoprotein Spike (S), the capsid protein mainly involved in the early stages of viral entry processes, through the recognition of specific receptors on the host cell surface. In particular, the subunit S1 of the Spike glycoprotein contains the Receptor Binding Domain (RBD) and it is responsible for the interaction with the angiotensin-converting enzyme 2 (ACE2). Although ACE2 is the primary Spike host receptor currently studied, it has been demonstrated that SARS-CoV-2 is also able to infect cells expressing low levels of ACE2, indicating that the virus may have alternative receptors on the host cells. The identification of the alternative receptors can better elucidate the pathogenicity and the tropism of SARS-CoV-2. Therefore, we investigated the Spike S1 interactomes, starting from host membrane proteins of non-pulmonary cell lines, such as human kidney (HK-2), normal colon (NCM460D), and colorectal adenocarcinoma (Caco-2). We employed an affinity purification-mass spectrometry (AP-MS) to pull down, from the membrane protein extracts of all cell lines, the protein partners of the recombinant form of the Spike S1 domain. The purified interactors were identified by a shotgun proteomics approach. The lists of S1 potential interacting proteins were then clusterized according to cellular localization, biological processes, and pathways, highlighting new possible S1 intracellular functions, crucial not only for the entrance mechanisms but also for viral replication and propagation processes.