Age, Inflammation, and Disease Location Are Critical Determinants of Intestinal Expression of SARS-CoV-2 Receptor ACE2 and TMPRSS2 in Inflammatory Bowel Disease

Increased ACE2 and TMPRSS2 expression in ulcerative colitis

Ulcerative colitis (UC) is a cryptogenic inflammatory bowel disease, and there is an urgent need to elucidate its pathogenesis. ACE2 and TMPRSS2, the entry molecules of SARS-CoV-2, are reportedly associated with the disease; however, no consensus has been reached yet. In this study, we examined the expression of ACE2 and TMPRSS2 in colon and rectal specimens of UC. We collected colorectal specimens from 60 patients (30 patients with UC and 30 controls from 2018 to 2021) and analyzed the proportion and intensity of ACE2 and TMPRSS2 using immunohistochemistry. The results revealed a significant increase in the proportion of ACE2 expression and the intensity of TMPRSS2 expression in patients with UC. ACE2 and TMPRSS2 expression in UC remained unaffected by the COVID-19 pandemic. We demonstrated that ACE2 and TMPRSS2 are likely involved in the pathogenesis of UC.

The association between ulcerative colitis and COVID-19 severity: a systematic review and meta-analysis systematic review

PURPOSE

After the COVID-19 pandemic, many challenges arose regarding the impact of this disease on people with ulcerative colitis. The aims of this study were to estimate the prevalence, severity, and death consequences of COVID-19 in patients with ulcerative colitis using a systematic review and meta-analysis.

METHODS

This study was conducted using a systematic review and meta-analysis method in the field of prevalence, severity, and clinical consequences of COVID-19 in people with ulcerative colitis worldwide. The search was conducted in international scientific databases, such as Web of Science, PubMed, Scopus, Cochrane Library, and Google Scholar, from the beginning of 2020 to October 2023. The quality of the eligible studies was assessed using the Strobe and Newcastle Ottawa checklists. The data were analyzed using a fixed-effects model in the meta-analysis. Subgroup analysis and meta-regression were performed using STATA version 17.

RESULTS

Nineteen studies with a sample size of 224,520 patients were included in this meta-analysis. The results showed that, in COVID-19 patients with ulcerative colitis, the prevalence of hospitalization, death, COVID-19 severity, and mortality rate in severe patients was 54% (95% CI, 27-80%), 10% (95% CI, 4-16%), 20% (95% CI, 8-34%), 63% (95% CI, 46-80%), respectively. In comparison with the general population, the odds ratio (OR) of hospitalization in patients due to COVID-19 was OR = 1.28 (95% CI, 1.19-1.38, P < 0.001), and the chance of severe COVID-19 was OR = 1.30 (95% CI, 1.22-1.53, P < 0.001).

CONCLUSION

The probability of contracting the severe type of COVID-19 and hospitalization in patients with ulcerative colitis was higher than in the general population.

COVID-19 and Gastrointestinal Tract: From Pathophysiology to Clinical Manifestations

Background: Since its first report in Wuhan, China, in December 2019, COVID-19 has become a pandemic, affecting millions of people worldwide. Although the virus primarily affects the respiratory tract, gastrointestinal symptoms are also common. The aim of this narrative review is to provide an overview of the pathophysiology and clinical manifestations of gastrointestinal COVID-19. Methods: We conducted a systematic electronic search of English literature up to January 2023 using Medline, Scopus, and the Cochrane Library, focusing on papers that analyzed the role of SARS-CoV-2 in the gastrointestinal tract. Results: Our review highlights that SARS-CoV-2 directly infects the gastrointestinal tract and can cause symptoms such as diarrhea, nausea/vomiting, abdominal pain, anorexia, loss of taste, and increased liver enzymes. These symptoms result from mucosal barrier damage, inflammation, and changes in the microbiota composition. The exact mechanism of how the virus overcomes the acid gastric environment and leads to the intestinal damage is still being studied. Conclusions: Although vaccination has increased the prevalence of less severe symptoms, the long-term interaction with SARS-CoV-2 remains a concern. Understanding the interplay between SARS-CoV-2 and the gastrointestinal tract is essential for future management of the virus.

Severe acute respiratory syndrome coronavirus 2 infection does not worsen the course of inflammatory bowel disease in the long term

BACKGROUND

The long-term outcome of inflammatory bowel disease (IBD) patients after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is under investigation.

AIM

To assess, in a prospective study, whether a recent SARS-CoV-2 infection increases the risk of IBD relapse within 12 months.

METHODS

From March to April 2021, all IBD patients with recent (<2 months) SARS-CoV-2 infection (Cases) were enrolled. For each enrolled Case, four IBD Controls with no history of infection were considered. Clinical course of IBD was recorded for 12 months. Inclusion criteria: well defined diagnosis of IBD; age ≥18 and ≤85 years; 12-month follow-up; consent. Exclusion criteria: incomplete data; SARS-CoV-2 infection after enrollment. Additional inclusion criteria: recent SARS-CoV-2 infection for Cases; no history of SARS-CoV-2 infection for Controls. Data expressed as median [range]. Statistical analysis: Student-t-Test, Mann-Whitney U-test, χ2 test, multivariate logistic regression model [odds ratio (95% confidence interval)], Kaplan-Meier curves.

RESULTS

One hundred forty-three IBD patients were enrolled. The analysis included 118 patients (22 met the exclusion criteria, three lost at follow-up): 29 (24.6%) Cases and 89 (75.4%) Controls. Demographic and clinical characteristics were comparable between groups. During the 12-month study, the frequency of IBD relapse was comparable between Cases and Controls [8 (27%) vs 19 (21%); P = 0.65]. At univariate analysis, SARS-CoV-2 infection was not a risk factor for IBD relapse within 12 months [1.5 (0.6-3.9); P = 0.34]. At multivariate analysis, IBD activity at baseline was the only risk factor for relapse [3.2 (1.1-9.1); P = 0.03]. Kaplan-Meier curves showed that survival from IBD relapse was comparable between Cases and Controls (P = 0.33).

CONCLUSION

In a prospective 12-month study, a recent SARS-CoV-2 infection did not increase the risk of clinical relapse of IBD in the long term.

Gut vascular barrier in the pathogenesis and resolution of Crohn's disease: A novel link from origination to therapy

The gut vascular barrier (GVB) is the deepest layer of the gut barrier. It mainly comprised gut vascular endothelial cells, enteric glial cells, and pericytes. The GVB facilitates nutrient absorption and blocks bacterial translocation through its size-restricted permeability. Accumulating evidence suggests that dysfunction of this barrier correlates with several clinical pathologies including Crohn's disease (CD). Significant progress has been made to elucidate the mechanism of GVB dysfunction and to confirm the participation of disrupted GVB in the course of CD. However, further analyses are required to pinpoint the specific roles of GVB in CD pathogenesis. Many preclinical models and clinical trials have demonstrated that various agents are effective in protecting the GVB integrity and thus providing a potential CD treatment strategy. Through this review, we established a systemic understanding of the role of GVB in CD pathogenesis and provided novel insights for GVB-targeting strategies in CD treatment.

Comorbidities of COVID-19 Patients

The novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) responsible for the coronavirus disease outbreak initiated in 2019 (COVID-19) has been shown to affect the health of infected patients in a manner at times dependent on pre-existing comorbidities. Reported here is an overview of the correlation between comorbidities and the exacerbation of the disease in patients with COVID-19, which may lead to poor clinical outcomes or mortality. General medical issues are also reviewed, such as the types of symptoms present in people infected with SARS-CoV-2, the long-term effects of COVID-19 disease, and the types of treatment that are currently used.

The Outcome of COVID-19 Infection in Patients With Gastrointestinal Diseases: An Experience at a Tertiary Center

OBJECTIVE

Observing the impact of the coronavirus disease 2019 (COVID-19) pandemic on digestive diseases in hospitalized patients at the Department of Gastroenterology-Hepatology in "Mother Teresa" University Hospital Center (UHC),Tirana.

METHODS

This retrospective study was carried out from June 2020 to December 2021 involving 41 cases of patients >18 years who were positive for COVID-19 infection detected by RT-PCR (Reverse Transcription-Polymerase Chain Reaction) assays of nasopharyngeal swab specimens. The severity of COVID-19 infection was evaluated by hematological/biochemical parameters, blood oxygenation/need for oxygen, radiological data on pulmonary CT imaging.

RESULTS

Out of 2527 hospitalized cases, 1.6% (41) were positive for the infection. The average age was 60.05 +/- 15.008 years. The group of age with more patients (48.8%) was 41-60 years. Infected males were higher than females (p<0.001). Out of the total, 21% were vaccinated at the diagnosis. Most patients came from urban areas, more than a half from the capital. Frequency of the digestive diseases was: cirrhosis 31.7%, pancreatitis 21.9%, alcoholic liver disease 21.9%, gastrointestinal hemorrhage 19.5%, digestive cancer 14.6%, biliary diseases 7.3%, inflammatory bowel disease (IBD) 2.4%, other digestive diseases 4.8%. Fever (90%) and fatigue (78.04%) were the dominant clinical signs.  Biochemical and hematological parameters showed elevation of average value of aspartate amino transferase (AST), alanine transaminase (ALT) (AST>ALT, p<0.001), and bilirubin in all the patients. Higher levels of creatinine and significantly predictive value of systemic inflammation indices NLR (neutrophil to lymphocyte ratio ) and MLR (monocyte to lymphocyte ratio) were found in the fatality cases. Patients with cirrhosis had more severe form of COVID-19, lower blood oxygenation and needed treatment by O₂-therapy (p<0.046). Death rate was 12%. A strong correlation was found between the need for O₂-therapy and deaths (p<0.001) and between characteristic findings for COVID-19 in pulmonary CT imaging and low blood oxygenation (p<0.003).

CONCLUSION

Comorbidity with chronic diseases, such as liver cirrhosis, has an important impact on the severity and mortality of the patients with COVID-19 infection. Inflammatory indices, such as NLR (neutrophil to lymphocyte ratio) and MLR (monocyte to lymphocyte ratio), are useful tools in predicting the evolution toward severe forms of the disease.

COVID-19 susceptibility and clinical outcomes in inflammatory bowel disease: An updated systematic review and meta-analysis

The susceptibility, risk factors, and prognosis of COVID-19 in patients with inflammatory bowel disease (IBD) remain unknown. Thus, our study aims to assess the prevalence and clinical outcomes of COVID-19 in IBD. We searched PubMed, EMBASE, and medRxiv from 2019 to 1 June 2022 for cohort and case-control studies comparing the prevalence and clinical outcomes of COVID-19 in patients with IBD and in the general population. We also compared the outcomes of patients receiving and not receiving 5-aminosalicylates (ASA), tumour necrosis factor antagonists, biologics, systemic corticosteroids, or immunomodulators for IBD. Thirty five studies were eligible for our analysis. Pooled odds ratio of COVID-19-related hospitalisation, intensive care unit (ICU) admission, or death in IBD compared to in non-IBD were 0.58 (95% confidence interval (CI) = 0.28-1.18), 1.09 (95% CI = 0.27-4.47), and 0.67 (95% CI = 0.32-1.42), respectively. Inflammatory bowel disease was not associated with increased hospitalisation, ICU admission, or death. Susceptibility to COVID-19 did not increase with any drugs for IBD. Hospitalisation, ICU admission, and death were more likely with 5-ASA and corticosteroid use. COVID-19-related hospitalisation (Odds Ratio (OR): 0.53; 95% CI = 0.38-0.74) and death (OR: 0.13; 95% CI = 0.13-0.70) were less likely with Crohn's disease than ulcerative colitis (UC). In conclusion, IBD does not increase the mortality and morbidity of COVID-19. However, physicians should be aware that additional monitoring is needed in UC patients or in patients taking 5-ASA or systemic corticosteroids.

ACE2 in male genitourinary and endocrine systems: Does COVID-19 really affect these systems?

The virus that causes COVID-19 (Corona Virus Disease 2019), SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), is causing a worldwide pandemic, posing a substantial threat to human health. Patients show signs of pneumonia, ARDS, shock, acute cardiac injury, acute kidney injury and other complications. The SARS-CoV-2 receptor is angiotensin converting enzyme 2 (ACE2), which is an important component of the renin-angiotensin system (RAS). In addition, TMPRSS2 or other cofactors are needed to allow the virus to enter the host. Clinical patients have exhibited varying degrees of genitourinary and endocrine system damage, and some studies have also reported potential risks to the genitourinary and endocrine systems. This article reviews the mechanism underlying SARS-CoV-2 infection and the current studies on the male genitourinary and endocrine systems and proposes that more attention should be directed towards human reproductive and endocrine health during the SARS-CoV-2 epidemic.

What do we know about the renin angiotensin system and inflammatory bowel disease?

INTRODUCTION

The renin-angiotensin system (RAS) is an important homeostatic pathway, with emerging evidence for the impact of its components on inflammation and fibrosis in gastrointestinal tissues. This review aims to review current knowledge of the physiological mechanism of RAS in inflammatory bowel disease (IBD), and potential therapeutic implications.

AREAS COVERED

An extensive online literature review including Pubmed, Medline, and Google Scholar was undertaken. Discussion on the components of the RAS, localization, and physiological functions in the gastrointestinal tract, preclinical, and clinical data in IBD, and the relation with SARS-Cov-2 are covered in this review.

EXPERT OPINION

RAS inhibition may have a role as anti-fibrotic adjunct therapy. Targeting the local gastrointestinal RAS with novel modes of delivery may be a target for future therapeutics for IBD, given the widespread availability and safety of current options as utilized in other diseases. Further insight into the mechanism and downstream effects of gastrointestinal ACE2 may lead to a better understanding of the pathogenesis of IBD.

COVID-19 Pandemic: Insights into Interactions between SARS-CoV-2 Infection and MAFLD

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become an ongoing global health pandemic. Since 2019, the pandemic continues to cast a long shadow on all aspects of our lives, bringing huge health and economic burdens to all societies. With our in-depth understanding of COVID-19, from the initial respiratory tract to the later gastrointestinal tract and cardiovascular systems, the multiorgan involvement of this infectious disease has been discovered. Metabolic dysfunction-associated fatty liver disease (MAFLD), formerly named nonalcoholic fatty liver disease (NAFLD), is a major health issue closely related to metabolic dysfunctions, affecting a quarter of the world's adult population. The association of COVID-19 with MAFLD has received increasing attention, as MAFLD is a potential risk factor for SARS-CoV-2 infection and severe COVID-19 symptoms. In this review, we provide an update on the interactions between COVID-19 and MAFLD and its underlying mechanisms.

Inflammatory Bowel Disease Clinical Activity is Associated with COVID-19 Severity Especially in Younger Patients

BACKGROUND AND AIMS

Age is a major prognostic factor for COVID-19 outcomes. The effect of inflammatory bowel disease [IBD] activity on COVID-19 is unclear. We examined the relationship between IBD activity and COVID-19 severity according to age.

METHODS

We included IBD patients diagnosed with COVID-19, reported to SECURE-IBD between March 13, 2020 and August 3, 2021. Clinical IBD activity was measured by physician global assessment [PGA]. COVID-19-related outcomes were [1] intensive care unit [ICU] admission, ventilation or death, and [2] hospitalization. Using generalized estimating equations, we determined adjusted odds ratios [aOR, 95% confidence interval] for moderate and severe PGA vs clinical remission/mild PGA, controlling for demographics, medications and COVID-19 diagnosis period. We performed stratified analyses by age [≤50 vs >50 years].

RESULTS

Among 6078 patients, adverse COVID-19 outcomes were more common with active IBD: ICU/ventilation/death in 3.6% [175/4898] of remission/mild, 4.9% [45/920] of moderate and 8.8% [23/260] of severe [p < 0.001]; and hospitalization in 13% [649/4898] of remission/mild, 19% [178/920] of moderate and 38% [100/260] of severe [p < 0.001]. Stratified by decade, effect sizes were larger for younger patients. In patients ≤50 years, severe PGA was independently associated with ICU/ventilation/death (aOR 3.27 [1.15-9.30]) and hospitalization (aOR 4.62 [2.83-7.55]). In contrast, severe PGA was not independently associated with COVID-19 outcomes in those older than 50 years.

CONCLUSIONS

Clinically active IBD may be a risk factor for severe COVID-19, particularly in younger patients. IBD disease control, including through medication compliance, and strategies to mitigate the risk of COVID-19 infection amongst patients with active IBD [e.g. distancing, immunization] are key to limit adverse COVID-19 outcomes.

Alterations in microbiota of patients with COVID-19: potential mechanisms and therapeutic interventions

The global coronavirus disease 2019 (COVID-19) pandemic is currently ongoing. It is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A high proportion of COVID-19 patients exhibit gastrointestinal manifestations such as diarrhea, nausea, or vomiting. Moreover, the respiratory and gastrointestinal tracts are the primary habitats of human microbiota and targets for SARS-CoV-2 infection as they express angiotensin-converting enzyme-2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) at high levels. There is accumulating evidence that the microbiota are significantly altered in patients with COVID-19 and post-acute COVID-19 syndrome (PACS). Microbiota are powerful immunomodulatory factors in various human diseases, such as diabetes, obesity, cancers, ulcerative colitis, Crohn’s disease, and certain viral infections. In the present review, we explore the associations between host microbiota and COVID-19 in terms of their clinical relevance. Microbiota-derived metabolites or components are the main mediators of microbiota-host interactions that influence host immunity. Hence, we discuss the potential mechanisms by which microbiota-derived metabolites or components modulate the host immune responses to SARS-CoV-2 infection. Finally, we review and discuss a variety of possible microbiota-based prophylaxes and therapies for COVID-19 and PACS, including fecal microbiota transplantation (FMT), probiotics, prebiotics, microbiota-derived metabolites, and engineered symbiotic bacteria. This treatment strategy could modulate host microbiota and mitigate virus-induced inflammation.

Intestinal Protein Characterisation of SARS-CoV-2 Entry Molecules ACE2 and TMPRSS2 in Inflammatory Bowel Disease (IBD) and Fatal COVID-19 Infection

The coronavirus SARS-CoV-2 contributes to morbidity and mortality mainly as a result of immune-pathology in the lungs. Recent data has shown multi-system involvement with widespread viral tropism. Here we present a detailed intestinal protein characterisation of SARS-Cov-2 entry molecules ACE2 and TMPRSS2 in patients with inflammatory bowel disease ([IBD]; ulcerative colitis [UC] and Crohn's disease [CD]) with age- and sex-matched non-IBD controls, and in those with fatal COVID-19 infection. In our dataset, ACE2 and TMPRSS2 displayed a membrane enterocyte staining in the ileum (due to presence of brush border/microvilli) in contrast to a cytoplasmic pattern in the colon. We also showed a high ACE2/low TMPRSS2 expression pattern in the ileum with a reverse trend in the colon. In UC, colonic ACE2 and TMPRSS2 are cytoplasmic in nature, with significantly higher ACE2 staining intensity compared to non-IBD controls. In inflamed and unaffected IBD mucosa, ileal and colonic enterocyte ACE2 and TMPRSS2 expressions are not modified in the histologic presence of inflammation. We observed immune cells within the lamina propria that expressed ACE2 and TMPRSS2, at higher frequencies in IBD when compared to non-IBD controls. These were identified as plasma cells with multiple myeloma oncogene 1/interferon regulatory factor 4 (MUM1/IRF4) expression. We further analysed the gut histology of six fatal COVID-19 cases, with no difference in colonic and ileal ACE2/TMRPSS2 staining (compared to non-IBD controls) and identified ACE2 + lamina propria plasma cells. Of interest, in this COVID-19 cohort, there was no histologic evidence gut inflammation despite known evidence of viral tropism within the enterocytes. Our data provides evidence for tissue expression of entry molecules ACE2 and TMPRSS2 including a close apposition to plasma cells - both pointing towards a role of the gut in the antecedent immune response to SARS-CoV-2 infection.

Exogenous Chemical Exposure Increased Transcription Levels of the Host Virus Receptor Involving Coronavirus Infection

Virus receptors are highly involved in mediating the entrance of infectious viruses into host cells. Here, we found that typical chemical exposure caused the upregulation of virus receptor mRNA levels. Chemicals with the same structural characteristics can affect the transcription of angiotensin-converting enzyme 2 (ACE2), a dominant receptor of SARS-CoV-2. Some chemicals can also regulate the transcription of ACE2 by similar regulatory mechanisms, such as multilayer biological responses and the crucial role of TATA-box binding protein associated factor 6. The abovementioned finding suggested that chemical mixtures may have a joint effect on the ACE2 mRNA level in the real scenario, where humans are exposed to numerous chemicals simultaneously in daily life. Chemically regulated virus receptor transcription was in a tissue-dependent manner, with the highest sensitivity in pulmonary epithelial cells. Therefore, in addition to genetic factors, exogenous chemical exposure can be an emerging nongenetic factor that stimulates the transcription of virus receptor abundance and may elevate the protein expression. These alterations could ultimately give rise to the susceptibility to virus infection and disease severity. This finding highlights new requirements for sufficient epidemiological data about exposomes on pathogen receptors in the host.

Nationwide COVID-19-EII Study: Incidence, Environmental Risk Factors and Long-Term Follow-Up of Patients with Inflammatory Bowel Disease and COVID-19 of the ENEIDA Registry

We aim to describe the incidence and source of contagion of COVID-19 in patients with IBD, as well as the risk factors for a severe course and long-term sequelae. This is a prospective observational study of IBD and COVID-19 included in the ENEIDA registry (53,682 from 73 centres) between March-July 2020 followed-up for 12 months. Results were compared with data of the general population (National Centre of Epidemiology and Catalonia). A total of 482 patients with COVID-19 were identified. Twenty-eight percent were infected in the work environment, and 48% were infected by intrafamilial transmission, despite having good adherence to lockdown. Thirty-five percent required hospitalization, 7.9% had severe COVID-19 and 3.7% died. Similar data were reported in the general population (hospitalisation 19.5%, ICU 2.1% and mortality 4.6%). Factors related to death and severe COVID-19 were being aged ≥ 60 years (OR 7.1, 95% CI: 1.8-27 and 4.5, 95% CI: 1.3-15.9), while having ≥2 comorbidities increased mortality (OR 3.9, 95% CI: 1.3-11.6). None of the drugs for IBD were related to severe COVID-19. Immunosuppression was definitively stopped in 1% of patients at 12 months. The prognosis of COVID-19 in IBD, even in immunosuppressed patients, is similar to that in the general population. Thus, there is no need for more strict protection measures in IBD.

Transmembrane serine protease 2 and angiotensin-converting enzyme 2 anti-inflammatory receptors for COVID-19/inflammatory bowel diseases treatment

Inflammatory bowel diseases (IBD) refer to a subgroup of chronic, progressive, long-term, and relapsing inflammatory disorders. IBD may spontaneously grow in the colon, and in severe cases may result in tumor lesions such as invasive carcinoma in inflamed regions of the intestine. Recent epidemiological reports indicate that old age and underlying diseases such as IBD contribute to severity and mortality in patients with coronavirus disease 2019 (COVID-19). Currently, the ongoing COVID-19 pandemic caused serious morbidity and mortality worldwide. It has also been shown that the transmembrane serine protease 2 is an essential factor for viral activation and viral engulfment. Generally, viral entry causes a 'cytokine storm' that induces excessive generation of proinflammatory cytokines/chemokines including interleukin (IL)-6, IL-2, IL-7, tumor necrosis factor-α, and interferon-γ. Future research could concentrate on developing inflammatory immunological responses that are efficient to encounter COVID-19. Current analysis elucidates the role of inflammation and immune responses during IBD infection with COVID-19 and provides a list of possible targets for IBD-regulated therapies in particular. Data from clinical, in vitro, and in vivo studies were collected in English from PubMed, Google Scholar, Scopus, and the Cochrane library until May 2021.

Clinical Outcomes of COVID-19 and Impact on Disease Course in Patients with Inflammatory Bowel Disease

BACKGROUND AND AIMS

The impact of COVID-19 has been of great concern in patients with inflammatory bowel disease (IBD) worldwide, including an increased risk of severe outcomes and/or possible flare of IBD. This study aims to evaluate prevalence, outcomes, the impact of COVID-19 in patients with IBD, and risk factors associated with severe COVID-19 or flare of IBD activity.

METHODS

A consecutive cohort of IBD patients who were diagnosed with COVID-19 infection and followed up at the McGill University Health Care Centre was obtained between March 1, 2020, and April 30, 2021. Demographics, comorbidities, IBD (type, treatments, pre- and post-COVID-19 clinical activity, biomarkers, and endoscopic activity), and COVID-19-related outcomes (pneumonia, hospitalization, death, and flare of IBD disease) were analyzed.

RESULTS

A cohort of 3,516 IBD patients was included. 82 patients (2.3%) were diagnosed with COVID-19 infection (median age: 39.0 (IQR 27.8-48.0), 77% with Crohn's disease, 50% were female). The prevalence of COVID-19 infection in IBD patients was significantly lower compared to the general population in Canada and Quebec (3.5% versus 4.3%, p < 0.001). Severe COVID-19 occurred in 6 patients (7.3%); 2 patients (2.4%) died. A flare of IBD post-COVID-19 infection was reported in 8 patients (9.8%) within 3 months. Biologic therapy was held during active COVID-19 infection in 37% of patients. Age ≥55 years (odds ratio (OR): 11.1, 95% CI: 1.8-68.0), systemic corticosteroid use (OR: 4.6, 95% CI: 0.7-30.1), active IBD (OR: 3.8, 95% CI: 0.7-20.8), and comorbidity (OR: 4.9, 95% CI: 0.8-28.6) were factors associated with severe COVID-19. After initial infection, 61% of IBD patients received COVID-19 vaccinations.

CONCLUSION

The prevalence of COVID-19 infection among patients with IBD was lower than that in the general population in Canada. Severe COVID-19, mortality, and flare of IBD were relatively rare, while a large proportion of patients received COVID-19 vaccination. Older age, comorbidities, active IBD disease, and systemic corticosteroid, but not immunosuppressive or biological therapy, were associated with severe COVID-19 infection.

Host Response to SARS-CoV2 and Emerging Variants in Pre-Existing Liver and Gastrointestinal Diseases

Background

Novel coronavirus SARS-CoV2 is evolving continuously with emergence of several variants of increasing transmission capabilities and pandemic potential. Generation of variants occurs through accumulation of mutations due to the RNA nature of viral genome, which is further enhanced by variable selection pressures of this ongoing pandemic. COVID-19 presentations of SARS-CoV2 are mainly pulmonary manifestations with or without mild gastrointestinal (GI) and hepatic symptoms. However, the virus has evolved beyond pulmonary manifestations to multisystem disorder due to systemic inflammation and cytokine storm. Definitive cause of acute or late onset of inflammation, infection in various organs, and host response to emerging variants lacks clarity and needs elucidation. Several studies have reported underlying diseases including diabetes, hypertension, obesity, cardio- and cerebrovascular disorders, and immunocompromised conditions as significant risk factors for severe form of COVID-19. Pre-existing liver and GI diseases are also highly predominant in the population, which can alter COVID-19 outcome due to altered immune status and host response. We aim to review the emerging variants of SARS-CoV2 and host response in patients with pre-existing liver and GI diseases.

Methods

In this review, we have elucidated the emergence and characteristic features of new SARS-CoV2 variants, mechanisms of infection and host immune response, GI and hepatic manifestation with radiologic features of COVID-19, and outcomes in pre-existing liver and GI diseases.

Key Findings

Emerging variants of concern (VOC) have shown increased transmissibility and virulence with severe COVID-19 presentation and mortality. There is a drastic swift of variants from the first wave to the next wave of infections with predominated major VOC including alpha (B.1.1.7, UK), beta (B.1.351, South Africa), gamma (B.1.1.28.1, Brazil), and delta (B1.1.617, India) variants. The mutations in the spike protein of VOC are implicated for increased receptor binding (N501Y, P681R) and immune escape (L452R, E484K/Q, T478K/R) to host response. Pre-existing liver and GI diseases not only have altered tissue expression and distribution of viral entry ACE2 receptor but also host protease TMPRSS2, which is required for both spike protein binding and cleavage to initiate infection. Altered immune status due to pre-existing conditions results in delayed virus clearance or prolonged viremia. Even though GI and hepatic manifestations of SARS-CoV2 are less severe, the detection of virus in patient’s stool indicates GI tropism, replication, and shedding from the GI tract. COVID-19-induced liver injury, acute hepatic decompensation, and incidences of acute-on-chronic liver failure may change the disease outcomes.

Conclusions

The changes in the spike protein of emerging variants, immunomodulation by viral proteins, and altered expression of host viral entry receptor in pre-existing diseases are the key determinants of host response to SARS-CoV2 and its disease outcome.

Molecular Insights into SARS-CoV2-Induced Alterations of the Gut/Brain Axis

For a yet unknown reason, a substantial share of patients suffering from COVID-19 develop long-lasting neuropsychiatric symptoms ranging from cognitive deficits to mood disorders and/or an extreme fatigue. We previously reported that in non-neural cells, angiotensin-1 converting enzyme 2 (ACE2), the gene coding for the SARS-CoV2 host receptor, harbors tight co-expression links with dopa-decarboxylase (DDC), an enzyme involved in the metabolism of dopamine. Here, we mined and integrated data from distinct human expression atlases and found that, among a wide range of tissues and cells, enterocytes of the small intestine express the highest expression levels of ACE2, DDC and several key genes supporting the metabolism of neurotransmitters. Based on these results, we performed co-expression analyses on a recently published set of RNA-seq data obtained from SARS-CoV2-infected human intestinal organoids. We observed that in SARS-CoV2-infected enterocytes, ACE2 co-regulates not only with DDC but also with a specific group of genes involved in (i) the dopamine/trace amines metabolic pathway, (ii) the absorption of microbiota-derived L-DOPA and (iii) the absorption of neutral amino acids serving as precursors to neurotransmitters. We conclude that in patients with long COVID, a chronic infection and inflammation of small intestine enterocytes might be indirectly responsible for prolonged brain alterations.

Impact of COVID-19 on inflammatory bowel disease practice and perspectives for the future

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); since its first description in December 2019, it has rapidly spread to a global pandemic. Specific concerns have been raised concerning patients with inflammatory bowel diseases (IBD), which are chronic autoimmune inflammatory disorders of the gut that frequently require immunosuppressive and biological therapies to control their activity. Accumulating evidence has so far demonstrated that patients with IBD are not at increased risk of contracting severe acute respiratory syndrome coronavirus 2 infection. As for the general population, the identified risk factors for severe COVID-19 course among IBD patients have been established to be advanced age and the presence of comorbidities. Treatment with high-dose corticosteroids has also been associated with an increased risk of death in IBD patients with COVID-19. Information on COVID-19 is constantly evolving, with data growing at a rapid pace. This will guarantee better knowledge and stronger evidence to help physicians in the choice of the best therapeutic approach for each patient, concurrently controlling for the risk of IBD disease under treatment and the risk of COVID-19 adverse outcomes and balancing the two. Moreover, the impact of the enormous number of severe respiratory patients on healthcare systems and facilities has led to an unprecedented redeployment of healthcare resources, significantly impacting the care of patients with chronic diseases. In this newly changed environment, the primary aim is to avoid harm whilst still providing adequate management. Telemedicine has been applied and is strongly encouraged for patients without the necessity of infusion therapy and whose conditions are stable. The severe acute respiratory syndrome coronavirus 2 pandemic has already revolutionized the management of patients with chronic immune-mediated diseases such as IBD. Direct and indirect effects of the COVID-19 pandemic will be present for some time. This is the reason why continuous research, rapid solutions and constantly updated guidelines are of utmost importance. The aim of the present review is, therefore, to point out what has been learned so far as well as to pinpoint the unanswered questions and perspectives for the future.

COVID-19 in gastroenterology: Where are we now? Current evidence on the impact of COVID-19 in gastroenterology

BACKGROUND

The COVID-19 pandemic has created unprecedented challenges in all fields of society with social, economic, and health-related consequences worldwide. In this context, gastroenterology patients and healthcare systems and professionals have seen their routines changed and were forced to adapt, adopting measures to minimize the risk of infection while guaranteeing continuous medical care to chronic patients.

OBJECTIVE

At this point, it is important to evaluate the impact of the pandemic on this field to further improve the quality of the services provided in this context.

METHODS/RESULTS/CONCLUSION

We performed a literature review that summarizes the main aspects to consider in gastroenterology, during the pandemic crisis, and includes a deep discussion on the main changes affecting gastroenterology patients and healthcare systems, anticipating the pandemic recovery scenario with future practices and policies.

Increased colonic expression of ACE2 associates with poor prognosis in Crohn's disease

The host receptor for SARS-CoV-2, angiotensin-converting enzyme 2 (ACE2), is highly expressed in small intestine. Our aim was to study colonic ACE2 expression in Crohn's disease (CD) and non-inflammatory bowel disease (non-IBD) controls. We hypothesized that the colonic expression levels of ACE2 impacts CD course. We examined the expression of colonic ACE2 in 67 adult CD and 14 NIBD control patients using RNA-seq and quantitative (q) RT-PCR. We validated ACE2 protein expression and localization in formalin-fixed, paraffin-embedded matched colon and ileal tissues using immunohistochemistry. The impact of increased ACE2 expression in CD for the risk of surgery was evaluated by a multivariate regression analysis and a Kaplan–Meier estimator. To provide critical support for the generality of our findings, we analyzed previously published RNA-seq data from two large independent cohorts of CD patients. Colonic ACE2 expression was significantly higher in a subset of adult CD patients which was defined as the ACE2-high CD subset. IHC in a sampling of ACE2-high CD patients confirmed high ACE2 protein expression in the colon and ileum compared to ACE2-low CD and NIBD patients. Notably, we found that ACE2-high CD patients are significantly more likely to undergo surgery within 5 years of CD diagnosis, and a Cox regression analysis found that high ACE2 levels is an independent risk factor for surgery (OR 2.17; 95% CI, 1.10–4.26; p = 0.025). Increased intestinal expression of ACE2 is associated with deteriorated clinical outcomes in CD patients. These data point to the need for molecular stratification that can impact CD disease-related outcomes.

Renin-angiotensin system in intestinal inflammation-Angiotensin inhibitors to treat inflammatory bowel diseases?

Inflammatory bowel diseases (IBDs) are chronic disorders of the gastrointestinal tract, which manifest in recurring gastrointestinal inflammation. The current treatment options of IBD are not curative and are lacking in aspects like prevention of fibrosis. New treatment options are needed to fulfil the unmet needs and provide alternatives to drugs with resistances and side effects. Drugs targeting the renin-angiotensin system (RAS), besides being antihypertensive, also possess anti-inflammatory and antifibrotic properties and could offer an inexpensive alternative to control inflammation and fibrosis in the gut. RAS inhibitors have been effective in preventing and alleviating colitis in preclinical studies, but available human data are still sparse. This review outlines the pathophysiological functions of RAS in the gut and summarizes preclinical studies utilizing pharmacological RAS inhibitors in the treatment of experimental colitis. We discuss the alterations in intestinal RAS and the available evidence of the benefits of RAS inhibitors for IBD patients. Retrospective studies comparing IBD patients using ACE inhibitors or angiotensin II receptor blockers have provided optimistic results regarding a milder disease course and fewer hospitalizations and corticosteroid use in patients using RAS inhibitors. Prospective studies are needed to evaluate the effectiveness of these promising medications in the treatment of IBD.

A Dual-Route Perspective of SARS-CoV-2 Infection: Lung- vs. Gut-specific Effects of ACE-2 Deficiency

SARS-CoV-2, primarily considered a respiratory virus, is increasingly recognized as having gastrointestinal aspects based on its presence in the gastrointestinal (GI) tract and feces. SARS-CoV-2 uses as a receptor angiotensin-converting enzyme 2 (ACE-2), a critical member of the renin-angiotensin-aldosterone system (RAAS) involved in the regulation of blood pressure and fluid system. In addition to the systemic endocrine functions, RAAS components are also involved in intracrine and organ-specific local functions. The angiotensin-converting enzyme 2 (ACE-2) is a key component of RAAS and a receptor for SARS-CoV-2. It is expressed in many tissues with gastrointestinal (GI) tract ACE-2 levels far exceeding those in the respiratory tract. SARS-CoV-2 binding to its receptor results in a deficiency of ACE-2 activity in endocrine, intracrine, and local lung and GI tract ACE-2. The local ACE-2 has different organ-specific functions, including hypertension-independent activities; dysregulations of these functions may contribute to multiorgan COVID-19 pathology, its severity, long-term effects, and mortality. We review supporting evidence from this standpoint. Notably, COVID-19 comorbidities involving hypertension, obesity, heart disease, kidney disease, and diabetes are associated with gastrointestinal problems and display ACE-2 deficits. While RAAS inhibitors target both endocrine and intracrine ACE-2 activity, the deficit of the local ACE-2 activity in the lungs and more so in the gut have not been targeted. Consequently, the therapeutic approach to COVID-19 should be carefully reconsidered. Ongoing clinical trials testing oral probiotic bound ACE-2 delivery are promising.

Discovery of a AHR pelargonidin agonist that counter-regulates Ace2 expression and attenuates ACE2-SARS-CoV-2 interaction

The severe acute respiratory syndrome (SARS)-CoV-2 is the pathogenetic agent of Corona Virus Induced Disease (COVID)19. The virus enters the human cells after binding to the angiotensin converting enzyme (ACE)2 receptor in target tissues. ACE2 expression is induced in response to inflammation. The colon expression of ACE2 is upregulated in patients with inflammatory bowel disease (IBD), highlighting a potential risk of intestinal inflammation in promoting viral entry in the human body. Because mechanisms that regulate ACE2 expression in the intestine are poorly understood and there is a need of anti-SARS-CoV-2 therapies, we have settled to investigate whether natural flavonoids might regulate the expression of Ace2 in intestinal models of inflammation. The results of these studies demonstrated that pelargonidin activates the Aryl hydrocarbon Receptor (AHR) in vitro and reverses intestinal inflammation caused by chronic exposure to high fat diet or to the intestinal braking-barrier agent TNBS in a AhR-dependent manner. In these two models, development of colon inflammation associated with upregulation of Ace2 mRNA expression. Colon levels of Ace2 mRNA were directly correlated with Tnf-α mRNA levels. Molecular docking studies suggested that pelargonidin binds a fatty acid binding pocket on the receptor binding domain of SARS-CoV-2 Spike protein. In vitro studies demonstrated that pelargonidin significantly reduces the binding of SARS-CoV-2 Spike protein to ACE2 and reduces the SARS-CoV-2 replication in a concentration-dependent manner. In summary, we have provided evidence that a natural flavonoid might hold potential in reducing intestinal inflammation and ACE2 induction in the inflamed colon in a AhR-dependent manner.

Gastrointestinal Pathology in Samples from Coronavirus Disease 2019 (COVID-19)-Positive Patients

CONTEXT

-Although primarily considered a respiratory illness, coronavirus disease 2019 (COVID-19) can cause gastrointestinal manifestations.

OBJECTIVE

-To evaluate histopathology and in situ hybridization for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in gastrointestinal samples from patients with recent and remote COVID-19.

DESIGN

-Patients with positive SARS-CoV-2 nasopharyngeal tests and a gastrointestinal tissue specimen were included. SARS-CoV-2 in situ hybridization (ISH) was performed on each sample. A subset had SARS-CoV-2 next generation sequencing (NGS) performed.

RESULTS

-Twenty-five patients met inclusion criteria. Five had positive SARS-CoV-2 nasopharyngeal tests within 7 days of their gastrointestinal procedure. Two were ulcerative colitis patients on steroid therapy who lacked typical COVID-19 symptoms. Their colectomies showed severe ulcerative colitis; one demonstrated SARS-CoV-2 by NGS but a negative ISH. Another had an ischemic colon resected as a complication of the COVID-19 course; however, both ISH and NGS were negative. A fourth had a normal-appearing terminal ileum but positive ISH and NGS. The fifth patient had ileal ulcers with SARS-CoV-2 negativity by both modalities. The remaining 20 patients had positive nasopharyngeal tests an average of 53 days prior to procedure. None of their samples demonstrated SARS-CoV-2 ISH positivity, but one was positive on NGS despite a negative nasopharyngeal test.

CONCLUSIONS

-Gastrointestinal findings from SARS-CoV-2-infected patients ranged from normal with virus detected by ISH and NGS, to bowel ischemia secondary to systemic viral effects, without evidence of virus in the tissue. No distinct histologic finding was identified in those with gastrointestinal tissue specimens demonstrating SARS-CoV-2 positivity in this cohort.

Ileal Lactase Expression Associates with Lactase Persistence Genotypes

(1) Background: Lactose digestion depends on persistence genotypes (including rs4988235), the frequency of which exhibits broad geographical variability. However, little is known about the relationship between lactase (LCT) genotypes and intestinal expression of LCT. We aimed to investigate ileal expression of LCT depending on main genetic polymorphisms (rs4988235, rs3754689, rs3739022), age, sex, smoking status, body mass index (BMI), and the expression of other genes; (2) Methods: phenotype, array-based genotype, and ileal mucosal biopsy expression data were obtained from the CEDAR study; (3) Results: analyses included 196 healthy Europeans (53.6% women) aged 53.0 ± 13.6 years with a mean BMI of 25.6 ± 4.2 kg/m², of whom 17.4% were smoking. Ileal LCT expression was mostly independent of age, sex, BMI, or smoking. Rs4988235 homozygous minor allele (GG) associated with lower LCT expression (vs. AG p = 2.2 × 10⁻⁶, vs. AA p = 1.1 × 10⁻⁷). Homozygous major allele of rs3754689 (GG) was related to higher LCT expression (vs. AG p = 1.7 × 10⁻⁵, vs. AA p = 0.0074). Rs3754689 genotype did not modify LCT expression (GG vs. AG p = 0.051) in rs4988235-heterozygous subgroup. Interestingly, CD14, which is a marker of monocytes and macrophages, was the strongest negative transcriptomic correlate of LCT expression (r = −0.57, p_FDR = 1.1 × 10⁻¹⁴); (4) Conclusions: both rs4988235 and rs3754689 associated with ileal LCT expression, which did not seem related to age, sex, smoking, or BMI. The inverse correlation between LCT and CD14 expression in the ileum is striking and requires further investigation.

Human Pluripotent Stem Cell-Derived Intestinal Organoids Model SARS-CoV-2 Infection Revealing a Common Epithelial Inflammatory Response

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leading to coronavirus disease 2019 (COVID-19) usually results in respiratory disease, but extrapulmonary manifestations are of major clinical interest. Intestinal symptoms of COVID-19 are present in a significant number of patients, and include nausea, diarrhea, and viral RNA shedding in feces. Human induced pluripotent stem cell-derived intestinal organoids (HIOs) represent an inexhaustible cellular resource that could serve as a valuable tool to study SARS-CoV-2 as well as other enteric viruses that infect the intestinal epithelium. Here, we report that SARS-CoV-2 productively infects both proximally and distally patterned HIOs, leading to the release of infectious viral particles while stimulating a robust transcriptomic response, including a significant upregulation of interferon-related genes that appeared to be conserved across multiple epithelial cell types. These findings illuminate a potential inflammatory epithelial-specific signature that may contribute to both the multisystemic nature of COVID-19 as well as its highly variable clinical presentation.

COVID-19 illness and autoimmune diseases: recent insights

BACKGROUND

The aim of this review is to explore whether patients with autoimmune diseases (AIDs) were at high risk of infection during the COVID-19 epidemic and how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic affected immune system.

METHODS

A systematic literature search was performed using the foreign databases (NCBI, web of science, EBSCO, ELSEVIER ScienceDirect) and Chinese databases (WanFang, CNKI (China National Knowledge Infrastructure), VIP, CBM) to locate all relevant publications (up to January 10, 2021). The search strategies used Medical Search Headings (MeSH) headings and keywords for "COVID-19" or "SARS-CoV-2" or "coronavirus" and "autoimmune disease".

RESULTS

This review evaluates the effect of SARS-CoV-2 on the immune system through ACE-2 receptor binding as the main pathway for cell attachment and invasion. It is speculated that SARS-COV-2 infection can activate lymphocytes and inflammatory response, which may play a role in the clinical onset of AIDs and also patients were treated with immunomodulatory drugs during COVID-19 outbreak. Preliminary studies suggested that the risk of developing severe forms of COVID-19 in patients with AIDs treated with immunomodulators or biologics might not increase. A large number of samples are needed for further verification, leading to an excessive immune response to external stimuli.

CONCLUSION

The relationship between autoimmune diseases and SARS-CoV-2 infection is complex. During the COVID-19 epidemic, individualized interventions for AIDs should be provided such as Internet-based service.

Risk and outcomes of coronavirus disease in patients with inflammatory bowel disease: A systematic review and meta-analysis

BACKGROUND

The risk of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infection and clinical outcomes of coronavirus disease (COVID-19) in inflammatory bowel disease are unclear.

METHODS

We searched PubMed and Embase with the keywords: inflammatory bowel disease, Crohn's disease, ulcerative colitis and COVID-19, novel coronavirus and SARS-CoV-2. We included studies reporting the frequency of COVID-19 infection and outcomes (hospitalisation, need for intensive care unit care and mortality) in patients with inflammatory bowel disease. We estimated the pooled incidence of COVID-19 in inflammatory bowel disease and comparative risk vis-a-vis the general population. We also estimated the pooled frequency of outcomes and compared them in patients who received and did not receive drugs for inflammatory bowel disease.

RESULTS

Twenty-four studies were included. The pooled incidence rate of COVID-19 per 1000 patients of inflammatory bowel disease and the general population were 4.02 (95% confidence interval [CI, 1.44-11.17]) and 6.59 [3.25-13.35], respectively, with no increase in relative risk (0.47, 0.18-1.26) in inflammatory bowel disease. The relative risk of the acquisition of COVID-19 was not different between ulcerative colitis and Crohn's disease (1.03, 0.62-1.71). The pooled proportion of COVID-19-positive inflammatory bowel disease patients requiring hospitalisation and intensive care unit care was 27.29% and 5.33% while pooled mortality was 4.27%. The risk of adverse outcomes was higher in ulcerative colitis compared to Crohn's disease. The relative risks of hospitalisation, intensive care unit admission and mortality were lower for patients on biological agents (0.34, 0.19-0.61; 0.49, 0.33-0.72 and 0.22, 0.13-0.38, respectively) but higher with steroids (1.99, 1.64-2.40; 3.41, 2.28-5.11 and 2.70, 1.61-4.55) or 5-aminosalicylate (1.59, 1.39-1.82; 2.38, 1.26-4.48 and 2.62, 1.67-4.11) use.

CONCLUSION

SARS-CoV-2 infection risk in patients with inflammatory bowel disease is comparable to the general population. Outcomes of COVID-19-positive inflammatory bowel disease patients are worse in ulcerative colitis, those on steroids or 5-aminosalicylates but outcomes are better with biological agents.

SARS-CoV-2 Vaccination in IBD: Past Lessons, Current Evidence, and Future Challenges

Since the beginning of the pandemic, patients with inflammatory bowel diseases [IBD] have been considered at high risk for infection and complications of COVID-19. IBD patients and patients taking immunosuppressive therapy were excluded from clinical phase III vaccine trials, complicating the assessment of effectiveness of these new vaccines. From past experience we know that adapted vaccination strategies may be appropriate in some IBD patients to optimise immunogenicity. We review current evidence on SARS-CoV-2 vaccination relevant to IBD patients, including immune responses from humoral to cellular, emerging data on new variants, and off-label vaccination schemes. We also identify clinical and scientific knowledge gaps that can be translated into both large-scale population-based studies and targeted vaccine studies to describe the precise immune responses induced by SARS-CoV-2 vaccines in IBD patients. We strongly endorse the recommendation of vaccinating IBD patients to ensure maximal protection from COVID-19 both for the individual and the community.

Intestinal expression of ACE2 in mice with high-fat diet-induced obesity and neonates exposed to maternal high-fat diet

OBJECTIVE

The 2019 novel coronavirus disease (COVID-19) is threatening global health and is especially pronounced in patients with chronic metabolic syndromes. Meanwhile, a significant proportion of patients present with digestive symptoms since angiotensin-converting enzyme 2 (ACE2), which is the receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is highly expressed in the intestine. The aim of this study was to evaluate the effects of a high-fat diet (HFD) and a maternal HFD on the intestinal ACE2 levels in adults and neonates.

METHODS

We examined intestinal ACE2 protein levels in mice with diet-induced obesity (DIO) and neonatal mice exposed to a maternal HFD. We also investigated Ace2 mRNA expression in intestinal macrophages.

RESULTS

Intestinal ACE2 protein levels were increased in DIO mice but decreased in offspring exposed to a maternal HFD compared with chow-fed controls. Ace2 mRNA expression in intestinal macrophages was detected and downregulated in DIO mice. Additionally, higher intestinal ACE2 protein levels were observed in neonates than in adult mice.

CONCLUSIONS

The influence of an HFD on intestinal ACE2 protein levels is opposite in adults and neonates. Macrophages might also be involved in SARS-CoV-2 intestinal infection. These findings provide some clues for the outcomes of patients with COVID-19 with metabolic syndromes.

Angiotensin-converting enzyme 2 and COVID-19: patients, comorbidities, and therapies

On March 11, 2020, the World Health Organization declared coronavirus disease 2019 (COVID-19) a pandemic, and the reality of the situation has finally caught up to the widespread reach of the disease. The presentation of the disease is highly variable, ranging from asymptomatic carriers to critical COVID-19. The availability of angiotensin-converting enzyme 2 (ACE2) receptors may reportedly increase the susceptibility and/or disease progression of COVID-19. Comorbidities and risk factors have also been noted to increase COVID-19 susceptibility. In this paper, we hereby review the evidence pertaining to ACE2's relationship to common comorbidities, risk factors, and therapies associated with the susceptibility and severity of COVID-19. We also highlight gaps of knowledge that require further investigation. The primary comorbidities of respiratory disease, cardiovascular disease, renal disease, diabetes, obesity, and hypertension had strong evidence. The secondary risk factors of age, sex, and race/genetics had limited-to-moderate evidence. The tertiary factors of ACE inhibitors and angiotensin II receptor blockers had limited-to-moderate evidence. Ibuprofen and thiazolidinediones had limited evidence.

Severe acute respiratory syndrome coronavirus 2 infection reaches the human nervous system: How?

Without protective and/or therapeutic agents the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection known as coronavirus disease 2019 is quickly spreading worldwide. It has surprising transmissibility potential, since it could infect all ages, gender, and human sectors. It attacks respiratory, gastrointestinal, urinary, hepatic, and endovascular systems and can reach the peripheral nervous system (PNS) and central nervous system (CNS) through known and unknown mechanisms. The reports on the neurological manifestations and complications of the SARS-CoV-2 infection are increasing exponentially. Herein, we enumerate seven candidate routes, which the mature or immature SARS-CoV-2 components could use to reach the CNS and PNS, utilizing the within-body cross talk between organs. The majority of SARS-CoV-2-infected patients suffer from some neurological manifestations (e.g., confusion, anosmia, and ageusia). It seems that although the mature virus did not reach the CNS or PNS of the majority of patients, its unassembled components and/or the accompanying immune-mediated responses may be responsible for the observed neurological symptoms. The viral particles and/or its components have been specifically documented in endothelial cells of lung, kidney, skin, and CNS. This means that the blood-endothelial barrier may be considered as the main route for SARS-CoV-2 entry into the nervous system, with the barrier disruption being more logical than barrier permeability, as evidenced by postmortem analyses.

COVID-19: biologic and immunosuppressive therapy in gastroenterology and hepatology

The coronavirus disease 2019 (COVID-19) pandemic is an ongoing global health crisis causing major challenges for clinical care in patients with gastrointestinal diseases. Although triggering of anti-viral immune responses is essential for clearance of infection, some patients have severe lung inflammation and multiorgan failure due to marked immune cell dysregulation and cytokine storm syndrome. Importantly, the activation of cytotoxic follicular helper T cells and a reduction of regulatory T cells have a crucial, negative prognostic role. These findings lead to the question of whether immunosuppressive and biologic therapies for gastrointestinal diseases affect the incidence or prognosis of COVID-19 and, thus, whether they should be adjusted to prevent or affect the course of the disease. In this Review, data on the use of such therapies are discussed with a primary focus on inflammatory bowel disease, autoimmune hepatitis and liver transplantation. In particular, the roles of corticosteroids, classic immunosuppressive agents (such as thiopurines and mycophenolate mofetil), small molecules (such as Janus kinase (JAK) inhibitors), and biologic agents (such as tumour necrosis factor (TNF) blockers, vedolizumab and ustekinumab) are reviewed. Finally, the use of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines for the prevention of infection in patients with gastrointestinal diseases and concomitant immunosuppressive or biologic therapy will be discussed.

The Role of Angiotensin Converting Enzyme 2 in Modulating Gut Microbiota, Intestinal Inflammation, and Coronavirus Infection

The role of angiotensin converting enzyme 2 has expanded from regulating the renin angiotensin system to regulating intestinal amino acid homeostasis and the gut microbiome. Recently, angiotensin converting enzyme 2 was identified as a primary receptor for severe acute respiratory syndrome coronaviruses 1 and 2 being expressed in multiple tissues including the luminal surface of the gut. In this brief perspective, we examine the role of angiotensin converting enzyme 2 as the receptor for severe acute respiratory syndrome coronavirus 2 and the impact of coronavirus disease 19 infection on the gut microbiome and on the gut epithelium.

Unraveling the Role of ACE2, the Binding Receptor for SARS-CoV-2, in Inflammatory Bowel Disease

Angiotensin-converting enzyme 2 (ACE2) has been highlighted for its role as a receptor for SARS-CoV-2, responsible for the current COVID-19 pandemic. This review summarizes current knowledge about ACE2 as a multifunctional protein, focusing on its relevance in inflammatory bowel disease (IBD). As an enzyme, ACE2 may be protective in IBD because it favors the counter-regulatory arm of the renin-angiotensin system or deleterious because it metabolizes other anti-inflammatory/repairing elements. Meanwhile, as a receptor for SARS-CoV-2, the impact of ACE2 expression/activity on infection is still under debate because no direct evidence has been reported and, again, both protective and deleterious pathways are possible. Research has shown that ACE2 regulates the expression of the neutral amino acid transporter B0AT1, controlling tryptophan-associated intestinal inflammation and nutritional status. Finally, intact membrane-bound or shed soluble ACE2 can also trigger integrin signaling, modulating the response to anti-integrin biologic drugs used to treat IBD (such as vedolizumab) and fibrosis, a long-term complication of IBD. As such, future studies on ACE2 expression/activity in IBD can improve monitoring of the disease and explore an alternative pharmacological target.

The role of nicotinic receptors in SARS-CoV-2 receptor ACE2 expression in intestinal epithelia

Background

Recent evidence demonstrated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) propagates in intestinal epithelial cells expressing Angiotensin-Converting Enzyme 2 (ACE2), implying that these cells represent an important entry site for the viral infection. Nicotinic receptors (nAChRs) have been put forward as potential regulators of inflammation and of ACE2 expression. As vagus nerve stimulation (VNS) activates nAChRs, we aimed to investigate whether VNS can be instrumental in affecting intestinal epithelial ACE2 expression.

Methods

By using publicly available datasets we qualified epithelial ACE2 expression in human intestine, and assessed gene co-expression of ACE2 and SARS-CoV-2 priming Transmembrane Serine Protease 2 (TMPRSS2) with nAChRs in intestinal epithelial cells. Next, we investigated mouse and human ACE2 expression in intestinal tissues after chronic VNS via implanted devices.

Results

We show co-expression of ACE2 and TMPRSS2 with nAChRs and α7 nAChR in particular in intestinal stem cells, goblet cells, and enterocytes. However, VNS did not affect ACE2 expression in murine or human intestinal tissue, albeit in colitis setting.

Conclusions

ACE2 and TMPRSS2 are specifically expressed in epithelial cells of human intestine, and both are co-expressed with nAChRs. However, no evidence for regulation of ACE2 expression through VNS could be found. Hence, a therapeutic value of VNS with respect to SARS-CoV-2 infection risk through ACE2 receptor modulation in intestinal epithelia could not be established.

COVID-19 and Gastrointestinal Disease: Implications for the Gastroenterologist

BACKGROUND

COVID-19 was initially considered a respiratory disease but the SARS-CoV-2 virus can lead to serious systemic consequences affecting major organs including the digestive system.

SUMMARY

This review brings new clinically important information for the gastroenterologist. This includes: the mechanisms of tissue damage seen with the SARS-CoV-2 virus; the consequences of immunosuppression in patients with inflammatory bowel disease (IBD) and chronic liver disease with the additional risks of decompensation in patients with cirrhosis; the impact of COVID-19 on gastrointestinal emergencies, on gastrointestinal endoscopy, diagnosis and treatments. These highlight the need to understand the clinical pharmacology, toxicology and therapeutic implications of drugs commonly used by gastroenterologists and their links with COVID-19. Key Messages: Any part of the digestive system may be affected by the SARS-CoV-2 virus, and those with pre-existing disease are at greatest risk of adverse outcomes. The risk for drug-drug interactions is considerable in patients seriously ill with COVID-19 who often require mechanical ventilation and life support. Some repurposed drugs used against SARS-CoV-2 can cause or aggravate some of the COVID-19-related gastrointestinal symptoms and can also induce liver injury. Ongoing clinical studies will hopefully identify effective drugs with a more favourable risk-benefit ratio than many initially tried treatments.

Intestinal Receptor of SARS-CoV-2 in Inflamed IBD Tissue Seems Downregulated by HNF4A in Ileum and Upregulated by Interferon Regulating Factors in Colon

BACKGROUND

Patients with inflammatory bowel disease [IBD] are considered immunosuppressed, but do not seem more vulnerable for COVID-19. Nevertheless, intestinal inflammation has shown to be an important risk factor for SARS-CoV-2 infection and prognosis. Therefore, we investigated the role of intestinal inflammation on the viral intestinal entry mechanisms, including ACE2, in IBD.

METHODS

We collected inflamed and uninflamed mucosal biopsies from Crohn's disease [CD] [n = 193] and ulcerative colitis [UC] [n = 158] patients, and from 51 matched non-IBD controls for RNA sequencing, differential gene expression, and co-expression analysis. Organoids from UC patients were subjected to an inflammatory mix and processed for RNA sequencing. Transmural ileal biopsies were processed for single-cell [sc] sequencing. Publicly available colonic sc-RNA sequencing data, and microarrays from tissue pre/post anti-tumour necrosis factor [TNF] therapy, were analysed.

RESULTS

In inflamed CD ileum, ACE2 was significantly decreased compared with control ileum [p = 4.6E-07], whereas colonic ACE2 was higher in inflamed colon of CD/UC compared with control [p = 8.3E-03; p = 1.9E-03]. Sc-RNA sequencing confirmed this ACE2 dysregulation and exclusive epithelial ACE2 expression. Network analyses highlighted HNF4A as key regulator of ileal ACE2, and pro-inflammatory cytokines and interferon regulating factors regulated colonic ACE2. Inflammatory stimuli upregulated ACE2 in UC organoids [p = 1.7E-02], but not in non-IBD controls [p = 9.1E-01]. Anti-TNF therapy restored colonic ACE2 regulation in responders.

CONCLUSIONS

Intestinal inflammation alters SARS-CoV-2 coreceptors in the intestine, with opposing dysregulations in ileum and colon. HNF4A, an IBD susceptibility gene, seems an important upstream regulator of ACE2 in ileum, whereas interferon signalling might dominate in colon.

SARS-CoV-2 and Nervous System - Neurological Manifestations in Patients With COVID-19: A Systematic Review

Coronavirus (CoV) is a virus infectious disease with a considerable spectrum of clinical presentations. Symptoms ranged from asymptomatic infection to severe pneumonia that may lead to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and several clinical complications. Neurologic symptoms related to CoV have been described recently in the literature. The relationship between SARS-CoV-2 and the central nervous system (CNS) is still not clear. This review aimed to reveal the current knowledge regarding CNS manifestation in SARS-CoV-2. A systematic literature review was carried out to identify the particularities of coronavirus disease 2019 (COVID-19) in patients with CNS involvement, using the PubMed database between January 1, 2020 and April 30, 2020. Conference papers, reviews, published letters, editorials, studies in pregnant women and children, and studies only reporting on a specific factor were excluded. An initial search included as many as 83 articles. Out of the 83 screened articles, 32 were selected for full-text review. Sixteen studies were excluded because they did not analyze nervous system involvement in SARS-CoV-2 infection. Thus, 16 papers were included in this review. There were three retrospective studies and 13 case reports/series of cases. Data from the current literature reveal that patients who suffer from a severe illness have more CNS involvement, neurological symptoms (i.e., dizziness, headache) and an association with strokes. The severe patients had higher D-dimer and C-reactive protein levels than non-severe patients and presented multiple organ involvement, such as serious liver, kidney and muscle damage.