Pathogenesis of the inflammatory bowel disease in context of SARS-COV-2 infection

Impact of COVID-19 on Pediatric Inflammatory Bowel Diseases-From Expectations to Reality

Viral infections have always been considered a threat to global health, with numerous outbreaks across time. Despite the relative recent experience with coronavirus-associated diseases such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), severe acute respiratory syndrome-2's (SARS-CoV-2) continuous evolution displays a different behavior. With a tropism for both respiratory and digestive mucosa, coronavirus disease 2019 (COVID-19) and inflammatory bowel disease (IBD) seem to share a particular common background. Current literature offers evidence that viral alteration of the immune system, inflammatory intestinal tissue damage, increased intestinal permeability, incomplete viral clearance with viral antigen persistence, and intestinal dysbiosis, might explain SARS-CoV-2-IBD relationship in terms of etiopathogenesis and evolution. The hyperinflammatory state that both entities have in common explains the lack of success of current IBD therapy, raising the need for new personalized therapeutic options, with better outcomes for IBD and COVID-19 as well. This review aims to summarize the current available data on pediatric IBD evolution, management, and outcomes in the post-COVID period, with an emphasis on the particular aspects of the SARS-CoV-2-IBD relationship in children.

Delivery Strategies of Probiotics from Nano- and Microparticles: Trends in the Treatment of Inflammatory Bowel Disease-An Overview

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder, most known as ulcerative colitis (UC) and Crohn's disease (CD), that affects the gastrointestinal tract (GIT), causing considerable symptoms to millions of people around the world. Conventional therapeutic strategies have limitations and side effects, prompting the exploration of innovative approaches. Probiotics, known for their potential to restore gut homeostasis, have emerged as promising candidates for IBD management. Probiotics have been shown to minimize disease symptoms, particularly in patients affected by UC, opening important opportunities to better treat this disease. However, they exhibit limitations in terms of stability and targeted delivery. As several studies demonstrate, the encapsulation of the probiotics, as well as the synthetic drug, into micro- and nanoparticles of organic materials offers great potential to solve this problem. They resist the harsh conditions of the upper GIT portions and, thus, protect the probiotic and drug inside, allowing for the delivery of adequate amounts directly into the colon. An overview of UC and CD, the benefits of the use of probiotics, and the potential of micro- and nanoencapsulation technologies to improve IBD treatment are presented. This review sheds light on the remarkable potential of nano- and microparticles loaded with probiotics as a novel and efficient strategy for managing IBD. Nonetheless, further investigations and clinical trials are warranted to validate their long-term safety and efficacy, paving the way for a new era in IBD therapeutics.

A Case Series of New-Onset Ulcerative Colitis Following Recent Diagnosis of COVID-19

There have been only 2 reported cases of new-onset ulcerative colitis in pediatrics following acute coronavirus disease 2019 (COVID-19). We are reporting a case series of 3 adolescent female patients, 2 of whom were vaccinated against COVID-19, who developed new-onset ulcerative colitis following a recent diagnosis of COVID-19 infections at a singular pediatric hospital. This case series should be an impetus to clinicians who have pediatric patients with persistent symptoms of hematochezia, diarrhea, and abdominal pain following acute COVID-19 infection to consider further workup for inflammatory bowel disease.

SARS-CoV-2 Gut-Targeted Epitopes: Sequence Similarity and Cross-Reactivity Join Together for Molecular Mimicry

The gastrointestinal tract can be heavily infected by SARS-CoV-2. Being an auto-immunogenic virus, SARS-CoV-2 represents an environmental factor that might play a role in gut-associated autoimmune diseases. However, molecular mimicry between the virus and the intestinal epitopes is under-investigated. The present study aims to elucidate sequence similarity between viral antigens and human enteric sequences, based on known cross-reactivity. SARS-CoV-2 epitopes that cross-react with human gut antigens were explored, and sequence alignment was performed against self-antigens implicated in enteric autoimmune conditions. Experimental SARS-CoV-2 epitopes were aggregated from the Immune Epitope Database (IEDB), while enteric antigens were obtained from the UniProt Knowledgebase. A Pairwise Local Alignment tool, EMBOSS Matcher, was employed for the similarity search. Sequence similarity and targeted cross-reactivity were depicted between 10 pairs of immunoreactive epitopes. Similar pairs were found in four viral proteins and seven enteric antigens related to ulcerative colitis, primary biliary cholangitis, celiac disease, and autoimmune hepatitis. Antibodies made against the viral proteins that were cross-reactive with human gut antigens are involved in several essential cellular functions. The relationship and contribution of those intestinal cross-reactive epitopes to SARS-CoV-2 or its potential contribution to gut auto-immuno-genesis are discussed.

[Inflammatory bowel disease during the COVID-19 pandemic: manifestations and management]

The COVID-19 pandemic is significantly affecting the lives of patients with inflammatory bowel disease (IBD). Those affected and their relatives have numerous questions about the risk of the disease, the course of a possible SARS-CoV-2 infection or the influence of CED-specific therapy on these. Many IBD patients also have additional questions about the safety and effectiveness of a vaccination against SARS-CoV-2. The aim of this review is to summarize the latest findings on COVID-19 and IBD, but also to discuss vaccine response (humoral/cellular), the influence of ongoing therapy on the vaccine response as well as the frequency of side effects and the importance of booster immunizations and to create an evidence-based basis for discussion with patients.

An older patient with active ulcerative colitis and coronavirus disease 2019 (COVID-19) pneumonia successfully treated with the combination of anti-TNFα therapy and azathioprine

A 77-year-old patient with ulcerative colitis (UC) was transferred to our department because of worsening bloody diarrhea and abdominal pain, which was consistent with a UC flare. Two days after admission, she complained of cough and high fever. The polymerase chain reaction (PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was positive, and a computed tomography showed pneumonia in the left lobe, consistent with coronavirus disease 2019 (COVID-19) pneumonia. However, frequent bloody diarrhea and abdominal pain due to the UC flare persisted; therefore, an additional immunosuppressive agent needed to be considered. We initiated infliximab biosimilar (IFX-BS), and her abdominal symptoms improved. However, they deteriorated after the second IFX-BS infusion. After confirming that the patient was negative for SARS-CoV-2 by PCR, we administered a combination of azathioprine and IFX-BS. The combination treatment improved her intestinal symptoms without worsening COVID-19 pneumonia. She has remained in remission for over a year since her discharge.

Functional analysis of the cystatin A gene response to SGIV infection in orange-spotted grouper, Epinephelus coioides

Cystatin A (CyA), an inhibitor of cysteine protease, was widely studied in immune defense and cancer therapy. However, the function of CyA and its potential molecular mechanism during virus infection in fish remain unknown. In our study, we cloned the open reading frame (ORF) of CyA homology from orange-spotted grouper (Ec-CyA) consisting of 303 nucleotides and encoding a 101-amino acid protein. Ec-CyA included two conserved sequences containing one N-terminal glycine fragment and one QXVXG sequence (48aa-52aa) without the signal peptide. Tissue distribution analysis showed that Ec-CyA was highly expressed in spleen and head kidney. Moreover, further analysis indicated that the expression of Ec-CyA increased during SGIV simulation in grouper spleen (GS) cells. Subcellular localization assay demonstrated that Ec-CyA was mainly distributed in cytoplasm in GS cells. Overexpressed Ec-CyA promoted the mRNA level of viral genes MCP, VP19 and LITAF. Meanwhile, SGIV-induced apoptosis in fat head minnow (FHM) cells was facilitated, as well as the activation of caspase-3/7, caspase-9. In addition, Ec-CyA overexpression down-regulated the expression of interferon (IFN) related molecules including ISG15, IFN, IRF3, MAVS, MyD88, TRAF6 and up-regulated proinflammatory factors such as IL-1β, IL-8 and TNF-α. At the same time, Ec-CyA-overexpressing inhibited the activity of IFN and ISRE promoter, but induced NF-κB promoter activity by luciferase reporter gene assay. In summary, our findings suggested that Ec-CyA was involved in innate immune response and played a key role in DNA virus infection.

Functional analysis of the Cystatin F gene response to SGIV infection in orange-spotted grouper, Epinephelus coioides

Cystatin F (CyF), an inhibitor of cysteine protease, was widely studied in immune defense and cancer therapy. However, the function of CyF and its latent molecular mechanism during virus infection in fish remain vacant. In our research, we cloned the open reading frame (ORF) of CyF homology from orange-spotted grouper (Ec-CyF) consisting of 342 nucleotides and encoding a 114-amino acid protein. Ec-CyF included two cystatins family sequences containing one KXVXG sequence without the signal peptide, and a hairpin ring containing proline and tryptophan (PW). Tissue distribution analysis indicated that Ec-CyF was highly expressed in spleen and head kidney. Besides, further analysis showed that the expression of Ec-CyF increased during SGIV infection in grouper spleen (GS) cells. Subcellular localization assay demonstrated that Ec-CyF was mainly distributed in cytoplasm in GS cells. Overexpressed Ec-CyF demoted the mRNA level of viral genes MCP, VP19 and LITAF. Meanwhile, SGIV-induced apoptosis in fat head minnow (FHM) cells was impeded, as well as the restraint of caspase 3/7 and caspase 8. In addition, Ec-CyF overexpression up-regulated the expression of IFN related molecules including ISG15, IFN, IFP35, IRF3, IRF7, MYD88 and down-regulated proinflammatory factors such as IL-1β, IL-8 and TNF-α. At the same time, Ec-CyF-overexpressing increased the activity of IFN3 and ISRE promoter, but impeded NF-κB promoter activity by luciferase reporter gene assay. In summary, our findings suggested that Ec-CyF was involved in innate immunity response and played a key role in DNA virus infection.

Functional Analysis of the Cathepsin D Gene Response to SGIV Infection in the Orange-Spotted Grouper, Epinephelus coioides

(1) Background: Lysosomal aspartic protease Cathepsin D (CD) is a key regulator and signaling molecule in various biological processes including activation and degradation of intracellular proteins, the antigen process and programmed cell death. However, the function of fish CD in virus infection remains largely unknown. (2) Methods: The functions of the CD gene response to SGIV infection was determined with light microscopy, reverse transcription quantitative PCR, Western blot and flow cytometry. (3) Results: In this study, Ec-Cathepsin D (Ec-CD) was cloned and identified from the orange-spotted grouper, Epinephelus coioides. The open reading frame (ORF) of Ec-CD consisted of 1191 nucleotides encoding a 396 amino acid protein with a predicted molecular mass of 43.17 kDa. Ec-CD possessed typical CD structural features including an N-terminal signal peptide, a propeptide region and a mature domain including two glycosylation sites and two active sites, which were conserved in other CD sequences. Ec-CD was predominantly expressed in the spleen and kidneys of healthy groupers. A subcellular localization assay indicated that Ec-CD was mainly distributed in the cytoplasm. Ec-CD expression was suppressed by SGIV stimulation and Ec-CD-overexpressing inhibited SGIV replication, SGIV-induced apoptosis, caspase 3/8/9 activity and the activation of reporter gene p53 and activating protein-1 (AP-1) in vitro. Simultaneously, Ec-CD overexpression obviously restrained the activated mitogen-activated protein kinase (MAPK) pathways, including extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK). In addition, Ec-CD overexpression negatively regulated the transcription level of pro-inflammatory cytokines and activation of the NF-κB promotor. (4) Conclusions: Our findings revealed that the Ec-CD possibly served a function during SGIV infection.

Probiotics: Protecting Our Health from the Gut

The gut microbiota (GM) comprises billions of microorganisms in the human gastrointestinal tract. This microbial community exerts numerous physiological functions. Prominent among these functions is the effect on host immunity through the uptake of nutrients that strengthen intestinal cells and cells involved in the immune response. The physiological functions of the GM are not limited to the gut, but bidirectional interactions between the gut microbiota and various extraintestinal organs have been identified. These interactions have been termed interorganic axes by several authors, among which the gut-brain, gut-skin, gut-lung, gut-heart, and gut-metabolism axes stand out. It has been shown that an organism is healthy or in homeostasis when the GM is in balance. However, altered GM or dysbiosis represents a critical factor in the pathogenesis of many local and systemic diseases. Therefore, probiotics intervene in this context, which, according to various published studies, allows balance to be maintained in the GM, leading to an individual's good health.

De Novo Pediatric Ulcerative Colitis Triggered by SARS-CoV-2 Infection: a Tale of 2 Sisters

We present a report of 2 sisters who developed acute onset hematochezia concurrently with SARS-CoV-2 infection. One patient recovered completely, whereas the sibling developed chronic symptoms leading to a diagnosis of ulcerative colitis requiring biologic therapy.

Protective Effect of Prim-O-Glucosylcimifugin on Ulcerative Colitis and Its Mechanism

Intestinal epithelial immune dysfunction or imbalance in the homeostasis of intestinal flora can lead to the occurrence or exacerbation of ulcerative colitis (UC). Prim-O-glucosylcimifugin (POG) is an extract of Chinese traditional medicine (TCM) Saposhnikov, which has analgesic, anti-inflammatory, and antioxidant effects. The present work discussed how the POG alternated ulcerative colitis (UC) along with its underlying mechanism. This was clarified by performing animal studies in a mice model, wherein UC was induced by dextran sulfate sodium (DSS). In vivo studies have found that POG increased clinical score, colonic length, and weight of mice in the ulcerative colitis model. It repaired the pathological injury of an intestinal mucosa within mice while inhibiting the inflammatory factor levels such as IL-1β, TNF-α, and IL-6. Meanwhile, by16SrDNA sequencing analysis, it was found that POG regulated the richness of intestinal microbiota structure and repaired the intestinal immune barrier by upregulating the expression levels of tight junction proteins Occludin, Claudin-3, and ZO-1. To further confirm the above results, we found in in vitro studies that POG also protected lipopolysaccharide- (LPS-) induced RAW264.7 cells. POG dramatically suppressed inflammatory factor production (including TNF-α, IL-1β, and IL-6) within LPS-treated RAW264.7 cells by inhibiting the activation of ERK1/2, AKT, JNK1/2, IκB-α, P38, and P65 phosphorylation. In conclusion, POG plays a protective role against UC by inhibiting the activation of pro-inflammatory signaling pathways MAPK, AKT, and NF-κB; repairing the integrity of the intestinal barrier; and regulating the diversity and abundance of intestinal flora.

Host-Viral Interactions in the Pathogenesis of Ulcerative Colitis

Ulcerative colitis is characterized by relapsing and remitting colonic mucosal inflammation. During the early stages of viral infection, innate immune defenses are activated, leading to the rapid release of cytokines and the subsequent initiation of downstream responses including inflammation. Previously, intestinal viruses were thought to be either detrimental or neutral to the host. However, persisting viruses may have a role as resident commensals and confer protective immunity during inflammation. On the other hand, the dysregulation of gut mucosal immune responses to viruses can trigger excessive, pathogenic inflammation. The purpose of this review is to discuss virus-induced innate immune responses that are at play in ulcerative colitis.