COVID-19-Induced Thrombosis in Patients without Gastrointestinal Symptoms and Elevated Fecal Calprotectin: Hypothesis Regarding Mechanism of Intestinal Damage Associated with COVID-19

From diversity to disease: unravelling the role of enteric glial cells

Enteric glial cells (EGCs) are an essential component of the enteric nervous system (ENS) and play key roles in gastrointestinal development, homeostasis, and disease. Derived from neural crest cells, EGCs undergo complex differentiation processes regulated by various signalling pathways. Being among the most dynamic cells of the digestive system, EGCs react to cues in their surrounding microenvironment and communicate with various cell types and systems within the gut. Morphological studies and recent single cell RNA sequencing studies have unveiled heterogeneity among EGC populations with implications for regional functions and roles in diseases. In gastrointestinal disorders, including inflammatory bowel disease (IBD), infections and cancer, EGCs modulate neuroplasticity, immune responses and tumorigenesis. Recent evidence suggests that EGCs respond plastically to the microenvironmental cues, adapting their phenotype and functions in disease states and taking on a crucial role. They exhibit molecular abnormalities and alter communication with other intestinal cell types, underscoring their therapeutic potential as targets. This review delves into the multifaceted roles of EGCs, particularly emphasizing their interactions with various cell types in the gut and their significant contributions to gastrointestinal disorders. Understanding the complex roles of EGCs in gastrointestinal physiology and pathology will be crucial for the development of novel therapeutic strategies for gastrointestinal disorders.

Elevated level of circulating calprotectin correlates with severity and high mortality in patients with COVID-19

BACKGROUND

Patients with coronavirus disease-2019 (COVID-19) are characterized by hyperinflammation. Calprotectin (S100A8/S100A9) is a calcium- and zinc-binding protein mainly secreted by neutrophilic granulocytes or macrophages and has been suggested to be correlated with the severity and prognosis of COVID-19.

AIM

To thoroughly evaluate the diagnostic and prognostic utility of calprotectin in patients with COVID-19 by analyzing relevant studies.

METHODS

PubMed, Web of Science, and Cochrane Library were comprehensively searched from inception to August 1, 2023 to retrieve studies about the application of calprotectin in COVID-19. Useful data such as the level of calprotectin in different groups and the diagnostic efficacy of this biomarker for severe COVID-19 were extracted and aggregated by using Stata 16.0 software.

RESULTS

Fifteen studies were brought into this meta-analysis. First, the pooled standardized mean differences (SMDs) were used to estimate the differences in the levels of circulating calprotectin between patients with severe and non-severe COVID-19. The results showed an overall estimate of 1.84 (95% confidence interval [CI]: 1.09-2.60). Diagnostic information was extracted from 11 studies, and the pooled sensitivity and specificity of calprotectin for diagnosing severe COVID-19 were 0.75 (95% CI: 0.64-0.84) and 0.88 (95% CI: 0.79-0.94), respectively. The AUC was 0.89 and the pooled DOR was 18.44 (95% CI: 9.07-37.51). Furthermore, there was a strong correlation between elevated levels of circulating calprotectin and a higher risk of mortality outcomes in COVID-19 patients (odds ratio: 8.60, 95% CI: 2.17-34.12; p < 0.1).

CONCLUSION

This meta-analysis showed that calprotectin was elevated in patients with severe COVID-19, and this atypical inflammatory cytokine might serve as a useful biomarker to distinguish the severity of COVID-19 and predict the prognosis.

SARS-CoV-2 Altered Hemorheological and Hematological Parameters during One-Month Observation Period in Critically Ill COVID-19 Patients

Hematological and hemorheological parameters are known to be altered in COVID-19; however, the value of combined monitoring in order to deduce disease severity is only scarcely examined. A total of 44 acute SARS-CoV-2-infected patients (aCOV) and 44 age-matched healthy controls (Con) were included. Blood of aCOV was sampled at admission (T0), and at day 2 (T2), day 5 (T5), day 10 (T10), and day 30 (T30) while blood of Con was only sampled once. Inter- and intra-group differences were calculated for hematological and hemorheological parameters. Except for mean cellular volume and mean cellular hemoglobin, all blood cell parameters were significantly different between aCOV and Con. During the acute disease state (T0-T5), hematological and hemorheological parameters were highly altered in aCOV; in particular, anemic conditions and increased immune cell response/inflammation, oxidative/nitrosative stress, decreased deformability, as well as increased aggregation, were observed. During treatment and convalescence until T30, almost all abnormal values of aCOV improved towards Con values. During the acute state of the COVID-19 disease, the hematological, as well as the hemorheological system, show fast and potentially pathological changes that might contribute to the progression of the disease, but changes appear to be largely reversible after four weeks. Measuring RBC deformability and aggregation, as well as oxidative stress induction, may be helpful in monitoring critically ill COVID-19 patients.

Postpartum Multiple Colon Perforation after Cesarean Section in COVID-19 Patients: A Case Series

Introduction

Gastrointestinal symptoms are present in 50% of polymerase chain reaction (PCR)-positive COVID-19 patients. In addition, bowel abnormalities are a common finding of COVID-19, and bowel-wall disorder is reported in 31% of computed tomography images of COVID-19 patients.

Case History

We report three postpartum cases with colon perforation after Cesarean section and positive PCR for SARS-CoV-2-RNA and during the main peak of COVID-19 pandemic, who were managed by early detection, laparotomy, and effective treatment and were discharged and followed up.

Conclusion

A colonic perforation could be considered as one of the causes of abdominal pain especially in women with a past surgical history as well as patients with infectious diseases such as COVID-19. Therefore, abdominal and pelvic ultrasound or x-ray was strongly recommended for postpartum women with abnormal abdominal distension, gastrointestinal symptoms, and pain to prevent possible fetal complications.

Role of fecal calprotectin as a hypoxic intestinal damage biomarker in COVID-19 patients

Background

Gastrointestinal manifestations of coronavirus disease 2019 (COVID-19) appear to be substantial. Fecal calprotectin is a promising biomarker in COVID-19 associated gastrointestinal inflammation; however, its role in the severity of COVID-19 remains limited. We conducted a study to analyze the relationship between the severity of COVID-19 and hypoxic intestinal damage.

Methods

We assessed the severity of 44 hospitalized COVID-19 pneumonia patients based on the PaO2/FiO2 (P/F) ratio. Inflammatory markers were measured from blood samples, and fecal calprotectin was obtained from stool samples.

Results

Median levels of fecal calprotectin in COVID-19 patients involved in this study (n = 44) were found to be markedly elevated along with the severity of hypoxemia, as seen in the non-acute respiratory distress syndrome (ARDS) group 21.4 µg/g (5.2–120.9), mild ARDS 54.30 µg/g (5.2–1393.7), moderate ARDS 169.6 µg/g (43.4–640.5), and severe ARDS 451.6 µg/g (364.5–538.6). We also found significant differences in fecal calprotectin levels based on the severity of ARDS (P < 0.001), and although the patients were divided into ARDS and non-ARDS groups (P < 0.001). Furthermore, we found a strong negative correlation between the P/F ratio and fecal calprotectin levels (r = − 0.697, P < 0.001).

Conclusion

Our findings support the potential role of fecal calprotectin as a biomarker of intestinal inflammation in COVID-19 as a consequence of hypoxic intestinal damage and as suggested by the reduced P/F ratio.

Acute Gastrointestinal Injury and Feeding Intolerance as Prognostic Factors in Critically Ill COVID-19 Patients

BACKGROUND

Although acute gastrointestinal injury (AGI) and feeding intolerance (FI) are known independent determinants of worse outcomes and high mortality in intensive care unit (ICU) patients, the incidence of AGI and FI in critically ill COVID-19 patients and their prognostic importance have not been thoroughly studied.

METHODS

We reviewed 218 intubated patients at Stony Brook University Hospital and stratified them into three groups based on AGI severity, according to data collected in the first 10 days of ICU course. We used chi-square test to compare categorical variables such as age and sex and two-sample t-test or Mann-Whitney U-tests for continuous variables, including important laboratory values. Cox proportional hazards regression models were utilized to determine whether AGI score was an independent predictor of survival, and multivariable analysis was performed to compare risk factors that were deemed significant in the univariable analysis. We performed Kaplan-Meier survival analysis based on the AGI score and the presence of FI.

RESULTS

The overall incidence of AGI was 95% (45% AGI I/II, 50% AGI III/IV), and FI incidence was 63%. Patients with AGI III/IV were more likely to have prolonged mechanical ventilation (22 days vs 16 days, P-value <0.002) and higher mortality rate (58% vs 28%, P-value <0.001) compared to patients with AGI 0/I/II. This was confirmed with multivariable analysis which showed that AGI score III/IV was an independent predictor of higher mortality (AGI III/IV vs AGI 0/I/II hazard ratio (HR), 2.68; 95% confidence interval (CI), 1.69-4.25; P-value <0.0001). Kaplan-Meier survival analysis showed that both AGI III/IV and FI (P-value <0.001) were associated with worse outcomes. Patients with AGI III/IV had higher daily and mean D-dimer and CRP levels compared to AGI 0/I/II (P-value <0.0001).

CONCLUSIONS

The prevalence of AGI and FI among critically ill COVID-19 patients was high. AGI grades III/IV were associated with higher risk for prolonged mechanical ventilation and mortality compared to AGI 0/I/II, while it also correlated with higher D-dimer and C-reactive protein (CRP) levels. FI was independently associated with higher mortality. The development of high-grade AGI and FI during the first days of ICU stay can serve as prognostic tools to predict outcomes in critically ill COVID-19 patients.

Acute Mesenteric Ischemia in COVID-19 Patients

Acute mesenteric ischemia is a rare but extremely severe complication of SARS-CoV-2 infection. The present review aims to document the clinical, laboratory, and imaging findings, management, and outcomes of acute intestinal ischemia in COVID-19 patients. A comprehensive search was performed on PubMed and Web of Science with the terms “COVID-19” and “bowel ischemia” OR “intestinal ischemia” OR “mesenteric ischemia” OR “mesenteric thrombosis”. After duplication removal, a total of 36 articles were included, reporting data on a total of 89 patients, 63 being hospitalized at the moment of onset. Elevated D-dimers, leukocytosis, and C reactive protein (CRP) were present in most reported cases, and a contrast-enhanced CT exam confirms the vascular thromboembolism and offers important information about the bowel viability. There are distinct features of bowel ischemia in non-hospitalized vs. hospitalized COVID-19 patients, suggesting different pathological pathways. In ICU patients, the most frequently affected was the large bowel alone (56%) or in association with the small bowel (24%), with microvascular thrombosis. Surgery was necessary in 95.4% of cases. In the non-hospitalized group, the small bowel was involved in 80%, with splanchnic veins or arteries thromboembolism, and a favorable response to conservative anticoagulant therapy was reported in 38.4%. Mortality was 54.4% in the hospitalized group and 21.7% in the non-hospitalized group (p < 0.0001). Age over 60 years (p = 0.043) and the need for surgery (p = 0.019) were associated with the worst outcome. Understanding the mechanisms involved and risk factors may help adjust the thromboprophylaxis and fluid management in COVID-19 patients.

Low Transferrin Levels Predict Heightened Inflammation in COVID-19 Patients: New Insights

Objectives

Mounting evidence links hyperinflammation in gravely ill patients to low serum iron levels and hyperferritinemia. However, little attention has been paid to other iron-associated markers such as transferrin. The aim of this study was to investigate the association of different iron parameters in severe COVID-19 and their relation to disease severity.

Subjects and methods

This study involved 73 hospitalized patients with positive test results for SARS-CoV-2. Patients were classified into two groups according to symptom severity: mild and severe. Blood levels of anti–SARS-CoV-2 antibodies, interleukin 6 (IL-6), C-reactive protein (CRP), and iron-related biomarkers were measured.

Results

The results revealed a significant increase in IL-6, CRP, and ferritin levels and decreased transferrin and iron levels in severe COVID-19. Transferrin negatively predicted variations in IgM and IgG levels (P < 0.001), as well as 34.4% and 36.6% increase in IL-6 and CRP levels, respectively (P < 0.005). Importantly, transferrin was the main negative predictor of ferritin levels, determining 22.7% of serum variations (P < 0.001).

Conclusion

Reduced serum transferrin and iron levels, along with the increased CRP and high ferritin, were strongly associated with the heightened inflammatory and immune state in COVID-19. Transferrin can be used as a valuable predictor of increased severity and progression of the disease.

Pathogenesis and Mechanism of Gastrointestinal Infection With COVID-19

As a new infectious disease, COVID-19 is spread through the respiratory tract in most cases. Its source and pathological mechanism are not clear. The most common clinical feature is pulmonary infection. Also, a lot patients have gastrointestinal symptoms. Angiotensin-converting enzyme 2 (ACE2) is a functional cellular receptor for SARS-CoV-2, which is like SARS-CoV, a coronavirus associated with severe acute respiratory syndrome (SARS) outbreak in 2003. The tissues and cells expressing ACE2 are potential targets for SARS-CoV-2 infection, and the high expression of ACE2 in intestinal epithelial cells marks that SARS-CoV-2 may directly infect intestinal epithelial cells. Recent studies also suggest that SARS-CoV-2 existed and replicated in intestinal environment for a long time. The interaction between SARS-CoV-2 and RAS system leads to the decrease of local anti-inflammatory ability. The virus cycle leads to excessive imbalance of immune response and cytokine release. The downregulation of ACE2 after viral infection leads to gastrointestinal dysfunction. The above are the causes of gastrointestinal symptoms. Here, we reviewed the possible causes and mechanisms of gastrointestinal symptoms caused by COVID-19. Additionally, we discussed the influence of gastrointestinal symptoms on the prognosis of patients.

The Impact of COVID-19 in Gastroenterology and Hepatology

The 2019 coronavirus disease (COVID-19), an airborne infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in a global pandemic. SARS-CoV-2 relies on the angiotensin-converting enzyme 2 receptor for cellular entry and the abundance of this receptor in the gastrointestinal (GI) tract may help explain the GI manifestations, including dysgeusia, nausea, vomiting, diarrhea, and abdominal pain, present in over 40% of infected patients. GI tract involvement also raises the concern for oral-fecal transmission which is poorly understood. Outcome studies in COVID-19 patients with preexisting liver disease and inflammatory bowel disease show predominantly mild transaminase elevations and no increased risk from the use of biological agents in inflammatory bowel disease patients. High-dose corticosteroids, however, should be avoided. As endoscopic procedures are aerosol-generating, modifications to clinical practice is necessary to minimize the spread of COVID-19. We have reviewed current literature to describe the impact of COVID-19 in gastroenterology and hepatology as well as targets of future research.

Calprotectin and SARS-CoV-2: A Brief-Report of the Current Literature

In late December 2019, a novel coronavirus (lately referred to as SARS-CoV-2) spread in the city of Wuhan, China, causing an outbreak of unusual viral pneumonia. In many people, the disease is mild and self-limiting, but in a considerable number of patients, the disease may present more severe or even fatal. Therefore, determining which patients are at higher risk of developing a more severe disease is critical. Some studies have been focused on serum and fecal calprotectin to evaluate COVID-19 disease progression and possible complications. Some assumptions can be made: (1) serum calprotectin may efficiently predict the prognosis of COVID-19 patients; (2) fecal calprotectin may appear high in COVID-19 patients due to the double hit mechanism to the intestine (inflammatory and ischemic); (3) a relationship between the complement system and neutrophil activation contributes to the procoagulant status seen in COVID-19 patients; (4) some patients may develop severe gastro-intestinal complications and fecal calprotectin can be used to monitor intestinal disease activity levels.

Role of Laboratory Medicine in SARS-CoV-2 Diagnostics. Lessons Learned from a Pandemic

Since the 2019 novel coronavirus outbreak began in Wuhan, China, diagnostic methods in the field of molecular biology have been developing faster than ever under the vigilant eye of world's research community. Unfortunately, the medical community was not prepared for testing such large volumes or ranges of biological materials, whether blood samples for antibody immunological testing, or salivary/swab samples for real-time PCR. For this reason, many medical diagnostic laboratories have made the switch to working in the field of molecular biology, and research undertaken to speed up the flow of samples through laboratory. The aim of this narrative review is to evaluate the current literature on laboratory techniques for the diagnosis of SARS-CoV-2 infection available on pubmed.gov, Google Scholar, and according to the writers' knowledge and experience of the laboratory medicine. It assesses the available information in the field of molecular biology by comparing real-time PCR, LAMP technique, RNA sequencing, and immunological diagnostics, and examines the newest techniques along with their limitations for use in SARS-CoV-2 diagnostics.

High fecal calprotectin levels are associated with SARS-CoV-2 intestinal shedding in COVID-19 patients: A proof-of-concept study

BACKGROUND

One third of coronavirus disease 2019 (COVID-19) patients have gastrointestinal symptoms. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA has been detected in stool samples of approximately 50% of COVID-19 individuals. Fecal calprotectin is a marker of gastrointestinal inflammation in the general population.

AIM

To investigate if fecal calprotectin correlates with SARS-CoV-2 intestinal shedding in COVID-19 patients with pneumonia.

METHODS

Patients with SARS-CoV-2 pneumonia admitted to the Infectious Disease Unit (University Hospital of Trieste, Italy) from September to November 2020 were consecutively enrolled in the study. Fecal samples were collected and analyzed for quantification of fecal calprotectin (normal value < 50 mg/kg) and SARS-CoV-2 RNA presence by polymerase chain reaction (PCR). Inter-group differences were determined between patients with and without diarrhea and patients with and without detection of fecal SARS-CoV-2.

RESULTS

We enrolled 51 adults (40 males) with SARS-CoV-2 pneumonia. Ten patients (20%) presented with diarrhea. Real-time-PCR of SARS-CoV-2 in stools was positive in 39 patients (76%), in all patients with diarrhea (100%) and in more than two thirds (29/41, 71%) of patients without diarrhea. Obesity was one of the most common comorbidities (13 patients, 25%); all obese patients (100%) (P = 0.021) tested positive for fecal SARS-CoV-2. Median fecal calprotectin levels were 60 mg/kg [interquartile range (IQR) 21; 108]; higher fecal calprotectin levels were found in the group with SARS-CoV-2 in stools (74 mg/kg, IQR 29; 132.5) compared to the group without SARS-CoV-2 (39 mg/kg, IQR 14; 71) (P < 0.001).

CONCLUSION

High fecal calprotectin levels among COVID-19 patients correlate with SARS-CoV-2 detection in stools supporting the hypothesis that this virus can lead to bowel inflammation and potentially to the 'leaky gut' syndrome.

Endothelial Dysfunction and SARS-CoV-2 Infection: Association and Therapeutic Strategies

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), has been recently considered a systemic disorder leading to the procoagulant state. Preliminary studies have shown that SARS-CoV-2 can infect endothelial cells, and extensive evidence of inflammation and endothelial dysfunction has been found in advanced COVID-19. Endothelial cells play a critical role in many physiological processes, such as controlling blood fluidity, leukocyte activation, adhesion, platelet adhesion and aggregation, and transmigration. Therefore, it is reasonable to think that endothelial dysfunction leads to vascular dysfunction, immune thrombosis, and inflammation associated with COVID-19. This article summarizes the association of endothelial dysfunction and SARS-CoV-2 infection and its therapeutic strategies.

Risk Score for Predicting In-Hospital Mortality in COVID-19 (RIM Score)

Infection by SARS-CoV2 has devastating consequences on health care systems. It is a global health priority to identify patients at risk of fatal outcomes. 1955 patients admitted to HM-Hospitales from 1 March to 10 June 2020 due to COVID-19, were were divided into two groups, 1310 belonged to the training cohort and 645 to validation cohort. Four different models were generated to predict in-hospital mortality. Following variables were included: age, sex, oxygen saturation, level of C-reactive-protein, neutrophil-to-platelet-ratio (NPR), neutrophil-to-lymphocyte-ratio (NLR) and the rate of changes of both hemogram ratios (VNLR and VNPR) during the first week after admission. The accuracy of the models in predicting in-hospital mortality were evaluated using the area under the receiver-operator-characteristic curve (AUC). AUC for models including NLR and NPR performed similarly in both cohorts: NLR 0.873 (95% CI: 0.849–0.898), NPR 0.875 (95% CI: 0.851–0.899) in training cohort and NLR 0.856 (95% CI: 0.818–0.895), NPR 0.863 (95% CI: 0.826–0.901) in validation cohort. AUC was 0.885 (95% CI: 0.885–0.919) for VNLR and 0.891 (95% CI: 0.861–0.922) for VNPR in the validation cohort. According to our results, models are useful in predicting in-hospital mortality risk due to COVID-19. The RIM Score proposed is a simple, widely available tool that can help identify patients at risk of fatal outcomes.

Gastroenterology Procedures Generate Aerosols: An Air Quality Turnover Solution to Mitigate COVID-19's Propagation Risk

The growing fear of virus transmission during the 2019 coronavirus disease (COVID-19) pandemic has called for many scientists to look into the various vehicles of infection, including the potential to travel through aerosols. Few have looked into the issue that gastrointestinal (GI) procedures may produce an abundance of aerosols. The current process of risk management for clinics is to follow a clinic-specific HVAC formula, which is typically calculated once a year and assumes perfect mixing of the air within the space, to determine how many minutes each procedural room refreshes 99% of its air between procedures when doors are closed. This formula is not designed to fit the complex dynamic of small airborne particle transport and deposition that can potentially carry the virus in clinical conditions. It results in reduced procedure throughput as well as an excess of idle time in clinics that process a large number of short procedures such as outpatient GI centers. We present and tested a new cyber-physical system that continuously monitors airborne particle counts in procedural rooms and also at the same time automatically monitors the procedural rooms' state and flexible endoscope status without interfering with the clinic's workflow. We use our data gathered from over 1500 GI cases in one clinical suite to understand the correlation between air quality and standard procedure types as well as identify the risks involved with any HVAC system in a clinical suite environment. Thanks to this system, we demonstrate that standard GI procedures generate large quantities of aerosols, which can potentially promote viral airborne transmission among patients and healthcare staff. We provide a solution for the clinic to improve procedure turnover times and throughput, as well as to mitigate the risk of airborne transmission of the virus.

You Talking to Me? Says the Enteric Nervous System (ENS) to the Microbe. How Intestinal Microbes Interact with the ENS

Mammalian organisms form intimate interfaces with commensal and pathogenic gut microorganisms. Increasing evidence suggests a close interaction between gut microorganisms and the enteric nervous system (ENS), as the first interface to the central nervous system. Each microorganism can exert a different effect on the ENS, including phenotypical neuronal changes or the induction of chemical transmitters that interact with ENS neurons. Some pathogenic bacteria take advantage of the ENS to create a more suitable environment for their growth or to promote the effects of their toxins. In addition, some commensal bacteria can affect the central nervous system (CNS) by locally interacting with the ENS. From the current knowledge emerges an interesting field that may shape future concepts on the pathogen-host synergic interaction. The aim of this narrative review is to report the current findings regarding the inter-relationships between bacteria, viruses, and parasites and the ENS.

Spontaneous Rectal Perforation in a Patient with SARS-CoV-2 Infection

Coronavirus disease 2019 (COVID-19) is mostly perceived as a respiratory disease. However, there is increasing evidence of patients showing gastrointestinal symptoms, with increasing rates of presentation according to the severity of the disease. In a few cases, the abdominal involvement of COVID-19 resulted in spontaneous bowel perforation. Here, we present in detail the first case of rectal perforation in a patient with COVID-19.