The Usefulness of Fecal Calprotectin in the era of the COVID-19 Pandemic

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.

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.

Circulating Calprotectin as a Biomarker of COVID-19 Severity

INTRODUCTION

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although demographic and clinical parameters such as sex, age, comorbidities, genetic background and various biomarkers have been identified as risk factors, there is an unmet need to predict the risk and onset of severe inflammatory disease leading to poor clinical outcomes. In addition, very few mechanistic biomarkers are available to inform targeted treatment of severe (auto)-inflammatory conditions associated with COVID-19. Calprotectin, also known as S100A8/S100A9, MRP8/14 (Myeloid-Related Protein) or L1, is a heterodimer involved in neutrophil-related inflammatory processes. In COVID-19 patients, calprotectin levels were reported to be associated with poor clinical outcomes such as significantly reduced survival time, especially in patients with severe pulmonary disease.

AREAS COVERED

Pubmed was searched using the following keywords: Calprotectin + COVID19, S100A8/A9 + COVID19, S100A8 + COVID-19, S100A9 + COVID-19, MRP8/14 + COVID19; L1 + COVID-19 between May 2020 and 8 March 2021. The results summarized in this review provide supporting evidence and propose future directions that define calprotectin as an important biomarker in COVID-19.

EXPERT OPINION

Calprotectin represents a promising serological biomarker for the risk assessment of COVID-19 patients.

Calprotectin, an Emerging Biomarker of Interest in COVID-19: A Systematic Review and Meta-Analysis

COVID-19 has been shown to present with varied clinical course, necessitating a need for more specific diagnostic tools that could identify severe cases and predict outcomes during COVID-19 infection. Recent evidence has shown an expanded potential role for calprotectin, both as a diagnostic tool and also as a tool in stratifying COVID-19 patients in terms of severity. Therefore, this systematic review and meta-analysis aims to evaluate the levels of calprotectin in severe and non-severe COVID-19 and also identify the implication of raised calprotectin levels. MEDLINE, EMBASE, The Cochrane Library, Web of science and MedRxiv were searched. Meta-analysis was done to compare the serum/fecal levels of calprotectin between severe and non-severe COVID-19 infections. A total of ten studies included in the review (eight had quantitative data while two were qualitative). A pooled analysis of the eight studies from 613 patients who were RT-PCR positive for COVID-19 (average age = 55 years; 52% males) showed an overall estimate as 1.34 (95%CI: 0.77, 1.91). In conclusion, calprotectin levels have been demonstrated to be significantly elevated in COVID-19 patients who develop the severe form of the disease, and it also has prognostic importance.

Calprotectin in Lung Diseases

Calprotectin (CLP) is a heterodimer formed by two S-100 calcium-binding cytosolic proteins, S100A8 and S100A9. It is a multifunctional protein expressed mainly by neutrophils and released extracellularly by activated or damaged cells mediating a broad range of physiological and pathological responses. It has been more than 20 years since the implication of S100A8/A9 in the inflammatory process was shown; however, the evaluation of its role in the pathogenesis of respiratory diseases or its usefulness as a biomarker for the appropriate diagnosis and prognosis of lung diseases have only gained attention in recent years. This review aimed to provide current knowledge regarding the potential role of CLP in the pathophysiology of lung diseases and describe how this knowledge is, up until now, translated into daily clinical practice. CLP is involved in numerous cellular processes in lung health and disease. In addition to its anti-microbial functions, CLP also serves as a molecule with pro- and anti-tumor properties related to cell survival and growth, angiogenesis, DNA damage response, and the remodeling of the extracellular matrix. The findings of this review potentially introduce CLP in daily clinical practice within the spectrum of respiratory diseases.

Implications of COVID-19 for inflammatory bowel disease: Opportunities and challenges amidst the pandemic

Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic various measures have been taken to mitigate the effects of the global health crisis in this unprecedented time. According to the World Health Organization, more than 5 million people have been infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and with more than 300000 deaths attributed to COVID-19 worldwide. There is emerging evidence that SARS-CoV-2 utilizes angiotensin-converting enzyme 2 receptors to enter human cells which are found in abundance in the alveoli and intestines. In addition, the infection is noted to be more severe in patients with co-morbid conditions, those who are malnourished, immunosuppressed and immunocompromised. Inflammatory bowel disease (IBD) which includes ulcerative colitis and Crohn’s disease is chronic remitting and relapsing disorders with intestinal and extraintestinal manifestation. IBD patients are often malnourished and on immunosuppressive medications and there is a hypothetical concern that IBD patients are at substantial risk of COVID-19 infection. The management of IBD patients is often complex and poses unique challenges for gastroenterologists during the pandemic. The purpose of this review article is to summarize the growing level of evidence and understanding of the management of IBD during the COVID-19 pandemic, in the light of international and national gastroenterology society guidelines. We performed a thorough literature search on IBD, SARS-CoV-2 and COVID-19 on PubMed, EMBASE, OVID Medline and Google Scholar and pertaining literature was critically examined and summarized. Per national and international society guidelines and recommendations, IBD is not a risk factor for SARS-CoV-2 infection. IBD patients should continue with their medications and they should follow universal precautions i.e. masks, hand and respiratory hygiene and avoidance of health care facilities and public toilets as general population. Among IBD patients older age, having active disease, and co-morbid conditions are risk factors for a severe SARS-CoV-2 infection. Furthermore, elective endoscopic and surgical procedures can be delayed or deferred until discussing the risks and benefits with patients.

Letter: intestinal inflammation, COVID-19 and gastrointestinal ACE2-exploring RAS inhibitors. Authors' reply

LINKED CONTENT This article is linked to Taxonera et al an Garg et al papers. To view these articles, visit https://doi.org/10.1111/apt.15804 and https://doi.org/10.1111/apt.15814.