Decreased Gut Microbiome Tryptophan Metabolism and Serotonergic Signaling in Patients With Persistent Mental Health and Gastrointestinal Symptoms After COVID-19

How to understand the overlap of long COVID, chronic fatigue syndrome/myalgic encephalomyelitis, fibromyalgia and irritable bowel syndromes

Long COVID should be limited to patients with multiple, persistent symptoms not related to well-defined organ damage. Once redefined, a focused review of long COVID demonstrates striking similarity to chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), fibromyalgia (FM) and irritable bowel syndrome (IBS). Research in long COVID has revealed similar findings to those noted in CFS/ME and FM, characterized by central nervous system organ dysfunction. Long COVID, like CFS/ME, FM and IBS, is best understood as a bidirectional mind-body, neuroimmune illness.

Unmasking the mental health scars of COVID-19: A longitudinal investigation of children and adolescents in post-lockdown China

The long-term mental health consequences of COVID-19 in children and adolescents remain unclear. We investigated the impact of COVID-19 infection on mental health after China's zero-COVID policy relaxation, focusing on symptom-specific and social-family risk factors for mental health issues in children and adolescents. In a longitudinal study, 8348 youths (aged 10-18) were assessed twice (T1: September to October 2022 and T2: April to May 2023). Mental health changes (Δ=T1-T2) were compared between COVID-19-infected (COVID+, n = 4108) and non-infected (COVID-, n = 4240). After balancing social-family confounding factors at T1 with propensity score-based inverse probability weights, multivariable logistic regression was employed to assess associations between COVID-19 infection and the onset/worsening of mental health symptoms. Multivariable logistic regression was conducted to explore specific acute COVID-19 symptoms and social-family risk factors associated with the onset/worsening of mental health symptoms in COVID + group. Compared to COVID- group, COVID + group exhibited lower overall mental health improvement (Δ). COVID + group was associated with increased risks of depression worsening (OR 1.20, 95 % CI 1.04-1.39), anxiety worsening (OR 1.30, 95 % CI 1.15-1.47), stress worsening (OR 1.23, 95 % CI 1.03-1.46), insomnia worsening (OR 1.21, 95 % CI 1.05-1.39), and emotional symptoms worsening (OR 1.72, 95 % CI 1.27-2.33). Moderate-to-severe difficulty thinking, breathlessness, and gastrointestinal symptoms were specific COVID-19 symptoms associated with worsening of various mental health outcomes. Furthermore, academic difficulties, economic disadvantages, family conflicts, food addiction, and alcohol consumption were identified as social-family risk factors for worsening mental health symptoms in COVID + youths. COVID-19 infection leaves lasting mental health scars in youths, extending beyond the acute phase. Specific symptoms, particularly cognitive dysfunction and respiratory/gastrointestinal distress play a significant role in this vulnerability. Social-family factors further modulate these effects, highlighting the need for comprehensive interventions that address both biological and psychosocial aspects. This study provides valuable insights for tailoring mental health support to youths navigating the consequences of the COVID-19 pandemic.

Effect of gut microbiome on serotonin metabolism: a personalized treatment approach

Several factors including diet, exercise, and medications influence the makeup of the resilient but adaptable gut microbiome. Bacteria in the gut have a significant role in the homeostasis of the neurotransmitter serotonin, also known as 5-hydroxytryptamine, involved in mood and behavior. The goal of the current work is to review the effect of the gut microbiome on serotonin metabolism, and how it can potentially contribute to the development of a personalized treatment approach for depression and anxiety. Bacterial strains provide innovative therapeutic targets that can be used for disorders, such as depression, that involve dysregulation of serotonin. Advances in bacterial genomic sequencing have increased the accessibility and affordability of microbiome testing, which unlocks a new targeted pathway to modulate serotonin metabolism by targeting the gut-brain axis. Microbiome testing can facilitate the recommendation of strain-specific probiotic supplements based on patient-specific microbial profiles. Several studies have shown that supplementation with probiotics containing specific species of bacteria, such as Bifidobacterium and Lactobacillus, can improve symptoms of depression. Further research is needed to improve the process and interpretation of microbiome testing and how to successfully incorporate testing results into guiding clinical decision-making. This targeted approach centered around the gut-brain axis can provide a novel way to personalize therapy for mental health disorders.

Urinary phenotyping of SARS-CoV-2 infection connects clinical diagnostics with metabolomics and uncovers impaired NAD+ pathway and SIRT1 activation

OBJECTIVES

The stratification of individuals suffering from acute and post-acute SARS-CoV-2 infection remains a critical challenge. Notably, biomarkers able to specifically monitor viral progression, providing details about patient clinical status, are still not available. Herein, quantitative metabolomics is progressively recognized as a useful tool to describe the consequences of virus-host interactions considering also clinical metadata.

METHODS

The present study characterized the urinary metabolic profile of 243 infected individuals by quantitative nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography mass spectrometry (LC-MS). Results were compared with a historical cohort of noninfected subjects. Moreover, we assessed the concentration of recently identified antiviral nucleosides and their association with other metabolites and clinical data.

RESULTS

Urinary metabolomics can stratify patients into classes of disease severity, with a discrimination ability comparable to that of clinical biomarkers. Kynurenines showed the highest fold change in clinically-deteriorated patients and higher-risk subjects. Unique metabolite clusters were also generated based on age, sex, and body mass index (BMI). Changes in the concentration of antiviral nucleosides were associated with either other metabolites or clinical variables. Increased kynurenines and reduced trigonelline excretion indicated a disrupted nicotinamide adenine nucleotide (NAD+) and sirtuin 1 (SIRT1) pathway.

CONCLUSIONS

Our results confirm the potential of urinary metabolomics for noninvasive diagnostic/prognostic screening and show that the antiviral nucleosides could represent novel biomarkers linking viral load, immune response, and metabolism. Moreover, we established for the first time a casual link between kynurenine accumulation and deranged NAD+/SIRT1, offering a novel mechanism through which SARS-CoV-2 manipulates host physiology.

Global landscape of COVID-19 research: a visualization analysis of randomized clinical trials

The emergence of COVID-19 in 2019 has resulted in a significant global health crisis. Consequently, extensive research was published to understand and mitigate the disease. In particular, randomized controlled trials (RCTs) have been considered the benchmark for assessing the efficacy and safety of interventions. Hence, the present study strives to present a comprehensive overview of the global research landscape pertaining to RCTs and COVID-19. A bibliometric analysis was performed using the Scopus database. The search parameters included articles published from 2020 to 2022 using keywords specifically related to COVID-19 and RCTs. The data were analyzed using various bibliometric indicators. The volume of publications, contributions of countries and institutions, funding agencies, active journals, citation analysis, co-occurrence analysis, and future research direction analysis were specifically analyzed. A total of 223,480 research articles concerning COVID-19 were published, with 3,727 of them related to RCTs and COVID-19. The ten most productive countries collectively produced 75.8% of the documents, with the United States leading the way by contributing 31.77%, followed by the UK with 14.03% (n = 523), China with 12.96% (n = 483) and Canada with 7.16% (n = 267). Trials (n = 173, 4.64%), BMJ Open (n = 81, 2.17%), PLOS One (n = 73, 1.96%) and JAMA Network Open (n = 53, 1.42%) were the most active journals in publishing articles related to COVID-19 RCTs. The co-occurrence analysis identified four clusters of research areas: the safety and effectiveness of COVID-19 vaccines, mental health strategies to cope with the impact of the pandemic, the use of monoclonal antibodies to treat patients with COVID-19, and systematic reviews and meta-analyses of COVID-19 research. This paper offers a detailed examination of the global research environment pertaining to RCTs and their use in the context of the COVID-19 pandemic. The comprehensive body of research findings was found to have been generated by the collaborative efforts of multiple countries, institutions, and funding organizations. The predominant research areas encompassed COVID-19 vaccines, strategies for mental health, monoclonal antibodies, and systematic reviews. This information has the potential to aid researchers, policymakers, and funders in discerning areas of weakness and establishing areas of priority.

The long-term health outcomes, pathophysiological mechanisms and multidisciplinary management of long COVID

There have been hundreds of millions of cases of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With the growing population of recovered patients, it is crucial to understand the long-term consequences of the disease and management strategies. Although COVID-19 was initially considered an acute respiratory illness, recent evidence suggests that manifestations including but not limited to those of the cardiovascular, respiratory, neuropsychiatric, gastrointestinal, reproductive, and musculoskeletal systems may persist long after the acute phase. These persistent manifestations, also referred to as long COVID, could impact all patients with COVID-19 across the full spectrum of illness severity. Herein, we comprehensively review the current literature on long COVID, highlighting its epidemiological understanding, the impact of vaccinations, organ-specific sequelae, pathophysiological mechanisms, and multidisciplinary management strategies. In addition, the impact of psychological and psychosomatic factors is also underscored. Despite these crucial findings on long COVID, the current diagnostic and therapeutic strategies based on previous experience and pilot studies remain inadequate, and well-designed clinical trials should be prioritized to validate existing hypotheses. Thus, we propose the primary challenges concerning biological knowledge gaps and efficient remedies as well as discuss the corresponding recommendations.

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.

A novel hACE2 knock-in mouse model recapitulates pulmonary and intestinal SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission is responsible for the coronavirus disease 2019 (COVID-19) pandemic. SARS-CoV-2 uses the angiotensin-converting enzyme 2 (ACE2) receptor to enter the host, and the gastrointestinal tract is a potential infection site as this receptor is expressed on it. Multiple studies have indicated that an increasing number of COVID-19 patients presented with gastrointestinal symptoms that are highly associated with disease severity. Moreover, emerging evidence has demonstrated that alterations in the gut immune microenvironment induced by intestinal SARS-CoV-2 infection can regulate respiratory symptoms. Therefore, targeting the intestines may be a candidate therapeutic strategy in patients with COVID-19; however, no mouse model can serve as an appropriate infection model for the development of fatal pneumonia while mimicking intestinal infection. In this study, a novel human ACE2 knock-in (KI) mouse model (or hACE2-KI) was systemically compared with the popular K18-hACE2 mice; it showed differences in the distribution of lung and intestinal infections and pathophysiological characteristics. These newly generated hACE2-KI mice were susceptible to intranasal infection with SARS-CoV-2, and not only developed mild to severe lung injury, but also acquired intestinal infection. Consequently, this model can be a useful tool for studying intestinal SARS-CoV-2 infection and developing effective therapeutic strategies.

Factors associated with negative conversion of viral RNA in hospitalized children infected with SARS-CoV-2 Omicron variant in Shanghai, China: a retrospective analysis

OBJECTIVES

This study aimed to identify the related risk factors and potential predictors of SARS-CoV-2 RNA negative conversion by describing the dynamics of viral shedding in infected children admitted to two hospitals from Shanghai during the Omicron variant outbreak.

METHODS

This retrospective cohort included laboratory-confirmed cases of SARS-CoV-2 infection from Shanghai between March 28 and May 31, 2022. Clinical characteristics, personal vaccination, and household vaccination rates were collected through electronic health records and telephone interviews.

RESULTS

A total of 603 paediatric patients confirmed to have COVID-19 were included in this study. Both univariate and multivariate analyses were performed to filter independent factors for the duration to viral RNA negative conversion. Data on the redetection of SARS-CoV-2 in the patients after they showed negative results on the RT‒PCR test (intermittent negative status) were also analysed. The median duration of virus shedding was 12 (interquartile range, IQR: 10-14) days. The severity of clinical outcome, personal vaccination-2doses, household vaccination rates, and abnormal defecation were factors indecently affecting negative conversion of SARS-CoV-2 RNA, suggesting that patients who had abnormal defecation or with more severe conditions would have delayed virological clearance, while patients who previously had 2 doses of vaccination or had higher household vaccination rates would have accelerated virological clearance. Loss of appetite (odds ratio (OR): 5.343; 95% CI: 3.307-8.632) and abnormal defecation (OR: 2.840; 95% CI: 1.736-4.645) were significantly associated with intermittent negative status.

CONCLUSION

These findings could provide clues for the early identification of paediatric patients with prolonged viral shedding and could enrich the evidence for the development of prevention and control strategies, especially vaccination policies for children and adolescents.

Folgen nach SARS-CoV-2-Infektion einschließlich Post-COVID-Syndrom

Eine Infektion mit dem „severe acute respiratory syndrome coronavirus type 2“ (SARS-CoV-2) kann vielfältige gastroenterologische Symptome hervorrufen. Ein relevanter Anteil an Patient:innen klagt über Symptome einer Gastroenteritis; die Zahl der Betroffenen hat mit der Verbreitung der Omikron-Varianten zugenommen. Ebenso finden sich bei Infizierten Zeichen einer Leberbeteiligung, die sich durch erhöhte Leberfermente bis hin zu einer akuten Dekompensation ausdrückt. Bei Patient:innen mit vorbestehenden Lebererkrankungen kann sich diese in der akuten Phase der Infektion verschlechtern und z. B. in ein akut-auf-chronisches Leberversagen übergehen. Hiervon abzugrenzen sind langfristige Folgen der SARS-CoV-2-Infektion. Diese können sich entweder als direkte infektions- oder therapieassoziierte Folgen, wie der Entwicklung einer sekundär-sklerosierenden Cholangitis nach Intensivtherapie, äußern oder als Symptome im Rahmen eines Post-coronavirus-disease(COVID)-Syndroms. Dessen Pathophysiologie ist weiterhin ungeklärt; hier wird ein Einfluss des intestinalen Mikrobioms diskutiert. In dieser Übersichtsarbeit werden die akuten Symptome und chronischen Folgen einer SARS-CoV-2-Infektion, mit denen man im Alltag zunehmend konfrontiert wird, dargestellt.

Post-COVID-19 Syndrome Comprehensive Assessment: From Clinical Diagnosis to Imaging and Biochemical-Guided Diagnosis and Management

The COVID-19 outbreak was first reported in 2019, causing massive morbidity and mortality. The majority of the COVID-19 patients survived and developed Post-COVID-19 Syndrome (PC19S) of varying severity. Currently, the diagnosis of PC19S is achieved through history and symptomatology that cannot be explained by an alternative diagnosis. However, the heavy reliance on subjective reporting is prone to reporting errors. Besides, there is no unified diagnostic assessment tool to classify the clinical severity of patients. This leads to significant difficulties when managing patients in terms of public resource utilization, clinical progression monitorization and rehabilitation plan formulation. This narrative review aims to review current evidence of diagnosis based on triple assessment: clinical symptomatology, biochemical analysis and imaging evidence. Further assessment tools can be developed based on triple assessment to monitor patient's clinical progression, prognosis and intervals of monitoring. It also highlights the high-risk features of patients for closer and earlier monitoring. Rehabilitation programs and related clinical trials are evaluated; however, most of them focus on cardiorespiratory fitness and psychiatric presentations such as anxiety and depression. Further research is required to establish an objective and comprehensive assessment tool to facilitate clinical management and rehabilitation plans.

Association between Gut Microbiota and SARS-CoV-2 Infection and Vaccine Immunogenicity

Gut microbiota is increasingly recognized to play a pivotal role in various human physiological functions and diseases. Amidst the COVID-19 pandemic, research has suggested that dysbiosis of the gut microbiota is also involved in the development and severity of COVID-19 symptoms by regulating SARS-CoV-2 entry and modulating inflammation. Previous studies have also suggested that gut microbiota and their metabolites could have immunomodulatory effects on vaccine immunogenicity, including influenza vaccines and oral rotavirus vaccines. In light of these observations, it is possible that gut microbiota plays a role in influencing the immune responses to COVID-19 vaccinations via similar mechanisms including effects of lipopolysaccharides, flagellin, peptidoglycan, and short-chain fatty acids. In this review, we give an overview of the current understanding on the role of the gut microbiota in COVID-19 manifestations and vaccine immunogenicity. We then discuss the limitations of currently published studies on the associations between gut microbiota and COVID-19 vaccine outcomes. Future research directions shall be focused on the development of microbiota-based interventions on improving immune response to SARS-CoV-2 infection and vaccinations.