Altered gut microbiota in the early stage of acute pancreatitis were related to the occurrence of acute respiratory distress syndrome

Exploring the Role of Gut Microbiota and Probiotics in Acute Pancreatitis: A Comprehensive Review

Acute pancreatitis (AP) is a common and potentially severe gastrointestinal condition characterized by acute inflammation of the pancreas. The pathophysiology of AP is multifactorial and intricate, involving a cascade of events that lead to pancreatic injury and systemic inflammation. The progression of AP is influenced by many factors, including genetic predispositions, environmental triggers, and immune dysregulation. Recent studies showed a critical involvement of the gut microbiota in shaping the immune response and modulating inflammatory processes during AP. This review aims to provide a comprehensive overview of the emerging role of gut microbiota and probiotics in AP. We analyzed the implication of gut microbiota in pathogenesis of AP and the modification during an acute attack. The primary goals of microbiome-based therapies, which include probiotics, prebiotics, antibiotics, fecal microbiota transplantation, and enteral nutrition, are to alter the composition of the gut microbial community and the amount of metabolites derived from the microbiota. By resetting the entire flora or supplementing it with certain beneficial organisms and their byproducts, these therapeutic approaches aim to eradicate harmful microorganisms, reducing inflammation and avoiding bacterial translocation and the potential microbiota-based therapeutic target for AP from nutrition to pre- and probiotic supplementation to fecal transplantation.

Altered Gut Microbiota Contributes to Acute-Respiratory-Distress-Syndrome-Related Depression through Microglial Neuroinflammation

Acute respiratory distress syndrome (ARDS) survivors often suffer from long-term psychiatric disorders such as depression, but the underlying mechanisms remain unclear. Here, we found marked alterations in the composition of gut microbiota in both ARDS patients and mouse models. We investigated the role of one of the dramatically changed bacteria-Akkermansia muciniphila (AKK), whose abundance was negatively correlated with depression phenotypes in both ARDS patients and ARDS mouse models. Specifically, while fecal transplantation from ARDS patients into naive mice led to depressive-like behaviors, microglial activation, and intestinal barrier destruction, colonization of AKK or oral administration of its metabolite-propionic acid-alleviated these deficits in ARDS mice. Mechanistically, AKK and propionic acid decreased microglial activation and neuronal inflammation through inhibiting the Toll-like receptor 4/nuclear factor κB signaling pathway. Together, these results reveal a microbiota-dependent mechanism for ARDS-related depression and provide insight for developing a novel preventative strategy for ARDS-related psychiatric symptoms.

Characterization and comparison of gut microbiota in patients with acute pancreatitis by metagenomics and culturomics

Acute pancreatitis (AP) is a common gastrointestinal disorder with a high mortality rate. This study sought to identify the microbial community structure in patients with AP using metagenomics and culturomics. Compared to healthy controls, patients with AP exhibited a significant decrease in alpha diversity; a higher abundance of unclassified Enterococcus species (sp), Enterococcus faecium, and Enterococcus faecalis; and a lower abundance of Eubacterium rectale. A total of 336 isolates from 25 genera and 44 species were obtained by sample cultivation. The dominant species identified in patients with AP were Enterococcus faecium and Klebsiella grimontii, whereas those in the healthy controls were Enterococcus faecium, Escherichia coli, and Bacteroides faecis. Our research has contributed to the expanded understanding of the genome, diversity, and function of the intestinal microbiota in patients with AP and provided some reference for selecting culture medium and sample processing methods.

Acute respiratory distress syndrome (ARDS): from mechanistic insights to therapeutic strategies

Acute respiratory distress syndrome (ARDS) is a clinical syndrome of acute hypoxic respiratory failure caused by diffuse lung inflammation and edema. ARDS can be precipitated by intrapulmonary factors or extrapulmonary factors, which can lead to severe hypoxemia. Patients suffering from ARDS have high mortality rates, including a 28-day mortality rate of 34.8% and an overall in-hospital mortality rate of 40.0%. The pathophysiology of ARDS is complex and involves the activation and dysregulation of multiple overlapping and interacting pathways of systemic inflammation and coagulation, including the respiratory system, circulatory system, and immune system. In general, the treatment of inflammatory injuries is a coordinated process that involves the downregulation of proinflammatory pathways and the upregulation of anti-inflammatory pathways. Given the complexity of the underlying disease, treatment needs to be tailored to the problem. Hence, we discuss the pathogenesis and treatment methods of affected organs, including 2019 coronavirus disease (COVID-19)-related pneumonia, drowning, trauma, blood transfusion, severe acute pancreatitis, and sepsis. This review is intended to provide a new perspective concerning ARDS and offer novel insight into future therapeutic interventions.

Updated review of research on the role of the gut microbiota and microbiota-derived metabolites in acute pancreatitis progression and inflammation-targeted therapy

Acute pancreatitis (AP) is characterized by autodigestion of the pancreas, and some patients may rapidly progress to systemic inflammation, pancreatic necrosis, and multi-organ failure. Numerous studies have detailed the bidirectional communication networks between the pancreas and the intestinal microbiota, as well as its metabolites. Such crosstalk affects the progression of AP and recovery through intestinal barrier disruption. Furthermore, advances in experimental research and clinical studies have indicated that gut microorganisms exhibit distinct alterations in response to different levels of severity and etiologies of AP. This information has greatly expanded our knowledge of the role of the gut microflora and microbial metabolites in the pathology of disease and has reinforced the basis of therapeutic approaches that target candidate intestinal microbiota. In this review, we aim to provide an overview of the composition and diversity of the gut microbial community, to highlight the candidate bacteria and microbiota-derived metabolites responsible for AP, and to elucidate their interactions with and regulation of immune-relevant receptors in intestinal epithelial cells (IECs) in the host. Future research should focus on identifying and characterizing AP-associated bacterial strains, elucidating their distinct pathogenic mechanisms across different etiologies and stages of AP, and leveraging these insights to develop preventive and therapeutic strategies.

Profile of intestinal fungal microbiota in acute pancreatitis patients and healthy individuals

OBJECTIVE

The gut is involved in the development of acute pancreatitis (AP). Increased focus is being given to the role of gut microbiota in the pathogenesis of AP. Nevertheless, there is currently no available evidence regarding the composition of fungal microorganisms in the intestines of patients with AP.

METHODS

In this study, we sequenced ITS rRNA gene amplicons and examined the intestinal fungal microbiota in feces from 11 AP patients (the test group) and 15 healthy people (the control group). Additionally, we examined the relationship between fungus and clinical and biochemical markers.

RESULTS

Results showed a decline in alpha diversity in AP patients. The overall fungal microbiota in the test group was significantly different from that of the control group (P < 0.05). In both groups, the fecal fungal microbiota was dominated by Ascomycota and Basidiomycota phyla. At the genus level, the abundance of Candida was significantly higher in the test group and the abundances of Penicillium, Auricularia, unclassified Eurotiomycetes, Epicoccum and Vishniacozyma were significantly lower. Furthermore, AP patients had a significant decrease in the GMHI score and a significant increase in the MDI index. The co-abundance networks of gut fungus in AP patients showed more interactions and mostly positive correlations than in the control group. There was a strong positive link between Aspergillus and WBC counts, while There was a strong link between unclassified Rozellomycota and IL-6.

CONCLUSION

Our study provides the first empirical evidence that AP patients have different fecal fungal microbiota, which raises the possibility that mycobiota contribute to the etiology and progression of AP.

Alterations in microbiome associated with acute pancreatitis

PURPOSE OF REVIEW

This review evaluates the current knowledge of gut microbiome alterations in acute pancreatitis, including those that can increase acute pancreatitis risk or worsen disease severity, and the mechanisms of gut microbiome driven injury in acute pancreatitis.

RECENT FINDINGS

Recent observational studies in humans showed the association of gut microbiome changes (decreased gut microbiome diversity, alterations in relative abundances of certain species, and association of unique species with functional pathways) with acute pancreatitis risk and severity. Furthermore, in-vivo studies highlighted the role of gut microbiome in the development and severity of acute pancreatitis using FMT models. The gut barrier integrity, immune cell homeostasis, and microbial metabolites appear to play key roles in acute pancreatitis risk and severity.

SUMMARY

Large human cohort studies that assess gut microbiome profile, its metabolites and impact on acute pancreatitis risk and severity will be crucial for development of innovative prediction, prevention and treatment strategies.

Exploring the gut microbiota's crucial role in acute pancreatitis and the novel therapeutic potential of derived extracellular vesicles

During acute pancreatitis, intestinal permeability increases due to intestinal motility dysfunction, microcirculatory disorders, and ischemia-reperfusion injury, and disturbances in the intestinal flora make bacterial translocation easier, which consequently leads to local or systemic complications such as pancreatic and peripancreatic necrotic infections, acute lung injury, systemic inflammatory response syndrome, and multiple organ dysfunction syndrome. Therefore, adjusting intestinal ecosystem balance may be a promising approach to control local and systemic complications of acute pancreatitis. In this paper, we reviewed the causes and manifestations of intestinal flora disorders during acute pancreatitis and their complications, focused on the reduction of acute pancreatitis and its complications by adjusting the intestinal microbial balance, and innovatively proposed the treatment of acute pancreatitis and its complications by gut microbiota-derived extracellular vesicles.

Gut-derived immune cells and the gut-lung axis in ARDS

The gut serves as a vital immunological organ orchestrating immune responses and influencing distant mucosal sites, notably the respiratory mucosa. It is increasingly recognized as a central driver of critical illnesses, with intestinal hyperpermeability facilitating bacterial translocation, systemic inflammation, and organ damage. The "gut-lung" axis emerges as a pivotal pathway, where gut-derived injurious factors trigger acute lung injury (ALI) through the systemic circulation. Direct and indirect effects of gut microbiota significantly impact immune responses. Dysbiosis, particularly intestinal dysbiosis, termed as an imbalance of microbial species and a reduction in microbial diversity within certain bodily microbiomes, influences adaptive immune responses, including differentiating T regulatory cells (Tregs) and T helper 17 (Th17) cells, which are critical in various lung inflammatory conditions. Additionally, gut and bone marrow immune cells impact pulmonary immune activity, underscoring the complex gut-lung interplay. Moreover, lung microbiota alterations are implicated in diverse gut pathologies, affecting local and systemic immune landscapes. Notably, lung dysbiosis can reciprocally influence gut microbiota composition, indicating bidirectional gut-lung communication. In this review, we investigate the pathophysiology of ALI/acute respiratory distress syndrome (ARDS), elucidating the role of immune cells in the gut-lung axis based on recent experimental and clinical research. This exploration aims to enhance understanding of ALI/ARDS pathogenesis and to underscore the significance of gut-lung interactions in respiratory diseases.

Exploring the Microbial Landscape: Gut Dysbiosis and Therapeutic Strategies in Pancreatitis-A Narrative Review

The gut microbiota is emerging as an important contributor to the homeostasis of the human body through its involvement in nutrition and metabolism, protection against pathogens, and the development and modulation of the immune system. It has therefore become an important research topic in recent decades. Although the association between intestinal dysbiosis and numerous digestive pathologies has been thoroughly researched, its involvement in pancreatic diseases constitutes a novelty in the specialized literature. In recent years, growing evidence has pointed to the critical involvement of the pancreas in regulating the intestinal microbiota, as well as the impact of the intestinal microbiota on pancreatic physiology, which implies the existence of a bidirectional connection known as the "gut-pancreas axis". It is theorized that any change at either of these levels triggers a response in the other component, hence leading to the evolution of pancreatitis. However, there are not enough data to determine whether gut dysbiosis is an underlying cause or a result of pancreatitis; therefore, more research is needed in this area. The purpose of this narrative review is to highlight the role of gut dysbiosis in the pathogenesis of acute and chronic pancreatitis, its evolution, and the prospect of employing the microbiota as a therapeutic intervention for pancreatitis.

Gut microbiota predicts severity and reveals novel metabolic signatures in acute pancreatitis

OBJECTIVE

Early disease prediction is challenging in acute pancreatitis (AP). Here, we prospectively investigate whether the microbiome predicts severity of AP (Pancreatitis-Microbiome As Predictor of Severity; P-MAPS) early at hospital admission.

DESIGN

Buccal and rectal microbial swabs were collected from 424 patients with AP within 72 hours of hospital admission in 15 European centres. All samples were sequenced by full-length 16S rRNA and metagenomic sequencing using Oxford Nanopore Technologies. Primary endpoint was the association of the orointestinal microbiome with the revised Atlanta classification (RAC). Secondary endpoints were mortality, length of hospital stay and severity (organ failure >48 hours and/or occurrence of pancreatic collections requiring intervention) as post hoc analysis. Multivariate analysis was conducted from normalised microbial and corresponding clinical data to build classifiers for predicting severity. For functional profiling, gene set enrichment analysis (GSEA) was performed and normalised enrichment scores calculated.

RESULTS

After data processing, 411 buccal and 391 rectal samples were analysed. The intestinal microbiome significantly differed for the RAC (Bray-Curtis, p value=0.009), mortality (Bray-Curtis, p value 0.006), length of hospital stay (Bray-Curtis, p=0.009) and severity (Bray-Curtis, p value=0.008). A classifier for severity with 16 different species and systemic inflammatory response syndrome achieved an area under the receiving operating characteristic (AUROC) of 85%, a positive predictive value of 67% and a negative predictive value of 94% outperforming established severity scores. GSEA revealed functional pathway units suggesting elevated short-chain fatty acid (SCFA) production in severe AP.

CONCLUSIONS

The orointestinal microbiome predicts clinical hallmark features of AP, and SCFAs may be used for future diagnostic and therapeutic concepts.

TRIAL REGISTRATION NUMBER

NCT04777812.

Gut microbiota and its metabolic products in acute respiratory distress syndrome

The prevalence rate of acute respiratory distress syndrome (ARDS) is estimated at approximately 10% in critically ill patients worldwide, with the mortality rate ranging from 17% to 39%. Currently, ARDS mortality is usually higher in patients with COVID-19, giving another challenge for ARDS treatment. However, the treatment efficacy for ARDS is far from satisfactory. The relationship between the gut microbiota and ARDS has been substantiated by relevant scientific studies. ARDS not only changes the distribution of gut microbiota, but also influences intestinal mucosal barrier through the alteration of gut microbiota. The modulation of gut microbiota can impact the onset and progression of ARDS by triggering dysfunctions in inflammatory response and immune cells, oxidative stress, cell apoptosis, autophagy, pyroptosis, and ferroptosis mechanisms. Meanwhile, ARDS may also influence the distribution of metabolic products of gut microbiota. In this review, we focus on the impact of ARDS on gut microbiota and how the alteration of gut microbiota further influences the immune function, cellular functions and related signaling pathways during ARDS. The roles of gut microbiota-derived metabolites in the development and occurrence of ARDS are also discussed.

Comparison of gut microbiota dysbiosis between pemphigus vulgaris and bullous pemphigoid

OBJECTIVE

Pemphigus vulgaris (PV) and bullous pemphigoid (BP) are two prevalent bullous diseases. Previous studies found that the antibodies of BP could be expressed in the intestinal epithelium and BP was tightly related to inflammatory bowel disease. Therefore, gut microbiota might also play an important role in bullous disease. However, the specific relationship between gut microbiota and bullous diseases remains unknown. Our study aimed to investigate the potential role of gut microbiota in the development and progression of different bullous diseases.

METHODS

We conducted a prospective and observational cohort study at Peking Union Medical College Hospital. Untreated BP and PV patients were recruited, along with healthy controls (HC) who were spouses or caregivers of these patients. Fecal samples were collected, followed by 16S rRNA gene sequencing. Bioinformatics analyses were performed to assess the composition and function of gut microbiota.

RESULTS

A total of 38 HC, 32 BP, and 19 PV patients were enrolled in this study. Compared to HC, BP, and PV exhibited a distinct gut microbiota composition, especially BP. The gut microbiota changes were mainly observed in the phylum Bacteroidetes, Firmicutes, and Proteobacteria. The ratio of Faecalibacterium to Escherichia-Shigella (F/E ratio) had a considerable predictive value (AUC: 0.705) for recognizing BP from PV. The levels of Faecalibacterium and Enterobacter were correlated to the anti-BP 180 and anti-desmoglein 3. Microbial functional prediction revealed elevated activity in pathways related to gut microbiota translocation significantly increased in BP patients, indicating a potential pathogenetic role in BP.

CONCLUSIONS

Our study suggests that the composition of gut microbiota is specific in different bullous diseases and the role of gut microbiota differs. Gut microbiota could help distinguish BP and PV, and might play a role in the pathogenesis of different bullous diseases.

The Role of the Gut Microbiome in the Development of Acute Pancreatitis

With the explosion research on the gut microbiome in the recent years, much insight has been accumulated in comprehending the crosstalk between the gut microbiota community and host health. Acute pancreatitis (AP) is one of the gastrointestinal diseases associated with significant morbidity and subsequent mortality. Studies have elucidated that gut microbiota are engaged in the pathological process of AP. Herein, we summarize the major roles of the gut microbiome in the development of AP. We then portray the association between dysbiosis of the gut microbiota and the severity of AP. Finally, we illustrate the promises and challenges that arise when seeking to incorporate the microbiome in acute pancreatitis treatment.

Role of gut microbes in acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI) is an acute, diffuse inflammatory lung condition triggered by factors of severe infections, trauma, shock, burns, ischemia-reperfusion, and mechanical ventilation. It is primarily characterized by refractory hypoxemia and respiratory distress. The more severe form, acute respiratory distress syndrome (ARDS), can progress to multi-organ failure and has a high mortality rate. Despite extensive research, the exact pathogenesis of ALI and ARDS remains complex and not fully understood. Recent advancements in studying the gut microecology of patients have revealed the critical role that gut microbes play in ALI/ARDS onset and progression. While the exact mechanisms are still under investigation, evidence increasingly points to the influence of gut microbes and their metabolites on ALI/ARDS. This review aims to summarize the role of gut microbes and their metabolites in ALI/ARDS caused by various triggers. Moreover, it explores potential mechanisms and discusses how gut microbe-targeting interventions might offer new clinical strategies for the treatment of ALI/ARDS.

Role of gut microbiota and inflammatory factors in acute respiratory distress syndrome: a Mendelian randomization analysis

Background

Acute respiratory distress syndrome (ARDS) is a serious lung ailment marked by significant inflammation and damage in the alveoli and capillaries of the lungs. Recent research suggests a strong correlation between the onset and advancement of ARDS and an imbalance in the gut microbiota (GM).

Methods

In this investigation, Mendelian randomization (MR) analysis was utilized, drawing on data from publicly accessible genome-wide association studies. The primary focus was on examining the interplay between GM, inflammatory factors (IFs) and ARDS. Instrumental variables were established through genetic modifications of GM and IFs. Various statistical analysis methods including the inverse-variance weighted model, MR-Egger method and Wald ratio test were applied for comprehensive data analysis.

Results

Eight bacterial taxa within the GM demonstrated a potential causal link with development of ARDS. Notably, the phylum Actinobacteria and the genus Intestinibacter exhibited a negative association with the risk of ARDS. However, Erysipelotrichales (id. 2,148), Victivallis (id. 2,256), Ruminococcaceae UCG014 (id. 11,371), Eubacterium ruminantium group (id. 11,340), Erysipelotrichaceae (id. 2,149) and Erysipelotrichia (id. 2,147) demonstrated a positive association with ARDS risk. Additionally, the study identified a potential causal relationship between the inflammatory factors interleukin-16 and C-C motif chemokine 3 with the occurrence of ARDS.

Conclusion

This study strongly suggests that the interaction between gut microbiota (GM) and inflammatory factors (IFs) significantly contributes to the pathogenesis of acute respiratory distress syndrome (ARDS). This underscores their crucial involvement in both the initiation and advancement of this severe lung disorder.

Causal link between gut microbiota and four types of pancreatitis: a genetic association and bidirectional Mendelian randomization study

BACKGROUND

A number of recent observational studies have indicated a correlation between the constitution of gut microbiota and the incidence of pancreatitis. Notwithstanding, observational studies are unreliable for inferring causality because of their susceptibility to confounding, bias, and reverse causality, the causal relationship between specific gut microbiota and pancreatitis is still unclear. Therefore, our study aimed to investigate the causal relationship between gut microbiota and four types of pancreatitis.

METHODS

An investigative undertaking encompassing a genome-wide association study (GWAS) comprising 18,340 participants was undertaken with the aim of discerning genetic instrumental variables that exhibit associations with gut microbiota, The aggregated statistical data pertaining to acute pancreatitis (AP), alcohol-induced AP (AAP), chronic pancreatitis (CP), and alcohol-induced CP (ACP) were acquired from the FinnGen Consortium. The two-sample bidirectional Mendelian randomization (MR) approach was utilized. Utilizing the Inverse-Variance Weighted (IVW) technique as the cornerstone of our primary analysis. The Bonferroni analysis was used to correct for multiple testing, In addition, a number of sensitivity analysis methodologies, comprising the MR-Egger intercept test, the Cochran's Q test, MR polymorphism residual and outlier (MR-PRESSO) test, and the leave-one-out test, were performed to evaluate the robustness of our findings.

RESULTS

A total of 28 intestinal microflora were ascertained to exhibit significant associations with diverse outcomes of pancreatitis. Among them, Class Melainabacteria (OR = 1.801, 95% CI: 1.288-2.519, p = 0.008) has a strong causality with ACP after the Bonferroni-corrected test, in order to assess potential reverse causation effects, we used four types of pancreatitis as the exposure variable and scrutinized its impact on gut microbiota as the outcome variable, this analysis revealed associations between pancreatitis and 30 distinct types of gut microflora. The implementation of Cochran's Q test revealed a lack of substantial heterogeneity among the various single nucleotide polymorphisms (SNP).

CONCLUSION

Our first systematic Mendelian randomization analysis provides evidence that multiple gut microbiota taxa may be causally associated with four types of pancreatitis disease. This discovery may contribute significant biomarkers conducive to the preliminary, non-invasive identification of Pancreatitis. Additionally, it could present viable targets for potential therapeutic interventions in the disease's treatment.

The Role of Short-Chain Fatty Acids in Acute Pancreatitis

Acute pancreatitis (AP) is a digestive emergency and can develop into a systematic illness. The role of the gut in the progression and deterioration of AP has drawn much attention from researchers, and areas of interest include dysbiosis of the intestinal flora, weakened intestinal barrier function, and bacterial and endotoxin translocation. Short-chain fatty acids (SCFAs), as one of the metabolites of gut microbiota, have been proven to be depleted in AP patients. SCFAs help restore gut homeostasis by rebuilding gut flora, stabilizing the intestinal epithelial barrier, and regulating inflammation. SCFAs can also suppress systematic inflammatory responses, improve the injured pancreas, and prevent and protect other organ dysfunctions. Based on multiple beneficial effects, increasing SCFAs is an essential idea of gut protective treatment in AP. Specific strategies include the direct use of butyrate or indirect supplementation through fiber, pre/pro/synbiotics, or fecal microbiota transplantation as a promising adjective therapy to enteral nutrition.