Clinical Parameters and Gut Microbiome Changes Before and After Surgery in Thoracic Aortic Dissection in Patients with Gastrointestinal Complications

Characterization of "microbiome-metabolome-immunity" in depressed rats with divergent responses to Paroxetine

OBJECTIVES

Selective serotonin reuptake inhibitors (SSRIs) are the first-line anti-depressants. Unfortunately, about 30 % depressed patients do not effectively respond to SSRIs. It is still unclear that the gastrointestinal characteristics of responders and non-responders, and the differences.

METHODS

Herein, we characterized gut microbiome and metabolome of depressed rats with differential responses to Paroxetine (PX) by 16S rRNA sequencing and 1H NMR-based metabolomics, respectively. On top of this, we constructed both inter- and inner-layer networks, intuitively showing the correlations among behavioral indicators, immune factors, intestinal bacteria, and differential metabolites.

RESULTS

Consequently, we found that depressed rats differently responded to PX, which could be divided into PX responsive (PX-R) and non-responsive (PX-N) groups. Firstly, the depressive behaviors of PX-R rats and PX-N rats significantly differed. Meanwhile, inflammatory balance was also characterized for depressed rats with different responses to PX. Overall, PX-R rats and PX-N rats exhibited differential gut microbiome and metabolome, including intestinal structures, intestinal functions, metabolic profiles, metabolites, and metabolic pathways.

LIMITATIONS

Metabolites that identified by metabolomics based on 1H NMR are not comprehensive enough.

CONCLUSIONS

Taken together, our study demonstrated that gut microbiome and metabolome, as well as related functions, are of significance in differential responses of depressed rats to PX, which might be novel insights in uncovering the mechanisms of differences in efficacies of antidepressants.

Oral Administration of the Antimicrobial Peptide Mastoparan X Alleviates Enterohemorrhagic Escherichia coli-Induced Intestinal Inflammation and Regulates the Gut Microbiota

The gut microbiota plays an important role in intestinal immune system development and in driving inflammation. Antibiotic administration for therapeutic purposes causes an imbalance in the gut microbiota. Antimicrobial peptides can regulate the gut microbiota and maintain intestinal homeostasis. The aim of this study was to investigate the anti-inflammatory effects and regulation of the gut microbiota by the orally administered antimicrobial peptide mastoparan X (MPX). In this study, Escherichia coli was used to induce intestinal inflammation, and the results showed that MPX+ E. coli alleviated weight loss and intestinal pathological changes in necropsy specimens of E. coli-infected mice. MPX+ E. coli reduced the serum levels of the inflammation-related proteins interleukin-2, interleukin-6, tumour necrosis factor-α, myeloperoxidase, and lactate dehydrogenase on days 7 and 28. Furthermore, MPX+ E. coli increased the length of villi and reduced the infiltration of inflammatory cells into the jejunum and colon post infection. Scanning electron microscopy and transmission electron microscopy results showed that MPX could improve the morphology of jejunum villi and microvilli and increase tight junction protein levels. 16S rRNA sequencing analysis of caecal content samples showed that the species diversity and richness were lower in the E. coli-infected group. At the genus level, MPX+ E. coli significantly reduced the abundance of Bacteroidales and Alistipes and enhanced the relative abundance of Muribaculaceae. Alpha-diversity analyses (Shannon index) showed that MPX significantly increased the microbial diversity of mice. Overall, this study is the first to investigate the effects of oral administration of MPX on intestinal inflammation and the gut microbiota, providing a new perspective regarding the prevention of enteritis and maintenance of intestinal homeostasis.

The gut microbiome and cardiac surgery an unusual symphony

The relationship between the gut microbiome and various organ systems has gained interest throughout the scientific community in recent times. The understanding of these complex relationships has greatly improved with clinical benefits now being seen. Cardiopulmonary bypass (CPB) is a form of extracorporeal circulation that provides circulatory and respiratory support during cardiac surgery. This physiological support facilitates a still and bloodless field facilitating operations on the heart to be performed. Through various mechanisms CPB results in a systemic inflammatory response syndrome (SIRS). This response can vary from mild hypotension to multiple organ failure. It remains difficult to predict the degree to which a patient will experience SIRS post-operatively. The relationship between the composition of the gut microbiome and inflammatory processes associated with disease has been seen across several fields including gastroenterology, neurology, psychiatry and cardiology. To date, minimal research has been undertaken to examine the impact the gut microbiome has on outcomes following cardiac surgery. This review paper explores the pathophysiology behind the SIRS response associated with CPB for cardiac surgery and the hypothesis that a correlation exists between a patients gut microbiome composition and the degree of inflammatory response experienced following cardiac surgery.

Relationship between inflammatory-related cytokines with aortic dissection

Aortic dissection, characterized by severe intramural hematoma formation and acute endometrial rupture, is caused by excessive bleeding within the aortic wall or a severe tear within the intimal layer of the aorta, which subsequently promotes the separation or dissection in the layers of the aortic wall. Epidemiological surveys showed that aortic dissection was most observed among those patients from 55 to 80 years of age, with a prevalence of approximately 40 cases per 100,000 individuals per year, posing serious risks to future health and leading to high mortality. Other risk factors of aortic dissection progression contained dyslipidemia, hypertension, and genetic disorders, such as Marfan syndrome. Currently, emerging evidence indicates the pathological progression of aortic dissection is significantly complicated, which is correlated with the aberrant infiltration of pro-inflammatory cells into the aortic wall, subsequently facilitating the apoptosis of vascular smooth muscle cells (VSMCs) and inducing the aberrant expression of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interferon (IF). Other pro-inflammatory-related cytokines, including the colony-stimulating factor (CSF), chemotactic factor, and growth factor (GF), played an essential function in facilitating aortic dissection. Multiple studies focused on the important relationship between pro-inflammatory cytokines and aortic dissection, which could deepen the understanding of aortic dissection and further guide the therapeutic strategies in clinical practice. The present review elucidated pro-inflammatory cytokines' functions in modulating the risk of aortic dissection are summarized. Moreover, the emerging evidence that aimed to elucidate the potential mechanisms wherebyvarious pro-inflammatory cytokines affected the pathological development of aortic dissection was also listed.

Hydrogen gas ameliorates acute alcoholic liver injury via anti-inflammatory and antioxidant effects and regulation of intestinal microbiota

Alcoholic liver disease (ALD) is a globally prevalent liver-related disorder characterized by severe oxidative stress and inflammatory liver damage, for which no effective treatment is currently available. Hydrogen gas (H₂) has been demonstrated to be an efficient antioxidant in various diseases in animals as well as humans. However, the protective effects of H₂ on ALD and its underlying mechanisms remain to be elucidated. The present study demonstrated that H₂ inhalation ameliorated liver injury, and attenuated liver oxidative stress, inflammation, and steatosis in an ALD mouse model. Moreover, H₂ inhalation improved gut microbiota, including increasing the abundance of Lachnospiraceae and Clostridia, and decreasing the abundance of Prevotellaceae and Muribaculaceae, and also improved intestinal barrier integrity. Mechanistically, H₂ inhalation blocked activation of the LPS/TLR4/NF-κB pathway in liver. Notably, it was further demonstrated that the reshaped gut microbiota may accelerate alcohol metabolism, regulate lipid homeostasis and maintain immune balance by bacterial functional potential prediction (PICRUSt). Fecal microbiota transplantation from mice that had undergone H₂ inhalation significantly alleviated acute alcoholic liver injury. In summary, the present study showed that H₂ inhalation alleviated liver injury by reducing oxidative stress and inflammation, while also improving intestinal flora and enhancing the intestinal barrier. H₂ inhalation may serve as an effective intervention for preventing and treating ALD in a clinical context.

Pretreatment with IPA ameliorates colitis in mice: Colon transcriptome and fecal 16S amplicon profiling

3-Indolepropionic acid (IPA) is a tryptophan metabolite that has anti-inflammatory properties. The present study try to investigate the phylactic effects of IPA on dextran sodium sulfate (DSS)-induced colitis mice. The results showed that IPA pretreatment ameliorated the DSS-induced decrease in growth performance, and intestinal damage and enhanced immunity in mice. RNA-seq analysis of mouse colon samples revealed that the differentially expressed genes (DEGs) were mainly enriched in immune-related pathways. 16S rRNA sequencing showed that IPA pretreatment ameliorated DSS-induced colonic microbiota dysbiosis. Moreover, the expression levels of gut immune genes were positively correlated with the relative abundance of several probiotics, such as Alloprevotella and Catenibacterium. In conclusion, IPA alleviates DSS-induced acute colitis in mice by regulating inflammatory cytokines, balancing the colonic microbiota and modulating the expression of genes related to inflammation, which would also provide a theoretical basis for IPA as a strategy to improve intestinal health.

StrainXpress: strain aware metagenome assembly from short reads

Next-generation sequencing–based metagenomics has enabled to identify microorganisms in characteristic habitats without the need for lengthy cultivation. Importantly, clinically relevant phenomena such as resistance to medication, virulence or interactions with the environment can vary already within species. Therefore, a major current challenge is to reconstruct individual genomes from the sequencing reads at the level of strains, and not just the level of species. However, strains of one species can differ only by minor amounts of variants, which makes it difficult to distinguish them. Despite considerable recent progress, related approaches have remained fragmentary so far. Here, we present StrainXpress, as a comprehensive solution to the problem of strain aware metagenome assembly from next-generation sequencing reads. In experiments, StrainXpress reconstructs strain-specific genomes from metagenomes that involve up to >1000 strains and proves to successfully deal with poorly covered strains. The amount of reconstructed strain-specific sequence exceeds that of the current state-of-the-art approaches by on average 26.75% across all data sets (first quartile: 18.51%, median: 26.60%, third quartile: 35.05%).

ROESY and 13C NMR to distinguish between D- and L-rhamnose in the α-D-Manp-(1 → 4)-β-Rhap-(1 → 3) repeating motif

Many children suffering from autism spectrum disorder (ASD) experience gastrointestinal (GI) conditions. Enterocloster bolteae has been regularly detected in the stool of individuals suffering from GI symptoms and autism. Literature has suggested that E. bolteae strains WAL 16351 and WAL 14578 produce an immunogenic capsular polysaccharide (CPS) comprised of disaccharide repeating units: α-D-Man-(1 → 4)-β-Rha-(1 → 3) that could be used for the development of an immunotherapeutic vaccine. Ambiguity in the configuration of rhamnose led to the synthesis of tri- and disaccharide analogues containing D-rhamnose and L-rhamnose, respectively. ROESY-NMR spectra showed that CH₃-6 of rhamnose and H-2 of mannose in the L-Rha containing disaccharide gave correlation. No such correlation was seen between the CH₃-6 of rhamnose and the H-2 of mannose in the D-Rha containing trisaccharide. Molecular dynamics studies on hexasaccharide containing L-Rha or D-Rha confirmed that these structures adopt conformations resulting in different distances between the C6-rhamnose and the H-2 mannose of the preceding residue. We also demonstrate that assignment of the absolute configuration of the rhamnosyl residue in the β-Rhap-(1 → 3)-D-Man linkage can be determined using the ¹³C chemical shift of C-2 in of D-Mannose. While β-D-Rha will lead to an upfield shift of C-2 due to γ-gauche interaction between H-1 Rha and H-2 Man, β-L-Rha will not. Our results provide insights to distinguish between D- and L-rhamnose in the α-D-Manp-(1 → 4)-β-Rhap-(1 → 3) repeating motif.

Pediococcus acidilactici FZU106 alleviates high-fat diet-induced lipid metabolism disorder in association with the modulation of intestinal microbiota in hyperlipidemic rats

Probiotics have been proved to have beneficial effects in improving hyperlipidemia. The purpose of the current research was to investigate the ameliorative effects of Pediococcus acidilactici FZU106, isolated from the traditional brewing of Hongqu rice wine, on lipid metabolism and intestinal microbiota in high-fat diet (HFD)-induced hyperlipidemic rats. Results showed that P. acidilactici FZU106 intervention obviously inhibited the abnormal increase of body weight, ameliorated serum and liver biochemical parameters related to lipid metabolism and oxidative stress. Histopathological evaluation also showed that P. acidilactici FZU106 could significantly reduce the excessive lipid accumulation in liver caused by HFD-feeding. Furthermore, P. acidilactici FZU106 intervention significantly increased the short-chain fatty acids (SCFAs) levels in HFD-fed rats, which was closely related to the changes of intestinal microbial composition and metabolism. Intestinal microbiota profiling by high-throughput sequencing demonstrated that P. acidilactici FZU106 intervention evidently increased the proportion of Butyricicoccus, Pediococcus, Rothia, Globicatella and [Eubacterium]_coprostanoligenes_group, and decreased the proportion of Corynebacterium_1, Psychrobacter, Oscillospira, Facklamia, Pseudogracilibacillus, Clostridium_innocuum_group, Enteractinococcus and Erysipelothrix in HFD-fed rats. Additionally, P. acidilactici FZU106 significantly regulated the mRNA levels of liver genes (including CD36, CYP7A1, SREBP-1c, BSEP, LDLr and HMGCR) involved in lipid metabolism and bile acid homeostasis. Therefore, these findings support the possibility that P. acidilactici FZU106 has the potential to reduce the disturbance of lipid metabolism by regulating intestinal microflora and liver gene expression profiles.

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Pediococcus acidilactici FZU106 protects against hyperlipidemia.

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Pediococcus acidilactici FZU106 regulates serum and liver lipid levels.

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Pediococcus acidilactici FZU106 regulates intestinal microbial composition.

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Pediococcus acidilactici FZU106 regulates lipid metabolism related genes.

nnResearch progress on B cells and thoracic aortic aneurysm/dissection

Thoracic aortic aneurysm/dissection (TAAD) is a rare cardiovascular disease characterized by acute onset, rapid progression and high morbidity and mortality. One of the crucial factors leading to TAAD is the inflammatory response, which is regulated by many immune cell subgroups, including B cells. Compared with normal aortic tissue, the number of B cells in the aortic tissue of TAAD patients is significantly higher. Activated B cells participate in the vascular immune inflammatory response by producing antibodies and inflammatory factors and activating the complement system. These effects can lead to collagen degradation and aortic wall remodeling, both of which are the main pathologic characteristics of TAAD. Therefore, B cells play a key role in the occurrence and development of TAAD. B cells can be divided into B1 cells, B2 cells and regulatory B cells, which have different mechanisms of action in TAAD. This article will review the role of B cells in TAAD from the perspective of three different subtypes of B cells.

Bacterial metabolites and cardiovascular risk in children with chronic kidney disease

Cardiovascular complications are the major cause of the marked morbidity and mortality associated with chronic kidney disease (CKD). The classical cardiovascular risk factors such as diabetes and hypertension undoubtedly play a role in the development of cardiovascular disease (CVD) in adult CKD patients; however, CVD is just as prominent in children with CKD who do not have these risk factors. Hence, the CKD-specific pathophysiology of CVD remains incompletely understood. In light of this, studying children with CKD presents a unique opportunity to analyze CKD-associated mechanisms of CVD more specifically and could help to unveil novel therapeutic targets.

Here, we comprehensively review the interaction of the human gut microbiome and the microbial metabolism of nutrients with host immunity and cardiovascular end-organ damage. The human gut microbiome is evolutionary conditioned and modified throughout life by endogenous factors as well as environmental factors. Chronic diseases, such as CKD, cause significant disruption to the composition and function of the gut microbiome and lead to disease-associated dysbiosis. This dysbiosis and the accompanying loss of biochemical homeostasis in the epithelial cells of the colon can be the result of poor diet (e.g., low-fiber intake), medications, and underlying disease. As a result of dysbiosis, bacteria promoting proteolytic fermentation increase and those for saccharolytic fermentation decrease and the integrity of the gut barrier is perturbed (leaky gut). These changes disrupt local metabolite homeostasis in the gut and decrease productions of the beneficial short-chain fatty acids (SCFAs). Moreover, the enhanced proteolytic fermentation generates unhealthy levels of microbially derived toxic metabolites, which further accumulate in the systemic circulation as a consequence of impaired kidney function. We describe possible mechanisms involved in the increased systemic inflammation in CKD that is associated with the combined effect of SCFA deficiency and accumulation of uremic toxins. In the future, a more comprehensive and mechanistic understanding of the gut–kidney–heart interaction, mediated largely by immune dysregulation and inflammation, might allow us to target the gut microbiome more specifically in order to attenuate CKD-associated comorbidities.

The microbiome’s relationship with congenital heart disease: more than a gut feeling

Patients with congenital heart disease (CHD) are at risk for developing intestinal dysbiosis and intestinal epithelial barrier dysfunction due to abnormal gut perfusion or hypoxemia in the context of low cardiac output or cyanosis. Intestinal dysbiosis may contribute to systemic inflammation thereby worsening clinical outcomes in this patient population. Despite significant advances in the management and survival of patients with CHD, morbidity remains significant and questions have arisen as to the role of the microbiome in the inflammatory process. Intestinal dysbiosis and barrier dysfunction experienced in this patient population are increasingly implicated in critical illness. This review highlights possible CHD-microbiome interactions, illustrates underlying signaling mechanisms, and discusses future directions and therapeutic translation of the basic research.

Effects of Sevoflurane Inhalation Anesthesia on the Intestinal Microbiome in Mice

In recent years, more and more attention has been paid to intestinal microbiome. Almost all operations will go through the anesthesia process, but it is not clear whether the intervention of anesthesia alone will affect the change in the intestinal microbiome. The purpose of this study was to verify the effect of sevoflurane inhalation anesthesia on the intestinal microbiome. The animal in the experimental group was used to provide sevoflurane inhalation anesthesia for 4 hours. The control group was not intervened. The feces of the experimental group and the control group were collected on the 1st, 3rd, 7th and 14th days after anesthesia. Sevoflurane inhalation anesthesia will cause changes in the intestinal microbiome of mice. It appears on the 1st day after anesthesia and is most obvious on the 7th day. The specific manifestation is that the abundance of microbiome and the diversity of the microbiome is reduced. At the same time, Untargeted metabonomics showed that compared with the control group, the experimental group had more increased metabolites related to the different microbiome, among which 5-methylthioadenosine was related to the central nervous system. Subsequently, the intestinal microbiome diversity of mice showed a trend of recovery on the 14th day. At the genus level, the fecal samples obtained on the 14th day after anesthesia exhibited significantly increased abundances of Bacteroides, Alloprevotella, and Akkermansia and significantly decreased abundances of Lactobacillus compared with the samples obtained on the 1st day after anesthesia. However, the abundance of differential bacteria did not recover with the changing trend of diversity. Therefore, we believe that sevoflurane inhalation anesthesia is associated with changes in the internal microbiome and metabolites, and this change may be completed through the brain-gut axis, while sevoflurane inhalation anesthesia may change the intestinal microbiome for as long as 14 days or longer.

Antidepressants fluoxetine and amitriptyline induce alterations in intestinal microbiota and gut microbiome function in rats exposed to chronic unpredictable mild stress

Antidepressant medications are known to modulate the central nervous system, and gut microbiota can play a role in depression via microbiota-gut-brain axis. But the impact of antidepressants on gut microbiota function and composition remains poorly understood. Thus this study assessed the effect of serotonin reuptake inhibitor antidepressant fluoxetine (Flu) and tricyclic antidepressant amitriptyline (Ami) administration on gut microbiota composition, diversity, and species abundance, along with microbial function in a chronic unpredictable mild stress (CUMS)-induced depression rat model. Oral administration of Ami and Flu significantly altered the overall gut microbiota profile of CUMS-induced rats, as assessed using the permutational multivariate analysis of variance test. At the phylum level, 6-week of antidepressant treatment led to a decreased Firmicutes/Bacteroidetes ratio due to an enhanced Bacteroidetes and reduced Firmicutes relative abundance. Flu was more potent than Ami at altering the Firmicutes and Bacteroidetes levels in the CUMS rats. At the family level, both antidepressants significantly increased the abundance of Porphyromonadaceae. However, an increased Bacteroidaceae level was significantly associated with Ami, not Flu treatment. Furthermore, at the genus level, an increase in the relative abundance of Parabacteroides, Butyricimonas, and Alistipes was observed following Ami and Flu treatment. Subsequent metagenomics and bioinformatics analysis further indicated that Ami and Flu likely also modulated metabolic pathways, such as those involved in carbohydrate metabolism, membrane transport, and signal transduction. Additionally, both antidepressants affected antibiotic resistome, such as for aminoglycoside (aph3iiiA), multidrug (mdtK, mdtP, mdtH, mdtG, acrA), and tetracycline (tetM) resistance in CUMS rats. These data clearly illustrated the direct impact of oral administration of Flu and Ami on the gut microbiome, thus set up the foundation to reveal more insights on the therapeutic function of the antidepressants and their overall contribution to host health.

Effect of Combined Live Probiotics Alleviating the Gastrointestinal Symptoms of Functional Bowel Disorders

Objective

Changes of the gut microbiota are related to the pathogenesis of functional bowel disorders (FBDs), and probiotic supplementation may be an effective treatment option. Therefore, we aimed to investigate the effect of combined live probiotics on the gastrointestinal symptoms of FBDs via altering the gut microbiota.

Methods

Patients with the gastrointestinal symptoms of FBDs attending the Outpatient Department, from July to November 2019, were recruited. After the bowel preparation with polyethylene glycol electrolyte powder and colonoscopy, patients with normal result of colonoscopy were randomly divided into the probiotics group and control group. Patients in the probiotics group were prescribed with combined live Bacillus subtilis and Enterococcus faecium enteric-coated capsules for 4 weeks. Small intestinal bacteria overgrowth (SIBO) was measured by lactulose hydrogen breath test, and the microbial DNA was extracted from the fecal samples and the bacteria were classified by 16S rDNA gene amplicon sequencing.

Results

Twenty-five patients of each group were recruited, and there was no significant difference between the probiotics and control groups on baseline gastrointestinal symptom rating scale (GSRS), positive rate of SIBO, and relative abundances of the gut microbiota at the phylum level. After 4 weeks of treatment, the values of the probiotics and control groups were as follows: GSRS 1.4 ± 1.4 and 3.6 ± 1.6 and positive rate of SIBO 28.0% and 56.0%, respectively. The median relative abundances of the gut microbiota were 1.01% and 5.03% Actinobacteria and 43.80% and 35.17% Bacteroidetes at the phylum level; 0.76% and 3.29% Bifidobacterium, 0.13% and 0.89% Cillinsella, 0.03% and 0.01% Enterococcus, 0.18% and 0.36% Lachnospiraceae, 0.10% and 0.16% Ruminococcus torques group, 1.31% and 2.44% Blautia, and 0.83% and 2.02% Fusicatenibacter at the genus level (P < 0.05), respectively.

Conclusion

Combined live probiotic supplementation after the bowel preparation can alter the gut microbiota, decontaminate SIBO, and alleviate the gastrointestinal symptoms of FBDs. This trial is registered with ChiCTR1900026472.

Bacteroides thetaiotaomicron-Infecting Bacteriophage Isolates Inform Sequence-Based Host Range Predictions

Our emerging view of the gut microbiome largely focuses on bacteria, while less is known about other microbial components, such as bacteriophages (phages). Though phages are abundant in the gut, very few phages have been isolated from this ecosystem. Here, we report the genomes of 27 phages from the United States and Bangladesh that infect the prevalent human gut bacterium Bacteroides thetaiotaomicron. These phages are mostly distinct from previously sequenced phages with the exception of two, which are crAss-like phages. We compare these isolates to existing human gut metagenomes, revealing similarities to previously inferred phages and additional unexplored phage diversity. Finally, we use host tropisms of these phages to identify alleles of phage structural genes associated with infectivity. This work provides a detailed view of the gut's "viral dark matter" and a framework for future efforts to further integrate isolation- and sequencing-focused efforts to understand gut-resident phages.

Gastrointestinal surgery and the gut microbiome: a systematic literature review

BACKGROUND/OBJECTIVES

The impact of gastrointestinal surgery on the profile of the human gut microbiome is not fully understood. This review aimed to identify whether there is a change to the profile of the gut microbiome as a result of gastrointestinal surgery.

SUBJECTS/METHODS

In August 2018, a systematic literature search was conducted in Medline, PreMedline, Embase, CINAHL and The Cochrane Register of Clinical Trials, identifying and critically appraising studies which investigated changes to gut microbiome pre- and post-gastrointestinal surgery.

RESULTS

Of 2512 results, 14 studies were included for analysis. All studies reported post-surgical change to the microbiome. In 9 of the 14 studies, prevalence of specific bacteria had significantly changed after surgery. Improved outcome was associated with higher levels of beneficial bacteria and greater microbiome diversity post-surgery.

CONCLUSION

There were methodological limitations in the included studies leading to uncertainty regarding the impact of gastrointestinal surgery alone on the microbiome profile. An ideal future model for research should encompass case-controlled or cohort design with longer term follow-up in a homogeneous patient group. Future research should seek to clarify the gold standard testing method and standardised timing for post-surgical microbiome sample collection. It is imperative that controls for confounders be put in place to attempt to identify the true association between gastrointestinal surgery and changes to gut microbiome.

IDO and Kynurenine Metabolites in Peripheral and CNS Disorders

The importance of the kynurenine pathway in normal immune system function has led to an appreciation of its possible contribution to autoimmune disorders such as rheumatoid arthritis. Indoleamine-2,3-dioxygenase (IDO) activity exerts a protective function, limiting the severity of experimental arthritis, whereas deletion or inhibition exacerbates the symptoms. Other chronic disorder with an inflammatory component, such as atherosclerosis, are also suppressed by IDO activity. It is suggested that this overall anti-inflammatory activity is mediated by a change in the relative production or activity of Th17 and regulatory T cell populations. Kynurenines may play an anti-inflammatory role also in CNS disorders such as Huntington's disease, Alzheimer's disease and multiple sclerosis, in which signs of inflammation and neurodegeneration are involved. The possibility is discussed that in Huntington's disease kynurenines interact with other anti-inflammatory molecules such as Human Lymphocyte Antigen-G which may be relevant in other disorders. Kynurenine involvement may account for the protection afforded to animals with cerebral malaria and trypanosomiasis when they are treated with an inhibitor of kynurenine-3-monoxygenase (KMO). There is some evidence that changes in IL-10 may contribute to this protection and the relationship between kynurenines and IL-10 in arthritis and other inflammatory conditions should be explored. In addition, metabolites of kynurenine downstream of KMO, such as anthranilic acid and 3-hydroxy-anthranilic acid can influence inflammation, and the ratio of these compounds is a valuable biomarker of inflammatory status although the underlying molecular mechanisms of the changes require clarification. Hence it is essential that more effort be expended to identify their sites of action as potential targets for drug development. Finally, we discuss increasing awareness of the epigenetic regulation of IDO, for example by DNA methylation, a phenomenon which may explain differences between individuals in their susceptibility to arthritis and other inflammatory disorders.

Peri-operative risk factors for in-hospital mortality in acute type A aortic dissection

Background

Acute type A aortic dissection (TAAD) is cardiovascular emergency and requires surgical interventions. In-hospital mortality rate of surgical-treated TAAD patients remains high. We aim to examine the prognostic implications of peri-operative parameters to identify high-risk patient for in-hospital mortality.

Methods

A total of 264 surgically treated TAAD patients were included in this study. The association between in-hospital mortality and peri-operative parameters were examined.

Results

Thirty patients (11.36%) died during hospitalization. Patients with higher Apache II score had a significantly higher rate of in-hospital mortality when compared with patients scored ≤20 in unadjusted model [Score 21-25: HR =12.9 (1.7-100.8), P=0.0148; Score >25: HR =94.5 (12.6-707.6), P<0.0001]. Patients with Sbp >120 mmHg, Cr >200 mmol/L (both at admission and after surgery), BUN >8.2 mmol/L (both at admission and after surgery), AST >80 µ/L, aortic cross-clamping time >120 min and cardiopulmonary bypass time (CPBT) >230 min were also significantly related to higher rate of in-hospital mortality in univariate analysis. In multivariable analysis, APACHE II score [Score 21-25: HR =9.5 (1.2-74.4), P=0.032; Score >25: HR =51.0 (6.7-387.7), P=0.0001], AST >80 µmol/L [HR =2.3 (1.1-4.8), P=0.0251], aortic cross-clamping time >120 min (HR =2.9 (1.1-7.7), P=0.0315) remained significant in predicting TAAD in-hospital mortality.

Conclusions

APACHE II score could be a useful tool to predict TAAD in-hospital mortality. AST >80 µ/L and aortic cross-clamping time >120 min were also independent predictors.

Age- and diet-specific effects of chronic exposure to chlorpyrifos on hormones, inflammation and gut microbiota in rats

Chlorpyrifos is a pesticide frequently detected in food and has been reported to disturb endocrine and gut health, which was regulated by gut microbiota and enteroendocrine cells. In this study, newly weaned (3 week) and adult (8 week) male rats fed a normal- or high- fat diet were chronically exposed to 0.3 mg chlorpyrifos/kg bodyweight/day. The effects of chlorpyrifos exposure on serum hormone levels, proinflammatory cytokines and gut microbiota were evaluated. Chronic exposure to chlorpyrifos significantly decreased the concentrations of luteinizing hormone, follicule stimulating hormone and testosterone, which was found only in the normal-fat diet. The counteracted effect of high-fat diet was also found in gut hormones and proinflammatory cytokines. Significantly higher concentrations of glucagon-like peptide-1, pancreatic polypeptide, peptide tyrosine tyrosine (PYY), ghrelin, gastric inhibitory poly-peptide, IL-6, monocyte chemoattractant protein-1, and TNF-α were found in rats exposed to chlorpyrifos beginning at newly weaned, whereas only the PYY, ghrelin and IL-6 concentrations increased significantly in rats exposed in adulthood. Furthermore, a decrease in epinephrine induced by chlorpyrifos exposure was found in rats exposed to chlorpyrifos beginning at newly weaned, regardless of their diet. Chlorpyrifos-induced disturbances in the microbiome community structure were more apparent in rats fed a high-fat diet and exposed beginning at newly weaned. The affected bacteria included short-chain fatty acid-producing bacteria (Romboutsia, Turicibacter, Clostridium sensu stricto 1, norank_f_Coriobacteriaceae, Faecalibaculum, Parasutterella and norank_f__Erysipelotrichaceae), testosterone-related genus (Turicibacter, Brevibacterium), pathogenic bacteria (Streptococcus), and inflammation-related bacteria (unclassified_f__Ruminococcaceae, Ruminococcaceae_UCG-009, Parasutterella, Oscillibacter), which regulated the endocrine system via the hypothalamic-pituitary-adrenal axis, as well as the immune response and gut barrier. Early exposure accelerated the endocrine-disturbing effect and immune responses of chlorpyrifos, although these effects can be eased or recovered by a high-fat diet. This study helped clarify the relationship between disrupted endocrine function and gut microbiota dysbiosis induced by food contaminants such as pesticides.

The Role of the Small Bowel in Unintentional Weight Loss after Treatment of Upper Gastrointestinal Cancers

Upper gastrointestinal (GI) cancers are responsible for significant mortality and morbidity worldwide. To date, most of the studies focused on the treatments’ efficacy and post-treatment survival rate. As treatments improve, more patients survive long term, and thus the accompanying complications including unintentional weight loss are becoming more important. Unintentional weight loss is defined as >5% of body weight loss within 6–12 months. Malignancies, particularly GI cancers, are diagnosed in approximately 25% of patients who present with unintentional weight loss. Whereas some recent studies discuss pathophysiological mechanisms and new promising therapies of cancer cachexia, there is a lack of studies regarding the underlying mechanism of unintentional weight loss in patients who are tumor free and where cancer cachexia has been excluded. The small bowel is a central hub in metabolic regulation, energy homeostasis, and body weight control throughout the microbiota-gut-brain axis. In this narrative review article, the authors discussed the impacts of upper GI cancers’ treatment modalities on the small bowel which may lead to unintentional weight loss and some new promising therapeutic agents to treat unintentional weight loss in long term survivors after upper GI operations with curative intent.

Fluoxetine-induced alteration of murine gut microbial community structure: evidence for a microbial endocrinology-based mechanism of action responsible for fluoxetine-induced side effects

Background

Depression and major depressive disorder affect 25% of the population. First line treatment utilizing selective serotonin reuptake inhibitors (SSRIs) have met with limited success due to well-recognized negative side effects which include weight gain or loss. This inability to control unwanted side effects often result in patients stopping their antidepressant medications. The mechanisms underlying the failure of SSRIs are incompletely understood.

Methods

Male CF-1 mice (5 weeks of age, N = 10 per group) were per orally administered fluoxetine (20 mg per kg body weight) or diluent daily for 29 days. During this time fecal specimens were collected at three defined time points (0, 15 and 29 days). At the conclusion of the 29-day dosing regimen, animals were subjected to two behavioral assessments. For bacterial identification of the microbiota, 16S rRNA gene sequencing was performed on 60 fecal specimens (three specimens per mouse time course, N = 20 mice) using Illumina MiSeq. Analysis of community sequence data was done using mothur and LEfSe bioinformatic software packages.

Results

Daily per oral administration of fluoxetine for 29 days to male mice resulted in a significant, time dependent, alteration in microbial communities accompanying changes in body weight. The calculated species richness and diversity indicators of the murine fecal microbial communities were inconsistent and not significantly different between the groups. Among the phylotypes decreased in abundance due to fluoxetine administration were Lactobacillus johnsonii and Bacteroidales S24-7 which belong to phyla associated with regulation of body mass. The observed changes in body weight due to fluoxetine administration mimicked the dramatic shifts in weight gain/loss that has been observed in humans. Further, at the conclusion of the 29-day dosing regimen fluoxetine-dosed animals evidenced a mild anxiogenic-like behavior.

Discussion

We report that the most widely used antidepressant, fluoxetine, which is an SSRI-type drug, results in the selective depletion of gut microbiota, specifically the Lactobacilli which are involved in the regulation of body weight. Concomitantly, fluoxetine administration increases the abundance of phylotypes related to dysbiosis. Since Lactobacilli have been previously shown to possess a known biogenic amine transporter that regulates the uptake of fluoxetine, it is proposed that a microbial endocrinology-based mechanistic pathway is responsible for the ability of SSRIs to selectively negatively impact beneficial microbiota. The results of this study therefore suggest that the negative clinical side effects due to fluoxetine administration may be due to alterations in gut microbiota. Further, the data also suggests that supplementation of bacterial genera directly affected by fluoxetine administration may prove useful in ameliorating some of the well-known side effects of chronic fluoxetine administration such as weight alterations.

Cytokines in aortic dissection

Aortic dissection (AD) is one of the most dangerous forms of vascular disease, characterized by endometrial rupture and intramural hematoma formation. Generally, the pathological process is complicated and closely related to the infiltration of inflammatory cells into the aortic wall and apoptosis of vascular smooth muscle cells. Currently, multiple cytokines, including interleukins, interferon, the tumor necrosis factor superfamily, colony stimulating factor, chemotactic factor, growth factor and so on, have all been demonstrated to play a critical role in AD. Additionally, studies of the link between cytokines and AD could deepen our understanding of the disease and may guide future treatment therapies; therefore, this review focuses on the role of cytokines in AD.