Microbial Modulation of Coagulation Disorders in Venous Thromboembolism

Contribution of staphylococcal virulence factors in the pathogenesis of thrombosis

Staphylococci are responsible for many infections in humans, starting with skin and soft tissue infections and finishing with invasive diseases such as endocarditis, sepsis and pneumonia, which lead to high mortality. Patients with sepsis often demonstrate activated clotting pathways, decreased levels of anticoagulants, decreased fibrinolysis, activated endothelial surfaces and activated platelets. This results in disseminated intravascular coagulation and formation of a microthrombus, which can lead to a multiorgan failure. This review describes various staphylococcal virulence factors that contribute to vascular thrombosis, including deep vein thrombosis in infected patients. The article presents mechanisms of action of different factors released by bacteria in various host defense lines, which in turn can lead to formation of blood clots in the vessels.

The gut microbe-derived metabolite trimethylamine-N-oxide induces aortic valve fibrosis via PERK/ATF-4 and IRE-1α/XBP-1s signaling in vitro and in vivo

BACKGROUND AND AIMS

The gut microbe-derived metabolite trimethylamine-N-oxide (TMAO) has been implicated in the development of cardiovascular fibrosis. Endoplasmic reticulum (ER) stress occurs after the dysfunction of ER and its structure. The three signals PERK/ATF-4, IRE-1α/XBP-1s and ATF6 are activated upon ER stress. Recent reports have suggested that the activation of PERK/ATF-4 and IRE-1α/XBP-1s signaling contributes to cardiovascular fibrosis. However, whether TMAO mediates aortic valve fibrosis by activating PERK/ATF-4 and IRE-1α/XBP-1s signaling remains unclear.

METHODS

Human aortic valve interstitial cells (AVICs) were isolated from aortic valve leaflets. PERK IRE-1α, ATF-4, XBP-1s and CHOP expression, and production of collagen Ⅰ and TGF-β1 were analyzed following treatment with TMAO. The role of PERK/ATF-4 and IRE-1α/XBP-1s signaling pathways in TMAO-induced fibrotic formation was determined using inhibitors and small interfering RNA.

RESULTS

Diseased valves produced greater levels of ATF-4, XBP-1, collagen Ⅰ and TGF-β1. Interestingly, diseased cells exhibited augmented PERK/ATF-4 and IRE-1α/XBP-1s activation after TMAO stimulation. Inhibition and silencing of PERK/ATF-4 and IRE-1α/XBP-1s each resulted in enhanced suppression of TMAO-induced fibrogenic activity in diseased cells. Mice treated with dietary choline supplementation had substantially increased TMAO levels and aortic valve fibrosis, which were reduced by 3,3-dimethyl-1-butanol (DMB, an inhibitor of trimethylamine formation) treatment. Moreover, a high-choline and high-fat diet remodeled the gut microbiota in mice.

CONCLUSIONS

TMAO promoted aortic valve fibrosis through activation of PERK/ATF-4 and IRE-1α/XBP-1s signaling pathways in vitro and in vivo. Modulation of diet, gut microbiota, TMAO, PERK/ATF-4 and IRE1-α/XBP-1s may be a promising approach to prevent aortic valve fibrosis.

Serological short-chain fatty acid and trimethylamine N-oxide microbial metabolite imbalances in young adults with acute myocardial infarction

Acute myocardial infarction (AMI) is associated with systemic inflammatory processes and metabolic alterations. Microbial-derived metabolites, such as short-chain fatty acids and trimethylamine N-oxide (TMAO), have emerged in recent years as key players in the modulation of inflammation, with potential implications for cardiovascular diseases. We performed a prospective observational study that monitored the serological concentration of bacterial metabolites in 45 young patients (<55 years) without cardiovascular risk factors but with AMI, at hospital admission and at 3 months of follow-up, and compared them with a control group. TMAO and acetate levels were significantly higher in AMI, whereas butyrate and propionate were significantly lower. The acetate/propionate ratio showed the most discrimination between AMI and controls by receiver operating characteristic analysis (area under the curve 0.769, P < 0.0001). A multivariate logistic regression model revealed that this ratio was independently associated with AMI. Short-chain fatty acid concentrations, but not TMAO, exhibited significant correlations with inflammatory and coagulation parameters. Three months after the acute AMI event, all metabolite levels returned to those observed in healthy controls except butyrate. In conclusion, our study reveals disturbances of the serological concentration of microbiota-derived metabolites in AMI that are also related to inflammatory and coagulation parameters. These findings highlight an interesting field of study in the potential role of microbial metabolites from gut in cardiovascular disease.

Early Administration of Vancomycin Inhibits Pulmonary Embolism by Remodeling Gut Microbiota

Pulmonary embolism (PE) is a common and potentially fatal condition in the emergency department, and early identification of modifiable risk factors for prevention and management is highly desirable. Although gut dysbiosis is associated with a high incidence of venous thromboembolism, the role and mechanisms of the gut microbiome in the pathogenesis of venous thromboembolism, especially PE, remain unexplored. Here, we attempted to elucidate the benefits of the gut microbiome in the pathogenesis of PE using multiple antibiotics and fecal microbiota transplantation (FMT) for early intervention in a classical mouse model of PE. The results showed that early administration of various antibiotics (except ampicillin) could inhibit pulmonary thrombosis to a certain extent and reduced mortality in young and old mice with PE. Among them, vancomycin has the best inhibitory effect on PE. With the help of gut microbiota sequencing analysis, we found that antibiotic treatment can reshape the gut microbiota; especially vancomycin can significantly improve the gut microbiota structure in PE mice. Furthermore, FMT could transfer vancomycin-modified gut microbes into mice and inhibit the pathogenesis of PE, possibly due to increased intestinal colonization by Parasutterella. These data elucidate the underlying molecular mechanism by which early administration of vancomycin can remodel the gut microbiota to suppress PE, providing new clues for clinical optimization and development of PE prevention strategies.

The Underlying Molecular Basis and Mechanisms of Venous Thrombosis in Patients with Osteomyelitis: A Data-Driven Analysis

Objective

Osteomyelitis (OM) is one of the most risky and challenging diseases. Emerging evidence indicates OM is a risk factor for increasing incidence of venous thromboembolism (VTE) development. However, the mechanisms have not been intensively investigated.

Methods

The OM-related dataset GSE30119 and VTE-related datasets GSE19151 and GSE48000 were downloaded from the Gene Expression Omnibus (GEO) database and analyzed to identify the differentially expressed genes (DEGs) (OMGs1 and VTEGs1, respectively). Functional enrichment analyses of Gene Ontology (GO) terms were performed. VTEGs2 and OMGs2 sharing the common GO biological process (GO-BP) ontology between OMGs1 and VTEGs1 were detected. The TRRUST database was used to identify the upstream transcription factors (TFs) that regulate VTEGs2 and OMGs2. The protein-protein interaction (PPI) network between VTEGs2 and OMGs2 was constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) database and then visualized in Cytoscape. Topological properties of the PPI network were calculated by NetworkAnalyzer. The Molecular Complex Detection (MCODE) plugin was utilized to perform module analysis and choose the hub modules of the PPI network.

Results

A total of 587 OMGs1 and 382 VTEGs1 were identified from the related dataset, respectively. GO-BP terms of OMGs1 and shared DGEs1 were mainly enriched in the neutrophil-related immune response process, and the shared GO-BP terms of OMGs1 and VTEGs1 seemed to be focused on cell activation, immune, defense, and inflammatory response to stress or biotic stimulus. 230 VTEGs2, 333 OMGs2, and 13 shared DEGs2 were detected. 3 TF-target gene pairs (SP1-LSP1, SPI1-FCGR1A, and STAT1-FCGR1A) were identified. The PPI network contained 1611 interactions among 467 nodes. The top 10 hub proteins were TP53, IL4, MPO, ELANE, FOS, CD86, HP, SOCS3, ICAM1, and SNRPG. Several core nodes (such as MPO, ELANE, and CAMP) were essential components of the neutrophil extracellular traps (NETs) network.

Conclusion

This is the first data-mining study to explore shared signatures between OM and VTE by the integrated bioinformatic approach, which can help uncover potential biomarkers and therapeutic targets of OM-related VTE.

The Association of Helicobacter pylori, Eradication, and Early Complications of Laparoscopic Sleeve Gastrectomy

PURPOSE

Laparoscopic sleeve gastrectomy (SG) is a common and effective bariatric surgery, with low postoperative complication rates. It is important to define modifiable risk factors for complications. The possible association of Helicobacter pylori (HP) on SG outcomes is still being investigated. We aimed to examine HP prevalence in SG specimens, the association to early (30-day) complications, and impact of preoperative HP eradication on outcomes.

MATERIALS AND METHODS

This is a retrospective analysis of all consecutive patients who underwent SG between January 2012 and December 2020 in a single bariatric center. Data were retrieved from our prospectively maintained patient registry database. The 30-day outcomes were compared according to the HP status of the resected specimen: positive and negative, with or without preoperative HP eradication therapy.

RESULTS

There were 1985 patients; of them, 179 patients were HP positive and 1806 were HP negative in resected specimens. The overall early complication and major (Clavien-Dindo ≥ 3) complication rates were 8.6% and 3.2% (p = 0.48 and p = 0.21), respectively. A total of 111 patients were HP positive on preoperative endoscopic biopsy and received eradication therapy. All were HP negative on preoperative urea breath test, and 65.45% had HP negative resected specimens. HP eradication did not affect overall and major complications (p = 0.68 and p = 0.48, respectively).

CONCLUSION

The presence of HP does not seem to affect the early outcomes of SG. HP eradication does not change the early postoperative course either. Therefore, the role of routine preoperative HP screening may be limited, and eradication can be completed following SG.

TMAO and Gut Microbial-Derived Metabolites TML and γBB Are Not Associated with Thrombotic Risk in Patients with Venous Thromboembolism

Background: The present work evaluates the association between circulating concentrations of Trimethylamine-N-oxide (TMAO), gamma butyrobetaine (γBB), and trimetyllisine (TML) in controls and patients with venous thromboembolism (VTE) with coagulation parameters. Methods: The study involved 54 VTE patients and 57 controls. Platelet function, platelet hyperreactivity, platelet adhesiveness, thrombosis-associated parameters, and thrombin generation parameters were studied. Plasma TMAO, γBB, and TML determination was performed using an ultra-high-performance liquid chromatography system coupled with mass spectrometry. Results: No differences were found for TMAO, γBB, or TML concentrations between controls and VTE patients. In thrombin generation tests, TMAO, γBB, and TML showed a positive correlation with lag time and time to peak. TMAO, γBB, and TML negatively correlated with peak height. No significant differences were observed regarding TMAO, γBB, and TML concentrations between the two blood withdrawals, nor when the control and VTE patients were analyzed separately. No correlation was observed between these gut metabolites and platelet function parameters. Conclusions: No differences were found regarding TMAO, γBB, and TML concentrations between the control and VTE groups. Some correlations were found; however, they were mild or went in the opposite direction of what would be expected if TMAO and its derivatives were related to VTE risk.

Elucidation of Cellular Contributions to Heparin-Induced Thrombocytopenia Using Omic Approaches

Heparin-induced thrombocytopenia (HIT) is an unpredictable, complex, immune-mediated adverse drug reaction associated with a high mortality. Despite decades of research into HIT, fundamental knowledge gaps persist regarding HIT likely due to the complex and unusual nature of the HIT immune response. Such knowledge gaps include the identity of a HIT immunogen, the intrinsic roles of various cell types and their interactions, and the molecular basis that distinguishes pathogenic and non-pathogenic PF4/heparin antibodies. While a key feature of HIT, thrombocytopenia, implicates platelets as a seminal cell fragment in HIT pathogenesis, strong evidence exists for critical roles of multiple cell types. The rise in omic technologies over the last decade has resulted in a number of agnostic, whole system approaches for biological research that may be especially informative for complex phenotypes. Applying multi-omics techniques to HIT has the potential to bring new insights into HIT pathophysiology and identify biomarkers with clinical utility. In this review, we review the clinical, immunological, and molecular features of HIT with emphasis on key cell types and their roles. We then address the applicability of several omic techniques underutilized in HIT, which have the potential to fill knowledge gaps related to HIT biology.

Gut Microbiota-Derived Inflammation-Related Serum Metabolites as Potential Biomarkers for Major Depressive Disorder

Background

Although many works have been conducted to explore the biomarkers for diagnosing major depressive disorder (MDD), the widely accepted biomarkers are still not identified. Thus, the combined application of serum metabolomics and fecal microbial communities was used to identify gut microbiota-derived inflammation-related serum metabolites as potential biomarkers for MDD.

Methods

MDD patients and healthy controls (HCs) were included in this study. Both serum samples and fecal samples were collected. The liquid chromatography mass spectrometry (LC-MS) was used to detect the metabolites in serum samples, and the 16S rRNA gene sequencing was used to analyze the gut microbiota compositions in fecal samples.

Results

Totally, 60 MDD patients and 60 HCs were recruited. The 24 differential serum metabolites were identified, and 10 of these were inflammation-related metabolites. Three significantly affected inflammation-related pathways were identified using differential metabolites. The 17 differential genera were identified, and 14 of these genera belonged to phyla Firmicutes. Four significantly affected inflammation-related pathways were identified using differential genera. Five inflammation-related metabolites (LysoPC(16:0), deoxycholic acid, docosahexaenoic acid, taurocholic acid and LysoPC(20:0)) were identified as potential biomarkers. These potential biomarkers had significant correlations with genera belonged to phyla Firmicutes. The panel consisting of these biomarkers could effectively distinguish MDD patients from HCs with an area under the curve (AUC) of 0.95 in training set and 0.92 in testing set.

Conclusion

These findings suggested that the disturbance of phyla Firmicutes might be involved in the onset of depression by regulating host’s inflammatory response, and these potential biomarkers could be useful for future investigating the objective methods for diagnosing MDD.

Identification of a novel mortality-associated Helicobacter species in gopher tortoises (Gopherus polyphemus), qPCR test development and validation, and correlation with mortality in a wildlife rehabilitation population

The genus Helicobacter includes spiral-shaped bacteria in the phylum Proteobacteria, class Epsilonproteobacteria, order Campylobacteriales, that have been associated with disease in animals, including reptiles. Three wild gopher tortoise (Gopherus polyphemus) index cases presented between 2012 and 2019 with nasal discharge, lethargy, and weight loss. Cytological examination of nasal discharge from all 3 tortoises identified marked heterophilic and mild histiocytic rhinitis with abundant extracellular and phagocytized spiral shaped bacteria that stained positive with Warthin-Starry stain. Polymerase chain reaction (PCR) and sequencing of the 16S rRNA gene revealed this to be a novel Helicobacter species. Two tortoises died despite treatment attempts, and the third was moribund and was euthanized. Histological examination of the nasal mucosa (n = 3) showed granulocytic to lymphocytic rhinitis with variable mucosal hyperplasia, erosion, and ulceration; Warthin-Starry staining highlighted the presence of spiral bacteria in the untreated tortoise. Genus-specific primers were designed, and the gyrA and groEL genes were amplified by PCR and sequenced. Phylogenetic analysis shows that this organism and other previously characterized Helicobacter from tortoises form a clade. Development and cross-validation of two qPCR diagnostic assays for the gyrA and groEL genes showed significant correlation of the results of two assays (P < 0.0001). These assays were used to survey nasal wash samples from 31 rehabilitating gopher tortoises. Mortality of tortoises significantly correlated with higher Helicobacter loads detected by qPCR (P = 0.028). Appropriate quarantine protocols for tortoises during rehabilitation should consider this organism. Upper respiratory disease in tortoises may involve complex microbial ecology; factors beyond Mycoplasmopsis (Mycoplasma) agassizii should be taken into account.

Uremic Toxins and Their Relation with Oxidative Stress Induced in Patients with CKD

The presence of toxins is believed to be a major factor in the development of uremia in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Uremic toxins have been divided into 3 groups: small substances dissolved in water, medium molecules: peptides and low molecular weight proteins, and protein-bound toxins. One of the earliest known toxins is urea, the concentration of which was considered negligible in CKD patients. However, subsequent studies have shown that it can lead to increased production of reactive oxygen species (ROS), and induce insulin resistance in vitro and in vivo, as well as cause carbamylation of proteins, peptides, and amino acids. Other uremic toxins and their participation in the damage caused by oxidative stress to biological material are also presented. Macromolecules and molecules modified as a result of carbamylation, oxidative stress, and their adducts with uremic toxins, may lead to cardiovascular diseases, and increased risk of mortality in patients with CKD.