Genetic evidence for a causal link between gut microbiota and arterial embolism and thrombosis: a two-sample Mendelian randomization study.

Background: Previous research has hinted at a crucial link between gut microbiota and arterial embolism and thrombosis, yet the causal relationship remains enigmatic. To gain a deeper understanding, we aimed to comprehensively explore the causal relationship and elucidate the impact of the gut microbiota on the risk through a two-sample Mendelian randomization (MR) study. Methods: Genetic instrumental variables for gut microbiota were identified from a genome-wide association study (GWAS) of 18,340 participants. Summary statistics for IBS were drawn from a GWAS including 1,076 cases and 381,997 controls. We used the inverse-variance weighted (IVW) method as the primary analysis. To test the robustness of our results, we further performed the weighted median method, MR-Egger regression, and MR pleiotropy residual sum and outlier test. Results: We identified three bacterial traits that were associated with the risk of arterial embolism and thrombosis: odds ratio (OR): 1.58, 95% confidence interval (CI): 1.08-2.31, p = 0.017 for genus Catenibacterium; OR: 0.64, 95% CI: 0.42-0.96, p = 0.031 for genus Dialister; and OR: 2.08, 95% CI: 1.25-3.47, p = 0.005 for genus Odoribacter. The results of sensitivity analyses for these bacterial traits were consistent (P<0.05). Conclusion: Our systematic analyses provided evidence to support a potential causal relationship between several gut microbiota taxa and the risk of arterial embolism and thrombosis. More studies are required to show how the gut microbiota affects the development of arterial embolism and thrombosis.

[Application of timolol in preventing variceal hemorrhage in patients with portal hypertension].

OBJECTIVE: To determine the effectiveness of timolol in preventing first variceal hemorrhage in portal hypertensive patients with esophageal varices. METHODS: A total of 42 cirrhotic patients with esophageal varices were enrolled in this study and received timolol or band ligation therapy randomly,with 21 patients in each group. The diameters of portal vein (PV), superior mesenteric vein (SMV), and splenic vein (SPV) as well as the portal venous flow and the splenic venous flow were measured. The first esophageal variceal bleeding of the two groups was recorded. RESULTS: The diameters of PV, SMV, and SPV as well as the flow of PV and SPV showed no significant difference before and after treatment in band ligation group (P>0.05). In timolol group,however,the diameter of portal vein significantly decreased after treatment [(14.11±2.96) mm vs. (12.15±1.61)mm, P<0.05], and the average blood flow of portal vein also significantly decreased after treatment [(1277.33±495.19) ml/min vs. (719.17±245.16)ml/min, P<0.05]. Both timolol and band ligation effectively prevented esophageal variceal bleeding, and the risk of first esophageal variceal bleeding in these two groups were not significantly different (15% vs. 10%, P<0.05). CONCLUSIONS: Timolol is safe and effective in preventing the first variceal bleeding in portal hypertensive patients with esophageal varices.

Comparison of the serum metabolic signatures based on 1H NMR between patients and a rat model of deep vein thrombosis.

Deep vein thrombosis (DVT) and pulmonary embolism (PE) have high morbidity, reduce quality of life, and can cause death. Biomarkers or genetic risk factors have not been identified in patients with DVT. In present study, serum of 61 patients suffering from DVT and a rat DVT model (n = 10) were assayed by a proton nuclear magnetic resonance (1H NMR) metabolomics technique combing with multivariate statistical analysis to identify the metabolites. The MetPA platform was used to identify differences in the metabolic pathways between the rat model and patients. The metabolomics results discovered that 11 different metabolites in rats and 20 different metabolites in DVT patients. Seven metabolites both altered in the rats and patients. Moreover, we observed changes in the metabolic pathways, including carbohydrate metabolism, lipid metabolism, and amino acid metabolism that were induced immediately by the thrombosis. Pathway of aminoacyl-tRNA biosynthesis perturbed only in the patients which was associated with the genetic risk factor of DVT. The study demonstrated that serum 1H NMR metabolomics can be used to diagnose DVT in the clinic. The altered pathways related to thrombosis and genetics will provide a foundation and new strategies for understanding the pathological mechanism and pharmacological targets of DVT.

[COX-2 and mPGES-1 expression in carotid atherosclerotic plaques].

OBJECTIVE: To investigate the changes in the expressions of inducible cyclooxygenase type 2 (COX-2) and membrane associated prostaglandin E-1(mPGES-1) in human carotid atherosclerotic plaques and to explore possible mechanisms of inflammatory process involved in plaque stability. METHODS: The mRNA and protein levels of COX-2 and mPGES-1 were compared between minimally and grossly atherosclerotic arterial tissues. COX-2 and mPGES-1 gene expression were established by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) in 10 mesenchymal artery controls and 24 atherosclerotic specimens. Presence of COX-2 and mPGES-1 protein was assessed by Western blotting. RESULTS: Immunohistochemical staining showed that the COX-2 and mPGES-1 immunoreactive substances were present in the cytoplasm of smooth muscle cell. Compared with the control group, immunostaining positive cells increased in carotid atherosclerotic plaque group. COX-2 and mPGES-1 gene expression was significantly elevated in atherosclerotic plaques (P< 0.05, respectively). The increased mRNA and protein levels of COX-2 and mPGES-1 were correlated in atherosclerotic tissue (P< 0.05). The mRNA and protein levels of COX-2 and mPGES-1 related to degree of pathological damage in atherosclerotic tissue (P< 0.05). COX-2 and mPGES-1 were not found in the control group (mesenteric vascular walls). CONCLUSION: COX-2 and mPGES-1 expression in plaques is significantly higher than that in the control group. These findings suggests that COX-2 and mPGES-1 might play a role in pathogenesis of atheroscleros and modulation of inflammatory process involved in plaque stability, and COX-2 may have proinflammatory enzyme properties.

[Histochemical and ultrastructure study of bile cast in liver transplantation patients].

OBJECTIVE: To investigate the histological components and solubility of the bile-cast, and to study the pathological course of bile cast formation. METHODS: HE staining, bilirubin staining (Gmelin reaction), Masson's staining, alcian blue staining and fibrin staining (weigert's) were performed on the formalin-fixed paraffin-embedded section of the bile cast. Ultrastructure was examined under the scanning electron microscope. Solubility test was also conducted using chymotrypsin, heparin, trypsin solution, HCl and NaOH solution to dissolve the bile-cast. RESULTS: The major components of the bile-cast were bilirubin crystals and collagen fibers. Between the mass of collagen fibers there was certain blood vessel structure. Necrosis bile duct structure was not found in the cast. Under the scanning electron microscope, four kinds of crystal morphologies were viewed. There were some mucoid mass and necrosis defluvium epithelial cells in the bile cast. Solubility test showed that the bile cast could be partial dissolved in NaOH solution (pH = 12.5). No dissolution was found in HCl solution (pH = 5.0), chymotrypsin solution, heparin and trypsin solution. CONCLUSIONS: Collagen fibers work as framework in the bile cast with bilirubin crystal filling between the framework. The emergence of fibroblast and blood vessels indicated the formation of bile cast might be the course of exudation and organization due to bile duct epithelium damage. Bile cast could be partially dissolved in alkaline solution, but could not be dissolved in acid solution, or in chymotrypsin, heparin and trypsin solutions.

Acquisition of anoikis resistance through CD147 upregulation: A new mechanism underlying metastasis of hepatocellular carcinoma cells.

Acquisition of anoikis resistance is a prerequisite for the metastasis of hepatocellular carcinoma (HCC) cells. Activation of growth factor signaling pathways and rearrangement of the cytoskeleton have been reported as vital steps in this process. However, key molecules involved in anoikis resistance remain to be determined. The aim of this study was to investigate the effect of CD147 on HCC cells resistant to anoikis. The human SMMC-7221 human HCC cell line was used. Immunofluorescence was used to investigate the expression levels of CD147. Anoikis-induced cell death was assessed using trypan blue exclusion. In the present study, the results showed that SMMC-7721 HCC cells exhibited significant morphological changes when suspended in culture medium supplemented with 1% methocel and a subpopulation of cells resistant to anoikis was acquired with higher viability and invasion ability. CD147 was identified to be significantly increased in cells resistant to anoikis, when compared to the parental cells. CD147 knockdown by siRNA notably induced cell anoikis, partially through the inactivation of PI3K/Akt pathway. All of these evidence provide a novel CD147-related mechanism underlying the metastasis of HCC cells.

[Secretory expression of chimeric Fab antibody HAb18 against human hepatocellular carcinoma in Pichia pastoris].

AIM: To express secretively chimeric Fab antibody HAb18 (cFab) against human hepatocellular carcinoma in Pichia pastoris. METHODS: Genes encoding CL chain and Fd fragment of cFab antibody HAb18 were subcloned into vectors pPIC9K and pPICZalphaA, respectively. After confirmed by DNA sequence analysis, the recombinant plasmids pPIC9K/CL and pPICZalphaA/Fd were transformed into the genome of Pichia pastoris GS115. Mut(+) multiple insert transformants were screened by G418 and Zeocin and then induced with 5 mL/L methanol to express cFab. RESULTS: 4 days after methanol induction, 26 mg/L of the cFab fragment was detected in the culture supernatant. Western blot proved that the expressed protein could specifically bind with HAb18GEF antigen. CONCLUSION: The successful expression of cFab/HAb18 in Pichia pastoris lays the foundation for large-scale production and further application of the antibody.