Marta Novo

Gut‐Derived Serum Lipopolysaccharide is Associated With Enhanced Risk of Major Adverse Cardiovascular Events in Atrial Fibrillation: Effect of Adherence to Mediterranean Diet

Background Gut microbiota is emerging as a novel risk factor for atherothrombosis, but the predictive role of gut‐derived lipopolysaccharide (LPS) is unknown. We analyzed (1) the association between LPS and major adverse cardiovascular events (MACE) in atrial fibrillation (AF) and (2) its relationship with adherence to a Mediterranean diet (Med‐diet). Methods and Results This was a prospective single‐center study including 912 AF patients treated with vitamin K antagonists (3716 patient‐years). The primary end point was a composite of MACE. Baseline serum LPS, adherence to Med‐diet (n=704), and urinary excretion of 11‐dehydro‐thromboxane B2 (TxB2, n=852) were investigated. Mean age was 73.5 years; 42.9% were women. A total of 187 MACE (5.0% per year) occurred: 54, 59, and 74 in the first, second, and third tertile of LPS, respectively (log‐rank test P=0.004). Log‐LPS (hazard ratio 1.194, P=0.009), age (hazard ratio 1.083, P<0.001), and previous cerebrovascular (hazard ratio 1.634, P=0.004) and cardiac events (hazard ratio 1.822, P<0.001) were predictors of MACE. In the whole cohort, AF (versus sinus rhythm) (β 0.087, P=0.014) and low‐density lipoprotein cholesterol (β 0.069, P=0.049) were associated with circulating LPS. Furthermore, Med‐diet score (β −0.137, P<0.001) was predictive of log‐LPS, with fruits (β −0.083, P=0.030) and legumes (β −0.120, P=0.002) negatively associated with log‐LPS levels. Log‐LPS and log‐TxB2 were highly correlated (r=0.598, P<0.001). Log‐LPS (β 0.574, P<0.001) and Med‐diet score (β −0.218, P<0.001) were significantly associated with baseline urinary excretion of TxB2. Conclusions In this cohort of AF patients, LPS levels were predictive of MACE and negatively affected by high adherence to Med‐diet. LPS may contribute to MACE incidence in AF by increasing platelet activation.

Gut-derived endotoxin stimulates factor VIII secretion from endothelial cells. Implications for hypercoagulability in cirrhosis

BACKGROUND & AIMS Patients with cirrhosis display enhanced blood levels of factor VIII, which may result in harmful activation of the clotting system; however, the underlying mechanism is unknown. METHODS We performed a cross-sectional study in patients with cirrhosis (n=61) and matched controls (n=61) comparing blood levels of factor VIII, von Willebrand factor (vWf), lipopolysaccharide (LPS) and positivity for Escherichia coli DNA. Furthermore, we performed an in vitro study to investigate if LPS, in a concentration range similar to that found in the peripheral circulation of cirrhotic patients, was able to elicit factor VIII secretion from human umbilical vein endothelial cells (HUVEC). RESULTS Patients with cirrhosis displayed higher serum levels of LPS (55.8 [42.2-79.9] vs. 23.0 [7.0-34.0]pg/ml, p<0.001), factor VIII (172.0 [130.0-278.0] vs. 39.0 [26.0-47.0]U/dl, p<0.0001), vWf (265.0 [185.0-366.0] vs. 57.0 [48.0-65.0]U/dl, p<0.001) and positivity for Escherichia coli DNA (88% vs. 3%, p<0.001, n=34) compared to controls. Serum LPS correlated significantly with factor VIII (r=0.80, p<0.001) and vWf (r=0.63, p<0.001). Only LPS (beta-coefficient=0.70, p<0.0001) independently predicted factor VIII levels. The in vitro study showed that LPS provoked factor VIII and vWf release from HUVEC via formation and secretion of Weibel-Palade bodies, a phenomenon blunted by pre-treating HUVEC with an inhibitor of Toll-like receptor 4. CONCLUSIONS The study provides the first evidence that LPS derived from gut microbiota increases the systemic levels of factor VIII via stimulating its release by endothelial cells. Lay summary: Cirrhosis is associated with thrombosis in portal and systemic circulation. Enhanced levels of factor VIII have been suggested to play a role but the underlying mechanism is still unclear. Here we show that patients with cirrhosis display a concomitant increase of factor VIII and lipopolysaccharide (LPS) from Escherichia coli and suggest that LPS contributes to the release of factor VIII from endothelial cells.

Incidence of bleeding in patients with atrial fibrillation and advanced liver fibrosis on treatment with vitamin K or non-vitamin K antagonist oral anticoagulants

OBJECTIVES To investigate the incidence of bleeding events in atrial fibrillation (AF) patients treated with vitamin K (VKAs) or non-vitamin K antagonist oral anticoagulants (NOACs) screened for the presence of liver fibrosis (LF). BACKGROUND Previous studies provided conflicting results on bleeding risk in AF patients with liver disease on VKAs, and no data on NOACs in this setting are available. METHODS Post-hoc analysis of a prospective, observational multicentre study including 2330 AF outpatients treated with VKAs (n = 1297) or NOACs (n = 1033). Liver damage was quantified by the FIB-4 score (>3.25), a validated marker of LF. The primary endpoint was the incidence of any bleeding, according to ISTH classification. RESULTS A high FIB-4 was present in 129 (5.5%) patients: 77 (5.9%) on VKA and 52 (5.0%) on NOACs (p = 0.344). During follow-up, 357 (15.3%) patients experienced a bleeding: 261 (80 major and 180 minor) with VKAs (7.2%/year), and 96 (40 major and 56 minor) with NOACs (6.4%/year). In VKA-treated patients, but not in those on NOACs, FIB-4 >3.25 was associated with higher major bleeding (14.3% vs. 5.6%, log-rank test p < 0.001). Multivariable Cox regression model showed that FIB-4 was associated with major bleeding only in VKA-treated patients (HR: 3.075, 95% CI 1.626-5.818, p = 0.001). On multivariable analysis, FIB-4 was not significantly associated with CVEs neither in VKA or NOAC-treated patients. CONCLUSION We found a significant association between LF and major bleedings in AF patients treated with VKA, which was not evident in patients on NOACs.

Oleuropein, a component of extra virgin olive oil, lowers postprandial glycaemia in healthy subjects

Extra virgin olive oil lowers postprandial glycaemia. We investigated if oleuropein, a component of extra virgin olive oil, exerts a similar effect on postprandial glycaemia and the underlying mechanism.

Glucocorticoids impair platelet thromboxane biosynthesis in community-acquired pneumonia

Graphical abstract Figure. No caption available. ABSTRACT Previous reports suggest that community‐acquired pneumonia (CAP) is associated with an enhanced risk of myocardial infarction (MI) and that enhanced platelet activation may play a role. Aims of this study were to investigate if urinary excretion of 11‐dehydro‐thromboxane (Tx) B2, a reliable marker of platelet activation in vivo, was elevated in CAP and whether glucocorticoid administration reduced platelet activation. Three‐hundred patients hospitalized for CAP were recruited and followed‐up until discharge. Within the first 2 days from admission, urinary 11‐dehydro‐TxB2 and serum levels of methylprednisolone and betamethasone were measured. 11‐Dehydro‐TxB2 was also measured in a control group of 150 outpatients, matched for age, sex, and comorbidities. Finally, in‐vitro studies were performed to assess if glucocorticoids affected platelet activation, at the same range of concentration found in the peripheral circulation of CAP patients treated with glucocorticoids. Compared to controls, CAP patients showed significantly higher levels of 11‐dehydro‐TxB2 (110 [69–151] vs. 163 [130–225] pg/mg creatinine; p < 0.001). During the in‐hospital stay, 31 patients experienced MI (10%). A COX regression analysis showed that 11‐dehydro‐TxB2 independently predicted MI (p = .005). CAP patients treated with glucocorticoids showed significantly lower levels of 11‐dehydro‐TxB2 compared to untreated ones (147 [120–201] vs. 176 [143–250] pg/mg creatinine; p < 0.001). In vitro, glucocorticoids‐treated platelets showed a dose‐dependent decrease of ADP‐induced platelet aggregation, TxB2 production, cPLA2 phosphorylation and arachidonic acid release from the platelet membrane. In conclusion, platelet TxB2 is overproduced in CAP patients and may be implicated in MI occurrence. Glucocorticoids reduce platelet release of TxB2 in vitro and urinary excretion of 11‐dehydro‐TxB2 in vivo and may be a novel tool to decrease platelet activation in this setting.

Remnant Lipoprotein Cholesterol and Cardiovascular and Cerebrovascular Events in Patients with Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is characterized by an atherogenic dyslipidaemia and an increased cardiovascular risk. Remnant lipoprotein cholesterol (RLP-C) is emerging as a novel cardiovascular risk factor, but its predictive value in patients with NAFLD is unknown. We investigated factors affecting RLP-C levels, and the association with major adverse cardiovascular and cerebrovascular events (MACCE) in NAFLD. A prospective observational cohort study was carried out including 798 unselected patients with cardio-metabolic diseases screened by ultrasound for the presence of NAFLD. Fasting RLP-C (mg/dL) was calculated as total cholesterol—(HDL (high-density lipoprotein) + LDL (low-density-lipoprotein)). Primary endpoint of the follow-up study was a combined endpoint of MACCE. Patients with NAFLD (79.2%) had higher median fasting RLP-C in comparison to those without (27.0 vs. 20.0 mg/dL, respectively p < 0.001). Metabolic syndrome, NAFLD, age above median, and female sex were independently associated to fasting RLP-C above the median. In patients with NAFLD, values of RLP-C were associated with liver disease severity, as shown by the increasing value of RLP-C across tertiles of aspartate aminotransferase (AST) (p = 0.002) and gamma-glutamyl transpeptidase (GGT) (p < 0.001). Furthermore, levels of RLP-C and Hamaguchi score, were significantly correlated (r = 0.193, p < 0.001). During a median follow-up of 32 months (interquartile range: 14.2–51.7, 1700 person-years), 41 MACCE (2.41%/year) were registered in 596 NAFLD patients. The rate of events was higher in NAFLD patients with RLP-C above the median compared to those below (log-rank test p = 0.040). Age (hazard ratio (HR) 1.039, 95% confidence interval (CI), 1.005–1.074, p = 0.024), previous cardiovascular events (HR 2.210, 95% CI, 1.052–4.643, p = 0.036), female sex (HR 0.454, 95% CI, 0.208–0.989, p = 0.047) and RLP-C above the median (HR 2.202, 95% CI, 1.132–4.285, p = 0.020) were associated with MACCE. In conclusion, we found that NAFLD was independently associated with higher circulating RLP-C, and that high RLP-C levels were predictive of MACCE in patients with NAFLD.

Blood hydrogen peroxide break-down activity in healthy subjects and in patients at risk of cardiovascular events

BACKGROUND AND AIMS Antioxidant status has been shown to be associated with cardiovascular events (CVEs). The aim of the study was to develop an assay measuring serum hydrogen peroxide (H2O2) break-down activity (HBA) of healthy subjects (HS) and to validate it in a cohort of patients with atrial fibrillation (AF). METHODS We developed the HBA assay in 121 HS and validated it in 842 AF patients. The occurrence of CVEs was registered and correlated with HBA in AF during a median follow-up of 30.6 months (3226 patient-years). A combined endpoint of CVEs included fatal/non-fatal ischemic stroke and myocardial infarction, cardiovascular death and transient ischemic attack. RESULTS In HS, median HBA was 61.2% [IQR: 52.9-69.4]. AF patients disclosed lower HBA than 30 HS balanced for age and sex (48.6% [IQR: 24.7-65.1] vs. 59.4% [IQR: 49.2-66.2], p < 0.001). During a mean follow-up of 30.6 months (3226 patient-years), 168 CVEs occurred (5.2%/year). A multivariable Coxs proportional hazards regression analysis showed that age group 3 (71-80 years, HR:5.419, p = 0.020), age group 4 (>80 years, HR:9.783, p = 0.002), diabetes (HR:1.464, p = 0.049), previous cardiac events (HR:1.887, p = 0.001) and HBA (below median, HR:2.313, p < 0.001) predicted CVEs. CONCLUSIONS We developed an easy assay to measure serum HBA, which was associated with CVEs in AF patients. This assay may represent an additional useful tool for cardiovascular risk stratification and should be validated in other high-risk populations.