Andrea Baragetti

High density lipoprotein cholesterol levels are an independent predictor of the progression of chronic kidney disease

Patients with chronic kidney disease (CKD) often present with reduced plasma HDL cholesterol (HDL‐C) levels. Whether this reduction in an epiphenomenon or is involved in disease progression is unclear. The aim of this study was to investigate the relation between HDL‐C levels/function and CKD progression in patients with different degrees of disease.

Progression of carotid vascular damage and cardiovascular events in non-alcoholic fatty liver disease patients compared to the general population during 10 years of follow-up

BACKGROUND AND AIM Non-alcoholic fatty liver disease (NAFLD) is associated not only with liver related morbidity and mortality but also with an increased risk of cardiovascular disease. AIM to evaluate in patients with NAFLD and in matched Controls after 10 years of follow-up 1 the incidence of major cardiovascular and cerebral events 2 the progression of vascular damage. METHODS Clinical and cardio-metabolic data were collected in 125 NAFLD patients and 250 age and gender matched Controls at baseline and 10 years later. Incidence of cardiovascular and cerebral events was recorded. By ultrasonography, carotid intima-media thickness (cIMT), presence of plaques and presence of fatty liver were evaluated. RESULTS 25% of the overall series was lost to follow-up. Sixty-eight (37%) Controls developed steatosis. Major cardiovascular events were observed in thirty-five subjects (17/91 (19%) NAFLD and 18/182 (10%) Controls), with an estimated cumulative risk significantly higher in NAFLD than in Controls, log-rank test for equality of failure functions p = 0.007. At multivariate analysis, presence of plaques (hazard ratio 5.08 (95% C.I. 2.56-10.96) and of steatosis (hazard ratio 1.99 (1.01-3.94)) were the strongest predictors for cardiovascular events. Grade of steatosis, ALT and GGT levels were higher in NAFLD patients who developed cardiovascular events. cIMT value after 10 years was significantly higher in NAFLD than in Controls, but the mean progression rate was higher in Controls (0.015 and 0.006 mm/year, p = 0.001). In conclusion our results suggest that NAFLD has to be included among risk factors for cardiovascular damage and underline the utility to evaluate, once NAFLD is diagnosed, the presence of atherosclerotic lesions.

Telomere shortening over 6 years is associated with increased subclinical carotid vascular damage and worse cardiovascular prognosis in the general population

Leucocyte telomere length (LTL) is an important determinant of telomere function and cellular replicative capacity. The aim of the present study was to examine prospectively the associations between telomere shortening (TS) and both the progression of atherosclerosis and the incidence of cardiovascular events (CVEs).

Obesity-induced metabolic stress leads to biased effector memory CD4+ T cell differentiation via PI3K p110δ/Akt-mediated signals

Summary Low-grade systemic inflammation associated to obesity leads to cardiovascular complications, caused partly by infiltration of adipose and vascular tissue by effector T cells. The signals leading to T cell differentiation and tissue infiltration during obesity are poorly understood. We tested whether saturated fatty acid-induced metabolic stress affects differentiation and trafficking patterns of CD4+ T cells. Memory CD4+ T cells primed in high-fat diet-fed donors preferentially migrated to non-lymphoid, inflammatory sites, independent of the metabolic status of the hosts. This was due to biased CD4+ T cell differentiation into CD44hi-CCR7lo-CD62Llo-CXCR3+-LFA1+ effector memory-like T cells upon priming in high-fat diet-fed animals. Similar phenotype was observed in obese subjects in a cohort of free-living people. This developmental bias was independent of any crosstalk between CD4+ T cells and dendritic cells and was mediated via direct exposure of CD4+ T cells to palmitate, leading to increased activation of a PI3K p110δ-Akt-dependent pathway upon priming.

Pentraxin 3 (PTX3) plasma levels and carotid intima media thickness progression in the general population.

BACKGROUND AND AIM Pentraxin 3 (PTX3) is an essential component of the humoral arm of innate immunity and, like C-reactive protein, is independently associated with the risk of developing vascular events. Aim of this study was to investigate, in two large population-based surveys, the Bruneck Study and the PLIC Study, whether PTX3 plasma levels predict the progression of common carotid artery intima-media thickness (CCA-IMT), a surrogate marker of atherosclerosis, in the general population during 5 or 6 years of follow-up. RESULTS In the Bruneck Study, PTX3 plasma levels did not predict a faster progression of CCA-IMT either in the carotid artery or in the femoral artery. This finding was confirmed in the PLIC Study where subjects within the highest tertile of PTX3 did not show an increased progression of CCA-IMT. PTX3 plasma levels were also not associated with the fastest maximum IMT progression. In summary, in more than 2400 subjects from the general population, PTX3 plasma level is neither an independent predictor of progression of subclinical atherosclerosis in different arterial territories, including carotid and femoral arteries nor of incident cardiovascular events. CONCLUSION These findings support the relevance of investigating the predictive value of PTX3 plasma levels only in specific settings, like overt CVD, heart failure or acute myocardial infarction.

Regulatory T Cell Migration Is Dependent on Glucokinase-Mediated Glycolysis

SUMMARY Migration of activated regulatory T (Treg) cells to inflamed tissue is crucial for their immune‐modulatory function. While metabolic reprogramming during Treg cell differentiation has been extensively studied, the bioenergetics of Treg cell trafficking remains undefined. We have investigated the metabolic demands of migrating Treg cells in vitro and in vivo. We show that glycolysis was instrumental for their migration and was initiated by pro‐migratory stimuli via a PI3K‐mTORC2‐mediated pathway culminating in induction of the enzyme glucokinase (GCK). Subsequently, GCK promoted cytoskeletal rearrangements by associating with actin. Treg cells lacking this pathway were functionally suppressive but failed to migrate to skin allografts and inhibit rejection. Similarly, human carriers of a loss‐of‐function GCK regulatory protein gene—leading to increased GCK activity—had reduced numbers of circulating Treg cells. These cells displayed enhanced migratory activity but similar suppressive function, while conventional T cells were unaffected. Thus, GCK‐dependent glycolysis regulates Treg cell migration. HIGHLIGHTSMigration of regulatory T (Treg) cells requires glycolysisThis is mediated by the enzyme glucokinase induced by a PI3K‐mTORC2 pathwayTreg cells lacking this pathway are unable to localize to inflammatory sitesA loss‐of‐function GCK regulator gene causes enhanced motility of human Treg cells Regulatory T cell localization to inflammatory sites is key to their homeostatic function. Kishore and colleagues demonstrate that Treg cell migration requires the activation of glycolysis by the enzyme glucokinase induced via a Treg cell‐selective PI3K‐mTORC2 pathway.

Subclinical atherosclerosis is associated with Epicardial Fat Thickness and hepatic steatosis in the general population.

BACKGROUND AND AIMS Abdominal obesity and hepatic steatosis are ectopic fat depots associated with Metabolic Syndrome (MetS). Epicardial Fat Thickness (EFT) is a newly discovered one, increasing with obesity, insulin resistance and MetS. Therefore we studied whether different ectopic fat markers, and EFT in particular, are associated with MetS and markers of subclinical cardiovascular disease. METHODS AND RESULTS 868 subjects from the PLIC Study were included, EFT, aortic calcifications, carotid Intima-Media Thickness (c-IMT) and echocardiographic parameters were determined by ultrasound; extra-cardiac atherosclerotic lesions were defined in presence of plaques at both carotid and aortic levels. Hepatic steatosis degrees were defined according to a scoring system. Abdominal adiposity was determined using Dual X-ray Absorbimetry (DEXA). Independently from age, women showed higher EFT versus men (4.5 (0.20-9.00) mm vs 4.00 (0.10-8.00) mm, p = 0.013); EFT was thicker in post-menopausal women (independently from hormone-replacement therapy). EFT, liver steatosis and abdominal adiposity increased with MetS (p < 0.001). EFT was the only ectopic fat marker associated with cardiac dysfunction (OR = 1.340 [1.088-1.651 95% C.I., p = 0.006); liver steatosis and EFT were associated with extra-cardiac plaques (OR = 2.529 [1.328-4.819] 95% C.I., p < 0.001 and OR = 1.195 [1.008-1.299] 95% C.I., p = 0.042; respectively). On top of cardiovascular risk factors, only EFT improved the discrimination of subjects with cardiac dysfunction and atherosclerotic plaques. CONCLUSIONS EFT is associated with left ventricular dysfunction and subclinical atherosclerosis. Our data suggest that EFT may represent an additional tool for the stratification of cardiovascular risk.

PCSK9 deficiency results in increased ectopic fat accumulation in experimental models and in humans

Background Proprotein convertase subtilisin kexin type 9 (PCSK9) regulates low-density lipoprotein and very low-density lipoprotein receptor expression in several tissues. Here we evaluated whether PCSK9 may modulate the handling of triglycerides in the liver and peripheral tissues. Methods Subjects from the PLIC cohort were genotyped for the loss-of-function PCSK9 R46L variant and characterized for clinical and biochemical parameters, total and android fat mass, hepatic steatosis and epicardial fat thickness. Visceral adipose tissue and subcutaneous adipose tissue in PCSK9 KO and wild type mice were quantified by nuclear magnetic resonance imaging. Results Carriers of the R46L variant (n = 13) had lower low-density lipoprotein cholesterol levels, higher body mass index and increased percentage of total and android fat masses compared with non-carriers (n = 521). R46L variant associated with a two-fold increase prevalence of hepatic steatosis and higher epicardial fat thickness. These observations were replicated in PCSK9 KO mice, which showed increased visceral adipose tissue (but not subcutaneous adipose tissue) when fed chow or high-fat diet for 20 weeks, compared with wild type mice. Conclusions These data suggest that genetically determined PCSK9 deficiency might be associated with ectopic fat accumulation.

Statins decrease thrombin generation in patients with hypercholesterolemia

OBJECTIVE Statins are cholesterol-lowering agents with antithrombotic effect possibly unrelated to their lipid-lowering properties. Traditional global coagulation tests failed, however, to reveal clinically relevant change after treatment. We therefore sought to investigate whether statins were able to modify thrombin generation in hypercholesterolemia. METHODS Fifty-one patients who needed treatment with statins were enrolled in this study. Thrombin generation, assessed as endogenous thrombin potential (the amount of thrombin generated after triggering coagulation with small amount of tissue factor) was measured at pre- and two months post-treatment with statins. RESULTS The median (inter-quartile range) level of total cholesterol that was 325 mg/dL (278-405) decreased significantly [211 mg/dL (197-247)] at post-treatment (p<0.001); the median level of HDL cholesterol that was 49 mg/dL (43-56) increased significantly [55 mg/dL (47-66)] at post-treatment (p<0.001). The median endogenous thrombin potential (inter-quartile range) before treatment was 2372 nM·min (2008-2617) and decreased to 2,048 nM·min (1764-2375) (p<0.001) after treatment. CONCLUSION The results support the hypothesis of a direct link between statins and coagulation through their capacity to lower thrombin generation in patients with hypercholesterolemia. PRACTICE IMPLICATIONS The antithrombotic properties of statins could be mediated (at least in part) by their endogenous thrombin potential lowering effect. This interesting hypothesis warrants evaluation by clinical trials.

miR-30c-5p regulates macrophage-mediated inflammation and pro-atherosclerosis pathways

Aims Atherosclerosis is an inflammatory disease wherein cholesterol-loaded macrophages play a major role. MicroRNAs and microparticles propagate inflammatory pathways and are involved in cardiovascular disease. We aimed to screen and validate circulating microRNAs correlated with atherosclerosis development in humans, and to dissect the molecular mechanisms associated with atherogenesis using in vitro and in vivo approaches. Methods and results A panel of 179 secreted microRNAs was screened in plasma samples of patients with and without atherosclerosis, and validated cross-sectionally and prospectively in patients followed for up to 11 years. miR-30c-5p was inversely correlated with total and LDL cholesterol, carotid intimal media thickness (CIMT), presence and future development of plaques. Using a human macrophage line and in vitro gene silencing strategies, we found that miR-30c-5p was downregulated by oxidized LDL (oxLDL) via the scavenger receptor CD36 and inhibition miR processing by Dicer. In turn, miR-30c-5p downregulation was responsible for the effects of oxLDL on macrophage IL-1β release, caspase-3 expression, and apoptosis. miR-30c-5p loaded into microparticles was uptaken by macrophages and regulated target genes, like caspase-3, at transcriptional level. To establish the relevance of this pathway on endothelial damage as the earliest step of atherogenesis, we show that systemic miR-30c-5p knockdown induced caspase-3 and impaired endothelial healing after carotid injury in C57Bl/6 J mice. Conclusions With an unbiased screening of secreted microRNAs, we identify reduction of miR-30c-5p in microparticles as a promoter of early atherosclerosis, by conveying pro-inflammatory pro-apoptotic signals and impairing endothelial healing. Therefore, stimulation of miR-30c-5p is a candidate direct anti-atherosclerotic therapy.