Monocyte gene expression and coronary artery disease

Long-Term Abnormalities of Lipid Profile After a Single Episode of Sepsis

Background: Acute disturbances of the lipid profile are commonplace during acute sepsis episode. However, their long-term persistence has not to be investigated despite pivotal role of dyslipidemia in several comorbidities excessively noted in sepsis survivors (stroke, cardiomyopathy).

Methods: A total of 9,861 individuals hospitalized for a singular episode of sepsis between 2009 and 2019 were identified from electronic medical records. Lab measurements of total cholesterol (Tchol), high-density lipoprotein (HDL-c), low-density lipoprotein (LDL-c), very low-density lipoprotein (VLDL), triglycerides (TG), lipoprotein(a) [Lp (a)], apolipoprotein B (ApoB), and C-reactive protein (CRP). The data were examined as baseline values before sepsis, during hospitalization, and <3 months, 3–6 months, 6–12 months, 1–2 years, and more than 2 years from initial sepsis.

Results: Significant reductions in HDL-c (HDL_baseline = 44.06 vs. HDL_sepsis = 28.2; U = −37.79, p < 0.0001, Cohen's d = 0.22) and LDL-c serum levels were observed during and up to three months post sepsis, with females much less affected. In contrast, male subjects had derangement in HDL present for up to two years after a singular septic episode. Total cholesterol levels were slightly yet significantly elevated for up to two years after sepsis. TG were elevated up to one year [TG_baseline = 128.26 vs. TG_sepsis = 170.27, t(8255) = −21.33, p < 0.0001, Cohen's d = 0.49] and normalized. Lp(a) was elevated up to two years after initial episode [Lp(a)_baseline = 24.6 ± 16.06; Lp(a)_{sepsis−2year} = 8.25 ± 5.17; Lp(a)_{morethan2years} = 61.4 ± 40.1; ANOVA F_{(2, 24)} = 7.39; p = 0.0032]. Response to statin therapy was blunted in sepsis survivors for several years after sepsis resolution. Significant drop-out in prescription of statins and niacin after sepsis was observed. Serum high sensitivity C-reactive protein was elevated for up to five years after sepsis resolution (H [6;1685] = 502.2; p < 0.0001).

Discussion: Lipid abnormalities persisted long after the initial septic insult suggesting potential role in accelerating atherosclerosis and other abnormalities. In addition, sepsis seems to blunt statin effectiveness. Additionally, a significant and unexplained drop in statin use was seen in post-septic period.

Conclusions: Our study suggests that persistent derangements of lipid profile components for up to two years after sepsis may be associated with altered risk of atherosclerosis-related events among sepsis survivors.

Evidence of association of circulating epigenetic-sensitive biomarkers with suspected coronary heart disease evaluated by Cardiac Computed Tomography

Circulating biomarkers available in clinical practice do not allow to stratify patients with coronary heart disease (CHD) prior the onset of a clinically relevant event. We evaluated the methylation status of specific genomic segments and gene expression in peripheral blood of patients undergoing Cardiac Computed Tomography (CCT) for CHD (n = 95).

We choose to investigate cholesterol metabolism. Methylation and gene expression of low density lipoprotein receptor (LDLR), sterol regulatory element-binding factor 2 (SREBF2) and ATP-binding cassette transporter 1 (ABCA1) were evaluated by qRT-PCR. Calcium score (CACS), stenosis degree, total plaque volume (TPV), calcified plaque volume (CPV), non-calcified plaque volume (NCPV) and plaque burden (PB) were assessed in all CHD patients (n = 65). The percentage of methylation at the specific analyzed segment of LDLR promoter was higher in CHD patients vs healthy subjects (HS) (n = 30) (p = 0.001). LDLR, SREBF2 and ABCA1 mRNAs were up-regulated in CHD patients vs HS (p = 0.02; p = 0.019; p = 0.008). SREBF2 was overexpressed in patients with coronary stenosis ≥50% vs subjects with stenosis <50% (p = 0.036). After adjustment for risk factors and clinical features, ABCA1 (p = 0.005) and SREBF2 (p = 0.010) gene expression were identified as independent predictors of CHD and severity. ROC curve analysis revealed a good performance of ABCA1 on predicting CHD (AUC = 0.768; p<0.001) and of SREBF2 for the prediction of disease severity (AUC = 0.815; p<0.001). Moreover, adjusted multivariate analysis demonstrated SREBF2 as independent predictor of CPV, NCPV and TPV (p = 0.022; p = 0.002 and p = 0.006) and ABCA1 as independent predictor of NCPV and TPV (p = 0.002 and p = 0.013).

CHD presence and characteristics are related to selected circulating transcriptional and epigenetic-sensitive biomarkers linked to cholesterol pathway. More extensive analysis of CHD phenotypes and circulating biomarkers might improve and personalize cardiovascular risk stratification in the clinical settings.

Elevated monocyte-specific type I interferon signalling correlates positively with cardiac healing in myocardial infarct patients but interferon alpha application deteriorates myocardial healing in rats

Monocytes are involved in adverse left ventricular (LV) remodelling following myocardial infarction (MI). To provide therapeutic opportunities we aimed to identify gene transcripts in monocytes that relate to post-MI healing and evaluated intervention with the observed gene activity in a rat MI model. In 51 MI patients treated by primary percutaneous coronary intervention (PCI), the change in LV end-diastolic volume index (EDVi) from baseline to 4-month follow-up was assessed using cardiovascular magnetic resonance imaging (CMR). Circulating monocytes were collected at day 5 (Arterioscler Thromb Vasc Biol 35:1066-1070, 2015; Cell Stem Cell 16:477-487, 2015; Curr Med Chem 13:1877-1893, 2006) after primary PCI for transcriptome analysis. Transcriptional profiling and pathway analysis revealed that patients with a decreased LV EDVi showed an induction of type I interferon (IFN) signalling (type I IFN pathway: P value < 0.001; false discovery rate < 0.001). We subsequently administered 15,000 Units of IFN-α subcutaneously in a rat MI model for three consecutive days following MI. Cardiac function was measured using echocardiography and infarct size/cardiac inflammation using (immuno)-histochemical analysis. We found that IFN-α application deteriorated ventricular dilatation and increased infarct size at day 28 post-MI. Moreover, IFN-α changed the peripheral monocyte subset distribution towards the pro-inflammatory monocyte subset whereas in the myocardium, the presence of the alternative macrophage subset was increased at day 3 post-MI. Our findings suggest that induction of type I IFN signalling in human monocytes coincides with adverse LV remodelling. In rats, however, IFN-α administration deteriorated post-MI healing. These findings underscore important but also contradictory roles for the type I IFN response during cardiac healing following MI.

Blood monocyte transcriptome and epigenome analyses reveal loci associated with human atherosclerosis

Little is known regarding the epigenetic basis of atherosclerosis. Here we present the CD14+ blood monocyte transcriptome and epigenome signatures associated with human atherosclerosis. The transcriptome signature includes transcription coactivator, ARID5B, which is known to form a chromatin derepressor complex with a histone H3K9Me2-specific demethylase and promote adipogenesis and smooth muscle development. ARID5B CpG (cg25953130) methylation is inversely associated with both ARID5B expression and atherosclerosis, consistent with this CpG residing in an ARID5B enhancer region, based on chromatin capture and histone marks data. Mediation analysis supports assumptions that ARID5B expression mediates effects of cg25953130 methylation and several cardiovascular disease risk factors on atherosclerotic burden. In lipopolysaccharide-stimulated human THP1 monocytes, ARID5B knockdown reduced expression of genes involved in atherosclerosis-related inflammatory and lipid metabolism pathways, and inhibited cell migration and phagocytosis. These data suggest that ARID5B expression, possibly regulated by an epigenetically controlled enhancer, promotes atherosclerosis by dysregulating immunometabolism towards a chronic inflammatory phenotype.The molecular mechanisms mediating the impact of environmental factors in atherosclerosis are unclear. Here, the authors examine CD14+ blood monocyte's transcriptome and epigenome signatures to find differential methylation and expression of ARID5B to be associated with human atherosclerosis.

Association between rs1761667 polymorphism of CD36 gene and risk of coronary atherosclerosis in Egyptian population

BACKGROUND

Recent studies have demonstrated that CD36 is involved in the progression of atherosclerosis. Associations between rs1761667 polymorphisms of the CD36 gene and susceptibility to coronary artery disease (CAD) are not obvious.

METHODS

We studied the relationship between single nucleotide polymorphisms (SNPs), rs1761667 of CD36 gene and the risk of coronary atherosclerosis in a case-control study composed of 71 CAD patients and 76 healthy controls by assessment of allele frequencies and genotype distributions using real-time polymerase chain reaction (PCR) and the allele discrimination technique. Additionally, we detected CD36 expression by flow cytometry.

RESULTS

The distribution of rs1761667 genotypes between the two groups was significantly different (P<0.001), with the frequency of the AG genotype being significantly higher in the CAD group than in the control group (P<0.001). The expression level of CD36 in the CAD group was significantly higher than that in the control group (P<0.001), with significant differences in the CAD patients with an AG genotype compared with those with an AA and GG genotype (P<0.001). The plasma levels (mg/dL) of low-density lipoprotein (LDL) in the CAD group were much higher than that in the control group (P<0.001). On the other hand, the plasma LDL levels in CAD patients with the AG genotype were remarkably higher than those with the GG and AA genotypes (P=0.046) and AG genotype was significantly more prevalent among type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) patients (P<0.05). After adjusted logistic regression analysis, the AG genotype of rs1761667 was associated with an increased risk of CAD (OR=17.97, 95% CI, 3.19-87.85, P=0.001).

CONCLUSIONS

The AG genotype of the rs1761667 polymorphism in the CD36 gene may be involved in CAD pathogenesis as well as increased body mass index (BMI), T2DM and MetS in the Sohag population of Egypt.

Associations between CD36 gene polymorphisms and susceptibility to coronary artery heart disease

Associations between polymorphisms of the CD36 gene and susceptibility to coronary artery heart disease (CHD) are not clear. We assessed allele frequencies and genotype distributions of CD36 gene polymorphisms in 112 CHD patients and 129 control patients using semi-quantitative polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. Additionally, we detected CD36 mRNA expression by real-time quantitative PCR, and we quantified plasma levels of oxidized low-density lipoprotein (ox-LDL) using an enzyme-linked immunosorbent assay (ELISA). There were no significant differences between the two groups (P>0.05) in allele frequencies of rs1761667 or in genotype distribution and allele frequencies of rs3173798. The genotype distribution of rs1761667 significantly differed between CHD patients and controls (P=0.034), with a significantly higher frequency of the AG genotype in the CHD group compared to the control group (P=0.011). The plasma levels of ox-LDL in patients with the AG genotype were remarkably higher than those with the GG and AA genotypes (P=0.010). In a randomized sample taken from patients in the two groups, the CD36 mRNA expression of the CHD patients was higher than that of the controls. In CHD patients, the CD36 mRNA expression in AG genotype patients was remarkably higher than in those with an AA genotype (P=0.005). After adjusted logistic regression analysis, the AG genotype of rs1761667 was associated with an increased risk of CHD (OR=2.337, 95% CI=1.336-4.087, P=0.003). In conclusion, the rs1761667 polymorphism may be closely associated with developing CHD in the Chongqing Han population of China, and an AG genotype may be a genetic susceptibility factor for CHD.

Cloning and expression of an anti-LDL(-) single-chain variable fragment, and its inhibitory effect on experimental atherosclerosis

The in vivo modified forms of low-density lipoprotein (LDL) are important for the formation of foam cells and as mediators of the immuno-inflammatory process involved in the progression of atherosclerosis. Electronegative LDL, LDL(-), is a LDL subfraction with pro-inflammatory properties that is present in human blood. To investigate possible atheroprotective effects, an anti-LDL(-) single-chain variable fragment (scFv) was expressed in the methylotrophic yeast Pichia pastoris and its activity was evaluated in vitro against macrophages and in experimental atherosclerosis in Ldlr(-/-) mice. The recombinant 2C7 scFv was produced in a yield of 9.5 mg of protein/L. The specificity and affinity of purified 2C7 scFv against LDL(-) was confirmed by ELISA. To assess the activity of 2C7 scFv on foam cell formation, RAW 264.7 macrophages were exposed to LDL(-) in the presence or absence of 2C7 scFv. The 2C7 scFv inhibited the uptake of LDL(-) by macrophages in a dose-dependent manner, and internalization of LDL(-) by these cells was found to be mediated by the CD36 and CD14 receptor. In addition, compared with untreated cells, lipid accumulation in macrophages was decreased, and the expression of Cd36, Tlr-4 and Cox-2 was downregulated in macrophages treated with 2C7 scFv. Importantly, compared with untreated mice, the treatment of Ldlr(-/-) mice with 2C7 scFv decreased the atherosclerotic lesion area at the aortic sinus. In conclusion, our data show that 2C7 scFv inhibits foam cell formation and atherosclerotic plaque development by modulating the expression of genes relevant to atherogenesis. These results encourage further use of this antibody fragment in the development of new therapeutic strategies that neutralize the pro-atherogenic effects of LDL(-).