Background. The relevance of neutrophil extracellular traps (NETs) in acute ST-elevation myocardial infarction (STEMI) is unclear. We explored the temporal profile of circulating NET markers and their associations to myocardial injury and function and to adverse clinical events in STEMI patients. Methods and Results. In 259 patients, blood samples were drawn before and after PCI, on day 1, and after 4 months. Double-stranded deoxyribonucleic acid (dsDNA) and myeloperoxidase-DNA (MPO-DNA) were measured in serum by a nucleic acid stain and ELISA. Cardiac magnetic resonance imaging assessed microvascular obstruction (MVO), area at risk, infarct size, myocardial salvage index, left ventricular ejection fraction (LVEF), and change in indexed left ventricular end-diastolic volume (LVEDVi). Clinical events were registered after 12 months. dsDNA and MPO-DNA levels were highest before PCI, with reduced levels thereafter (all p≤0.02). Patients with high vs. low day 1 dsDNA levels (>median; 366 ng/ml) more frequently had MVO, larger area at risk, larger infarct size acutely and after 4 months, and lower myocardial salvage index (all p<0.03). Moreover, they had lower LVEF acutely and after 4 months, and larger change in LVEDVi (all p≤0.014). High day 1 dsDNA levels also associated with risk of having a large infarct size (>75th percentile) and low LVEF (≤49%) after 4 months when adjusted for gender, time from symptoms to PCI, and infarct localization (OR 2.3 and 3.0, both p<0.021), and patients with high day 1 dsDNA levels were more likely to experience an adverse clinical event, also when adjusting for peak troponin T (hazard ratio 5.1, p=0.012). No such observations were encountered for MPO-DNA. Conclusions. High day 1 dsDNA levels after STEMI were associated with myocardial infarct size, adverse left ventricular remodeling, and clinical outcome. Although the origin of dsDNA could be discussed, these observations indicate a potential role for dsDNA in acute myocardial ischemia. This trial is registered with S-08421d, 2008/10614 (Regional Committee for Medical Research Ethics in South-East Norway (2008)).

Platelet inhibition is important for patients with coronary artery disease. When dual antiplatelet therapy (DAPT) is required, a P2Y12-antagonist is usually recommended in addition to standard aspirin therapy. The most used P2Y12-antagonists are clopidogrel, prasugrel and ticagrelor. Despite DAPT, some patients experience adverse cardiovascular events, and insufficient platelet inhibition has been suggested as a possible cause. In the present review we have performed a literature search on prevalence, mechanisms and clinical implications of resistance to P2Y12 inhibitors. The PubMed database was searched for relevant papers and 11 meta-analyses were included. P2Y12 resistance is measured by stimulating platelets with ADP ex vivo and the most used assays are vasodilator stimulated phosphoprotein (VASP), Multiplate, VerifyNow (VN) and light transmission aggregometry (LTA). The frequency of high platelet reactivity (HPR) during clopidogrel therapy is predicted to be 30%. Genetic polymorphisms and drug-drug interactions are discussed to explain a significant part of this inter-individual variation. HPR during prasugrel and ticagrelor treatment is estimated to be 3–15% and 0–3%, respectively. This lower frequency is explained by less complicated and more efficient generation of the active metabolite compared to clopidogrel. Meta-analyses do show a positive effect of adjusting standard clopidogrel treatment based on platelet function testing. Despite this, personalized therapy is not recommended because no large-scale RCT have shown any clinical benefit. For patients on prasugrel and ticagrelor, platelet function testing is not recommended due to low occurrence of HPR.

Aims: We recently reported five cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) 7–10 days after receiving the first dose of the ChAdOx1 nCoV-19 adenoviral vector vaccine against corona virus disease 2019 (COVID-19). We aimed to investigate the pathogenic immunological responses operating in these patients. Methods and results: We assessed circulating inflammatory markers by immune assays and immune cell phenotyping by flow cytometry analyses and performed immunoprecipitation with anti-platelet factor (PF)4 antibody in plasma samples followed by mass spectrometry from all five patients. A thrombus was retrieved from the sinus sagittal superior of one patient and analysed by immunohistochemistry and flow cytometry. Precipitated immune complexes revealed multiple innate immune pathway triggers for platelet and leucocyte activation. Plasma contained increased levels of innate immune response cytokines and markers of systemic inflammation, extensive degranulation of neutrophils, and tissue and endothelial damage. Blood analyses showed activation of neutrophils and increased levels of circulating H3Cit, dsDNA, and myeloperoxidase–DNA complex. The thrombus had extensive infiltration of neutrophils, formation of neutrophil extracellular traps (NETs), and IgG deposits. Conclusions: The results show that anti-PF4/polyanion IgG-mediated thrombus formation in VITT patients is accompanied by a massive innate immune activation and particularly the fulminant activation of neutrophils including NETosis. These results provide novel data on the immune response in this rare adenoviral vector-induced VITT.

Background: Metabolic syndrome (MetS) is a cluster of conditions that conjoined represents a 1.5–2.5 fold increased risk of developing cardiovascular disease (CVD). Recent studies have reported that gut dysbiosis and leakage of bacterial components, may contribute to the metabolic disturbances and systemic inflammation observed in subjects with MetS. Chronic exposure to lipopolysaccharide (LPS) has been shown to induce features of MetS in experimental studies. LPS interacts with the innate immune system, facilitated through LPS-binding protein (LBP) and the co-receptor CD14, both regarded as markers of gut leakage.Purpose: We investigated whether circulating levels of LBP and sCD14 are associated with the presence of MetS and its components, and further any association with systemic inflammation.Methods: We examined 482 men, aged between 65 and 75 years, all at high CVD risk. MetS criteria’s according to the US National Cholesterol Education Program Adult Treatment Panel III were met in 182 subjects (38%).Results: Levels of LBP and sCD14 did not differ between individuals with and without MetS. However, a trend towards increased risk of MetS through quartiles of LBP was observed (p = 0.05). Individuals in the highest quartile (Q4), had an increased risk of MetS (OR = 1.76, 95% CI (1.04–3.00), compared to the lowest quartile (Q1) (p = 0.04). With regard to the separate constituents of MetS, patients who met the waist circumference criterion had significant higher concentration of LBP compared to those who did not (p = 0.04). We also found a weak, but significant correlation between LBP and waist circumference (r = 0.10, p = 0.03). Moderate, yet significant correlations were observed between both LBP and sCD14 and several markers of systemic inflammation (r = 0.1–0.23; p < 0.001–0.04).Conclusion: The trend for increased prevalence of MetS observed with increasing quartiles of LBP seems to be mainly driven by central obesity in our male cohort. The associations between LBP, sCD14 and systemic inflammation, indicate a potential role of the innate immune system in MetS.Trial registrationCLINICALTRIALS.GOV, NCT00764010. Registered 01 October 2008—retrospectively registered,https://clinicaltrials.gov/ct2/show/NCT00764010?term=NCT00764010&rank=1

Advanced glycation end products (AGEs) play a role in the development of late complications and atherosclerosis in diabetes by engaging the receptor for advanced glycation end products, RAGE. Receptor binding leads to activation of the vascular endothelium and increased inflammation in the vessel wall. The soluble variants of the receptor, endogenous secretory RAGE (esRAGE) and the cleaved cell-surface part of RAGE, which together comprise soluble RAGE (sRAGE), are suggested to have a protective effect acting as decoys for RAGE. We aimed to test whether high levels of soluble variants of RAGE could be protective against atherosclerosis development. Participants in the prospective atherosclerosis and childhood diabetes study were examined at baseline (aged 8–18) and at follow-up after 5 years. Both sRAGE and esRAGE were measured by immunoassay in 299 patients with type 1 diabetes and 112 healthy controls at baseline and 241 patients and 128 controls at follow-up. The AGEs methylglyoxal-derived hydroimidazolone-1 (MG-H1) and carboxymethyllysine (CML) were measured by immunoassay. The surrogate markers of atherosclerosis assessed were carotid intima-media thickness (cIMT), C-reactive protein (CRP) and Young’s modulus, measures of arterial wall thickness, inflammation and arterial stiffness, respectively. Levels of sRAGE and esRAGE correlated strongly both at baseline and at follow-up in both diabetes patients and controls. With increasing age, mean values of both variants declined, independent of gender, diabetes or pubertal stage. In the diabetes group, multiple regression analysis showed a positive association between both variants of soluble RAGE and cIMT. There was no significant relationship with Young’s modulus, but a negative association between sRAGE at baseline and CRP at follow-up. The ratios between the AGEs and the variants of soluble RAGE were increased in diabetes patients compared to controls. The results show a possible protective effect of high levels of sRAGE at baseline against inflammation 5 years later, but not on arterial stiffness or wall thickness, in this cohort of adolescents and young adults with T1D.

Short telomeres have been associated with ageing and cardiovascular disease. The influence on leukocyte telomere length (LTL) of long-term intervention with combined selenium and coenzyme Q₁₀ is unknown. Our aim was to determine whether 42 months of selenium and coenzyme Q₁₀ supplementation prevented telomere attrition and further cardiovascular mortality. The investigation is an explorative sub-study of a double-blind, placebo-controlled, randomized trial. Swedish citizens low in selenium (n = 118), aged 70–80 years, were included. Intervention time was 4 years, with 10 years’ follow-up time. LTL was relatively quantified with PCR at baseline and after 42 months. At baseline, LTL (SD) was 0.954 (0.260) in the active treatment group and 1.018 (0.317) in the placebo group (p = 0.23). At 42 months, less shortening of LTL was observed after active treatment compared with placebo (+0.019 vs. −0.129, respectively, p = 0.02), with a significant difference in change basing the analysis on individual changes in LTL (p < 0.001). Subjects suffering future death presented with significantly shorter LTL at 42 months than survivors [0.791 (0.190) vs. 0.941 (0.279), p = 0.01], with a significant difference in change of LTL according to cardiovascular mortality and survival (p = 0.03). To conclude, preservation of LTL after selenium and coenzyme Q₁₀ supplementation associated with reduced cardiovascular mortality.