Mechanisms of inhibition and activation of extrasynaptic αß GABAA receptors.

Type A GABA (γ-aminobutyric acid) receptors represent a diverse population in the mammalian brain, forming pentamers from combinations of α-, ß-, γ-, δ-, ε-, ρ-, θ- and π-subunits1. αß, α4ßδ, α6ßδ and α5ßγ receptors favour extrasynaptic localization, and mediate an essential persistent (tonic) inhibitory conductance in many regions of the mammalian brain1,2. Mutations of these receptors in humans are linked to epilepsy and insomnia3,4. Altered extrasynaptic receptor function is implicated in insomnia, stroke and Angelman and Fragile X syndromes1,5, and drugs targeting these receptors are used to treat postpartum depression6. Tonic GABAergic responses are moderated to avoid excessive suppression of neuronal communication, and can exhibit high sensitivity to Zn2+ blockade, in contrast to synapse-preferring α1ßγ, α2ßγ and α3ßγ receptor responses5,7-12. Here, to resolve these distinctive features, we determined structures of the predominantly extrasynaptic αß GABAA receptor class. An inhibited state bound by both the lethal paralysing agent α-cobratoxin13 and Zn2+ was used in comparisons with GABA-Zn2+ and GABA-bound structures. Zn2+ nullifies the GABA response by non-competitively plugging the extracellular end of the pore to block chloride conductance. In the absence of Zn2+, the GABA signalling response initially follows the canonical route until it reaches the pore. In contrast to synaptic GABAA receptors, expansion of the midway pore activation gate is limited and it remains closed, reflecting the intrinsic low efficacy that characterizes the extrasynaptic receptor. Overall, this study explains distinct traits adopted by αß receptors that adapt them to a role in tonic signalling.

Presynaptic hyperexcitability reversed by positive allosteric modulation of a GABABR epilepsy variant.

GABABRs are key membrane proteins that continually adapt the excitability of the nervous system. These G-protein coupled receptors are activated by the brain's premier inhibitory neurotransmitter GABA. They are obligate heterodimers composed of GABA-binding GABABR1 and G-protein-coupling GABABR2 subunits. Recently, three variants (G693W, S695I, I705N) have been identified in the gene (GABBR2) encoding for GABABR2. Individuals that harbour any of these variants exhibit severe developmental epileptic encephalopathy and intellectual disability, but the underlying pathogenesis that is triggered in neurons, remains unresolved. Using a range of confocal imaging, flow cytometry, structural modelling, biochemistry, live cell Ca2+ imaging of presynaptic terminals, whole-cell electrophysiology of HEK-293T cells and neurons, and two-electrode voltage clamping of Xenopus oocytes we have probed the biophysical and molecular trafficking and functional profiles of G693W, S695I and I705N variants. We report that all three point mutations impair neuronal cell surface expression of GABABRs, reducing signalling efficacy. However, a negative effect evident for one variant perturbed neurotransmission by elevating presynaptic Ca2+ signalling. This is reversed by enhancing GABABR signalling via positive allosteric modulation. Our results highlight the importance of studying neuronal receptors expressed in nervous system tissue and provide new mechanistic insights into how GABABR variants can initiate neurodevelopmental disease whilst highlighting the translational suitability and therapeutic potential of allosteric modulation for correcting these deficits.

Low-Density Lipoprotein Cholesterol Is Predominantly Associated With Atherosclerotic Cardiovascular Disease Events in Patients With Evidence of Coronary Atherosclerosis: The Western Denmark Heart Registry.

BACKGROUND: Low-density lipoprotein cholesterol (LDL-C) is an important causal risk factor for atherosclerotic cardiovascular disease (ASCVD). However, a sizable proportion of middle-aged individuals with elevated LDL-C level have not developed coronary atherosclerosis as assessed by coronary artery calcification (CAC). Whether presence of CAC modifies the association of LDL-C with ASCVD risk is unknown. We evaluated the association of LDL-C with future ASCVD events in patients with and without CAC. METHODS: The study included 23 132 consecutive symptomatic patients evaluated for coronary artery disease using coronary computed tomography angiography (CTA) from the Western Denmark Heart Registry, a seminational, multicenter-based registry with longitudinal registration of patient and procedure data. We assessed the association of LDL-C level obtained before CTA with ASCVD (myocardial infarction and ischemic stroke) events occurring during follow-up stratified by CAC>0 versus CAC=0 using Cox regression models adjusted for baseline characteristics. Outcomes were identified through linkage among national registries covering all hospitals in Denmark. We replicated our results in the National Heart, Lung, and Blood Institute-funded Multi-Ethnic Study of Atherosclerosis. RESULTS: During a median follow-up of 4.3 years, 552 patients experienced a first ASCVD event. In the overall population, LDL-C (per 38.7 mg/dL increase) was associated with ASCVD events occurring during follow-up (adjusted hazard ratio [aHR], 1.14 [95% CI, 1.04-1.24]). When stratified by the presence or absence of baseline CAC, LDL-C was only associated with ASCVD in the 10 792/23 132 patients (47%) with CAC>0 (aHR, 1.18 [95% CI, 1.06-1.31]); no association was observed among the 12 340/23 132 patients (53%) with CAC=0 (aHR, 1.02 [95% CI, 0.87-1.18]). Similarly, a very high LDL-C level (>193 mg/dL) versus LDL-C <116 mg/dL was associated with ASCVD in patients with CAC>0 (aHR, 2.42 [95% CI, 1.59-3.67]) but not in those without CAC (aHR, 0.92 [0.48-1.79]). In patients with CAC=0, diabetes, current smoking, and low high-density lipoprotein cholesterol levels were associated with future ASCVD events. The principal findings were replicated in the Multi-Ethnic Study of Atherosclerosis. CONCLUSIONS: LDL-C appears to be almost exclusively associated with ASCVD events over ≈5 years of follow-up in middle-aged individuals with versus without evidence of coronary atherosclerosis. This information is valuable for individualized risk assessment among middle-aged people with or without coronary atherosclerosis.

Oropharyngeal Microbiota Clusters in Children with Asthma or Wheeze Associate with Allergy, Blood Transcriptomic Immune Pathways, and Exacerbation Risk.

Rationale: Children with preschool wheezing or school-age asthma are reported to have airway microbial imbalances. Objectives: To identify clusters in children with asthma or wheezing using oropharyngeal microbiota profiles. Methods: Oropharyngeal swabs from the U-BIOPRED (Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes) pediatric asthma or wheezing cohort were characterized using 16S ribosomal RNA gene sequencing, and unsupervised hierarchical clustering was performed on the Bray-Curtis ß-diversity. Enrichment scores of the Molecular Signatures Database hallmark gene sets were computed from the blood transcriptome using gene set variation analysis. Children with severe asthma or severe wheezing were followed up for 12-18 months, with assessment of the frequency of exacerbations. Measurements and Main Results: Oropharyngeal samples from 241 children (age range, 1-17 years; 40% female) revealed four taxa-driven clusters dominated by Streptococcus, Veillonella, Rothia, and Haemophilus. The clusters showed significant differences in atopic dermatitis, grass pollen sensitization, FEV1% predicted after salbutamol, and annual asthma exacerbation frequency during follow-up. The Veillonella cluster was the most allergic and included the highest percentage of children with two or more exacerbations per year during follow-up. The oropharyngeal clusters were different in the enrichment scores of TGF-ß (transforming growth factor-ß) (highest in the Veillonella cluster) and Wnt/ß-catenin signaling (highest in the Haemophilus cluster) transcriptomic pathways in blood (all q values <0.05). Conclusions: Analysis of the oropharyngeal microbiota of children with asthma or wheezing identified four clusters with distinct clinical characteristics (phenotypes) that associate with risk for exacerbation and transcriptomic pathways involved in airway remodeling. This suggests that further exploration of the oropharyngeal microbiota may lead to novel pathophysiologic insights and potentially new treatment approaches.

Serial troponin-T and long-term outcomes in suspected acute coronary syndrome.

BACKGROUND: Long-term prognostic implications of serial high-sensitivity troponin concentrations in subjects with suspected acute coronary syndrome are unknown. METHODS AND RESULTS: Individuals with a first diagnosis of myocardial infarction, unstable angina, observation for suspected myocardial infarction, or chest pain from 2012 through 2019 who underwent two high-sensitivity troponin-T (hsTnT) measurements 1-7 h apart were identified through Danish national registries. Absolute and relative risks for death at days 0-30 and 31-365, stratified for whether subjects had normal or elevated hsTnT concentrations, and whether these concentrations changed by <20%, > 20 to 50%, or >50% in either direction from first to second measurement, were calculated through multivariable logistic regression with average treatment effect modeling. Of the 28 902 individuals included, 2.8% had died at 30 days, whereas 4.9% of those who had survived the first 30 days died between days 31-365. The standardized risk of death was highest among subjects with two elevated hsTnT concentrations (0-30 days: 4.3%, 31-365 days: 7.2%). In this group, mortality was significantly higher in those with a > 20 to 50% or >50% rise from first to second measurement, though only at 30 days. The risk of death was very low in subjects with two normal hsTnT concentrations (0-30 days: 0.1%, 31-365 days: 0.9%) and did not depend on relative or absolute changes between measurements. CONCLUSIONS: Individuals with suspected acute coronary syndrome and two consecutively elevated hsTnT concentrations consistently had the highest risk of death. Mortality was very low in subjects with two normal hsTnT concentrations, irrespective of changes between measurements.

Warmer winters result in reshaping of the European beech forest soil microbiome (bacteria, archaea and fungi)-With potential implications for ecosystem functioning.

In temperate regions, climate warming alters temperature and precipitation regimes. During winter, a decline in insulating snow cover changes the soil environment, where especially frost exposure can have severe implications for soil microorganisms and subsequently for soil nutrient dynamics. Here, we investigated winter climate change responses in European beech forests soil microbiome. Nine study sites with each three treatments (snow exclusion, insolation, and ambient) were investigated. Long-term adaptation to average climate was explored by comparing across sites. Triplicated treatment plots were used to evaluate short-term (one single winter) responses. Community profiles of bacteria, archaea and fungi were created using amplicon sequencing. Correlations between the microbiome, vegetation and soil physicochemical properties were found. We identify core members of the forest-microbiome and link them to key processes, for example, mycorrhizal symbiont and specialized beech wood degraders (fungi) and nitrogen cycling (bacteria, archaea). For bacteria, the shift of the microbiome composition due to short-term soil temperature manipulations in winter was similar to the community differences observed between long-term relatively cold to warm conditions. The results suggest a strong link between the changes in the microbiomes and changes in environmental processes, for example, nitrogen dynamics, driven by variations in winter climate.

ApoB and Non-HDL Cholesterol Versus LDL Cholesterol for Ischemic Stroke Risk.

OBJECTIVE: Conflicting results have been reported on the association between lipids and risk of ischemic stroke. We tested the hypothesis that the burden of ischemic stroke attributable to either elevated apolipoprotein B (apoB) or non-high-density lipoprotein (non-HDL) cholesterol is higher than that attributable to elevated low-density lipoprotein (LDL) cholesterol. METHODS: We included 104,618 individuals from an ongoing cohort study, the Copenhagen General Population Study. The associations of quintiles of apoB, non-HDL cholesterol, and LDL cholesterol with risk of ischemic stroke were estimated by Cox proportional hazards regressions with 95% confidence intervals. With 1st quintile as reference, the proportion of ischemic stroke attributable to the 2nd , 3rd , 4th , and 5th quintiles of apoB, non-HDL cholesterol, and LDL cholesterol were estimated by population attributable fractions. RESULTS: Higher quintiles of apoB and non-HDL cholesterol were associated with increased risk of ischemic stroke (both trends: p < 0.0001), whereas for LDL cholesterol this association was somewhat attenuated (trend: p = 0.0005). A similar pattern was seen for population attributable fraction values. Compared to individuals in the 1st quintile, the combined proportion of ischemic stroke attributable to individuals in the 2nd to 5th quintiles was 16.3% for apoB (levels >82 mg/dL), 14.7% for non-HDL cholesterol (>3.0 mmol/L; >117 mg/dL), and 6.8% for LDL cholesterol (>2.4 mmol/L; >94 mg/dL). INTERPRETATION: The proportion of ischemic stroke attributable to either elevated apoB or non-HDL cholesterol was double that attributable to elevated LDL cholesterol. ANN NEUROL 2022;92:379-389.

Triglycerides and risk of cardiovascular events in statin-treated patients with newly diagnosed type 2 diabetes: a Danish cohort study.

BACKGROUND: Elevated triglyceride levels are a clinically useful marker of remnant cholesterol. It is unknown whether triglycerides are associated with residual cardiovascular risk in CVD-naïve patients with newly diagnosed type 2 diabetes mellitus (T2DM), who are already on statin therapy. We aimed to assess the association between triglyceride levels and risk of major cardiovascular events (MACE) in statin-treated patients with newly diagnosed T2DM managed in routine clinical care. METHODS: This cohort study included newly diagnosed T2DM patients without a previous diagnosis of cardiovascular disease in Northern Denmark during 2005-2017. Individual triglyceride levels while on statin treatment were assessed within 1 year after T2DM diagnosis. The primary outcome was a composite of myocardial infarction, ischemic stroke, or cardiac death (MACE). Patients were followed from one year after T2DM diagnosis until 30 April 2021, MACE, emigration, or death. We used Cox regression to compute hazard ratios (HRs) controlling for confounding factors. RESULTS: Among 27,080 statin-treated patients with T2DM (median age 63 years; 53% males), triglyceride levels were < 1.0 mmol/L in 17%, 1.0-1.9 mmol/L in 52%, 2.0-2.9 mmol/L in 20%, and ≥ 3.0 mmol/L in 11%. During follow-up, 1,957 incident MACE events occurred (11.0 per 1000 person-years). Compared with triglyceride levels < 1.0 mmol/L, confounder-adjusted HRs for incident MACE were 1.14 (95% CI 1.00-1.29) for levels between 1.0 and 1.9 mmol/L, 1.30 (95% CI 1.12-1.51) for levels between 2.0 and 2.9 mmol/L, and 1.44 (95% CI 1.20-1.73) for levels ≥ 3.0 mmol/L. This association was primarily driven by higher rates of myocardial infarction and cardiac death and attenuated only slightly after additional adjustment for LDL cholesterol. Spline analyses confirmed a linearly increasing risk of MACE with higher triglyceride levels. Stratified analyses showed that the associations between triglyceride levels and MACE were stronger among women. CONCLUSIONS: In statin-treated patients with newly diagnosed T2DM, triglyceride levels are associated with MACE already from 1.0 mmol/L. This suggests that high triglyceride levels are a predictor of residual cardiovascular risk in early T2DM and could be used to guide allocation of additional lipid-lowering therapies for CVD prevention.

Primary prevention statin therapy in older adults.

PURPOSE OF REVIEW: The purpose of this review is to assess the evidence for primary prevention statin treatment in older adults, within the context of the most recent guideline recommendations, while also highlighting important considerations for shared decision-making. RECENT FINDINGS: As the average lifespan increases and the older adult population grows, the opportunity for prevention of morbidity and mortality from cardiovascular disease is magnified. Randomized trials and meta-analyses have demonstrated a clear benefit for primary prevention statin use through age 75, with uncertainty beyond that age. Despite these data supporting their use, current guidelines conflict in their statin treatment recommendations in those aged 70-75 years. Reflecting the paucity of evidence, the same guidelines are equivocal around primary prevention statins in those beyond age 75. Two large ongoing randomized trials (STAREE and PREVENTABLE) will provide additional insights into the treatment benefits and risks of primary prevention statins in the older adult population. In the meantime, a holistic approach in treatment decisions remains paramount for older patients. SUMMARY: The benefits of primary prevention statin treatment are apparent through age 75, which is reflected in the current ACC/AHA and USPSTF recommendations. Ongoing trials will clarify the utility in those beyond age 75.

Coronary artery calcium testing in young adults.

PURPOSE OF REVIEW: To provide a summary of recent literature on coronary artery calcium testing (CAC) for risk stratification in young adults <45 years old. RECENT FINDINGS: One of every ten young adults in the general population, and one out of every three young adults with traditional atherosclerotic cardiovascular disease (ASCVD) risk factors, have CAC. While the definition of premature CAC has yet to be formally defined in guidelines, it has become increasingly clear that any prevalent CAC among adults <45 years old should be considered premature. Traditional risk factors are strong predictors of CAC in young adults; however, this association has been found to wane over the life course which suggests that the onset and severity of risk factors for calcific atherosclerosis varies as individuals age. Though CAC is a robust predictor of both ASCVD and cancer-related mortality in old age, CAC in young adults confers a stepwise higher risk uniquely for incident ASCVD mortality, and not for non-ASCVD causes. New tools are available to assist in interpretation of CAC in the young, and for estimating the ideal age to initiate CAC scoring. SUMMARY: The identification of premature CAC is important because it suggests that calcific plaque can be detected with modern imaging earlier in the natural history than previously thought. Taken together, these findings underline a utility of selective use of CAC scoring on non-contrast computed tomography among at-risk young adults to facilitate timely lifestyle modification and pharmacotherapies for the prevention of later life ASCVD.

Dual antithrombotic treatment in chronic coronary syndrome: European Society of Cardiology criteria vs. CHADS-P2A2RC score.

AIMS: According to the 2019 European Society of Cardiology (ESC) guidelines on chronic coronary syndromes (CCS), adding a P2Y12 inhibitor or rivaroxaban to aspirin should be considered in high-risk patients. We estimated the proportion of patients eligible for treatment with the ESC criteria and examined if a recently validated risk score (CHADS-P2A2RC) could improve risk prediction. METHODS AND RESULTS: We included 61 338 CCS patients undergoing first-time coronary angiography in Western Denmark (2003-16) and classified them according to the ESC criteria and the CHADS-P2A2RC score. The ESC criteria identified 33.9% as high risk, 53.3% as moderate risk, and 12.8% as low risk. The CHADS-P2A2RC score identified 24.9% as high risk (≥4 points), 48.1% as moderate risk (2-3 points), and 27.0% as low risk (≤1 points). Major adverse cardiovascular events per 100 person-years were 4.8 [95% confidence interval (CI) 4.6-5.0] in patients considered high risk with both schemes, 2.1 (95% CI 2.0-2.2) in patients considered high risk with the ESC but low-to-moderate risk with the CHADS-P2A2RC criteria, 3.8 (95% CI 3.6-4.1) in patients considered low-to-moderate risk with the ESC but high risk with the CHADS-P2A2RC criteria, and 1.5 (95% CI 1.5-1.6) in patients considered low-to-moderate risk with both schemes. The CHADS-P2A2RC score enabled correct downward risk reclassification of 5161 patients (8%) without events, yielding an improved specificity of 9.7%, a loss of sensitivity of 4.4%, and an overall net reclassification index of 0.053. CONCLUSION: Based on the 2019 ESC guidelines, dual antithrombotic treatment should be considered in one-third of CCS patients. The CHADS-P2A2RC score improved risk classification and may particularly identify low-risk patients with limited benefit from treatment.

Very High Coronary Artery Calcium (≥1000) and Association With Cardiovascular Disease Events, Non-Cardiovascular Disease Outcomes, and Mortality: Results From MESA.

BACKGROUND: There are limited data on the unique cardiovascular disease (CVD), non-CVD, and mortality risks of primary prevention individuals with very high coronary artery calcium (CAC; ≥1000), especially compared with rates observed in secondary prevention populations. METHODS: Our study population consisted of 6814 ethnically diverse individuals 45 to 84 years of age who were free of known CVD from MESA (Multi-Ethnic Study of Atherosclerosis), a prospective, observational, community-based cohort. Mean follow-up time was 13.6±4.4 years. Hazard ratios of CAC ≥1000 were compared with both CAC 0 and CAC 400 to 999 for CVD, non-CVD, and mortality outcomes with the use of Cox proportional hazards regression adjusted for age, sex, and traditional risk factors. Using a sex-adjusted logarithmic model, we calculated event rates in MESA as a function of CAC and compared them with those observed in the placebo group of stable secondary prevention patients in the FOURIER clinical trial (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Subjects With Elevated Risk). RESULTS: Compared with CAC 400 to 999, those with CAC ≥1000 (n=257) had a greater mean number of coronary vessels with CAC (3.4±0.5), greater total area of CAC (586.5±275.2 mm2), similar CAC density, and more extensive extracoronary calcification. After full adjustment, CAC ≥1000 demonstrated a 4.71- (3.63-6.11), 7.57- (5.50-10.42), 4.86-(3.32-7.11), and 1.94-fold (1.57-2.41) increased risk for all CVD events, all coronary heart disease events, hard coronary heart disease events, and all-cause mortality, respectively, compared with CAC 0 and a 1.65- (1.25-2.16), 1.66- (1.22-2.25), 1.51- (1.03-2.23), and 1.34-fold (1.05-1.71) increased risk compared with CAC 400 to 999. With increasing CAC, hazard ratios increased for all event types, with no apparent upper CAC threshold. CAC ≥1000 was associated with a 1.95- (1.57-2.41) and 1.43-fold (1.12-1.83) increased risk for a first non-CVD event compared with CAC 0 and CAC 400 to 999, respectively. CAC 1000 corresponded to an annualized 3-point major adverse cardiovascular event rate of 3.4 per 100 person-years, similar to that of the total FOURIER population (3.3) and higher than those of the lower-risk FOURIER subgroups. CONCLUSIONS: Individuals with very high CAC (≥1000) are a unique population at substantially higher risk for CVD events, non-CVD outcomes, and mortality than those with lower CAC, with 3-point major adverse cardiovascular event rates similar to those of a stable treated secondary prevention population. Future guidelines should consider a less distinct stratification algorithm between primary and secondary prevention patients in guiding aggressive preventive pharmacotherapy.

The Airway Microbiota Modulates Effect of Azithromycin Treatment for Episodes of Recurrent Asthma-like Symptoms in Preschool Children: A Randomized Clinical Trial.

Rationale: Childhood asthma is often preceded by recurrent episodes of asthma-like symptoms, which can be triggered by both viral and bacterial agents. Recent randomized controlled trials have shown that azithromycin treatment reduces episode duration and severity through yet undefined mechanisms. Objectives: To study the influence of the airway microbiota on the effect of azithromycin treatment during acute episodes of asthma-like symptoms. Methods: Children from the COPSAC2010 (Copenhagen Prospective Studies on Asthma in Childhood 2010) cohort with recurrent asthma-like symptoms aged 12-36 months were randomized during acute episodes to azithromycin or placebo as previously reported. Before randomization, hypopharyngeal aspirates were collected and examined by 16S ribosomal RNA gene amplicon sequencing. Measurements and Main Results: In 139 airway samples from 68 children, episode duration after randomization was associated with microbiota richness (7.5% increased duration per 10 additional operational taxonomic units [OTUs]; 95% confidence interval, 1-14%; P = 0.025), with 15 individual OTUs (including several Neisseria and Veillonella), and with microbial pneumotypes defined from weighted UniFrac distances (longest durations in a Neisseria-dominated pneumotype). Microbiota richness before treatment increased the effect of azithromycin by 10% per 10 additional OTUs, and more OTUs were positively versus negatively associated with an increased azithromycin effect (82 vs. 58; P = 0.0032). Furthermore, effect modification of azithromycin was found for five individual OTUs (three OTUs increased and two OTUs decreased the effect; q < 0.05). Conclusions: The airway microbiota in acute episodes of asthma-like symptoms is associated with episode duration and modifies the effect of azithromycin treatment of the episodes in preschool children with recurrent asthma-like symptoms. Clinical trial registered with www.clinicaltrials.gov (NCT01233297).

Urbanized microbiota in infants, immune constitution, and later risk of atopic diseases.

BACKGROUND: Urbanization is linked with an increased burden of asthma and atopic traits. A putative mechanism is insufficient exposure to beneficial microbes early in life, leading to immune dysregulation, as was previously shown for indoor microbial exposures. OBJECTIVE: Our aim was to investigate whether urbanization is associated with the microbiota composition in the infants' body and early immune function, and whether these contribute to the later risk of asthma and atopic traits. METHODS: We studied the prospective Copenhagen Prospective Studies on Asthma in Childhood 20102010 mother-child cohort of 700 children growing up in areas with different degrees of urbanization. During their first year of life, airway and gut microbiotas, as well as immune marker concentrations, were defined. When the children were 6 years of age, asthma and atopic traits were diagnosed by pediatricians. RESULTS: In adjusted analyses, the risk of asthma and aeroallergen sensitization were increased in urban infants. The composition of especially airway but also gut microbiotas differed between urban and rural infants. The living environment-related structure of the airway microbiota was already associated with immune mediator concentrations at 1 month of age. An urbanized structure of the airway and gut microbiotas was associated with an increased risk of asthma coherently during multiple time points and also with the risks of eczema and sensitization. CONCLUSION: Our findings suggest that urbanization-related changes in the infant microbiota may elevate the risk of asthma and atopic traits, probably via cross talk with the developing immune system. The airways may facilitate this effect, as they are open for colonization by environmental airborne microbes and serve as an immune interface.

Coronary Artery Calcium for Personalized Allocation of Aspirin in Primary Prevention of Cardiovascular Disease in 2019: The MESA Study (Multi-Ethnic Study of Atherosclerosis).

BACKGROUND: Recent American College of Cardiology/American Heart Association Primary Prevention Guidelines recommended considering low-dose aspirin therapy only among adults 40 to 70 years of age who are at higher atherosclerotic cardiovascular disease (ASCVD) risk but not at high risk of bleeding. However, it remains unclear how these patients are best identified. The present study aimed to assess the value of coronary artery calcium (CAC) for guiding aspirin allocation for primary prevention by using 2019 aspirin meta-analysis data on cardiovascular disease relative risk reduction and bleeding risk. METHODS: The study included 6470 participants from the MESA Study (Multi-Ethnic Study of Atherosclerosis). ASCVD risk was estimated using the pooled cohort equations, and 3 strata were defined: <5%, 5% to 20%, and >20%. All participants underwent CAC scoring at baseline, and CAC scores were stratified as =0, 1 to 99, ≥100, and ≥400. A 12% relative risk reduction in cardiovascular disease events was used for the 5-year number needed to treat (NNT5) calculations, and a 42% relative risk increase in major bleeding events was used for the 5-year number needed to harm (NNH5) estimations. RESULTS: Only 5% of MESA participants would qualify for aspirin consideration for primary prevention according to the American College of Cardiology/American Heart Association guidelines and using >20% estimated ASCVD risk to define higher risk. Benefit/harm calculations were restricted to aspirin-naive participants <70 years of age not at high risk of bleeding (n=3540). The overall NNT5 with aspirin to prevent 1 cardiovascular disease event was 476 and the NNH5 was 355. The NNT5 was also greater than or similar to the NNH5 among estimated ASCVD risk strata. Conversely, CAC≥100 and CAC≥400 identified subgroups in which NNT5 was lower than NNH5. This was true both overall (for CAC≥100, NNT5=140 versus NNH5=518) and within ASCVD risk strata. Also, CAC=0 identified subgroups in which the NNT5 was much higher than the NNH5 (overall, NNT5=1190 versus NNH5=567). CONCLUSIONS: CAC may be superior to the pooled cohort equations to inform the allocation of aspirin in primary prevention. Implementation of current 2019 American College of Cardiology/American Heart Association guideline recommendations together with the use of CAC for further risk assessment may result in a more personalized, safer allocation of aspirin in primary prevention. Confirmation of these findings in experimental settings is needed.

Elevated LDL cholesterol and increased risk of myocardial infarction and atherosclerotic cardiovascular disease in individuals aged 70-100 years: a contemporary primary prevention cohort.

BACKGROUND: Findings of historical studies suggest that elevated LDL cholesterol is not associated with increased risk of myocardial infarction and atherosclerotic cardiovascular disease in patients older than 70 years. We aimed to test this hypothesis in a contemporary population of individuals aged 70-100 years. METHODS: We included in our analysis individuals (aged 20-100 years) from the Copenhagen General Population Study (CGPS) who did not have atherosclerotic cardiovascular disease or diabetes at baseline and who were not taking statins. Standard hospital assays were used to measure LDL cholesterol. We calculated hazard ratios (HRs) and absolute event rates for myocardial infarction and atherosclerotic cardiovascular disease, and we estimated the number needed to treat (NNT) in 5 years to prevent one event. FINDINGS: Between Nov 25, 2003, and Feb 17, 2015, 91 131 individuals were enrolled in CGPS. During mean 7·7 (SD 3·2) years of follow-up (to Dec 7, 2018), 1515 individuals had a first myocardial infarction and 3389 had atherosclerotic cardiovascular disease. Risk of myocardial infarction per 1·0 mmol/L increase in LDL cholesterol was augmented for the overall population (HR 1·34, 95% CI 1·27-1·41) and was amplified for all age groups, particularly those aged 70-100 years. Risk of atherosclerotic cardiovascular disease was also raised per 1·0 mmol/L increase in LDL cholesterol overall (HR 1·16, 95% CI 1·12-1·21) and in all age groups, particularly those aged 70-100 years. Risk of myocardial infarction was also increased with a 5·0 mmol/L or higher LDL cholesterol (ie, possible familial hypercholesterolaemia) versus less than 3·0 mmol/L in individuals aged 80-100 years (HR 2·99, 95% CI 1·71-5·23) and in those aged 70-79 years (1·82, 1·20-2·77). Myocardial infarction and atherosclerotic cardiovascular disease events per 1000 person-years for every 1·0 mmol/L increase in LDL cholesterol were highest in individuals aged 70-100 years, with number of events lower with younger age. The NNT in 5 years to prevent one myocardial infarction or atherosclerotic cardiovascular disease event if all people were given a moderate-intensity statin was lowest for individuals aged 70-100 years, with the NNT increasing with younger age. INTERPRETATION: In a contemporary primary prevention cohort, people aged 70-100 years with elevated LDL cholesterol had the highest absolute risk of myocardial infarction and atherosclerotic cardiovascular disease and the lowest estimated NNT in 5 years to prevent one event. Our data are important for preventive strategies aimed at reducing the burden of myocardial infarction and atherosclerotic cardiovascular disease in the growing population aged 70-100 years. FUNDING: None.

Evaluation of coronary stenosis versus plaque burden for atherosclerotic cardiovascular disease risk assessment and management.

PURPOSE OF REVIEW: To provide a summary of recent literature on the relative impact of luminal stenosis versus atherosclerotic plaque burden in atherosclerotic cardiovascular disease (ASCVD) risk stratification and management. RECENT FINDINGS: Recent results from both randomized controlled clinical trials as well as observational cohort studies have demonstrated that ASCVD risk is mediated mainly by the extent of atherosclerotic disease burden rather than by the presence of coronary stenosis or inducible ischemia. Although patients with obstructive CAD are generally at higher risk for ASCVD events than patients with nonobstructive CAD, this is driven by a higher plaque burden in those with obstructive CAD. Accordingly, the ASCVD risk for a given plaque burden is similar in patients with and without obstructive CAD. Accompanying these observations are randomized controlled trial data, which show that optimization of medical therapy instead of early revascularization is most important for improving prognosis in patients with stable obstructive CAD. SUMMARY: Emerging evidence shows that atherosclerotic plaque burden, and not stenosis per se, is the main driver of ASCVD risk in patients with CAD. This information challenges the current paradigm of selecting patients for intensive secondary prevention measures based primarily on the presence of obstructive CAD.

Is There a Role of Coronary CTA in Primary Prevention? Current State and Future Directions.

PURPOSE OF REVIEW: Information on subclinical atherosclerosis burden provides prognostic information on atherosclerotic cardiovascular disease (ASCVD) risk beyond what can be achieved by traditional risk factors alone and may therefore improve allocation of preventive treatment in primary prevention. The purpose of this review is to discuss the potential role and value of assessing subclinical atherosclerosis using coronary artery calcium (CAC) versus computed tomography angiography (CTA) among asymptomatic patients in the context of current primary prevention cholesterol guidelines. RECENT FINDINGS: Since 2013, primary prevention cholesterol guidelines have lowered the treatment threshold for initiating statin therapy resulting in high statin eligibility and sensitivity for detecting ASCVD events. Thus, one of the main advantages of assessing subclinical atherosclerosis is to identify those individuals who are at so low ASCVD risk that preventive treatment may safely be withhold. Numerous studies have shown that both CAC and CTA provide highly valuable information on ASCVD risk in the individual patient. However, while extensive data exist regarding the ability of CAC to improve treatment allocation in the context of primary prevention guidelines, such data is sparse for CTA. Furthermore, there is no data to show that CTA improves risk classification and treatment allocation in primary prevention beyond what can be achieved by assessment of CAC. Although CTA provides important information regarding prognosis in symptomatic patients undergoing clinical CTA, there is no strong evidence to support its use in the primary prevention setting. Thus, the potential value of CTA in primary prevention is not clear and is currently not recommended by guidelines.

2019 vs. 2016 ESC/EAS statin guidelines for primary prevention of atherosclerotic cardiovascular disease.

AIMS: The 2019 vs. 2016 European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) dyslipidaemia guidelines contains new recommendations for primary prevention with statins; however, the potential impact of these changes is unclear. We compared the 2019 and 2016 guidelines regarding statin eligibility and potential impact on prevention of atherosclerotic cardiovascular disease (ASCVD) in the general population. METHODS AND RESULTS: We examined 45 750 individuals aged 40-75 from the Copenhagen General Population Study, all free of ASCVD and statin use at baseline. During the 9.2-year follow-up, 3337 experienced ASCVD (myocardial infarction, stroke, and cardiovascular death). For Class I/A recommendations, 32.3% (95% confidence interval: 31.8-32.7) and 15.4% (15.1-15.7) of individuals were statin eligible according to the 2019 and 2016 guidelines. The increased statin eligibility by the 2019 guidelines was explained by lower low-density lipoprotein cholesterol (LDL-C) thresholds alone (explaining 33.2%), older age range alone (49.4%), older age range in combination with lower LDL-C thresholds (14.7%), and updated SCORE risk algorithm (2.8%). If fully implemented, the estimated percentage of ASCVD events that can be prevented by using high-intensity statins for 10 years were 25% and 11% with the 2019 and 2016 guidelines. Mainly because of older age range in the 2019 guidelines, the corresponding estimated numbers needed to treat (NNT) to prevent one ASCVD event were 19 and 20. CONCLUSION: Due to lower LDL-C threshold and older age range, the 2019 vs. 2016 ESC/EAS guidelines doubles the number of individuals eligible for primary prevention with statins. This considerably improves the potential for ASCVD prevention in the general population, with similar NNT to prevent one event.