Evinacumab in homozygous familial hypercholesterolaemia: long-term safety and efficacy.

BACKGROUND AND AIMS: Homozygous familial hypercholesterolaemia (HoFH) is a rare genetic disorder characterized by severely elevated LDL cholesterol (LDL-C) and premature atherosclerotic cardiovascular disease. In the pivotal Phase 3 HoFH trial (NCT03399786), evinacumab significantly decreased LDL-C in patients with HoFH. This study assesses the long-term safety and efficacy of evinacumab in adult and adolescent patients with HoFH. METHODS: In this open-label, single-arm, Phase 3 trial (NCT03409744), patients aged ≥12 years with HoFH who were evinacumab-naïve or had previously received evinacumab in other trials (evinacumab-continue) received intravenous evinacumab 15 mg/kg every 4 weeks with stable lipid-lowering therapy. RESULTS: A total of 116 patients (adults: n = 102; adolescents: n = 14) were enrolled, of whom 57 (49.1%) were female. Patients were treated for a median (range) duration of 104.3 (28.3-196.3) weeks. Overall, treatment-emergent adverse events (TEAEs) and serious TEAEs were reported in 93 (80.2%) and 27 (23.3%) patients, respectively. Two (1.7%) deaths were reported (neither was considered related to evinacumab). Three (2.6%) patients discontinued due to TEAEs (none were considered related to evinacumab). From baseline to Week 24, evinacumab decreased mean LDL-C by 43.6% [mean (standard deviation, SD), 3.4 (3.2) mmol/L] in the overall population; mean LDL-C reduction in adults and adolescents was 41.7% [mean (SD), 3.2 (3.3) mmol/L] and 55.4% [mean (SD), 4.7 (2.5) mmol/L], respectively. CONCLUSIONS: In this large cohort of patients with HoFH, evinacumab was generally well tolerated and markedly decreased LDL-C irrespective of age and sex. Moreover, the efficacy and safety of evinacumab was sustained over the long term.

Unexpected gaps in knowledge of familial hypercholesterolaemia among Dutch general practitioners.

BACKGROUND: Familial hypercholesterolaemia (FH) warrants early diagnosis to prevent premature atherosclerotic cardiovascular disease (CVD). However, underdiagnosis and undertreatment of FH persist. This study aimed to assess the knowledge and practice of FH care among general practitioners (GPs) in the Netherlands. METHODS: An internationally standardised, online questionnaire was sent to Dutch GPs between February 2021 and July 2022. The survey assessed knowledge and awareness of FH, encompassing general familiarity, awareness of management guidelines, inheritance, prevalence, CVD risk, and clinical practice related to FH. Comparative analysis was performed using data on primary care physicians from Western Australia, the Asia-Pacific region and the United Kingdom. RESULTS: Of the 221 participating GPs, 62.4% rated their familiarity with FH as above average (score > 4 on a 1-7 scale), with 91.4% considering themselves familiar with FH treatment and referral guidelines. Correct identification of the FH definition, typical lipid profile, inheritance pattern, prevalence and CVD risk was reported by 83.7%, 87.8%, 55.7%, 19.5%, and 13.6% of the respondents, respectively. Of the participants, 58.4% answered fewer than half of the 8 knowledge questions correctly. Dutch GPs reported greater FH familiarity and guideline awareness compared with their international counterparts but exhibited similar low performance on FH knowledge questions. CONCLUSION: Despite the Netherlands' relatively high FH detection rate, substantial knowledge gaps regarding FH persist among Dutch GPs, mirroring global trends. Enhanced FH education and awareness in primary care are imperative to improve FH detection and ensure adequate treatment. Targeting the global suboptimal understanding of FH might require international efforts.

Enhanced identification of familial hypercholesterolemia using central laboratory algorithms.

BACKGROUND AND AIMS: Familial hypercholesterolemia (FH) is a highly prevalent genetic disorder resulting in markedly elevated LDL cholesterol levels and premature coronary artery disease. FH underdiagnosis and undertreatment require novel detection methods. This study evaluated the effectiveness of using an LDL cholesterol cut-off ≥99.5th percentile (sex- and age-adjusted) to identify clinical and genetic FH, and investigated underutilization of genetic testing and undertreatment in FH patients. METHODS: Individuals with at least one prior LDL cholesterol level ≥99.5th percentile were selected from a laboratory database containing lipid profiles of 590,067 individuals. The study comprised three phases: biochemical validation of hypercholesterolemia, clinical identification of FH, and genetic determination of FH. RESULTS: Of 5614 selected subjects, 2088 underwent lipid profile reassessment, of whom 1103 completed the questionnaire (mean age 64.2 ± 12.7 years, 48% male). In these 1103 subjects, mean LDL cholesterol was 4.0 ± 1.4 mmol/l and 722 (65%) received lipid-lowering therapy. FH clinical diagnostic criteria were met by 282 (26%) individuals, of whom 85% had not received guideline-recommended genetic testing and 97% failed to attain LDL cholesterol targets. Of 459 individuals consenting to genetic validation, 13% carried an FH-causing variant, which increased to 19% in clinically diagnosed FH patients. CONCLUSIONS: The identification of a substantial number of previously undiagnosed and un(der)treated clinical and genetic FH patients within a central laboratory database highlights the feasibility and clinical potential of this targeted screening strategy; both in identifying new FH patients and in improving treatment in this high-risk population.

Long-Term Efficacy and Tolerability of PCSK9 Targeted Therapy: A Review of the Literature.

Increased plasma levels of low-density lipoprotein cholesterol (LDL-C) are causally associated with atherosclerotic cardiovascular disease (ASCVD), and statins that lower LDL-C have been the cornerstone of ASCVD prevention for decades. However, guideline-recommended LDL-C targets are not achieved in about 60% of statin users. Proprotein convertase subtilisin/kexin type 9 (PCSK9)-targeted therapy effectively lowers LDL-C levels and has been shown to reduce ASCVD risk. A growing body of scientific and clinical evidence shows that PCSK9-targeted therapy offers an excellent safety and tolerability profile with a low incidence of side effects in the short term. In this review, we present and discuss the current clinical and scientific evidence pertaining to the long-term efficacy and tolerability of PCSK9-targeted therapy.

Beyond early LDL cholesterol lowering to prevent coronary atherosclerosis in familial hypercholesterolaemia.

AIMS: Familial hypercholesterolaemia (FH) patients are subjected to a high lifetime exposure to low density lipoprotein cholesterol (LDL-C), despite use of lipid-lowering therapy (LLT). This study aimed to quantify the extent of subclinical atherosclerosis and to evaluate the association between lifetime cumulative LDL-C exposure and coronary atherosclerosis in young FH patients. METHODS AND RESULTS: Familial hypercholesterolaemia patients, divided into a subgroup of early treated (LLT initiated <25 years) and late treated (LLT initiated ≥25 years) patients, and an age- and sex-matched unaffected control group, underwent coronary CT angiography (CCTA) with artificial intelligence-guided analysis. Ninety genetically diagnosed FH patients and 45 unaffected volunteers (mean age 41 ± 3 years, 51 (38%) female) were included. Familial hypercholesterolaemia patients had higher cumulative LDL-C exposure (181 ± 54 vs. 105 ± 33 mmol/L ∗ years) and higher prevalence of coronary plaque compared with controls (46 [51%] vs. 10 [22%], OR 3.66 [95%CI 1.62-8.27]). Every 75 mmol/L ∗ years cumulative exposure to LDL-C was associated with a doubling in per cent atheroma volume (total plaque volume divided by total vessel volume). Early treated patients had a modestly lower cumulative LDL-C exposure compared with late treated FH patients (167 ± 41 vs. 194 ± 61 mmol/L ∗ years; P = 0.045), without significant difference in coronary atherosclerosis. Familial hypercholesterolaemia patients with above-median cumulative LDL-C exposure had significantly higher plaque prevalence (OR 3.62 [95%CI 1.62-8.27]; P = 0.001), compared with patients with below-median exposure. CONCLUSION: Lifetime exposure to LDL-C determines coronary plaque burden in FH, underlining the need of early as well as potent treatment initiation. Periodic CCTA may offer a unique opportunity to monitor coronary atherosclerosis and personalize treatment in FH.

This study reveals that young patients with familial hypercholesterolaemia (FH), as compared with individuals without FH, have a higher build-up of coronary artery plaque, linked directly to their increased lifetime exposure to LDL cholesterol. Genetically confirmed FH patients have a higher coronary plaque burden than those without FH, with every 75 mmol/L ∗ years increase in lifetime cumulative LDL cholesterol exposure resulting in a two-fold increase in total plaque volume. Early and potent LDL cholesterol lowering treatments are crucial for FH patients to prevent future cardiovascular diseases.

Association Between Self-Rated Medication Adherence and Adverse Cardiovascular Outcomes in Patients With Hypertension.

Background Medication nonadherence contributes to poor health outcomes but remains challenging to identify. This study assessed the association between self-rated adherence and systolic blood pressure, low-density lipoprotein cholesterol levels, cardiovascular events, and all-cause mortality in SPRINT (Systolic Blood Pressure Intervention Trial). Methods and Results A total of 9361 patients randomized to 2 systolic blood pressure target groups, <120 mm Hg (intensive) and <140 mm Hg (standard), self-rated their medication adherence at each visit by marking a scale, ranging from 0% to 100%. Lower and high adherence were defined as scores ≤80% and >80%, respectively. Linear mixed effect regression models and Cox proportional hazard models were used to evaluate the association between self-rated adherence and systolic blood pressure and low-density lipoprotein cholesterol and cardiovascular events and all-cause mortality, respectively. A total of 9278 participants (mean age 68±9.4 years, 35.6% female) had repeated self-rated adherence measurements available, with a mean of 15±4 measurements per participant over 3.8 years follow-up. Of these, 2694 participants (29.0%) had ≥1 adherence measurements ≤80%. Compared with high-adherent patients, patients with lower adherence had significantly higher estimated on-treatment systolic blood pressure at 2-year follow-up: 128.7 (95% CI, 127.6-129.9) versus 120.0 (95% CI, 119.7-120.2) mm Hg in the intensive arm; and 139.8 (95% CI 138.4-141.1) versus 135.0 (95% CI 134.7-135.2) in the standard arm. Moreover, lower adherence was associated with an estimated 11 mg/dL higher low-density lipoprotein cholesterol level, more cardiovascular events (hazard ratio [HR], 1.69 [95% CI, 1.20-2.39]), and higher all-cause mortality (HR, 1.63 [95% CI, 1.16-2.31]). Conclusions Self-rated adherence allows identification of lower medication adherence and correlates with blood pressure control, low-density lipoprotein cholesterol levels, and adverse outcomes.

ANGPTL3 (Angiopoietin-Like 3) Preferentially Resides on High-Density Lipoprotein in the Human Circulation, Affecting Its Activity.

Background ANGPTL3 (angiopoietin-like protein 3) is an acknowledged crucial regulator of lipid metabolism by virtue of its inhibitory effect on lipoprotein lipase and endothelial lipase. It is currently unknown whether and to which lipoproteins ANGPTL3 is bound and whether the ability of ANGPTL3 to inhibit lipase activity is affected by binding to lipoproteins. Methods and Results Incubation of ultracentrifugation-isolated low-density lipoprotein (LDL) and high-density lipoprotein (HDL) fractions from healthy volunteers with recombinant ANGPTL3 revealed that ANGPTL3 associates with both HDL and LDL particles ex vivo. Plasma from healthy volunteers and a patient deficient in HDL was fractionated by fast protein liquid chromatography, and ANGPTL3 distribution among lipoprotein fractions was measured. In healthy volunteers, ≈75% of lipoprotein-associated ANGPTL3 resides in HDL fractions, whereas ANGPTL3 was largely bound to LDL in the patient deficient in HDL. ANGPTL3 activity was studied by measuring lipolysis and uptake of 3H-trioleate by brown adipocyte T37i cells. Unbound ANGPTL3 did not suppress lipase activity, but when given with HDL or LDL, ANGPTL3 suppressed lipase activity by 21.4±16.4% (P=0.03) and 25.4±8.2% (P=0.006), respectively. Finally, in a subset of the EPIC (European Prospective Investigation into Cancer) Norfolk study, plasma HDL cholesterol and amount of large HDL particles were both positively associated with plasma ANGPTL3 concentrations. Moreover, plasma ANGPTL3 concentrations showed a positive association with incident coronary artery disease (odds ratio, 1.25 [95% CI, 1.01-1.55], P=0.04). Conclusions Although ANGPTL3 preferentially resides on HDL, its activity was highest once bound to LDL particles.

Concordance of a High Lipoprotein(a) Concentration Among Relatives.

Importance: Lipoprotein(a) (Lp[a]) concentrations are a highly heritable and potential causal risk factor for atherosclerotic cardiovascular disease (ASCVD). Recent consensus statements by the European Atherosclerosis Society and American Heart Association recommend screening of relatives of individuals with high Lp(a) concentrations, but the expected yield of this approach has not been quantified in large populations. Objective: To measure the prevalence of high Lp(a) concentrations among first- and second-degree relatives of individuals with high Lp(a) concentrations compared with unrelated participants. Design, Setting, and Participants: In this cross-sectional analysis, pairs of first-degree (n = 19 899) and second-degree (n = 9715) relatives with measured Lp(a) levels from the UK Biobank study and random pairs of unrelated individuals (n = 184 764) were compared. Data for this study were collected from March 2006 to August 2010 and analyzed from December 2021 to August 2023. Exposure: Serum Lp(a) levels, with a high Lp(a) level defined as at least 125 nmol/L. Main Outcome and Measure: Concordance of clinically relevant high Lp(a) levels in first- and second-degree relatives of index participants with high Lp(a) levels. Results: A total of 52 418 participants were included in the analysis (mean [SD] age, 57.3 [8.0] years; 29 825 [56.9%] women). Levels of Lp(a) were correlated among pairs of first-degree (Spearman ρ = 0.45; P < .001) and second-degree (Spearman ρ = 0.22; P < .001) relatives. A total of 1607 of 3420 (47.0% [95% CI, 45.3%-48.7%]) first-degree and 514 of 1614 (31.8% [95% CI, 29.6%-34.2%]) second-degree relatives of index participants with high Lp(a) levels also had elevated concentrations compared with 4974 of 30 258 (16.4% [95% CI, 16.0%-16.9%]) pairs of unrelated individuals. The concordance in high Lp(a) levels was generally consistent among subgroups (eg, those with prior ASCVD, postmenopausal women, and statin users). The odds ratios for relatives to have high Lp(a) levels if their index relative had a high Lp(a) level compared with those whose index relatives did not have high Lp(a) levels were 7.4 (95% CI, 6.8-8.1) for first-degree relatives and 3.0 (95% CI, 2.7-3.4) for second-degree relatives. Conclusions and Relevance: The findings of this cross-sectional study suggest that the yield of cascade screening of first-degree relatives of individuals with high Lp(a) levels is over 40%. These findings support recent recommendations to use this approach to identify additional individuals at ASCVD risk based on Lp(a) concentrations.

Low-Cost High-Throughput Genotyping for Diagnosing Familial Hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) is a common but underdiagnosed genetic disorder characterized by high low-density lipoprotein cholesterol levels and premature cardiovascular disease. Current sequencing methods to diagnose FH are expensive and time-consuming. In this study, we evaluated the accuracy of a low-cost, high-throughput genotyping array for diagnosing FH. METHODS: An Illumina Global Screening Array was customized to include probes for 636 variants, previously classified as FH-causing variants. First, its theoretical coverage was assessed in all FH variant carriers diagnosed through next-generation sequencing between 2016 and 2022 in the Netherlands (n=1772). Next, the performance of the array was validated in another sample of FH variant carriers previously identified in the Dutch FH cascade screening program (n=1268). RESULTS: The theoretical coverage of the array for FH-causing variants was 91.3%. Validation of the array was assessed in a sample of 1268 carriers of whom 1015 carried a variant in LDLR, 250 in APOB, and 3 in PCSK9. The overall sensitivity was 94.7% and increased to 98.2% after excluding participants with variants not included in the array design. Copy number variation analysis yielded a 89.4% sensitivity. In 18 carriers, the array identified a total of 19 additional FH-causing variants. Subsequent DNA analysis confirmed 5 of the additionally identified variants, yielding a false-positive result in 16 subjects (1.3%). CONCLUSIONS: The FH genotyping array is a promising tool for genetically diagnosing FH at low costs and has the potential to greatly increase accessibility to genetic testing for FH. Continuous customization of the array will further improve its performance.

Use of Lipoprotein(a) to improve diagnosis and management in clinical familial hypercholesterolemia.

BACKGROUND AND AIMS: Lipoprotein(a) (Lp(a)) is an LDL-like particle whose plasma levels are largely genetically determined. The impact of measuring Lp(a) in patients with clinical familial hypercholesterolemia (FH) referred for genetic testing is largely unknown. We set out to evaluate the contribution of (genetically estimated) Lp(a) in a large nation-wide referral population of clinical FH. METHODS: In 1504 patients referred for FH genotyping, we used an LPA genetic instrument (rs10455872 and rs3798220) as a proxy for plasma Lp(a) levels. The genetic Lp(a) proxy was used to correct LDL-cholesterol and reclassify patients with clinical FH based on Dutch Lipid Criteria Network (DLCN) scoring. Finally, we used estimated Lp(a) levels to reclassify ASCVD risk using the SCORE and SMART risk scores. RESULTS: LPA SNPs were more prevalent among mutation-negative compared with mutation-positive patients (296/1280 (23.1%) vs 35/224 (15.6%), p = 0.016). Among patients with genetically defined high Lp(a) levels, 9% were reclassified to the DLCN category 'unlikely FH' using Lp(a)-corrected LDL-cholesterol (LDL-Ccor) and all but one of these patients indeed carried no FH variant. Furthermore, elevated Lp(a) reclassified predicted ASCVD risk into a higher category in up to 18% of patients. CONCLUSIONS: In patients referred for FH molecular testing, we show that taking into account (genetically estimated) Lp(a) levels not only results in reclassification of probability of genetic FH, but also has an impact on individual cardiovascular risk evaluation. However, to avoid missing the diagnosis of an FH variant, clear thresholds for the use of Lp(a)-cholesterol adjusted LDL-cholesterol levels in patients referred for genetic testing of FH must be established.

Joint Genetic Inhibition of PCSK9 and CETP and the Association With Coronary Artery Disease: A Factorial Mendelian Randomization Study.

Importance: Cholesteryl ester transfer protein inhibition (CETP) has been shown to increase levels of high-density lipoprotein cholesterol (HDL-C) and reduce levels of low-density lipoprotein cholesterol (LDL-C). Current LDL-C target attainment is low, and novel phase 3 trials are underway to investigate whether CETP inhibitors result in reduction of cardiovascular disease risk in high-risk patients who may be treated with PCSK9-inhibiting agents. Objective: To explore the associations of combined reduction of CETP and PCSK9 concentrations with risk of coronary artery disease (CAD) and other clinical and safety outcomes. Design, Setting, and Participants: Two-sample 2 × 2 factorial Mendelian randomization study in a general population sample that includes data for UK Biobank participants of European ancestry. Exposures: Separate genetic scores were constructed for CETP and PCSK9 plasma protein concentrations, which were combined to determine the associations of combined genetically reduced CETP and PCSK9 concentrations with disease. Main Outcomes and Measures: Blood lipid and lipoprotein concentrations, blood pressure, CAD, age-related macular degeneration, type 2 diabetes, any stroke and ischemic stroke, Alzheimer disease, vascular dementia, heart failure, atrial fibrillation, chronic kidney disease, asthma, and multiple sclerosis. Results: Data for 425 354 UKB participants were included; the median (IQR) age was 59 years (51-64), and 229 399 (53.9%) were female. The associations of lower CETP and lower PCSK9 concentrations with CAD are similar when scaled per 10-mg/dL reduction in LDL-C concentrations (CETP: odds ratio [OR], 0.74; 95% CI, 0.67 to 0.81; PCSK9: OR, 0.75; 95% CI, 0.71 to 0.79). Combined exposure to lower CETP and PCSK9 concentrations was associated with an additive magnitude with lipids and all outcomes, and we did not observe any nonadditive interactions, most notably for LDL-C (CETP: effect size, -1.11 mg/dL; 95% CI, -1.40 to -0.82; PCSK9: effect size, -2.13 mg/dL; 95% CI, -2.43 to -1.84; combined: effect size, -3.47 mg/dL; 95% CI, -3.76 to -3.18; P = .34 for interaction) and CAD (CETP: OR, 0.96; 95% CI, 0.94 to 1.00; PCSK9: OR, 0.94; 95% CI, 0.91 to 0.97; combined: OR, 0.90; 95% CI, 0.87 to 0.93; P = .83 for interaction). In addition, when corrected for multiple testing, lower CETP concentrations were associated with increased age-related macular degeneration (OR, 1.11; 95% CI, 1.04 to 1.19). Conclusions and Relevance: Our results suggest that joint inhibition of CETP and PCSK9 has additive effects on lipid traits and disease risk, including a lower risk of CAD. Further research may explore whether a combination of CETP- and PCSK9-related therapeutics can benefit high-risk patients who are unable to reach treatment targets with existing options.

Experimental Conditions That Influence the Utility of 2'7'-Dichlorodihydrofluorescein Diacetate (DCFH2-DA) as a Fluorogenic Biosensor for Mitochondrial Redox Status.

Oxidative stress has been causally linked to various diseases. Electron transport chain (ETC) inhibitors such as rotenone and antimycin A are frequently used in model systems to study oxidative stress. Oxidative stress that is provoked by ETC inhibitors can be visualized using the fluorogenic probe 2',7'-dichlorodihydrofluorescein-diacetate (DCFH2-DA). Non-fluorescent DCFH2-DA crosses the plasma membrane, is deacetylated to 2',7'-dichlorodihydrofluorescein (DCFH2) by esterases, and is oxidized to its fluorescent form 2',7'-dichlorofluorescein (DCF) by intracellular ROS. DCF fluorescence can, therefore, be used as a semi-quantitative measure of general oxidative stress. However, the use of DCFH2-DA is complicated by various protocol-related factors that mediate DCFH2-to-DCF conversion independently of the degree of oxidative stress. This study therefore analyzed the influence of ancillary factors on DCF formation in the context of ETC inhibitors. It was found that ETC inhibitors trigger DCF formation in cell-free experiments when they are co-dissolved with DCFH2-DA. Moreover, the extent of DCF formation depended on the type of culture medium that was used, the pH of the assay system, the presence of fetal calf serum, and the final DCFH2-DA solvent concentration. Conclusively, experiments with DCFH2-DA should not discount the influence of protocol-related factors such as medium and mitochondrial inhibitors (and possibly other compounds) on the DCFH2-DA-DCF reaction and proper controls should always be built into the assay protocol.

Optimal Use of 2',7'-Dichlorofluorescein Diacetate in Cultured Hepatocytes.

Oxidative stress is a state that arises when the production of reactive transients overwhelms the cell's capacity to neutralize the oxidants and radicals. This state often coincides with the pathogenesis and perpetuation of numerous chronic diseases. On the other hand, medical interventions such as radiation therapy and photodynamic therapy generate radicals to selectively damage and kill diseased tissue. As a result, the qualification and quantification of oxidative stress are of great interest to those studying disease mechanisms as well as therapeutic interventions. 2',7'-Dichlorodihydrofluorescein-diacetate (DCFH2-DA) is one of the most widely used fluorogenic probes for the detection of reactive transients. The nonfluorescent DCFH2-DA crosses the plasma membrane and is deacetylated by cytosolic esterases to 2',7'-dichlorodihydrofluorescein (DCFH2). The nonfluorescent DCFH2 is subsequently oxidized by reactive transients to form the fluorescent 2',7'-dichlorofluorescein (DCF). The use of DCFH2-DA in hepatocyte-derived cell lines is more challenging because of membrane transport proteins that interfere with probe uptake and retention, among several other reasons. Cancer cells share some of the physiological and biochemical features with hepatocytes, so probe-related technical issues are applicable to cultured malignant cells as well. This study therefore analyzed the in vitro properties of DCFH2-DA in cultured human hepatocytes (HepG2 cells and differentiated and undifferentiated HepaRG cells) to identify methodological and technical features that could impair proper data analysis and interpretation. The main issues that were found and should therefore be accounted for in experimental design include the following: (1) both DCFH2-DA and DCF are taken up rapidly, (2) DCF is poorly retained in the cytosol and exits the cell, (3) the rate of DCFH2 oxidation is cell type-specific, (4) DCF fluorescence intensity is pH-dependent at pH < 7, and (5) the stability of DCFH2-DA in cell culture medium relies on medium composition. Based on the findings, the conditions for the use of DCFH2-DA in hepatocyte cell lines were optimized. Finally, the optimized protocol was reduced to practice and DCFH2-DA was applied to visualize and quantify oxidative stress in real time in HepG2 cells subjected to anoxia/reoxygenation as a source of reactive transients.

Lipoprotein(a), venous thromboembolism and COVID-19: A pilot study.

BACKGROUND AND AIMS: Thrombosis is a major driver of adverse outcome and mortality in patients with Coronavirus disease 2019 (COVID-19). Hypercoagulability may be related to the cytokine storm associated with COVID-19, which is mainly driven by interleukin (IL)-6. Plasma lipoprotein(a) [Lp(a)] levels increase following IL-6 upregulation and Lp(a) has anti-fibrinolytic properties. This study investigated whether Lp(a) elevation may contribute to the pro-thrombotic state hallmarking COVID-19 patients. METHODS: Lp(a), IL-6 and C-reactive protein (CRP) levels were measured in 219 hospitalized patients with COVID-19 and analyzed with linear mixed effects model. The baseline biomarkers and increases during admission were related to venous thromboembolism (VTE) incidence and clinical outcomes in a Kaplan-Meier and logistic regression analysis. RESULTS: Lp(a) levels increased significantly by a mean of 16.9 mg/dl in patients with COVID-19 during the first 21 days after admission. Serial Lp(a) measurements were available in 146 patients. In the top tertile of Lp(a) increase, 56.2% of COVID-19 patients experienced a VTE event compared to 18.4% in the lowest tertile (RR 3.06, 95% CI 1.61-5.81; p < 0.001). This association remained significant after adjusting for age, sex, IL-6 and CRP increase and number of measurements. Increases in IL-6 and CRP were not associated with VTE. Increase in Lp(a) was strongly correlated with increase in IL-6 (r = 0.44, 95% CI 0.30-0.56, p < 0.001). CONCLUSIONS: Increases in Lp(a) levels during the acute phase of COVID-19 were strongly associated with VTE incidence. The acute increase in anti-fibrinolytic Lp(a) may tilt the balance to VTE in patients hospitalized for COVID-19.

Assessment of practical applicability and clinical relevance of a commonly used LDL-C polygenic score in patients with severe hypercholesterolemia.

BACKGROUND AND AIMS: Low-density lipoprotein cholesterol (LDL-C) levels vary in patients with familial hypercholesterolemia (FH) and can be explained by a single deleterious genetic variant or by the aggregate effect of multiple, common small-effect variants that can be captured in a polygenic score (PS). We set out to investigate the contribution of a previously published PS to the inter-individual LDL-C variation and coronary artery disease (CAD) risk in patients with a clinical FH phenotype. METHODS: First, in a cohort of 628 patients referred for genetic FH testing, we evaluated the distribution of a PS for LDL-C comprising 12 genetic variants. Next, we determined its association with coronary artery disease (CAD) risk using UK Biobank data. RESULTS: The mean PS was higher in 533 FH-variant-negative patients (FH/M-) compared with 95 FH-variant carriers (1.02 vs 0.94, p < 0.001). 39% of all patients had a PS equal to the top 20% from a population-based reference cohort and these patients were less likely to carry an FH variant (OR 0.22, 95% CI 0.10-0.48) compared with patients in the lowest 20%. In UK Biobank data, the PS explained 7.4% of variance in LDL-C levels and was associated with incident CAD. Addition of PS to a prediction model using age and sex and LDL-C did not increase the c-statistic for predicting CAD risk. CONCLUSIONS: This 12-variant PS was higher in FH/M- patients and associated with incident CAD in UK Biobank data. However, the PS did not improve predictive accuracy when added to the readily available characteristics age, sex and LDL-C, suggesting limited discriminative value for CAD.

Next-generation sequencing to confirm clinical familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia is characterised by high low-density lipoprotein-cholesterol levels and is caused by a pathogenic variant in LDLR, APOB or PCSK9. We investigated which proportion of suspected familial hypercholesterolemia patients was genetically confirmed, and whether this has changed over the past 20 years in The Netherlands. METHODS: Targeted next-generation sequencing of 27 genes involved in lipid metabolism was performed in patients with low-density lipoprotein-cholesterol levels greater than 5 mmol/L who were referred to our centre between May 2016 and July 2018. The proportion of patients carrying likely pathogenic or pathogenic variants in LDLR, APOB or PCSK9, or the minor familial hypercholesterolemia genes LDLRAP1, ABCG5, ABCG8, LIPA and APOE were investigated. This was compared with the yield of Sanger sequencing between 1999 and 2016. RESULTS: A total of 227 out of the 1528 referred patients (14.9%) were heterozygous carriers of a pathogenic variant in LDLR (80.2%), APOB (14.5%) or PCSK9 (5.3%). More than 50% of patients with a Dutch Lipid Clinic Network score of 'probable' or 'definite' familial hypercholesterolemia were familial hypercholesterolemia mutation-positive; 4.8% of the familial hypercholesterolemia mutation-negative patients carried a variant in one of the minor familial hypercholesterolemia genes. The mutation detection rate has decreased over the past two decades, especially in younger patients in which it dropped from 45% in 1999 to 30% in 2018. CONCLUSIONS: A rare pathogenic variant in LDLR, APOB or PCSK9 was identified in 14.9% of suspected familial hypercholesterolemia patients and this rate has decreased in the past two decades. Stringent use of clinical criteria algorithms is warranted to increase this yield. Variants in the minor familial hypercholesterolemia genes provide a possible explanation for the familial hypercholesterolemia phenotype in a minority of patients.

Marked plaque regression in homozygous familial hypercholesterolemia.

BACKGROUND AND AIMS: Both plasma low-density lipoprotein (LDL) cholesterol levels and risk for premature cardiovascular disease are extremely elevated in patients with homozygous familial hypercholesterolemia (HoFH), despite the use of multiple cholesterol lowering treatments. Given its inborn nature, atherosclerotic plaques are commonly observed in young HoFH patients. Whether intensive lipid lowering strategies result in plaque regression in adolescent patients is unknown. METHODS: Two HoFH patients with null/null LDLR variants, who participated in the R1500-CL-1629 randomized clinical trial (NCT03399786) evaluating the LDL cholesterol lowering effect of evinacumab (a human antibody directed against ANGPTL3; 15 mg/kg intravenously once monthly), were included in this study. Patients underwent coronary computed tomography angiography (CCTA) before randomization and after 6 months of treatment. RESULTS: Both patient A (aged 12) and B (aged 16) were treated with a statin, ezetimibe and weekly apheresis. Evinacumab decreased mean pre-apheresis LDL cholesterol levels from 5.51 ± 0.75 and 5.07 ± 1.45 mmol/l to 2.48 ± 0.31 and 2.20 ± 0.13 mmol/l and post-apheresis LDL levels from 1.45 ± 0.26 and 1.37 ± 39 mmol/l to 0.80 ± 0.16 and 0.78 ± 0.13 mmol/l in patient A and B, respectively. Total plaque volumes were reduced by 76% and 85% after 6 months of evinacumab treatment in patient A and B, respectively. CONCLUSIONS: We describe two severely affected young HoFH patients in whom profound plaque reduction was observed with CCTA after intensive lipid lowering therapy with statins, ezetimibe, LDL apheresis, and evinacumab. This shows that atherosclerotic plaques possess the ability to regress at young age, even in HoFH patients.