Multiparametric platform for profiling lipid trafficking in human leukocytes.

Systematic insight into cellular dysfunction can improve understanding of disease etiology, risk assessment, and patient stratification. We present a multiparametric high-content imaging platform enabling quantification of low-density lipoprotein (LDL) uptake and lipid storage in cytoplasmic droplets of primary leukocyte subpopulations. We validate this platform with samples from 65 individuals with variable blood LDL-cholesterol (LDL-c) levels, including familial hypercholesterolemia (FH) and non-FH subjects. We integrate lipid storage data into another readout parameter, lipid mobilization, measuring the efficiency with which cells deplete lipid reservoirs. Lipid mobilization correlates positively with LDL uptake and negatively with hypercholesterolemia and age, improving differentiation of individuals with normal and elevated LDL-c. Moreover, combination of cell-based readouts with a polygenic risk score for LDL-c explains hypercholesterolemia better than the genetic risk score alone. This platform provides functional insights into cellular lipid trafficking and has broad possible applications in dissecting the cellular basis of metabolic disorders.

Association between causative mutations and response to PCSK9 inhibitor therapy in subjects with familial hypercholesterolemia: A single center real-world study.

BACKGROUND AND AIMS: Familial hypercholesterolemia (FH) is an autosomal dominant disease that leads to cardiovascular (CV) disease. Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9-I) demonstrated efficacy in low-density lipoprotein cholesterol (LDL-C) reduction and in prevention of CV events. The aim of our study is to evaluate the relationship between LDL receptor (LDLR) mutations and response to PCSK9-I therapy. METHODS AND RESULTS: We evaluated total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) in consecutive patients with FH before PCSK9-I treatment and after 12 (T12w) and 36 (T36w) weeks of treatment. We evaluated LDL-C target achievement according to different mutations in LDLR. Eighty FH subjects (mean age:54 ± 13.3 years), 39 heterozygous (He) with defective LDLR gene mutations, 30 He with null mutations and 11 compound-He or homozygous (Ho) were recruited. At baseline, 69 subjects were under maximal lipid lowering therapy (MLLT) and 11 subjects had statin-intolerance. From baseline to T36w we observed an overall 51% reduction in LDL-C. We found no difference in LDL-C changes between subjects with He-defective mutation and He-null mutations both at T12w (p = 1.00) and T36w (p = 0.538). At T36w, LDL-C target was achieved in 59% of He-defective mutations subjects and in 36% of He-null mutations subgroup (p = 0.069), whereas none of compound-He/Ho-FH achieved LDL-C target. CONCLUSIONS: After 36 weeks there were no differences in response to PCSK9-I therapy between different groups of He-FH subjects. Response to PCSK9-I was significantly lower in carriers of compound-He/Ho mutations. Registration number for clinical trials: NCT04313270 extension.

Changes in carotid stiffness in patients with familial hypercholesterolemia treated with Evolocumab®: A prospective cohort study.

BACKGROUND AND AIM: Protein convertase subtilisin kexin type 9 (PCSK-9) inhibitors demonstrated efficacy in cholesterol reduction and in the prevention of cardiovascular events. We evaluated changes in lipid profile and carotid stiffness in patients with familial hypercholesterolemia during 12 weeks of treatment with a PCSK-9 inhibitor, Evolocumab®. METHODS AND RESULTS: Patients with familial hypercholesterolemia starting a treatment with Evolocumab® were included. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), small dense LDL (assessed by LDL score) and carotid stiffness were evaluated before starting treatment with Evolocumab® and during 12 weeks of treatment. Twenty-five subjects were enrolled (52% males, mean age 51.5 years). TC and LDL-C were reduced of 38% and 52%, respectively during treatment, with LDL score reduced of 46.1%. In parallel, carotid stiffness changed from 8.8 (IQR: 7.0-10.4) m/sec to 6.6 (IQR: 5.4-7.5) m/sec, corresponding to a median change of 21.4% (p < 0.001), with a significant increase in carotid distensibility (from 12.1, IQR: 8.73-19.3 kPA-1 × 10-3 at T0 to 21.8, IQR: 16.6-31.8 kPA-1 × 10-3 at T12w) corresponding to a median change of 62.8% (p < 0.001). A multivariate analysis showed that changes in LDL score were independently associated with changes in carotid stiffness (ß = 0.429, p = 0.041). CONCLUSION: Small dense LDL reduction, as assessed by LDL score, is associated with changes in carotid stiffness in patients with familial hypercholesterolemia treated with Evolocumab®.

Causative mutations and premature cardiovascular disease in patients with heterozygous familial hypercholesterolaemia.

Background Familial hypercholesterolemia is a common autosomal dominant disease, caused by mutations leading to elevated low-density lipoprotein (LDL) cholesterol and, if untreated, to premature cardiovascular disease. Methods Patients (young adults with a family history of hypercholesterolaemia or premature cardiovascular disease) with LDL cholesterol concentration ≥4.9 mmol/l, after excluding Familial Combined Hyperlipidaemia, were evaluated for causative mutations, Dutch Lipid Clinic Network score calculation and non-invasive ultrasound examination of carotid arteries. Results Of the 263 patients, 210 were heterozygotes for LDL receptor ( LDLR) mutations, four had APOB gene mutations, one PCSK9 gene mutation, while 48 had no evidence of mutations. Among 194 unrelated index cases 149 had mutations (77%). Among patients with LDLR mutations ( n = 145), there were five compound heterozygotes, 75 patients with null mutations and 65 with missense mutations. As many as 178 patients underwent a follow-up and treatment (statin ± ezetimibe), achieving a mean reduction of 49% in LDL cholesterol, with 21% of patients reaching the LDL goal of 2.6 mmol/l. In a multivariate analysis, carotid plaques, at ultrasound examination, were associated with the presence of genetic mutation ( p = 0.001), LDL cholesterol ( p < 0.001), Dutch Lipid Clinic Network score ( p < 0.001), independently of age, gender, smoking habits and systolic blood pressure. The presence of carotid plaque ( p = 0.017), LDL cholesterol ( p < 0.003), Dutch Lipid Clinic Network score ( p < 0.001) were independently associated with premature cardiovascular disease. Conclusions We identified patients with causative mutations in 82% of the cases under study. In addition to LDL cholesterol and Dutch Lipid Clinic Network score, carotid plaques in ultrasound evaluation provide direct evidence of premature vascular disease and are associated with high risk for cardiovascular events.

C-reactive protein levels are associated with paraoxonase polymorphism L55M in patients undergoing cardiac SPECT imaging.

BACKGROUND: Oxidation and inflammation are linked processes playing an important role in the development and progression of coronary artery disease (CAD). The relation between oxidation and inflammation markers with myocardial ischemia is still controversial. We assessed the association between paraoxonase (PON) polymorphisms (rs854560, rs662, rs7493) and high sensitivity C-reactive protein levels with stress-induced ischemia in patients with suspected CAD. MATERIALS AND METHODS: Patients (n = 203; 78 men; mean age 59 ± 10 years), with suspected CAD underwent on the same day stress/rest Tc-99m sestamibi cardiac single-photon emission computed tomography and venous blood samples collection, to assess PON polymorphisms, lipid profile and high sensitivity C-reactive protein levels. RESULTS: At cardiac tomography, 43 (21%) patients had stress-induced myocardial ischemia and 160 (79%) did not. At logistic regression analysis, diabetes (p < 0.005), sex (p = 0.020) and high-density lipoprotein (HDL)-cholesterol levels (p < 0.050) were independently associated with stress-induced ischemia. No differences of PON1 and PON2 genotype frequencies were observed between patients with and without stress-induced ischemia. Multiple linear regression analysis showed that LL genotype for PON1 (p < 0.03), high body mass index (BMI) values (p < 0.001) and low HDL-cholesterol levels (p < 0.05) are associated with high C-reactive protein levels independently from presence of stress-induced ischemia, age, sex, diabetes, hypertension, statin therapy, smoking and total cholesterol levels. CONCLUSIONS: The results of this study identified a weak association between the M55L polymorphism in PON1 gene and C-reactive protein levels. BMI showed a major role in the determination of C-reactive protein levels. No association between PON polymorphisms and stress-induced ischemia was found.

Polymorphisms and the expression of genes encoding enzymes involved in cardiovascular diseases.

BACKGROUND: Atherosclerosis, a multi-factorial disease, is the main determinant of cardiovascular disease (CVD) leading to high mortality and morbidity in westernized countries. Gene polymorphisms and gene expression related to the atherosclerosis process can be identified using a genome-wide approach or looking for candidate disease-causing genes. METHODS: Using genome wide strategy or candidate gene approach various genes, including paraoxonase genes, which are involved in lipid metabolism, oxidation, inflammation and coagulation, have been associated to atherosclerosis. CONCLUSION: Evaluation of gene polymorphisms, together with traditional and novel biochemical parameters, may help identify individuals at a high risk for CVD. Genetic characterization of susceptibility genes may also lead to new drugs for atherosclerosis prevention and treatment. In addition, gene expression studies can provide novel insights into the molecular mechanism of lesion development and progression.