Lipidomic profiling in patients with familial hypercholesterolemia: Abnormalities in glycerolipids and oxysterols

OBJECTIVES AND AIM

This study aimed to identify precise biomarkers and develop targeted therapeutic strategies for preventing premature atherosclerotic cardiovascular disease in patients with familial hypercholesterolemia (FH) by investigating the quantitative and qualitative abnormalities in the metabolic network of lipids in these patients using an advanced lipidomics platform.

DESIGN & METHODS

The study population comprised 18 homozygous (HoFH), 18 heterozygous (HeFH) FH patients, and 20 healthy controls. Cholesterol oxidation products (oxysterol, COPs) and main lipid classes were determined using gas chromatography-mass spectrometry. Results were expressed as percentages of total fat matter for lipid classes and percentages of total COPs for oxysterols. The principal component analysis (PCA) was also carried out, to highlight the correlation between studied parameters and groups investigated.

RESULTS

Patients (both HoFH and HeFH) showed lower content of free fatty acids (FFAs) and greater values of triacylglycerols (TAGs) in comparison to controls. HoFH showed lower monoacylglycerols (P<0.01) and higher free cholesterol (FC) (P<0.05) when compared to HeFH and controls. The total content of COPs ranged from 1.96 to 4.25 mg/dL, from 2.27 to 4.05 mg/dL, and from 0.79 to 4.12 mg/dL in healthy controls, HoFH and HeFH groups, respectively, with no significant differences between patients and controls. In general, the 7α-hydroxycholesterol (7α-HC) was greater than other COPs. However, no significant differences were found between the three studied groups. Moreover, an opposite trend was observed between 7α-HC and 7-ketocholesterol (7-KC). Additionally, when PCA was carried out, the first two PCs explained 92.13 % of the total variance, of which the PC1 describes 53.94 % of variance mainly correlated to TAGs, diacylglycerols (DAGs), and 7-KC. On the other hand, the PC2 was correlated primarily for FFAs, FC and esterified sterols (E-STE).

CONCLUSIONS

In conclusion, abnormal levels of TAGs, DAGs and 7-KC were associated with HeFH while HoFH was associated with the abnormal amount of E-STE.

Advances in familial hypercholesterolemia

Familial hypercholesterolemia (FH), a semi-dominant genetic disease affecting more than 25 million people worldwide, is associated with severe hypercholesterolemia and premature atherosclerotic cardiovascular disease. Over the last decade, advances in data analysis, screening, diagnosis and cardiovascular risk stratification has significantly improved our ability to deliver precision medicine for these patients. Furthermore, recent updates on guideline recommendations and new therapeutic approaches have also proven to be highly beneficial. It is anticipated that both ongoing and upcoming clinical trials will offer further insights for the care and treatment of FH patients.

Familial hypercholesterolemia

Familial hypercholesterolemia is a common genetic disorder of autosomal inheritance associated with elevated LDL-cholesterol. It is estimated to affect 1:250 individuals in general population roughly estimated to be 5 million in India. The prevalence of FH is higher in young CAD patients (<55 years in men; <60 years in women). FH is underdiagnosed and undertreated. Screening during childhood and Cascade screening of family members of known FH patients is of utmost importance in order to prevent the burden of CAD. Early identification of FH patients and early initiation of the lifelong lipid lowering therapy is the most effective strategy for managing FH. FH management includes pharmaceutical agents (statins and non statin drugs) and lifestyle modification. Inspite of maximum dose of statin with or without Ezetimibe, if target levels of LDL-C are not achieved, Bempedoic acid, proprotein convertase subtilisin/kexin type 9 (PCSK9) Inhibitors/Inclisiran can be added.

First clinical experiences with inclisiran in a real-world setting

BACKGROUND AND OBJECTIVE

Inclisiran is the first-in-class small interfering RNA (siRNA) proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitor. In clinical trials inclisiran showed effective and sustained low-density lipoprotein cholesterol (LDL-C) reduction of ± 50 %. As data in clinical setting are scarce, we aim to investigate the efficacy and safety in clinical practice.

METHODS

We describe a registry of consecutive patients who started with inclisiran at a lipid clinic of a university hospital. Patients were eligible if they fulfilled the reimbursement criteria in the Netherlands. Patients were included if they started with inclisiran as first line (group 1) or switched from PCSK9 monoclonal antibody (mAbs) to inclisiran (group 2). LDL-C levels were measured at 3 and 9 months after initiation of inclisiran. Median change of LDL-C levels was calculated on an individual and group level.

RESULTS

We analysed 65 patients (36 women), median [25th percentile; 75th percentile] age of 63 [54; 68] years. Of these, 44 patients had both a 3 month and 9 month visit. At 3 months, patients who newly started inclisiran (group 1, n = 45) showed a LDL-C decrease of 38 [-49;-33] %. Patients who used statins as co-medication (n = 15) had a higher median LDL-C decrease compared to those without statin use (n=30; 45 % vs 38 %). However, patients who switched from mAbs to inclisiran (group 2, n = 20) had an increase in LDL-C of 38 [+4; +97] %. Adverse effects associated with inclisiran were mild and consisted of mild injection site reactions. Efficacy was slightly less whereas safety results were similar at 9 months.

CONCLUSION

Our initial experience of inclisiran in a clinical setting showed less reduction in LDL-C levels compared to clinical trials but a similar safety profile. Moreover, patients who switched from PCSK9 mAbs to inclisiran generally showed an increase in LDL-C levels implying that inclisiran is less potent in LDL-C reduction compared to PCSK9 mAbs.

Generation and validation of a classification model to diagnose familial hypercholesterolaemia in adults

BACKGROUND AND AIMS

The early diagnosis of familial hypercholesterolaemia is associated with a significant reduction in cardiovascular disease (CVD) risk. While the recent use of statistical and machine learning algorithms has shown promising results in comparison with traditional clinical criteria, when applied to screening of potential FH cases in large cohorts, most studies in this field are developed using a single cohort of patients, which may hamper the application of such algorithms to other populations. In the current study, a logistic regression (LR) based algorithm was developed combining observations from three different national FH cohorts, from Portugal, Brazil and Sweden. Independent samples from these cohorts were then used to test the model, as well as an external dataset from Italy.

METHODS

The area under the receiver operating characteristics (AUROC) and precision-recall (AUPRC) curves was used to assess the discriminatory ability among the different samples. Comparisons between the LR model and Dutch Lipid Clinic Network (DLCN) clinical criteria were performed by means of McNemar tests, and by the calculation of several operating characteristics.

RESULTS

AUROC and AUPRC values were generally higher for all testing sets when compared to the training set. Compared with DLCN criteria, a significantly higher number of correctly classified observations were identified for the Brazilian (p < 0.01), Swedish (p < 0.01), and Italian testing sets (p < 0.01). Higher accuracy (Acc), G mean and F1 score values were also observed for all testing sets.

CONCLUSIONS

Compared to DLCN criteria, the LR model revealed improved ability to correctly classify observations, and was able to retain a similar number of FH cases, with less false positive retention. Generalization of the LR model was very good across all testing samples, suggesting it can be an effective screening tool if applied to different populations.

Early echocardiographic signs of cardiovascular affection in pediatric familial hypercholesterolemia

Familial hypercholesterolemia (FH) is a rare autosomal dominant genetic disorder caused by defective low-density lipoprotein (LDL) receptors or abnormal apolipoprotein B. FH raises the risk of premature atherosclerotic disease and cardiovascular death in young adults. However, cardiovascular affection in children needs to be more adequately studied. Our study aimed to evaluate the effect of hypercholesterolemia on the cardiovascular system of pediatric patients with homozygous FH using conventional and advanced echocardiographic parameters such as tissue Doppler imaging (TDI) and 2-dimensional speckle-tracking echocardiography (2D-STE). This case-control study matched 25 healthy children with 21 patients with homozygous FH. Both groups had conventional echocardiography, TDI, and 2D-STE. Myocardial velocities of the left and right ventricles, left ventricular strain, and aortic stiffness parameters were measured. The FH group had greater systolic blood pressure, dilated coronary arteries, and hypertrophied left ventricle (LV) compared to the control (P = 0.0001, P = 0.001, P = 0.01, respectively). The mitral E/E' ratio was higher in the patient group than in the control group (P = 0.007), indicating LV diastolic dysfunction in patients. At the same time, LV systolic function evaluated by 2D-STE was comparable to that in the control group. The abdominal aorta circumferential strain and ascending aorta M-mode-derived strain were significantly lower in patients compared to those in the control (P = 0.024, P = 0.0001, respectively), indicating increased aortic stiffness in the patients' group; moreover, 85.7% of patients had mild aortic insufficiency.  Conclusion: Mild aortic insufficiency, coronary artery dilatation, left ventricular (LV) diastolic dysfunction, and increased aortic stiffness are among early cardiovascular markers in pediatric patients with homozygous FH before impaired LV systolic function. What is Known: • Familial hypercholesterolemia (FH) in adults is associated with accelerated atherosclerosis, aortic valvopathy, dilated coronary arteries, ischemic heart disease, and premature cardiovascular death. • The cardiovascular effects of FH in children require additional research. What is New: • Pediatric patients with familial hypercholesterolemia tend to have an early affection for left ventricular diastolic function before the affection for the systolic function. • The diastolic dysfunction associated with pediatric FH is correlated to the aortic stiffness and low-density lipoprotein levels.

Applications of machine learning in familial hypercholesterolemia

Familial hypercholesterolemia (FH) is a common hereditary cholesterol metabolic disease that usually leads to an increase in the level of low-density lipoprotein cholesterol in plasma and an increase in the risk of cardiovascular disease. The lack of disease screening and diagnosis often results in FH patients being unable to receive early intervention and treatment, which may mean early occurrence of cardiovascular disease. Thus, more requirements for FH identification and management have been proposed. Recently, machine learning (ML) has made great progress in the field of medicine, including many innovative applications in cardiovascular medicine. In this review, we discussed how ML can be used for FH screening, diagnosis and risk assessment based on different data sources, such as electronic health records, plasma lipid profiles and corneal radian images. In the future, research aimed at developing ML models with better performance and accuracy will continue to overcome the limitations of ML, provide better prediction, diagnosis and management tools for FH, and ultimately achieve the goal of early diagnosis and treatment of FH.

The prevalence and treatment patterns of familial hypercholesterolemia among Thai patients with premature coronary artery disease

OBJECTIVES

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder that is characterized by severe hypercholesterolemia. The prevalence of FH in Thailand has not been reported. Therefore, this study aimed to investigate the prevalence of FH and treatment patterns among Thai patients with premature coronary artery disease (pCAD).

METHODS

A total of 1,180 pCAD patients at two heart centers from northeastern and southern Thailand between October 2018 and September 2020 were enrolled. FH was diagnosed using the Dutch Lipid Clinic Network (DLCN) criteria. pCAD was diagnosed in men aged < 55 years and women aged < 60 years.

RESULTS

The prevalence of definite/probable FH, possible FH, and unlikely FH in pCAD patients was 1.36% (n = 16), 24.83% (n = 293), and 73.81% (n = 871), respectively. Definite/probable FH in pCAD patients had a significantly higher frequency of STEMI but a lower frequency of hypertension than those with unlikely FH. After discharge, most pCAD patients (95.51%) received statin therapy. Definite/probable FH patients had a higher frequency of high-intensity statin therapy than those with possible FH and unlikely FH. After follow-up for 3-6 months, approximately 54.72% of pCAD patients with DLCN scores ≥ 5 had a reduction in LDL-C > 50% from baseline.

CONCLUSIONS

The prevalence of definite/probable FH, particularly possible FH, was high among pCAD patients in this study. The early diagnosis of FH among Thai pCAD patients should be performed for the early treatment and prevention of CAD.

The Association Between Long Working Hours of Parents and Dyslipidemia in Their Children

The purpose of our study is to examine the association between children's low-density lipoprotein cholesterol (LDL-C) levels and their parents' working hours. We used data from the 2010–2018 Korea National Health and Nutrition Examination Survey in which lipid profile samples of 3,799 children were eligible. Logistic regression analyses were used with an outcome variable of the dichotomous LDL-C group and an exposure variable of the father's and mother's working hours, respectively. In logistic regression models adjusted for age, sex, household income, education level of children and parents, and working hours of the parents, mothers' working hours more than 52 h per week were significantly associated with their children's dyslipidemia [OR 2.14, 95% confidence interval (CI) 1.33–3.47] compared to working 40 h or less, whereas fathers' working hours did not show statistical significance (OR 1.08, 95% CI 0.71–1.66) in the same manner. The association was greatest for elementary school students for mothers working more than 52 h per week (OR 3.42, 95% CI 1.64–7.14) compared to those working hours 40 h per week or less. Mothers' long working hours were associated with a higher prevalence of dyslipidemia in their children. The association was strongest for elementary school students. Proper working time of parents is required for their children's health.

Comparative study on the performance of different classification algorithms, combined with pre- and post-processing techniques to handle imbalanced data, in the diagnosis of adult patients with familial hypercholesterolemia

Familial Hypercholesterolemia (FH) is an inherited disorder of cholesterol metabolism. Current criteria for FH diagnosis, like Simon Broome (SB) criteria, lead to high false positive rates. The aim of this work was to explore alternative classification procedures for FH diagnosis, based on different biological and biochemical indicators. For this purpose, logistic regression (LR), naive Bayes classifier (NB), random forest (RF) and extreme gradient boosting (XGB) algorithms were combined with Synthetic Minority Oversampling Technique (SMOTE), or threshold adjustment by maximizing Youden index (YI), and compared. Data was tested through a 10 × 10 repeated k-fold cross validation design. The LR model presented an overall better performance, as assessed by the areas under the receiver operating characteristics (AUROC) and precision-recall (AUPRC) curves, and several operating characteristics (OC), regardless of the strategy to cope with class imbalance. When adopting either data processing technique, significantly higher accuracy (Acc), G-mean and F₁ score values were found for all classification algorithms, compared to SB criteria (p < 0.01), revealing a more balanced predictive ability for both classes, and higher effectiveness in classifying FH patients. Adjustment of the cut-off values through pre or post-processing methods revealed a considerable gain in sensitivity (Sens) values (p < 0.01). Although the performance of pre and post-processing strategies was similar, SMOTE does not cause model’s parameters to loose interpretability. These results suggest a LR model combined with SMOTE can be an optimal approach to be used as a widespread screening tool.

Regulatory Non-Coding RNAs in Familial Hypercholesterolemia, Theranostic Applications

Familial hypercholesterolemia (FH) is a common monogenic disease which is associated with high serum levels of low-density lipoprotein cholesterol (LDL-C) and leads to atherosclerosis and cardiovascular disease (CVD). Early diagnosis and effective treatment strategy can significantly improve prognosis. Recently, non-coding RNAs (ncRNAs) have emerged as novel biomarkers for the diagnosis and innovative targets for therapeutics. Non-coding RNAs have essential roles in the regulation of LDL-C homeostasis, suggesting that manipulation and regulating ncRNAs could be a promising theranostic approach to ameliorate clinical complications of FH, particularly cardiovascular disease. In this review, we briefly discussed the mechanisms and pathophysiology of FH and novel therapeutic strategies for the treatment of FH. Moreover, the theranostic effects of different non-coding RNAs for the treatment and diagnosis of FH were highlighted. Finally, the advantages and disadvantages of ncRNA-based therapies vs. conventional therapies were discussed.

Dihydroflavonoids as Bioactive Components of Penthorum chinense, a Miao Ethnomedicine, against NAFLD through Bile Acid Metabolism Pathway

Penthorum chinense Pursh. is a traditional herbal medicine of Miao, and its extracts (PCPE) have been used for treatment of liver diseases in the clinic including nonalcoholic fatty liver disease (NAFLD). However, the active components and pharmacological mechanisms of PCPE for treating NAFLD remain unclear. This study aimed to explore potential mechanisms of action through network pharmacology, molecular docking combined with experimental in vitro. A total of five dihydroflavonoids (1-5) with the same parent nucleus of pinocembrin (PCB) from PCPE, were selected as bioactive ingredients and 109 potential targets related to NAFLD were obtained from public databases and literature mining. The core targets related to the bile secretion signaling were selected based on PPI network and KEGG enrichment analysis for exploring the mechanism of PCPE against NAFLD. Molecular docking results showed good interaction between the core targets in bile secretion signaling pathway and the five compounds predicted to be bioactive. With the strong binding activity to retinoid X receptor-alpha (RXRA) and farnesoid X receptor (FXR) protein, pinocembrin-7-O-β-D-glucoside (PCBG, the highest content in PCPE) and its metabolite PCB, could significantly increase the expression of RXRA, FXR and bile salt export pump (BSEP) in L02 cells, and significantly decrease the expression of cholesterol 7α-hydroxylase (CYP7A1) at mRNA and protein levels. This study provided favorable evidence for mechanism of the main dihydroflavonoids of PCPE against NAFLD, and presented a paradigm for the study of ethnomedicine.

Cardiovascular Risk and Treatment Outcomes in Severe Hypercholesterolemia: A Nationwide Cohort Study

Background

This study aimed to evaluate the cardiovascular risk and outcomes after lipid reduction in patients with severe hypercholesterolemia using a nationwide cohort.

Methods and Results

This study used the database from the National Health Insurance Service of Korea. Among individuals who underwent regular health examination and follow‐up, 2 377 918 were enrolled and categorized into 3 groups with severe hypercholesterolemia according to low‐density lipoprotein cholesterol (LDL‐C) levels, namely, ≥260, 225 to 259, and 190 to 224 mg/dL groups, and a control group (<160 mg/dL). Risks of composite cardiovascular events (myocardial infarction, coronary revascularization, and ischemic stroke) and total mortality were compared. In statin new users, the outcomes after statin use were further analyzed according to posttreatment LDL‐C levels. The prevalence of individuals with LDL‐C≥190 mg/dL was 1 of 106. Adjusted hazard ratios of composite events and total mortality (median follow‐up, 6.1 years) in the groups ranged up to 2.4 (log‐rank P<0.0001) and 2.3 (log‐rank P=0.0002), respectively, and were dependent on LDL‐C levels. The risks of each event were up to 4.1‐, 3.8‐, and 1.9‐fold higher, respectively, in these groups. The risk of composite events (median follow‐up, 6.2 years) was lower after lipid lowering; particularly, the risk was lowest in the group showing LDL‐C<100 mg/dL after treatment (hazard ratio, 0.56, log‐rank P=0.043).

Conclusions

Using large Korean cohort data, our study proved incrementally elevated cardiovascular risk and clinical benefit associated with LDL‐C<100 mg/dL in individuals with severe hypercholesterolemia. These results support aggressive lipid lowering and provide evidence for the LDL‐C target in this population.

Hematological Inflammatory Markers in Patients with Clinically Confirmed Familial Hypercholesterolemia

Background and Aims. Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder of lipid metabolism which leads to premature cardiovascular diseases. In patients with FH, blood inflammatory markers may be disrupted; however, its extent is unclear. In this study, we aimed to evaluate the NLR (neutrophil to lymphocyte ratio), PLR (platelet count to lymphocyte count ratio), MPV (mean platelet volume), RPR (red blood cell distribution width to platelet count ratio), WBC (white blood cell), and PDW (platelet distribution width and platelet count). Methods. The patients were selected from laboratories due to high cholesterol level and who had history of premature cardiovascular disease. The Dutch Lipid Clinic Network (DLCN) criteria are used for the detection of FH. Controls had a history of hyperlipidemia, and both groups could be on pharmacotherapy or not. All the biochemical markers were evaluated using appreciate methods. Statistical analysis was done using STATA 14. Results. The study group consisted of 1074 patients with FH and 473 control cases. Of the CBC inflammatory markers, only PLR was significantly ( $p\text{value}=0.003$ ) higher in FH patients ( $7.96\pm 10.08$ ) compared to non-FH ( $6.45\pm 2.44$ ). In FH patients, the PLR was significantly higher in probable/definite FH group ( $9.70\pm 14.06$ ) compared to possible FH ( $7.36\pm 8.23$ ) ( $p\text{value}<0.001$ ). Linear regression analysis showed that only RLR was independently associated with total cholesterol ( $b=0.000$ , $p=0.13$ ). Conclusions. Our results may show the importance of high cholesterol on platelet activity and highlight the use of lipid lowering drugs in patients with hyperlipidemia.

Comorbidities with Familial Hypercholesterolemia (FH): A Systematic Review

Familial hypercholesterolemia (FH) is linked to high levels of low-density lipoprotein cholesterol (LDL-C), atherosclerotic, and aortic stenosis to a lesser extent. We looked at the incidence of prevalent comorbid disorders other than cardiovascular disease (CVD), such as diabetes, chronic kidney disease (CKD), hypertension, and cancer in heterozygous FH (HeFH) patients. PubMed, Web of Science, and Google Scholar were searched systematically for studies reporting comorbidities in FH patients. Finally, 23 studies were included after excluding duplicates, papers with unrelated titles, reviews, abstracts, and papers with not sufficient data. Results showed that among the comorbidities that have been studied; FH patients had a greater prevalence of CKD. In terms of diabetes, the data are inconsistent, with some research indicating a higher prevalence of diabetes in FH patients and mostly indicating the opposite. Polymorphism study showed that hypertension has been linked to FH; however, the prevalence of the hypertensive subjects varies among FH groups. In comparison to the general population, cancer was found to have a lower or similar prevalence in FH patients. More research is needed in this area due to the variability of the results of the relationship between diabetes and FH and the small number of studies on cancer. In conclusion only CKD can be considered as an important and prevalent comorbidity in FH population after CVDs.

Role of an automated screening tool for familial hypercholesterolemia in patients with premature coronary artery disease

Background and aims

To validate an automated screening tool for patients with premature coronary artery disease (CAD) and high total cholesterol or LDL-C levels and assess if it would provide clinicians with additional support in identifying patients with Familial Hypercholesterolemia (FH).

Methods

An IT-based automated screening tool based on coronary angiography data recorded in the KARDIO registry and laboratory values was validated among patients undergone coronary angiography in the Heart Hospital at Tampere University Hospital between 2007 and 2017 fulfilling the criteria of premature CAD (men <55 years and women <60 years) and history of high total cholesterol (>8 mmol/l) or LDL-cholesterol (>5 mmol/l) levels. Electronic health records were retrospectively analyzed to determine if these patients had been diagnosed with FH based on clinical features and whether genetic testing had been conducted.

Results

The automated screening tool identified 0.7% (211/28295) of all patients undergone coronary angiography and revealed history of high cholesterol in 8% (211/2678) of patients with premature CAD during the study period. Fifty-one percent (107/211) of these patients fulfilled the clinical criteria for probable/definite FH based on the Dutch Lipid Clinic Network (DLCN) criteria.None of the patients had been diagnosed with FH based on clinical criteria before or after diagnosis of CAD. Thirteen percent of patients (n = 14) with probable/definite FH had been tested for genetic mutations of FH before or after CAD, five (36%) of them having a pathogenic FH variant. Two patients were referred to cascade screening.

Conclusions

FH was underdiagnosed among the population studied. An automated screening tool in cardiac care could provide additional support for clinicians in diagnosing patients potentially having FH.

Impact of Severe Hypercholesterolemia on Cardiovascular Risk in Individuals With or Without Diabetes Mellitus

Objective

The aim of the current study was to investigate whether the impact of low-density lipoprotein-cholesterol (LDL-C) levels on cardiovascular risk is different between individuals with severe hypercholesterolemia and diabetes mellitus (DM) and those without DM.

Methods

This study used the database of a National Health Insurance Service cohort of Korea. Among individuals who underwent health check-up, 2,261,332 were included and categorized into 3 groups with severe hypercholesterolemia, >260, 225–259, and 190–224 mg/dL groups, and a control group (<160 mg/dL). Risks of composite events (myocardial infarction [MI], coronary revascularization, and ischemic stroke) and total mortality were analyzed, according to the presence of DM.

Results

Of the study population, 5.2% had DM. During median follow-up of 6.1 years, the rates of composite events (/1,000 person-year) in non-DM and DM subjects were up to 5.66 and 8.92, respectively. Adjusted hazard ratios (aHRs) of the composite events ranged up to 3.11 and 1.44 in non-DM and DM groups, respectively (p<0.0001 between LDL-C categories in both groups). Dependency of aHR on LDL-C levels was more prominent in the non-DM group. aHRs of MI and coronary revascularization showed similar tendency to the composite events. Although aHRs of ischemic stroke (p<0.0001) and total mortality (p=0.002) were different according to LDL-C categories in the non-DM group, these relations were not observed in DM group.

Conclusion

Although individuals with severe hypercholesterolemia had high cardiovascular risk when DM was present, the impact of LDL-C on the risk was attenuated in this population.

Shortcomings on genetic testing of Familial hypercholesterolemia (FH) in India: Can we collaborate to establish Indian FH registry?

Familial hypercholesterolemia (FH) is a common autosomal dominant disorder that affects ∼1 in 250–500 individuals globally. The only prevalence study in India shows FH in 15% of patients with premature CAD in North Indians. There are only 6 genetic studies in India of the total mutations, 32% are LDLR mutations, 4% are ApoB, 2% are PCSK9 mutations and the mutational spectrum for 37% is unknown. This calls for widespread genetic screening which could help identify definite FH patients.

European Atherosclerosis Society-Familial Hypercholesterolemia Studies Collaboration (EAS- FHSC) has taken an initiative to develop a worldwide registry of FH. India is also a part of the collaboration and 3 groups from Mumbai, Delhi and Chennai are actively contributing to this registry. We believe this review might help to understand the Indian scenario of FH and investigators across India can contribute in managing FH in India and further help in the detection, diagnosis and treatment.

Awareness, diagnosis and treatment of heterozygous familial hypercholesterolemia (HeFH) - Results of a US national survey

BACKGROUND

HeFH is a common inherited disorder that leads to markedly elevated LDL-cholesterol from birth and premature cardiovascular disease. HeFH is frequently underdiagnosed and undertreated.

OBJECTIVE

To compare how well primary care physicians and cardiologists recognize and treat HeFH.

METHODS

The National Lipid Association surveyed 500 primary care physicians and 500 cardiologists in the US who have patients with baseline LDL-cholesterol ≥ 190 mg/dL. The survey was conducted between August 29 and September 30, 2019.

RESULTS

For a hypothetical case of HeFH, 57% of cardiologists versus 43% of primary care physicians made the correct diagnosis (P<0.001). Among respondents, 21% of cardiologists versus 29% of primary care physicians have never made a diagnosis of HeFH in a patient with an LDL-cholesterol ≥ 190 mg/dL (P<0.004). Only 7% of cardiologists versus 5% of primary care physicians would refer to a lipid specialist (P=0.05). For additional LDL-cholesterol lowering after statins, 58% of cardiologists versus 48% of primary care physicians would prescribe a PCSK9 inhibitor (P=0.004); however, 30% of cardiologists versus 53% of primary care physicians have never prescribed a PSCK9 inhibitor in an HeFH patient (P<0.001).

CONCLUSION

Although cardiologists compared to primary care physicians are somewhat more likely to recognize and treat HeFH patients according to guidelines, both physician specialties do not adequately recognize or treat HeFH. There is a need for more education and training in recognizing and treating HeFH, greater access to lipid specialists, and fewer barriers for PCSK9 inhibitor use.

Familial Hypercholesterolemia in Patients with Acute Coronary Syndrome: Genetic Insights from EXPLORE-J

Aim: Genetic testing can provide a definitive diagnosis of familial hypercholesterolemia (FH). However, accessibility of genetic testing may be limited in certain countries where it is not considered “standard of care,” including Japan. In addition, mutations responsible for FH cannot be identified in approximately 30% of patients.

Methods: EXPLORE-J is a multicenter, prospective, observational study of patients presenting with acute coronary syndrome (ACS). The genetic data were analyzed and adjudicated as pathogenic, indeterminate, or nondetectable pathogenic variant.

Results: Of 1,944 patients, 431 underwent genetic screening. Overall, most patients had nonpathogenic variants ofLDLR,LDLRAP1, orPCSK9 (n=396, 91.9%). Of the 25 (5.8%) patients with pathogenic variants, variants of theLDLR gene and thePCSK9 gene were seen in 10 and 15 patients, respectively. Indeterminate variants were observed in 10 (2.3%) patients. Of the 431 patients, eight (1.9%) met the criteria for a diagnosis of FH using the Japanese Atherosclerosis Society (JAS) 2017 guidelines. When genetic data were incorporated, 33 (7.7%) patients met the JAS guidelines. No patients with FH pathogenic variants satisfied the JAS clinical criteria for a diagnosis of FH.

Conclusions: The results revealed a higher prevalence of genetic mutations of FH among Japanese patients with ACS and a low sensitivity of the FH diagnostic criteria of the JAS 2017 guidelines. These findings highlight the difficulties of FH diagnosis in patients with ACS in the acute phase and suggest the importance of genetic testing and family history.

Substantially Elevated Atherosclerotic Risks in Japanese Severe Familial Hypercholesterolemia Defined by the International Atherosclerosis Society

BACKGROUND

The International Atherosclerosis Society (IAS) has proposed "severe familial hypercholesterolemia" (FH) as a phenotype with the highest cardiovascular risk. However, whether this criteria could appropriately stratify a high-risk Japanese patient with FH remains unknown.

OBJECTIVES

This study sought to characterize atherosclerotic cardiovascular diseases in IAS-defined Japanese subjects with severe FH.

METHODS

This study analyzed 380 clinically diagnosed subjects with heterozygous FH without any history of atherosclerotic cardiovascular diseases. Severe FH was defined as untreated low-density lipoprotein cholesterol >400 mg/dL, >310 mg/dL plus 1 high-risk feature, or >190 mg/dL plus 2 high-risk features according to IAS-proposed statement. The occurrence of first and subsequent composite outcomes (cardiac [cardiac death + coronary artery disease + coronary revascularization] and noncardiac events [stroke + peripheral artery disease] was compared between subjects with severe (n = 135) and non-severe (n = 227) FH.

RESULTS

Severe FH was identified in 40.3% of study population. They had higher low-density lipoprotein cholesterol (P < 0.001) and lipoprotein(a) (P = 0.03) levels. Moreover, they more frequently received high-intensity statin (P < 0.001), PCSK9 inhibitor (P < 0.001), and lipoprotein apheresis (P = 0.01) than nonsevere FH subjects did, which resulted in a lower on-treatment low-density lipoprotein cholesterol level of subjects with severe FH (113 ± 47.2 vs 130 ± 53.9 mg/dL; P = 0.007). However, during the 7.4-year observational period, subjects with severe FH exhibited a 9.3-, 15.4-, and 5.9-fold greater risk for first composite (P < 0.001), cardiac (P < 0.001), and noncardiac outcomes (P = 0.02), respectively. Multivariate Cox proportional hazard model consistently revealed the 7.8- and 7.9-fold elevated risks of first (P < 0.001) and of subsequent (P < 0.001) composite outcomes in subjects with severe FH.

CONCLUSIONS

Japanese subjects with severe FH present profound risks of both first and subsequent atherosclerotic cardiovascular diseases in the primary prevention settings. These findings support the clinical applicability of IAS-defined severe FH in Japanese patients, which identifies those who require further stringent antiatherosclerotic management.

Familial hypercholesterolaemia: Experience of a tertiary paediatric lipid clinic

AIM

To review the experience of a dedicated paediatric multidisciplinary lipid clinic in the management of familial hypercholesterolaemia (FH) by studying the demographics, clinical presentations as well as statin therapy and outcomes.

METHODS

Retrospective database review of all patients under 18 years old seen in the lipid clinic at an Australian tertiary paediatric hospital between April 1999 and August 2017. Outcome measures collected included patient demographics, family history, lipid profile, age at treatment commencement, treatment outcomes and complications.

RESULTS

One hundred and eight patients (53 males) were seen in the lipid clinic. Eighty-five had low-density lipoprotein cholesterol (LDL-C) levels at or above the 75th percentile for sex prior to treatment. Of these, 75 had a first-degree relative with hypercholesterolaemia and/or early cardiac death. Four patients had clinical manifestations. Thirty-two patients (14 males) were started on statin therapy for likely FH. LDL-C levels reduced by 2.4 mmol/L (1.4 to 2.7) in boys and 1.9 mmol/L (0.8 to 2.8) in girls at 12 month follow-up. Five patients reported side effects requiring adjustment in therapy. Main reasons for not starting statin therapy in eligible patients were parental refusal and/or lost to follow up (77%).

CONCLUSION

A dedicated multidisciplinary lipid clinic is helpful for streamlining and monitoring management of paediatric FH. Clinical manifestations of FH are rare in children and may represent more severe form of FH or other lipid disorder. Statin therapy is efficacious and well tolerated but current recommended targets of treatment are difficult to attain. Greater awareness and coordinated services are required to overcome poor family engagement.

Successful Genetic Screening and Creating Awareness of Familial Hypercholesterolemia and Other Heritable Dyslipidemias in the Netherlands

The genetic screening program for familial hypercholesterolemia (FH) in the Netherlands, which was embraced by the Dutch Ministry of Health from 1994 to 2014, has led to twenty years of identification of at least 1500 FH cases per year. Although funding by the government was terminated in 2014, the approach had proven its effectiveness and had built the foundation for the development of more sophisticated diagnostic tools, clinical collaborations, and new molecular-based treatments for FH patients. As such, the community was driven to continue the program, insurance companies were convinced to collaborate, and multiple approaches were launched to find new index cases with FH. Additionally, the screening was extended, now also including other heritable dyslipidemias. For this purpose, a diagnostic next-generation sequencing (NGS) panel was developed, which not only comprised the culprit LDLR, APOB, and PCSK9 genes, but also 24 other genes that are causally associated with genetic dyslipidemias. Moreover, the NGS technique enabled further optimization by including pharmacogenomic genes in the panel. Using such a panel, more patients that are prone to cardiovascular diseases are being identified nowadays and receive more personalized treatment. Moreover, the NGS output teaches us more and more about the dyslipidemic landscape that is less straightforward than we originally thought. Still, continuous progress is being made that underlines the strength of genetics in dyslipidemia, such as discovery of alternative genomic pathogenic mechanisms of disease development and polygenic contribution.

The Added Value of Coronary Calcium Score in Predicting Cardiovascular Events in Familial Hypercholesterolemia

OBJECTIVES

This study aimed at investigating the additional contribution of coronary artery calcium (CAC) score to SAFEHEART (Spanish Familial Hypercholesterolemia Cohort Study) risk equation (SAFEHEART-RE) for cardiovascular risk prediction in heterozygous familial hypercholesterolemia (HeFH).

BACKGROUND

Common cardiovascular risk equations are imprecise for HeFH. Because of the high phenotype variability of HeFH, CAC score could help to better stratify the risk of atherosclerotic cardiovascular disease (ASCVD).

METHODS

REFERCHOL (French Registry of Familial Hypercholesterolemia) and SAFEHEART are 2 ongoing national registries on HeFH. We analyzed data from primary prevention HeFH patients undergoing CAC quantification. We used probability-weighted Cox proportional hazards models to estimate HRs. Area under the receiver-operating characteristic curve (AUC) and net reclassification improvement (NRI) were used to compare the incremental contribution of CAC score when added to the SAFEHEART-RE for ASCVD prediction. ASCVD was defined as coronary heart disease, stroke or transient ischemic attack, peripheral artery disease, resuscitated sudden death, and cardiovascular death.

RESULTS

We included 1,624 patients (mean age: 48.5 ± 12.8 years; men: 45.7%) from both registries. After a median follow-up of 2.7 years (interquartile range: 0.4-5.0), ASCVD occurred in 81 subjects. The presence of a CAC score of >100 was associated with an HR of 32.05 (95% CI: 10.08-101.94) of developing ASCVD as compared to a CAC score of 0. Receiving-operating curve analysis showed a good performance of CAC score alone in ASCVD prediction (AUC: 0.860 [95% CI: 0.853-0.869]). The addition of log(CAC + 1) to SAFEHEART-RE resulted in a significantly improved prediction of ASCVD (AUC: 0.884 [95% CI: 0.871-0.894] for SAFEHEART-RE + log(CAC + 1) vs AUC: 0.793 [95% CI: 0.779-0.818] for SAFEHEART-RE; P < 0.001). These results were confirmed also when considering only hard cardiovascular endpoints. The addition of CAC score was associated with an estimated overall net reclassification improvement of 45.4%.

CONCLUSIONS

CAC score proved its use in improving cardiovascular risk stratification and ASCVD prediction in statin-treated HeFH.

A comprehensive account of insulin and LDL receptor activity over the years: A highlight on their signaling and functional role

Insulin receptor (IR) was discovered in 1970. Shortcomings in IR transcribed signals were found pro-diabetic, which could also inter-relate obesity and atherosclerosis in a time-dependent manner. Low-density lipoprotein receptor (LDLR) was discovered in 1974. Later studies showed that insulin could modulate LDLR expression and activity. Repression of LDLR transcription in the absence or inactivity of insulin showed a direct cause of atherosclerosis. Leptin receptor (OB-R) was found in 1995 and its resistance became responsible for developing obesity. The three interlinked pathologies namely, diabetes, atherosclerosis, and obesity were later on marked as metabolic syndrome-X (MSX). In 2012, the IR-LDLR inter-association was identified. In 2019, the proficiency of signal transmission from this IR-LDLR receptor complex was reported. LDLR was found to mimic IR-generated signaling path when it remains bound to IR in IR-DLR interlocked state. This was the first time LDLR was found sending messages besides its LDL-clearing activity from blood vessels.

Saudi Familial Hypercholesterolemia Patients With Rare LDLR Stop Gain Variant Showed Variable Clinical Phenotype and Resistance to Multiple Drug Regimen

Familial hypercholesterolemia (FH), a well-known lipid disease caused by inherited genetic defects in cholesterol uptake and metabolism is underdiagnosed in many countries including Saudi Arabia. The present study aims to identify the molecular basis of severe clinical manifestations of FH patients from unrelated Saudi consanguineous families. Two Saudi families with multiple FH patients fulfilling the combined FH diagnostic criteria of Simon Broome Register, and the Dutch Lipid Clinic Network (DLCN) were recruited. LipidSeq, a targeted resequencing panel for monogenic dyslipidemias, was used to identify causative pathogenic mutation in these two families and in 92 unrelated FH cases. Twelve FH patients from two unrelated families were sharing a very rare, pathogenic and founder LDLR stop gain mutation i.e., c.2027delG (p.Gly676Alafs^*33) in both the homozygous or heterozygous states, but not in unrelated patients. Based on the variant zygosity, a marked phenotypic heterogeneity in terms of LDL-C levels, clinical presentations and resistance to anti-lipid treatment regimen (ACE inhibitors, β-blockers, ezetimibe, statins) of the FH patients was observed. This loss-of-function mutation is predicted to alter the free energy dynamics of the transcribed RNA, leading to its instability. Protein structural mapping has predicted that this non-sense mutation eliminates key functional domains in LDLR, which are essential for the receptor recycling and LDL particle binding. In conclusion, by combining genetics and structural bioinformatics approaches, this study identified and characterized a very rare FH causative LDLR pathogenic variant determining both clinical presentation and resistance to anti-lipid drug treatment.

Management of Familial Hypercholesterolemia: Current Status and Future Perspectives

Familial hypercholesterolemia (FH) is the most common monogenic disorder associated with premature atherosclerotic cardiovascular disease. Early diagnosis and effective treatment can significantly improve prognosis. Recent advances in the field of lipid metabolism have shed light on the molecular defects in FH and new therapeutic options have emerged. A search of PubMed database up to March 2020 was performed for this review using the following keywords: "familial hypercholesterolemia," "diagnosis," "management," "guideline," "consensus," "genetics," "screening," "lipid lowering agents." The prevalence rate of heterozygous FH is approximately 1 in 200 to 250 and FH is underdiagnosed and undertreated in many parts of the world. Diagnostic criteria have been developed to aid the clinical diagnosis of FH. Genetic testing is now available but not widely used. Cascade screening is recommended to identify affected family members, and the benefits of early interventions are clear. Treatment strategy and target is currently based on low-density lipoprotein (LDL) cholesterol levels as the prognosis of FH largely depends on the magnitude of LDL cholesterol-lowering that can be achieved by lipid-lowering therapies. Statins with or without ezetimibe are the mainstay of treatment and are cost-effective. Addition of newer medications like PCSK9 inhibitors is able to further lower LDL cholesterol levels substantially, but the cost is high. Lipoprotein apheresis is indicated in homozygous FH or severe heterozygous FH patients with inadequate response to cholesterol-lowering therapies. In conclusion, FH is a common, treatable genetic disorder, and although our understanding of this disease has improved, many challenges still remain for its optimal management.

Maternal hypercholesterolemia exacerbates atherosclerosis lesions in female offspring through potentiating macrophage polarization toward an inflammatory M1 phenotype

Maternal hypercholesterolemia induces early onset of cardiovascular diseases in offspring; however, its underlying mechanism remains poorly understood. We hypothesized that maternal hypercholesterolemia increases offspring susceptibility to atherosclerosis in adulthood through developmental modifications of macrophages. Female apolipoprotein E (ApoE)-deficient mice were fed a Western-type diet (WD) or a control diet (CD) prior to and throughout gestation and lactation. The offspring were all fed a WD after weaning. Sixteen-week-old female offspring of WD-fed dams showed a significant increase in atherosclerotic lesions of the aorta and aortic root compared with those of CD-fed dams. This effect was associated with increased macrophage accumulation within lesions, macrophage inflammation and an increase in circulating Ly6C^high monocyte and F4/80 macrophage counts. We further evidenced that in utero WD exposure promoted macrophage polarization toward the M1 phenotype by elevating M1 markers (Cd86, Inos/Nos2) without affecting M2 markers (Cd206, Arg1). Proinflammatory cytokine synthesis was also enhanced in response to LPS. Finally, maternal WD intake strongly inhibited the macrophage expression of Pparg and Lxra, which was associated with aberrant DNA methylation of Lxra promoter. Our findings demonstrate that maternal hypercholesterolemia exacerbates atherosclerosis, in part by altering the epigenetic state of the macrophage genome of the offspring, imprinting gene expression, and changing macrophage polarization, which ultimately contributes to plaque macrophage burden.

Hsa-miRNA-23a-3p promotes atherogenesis in a novel mouse model of atherosclerosis

Of the known regulators of atherosclerosis, miRNAs have been demonstrated to play critical roles in lipoprotein homeostasis and plaque formation. Here, we generated a novel animal model of atherosclerosis by knocking in LDLRW483X in C57BL/6 mice, as the W483X mutation in LDLR is considered the most common newly identified pathogenic mutation in Chinese familial hypercholesterolemia (FH) individuals. Using the new in vivo mouse model combined with a well-established atherosclerotic in vitro human cell model, we identified a novel atherosclerosis-related miRNA, miR-23a-3p, by microarray analysis of mouse aortic tissue specimens and human aortic endothelial cells (HAECs). miR-23a-3p was consistently downregulated in both models, which was confirmed by qPCR. Bioinformatics analysis and further validation experiments revealed that the TNFα-induced protein 3 (TNFAIP3) gene was the key target of miR-23a-3p. The miR-23a-3p-related functional pathways were then analyzed in HAECs. Collectively, the present results suggest that miR-23a-3p regulates inflammatory and apoptotic pathways in atherogenesis by targeting TNFAIP3 through the NF-κB and p38/MAPK signaling pathways.

Single-Strand DNA-Like Oligonucleotide Aptamer Against Proprotein Convertase Subtilisin/Kexin 9 Using CE-SELEX: PCSK9 Targeting Selection

BACKGROUND

Proprotein convertase subtilisin/kexin 9 (PCSK9) serves a key regulatory function in the metabolism of low-density lipoprotein (LDL)-cholesterol (LDL-C) through interaction with the LDL receptor (LDLR) followed by its destruction that results in the elevation of the plasma levels of LDL-C. The aims of the present study were to separate and select a number of single-stranded DNA (ssDNA) aptamers against PCSK9 from a library pool (n > 10¹²) followed by their characterization.

METHODS

The aptamers obtained from the DNA-PCSK9 complexes which presented the highest affinity against PCSK9 were separated and selected using capillary electrophoresis evolution of ligands by exponential enrichment (CE-SELEX). The selected aptamers were amplified and cloned into a T/A vector. The plasmids from the positive clones were extracted and sequenced. The Mfold web server was used to predict the secondary structure of the aptamers.

RESULTS

Following three rounds of CE-SELEX, the identified anti-PCSK9 ssDNA aptamers, namely aptamer 1 (AP-1) and aptamer 2 (AP-2), presented half maximal inhibitory concentrations of 325 and 327 nM, lowest dissociation constants of 294 and 323 nM, and most negative Gibbs free energy values of - 9.17 and - 8.28 kcal/mol, respectively.

CONCLUSION

The results indicated that the selected aptamers (AP-1 and AP-2) induced potent inhibitory effects against PCSK9. Further in vivo studies demand to find out AP-1 and AP-2 aptamers as suitable candidates, instead of antibodies, for using in therapeutic purposes in patients with hypercholesterolemia and cardiovascular disease.

Calcified Aortic Valve Disease in Patients With Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is a rare autosomal gene deficiency disease with increased low-density lipoprotein cholesterol, xanthoma, and premature coronary heart disease. Calcified aortic valve disease (CAVD) is prevalent in FH patients, resulting in adverse events and heavy health care burden. Aortic valve calcification is currently considered an active biological process, which shares several common risk factors with atherosclerosis, including aging, hypertension, dyslipidemia, and so on. Unfortunately, the pathogenesis and therapy of CAVD in FH are still controversial. There is no pharmacological intervention recommended to delay the development of CAVD in FH, and the only effective treatment for severe CAVD is aortic valve replacement. In this review, we summarize the detailed description of the pathophysiology, molecular mechanism, risk factors, and treatment of CAVD in FH patients.

Novel PCSK9 (Proprotein Convertase Subtilisin Kexin Type 9) Variants in Patients With Familial Hypercholesterolemia From Cape Town

OBJECTIVE

Familial hypercholesterolemia (FH) is characterized by elevated low-density lipoprotein-cholesterol and markedly increased cardiovascular risk. In patients with a genetic diagnosis, low-density lipoprotein receptor (LDLR) mutations account for >90% of cases, apolipoprotein B (APOB) mutations for ≈5% of cases, while proprotein convertase subtilisin kexin type 9 (PCSK9) gain of function mutations are rare (<1% of cases). We aimed to evaluate the functional impact of several novel PCSK9 variants in a cohort of patients with FH by genetic cascade screening and in vitro functionality assays. Approach and Results: Patients with clinically diagnosed FH underwent genetic analysis of LDLR, and if negative, sequential testing of APOB and PCSK9. We analyzed cosegregation of hypercholesterolemia with novel PCSK9 variants. Gain of function status was determined by in silico analyses and validated by in vitro functionality assays. Among 1055 persons with clinical FH, we identified nonsynonymous PCSK9 variants in 27 (2.6%) patients and 7 of these carried one of the 4 previously reported gain of function variants. In the remaining 20 patients with FH, we identified 7 novel PCSK9 variants. The G516V variant (c.1547G>T) was found in 5 index patients and cascade screening identified 15 additional carriers. Low-density lipoprotein-cholesterol levels were higher in these 15 carriers compared with the 27 noncarriers (236±73 versus 124±35 mg/dL; P<0.001). In vitro studies demonstrated the pathogenicity of the G516V variant.

CONCLUSIONS

In our study, 1.14% of cases with clinical FH were clearly attributable to pathogenic variants in PCSK9. Pathogenicity is established beyond doubt for the G516V variant.

Awareness, treatment rates, and compliance to treatment in patients with serum LDL cholesterol higher than 250 mg/dL, and possible, probable, or definite familial hypercholesterolemia

PURPOSE

Familial hypercholesterolemia (FH) is a genetic disease characterized by increased levels of low-density lipoprotein cholesterol (LDL-C). It is underdiagnosed and undertreated despite relatively high prevalance and significant association with increased mortality. We aimed to determine treatment status and compliance in patients with LDL-C ≥ 250 mg/dL and FH.

DESIGN

Patients older than 18 years old and have a serum LDL-C ≥ 250 mg/dL between January 2010 to December 2016 were identified from the hospital database. A phone survey was performed. Demographic features, smoking status, alcohol use, exercise, cardiovascular disease (CVD), use of medication for dyslipidemia, and CVD and high cholesterol levels in the family were questioned. Dutch Lipid Clinical Network Criteria was used to classify patients. The study was registered to Clinicaltrials.gov in July 2020 (NCT04494464).

RESULTS

1365 patients with a LDL-C ≥ 250 mg/dL were identified. Patients that could not be reached and who refused to interview were excluded and the data of 367 patients were analyzed. There were 248 (67.6%) female and 119 (32.4%) male patients and mean age was 50.52 ± 11.66. LDL-C was ≥330 mg/dL in 50 (13.6%) and 250-329 mg/dL in 317 (86.4%) patients. Forty (10.9%) patients were classified as definite, 181 (49.3%) as probable and 146 (39.8%) as possible FH. 213 (58.0%) patients were not receiving lipid-lowering treatment, and 162 (76.1%) stated that medication was never recommended previously, 30 (14.1%) had stopped medication him/herself and 21 (9.8%) had stopped medication with the advice of the physician. Among patients with definite/probable FH, 84 (38.0%) had CVD and the rate of lipid-lowering drug use in these patients was 58.3%.

CONCLUSION

A significant proportion of patients with LDL-C ≥ 250 mg/dL were not taking lipid-lowering drugs. Similar with many other studies, diagnosis, and treatment rates of FH patients were very low in our study. Further national studies are required to increase awareness of the disease in both physicians and patients.

PCSK9 Variants in Familial Hypercholesterolemia: A Comprehensive Synopsis

Autosomal dominant familial hypercholesterolemia (FH) affects approximately 1/250, individuals and potentially leads to elevated blood cholesterol and a significantly increased risk of atherosclerosis. Along with improvements in detection and the increased early diagnosis and treatment, the serious burden of FH on families and society has become increasingly apparent. Since FH is strongly associated with proprotein convertase subtilisin/kexin type 9 (PCSK9), increasing numbers of studies have focused on finding effective diagnostic and therapeutic methods based on PCSK9. At present, as PCSK9 is one of the main pathogenic FH genes, its contribution to FH deserves more explorative research.

Investigation of the underlying genes and mechanism of familial hypercholesterolemia through bioinformatics analysis

Background

Familial hypercholesterolemia (FH) is one of the commonest inherited metabolic disorders. Abnormally high level of low-density lipoprotein cholesterol (LDL-C) in blood leads to premature atherosclerosis onset and a high risk of cardiovascular disease (CVD). However, the specific mechanisms of the progression process are still unclear. Our study aimed to investigate the potential differently expressed genes (DEGs) and mechanism of FH using various bioinformatic tools.

Methods

GSE13985 and GSE6054 were downloaded from the Gene Expression Omnibus (GEO) database for bioinformatic analysis in this study. First, limma package of R was used to identify DEGs between blood samples of patients with FH and those from healthy individuals. Then, the functional annotation of DEGs was carried out by Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and Gene Ontology (GO) analysis. Based on Search Tool for the Retrieval of Interacting Genes (STRING) tool, we constructed the Protein-Protein Interactions (PPIs) network among DEGs and mined the core genes as well.

Results

A total of 102 communal DEGs (49 up-regulated and 53 down-regulated) are identified in FH samples compared with control samples. The functional changes of DEGs are mainly associated with the focal adhere and glucagon signaling pathway. Ten genes (ITGAL, TLN1, POLR2A, CD69, GZMA, VASP, HNRNPUL1, SF1, SRRM2, ITGAV) were identified as core genes. Bioinformatic analysis showed that the core genes are mainly enriched in numerous processes related to cell adhesion, integrin-mediated signaling pathway and cell-matrix adhesion. In the transcription factor (TF) target regulating network, 219 nodes were detected, including 214 DEGs and 5 TFs (SP1, EGR3, CREB, SEF1, HOX13). In conclusion, the DEGs and hub genes identified in this study may help us understand the potential etiology of the occurrence and development of AS.

Conclusion

Up-regulated ITGAL, TLN1, POLR2A, VASP, HNRNPUL1, SF1, SRRM2, and down-regulated CD69, GZMA and ITGAV performed important promotional effects for the formation of atherosclerotic plaques those suffering from FH. Moreover, SP1, EGR3, CREB, SEF1 and HOX13 were the potential transcription factors for DEGs and could serve as underlying targets for AS rupture prevention. These findings provide a theoretical basis for us to understand the potential etiology of the occurrence and development of AS in FH patients and we may be able to find potential diagnostic and therapeutic targets.

The Prevalence and Diagnostic Ratio of Familial Hypercholesterolemia (FH) and Proportion of Acute Coronary Syndrome in Japanese FH Patients in a Healthcare Record Database Study

Background

Familial hypercholesterolemia (FH) is a genetic disorder characterized by high levels of low-density lipoprotein cholesterol (LDL-C). Because of underdiagnosis, acute coronary syndrome (ACS) is often the first clinical manifestation of FH. In Japan, there are few reports on the prevalence and diagnostic ratios of FH and the proportion of ACS among FH patients in clinical settings.

Methods

This retrospective, observational study used anonymized data from electronic healthcare databases between April 2001 and March 2015 of patients who had ≥2 LDL-C measurements recorded after April 2009. The index date was defined as the date of the first LDL-C measurement after April 2009. The primary endpoint was the prevalence of definite or suspected FH; secondary endpoints included the proportion of FH patients hospitalized for ACS, the proportion of patients using lipid-lowering drugs (LLDs), and LDL-C levels.

Results

Of the 187,781 patients screened, 1547 had definite or suspected FH (0.8%) based on data from the entire period; 832 patients with definite (n = 299, 0.16%) or suspected FH (n = 533, 0.28%) before the index date were identified in the main analysis cohort. LLDs were used in 214 definite FH patients (71.6%) and 137 suspected FH patients (25.7%). Among definite or suspected FH patients with ACS (n = 84) and without ACS (n = 748), 32.1% and 30.1% with definite FH and 3.2% and 2.4% with suspected FH had LDL-C levels < 2.6 mmol/L (<100 mg/dL), respectively. Sixty patients (7.2%) were hospitalized due to ACS at the index date.

Conclusions

The prevalence of FH in this Japanese cohort of patients with ≥2 LDL-C measurements at hospitals was 0.8%, which is higher than that currently reported in epidemiological studies (0.2-0.5%). Patients with suspected FH, with or without ACS, had poorly controlled LDL-C levels and were undertreated. The proportion of FH patients who were hospitalized due to ACS was 7.2%.

Effects of a low-fat dietary regimen enriched with soy in children affected with heterozygous familial hypercholesterolemia

INTRODUCTION

Familial hypercholesterolemia (FH) is an inheritable, autosomal dominant disorder leading to pathologically increased levels of low-density-lipoprotein cholesterol (LDL-C). Dietary treatment remains an important tool in the management of affected children even after the decision for the initiation of pharmacotherapy is made. However, little evidence is available regarding the optimal dietary regimen for the treatment of children affected with FH.

METHODS

We present results from a randomized controlled trial in paediatric patients affected with heterozygous FH, assessing the effect of a soy-enriched fat modified diet (soy group) compared to fat modified diet (Control group) alone on LDL-C over a period of 13 weeks. Furthermore, we monitored isoflavone levels in plasma and urine as markers of adherence to the dietary treatments.

RESULTS

LDL-C decrease was statistically significantly greater in the soy group compared to the control group at week 7 (Control group 176.3 ± 27.8 mg/dl, soy group 154.7 ± 29.2 mg/dl, p = 0.038), and showed a trend towards significant at week 13 (Control group 179.9 ± 41.8 mg/dl, soy group 155.0 ± 30.2 mg/dl, p = 0.089). Relative LDL-C decrease correlated significantly with the following plasma isoflavone concentrations measured in week 7: daidzein (p < 0.004, r = 0.576) and genistein (p < 0.017, r = 0.490).

CONCLUSIONS

We provide evidence from a small randomized-controlled trial for the effectiveness and safety of a dietary treatment with soy in paediatric patients affected with heterozygous FH. The decrease in LDL-C was highly correlated with isoflavone levels, further highlighting a direct effect of soy ingestion. This study was registered under ClinicalTrials.gov Identifier No. NCT03563547.

Incorporation of genetic testing significantly increases the number of individuals diagnosed with familial hypercholesterolemia

BACKGROUND

It is estimated that less than 10% of cases of familial hypercholesterolemia (FH) in the United States have been diagnosed. Low rates of diagnosis may in part be attributable to affected patients not meeting the clinical diagnostic criteria of the Dutch Lipid Clinic Network (DLCN), Simon Broome, or US MEDPED diagnostic criteria.

OBJECTIVE

The objective of this study was to assess the utility of incorporating genetic testing into a patient's evaluation for FH.

METHODS

We retrospectively reviewed patients seen in the Advanced Lipids Disorders Clinic at Johns Hopkins Hospital between January 2015 and May 2018. Between June 2018 and December 2018, patients were consented to a prospective registry. DLCN, Simon Broome, and MEDPED criteria were applied to each patient, before and after genetic testing. Genetic testing included sequencing and deletion duplication analysis of four genes (LDLR, PCSK9, APOB, and LDLRAP1).

RESULTS

The retrospective review and prospective study identified 135 adult probands who were seen in our clinic for evaluation of heterozygous FH. Twenty-nine individuals (21%) were heterozygous for a pathogenic or likely pathogenic monogenic variant. Before genetic testing, using the DLCN criteria, 35 (26%) individuals met criteria for a definite diagnosis of FH. Thirty patients (22%) met criteria using Simon Broome, and 29 (21%) patients met criteria using US MEDPED before genetic analysis. Depending on the criteria, incorporating genetic testing identified 11-14 additional patients with FH.

CONCLUSIONS

Incorporating genetic testing diagnosed almost 50% more patients with definite FH in comparison to classification solely on clinical grounds.

Developing implementation strategies to improve uptake of guideline-recommended treatments for individuals with familial hypercholesterolemia: A protocol

BACKGROUND

Familial hypercholesterolemia (FH) affects more than one million Americans, and most individuals have not been formally diagnosed with the condition. Individuals with FH have markedly elevated serum low-density lipoprotein cholesterol (LDL-C) levels from birth that substantially increase their risk for early-onset cardiovascular (CV) events. Guideline-recommended treatments exist to lower LDL-C and reduce the risk of CV events in individuals with FH and hypercholesterolemia. This study seeks to address a significant gap in the care of individuals with FH by systematically developing an effective approach to increase the adoption of guideline-recommended treatments for FH.

METHODS

This developmental study will consist of three aims: 1) determine the barriers to and facilitators of treatment of FH; 2) develop a list of potential implementation strategies to promote the adoption of guideline-recommended treatment of individuals with FH, and 3) pilot one implementation strategy from Aim 2 in one health care system to evaluate implementation outcomes of the strategy. The Practical, Robust Implementation and Sustainability Model will guide this project, including the development of interview questions, implementation strategies, and evaluation of the implementation strategy. The implementation outcomes include: of individuals targeted by the implementation strategy, how many are impacted by it (reach), measure the change in knowledge, attitude, and behavior that is impacted by the implementation strategy (effectiveness), in settings targeted by the implementation strategy, how many adopt it (adoption), and fidelity and cost of the implementation strategy (implementation). Data sources will include electronic health records, administrative databases, surveys, and semi-structured interviews.

DISCUSSION

The inclusion of patient and organizational stakeholder experiences is a critically important step in developing efficient and effective implementation strategies. Additionally, perspectives from a variety of geographic areas and cultural perspectives should increase feasibility and fidelity of the interventional approach to improve adoption of guideline-recommended practices for FH care.

Use of PCSK9 Inhibitor in a Mexican Boy with Compound Heterozygous Familial Hypercholesterolemia: A Case Report

We report on the case of an 8-year-old Mexican male, with a 3-year-old clinical diagnosis of familial hypercholesterolemia, and the difficulties encountered in his treatment while in our care. His treatment started with a regimen consisting of ezetimibe/simvastatin, cholestyramine, and a dietary plan of 1600 calories, with a limited intake of 200 mg of cholesterol per day. Problems arose when the patient's low-density lipoprotein cholesterol (LDL) levels did not meet ideal targets, which prompted the use of LDL cholesterol apheresis (not available in Mexico) for 6 months. As a last resort, PCSK9 inhibitors were administered but the LDL levels remained in the 600 mg/dL range. AmbryGenetics conducted a genetic test employing the Sanger method. The results suggested that there were 2 different mutations for each allele of the same LDL receptor gene (c.249delTinsGG and p.(Cys109Arg)), located in exons 3 and 4, respectively. We identified compound heterozygous mutations in our index case, with him having both the p.C109R mutation (from the maternal lineage), as well as a c.249delTinsGG mutation (from the paternal lineage). The p.C109R mutation has been previously reported, not only in Mexico, but in European regions (Germany, Czech Republic, Ireland, Italy) as well. Functional studies indicated a residual enzymatic activity of 15% to 30% for heterozygotes. To date, the variant c.249delTinsGG has not been reported. This case study illustrates the fact that in Mexico there are limited options available for treatment in such a scenario. As medical professionals, we are limited by the tools at our disposal.

Behavioural cardiovascular risk factors and prevalence of diabetes in subjects with familial hypercholesterolaemia

A low prevalence of type 2 diabetes mellitus has been reported in familial hypercholesterolaemia. Whether a healthier lifestyle could explain it has not been explored. This cross-sectional study determines the prevalence of lifestyle-related cardiovascular risk factors in heterozygous familial hypercholesterolaemia (HeFH) from the Dyslipidaemia Registry of the Spanish Atherosclerosis Society and in the ENRICA study, a representative sample of the adult Spanish general population, weighted to match the age and sex distribution of the HeFH sample. A total of 2185 HeFH patients and 11,856 individuals from ENRICA were included. HeFH had lower body mass index and fewer of them were smokers than in the reference population. A model adjusted for age, sex and body mass index showed that HeFH more frequently had cardiovascular disease (odds ratio (OR) 23.98; 95% confidence interval (CI) 18.40-31.23) and hypertension (OR 1.20; 95% CI 1.07-1.35), and took anti-hypertensive medication (OR 1.36; 95% CI 1.18-1.56) and anti-diabetic medication (OR 1.25; 95% CI 1.00-1.56), but less frequently were smokers (OR 0.79; 95% CI 0.71-0.89). In a HeFH subsample (n = 513) with complete blood glucose information, those patients without cardiovascular disease showed lower prevalence of smoking and type 2 diabetes mellitus, lower body mass index and glucose, and higher diastolic blood pressure than the Spanish population. The differences in type 2 diabetes mellitus were justified mostly by the difference in body mass index. Body mass index adjustment also showed higher prevalence of hypertension and use of anti-hypertensive drugs in HeFH. In summary, HeFH patients had lower body mass index, which may contribute to explaining the lower prevalence of diabetes, and lower current smoking but higher hypertension.

LDL-Cholesterol-Lowering Therapy

The causal relation between elevated levels of LDL-C and cardiovascular disease has been largely established by experimental and clinical studies. Thus, the reduction of LDL-C levels is a major target for the prevention of cardiovascular disease. In the last decades, statins have been used as the main therapeutic approach to lower plasma cholesterol levels; however, the presence of residual lipid-related cardiovascular risk despite maximal statin therapy raised the need to develop additional lipid-lowering drugs to be used in combination with or in alternative to statins in patients intolerant to the treatment. Several new drugs have been approved which have mechanisms of action different from statins or impact on different lipoprotein classes.

Familial hypercholesterolemia and elevated lipoprotein(a): double heritable risk and new therapeutic opportunities

There is compelling evidence that the elevated plasma lipoprotein(a) [Lp(a)] levels increase the risk of atherosclerotic cardiovascular disease (ASCVD) in the general population. Like low-density lipoprotein (LDL) particles, Lp(a) particles contain cholesterol and promote atherosclerosis. In addition, Lp(a) particles contain strongly proinflammatory oxidized phospholipids and a unique apoprotein, apo(a), which promotes the growth of an arterial thrombus. At least one in 250 individuals worldwide suffer from the heterozygous form of familial hypercholesterolemia (HeFH), a condition in which LDL-cholesterol (LDL-C) is significantly elevated since birth. FH-causing mutations in the LDL receptor gene demonstrate a clear gene-dosage effect on Lp(a) plasma concentrations and elevated Lp(a) levels are present in 30-50% of patients with HeFH. The cumulative burden of two genetically determined pro-atherogenic lipoproteins, LDL and Lp(a), is a potent driver of ASCVD in HeFH patients. Statins are the cornerstone of treatment of HeFH, but they do not lower the plasma concentrations of Lp(a). Emerging therapies effectively lower Lp(a) by as much as 90% using RNA-based approaches that target the transcriptional product of the LPA gene. We are now approaching the dawn of an era, in which permanent and significant lowering of the high cholesterol burden of HeFH patients can be achieved. If outcome trials of novel Lp(a)-lowering therapies prove to be safe and cost-effective, they will provide additional risk reduction needed to effectively treat HeFH and potentially lower the CVD risk in these high-risk patients even more than currently achieved with LDL-C lowering alone.

PCSK9 Inhibition and Atherosclerosis: Current Therapeutic Option and Prospection

Low-density lipoprotein cholesterol (LDL-C) is a pivotal factor in atherosclerotic cardiovascular disease (ASCVD), the leading cause of worldwide mortality. The limitations of statin therapy require alternative treatment strategies to achieve target LDL-C level. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an important role in LDLR recycling, consequently regulating plasma cholesterol levels. Monoclonal antibodies targeting PCSK9 increased expression of LDLRs at the cell surface and therefore decreased circulating LDL-C. PCSK9 inhibitors have shown great efficacy in reducing plasma LDL-C levels, which needs to inject once or twice monthly. Though SPIRE sponsors concern the immunogenicity and terminate trials early, FOURIER and ODYSSER OUTCOME trials improved the efficacy of PCSK9 inhibitors in LDL-C reduction. Inclisiran actually is a small interfering RNA (siRNA) developed to inhibit PCSK9 messenger RNA, leading to reduced concentrations of the PCSK9 protein and thereby lower concentrations of LDL-C. Inclisiran is a latest alternative treatment to cholesterol-lowering therapeutics. Twice injections of inclisiran durably reduced LDL-C levels over 1 year. siRNA therapeutics provided a simple, novel, and less frequent approach to LDL-C reduction in phase I and II trials, which may be used either as in combination with statin therapeutics or a stand-alone therapy in the future.

The nonalcoholic fatty liver disease-like phenotype and lowered serum VLDL are associated with decreased expression and DNA hypermethylation of hepatic ApoB in male offspring of ApoE deficient mothers fed a with Western diet

Increasing evidence indicates that the intra-uterine environment has consequences for later life. However, the mechanisms of this fetal programming remain unclear. We aimed to investigate the impact of diet-induced maternal hypercholesterolemia on the predisposition of offspring to nonalcoholic fatty liver diseases (NAFLD) and metabolic diseases and its underlying mechanisms. Female apolipoprotein (Apo) E-deficient mice were fed a control diet (CD) or high fat/high cholesterol Western-type diet (WD) before and throughout pregnancy and lactation, and their offspring were weaned onto a CD postnatally. Strikingly, male offspring of WD-fed dams developed glucose intolerance and decreased peripheral insulin sensitivity and exhibited hepatic steatosis. Hepatic steatosis could be attributed, at least in part, to increased hepatic lipogenesis in E18.5 embryos and decreased serum VLDL levels in adulthood. In addition, males born to WD-fed dams had lower serum ApoB levels and hepatic ApoB gene expression compared with males born to CD-fed dams. DNA methylation analysis revealed increased methylation of CpG dinucleotides on the promoter region of the ApoB genes in the livers of male offspring of WD-fed dams. Our findings suggest that maternal WD intake can exacerbate the development of NAFLD in male offspring potentially by affecting ApoB gene expression through epigenetic alterations.