Heterozygous familial hypercholesterolaemia in childhood: cardiovascular risk prevention

Rastreamento para Hipercolesterolemia Familiar em Pequenos Municípios: A Experiência do Programa HipercolBrasil em 11 Municípios Brasileiros

Fundamento

A hipercolesterolemia familiar (HF) é uma doença genética dominante que se caracteriza por níveis sanguíneos elevados de colesterol de lipoproteína de baixa densidade (LDL-C), e está associada à ocorrência de doença cardiovascular precoce. No Brasil, o HipercolBrasil, que é atualmente o maior programa de rastreamento em cascata para HF, já identificou mais de 2.000 indivíduos com variantes genéticas causadoras de HF. A abordagem padrão baseia-se no rastreamento em cascata de casos índices referidos, indivíduos com hipercolesterolemia e suspeita clínica de HF.

Objetivos

Realizar rastreamento direcionado de 11 pequenos municípios brasileiros com suspeita de alta prevalência de indivíduos com HF.

Métodos

A seleção dos municípios ocorreu de 3 maneiras: 1) municípios em que houve suspeita de efeito fundador (4 municípios); 2) municípios em uma região com altas taxas de infarto do miocárdio precoce, conforme descrito pelo banco de dados do Sistema Único de Saúde (2 municípios); e 3) municípios geograficamente próximos a outros municípios com alta prevalência de indivíduos com HF (5 municípios). A significância estatística foi considerada como valor p < 0,05.

Resultados

Foram incluídos 105 casos índices e 409 familiares de primeiro grau. O rendimento dessa abordagem foi de 4,67 familiares por caso índice, o qual é significativamente melhor (p < 0,0001) do que a taxa geral do HipercolBrasil (1,59). Identificamos 36 CIs com variante patogênica ou provavelmente patogênica para HF e 240 familiares de primeiro grau afetados. Conclusão: Nossos dados sugerem que, uma vez detectadas, regiões geográficas específicas justificam uma abordagem direcionada para a identificação de aglomerações de indivíduos com HF.

Predictors of cardiovascular events after one year of molecular screening for Familial hypercholesterolemia

BACKGROUND AND AIMS

This study reports the first year follow-up of individuals enrolled in Brazil's genetic cascade screening program for Familial Hypercholesterolemia (FH), Hipercol Brasil. Predictors for the occurrence of cardiovascular (CV) events in individuals screened for FH were studied.

METHODS

This is an open prospective cohort of individuals who were included in a cascade genetic screening program for FH. The first prospective follow-up was carried out one year after patients received their genetic test result. Individuals included in this study were index cases (probands) and relatives with identified (M +) or not genetic mutations (M -). Logistic regression analysis was performed to determine predictive variables for the occurrence of CV events censored at one-year of follow-up.

RESULTS

A total of 818 subjects were included, 47 first CV events were ascertained, with 14 (29.7%) being fatal. For index cases, the only factor independently associated with increased risk of CV events was the presence of corneal arcus (OR: 9.39; 95% CI: 2.46-35.82). There was an inverse association of CV events with higher HDL-cholesterol levels (OR: 0.95; 95% CI: 0.90-0.99). For M+ relatives, risk factors associated with increased CV events risk were diabetes mellitus (OR: 7.97; 95% CI: 2.07-30.66) and tobacco consumption (OR: 3.70; 95% CI: 1.09-12.50).

CONCLUSIONS

A high one-year incidence of CV events was found in this cascade-screening cohort. Predictors of events differed between index cases and relatives and can be useful for the development of preventive efforts in this highly susceptible group of individuals.

Predictors of screening for hyperlipidemia in an urban pediatric tertiary care center

INTRODUCTION

It is unknown how the conflicting recommendations of the American Academy of Pediatrics and the US Preventive Services Task Force on pediatric hyperlipidemia affect screening.

OBJECTIVES

(a) Identify clinical predictors for screening for hyperlipidemia, (b) assess the adherence to the 2008 American Academy of Pediatrics guidelines, and (c) determine the efficacy of reminder cards in increasing the adherence to the aforementioned guidelines.

METHODS

Retrospective chart review in the resident, attending, and adolescent medicine clinics during a 3-month period. Reminder cards on each patient chart outlining guidelines for lipid screening for the same clinics were inserted and prospectively assessed for adherence during the following 3 months.

RESULTS

Older age and higher body mass index increased likelihood (odds ratio = 1.2 and 12.7, respectively) for lipid screening. Reminder cards improved adherence in the resident clinic only (χ2 P = .016).

CONCLUSIONS

Age and body mass index were the most significant predictors for lipid screening. Reminder cards modestly improved adherence among resident physicians.

Management of familial hypercholesterolemia in children and young adults: consensus paper developed by a panel of lipidologists, cardiologists, paediatricians, nutritionists, gastroenterologists, general practitioners and a patient organization

Since heterozygous familial hypercholesterolemia (HeFH) is a disease that exposes the individual from birth onwards to severe hypercholesterolemia with the development of early cardiovascular disease, a clear consensus on the management of this disease in young patients is necessary. In Belgium, a panel of paediatricians, specialists in (adult) lipid management, general practitioners and representatives of the FH patient organization agreed on the following common recommendations. 1. Screening for HeFH should be performed only in children older than 2 years when HeFH has been identified or is suspected (based on a genetic test or clinical criteria) in one parent.2. The diagnostic procedure includes, as a first step, the establishment of a clear diagnosis of HeFH in one of the parents. If this precondition is satisfied, a low-density-lipoprotein cholesterol (LDL-C) levelabove 3.5 mmol/L (135 mg/dL) in the suspected child is predictive for differentiating affected from non-affected children. 3. A low saturated fat and low cholesterol diet should be started after 2 years, under the supervision of a dietician or nutritionist.4. The pharmacological treatment, using statins as first line drugs, should usually be started after 10 years if LDL-C levels remain above 5 mmol/L (190 mg/dL), or above 4 mmol/L (160 mg/dL) in the presence of a causative mutation, a family history of early cardiovascular disease or severe risk factors. The objective is to reduce LDL-C by at least 30% between 10 and 14 years and, thereafter, to reach LDL-C levels of less than 3.4 mmol/L (130 mg/dL).

CONCLUSION

The aim of this consensus statement is to achieve more consistent management in the identification and treatment of children with HeFH in Belgium.

Cascade Screening for Familial Hypercholesterolemia (FH)

Familial hypercholesterolemia (FH) is an autosomal dominant disorder characterized by abnormally high concentrations of low-density lipoprotein (LDL) cholesterol in the blood, which predisposes affected persons to premature coronary heart disease (CHD) and death. FH is one of the most common inherited disorders and the most common one known to cause premature CHD in people of European descent. The vast majority of people with FH have inherited a single mutation from one parent in either the LDL receptor (LDLR), apolipoprotein B (APOB), or proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. Despite their greatly elevated risk of coronary heart disease, most individuals with FH remain undiagnosed, untreated, or inadequately treated.

Cascade screening is a mechanism for identifying people at risk for a genetic condition by a process of systematic family tracing. The National Institute for Health and Clinical Excellence in the United Kingdom recommends cascade screening of close biological relatives of people with a clinical diagnosis of FH in order to effectively identify additional FH patients. The ultimate goal of this testing is to reduce morbidity and mortality from heart disease in persons with FH through early diagnosis and effective disease management. The goal of this article is to outline the available evidence on the clinical validity and utility of cascade screening for FH, while emphasizing the availability, usefulness, and recommendation for including DNA testing (if the disease-causing mutation has been identified).

A systematic review of bile acid sequestrant therapy in children with familial hypercholesterolemia

Familial hypercholesterolemia, which arises as a result of a mutation in the low-density lipoprotein (LDL) receptor gene, is characterized by elevated levels of low-density lipoprotein cholesterol (LDL-C), regardless of dietary and lifestyle modifications. Pharmacological therapy is often required to adequately control the elevated LDL-C levels associated with familial hypercholesterolemia. However, children with this genetic condition present many challenges for physicians, who must weigh the benefits of lipid-lowering therapy against the risks associated with the various treatment options. Furthermore, because familial hypercholesterolemia is a chronic condition, children will likely require long-term lipid-lowering therapy. As such, the potential effect of pharmacological treatment on development is of paramount importance in this population. Bile acid sequestrants represent a unique treatment option for children with familial hypercholesterolemia in that these agents are not systemically absorbed but rather exert their lipid-lowering effects via binding to bile acids within the gastrointestinal tract. A literature search was performed to identify clinical data related to the use of bile acid sequestrant therapy in children (< 18 years of age) with familial hypercholesterolemia. Studies published in English between 1990 and December 2010 that were retrieved from MEDLINE and EMBASE were included in this systematic review. In total, five clinical studies were identified that evaluated bile acid sequestrant monotherapy, whereas two studies were identified that evaluated combination therapy with a bile acid sequestrant and low-dose statin. This review summarizes the clinical data regarding the efficacy and safety of bile acid sequestrants in this specialized population.

Epicardial fat gene expression after aerobic exercise training in pigs with coronary atherosclerosis: relationship to visceral and subcutaneous fat

Epicardial adipose tissue (EAT) is contiguous with coronary arteries and myocardium and potentially may play a role in coronary atherosclerosis (CAD). Exercise is known to improve cardiovascular disease risk factors. The purpose of this study was to investigate the effect of aerobic exercise training on the expression of 18 genes, measured by RT-PCR and selected for their role in chronic inflammation, oxidative stress, and adipocyte metabolism, in peri-coronary epicardial (cEAT), peri-myocardial epicardial (mEAT), visceral abdominal (VAT), and subcutaneous (SAT) adipose tissues from a castrate male pig model of familial hypercholesterolemia with CAD. We tested the hypothesis that aerobic exercise training for 16 wk would reduce the inflammatory profile of mRNAs in both components of EAT and VAT but would have little effect on SAT. Exercise increased mEAT and total heart weights. EAT and heart weights were directly correlated. Compared with sedentary pigs matched for body weight to exercised animals, aerobic exercise training reduced the inflammatory response in mEAT but not cEAT, had no effect on inflammatory genes but preferentially decreased expression of adiponectin and other adipocyte-specific genes in VAT, and had no effect in SAT except that IL-6 mRNA went down and VEGFa mRNA went up. We conclude that 1) EAT is not homogeneous in its inflammatory response to aerobic exercise training, 2) cEAT around CAD remains proinflammatory after chronic exercise, 3) cEAT and VAT share similar inflammatory expression profiles but different metabolic mRNA responses to exercise, and 4) gene expression in SAT cannot be extrapolated to VAT and heart adipose tissues in exercise intervention studies.

Role of colesevelam in managing heterozygous familial hypercholesterolemia in adolescents and children

BACKGROUND

Colesevelam hydrochloride is a synthetic, nonsystemically absorbed polymer that functions as a bile acid sequestrant for the treatment of hypercholesterolemia. Recently, colesevelam was investigated for the treatment of heterozygous familial hypercholesterolemia (HeFH) in the pediatric/adolescent population aged 10-17 years.

OBJECTIVE

The purpose of this article is to review the disease state of HeFH in children and adolescents, review the pharmacologic mechanism of action, kinetics, and safety profile of colesevelam, analyze the results of a recent clinical trial of colesevelam in the pediatric/adolescent HeFH population, and discuss the role of colesevelam as a viable treatment option for HeFH.

METHODS

A literature search using Medline (1966-03 May 2010), PubMed (1950-03 May 2010), Science Direct (1994-03 May 2010), and International Pharmaceutical Abstracts (2004-2010) was performed using the search term colesevelam. English language, original research, and review articles were examined, and citations from these articles were also assessed. The manufacturer's prescribing information and the Food and Drug Administration review of the new drug application for the powder formulation were also examined.

RESULTS

A 32-week trial was performed investigating the efficacy of colesevelam as monotherapy or combination therapy with a stable statin regimen. Upon completion of the trial, significant benefits were found in regard to the treatment of HeFH and the lowering of low-density lipoprotein cholesterol, total cholesterol, and other secondary measures. Safety and tolerability were also examined throughout the duration of the clinical trial, with adverse drug reactions considered mild in severity.

CONCLUSION

Colesevelam has been shown to reduce low-density lipoprotein cholesterol levels significantly in pediatric/adolescent patients with HeFH, while maintaining a mild side effect profile. Although further research would be beneficial for long-term effects in this population, colesevelam should be considered when developing a treatment regimen for HeFH in the pediatric/adolescent population.

Evaluation and management of hyperlipidemia in children and adolescents

PURPOSE OF REVIEW

To review the recent findings on evaluation and management of dyslipidemia in childhood and adolescence, giving a critical view on new therapeutic approaches.

RECENT FINDINGS

In 2008, the American Academy of Pediatrics released an updated policy statement recommending more frequent screening to detect dyslipidemia in childhood and the first-line use of statins in children with dyslipidemia who did not respond to lifestyle intervention and who were more than 8 years of age. These recommendations have caused a lot of controversy within the medical community and media. This debate is also sharpened by the fact that only few trials have investigated the long-term efficacy of statins on prevention of adult cardiovascular disease, their application in dyslipidemias other than familial hypercholesterolemia and the use of new pharmacological tools.

SUMMARY

The purpose of our paper could not be achieved clearly without a review of the physiology of cholesterol metabolism together with an analysis of causes of primary and secondary dyslipidemia affecting children. Moreover, recent knowledge on lipid-lowering therapy is reviewed.