Hipercolesterolemia familiar. Enfoque desde la Pediatría / Familial hypercholesterolemia. A pediatric focus

La Hipercolesterolemia Familiar (HF) es una enfermedad hereditaria frecuente que se caracteriza por niveles elevados de colesterol ligado a las lipoproteínas de baja densidad (C-LDL). El exceso de LDL se acumula en las arterias produciendo aterosclerosis prematura. El diagnóstico y tratamiento desde la infancia mejoran el pronóstico de la enfermedad. Existe subdiagnóstico de la HF lo que provoca muertes prematuras por enfermedad cardiovascular (ECV). Para mejorar el subdiagnóstico la Sociedad Argentina de Pediatría propuso en el año 2015 realizar tamizaje universal al ingreso escolar. Es relevante entonces que el pediatra pueda diagnosticar la hipercolesterolemia y diferenciar las hipercolesterolemias monogénicas o familiares, de las secundarias (AU)

Familial hypercholesterolemia (FH) is a common hereditary disease that is characterized by high cholesterol levels, linked to low-density lipoproteins (LDL). Excess LDL accumulates in the arteries leading to premature atherosclerosis. Early diagnosis and treatment since childhood improve the prognosis of the disease. FH is underdiagnosed resulting in premature death due to cardiovascular disease (CVD). To improve diagnosis, in 2015 the Argentine Society of Pediatrics proposed a universal screening program at school age. It is relevant, therefore, for the pediatrician to be able to diagnose hypercholesterolemia and differentiate monogenic or familial from secondary hypercholesterolemia (AU)

Microvascular Function and Endothelial Progenitor Cells in Patients with Severe Hypercholesterolemia and the Familial Hypercholesterolemia Phenotype.

OBJECTIVE: To evaluate endothelial progenitor cells (EPCs) and systemic microvascular function in patients with severe hypercholesterolemia, comparing patients with the definite familial hypercholesterolemia (FH) phenotype (DFH) or probable/possible FH phenotype (PFH). There is a large spectrum of atherosclerotic disease between these two clinical phenotypes of FH, and to acquire further knowledge of the pathophysiology of vascular disease in both is desirable. METHODS: Subjects with severe hypercholesterolemia, defined as low-density lipoprotein cholesterol (LDL-C) >190 mg/dL, were classified as DFH or PFH and underwent measurement of the number of EPCs by flow cytometry and evaluation of cutaneous microvascular reactivity using a laser speckle contrast-imaging system with iontophoresis of acethylcholine (ACh) or sodium nitroprusside. EPCs were defined as CD45- or CD45low, CD34+CD133+CD309+ cells. Categorical variables were compared using Fisher test and continuous variables with Student t test or Mann-Whitney test, and a value of p < 0.05 was considered statistically significant. RESULTS: Patients with DFH had higher LDL-C than those with PFH. There was no difference in the median number of EPCs between patients with DFH or PFH, but there was a significant reduction of endothelial-dependent, ACh-induced vasodilatation in the former. CONCLUSION: Patients with DFH have impaired microvascular endothelial-dependent vasodilatation compared to those with PFH, indicating more severe vascular disease in the former.

A 10-year experience using combined lipid-lowering pharmacotherapy in children and adolescents.

BACKGROUND: Current pediatric guidelines for heterozygous familial hypercholesterolemia (HeFH) propose pharmacotherapy (PT) with statins from age 8 to 10 years; however, schemes with absorption inhibitors combined with statins, could be started earlier. The aim of the study was to show the 10-year results of a combined treatment protocol. METHODS: Prospective, descriptive and analytical study. Pediatric patients (n=70; mean age at PT initiation 9.3 years [range, 2-17.5]) with HeFH who required PT between 2005 and 2015 were included. All patients ≥10 years, with LDL >190 mg/dL or >160 mg/dL with one cardiovascular risk factor (CVRF) or >130 mg/dL with two or more CVRF; and those patients 5-10 years and with LDL-C >240 mg/dL or a family history of a cardiovascular event before 40 years, were medicated. After a period on a lipid-lowering diet (LLD), all patients were started on ezetimibe. Patients who did not achieve the treatment goal were given statins. The variables were: age, age at PT initiation, duration of PT, initial LDL-C, mean LDL-C during ezetimibe monodrug therapy, mean LDL-C during combined PT, and percentage of LDL decrease. RESULTS: LDL-C levels were: Baseline: 235 mg/dL±55; after 3 months on ezetimibe: 167 mg/dL±47 (decrease: -27.62%). In 18 patients who did not reach the treatment goal atorvastatin was added and their LDL-C decreased -41.5% (p: 0.02). Overall, mean final LDL-C was 155 mg/dL±30.4 (range, 98-257) and treatment goals were reached in 74% of the patients. No severe side effects were reported. CONCLUSIONS: Combined and sequential treatment starting at early ages was shown to be safe and effective over this follow-up period.

High lipoprotein(a) concentrations are associated with impaired endothelial function in children.

OBJECTIVE: To examine the association between familial high lipoprotein(a), or Lp(a), concentrations and endothelial function in children participating in the Special Turku Coronary Risk Factor Intervention Project study. STUDY DESIGN: Seven-month-old children (n = 1062) with their families were randomized to a risk intervention group or to a control group. The intervention group received individualized dietary counseling to reduce the total cholesterol concentration. Children's Lp(a) and lipid values were measured repeatedly. At age 11 years, children were recruited to an ultrasound study of the flow-mediated dilation (FMD) of the brachial artery. The association between relative peak FMD and Lp(a) concentration was examined in 198 control and 193 intervention group children by linear regression analyses adjusted for sex, total cholesterol concentration, and basal artery diameter. The analyses were made in both the control and intervention groups and in the familial risk children who had a parent with Lp(a) concentration greater than 250 mg/l. RESULTS: Lp(a) concentrations were similar at age 11 years in the intervention and control groups. In all control children, FMD (%) associated inversely with Lp(a) concentration: (ß [%/1000 mg/L] = -3.74, 95% CI [-6.43, -1.45]; P = .007) and in 68 familial risk children (ß = -4.92, 95% CI [-8.18, -1.66]; P = .0037). In the intervention group the associations were lacking (P > .5), and FMD in the children with high Lp(a) concentrations (>500 mg/L, n = 12) had no attenuation (P = .027). CONCLUSIONS: Familial high Lp(a) concentration is associated with attenuated endothelial function. This association may be mitigated by an early lifestyle intervention. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00223600.

Association of Peripheral Arterial and Cardiovascular Diseases in Familial Hypercholesterolemia / Associação das Doenças Arterial Periférica e Cardiovascular na Hipercolesterolemia Familiar

Background: Familial hypercholesterolemia (FH) is an autosomal dominant genetic disease characterized by an elevation in the serum levels of total cholesterol and of low-density lipoproteins (LDL- c). Known to be closely related to the atherosclerotic process, FH can determine the development of early obstructive lesions in different arterial beds. In this context, FH has also been proposed to be a risk factor for peripheral arterial disease (PAD). Objective: This observational cross-sectional study assessed the association of PAD with other manifestations of cardiovascular disease (CVD), such as coronary artery and cerebrovascular disease, in patients with heterozygous FH. Methods: The diagnosis of PAD was established by ankle-brachial index (ABI) values ≤ 0.90. This study assessed 202 patients (35% of men) with heterozygous FH (90.6% with LDL receptor mutations), mean age of 51 ± 14 years and total cholesterol levels of 342 ± 86 mg /dL. Results: The prevalences of PAD and previous CVD were 17% and 28.2 %, respectively. On multivariate analysis, an independent association between CVD and the diagnosis of PAD was observed (OR = 2.50; 95% CI: 1.004 - 6.230; p = 0.049). Conclusion: Systematic screening for PAD by use of ABI is feasible to assess patients with FH, and it might indicate an increased risk for CVD. However, further studies are required to determine the role of ABI as a tool to assess the cardiovascular risk of those patients. .

Fundamento: A hipercolesterolemia familiar (HF) é uma doença de herança genética autossômica dominante caracterizada pela elevação dos valores séricos de colesterol total e das lipoproteínas de baixa densidade (LDL-c). Conhecida por estar estreitamente relacionada ao processo aterosclerótico, a HF pode determinar o desenvolvimento de lesões obstrutivas precoces em distintos leitos arteriais. Nesse contexto, a HF também tem sido proposta como fator de risco para a doença arterial periférica (DAP). Objetivo: Avaliamos, por meio de um estudo transversal e observacional, a associação da DAP com outras manifestações de doença cardiovascular (DCV), isto é, doença arterial coronária e cerebrovascular em portadores de HF heterozigótica. Métodos: diagnóstico de DAP foi estabelecido pela medida do índice tornozelo-braquial (ITB) com valores ≤ 0,90. Foram estudados 202 pacientes com HF (90,6% apresentando mutações no receptor da LDL), idade 51 ± 14 anos, colesterol total 342 ± 86 mg/dL e 35% do sexo masculino. Resultados: As prevalências de DAP e de DCV prévia foram 17% e 28,2%, respectivamente. Houve associação independente da DAP com a DCV (OR = 2,50, IC 95% 1,004-6,230, p = 0,049) após análise multivariada. Conclusão: A pesquisa sistemática da DAP por meio do ITB é factível na avaliação de portadores de HF e pode sinalizar aumento no risco de DCV. Contudo, mais estudos são necessários para determinar o papel do uso do ITB como ferramenta para avaliação do risco cardiovascular nessa população. (Arq Bras Cardiol. 2014; 103(2):118-123) .

Association of peripheral arterial and cardiovascular diseases in familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant genetic disease characterized by an elevation in the serum levels of total cholesterol and of low-density lipoproteins (LDL- c). Known to be closely related to the atherosclerotic process, FH can determine the development of early obstructive lesions in different arterial beds. In this context, FH has also been proposed to be a risk factor for peripheral arterial disease (PAD). OBJECTIVE: This observational cross-sectional study assessed the association of PAD with other manifestations of cardiovascular disease (CVD), such as coronary artery and cerebrovascular disease, in patients with heterozygous FH. METHODS: The diagnosis of PAD was established by ankle-brachial index (ABI) values ≤ 0.90. This study assessed 202 patients (35% of men) with heterozygous FH (90.6% with LDL receptor mutations), mean age of 51 ± 14 years and total cholesterol levels of 342 ± 86 mg /dL. RESULTS: The prevalences of PAD and previous CVD were 17% and 28.2 %, respectively. On multivariate analysis, an independent association between CVD and the diagnosis of PAD was observed (OR = 2.50; 95% CI: 1.004 - 6.230; p = 0.049). CONCLUSION: Systematic screening for PAD by use of ABI is feasible to assess patients with FH, and it might indicate an increased risk for CVD. However, further studies are required to determine the role of ABI as a tool to assess the cardiovascular risk of those patients.

Statin restores cardiac autonomic response to acute hypoxia in hypercholesterolaemia.

BACKGROUND: Hypercholesterolaemia may alter cardiovascular autonomic function. We investigated the autonomic cardiovascular regulation during normoxia and hypoxia in familial isolated HC patients with or without statin treatment. MATERIALS AND METHODS: Low (LF-RR) and high (HF-RR) components of spectral analysis of RR interval and systolic arterial pressure (LF-SAP) were obtained during 5 min of normoxia and isocapnic hypoxia (10% O(2) ) in 10 normotensive familial HC patients without medication, in seven HC patients after a 12-week treatment period with 40 mg of simvastatin (HC + SVT) and in eight matched normal volunteers (CO). RESULTS: The HC patients had significant impairment of cardiac autonomic modulation parameters compared with CO at normoxia, which was maintained or even accentuated during hypoxia; these parameters included lower total variance of RR, increased normalized LF-RR, decreased normalized HF-RR, increased LF-RR/HF-RR ratio, higher LF-SAP component and reduced α index. However, the HC + SVT group had a significant improvement in all parameters: the LF-RR and LF-SAP decreased (indicating a decrease in cardiac and vascular sympathetic activity), the HF-RR increased (indicating an increase in parasympathetic activity) and the spontaneous baroreflex sensitivity improved. These changes were detected at normoxia and were maintained during hypoxia. CONCLUSIONS: Our data are the first to show that isolated HC is characterized by an increase in cardiac and vasomotor sympathetic drive, a decrease in cardiac vagal modulation and baroreflex impairment during normoxia and hypoxia. In addition, our data suggest that statin treatment has a potential role in restoring the physiological cardiovascular autonomic control at baseline and during cardiovascular challenge.

Atorvastatin treatment improves myocardial and peripheral blood flow in familial hypercholesterolemia subjects without evidence of coronary atherosclerosis.

BACKGROUND: Hypercholesterolemia induces early microcirculatory functional and structural alterations that are reversible by cholesterol reduction. Real time myocardial contrast echocardiography (RTMCE) and vascular ultrasound evaluate the effects of hyperlipidemia on peripheral and central blood flow reserve. This study investigated the effects of lipid-lowering therapy on coronary and peripheral artery circulation in patients with familial hypercholesterolemia (FH). METHODS: RTMCE and vascular ultrasound were performed in 10 healthy volunteers (validation group) at baseline and after 12-week clinical observation, and in 16 age- and sex-matched FH patients without obstructive coronary artery disease (CAD) by computed tomography angiography at baseline and after 12-week atorvastatin treatment. Indexes of relative myocardial blood flow (MBF) were obtained at rest and during adenosine infusion. RESULTS: In validation group, there was no significant difference between flow-mediated dilation (FMD) at baseline and after 12 weeks (0.15 ± 0.02 vs. 0.14 ± 0.03; P = 0.39). Similarly, no differences were observed in MBF reserve at baseline and after 12 weeks (3.31 ± 0.63 vs. 3.48 ± 0.89; P = 0.89). FMD was blunted in FH patients, at baseline, as compared with validation group (0.08 ± 0.04 vs. 0.15 ± 0.02; P < 0.001) and became similar to that group (0.13 ± 0.05 vs. 0.14 ± 0.03; P = 0.07) after treatment. MBF reserve was blunted at baseline in FH patients in comparison with the validation group (2.78 ± 0.71 vs. 3.31 ± 0.63; P = 0.003). After treatment, MBF reserve values were no longer different (3.43 ± 0.66 and 3.48 ± 0.89; P = 0.84, respectively, for FH and validation groups). CONCLUSION: Patients with FH and no obstructive CAD have blunted MBF reserve and lower FMD values as compared with healthy volunteers. Both FMD and MBF reserve were normalized after atorvastatin treatment.

Hipercolesterolemia familiar / Familial hypercholesterolemia

A hipercolesterolemia familiar é uma doença genética, caracterizada por elevações dos níveis de colesterol plasmático, resultante da fração que não é removida adequadamente da circulação. São descritas mais de 600 mutações envolvidas nos mecanismos de síntese e expressão dos receptores da lipoproteína de baixa densidade (LDL), o que se traduz em redução ou em não funcionamento desses mecanismos. A forma de transmissão da mutação é autossômica dominante, o que resulta em dois fenótipos distintos: a forma homozigótica, rara, com prevalência de 1 em 1 milhão de indivíduos e valores de LDL-Colesterol acima de 600 mg/dl, além da presença de aterosclerose precoce, com acometimento cardiovascular já na primeira infância e adolescência; e a forma heterozigótica, mais frequente, que acomete 1 em 500 indivíduos, em que os níveis de LDL-colesterol plasmático se situam, geralmente entre 200 mg/dl e 400 mg/dl, e na ausência de tratamento adequado a doença coronariana vai se estabelecer em homens antes dos 50 anos e em mulheres antes dos 60 anos. o diagnóstico é estabelecido por meio de critérios clínicos e pode ser confirmado pela determinação da mutação. O tratamento, bem como as metas lipídicas a serem alcançadas, baseiam-se na estratificação de risco desses pacientes, o qual avalia, entre outros fatores, a presença de aterosclerose subclínica por meio da avaliação do complexo íntima média da carótida e do cálcio coronário. O diagnóstico de hipercolesterolemia familiar permite a identificação dessa doença em outros componentes assintmáticos em uma mesma família, podendo-se estabelecer o tratamento adequado da hipercolesterolemia, o que irá prevenir eventos cardiovasculares futuros

Endothelial dysfunction occurs in children with two genetic hyperlipidemias: improvement with antioxidant vitamin therapy.

OBJECTIVE: To measure endothelium-dependent vascular relaxation in children with two genetic hyperlipidemias and to assess the effect of antioxidant vitamins on endothelial dysfunction. STUDY DESIGN: Vascular reactivity in the brachial artery was measured in 45 individuals between 6 and 21 years of age (18 with familial hypercholesterolemia [FH], 15 with familial combined hyperlipoproteinemia [FCH], 12 control subjects) with the use of high-resolution two-dimensional ultrasonography. Follow-up studies were done for 11 children after 6 weeks of treatment with tocopherol (400 IU twice a day) and ascorbic acid (500 mg twice a day). RESULTS: The mean percent change in diameter during reactive hyperemia was 2.1 +/- 2.2 (SD) and 2.7 +/- 4.4, in FH and FCH, respectively, compared with 12. +/- 4.9 among control subjects (p < 0.001 in each case). The mean percent dilation was significantly increased (2.8 +/- 1.6 to 9.1 +/- 2.3) (p < 0.001) after antioxidant therapy. CONCLUSIONS: Impaired endothelium-dependent vasoregulation occurs in children with FCH as well as in those with FH. The improvement in vascular reactivity observed during supplementation with antioxidant vitamins suggests that reactive oxygen species derived from oxidized lipoproteins may be responsible for the impairment of vasoregulation in subjects with hyperlipidemia.

Effect of policosanol on platelet aggregation in type II hypercholesterolemic patients.

Policosanol is a cholesterol-lowering drug with concomitant antiplatelet effects proved in experimental models and healthy volunteers. This study reports the results of a 4-week, randomized, double-blind, placebo-controlled trial investigating the effects of policosanol on platelet aggregation in type II hypercholesterolemic patients. Patients started or continued on a step-one cholesterol-lowering therapy for 4 weeks and those with total cholesterol > 5.0 mmol/L despite dietary conditions were randomized to receive under double-blind conditions placebo or policosanol (10 mg/day) for 30 days. Both groups were similar at randomization. Effects of policosanol on platelet aggregation induced by arachidonic acid (3.2 mM), collagen (0.5-1 microgram/ml) and ADP (0.5-1 uM) were determined at baseline and after 30 days of treatment. Policosanol significantly reduced platelet aggregation induced by arachidonic acid and collagen, meanwhile it only inhibited significantly the platelet aggregation induced by the lowest doses of ADP (0.5 uM). No adverse events occurred during the trial. Only one patient (placebo) discontinued from the study because of arthralgia.

Hiperlipoproteinemias: manifestaciones cutáneas como marcador de enfermedad sistémica. Comunicación de tres casos / Hyperlipoproteinemias: Cutaneous manifestations as a marker of systemic disease. Report of three cases

Se presentan tres casos de hiperlipoproteinemia relacionados con enfermedad cardiovascular. La relación entre los niveles séricos altos de lipoproteínas de baja densidad y enfermedad cardiovascular está bien establecidad. La hiperlipoproteinemia tipo II es unas de las formas más frecuentes y graves de hipercolesterolemia. Los xantomas tendinosos son patognomónicos y se relacionan con concentraciones altas de lipoproteínas de baja densidad. Se hace incapié en la importancia de las manifestaciones cutáneas como marcador de enfermedad sistémica

Low-density lipoprotein apheresis as long-term treatment for children with homozygous familial hypercholesterolemia.

OBJECTIVE: To determine the safety and efficacy of long-term dextran sulfate-affinity column low-density lipoprotein (LDL) apheresis for the treatment of children with receptor-negative homozygous familial hypercholesterolemia (HFH). STUDY DESIGN: Two children with HFH (pretreatment cholesterol levels 22.1 to 24.7 mmol/L (ranges 850 to 950 mg/dl) began LDL apheresis treatments at ages 7 and 10 years, respectively. The LDL apheresis treatment interval was generally either 7 or 14 days; for the last 2 years of the study the treatment interval was 7 days. The patients had 167 and 188 LDL apheresis procedures during 64 and 70 months, respectively. RESULTS: Individual procedures decreased total blood cholesterol levels by 63% to 68%. When the treatment interval was 7 days, the patients' time-averaged mean total cholesterol levels decreased to 7.3 +/- 0.65 mmol/L (280 +/- 25 mg/dl) and 6.4 +/- 0.55 mmol/L (247 +/- 22 mg/dl), respectively. Both children remained clinically well with normal growth and development. There was significant regression of xanthomas in both patients. The older patient required heart surgery for preexisting aortic stenosis and coronary ostial stenosis, but neither patient had progression of hypercholesterolemia-related cardiovascular disease. With the exception of iron (deficiency in patient 1), there was no evidence of depletion of serum components. Adverse reactions to LDL apheresis were rare and never severe. CONCLUSIONS: Dextran sulfate-affinity column LDL apheresis is effective long-term treatment for children with receptor-negative HFH.