Apolipoprotein A-I and B levels in adolescents; a trial to define subjects at risk for coronary heart disease

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Gap analysis of pediatric reference intervals for risk biomarkers of cardiovascular disease and the metabolic syndrome

The childhood obesity epidemic has begun to compromise the health of the pediatric population by promoting premature development of atherosclerosis and the metabolic syndrome (MS), both of which significantly increase the risk of cardiovascular disease (CVD) early in life. As a result, recently, there has been increased recognition of the need to assess and closely monitor children and adolescents for risk factors of CVD and components of the MS. Serum/Plasma biomarkers including total cholesterol, triglycerides, HDL-C, LDL-C, insulin and C-peptide have been used for this purpose for many years. Recently, emerging biomarkers such as apolipoprotein AI, apolipoprotein B, leptin, adiponectin, free fatty acids, and ghrelin have been proposed as tools that provide valuable complementary information to that obtained from traditional biomarkers, if not more powerful predictions of risk. In order for biomarkers to be clinically useful in accurately diagnosing and treating disorders, age-specific reference intervals that account for differences in gender, pubertal stage, and ethnic origin are a necessity. Unfortunately, to date, many critical gaps exist in the reference interval database of most of the biomarkers that have been identified. This review contains a comprehensive gap analysis of the reference intervals for emerging and traditional risk biomarkers of CVD and the MS and discusses the clinical significance and analytical considerations of each biomarker.

Lipoproteins in patients with isolated hyperuricemia

BACKGROUND

There have been described abnormalities in the lipoprotein profile of hyperuricemic patients, it has not been clarified wether these abnormalities are due to the hyperuricemia or to the dyslipema often associated to these patients. Our aim is to study the apolipoprotein profile in hyperuricemic patients without dyslipemia compared to a control population.

PATIENTS AND METHODS

30 hyperuricemic patients and 26 healthy controls. Measurements were of blood uric acid, total cholesterol, total triglycerides, creatinine, HDL-C, and VLDL cholesterol, triglyceride, Apo B, Apo CII and Apo CIII (1 and 2). Uric acid clearance and fractionated excretion were measured in 24 h. urine samples.

RESULTS

No significant differences were found between hyperuricemic and control patients in cholesterol, triglycerides and apo B in VLDL, or LDL and HDL cholesterol. The levels of apo B, Apo AI levels and apo CIII/apo CII were similar in the hyperuricaemic and controls.

CONCLUSIONS

There are two types of hyperuricaemic patients, one group associated to hyperlipideamia and would be included in the X Syndrome. The other group not associated to other metabolic abnormalities. Is important to distinguish between these two groups to define the prognosis of a given patient because the greater cardiovascular risk linked hyperuricaemic patients could be related to the association to others cardiovascular risks factors.

Serum lipid values in adolescents are related to family history, infant feeding, and physical growth

Total serum cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), apolipoprotein A-I (apo A-I), apolipoprotein B (apo B), and lipoprotein (a) (Lp(a)) were analysed in 879 14- and 17-year-old healthy adolescents (477 boys and 402 girls), and related to family history of cardiovascular disease, early feeding, weight and length at birth, and physical growth during infancy and childhood. Mean TC was significantly higher in girls than in boys (4.4 and 4.2 mmol/l, respectively, both age-groups together). High TC values ( > 5.2 mmol/l) were more prevalent in girls than in boys: 14% and 17% compared to 6% and 12% in 14- and 17-year-old girls and boys, respectively. Mean TC and LDL-C values were lower during mid-puberty in both boys and girls while, in boys but not in girls, mean HDL-C values decreased and TG values increased successively with increasing pubertal stage. Girls who were taking oral contraceptives had higher mean values of TC (4.91/4.39 mmol/l), TG (1.32/0.83 mmol/l), and apo B (0.89/0.73 g/l). Boys with a family history of early deaths ( < 55 years) from myocardial infarction and girls with a family history of cerebral haemorrhage/thrombosis in fathers had higher mean values of TC (4.55/4.17 and 5.03/4.40 mmol/l, for boys and girls, respectively), LDL-C (2.84/2.47 and 3.08/2.56 mmol/l), and apo B (0.73/0.70 and 0.86/0.73 g/l). Adolescents with short duration of breast feeding ( < 6 months), or early introduction of infant formula, had higher mean values of TC (4.29/4.14 mmol/l) and apo B (0.72/0.68 g/l). There were no significant correlations between serum lipid values and body weight or length at birth, but adolescents with high LDL-C (upper quartile) seemed to have lower attained heights during infancy and childhood. In conclusion, this study shows that serum lipids in adolescence are primarily related to age and sex but also to early determinants like family history of cardiovascular diseases, infant feeding, and early physical growth.

Lipid screening in paediatrics for early detection of cardiovascular risks

The purpose of the study was to try to detect at an early stage the important cardiovascular risk factors associated with increased concentrations of blood lipids, notably cholesterol. The trial was based on the screening of 102 families, including 219 children, 8-18 years of age and their parents. A group of young adults, 19-25 years of age, was included in the study. All subjects were derived from a paediatric practice. In addition to total cholesterol, VLDL-, LDL-, HDL-cholesterol and apolipoproteins A-I and B were also measured. The study identified a significant number of school-children and adolescents with hyperlipidaemia, predominantly hypercholesterolaemias type II-A. There was a close relationship between their blood lipids and those of their parents. The study demonstrates the importance of including parents in studies of this kind. Total cholesterol proved to be a reliable parameter for screening. The value of apolipoproteins in such screening is discussed.

Hyperlipidemia in school children with family histories of premature coronary heart disease

Children starting their schooling were given a questionnaire asking about the occurrence of premature (before 50 years of age in men, 55 years in women) coronary heart disease (CHD) in first degree relatives. 1,920 of 2,069 questionnaires were answered, 140 of the 7-year-old children were reported to have a first degree relative with premature CHD, 84 of these 140 families agreed to participate in our study. In 79 of the 84 families both the child and the parent at 'high risk' were tested. In the initial test 19 of 84 children had total cholesterol (TC) levels above the 95th percentile (greater than 5.35 mmol/l). In the repeat test 12 of the 19 TC tests remained abnormal and all 12 also had LDL-cholesterol (LDL-C) levels above the 95th percentile (greater than 3.40 mmol/l). None had abnormal HDL-cholesterol or triglyceride levels. Among the high risk parents, 12 of 79 had abnormal initial blood lipid tests. In the repeat test 10 parents had both TC and LDL-C levels above the 95th percentile. In five families both the child and the parent had abnormal TC and LDL-C levels. In conclusion, a considerable proportion of children and parents with family histories of premature CHD have TC and LDL-C concentrations above the 95th percentile (in the present study, about 40 individuals in 140 high-risk families, if the parent and child considered at high risk all had agreed to participate). Prevention of heart disease should begin in childhood when patterns of life-style are developed. Identification by obtained family histories as in the current study may be a method of choice.

Promoting good nutrition for today and the year 2000

Present evidence and recommendations for promoting health and preventing disease by diet are summarized in this article. Progression studies relating to these issues over the past 6 years and relevant documents dealing with these and other public health measures are reviewed.

Atherosclerosis precursors in Finnish children and adolescents. VI. Serum apolipoproteins A-I and B

The concentrations of apolipoproteins A-I and B were determined in 1,341 3- to 18-year-old children and adolescents from five urban and 12 rural communities. The analyses were made with radial immunodiffusion. The mean concentrations (+/- S.D.) of apo A-I and apo B were 152 +/- 25 and 94 +/- 22 mg/100 ml, respectively. 3-year-old children had the highest apo B levels which then decreased with advancing age in both sexes. Boys tended to have lower levels of apo B than girls. Apo A-I concentration was significantly higher in the 9- and 12-year-old boys than in the other age groups but showed no age-bound trend in girls. The apo A-I to apo B ratio increased with age in both sexes. The concentration of apo A-I was significantly lower, and that of apo B higher, in children living in eastern Finland in comparison with those from the western part of the country. This difference and a higher HDL-cholesterol to apo A-I ratio in both sexes in eastern Finland may be associated with the regional differences in the prevalence of coronary heart disease in this country.