Association of serum apolipoprotein A-I (but not high-density lipoprotein cholesterol) with healed myocardial infarction in men independent of serum insulin and C-peptide

Peptídeo C e mortalidade cardiovascular: revisão sistemática e metanálise

Objetivo

Analisar as evidências de associação entre peptídeo C e mortalidade cardiovascular e geral disponíveis na literatura.

Métodos

Foi realizada uma revisão sistemática das bases de dados MEDLINE e EMBASE. Foram incluídos artigos publicados em inglês, português ou espanhol relatando estudos observacionais que investigaram a associação entre o peptídeo C e a mortalidade cardiovascular e geral. Buscou-se ainda avaliar a associação entre peptídeo C e fatores de risco cardiometabólicos, fatores hemodinâmicos e medidas antropométricas. A qualidade metodológica dos estudos foi avaliada de acordo com os critérios da escala Newcastle-Ottawa.

Resultados

Foram identificados 107 estudos relacionados ao tema. Ao final do processo de triagem, foram incluídos 18 artigos que apresentavam dados sobre a associação entre peptídeo C e risco cardiovascular. Cinco estudos forneceram dados sobre a relação entre peptídeo C e mortalidade cardiovascular e geral. O peptídeo C esteve associado positivamente ao IMC em chineses, e inversamente ao HDL colesterol em amostras populacionais na Ásia, Oriente Médio e Estados Unidos. Todavia, não foi possível realizar metanálise para os componentes de risco cardiovascular. Por outro lado, o peptídeo C esteve associado com a mortalidade cardiovascular (RR = 1,62; IC95%: 0,99 a 2,66) e geral (RR = 1,39; IC95%: 1,04 a 1,84).

Conclusão

Na revisão sistemática e metanálise realizadas, os níveis séricos de peptídeo C estiveram associados positivamente com a mortalidade geral em todos os indivíduos e com a mortalidade cardiovascular em pessoas sem comorbidades. Com base nesses resultados, é possível recomendar o emprego do peptídeo C na prática clínica como proxy da condição de resistência à insulina associada a mortalidade cardiovascular.

Proteomic biomarkers in second trimester amniotic fluid that identify women who are destined to develop preeclampsia

OBJECTIVES

This study investigated whether proteomic analysis of amniotic fluid (AF) in the early second trimester can be used to predict the development of preeclampsia.

METHODS

Amniotic fluid samples were collected at the time of genetic amniocentesis (15-19 weeks of gestation) from women who subsequently developed preeclampsia and from gestational age-matched normotensive controls (n = 10 for each). Amniotic fluid samples were subjected to proteomic analysis using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry, sodium dodecyl sulfate polyacrylamide gel coupled with in-gel tryptic digestion, electrospray ionization tandem mass spectrometry (MS/MS), immunodepletion assays, and enzyme-linke immunosorbent assay.

RESULTS

Five proteomic biomarkers were identified, which were differentially expressed in women who subsequently developed preeclampsia compared with those women who did not; four of these peaks were significantly upregulated (mass-to-charge ratio of 9080 [P = .006], 14 045 [P = .010], 14 345 [P = .049], and 28 087 [P = .006]) and one was significantly downregulated (mass-to-charge ratio of 4679 [P = .014]) in women who subsequently developed preeclampsia. Using electrospray ionization MS/MS and immunodepletion assays, two protein peaks were identified as albumin fragment and apolipoprotein A-I.

CONCLUSIONS

Using proteomic technology, this study identified protein biomarkers that are differentially expressed in the early second trimester AF from women who subsequently develop preeclampsia compared with women who remained normotensive. Early identification of women at risk of developing preeclampsia will allow clinicians to better optimize maternal and perinatal outcomes.

Invited commentary: lipoproteins and dementia - is it the apolipoprotein A-I?

Because of the aging of the population, dementia has become a major public health problem. There has been growing evidence for a possible association between lipids and dementia. A large body of literature has demonstrated multiple hypothesized biologic links between lipids and neurodegenerative or other biologic pathways connected to dementing processes. However, the epidemiologic associations have been conflicting: dyslipidemia at middle age, but not in later life, seems to be associated with higher dementia risk in some but not all studies. Results from the Honolulu-Asia Aging Study reported by Saczynski et al. (Am J Epidemiol 2007;165:985-92) suggest that lipoprotein constituents, such as apolipoprotein A-I, a major component of the high density lipoprotein, may be more informative in enlightening the association between lipids and dementia. In this commentary, the epidemiology and biology of apolipoprotein A-I in relation to dementia is reviewed.

Associations of insulin-like growth factors, insulin-like growth factor binding proteins and acid-labile subunit with coronary heart disease

OBJECTIVE

IGFs and their binding proteins (IGFBPs) are produced both systemically and locally by cells of the cardiovascular system. As growth promoters, they may play a role in atherosclerosis.

DESIGN

Case-control, cross-sectional.

PATIENTS

A total of 95 nondiabetic male patients with coronary heart disease (CHD) and 92 probands from the Prospective Cardiovascular Munster (PROCAM) who were below the age of 60 years and matched by age, body mass index (BMI) and smoking habits.

MEASUREMENTS

We analysed the strength and independence of associations of angiographically assessed presence of CHD with BMI, systolic and diastolic blood pressure, total, high-density lipoprotein (HDL) and LDL cholesterol, triglycerides, lipoprotein(a), apolipoproteins A-I and B, total and free IGF-I, IGF-II, IGFBP-1, IGFBP-3, IGFBP-5, acid-labile subunit (ALS), insulin, C-peptide, testosterone, DHEAS and sex hormone binding globulin.

RESULTS

Using multivariate statistical analysis, the presence of CHD had significant positive associations with total IGF-I, IGFBP-5, ALS and IGFBP-3. These associations were independent of each other as well as of traditional risk factors, insulin and sex hormones.

CONCLUSION

These observations may indicate a pathogenetic role of the GH/IGF axis in coronary atherosclerosis.

A Shot of Good Cholesterol

One of the American Heart Association's Top 10 Research Advances for the Treatment of Heart Disease is the use of a synthetic form of high-density lipoprotein (HDL) to reduce coronary atherosclerosis (JAMA. 2003;290:2292-2300). While HDL has not been a target for therapy for dyslipidemias, new insight into the major protein component of HDL, apolipoprotein A-I, may lead to new therapies. Apolipoprotein A-I was recently found to be a better predictor of cardiovascular events than is low-density lipoprotein (Am Heart J. 2003;146:227-233; J Intern Med. 2004;255:188-205). This article reviews the recent study by Nissen and colleagues describing the finding of a genetic mutation in HDL in some persons in Italy and the subsequent development of a synthetic form of HDL to be used as an infusion to successfully target atherosclerotic lesions (JAMA. 2003;290:2292-2300). In addition, controversies related to HDL cholesterol as a target for therapy are reviewed. Implications for nursing research, education, and practice are also described.

A dietary pattern derived to explain biomarker variation is strongly associated with the risk of coronary artery disease

BACKGROUND

In previous studies, dietary patterns were derived in different populations without regard to a specific outcome.

OBJECTIVE

The objective was to apply a new statistical method to construct a specific dietary pattern that is strongly associated with the risk of coronary artery disease (CAD).

DESIGN

We applied reduced rank regression to a sample of 200 cases and 255 controls from the Coronary Risk Factors for Atherosclerosis in Women (CORA) Study. The CAD-specific dietary pattern was constructed by choosing intake data for 49 food groups as predictors and 5 established biomarkers for CAD as responses.

RESULTS

A high score for the constructed dietary pattern was characterized by high intakes of meat, margarine, poultry, and sauce and low intakes of vegetarian dishes, wine, vegetables, and whole-grain cereals. After adjustment for known CAD risk factors, the relative risks from the lowest to the highest quintiles of the pattern score were 1.0, 1.1, 3.6, 6.2, and 12.3 (95% CI: 4.9, 30.9; P for trend < 0.0001). There was an approximate 4.5-fold difference in C-reactive protein and a 2-fold difference in C-peptide between the highest and lowest score quintiles of the study population. HDL-cholesterol concentrations ranged from 70 mg/dL in the lowest quintile to 49 mg/dL in the highest quintile of dietary pattern score.

CONCLUSION

The new statistical method, reduced rank regression, may be a useful tool for identifying dietary patterns that simultaneously affect the concentrations of known CAD biomarkers and the risk of developing CAD.

An elevation of triglycerides reflecting decreased triglyceride clearance may not be pathogenic – relevance to high-carbohydrate diets

The fact that carbohydrate-rich diets often increase plasma triglycerides has led some to question the wisdom of such diets. This increase is primarily attributable to a decrease in the efficiency of triglyceride clearance -- whereas the elevation of triglycerides observed in insulin-resistant subjects stems mainly from increased hepatic production of VLDL particles. There is growing reason to suspect that the increased coronary risk associated with elevated triglycerides in Western epidemiology reflects the fact that high triglycerides are a marker for insulin resistance syndrome, rather than any inherent pathogenic role of triglycerides per se. Thus, endothelial dysfunction is seen only in those hypertriglyceridemic subjects who are insulin resistant, and is absent in patients whose markedly elevated triglycerides reflect genetically defective lipoprotein lipase activity. Triglyceride levels are relatively high in certain Third World societies which are virtually immune to coronary disease so long as they persist in their traditional very-low-fat diets; in Ornish's celebrated study, a moderate rise in triglycerides coincided with a marked reduction in coronary events. Although the particle size of both LDL and HDL tends to decrease when triglyceride levels are high, it is questionable whether this effect has a major pathogenic impact. The one clear drawback of high-carbohydrate diets is a decrease in HDL particle number, resulting from decreased hepatic production of apoA-I; this effect is seen whether or not triglycerides increase. The very favorable effects of very-low-fat, whole food, quasi-vegan diets on LDL cholesterol, insulin sensitivity, and body weight appear to more than compensate for this decrease in HDL; it is notable that HDL levels tend to be quite low in Third World cultures at minimal risk for coronary disease. On the other hand, this decrease in HDL may be of more significance in the context of omnivore diets only moderately low in fat, as suggested by the fact that diets higher in unsaturated fats emerge as more protective in Western prospective epidemiology. The tendency of high-carbohydrate diets to boost triglycerides can be minimized by exercise training, supplemental fish oil, an emphasis on fiber-rich, low-glycemic-index whole foods, and the "spontaneous" weight loss often seen with ad libitum consumption of such diets -- measures which are highly recommendable whether or not triglycerides are a concern.