Troponin in diabetic patients with and without chronic coronary artery disease.

BACKGROUND: Cardiac-specific troponin detected with the new high-sensitivity assays can be chronically elevated in response to cardiovascular comorbidities and confer important prognostic information, in the absence of unstable coronary syndromes. Both diabetes mellitus and coronary artery disease are known predictors of troponin elevation. It is not known whether diabetic patients with coronary artery disease have different levels of troponin compared with diabetic patients with normal coronary arteries. To investigate this question, we determined the concentrations of a level 1 troponin assay in two groups of diabetic patients: those with multivessel coronary artery disease and those with angiographically normal coronary arteries. METHODS: We studied 95 diabetic patients and compared troponin in serum samples from 50 patients with coronary artery disease (mean age = 63.7, 58 % male) with 45 controls with angiographically normal coronary arteries. Brain natriuretic peptide and the oxidative stress biomarkers myeloperoxidase, nitrotyrosine and oxidized LDL were also determined. RESULTS: Diabetic patients with coronary artery disease had higher levels of troponin than did controls (median values, 12.0 pg/mL (95 % CI:10-16) vs 7.0 pg/mL (95 % CI: 5.9-8.5), respectively; p = 0.0001). The area under the ROC curve for the diagnosis of CAD was 0.712 with a sensitivity of 70 % and a specificity of 66 %. Plasma BNP levels and oxidative stress variables (myeloperoxidase, nitrotyrosine, and oxidized LDL) were not different between the two groups. In a multivariate analysis, gender (p = 0.04), serum glucose (0.03) and Troponin I (p = 0.01) had independent statistical significance. CONCLUSION: Troponin elevation is related to the presence of chronic coronary artery disease in diabetic patients with multiple associated cardiovascular risk factors. Troponin may serve as a biomarker in this high-risk population. TRIAL REGISTRATION: http://www.controlled-trials.com REGISTRATION NUMBER: ISRCTN26970041.

Efeito do metabolismo e função das lipoproteínas de alta densidade (HDL) em pacientes diabéticos tipo 2 com e sem doença coronária obstrutiva / Effect of metabolism and function of high density lipoprotein (HDL) in type 2 diabetic patients with and without obstructive coronary artery disease

Introdução:O diabetes mellitus tipo 2 (DM2) está associado ao aumento da mortalidade por doença arterial coronária (DAC). O DM2 afeta o metabolismo de lípides, levando à dislipidemia, caracterizada por hipertrigliceridemia e baixa concentração plasmática de HDL-colesterol. Transferências de lípides entre HDL e outras lipoproteínas são passos cruciais no metabolismo e função da HDL. Objetivo: Investigar se o desenvolvimento de DAC em pacientes com DM2 está associado com alterações na transferência de lípides para HDL. Métodos: Foram estudados 79 pacientes com DM2 portadores de DAC obstrutiva (DM2-DAC) e 76 pacientes com DM2 e artérias coronárias angiograficamente normais (DM2). Foram avaliados o perfil lipídico, apolipoproteínas, composição lipídica da HDL, dosagem de CETP e LCAT. No ensaio de transferência, as amostras de plasma foram incubadas por 1h a 37º com uma nanoemulsão artificial marcada com 3H-éster de colesterol e 14Cfosfolípides ou 3H -triglicérides e 14C-colesterol não esterificado. A quantificação da transferência de lípides da nanoemulsão doadora para a HDL foi feita após a precipitação da fração não HDL. O tamanho da HDL foi medido por laser light scattering. Resultados: Os pacientes DM2-DAC apresentaram maior concentração de colesterol total (DM2-DAC=218±48; DM2=193±36; p < 0,001), LDL-C (147±44 vs 124±33; p < 0,001) e apoB (103,1±20,4 vs 96,0 ± 19,5; p = 0,03) que o grupo sem DAC. Os grupos não mostraram diferença com relação à concentração plasmática de triglicérides (DM2-DAC=171 ± 73; DM2=154 ± 70; p=0,1) e HDL-C (41±9 vs 38±8; p=0,07). A transferência de éster de colesterol (4,0 ± 0,6 vs 4,3 ± 0,7; p=0,005) e de colesterol não esterificado (7,6 ± 1,2 vs 8,2±1,5; p=0,006) foi menor no grupo com DAC, porém esse grupo teve maior concentração de colesterol não esterificado no plasma (36,3 ± 8,0 vs 33,6±6,5 ;p=0,02). A concentração de CETP foi menor no grupo DM2DAC (2,1±1,0 vs 2,5 ±1,1; p=0,02 )....

Aim: Type 2 diabetes mellitus (DM2) is associated with morbidity and mortality secondary to coronary artery disease (CAD). DM2 affects lipid metabolism, and diabetic dyslipidemia is characterized by increased levels of tryglicerides and reduced levels of HDL-cholesterol. Lipid transfer between HDL and the other lipoproteins is a crucial step in HDL function and metabolism. Objective: The purpose of this study was investigate whether the susceptibility of patients with type 2 diabetes mellitus to develop CAD is related with alterations in lipid transfers to HDL. Methods: 79 patients with DM2 and obstructive CAD (DM2- CAD) and 76 with DM2 (DM2 group) and angiographic normal coronary arteries were studied. Lipid profile, apolipoproteins, HDL lipid composition, CETP and LCAT activity were evaluated. In the lipid transfer assay, fasting plasma samples were incubated for 1h at 37°C with a donor artificial nanoemulsion labeled with 3H -cholesteryl-esters and 14C-phospholipids or 3H-triglycerides and 14C-unesterified cholesterol. Radioactive lipids transferred from the donor nanoemulsion to HDL were quantified in the supernatant after chemical precipitation of non-HDL fractions and nanoemulsion. HDL size was measured by laser light scattering. Results: In DM2-CAD, total cholesterol (DM2- DAC=218 ± 48; DM2=193±36; p < 0,001), LDL-C (147 ± 44 vs 124±33; p < 0,001) and apoB (103,1±20,4 vs 96,0±19,5; p=0,03) were higher than in DM2 group. The groups showed no differences with respect to plasma triglycerides levels (DM2-DAC=171± 73; DM2=154 ± 70; p=0,1) nor HDL-C (41 ± 9 vs 38±8; p=0,07). DM2-CAD showed diminished transfer to HDL of esterified cholesterol (4,0±0,6 vs 4,3 ± 0,7; p = 0,005) and unesterified cholesterol (7,6 ± 1,2 vs 8,2 ± 1,5; p=0,006). However, the DM2-CAD group showed higher levels of plasmatic unesterified cholesterol (36,3±8,0 vs 33,6±6,5 ;p=0,02)....