Plasma profiling by a protein array approach identifies IGFBP-1 as a novel biomarker of abdominal aortic aneurysm.

OBJECTIVE: Cytokines are important mediators of immune-inflammatory responses implicated in abdominal aortic aneurysm (AAA) pathogenesis. Our objective was to investigate the cytokine expression profile in plasma of AAA patients. METHODS: Cytokine protein expression was measured in plasma of 5 large AAA patients (aortic size >50mm) and 5 controls (aortic size <30 mm) using a 20-cytokine antibody-based protein array. IGFBP-1 plasma concentrations were analyzed by ELISA. IGFBP-1 protein levels were analyzed in AAA thrombus by immunohistochemistry and Western blot. Platelet aggregation was assessed by conventional optical aggregometry. RESULTS: Several proteins including MIP-3 alpha (CCL20), Eotaxin-2 and IGFBP-1 were increased in AAA patients compared to controls. Among them, IGFBP-1 concentrations were significantly higher in large AAA patients vs control subjects. These data were validated in plasma of patients with large AAA (n = 30) compared to matched controls (n = 30) [834(469-1628) vs 497(204-893) pg/ml, p<0.01]. Furthermore, the potential association of IGFBP-1 with AAA size was analyzed in a second independent group of subjects [large AAA (n = 59), small AAA patients (aortic size = 30-50mm, n = 54) and controls (n = 30)]. Interestingly, IGFBP-1 levels correlated with AAA size (r = 0.4, p<0.001), which remained significant after adjusting for traditional risk factors. IGFBP-1 was localized in the luminal part of AAA thrombus and IGFBP-1 levels were increased in AAA thrombus conditioned media compared to media layer and healthy media. Interestingly, IGFBP-1 abrogated the potentiation of ADP-induced platelet aggregation triggered by IGF-1. CONCLUSIONS: IGFBP-1 has been identified by a protein array approach as a potential novel biomarker of AAA. The biological role of IGFBP-1 in AAA pathogenesis could be related to the modulation on the effect of IGF-1 on platelet aggregation.

Insulin-like growth factor I - a novel biomarker of abdominal aortic aneurysms.

OBJECTIVE: The study aimed to test the potential role of insulin-like growth factor I (IGF-I) and IGF-II as biomarkers for abdominal aortic aneurysm (AAA). METHODS AND RESULTS: IGF-I and II levels were analysed in 115 patients with screening diagnosed AAA kept under annual surveillance for 10 years. Serum IGF-I correlated positively with AAA size and growth rate (r = 0.23, P = 0.016 and r = 0.27, P = 0.004), persisting after adjustment for potential confounders. Serum IGF-I level predicted cases needing later surgery (AOC: 0.63; 95% confidence interval: 0.52-0.73). CONCLUSIONS: In this prospective, long-term study, baseline serum IGF-I correlated positively with AAA size and growth rate and predicted future need for preventive surgery.

Increased levels of thioredoxin in patients with abdominal aortic aneurysms (AAAs). A potential link of oxidative stress with AAA evolution.

OBJECTIVE: Oxidative stress is a main mechanism involved in vascular pathologies. Increased thioredoxin (TRX) levels have been observed in several oxidative stress-associated cardiovascular diseases. We aim to test the potential role of TRX as a biomarker of oxidative stress in abdominal aortic aneurysm (AAA). METHODS: TRX levels were analysed in both AAA intraluminal thrombus (ILT) tissue and in tissue-conditioned media by immunohistochemistry, Western blot and ELISA. Moreover, serum TRX levels were assessed in AAA Caucasian patients by ELISA. RESULTS: TRX was mainly localized in the luminal part of ILT in AAA. Compared with the abluminal layer, TRX release was increased in the luminal layer of the ILT of AAA (31+/-9 ng/ml vs. 9+/-3 ng/ml, p<0.05). The interest of this approach is that we can identify proteins potentially released into the blood compartment, which could serve as biomarkers of the pathology. In a training population, serum TRX levels were significantly increased in patients with AAA relative to healthy subjects (50+/-6 ng/ml vs. 26+/-3 ng/ml, p<0.05). These results were validated in a second independent group of patients. Moreover, a positive correlation between TRX and AAA size (rho=0.5, p<0.001) was observed. Finally, in AAA samples with follow-up, TRX was positively associated to aneurismal growth rate (rho=0.25, p=0.027). CONCLUSIONS: TRX release is increased in the luminal part of AAA and TRX serum levels are increased in AAA patients compared with healthy subjects. TRX levels correlates with AAA size and expansion, suggesting its potential role as a biomarker of AAA evolution.

Aspectos proteómicos y genéticos de la resistencia a la aspirina / Proteomics and genetics aspects of aspirin resistance

Objetivo: Analizar si existe alguna asociación entre la resistencia a aspirina (RA) y la presencia de polimorfismos genéticos de un único nucleótido (SNPs) en el gen de la COX-1, así como su relación con modificaciones en la expresión de proteínas plasmáticas en pacientes con enfermedad isquémica estable y tratamiento continuado de aspirina. Materiales y métodos: Analizamos el proteoma plasmático de 19 pacientes sensibles, 19 resistentes. RA se definió mediante el sistema PFA-100. Se realizó electroforesis bidimensional (IPG 17cm, pH(4-7), geles SDS-PAGE 10%) y tinción con plata. Se analizaron cambios en tres SNPs (A-842G, C22T y C50T) en 50 pacientes sensibles, 33 resistentes y 83 controles mediante PCR a tiempo real. Resultados: La expresión de cuatro isoformas de alfa1-antitripsina estaba aumentada en los pacientes resistentes. No encontramos diferencias en la expresión de ceruloplasmina, precursor de haptoglobina, apolipoproteína AI y precursor de albúmina entre ambos tipos de pacientes. Ningún paciente presentó cambios en el SNP A-842G. La frecuencia de cambio en C22T y C50T fue relativamente baja con respecto a la población total. Conclusiones: No encontramos asociación entre la presencia de polimorfismos en el gen de la COX-1 y la peor respuesta a la aspirina. Los cambios en observados alfa1-antitripsina podrían estar relacionados con un diferente estado inflamatorio entre ambos tipos de pacientes (AU)

Aim: To evaluate the existence of a possible association between Aspirin resistance (AR), COX-1 single-nucleotide polymorphisms (SNPs) and the modifications in the plasma proteome of clinically stable coronary patients. Materials and methods: AR was defined according to the PFA-100 assay. AR-sensitive and AR-resistant patients had been taken aspirin for the last 9 months. The proteomic study (19 AR-sensitive, 19 AR-resistant) was performed using IPG strips (17cm, pH 4-7), SDS-PAGE gels (10%) and silver staining. We study three SNPs (A- 842G, C22T y C50T) in 50 AR-sensitive patients, 33 AR-resistant and 83 controls using a real-time PCR. Results: The expression of four alpha1-antitripsin isoforms was increased in the aspirin-resistant patients. No differences were found in the expression of ceruloplasmin, haptoglobin-precursor, apolipoprotein-AI and albumin- precursor between both groups of patients. The A-842G SNP was undetectable in all subjects. The remaining two SNPs (C22T y C50T) showed a low frequency with respect the global population. Conclusions: The low SNPs frequencies were unlikely to explain the difference in aspirin responsiveness between both groups of patients. The changes in alpha1-antitripsin could be linked with a different inflammatory state in these patients (AU)