Systemic hypertension augments, whereas insulin-dependent diabetes down-regulates, endothelin A receptor expression in the mammary artery in coronary artery disease patients.

BACKGROUND: Endothelin (ET) A receptor antagonism causes decreased vasodilation in hypertensive coronary arteries and decreased effects on coronary artery compliance in diabetic patients. METHODS: We investigate the mRNA expression of ET-1, ET(A) and ET(B) receptors, using real time RT-PCR, in biopsies from the internal mammary artery obtained from 49 patients, 18 diabetics and 34 hypertensives, all undergoing coronary artery bypass grafting. RESULTS: Hypertensive patients had higher ET-1 mRNA expression (16438 [8417, 23917]), than normotensive patients (2974 [2283, 18055], p=0.008). Diabetic patients had significantly lower ET(A) receptor levels than non-diabetic patients (455 [167, 1496] vs. 1660 [700, 3190], respectively, p = 0.003). CONCLUSIONS: Multivariate analysis demonstrated that the presence of systemic hypertension was the only independent predictor of log ET(A) receptor expression and log ET-1 expression, while insulin-dependent diabetes was negatively correlated with ET(A) receptor expression. ETB receptor expression was not correlated with any predictor. Systemic hypertension is associated with increased ET-1 and ET(A) receptor mRNA expression, whereas insulin-dependent diabetes down-regulates ET(A) receptor mRNA expression in the internal mammary artery in patients with coronary artery disease undergoing bypass grafting.

Endothelin system and atrial fibrillation post-cardiac surgery.

OBJECTIVE: We investigated the relation between the endothelin system and atrial fibrillation. BACKGROUND: Endothelin has been implicated in the pathophysiology of atrial fibrillation, but the exact role of A- and B-receptors is unknown. METHODS: We obtained right atrial biopsies from patients in sinus rhythm and preserved left ventricular function, undergoing off-pump coronary artery bypass grafting. The expression of endothelin, A- and B-receptors was measured using real time reverse-transcribed polymerase chain reaction. RESULTS: We studied 52 patients (45 male, mean age 66+/-1 years, mean ejection fraction 52+/-1%). During a 5-day post-operative period, persistent atrial fibrillation occurred in 15 patients (28.8%). Endothelin mRNA expression was comparable in patients who subsequently developed atrial fibrillation and in those maintaining sinus rhythm. However, the former group displayed down-regulation of endothelin A- (by approximately 60%, p=0.0059) and of B-receptors (by approximately 40%, p=0.0084). The decreased endothelin A-receptor expression could predict atrial fibrillation occurrence (Wilks lambda=0.86, F=6.16, p=0.017). CONCLUSION: Decreased endothelin A- and B-receptor expression is associated with atrial fibrillation after bypass surgery.

Expression profile of total VEGF, VEGF splice variants and VEGF receptors in the myocardium and arterial vasculature of diabetic and non-diabetic patients with coronary artery disease.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis and is implicated in the development of diabetic microvascular and macrovascular disease. METHODS: The expression of total VEGF, VEGF splice variants (VEGF(121), VEGF(145), VEGF(148), VEGF(165), VEGF(183) and VEGF(189)), VEGFR-1 and VEGFR-2, was investigated in biopsies from the right atrium and left internal mammary artery (LIMA) of 32 non-diabetic and 20 diabetic patients undergoing coronary artery bypass grafting. RESULTS: Diabetes was independently negatively correlated to total VEGF mRNA expression in atrium. Total VEGF, VEGF(121) and VEGF(165) mRNA levels were upregulated in the LIMA of diabetics vs. non-diabetics. The expression of VEGF receptors in atrium and LIMA was similar between these groups. VEGF(121) and VEGF(165) were the major variants expressed, followed by VEGF(189) and VEGF(183), while VEGF(148) and VEGF(145) were detected in small amounts. The expression profile of VEGF splice variants displayed significant heterogeneity between the examined tissues. CONCLUSIONS: This is the first study to quantify VEGF splice variants expression in cardiac and vascular tissue. Our results could help elucidate the role of VEGF splice variants in diabetic complications.

Quantitative real-time reverse transcription PCR study of the expression of vascular endothelial growth factor (VEGF) splice variants and VEGF receptors (VEGFR-1 and VEGFR-2) in non small cell lung cancer.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a major regulator of angiogenesis and its expression is increased in non-small cell lung cancer (NSCLC). We aimed to determine the expression pattern of VEGF splice variants in NSCLC and its correlation with the clinicopathological characteristics of tumors. METHODS: We used real-time reverse transcription PCR to quantify the mRNA expression of total VEGF, 4 VEGF splice variants (VEGF(121), VEGF(165), VEGF(183), and VEGF(189)), and 2 VEGF receptors (VEGFR-1 and VEGFR-2) in 27 pairs of cancerous and adjacent noncancerous tissues originating from patients with NSCLC. RESULTS: Total VEGF, VEGF(121), and VEGF(165) were expressed in all specimens, whereas VEGF(183) and VEGF(189) were present in small amounts in certain samples. Total VEGF, VEGF(121), and VEGF(165) mRNA was upregulated in cancerous compared with healthy tissues, whereas VEGF(183) and VEGF(189) expression tended to be higher in healthy tissues. The expression of VEGFRs was similar between matched specimens. No correlation was found between the expression of total VEGF or VEGF splice variants and the clinicopathological characteristics of tumors. The expression patterns of VEGF splice variants differed between tissue pairs. VEGF(121) was the major variant expressed in all samples; however, its relative expression was higher in cancerous tissues. The relative expression of VEGF(183) and VEGF(189) was upregulated in healthy lung tissues, whereas the ratio of VEGF(165) to total VEGF was similar between matched specimens. CONCLUSIONS: The expression pattern of certain VEGF splice variants is altered during tumorigenesis. Our data support the hypothesis that during malignant progression an angiogenic switch favoring the shorter diffusible isoforms occurs.

Development and applications of a real-time quantitative RT-PCR method (QRT-PCR) for BRCA1 mRNA.

OBJECTIVES: To develop a real-time quantitative RT-PCR method for BRCA1 mRNA and then use it for the study of BRCA1 gene expression in human MCF-7 breast cancer cells after their exposure to antineoplastic agents and gamma irradiation. DESIGN AND METHODS: The developed QRT-PCR method is based on the real-time monitoring of a fluorescein-labeled TaqMan probe, specific for BRCA1 mRNA, during PCR in the LightCycler. A BRCA1 PCR amplicon was purified, quantitated and used as a standard of known concentration for the development and analytical evaluation of the assay. The method was applied to study the alteration of BRCA1 gene expression after exposure to taxol, doxorubicin, 5-fluorouracil, etoposide or gamma irradiation in human MCF-7 breast cancer cells. RESULTS: The developed method is quantitative, highly specific for mRNA and highly sensitive (detection limit of 4 BRCA1 copies per mug of total RNA). We observed a reduction of BRCA1 expression for all antineoplastic agents used, while the gamma irradiated MCF-7 cells had an increase of expression with a peak at the 10 Gy dose. CONCLUSIONS: The developed BRCA1 QRT-PCR method is quantitative, highly sensitive and specific. The proposed method is rapid, automated, and cost effective and can be used to study BRCA1 expression in a variety of clinical samples.