Adenosine-induced cardiac gene expression of ischemic murine hearts revealed by cDNA array hybridization

Global gene expression profiling in the failing myocardium

Heart failure (HF) is a syndrome that involves multiple cellular mechanisms leading to a common phenotype of reduced ventricular contraction and cardiac chamber dilation. To clarify the mechanisms, a number of microarray analyses of the failing myocardium have been conducted. Gene expression profiles are usually compared between opposing pairs of samples, such as non-failing vs failing hearts, ischemic vs non-ischemic hearts, male vs female failing hearts or atria vs ventricles of failing hearts. Apart from these conventional methods, a different novel approach identified cardiac myosin light chain kinase (MLCK) as a HF-related gene by the comprehensive search for the genes that had an expression level that strongly correlated with the severity of HF; further investigations proved the important role of cardiac MLCK in HF. Moreover, a robust gene expression signature composed of 27 genes was revealed on analysis of 4 independent microarray data sets from the failing myocardium of dilated cardiomyopathy. The authors newly demonstrate 107 HF-related genes that were listed in 2 or more of 7 microarray data sets previously reported. Among these genes, many were observed to be involved in mitochondrial dysfunction and oxidative phosphorylation and 3 extracellular molecules, including periostin, pleiotrophin, and SERPINA3, which might become novel diagnostic and therapeutic targets for HF. These novel strategies warrant the new identification of specific genes that are linked to the pathophysiology of HF.

Plasma Adenosine Levels in Peri-Menopausal Women Having Frequent Hot Flushes

BACKGROUND

The effect of hormone replacement therapy (HRT) on plasma adenosine levels was investigated in climacteric women experiencing hot flushes.

METHODS AND RESULTS

Plasma adenosine levels were measured in 13 peri-menopausal women with frequent hot flushes (>5 per day) before and 3-4 months after initiating HRT. Thirteen healthy pre-menopausal, 9 peri-menopausal women with few hot flushes (<1 or 2 per day) and 10 healthy postmenopausal women were enrolled as controls. The average plasma adenosine level in the peri-menopausal women was 0.20+/-0.09 micromol/L, which was significantly higher than in the pre-menopausal (0.12+/-0.07 micromol/L, p<0.05), peri-menopausal with few hot flushes (0.10+/-0.09 micromol/L, p<0.05) and postmenopausal women (0.13+/-0.06 micromol/L, p<0.05). Both the increased adenosine level and the hot flushes were decreased by HRT (plasma adenosine: 0.13+/-0.06 micromol/L).

CONCLUSIONS

Increased plasma adenosine in peri-menopausal women may be associated with frequent hot flushes.

Acute adenosinergic cardioprotection in ischemic-reperfused hearts

Cells of the cardiovascular system generate and release purine nucleoside adenosine in increasing quantities when constituent cells are "stressed" or subjected to injurious stimuli. This increased adenosine can interact with surface receptors in myocardial, vascular, fibroblast, and inflammatory cells to modulate cellular function and phenotype. Additionally, adenosine is rapidly reincorporated back into 5'-AMP to maintain the adenine nucleotide pool. Via these receptor-dependent and independent (metabolic) paths, adenosine can substantially modify the acute response to ischemic insult, in addition to generating a more sustained ischemia-tolerant phenotype (preconditioning). However, the molecular basis for acute adenosinergic cardioprotection remains incompletely understood and may well differ from more widely studied preconditioning. Here we review current knowledge and some controversies regarding acute cardioprotection via adenosine and adenosine receptor activation.

Canine DNA array as a potential tool for combining physiology and molecular biology

The combining of molecular biology and physiology is essential for the further development of cardiovascular medicine, and DNA microarray is a useful tool for assessing multiple gene expressions. A canine DNA microarray has been designed and tested. Approximately 60 cardiovascular-related genes were cloned from newly developed canine cDNA libraries and spotted on slides. Using the arrays, the gene expression profiles of canine myocardium in were analyzed 2 protocols: (1). ischemic myocardium by 50% reduction of the coronary blood flow, and (2). necrotic myocardium caused by coronary artery ligation. Three hours after 50% flow reduction, cardiovascular-related genes, including ecto-5'-nucleotidase, endothelin-1, PAI-1, and AT receptors, exhibited rapid alteration and there were many more altered genes than with the complete coronary occlusion. Irreversible ischemic damage without necrosis more strongly affected gene expressions in surviving myocardium than in fatally damaged myocardium. The canine DNA microarray is a useful tool for assessing the precise molecular events following changes in the pathophysiological conditions of the heart.