Background
Secretoneurin is a neuropeptide located in nerve fibers along blood vessels, is up-regulated by hypoxia and induces angiogenesis. We tested the hypothesis that secretoneurin gene therapy exerts beneficial effects in a rat model of myocardial infarction and evaluated the mechanism of action on coronary endothelial cells.
Methods and Results
In-vivo secretoneurin improved left ventricular function, inhibited remodeling and reduced scar formation. In the infarct border zone secretoneurin induced coronary angiogenesis as shown by increased density of capillaries and arteries. In-vitro secretoneurin induced capillary tubes, stimulated proliferation, inhibited apoptosis and activated Akt and ERK in coronary endothelial cells. Effects were abrogated by a VEGF-antibody and secretoneurin stimulated VEGF receptors in these cells. Secretoneurin furthermore increased binding of VEGF to endothelial cells and binding was blocked by heparinase indicating that secretoneurin stimulates binding of VEGF to heparan sulfate proteoglycan binding sites. Additionally, secretoneurin increased binding of VEGF to its co-receptor neuropilin 1. In endothelial cells secretoneurin also stimulated FGF receptor-3 and IGF-1 receptor and in coronary vascular smooth muscle cells we observed stimulation of VEGF receptor-1 and FGF receptor-3. Exposure of cardiac myocytes to hypoxia and ischemic heart after myocardial infarction revealed increased secretoneurin m-RNA and protein.
Conclusions
Our data show that secretoneurin acts as an endogenous stimulator of VEGF signaling in coronary endothelial cells by enhancing binding of VEGF to low affinity binding sites and neuropilin 1 and stimulates further growth factor receptors like FGF receptor-3. Our in-vivo findings indicate that secretoneurin might be a promising therapeutic tool in ischemic heart disease.
SummaryCholesterol metabolism is closely interrelated with cardiovascular disease in humans. Dietary supplementation with omega-6 polyunsaturated fatty acids including arachidonic acid (AA) was shown to favorably affect plasma LDL-C and HDL-C. However, the underlying mechanisms are poorly understood. By combining data from a GWAS screening in >100,000 individuals of European ancestry, mediator lipidomics, and functional validation studies in mice, we identify the AA metabolome as an important regulator of cholesterol homeostasis. Pharmacological modulation of AA metabolism by aspirin induced hepatic generation of leukotrienes (LTs) and lipoxins (LXs), thereby increasing hepatic expression of the bile salt export pump Abcb11. Induction of Abcb11 translated in enhanced reverse cholesterol transport, one key function of HDL. Further characterization of the bioactive AA-derivatives identified LX mimetics to lower plasma LDL-C. Our results define the AA metabolome as conserved regulator of cholesterol metabolism, and identify AA derivatives as promising therapeutics to treat cardiovascular disease in humans.
The dacryocystitis in adults is mainly caused by postsaccal stenosis of the lacrimal ducts. The banking up of the lacrimal fluid leads to an accumulation of germs and following infection. This report describes the clinical and microbiological findings in a large consecutive series of patients that presented at the outpatient clinic of the 2nd Department of Ophthalmology of the University of Vienna with the signs of acute, chronic recurrent or chronic infections of the lacrimal system between 1983 and the end of 1990. Within the bacterial genus Staphylococci (S. aureus, S. epidermidis and S. saprophyticus) were the most frequently isolated organisms (74 cultures = 50% out of samples with positive cultures). It was quite interesting that a significant number of gram-negative rods (37 = 25.5%) could be isolated. Of these microorganisms Escherichia coli was most frequently growing on special media (17 cases = 11.7%) when cultures were obtained from acute inflamed lacrimal sacs of patients who suffered from chronic recurrent infections. Conservative therapy of purulent dacryocystitis constitutes the last possible preparation for a necessary surgical intervention and therefore the authors want to point out the importance of microbiological examinations so as to optimize antibiotic therapy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.