Cerivastatin represses atherogenic gene expression through the induction of KLF2 via isoprenoid metabolic pathways.

Earlier clinical studies have reported that cerivastatin has an anti-atherosclerotic effect that is unique among the statins. In our study, human THP-1 macrophage cells were used to study the effects of various statins on the expressions of the atherosclerotic genes and Kruppel-like factor 2 (KLF2). Cerivastatin significantly inhibited the two atherosclerotic genes, monocyte chemoattractant protein-1 (MCP-1) and C-C chemokine receptor type 2 (CCR2) at both the mRNA and protein levels, while the other statins did not. Accordingly, cerivastatin was also the most potent inducer of KLF2 transcription in the macrophages. An siRNA-induced reduction in KLF2 expression blocked the inhibition of MCP-1 and CCR2 by cerivastatin. When the cells were further treated with mevalonate, farnesylpyrophosphate (FPP) or geranylgeranyl pyrophosphate (GGPP), the effects of cerivastatin on KLF2, MCP-1 and CCR2 were obviously reversed. Thus, the results showed that cerivastatin was a potent inhibitor of the inflammation genes MCP-1 and CCR2 through the induction of KLF2. The regulation of MCP-1, CCR2 and KLF2 by cerivastatin was isoprenoid pathway dependent. Our studies suggest that the effect of cerivastatin on atherosclerotic genes and KLF2 expression may contribute to the cardioprotection observed in reported clinical studies.

Comparing homatropine and atropine in pediatric cycloplegic refractions.

PURPOSE: To compare cycloplegic efficacy of homatropine and atropine in pediatric refractions and derive a regression formula to calculate refraction findings for both agents. METHODS: Children between the ages of 4 to 10 years with refractive error underwent cycloplegic refraction with 2% homatropine and 1% atropine by retinoscopy and automated refraction. Refractive data were compared by the use of power vector analysis. Primary outcome measures were spherical equivalent (SE), astigmatic components of refractive error (J(0) and J(45)), overall blur strength of refractive error, and residual accommodation. RESULTS: A total of 63 children with refractive error were enrolled (mean age, 6.7 ± 1.6 years). Compared with homatropine, atropine uncovered significantly greater hyperopic SE in patients with hypermetropia (4.2 ± 2.5 D [atropine] vs 3.5 ± 2.3 D [homatropine]; P < 0.001) as well as myopia (-1.8 ± 1.4 D [atropine] vs -2.1 ± 1.4 D [homatropine]; P < 0.001). Overall blur strength was significantly greater with atropine (3.1 ± 2.1 [atropine] vs 2.9 ± 1.9 [homatropine]; P = 0.003). Homatropine had a significantly greater residual accommodation (1.8 ± 0.4 D [atropine] vs 3.1 ± 0.5 D [homatropine]; P < 0.001). A regression formula was derived. CONCLUSIONS: Of the 2 cycloplegic agents, atropine yielded more consistent results than homatropine; however atropine had a relatively slow onset and prolonged effect. Our regression formula may make it possible to derive atropine-like results while using the clinically more versatile homatropine.

Dimethylarginine dimethylaminohydrolase: a new therapeutic target for the modulation of nitric oxide and angiogenesis.

Nitric oxide (NO) has a key role in promoting angiogenesis by increasing vasodilation, vascular permeability, endothelial cell proliferation and migration, and by modifying the activities of angiogenic mediators. NO is also critical for the mobilization of endothelial progenitor cells from the bone marrow which promotes vasculogenesis and angiogenesis. Studies have shown that the enzymes catalyzing NO synthesis are inhibited by the endogenously generated inhibitor asymmetric dimethylarginine (ADMA). Pharmacological agents targeted to modulate dimethyl-arginine dimethylaminohydrolase, the key enzyme metabolizing ADMA, may offer a potential strategy for developing novel pro- and anti-angiogenic therapies.

Selective regulation of arterial branching morphogenesis by synectin.

Branching morphogenesis is a key process in the formation of vascular networks. To date, little is known regarding the molecular events regulating this process. We investigated the involvement of synectin in this process. In zebrafish embryos, synectin knockdown resulted in a hypoplastic dorsal aorta and hypobranched, stunted, and thin intersomitic vessels due to impaired migration and proliferation of angioblasts and arterial endothelial cells while not affecting venous development. Synectin(-/-) mice demonstrated decreased body and organ size, reduced numbers of arteries, and an altered pattern of arterial branching in multiple vascular beds while the venous system remained normal. Murine synectin(-/-) primary arterial, but not venous, endothelial cells showed decreased in vitro tube formation, migration, and proliferation and impaired polarization due to abnormal localization of activated Rac1. We conclude that synectin is involved in selective regulation of arterial, but not venous, growth and branching morphogenesis and that Rac1 plays an important role in this process.

Experiments with nitric oxide synthase inhibitors in spinal nerve ligated rats provide no evidence of a role for nitric oxide in neuropathic mechanical allodynia.

We have investigated the effect of treatment with N(omega)-nitro-l-arginine methylester (l-NAME), a non-selective nitric oxide synthase inhibitor (NOS), both before and after the induction of mechanical allodynia by tight ligation of the left L5 and L6 spinal nerves in rats (SNL rats). The degree of mechanical allodynia was measured by tactile threshold for paw flinching with von Frey filaments. Intraperitoneal (i.p.) administration of l-NAME (3-30 mg/kg) 1 week after the spinal nerve ligation produced a dose-dependent reduction of the behavioral signs of mechanical allodynia, but the effect was not reversed by pretreatment with l-arginine (300 mg/kg). N(omega)-Nitro-l-arginine (l-NNA, i.p., 30 mg/kg), aminoguanidine (AG, i.p., 30 mg/kg) and a potent neuronal NOS inhibitor (LY457963, i.p., 30 mg/kg) did not reduce mechanical sensitivity in the SNL rats. Furthermore, using an ex vivo NOS activity assay, l-NAME partially inhibited the spinal NOS activity, whereas LY457963 almost completely inhibited the spinal NOS activity. Prior administration of l-NAME (i.p., 30 mg/kg) or of MK-801 (0.5 mg/kg), an NMDA antagonist, 30 min before the spinal nerve ligation significantly prevented the development of mechanical allodynia after spinal nerve ligation for an extended period of time. High doses of l-arginine (100 mg/kg or 300 mg/kg, i.p.), however, did not reverse the preemptive effect of l-NAME. These results suggest that neither the anti-allodynic nor the preemptive effects of l-NAME are mediated by NOS inhibition.

Identification of a novel selective peroxisome proliferator-activated receptor alpha agonist, 2-methyl-2-(4-{3-[1-(4-methylbenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl]propyl}phenoxy)propanoic acid (LY518674), that produces marked changes in serum lipids and apolipoprotein A-1 expression.

Low high-density lipoprotein-cholesterol (HDL-c) is an important risk factor of coronary artery disease (CAD). Optimum therapy for raising HDL-c is still not available. Identification of novel HDL-raising agents would produce a major impact on CAD. In this study, we have identified a potent (IC50 approximately 24 nM) and selective peroxisome proliferator-activated receptor alpha (PPARalpha) agonist, 2-methyl-2-(4-{3-[1-(4-methylbenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl]propyl}phenoxy)propanoic acid (LY518674). In human apolipoprotein A-1 (apoA-1) transgenic mice, LY518674 produced a dose-dependent increase in serum HDL-c, resulting in 208 +/- 15% elevation at optimum dose. A new synthesis of apoA-1 contributed to the increase in HDL-c. LY518674 increased apoA-1 mRNA levels in liver. Moreover, liver slices from animals treated with LY518674 secreted 3- to 6-fold more apoA-1 than control liver slices. In cultured hepatocytes, LY518674 produced 50% higher apoA-1 secretion, which was associated with increase in radiolabeled methionine incorporation in apoA-1. Thus, LY518674 is a potent and selective PPARalpha agonist that produced a much greater increase in serum HDL-c than the known fibrate drugs. The increase in HDL-c was associated with de novo synthesis of apoA-1.

Staurosporine promotes endothelial cell assembly and FAK phosphorylation during in vitro angiogenesis.

In the present study, we report that staurosporine, a known PKC inhibitor, enhanced in vitro angiogenesis. Endothelial cells plated in a three-dimensional matrix formed cords and enclosed structures within 4-6 hours. The cells in cord structures became elongated during the subsequent incubation. Tube formation was confirmed by confocal microscopy. Addition of VEGF enhanced the early responses of endothelial cells, leading to enhanced formation of cords. Staurosporine unexpectedly also enhanced the early endothelial responses, leading to faster alignment of cells and assembly into tube-like structures. At concentrations inhibitory to endothelial cell PKC activity, staurosporine produced 91% and 203% increases in the number of cords and the enclosed structures, respectively, as compared to the controls. Other selective inhibitors of PKC did not stimulate in vitro angiogenesis in the absence or presence of VEGF. Further investigation showed that inhibition of PI-3 kinase and Raf-1 significantly reduced the effects of staurosporine. Staurosporine-induced in vitro angiogenesis required integrins alpha2 and alphavbeta3 and was associated with significantly enhanced FAK phosphorylation. These data indicate that staurosporine enhances in vitro angiogenesis by a means unrelated to its PKC inhibition. The data suggest that enhancement of in vitro angiogenesis by staurosporine involves integrin-mediated signaling, including the stimulation of FAK phosphorylation.

Pharmacological revascularisation in coronary and peripheral vascular disease.

Therapeutic angiogenesis is a novel approach to the treatment of ischaemic or occlusive coronary and peripheral vascular disease. The therapeutic concept is based on the restoration of distal blood flow by the enlargement of existing vessels and tissue perfusion by the induction of new capillaries. Initial studies have focused on the direct application of endothelial growth factors, vascular endothelial growth factor and fibroblast growth factor, or the delivery of genes using either a plasmid or adenoviral vector. Recently, new angiogenic agents such as hypoxia inducible factor-1alpha, fibroblast growth factor-4, Del-1 and hepatocyte growth factor have entered clinical testing. Moreover, stem-cell therapy or factors mobilising bone marrow progenitor cells have provided evidence for a new avenue for therapeutic angiogenesis. Numerous preclinical studies and several initial clinical trials have provided encouraging data in support of the feasibility of promoting biological revascularisation by the administration of angiogenic factors or cells.