ABSTRACT
BACKGROUND AND PURPOSE: Abdominal aortic aneurysm (AAA) is a degenerative vascular disease associated with angiogenesis. Bexarotene is a retinoid X receptor (RXR) ligand with anti-angiogenic activity. Statins also exert anti-angiogenic activity and activate PPARs. Because RXR ligands form permissive heterodimers with PPARs and a single anti-angiogenic drug may not be sufficient to combat the wide array of angiogenic factors produced during AAA, we evaluated the effect of combined low doses of bexarotene and rosuvastatin in a mouse model of AAA. EXPERIMENTAL APPROACH: The effect of the combined treatment was investigated in a murine model of angiotensin II-induced AAA in apoE(-/-) mice. This combination therapy was also evaluated in in vivo (Matrigel plug assay) and in vitro (endothelial cell differentiation assay) models of angiogenesis as well as the underlying mechanisms involved. KEY RESULTS: Co-treatment with bexarotene plus rosuvastatin reduced aneurysm formation, inflammation and neovascularization compared with each single treatment. In HUVEC, the combination of suboptimal concentrations of bexarotene and rosuvastatin inhibited angiotensin II-induced morphogenesis, proliferation and migration. These effects were accompanied by diminished production of pro-angiogenic chemokines (CXCL1, CCL2 or CCL5) and VEGF, and seemed to be mediated by RXRα/PPARα and RXRα/PPARγ activation. This combined therapy reduced the activation of members of the downstream PI3K pathway (Akt/mTOR and p70S6K1) in vivo and in vitro. CONCLUSIONS AND IMPLICATIONS: The combination of RXR agonists with statins at low doses synergistically interferes with the signalling pathways that modulate inflammation and angiogenesis and may constitute a new and safer therapeutic treatment for the control of AAA.
Subject(s)
Aortic Aneurysm, Abdominal/prevention & control , Apolipoproteins E/genetics , Rosuvastatin Calcium/pharmacology , Tetrahydronaphthalenes/pharmacology , Angiogenesis Inhibitors/administration & dosage , Angiogenesis Inhibitors/pharmacology , Angiotensin II/toxicity , Animals , Bexarotene , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Synergism , Human Umbilical Vein Endothelial Cells , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Inflammation/pathology , Inflammation/prevention & control , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Neovascularization, Pathologic/prevention & control , Phosphatidylinositol 3-Kinases/metabolism , Rosuvastatin Calcium/administration & dosage , Signal Transduction/drug effects , Tetrahydronaphthalenes/administration & dosageABSTRACT
AIMS: Retinal vein occlusion (RVO) is the most frequent retinal vascular disease after diabetic retinopathy in which arterial risk factors are much more relevant than venous factors. The objective was to evaluate the role of risk factors in the development of the first episode of RVO. SUBJECTS AND METHODS: One hundred patients with RVO [mean age 56 years, 42% females and mean body mass index (BMI) 27.5 kg/m(2)] were recruited consecutively from the outpatient clinic of a tertiary hospital in Valencia (Spain). All subjects underwent clinical assessment including anthropometric and blood pressure measurements and laboratory test including homocysteine, antiphospholipid antibodies (aPLAs) and thrombophilia studies. In half of the subjects, a carotid ultrasonography was performed. Three control populations matched by age, sex and BMI from different population-based studies were used to compare the levels and prevalence of arterial risk factors. One cohort of young patients with venous thromboembolic disease was used to compare the venous risk factors. RESULTS: Blood pressure levels and the prevalence of hypertension were significantly higher in the RVO population when compared with those for the general populations. There was also a large proportion of undiagnosed hypertension within the RVO group. Moreover, carotid evaluation revealed that a large proportion of patients with RVO had evidence of subclinical organ damage. In addition, homocysteine levels and prevalence of aPLAs were similar to the results obtained in our cohort of venous thromboembolic disease. CONCLUSIONS: The results indicate that hypertension is the key factor in the development of RVO, and that RVO can be the first manifestation of an undiagnosed hypertension. Furthermore, the majority of these patients had evidence of atherosclerotic disease. Among the venous factors, a thrombophilia study does not seem to be useful and only the prevalence of hyperhomocysteinaemia and aPLAs is higher than in the general population.
