With regard to blood pressure, EREx rats had lower SBP levels than 16-week HFD (P<0.001) or ER (P=0.002) rats. (VEGFR) 1 and 2, Ang1, Ang2 and Tie2) and semiquantification of VEGF, VEGFR1, VEGFR2, Ang1, Ang2, Tie2, endothelial nitric oxide synthase (eNOS) and Akt/phospho-Akt by Western blotting. HF diet-fed rats exhibited lower high-density lipoprotein cholesterol (HDL-c) levels, higher systolic blood pressure and an increased atherogenic index. A significant increase in Ang2 expression in the CC was verified and coupled to a decrease in VEGF and VEGFRs. The Akt pathway was activated by the HF diet. Energy restriction and exercise increased eNOS expression and restored most HF diet-induced modifications except for VEGFR2 expression. These results emphasize the role of diet on vascular function regulation, demonstrating that cavernous imbalance of VEGF/VEGFRs and Angs/Tie2 systems occurs before serum lipid changes and obesity onset, antedating structural atherosclerotic features. Keywords:angiopoietins, corpus cavernosum, endothelial dysfunction, energy restriction, exercise, high-fat diet, VEGF == Introduction == Erectile dysfunction (ED) affects more than 152 million men worldwide1and often manifests in patients with vascular disease.2Moreover, ED is frequently associated with metabolic disturbances such as diabetes, atherogenic dyslipidemia and visceral obesity.3These disorders constitute major risk factors for endothelial dysfunction, a condition that precedes the earliest clinical manifestations of atherosclerosis.4Endothelial dysfunction is characterized by a deficient URMC-099 synthesis of nitric oxide (NO),4which results in impairment of endothelium-dependent smooth muscle relaxation and an inability to maintain penile erection.5Therefore, several authors consider endothelial dysfunction equivalent to ED.6 It is well established that chronic consumption of a high-fat (HF) diet strongly favours endothelial dysfunction.7However, the exact mechanism through which this dietary pattern contributes to the onset and progression of ED is not fully understood. Recent evidence suggests that HF diets induce secretion of pro-inflammatory molecules and cause an imbalance of expression of angiogenic factors, which together contribute to endothelial damage.8Furthermore, the impairment of endothelial function in HF feeding conditions decreases NO synthase activity, contributing Rabbit Polyclonal to MAP3K8 (phospho-Ser400) to increase oxidative stress and decrease NO bioavailability.9In fact, the reduction in endothelial NO synthase (eNOS) expression is considered one of the main mechanisms that leads to endothelial dysfunction and, consequently, to atherogenesis.10,11 Vascular maintenance and repair in the corpus cavernosum (CC) is under the control of multiple angiogenic factors. Vascular endothelial growth factor (VEGF), a key angiogenic factor that regulates angiogenesisin vivo,12binds to the high-affinity tyrosine kinase membrane receptors, VEGF receptor (VEGFR) 1 and 2. VEGFR2 activation is responsible for most of the angiogenic properties of VEGF.13Furthermore, VEGF crosstalksin vivowith other angiogenic molecules, such as angiopoietins (Ang).14Ang1 and Ang2 are natural antagonists that compete for binding to their specific receptor, Tie2 (tyrosine-kinase with immunoglobulin-like loop and EGF homology domains).14Ang1 cooperates with VEGF in the stabilisation of vasculature, promoting interactions between endothelial cells (ECs) and mural cells, and the extracellular matrix.14On the other hand, Ang2, whose activity is tissue-specific, is involved in vessel growth and remodelling when sufficient VEGF is available.15In contrast, in the absence/inhibition of VEGF, Ang2 destabilizes pre-existing vasculature.16 The aim of this study was to evaluate the effect of a chronic intake of an HF diet on the expression of VEGF, angiopoietins and their transduction pathways in rat CC and whether it might be modified by energy restriction and exercise. As far as we know, this is the first study of VEGF/VEGFRs and Ang/Tie2 pathways in rat cavernous tissue under nutritionally defined conditions. It is our conviction that a better understanding of nutritional effects on cellular and molecular mechanisms involved in penile endothelial function and/or remodelling regulation will disclose new preventive and therapeutic approaches for ED. == Materials and methods == == Animals == All animal procedures were undertaken according to the European Community Guidelines (86/609/EEC) and the Portuguese Act (129/92) for the use of experimental animals. Adult male Wistar rats (8 weeks old,n=42) weighing 287.929.8 g (s.d.), obtained from the colony of the Instituto de Biologia Molecular e Celular da Universidade do Porto, were individually housed with free access to tap water URMC-099 and maintained under standard laboratory conditions (controlled URMC-099 12-h light/dark cycle; 2022 C temperature; 40%60% humidity). Animals had free access to a purified rodent diet with 45% of energy supplied by URMC-099 fat (#58V8 TestDiet, Purina Mills; LLC/PMI Nutrition International, Richmond, VA, USA), for 8 or 16 weeks (8- and 16-week HF diet (HFD) group,n=18 andn=12, respectively). After 8 weeks of the HF diet, groups of six randomly selected rats were subjected for an 8-week period to either energy restriction (the ER group,n=6) or energy restriction associated with exercise (the EREx group,n=6). These.