Changes In Endothelial Expression Research Articles

In vivo antivascular endothelial growth factor treatment induces corneal endothelium apoptosis in rabbits through changes in p75NTR-proNGF pathway.

Intravitreal injection (IVT) of antivascular endothelial growth factor (anti-VEGF) agents is widely used for the treatment of retinal vascular diseases. Recently, the injection of anti-VEGF agents in the ocular anterior chamber has been proposed for the treatment of neovascular glaucoma and potential side effects on the corneal structures have been investigated with contrasting results. Increasing evidence has demonstrated that VEGF inhibition is associated with cellular apoptotic changes and that this effect may be mediated by alterations in nerve growth factor (NGF) pathway. In this study, we demonstrated that anterior chamber injection (IC), but not IVT injection of two different anti-VEGF agents, aflibercept and ranibizumab, affects rabbit corneal endothelium in terms of survival and apoptosis andis associated with changes in endothelial expression of NGF precursor (proNGF) and p75 neurotrophin receptor (p75NTR) receptor.We observed an increase in corneal endothelial cell incorporation of trypan blue and expression of cleaved-caspase 3 (c-Casp3), p75NTR, and RhoA after IC injection of both anti-VEGF drugs when compared with the vehicle. Our results showed that apoptosis induction by aflibercept was more pronounced when compared with that of ranibizumab. Aflibercept also mediated a significant increase in endothelial expression of proNGF when compared with the vehicle. In line with these data, IC administration of both anti-VEGF agents induced the activation of apoptotic signals in endothelial cells, including an increase in c-Casp3, decrease in Bad Ser 112 phosphorylation, and unbalance of AKT phosphorylation.These results demonstrated that administration of anti-VEGF in the anterior chamber of rabbit affects endothelial cell survival by inducing apoptosis through alteration of NGF pathway.

Molecular Responses of Human Retinal Cells to Infection with Dengue Virus

Recent clinical reports indicate that infection with dengue virus (DENV) commonly has ocular manifestations. The most serious threat to vision is dengue retinopathy, including retinal vasculopathy and macular edema. Mechanisms of retinopathy are unstudied, but observations in patients implicate retinal pigment epithelial cells and retinal endothelial cells. Human retinal cells were inoculated with DENV-2 and monitored for up to 72 hours. Epithelial and endothelial cells supported DENV replication and release, but epithelial cells alone demonstrated clear cytopathic effect, and infection was more productive in those cells. Infection induced type I interferon responses from both cells, but this was stronger in epithelial cells. Endothelial cells increased expression of adhesion molecules, with sustained overexpression of vascular adhesion molecule-1. Transcellular impedance decreased for epithelial monolayers, but not endothelial monolayers, coinciding with cytopathic effect. This reduction was accompanied by disorganization of intracellular filamentous-actin and decreased expression of junctional molecules, zonula occludens 1, and catenin-β1. Changes in endothelial expression of adhesion molecules are consistent with the retinal vasculopathy seen in patients infected with DENV; decreases in epithelial junctional protein expression, paralleling loss of integrity of the epithelium, provide a molecular basis for DENV-associated macular edema. These molecular processes present potential therapeutic targets for vision-threatening dengue retinopathy.

Nitric Oxide‐Induced Changes in Endothelial Expression of Phosphodiesterases 2, 3, and 5

To investigate nitric oxide (NO)-mediated changes in expression of cyclic nucleotide degrading phosphodiesterases 2A (PDE2A), PDE3B, and PDE5A in human endothelial cells. Nitric oxide induces production of cyclic guanosine monophosphate (cGMP), which along with cyclic adenosine monophosphate (cAMP) is degraded by PDEs. NO donors and selective inhibitors of PDE3 and PDE5 induce migraine-like headache and play a role in endothelial dysfunction during stroke. The current study investigates possible NO modulation of cGMP-related PDEs relevant to headache induction in a cell line containing such PDEs. Real time polymerase chain reaction and Western blots were used to show expression of PDE2A, PDE3B, and PDE5A in a stable cell line of human brain microvascular endothelial cells. Effects of NO on PDE expression were analyzed at specific time intervals after continued DETA NONOate administration. This study shows the expression of PDE2A, PDE3B, and PDE5A mRNA and PDE3B and PDE5A protein in human cerebral endothelial cells. Long-term DETA NONOate administration induced an immediate mRNA up-regulation of PDE5A (1.9-fold, 0.5 hour), an early peak of PDE2A (1.4-fold, 1 and 2 hours) and later up-regulation of both PDE3B (1.6-fold, 4 hours) and PDE2A (1.7-fold, 8 hours and 1.2-fold after 24 hours). Such changes were, however, not translated into significant changes in protein expression indicating few, if any, functional effects. Long-term NO stimulation modulated PDE3 and PDE5 mRNA expression in endothelial cells. However, PDE3 and PDE5 protein levels were unaffected by NO. The presence of PDE3 or PDE5 in endothelial cells indicates that selective inhibitors may have functional effects in such cells. A complex interaction of cGMP and cAMP in response to NO administration may take place if the mRNA translates into active protein. Whether or not this plays a role in the headache mechanisms remains to be investigated.

The changes in the endothelial expression of cell adhesion molecules and iNOS in the vessel wall after the short-term administration of simvastatin in rabbit model of atherosclerosis

Cell adhesion molecules P-selectin, VCAM-1 and ICAM-1 play an important role in the pathogenesis of atherosclerosis. High levels of nitric oxide (NO) produced by inducible NO synthase (iNOS) have been associated with atherosclerotic processes. Simvastatin is an HMG-CoA reductase inhibitor responsible for many clinical benefits. The aim of this study was to detect and quantify changes in endothelial expression of P-selectin, VCAM-1, ICAM-1 and iNOS in the vessel wall after the shortterm administration of simvastatin in a rabbit model of atherosclerosis. Eighteen New Zealand White rabbits were randomly divided into three groups (n=6). In the cholesterol group, rabbits consumed an atherogenic diet (0.4% cholesterol) for eight weeks. In the simvastatin group, rabbits consumed an atherogenic diet for six weeks and then consumed an atherogenic diet supplemented with simvastatin (10 mg kg(-1)) for two weeks. Biochemical analysis showed that administration of simvastatin led to an almost two-fold lowering of the total serum cholesterol, VLDL, LDL and HDL, but not triglycerides, compared with the cholesterol-fed rabbits only. Stereological analysis of the immunohistochemical staining revealed that administration of simvastatin (10 mg kg(-1) daily) in an atherogenic diet decreased the endothelial expression of P-selectin, ICAM-1 and iNOS in both aortic arch and carotid artery compared with the cholesterol fed-rabbits only. We conclude that simvastatin has beneficial effects on endothelial function by decreasing expression of P-selectin, ICAM-1 and iNOS in endothelial cells in the very early stages of atherogenesis.

Injury of the Blood Brain Barrier and Up-Regulation of ICAM-1 in Polymicrobial Sepsis

The pathogenesis and mechanisms of septic encephalopathy are not completely understood. We compared two different models of sepsis: lipopolysaccharide-induced endotoxemia and cecal ligation and puncture (CLP) bacteremia in rats with respect to changes in endothelial expression of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1), platelet-endothelial cell adhesion molecule-1 (PECAM-1), and of cerebral albumin extravasation as a marker for capillary breakdown of the blood brain barrier. Male Wistar rats were divided into control, endotoxemia, or CLP-group. Mean arterial blood pressure was measured via femoral artery catheterization. Brain tissue for immunohistochemistry was harvested at 1 h, 6 h, and 24 h after induction of sepsis. The CLP-group showed a decrease in mean arterial pressure after 24 h in comparison with the sham-group (P < 0.05). Cerebral ICAM-1 expression was at its maximum 24 h after induction of sepsis, with the highest expression in the CLP-group. There was no difference in PECAM-1 expression between the groups. Cerebral albumin extravasation increased early after 6 h in both septic groups with a maximum at 24 h after induction of sepsis. These results suggest that there are early changes in the integrity of the blood-brain barrier in the central nervous system in an ongoing septic progress. This provides evidence that these changes are due to inflammatory mediators, and not to the presence of live bacteria. Increased ICAM-1 expression might be an early factor involved in these pathogenic events. Although the role of PECAM-1 cannot conclusively be determined, we were able to show its expression on cerebral endothelium in all groups.