losartan-potassium and Epiretinal-Membrane

To examine vitreous succinate levels from proliferative diabetic retinopathy (PDR) patients and ascertain their association with PDR activity.. Comparative case series.. A total of 81 eyes of 72 PDR patients were divided into active PDR (22 eyes), quiescent PDR (21 eyes), and active PDR with intravitreal bevacizumab injection (38 eyes). Twenty epiretinal membrane (ERM) patients (21 eyes) served as controls.. Mean vitreous succinate levels were 1.27 μM in ERM and 2.20 μM in PDR, with the differences statistically significant (P = .03). When comparing mean vitreous succinate levels (active PDR: 3.32 μM; quiescent PDR: 1.02 μM; active PDR with intravitreal bevacizumab injection: 1.20 μM), significant differences were found between active and quiescent PDR (P < .01) and between active PDR and active PDR with intravitreal bevacizumab injection (P < .01). Even though succinate levels were low, retinopathy activities were very high in patients with active PDR with intravitreal bevacizumab injection. Mean vitreous vascular endothelial growth factor (VEGF) levels (active PDR: 1696 pg/mL; quiescent PDR: 110 pg/mL; active PDR with intravitreal bevacizumab injection: n.d.) were similar to previous reports. Mean vitreous erythropoietin levels (active PDR: 703 mIU/mL; quiescent PDR: 305 mIU/mL; active PDR with intravitreal bevacizumab injection: 1562 mIU/mL) suggested very high retinopathy activities in patients with active PDR with intravitreal bevacizumab injection.. Succinate, like VEGF, may be an angiogenic factor that is induced by ischemia in PDR. Although succinate is reported to promote VEGF expression, VEGF inhibition decreases succinate. Thus, VEGF, via a positive feedback mechanism, may regulate succinate.

Topics: Aged; Angiogenesis Inhibitors; Antibodies, Monoclonal, Humanized; Aqueous Humor; Bevacizumab; Chromatography, High Pressure Liquid; Diabetic Retinopathy; Epiretinal Membrane; Erythropoietin; Female; Humans; Intravitreal Injections; Male; Mass Spectrometry; Middle Aged; Retinal Neovascularization; Succinic Acid; Vascular Endothelial Growth Factor A; Vitreous Body

To investigate the expression of the hypoxia-inducible factor-1alpha (HIF-1alpha) and the protein products of its target genes vascular endothelial growth factor (VEGF), erythropoietin (Epo) and angiopoietins (Angs), and the antiangiogenic pigment epithelium-derived factor (PEDF) in proliferative diabetic retinopathy (PDR) epiretinal membranes.. Sixteen membranes were studied by immunohistochemical techniques.. Vascular endothelial cells expressed HIF-1alpha, Ang-2 and VEGF in 15 (93.75%), 6 (37.5%) and 9 (56.25%) membranes, respectively. There was no immunoreactivity for Epo, Ang-1 and PEDF. There were significant correlations between the number of blood vessels expressing the panendothelial marker CD34 and the numbers of blood vessels expressing HIF-1alpha (r = 0.554; p = 0.026), Ang-2 (r = 0.830; p<0.001) and VEGF (r = 0.743; p = 0.001). The numbers of blood vessels expressing Ang-2 and VEGF in active membranes were higher than that in inactive membranes (p = 0.015 and 0.028, respectively).. HIF-1alpha, Ang-2 and VEGF may play an important role in the pathogenesis of PDR. The findings suggest an adverse angiogenic milieu in PDR epiretinal membranes favouring aberrant neovascularisation and endothelial abnormalities.

Topics: Angiopoietin-2; Antigens, CD34; Cell Division; Diabetic Retinopathy; Epiretinal Membrane; Erythropoietin; Eye Proteins; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Immunoenzyme Techniques; Ki-67 Antigen; Nerve Growth Factors; Serpins; Vascular Endothelial Growth Factor A

It is widely accepted that intravitreous levels of erythropoietin (Epo) are elevated in patients with ischaemic retinal diseases such as proliferative diabetic retinopathy (PDR). The aim of this study was to examine the expression of Epo and the Epo receptor (EpoR) in epiretinal membranes with and without diabetes.. Eighteen epiretinal membranes (PDR (n = 10), idiopathic epiretinal membranes (IERMs) without diabetes (n = 4) and inner limiting membranes (ILMs) (n = 4)) were obtained during pars plana vitrectomy. Formalin-fixed and paraffin-embedded tissues were examined by immunohistochemistry with anti-Epo and EpoR antibodies.. The histopathological findings demonstrated that PDR membranes consisted of a variety of endothelial cells forming a microvascular cavity with red blood cells and non-vascular stromal mononuclear cells. Membranous and cytoplasmic immunoreactivity for EpoR was strongly detected in endothelial cells and stromal cells in all PDR patients. Although microvessels were not observed in IERMs and ILMs, immunoreactivity for EpoR was noted in the cellular component of IERMs, and was weakly detected in ILMs. Epo was not expressed in any membrane.. EpoR was strongly expressed in microvessels of all PDR membranes. The in vivo evidence in this study suggests that Epo in the vitreous binds to EpoR in PDR membranes, which subsequently leads to the proliferation of new retinal vessels. EpoR immunoreactivity in non-vascular stromal cells in PDR membranes, and IERMs and ILMs might be indirectly correlated with ischaemia.

Topics: Aged; Diabetic Retinopathy; Endothelial Cells; Epiretinal Membrane; Erythropoietin; Female; Humans; Immunohistochemistry; Male; Microcirculation; Middle Aged; Receptors, Erythropoietin