New model of proliferative vitreoretinopathy in rabbit for drug delivery and pharmacodynamic studies

Blinding retinal diseases become more epidemic as the population ages. These diseases, such as diabetic retinopathy and macular edema, are of chronic nature and require protracted drug presence at the disease site. A sustained intravitreal porous silicon delivery system with dexamethasone (pSiO2-COO-DEX) was evaluated in a new rabbit model of proliferative vitreoretinopathy (PVR) in a real treatment design. In contrast to the pretreatment design model, pSiO2-COO-DEX was intravitreally injected into the eyes with active inflammation. Subretinal injection of vascular endothelial growth factor (VEGF) and Matrigel induced a late-onset vitreoretinal inflammation that gradually developed into PVR. This method mimics the human disease better than PVR induced by either intravitreal cell injection or trauma. The pSiO2-COO-DEX intervened eyes had minimal PVR, while balanced saline solution or free dexamethasone intervened eyes had significantly more PVR formation. In addition, adding VEGF to the Matrigel for subretinal injection induced greater inflammation and retinal neovascularization in comparison to only Matrigel injected under the medullary ray. Clinical and pathological examinations, including fundus fluorescein angiography and optical coherence tomography, confirmed these changes. In the current study, neither subretinal injection of Matrigel or subretinal injection of VEGF and Matrigel induced choroidal neovascularization. However, the current PVR model demonstrates a chronic course with moderate severity, which may be useful for drug screening studies

Vascular Remodeling in Health and Disease

The term vascular remodeling is commonly used to define the structural changes in blood vessel geometry that occur in response to long-term physiologic alterations in blood flow or in response to vessel wall injury brought about by trauma or underlying cardiovascular diseases.1, 2, 3, 4 The process of remodeling, which begins as an adaptive response to long-term hemodynamic alterations such as elevated shear stress or increased intravascular pressure, may eventually become maladaptive, leading to impaired vascular function. The vascular endothelium, owing to its location lining the lumen of blood vessels, plays a pivotal role in regulation of all aspects of vascular function and homeostasis.5 Thus, not surprisingly, endothelial dysfunction has been recognized as the harbinger of all major cardiovascular diseases such as hypertension, atherosclerosis, and diabetes.6, 7, 8 The endothelium elaborates a variety of substances that influence vascular tone and protect the vessel wall against inflammatory cell adhesion, thrombus formation, and vascular cell proliferation.8, 9, 10 Among the primary biologic mediators emanating from the endothelium is nitric oxide (NO) and the arachidonic acid metabolite prostacyclin [prostaglandin I2 (PGI2)], which exert powerful vasodilatory, antiadhesive, and antiproliferative effects in the vessel wall

'Outside-the-box' therapeutic solutions for ischaemia-reperfusion myocardial protection

International audienceNo abstract availabl

Other Things Behind the Low Rate of Heart Failure Trial Publication

International audienceNo abstract availabl

Biomarkers for Myocardial Infarction Type Discrimination-The Key Might Be in the Time Course of the Disease

International audienceNo abstract availabl

Acute Pulmonary Embolism and Thrombus Entrapped in the Patent Foramen Ovale in a Patient with COVID-19

International audienceA 61-year-old patient presented for syncope and a 1-week history of fever. He was diagnosed with a COVID-19 infection without pulmonary injury associated with an intermediate-risk bilateral pulmonary embolism. Computed tomographic scan and transesophageal echography were performed confirming a mobile in-transit embolus, originating from the right cavities and extending to the right ventricle through the patent foramen ovale. The patient underwent a surgical embolectomy without complications. COVID-19 was found to be the only current risk factor in our patient. This could warrant consideration of extending thromboprophylaxis indication to COVID-19 patients with certain criteria even without hospitalization indication or pulmonary injury

Reply to "Is pheochromocytoma-induced takotsubo syndrome different from typical takotsubo syndrome?"

International audienceNo abstract availabl

Acute necrotizing eosinophilic myocarditis presented as an acute coronary syndrome

International audienceNo abstract availabl