ABSTRACT
Shell-less culture of chick chorioallantoic membrane (CAM) of developing chicken embryos is a useful model to evaluate the effects of vascular agents. We assessed the response of CAM vessels to epoxyeicosatrienoic acids (EETs), derivatives of the essential fatty acid arachidonic acid, that have a number of important biological functions, including dilation of microvessels in the coronary, cerebral, renal, and mesenteric circulations. Three of four regioisomers of EETs, 14,15-, 11,12-, and 8,9-EET, induced a characteristic dose-dependent acute hyperemia within 4 min after application on 10-day-old CAMs. This response was marked in early stages of development (between days 8 and 10), but the frequency and intensity of the response were reduced after 11 days of development. Histological examination demonstrated that the hyperemia was not due to extravasation of erythrocytes. However, many capillaries were distended and contained densely packed erythrocytes as compared to uniformly arranged vessels and erythrocytes in untreated CAMs. Transmission electron microscopy showed the basal laminae surrounding capillaries remained intact, similar to those in vehicle-treated or untreated CAM tissue. The hyperemia was specific to EETs since we did not observe it to be induced by other vasodilators such as nitric oxide or prostacyclin. In conclusion, we report a novel vascular response to EETs using the CAM as an in vivo model. These lipids specifically distend a subset of capillaries in a dose- and development-dependent manner.
Subject(s)
8,11,14-Eicosatrienoic Acid/analogs & derivatives , Chorioallantoic Membrane/blood supply , Hyperemia/embryology , Vasodilator Agents , Animals , Capillaries/drug effects , Capillaries/embryology , Capillaries/pathology , Chick Embryo , Culture Techniques , Disease Models, Animal , Dose-Response Relationship, Drug , Hyperemia/chemically induced , Hyperemia/pathology , Neovascularization, Physiologic/drug effects , Nitric Oxide Donors/pharmacology , Time Factors , Vasodilator Agents/pharmacology , Vitelline Membrane/blood supplyABSTRACT
Muestras de regiones de infartación placentaria se tomaron de una paciente con preeclampsia y se procesaron con las técnicas convencionales de la Microscopía Electrónica de Barrido. Los resultados revelan aglomeración de vellosidades con disminución del espacio intervelloso, dilatación de capilares e hipertrofía de la vellosidad. Se notaron en las observaciones necrosis del trofoblasto y deposición de fibrina en la periferia de las vellosidades simultáneamente con fibrosis del estroma y necrosis de los vasos a medida que envejece el infarto. En algunos casos el borde periférico vellositario se rodea de fibrinoide, con células trofoblásticas proliferativas en él incluidas que posteriormente sufren necrosis. Los infartos más viejos contienen depósitos de fibrinoide que envuelven a vellosidades fantasmales que contienen gran cantidad de fibras colágenas. Estos resultados indican cambios isquémicos agudos y crónicos, mostrando una visión de conjunto tridimensional que expresan mejor las lesiones con una mayor profundidad de campo y superficie de análisis. Este nuevo aspecto morfológico detalla y extiende previas investigaciones revelando cambios degenerativos desde la fase hemorrágica hasta la colagenosis del estroma velloso
