Summary
The response of conjunctival vascular dilatations to topical epinephrine was tested in 25 subjects. Irregular venular dilatations disappeared, venular microaneurysms underwent partial contraction, while capillary microaneurysms did not contract following application of epinephrine. Biopsy specimens of the conjunctiva were examined by light and electron microscopy in four diabetic patients in whom microaneurysms had been demonstrated by biomicroscopy. Marked thickening of the basement membrane and enlargement of the endothelial cytoplasm were noted in the dilated capillaries. Pericytes were normal in number and appearance. Conjunctival capillary dilatations in three nondiabetics failed to show these changes. A milder degree of basement membrane thickening was observed in a younger diabetic. The finding of conjunctival capillary microaneurysms in a diabetic would thus appear to indicate the presence of microangiopathy.
Résumé
La réponse des dilatations vasculaires conjonctivales à l'application locale d'adrénaline a été testée chez 25 sujets. Les dilatations veinulaires irrégulières disparaissaient, les microanévrysmes veinulaires subissaient une contraction partielle, tandis que les microanévrysmes capillaires ne se contractaient pas après application d'adrénaline. Des spécimens de biopsie de la conjonctive ont été examinés au microscope à lumière et au microscope électronique chez quatre sujets diabétiques, chez lesquels les microanévrysmes avaient été mis en évidence par biomicroscopie. On a noté un épaississement marqué de la membrane basale et un agrandissement du cytoplasme endothélial dans les capillaires dilatés. Les péricytes étaient normaux en nombre et en apparence. Chez trois non-diabétiques les dilatations capillaires conjonctivales n'ont pas subi ces modifications. On a observé un degré plus faible d'épaississement de la membrane basale chez un diabétique plus jeune. La découverte de microanévrysmes capillaires conjonctivaux chez un diabétique semblerait donc indiquer la présence de microangiopathie.
Zusammenfassung
Das Ansprechen von Bindehautgefäß-Aneurysmen auf lokale Adrenalinapplikation wurde bei 25 Vp. überprüft. Darunter verschwanden unregelmäßige venöse Erweiterungen und die venösen Mikroaneurysmen kontrahierten sich teilweise, während sich die kapillären Mikroaneurysmen unter Adrenalin nicht verkleinerten. Biopsiepräparate aus der Bindehaut von 4 Diabetikern, bei denen sich durch Biomikroskopie Mikroaneurysmen hatten nachweisen lassen, wurden licht- und elektronenmikroskopisch untersucht. In den erweiterten Kapillaren fielen dabei eine deutliche Verdickung der Basalmembran und eine Vermehrung des endothelialen Cytoplasma auf. Die Pericyten erschienen nach Zahl und Aussehen normal. Erweiterungen von Bindehautkapillaren bei 3 Nichtdiabetikern zeigten diese Veränderungen nicht. Bei einem jüngeren Diabetiker ließ sich eine weniger ausgeprägte Verdickung der Basalmembran beobachten. Der Nachweis von Mikroaneurysmen in den Bindehautkapillaren eines Diabetikers spricht also für das Vorliegen einer Mikroangiopathie.
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This investigation was conducted under a Fight for Sight Postdoctoral Research Fellowship of the National Council to Combat Blindness, Inc., New York, New York (Dr. Chazan), and supported by grants from the U.S. Public Health Service (NB 02698 and AM — 04146), the Massachusetts Lions' Eye Research Fund, and the John A. Hartford Foundation, Inc.
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Chazan, B.I., Kuwabara, T., Balodimos, M.C. et al. The reactivity and ultrastructure of conjunctival microaneurysms in diabetes. Diabetologia 5, 331–338 (1969). https://doi.org/10.1007/BF00452908
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DOI: https://doi.org/10.1007/BF00452908