Immunolocalization of 200 kDa neurofilaments in human cardiac endothelial cells

Neurofilaments usually associated with neural tissues are the type IV family of intermediate filaments. Nestin, which is a type VI intermediate filament, is a well known marker of endothelial cells in newly formed blood vessels and is developmentally and structurally related to type IV intermediate filaments. We aimed to determine whether or not cardiac endothelial cells (ECs) label with antibodies for neurofilaments (200 kDa, Novocastra-Leica, clone RT97), as is already known for nestin. We used cardiac samples (sinoatrial nodes/right atrial walls) from cadavers of normal and diabetic donors (6 normal adults, 10 type II diabetic adults, 1 child) for neurofilament immune labeling. Positive labeling of endothelial cells, microvascular and endocardial, was obtained in all samples. As this is the first such evidence, we can only presume that the neurofilament positive labeling of endothelial cells may be due to interactions of nestin and neurofilaments. Further studies are needed to evaluate the hypothesis we reached and, in order to explore whether or not neurofilament antibodies can qualify as markers of angiogenesis.