String vessels (capillary remnants) in the brain and eye in development, senescence, neurodegeneration, and after irradiation

• Published in: The FASEB journal 2007-04, Vol.21 (5), p.A396-A396
• Main Authors: Brown, William R., Thore, Clara R., Moody, Dixon M., Mott, Ryan T., Anstrom, John A.
• Format: Article
• Language: English
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.21.5.A396-a

Starting with Henle, in 1838, there has been a sporadic literature describing vascular structures variously named string vessels, intercapillary bridges, intervascular connective tissue strands, or capillary strands. We bring together diverse studies from our laboratory and others to present a comprehensive view of the nature of string vessels. They are essentially composed of basement membrane components such as collagen IV, although they may occasionally have pericytes or cellular elements such as nuclei. In studies of human brains from preterm babies through senescence, we found string vessels to be common at all ages from preterm to aged, but they did not appear to persist and accumulate over extended periods of time. They were increased in Alzheimer's disease. In leukoaraiosis (age‐related white matter degeneration) capillaries were greatly reduced, but at the time of death string vessels were few. After irradiation of rat brains, we found string vessels to be increased. We also present related findings published by others on studies of the normal and pathologic brain and after irradiation of human and rat eyes. From all these studies, we conclude that string vessels are remnants of disappearing capillaries, in both normal and pathological conditions in brains and eyes. Supported by the March of Dimes Research Foundation, and NIH grants NS 20618, NS 36780, and CA 113321.