KRIT1: A Traffic Warden at the Busy Crossroads Between Redox Signaling and the Pathogenesis of Cerebral Cavernous Malformation Disease.

Significance: KRIT1 (Krev interaction trapped 1) is a scaffolding protein that plays a critical role in vascular morphogenesis and homeostasis. Its loss-of-function has been unequivocally associated with the pathogenesis of Cerebral Cavernous Malformation (CCM), a major cerebrovascular disease of genetic origin characterized by defective endothelial cell-cell adhesion and ensuing structural alterations and hyperpermeability in brain capillaries. KRIT1 contributes to the maintenance of endothelial barrier function by stabilizing the integrity of adherens junctions and inhibiting the formation of actin stress fibers. Recent Advances: Among the multiple regulatory mechanisms proposed so far, significant evidence accumulated over the past decade has clearly shown that the role of KRIT1 in the stability of endothelial barriers, including the blood-brain barrier, is largely based on its involvement in the complex machinery governing cellular redox homeostasis and responses to oxidative stress and inflammation. KRIT1 loss-of-function has, indeed, been demonstrated to cause an impairment of major redox-sensitive mechanisms involved in spatiotemporal regulation of cell adhesion and signaling, which ultimately leads to decreased cell-cell junction stability and enhanced sensitivity to oxidative stress and inflammation. Critical Issues: This review explores the redox mechanisms that influence endothelial cell adhesion and barrier function, focusing on the role of KRIT1 in such mechanisms. We propose that this supports a novel model wherein redox signaling forms the common link between the various pathogenetic mechanisms and therapeutic approaches hitherto associated with CCM disease. Future Directions: A comprehensive characterization of the role of KRIT1 in redox control of endothelial barrier physiology and defense against oxy-inflammatory insults will provide valuable insights into the development of precision medicine strategies. Antioxid. Redox Signal. 38, 496-528.

Fractal analysis of fluoroangiographic patterns in anterior ischaemic optic neuropathy and optic neuritis: a pilot study.

BACKGROUND: To evaluate by means of fractal analysis the vascular pattern of the optic nerve head obtained by fluorescein angiogram, in non-arteritic anterior ischaemic optic neuropathy (NAION) and optic neuritis (ON). METHODS: Twenty-nine patients at the Department of Ophthalmology of the University of Siena, diagnosed as having either NAION or ON by clinical and instrumental criteria, were prospectively subjected to fractal analysis: 11 patients with NAION and 18 patients with ON. In the ON group, 12 patients showed optic disc oedema, whereas six patients showed no optic disc oedema. The unaffected eyes of six patients with NAION and of seven patients with ON associated with optic disc oedema served as controls. RESULTS: The mean fractal dimension D was 1.84 +/- 0.09 in the NAION group, 1.92 +/- 0.04 in the ON group with optic disc oedema, 1.86 +/- 0.04 in the ON group without optic disc oedema and 1.63 +/- 0.06 in the control group; all case groups showed significantly higher values than controls (P < 0.01). Among the case groups, the ON group with optic disc oedema showed a significantly higher mean fractal dimension value than the others (P < 0.01). CONCLUSIONS: Our data suggest that eyes with ON and NAION seem to have increased vascular complexity in the optic nerve head, manifested as an increase in fractal dimension.