Figure 1.

The glia-neuro-vascular interface (also denoted the glia-neuro-vascular unit/coupling) incorporates the capillary wherein its circumference consists of endothelial cells (ECs) having tight junctions and pericytes (P) with processes (Pp). The relationship between the endothelial cells and pericytes in humans is 1:1–3:1, decreasing with age and in diseases. The basement membrane (BM) is a loose matrix between endothelial cells (ECs) and pericytes (Ps) and the astrocytic end-feet (EF). The astrocytic end-feet processes create a donut shaped structure enclosing the basement membrane (BM). There are inter-end-feet-gaps between the endfoot (EF) processes enabling passage of molecules to the interstitial tissue. Normal end-feet (EF) are indicated in blue to the left while pathological end-feet (EF) in red color to the right. Other components are the astrocytes (A), neurons (N) and microglia (M). In IIH, there is patchy astrogliosis, causing changes to the normal configuration of astrocytes. Moreover, there is loss of integrity of the BBB with degeneration of basement membrane and pericyte processes, and BBB leakage of the blood proteins fibrinogen and fibrin. Extra-vascular fibrin(ogen) is not demonstrable in normal adult brains and is prominently pro-inflammatory. Our present disclosure of blood-brain-dysfunction in IIH subjects indicates that the glia-neuro-vascular unit is likely associated with the pathogenesis of the disease. Illustration: Ine Eriksen, University of Oslo.