Collagen fibronectin and

Figure 48-4. Schematic representation of a cell interacting through various integrin receptors with collagen, fibronectin, and laminin present in the ECM. (Specific subunits are not indicated.) (Redrawn after Yamada KM Adhesive recognition sequences. J Biol Chem 1991 266 12809.)...

In the intact blood vessel, ligands involved in adhesion to platelets, such as collagen, fibronectin, and von Willebrand factor, are sequestered in the subendothelium, thus preventing access to platelet adhesive receptors. Table 1 summarizes the functions of platelet membrane integrin receptors. 

Various constituents of fibrosis can be detected with immunohistochemical stains collagen, fibronectin, and laminin.Type IV collagen works best for most brain and meningeal tissues. For routine identification of fibrosis, standard tinctorial stains rival immunohistochemical stains (see Fig. 20.4). 

In order to better understand the pathophysiology associated with these various forms of pulmonary edema, a review of the morphology associated with the capillary-alveolar—intestinal interlace is useful (Fig. 6). From this review it can be seen that fluid in pulmonary capillaries is separated from the alveolar interstitial tissue by the capillary endothelial cells and the capillary basement membrane (commonly called the endothelial barrier). The alveolar surface is separated from the interstitial space by the alveolar-airway barrier, which consists of the alveolar basement membrane, alveolar epithelium, and a layer of pulmonary surfactant within the alveolus. As described previously, the alveolar interstitial tissue is made up of connective tissue (elastin and collagen), fibronectin, and mucopolysaccharides. The interstitial space also contains the pulmonary lympatic system, which functions to drain proteins, large particulate matter, and excess fluid away from the tissue space and to return them to the blood. 

The brain develops and functions within a strictly controlled environment resulting from the coordinated action of different cellular interfaces located between the blood and the extracellular fluids (interstitial fluid and the cerebrospinal fluid (CSF)) of the brain (Strazielle and Ghersi-Egea, 2013). The barrier between the blood and the brain or spinal cord parenchyma proper, referred to as the BBB, is formed by the endothelium of the cerebral micro vessels. Several layers exist between the blood and brain capillary endothelial cells, a basement membrane consisting of type IV collagen, fibronectin and laminin that completely cover the capillaries, pericytes embedded in the basement membrane, and glia/astrocytes that surroxmd the basement membrane (Figure 49.1). Each of these layers could potentially restrict the movement of solutes (Hawkins et al., 2006 Alvarez et al., 2013). 

---