Table I. Major Determinants of BBB Integrity.
The main components of the BBB as well as specific protein products from each category with a possible role in age-related BBB changes and clinical conditions are listed.
| BBB Component | Defining Gene Product | Impact of Aging | Clinical Geriatric Relevance |
|---|---|---|---|
| Tight Junctions | Occludin | ? | AIS, AD, DM |
| Zonula Occludins | ? | AIS, PD | |
| Claudin-5 | ? | AIS | |
| Claudin-2 | ? | Sepsis | |
| Gap Junctions | Connexin-43 | ? | Sex differences in AIS outcomes |
| Non-specific tanscytosis | Aquaporin | ? | Hypoxia, AIS Hypoglycemia |
| Efflux Pumps | P-gp | ↓ activity | Adverse drug reactions |
| Delirium, AD, PD | |||
| WMD, Epilepsy | |||
| Brain tumors | |||
| Carrier-mediated transporter | GLUT-1 | ↓ activity | Hypoglycemia, MCI |
| Epilepsy, AIS, AD | |||
| Amino acid transporter | ↓ activity | PD, Epilepsy | |
| Methionine-enkephalin transporter | ↓ activity | Delirium | |
| Choline transporter | ↓ activity | Dementia | |
| Enzymes | Glutathione transferase | ? | PD |
| Basal Lamina | Matrix Metalloproteinase | ? | AIS, PD, AD |
| c-Fn | ? | AIS | |
| Laminin | ? | AIS | |
| Surface Receptors | ICAM-1 | ? | Neuroinflammation |
| CD31 | ? | AIS, WMD | |
| RAGE | ↑ activity | AD | |
| LRP | ↓ activity | AD | |
AIS = acute ischemic stroke, DM = Diabetes mellitus, PD = Parkinson's disease, P-gp = permeability glycoprotein, AD = Alzheimer's disease, WMD = White Matter Disease, GLUT-1 = glucose transporter 1, MCI = Mild Cognitive Impairment, c-Fn = c-fibronectin, ICAM-1 = intercellular adhesion molecule-1, CD31 = platelet endothelial cell adhesion molecule-1, RAGE = receptor for advanced glycation end products, LRP = low-density lipoprotein receptor-related protein