The Role of Blood Brain Barrier Repair in Neurological Health
The blood brain barrier is one of the most important anatomical features of the central nervous system. This barrier serves as a selective gatekeeper between the blood and the brain, controlling the exchange of cells, molecules, ions, and other substances. It allows the entry of essential nutrients and signaling molecules required for proper neuronal functioning while blocking the passage of toxins, pathogens, inflammation-causing agents, and other potentially damaging compounds.
A Frontier for Combating Neurological Disease
Innovations in blood brain barrier repair constitute a pivotal frontier in neuroscience. Detecting areas of hyperpermeability and targeted therapeutic sealing of damaged vessels promises new hope for those suffering from neurological illness. By re-establishing this vital protective interface, the progression of many severe, refractory, and devastating conditions could potentially be halted or reversed.
Disruption Compromises Neurological Health
A wide range of neurological and neurodegenerative conditions correlate with and are exacerbated by a breakdown in blood brain barrier integrity. These include stroke, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, epilepsy, traumatic brain injury, and normal aging.
In ischemia during stroke causes disruption of the nutrient and oxygen supply, alterations in cerebrovascular endothelial cells, and serious compromise of the blood-brain barrier. This allows an uncontrolled influx of calcium, sodium, and inflammatory cells into vulnerable ischemic areas, propagating cell death and neurological injury.
Alzheimer’s disease involves heightened neuroinflammation from microglia activation, which can spur localized blood brain barrier disruption. Leakage of plasma proteins over the barrier then further elicits inflammatory changes in neurons and glia. Deposition of the endogenous beta-amyloid peptide is also closely associated with sites of barrier disruption.
In multiple sclerosis, the breakdown of the blood-brain barrier enables large-scale invasion of immune cells and autoantibodies across the endothelium into the white matter. This drives focal inflammation, demyelination, and neurological dysfunction.
Overall the effects can be severe. Unregulated transport over a damaged barrier leaves neurons vulnerable to ions, toxins, enzymes, and cytotoxic compounds that rapidly degrade cell and tissue function. Restoring normal barrier function is, therefore, an immense opportunity for stabilizing neurological health.
Promising Advances in Barrier Repair
Given the pivotal role of blood brain barrier disruption in neurological disease, substantial research effort is focused on developing technologies and therapies to detect and repair sites of damage. Approaches generally aim to seal leaks and gaps in the endothelium to restore controlled transport.
One extremely dynamic method utilizes focused ultrasound in combination with systemically circulating microbubbles to temporarily open the blood brain barrier in a targeted location. This allows the delivery of therapeutic compounds precisely to areas of injury while avoiding widespread barrier disruption. The microbubbles can then be manipulated with sound waves to gently reseal the momentary openings.
Stem cell transplantation seeks to regenerate damaged endothelium through the integration and differentiation of cells like neural stem cells, mesenchymal stem cells, or CD34+ cells into cerebrovascular cells. Gene-modified variants can enhance this endothelial reconstituting ability.
Specialized drugs are also showing promise, with some molecules directly sealing leaky endothelial walls while others stimulate inherent vascular repair mechanisms. For example, cyclic peptide-based “sealants” bind tightly to endothelial cells to stabilize vascular integrity. Other medications target remodeling pathways to stimulate proliferation and tight-junction expression in native brain endothelial cells.
Additionally, techniques, like MRI-guided focused electrical stimulation cerebrovascular cells, are being investigated for the ability to trigger self-sealing of endothelial gaps and lesions induced by injury and disease. Overall, convergence and refinement of these approaches could yield breakthrough treatment options for common neurodegenerative disorders.
