Memantine plus vitamin D prevents axonal degeneration caused by lysed blood.

Intracranial hemorrhage, whether due to traumatic brain injury or ruptured cerebral aneurysm, is characterized by major neurological damage and a high mortality rate. Apart from cerebral vasospasm and mass effect, brain injury results from the release of unclotted blood that contacts neurons causing calcic stress. The combination of memantine with vitamin D, a neurosteroid hormone, may prevent blood neurotoxicity. Our purpose was to examine the potential protective effects of memantine + vitamin D against lysed or clotted blood in cortical neuronal cultures. We provide the first evidence that cortical axons in contact with lysed blood degenerate less after exposure to lysed blood in microfluidic neuronal cultures enriched with both memantine and vitamin D compared to control medium and cultures enriched with only memantine or only vitamin D. The reported synergistic neuroprotective effect of memantine + vitamin D, the combination originating an effect stronger than the sum, strongly encourages using both drugs following intracranial hemorrhage.