Perivascular lymphatic drainage of β amyloid from the brain

Masafumi Ihara, Akihiko Taguchi

Department of Regenerative Medicine and Research, Institute of Biomedical Research and Innovation

Alzheimer's disease is characterized by accumulation of β amyloid (Aβ) as insoluble deposits in brain parenchyma and in blood vessel walls (cerebral amyloid angiopathy). The distribution of Aβ deposits in the basement membranes of cerebral capillaries and arteries corresponds very closely with the perivascular lymphatic drainage route for interstitial fluid and solutes. Theoretical models indicate that arterial pulsations may be the motive force for the drainage of interstitial fluid containing Aβ. As arteries stiffen with age, the amplitude of pulsations is reduced, perivascular drainage of Aβ becomes less efficient, and insoluble Aβ is deposited in the drainage pathways as cerebral amyloid angiopathy, further impeding the drainage of soluble Aβ. Therapeutic strategies that enhance the patency of this perivascular drainage pathway may help prevent cognitive decline in Alzheimer's disease.

Address correspondence to Dr. Masafumi Ihara, Department of Regenerative Medicine and Research, Institute of Biomedical Research and Innovation (2-2 Minatojima Minamimachi, Chuo-ku, Kobe 650-0047, Japan)