Effect of Osteopathic Cranial Manipulative Medicine on an Aged Rat Model of Alzheimer Disease.

Context: In the aging brain, reduction in the pulsation of cerebral vasculature and fluid circulation causes impairment in the fluid exchange between different compartments and lays a foundation for the neuroinflammation that results in Alzheimer disease (AD). The knowledge that lymphatic vessels in the central nervous system play a role in the clearance of brain-derived metabolic waste products opens an unprecedented capability to increase the clearance of macromolecules such as amyloid beta proteins. However, currently there is no pharmacologic mechanism available to increase fluid circulation in the aging brain. Objective: To demonstrate the influence of an osteopathic cranial manipulative medicine (OCMIM) technique, specifically, compression of the fourth ventricle, on spatial memory and changes in substrates associated with mechanisms of metabolic waste clearance in the central nervous system using the naturally aged rat model of AD. Results: Significant improvement was found in spatial memory in 6 rats after 7 days of OCMM sessions. Live animal positron emission tomographic imaging and immunoassays revealed that OCMM reduced amyloid beta levels, activated astrocytes, and improved neurotransmission in the aged rat brains. Conclusion: These findings demonstrate the molecular mechanism of OCMM in aged rats. This study and further investigations will help physicians promote OCMM as an evidence-based adjunctive treatment for patients with AD.