Cranial Manipulation Modulates Cholinergic Pathway Gene Expression in an Animal Model of Age-related Cognitive Decline

Age dependent dementia is a devastating disorder afflicting the growing older population around the world. Although pharmacological agents improve symptoms of dementia, age related co-morbidities combined with adverse effects often outweigh their clinical benefits. Therefore, non-pharmacological therapies are being investigated as an alternative. Randomized controlled trials and observational studies have shown promising results for cranial manipulation as a treatment for dementia and other nervous system disorders. In this study we examine the effect of osteopathic cranial manipulative medicine (OCMM) on gene expression, in an animal model for age-related cognitive decline (aged rats). We found that OCMM significantly affected the expression of 36 genes in the neuronal pathway (False Discovery Rate (FDR) < 0.004). The top five neuronal genes with the largest fold-change (Slc5a7, Chat, Slc18a3, Adcy5 and Cacna2d2, >2-fold change, FDR<0.004) are part of the cholinergic neurotransmission mechanism, which is known to affect cognitive function. Slc5a7, the highest overexpressed neuronal gene (3-fold change) encodes a sodium and chloride ion-dependent high-affinity transporter that mediates choline uptake for acetylcholine synthesis in cholinergic neurons. This is the pathway enhanced by the clinically used Alzheimer’s disease drug Donepezil, which selectively inhibits acetylcholinesterase, an enzyme that catalyzes endogenous acetylcholine degradation. In addition, 40% of significant differentially expressed (SDE) genes (FDR<0.004), have been previously implicated in neurological disorders. Overall, SDE genes and their role in central nervous system signaling pathways suggest a connection to previously reported OCMM induced behavioral and biochemical changes in rat models of age-dependent dementia. Further investigation in this direction will provide a better understanding of the molecular mechanisms of OCMM and its potential in clinical applications. With clinical validation, OCMM could represent a much needed low-risk adjunct treatment for age-related dementia including Alzheimer’s disease.