The brainstem controls mood, sleep and metabolism. The region forms the posterior part of the brain, adjoining and structurally continuous with the spinal cord. As well as affecting emotions, the brainstem provides the primary motor and sensory innervation to the face and neck via the cranial nerves.
According to Dr. Christine Dengler-Crish there are probably several reasons for the development of Alzheimer’s disease, with genetic reasons only representing a minority of cases. This means the search for triggers (or the ‘pathomechanisms’ behind this disease) needs to be wide ranging. As part of the assessment, Dr. Dengler-Crish’s team have been looking at the effects of detrimental bone disease.
The research has found that early reductions in bone mineral density, which are linked with ageing process, are sometimes associated with preclinical Alzheimer’s disease. This is where degeneration in an area of the brainstem occurs, specifically targeting the region that produces the brain’s serotonin. This is the neurochemical which controls mood and sleep. Thus the role played by serotonin in both cognition and behavioral control could be clinically significant.
The inference from the research is that an assessment of bone density should be considered as one of the tests when assessing an individual as being at risk from developing Alzheimer’s disease. A decrease in bone density in itself is not a sign of Alzheimer’s (whereas it is for osteoporosis). However, when it is considered in association with other indications then it can add to the diagnosis process.
Longer-term reductions in bone density and the effect upon serotonin may provide a treatment or prevention area. For example, this could be with the modulation of defined serotonin receptors. In her research note, Dr. Dengler-Crish says: “The findings of this study motivate us to explore the serotonin system as a potential new therapeutic target for this devastating disease.”
The research has been published in the Journal of Alzheimer’s Disease, with the study called “Early Evidence of Low Bone Density and Decreased Serotonergic Synthesis in the Dorsal Raphe of a Tauopathy Model of Alzheimer’s Disease.”
