The locus coeruleus (LC) is a collection of nerve cells–or neurons–in a region of the brainstem called the pons. LC neurons regulate memory and attention by secreting a substance called norepinephrine in cognitive regions of the brain. These neurons degenerate very early in the course of Alzheimer’s disease (AD), even during a stage called mild cognitive impairment (MCI) that precedes frank dementia.
Interestingly, some people display enough AD pathology in their brains that they should have MCI or AD but do not. These people are termed “resilient.” To find out if there are differences in the status of the LC that differentiate resilient people from people with MC/AD, we explored several markers of LC pathology in postmortem tissue from a cohort of subjects who died with a range of disease: from normal to resilient to MCI to AD.
We found that the extent of oxidative stress in LC neurons, as well as hardening of the small blood vessels (arteriolosclerosis) in the pons, was much greater in MCI/AD than in resilient cases. This suggests that poor blood (and oxygen) supply in the pons and the ensuing oxidative damage this causes to LC neurons plays a role in the onset of MCI. Drugs that target this problem may help slow the progression of AD. Read More.