Enhanced Butyrylcholinesterase Activity may be the Common Link in Triggering Low-Grade Systemic Inflammation and Decrease in Cognitive Function in Diabetes Mellitus and Alzheimer's disease

There is increasing evidence that diabetes mellitus and Alzheimer's disease occur more often than by chance. Recently, we proposed that increase in the activity of the enzyme butyrylcholinesterase could be a common link between these two conditions. Acetylcholine is an anti-inflammatory molecule. Butyrylcholinesterase by inactivating acetylcholine may enhance inflammation and induce decline in cognitive function. In the present study, it was noted that streptozotocininduced diabetic animals showed dyslipidemia, increase in plasma lipid peroxides, decrease in circulating plasma superoxide dismutase activity, decline in cognitive function as assessed by the Morris water maze method, and a significant increase in serum butyrylcholinesterase activity. These results suggest that increased plasma and, possibly, tissue concentrations of butyrylcholinesterase lead to decrease in acetylcholine levels, an anti-inflammatory molecule, which may trigger low-grade systemic inflammation in diabetes mellitus and Alzheimer's disease that could account for decline in cognitive function.