SALIVARY NGF MAY BECOME A MERKMAL FOR EARLY DIAGNOSIS OF SENILE DEMENTIA

Nerve growth factor (NGF), a neurotrophic factor, regulates growth, maintenance, proliferation, and survival of neurons. NGF is abundantly contained in the saliva, but its functional role remains to be explored. The present study investigated the relations between the salivary NGF levels and age/cognitive functions/hippocampal atrophy in 113 human subjects (male:female=46:67) at ages ranging from 13 to 91 years old (average, 74 years old).The salivary NGF levels decreased with age. Subjects with the higher salivary NGF levels got the better Mini-Mental State Examination (MMSE) score; the salivary NGF level in subjects with the MMSE score more than 20, corresponding to normal, was 91.0 ± 14.7 pg/mL and that in subjects with the MMSE score below 20, corresponding to dementia, was 35.3 ± 7.5 pg/mL. This indicates that those with the salivary NGF levels below 35 pg/mL may have a high risk of dementia.The hippocampal size, that is calculated frombrain coronal magnetic resonance imaging (MRI),reduced in association with decrease of the salivary NGF levels. The salivary NGF levels, thus, could become a merkmal for early diagnosis of senile dementia