Relationship Between Serum GDNF Protein And Cognitive Function Changes In Patients With Dementia

Objective(s):Dementia is a secondary decline in intelligence caused by organic brain lesions,characterized by seriously impairment on memory,other cognitive abilities and human driving,financial management,health care management and independent living.The incidence of dementia is highly correlated with age.The older the patient is,the higher the prevalence of dementia.Alzheimer’s disease(AD),Vascular dementia(VD),and Mixed Dementia(MD)are the most common dementia.Glial cell-derived neurotrophic factor(GDNF)is an important growth factor for the development,survival and maintenance of dopaminergic neurons in the midbrain.GDNF has a strong survival effect on motor neurons and other neuronal subsets in the central and peripheral nervous system.In addition,GDNF is essential for the proliferation,migration and differentiation of neural cells,such as axon growth of hippocampal neurons,synapse formation of hippocampal and cortical neurons,GDNF can be expressed in peripheral blood.Recent studies showed that GDNF might be associated with the onset of Alzheimer’s disease and vascular dementia in cognitive function.Our study hypothesized that the serum concentrations of GDNF protein may vary between healthy individuals and patients with dementia,thus affecting cognitive function and the ability of daily living in patients with dementia;the concentration of GDNF protein may be different in different types of dementia patients.Therefore,we detected the concentrations of GDNF protein in serum of AD,VD and MD patients.We also evaluated the cognitive and daily living ability of dementia patients to explore the relationship between the concentration of GDNF protein and dementia.Methods:Serum GDNF protein concentrations of 32 patients with Alzheimer’s disease,21 patients with vascular dementia,17 patients with mixed dementia and 70 healthy individules were detected by enzyme linked immunosorbent assay(ELISA).The mini-mental state examination(MMSE)and ADAS-cog scale(Alzheimer’s’ s disease assessment scale)were used to access cognitive assessment.The activity of daily living(ADL)scale was used to access impairment of daily function.Statistical package for social science(SPSS)software package was used to analyze the general statistical data(age,gender,educational years,etc.)and all the scale data.P<0.05 showed that the difference was statistically signi:ficant.Results:1.The serum GDNF protein concentration in the study group was significantly different from that in the control group(F=25.98,P<0.05).2.The scores of MMSE,ADL,ADAS-cog scale and serum GDNF protein in AD,VD and MD were significantly different from those in control group(p<0.05),while the scores of serum GDNF protein,MMSE,ADAS-cog and ADL in study group were not significantly different(p>0.05).3.In the study group,serum GDNF protein concentration was correlated with MMSE,ADAS-cog,ADL scale total score(r=0.272、r=-0.356、r=0.248,p<0.05).4.In AD group,serum GDNF protein concentration was correlated with MMSE,ADAS-cog and ADL scores(r = 0.509,r =-0.624,r = 0.384,p<0.05).But in VD and MD group,serum GDNF protein concentration was not correlated with MMSE,ADAS-cog and ADL scores(p>0.05).5.In AD group,serum GDNF protein concentration was positively correlated with memory group and orientation group in MMSE scale(r = 0.426,r = 0.511,,<0.05).The other items were not correlated(p>0.05).6.In AD group,serum GDNF protein concentration was negatively correlated with word memory,structure exercise,delayed word memory,naming,orientation,thinking exercise,and task difficulty in ADAS-cog scale groups(r =-0.573,r =-0.373,r =-0.493,r =-0.494,r =-0.512,r =-0.414,r =-0.378,p<0.05),but not in the remaining groups(p>0.05).Conclusion(s):1.The impairment degree in daily living ability of patients with AD,VD,and MD was associated with the severity of dementia,but not with the type of dementia.2.The serum GDNF protein may be related to the cognitive function of AD,but it may not be related to the cognitive function of VD and MD.3.It was found that the serum GDNF protein concentration was associated with the word memory,structure practice,delayed word memory,naming,orientation,thinking practice,task difficulty and functional impairment in AD patients.The higher concentration of the serum GDNF protein,the lower the degree of cognitive decline and the less the impairment of daily living ability.Serum GDNF protein may be involved in the pathogenesis of AD and may play a protective role in cognitive function changes and impairment of daily living ability.