Objective: Features of the lipid profile specially cholesterol levels are association with PD risk. However no such data exists on the association of these plasma markers with structural brain changes in PD. The primary site of PD pathology is the nigrostriatal tract which then progresses to the cingulium. The nigrostriatal tract is extensively damaged prior to PD onset. Here we applied the connectometry framework to analyses structural connectivity in a total of 39 drug-naïve PD patients and 23 controls using a multiple regression model.

Background: The brain HDL-like particles have a variety of surface lipoproteins including apoE and apoA-I. The apoA-I found in these particles is probably derived from blood HDL via a SR-B1 mediated uptake. Lower plasma levels of apoA-I is associated with earlier onset of PD and greater putaminal DAT deficit and a more rapid motor decline in PD. However apoA-I levels have never been investigated regarding changes in structural brain connectivity.

Methods: Data used in the preparation of this paper was obtained from Parkinson’s Progression Markers Initiative (PPMI) database (www.ppmi-info.org/data/)

Table 1. Comparison of clinical and demographic information between NCs and patients with PD

Clinical / Demographical Features	NC (23)	PD (39)	P value
Baseline Age at Plasma Mean	63(9)	63.8(8)	0.85
Female/Male no.	9/14	14/25	0.09
Age at Diagnosis Mean	–	63.8 (9)	–
UPDRS Part III Motor Score Mean (SD)	–	18.9(9)	–
H & Y stage Mean (SD)	–	1.6 (0.5)	–

. The diffusion data were reconstructed in the MNI space using q-space diffeomorphic reconstruction to obtain the spin distribution function. A diffusion sampling length ratio of 1.25 was used, and the output resolution was 2 mm. Diffusion MRI connectometry was conducted using a multiple regression model considering Cholesterol, Non.HDL, apoA-I, EGF, LDL, HDL, Age, and Sex.

Results: The analysis showed a significant negative correlation (FDR= 0.04) between Apo_AI of PD

Table 2. Outcome Measure by connectometry in PD

	PERCENTAGE THRESHOLD	PERMUTATIONS	FDR
APO_AI	200%	2000	0.0408163*
CHOLESTEROL	200%	2000	0.276948
NON-HDL	200%	2000	0.169543
HDL	200%	2000	0.338126
LDL	168.47%	2000	0.4
EGF	200%	2000	>0.5
AGE	42.58%	2000	0.111979
SEX	28.86%	2000	0.195567

and another factors have no association with structural brain network and connectivity in two fiber pathways: 1) Cingulium, 2) Corticospinal Tracts. Also there is no association between Plasma factors, age and sex in normal cases. shows the significant pathway which are associated with Apo_A.

Conclusions: Altered lipid levels in the plasma may affect presynaptic and mitochondrial membrane composition and lead to accumulation of Lewy bodies in the brain. Lower cholesterol or apoA-I level is associated with PD risk. The limbic system is not usually affected in early stage PD, when nigrostriatal damage is more prominent. We found that lower plasma apoA-I levels in newly-diagnosed PD patients is associated with structural changes in cingulium as part of the limbic system.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/the-association-between-structural-brain-connectivity-with-plasma-apo-a1-levels-in-parkinsons-disease-connectometry-approach/