Cognitive impairment and Alzheimer’s disease: Links with oxidative stress and cholesterol metabolism

Figures & data

Table 1 Demographic data and cognitive performance differences between groups in the study

	Control group			AD group
	n	Mean value	SD	n	Mean Value	SD	p
Age	29	70.7	6.9	59	76.4	6.1	≤0.05
Education	29	8.6	3.0	59	7.7	4.5	≥0.05
MMSE	29	25.0	3.1	53	14.1*	6.0	≤0.05
PRAXIAS	29	4.8	0.7	53	3.4*	1.6	≤0.05
FLU ANIMAL	29	14.4	4.2	48	7.4*	3.5	≤0.05
FLU A	28	9.4	3.7	45	5.0*	3.2	≤0.05
BNT	28	10.0	2.6	42	4.7*	4.0	≤0.05
FAB	27	13.8	3.0	43	9.0*	3.4	≤0.05
TAM	29	39.7	5.6	37	16.9*	8.2	≤0.05

Abbreviations: AD, Alzheimer’s disease; BNT, Boston Naming Test; FAB, Frontal Assessment Battery; FLU A, semantic verbal fluency of words with initial A; FLU ANIMAL, Semantic Verbal Fluency of animals with initial A; MMSE, Mini Mental State Examination; PRAXIAS, Ideomotor Praxia by imitation; SD, standard deviation; TAM, Test of Metalinguistic Ability.

Table 2 Comparison of the cholesterol parameters (mg/dL) of AD subjects and neurologically normal controls

	Control (n = 29)		AD (n = 55)
	Mean Value	SD	Mean Value	SD	p value
Total-cholesterol	200	42	202	39	> 0.05
Tryglicerides	147	58	132	55	> 0.05
HDL-cholesterol	54	13	52	11	> 0.05
LDL-cholesterol	122	34	127	34	> 0.05
VLDL-cholesterol	23	7	23	8.0	> 0.05
cholest/HDL index	3.8	0.7	4.0	0.9	> 0.05

Abbreviations: AD, Alzheimer’s disease; HDL, high-density lipoprotein; LDL, low-density lipoprotein; SD, standard deviation

Figure 1 Ferric reducing ability of plasma (eq. Fe(II) μM) of patients with Alzheimer’s disease at different stages of the disease, as evaluated by GDS. Other details in Methods. The number of subjects in every group (n) was: n = 23 in the mild AD (GDS = 3–4);n = 24 in the moderate AD (GDS 5), and n = 12 for severe AD; n = 29 for the control group.

Note: * Significant differences (p < 0.05) between control subgroup (or mild AD) vs moderate or severe AD. One-way ANOVA and Bonferroni’s comparison test wre used to assess differences in mean values.

Table 3 FRAP, MDA levels, and TAC-crocin mean values and SD in both AD and control groups

	Control			AD
	n	Mean value	SD	n	Mean value	SD	P value
FRAP (μM eq. Fe^2+)	29	1,215	317	59	1,118	253	> 0.05
MDA levels (μmol/L)	29	0.67	0.48	59	0.57	0.34	> 0.05
TAC-crocin (μmol/L Trolox/mL plasma)	14	13.1	6.6	31	11.2	4.8	> 0.05

Abbreviations: AD, Alzheimer’s disease; FRAP, ferric-reducing ability of plasma; MDA, malondialdehyde; SD, standard deviation; TAC, total antioxidative capacity.

Figure 2 (A) Correlation between FRAP (eq Fe(II) μM) and cognitive impairment in AD patients (r = 0.443, P < 0.01). (B) Correlation between FRAP (eq Fe(II) μM) and PRAXIAS test (r = 0.301, P < 0.05).

Figure 3 (A) Correlation between total cholesterol (mg/dL) and GDS in AD patients (r = −0.298, P < 0.05). (B) Correlation between VLDL (mg/dL) and GDS in AD patients (r = −0.382, P < 0.01).

Figure 4 Correlations between Cholesterol/HDL index and Boston Naming Test (BNT) values in AD patients (r = 0.464, P < 0.01). Other experimental details in Methods section.