Alterations of Hippocampus and Cognitive Impairment in COPD
Alterations of Hippocampus and Cognitive Impairment in COPD
Demographic characteristics of the control, the mild-to-moderate and the severe COPD groups are depicted in Table 1. The three groups were statistically similar with respect to age, sex, smoking, education level, BMI and cardiovascular disease (P > 0.05).
As shown in Figure 1, hippocampal atrophy was seen in the mild-to-moderate and severe COPD patients when compared with control subjects.
(Enlarge Image)
Figure 1.
MRI images from a control subject, a mild-to-moderate COPD patient and a severe COPD patient. A line has been placed over the region of the hippocampus in one hemisphere. A = control subject; B = mild-to-moderate COPD patient; C = severe COPD patient; AR = the right hippocampus of control subject; AL = the left hippocampus of control subject; BR = the right hippocampus of mild-to-moderate COPD patient; BL = the left hippocampus of mild-to-moderate COPD patient; CR = the right hippocampus of severe COPD patient; CL = the left hippocampus of severe COPD patient.
Table 2 and Figure 2 show that both the right and left hippocampal volumes were significantly smaller in the mild-to-moderate (right P < 0.01, left P < 0.01) and severe COPD (right P < 0.01, left P < 0.01) groups compared to the control group. However, there was no significant difference between the mild-to-moderate COPD group and severe COPD group (P > 0.05).
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Figure 2.
Box plot of the hippocampal volumes in control group and mild-to-moderate and severe COPD groups. The horizontal line through each box represents the median. The ends of each box represent the 25 and 75 percentile locations, and the lines represent the range of the date. The cross of each box represents the mean.* * P < 0.01.
Table 2 also shows that the serum S100B levels increased significantly in the mild-to-moderate (P < 0.01) and severe COPD (P < 0.01) groups compared with the control group. Furthermore, the serum S100B concentration was significantly higher in the severe COPD group than that in the mild-to-moderate COPD group (P < 0.01).
Table 2 shows that the MMSE score was significantly lower in the mild-to-moderate (P < 0.01) and severe COPD (P < 0.01) groups compared with the control group. Moreover, the MMSE score was significantly lower in the severe COPD group than in the mild-to-moderate COPD group (P < 0.01).
Table 3 shows the correlation between the hippocampal volume, pulmonary function parameters, arterial blood gases, MMSE scores and serum S100B levels in COPD patients. The hippocampal volume was positively correlated with the MMSE scores, PaO2 and SaO2 (r = 0.47, P < 0.01; r = 0.55, P < 0.01; r = 0.35, P < 0.05, respectively) (Figure 3A and Figure 3C) in the mild-to-moderate COPD group, while it was positively associated with PaO2 (r = 0.46, P < 0.01) in the severe COPD group (Figure 3D). Furthermore, it was also positively associated with the MMSE scores (r = 0.36, P < 0.01) and negatively correlated with S100B levels (r = −0.33, P < 0.01) in the total COPD patients (Figure 3B).
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Figure 3.
Pearson correlations between the volumes of hippocampus and relevant factors in COPD groups. ● = MMSE scores; ▼ = serum S100B concentrations; ▲ = PaO2; ▲ = SaO2. A = mild-to-moderate COPD group: MMSE (r = 0.47, P < 0.01). B = total COPD patients: MMSE (r = 0.36, P < 0.01); S100B (r = −0.33, P < 0.01). C = mild-to-moderate COPD group: PaO2 (r = 0.55, P < 0.01); SaO2 (r = 0.35, P < 0.05). D = severe COPD group: PaO2 (r = 0.40, P < 0.01).
Table 4 shows the correlation between MMSE scores, pulmonary function parameters, arterial blood gases and the concentrations of serum S100B in COPD patients. The MMSE score was positively associated with PaO2 (r = 0.59, P < 0.01) and negatively correlated with serum S100B concentration ((r = −0.40, P < 0.05) in the mild-to-moderate COPD group, while it was positively associated with PaO2, SaO2 and FEV1 (r = 0.46, P < 0.01; r = 0.37, P < 0.01; r = 0.35, P < 0.05, respectively) and negatively correlated with S100B (r = −0.31, P < 0.05) in the severe COPD group (Figure 4).
(Enlarge Image)
Figure 4.
Pearson correlations between MMSE scores and relevant factors in COPD groups. ▼ = serum S100B concentrations; ▲ = PaO2; ■ = FEV1% predicted. A = mild-to-moderate COPD group: S100B (r = −0.40, P < 0.01); B = severe COPD group: S100B (r = −0.31, P < 0.01); C = mild-to-moderate COPD group: PaO2 (r = 0.59, P < 0.01); D = severe COPD group: PaO2 (r = 0.46, P < 0.01); FEV1 (r = 0.35, P < 0.05).
Results
Demographic Characteristics in the Control Group and COPD Groups
Demographic characteristics of the control, the mild-to-moderate and the severe COPD groups are depicted in Table 1. The three groups were statistically similar with respect to age, sex, smoking, education level, BMI and cardiovascular disease (P > 0.05).
The Alterations of the Hippocampal Volumes and Serum S100B Level in COPD Patients
As shown in Figure 1, hippocampal atrophy was seen in the mild-to-moderate and severe COPD patients when compared with control subjects.
(Enlarge Image)
Figure 1.
MRI images from a control subject, a mild-to-moderate COPD patient and a severe COPD patient. A line has been placed over the region of the hippocampus in one hemisphere. A = control subject; B = mild-to-moderate COPD patient; C = severe COPD patient; AR = the right hippocampus of control subject; AL = the left hippocampus of control subject; BR = the right hippocampus of mild-to-moderate COPD patient; BL = the left hippocampus of mild-to-moderate COPD patient; CR = the right hippocampus of severe COPD patient; CL = the left hippocampus of severe COPD patient.
Table 2 and Figure 2 show that both the right and left hippocampal volumes were significantly smaller in the mild-to-moderate (right P < 0.01, left P < 0.01) and severe COPD (right P < 0.01, left P < 0.01) groups compared to the control group. However, there was no significant difference between the mild-to-moderate COPD group and severe COPD group (P > 0.05).
(Enlarge Image)
Figure 2.
Box plot of the hippocampal volumes in control group and mild-to-moderate and severe COPD groups. The horizontal line through each box represents the median. The ends of each box represent the 25 and 75 percentile locations, and the lines represent the range of the date. The cross of each box represents the mean.* * P < 0.01.
Table 2 also shows that the serum S100B levels increased significantly in the mild-to-moderate (P < 0.01) and severe COPD (P < 0.01) groups compared with the control group. Furthermore, the serum S100B concentration was significantly higher in the severe COPD group than that in the mild-to-moderate COPD group (P < 0.01).
The Cognitive Impairment in COPD Patients
Table 2 shows that the MMSE score was significantly lower in the mild-to-moderate (P < 0.01) and severe COPD (P < 0.01) groups compared with the control group. Moreover, the MMSE score was significantly lower in the severe COPD group than in the mild-to-moderate COPD group (P < 0.01).
Correlations Between Hippocampal Volumes and Relevant Factors
Table 3 shows the correlation between the hippocampal volume, pulmonary function parameters, arterial blood gases, MMSE scores and serum S100B levels in COPD patients. The hippocampal volume was positively correlated with the MMSE scores, PaO2 and SaO2 (r = 0.47, P < 0.01; r = 0.55, P < 0.01; r = 0.35, P < 0.05, respectively) (Figure 3A and Figure 3C) in the mild-to-moderate COPD group, while it was positively associated with PaO2 (r = 0.46, P < 0.01) in the severe COPD group (Figure 3D). Furthermore, it was also positively associated with the MMSE scores (r = 0.36, P < 0.01) and negatively correlated with S100B levels (r = −0.33, P < 0.01) in the total COPD patients (Figure 3B).
(Enlarge Image)
Figure 3.
Pearson correlations between the volumes of hippocampus and relevant factors in COPD groups. ● = MMSE scores; ▼ = serum S100B concentrations; ▲ = PaO2; ▲ = SaO2. A = mild-to-moderate COPD group: MMSE (r = 0.47, P < 0.01). B = total COPD patients: MMSE (r = 0.36, P < 0.01); S100B (r = −0.33, P < 0.01). C = mild-to-moderate COPD group: PaO2 (r = 0.55, P < 0.01); SaO2 (r = 0.35, P < 0.05). D = severe COPD group: PaO2 (r = 0.40, P < 0.01).
Correlations Between Cognitive Function and Relevant Factors
Table 4 shows the correlation between MMSE scores, pulmonary function parameters, arterial blood gases and the concentrations of serum S100B in COPD patients. The MMSE score was positively associated with PaO2 (r = 0.59, P < 0.01) and negatively correlated with serum S100B concentration ((r = −0.40, P < 0.05) in the mild-to-moderate COPD group, while it was positively associated with PaO2, SaO2 and FEV1 (r = 0.46, P < 0.01; r = 0.37, P < 0.01; r = 0.35, P < 0.05, respectively) and negatively correlated with S100B (r = −0.31, P < 0.05) in the severe COPD group (Figure 4).
(Enlarge Image)
Figure 4.
Pearson correlations between MMSE scores and relevant factors in COPD groups. ▼ = serum S100B concentrations; ▲ = PaO2; ■ = FEV1% predicted. A = mild-to-moderate COPD group: S100B (r = −0.40, P < 0.01); B = severe COPD group: S100B (r = −0.31, P < 0.01); C = mild-to-moderate COPD group: PaO2 (r = 0.59, P < 0.01); D = severe COPD group: PaO2 (r = 0.46, P < 0.01); FEV1 (r = 0.35, P < 0.05).
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