The unique alterations of hippocampus and cognitive impairment in chronic obstructive pulmonary disease

Abstract

BackgroundCognitive impairment has been found in chronic obstructive pulmonary disease (COPD) patients. However, the structural alteration of the brain and underlying mechanisms are poorly understood.MethodsThirty-seven mild-to-moderate COPD patients, forty-eight severe COPD patients, and thirty-one control subjects were recruited for cognitive test and neuroimaging studies. Serum levels of S100B,pulmonary function and arterial blood gas levels were also evaluated in each subject.ResultsThe hippocampal volume was significantly smaller in COPD patients compared to the control group. It is positively correlated with a mini mental state examination (MMSE) score, SaO2 in mild-to-moderate COPD patients, the levels of PaO2 in both mild-to-moderate and severe COPD patients. Higher S100B concentrations were observed in mild-to-moderate COPD patients, while the highest S100B level was found in severe COPD patients when compared to the control subjects. S100B levels are negatively associated with MMSE in both mild-to-moderate and severe COPD patients and also negatively associated with the hippocampal volume in the total COPD patients.ConclusionsHippocampal atrophy based on quantitative assessment by magnetic resonance imaging does occur in COPD patients, which may be associated with cognitive dysfunction and the most prevalent mechanism accountable for hippocampal atrophy is chronic hypoxemia in COPD. Higher serum S100B levels may be peripheral biochemical marker for cognitive impairment in COPD.

Cognitive Assessment in Patient of Chronic Obstructive Pulmonary Disease

“…In the present study mean FEV1 was 1.42 with standard deviation of 0.49 in case group. In the study conducted by Gupta et al, 35 the mean FEV1 of the cases in the COPD group was 1.48 (SD 0.50) which is comparable with our finding. In the study conducted by Jing Li and Guang-He Fei, the mean FEV1 (% of predicted FEV) was 106.1, 61.14 and 34.15 liters in control group, mild to moderate COPD group and severe COPD group respectively.…”

“…In the study conducted by Neeta Thakur et al, the mean age of the cases in the COPD group is 58.2 (SD 6.2) years and in the control group is 58.5 (SD 6.2) years. In the study conducted by Gupta et al, 35 the mean age of the cases in the COPD group was 57.25 (SD 9.07) years and in the control group is 56.9 (SD 9.21) years (p >0.05). In the study conducted by Jing Li and Guang-He Fei, 34 the mean age was 66.48, 69.27 and 67.60 years in control group, mild to moderate COPD group and severe COPD group respectively.…”

“…In the study conducted by Gupta et al, 35 none of the control was smoker while in case group average cigarette smoking per day was 39.95 (SD 20.94). In the study conducted by Manju Bhaskar, 36 80% cases had smoking abuse in case group and 30% cases in the control group had smoking abuse.…”

Structural Brain Changes in Patients With COPD

“…In a second step, a small-volume analysis with a family-wise error correction (FWEsvc, P < .05) was used within a priori-determined bilateral regions of interest (ROI). ROIs were chosen according to (1) previous knowledge on regional GMV reductions in patients with COPD, 10,12 (2) structural brain changes in chronic pain syndromes, [19][20][21][22][23] and (3) functional relevance of areas in the processing of dyspnea, 13,14 fear/anxiety, and fear-avoidance behavior, [15][16][17] and the transmission/regulation of nociceptive input. 18,28 Specifically, analyzed ROIs consisted of the anterior cingulate cortex (ACC), midcingulate cortex (MCC), insula, HC, thalamus, and AMYG.…”

“…9,10 However, results concerning gray matter volume (GMV) remain sparse and partly conflicting. 11,12 Notably, GMV reductions previously observed in patients with COPD included limbic and paralimbic brain areas such as cingulate cortex, insula, hippocampus (HC), and amygdala (AMYG), 10,12 which are not only involved in the processing of dyspnea, 13,14 but also in fear/anxiety and fear-avoidance behavior, [15][16][17] and in antinociception, that is, the downregulation of aversive nociceptive stimuli. 18 Comparable GMV reductions were demonstrated in patients chronically experiencing other aversive sensations, especially pain, [19][20][21][22][23] and these were associated with longer pain duration.…”