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

Jing Li,Guang-He Fei

doi:10.1186/1465-9921-14-140

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.

Highlights

Cognitive impairment has been found in chronic obstructive pulmonary disease (COPD) patients
The hippocampal volume was positively correlated with the mini mental state examination (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)
It was 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)

Summary

Introduction

Cognitive impairment has been found in chronic obstructive pulmonary disease (COPD) patients. Chronic obstructive pulmonary disease (COPD) is a primary airway inflammatory disease characterized by irreversible airflow limitation which results in hypoxemia and hypercapnia. It is realized as a complex multi-component disorder [1,2,3,4]. The hippocampus which is located inside the medial temporal lobe is a major component of the brain It contains two main interlocking parts (Ammon’s horn and the dentate gyrus) and four histological divisions (cornu ammonis 1 (CA1), CA2, CA3 and CA4). The question arises as to whether detectable structural changes of hippocampal volume occur in COPD patients

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Discussion

Conclusion