학술논문

Dysfunction of inflammation-resolving pathways is associated with exaggerated postoperative cognitive decline in a rat model of the metabolic syndrome.
Document Type
article
Source
Molecular medicine (Cambridge, Mass.). 18(12)
Subject
Hippocampus
Spleen
Macrophages
Animals
Rats
Disease Models
Animal
Inflammation
Choline
Leukotriene B4
Lipoxins
Receptors
Adrenergic
beta-2
Anti-Inflammatory Agents
Lymphocyte Count
Postoperative Period
Physical Conditioning
Animal
Cognition Disorders
Signal Transduction
Cell Polarity
Male
T-Lymphocytes
Regulatory
CD3 Complex
Metabolic Syndrome
Disease Models
Animal
Receptors
Adrenergic
beta-2
Physical Conditioning
T-Lymphocytes
Regulatory
Immunology
Medicinal and Biomolecular Chemistry
Biochemistry and Cell Biology
Language
Abstract
The cholinergic antiinflammatory pathway (CAP), which terminates in the spleen, attenuates postoperative cognitive decline (PCD) in rodents. Surgical patients with metabolic syndrome exhibit exaggerated and persistent PCD that is reproduced in postoperative rats selectively bred for easy fatigability and that contain all features of metabolic syndrome (low-capacity runners [LCRs]). We compared the CAP and lipoxin A(4) (LXA(4)), another inflammation-resolving pathway in LCR, with its counterpart high-capacity runner (HCR) rats. Isoflurane-anesthetized LCR and HCR rats either underwent aseptic trauma involving tibial fracture (surgery) or not (sham). At postoperative d 3 (POD3), compared with HCR, LCR rats exhibited significantly exaggerated PCD (trace fear conditioning freezing time 43% versus 57%). Separate cohorts were killed at POD3 to collect plasma for LXA4 and to isolate splenic mononuclear cells (MNCs) to analyze CAP signaling, regulatory T cells (Tregs) and M2 macrophages (M2 Mφ). Under lipopolysaccharide (LPS) stimulation, tumor necrosis factor (TNF)-α produced by splenic MNCs was 117% higher in LCR sham and 52% higher in LCR surgery compared with HCR sham and surgery rats; LPS-stimulated TNF-α production could not be inhibited by an α7 nicotinic acetylcholine receptor agonist, whereas inhibition by the β(2) adrenergic agonist, salmeterol, was significantly less (-35%) than that obtained in HCR rats. Compared to HCR, sham and surgery LCR rats had reduced β(2) adrenergic receptor-expressing T lymphocytes (59%, 44%), Tregs (47%, 54%) and M2 Mφ (45%, 39%); surgical LCR rats' hippocampal M2 Mφ was 66% reduced, and plasma LXA4 was decreased by 120%. Rats with the metabolic syndrome have ineffective inflammation-resolving mechanisms that represent plausible reasons for the exaggerated and persistent PCD.