Hovens IB, van Leeuwen BL, Falcao-Salles J, de Haan JJ, Schoemaker RG. Enteral enriched nutrition to prevent cognitive dysfunction after surgery; a study in rats.
Brain Behav Immun Health 2021;
16:100305. [PMID:
34589797 PMCID:
PMC8474614 DOI:
10.1016/j.bbih.2021.100305]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/17/2021] [Accepted: 07/24/2021] [Indexed: 11/26/2022] Open
Abstract
Background
Inflammation plays an important role in postoperative cognitive dysfunction (POCD), particularly in elderly patients. Enteral enriched nutrition was shown to inhibit the response on inflammatory stimuli. Aim of the present study was to explore the therapeutic potential of enteral enriched nutrition in our rat model for POCD. The anticipated mechanism of action was examined in young rats, while responses in the target group of elderly patients were evaluated in old rats.
Methods
Male 3 and 23 months old Wistar rats received a bolus of enteral fat/protein-enriched nutrition 2 h and 30 min before surgery. The inflammatory response was evaluated by systemic inflammation markers and brain microglia activity. Additionally, in old rats, the role of the gut-brain axis was studied by microbiome analyses of faecal samples. Days 9–14 after surgery, rats were subjected to cognitive testing. Day 16, rats were sacrificed and brains were collected for immunohistochemistry.
Results
In young rats, enriched nutrition improved long-term spatial learning and memory in the Morris Water Maze, reduced plasma IL1-β and VEGF levels, but left microglia activity and neurogenesis unaffected. In contrast, in old rats, enriched nutrition improved short-term memory in the novel object- and novel location recognition tests, but impaired development of long-term memory in the Morris Water Maze. Systemic inflammation was not affected, but microglia activity seemed even increased. Gut integrity and microbiome were not affected.
Conclusion
Enteral enriched nutrition before surgery in young rats indeed reduced systemic inflammation and improved cognitive performance after surgery, whereas old rats showed a mixed favorable/unfavorable cognitive response, without effect on systemic inflammation. Anti-inflammatory effects of enriched nutrition were not reflected in decreased microglia activity. Neither was an important role for the gut-brain axis observed. Since the relatively straight forward effects of enriched nutrition in young rats could not be shown in old rats, as indicated by a mixed beneficial/detrimental cognitive outcome in the latter, caution is advised by translating effects seen in younger patients to older ones.
Enriched nutrition reduced inflammation after surgery in young rats.
Enriched nutrition improved postoperative cognitive outcome in young rats.
Enteral enriched nutrition did not inhibit neuroinflammation.
Effects in young rats do not predict effects in old rats.
Enteral enriched nutrition caused mixed improved/declined cognition in old rats.
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