Synergistic effects of low-level stress and a Western diet on metabolic homeostasis, mood, and myocardial ischemic tolerance

Eugene F. Du Toit*, Wei Shan Tai, Amanda Cox, Dylan O'Connor, Tia A. Griffith, Tessa Helman, Lauren Wendt, Jason N. Peart, Nicolas J. C. Stapelberg, John P. Headrick

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

5 Citations (Scopus)

Abstract

How low-level psychological stress and overnutrition interact in influencing cardiometabolic disease is unclear. Mechanistic overlaps suggest potential synergies; however, findings are contradictory. We test whether low-level stress and Western diet (WD) feeding synergistically influence homeostasis, mood, and myocardial ischemic tolerance. Male C57BL6/J mice were fed a control diet or WD (32%/57%/11% calories from fat/carbohydrates/protein) for 12 wk, with subgroups restrained for 30 min/day over the final 3 wk. Metabolism, behavior, tolerance of perfused hearts to ischemia-reperfusion (I/R), and cardiac "death proteins" were assessed. The WD resulted in insignificant trends toward increased body weight (+5%), glucose (+40%), insulin (+40%), triglycerides (+15%). and cholesterol (+20%) and reduced leptin (-20%) while significantly reducing insulin sensitivity [100% rise in homeostasis model assessment of insulin resistance (HOMA-IR). P < 0.05]. Restraint did not independently influence metabolism while increasing HOMA-IR a further 50% (and resulting in significant elevations in insulin and glucose to 60-90% above control) in WD mice (P < 0.05), despite blunting weight gain in control and WD mice. Anxiogenesis with restraint or WD was nonadditive, whereas anhedonia (reduced sucrose consumption) only arose with their combination. Neuroinflammation markers (hippocampal TNF-alpha, Il-1b) were unchanged. Myocardial I/R tolerance was unaltered with stress or WD alone, whereas the combination worsened dysfunction and oncosis [lactate dehydrogenase (LDH) efflux]. Apoptosis (nucleosome accumulation) and death protein expression (BAK, BAX, BCL-2, RIP-1, TNF-alpha, cleaved caspase-3, and PARP) were unchanged. We conclude that mild, anxiogenic yet cardio-metabolically "benign" stress interacts synergistically with a WD to disrupt homeostasis, promote anhedonia (independently of neuroinflammation), and impair myocardial ischemic tolerance (independently of apoptosis and death protein levels).

Original languageEnglish
Pages (from-to)R347-R357
Number of pages11
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume319
Issue number3
DOIs
Publication statusPublished - Sep 2020

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