The Transient Cardioprotective Effects of Training and Subsequent De-training and Re-training of Acute Voluntary Wheel-running Mice

The Transient Cardioprotective Effects of Training and Subsequent De-training and Re-training of Acute Voluntary Wheel-running Mice

Conclusion: Our results demonstrate that lesion eccentricity in human coronary arteries affects mechanical forces throughout cardiac cycle. http://dx...

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Conclusion: Our results demonstrate that lesion eccentricity in human coronary arteries affects mechanical forces throughout cardiac cycle. http://dx.doi.org/10.1016/j.hlc.2012.05.130 121 The Transient Cardioprotective Effects of Training and Subsequent De-training and Re-training of Acute Voluntary Wheel-running Mice B. Budiono 1,∗ , L. See Hoe 1 , J. Peart 1 , S. Sabapathy 1 , K. Ashton 2 , L. Haseler 1 , J. Headrick 1 1 Heart

Foundation Research Centre, Griffith Health Institute, Griffith University, Australia 2 Faculty of Health Sciences and Medicine, Bond University, Australia Introduction: Our group has recently shown that even relatively short periods of voluntary activity wheel running (seven-days) in previously untrained mice can produce a significant cardioprotective effect from the damaging effects of ischaemia/reperfusion (I/R). Timecourse and detraining/re-training studies are currently underway to understand the temporal nature of this protection. Approach and findings: Functional responses of isolated mouse hearts (8–10 weeks old) subject to I/R (25 min ischaemia/45 min reperfusion) via Langendorff perfusion showed that 14-days of wheel running improved left ventricular developed pressure recovery from 48% to 58%. Past experiments demonstrate that detraining occurs rapidly, returning to baseline levels after seven-days. Our new results show three days of re-training returned protection back to 56%. To explain underlying protective mechanisms, genomic and proteomic expression studies were performed. Whole genome microarray and subsequent qRT-PCR show an upregulation of metabolic function and conversely an attenuation of inflammatory markers. We then hypothesised that this unique mode of animal exercise may exert its cardioprotective effect via traditional pro-survival signaling pathways (Akt, Erk1/2) and attenuating pro-death (GSK3b) kinase expression. Preliminary protein expression studies (total and phosphorylated) performed via Western Immunoblotting showed modest activation of protective mechanisms via Akt and Erk1/2, and attenuation of GSK3b. Conclusions: Findings to date have shown that the protective effects of 14-days wheel running is diminished with seven-days of detraining (wheel-locked), but is returned after three days of re-training. This study confirms the need for regular activity to maintain protective signaling in the heart. Future directions: Prospective studies will be focused on determining the relative importance of the multiple protective pathways activated by exercise. Furthermore, comparison studies with established models such as forced swim training (inducing physiological hypertrophy) and/or dietary influences are being planned. http://dx.doi.org/10.1016/j.hlc.2012.05.131

CSANZ 2012 Abstracts

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122 The Utility of Exercise Stress Test in the Risk Stratification of Women Aged 40–54 Years with Suspected Intermediate Risk Acute Coronary Syndrome A. Lamanna 1,∗ , A. Scott 1 , J. Bilesky 1,2 , L. Cullen 2 , J. Greenslade 2 , A. Brown 2 , C. Denaro 3 , W. Parsonage 1 1 Cardiology Department, Royal Brisbane and Women’s Hospi-

tal, Australia 2 Department

of Emergency Medicine, Royal Brisbane and Women’s Hospital, Australia 3 Department of Internal Medicine, Royal Brisbane and Women’s Hospital, Australia Background: Exercise stress test (EST) is frequently used to risk-stratify patients with suspected intermediate-risk acute coronary syndrome (ACS) who have serial negative cardiac biomarkers and non-diagnostic ECG. However, EST is thought to be less accurate in women because of lower prevalence of coronary artery disease (CAD) and higher incidence of false positive test. The utility of EST in women aged 40–54 years with suspected intermediate-risk ACS was evaluated. Method: An analysis of EST performed on women aged 40–54 years referred through the Royal Brisbane and Women’s Hospital Emergency Department chest pain pathway between November 2005 and January 2011 was undertaken. The positive predictive value (PPV) for the composite endpoint of obstructive CAD and revascularisation was evaluated. Results: There were 1821 patients aged 40–54 years who underwent EST. Of these, 769 (42.2%) were women (age = 47.6 ± 4.2 years). Twenty-four women had positive EST (positive EST incidence = 3.1%). Of these only two were true positive (PPV of EST in women aged 40–54 years = 8.3%). All of the positive EST in women younger than 50 years were found to be false positive following further testing. The incidence of positive EST in males (age = 46.6 ± 4.3 years) was similar (3.9% of 1052 EST, pvalue = 0.3). In comparison, the PPV of EST in males aged 40–54 years was 34.8% (p-value < 0.001). Conclusion: The PPV of EST is low in women aged 40–54 years. EST has limited utility in risk stratification of women in this age group with suspected intermediate risk ACS, especially in women younger than 50 years. http://dx.doi.org/10.1016/j.hlc.2012.05.132 123 Treatment Delay Components for STEMI Patients Undergoing Primary PCI: Four Years of Progress D. Murdoch ∗ , M. Yudi, A. Sweeny, M. Trikilis, R. Jayasinghe Gold Coast Hospital, Australia Background: Timely reperfusion is recommended for patients with ST-segment elevation myocardial infarction (STEMI), and there is increasing recognition that systemwide factors should be addressed with the goal of reducing overall treatment delay times. The Gold Coast Hospital is a

ABSTRACTS

Heart, Lung and Circulation 2012;21:S1–S142