A large number of data suggest that caloric restriction (CR) has a protective effect on myocardial ischemia/reperfusion injury (I/R) in the elderly. However, the mechanism is still unclear. In this study, we created the I/R model in vivo by ligating the mice left coronary artery for 45 min followed by reperfusion. C57BL/6J wild-type mice were randomly divided into a young group fed ad libitum (y-AL), aged fed ad libitum (a-AL) and aged calorie restriction group (a-CR, 70% diet restriction), and fed for 6 weeks. The area of myocardial infarction was measured by Evan’s blue-TTC staining, plasma cholesterol content quantified by ELISA, fatty acids and glucose measured by Langendorff working system, as well as protein expression of AMPK/SIRT1/PGC1a signaling pathway related factors in myocardial tissue detected by immunoblotting. Our results showed that CR significantly reduced infarct size in elderly mice after I/R injury, promoted glycolysis regardless of I/R injury, and restored myocardial glucose uptake in elderly mice. Compared with a-AL group, CR significantly promoted the expression of p-AMPK, SIRT1, p-PGC1a, and SOD2, but decreased PPARγ expression in aged mice. In conclusion, our results suggest that CR protects elderly mice from I/R injury by altering myocardial substrate energy metabolism via the AMPK/SIRT1/PGC1a pathway.

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This paper is to explore RF characteristics of the graphene for antenna applications. The electrical tunability of the graphene material with applied fields and chemical means can be used for the innovative designs of tunable and reconfigurable antennas and antenna arrays at mmw and Thz wave range, which is verified by a model graphene patch antenna around 1THz in this paper.

BACKGROUND: Intraoperative goal-directed fluid therapy(GDFT) have been reported to reduce postoperative complications of the patients undergoing major abdominal surgery. The clinical benefits of pleth variability index(PVI) directed fluid management for gastrointestinal(GI) surgical patients remain unclear. Therefore, this study aimed to evaluate the impact of GDFT based on the PVI on elderly GI surgical outcomes. METHODS: This randomised controlled trial was conducted in two university teaching hospitals from November 2017 to December 2020. A total of 220 older adults undergoing GI surgery were randomised to the GDFT group or conventional fluid therapy（CFT）group (n=110 each). The primary outcome was a composite of complications within 30 postoperative days. The secondary outcomes were cardiopulmonary complications , time to first flatus, postoperative nausea and vomiting (PONV)and postoperative length of stay(PLOS) RESULTS: The total volumes of fluid administered were less in the GDFT group than in the CFT group (2500(2000, 3100)vs2075(1900, 2600), P=0.008). In intention-to-treat analysis, we found no difference in overall complications between groups: (41.3%) (CFT group) vs (43.0%) (GDFTgroup) (OR=0.935; 95% CI, 0.541-1.615; P=0.809). The proportion of cardiopulmonary complication was higher in CFT group compared with GDFT group(19.2% vs 8.4%; OR=2.593, 95% CI, 1.120-5.999; P =0.022 ). No other differences were identified between two groups. CONCLUSIONS: Among elderly patients undergoing GI surgery, intraoperative GDFT based on the simple and noninvasive PVI did not reduce the occurrence of composite postoperative complications but was associated with a lower cardiopulmonary complication compared with usual fluid management.

Ischemic tolerance of heart decreases with age. Caloric restriction (CR) is the most reliable intervention to extend lifespan and prevent age-related disorders. We have revealed that both AMPK and SIRT1 signaling pathways are involved in the impairments occurred in aged hearts. We hypothesize that cardiac AMPK-SIRT1 signaling cascade mediates the increased tolerance of aged heart to ischemic insults by caloric restriction. Aged (18-20 months) mice were divided into 2 groups: al libitum (AL) food intake group and caloric restriction (diet 70% of standard food intake for 6 weeks) (CR) group. Each group was divided into sham operations and ischemia/reperfusion (I/R) semi-groups. I/R groups were subjected to ligation of left anterior descending coronary artery for 30 min of ischemia and 24 hours of reperfusion. The body fat composition was significantly decreased in CR group vs. AL group, moreover, the maximum of oxygen consumption was significantly improved in CR group vs. AL group. Importantly, there is a significantly smaller myocardial infarction size induced by ischemia (30 min) and reperfusion (24 hours) in CR group than that in AL group. The immunoblotting results demonstrated that the impaired ischemic AMPK activation in AL group was augmented in CR group, and the AMPK downstream acetyl CoA carboxylase (ACC) phosphorylation and PGC-1alpha phosphorylation were also augmented in CR vs. AL group in response to ischemic insults. Intriguingly, the expression levels of a longevity protein, SIRT1, were upregulated in the heart of CR group vs. the corresponding AL group. Furthermore, the inducible cardiomyocyte SIRT1 deficiency mice (icSIRT1 KO) did not show any recused impaired ischemic AMPK activation in the CR group vs. icSIRT1 KO AL group. Thus, caloric restriction is a non-pharmacological approach to increase the tolerance of aged heart to ischemic insults. The AMPK-SIRT1 signaling cascade plays a critical role in the cardiac CR benefits in the elderly. Disclosure Z. Guo: None. T. Rousselle: None. J. Li: None.