Effects of voluntary exercise duration on myocardial ischaemic tolerance, kinase signaling and gene expression

Exercise for myocardial ischemia-reperfusion injury: A systematic review and meta-analysis based on preclinical studies

The main pathological manifestation of coronary artery disease is myocardial injury caused by ischemia-reperfusion (IR) injury. Regular exercise reduces the risk of death during myocardial IR injury. The aim of this study was to describe the effects of various types of exercise on myocardial IR injury. Four electronic databases PubMed, Web of Science, Embase, and Cochrane Library were comprehensively searched from inception until February 2022, to identify studies relevant to the current review, using the method of combining subject and free words. Finally, 16 articles were included in the meta-analysis. Results showed that exercise training decreases the Myocardial infarct size compared to the control group (SMD = -2.6, 95 % CI [-3.53 to -1.67], P < 0.01); increasing the coronary blood flow (MD = 2.93, 95 % CI [2.41 to 3.44], P < 0.01), left ventricular developed pressure (SMD = 2.28, 95 % CI [0.12 to 4.43], P < 0.05), cardiac output (SMD = 1.22, 95 % CI [0.61 to 1.83], P < 0.01) compared to the control group. According to the descriptive analysis results also showed that exercise training increases the left ventricular ejection fraction, superoxide dismutase, manganese superoxide dismutase, glutathione peroxidase, copper-zinc superoxide dismutase, glutathione peroxidase, and decrease the creatine kinase, creatine kinase-MB, lactate dehydrogenase, Malondialdehyde, cardiac troponins T. Exercise can improve myocardial function after myocardial IR injury; however, further research is needed in combination with specific issues such as exercise mode, intensity, duration, and model issues.

ANKRD1 activates the Wnt signaling pathway by modulating CAV3 expression and thus promotes BMSC osteogenic differentiation and bone formation in ovariectomized mice

Bone marrow-derived mesenchymal stem cells (BMSCs) are considered promising materials for treating bone diseases such as osteoporosis (OP). This research explored the functions and molecular mechanism of ankyrin repeat domain 1 (ANKRD1) in BMSC osteogenesis. An OP model in mice was established by bilateral ovariectomy. Manipulation of ANKRD1 expression in BMSCs or femurs was achieved by lentivirus infection. Increased ANKRD1 expression was observed in BMSCs during osteogenic induction. Silencing of ANKRD1 impaired the osteogenesis of BMSCs, as shown by the decreased alkaline phosphatase (ALP) activity, osteogenic gene (Runx2, Col1a1, Bglap, and Spp1) expression, and mineralized formation. ANKRD1-mediated promotion of osteogenesis was also reproduced in mouse MC3T3-E1 preosteoblastic cells. Activation of Wnt/β-catenin signaling, a well-known osteogenic stimulus, was also impaired in ANKRD1-silenced BMSCs. Overexpression of ANKRD1 resulted in the opposite effects on osteogenesis and Wnt/β-catenin signaling. Mechanistic studies revealed that ANKRD1 modulated caveolin-3 (CAV3) expression by reducing CAV3 ubiquitination, and the knockdown of CAV3 impaired the functions of ANKRD1. Additionally, a very low level of ANKRD1 was observed in the BMSCs from OP mice. Rescue of ANKRD1 significantly restored osteogenic differentiation and Wnt signaling activation in BMSCs from ovariectomized mice. The results of micro-CT, H&E staining, and IHC staining showed that ANKRD1 also promoted bone formation and Wnt activation and ameliorated pathological alterations in the femurs of OP mice. Collectively, this study demonstrated that ANKRD1 plays an important role in regulating the osteogenic differentiation of BMSCs and is a promising target for the treatment of OP and other bone diseases.

The Role of SIRT3 in Exercise and Aging

The health benefits of regular exercise are well established. Nonetheless, the molecular mechanism(s) responsible for exercise-induced health benefits remain a topic of debate. One of the key cell-signaling candidates proposed to provide exercise-induced benefits is sirtuin 3 (SIRT3). SIRT3, an NAD+ dependent mitochondrial deacetylase, positively modulates many cellular processes, including energy metabolism, mitochondrial biogenesis, and protection against oxidative stress. Although the exercise-induced change in SIRT3 signaling is a potential mechanism contributing to the health advantages of exercise on aging, studies investigating the impact of exercise on SIRT3 abundance in cells provide conflicting results. To resolve this conundrum, this narrative review provides a detailed analysis of the role that exercise-induced changes in SIRT3 play in providing the health and aging benefits associated with regular physical activity. We begin with an overview of SIRT3 function in cells followed by a comprehensive review of the impact of exercise on SIRT3 expression in humans and other mammalians. We then discuss the impact of SIRT3 on aging, followed by a thorough analysis of the cell-signaling links between SIRT3 and exercise-induced adaptation. Notably, to stimulate future research, we conclude with a discussion of key unanswered questions related to exercise, aging, and SIRT3 expression.

Animal Models of Exercise From Rodents to Pythons

Acute and chronic animal models of exercise are commonly used in research. Acute exercise testing is used, often in combination with genetic, pharmacological, or other manipulations, to study the impact of these manipulations on the cardiovascular response to exercise and to detect impairments or improvements in cardiovascular function that may not be evident at rest. Chronic exercise conditioning models are used to study the cardiac phenotypic response to regular exercise training and as a platform for discovery of novel pathways mediating cardiovascular benefits conferred by exercise conditioning that could be exploited therapeutically. The cardiovascular benefits of exercise are well established, and, frequently, molecular manipulations that mimic the pathway changes induced by exercise recapitulate at least some of its benefits. This review discusses approaches for assessing cardiovascular function during an acute exercise challenge in rodents, as well as practical and conceptual considerations in the use of common rodent exercise conditioning models. The case for studying feeding in the Burmese python as a model for exercise-like physiological adaptation is also explored.

Short-term exercise-induced protection of cardiovascular function and health: why and how fast does the heart benefit from exercise?

Regular exercise training has potent and powerful protective effects against the development of cardiovascular disease. These cardioprotective effects of regular exercise training are partly explained through the effects of exercise on traditional cardiovascular risk factors and improvement in cardiac and vascular health, which take several weeks to months to develop. This review focuses on the observation that single bouts of exercise may also possess an underrecognized, clinically useful form of immediate cardioprotection. Studies, performed in both animals and humans, demonstrate that single or short-term exercise-induced protection (SEP) attenuates the magnitude of cardiac and/or vascular damage in response to prolonged ischaemia and reperfusion injury. This review highlights preclinical evidence supporting the hypothesis that SEP activates multiple pathways to confer immediate protection against ischaemic events, reduce the severity of potentially lethal ischaemic myocardial injury, and therefore act as a physiological first line of defence against injury. Given the fact that the extent of SEP could be modulated by exercise-related and subject-related factors, it is important to recognize and consider these factors to optimize future clinical implications of SEP. This review also summarizes potential effector signalling pathways (i.e. communication between exercising muscles to vascular/cardiac tissue) and intracellular pathways (i.e. reducing tissue damage) that ultimately confer protection against cardiac and vascular injury. Finally, we discuss potential future directions for designing adequate human and animal studies that will support developing effective SEP strategies for the (multi-)diseased and aged individual. KEY POINTS: Single or short-term exercise-induced protection (SEP) attenuates the magnitude of cardiac and/or vascular damage in response to prolonged ischaemia and reperfusion injury (IR injury). SEP activates multiple pathways to confer cardiac protection, which develops remotely at the site of the activated muscle by release of circulating molecules, which transfer towards activation of intramyocardial signalling that promotes cell survival during episodes of IR injury. SEP represents an attractive intervention in aged individuals and in those with co-morbidities. The immediate protection, low cost and simplicity to increase the 'dose' of SEP offers unique opportunities in the clinical applications of SEP.

Short term exercise‐induced protection of cardiovascular function and health: Why and how fast does the heart benefit from exercise?

Abstract

Regular exercise training has potent and powerful protective effects against the development of cardiovascular disease. These cardioprotective effects of regular exercise training are partly explained through the effects of exercise on traditional cardiovascular risk factors and improvement in cardiac and vascular health, which take several weeks to months to develop. This review focuses on the observation that single bouts of exercise may also possess an underrecognized, clinically useful form of immediate cardioprotection. Studies, performed in both animals and humans, demonstrate that single or short‐term exercise‐induced protection (SEP) attenuates the magnitude of cardiac and/or vascular damage in response to prolonged ischaemia and reperfusion injury. This review highlights preclinical evidence supporting the hypothesis that SEP activates multiple pathways to confer immediate protection against ischaemic events, reduce the severity of potentially lethal ischaemic myocardial injury, and therefore act as a physiological first line of defence against injury. Given the fact that the extent of SEP could be modulated by exercise‐related and subject‐related factors, it is important to recognize and consider these factors to optimize future clinical implications of SEP. This review also summarizes potential effector signalling pathways (i.e. communication between exercising muscles to vascular/cardiac tissue) and intracellular pathways (i.e. reducing tissue damage) that ultimately confer protection against cardiac and vascular injury. Finally, we discuss potential future directions for designing adequate human and animal studies that will support developing effective SEP strategies for the (multi‐)diseased and aged individual.

Key points

Single or short‐term exercise‐induced protection (SEP) attenuates the magnitude of cardiac and/or vascular damage in response to prolonged ischaemia and reperfusion injury (IR injury).

SEP activates multiple pathways to confer cardiac protection, which develops remotely at the site of the activated muscle by release of circulating molecules, which transfer towards activation of intramyocardial signalling that promotes cell survival during episodes of IR injury.

SEP represents an attractive intervention in aged individuals and in those with co‐morbidities. The immediate protection, low cost and simplicity to increase the ‘dose’ of SEP offers unique opportunities in the clinical applications of SEP.

AMPK activator O304 improves metabolic and cardiac function, and exercise capacity in aged mice

Age is associated with progressively impaired, metabolic, cardiac and vascular function, as well as reduced work/exercise capacity, mobility, and hence quality of life. Exercise exhibit positive effects on age-related dysfunctions and diseases. However, for a variety of reasons many aged individuals are unable to engage in regular physical activity, making the development of pharmacological treatments that mimics the beneficial effects of exercise highly desirable. Here we show that the pan-AMPK activator O304, which is well tolerated in humans, prevented and reverted age-associated hyperinsulinemia and insulin resistance, and improved cardiac function and exercise capacity in aged mice. These results provide preclinical evidence that O304 mimics the beneficial effects of exercise. Thus, as an exercise mimetic in clinical development, AMPK activator O304 holds great potential to mitigate metabolic dysfunction, and to improve cardiac function and exercise capacity, and hence quality of life in aged individuals.