Exercise and Organ Cross Talk

Swimming induces physiological cardioprotection associated with pro-growth versus anti-inflammatory influences in extracardiac organs

Physical activity improves myocardial structure, function, and resilience via complex, incompletely defined mechanisms. We explored the effects of 1- to 2-wk swim training on cardiac and systemic phenotype in young male C57Bl/6 mice. Two-week forced swimming (90 min twice daily) resulted in cardiac hypertrophy (22% increase in heart:body weight, P < 0.01), with improved inotropy (22% higher left ventricular +dP/dt, P < 0.01) and functional tolerance to ischemia-reperfusion (I-R) (40%-50% reductions in stunning and diastolic dysfunction, P < 0.01; without changes in cell death assessed from enzyme loss) in Langendorff perfused hearts. Initial Western immunoblot analysis indicated no shifts in cardiac expression of determinants of autophagy (LC3A/B), mitochondrial biogenesis/dynamics (PGC-1α, MFN-1, and OPA-1), or stress signaling (caveolin-3 and GSK-3β). Furthermore, no changes in cardiac cytokines (IL-1b, IL-6, IL-10, IL-12, GM-CSF, TNF-α, and IFN-γ) were detected in multiplex immunoassays. Exploratory profiling of RTK phosphorylation provided evidence for moderately increased activity of receptors involved in cardiac/coronary growth and protection (insulin, IGF-1, FGF R2, Tie-2, PDGFβ, and EphB4), together with a fall in M-CSF R and ephrin sub-type receptor phosphorylation. Swimming increased growth factor while reducing inflammatory mediators across extracardiac tissues [brain, pancreas, thymus, lymph nodes, and white adipose tissue (WAT)]. This included a pattern of increased LIF, VEGF, and pentraxin-2 versus reduced CXCL2/MIP-2a, chitinase 3-like 1, CCL6, MMP9, CD40/TNFRSF5, and IGFBP6 in multiple tissues, and a shift to a pro-browning profile in WAT. In summary, swimming produces integrated systemic benefits, improving cardiac growth, inotropy, and resilience in association with increased growth factor and reduced inflammatory and lipogenic mediators in multiple tissues.NEW & NOTEWORTHY Swimming may induce cardiac and systemic benefits distinct from other modes of physical activity. We show that 2-wk forced swim training increases cardiac growth, contractility, and functional resilience to ischemia in hearts of male mice. This is associated with increased growth factor levels and reduced inflammatory and lipogenic protein profiles in peripheral tissues.

Effects of exercise by type and duration on quality of life in patients with digestive system cancers: A systematic review and network meta-analysis

BACKGROUND

There is scant evidence regarding the effects of exercise type and duration on quality of life (QoL) in digestive system cancer (DSC) survivors. We aim to investigate the optimal type and duration of exercises to improve QoL for DSC survivors through a systematic review and network meta-analysis.

METHODS

A systematic literature search of PubMed, Embase, and Web of Science was performed. Eligibility for study inclusion was limited to studies that were randomized controlled trials involving all kinds of exercise in adult patients with DSCs, and the comparator was in standard care or other types of exercise. The primary outcome was QoL, including general health, physical health, mental health, and role function. Secondary outcomes included cancer-related symptoms such as fatigue, insomnia, depression, anxiety, and duration of hospital stay. The network meta-analyses were performed using a random-effect model.

RESULTS

The analysis included 32 eligible articles and a total of 2558 participants. Our primary outcome indicated that short-term aerobic exercise significantly enhanced general health (standardized mean differences (SMDs) = 0.66, 95% credible intervals (CrIs): 0.05 to 1.30, and also contributed to a better mental health (SMD = 0.37, 95%CrI: -0.06 to 0.81 and role function (SMD = 0.48, 95%CrI: -0.27 to 1.20). Although without significant changes, short-term resistance exercise tends to increase the physical health of patients with DSCs (SMD = 0.69, 95%CrI: -0.07 to 1.50) and effective in alleviating fatigue (SMD = -0.77, 95%CrI: -1.50 to 0.01). Short-term aerobic exercise was related to a lower score of insomnia (SMD = -1.20, 95%CrI: -2.40 to 0.06), depression (SMD = -0.51, 95%CrI: -1.50 to 0.45), and anxiety (SMD = -0.45, 95%CrI: -1.30 to 0.34). All types of exercise related to a trend of declined hospital stays (-0.87 to -5.00 days). Long-term resistance exercise, however, was negatively associated with general health (SMD = -0.33, 95%CrI: -1.70 to 1.00), physical health (SMD = -0.18, 95%CrI: -1.30 to 0.90), and role function (SMD = -1.20, 95%CrI: -2.50 to 0.11).

CONCLUSION

This study suggests that short-term aerobic exercise, with or without resistance exercise programs, enhances QoL (especially for general health) as well as relieves cancer-related symptoms for DSC survivors, while long-term resistance exercise may have negative effects, and thus should be adopted cautiously. These results provide important evidence for the management of DSCs.

Obesity I: Overview and molecular and biochemical mechanisms

Obesity is a chronic, relapsing condition characterized by excess body fat. Its prevalence has increased globally since the 1970s, and the number of obese and overweight people is now greater than those underweight. Obesity is a multifactorial condition, and as such, many components contribute to its development and pathogenesis. This is the first of three companion reviews that consider obesity. This review focuses on the genetics, viruses, insulin resistance, inflammation, gut microbiome, and circadian rhythms that promote obesity, along with hormones, growth factors, and organs and tissues that control its development. It shows that the regulation of energy balance (intake vs. expenditure) relies on the interplay of a variety of hormones from adipose tissue, gastrointestinal tract, pancreas, liver, and brain. It details how integrating central neurotransmitters and peripheral metabolic signals (e.g., leptin, insulin, ghrelin, peptide YY_3-36) is essential for controlling energy homeostasis and feeding behavior. It describes the distinct types of adipocytes and how fat cell development is controlled by hormones and growth factors acting via a variety of receptors, including peroxisome proliferator-activated receptor-gamma, retinoid X, insulin, estrogen, androgen, glucocorticoid, thyroid hormone, liver X, constitutive androstane, pregnane X, farnesoid, and aryl hydrocarbon receptors. Finally, it demonstrates that obesity likely has origins in utero. Understanding these biochemical drivers of adiposity and metabolic dysfunction throughout the life cycle lends plausibility and credence to the "obesogen hypothesis" (i.e., the importance of environmental chemicals that disrupt these receptors to promote adiposity or alter metabolism), elucidated more fully in the two companion reviews.

The wonder exerkines-novel insights: a critical state-of-the-art review

Several benefits can be acquired through physical exercise. Different classes of biomolecules are responsible for the cross-talk between distant organs. The secretome of skeletal muscles, and more widely the field of organokines, is ever-expanding. “Exerkine” has emerged as the umbrella term covering any humoral factors secreted into circulation by tissues in response to exercise. This review aims at describing the most interesting exerkines discovered in the last 3 years, which are paving the way for both physiological novel insights and potential medical strategies. The five exerkines identified all play a significant role in the healthy effect of exercise. Specifically: miR-1192, released by muscles and myocardium into circulation, by modulating cardioprotective effect in trained mice; miR-342-5p, located into exosomes from vascular endothelial cells, also a cardioprotective miRNA in trained young humans; apelin, released by muscles into circulation, involved in anti-inflammatory pathways and muscle regenerative capacity in rats; GDF-15, released into circulation from yet unknown source, whose effects can be observed on multiple organs in young men after a single bout of exercise; oxytocin, released by myoblasts and myotubes, with autocrine and paracrine functions in myotubes. The systemic transport by vesicles and the crosstalk between distant organs deserve a deep investigation. Sources, targets, transport mechanisms, biological roles, population samples, frequency, intensity, time and type of exercise should be considered for the characterization of existing and novel exerkines. The “exercise is medicine” framework should include exerkines in favor of novel insights for public health.