Long-term voluntary exercise, representing habitual exercise, lowers visceral fat and alters plasma amino acid levels in mice

Gradual increase in energy intake over 8 weeks with voluntary wheel running limits body weight change in male rats

The influence of appetite and energy intake (EI) on energy compensation in response to chronic exercise remains poorly understood. This study examined the temporal impact of habitual exercise on EI and the homeostatic appetite regulators that influence energy compensation. Twelve-week-old male Sprague Dawley rats (n 30) fed an AIN-93M diet were randomised into one of three groups: (1) sedentary control (SED); (2) voluntary wheel exercise (EX) and (3) sedentary, weight-matched to aerobic exercise (SED-WM) for 8 weeks. Measures of EI, body weight and adiposity were assessed. Appetite-regulating hormones acyl ghrelin, active glucagon-like peptide (GLP)-1, leptin and insulin were measured in response to an oral glucose tolerance test. Rats with running wheels completed an average of 192 km over 8 weeks. While EI was initially reduced in EX, EI gradually increased with exercise training after week 1 (P < 0·05). Body weight was lower in EX relative to SED from weeks 3 to 5 but did not differ at the end of the study. Fat mass and long-term satiety hormones leptin and insulin were lower in EX (P < 0·05). No differences were observed in concentrations of the satiety hormone active GLP-1 or the orexigenic hormone acyl ghrelin. Short-term homeostatic regulators of appetite do not appear to be altered with exercise training. The reduction in adiposity and associated decrease in tonic satiety hormones leptin and insulin are likely contributors to the coupling of energy expenditure with EI over time with voluntary exercise.

The association of visceral fat metabolism score with hyperuricemia-evidence from NHANES 1999-2018

Objectives

Despite substantial evidence that visceral obesity is an epidemiological risk factor for hyperuricemia (HUA), studies on the connection between the Metabolic Score for Visceral Fat (METS-VF) and HUA remain insufficient. This research focused on METS-VF's potential role as a risk factor for HUA.

Methods

Notably, 8,659 participants from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018 were enrolled in this study. Propensity score matching (PSM), multivariate logistic regression analysis, subgroup analysis, interaction test, and restricted cubic spline (RCS) analysis were implemented to identify the correlation between METS-VF and HUA.

Results

In the fully adjusted model, the results of the multiple logistic regression analysis indicated that METS-VF was related to an elevated prevalence of HUA [before PSM: odds ratio (OR) = 3.51 (2.88, 4.27), p < 0.001; after PSM: OR = 2.90 (2.36, 3.58), p < 0.001]. In RCS analysis, a non-linear positive correlation was observed between METS-VF and the incidence of HUA (before PSM: p-non-linear <0.001; after PSM: p-non-linear = 0.0065). Subgroup analysis and interaction tests revealed that the impact of METS-VF on HUA was modified by sex and ethnicity.

Conclusion

There is a significant positive correlation between METS-VF and HUA in adults in the United States. METS-VF could serve as a valuable metric for assessing the development and progression of HUA.

8-Week Kaempferia parviflora Extract Administration Improves Submaximal Exercise Capacity in Mice by Enhancing Skeletal Muscle Antioxidant Gene Expression and Plasma Antioxidant Capacity

Black ginger (Kaempferia parviflora) extract (KPE) is extracted from a ginger family plant grown in Thailand. The polyphenolic components have potential antioxidant effects and have been reported to enhance exercise performance. However, the impact of long-term KPE administration combined with long-term training on the endurance exercise performance of healthy individuals has not been fully studied. In this study, a healthy mouse model was used to investigate the effects of 8 weeks KPE administration and voluntary wheel running on the submaximal endurance exercise capacity and its mechanism. The results showed that 8 weeks of KPE administration significantly enhanced the submaximal endurance exercise capacity of mice and extended the daily voluntary wheel running distance. By measuring oxidative stress markers in plasma and the mRNA expression of antioxidant genes in skeletal muscle, we found that KPE significantly increased plasma antioxidant levels and activated the Nrf2 (Nuclear factor erythroid 2-related factor 2)/ARE (Antioxidant Response Element) pathway and its downstream antioxidant genes expression in skeletal muscle. These results suggest that KPE may enhance the antioxidant capacity of plasma and skeletal muscle by activating the Nrf2-ARE-centered antioxidant pathway, thereby increasing the daily running distance and improving the submaximal endurance exercise capacity of mice.

Using approach latency and anticipatory behaviour to assess whether voluntary playpen access is rewarding to laboratory mice

Laboratory mice are typically housed in “shoebox" cages that limit the expression of natural behaviours. Temporary access to more complex environments (playpens) may improve their welfare. We aimed to assess if access to playpens is rewarding for conventionally-housed mice and to document mouse behaviour during playpen access. Female C57BL/6J, BALB/cJ, and DBA/2J mice were provided temporary access to a large enriched playpen three times per week; control mice remained in their home cages. We measured latency to enter playpens and anticipatory behaviour to determine if access was rewarding, and recorded mouse behaviour during playpen sessions. Over time, playpen mice entered the playpen more quickly; latency declined from 168 ± 22 to 13 ± 2 s over the 14-d trial. As expected, playpen mice showed an increase in anticipatory behaviour before playpen access (mean ± SE = 19.7 ± 2.6 behavioural transitions), while control mice showed no change in anticipatory behaviour relative to baseline values (2.4 ± 1.6 transitions). Mice in the playpen performed more ambulatory behaviours than control mice who remained in home cages (21.5 ± 0.7 vs 6.9 ± 1.1 observations of 25 total observations). We conclude that conventionally-housed mice find voluntary playpen access rewarding, and suggest this as a useful option for providing laboratory mice with access to more complex environments.

Effects of lifelong exercise and aging on the blood metabolic fingerprint of rats

Regular exercise is an important part of a healthy lifestyle, as it helps maintain a healthy weight and reduces the risk of chronic diseases. We explored the effects of lifelong exercise and aging on rat metabolism through a metabolomics approach. Thirty-six rats were divided into four equal groups: exercise during the 1st half of life (3-12 months), lifelong exercise (3-21 months), no exercise, and exercise during the 2nd half of life (12-21 months). Exercise consisted in swimming for 20 min, five times a week. Blood samples collected at 3, 12, and 21 months of life were analysed by ¹H NMR spectroscopy. The groups that exercised during the 2nd half of life weighed less than the groups that did not. Exercise had an orexigenic effect during the 1st half and an anorexigenic effect during the 2nd half. Multivariate analysis showed a clear discrimination between ages when groups were treated as one and between the exercising and non-exercising groups at 12 months. Univariate analysis showed many effects of aging and some effects of exercise on metabolites involved in carbohydrate, lipid and protein metabolism. Especially during the 1st half, exercise had anabolic effects, whereas aging had catabolic effects on amino acid metabolism. In two cases (glycine and succinate), exercise (especially during the 1st half) mitigated potentially harmful effects of aging. The higher values of succinate and the lower values of lactate during the 1st half in the exercising groups suggest increased oxidative metabolism. In conclusion, moderate-intensity exercise for life or half-life had strong and potentially healthful effects on body weight and (partly) appetite, as well as on some blood metabolites. The effects of aging on the rat blood metabolome seemed to be stronger than those of exercise.

CC002/Unc females are mouse models of exercise-induced paradoxical fat response

Exercise results in beneficial health outcomes and protects against a variety of chronic diseases. However, U.S. exercise guidelines recommend identical exercise programs for everyone, despite individual variation in responses to these programs, including paradoxical fat gain. Experimental models of exercise-induced paradoxical outcomes may enable the dissection of underlying physiological mechanisms as well as the evaluation of potential interventions. Whereas several studies have identified individual mice exhibiting paradoxical fat gain following exercise, no systematic effort has been conducted to identify and characterize models of paradoxical response. Strains from the Collaborative Cross (CC) genetic reference population were used due to its high levels of genetic variation, its reproducible nature, and the observation that the CC is a rich source of novel disease models, to assess the impact genetic background has on exercise responses. We identified the strain CC002/Unc as an exercise-induced paradoxical fat response model in a controlled voluntary exercise study across multiple ages in female mice. We also found sex and genetic differences were consistent with this pattern in a study of forced exercise programs. These results provide a novel model for studies to determine the mechanisms behind paradoxical metabolic responses to exercise, and enable development of more rational personalized exercise recommendations based on factors such as age, sex, and genetic background.

Former very preterm infants show alterations in plasma amino acid profiles at a preschool age

BACKGROUND

Amino acid analysis is a valuable tool for cardiovascular risk assessment. Preterm infants display plasma amino acid changes in the newborn period. Whether these changes persist is unknown to date. The aim of this study was to assess whether former very preterm infants (VPI) show alterations in amino acid patterns indicative of an unfavorable cardiovascular risk profile at a preschool age.

METHODS

From 5-7 y-old children born at term or <32 wk gestation (VPI) were included in the study. Plasma amino acid concentrations were determined after an overnight fast.

RESULTS

29 former term infants and 79 former VPI were included in the study. Former VPI showed changes in various plasma amino acids including glutamine, arginine, citrulline, tryptophan, glutamate, ornithine, and taurine. Branched-chain amino acids were lower, alanine/lysine ratios significantly higher in the preterm population.

CONCLUSION

Former VPI show altered plasma amino acid profiles indicative of a dualistic cardiovascular risk profile (e.g., potentially beneficial elevations in citrulline, arginine, glutamine, and tryptophan, but also raised alanine/lysine ratios, low ornithine and taurine levels) at a preschool age. Whether this is associated with an adverse cardiovascular outcome has to be addressed by future studies. Long-term cardiometabolic follow-up of VPI might be warranted.

Chloroformate derivatization for tracing the fate of Amino acids in cells and tissues by multiple stable isotope resolved metabolomics (mSIRM)

Amino acids have crucial roles in central metabolism, both anabolic and catabolic. To elucidate these roles, steady-state concentrations of amino acids alone are insufficient, as each amino acid participates in multiple pathways and functions in a complex network, which can also be compartmentalized. Stable Isotope-Resolved Metabolomics (SIRM) is an approach that uses atom-resolved tracking of metabolites through biochemical transformations in cells, tissues, or whole organisms. Using different elemental stable isotopes to label multiple metabolite precursors makes it possible to resolve simultaneously the utilization of these precursors in a single experiment. Conversely, a single precursor labeled with two (or more) different elemental isotopes can trace the allocation of e.g. C and N atoms through the network. Such dual-label experiments however challenge the resolution of conventional mass spectrometers, which must distinguish the neutron mass differences among different elemental isotopes. This requires ultrahigh resolution Fourier transform mass spectrometry (UHR-FTMS). When combined with direct infusion nano-electrospray ion source (nano-ESI), UHR-FTMS can provide rapid, global, and quantitative analysis of all possible mass isotopologues of metabolites. Unfortunately, very low mass polar metabolites such as amino acids can be difficult to analyze by current models of UHR-FTMS, plus the high salt content present in typical cell or tissue polar extracts may cause unacceptable ion suppression for sources such as nano-ESI. Here we describe a modified method of ethyl chloroformate (ECF) derivatization of amino acids to enable rapid quantitative analysis of stable isotope labeled amino acids using nano-ESI UHR-FTMS. This method showed excellent linearity with quantifiable limits in the low nanomolar range represented in microgram quantities of biological specimens, which results in extracts with total analyte abundances in the low to sub-femtomole range. We have applied this method to profile amino acids and their labeling patterns in ¹³C and ²H doubly labeled PC9 cell extracts, cancerous and non-cancerous tissue extracts from a lung cancer patient and their protein hydrolysates as well as plasma extracts from mice fed with a liquid diet containing ¹³C₆-glucose (Glc). The multi-element isotopologue distributions provided key insights into amino acid metabolism and intracellular pools in human lung cancer tissues in high detail. The ¹³C labeling of Asp and Glu revealed de novo synthesis of these amino acids from ¹³C₆-Glc via the Krebs cycle, specifically the elevated level of ¹³C₃-labeled Asp and Glu in cancerous versus non-cancerous lung tissues was consistent with enhanced pyruvate carboxylation. In addition, tracking the fate of double tracers, (¹³C₆-Glc + ²H₂-Gly or ¹³C₆-Glc + ²H₃-Ser) in PC9 cells clearly resolved pools of Ser and Gly synthesized de novo from ¹³C₆-Glc (¹³C₃-Ser and ¹³C₂-Gly) versus Ser and Gly derived from external sources (²H₃-Ser, ²H₂-Gly). Moreover the complex ²H labeling patterns of the latter were results of Ser and Gly exchange through active Ser-Gly one-carbon metabolic pathway in PC9 cells.

Long-term exercise in mice has sex-dependent benefits on body composition and metabolism during aging

Aging is associated with declining exercise and unhealthy changes in body composition. Exercise ameliorates certain adverse age‐related physiological changes and protects against many chronic diseases. Despite these benefits, willingness to exercise and physiological responses to exercise vary widely, and long‐term exercise and its benefits are difficult and costly to measure in humans. Furthermore, physiological effects of aging in humans are confounded with changes in lifestyle and environment. We used C57BL/6J mice to examine long‐term patterns of exercise during aging and its physiological effects in a well‐controlled environment. One‐year‐old male (n = 30) and female (n = 30) mice were divided into equal size cohorts and aged for an additional year. One cohort was given access to voluntary running wheels while another was denied exercise other than home cage movement. Body mass, composition, and metabolic traits were measured before, throughout, and after 1 year of treatment. Long‐term exercise significantly prevented gains in body mass and body fat, while preventing loss of lean mass. We observed sex‐dependent differences in body mass and composition trajectories during aging. Wheel running (distance, speed, duration) was greater in females than males and declined with age. We conclude that long‐term exercise may serve as a preventive measure against age‐related weight gain and body composition changes, and that mouse inbred strains can be used to characterize effects of long‐term exercise and factors (e.g. sex, age) modulating these effects. These findings will facilitate studies on relationships between exercise and health in aging populations, including genetic predisposition and genotype‐by‐environment interactions.

Branched-Chain Amino Acid Supplementation in Combination with Voluntary Running Improves Body Composition in Female C57BL/6 Mice

Exercise is an inexpensive intervention that may be used to reduce obesity and its consequences. In addition, many individuals who regularly exercise utilize dietary supplements to enhance their exercise routine and to accelerate fat loss or increase lean mass. Branched-chain amino acids (BCAAs) are a popular supplement and have been shown to produce a number of beneficial effects in rodent models and humans. Therefore, we hypothesized that BCAA supplementation would protect against high fat diet (HFD)-induced glucose intolerance and obesity in mice with and without access to exercise. We subjected 80 female C57BL/6 mice to a paradigm of HFD feeding, exercise in the form of voluntary wheel running, and BCAA supplementation in the drinking water for 16 weeks (n = 10 per group). Body weight was monitored weekly, while food and water consumption were recorded twice weekly. During the 5th, 10th, and 15th weeks of treatment, glucose tolerance and body composition were analyzed. Exercise significantly improved glucose tolerance in both control-fed and HFD-fed mice. BCAA supplementation, however, did not significantly alter glucose tolerance in any treatment group. While BCAA supplements did not improve lean to fat mass ratio in sedentary mice, it significantly augmented the effects of exercise on this parameter.

Metabolomic analysis of long-term spontaneous exercise in mice suggests increased lipolysis and altered glucose metabolism when animals are at rest

Exercise has been associated with several beneficial effects and is one of the major modulators of metabolism. The working muscle produces and releases substances during exercise that mediate the adaptation of the muscle but also improve the metabolic flexibility of the complete organism, leading to adjustable substrate utilization. Metabolomic studies on physical exercise are scarce and most of them have been focused on the effects of intense exercise in professional sportsmen. The aim of our study was to determine plasma metabolomic adaptations in mice after a long-term spontaneous exercise intervention study (18 mo). The metabolic changes induced by long-term spontaneous exercise were sufficient to achieve complete discrimination between groups in the principal component analysis scores plot. We identified plasma indicators of an increase in lipolysis (elevated unsaturated fatty acids and glycerol), a decrease in glucose and insulin plasma levels and in heart glucose consumption (by PET), and altered glucose metabolism (decreased alanine and lactate) in the wheel running group. Collectively these data are compatible with an increase in skeletal muscle insulin sensitivity in the active mice. We also found an increase in amino acids involved in catecholamine synthesis (tyrosine and phenylalanine), in the skeletal muscle pool of creatine phosphate and taurine, and changes in phospholipid metabolism (phosphocholine and choline in lipids) between the sedentary and the active mice. In conclusion, long-term spontaneous wheel running induces significant plasma and tissue (heart) metabolic responses that remain even when the animal is at rest.

Voluntary exercise under a food restriction condition decreases blood branched-chain amino acid levels, in addition to improvement of glucose and lipid metabolism, in db mice, animal model of type 2 diabetes

OBJECTIVES

Exercise is effective for preventing the onset and development of type 2 diabetes mellitus (T2DM) in human cases; however, the effect of exercise on the pathophysiology using animal models of T2DM has not been fully evaluated.

METHODS

We applied voluntary exercise under pair-fed (P) conditions in db mice, an animal model of T2DM. Exercising (Ex) and sedentary (Se) mice were placed in a cage, equipped with a free or locked running wheel, for 4 weeks, respectively. The amount of food consumed by ad libitum-fed wild-type mice under the Se condition (ad-WT) was supplied to all mice, except ad libitum db mice (ad-db). Blood parameters and expression of the genes involved in nutrient metabolism were analyzed.

RESULTS

PEx-db (pair-fed and exercising) mice showed significantly lower HbA1c, body weight and liver weight than PSe-db and ad-db mice. Decreased hepatic triglycerides in PEx-db mice corresponded to a lower expression of lipogenic enzyme genes in the liver. Moreover, PEx-db mice showed significantly lower plasma branched-chain amino acids (BCAA), arginine, proline, and tyrosine, in addition to increased skeletal muscle (SM) weight, than PSe-db and ad-db mice, in spite of little influence on the expression of the BCAA transaminase gene, in SM and WAT.

CONCLUSION

We found that exercise under a food restriction condition decreases several amino acids, including BCAA, and may improve insulin sensitivity more than mere food restriction. We propose that the decreased concentration of blood amino acids may be a valuable marker evaluating the effects of exercise on diabetic conditions.

A novel long term short interval physical activity regime improves body composition in mice

BACKGROUND

Exercise training (ET) and physical activity (PA) offer obvious health benefits in regular participants. In pre-clinical animal models, treadmills and running wheels are the models of choice for intervention studies using ET and PA. However, the frequency and duration necessary for positive effects on health are not completely understood. We investigated the impact of short duration voluntary wheel running on body composition in FVB × C57BL/6 F1 hybrid mice over 22 weeks. Mice were randomized and given access to voluntary wheel running (N = 6) or locked wheels (N = 5) for 1 hour per night during the dark cycle, 5 days per week.

FINDING

Average weekly running distance was generally cyclic in nature over the 22 weeks but did not change significantly from week to week, except for a difference between week 3 and week 9 (P = 0.05). Daily running distances ranged from 0.78 km to 1.45 km. Compared with non-runners, runners demonstrated significantly lower relative fat mass (9.98 ± 0.56% vs. 14.91 ± 1.47%, P = 0.0067) and significantly higher relative lean mass (79.18 ± 0.65% vs. 75.41 ± 1.28%, P = 0.019). No differences were observed with respect to glucose metabolism.

CONCLUSION

Voluntary wheel running for one hour a day five days a week over a five month period improved body composition in young adult mice. This repetitive short interval exercise regime should be a useful model to investigate the effects of structured moderate intensity physical activity on physiological performance and chronic disease conditions in mice.