Gut Microflora and Health

Human gastrointestinal tract harbors a diverse population of microorganisms, the gut microbiata, the largest microbial community associated with human body, comprised of trillions of bacterial cells of over 1000 species. Although gut lumen is an extension of the external world for our organs and tissues, the interaction between human body and gut microbiata is highly mutual and reciprocal as if it is one of the internal organs. In animal experiments and human observational studies, gut microflora and its composition have been demonstrated to have significant roles in body fat accumulation, and consequently, insulin resistance and obesity. The metabolic activity of gut microbiata is suggested to contribute to the regulation of energy storage. Low grade inflammation possibly elicited through recognition of bacterial components by gut associated immune system is considered as another factor contributing to the development of obesity and atherosclerosis. Based on the observations of the contribution of gut microbiata to human health, practical approaches to modify or improve gut microbial composition has been a center of interest in the field of health promotion for decades. Modification of dietary habit, administration of pre- and probiotics as well as regular exercise are suggested to potentially modify gut microbial components. The biggest issue, however, is that we still don’t have an established or agreed method of characterizing composition of gut microorganisms, lacking the mechanistic link between the composition of microorganisms and the anticipated effect. This is largely due to its high diversity among species, human races and individuals. Recent advances in system biological approach, such as metabolomics and metagenomics may find a thread through the cosmic world of microbiome in our body

Contribution of lactobacillus casei to the recovery from chemically induced skeletal muscle damage under chronic stress

Background: Regeneration of damaged skeletal muscle requires sufficient supply of nutrients. Fully functional intestine and colon assure sufficient supply of nutrients. Gut commensal bacteria are known to support intestinal function. Previously lactobacillus treatment of elite athletes was shown to be effective in attenuating fatigue and impaired performance. We hypothesized that Lactobacillus casei (L.casei) administration may facilitate recovery of damaged skeletal muscle when the gut function is suppressed under chronic stress in which muscle regeneration is compromised. Objective: To investigate contribution of L.casei under chronic stress to the recovery of damaged skeletal muscle in young and older adult mice. Methods: L.casei was given orally at a dose of 10-8 /day for 7days to 10 weeks old (young) and 45-55 weeks old (older adult) male C57BL/6J mice. Vehicle control mice received an equivalent volume of water for 7 days. On the eighth day, cardiotoxin (CTX) was injected to gatrocnemius muscle to induce muscle damage. Both groups were assigned 2 hours repeated-restraint stress everyday (chronic stress). On days 3, 5, 7, 10, 14 and 20 after CTX injection, mice were sacrificed. Excised gastrocnemius muscle was subjected to weight measurement and immunohistochemical analyses. Results: There were significant differences in both the recovery of muscle weight and the regeneration process of gastrocnemius muscle examined immunohistochemically between control and L.casei treated young and older adult groups. Especially, the expression of developmental MHC (dMHC), a marker of premature regeneration, was positive up to 3 days in older adult groups. The delay in the recovery of muscle weight was obvious in older adult mice regardless of the treatment. However, while the expression of dMHC was prolonged up to day 7 in the vehicle control, dMHC expression was notable only up to day 3 or day 5 in the L.casei treated. Therefore, in older adult mice L.casei treatment under chronic stress may have facilitated the maturation process of regenerating skeletal muscle. Conclusion: Our results suggests that L.casei favor under chronic stress favors the recovery of skeletal muscle from muscle damage. The maintenance of gut function by L. casei treatment may have facilitated the maturation process of regenerating skeletal muscle

Can Compression Garments Reduce the Deleterious Effects of Physical Exercise on Muscle Strength?:A Systematic Review and Meta-Analyses

Background: The use of compression garments (CGs) during or after training and competition has gained popularity in the last few decades. However, the data concerning CGs’ beneficial effects on muscle strength-related outcomes after physical exercise remain inconclusive. Objective: The aim was to determine whether wearing CGs during or after physical exercise would facilitate the recovery of muscle strength-related outcomes. Methods: A systematic literature search was conducted across five databases (PubMed, SPORTDiscus, Web of Science, Scopus, and EBSCOhost). Data from 19 randomized controlled trials (RCTs) including 350 healthy participants were extracted and meta-analytically computed. Weighted between-study standardized mean differences (SMDs) with respect to their standard errors (SEs) were aggregated and corrected for sample size to compute overall SMDs. The type of physical exercise, the body area and timing of CG application, and the time interval between the end of the exercise and subsequent testing were assessed. Results: CGs produced no strength-sparing effects (SMD [95% confidence interval]) at the following time points (t) after physical exercise: immediately ≤ t < 24 h: − 0.02 (− 0.22 to 0.19), p = 0.87; 24 ≤ t < 48 h: − 0.00 (− 0.22 to 0.21), p = 0.98; 48 ≤ t < 72 h: − 0.03 (− 0.43 to 0.37), p = 0.87; 72 ≤ t < 96 h: 0.14 (− 0.21 to 0.49), p = 0.43; 96 h ≤ t: 0.26 (− 0.33 to 0.85), p = 0.38. The body area where the CG was applied had no strength-sparing effects. CGs revealed weak strength-sparing effects after plyometric exercise. Conclusion: Meta-analytical evidence suggests that wearing a CG during or after training does not seem to facilitate the recovery of muscle strength following physical exercise. Practitioners, athletes, coaches, and trainers should reconsider the use of CG as a tool to reduce the effects of physical exercise on muscle strength. Trial Registration Number: PROSPERO CRD42021246753

Can Compression Garments Reduce the Deleterious Effects of Physical Exercise on Muscle Strength? A Systematic Review and Meta-Analyses

Background: The use of compression garments (CGs) during or after training and competition has gained popularity in the last few decades. However, the data concerning CGs’ beneficial effects on muscle strength-related outcomes after physical exercise remain inconclusive. Objective: To determine if wearing CG during or after physical exercise would facilitate the recovery of muscle strength-related outcomes. Methods: A systematic literature search was conducted across 5 databases (PubMed, SportDiscus, Web of Science, Scopus, and EBSCOhost). Data from 19 RCTs including 350 healthy participants were extracted and meta-analytically computed. Weighted between-study standardized mean differences (SMDs) with respect to their standard errors (SE) were aggregated and corrected for sample size to compute overall SMDs. The type of physical exercise, the body area and timing of CG application, and the time interval between the end of the exercise and subsequent testing were assessed. Results: Compression garments produced no strength-sparing effects: a) immediately ≤ t < 24h: SMD = -0.02 [-0.22 to 0.19], p = 0.87; b) 24 ≤ t < 48h: SMD = -0.00 [-0.22 to 0.21], p = 0.98; c) 48 ≤ t < 72h: SMD = -0.03 [-0.43 to 0.37], p = 0.87; d) 72 ≤ t < 96h: SMD = 0.14 [-0.21 to 0.49], p = 0.43; e) 96h ≤ t: SMD = 0.26 [-0.33 to 0.85], p = 0.38 after physical exercise. The body area where the CG was applied had no strength-sparing effects. Compression garments revealed weak strength-sparing effects after plyometric exercise. Conclusion: Meta-analytical evidence suggests that wearing a CG during or after training does not seem to facilitate the recovery of muscle strength following physical exercise. Practitioners, athletes, coaches, and trainers, should reconsider the use of CG as a tool to reduce the effects of physical exercise on muscle strength

Age-specific modifications in healthy adults' knee joint position sense

Aim: Right-handed young adults perform target-matching tasks more accurately with the non-dominant (ND) compared to the dominant (D) limb, but it is unclear if age affects this disparity. We determined if age affects target-matching asymmetry in right-side dominant healthy adults. Method: Young (n = 12, age: 23.6 y, 6 females) and older (n = 12; age: 75.1 y, 7 females) adults performed a passive joint position-matching task with the D and ND leg in a randomized order. Result: Age affected absolute, constant, and variable knee JPS errors but, contrary to expectations, it did not affect target-matching asymmetries between the D and ND knees. However, older participants tended to underestimate while young subjects overestimated the target angles. Moreover, older as compared to young subjects performed the target-matching task with higher variability. Conclusion: Altogether, age seems to affect passive knee target-matching behaviour in right-side dominant healthy adults. The present data indicate that healthy aging produces age-specific modifications in passive joint position sense.</p

A below-knee compression garment reduces fatigue-induced strength loss but not knee joint position sense errors

Purpose We examined the possibility that wearing a below-knee compression garment (CG) reduces fatigue-induced strength loss and joint position sense (JPS) errors in healthy adults. Methods Subjects (n = 24, age = 25.5 +/- 4 years) were allocated to either one of the treatment groups that performed 100 maximal isokinetic eccentric contractions at 30 degrees(-1)with the right-dominant knee extensors: (1) with (EXPCG) or (2) without CG (EXP) or to (3) a control group (CONCG:CG, no exercise). Changes in JPS errors, and maximal voluntary isometric contraction (MVIC) torque were measured immediately post-, 24 h post-, and 1 week post-intervention in each leg. All testing was done without the CG. Results CG afforded no protection against JPS errors. Mixed analysis of variance (ANOVA) revealed that absolute JPS errors increased post-intervention in EXPCG and EXP not only in the right-exercised (52%,p = 0.013; 57%,p = 0.007, respectively) but also in the left non-exercised (55%,p = 0.001; 58%,p = 0.040, respectively) leg. Subjects tended to underestimate the target position more in the flexed vs. extended knee positions (75-61 degrees: - 4.6 +/- 3.6 degrees, 60-50 degrees: - 4.2 +/- 4.3 degrees, 50-25 degrees: - 2.9 +/- 4.2 degrees), irrespective of group and time. Moreover, MVIC decreased in EXP but not in EXPCG and CONCG at immediately post-intervention (p = 0.026,d = 0.52) and 24 h post-intervention (p = 0.013,d = 0.45) compared to baseline. Conclusion Altogether, a below-knee CG reduced fatigue-induced strength loss at 80 degrees knee joint position but not JPS errors in healthy younger adults

Cost-effectiveness Analysis of CO2 Reduction in the Automobile Sector

Various problems relating to energy and the environment clearly exist, such as global warming and a steep rise in the price fossil fuels, and resources. These problems should be addressed in the medium term or long run. As for the abatement of greenhouse gas emission, active discussions have been held on the stage of world politics to achieve the long-term goal. Although various approaches have been proposed by several research institutions and countries, sufficient studies have not yet been conducted on the roles of individual countries and sectors. Specifically, in the automotive transportation sector wherein oil demand and CO2 emissions are estimated to rise in the future with the marked progress of motorization in developing countries, it is increasingly important to study these subjects. We focused on the automotive transportation sector and studied the CO2 abatement potential and its cost performance in this sector. This article reports the results of the study.energy and the environment, Climate change, automotive transportation

An inverted J-shaped association of serum uric acid with muscle strength among Japanese adult men: a cross-sectional study

BACKGROUND: Uric acid (UA) may protect muscle function from oxidative damage due to reactive oxygen species through its powerful antioxidant capacity. However, several studies have demonstrated that hyperuricemia is closely related to systemic inflammation and has oxidant properties effects, both of which may increase the risk of muscle strength loss. The purpose of this study was to examine the association of serum UA concentration with grip strength and leg extension power in adult men. METHODS: This study is a cross-sectional survey in which 630 Japanese male employees aged 30 years and older participated. Five hundred and eighty-six subjects participated in the measurement of grip strength, and 355 subjects participated in the measurement of leg extension power. Blood samples were obtained for serum UA analysis. RESULTS: After adjustment for potential confounders, grip strength differed significantly between participants with and those without hyperuricemia (geometric mean and 95% confidence interval [CI]: 40.3 [39.2–41.3] kg vs. 41.9 [41.3–42.5] kg; P = 0.01). In addition, serum UA levels (quartiles) showed an inverted J-shaped curve with grip strength (mean and 95% CI: Q1, 41.6 [40.6–42.6] kg; Q2, 42.2 [41.2–43.2] kg; Q3, 41.8 [40.8–42.8] kg; Q4, 40.4 [39.3–41.4] kg; P for quadratic trend = 0.05). The results in the leg extension power group were similar to those observed in the grip strength group. CONCLUSION: This population-based cross-sectional study shows for the first time that hyperuricemia is associated with poor muscle strength. Moreover, the results indicate an inverted J-shaped association between serum UA quartiles and muscle strength