Skeletal muscle adaptation in response to exercise (Ⅰ)

INTRODUCTIONSkeletalmusclesofadultmammalianspecies,includinghumans,arethesourceofpowerforlocomotionandotherdailyactivitiesessentialforsurvival.Lossofskeletalmusclecontractilefunctionisamajorcauseoffalling,morbidityandmortality,especiallyinelderlypopulations[1].Moreimportantly,skeletalmusclescollectivelyinfluencetotalbodymetabolismofglucose,fatandprotein,abnormalitiesofwhichareasso鄄ciatedwithavarietyofcommondiseases[2-3].Physicalinactivi鄄ty,adecreaseduseofthemusculoskeletalsystem,isassoc…     

Skeletal muscle adaptation in response to exercise（I）

Skeletal muscles of adult mammalian species, includinghumans,are the source of power for locomotion and otherdaily activities essential for survival. Loss of skeletal musclecontractile function is a major cause of falling,morbidity andmortality,especially in elderly populations.More importantly,skeletal muscles collectively influence total body metabolism     

Serological response to tick-borne encephalitis (TBE) vaccination in the elderly – results from an observational study

Background: In the elderly, the incidence of tick-borne encephalitis (TBE) is higher than in younger individuals. At the same time, the responsiveness of the elderly to vaccination may be decreased. Product information for TBE vaccines therefore recommends determining antibody response after two of the three doses required for primary immunization in persons over 60. Objective: To determine the proportion of persons aged 60 years or older with insufficient antibody response after administration of two doses of TBE vaccine. Methods: A retrospective analysis of TBE-specific antibody levels as determined by Immunozym^® ELISA in serum samples of 185 vaccinees > 60 years of age after the first two of the three vaccinations required for primary immunisation. Patients received either FSME-IMMUN Adult or Encepur^® Adults at one vaccination centre in the Czech Republic. In a subset of 80 vaccinees, two additional ELISAs and a neutralization test (NT) were performed. Results: Overall, 33 of the 185 individuals (18%) included in the Immunozym analysis had antibody concentrations below putative protective levels after two doses. Geometric mean concentrations and seropositivity rates were higher in individuals vaccinated with FSME-IMMUN than in those vaccinated with Encepur^®. While the differences in mean antibody levels and/or seropositivity rates in ELISAs for the Neudörfl strain (used in FSME-IMMUN) were significant, no significant differences were obtained for Enzygnost, which uses the Karlsruhe strain (used in Encepur). Conclusions: After two doses of TBE vaccine, one in five persons aged 60 years or older may be without protective antibodies, confirming the importance of testing the antibody response after the second vaccination and administering an additional dose in the event of insufficient response.     

The astaxanthin-induced improvement in lipid metabolism during exercise is mediated by a PGC-1α increase in skeletal muscle

Astaxanthin, a xanthophyll carotenoid, accelerates lipid utilization during aerobic exercise, although the underlying mechanism is unclear. The present study investigated the effect of astaxanthin intake on lipid metabolism associated with peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) in mice. Mice were divided into 4 groups: sedentary, sedentary and astaxanthin-treated, exercised, and exercised and astaxanthin-treated. After 2 weeks of treatment, the exercise groups performed treadmill running at 25 m/min for 30 min. Immediately after running, intermuscular pH was measured in hind limb muscles, and blood was collected for measurements. Proteins were extracted from the muscle samples and PGC-1α and its downstream proteins were measured by western blotting. Levels of plasma fatty acids were significantly decreased after exercise in the astaxanthin-fed mice compared with those fed a normal diet. Intermuscular pH was significantly decreased by exercise, and this decrease was inhibited by intake of astaxanthin. Levels of PGC-1α and its downstream proteins were significantly elevated in astaxanthin-fed mice compared with mice fed a normal diet. Astaxanthin intake resulted in a PGC-1α elevation in skeletal muscle, which can lead to acceleration of lipid utilization through activation of mitochondrial aerobic metabolism.     

Osteoblast growth and bone-healing response to three-dimensional poly(ε-caprolactone fumarate) scaffolds

Poly(ε-caprolactone fumarate) (PCLF) scaffold formulations were assessed as a delivery system for recombinant human bone morphogenetic protein (rhBMP-2) for bone tissue engineering. The formulations included PCLF with combinations of poly(vinyl alcohol) (PVA) and hydroxyapatite (HA). The assessments included in vitro and in vivo assays. In vitro assays validated cell attachment using a pre-osteoblast cell line (MC3T3-E1). Additionally, in vitro release profiles of rhBMP-2 from PCLF scaffolds were determined up to 21 days. The data suggested that PCLF incorporated with PVA and HA accelerated rhBMP-2 release and that the released protein was bioactive. For the in vivo study, a critical-sized defect (CSD) model in rabbit calvaria was used to test PCLF scaffolds. At 6 weeks post-implantation, significantly more bone formation was measured in PCLF scaffolds containing rhBMP-2 than in scaffolds without rhBMP-2. In conclusion, we demonstrated that PCLF delivered biologically active rhBMP-2, promoted bone healing in a CSD and has potential as a bone tissue engineering scaffold.     

Does aerobic exercise affect the hypothalamic-pituitary-adrenal hormonal response in patients with fibromyalgia syndrome?

[Purpose] The hypothalamic-pituitary-adrenal (HPA) axis in the etiopathogenesis of fibromyalgia is not clear. This study aimed to analyze the effects of a 6-week aerobic exercise program on the HPA axis in patients with fibromyalgia and to investigate the effects of this program on the disease symptoms, patients’ fitness, disability, and quality of life. [Subjects and Methods] Fifty fibromyalgia patients were randomized to Group 1 (stretching and flexibility exercises at home for 6 weeks) and Group 2 (aerobic exercise three times a week and the same at-home exercises as Group 1 for 6 weeks). Serum levels of cortisol, adrenocorticotropic hormone, insulin-like growth factor-1, and growth hormone were analyzed at baseline and at the end of, and 1 hr after an exercise stress test. [Results] Group 2 showed better improvement in morning stiffness duration and pain. Growth hormone levels significantly increased after intervention and cortisol levels significantly decreased at time-time interaction in both groups. No significant differences in adrenocorticotropic hormone and insulin-like growth factor-1 were found. [Conclusion] The results of this study seem to support the hypothesis that there is a dysregulation of the HPA axis in patients with FM, and that a six-week exercise program can influence symptoms and affect the HPA axis hormones.Key words: Fibromyalgia, Aerobic exercise, Hypothalamic-pituitary-adrenal axis     

Test–retest reliability of skeletal muscle oxygenation measurements during submaximal cycling exercise in patients with chronic heart failure

The potential purpose of near-infrared spectroscopy (NIRS) as a clinical application in patients with chronic heart failure (CHF) is the identification of limitations in O₂ delivery or utilization during exercise. The objective of this study was to evaluate absolute and relative test–retest reliability of skeletal muscle oxygenation measurements in patients with CHF. Thirty patients with systolic heart failure (left ventricular ejection fraction 31 ± 8%) performed 6-min constant-load cycling tests at 80% of the anaerobic threshold (AT) with tissue saturation index (TSI) measurement at the vastus lateralis. Tests were repeated after 10 ± 5 days to evaluate reliability. Absolute reliability was assessed with limits of agreement (LoA, expressed as bias ± random error) and coefficients of variation (CV) for absolute values (LoA range: 0·4 ± 6·2% to 0·6 ± 7·9%; CV range: 4·7–7·1%), amplitudes (LoA range −0·5 ± 5·8% to −0·7 ± 6·8%; CV range: 26·2–42·1%), onset and recovery kinetics (mean response times; LoA 0·4 ± 9·5 s, CV 23·5% and LoA −5·8 ± 50·8 s, CV 67·4% respectively) and overshoot characteristics (CV range 45·7–208·6%). Relative reliability was assessed with intraclass correlation coefficients for absolute values (range 0·74–0·90), amplitudes (range 0·85–0·92), onset and recovery kinetics (0·53 and 0·51, respectively) and overshoot characteristics (range 0·17–0·74). In conclusion, absolute reliability of absolute values and onset kinetics seems acceptable for serial within-subject comparison, and as such, for evaluation of treatment effects. Absolute reliability of amplitudes and recovery kinetics is considered unsatisfactory. Relative reliability of absolute values and amplitudes is sufficient for purposes of physiological distinction between patients with CHF. Despite lower relative reliability, kinetics may still be useful for clinical application.     

Can childhood trauma predict response to topiramate in borderline personality disorder?

We report on a woman with borderline personality disorder and a history of childhood trauma that showed significant clinical response with low dosage of topiramate. We propose that topiramate changed some of the main features of this disorder, such as catastrophic reaction to real or imaginary abandonment or rejection, improving adaptive functioning. We hypothesize that topiramate might facilitate memory extinction, therefore decreasing emotional and behavioural reactivity.     

C-reactive protein induced inflammatory response in pulmonary artery smooth muscle cell by nuclear factor-κB pathway

Objective To examine the impact of C-reactive protein (CRP) on the expression of interleukin-6 (IL-6), inflammatory cytokine, in cultured human pulmonary artery smooth muscle cells (hPASMCs) in order to find out the cause of pulmonary artery hypertension (PAH). Method The hPASMCs were cultured and stimulated by different concerntrations of CRP (5 - 200 μg/ml) for different lengths of time. The activity of nuclear factor-κB (NF-κB) was evaluated by electrophoretic gel mobility shift assay (EMSA). The expression of IL-6 mRNA and the level of IL-6 protein were measured by using real-time PCR and ELISA, respectively. Results CRP increased IL-6 production in hPASMCs in a dose-dependent manner. The increase in IL-6 at concerntration of 200 μg/mL in the CRP group was as high as 2.8times that in the control group. CRP also significantly induced the activation of NF-κB in hPASMCs. The effect of CRP on the inflammatory cytokine, IL-6, was inhibited by the specific FcγⅡa receptor antibody.Conclusions In vitro, CRP increases the production of IL-6 in hPASMCs mediated by FcγⅡa receptor and NF-κB translocation. These data offer important insights into the role of CRP in the pathogenesis of PAH.     

Implication of γδ T cells in the human immune response to cytomegalovirus

In normal individuals, gammadelta T cells account for less than 6% of total peripheral T lymphocytes and mainly express T-cell receptor (TCR) Vdelta2-Vgamma9 chains. We have previously observed a dramatic expansion of gammadelta T cells in the peripheral blood of renal allograft recipients only when they developed cytomegalovirus (CMV) infection. This increase was long lasting (more than 1 year), was associated with an activation of gammadelta T cells, and concerned only Vdelta1 or Vdelta3 T-cell subpopulations. Analysis of gammadelta TCR junctional diversity revealed that CMV infection in these patients was accompanied by (a) a marked restriction of CDR3 size distribution in Vdelta3 and, to a lesser extent, in Vdelta1 chains; and (b) a selective expansion of Vdelta1 cells bearing recurrent junctional amino acid motifs. These features are highly suggestive of an in vivo antigen-driven selection of gammadelta T-cell subsets during the course of CMV infection. Furthermore, Vdelta1 and Vdelta3 T cells from CMV-infected kidney recipients were able to proliferate in vitro in the presence of free CMV or CMV-infected fibroblast lysates but not uninfected or other herpes virus-infected fibroblast lysates. This in vitro expansion was inhibited by anti-gammadelta TCR mAb's. These findings suggest that a population of gammadelta T cells might play an important role in the immune response of immunosuppressed patients to CMV infection.