Key points
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Contradictory findings have been reported concerning the function of irisin and its precursor gene, skeletal muscle FNDC5, in energy homeostasis and metabolic health, and the associated ...regulatory role of exercise and PGC‐1α.
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We analysed the effects of different short‐ and long‐term exercise regimens on muscle FNDC5 and PGC‐1α, and serum irisin, and studied the associations of irisin and FNDC5 with health parameters.
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FNDC5 and serum irisin did not change after acute aerobic, long‐term endurance training or endurance training combined with resistance exercise (RE) training, or associate with metabolic disturbances. A single RE bout increased FNDC5 mRNA in young, but not older men (27 vs. 62 years). Changes in PGC‐1α or serum irisin were not consistently accompanied by changes in FNDC5.
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Our data suggest that the effects of exercise on FNDC5 and irisin are not consistent, and that their role in health is questionable. Moreover, the regulatory mechanisms should be studied further.
Recently, contradictory findings have been reported concerning the function of irisin and its precursor gene, skeletal muscle FNDC5, in energy homeostasis, and the associated regulatory role of exercise and PGC‐1α. We therefore evaluated whether muscle FNDC5 mRNA and serum irisin are exercise responsive and whether PGC‐1α expression is associated with FNDC5 expression. The male subjects in the study performed single exercises: (1) 1 h low‐intensity aerobic exercise (AE) (middle‐aged, n= 17), (2) a heavy‐intensity resistance exercise (RE) bout (young n= 10, older n= 11) (27 vs. 62 years), (3) long‐term 21 weeks endurance exercise (EE) training alone (twice a week, middle‐aged, n= 9), or (4) combined EE and RE training (both twice a week, middle‐aged, n= 9). Skeletal muscle mRNA expression was analysed by quantitative PCR and serum irisin by ELISA. No significant changes were observed in skeletal muscle PGC‐1α, FNDC5 and serum irisin after AE, EE training or combined EE + RE training. However, a single RE bout increased PGC‐1α by 4‐fold in young and by 2‐fold in older men, while FNDC5 mRNA only increased in young men post‐RE, by 1.4‐fold. Changes in PGC‐1α or serum irisin were not consistently accompanied by changes in FNDC5. In conclusion, for the most part, neither longer‐term nor single exercise markedly increases skeletal muscle FNDC5 expression or serum irisin. Therefore their changes in response to exercise are probably random and not consistent excluding the confirmation of any definitive link between exercise and FNDC5 expression and irisin release in humans. Moreover, irisin and FNDC5 were not associated with glucose tolerance and being overweight, or with metabolic disturbances, respectively. Finally, factor(s) other than PGC‐1α and transcription may regulate FNDC5 expression.
Fatty liver is a major cause of obesity-related morbidity and mortality. The aim of this study was to identify early metabolic alterations associated with liver fat accumulation in 50- to 55-year-old ...men (n = 49) and women (n = 52) with and without NAFLD.
Hepatic fat content was measured using proton magnetic resonance spectroscopy (1H MRS). Serum samples were analyzed using a nuclear magnetic resonance (NMR) metabolomics platform. Global gene expression profiles of adipose tissues and skeletal muscle were analyzed using Affymetrix microarrays and quantitative PCR. Muscle protein expression was analyzed by Western blot.
Increased branched-chain amino acid (BCAA), aromatic amino acid (AAA) and orosomucoid were associated with liver fat accumulation already in its early stage, independent of sex, obesity or insulin resistance (p<0.05 for all). Significant down-regulation of BCAA catabolism and fatty acid and energy metabolism was observed in the adipose tissue of the NAFLD group (p<0.001for all), whereas no aberrant gene expression in the skeletal muscle was found. Reduced BCAA catabolic activity was inversely associated with serum BCAA and liver fat content (p<0.05 for all).
Liver fat accumulation, already in its early stage, is associated with increased serum branched-chain and aromatic amino acids. The observed associations of decreased BCAA catabolism activity, mitochondrial energy metabolism and serum BCAA concentration with liver fat content suggest that adipose tissue dysfunction may have a key role in the systemic nature of NAFLD pathogenesis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objective
To study whether normal‐weight obesity in childhood is associated with increased cardiometabolic risk in early adulthood.
Methods
This study assessed data for 236 girls followed from ...prepuberty to early adulthood. Growth chart data were obtained from birth to 18 years. Body composition was assessed by dual‐energy x‐ray absorptiometry and cardiometabolic risk by calculating continuous clustered risk score (at ages 11, 14, and 18). The association of body weight status with cardiometabolic risk from childhood to early adulthood was examined.
Results
Subjects with normal‐weight obesity were virtually indistinguishable from their normal‐weight lean peers in terms of relative body weight and BMI but had significantly higher fat mass (7.1‐7.3 kg) and cardiometabolic risk already in childhood, and this difference persisted into early adulthood (P < 0.001 for all).
Conclusions
Children and adolescents with normal body weight and high body fat percentage may be at increased risk for cardiometabolic morbidity in adulthood. Body fatness may be of utility in clinical practice to effectively identify children and adolescents at risk and to permit recommendation of lifestyle changes that could translate to lower risks of cardiovascular diseases in the future.
Executive functions underlie self-regulation and are thus important for physical activity and adaptation to new situations. The aim was to investigate, if yearlong physical and cognitive training ...(PTCT) had greater effects on physical activity among older adults than physical training (PT) alone, and if executive functions predicted physical activity at baseline, after six (6m) and twelve months (12m) of the interventions, one-year post-intervention follow-up and an extended follow-up during COVID-19 lockdown.
Data from a single-blinded, parallel-group randomized controlled trial (PASSWORD-study, ISRCTN52388040) were utilized. Participants were 70-85 years old community-dwelling men and women from Jyväskylä, Finland. PT (n = 159) included supervised resistance, walking and balance training, home-exercises and self-administered moderate activity. PTCT (n = 155) included PT and cognitive training targeting executive functions on a computer program. Physical activity was assessed with a one-item, seven-scale question. Executive functions were assessed with color-word Stroop, Trail Making Test (TMT) B-A and Letter Fluency. Changes in physical activity were modeled with multinomial logistic models and the impact of executive functions on physical activity with latent change score models.
No significant group-by-time interaction was observed for physical activity (p>0.1). The subjects were likely to select an activity category higher than baseline throughout the study (pooled data: B = 0.720-1.614, p<0.001-0.046). Higher baseline Stroop predicted higher physical activity through all subsequent time-points (pooled data: B = 0.011-0.013, p = 0.015-0.030). Higher baseline TMT B-A predicted higher physical activity at 6m (pooled data: B = 0.007, p = 0.006) and during COVID-19 (B = 0.005, p = 0.030). In the PT group, higher baseline Letter Fluency predicted higher physical activity at 12m (B = -0.028, p = 0.030) and follow-up (B = -0.042, p = 0.002).
Cognitive training did not have additive effects over physical training alone on physical activity, but multicomponent training and higher executive function at baseline may support adaptation to and maintenance of a physically active lifestyle among older adults.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
1 Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland; 2 Department of Clinical Neurophysiology, University of Uppsala, Uppsala, Sweden; 3 Department of Biology of Physical ...Activity, University of Jyväskylä; 4 The Finnish Centre for Interdisciplinary Gerontology; 5 KIHU Research Institute for Olympic Sports, Jyväskylä, Finland
Submitted 10 March 2006
; accepted in final form 9 May 2006
Biopsy samples were taken from the vastus lateralis of 18- to 84-yr-old male sprinters ( n = 91). Fiber-type distribution, cross-sectional area, and myosin heavy chain (MHC) isoform content were identified using ATPase histochemistry and SDS-PAGE. Specific tension and maximum shortening velocity ( V o ) were determined in 144 single skinned fibers from younger (1833 yr, n = 8) and older (5377 yr, n = 9) runners. Force-time characteristics of the knee extensors were determined by using isometric contraction. The cross-sectional area of type I fibers was unchanged with age, whereas that of type II fibers was reduced ( P < 0.001). With age there was an increased MHC I ( P < 0.01) and reduced MHC IIx isoform content ( P < 0.05) but no differences in MHC IIa. Specific tension of type I and IIa MHC fibers did not differ between younger and older subjects. V o of fibers expressing type I MHC was lower ( P < 0.05) in older than in younger subjects, but there was no difference in V o of type IIa MHC fibers. An aging-related decline of maximal isometric force ( P < 0.001) and normalized rate of force development ( P < 0.05) of knee extensors was observed. Normalized rate of force development was positively associated with MHC II ( P < 0.05). The sprint-trained athletes experienced the typical aging-related reduction in the size of fast fibers, a shift toward a slower MHC isoform profile, and a lower V o of type I MHC fibers, which played a role in the decline in explosive force production. However, the muscle characteristics were preserved at a high level in the oldest runners, underlining the favorable impact of sprint exercise on aging muscle.
exercise; myosin heavy chain; single-fiber contractile properties; muscle strength
Address for reprint requests and other correspondence: H. Suominen, Dept. of Health Sciences, Univ. of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland (e-mail: harri.suominen{at}sport.jyu.fi )
BACKGROUND: Little is known about the relative effectiveness of calcium supplementation from food or pills with or without vitamin D supplementation for bone mass accrual during the rapid growth ...period. OBJECTIVE: The purpose was to examine the effects of both food-based and pill supplements of calcium and vitamin D on bone mass and body composition in girls aged 10-12 y. DESIGN: This placebo-controlled intervention trial randomly assigned 195 healthy girls at Tanner stage I-II, aged 10-12 y, with dietary calcium intakes <900 mg/d to 1 of 4 groups: calcium (1000 mg) + vitamin D₃ (200 IU), calcium (1000 mg), cheese (1000 mg calcium), and placebo. Primary outcomes were bone indexes of the hip, spine, and whole body by dual-energy X-ray absorptiometry and of the radius and tibia by peripheral quantitative computed tomography. RESULTS: With the use of intention-to-treat or efficacy analysis, calcium supplementation with cheese resulted in a higher percentage change in cortical thickness of the tibia than did placebo, calcium, or calcium + vitamin D treatment (P = 0.01, 0.038, and 0.004, respectively) and in higher whole-body bone mineral density than did placebo treatment (P = 0.044) when compliance was >50%. With the use of a hierarchical linear model with random effects to control for growth velocity, these differences disappeared. CONCLUSIONS: Increasing calcium intake by consuming cheese appears to be more beneficial for cortical bone mass accrual than the consumption of tablets containing a similar amount of calcium. Diverse patterns of growth velocity may mask the efficacy of supplementation in a short-term trial of children transiting through puberty.
Objective
This study aimed at establishing bacterial flagellin‐recognizing toll‐like receptor 5 (TLR5) as a novel link between gut microbiota composition, adipose tissue inflammation, and obesity.
...Methods
An adipose tissue microarray database was used to compare women having the highest (n = 4, H‐TLR) and lowest (n = 4, L‐TLR) expression levels of TLR5‐signaling pathway genes. Gut microbiota composition was profiled using flow cytometry and FISH. Standard laboratory techniques were used to determine anthropometric and clinical variables. In vivo results were verified using cultured human adipocytes.
Results
The H‐TLR group had higher flagellated Clostridium cluster XIV abundance and Firmicutes‐to‐Bacteroides ratio. H‐TLR subjects had obese phenotype characterized by greater waist circumference, fat %, and blood pressure (P < 0.05 for all). They also had higher leptin and lower adiponectin levels (P < 0.05 for both). Six hundred and sixty‐eight metabolism‐ and inflammation‐related adipose tissue genes were differentially expressed between the groups. In vitro studies confirmed that flagellin activated TLR5 inflammatory pathways, decreased insulin signaling, and increased glycerol secretion.
Conclusions
The in vivo findings suggest that flagellated Clostridium cluster XIV bacteria contribute to the development of obesity through distorted adipose tissue metabolism and inflammation. The in vitro studies in adipocytes show that the underlying mechanisms of the human findings may be due to flagellin‐activated TLR5 signaling.
STUDY DESIGN.A retrospective epidemiological study.
OBJECTIVE.To reveal incidence and epidemiological features of traumatic spinal injuries (TSI) in Northern Finland.
SUMMARY OF BACKGROUND DATA.In ...Finland the annual incidence of traumatic spine fractures requiring inpatient care has been found to be 27/100,000, while international incidences have varied across the range of 16–64/100,000. More specific epidemiological data from Finland is not available. Internationally, the most common mechanisms of injury are road traffic as well as low and high falls. Associated injuries occur in 30% to 55% of cases.
METHODS.The study sample included patients with traumatic spinal injury admitted to Oulu University Hospital (OYS) with injury between the January 1, 2007 and December 31, 2011. Patient information was collected from the hospital care register, including all inpatient and outpatient visits and surgical procedures. Traumatic spinal column and spinal cord injuries were identified using International Classification of Diseases 10th revision or Nordic Classification of Surgical Procedures codes and all patient records were manually reviewed.
RESULTS.Nine hundred seventy-one patients met the criteria for TSI. The mean annual incidence of hospitalized traumatic spinal injuries was 26/100,000 in the whole of Northern Finland and 35/100,000 in the OYS main responsibility area. The most frequent etiology of TSI was low falls, which accounted for 35.8% of the injuries, followed by road traffic and high falls. Lumbar spine was the most common site of the fracture. Spinal surgery was performed in 376 (38.7%) cases. Three hundred eight patients (31.7%) suffered from associated injuries, 101 (10.4%) had a spinal cord injury, and 71 (7.3%) a brain injury.
CONCLUSION.Low falls in elderly and road traffic injuries in younger age groups were the most common etiology of traumatic spinal injuries in Northern Finland and should be given more attention in primary prevention.Level of Evidence3
Summary
MiRNAs are fine‐tuning modifiers of skeletal muscle regulation, but knowledge of their hormonal control is lacking. We used a co‐twin case–control study design, that is, monozygotic ...postmenopausal twin pairs discordant for estrogen‐based hormone replacement therapy (HRT) to explore estrogen‐dependent skeletal muscle regulation via miRNAs. MiRNA profiles were determined from vastus lateralis muscle of nine healthy 54–62‐years‐old monozygotic female twin pairs discordant for HRT (median 7 years). MCF‐7 cells, human myoblast cultures and mouse muscle experiments were used to confirm estrogen's causal role on the expression of specific miRNAs, their target mRNAs and proteins and finally the activation of related signaling pathway. Of the 230 miRNAs expressed at detectable levels in muscle samples, qPCR confirmed significantly lower miR‐182, miR‐223 and miR‐142‐3p expressions in HRT using than in their nonusing co‐twins. Insulin/IGF‐1 signaling emerged one common pathway targeted by these miRNAs. IGF‐1R and FOXO3A mRNA and protein were more abundantly expressed in muscle samples of HRT users than nonusers. In vitro assays confirmed effective targeting of miR‐182 and miR‐223 on IGF‐1R and FOXO3A mRNA as well as a dose‐dependent miR‐182 and miR‐223 down‐regulations concomitantly with up‐regulation of FOXO3A and IGF‐1R expression. Novel finding is the postmenopausal HRT‐reduced miRs‐182, miR‐223 and miR‐142‐3p expression in female skeletal muscle. The observed miRNA‐mediated enhancement of the target genes' IGF‐1R and FOXO3A expression as well as the activation of insulin/IGF‐1 pathway signaling via phosphorylation of AKT and mTOR is an important mechanism for positive estrogen impact on skeletal muscle of postmenopausal women.
Background & Aims Recent evidence suggests that in animals gut microbiota composition (GMC) affects the onset and progression of hepatic fat accumulation. The aim of this study was to investigate in ...humans whether subjects with high hepatic fat content (HHFC) differ in their GMC from those with low hepatic fat content (LHFC), and whether these differences are associated with body composition, biomarkers and abdominal adipose tissue inflammation. Methods Hepatic fat content (HFC) was measured using proton magnetic resonance spectroscopy (1 H MRS). Fecal GMC was profiled by 16S rRNA fluorescence in situ hybridization and flow cytometry. Adipose tissue gene expression was analyzed using Affymetrix microarrays and quantitative PCR. Results The HHFC group had unfavorable GMC described by lower amount of Faecalibacterium prausnitzii (FPrau) ( p <0.05) and relatively higher Enterobacteria than the LHFC group. Metabolically dysbiotic GMC associated with HOMA-IR and triglycerides ( p <0.05 for both). Several inflammation-related adipose tissue genes were differentially expressed and correlated with HFC ( p <0.05). In addition, the expression of certain genes correlated with GMC dysbiosis, i.e., low FPrau-to-Bacteroides ratio. Conclusions HHFC subjects differ unfavorably in their GMC from LHFC subjects. Adipose tissue inflammation may be an important link between GMC, metabolic disturbances, and hepatic fat accumulation.
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