Ulla Ramer Mikkelsen

Local NSAID infusion inhibits satellite cell proliferation in human skeletal muscle after eccentric exercise

Despite the widespread consumption of nonsteroidal anti-inflammatory drugs (NSAIDs), the influence of these drugs on muscle satellite cells is not fully understood. The aim of the present study was to investigate the effect of a local NSAID infusion on satellite cells after unaccustomed eccentric exercise in vivo in human skeletal muscle. Eight young healthy males performed 200 maximal eccentric contractions with each leg. An NSAID was infused via a microdialysis catheter into the vastus lateralis muscle of one leg (NSAID leg) before, during, and for 4.5 h after exercise, with the other leg working as a control (unblocked leg). Muscle biopsies were collected before and 8 days after exercise. Changes in satellite cells and inflammatory cell numbers were investigated by immunohistochemistry. Satellite cells were identified using antibodies against neural cell adhesion molecule and Pax7. The number of Pax7(+) cells per myofiber was increased by 96% on day 8 after exercise in the unblocked leg (0.14 +/- 0.04, mean +/- SE) compared with the prevalue (0.07 +/- 0.02, P < 0.05), whereas the number of Pax7(+) cells was unchanged in the leg muscles exposed to the NSAID (0.07 +/- 0.01). The number of inflammatory cells (CD68(+) or CD16(+) cells) was not significantly increased in either of the legs 8 days after exercise and was unaffected by the NSAID. The main finding in the present study was that the NSAID infusion for 7.5 h during the exercise day suppressed the exercise-induced increase in the number of satellite cells 8 days after exercise. These results suggest that NSAIDs negatively affect satellite cell activity after unaccustomed eccentric exercise.

Exercise increases interleukin-10 levels both intraarticularly and peri-synovially in patients with knee osteoarthritis: a randomized controlled trial

IntroductionThe microdialysis method was applied to the human knee joint with osteoarthritis (OA) in order to reveal changes in biochemical markers of cartilage and inflammation, intraarticularly and in the synovium, in response to a single bout of mechanical joint loading.MethodsThirty-one female subjects with OA of the knee were randomized to non-exercise (NEx) or exercise (Ex) groups. Following acute resistance exercise (25 sets of 10 repetitions at 60% of 1 Repetition Maximum) or none (NEx), peripheral nerve blocks just below the inguinal ligament were applied and two microdialysis catheters were positioned in two different compartments, intraarticularly and peri-synovially. The microdialysis catheters were perfused at a slow rate (2 μl/minute) with a solution of Ringer-acetate and radioactively labelled glucose allowing for determination of relative recovery (RR) and calculation of interstitial concentrations of inflammatory and cartilage biomarkers over a three-hour period.ResultsA significant increase of Interleukin (IL) -10 was discovered in both positions of the knee in the Ex group over the three hours post exercise, whereas IL-10 remained stationary over time in the NEx group. IL-6 and IL-8 displayed significant increases over time regardless of group and position of the catheter. Cartilage oligomeric matrix protein (COMP) decreased intraarticularly in the post exercise period in the Ex group compared to the NEx group.ConclusionsExercise caused an increase in both intraarticular and peri-synovial concentrations of IL-10 in a group of human females with knee OA. This suggests a positive effect of exercise on a chondroprotective anti-inflammatory cytokine response in patients with knee OA and might contribute to explaining the beneficial effect that exercise has on OA.Trial registrationNCT01090375.

Bosentan Improves Exercise Capacity in Adolescents and Adults After Fontan Operation The TEMPO (Treatment With Endothelin Receptor Antagonist in Fontan Patients, a Randomized, Placebo-Controlled, Double-Blind Study Measuring Peak Oxygen Consumption) Study

Background —The Fontan procedure has improved survival in children with functionally univentricular hearts. With time however, complications such as reduced exercise capacity are seen more frequently. Exercise intolerance is multifactorial but pulmonary vascular resistance (PVR) probably plays a crucial role. Elevated PVR has been associated with raised levels of endothelin-1, which are common both before and after Fontan operations. Treatment with endothelin-1 receptor antagonists could theoretically improve cardio-pulmonary hemodynamics and exercise capacity. The aim of this study was therefore to examine the efficacy and safety of bosentan in Fontan patients. Methods and Results —Seventy-five adolescents and adults were randomized 1:1 to 14 weeks treatment with bosentan or placebo. Cardio-pulmonary exercise-test (CPET), functional class, blood samples and quality-of-life questionnaire were evaluated at baseline and at the end of treatment. Sixty-nine patients (92%) completed the study. Peak oxygen consumption increased 2.0 (from 28.7 to 30.7) ml/kg/min in the bosentan group compared to 0.6 (from 28.4 to 29.0) ml/kg/min in the placebo group, p=0.02. CPET time increased 0.48 (from 6.79 to 7.27) vs. 0.08 (from 6.94 to 7.02) minutes, p=0.04. Nine bosentan treated patients improved one functional class, whereas none improved in the placebo group, p=0.0085. Side effects were mild and occurred equally in both groups. No serious adverse effects were seen and no patients had liver enzyme levels above three-fold upper limit. Conclusions —Bosentan improves exercise capacity, exercise time and functional class in Fontan patients without serious adverse events or hepatotoxicity. Clinical Trial Registration Information —www.clinicaltrials.gov. Identifier [NCT01292551][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01292551&atom=%2Fcirculationaha%2Fearly%2F2014%2F10%2F20%2FCIRCULATIONAHA.113.008441.atomBackground— The Fontan procedure has improved survival in children with functionally univentricular hearts. With time, however, complications such as reduced exercise capacity are seen more frequently. Exercise intolerance is multifactorial, but pulmonary vascular resistance probably plays a crucial role. Elevated pulmonary vascular resistance has been associated with raised levels of endothelin-1, which are common both before and after Fontan operations. Treatment with endothelin-1 receptor antagonists could theoretically improve cardiopulmonary hemodynamics and exercise capacity. The aim of this study was therefore to examine the efficacy and safety of bosentan in Fontan patients. Methods and Results— Seventy-five adolescents and adults were randomized 1:1 to 14 weeks of treatment with bosentan or placebo. Cardiopulmonary exercise test, functional class, blood samples, and quality-of-life questionnaires were evaluated at baseline and at the end of treatment. Sixty-nine patients (92%) completed the study. Peak oxygen consumption increased 2.0 mL·kg−1·min−1 (from 28.7 to 30.7 mL·kg−1·min−1) in the bosentan group compared with 0.6 mL·kg−1·min−1 (from 28.4 to 29.0 mL·kg−1·min−1) in the placebo group (P=0.02). Cardiopulmonary exercise test time increased by 0.48 minute (from 6.79 to 7.27 minutes) versus 0.08 minute (from 6.94 to 7.02 minutes; P=0.04). Nine bosentan-treated patients improved 1 functional class, whereas none improved in the placebo group (P=0.0085). Side effects were mild and occurred equally in both groups. No serious adverse effects were seen, and no patients had liver enzyme levels above the 3-fold upper limit. Conclusions— Bosentan improves exercise capacity, exercise time, and functional class in Fontan patients without serious adverse events or hepatotoxicity. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01292551.

Bosentan Improves Exercise Capacity in Adolescents and Adults After Fontan Operation: The TEMPO Study

Background —The Fontan procedure has improved survival in children with functionally univentricular hearts. With time however, complications such as reduced exercise capacity are seen more frequently. Exercise intolerance is multifactorial but pulmonary vascular resistance (PVR) probably plays a crucial role. Elevated PVR has been associated with raised levels of endothelin-1, which are common both before and after Fontan operations. Treatment with endothelin-1 receptor antagonists could theoretically improve cardio-pulmonary hemodynamics and exercise capacity. The aim of this study was therefore to examine the efficacy and safety of bosentan in Fontan patients. Methods and Results —Seventy-five adolescents and adults were randomized 1:1 to 14 weeks treatment with bosentan or placebo. Cardio-pulmonary exercise-test (CPET), functional class, blood samples and quality-of-life questionnaire were evaluated at baseline and at the end of treatment. Sixty-nine patients (92%) completed the study. Peak oxygen consumption increased 2.0 (from 28.7 to 30.7) ml/kg/min in the bosentan group compared to 0.6 (from 28.4 to 29.0) ml/kg/min in the placebo group, p=0.02. CPET time increased 0.48 (from 6.79 to 7.27) vs. 0.08 (from 6.94 to 7.02) minutes, p=0.04. Nine bosentan treated patients improved one functional class, whereas none improved in the placebo group, p=0.0085. Side effects were mild and occurred equally in both groups. No serious adverse effects were seen and no patients had liver enzyme levels above three-fold upper limit. Conclusions —Bosentan improves exercise capacity, exercise time and functional class in Fontan patients without serious adverse events or hepatotoxicity. Clinical Trial Registration Information —www.clinicaltrials.gov. Identifier [NCT01292551][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01292551&atom=%2Fcirculationaha%2Fearly%2F2014%2F10%2F20%2FCIRCULATIONAHA.113.008441.atomBackground— The Fontan procedure has improved survival in children with functionally univentricular hearts. With time, however, complications such as reduced exercise capacity are seen more frequently. Exercise intolerance is multifactorial, but pulmonary vascular resistance probably plays a crucial role. Elevated pulmonary vascular resistance has been associated with raised levels of endothelin-1, which are common both before and after Fontan operations. Treatment with endothelin-1 receptor antagonists could theoretically improve cardiopulmonary hemodynamics and exercise capacity. The aim of this study was therefore to examine the efficacy and safety of bosentan in Fontan patients. Methods and Results— Seventy-five adolescents and adults were randomized 1:1 to 14 weeks of treatment with bosentan or placebo. Cardiopulmonary exercise test, functional class, blood samples, and quality-of-life questionnaires were evaluated at baseline and at the end of treatment. Sixty-nine patients (92%) completed the study. Peak oxygen consumption increased 2.0 mL·kg−1·min−1 (from 28.7 to 30.7 mL·kg−1·min−1) in the bosentan group compared with 0.6 mL·kg−1·min−1 (from 28.4 to 29.0 mL·kg−1·min−1) in the placebo group (P=0.02). Cardiopulmonary exercise test time increased by 0.48 minute (from 6.79 to 7.27 minutes) versus 0.08 minute (from 6.94 to 7.02 minutes; P=0.04). Nine bosentan-treated patients improved 1 functional class, whereas none improved in the placebo group (P=0.0085). Side effects were mild and occurred equally in both groups. No serious adverse effects were seen, and no patients had liver enzyme levels above the 3-fold upper limit. Conclusions— Bosentan improves exercise capacity, exercise time, and functional class in Fontan patients without serious adverse events or hepatotoxicity. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01292551.

Life-long endurance exercise in humans: Circulating levels of inflammatory markers and leg muscle size

Human aging is associated with a loss of skeletal muscle and an increase in circulating inflammatory markers. It is unknown whether endurance training (Tr) can prevent these changes. Therefore we studied 15 old trained (O-Tr) healthy males and, for comparison, 12 old untrained (O-Un), 10 Young-Tr (Y-Tr) and 12 Young-Un (Y-Un). Quadriceps size, VO2 peak, CRP, IL-6, TNF-α and its receptors, suPAR, lipid profile, leucocytes and glucose homeostasis were measured. Tr was associated with an improved insulin profile (p<0.05), and lower leucocyte (p<0.05) and triglyceride levels (p<0.05), independent of age. Aging was associated with poorer glucose control (p<0.05), independent of training. The age-related changes in waist circumference, VO2 peak, cholesterol, LDL, leg muscle size, CRP and IL-6 were counteracted by physical activity (p<0.05). A significant increase in suPAR with age was observed (p<0.05). Most importantly, life-long endurance exercise was associated with a lower level of the inflammatory markers CRP and IL-6 (p<0.05), and with a greater thigh muscle area (p<0.05), compared to age-matched untrained counterparts. These findings in a limited group of individuals suggest that regular physical endurance activity may play a role in reducing some markers of systemic inflammation, even within the normal range, and in maintaining muscle mass with aging.

Local NSAID infusion does not affect protein synthesis and gene expression in human muscle after eccentric exercise

Unaccustomed exercise leads to satellite cell proliferation and increased skeletal muscle protein turnover. Several growth factors and cytokines may be involved in the adaptive responses. Non‐steroidal anti‐inflammatory drugs (NSAIDs) negatively affect muscle regeneration and adaptation in animal models, and inhibit the exercise‐induced satellite cell proliferation and protein synthesis in humans. However, the cellular mechanisms eliciting these responses remain unknown. Eight healthy male volunteers performed 200 maximal eccentric contractions with each leg. To block prostaglandin synthesis locally in the skeletal muscle, indomethacin (NSAID) was infused for 7.5 h via microdialysis catheters into m. vastus lateralis of one leg. Protein synthesis was determined by the incorporation of 1,2‐13C2 leucine into muscle protein from 24 to 28 h post‐exercise. Furthermore, mRNA expression of selected genes was measured in muscle biopsies (5 h and 8 days post‐exercise) by real‐time reverse transcriptase PCR. Myofibrillar and collagen protein synthesis were unaffected by the local NSAID infusion. Five hours post‐exercise, the mRNA expression of cyclooxygenase‐2 (COX2) was sixfold higher in the NSAID leg (P=0.016) compared with the unblocked leg. The expression of growth factors and matrix‐related genes were unaffected by NSAID. Although NSAIDs inhibit the exercise‐induced satellite cell proliferation, we observed only limited effects on gene expression, and on post‐exercise protein synthesis.

Rehabilitation of muscle after injury – the role of anti-inflammatory drugs

Non‐steroidal anti‐inflammatory drugs (NSAIDs) are widely consumed among athletes worldwide in relation to muscle injury and soreness. This review aims to provide an overview of studies investigating their effects on skeletal muscle, in particular the repair processes in injured muscle. Muscle injury occurs in diverse situations and the nature of muscle injuries varies significantly, complicating extrapolations between experimental models and “real life.” Classical muscle strain injuries occur at the interphase between the muscle fibers and connective tissue, most often in the myotendinuous junction, whereas contusion or overload injury can damage both myofibers and intramuscular connective tissue. The role of NSAIDs in muscle repair is complicated by differences in injury models used, variables evaluated, and time point(s) selected for evaluations.

Activated Protein Synthesis and Suppressed Protein Breakdown Signaling in Skeletal Muscle of Critically Ill Patients

Background Skeletal muscle mass is controlled by myostatin and Akt-dependent signaling on mammalian target of rapamycin (mTOR), glycogen synthase kinase 3β (GSK3β) and forkhead box O (FoxO) pathways, but it is unknown how these pathways are regulated in critically ill human muscle. To describe factors involved in muscle mass regulation, we investigated the phosphorylation and expression of key factors in these protein synthesis and breakdown signaling pathways in thigh skeletal muscle of critically ill intensive care unit (ICU) patients compared with healthy controls. Methodology/Principal Findings ICU patients were systemically inflamed, moderately hyperglycemic, received insulin therapy, and showed a tendency to lower plasma branched chain amino acids compared with controls. Using Western blotting we measured Akt, GSK3β, mTOR, ribosomal protein S6 kinase (S6k), eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1), and muscle ring finger protein 1 (MuRF1); and by RT-PCR we determined mRNA expression of, among others, insulin-like growth factor 1 (IGF-1), FoxO 1, 3 and 4, atrogin1, MuRF1, interleukin-6 (IL-6), tumor necrosis factor α (TNF-α) and myostatin. Unexpectedly, in critically ill ICU patients Akt-mTOR-S6k signaling was substantially higher compared with controls. FoxO1 mRNA was higher in patients, whereas FoxO3, atrogin1 and myostatin mRNAs and MuRF1 protein were lower compared with controls. A moderate correlation (r2 = 0.36, p<0.05) between insulin infusion dose and phosphorylated Akt was demonstrated. Conclusions/Significance We present for the first time muscle protein turnover signaling in critically ill ICU patients, and we show signaling pathway activity towards a stimulation of muscle protein synthesis and a somewhat inhibited proteolysis.

Differential satellite cell density of type I and II fibres with lifelong endurance running in old men.

To investigate the influence of lifelong endurance running on the satellite cell pool of type I and type II fibres in healthy human skeletal muscle.

Design and rationale for the PREVAIL study: Effect of e-Health individually tailored encouragements to physical exercise on aerobic fitness among adolescents with congenital heart disease—a randomized clinical trial

Intensive exercise may be an important part of rehabilitation in patients with congenital heart disease (CHD). However, performing regular physical exercise is challenging for many adolescent patients. Consequently, effective exercise encouragements may be needed. Little is known on the effect of e-Health encouragements on physical fitness, physical activity, and health-related quality of life in adolescents. This trial is a nationwide interactive e-Health rehabilitation study lasting 1 year, centered on interactive use of mobile phone and Internet technology. We hypothesize that e-Health encouragements and interactive monitoring of intensive exercise for 1 year can improve physical fitness, physical activity, and health-related quality of life. Two hundred sixteen adolescents (age, 13-16 years) with surgically corrected complex CHD but without significant hemodynamic residual defects and no restrictions to participate in physical activity are in the process of being enrolled by invitation after informed consent. Physical fitness is measured as the maximal oxygen uptake (Vo(2)) at baseline and after 12 months by an assessor blinded to the randomization group. After baseline testing, the patients are 1:1 randomized to an intervention group or a control group. Individually fully automated tailored e-Health encouragements--SMS, Internet, and mobile applications--aimed at increasing physical activity are delivered to the participants in the intervention group once a week. The Banduras Social Cognitive Theory inspires the behavioral theoretical background. The e-Health intervention and the Godfrey cycle ergometer protocol have been feasibility tested and seem applicable to adolescents with CHD. The trial is expected to contribute with new knowledge regarding how physical activity in adolescents with CHD can be increased and, possibly, comorbidity be reduced.