Effects of short-term vibration and hypoxia during high-intensity cycling exercise on circulating levels of angiogenic regulators in humans

Whole Body Vibration Training Has No Effect on Vascular Endothelial and Inflammatory Markers in Young Healthy Women

Background: The aim of the study was to comparatively assess the impact of single and repeated whole body vibration training (WBVT) and training without vibration on changes in the concentration of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), and high-sensitivity C-reactive protein (hsCRP) in healthy, young, non-training women. Methods: The study involved 46 women (age 20.48 ± 1.72 years), who were divided into three groups: the experimental group participating in WBVT (EVG, n = 17); the comparison group performing the same exercises but without the vibration factor (EXG, n = 12); and the control group, which did not participate in any training (CON, n = 17). The program included participation in 36 training sessions conducted over 12 weeks, with a frequency of 3 times per week. In the EVG and EXG groups, venous blood was collected before and after the first and last training sessions, while in the CON group, blood was collected twice at a 3-month interval. Results: No significant changes were observed in the concentrations of the studied markers either after a single or repeated training session in both experimental groups (p > 0.05). Conclusions: The proposed WBVT protocol appears to be a safe form of exercise that does not induce negative inflammatory reactions. The applied vibration stimulus combined with physical exercises did not initiate pro-angiogenic processes or stimulate eNOS activity in healthy women, suggesting that similar studies should be conducted in individuals with circulatory problems or chronic inflammatory diseases.

Exercise builds the scaffold of life: muscle extracellular matrix biomarker responses to physical activity, inactivity, and aging

Skeletal muscle extracellular matrix (ECM) is critical for muscle force production and the regulation of important physiological processes during growth, regeneration, and remodelling. ECM remodelling is a tightly orchestrated process, sensitive to multi-directional tensile and compressive stresses and damaging stimuli, and its assessment can convey important information on rehabilitation effectiveness, injury, and disease. Despite its profound importance, ECM biomarkers are underused in studies examining the effects of exercise, disuse, or aging on muscle function, growth, and structure. This review examines patterns of short- and long-term changes in the synthesis and concentrations of ECM markers in biofluids and tissues, which may be useful for describing the time course of ECM remodelling following physical activity and disuse. Forces imposed on the ECM during physical activity critically affect cell signalling while disuse causes non-optimal adaptations, including connective tissue proliferation. The goal of this review is to inform researchers, and rehabilitation, medical, and exercise practitioners better about the role of ECM biomarkers in research and clinical environments to accelerate the development of targeted physical activity treatments, improve ECM status assessment, and enhance function in aging, injury, and disease.

Skeletal muscle fiber type-specific expressions of mechanosensors integrin-linked kinase, talin, and vinculin and their modulation by loading and environmental conditions in humans

Mechanosensors control muscle integrity as demonstrated in mice. However, no information is available in human muscle about the distribution of mechanosensors and their adaptations to mechanical loading and environmental conditions (hypoxia). Here, we hypothesized that mechanosensors show fiber-type-specific distributions and that loading and environmental conditions specifically regulate mechanosensors. We randomly subjected 28 healthy males to one of the following groups (n = 7 each) consisting of nine loading sessions within 3 weeks: normoxia moderate (NM), normoxia intensive (NI), hypoxia moderate (HM), and hypoxia intensive (HI). We took six biopsies: pre (T0), 4 h (T1), and 24 h (T2) after the third as well as 4 h (T3), 24 h (T4), and 72 h (T5) after the ninth training session. We analyzed subjects' maximal oxygen consumption (V̇O₂ max), maximal power output (Pmax), muscle fiber types and cross-sectional areas (CSA), fiber-type-specific integrin-linked kinase (ILK) localizations as well as ILK, vinculin and talin protein and gene expressions in dependence on loading and environmental conditions. V̇O₂ max increased upon NM and HM, Pmax upon all interventions. Fiber types did not change, whereas CSA increased upon NI and HI, but decreased upon HM. ILK showed a type 2-specific fiber type localization. ILK, vinculin, and talin protein and gene expressions differed depending on loading and environmental conditions. Our data demonstrate that mechanosensors show fiber type-specific distributions and that exercise intensities rather than environmental variables influence their profiles in human muscles. These data are the first of their kind in human muscle and indicate that mechanosensors manage the mechanosensing at a fiber-type-specific resolution and that the intensity of mechanical stimulation has a major impact.

Effect of whole-body vibration training on transcutaneous oxygen levels of the foot in patients with type 2 diabetes: A randomized controlled trial

Whole body vibration (WBV) has been suggested as improving skin and blood flow. This study aimed to determine the effect of exposure to WBV on levels of partial transcutaneous oxygen pressure (TcPO2) in the foot of patients with type 2 diabetes (T2D) within the metabolic control goals. A block randomized, open, two-arm, parallel and controlled clinical trial was conducted. Participants recruited from the Center of Comprehensive Care for the Patient with Diabetes were assessed at the National Institute of Rehabilitation, Mexico City. Control group underwent multidisciplinary care for T2D; experimental group, in addition to the comprehensive diabetes care, was exposed to WBV through an exercise program, attending three times a week for a period of 3 months. TcPO2 was measured in the feet of the participants at baseline and after 12 weeks. A sample of 50 volunteers with recently-diagnosed T2D and similar baseline characteristics (demographic, cardiovascular risk, presence of diabetic polyneuropathy, and indicators of glycemic control and TcPO2) was recruited. The experimental group (n = 27) showed a mean value of 47.7 ± 6.1 mmHg in TcPO2, significantly higher (p = 0.028) than the 44.3 ± 7.5 mmHg of control group (n = 23), at the end of intervention. In conclusion, exposure to WBV promoted an increase and a significant 3 mmHg difference in the foot TcPO2 levels between those subjects with T2D that underwent the 12-week exercise program and those not exposed to the treatment.

Plasma endostatin correlates with hypoxia and mortality in COVID-19-associated acute respiratory failure

Background: The contribution of endothelial injury in the pathogenesis of COVID-19-associated acute respiratory distress syndrome (ARDS) and resulting respiratory failure remains unclear. Plasma endostatin, an endogenous inhibitor of angiogenesis and endothelial dysfunction is upregulated during hypoxia, inflammation and progress of pulmonary disease. Aim: To investigate if plasma endostatin is associated to hypoxia, inflammation and 30-day mortality in patients with severe COVID-19 infection. Method: Samples for blood analysis and plasma endostatin quantification were collected from adult patients with ongoing COVID-19 (n = 109) on admission to intensive care unit (day 1). Demographic characteristics and 30-day mortality data were extracted from medical records. The ability of endostatin to predict mortality was analyzed using receiving operating characteristics and Kaplan–Meier analysis with a cutoff at 46.2 ng/ml was used to analyze the association to survival. Results: Plasma endostatin levels correlated with; PaO₂/FiO2 (r = -0.3, p < 0.001), arterial oxygen tension (r = -0.2, p = 0.01), lactate (r = 0.2, p = 0.04), C-reactive protein (r = 0.2, p = 0.04), ferritin (r = 0.2, p = 0.09), D-dimer (r = 0.2, p = 0.08) and IL-6 (r = 0.4, p < 0.001). Nonsurvivors at 30 days had higher plasma endostatin levels than survivors (72 ± 26 vs 56 ± 16 ng/ml, p = 0.01). Receiving operating characteristic curve (area under the curve 0.7) showed that plasma endostatin >46.2 ng/ml predicts mortality with a sensitivity of 92% and specificity of 71%. In patients with plasma endostatin >46.2 ng/ml probability of survival was lower (p = 0.02) in comparison to those with endostatin <46.2 ng/ml. Conclusion: Our results suggest that plasma endostatin is an early biomarker for disease severity in COVID-19.

Acute Exhaustive Exercise under Normoxic and Normobaric Hypoxic Conditions Differentially Regulates Angiogenic Biomarkers in Humans

Background and Objectives: Angiogenesis describes the outgrowth of new capillaries from already existing ones. Different biomarkers regulate this process. Physical exercise and hypoxia are key stimuli for the activation of different angiogenic molecules, such as the vascular endothelial growth factor (VEGF). matrix metalloproteases (MMPs)-2 and -9 or the extracellular matrix cleavage fragment endostatin. The present study aimed to investigate influences of short-term, intensive cycling exercise under both normoxic and normobaric hypoxic conditions on the mentioned parameters. Materials and Methods: Twelve male subjects (age: 23.3 ± 2.0 years) participated in the study. All subjects conducted four intensive cycling tests until individual exhaustion in a randomized order under the following conditions: normoxia, 2000 m, 3000 m and 4000 m above sea level. Blood samples were taken before (pre) and 10 min, 30 min, 60 min and 240 min post exercise and were analyzed by ELISA. Results: VEGF showed a significantly reduced concentration compared to the pre-value solely under 4000 m at 10 min post exercise. MMP-2 showed significantly reduced concentrations at 240 min post exercise under 4000 m. MMP-9 increased at 240 min post exercise under both 2000 m and 4000 m conditions. Endostatin was significantly increased at 10 min post exercise independently of the applied stimulus. Conclusions: The presented data show that intensive short-term exercise bouts facilitate the bioavailability of angiogenic, ECM (extracellular matrix)-related biomarkers. This finding is interesting for both health- and performance-related research as it demonstrates the positive effects of intensive short exercise interventions.

The effect of vibration cycle ergometry on pulmonary 2 kinetics, isokinetic knee torque, and lower extremity explosive power

Whole-body vibration training is useful for eliciting additional training benefits, but whether vibration-based cycle ergometry would elicit similar benefits has been largely unexplored. Thirteen participants were recruited to investigate differences in vibration (VB) cycle ergometry compared to non-vibration (NV) cycle ergometry with regards to oxygen uptake (V̇O2) kinetics, rating of perceived exertion (RPE), heart rate (HR), jumping height, and isokinetic knee joint torque at different intensities and cadences. Meaningful ergometer differences (in favour of VB) were evident for maximal steady state V̇O2 HR and RPE, but not for the phase II V̇O2 time constant. No meaningful changes were observed for jumping height or isokinetic knee joint torque. The noteworthy increases in V̇O2, RPE and HR when using VB ergometry, specifically at higher cadences, and independent of intensity domain, may be linked to changes in muscle fibre recruitment or muscle activation. Practitioner summary: Traditional vibration training has purported various beneficial effects, but whether such effects transferred to cycling ergometry was under-researched. Vibration-based cycle ergometry may be a viable method of additionally stressing the cardiovascular system at the same relative intensity compared to non-vibration cycling.

Whole-body vibration preconditioning reduces the formation and delays the manifestation of high-altitude-induced venous gas emboli

NEW FINDINGS

What is the central question of this study? Is performing a 30-min whole-body vibration (WBV) prior to a continuous 90-min exposure at 24,000 ft sufficient to prevent venous gas emboli (VGE) formation? What is the main finding and its importance? WBV preconditioning significantly reduces the formation and delays the manifestation of high-altitude-induced VGE. This study suggests that WBV is an effective strategy in lowering decompression stress.

ABSTRACT

Rapid decompression may give rise to formation of venous gas emboli (VGE) and resultantly, increase the risk of sustaining decompression sickness. Preconditioning aims at lowering the prevalence of VGE during decompression. The purpose of this study was to investigate the efficacy of whole-body vibration (WBV) preconditioning on high-altitude-induced VGE. Eight male subjects performed, on separate days in a randomised order, three preconditioning strategies: 40-min seated-rest (control), 30-min seated-rest followed by 150 knee-squats performed over a 10-min period (exercise) and 30-min WBV proceeded by a 10-min seated-rest. Thereafter, subjects were exposed to an altitude of 24,000 ft (7315 m) for 90 min whilst laying in a supine position and breathing 100% oxygen. VGE were assessed ultrasonically both during supine rest (5-min intervals) and after three fast, unloaded knee-bends (15-min intervals) and were scored using a 5-grade scale and evaluated using the Kisman Integrated Severity Score (KISS). There was a significant difference in VGE grade (P < 0.001), time to VGE manifestation (P = 0.014) and KISS score following knee-bends (P = 0.002) across protocols, with a trend in KISS score during supine rest (P = 0.070). WBV resulted in lower VGE grades (median (range), 1 (0-3)) and KISS score (2.69 ± 4.56 a.u.) compared with control (2 (1-3), P = 0.002; 12.86 ± 8.40 a.u., P = 0.011) and exercise (3 (2-4) , P < 0.001; 22.04 ± 13.45 a.u., P = 0.002). VGE were detected earlier during control (15 ± 14 min, P = 0.024) and exercise (17 ± 24 min, P = 0.032) than WBV (54 ± 38 min). Performing a 30-min WBV prior to a 90-min continuous exposure at 24,000 ft both delays the manifestation and reduces the formation of VGE compared with control and exercise preconditioning.

The effects of whole-body vibration on wound healing in a mouse pressure ulcer model

BACKGROUND

Pressure ulcers are one of the most common complications of immobility resulting from pressure and shear. Whole-body vibration (WBV) has been shown to increase skin blood flow but little information is known about its effect on pressure ulcers. This study investigated the effects of WBV on wound healing in a mouse pressure ulcer model.

METHODS

Two cycles of ischemia-reperfusion were performed by external application of two magnetic plates to dorsal skin to induce stage II pressure ulcers characterized by partial-thickness skin loss with exposed dermis. A total of 32 male ICR mice were randomly and equally divided into untreated control and the WBV groups. Immediately after the completion of 2-cycle ischemia-reperfusion injury, mice in the WBV group participated in a WBV program using a vibrator (frequency 45 Hz, peak acceleration 0.4 g, vertical motion) for 30 min/day and 5 consecutive days/week. At days 7 and 14 post-ulceration, wound closure rate was assessed. Wound tissues were harvested for determination of collagen deposition in Masson's trichrome stained sections, neutrophil infiltration and capillary density in hematoxylin and eosin-stained sections, as well as TNF-α and VEGF levels using ELISA.

RESULTS

TNF-α levels and neutrophil infiltration were significantly decreased in wounds on days 7 and 14 of WBV treatment. Moreover, wound closure rate and collagen deposition were remarkably accelerated on day 14. Tissue VEGF and capillary density were unaffected by WBV at either time point.

CONCLUSIONS

These findings suggest that WBV has the potential to promote the healing process of stage II pressure ulcers, as evidenced by attenuation of wound inflammation and enhancement collagen deposition.

The effects of vibration on efficiency in off-road cyclists

Objectives

The aim of this study was to investigate whether vibration significantly affected the efficiency of off-road cyclists.

Patients and methods

Eight male mountain cyclists (mean age 21.1±1 years; range, 19 to 22 years) between August 2017 and November 2017 were included. The experimental protocol included four testing sessions with a one-day interval between testing sessions: a familiarization session; performance of submaximal tests; performance of maximal graded exercise test; and a 30-min mountain bike trial performed with vibration or without vibration. Physiological measures including volume of oxygen uptake (VO₂), volume of ₂), VO₂, VCO₂, heart rate, respiratory exchange ratio, rating of perceived exertion, and gross efficiency (GE) were compared between the trials performed with vibration or without vibration.

Results

There was a significant increase in the GE with the addition of intermittent vibration, particularly over the last 15 min of the cycling trial (p<0.05). There were no significant effects of vibration on other parameters.

Conclusion

This study demonstrates that addition of intermittent vibration may provide positive benefits in improving GE during a 30-min submaximal cycling trial.

Cardiorespiratory, Metabolic and Perceived Responses to Electrical Stimulation of Upper-Body Muscles While Performing Arm Cycling

This study was designed to assess systemic cardio-respiratory, metabolic and perceived responses to incremental arm cycling with concurrent electrical myostimulation (EMS). Eleven participants (24 ± 3 yrs; 182 ± 10 cm; 86 ± 16.8 kg) performed two incremental tests involving arm cycling until volitional exhaustion was reached with and without EMS of upper-body muscles. The peak power output was 10.1% lower during arm cycling with (128 ± 30 W) than without EMS (141 ± 25 W, p = 0.01; d = 0.47). In addition, the heart rate (2-9%), oxygen uptake (7-15%), blood lactate concentration (8-46%) and ratings of perceived exertion (4-14%) while performing submaximal arm cycling with EMS were all higher with than without EMS (all p < 0.05). Upon exhaustion, the heart rate, oxygen uptake, lactate concentration, and ratings of perceived exertion did not differ between the two conditions (all p > 0.05). In conclusion, arm cycling with EMS induced more pronounced cardio-respiratory, metabolic and perceived responses, especially during submaximal arm cycling. This form of exercise with stimulation might be beneficial for a variety of athletes competing in sports involving considerable generation of work by the upper body (e.g., kayaking, cross-country skiing, swimming, rowing and various parasports).

Effect of Age and Acute Exercise on Circulating Angioregulatory Factors

The balance of angiogenic factors, including vascular endothelial growth factor (VEGF), and angiostatic factors, like thrombospondin-1 (TSP-1) and endostatin, controls striated muscle angiogenic responses to exercise training. The effect of age on circulating levels of these factors following a bout of exercise is unclear. The authors hypothesized that older adults would have lower circulating VEGF but higher TSP-1 and endostatin after exercise compared with young adults. Ten young and nine older participants cycled for 45 min at 60% estimated HRmax. Serum [VEGF], [TSP-1], and [endostatin] obtained before (PREX), immediately after (POSTX0), and 3 hr after (POSTX3) exercise were analyzed. [VEGF] increased in older adults only from PREX to POSTX0 (p < .05). [TSP-1] increased in both age groups (p < .05). There was no effect of age or exercise on [endostatin]. In conclusion, immediately after exercise, both groups had a similar increase in [TSP-1], but [VEGF] increased in older adults only.

Whole-Body Vibration Training Increases Stem/Progenitor Cell Circulation Levels and May Attenuate Inflammation

INTRODUCTION

Whole-body vibration training (WBVT) may benefit individuals with difficulty participating in physical exercise. The objective was to explore the effects of WBVT on circulating stem/progenitor cell (CPC) and cytokine levels.

METHODS

Healthy male subjects each performed three activities randomly on separate days: (1) standing platform vibration, (2) repetitive leg squat exercise; and (3) in combination. Pre- and post-activity blood samples were drawn. Cell populations were characterized using flow cytometry. Biomarkers were analyzed using enzyme-linked immunosorbent assays.

RESULTS

CPC levels increased significantly 21% with exercise alone (1465 ± 202-1770 ± 221 cells/mL; P = 0.017) and 33% with vibration alone in younger participants (1918 ± 341-2559 ± 496; P = 0.02). Angiogenic CPCs increased 39% during combined activity in younger (633 ± 128-882 ± 181; P = 0.05). Non-angiogenic CPCs increased 42% with vibration alone in younger (1181 ± 222-1677 ± 342; P = 0.04), but 32% with exercise alone in older participants (801 ± 251-1053 ± 325; P = 0.05). With vibration alone, anti-inflammatory cytokine interleukin-10 increased significantly (P < 0.03), although inflammatory interleukin-6 decreased (P = 0.056); tumor necrosis factor-alpha (P < 0.01) and vascular endothelial growth factor levels increased (P < 0.005), which are synergistically pro-angiogenic.

CONCLUSIONS

WBVT may have positive vascular and anti-inflammatory effects. WBVT could augment or serve as an exercise surrogate in warfighters and others who cannot fully participate in exercise programs, having important implications in military health.

Preconditioning Effect of High-Intensity Interval Training (HIIT) and Berberine Supplementation on the Gene Expression of Angiogenesis Regulators and Caspase-3 Protein in the Rats with Myocardial Ischemia-Reperfusion (IR) Injury

Objective

It has been shown that angiogenesis is a desirable treatment for patients with ischemic heart disease. We set out to investigate the impact of high-intensity interval training (HIIT) and berberine supplementation on the gene expression of angiogenesis-related factors and caspase-3 protein in rats suffering from myocardial ischemic-reperfusion injury.

Methods

Fifty rats were divided into the following groups: (1) trained, (2) berberine supplemented, (3) combined, and (4) IR. Each cohort underwent five sessions of HIIT per week for a duration of 8 weeks followed by induction of ischemia. Seven days after completion of reperfusion, changes in the gene expression of angiogenesis-related factors and caspase-3 protein were evaluated in the heart tissue.

Results

We observed a significant difference between four groups in the transcript levels of vascular endothelial cell growth factor (VEGF), fibroblast growth factor-2 (FGF2), and thrombospondin-1(TSP-1) (p ≤ 0.05). However, the difference in endostatin (ENDO) levels was not significant among the groups despite a discernible reduction (p ≥ 0.05). Moreover, caspase-3 protein and infarct size were significantly reduced in the intervention groups (p ≤ 0.05), and cardiac function increased in response to these interventions.

Conclusion

The treatments exert their effect, likely, by reducing caspase-3 protein and increasing the expression of angiogenesis-promoting factors, concomitant with a reduction in inhibitors of the process.

Enhanced Blood Supply Through Lower Body Negative Pressure During Slow-Paced, High Load Leg Press Exercise Alters the Response of Muscle AMPK and Circulating Angiogenic Factors

Lower body negative pressure (LBNP) is an established method of simulating the gravitational effects of orthostasis on the cardiovascular system during space flight or at supine body position on Earth. We hypothesized that LBNP added onto leg press exercise would promote leg muscle perfusion, stimulate oxygen consumption, and modify acute molecular responses. Eighteen subjects performed fifteen slow-paced concentric (4 s) and eccentric contractions (4 s) without or with 40 mmHg LBNP. Force corresponding to 6% of the one-repetition maximum (1-RM) at knee flexion gradually increased to 60% 1-RM within the first half of the range of motion, thereafter remaining constant. AMPK and P-AMPK protein expression was determined in biopsies of vastus lateralis. Venous blood samples were used to measure angiogenic factors. Physiological responses to LBNP included an elevated EMG amplitude, higher heart rate and doubling of the cardiac output compared to control (p < 0.001). Muscle total hemoglobin was increased by around 20 μmol/l vs. control (p < 0.001), accompanied by decreasing tissue oxygen saturation and elevated oxygen uptake (p < 0.05). MMP-2 levels were reduced, and the ratio of P-AMPK to AMPK elevated after exercise with LBNP (p < 0.05). MMP-9 similarly increased in both groups, whereas endostatin was only elevated in the control group (p < 0.05). Our results indicate facilitated peripheral blood supply and higher oxygen exploitation leading to activation of the energy sensor AMPK and differential regulation of angiogenic factors involved in muscle tissue remodeling and capillary growth. Simulating orthostasis with LBNP might promote beneficial structural adaptations of skeletal muscles during resistance exercise and contribute to future exercise countermeasures achieving increased muscle strength and endurance during space flight.

VEGF and TNF-α Responses to Acute and Chronic Aerobic Exercise in the Patients with Multiple Sclerosis

Background: Aerobic exercise has been shown to decrease the functional disorders related to multiple sclerosis (MS). Nevertheless, the effect of aerobic exercise training on the cytokines and neuroprotective mediators associated with the disease activity has remained relatively unknown. Objectives: The present research was conducted to evaluate the responses of the vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α) to single-bout and six-week aerobic exercise training in the patients with MS. Methods: Totally, 20 subjects ((n = 10) patients with MS and (n = 10) controls) who were matched in terms of gender, weight, body mass, and age were included in the study. Participants received aerobic exercise training at approximately 60% of VO2max in 30-min sessions 3 times a week for six weeks. Serum concentrations of the VEGF and TNF-α were analyzed pre- and post-exercise training (in the first session and after 18 sessions of the study). Results: Serum concentration of the TNF-α decreased significantly after a single bout and 6-week aerobic exercise training (P = 0.002 and P = 0.005) in the intervention group. Serum concentration of the VEGF increased significantly only after exercise in the first and 18th sessions in the intervention group (P = 0.017 and P = 0.022). Conclusions: Our results revealed that exercise may influence the VEGF regulation in patients with MS. Although, further research is needed to determine the effect of exercise on the immune variables in patients with MS.

Implications of Skeletal Muscle Extracellular Matrix Remodeling in Metabolic Disorders: Diabetes Perspective

The extracellular matrix (ECM) provides a scaffold for cells, controlling biological processes and providing structural as well as mechanical support to surrounding cells. Disruption of ECM homeostasis results in several pathological conditions. Skeletal muscle ECM is a complex network comprising collagens, proteoglycans, glycoproteins, and elastin. Recent therapeutic approaches targeting ECM remodeling have been extensively deliberated. Various ECM components are typically found to be augmented in the skeletal muscle of obese and/or diabetic humans. Skeletal muscle ECM remodeling is thought to be a feature of the pathogenic milieu allied with metabolic dysregulation, obesity, and eventual diabetes. This narrative review explores the current understanding of key components of skeletal muscle ECM and their specific roles in the regulation of metabolic diseases. Additionally, we discuss muscle-specific integrins and their role in the regulation of insulin sensitivity. A better understanding of the importance of skeletal muscle ECM remodeling, integrin signaling, and other factors that regulate insulin activity may help in the development of novel therapeutics for managing diabetes and other metabolic disorders.

Endostatin predicts mortality in patients with acute dyspnea - A cohort study of patients seeking care in emergency departments

BACKGROUND

Increased levels of circulating endostatin predicts cardiovascular morbidity and impaired kidney function in the general population. The utility of endostatin as a risk marker for mortality in the emergency department (ED) has not been reported.

AIM

Our main aim was to study the association between plasma endostatin and 90-day mortality in an unselected cohort of patients admitted to the ED for acute dyspnea. Design Circulating endostatin was analyzed in plasma from 1710 adults and related to 90-day mortality in Cox proportional hazard models adjusted for age, sex, body mass index, oxygen saturation, respiratory rate, body temperature, C-reactive protein, lactate, creatinine and medical priority according to the Medical Emergency Triage and Treatment System-Adult score (METTS-A). The predictive value of endostatin for mortality was evaluated with receiver operating characteristic (ROC) analysis and compared with the clinical triage scoring system and age.

RESULTS

Each one standard deviation increment of endostatin was associated with a HR of 2.12 (95% CI 1.31-3.44 p < 0.01) for 90-day mortality after full adjustment. Levels of endostatin were significantly increased in the group of patients with highest METTS-A (p < 0.001). When tested for the outcome 90-day mortality, the area under the ROC curve (AUC) was 0.616 for METTS-A, 0.701 for endostatin, 0.708 for METTS -A and age and 0.738 for METTS-A, age and levels of endostatin.

CONCLUSIONS

In an unselected cohort of patients admitted to the ED with acute dyspnea, endostatin had a string association to 90-day mortality and improved prediction of 90-day mortality in the ED beyond the clinical triage scoring system and age with 3%.

Vibration Cycling Did Not Affect Energy Demands Compared to Normal Cycling During Maximal Graded Test

The aim of this study was to compare the physiological responses between a vibration induced cycling step protocol (Vib) and normal cycling (without vibration, no-Vib). Eighteen moderate trained males (age 24.1 ± 4.3 years; weight 76.5 ± 10.5 kg; height 178.0 ± 6.4 cm) have participated in this study. They randomly performed two gradual maximal exercise tests on two separate days using a new bike that automatically induces vibration cycling and the Corival cycle ergometer. The choice of two different bikes was made because of the impossibility to recreate the same power output without altering the cycling cadence on the vibration Bike. Both protocols were matched for power output and cycling cadence incrementations. Oxygen uptake (VO₂), carbon dioxide production (VCO₂), ventilation (VE), heart rate (HR), blood lactate and rating of perceived exertion (RPE) during each stage were continuously recorded. No statistical differences were founded for all variables when comparing the Vib to no-Vib trials, except a higher ventilation during the vibration trial at submaximal levels. The results of this study do not confirm those of previous studies stated that Vib increased metabolic demands during cycling exercise. Added vibration stimulus to an incremental cycling protocol does not affect physiological parameters.

Evidence for skeletal muscle fiber type-specific expressions of mechanosensors

Mechanosensors govern muscle tissue integrity and constitute a subcellular structure known as costameres. Costameres physically link the muscle extracellular matrix to contractile and signaling 'hubs' inside muscle fibers mainly via integrins and are localized beneath sarcolemmas of muscle fibers. Costameres are the main mechanosensors converting mechanical cues into biological events. However, the fiber type-specific costamere architecture in muscles is unexplored. We hypothesized that fiber types differ in the expression of genes coding for costamere components. By coupling laser microdissection to a multiplex tandem qPCR approach, we demonstrate that type 1 and type 2 fibers indeed show substantial differences in their mechanosensor complexes. We confirmed these data by fiber type population-specific protein analysis and confocal microscopy-based localization studies. We further show that knockdown of the costamere gene integrin-linked kinase (Ilk) in muscle precursor cells results in significantly increased slow-myosin-coding Myh7 gene, while the fast-myosin-coding genes Myh1, Myh2, and Myh4 are downregulated. In parallel, protein synthesis-enhancing signaling molecules (p-mTORSer2448, p < 0.05; p-P70S6KThr389, tendency with p < 0.1) were reduced upon Ilk knockdown. However, overexpression of slow type-inducing NFATc1 in muscle precursor cells did not change Ilk or other costamere gene expressions. In addition, we demonstrate fiber type-specific costamere gene regulation upon mechanical loading and unloading conditions. Our data imply that costamere genes, such as Ilk, are involved in the control of muscle fiber characteristics. Further, they identify costameres as muscle fiber type-specific loading management 'hubs' and may explain adaptation differences of muscle fiber types to mechanical (un)loading.

Whole-body vibration training - better care for COPD patients: a systematic review and meta-analysis

Purpose

Whole-body vibrating training (WBVT) is a modality aiming to improve neuromuscular performance of patients with COPD. However, a consensus on the effects of WBVT has not been reached. We aimed to clarify the effects of WBVT on functional exercise capacity, pulmonary function, and quality of life in COPD patients.

Patients and methods

PubMed, Web of Science, and EMBASE were searched through April 5, 2018. We calculated the pooled weight mean difference (WMD) using a random-effects model. Quality assessment and publication bias analyses were also performed.

Results

We included eight randomized control trials involving 365 patients. Compared with control group, WBVT increased 6-minute walking distance (6-MWD) (WMD: 62.14 m; 95% CI: 48.12–76.16; P<0.001), the change of 6-MWD (Δ6-MWD) (WMD: 42.33 m; 95% CI: 15.21–69.45; P=0.002), the change of the time to finish five repeated sit-to-stand tests (WMD: −2.07 seconds; 95% CI: −4.00 to −0.05; P=0.04), and decreased the change of St George’s Respiratory Questionnaire score (WMD: −6.65 points; 95% CI: −10.52 to −2.78; P<0.001). However, no significant difference was found between the two groups regarding forced expired volume in 1 second (FEV₁) (% predicated), change of FEV₁ (% predicated), sit-to-stand test, 6-MWD (% predicated), change of 6-MWD (% predicated), St George’s Respiratory Questionnaire score, COPD Assessment Test score, and change of COPD Assessment Test score.

Conclusion

WBVT has beneficial effects on functional exercise capacity for COPD patients.

Are mechanically sensitive regulators involved in the function and (patho)physiology of cerebral palsy-related contractures?

Skeletal muscle tissue is mechanosensitive, as it is able to sense mechanical impacts and to translate these into biochemical signals making the tissue adapt. Among its mechanosensitive nature, skeletal muscle tissue is the largest metabolic organ of the human body. Disturbances in skeletal muscle mechanosensing and metabolism cause and contribute to many diseases, i.e. muscular dystrophies/myopathies, cardiovascular diseases, COPD or diabetes mellitus type 2. A less commonly focused muscle-related disorder is clinically known as muscle contractures that derive from cerebral palsy (CP) conditions in young and adults. Muscle contractures are characterized by gradually increasing passive muscle stiffness resulting in complete fixation of joints. Different mechanisms have been identified in CP-related contractures, i.e. altered calcium handling, altered metabolism or altered titin regulation. The muscle-related extracellular matrix (ECM), specifically collagens, plays a role in CP-related contractures. Herein, we focus on mechanically sensitive complexes, known as costameres (Cstms), and discuss their potential role in CP-related contractures. We extend our discussion to the ECM due to the limited knowledge of its role in CP-related contractures. The aims of this review are (1) to summarize CP-related contracture mechanisms, (2) to raise novel hypotheses on the genesis of contractures with a focus on Cstms, and (3) to stimulate novel approaches to study CP-related contractures.

Effect of acute and chronic exercise on plasma matrix metalloproteinase and total antioxidant levels

The relationship between acute and chronic exercise and expression of matrix metalloproteinases (MMPs) in muscles is unknown. There happen some alterations in the oxidant-antioxidant balance due to exercise. This study aimed to investigate the levels of MMP-1, tissue inhibitors of metalloproteinases (TIMP-1), hyaluronic acid (HA), total antioxidant status (TAS), and total oxidant status (TOS) following acute and chronic exercising in rats. Twenty-six Wistar Albino male rats were divided in to three groups: control, acute, and chronic groups. In acute group, treadmill exercise was performed 3 days/wk, 10 min/day for 1 week. In chronic group, exercise performed 7 days/wk, 60 min/day for 4 weeks. At the end of the experiment, plasma MMP-1, TIMP-1, HA, TAS, and TOS levels were measured. In current study, the MMP-1, TIMP-1, HA, and TOS levels not observed statistically significant difference among all groups, but in chronic group, there was a significantly difference (P<0.05) between the control and experimental groups in terms of TAS and oxidative stress index (OSI) levels. TAS, TOS, and OSI levels were significantly different between control and chronic exercise group (P<0.01, P<0.05, and P<0.01, respectively). According to these results, we can say acute and chronic exercise does not effect on plasma MMP-1, TIMP-1, and HA levels.

Endostatin: a promising biomarker in the cardiovascular continuum?

The current review article aims to provide an up-to-date summary of previous studies in humans that have reported the association between circulating endostatin levels and different cardiovascular phenotypes. We also aim to provide suggestions for future directions of future research evaluating endostatin as a clinically relevant cardiovascular biomarker. With a few exceptions, higher circulating levels of endostatin seem to reflect vascular and myocardial damage, and a worsened prognosis for cardiovascular events or mortality in individuals with hypertension, diabetes, kidney disease, cardiovascular disease, as well as in the general population. Circulating endostatin seems to be a promising biomarker for cardiovascular pathology, but there is not enough evidence to date to support the use of endostatin measurements in clinical practice.

Nordic walking increases circulating VEGF more than traditional walking training in postmenopause

OBJECTIVES

Nordic walking (NW) is widely practiced by postmenopausal women. Its effects are peculiar owing to the involvement of more muscle groups than in traditional walking training (WT). Since mechanical load promotes secretion of vascular endothelial growth factor (VEGF) from both skeletal muscle and muscle endothelium, the aim of the study was to compare the effect of NW and WT on VEGF levels.

METHOD

Thirty postmenopausal women were randomly assigned to NW or WT. Both groups trained 40-50 min/day, three times per week, at a mean intensity of 12 on a 15-category scale of the ratings of perceived exertion. Since VEGF is also released from adipocytes, anthropometric parameters were assessed.

RESULTS

NW increased circulating VEGF more than WT (p = 0.041). Furthermore, both study groups exhibited an average decrease in weight (p = 0.023), body mass index (p = 0.024), hip circumference (p = 0.001), and arm fat index, although WT participants had higher values for this index at baseline (p < 0.001) and thus exhibited a greater net decrease compared with the NW participants (p < 0.011).

CONCLUSIONS

These data imply that NW increases the level of circulating VEGF more than does traditional walking when the intensity of training is equivalent.

Gelatinases and physical exercise: A systematic review of evidence from human studies

BACKGROUND

Matrix metalloproteinases (MMPs), particularly gelatinase A (MMP-2) and gelatinase B (MMP-9), as well as their tissue inhibitors (TIMP-1 and TIMP-2), are involved in the development of skeletal muscle tissue, in the repair process after muscle injury and in the adaptive modifications induced by physical exercise in skeletal muscle. This paper aims at reviewing results from human studies that investigated the role of gelatinases and their inhibitors in skeletal muscle response to acute physical exercise or training.

METHODS

Electronic databases PubMed/MEDLINE, Scopus and Web of Science were searched for papers published between January 2000 and February 2017. The papers were eligible when reporting human studies in which MMP-2 and/or MMP-9 and/or the inhibitors TIMP-1/TIMP-2 were evaluated, in blood or muscular tissue, before and after acute physical exercise or before and after a period of structured physical training. We included studies on healthy subjects and patients with chronic metabolic diseases (obesity, diabetes mellitus, metabolic syndrome-MS) or asymptomatic coronary artery disease. We excluded studies on patients with neurological, rheumatologic or neoplastic diseases.

RESULTS

Studies conducted on muscle biopsies showed an early stimulation of MMP-9 gene transcription as a result of acute exercise, whereas MMP-2 and TIMP transcription resulted from regular repetition of exercise over time. Studies on serum or plasma level of gelatinases and their inhibitors showed an early release of MMP-9 after acute exercise of sufficient intensity, while data on MMP-2 and TIMP were more contrasting. Most of the studies dealing with the effect of training indicated a trend toward reduction in blood gelatinase levels, once again more clear for MMP-9. This result was related to an anti-inflammatory effect of regular exercise and was more evident when training consisted of aerobic activities. This study has limitations: as the initial selection was done through titles and abstracts, incomplete retrieval cannot be excluded, as well as we cannot exclude bias due to selective reporting within studies.

CONCLUSION

A better knowledge of the molecular events activated by different types of acute exercise and regular training could be of great relevance in order to maximize the benefits of physical activity in healthy subjects and patients.

Cardioprotective Effect of Crocin Combined with Voluntary Exercise in Rat: Role of Mir-126 and Mir-210 in Heart Angiogenesis

Background

Crocin is reported to have a wide range of biological activities such as cardiovascular protection. Recent epidemiologic studies have shown that exercise reduces cardiovascular morbidity and mortality in the general population.

Objective

The aim of this study was to evaluate the effect of crocin and voluntary exercise on miR-126 and miR-210 expression levels and angiogenesis in the heart tissue.

Methods

Animals were divided into 4 groups: control, exercise, crocin, and exercise-crocin. Animals received oral administration of crocin (50 mg/kg) or performed voluntary exercise alone or together for 8 weeks. Akt, ERK1/2 protein levels, miR-126 and miR-210 expression were measured in the heart tissue. Immunohistochemical method was used to detect CD31 in the heart tissue.

Results

Akt and ERK1/2 levels of the heart tissue were higher in crocin treated group and voluntary exercise trained group after 8 weeks. Combination of crocin and exercise also significantly enhanced Akt and ERK1/2 levels in the heart tissue. MiR-126, miR-210 expression and CD31 in the heart increased in both crocin and voluntary exercise groups compared with control group. In addition, combination of exercise and crocin amplified their effect on miR-126 and miR-210 expression, and angiogenesis.

Conclusion

Crocin and voluntary exercise improve heart angiogenesis possibly through enhancement of miR-126 and miR-210 expression. Voluntary exercise and diet supplementation with crocin could have beneficial effects in prevention of cardiovascular disease.

FSTL1 as a Potential Mediator of Exercise-Induced Cardioprotection in Post-Myocardial Infarction Rats

Exercise training has been reported to ameliorate heart dysfunction in both humans and animals after myocardial infarction (MI), but the underlying mechanisms are poorly understood. Follistatin-like1 (FSTL1) is a cardioprotective factor against ischemic injury and is induced in cardiomyocytes and skeletal muscle in ischemic and hypoxic conditions. To test the hypothesis that FSTL1 may be a molecular link between exercise and improved heart function post MI, we subjected MI-rats, induced by left coronary artery ligation, to two modes of exercise: intermittent aerobic exercise (IAE) or mechanical vibration training (MVT), for four weeks and examined the relevance of FSTL1 to exercise-mediated cardiac effects. Exercise improved the functional performance, reduced fibrosis of MI-hearts and induced FSTL1 expression, the TGFβ-Smad2/3 signaling and angiogenesis in myocardium. In gastrocnemius, exercise increased the cross-sectional area of myocytes and FSTL1 expression. Importantly, exercise increased circulating FSTL1 levels, which were positively correlated with the skeletal muscle FSTL1 expression and negatively correlated with heart fibrosis. Overall, the IAE was more effective than that of MVT in cardioprotection. Finally, exogenous FSTL1 administration directly improved angiogenesis as well as functionality of post-MI hearts. Taken together, we have demonstrated that FSTL1 is a potential mediator of exercise-induced cardioprotection in post-MI rats.

The muscle contraction mode determines lymphangiogenesis differentially in rat skeletal and cardiac muscles by modifying local lymphatic extracellular matrix microenvironments

AIM

Lymphatic vessels are of special importance for tissue homeostasis, and increases of their density may foster tissue regeneration. Exercise could be a relevant tool to increase lymphatic vessel density (LVD); however, a significant lack of knowledge remains to understand lymphangiogenesis in skeletal muscles upon training. Interestingly, training-induced lymphangiogenesis has never been studied in the heart. We studied lymphangiogenesis and LVD upon chronic concentric and chronic eccentric muscle contractions in both rat skeletal (Mm. Edl and Sol) and cardiac muscles.

METHODS/RESULTS

We found that LVD decreased in both skeletal muscles specifically upon eccentric training, while this contraction increased LVD in cardiac tissue. These observations were supported by opposing local remodelling of lymphatic vessel-specific extracellular matrix components in skeletal and cardiac muscles and protein levels of lymphatic markers (Lyve-1, Pdpn, Vegf-C/D). Confocal microscopy further revealed transformations of lymphatic vessels into vessels expressing both blood (Cav-1) and lymphatic (Vegfr-3) markers upon eccentric training specifically in skeletal muscles. In addition and phenotype supportive, we found increased inflammation (NF-κB/p65, Il-1β, Ifn-γ, Tnf-α and MPO(+) cells) in eccentrically stressed skeletal, but decreased levels in cardiac muscles.

CONCLUSION

Our data provide novel mechanistic insights into lymphangiogenic processes in skeletal and cardiac muscles upon chronic muscle contraction modes and demonstrate that both tissues adapt in opposing manners specifically to eccentric training. These data are highly relevant for clinical applications, because eccentric training serves as a sufficient strategy to increase LVD and to decrease inflammation in cardiac tissue, for example in order to reduce tissue abortion in transplantation settings.

Proteases decode the extracellular matrix cryptome

The extracellular matrix is comprised of 1100 core-matrisome and matrisome-associated proteins and of glycosaminoglycans. This structural scaffold contributes to the organization and mechanical properties of tissues and modulates cell behavior. The extracellular matrix is dynamic and undergoes constant remodeling, which leads to diseases if uncontrolled. Bioactive fragments, called matricryptins, are released from the extracellular proteins by limited proteolysis and have biological activities on their own. They regulate numerous physiological and pathological processes such as angiogenesis, cancer, diabetes, wound healing, fibrosis and infectious diseases and either improve or worsen the course of diseases depending on the matricryptins and on the molecular and biological contexts. Several protease families release matricryptins from core-matrisome and matrisome-associated proteins both in vitro and in vivo. The major proteases, which decrypt the extracellular matrix, are zinc metalloproteinases of the metzincin superfamily (matrixins, adamalysins and astacins), cysteine proteinases and serine proteases. Some matricryptins act as enzyme inhibitors, further connecting protease and matricryptin fates and providing intricate regulation of major physiopathological processes such as angiogenesis and tumorigenesis. They strengthen the role of the extracellular matrix as a key player in tissue failure and core-matrisome and matrisome-associated proteins as important therapeutic targets.

The response of matrix metalloproteinase-9 and -2 to exercise

BACKGROUND

Matrix metalloproteinases (MMPs) are a major group of enzymes that play essential roles in normal functioning of diverse tissues during growth, development, and aging. However, among the MMPs little is known regarding the role of exercise in MMP-9 and MMP-2 function in humans.

OBJECTIVE

The aim of this study was to provide a systematic comprehensive review of the literature examining the effect of different exercise interventions on MMP-9 and MMP-2 in human investigations.

DATA SOURCES

A comprehensive systematic database search was performed, including PubMed/MEDLINE, Scopus, ScienceDirect, and Web of Science.

STUDY SELECTION

Both the acute and chronic effects of exercise were included for evaluation in this systematic review. Inclusion criteria included the use of any type of planned, structured, and repetitive movement and its effects on the MMP-2 and MMP-9 response (obtained from plasma samples), participants (humans only) of any age with or without diseases, sedentary participants and those involved in light, moderate, and vigorous activity, randomized controlled trials (RCTs) and clinical trials (CTs), full text article citations with no restrictions in terms of language, and scored at least 5/11 on the Physiotherapy Evidence Database (PEDro) quality scale.

STUDY APPRAISAL AND SYNTHESIS METHODS

The PEDro scale was used to appraise study quality of RCTs and CTs. Two reviewers independently reviewed the full texts of all potentially relevant articles for eligibility and disagreements were discussed and resolved.

RESULTS

Seven studies met the previously determined quality indicators and were reviewed; three were RCTs and four were CTs. In general, the quality of the studies ranged from 5 to 9 out of a maximum of 11 on the PEDro quality criteria scale. Results revealed that chronic aerobic training induces a decrease in MMP-9 and MMP-2 levels, possibly indicating a cardioprotective effect, while resistance exercise training displayed conflicting results.

CONCLUSION

Alterations in MMP-9 and MMP-2 plasma concentrations may be valuable biomarkers to reflect the influence of exercise on the inflammatory state. Nevertheless, the limited evidence available regarding the effects of exercise on the MMP-9 and MMP-2 response in human participants suggests that further studies are needed to fully define the connection between the role of exercise on the MMP-9 and MMP-2 response.

In vivo monitoring of angiogenesis during tendon repair: a novel MRI-based technique in a rat patellar tendon model

PURPOSE

Recent in vivo studies were able to show the impairing effect of neoangiogenesis in degenerative tendon diseases. Clinical in vivo monitoring of angiogenesis in injured tendons therefore seems to be crucial for an accurate therapeutic approach. The aim of this study was to develop a novel magnetic resonance imaging (MRI)-based technique for observing angiogenesis during tendon healing in vivo.

METHODS

Tendinopathy was induced by an in situ freezing model of rat patellar tendon and monitored after 7, 14, and 28 days. Animals were randomly divided into an imaging and immunohistochemical group. MRI with a 'blood pool' contrast agent was used to determine neoangiogenesis during tendon healing. MRI was compared to histochemical staining and quantification of blood vessels in injured and native tendons.

RESULTS

MRI data revealed a peak in changes in the transverse relaxation rate (ΔR 2*), which is proportional to relative blood volume, 7 days after surgery and decrease until day 28. Histological microvessel density and vascular endothelial growth factor synthesis were also most evident at day 7 and decreased over time.

CONCLUSIONS

The current results are demonstrating a time-dependent correlation between microvessel density and ΔR 2*. Thus, MRI-based evaluation of angiogenesis in the tendon might be a new promising technique for in vivo monitoring of angiogenesis and therapy response in the future.

Resistance exercise increases endothelial progenitor cells and angiogenic factors

INTRODUCTION

Bone marrow-derived endothelial progenitor cells (EPC) are involved in vascular growth and repair. They increase in the circulation after a single bout of aerobic exercise, potentially related to muscle ischemia. Muscular endurance resistance exercise (MERE) bouts also have the potential to induce muscle ischemia if appropriately structured.

PURPOSE

The objective of this study is to determine the influence of a single bout of MERE on circulating EPC and related angiogenic factors.

METHODS

Thirteen trained men age 22.4 ± 0.5 yr (mean ± SEM) performed a bout of MERE consisting of three sets of six exercises at participants' 15-repetition maximum without resting between repetitions or exercises. The MERE bout duration was 12.1 ± 0.6 min. Blood lactate and HR were 11.9 ± 0.9 mmol·L and 142 ± 5 bpm, respectively, at the end of MERE. Blood was sampled preexercise and at 10 min, 2 h, and 24 h postexercise.

RESULTS

Circulating EPC and serum concentrations of vascular endothelial growth factors (VEGF-A, VEGF-C, and VEGF-D), granulocyte colony stimulating factor, soluble Tie-2, soluble fms-like tyrosine kinase-1, and matrix metalloproteinases (MMP-1, MMP-2, MMP-3, MMP-9, and MMP-9) were higher (P < 0.05) in the postexercise period. Circulating EPC levels were unchanged at 10 min postexercise but higher at 2 h postexercise (P < 0.05). The concentration of most angiogenic factors and metalloproteinases were higher at 10 min postexercise (VEGF-A, +38%; VEGF-C, +40%; VEGF-D, +9%; soluble Tie-2, +15%; soluble fms-like tyrosine kinase-1, +24%; MMP-1, +62%; MMP-2, +3%; MMP-3, +54%; and MMP-9, +45%; all P < 0.05). Soluble E-selectin was lower (P < 0.05) at 2 and 24 h postexercise, with endothelial microparticles and thrombomodulin unchanged.

CONCLUSIONS

Short intense bouts of MERE can trigger increases in circulating EPC and related angiogenic factors, potentially contributing to vascular adaptation and vasculoprotection.

Effects of high intensity training and high volume training on endothelial microparticles and angiogenic growth factors

Aims

Endothelial microparticles (EMP) are complex vesicular structures shed from activated or apoptotic endothelial cells. As endurance exercise affects the endothelium, the objective of the study was to examine levels of EMP and angiogenic growth factors following different endurance exercise protocols.

Methods

12 subjects performed 3 different endurance exercise protocols: 1. High volume training (HVT; 130 min at 55% peak power output (PPO); 2. 4×4 min at 95% PPO; 3. 4×30 sec all-out. EMPs were quantified using flow cytometry after staining platelet-poor-plasma. Events positive for Annexin-V and CD31, and negative for CD42b, were classified as EMPs. Vascular endothelial growth factor (VEGF), migratory inhibiting factor (MIF) and hepatocyte growth factor (HGF) were determined by ELISA technique. For all these measurements venous blood samples were taken pre, 0′, 30′, 60′ and 180′ after each intervention. Furthermore, in vitro experiments were performed to explore the effect of collected sera on target endothelial functions and MP uptake capacities.

Results

VEGF and HGF significantly increased after HIT interventions. All three interventions caused a significant decrease in EMP levels post exercise compared to pre values. The sera taken after exercise increased the uptake of EMP in target endothelial cells compared to sera taken under resting conditions, which was shown to be phosphatidylserin-dependent. Increased EMP uptake was associated with an improved protection of target cells against apoptosis. Sera taken prior and after exercise promoted target endothelial cell migration, which was abrogated after inhibition of VEGF.

Conclusion

Physical exercise leads to decreased EMP levels and promotes a phosphatidylserin-dependent uptake of EMP into target endothelial cells, which is associated with a protection of target cells against apoptosis.

Circulating angiogenic biomolecules at rest and in response to upper-limb exercise in individuals with spinal cord injury

OBJECTIVE

Individuals with spinal cord injury (SCI) show structural and functional vascular maladaptations and muscle loss in their lower limbs. Angiogenic biomolecules play important roles in physiological and pathological angiogenesis, and are implicated in the maintenance of muscle mass. This study examined the responses of angiogenic molecules during upper-limb aerobic exercise in patients with SCI and in able-bodied (AB) individuals.

METHODS

Eight SCI patients with thoracic lesions (T6-T12, ASIA A) and eight AB individuals performed an arm-cranking exercise for 30 minutes at 60% of their VO2max. Plasma concentrations of vascular endothelial growth factor (VEGF-A165), VEGF receptor 1 (sVEGFr-1), VEGF receptor 2 (sVEGFr-2), metalloproteinase 2 (MMP-2), and endostatin were measured at rest, after exercise, and at 1.5 and 3.0 hours during recovery.

RESULTS

The two-way analysis of variance showed non-significant main effects of "group" and significant main effects of "time/exercise" for all angiogenic biomolecules examined (P < 0.01-0.001). The arm-cranking exercise significantly increased plasma concentrations of VEGF, sVEGFr-1, sVEGFr-2, MMP-2, and endostatin in both groups (P < 0.001-0.01). The magnitude of the increase was similar in both patients with SCI and AB individuals, as shown by the non-significant group × time interaction for all angiogenic parameters.

CONCLUSIONS

Upper-limb exercise (arm-cranking for 30 minutes at 60% of VO2max) is a sufficient stimulus to trigger a coordinated circulating angiogenic response in patients with SCI. The response of angiogenic molecules to upper-limb aerobic exercise in SCI appears relatively similar to that observed in AB individuals.

Exercise increases serum endostatin levels in female and male patients with diabetes and controls

Background

Type 2 diabetes mellitus (T2DM) is often associated with atherosclerotic changes in coronary vessels, most notably plaques. The angiostatic parameter endostatin is able to inhibit angiogenesis in tissue as well as in plaques and therefore plays an important role in physiological and pathological neovascularisation. The aim of the present study was to investigate sex-specific differences and the influence of exercise on circulating endostatin levels in patients suffering from diabetes, and control subjects.

Methods

In total, 42 T2DM-patients and 45 control subjects were investigated. They underwent a graded physical stress test (ergometry). Serum endostatin levels were measured in venous blood at rest and directly after reaching maximum workload.

Results

Females showed significantly higher endostatin levels at baseline measurements compared to men, independently of their underlying disease. In both female and male T2DM-patients endostatin levels were significantly lower compared to controls. Both groups and sexes showed a significant increase of endostatin after physical stress, whereas the extent of endostatin-increase was between 10.59-15.05%.

Conclusion

Middle-aged healthy female individuals as well as female T2DM-patients showed higher circulating serum endostatin levels compared to males, suggesting a hormonal influence on baseline circulating endostatin amounts. Exercise-induced increase in endostatin is also observable in patients suffering from T2DM. Concerning vascularisation, lower endostatin levels in T2DM might be advantageous. Concerning plaque stability, lower levels might be prejudicial.

Trial registration

Clinical Trial Registration-URL: http://clinicaltrials.gov/ct2/results?term=NCT01165515

Effects of active vs. passive recovery during Wingate-based training on the acute hormonal, metabolic and psychological response

OBJECTIVE

The exercise-induced metabolic stress can be influenced by the mode of recovery and is associated with acute hormonal responses. Therefore, it is hypothesized that active recovery between high intensity intervals reduces the metabolic stimulus and therefore the hormonal response compared to passive recovery.

DESIGN

12 male cyclist/triathletes performed four 30s all-out intervals, either with active (A) or passive (P) recovery between each bout. Human growth hormone (hGH), testosterone and cortisol, vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and macrophage migration inhibitory factor (MIF) were determined pre, 0', 30', 60' and 180' after both interventions. Metabolic stimuli and perturbations were characterized by lactate, blood gas (pH, BE, HCO3(-), PO2, PCO2), and spirometric analysis.

RESULTS

Both interventions caused a transient increase in circulating levels of cortisol, testosterone, testosterone/cortisol-ratio, hGH, VEGF and HGF. Transient differences between A- and P-recovery were found only for testosterone and HGF directly after exercise, despite significant differences in metabolic disturbances (lactate, acid base status).

CONCLUSION

Based on the data of testosterone, hGH and the testosterone/cortisol-ratio, as well as on the data of VEGF and HGF it appears that this kind of exercise protocol may promote anabolic processes and may lead to pro-angiogenic conditions independent of the mode of recovery. However transient differences between A- and P-recovery were shown for testosterone and HGF. In contrast, cortisol and hGH, which are known to be sensitive for metabolic perturbations (e.g. pH) showed no differences. Therefore, it is proposed that if a certain threshold for metabolic perturbations is exceeded, a hormonal response is induced, which does not differ between A- and P-recovery.

Whole-body vibrations do not elevate the angiogenic stimulus when applied during resistance exercise

Knowledge about biological factors involved in exercise-induced angiogenesis is to date still scanty. The present study aimed to investigate the angiogenic stimulus of resistance exercise with and without superimposed whole-body vibrations. Responses to the exercise regimen before and after a 6-week training intervention were investigated in twenty-six healthy male subjects. Serum was collected at the initial and final exercise sessions and circulating levels of matrix metalloproteinases (MMP) -2 and -9, Vascular Endothelial Growth Factor (VEGF) and endostatin were determined via ELISA. Furthermore, we studied the proliferative effect of serum-treated human umbilical vein endothelial cells in vitro via BrdU-incorporation assay. It was found that circulating MMP-2, MMP-9, VEGF and endostatin levels were significantly elevated (P<0.001) from resting levels after both exercise interventions, with higher post-exercise VEGF concentrations in the resistance exercise (RE) group compared to the resistive vibration exercise (RVE) group. Moreover, RE provoked increased endothelial cell proliferation in vitro and higher post-exercise circulating endostatin concentrations after 6 weeks of training. These effects were elusive in the RVE group. The present findings suggest that resistance exercise leads to a transient rise in circulating angiogenic factors and superimposing vibrations to this exercise type might not further trigger a potential signaling of angiogenic stimulation in skeletal muscle.

The involvement of MMP-2 and MMP-9 in heart exercise-related angiogenesis

BACKGROUND

Little is known about the involvement of matrix metalloproteinases (MMPs) in cardiac vascular remodelling induced by exercise. Our aim was to evaluate and localize MMP-2 and MMP-9's activities in relation to capillary proliferation in mouse hearts trained for 15, 30 and 45 days.

METHODS

Sixty-three mice were randomly assigned to 7 groups: four control sedentary groups (C0, C15, C30 and C45) and three groups trained by an endurance protocol (T15, T30 and T45). MMP-2 and MMP-9 were examined with zymography and immunostaining analyses. Capillary proliferation was evaluated counting the number of CD31-positive cells.

RESULTS

Different activity patterns of the latent form of both MMPs were found. Pro-MMP-9 increased after 15 days of training; whereas pro-MMP-2 gradually decreased after 30 and 45 days of training below the control groups. The latter was inversely correlated with capillary growth. MMP-9 was mainly localized in myocardiocytes and less evident in capillaries. Conversely, MMP-2 was more intense in capillary endothelial cells and slightly in myocardiocytes.

CONCLUSIONS

A different spatiotemporal modulation of pro-MMP-2 and pro-MMP-9 activities has been detected in the myocardium during angiogenesis related to the aerobic training. These results can be useful to draw up training protocols for improving the performance of healthy and diseased human hearts.

Temporal response of positive and negative regulators in response to acute and chronic exercise training in mice

Angiogenesis is controlled by a balance between positive and negative angiogenic factors, but temporal protein expression of many key angiogenic regulators in response to exercise are still poorly defined. In C57BL/6 mice, we evaluated the temporal protein expression of several pro-angiogenic and anti-angiogenic factors in response to (1) a single acute bout of exercise and (2) chronic exercise training resulting from 3, 5, 7, 14 and 28 days of voluntary wheel running. Following acute exercise, protein levels of vascular endothelial growth factor-A (VEGF), endostatin and nucleolin were increased at 2-4 h (P < 0.05), whereas matrix metalloproteinase (MMP)-2 was elevated within a 12-24 h window (P < 0.05). Training increased muscle capillarity 11%, 15% and 22% starting with 7, 14 and 28 days of training, respectively (P < 0.01). Basal VEGF and MMP-2 were increased by 31% and 22%, respectively, compared to controls (P < 0.05) after 7 days (7d) training, but decreased to back to baseline after 14d training. After 28d training VEGF fell 49% below baseline control (P < 0.01). Basal muscle expression of thrombospondin 1 (TSP-1) was ∼900% greater in 14d- and 28d-trained mice compared to either 5d- and 7d-trained mice (P < 0.05), and tended to increase by ∼180-258% compared to basal control levels (P < 0.10). The acute responsiveness of VEGF to exercise in untrained mice (i.e. 161% increase, P < 0.001) was lost with capillary adaptation occurring after 7, 14 and 28d training. Taken together, these data support the notion that skeletal muscle angiogenesis is controlled by a balance between positive and negative mitogens, and reveals a complex, highly-coordinated, temporal scheme whereby these factors can differentially influence capillary growth in response to acute versus chronic exercise.

Serum endostatin and risk of mortality in the elderly: findings from 2 community-based cohorts

OBJECTIVE

Experimental data imply that endostatin, a proteolytically cleaved fragment of collagen XVIII, could be involved in the development of cardiovascular disease and cancer. Prospective data concerning the relation between circulating endostatin and mortality are lacking. Accordingly, we aimed to study associations between circulating endostatin and mortality risk.

APPROACH AND RESULTS

Serum endostatin was analyzed in 2 community-based cohorts: the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS; women 50%, n=931; mean age, 70 years; median follow-up, 7.9 years) and the Uppsala Longitudinal Study of Adult Men (ULSAM; n=748; mean age, 77 years; median follow-up, 9.7 years). During follow-up, 90 participants died in PIVUS (1.28/100 person-years at risk), and 417 participants died in ULSAM (6.7/100 person-years at risk). In multivariable Cox regression models adjusted for age and established cardiovascular risk factors, 1 SD higher ln(serum endostatin level) was associated with a hazard ratio of mortality of 1.39 and 95% confidence interval, 1.26 to 1.53, on average in both cohorts. In the ULSAM cohort, serum endostatin was also associated with cardiovascular mortality (177 deaths; hazard ratio per SD of ln[endostatin] 1.45, 95% confidence interval [1.25-1.71]) and cancer mortality (115 deaths; hazard ratio per SD of ln[endostatin] 1.35, 95% confidence interval [1.10-1.66]).

CONCLUSIONS

High serum endostatin was associated with increased mortality risk in 2 independent community-based cohorts of the elderly. Our observational data support the importance of extracellular matrix remodeling in the underlying pathophysiology of cardiovascular disease and cancer.

Physiological responses and perceived exertion during cycling with superimposed electromyostimulation

The goal of the study was to evaluate and to quantify the effects of local electromyostimulation (EMS) during cycling on the cardiorespiratory system, muscle metabolism, and perceived exertion compared with cycling with no EMS. Ten healthy men (age: 24.6 ± 3.2 years, V[Combining Dot Above]O2max: 54.1 ± 6.0 ml·min·kg) performed 3 incremental cycle ergometer step tests, 1 without and 2 with EMS (30 and 85 Hz) until volitional exhaustion. Lactate values and respiratory exchange ratio were significantly higher at intensities ≥75% peak power output (PPO) when EMS was applied. Bicarbonate concentration, base excess (BE), and Pco2 were significantly lower when EMS was applied compared with the control at intensities ≥75% PPO. Saliva cortisol levels increased because of the exercise but were unaffected by EMS. Furthermore, EMS showed greater effects on CK levels 24 hours postexercise than normal cycling did. Rating of perceived exertion was significantly higher at 100% PPO with EMS. No statistical differences were found for heart rate, pH, and Po2 between the tested cycling modes. The main findings of this study are greater metabolic changes (lactate, respiratory exchange ratio, BE, (Equation is included in full-text article.), Pco2) during cycling with EMS compared with normal cycling independent of frequency, mainly visible at higher work rates. Because metabolic alterations are important for the induction of cellular signaling cascades and adaptations, these results lead to the hypothesis that applied EMS stimulations during cycling exercise might be an enhancing stimulus for skeletal muscle metabolism and related adaptations. Thus, superimposed EMS application during cycling could be beneficial to aerobic performance enhancements in athletes and in patients who cannot perform high workloads. However, the higher demand on skeletal muscles involved must be considered.

Influence of intermittent hypoxia interval training on exercise-dependent erythrocyte NOS activation and blood pressure in diabetic patients

NOS-activation in erythrocytes (eryNOS) is impaired in patients suffering from type 2 diabetes. We investigated the effect of physical exercise on eryNOS activation and whether 6 week hypoxia interval training may alter this process. Male patients with diabetes mellitus type 2 (NIDDM, n = 12; age, 61.3 ± 8.4 years; BMI, 29.8 ± 3.7 kg/m2) underwent physical exercise training before and after 6 week hypoxia interval training. Training was conducted 4 times per week for 90 min at 15.4–12.7 Vol% of inspired oxygen. Vital parameters were recorded. Before hypoxia intervention, eryNOS phosphorylation at serine1177decreased significantly during exercise (basal 17.4 ± 12.0 compared with exercise 8.4 ± 9.2 arbitrary grey values (arGV); P < 0.05). After 6 weeks of hypoxia intervention, eryNOS–pSer1177(2.2 ± 2.5 arGV) was significantly lower at baseline. Ergometry showed an increase (7.6 ± 3.0 arGV; P < 0.05) followed by a decrease to almost baseline levels after 30 min (3.8 ± 1.5 arGV). Maximal exercise capacity and O2-uptake ([Formula: see text]  max) increased significantly. The effects were independent from exercise-induced elevation of blood pressure. Exercise-dependent eryNOS phosphorylation at serine1177was increased similar to that described for the endothelium in diabetic patients. EryNOS dysregulation was partially restored after intermittent hypoxia training.

Impaired biomechanical properties correlate with neoangiogenesis as well as VEGF and MMP-3 expression during rat patellar tendon healing

Recent studies reveal an important role of vascular endothelial growth factor (VEGF)-induced angiogenesis in degenerative tendon diseases. The way how VEGF influences mechanical properties of the tendons is not well understood yet. We here hypothesized that tendinopathy results in a hypoxia-mediated stimulation of VEGF and that the mechanical stability of the tendon is impaired in an angiogenic process by VEGF-induced matrix metalloproteinases (MMPs). A modified in situ freezing model of patellar tendon was used to create a tendinopathy. 0, 7, 14, and 28 days post-surgical animals were sacrificed and patellar tendons were dissected for biomechanical and immunohistochemical analysis. Native tendons were used as controls. Immunohistochemical staining revealed a peak in HIF-1α stabilization immediately after surgery. Both VEGF and MMP-3 were increased 7 days after surgery. Angiogenesis was also abundant 7 days after surgery. In contrast, biomechanical stability of the tendon was decreased 7 days after surgery. The current results reveal a time-dependent correlation of HIF-1/VEGF-induced and MMP-3-supported angiogenesis with decreased biomechanical properties during tendon healing. The therapeutical modulation of neoangiogenesis by influencing the level of VEGF and MMP-3 might be a promising target for new approaches in degenerative tendon diseases. 30:1952-1957, 2012.

Exercise training and peripheral arterial disease

Peripheral arterial disease (PAD) is a common vascular disease that reduces blood flow capacity to the legs of patients. PAD leads to exercise intolerance that can progress in severity to greatly limit mobility, and in advanced cases leads to frank ischemia with pain at rest. It is estimated that 12 to 15 million people in the United States are diagnosed with PAD, with a much larger population that is undiagnosed. The presence of PAD predicts a 50% to 1500% increase in morbidity and mortality, depending on severity. Treatment of patients with PAD is limited to modification of cardiovascular disease risk factors, pharmacological intervention, surgery, and exercise therapy. Extended exercise programs that involve walking approximately five times per week, at a significant intensity that requires frequent rest periods, are most significant. Preclinical studies and virtually all clinical trials demonstrate the benefits of exercise therapy, including improved walking tolerance, modified inflammatory/hemostatic markers, enhanced vasoresponsiveness, adaptations within the limb (angiogenesis, arteriogenesis, and mitochondrial synthesis) that enhance oxygen delivery and metabolic responses, potentially delayed progression of the disease, enhanced quality of life indices, and extended longevity. A synthesis is provided as to how these adaptations can develop in the context of our current state of knowledge and events known to be orchestrated by exercise. The benefits are so compelling that exercise prescription should be an essential option presented to patients with PAD in the absence of contraindications. Obviously, selecting for a lifestyle pattern that includes enhanced physical activity prior to the advance of PAD limitations is the most desirable and beneficial.