Dataset Information

Inspiratory muscle training attenuates irradiation-induced diaphragm dysfunction.

ABSTRACT: Because radiotherapy (RT) can induce diaphragm dysfunction, this study investigated the protective effect of inspiratory muscle training (IMT) on RT-induced diaphragm damage in patients with esophageal cancer during concurrent chemoradiotherapy (CCRT) in a preclinical setting, and an animal model was designed to confirm and explore the underlying mechanism. Six subjects who underwent CCRT were randomly enrolled in the control or concurrent-IMT group (n=3 per group). The training intensity was set to 30% maximal effort. The diaphragmatic function and functional exercise capacity were assessed weekly during the course of CCRT. Furthermore, Sprague-Dawley (SD) rats were randomly assigned to receive IMT using the tracheal banding method over a 1-week period (n=6) or the sham group (n=6). After training was completed, 5-Gy RT was applied to the diaphragm. All the rats were sacrificed 24 h following RT, and their diaphragms were removed and examined for contractile function, antioxidant capacity, and oxidative injury. In patients receiving IMT, the diaphragm activation efficiency and fatigability and the functional exercise capacity were improved during the CCRT course. The animals belonging to the training group demonstrated significantly higher peak twitch (P<0.01) and tetanus tension (P<0.001), less fatigue (P=0.04), lower protein carbonyl levels (P<0.01) and higher Cu/Zn-SOD and Mn-SOD mRNA expression levels (both P<0.05) compared with those belonging to the control group. Preclinical human and animal models show that the IMT-conditioned diaphragm exhibits better resistance to off-target irradiation damage, but studies with a larger patient sample size are warranted to confirm the applicability of this concept in clinical practice.

SUBMITTER: Wang LY

PROVIDER: S-EPMC6789230 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Inspiratory muscle training attenuates irradiation-induced diaphragm dysfunction.

Wang Li-Ying LY Yang Pei-Yu PY Chen Yu-Jen YJ Wu Huey-Dong HD Huang Yi-Hsuan YH Hsieh Chen-Hsi CH

American journal of translational research 20190915 9

Because radiotherapy (RT) can induce diaphragm dysfunction, this study investigated the protective effect of inspiratory muscle training (IMT) on RT-induced diaphragm damage in patients with esophageal cancer during concurrent chemoradiotherapy (CCRT) in a preclinical setting, and an animal model was designed to confirm and explore the underlying mechanism. Six subjects who underwent CCRT were randomly enrolled in the control or concurrent-IMT group (n=3 per group). The training intensity was se ...[more]

PMID: 31632532

Similar Datasets

Project description:BackgroundThe effects of different modes of mechanical ventilation in the same ventilatory support level on ventilator-induced diaphragm dysfunction onset were assessed in healthy rabbits.MethodsTwenty New Zealand rabbits were randomly assigned to 4 groups (n = 5 in each group). Group 1: no mechanical ventilation; group 2: controlled mechanical ventilation (CMV) for 24 hours; group 3: assist/control ventilation (A/C) mode for 24 hours; group 4: high-level pressure support ventilation (PSV) mode for 24 hours. Heart rate, mean arterial blood pressure, PH, partial pressure of arterial oxygen/fraction of inspired oxygen and partial pressure of arterial carbon dioxide were monitored and diaphragm electrical activity was analyzed in the 4 groups. Caspase-3 was evaluated by protein analysis and diaphragm ultra structure was assessed by electron microscopy.ResultsThe centroid frequency and the ratio of high frequency to low frequency were significantly reduced in the CMV, A/C and PSV groups (P < 0.001). The percent change in centroid frequency was significantly lower in the PSV group than in the CMV and A/C groups (P = 0.001 and P = 0.028, respectively). Electromyography of diaphragm integral amplitude decreased by 90% ± 1.48%, 67.8% ± 3.13% and 70.2% ± 4.72% in the CMV, A/C and PSV groups, respectively (P < 0.001). Caspase-3 protein activation was attenuated in the PSV group compared with the CMV and A/C groups (P = 0.035 and P = 0.033, respectively). Irregular swelling of mitochondria along with fractured and fuzzy cristae was observed in the CMV group, whereas mitochondrial cristae were dense and rich in the PSV group. The mitochondrial injury scores (Flameng scores) in the PSV group were the lowest among the 3 ventilatory groups (0.93 ± 0.09 in PSV versus 2.69 ± 0.05 in the CMV [P < 0.01] and PSV versus A/C groups [2.02 ± 0.08, P < 0.01]).ConclusionsThe diaphragm myoelectric activity was reduced in the PSV group, although excessive oxidative stress and ultra-structural changes of diaphragm were found. However, partial diaphragm electrical activity was retained and diaphragm injury was minimized using the PSV mode.

Project description:IntroductionInspiratory muscle training (IMT) protocols are typically performed using pressure threshold loading with inspirations initiated from residual volume (RV). We aimed to compare effects of three different IMT protocols on maximal inspiratory pressures (PImax) and maximal inspiratory flow (V̇Imax) at three different lung volumes. We hypothesized that threshold loading performed from functional residual capacity (FRC) or tapered flow resistive loading (initiated from RV) would improve inspiratory muscle function over a larger range of lung volumes in comparison with the standard protocol.Methods48 healthy volunteers (42% male, age: 48 ± 9 years, PImax: 110 ± 28%pred, [mean ± SD]) were randomly assigned to perform three daily IMT sessions of pressure threshold loading (either initiated from RV or from FRC) or tapered flow resistive loading (initiated from RV) for 4 weeks. Sessions consisted of 30 breaths against the highest tolerable load. Before and after the training period, PImax was measured at RV, FRC, and midway between FRC and total lung capacity (1/2 IC). V̇Imax was measured at the same lung volumes against a range of external threshold loads.ResultsWhile PImax increased significantly at RV and at FRC in the group performing the standard training protocol (pressure threshold loading from RV), it increased significantly at all lung volumes in the two other training groups (all p < 0.05). No significant changes in V̇Imax were observed in the group performing the standard protocol. Increases of V̇Imax were significantly larger at all lung volumes after tapered flow resistive loading, and at higher lung volumes (i.e., FRC and 1/2 IC) after pressure threshold loading from FRC in comparison with the standard protocol (all p < 0.05).ConclusionOnly training with tapered flow resistive loading and pressure threshold loading from functional residual capacity resulted in consistent improvements in respiratory muscle function at higher lung volumes, whereas improvements after the standard protocol (pressure threshold loading from residual volume) were restricted to gains in PImax at lower lung volumes. Further research is warranted to investigate whether these results can be confirmed in larger samples of both healthy subjects and patients.

Project description:BackgroundLittle is known about the response of the equine respiratory muscles to training.ObjectivesTo measure an index of inspiratory muscle strength (IMSi) before and after a period of conventional exercise training (phase 1) and inspiratory muscle training (IMT), comparing high-load (treatment) and low-load (control) groups (phase 2).Study designProspective randomised controlled trial.MethodsPhase 1: Twenty National Hunt Thoroughbred racehorses performed an inspiratory muscle strength test (IMST) twice on two occasions; when unfit at timepoint A (July), and when race fit at timepoint B (October). Phase 2: Thirty-five Thoroughbred racehorses at race fitness were randomly assigned into a high-load (treatment, n = 20) or low-load (control, n = 15) IMT group. The high-load group followed an IMT protocol that gradually increased the inspiratory pressure applied every 4 days. The low-load group underwent sham IMT with a low training load. The IMT was performed 5 days/week for 10 weeks. The IMST was performed twice on two occasions, timepoint B (October) and timepoint C (January). Conventional exercise training and racing continued during the study period. The peak IMSi values obtained from the different groups at timepoints A, B and C were compared using a Wilcoxon Signed Rank Test.ResultsPhase 1: There was a significant increase in IMSi from timepoint A: 22.5 cmH2 O (21-25) to timepoint B: 26 cmH2 O (24-30) (p = 0.015). Phase 2: From timepoint B to C there was a significant increase in IMSi for the high-load group 34 cmH2 O (28-36) (p = 0.001) but not the low-load group 26 cmH2 O (24-30) (p = 0.929). The peak IMSi at timepoint C was significantly higher for the high-load than low-load group (p = 0.019).Main limitationsSingle centre study with only National Hunt horses undergoing race-training included.ConclusionsIn horses undergoing race training there is a significant increase in IMSi in response to conventional exercise training and high-load IMT.

Dataset Information

Inspiratory muscle training attenuates irradiation-induced diaphragm dysfunction.

Publications

Inspiratory muscle training attenuates irradiation-induced diaphragm dysfunction.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets