A randomized, crossover, placebo controlled, double blind trial of the effects of tiotropium-olodaterol on neuromuscular performance during exercise in COPD

Expression of intramuscular extracellular matrix proteins in vastus lateralis muscle fibres between atrophic and non-atrophic COPD

Background

Extracellular matrix (ECM) proteins are the major constituents of the muscle cell micro-environment, imparting instructive signalling, steering cell behaviour and controlling muscle regeneration. ECM remodelling is among the most affected signalling pathways in COPD and aged muscle. As a fraction of COPD patients present muscle atrophy, we questioned whether ECM composition would be altered in patients with peripheral muscle wasting (atrophic COPD) compared to those without muscle wasting (non-atrophic COPD).

Methods

A set of ECM molecules with known impact on myogenesis were quantified in vastus lateralis muscle biopsies from 29 COPD patients (forced expiratory volume in 1 s 55±12% predicted) using ELISA and real-time PCR. COPD patients were grouped to atrophic or non-atrophic based on fat-free mass index (<17 or ≥17 kg·m-2).

Results

Atrophic COPD patients presented a lower average vastus lateralis muscle fibre cross-sectional area (3872±258 μm2) compared to non-atrophic COPD (4509±198 μm2). Gene expression of ECM molecules was found significantly lower in atrophic COPD compared to non-atrophic COPD for collagen type I alpha 1 chain (COL1A1), fibronectin (FN1), tenascin C (TNC) and biglycan (BGN). In terms of protein levels, there were no significant differences between the two COPD cohorts for any of the ECM molecules tested.

Conclusions

Although atrophic COPD presented decreased contractile muscle tissue, the differences in ECM mRNA expression between atrophic and non-atrophic COPD were not translated at the protein level, potentially indicating an accumulation of long-lived ECM proteins and dysregulated proteostasis, as is typically observed during deconditioning and ageing.

Efficacy and safety of long-term use of a positive expiratory pressure device in chronic obstructive pulmonary disease patients, a randomized controlled trial

BACKGROUND

Exercise intolerance is among the most common symptoms experienced by patients with chronic obstructive pulmonary disease (COPD), which is associated with lung dynamic hyperinflation (DH). There was evidence that positive expiratory pressure (PEP), which could be offered by less costly devices, could reduce DH. The purpose of this study was to evaluate the efficacy and safety of long-term domiciliary use of PEP device in subjects with COPD.

METHODS

A randomized controlled trial was conducted and 25 Pre-COPD or mild-to-very severe subjects with COPD were randomized to intervention group (PEP device, PEP = 5 cmH₂O, n = 13) and control group (Sham-PEP device, PEP = 0 cmH₂O, n = 12). PEP device was a spring-loaded resistor face mask. Subjects were treated 4 h per day for a total of 2 months. Six-minute walk test (6MWT), pulmonary function, the Modified British Medical Research Council score, and partial pressure of end-tidal carbon dioxide were evaluated at baseline and after two months.

RESULTS

The 6MWD (- 71.67 ± 8.70 m, P < 0.001), end-dyspnea (P = 0.002), and end-fatigue (P = 0.022) improved significantly in the intervention group when compared with the control group. All subjects in the intervention group reported that 4 h of daily use of the PEP device was well tolerated and accepted and there were no adverse events.

CONCLUSION

Regular daily use of PEP device is safe and may improve exercise capacity in subjects with COPD or pre-COPD. PEP device could be used as an add-on to pulmonary rehabilitation programs due to its efficacy, safety, and low cost.

TRIAL REGISTRATION

The study was prospectively registered on ClinicalTrials.gov (NCT04742114).