Assessing the causal role of physical activity and leisure sedentary behaviours with chronic obstructive pulmonary disease: a Mendelian randomisation study.

BACKGROUND: Observational studies show that patients with chronic obstructive pulmonary disease (COPD) tend to be sedentary during leisure time. Physical activity (PA) may reduce the risk of COPD, but the causal relationship is unclear. We used a Mendelian randomisation (MR) method to elucidate the association of leisure sedentary behaviours (LSB) and PA with lung function and COPD. METHODS: Data on LSB (n=422 218), PA (n=608 595), COPD (n=299 929) and lung function (n=79 055) were obtained from the large-scale genome-wide association study. Causal inference used inverse variance-weighted, MR-Egger and weighted median. Sensitivity analysis was performed to assess heterogeneity and pleiotropy, and radial MR was used to distinguish outliers. The primary outcome was analysed by multifactorial MR adjusted for daily smoking. RESULTS: The inverse variance weighted analysis indicated that increased moderate-to-vigorous PA (MVPA) is associated with higher levels of forced vital capacity (FVC) (beta=0.27, 95% CI 0.12 to 0.42; p=3.51×10-4). For each increment of 2.8 hours in television watching, the odds of COPD were 2.25 times greater (OR=2.25; 95% CI 1.84 to 2.75; p=2.38×10-15). For early-onset COPD, the odds were 2.11 times greater (OR=2.11; 95% CI 1.56 to 2.85; p=1.06×10-6), and for late-onset COPD, the odds were 2.16 times greater (OR=2.16; 95% CI 1.64 to 2.84; p=3.12×10-8). Similarly, the odds of hospitalisation for COPD were 2.02 times greater with increased television watching (OR=2.02; 95% CI 1.59 to 2.55; p=4.68×10-9). Television watching was associated with lower FVC (beta=-0.19, 95% CI -0.28 to -0.10; p=1.54×10-5) and forced expiratory volume in the 1 s (FEV1) (beta=-0.16, 95% CI -0.25 to -0.08; p=1.21×10-4) levels. The results remained significant after adjustment for smoking. CONCLUSIONS: Our study suggests a potential association with LSB, particularly television watching, is associated with higher odds of COPD and lower indices of lung function as measured continuously, including FEV1 and FVC. Conversely, an increase in MVPA is associated with higher indices of lung function, particularly reflected in increased FVC levels.

Preparation and physicochemical characterization of T-OA PLGA microspheres.

As the carrier of water-insoluble drugs, microspheres can play a role in increasing solubility and delaying releasing essence. The objective of this study was to improve the solubility and to delay the release of a newly discovered antitumor compound 3ß-hydroxyolea-12-en-28-oic acid-3, 5, 6-trimethylpyrazin-2-methyl ester (T-OA). Early-stage preparation discovery concept (EPDC) was employed in the present study. The preparation, physicochemical characterization, and drug release properties of PLGA microspheres were evaluated. T-OA-loaded PLGA microspheres were prepared by an oil-in-water (O/W) emulsification solvent evaporation method. Characterization and release behaviors of the T-OA PLGA microspheres were evaluated by X-ray diffract (XRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and high performance liquid chromatography (HPLC). The results demonstrated that T-OA-loaded PLGA microspheres could be successfully obtained through solvent evaporation method with appropriate morphologic characteristics and high encapsulation efficiency. The XRD analysis showed that T-OA would be either molecularly dispersed in the polymer or distributed in an amorphous form. The DSC and FTIR analysis proved that there were interactions between T-OA and PLGA polymer. SEM observations displayed the morphology of the microspheres was homogeneous and the majority of the spheres ranged between 50 and 150 µm. The drug release behavior of the microspheres in the phosphate buffered saline medium exhibited a sustained release and the duration of the release lasted for more than 23 days, which was fit with zero-order release pattern with r2 = 0.9947. In conclusion, TOA-loaded PLGA microspheres might hold great promise for using as a drug-delivery system in biomedical applications.