Mitotic asynchrony induces transforming growth factor-β1 secretion from airway epithelium

We recently proposed that mitotic asynchrony in repairing tissue may underlie chronic inflammation and fibrosis, where immune cell infiltration is secondary to proinflammatory cross-talk among asynchronously repairing adjacent tissues. Building on our previous finding that mitotic asynchrony is associated with proinflammatory/fibrotic cytokine secretion (e.g., transforming growth factor [TGF]-β1), here we provide evidence supporting cause-and-effect. Under normal conditions, primary airway epithelial basal cell populations undergo mitosis synchronously and do not secrete proinflammatory or profibrotic cytokines. However, when pairs of nonasthmatic cultures were mitotically synchronized at 12 hours off-set and then combined, the mixed cell populations secreted elevated levels of TGF-β1. This shows that mitotic asynchrony is not only associated with but is also causative of TGF-β1 secretion. The secreted cytokines and other mediators from asthmatic cells were not the cause of asynchronous regeneration; synchronously mitotic nonasthmatic epithelia exposed to conditioned media from asthmatic cells did not show changes in mitotic synchrony. We also tested if resynchronization of regenerating asthmatic airway epithelia reduces TGF-β1 secretion and found that pulse-dosed dexamethasone, simvastatin, and aphidicolin were all effective. We therefore propose a new model for chronic inflammatory and fibrotic conditions where an underlying factor is mitotic asynchrony.

Association between sleep quality and physical fitness in female young adults

AIM

Sleep quality and physical fitness are critical for young adults' growth and health. However, no study has examined the association between sleep quality and physical fitness in young adults.

METHODS

A total of 291 female college students (mean age: 19.3+/-0.6 years; mean height: 160.3+/-5.2 cm; mean weight: 52.2+/-9.8 kg), in the northern part of Taiwan, volunteered as subjects. For sleep quality evaluation, a valid Chinese version of the Pittsburgh Sleep Quality Index (PSQI) was used. For physical fitness testing, a battery of field-based health-related fitness tests was conducted by well-trained instructors. Data was analyzed using independent t-tests and the Pearson product-moment correlation coefficient.

RESULTS

Subjects with poor sleep quality (P) (PSQI score >5) were more likely to have lower levels of muscular endurance, flexibility, and cardiovascular fitness. Significant correlations were also found between the global PSQI score and physical fitness performances in female young adults.

CONCLUSION

This study confirmed the high prevalence of P among young adults. Education materials should try to prevent young adults from developing poor sleep patterns and inactive lifestyles. Moreover, subjects with P should take better care of health problems from cardiovascular disease and musculoskeletal injury.