Prevalence of interstitial lung disease in polymyositis and dermatomyositis: A meta-analysis from 2000 to 2020.

OBJECTIVE: Interstitial lung disease (ILD) is the most important prognostic factor for mortality in patients with polymyositis (PM) and dermatomyositis (DM), but the prevalence of ILD in PM/DM may vary between countries. The aim of this study was to determine the overall prevalence of ILD in global patients with PM/DM. METHODS: We performed a systematic literature review of studies published from Jan 1, 2000 to April 30, 2020 on ILD and PM/DM. We extracted data and pooled the prevalence by using a random-effect model due to high heterogeneity. Heterogeneity was assessed by subgroup analysis and sensitivity analysis. RESULTS: A total of 34 studies with 10,130 patients were included in our meta-analysis. Pooled data demonstrated that the global prevalence of ILD in patients with PM/DM was 0.41 (95% confidence interval [CI] 0.35-0.48). However, this prevalence varied with geographical locations and time trends. The prevalence of ILD in PM/DM was 0.5 (95% CI 0.42-0.57) in Asia, 0.23 (95% CI 0.15-0.31) in America, and 0.26 (95% CI 0.18-0.34) in Europe. A higher prevalence of ILD was reported in studies published in 2011-2015 (0.43, 95% CI 0.34-0.52) and 2016-2020 (0.45, 95% CI 0.35-0.54), compared with those published in 2000-2010 (0.27, 95% CI 0.16-0.39). The pooled prevalence of ILD in patients with DM, PM, and clinically amyopathic dermatomyositis subtype was 0.42 (95% CI 0.35-0.49), 0.35 (95% CI 0.27-0.42), and 0.53 (95% CI 0.32-0.74), respectively. Patients with anti-Jo-1 and anti-melanoma differentiation-associated gene 5 antibodies were more likely to develop ILD than other myositis-specific autoantibodies. CONCLUSION: The global prevalence of ILD in patients with PM/DM was approximately 41% and the condition was predominant in Asians. This highlights potential genetic and environmental differences in the pathogenesis of ILD in patients with PM/DM. More studies are required to elucidate the specific associations.

Effects of 5-hydroxytryptamine and 5-hydroxytryptamine 2A/2C agonist on the genioglossus activity and sleep apnea in rats.

BACKGROUND: 5-Hydroxytryptamine (5-HT) is a common neurotransmitter in the brain which plays an important role in the pathogenesis of sleep apnea. Dysfunction of 5-HT and 5-HT(2) receptors may lead to the collapse of the upper airway and the instability of respiratory control, which in turn produce apnea. Genioglossus (GG) is one of the most important oropharyngeal muscles maintaining the upper airway open. The present study aimed to investigate the effects of 5-HT and 5-HT(2) receptor on GG activity and the sleep apnea in Sprague-Dawley (SD) rats. METHODS: Microinjection probes were placed within the fourth ventricle of sixteen SD rats. After recovery for a week, the electromyogram (EMG) of GG was recorded in the anesthetized and vagotomized rats. The changes of GG activity before and after the microinjection of 5-HT or 5-HT(2A/2C) agonist -2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI) were observed. Probes were also laid in another eight SD rats. Electroencephalogram (EEG), EMG of neck muscle and respiration were recorded at the same time a week later. The effects of DOI on the occurrence of sleep apnea were explored. RESULTS: Both 5-HT and DOI significantly enhanced the activity of GG just 3 minutes after the completion of injection. The effect of 5-HT disappeared quickly and the effect of DOI lasted for more than 27 minutes. DOI also significantly decreased the post-sigh apnea index in non-rapid-eye-movement (NREM) and rapid-eye-movement (REM) sleep and decreased the spontaneous apnea index only in NREM sleep (P < 0.05, respectively). CONCLUSION: 5-HT and 5-HT(2A/2C) system correlated closely with the pathogenesis of the sleep apnea syndrome and 5-HT receptors may become the target of the drug treatment.

[Effects of 5-HT2 agonist/antagonist on sleep apnea in Sprague-Dawley rats].

OBJECTIVE: To evaluate the effects of 5-HT2 agonist/antagonist Ketanserin on sleep apnea in Sprague-Dawley (SD) rats. METHODS: Twenty adult male SD rats were operated for implantation of EEG and EMG electrodes and a microinjection probe was placed within the fourth ventricle. After recovery for a week, rats were monitored for sleep and respiration in three continuous days. There is no intervention on the first day. Before monitoring, 40 microl ACSF were microinjected into the IV ventricle of the rats on the second day. On the third day before monitoring, 40 microl DOI were microinjected into the IV ventricle of ten rats and 40 microl Ketanserin into another ten ones. RESULTS: Compared with blank control and microinjection of ACSF, DOI significantly reduced the total apnea index (AI) from 18.3 (11.1, 20.3) times/h and 15.2 (11.4, 18.0) times/h to 10.8 (3.1, 14.1) times/h (P=0.005 and 0.005, respectively). Post sign apnea index (PSAI) during non-rapid eye movement (NREM) and rapid eye movement (REM) sleep as well as spontaneous apnea index (SPAI) during NREM sleep were all significantly decreased; (P<0.05, respectively); while it had no effect on SPAI during REM sleep (P>0.05). Neither sleep efficiency (the percent of total sleep time in total monitoring time) nor the time ratio of NREM sleep and REM sleep was significantly changed. In contrast to blank control and microinjection of ACSF, Ketanserin significantly reduced the total apnea index (AI) from 19.2 (13.7, 20.9) times/h and 19.0 (12.9, 21.6) times/h to 13.1 (9.5, 14.9) times/h (P=0.005 and 0.005, respectively). PSAI during NREM and REM sleep were significantly decreased (P<0.05, respectively). SPAI during NREM and REM sleep were changed without statistically significant (P>0.05, respectively). It also had no effects on sleep efficiency and the time ratio of NREM sleep and REM sleep. CONCLUSION: Both 5-HT2 agonist and antagonist decreased the sleep apnea index and had no effects on sleep structure. It shows that the role of 5-HT2 receptor in the respiratory regulation during sleep is complex. The mechanisms involved remain to be studied in future.