Positive results for patients with COVID-19 discharged form hospital in Chongqing, China.

BACKGROUND: Since December 2019, over 80,000 patients with coronavirus disease 2019 (COVID-19) have been confirmed in China. With the increasing number of recovered patients, more attention should be paid to the follow-up of these patients. METHODS: In the study, 576 patients with COVID-19 discharged from hospital in Chongqing, China from January 24, 2020, to March 10, 2020 were evaluated by viral nucleic acid tests for severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) to determine if they could be released from quarantine. Among the 576 patients, 61 patients (10.6%) had positive RT-PCR test results of SARS-CoV-2. We aimed to analyze the demographics, clinical characteristics and treatment of 61 patients. RESULTS: These positive patients were characterized by older age, chronic medical illness and mild conditions. 38 (62.3%) patients who were asymptomatic without abnormalities on chest radiographs were found in the positive with COVID-19. Also, they showed positive results of stool or sputum specimens with negative results of nasal and pharyngeal swab specimens. The median duration of positive result of SARS-CoV-2 was varied from 3 days to 35 days in the patients discharged from hospital with no family member infection. CONCLUSIONS: Multi-site screening of SARS-CoV-2 including nasal and pharyngeal swabs, stool and sputum specimens could be considered to improve the diagnosis, treatment and infection control in patients with COVID-19. Our findings provide the important information and clinical evidence for the improved management of patients recovered from COVID-19.

Scutellarin attenuates human-neutrophil-elastase-induced mucus production by inhibiting the PKC-ERK signaling pathway in vitro and in vivo.

The aim of this study was to investigate the influence of scutellarin on mucus production induced by human neutrophil elastase (HNE) and the possible in vitro and in vivo mechanisms. To this purpose, cells were incubated with saline, scutellarin or gefitinib for 60 min and exposed to 0.1 µM HNE for 24 h. After being pretreated respectively with saline, scutellarin or gefitinib, rats were challenged intratracheally with HNE by means of nebulization for 30 days. The expression of mucin (MUC) 5AC, protein kinase C (PKC), and extracellular signal-regulated kinase 1/2 (ERK1/2) was assessed by ELISA, RT-PCR or Western blotting. The results showed that scutellarin inhibited MUC5AC mRNA and protein expressions induced by HNE in a concentration-dependent manner in vitro. In the in vivo model, scutellarin significantly attenuated MUC5AC mRNA expression and goblet cell hyperplasia in rats treated with HNE for 30 days, as well as decreased the phosporylation of PKC and ERK1/2 compared to the HNE control group. Therefore, our study showed that scutellarin could prevent mucus hypersecretion by inhibiting the PKC-ERK signaling pathway. Inhalation scutellarin may be valuable in the treatment of chronic inflammatory lung disease.

Effects of scutellarin on MUC5AC mucin production induced by human neutrophil elastase or interleukin 13 on airway epithelial cells.

Scutellarin is a flavonoid extracted from a traditional Chinese herb, Erigeron breviscapus. The present study investigated the effect of scutellarin on MUC5AC mucin production and the possible mechanism. Human bronchial epithelial 16 (HBE16) cells were pretreated with scutellarin for 60 min, and then exposed to human neutrophil elastase (HNE) or interleukin (IL)-13 for 12 hr. RT-PCR and ELISA were performed to measure the amount of MUC5AC mucin production. The results showed that scutellarin inhibited MUC5AC expression both in mRNA and protein level induced by HNE in a concentration-dependent manner. However, scutellarin failed to inhibit MUC5AC mucin production induced by IL-13. To investigate the intracellular mechanisms associated with the effect of scutellarin on MUC5AC mucin production, western blotting was carried out to examine the phosphorylation of protein kinase C (PKC), signal transducer and activator of transcription 6 (STAT6) and extracellular signal-regulated kinase 1/2 (ERK1/2). The phosphorylation of PKC and ERK1/2 was attenuated after treatment with scutellarin, whereas STAT6 was not significantly affected. Therefore, it is suggested that scutellarin down-regulates MUC5AC mucin production on HBE16 cells via ERK-dependent and PKC-dependent pathways.

[Molecular mechanism of interleukin-13-induced mucus hypersecretion in rat airway].

OBJECTIVE: To investigate the effect of interleukin-13 (IL-13) on mucus secretion in vivo and the possible mechanism. METHODS: The SD rats were randomly divided into control group, IL-13 group and IL-13 plus SP600125 group. The phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase 1/2 (JNK1/2) and the level of MUC5AC in the lung tissues were examined using Western blotting. RT-PCR was performed to examine the mRNA level of STAT4 and STAT6, and electrophoretic mobility shift assays (EMSA) was used to detect the DNA-binding activities of Forkhead box a2 (FOXA2) and activator protein-1 (AP-1). RESULTS: IL-13 caused a significant increase in MUC5AC and p-JNK1/2 expression, but did not affect the phosphorylation of ERK1/2. The expression of MUC5AC was attenuated after treatment with SP600125. A significant increase in STAT6 was observed in IL-13 group compared with that in the control group, whereas the expression of STAT4 mRNA was not significantly affected. The DNA-binding activity of FOXA2 was down-regulated after IL-13 exposure, which did not affect the DNA-binding activity of AP-1. CONCLUSION: IL-13 down-regulates mucus secretion via STAT6-FOXA2 pathway in vitro.

[Effects of secretary leukocyte protease inhibitor-transfected bone marrow mesenchymal stem cells on airway inflammation and mucus secretion in chronic obstructive pulmonary disease].

OBJECTIVE: To explore the effects of secretary leukocyte protease inhibitor (SLPI)-transfected bone marrow mesenchymal stem cells (BMSCs) transplantation on airway inflammation and mucus secretion in chronic obstructive pulmonary disease (COPD) rats. METHODS: Sixty rats were equally and randomly divided into negative control, COPD model, BMSCs and SLPI-transfected BMSCs groups. The COPD rat model was established in all rats with the exception of the negative control rats by smoking and intratracheal instillation of lipopolysaccharide (LPS). BMSCs with or without transfection of plasmid containing SLPI gene were delivered through caudal vein of rats at 30 days post-induction. The expression of SLPI was examined with Western blot. The levels of interleukin (IL)-8 and tumor necrosis factor (TNF)-α were detected by enzyme-linked immunosorbent assay (ELISA). Goblet cell hyperplasia of lung pathological section was observed on. RESULTS: Compared with the negative control group, the expression of SLPI increased significantly after the administration of SLPI-transfected BMSCs (0.79 ± 0.06 vs 0.24 ± 0.02, P < 0.05). The levels of IL-8 and TNF-α in BMSCs and SLPI-transfected BMSCs group were lower than those in the COPD model group. Compared with the negative control group, the administration of SLPI-transfected BMSCs resulted in a further decrease in IL-8 and TNF-α in bronchoalveolar lavage fluid [(17.6 ± 1.7) vs (36.6 ± 4.0) ng/L, P < 0.05]. SLPI-transfected BMSCs transplantation also significantly attenuated goblet cell hyperplasia in rats (P < 0.05). CONCLUSION: There is a potential role for cell-based SLPI gene therapy in the treatment of COPD.