Effects of the common polymorphism in the human aldehyde dehydrogenase 2 (ALDH2) gene on the lung.

BACKGROUND: Aldehyde dehydrogenases (ALDHs) play a major role in detoxification of aldehydes. High expression of ALDHs is a marker for stem cells of many organs including the lungs. A common polymorphism in ALDH2 gene (ALDH2*2) results in inactivation of the enzyme and is associated with alcohol flushing syndrome and increased risk for cardiovascular and Alzheimer's diseases and some cancers. The effect of this ALDH2 polymorphism on the lung and its stem cells has not been thoroughly examined. METHODS: We examined the association between the ALDH2*2 allele and lung function parameters in a population of healthy individuals. We also examined its association with the incidence of asthma and COPD in patient cohorts. We used the in vitro colony forming assay to detect the effect of the polymorphism on lung epithelial stem cells from both primary human surgical samples and Aldh2*2 transgenic (Tg) and Aldh2 -/- mice. Response to acute and chronic lung injuries was compared between wild type (WT), Aldh2*2 Tg and Aldh2 -/- mice. RESULTS: In humans, the ALDH2*2 allele was associated with lower FEV1/FVC in the general population, but not with the development of asthma or COPD. Both the bronchial and lung epithelium carrying the ALDH2*2 allele showed a tendency for lower colony forming efficiency (CFE) compared to ALDH2 allele. In mice, the tracheal epithelial thickness, nuclear density, and number of basal stem cells were significantly lower in Aldh2 -/- and Aldh2*2 Tg adult mice than in WT. Electron microscopy showed significantly increased number of morphologically abnormal mitochondria in the trachea of Aldh2 -/- mice. Aldh2 -/- tracheal and lung cells showed higher ROS levels and fewer functional mitochondria than those from WT mice. No significant differences were detected when tracheal and lung epithelial stem cells were examined for their in vitro CFE. When exposed to chronic cigarette smoke, Aldh2*2 Tg mice were resistant to emphysema development, whereas influenza infection caused more epithelial damage in Aldh2 -/- mice than in WT mice. CONCLUSIONS: ALDH2 polymorphism has several subtle effects on the lungs, some of which are similar to changes observed during normal aging, suggesting a "premature lung aging" effect.

Observation on the functional characteristics of multidrug-resistant Mycobacterium tuberculosis-infected macrophage model / 中华微生物学和免疫学杂志

Objective:To observe the characteristics of the phagocytosis and bactericidal function of multidrug-resistant Mycobacterium tuberculosis(MDR- Mtb)-infected macrophage model, and the changes of the immune response and metabolic function in the process of phagocytosis and bactericidal function, aiming to provide reference for studying the role and mechanism of macrophages in the occurrence and development of multidrug-resistant tuberculosis(MDR-TB). Methods:We established MDR- Mtb and H37Rv-infected macrophage models, and used the colony-forming unit (CFU), Magnetic Luminex ? Assay and Cholesterol Assay kit to observe the effects on phagocytosis and bactericidal function, the secretion of Th1(IL-12/23 p40, IL-27 and TNF-α) and Th2 cytokines (IL-6 and IL-10) and cholesterol metabolism. The data were analyzed by SPSS25.0 software. The data were expressed as Mean± SD and analyzed by t test or F test. P<0.05 was considered statistically significant. Results:(1) After MDR- Mtb-infected macrophages, the intracellular CFU gradually increased and reached the highest at 24 h, while the extracellular CFU gradually decreased and reached the lowest at 24 h. The intracellular CFU at 48 h was lower than that at 24 h, while the extracellular CFU was higher than that at 24 h ( P<0.05). Both intracellular and extracellular CFU at 48 h were close to those at 4 h ( P>0.05). The intracellular CFU was lower than the H37Rv group at 8-48 h, while the extracellular CFU was higher than the H37Rv group ( P<0.05). (2) The level of IL-12/23 p40, IL-27, TNF-α, IL-6 and IL-10 of MDR-TB group were higher than those of blank group ( P<0.05), but the level of TNF-α and IL-6 at 24 h and 48 h were higher than that at 4 h ( P<0.05). IL-12/23 p40 and TNF-α at 48 h and IL-6 at 24 h were lower than those of the H37Rv group, while IL-27 at 48 h was higher than that of the H37Rv group ( P<0.05). (3) The levels of cholesterol of MDR-TB group at 24 h and 48 h were lower than those of 4 h and blank group ( P<0.05), but the level of cholesterol was similar to the H37Rv group at any time ( P>0.05). (4) TNF-α reached the highest when the intracellular CFU reached the highest at 24 h, and IL-6 reached the highest when the intracellular CFU decreased at 48 h. With the decreasing of cholesterol expression, the intracellular CFU increased and then decreased. Conclusions:MDR- Mtb could induce the phagocytosis and bactericidal function of macrophages, increase the expression of Th1 and Th2 cytokines and promote the utilization and consumption of cholesterol, but this function was weaker than that of H37Rv strain.

Tuberculosis outbreaks in schools: Experiences from the Western Pacific Region

@#Reports of tuberculosis (TB) outbreaks among schoolchildren have increased in recent years in countries across the Western Pacific Region. Cases from China, Japan, Mongolia and the Republic of Korea were studied to derive lessons from the challenges and responses to TB outbreaks in schools. Despite differences in the TB burden and outbreak preparedness, the four countries reported similar challenges. These included delayed diagnosis of index cases, lack of experienced health professionals and sustained financial support, and difficulty in responding to intensified media and community attention. Early detection of outbreaks, established resource mobilization networks, coordination among stakeholders and proactive communication were highlights of successful outbreak responses. These principles could be adapted to each context for responses to future TB outbreaks in schools.