Jun She

KGF‐2 targets alveolar epithelia and capillary endothelia to reduce high altitude pulmonary oedema in rats

High altitude pulmonary oedema (HAPE) severely affects non‐acclimatized individuals and is characterized by alveolar flooding with protein‐ rich oedema as a consequence of blood‐gas barrier disruption. Limited choice for prophylactic treatment warrants effective therapy against HAPE. Keratinocyte growth factor‐2 (KGF‐2) has shown efficiency in preventing alveolar epithelial cell DNA damages in vitro. In the current study, the effects of KGF‐2 intratracheal instillation on mortality, lung liquid balance and lung histology were evaluated in our previously developed rat model of HAPE. We found that pre‐treatment with KGF‐2 (5 mg/kg) significantly decreased mortality, improved oxygenation and reduced lung wet‐to‐dry weight ratio by preventing alveolar‐capillary barrier disruption demonstrated by histological examination and increasing alveolar fluid clearance up to 150%. In addition, KGF‐2 significantly inhibited decrease of transendothelial permeability after exposure to hypoxia, accompanied by a 10‐fold increase of Akt activity and inhibited apoptosis in human pulmonary microvascular endothelial cells, demonstrating attenuated endothelial apoptosis might contribute to reduction of endothelial permeability. These results showed the efficacy of KGF‐2 on inhibition of endothelial cell apoptosis, preservation of alveolar‐capillary barrier integrity and promotion of pulmonary oedema absorption in HAPE. Thus, KGF‐2 may represent a potential drug candidate for the prevention of HAPE.

Bone marrow-derived mesenchymal stem cells enhance autophagy via PI3K/AKT signalling to reduce the severity of ischaemia/reperfusion-induced lung injury

Autophagy, a type II programmed cell death, is essential for cell survival under stress, e.g. lung injury, and bone marrow‐derived mesenchymal stem cells (BM‐MSCs) have great potential for cell therapy. However, the mechanisms underlying the BM‐MSC activation of autophagy to provide a therapeutic effect in ischaemia/reperfusion‐induced lung injury (IRI) remain unclear. Thus, we investigate the activation of autophagy in IRI following transplantation with BM‐MSCs. Seventy mice were pre‐treated with BM‐MSCs before they underwent lung IRI surgery in vivo. Human pulmonary micro‐vascular endothelial cells (HPMVECs) were pre‐conditioned with BM‐MSCs by oxygen‐glucose deprivation/reoxygenation (OGD) in vitro. Expression markers for autophagy and the phosphoinositide 3‐kinase/protein kinase B (PI3K/Akt) signalling pathway were analysed. In IRI‐treated mice, administration of BM‐MSCs significantly attenuated lung injury and inflammation, and increased the level of autophagy. In OGD‐treated HPMVECs, co‐culture with BM‐MSCs attenuated endothelial permeability by decreasing the level of cell death and enhanced autophagic activation. Moreover, administration of BM‐MSCs decreased the level of PI3K class I and p‐Akt while the expression of PI3K class III was increased. Finally, BM‐MSCs‐induced autophagic activity was prevented using the inhibitor LY294002. Administration of BM‐MSCs attenuated lung injury by improving the autophagy level via the PI3K/Akt signalling pathway. These findings provide further understanding of the mechanisms related to BM‐MSCs and will help to develop new cell‐based therapeutic strategies in lung injury.

Keratinocyte growth factor-2 intratracheal instillation significantly attenuates ventilator-induced lung injury in rats.

Preservation or restoration of normal alveolar epithelial barrier function is crucial for pulmonary oedema resolution. Keratinocyte growth factor‐2 (KGF‐2), a potent epithelial cell mitogen, may have a role in preventing ventilator‐induced lung injury (VILI), which occurs frequently in mechanically ventilated patients. The aim of the study was to test the role of KGF‐2 in VILI in rats. Forty healthy adult male Sprague‐Dawley rats were randomly allocated into four groups, where rats in Groups HVZP (high‐volume zero positive end‐expiratory pressure) and HVZP+KGF‐2 were given intratracheally equal PBS and 5 mg/kg KGF‐2 72 hrs before 4 hrs HVZP ventilation (20 ml/kg), respectively, while PBS and KGF‐2 were administered in the same manner in Groups Control and KGF‐2, which underwent tracheotomy only with spontaneous breathing. Inflammatory cytokines (tumour necrosis factor‐α, macrophage inflammatory protein 2), neutrophil and total protein levels in bronchoalveolar lavage fluid and surfactant protein mRNA expression in lung tissue were detected; the number of alveolar type II cells, lung water content and lung morphology were also evaluated. The results indicate that pre‐treatment with KGF‐2 showed dramatic improvement in lung oedema and inflammation compared with HVZP alone, together with increased surfactant protein mRNA and alveolar type II cells. Our results suggest that KGF‐2 might be considered a promising prevention for human VILI or other acute lung injury diseases.

Trends in Subpopulations at High Risk for Lung Cancer.

Introduction: Two‐thirds of patients in the United States with newly diagnosed lung cancer would not meet the current U.S. Preventive Services Task Force (USPSTF) screening criteria, which suggests a need for amendment of the definition of high risk. To provide evidence of additional high‐risk subpopulations and estimated gains and losses from using different criteria for screening eligibility, we conducted a two‐step study using three cohorts. Methods: The two prospective cohorts comprised 5988 patients in whom primary lung cancer was diagnosed between 1997 and 2011 (the hospital cohort) and 850 defined‐community residents (the community cohort); the retrospective cohort consisted of the population of Olmsted County, Minnesota, which was observed for 28 years (1984–2011). Subgroups of patients with lung cancer who might have been identified using additional determinates were estimated and compared between the community and hospital cohorts. The findings were supported by indirect comparative projections of two ratios: benefit to harm and cost to effectiveness. Results: Former cigarette smokers who had a smoking history of 30 or more pack‐years and 15 to 30 quit‐years and were 55 to 80 years old formed the largest subgroup not meeting the current screening criteria; they constituted 12% of the hospital cohort and 17% of community cohort. Using the expanded criteria suggested by our study may add 19% more CT examinations for detecting 16% more cases when compared with the USPSTF criteria. Meanwhile, the increases in false‐positive results, overdiagnosis, and radiation‐related lung cancer deaths are 0.6%, 0.1%, and 4.0%, respectively. Conclusions: Current USPSTF screening criteria exclude many patients who are at high risk for development of lung cancer. Including individuals who are younger than 81 years, have a smoking history of 30 or more pack‐years, and have quit for 15 to 30 years may significantly increase the number of cases of non‐overdiagnosed screen‐detected lung cancer, does not significantly add to the number of false‐positive cases, and saves more lives with an acceptable amount of elevated exposure to radiation and cost.