The cellular kinetics of lung alveolar epithelial cells and its relationship with lung tissue repair after acute lung injury.

BACKGROUND: Organ regeneration in mammals is hypothesized to require a functional pool of stem or progenitor cells, but the role of these cells in lung regeneration is unknown. METHODS: Based on the fact that postnatal regeneration of alveolar tissue has been attributed to alveolar epithelial cells, we established a hemorrhagic shock and Lipopolysaccharide (LPS) lung injury model. Using this model, we analyzed the cellular kinetics of lung alveolar epithelial cells. RESULTS: The results showed that alveolar epithelium type 2 cells (AEC2s) are damage resistant during acute lung injury, they might be the main cells involved in lung injury and repair. Then we observed the relationship between the expression of HGF, c-Met following ALI in rat lung and proliferation of AEC2s. The proliferation of AEC2s was inhibited when isolated primary AEC2s were co-cultured with c-Met inhibitor SU11274. Furthermore, the numbers of AEC2s was significantly decreased when ALI rats were administrated with SU11274 in vivo. It provided further evidence that the HGF/c-Met signaling plays a vital role in ALI-induced AEC2s proliferation. CONCLUSIONS: AEC2s are damage resistant during acute lung injury and the HGF/c-Met signaling pathway is of vital importance in the proliferation of AEC2s after ALI.

Isolation of lung multipotent stem cells using a novel microfluidic magnetic activated cell sorting system.

In recent years, more and more research has shown that the lung is an organ of regenerative potential, with several types of stem/progenitor cells undergoing proliferation and differentiation after lung injury and participating the injury repair process. Mouse lung multipotent stem cells (MLSCs) have extensive self-renewal ability in culture and could differentiate into endothelial and lung epithelial (alveolar epithelial type 1, 2, and Clara) cells in vitro. But the research of MLSCs was limited due to its rarity. In this study, we introduced a novel microfluidic magnetic activated cell sorting system in the isolation of MLSCs. The sorted MLSCs had better viability and purity. They were identified by colony formation efficiency and differentiation ability and they have self-renewal and differentiation capacities, highlighting their stem cell properties.

Rs1800625 in the receptor for advanced glycation end products gene predisposes to sepsis and multiple organ dysfunction syndrome in patients with major trauma.

INTRODUCTION: The receptor for advanced glycation end products (RAGE) is a transmembrane receptor of the immunoglobulin superfamily, it plays pivotal roles in the pathogenesis of sepsis in several ways. Our previous study showed that rs1800625 (-429T/C) revealed a strong clinical relevance with sepsis morbidity rate and multiple organ dysfunction syndrome (MODS) in patients with major trauma. In this study, we enlarged the sample size, added two validation populations and examined the expression of RAGE on the surface of peripheral leukocytes to ex vivo lipopolysaccharide (LPS) stimulation in subjects with different genotypes. METHODS: Rs1800625 was genotyped using pyrosequencing in 837 Chinese Han patients with major trauma in Chongqing. We then validated the clinical relevance in 340 Zhejiang and 347 Yunnan patients. The expression of RAGE on the surface of peripheral blood mononuclear cells was measured by flow cytometric analysis. RESULTS: The results indicated that rs1800625 was significantly associated with sepsis morbidity rate and MODS in patients with major trauma in the Chongqing, Zhejiang and Yunnan districts. Patients with CC genotype had lower sepsis morbidity rate and MODS after major trauma. Furthermore, patients with CC genotype had significantly higher RAGE expression (P = 0.009). CONCLUSIONS: The rs1800625 polymorphism is a functional single nucleotide polymorphism and confers host susceptibility to sepsis and MODS in patients with major trauma.

[Treatment of open fracture of lower limb in high altitude area].

OBJECTIVE: To explore the treatment methods and experience of open fracture of lower limb in high altitude area. METHODS: From January 2016 to January 2021, 62 patients with open fractures of lower limbs were treated by staged surgery with the concept of injury control orthopedics, emphasizing wound treatment and combining various fracture fixation methods. There were 51 males and 11 females, ranging in age from 14 to 59 years old, with a mean of (37.2±12.3) years old; and the course of disease ranged from 7 to 59 days, with a mean of (23.7±15.5) days. According to Gustilo Anderson classification, there were 14 cases of typeⅠ, 24 cases of typeⅡ, 14 cases of typeⅢA, 8 cases of typeⅢB and 2 cases of typeⅢC. The fracture repair and wound healing were observed, and the clinical efficacy was evaluated by Johner-Wruhs evaluation standard. RESULTS: Fifty-five patients were followed up, and the duration ranged from 4 to 36 months, with a mean of (14.7±8.5) months, and 7 cases were lost to follow-up. According to Johner-Wruhs evaluation criteria, 33 cases got an excellent result, 16 good, 4 poor and 2 bad. The wound healing was poor in 2 cases, partial necrosis of Achilles tendon in 1 case, nonunion of fracture in 1 case and delayed healing of fracture in 2 cases. CONCLUSION: It is an effective method to treat the open fracture of lower extremity in high altitude area to pay attention to the management of soft tissue injury, the management of wound moisturizing, staged operation of fracture and full protection of blood supply at the fracture end. Paying attention to the treatment of soft tissue injury and the management of wound moisturizing, staged operation of fracture and full protection of blood supply at the fracture end are effective methods for the treatment of open fracture of lower limbs in high altitude areas.