Optimal H2O2 preconditioning to improve bone marrow mesenchymal stem cells' engraftment in wound healing.

BACKGROUND: The transplantation of bone marrow mesenchymal stem cells (BMSCs) is a promising therapeutic strategy for wound healing. However, the poor migration capacity and low survival rate of transplanted BMSCs in wounds weaken their potential application. OBJECTIVE: To identify the optimal protocol for BMSCs preconditioned with H2O2 and improve the therapeutic efficacy using H2O2-preconditioned BMSCs in wound healing. METHODS: Mouse BMSCs were exposed to various concentrations of H2O2, and the key cellular functional properties were assessed to determine the optimal precondition with H2O2. The H2O2-preconditioned BMSCs were transplanted into mice with full-thickness excisional wounds to evaluate their healing capacity and tissue engraftment. RESULTS: Treatment BMSCs with 50 µM H2O2 for 12 h could significantly enhance their proliferation, migration, and survival by maximizing the upregulation of cyclin D1, SDF-1, and its receptors CXCR4/7 expressions, and activating the PI3K/Akt/mTOR pathway, but inhibiting the expression of p16 and GSK-3ß. Meanwhile, oxidative stress-induced BMSC apoptosis was also significantly attenuated by the same protocol pretreatment with a decreased ratio of Bax/Bcl-2 and cleaved caspase-9/3 expression. Moreover, after the identification of the optimal protocol of H2O2 precondition in vitro, the migration and tissue engraftment of transfused BMSCs with H2O2 preconditioning were dramatically increased into the wound site as compared to the un-preconditioned BMSCs. The increased microvessel density and the speedy closure of the wounds were observed after the transfusion of H2O2-preconditioned BMSCs. CONCLUSIONS: The findings suggested that 50 µM H2O2 pretreated for 12 h is the optimal precondition for the transplantation of BMSCs, which gives a considerable insight that this protocol may be served as a promising candidate for improving the therapeutic potential of BMSCs for wound healing.

Development and validation of a novel predictive score for sepsis risk among trauma patients.

Background: Patients suffering from major trauma often experience complications such as sepsis. The early recognition of patients at high risk of sepsis after trauma is critical for precision therapy. We aimed to derive and validate a novel predictive score for sepsis risk using electronic medical record (EMR) data following trauma. Materials and methods: Clinical and laboratory variables of 684 trauma patients within 24 h after admission were collected, including 411 patients in the training cohort and 273 in the validation cohort. The least absolute shrinkage and selection operator (LASSO) technique was adopted to identify variables contributing to the early prediction of traumatic sepsis. Then, we constructed a traumatic sepsis score (TSS) using a logistic regression model based on the variables selected in the LASSO analysis. Moreover, we evaluated the discrimination and calibration of the TSS using the area under the curve (AUC) and the Hosmer-Lemeshow (H-L) goodness-of-fit test. Results: Based on the LASSO, seven variables (injury severity score, Glasgow Coma Scale, temperature, heart rate, albumin, international normalized ratio, and C-reaction protein) were selected for construction of the TSS. Our results indicated that the incidence of sepsis after trauma increased with an increasing TSS (Ptrend = 7.44 × 10-21 for the training cohort and Ptrend = 1.16 × 10-13 for the validation cohort). The areas under the receiver operating characteristic (ROC) curve of TSS were 0.799 (0.757-0.837) and 0.790 (0.736-0.836) for the training and validation datasets, respectively. The discriminatory power of our model was superior to that of a single variable and the sequential organ failure assessment (SOFA) score (P < 0.001). Moreover, the TSS was well calibrated (P > 0.05). Conclusions: We developed and validated a novel TSS with good discriminatory power and calibration for the prediction of sepsis risk in trauma patients based on the EMR data.

Clinical relevance of single nucleotide polymorphisms in the CXCL1 and CXCL12 genes in patients with major trauma.

BACKGROUND: Genetic backgrounds have been recognized as significant determinants of susceptibility to sepsis. CXC chemokines play a significant role in innate immunity against infectious diseases. Genetic polymorphisms of CXC chemokine genes have been widely studied in inflammatory and infectious diseases but not in sepsis. Thus, we aimed to investigate the clinical relevance of CXC chemokine gene polymorphisms and susceptibility to sepsis in a traumatically injured population. METHODS: Thirteen tag single nucleotide polymorphisms were selected from CXC chemokine genes using a multimarker tagging algorithm in the Tagger software. Three independent cohorts of injured patients (n = 1700) were prospectively recruited. Selected single nucleotide polymorphisms were genotyped using an improved multiplex ligation detection reaction method. Cytokine production in lipopolysaccharide-stimulated whole blood was measured using an enzyme-linked immunosorbent assay. RESULTS: Among the 13 tag single nucleotide polymorphisms, four single nucleotide polymorphisms (rs1429638, rs266087, rs2297630, and rs2839693) were significantly associated with the susceptibility to sepsis, and three (rs3117604, rs1429638, and rs4074) were significantly associated with an increased multiple organ dysfunction score in the derivation cohort. However, only the clinical relevance of rs1429638 and rs266087 was confirmed in the validation cohorts. In addition, rs2297630 was significantly associated with interleukin 6 production. CONCLUSION: The rs1429638 polymorphism in the CXCL1 gene and the rs2297630 polymorphism in the CXCL12 gene were associated with altered susceptibility to sepsis and might be used as important genetic markers to assess the risks of sepsis in trauma patients. LEVEL OF EVIDENCE: Prognostic and epidemiologic study, level II.

LBP rs2232618 polymorphism contributes to risk of sepsis after trauma.

Background: Previous study revealed that rs2232618 polymorphism (Phe436Leu) within LBP gene is a functional variant and associated with susceptibility of sepsis in traumatic patients. Our aim was to confirm the reported association by enlarging the population sample size and perform a meta-analysis to find additional evidence. Methods: Traumatic patients from Southwest (n = 1296) and Southeast (n = 445) of China were enrolled in our study. After genotyping, the relationship between rs2232618 and the risk of sepsis was analyzed. Furthermore, we proceeded with a comprehensive literature search and meta-analysis to determine whether the rs2232618 polymorphism conferred susceptibility to sepsis. Results: Significance correlation was observed between rs2232618 and risk of sepsis in Southwest patients (P = 0.002 for the dominant model, P = 0.006 for the recessive model). The association was confirmed in Southeast cohort (P = 0.005 for the dominant model) and overall combined cohorts (P = 4.5 × 10-4, P = 0.041 for the dominant and recessive model). Multiple logistical regression analyses suggested that rs2232618 polymorphism was related to higher risk of sepsis (OR = 1.77, 95% CI = 1.26-2.48, P = 0.001 in Southwest patients; OR = 2.11, 95% CI = 1.24-3.58, P = 0.006 in Southeast cohort; OR = 1.54, 95% CI = 1.34-2.08, P = 0.006 in overall cohort). Furthermore, meta-analysis of four studies (including the present study) confirmed that rs2232618 within LBP increased the risk of sepsis (OR = 1.75, P < 0.001 for the dominant model; OR = 6.08, P = 0.003 for the recessive model; OR = 2.72, P < 0.001 for the allelic model). Conclusions: The results from our replication study and meta-analysis provided firm evidence that rs2232618T allele significantly increased the risk of sepsis.

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.

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.