The bone marrow endothelial progenitor cell response to septic infection

Early increase in the level of endothelial progenitor cells (EPCs) in the systemic circulation occurs in patients with septic infection/sepsis. The significance and underlying mechanisms of this response remain unclear. This study investigated the bone marrow EPC response in adult mice with septic infection induced by intravenous injection (i.v.) of Escherichia coli. For in vitro experiments, sorted marrow stem/progenitor cells (SPCs) including lineage(lin)-stem cell factor receptor (c-kit)+stem cell antigen-1 (Sca-1)-, lin-c-kit+, and lin- cells were cultured with or without lipopolysaccharides (LPSs) and recombinant murine vascular endothelial growth factor (VEGF) in the absence and presence of anti-Sca-1 crosslinking antibodies. In a separate set of experiments, marrow lin-c-kit+ cells from green fluorescence protein (GFP)+ mice, i.v. challenged with heat-inactivated E. coli or saline for 24 h, were subcutaneously implanted in Matrigel plugs for 5 weeks. Marrow lin-c-kit+ cells from Sca-1 knockout (KO) mice challenged with heat-inactivated E. coli for 24 h were cultured in the Matrigel medium for 8 weeks. The marrow pool of EPCs bearing the lin-c-kit+Sca-1+VEGF receptor 2 (VEGFR2)+ (LKS VEGFR2+) and LKS CD133+VEGFR2+ surface markers expanded rapidly following septic infection, which was supported by both proliferative activation and phenotypic conversion of marrow stem/progenitor cells. Increase in marrow EPCs and their reprogramming for enhancing angiogenic activity correlated with cell-marked upregulation of Sca-1 expression. Sca-1 was coupled with Ras-related C3 botulinum toxin substrate 2 (Rac2) in signaling the marrow EPC response. Septic infection caused a substantial increase in plasma levels of IFN-γ, VEGF, G-CSF, and SDF-1. The early increase in circulating EPCs was accompanied by their active homing and incorporation into pulmonary microvasculature. These results demonstrate that the marrow EPC response is a critical component of the host defense system. Sca-1 signaling plays a pivotal role in the regulation of EPC response in mice with septic infection.

Outcomes After Surgery in High-Risk Patients With Early Stage Lung Cancer

BACKGROUND

Patients with early stage lung cancer considered high risk for surgery are increasingly being treated with nonsurgical therapies. However, consensus on the classification of high risk does not exist. We compared clinical outcomes of patients considered to be high risk with those of standard-risk patients, after lung cancer surgery.

METHODS

A total of 490 patients from our institutional Society of Thoracic Surgeons data from 2009 to 2013 underwent resection for clinical stage I lung cancer. High-risk patients were identified by ACOSOG z4032/z4099 criteria: major: forced expiratory volume in 1 second (FEV1) 50% or less or diffusing capacity of lung for carbon monoxide (Dlco) 50% or less; and minor: (two of the following), age 75 years or more, FEV1 51% to 60%, or Dlco 51% to 60%. Demographics, perioperative outcomes, and survival between high-risk and standard-risk patients undergoing lobectomy and sublobar resection were compared. Univariate analysis was performed using the χ(2) test/Fisher's exact test and the t test/Mann-Whitney U test. Survival was studied using a Cox regression model to calculate hazard ratios, and Kaplan-Meier survival curves were drawn.

RESULTS

In all, 180 patients (37%) were classified as high risk. These patients were older than standard-risk patients (70 years versus 65 years, respectively; p < 0.0001) and had worse FEV1 (57% versus 85%, p < 0.0001), and Dlco (47% versus 77%, p < 0.0001). High-risk patients also had more smoking pack-years than standard-risk patients (46 versus 30, p < 0.0001) and a greater incidence of chronic obstructive pulmonary disease (72% versus 32%, p < 0.0001), and were more likely to undergo sublobar resection (32% versus 20%, p = 0.001). Length of stay was longer in the high-risk group (5 versus 4 days, p < 0.0001), but there was no difference in postoperative mortality (2% versus 1%, p = 0.53). Nodal upstaging occurred in 20% of high-risk patients and 21% of standard-risk patients (p = 0.79). Three-year survival was 59% for high-risk patients and 76% for standard-risk patients (p < 0.0001).

CONCLUSIONS

Good clinical outcomes after surgery for early stage lung cancer can be achieved in patients classified as high risk. In our study, surgery led to upstaging in 20% of patients and acceptable 1-, 2-, and 3-year survival as compared with historical rates for nonsurgical therapies. This study suggests that empiric selection criteria may deny patients optimal oncologic therapy.

Anatomic resection to manage donor partial anomalous pulmonary venous return during lung transplantation: a case report and review

INTRODUCTION

Rare vascular malformations are discovered infrequently in donor lungs before implantation into recipients. However, the proper handling of such malformations can influence ischemic time, implantation strategies, and subsequent patient outcomes.

CASE REPORT

We report a simplified method for addressing the technical challenges of anomalous pulmonary venous return in a donor lung before implantation.

CONCLUSIONS

We demonstrate that anatomic resection is a safe and efficient method for managing this rare congenital vascular malformation.

Cigarette Smoke Alters the Hematopoietic Stem Cell Niche

Effects of tobacco smoke on hematologic derangements have received little attention. This study employed a mouse model of cigarette smoke exposure to explore the effects on bone marrow niche function. While lung cancer is the most widely studied consequence of tobacco smoke exposure, other malignancies, including leukemia, are associated with tobacco smoke exposure. Animals received cigarette smoke exposure for 6 h/day, 5 days/week for 9 months. Results reveal that the hematopoietic stem and progenitor cell (HSPC) pool size is reduced by cigarette smoke exposure. We next examined the effect of cigarette smoke exposure on one supporting cell type of the niche, the mesenchymal stromal cells (MSCs). Smoke exposure decreased the number of MSCs. Transplantation of naïve HSPCs into irradiated mice with cigarette smoke exposure yielded fewer numbers of engrafted HSPCs. This result suggests that smoke-exposed mice possess dysfunctional niches, resulting in abnormal hematopoiesis. Co-culture experiments using MSCs isolated from control or cigarette smoke-exposed mice with naïve HSPCs in vitro showed that MSCs from cigarette smoke-exposed mice generated marked expansion of naïve HSPCs. These data show that cigarette smoke exposure decreases in vivo MSC and HSC number and also increases pro-proliferative gene expression by cigarette smoke-exposed MSCs, which may stimulate HSPC expansion. These results of this investigation are clinically relevant to both bone marrow donors with a history of smoking and bone marrow transplant (BMT) recipients with a history of smoking.

Alcohol suppresses the granulopoietic response to pulmonary Streptococcus pneumoniae infection with enhancement of STAT3 signaling

Enhanced granulopoietic activity is crucial for host defense against bacterial pneumonia. Alcohol impairs this response. The underlying mechanisms remain obscure. G-CSF produced by infected lung tissue plays a key role in stimulating bone marrow granulopoiesis. This study investigated the effects of alcohol on G-CSF signaling in the regulation of marrow myeloid progenitor cell proliferation in mice with Streptococcus pneumoniae pneumonia. Chronic alcohol consumption plus acute alcohol intoxication suppressed the increase in blood granulocyte counts following intrapulmonary challenge with S. pneumoniae. This suppression was associated with a significant decrease in bone marrow granulopoietic progenitor cell proliferation. Alcohol treatment significantly enhanced STAT3 phosphorylation in bone marrow cells of animals challenged with S. pneumoniae. In vitro experiments showed that G-CSF-induced activation of STAT3-p27(Kip1) pathway in murine myeloid progenitor cell line 32D-G-CSFR cells was markedly enhanced by alcohol exposure. Alcohol dose dependently inhibited G-CSF-stimulated 32D-G-CSFR cell proliferation. This impairment of myeloid progenitor cell proliferation was not attenuated by inhibition of alcohol metabolism through either the alcohol dehydrogenase pathway or the cytochrome P450 system. These data suggest that alcohol enhances G-CSF-associated STAT3-p27(Kip1) signaling, which impairs granulopoietic progenitor cell proliferation by inducing cell cycling arrest and facilitating their terminal differentiation during the granulopoietic response to pulmonary infection.