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.

Nonclinical Factors Associated with 30-Day Mortality after Lung Cancer Resection: An Analysis of 215,000 Patients Using the National Cancer Data Base.

BACKGROUND: Clinical variables associated with 30-day mortality after lung cancer surgery are well known. However, the effects of nonclinical factors, including insurance coverage, household income, education, type of treatment center, and area of residence, on short-term survival are less appreciated. We studied the National Cancer Data Base, a joint endeavor of the Commission on Cancer of the American College of Surgeons and the American Cancer Society, to identify disparities in 30-day mortality after lung cancer resection based on these nonclinical factors. STUDY DESIGN: We performed a retrospective cohort analysis of patients undergoing lung cancer resection from 2003 to 2011 using the National Cancer Data Base. Data were analyzed using a multivariable logistic regression model to identify risk factors for 30-day mortality. RESULTS: During our study period, 215,645 patients underwent lung cancer resection. We found that clinical variables, such as age, sex, comorbidity, cancer stage, preoperative radiation, extent of resection, positive surgical margins, and tumor size were associated with 30-day mortality after resection. Nonclinical factors, including living in lower-income neighborhoods with a lesser proportion of high school graduates, and receiving cancer care at a nonacademic medical center were also independently associated with increased 30-day postoperative mortality. CONCLUSIONS: This study represents the largest analysis of 30-day mortality for lung cancer resection to date from a generalizable national cohort. Our results demonstrate that, in addition to known clinical risk factors, several nonclinical factors are associated with increased 30-day mortality after lung cancer resection. These disparities require additional investigation to improve lung cancer patient outcomes.

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.

Toll-like receptor 4/stem cell antigen 1 signaling promotes hematopoietic precursor cell commitment to granulocyte development during the granulopoietic response to Escherichia coli bacteremia.

In response to severe bacterial infection, bone marrow hematopoietic activity shifts toward promoting granulopoiesis. The underlying cell signaling mechanisms remain obscure. To study the role of Toll-like receptor 4 (TLR4)/stem cell antigen-1 (Sca-1) signaling in this process, bacteremia was induced in mice by intravenous injection of Escherichia coli. A subgroup of animals also received intravenous 5-bromo-2-deoxyuridine (BrdU). In a separate set of experiments, bone marrow lineage-negative (lin(-)) stem cell growth factor receptor-positive (c-kit(+)) Sca-1(-) cells containing primarily common myeloid progenitors were cultured in vitro without or with E. coli lipopolysaccharide (LPS). In genotypic background control mice, bacteremia significantly upregulated Sca-1 expression by lin(-) c-kit(+) cells, as reflected by a marked increase in BrdU-negative lin(-) c-kit(+) Sca-1(+) cells in the bone marrow. In mice with the TLR4 gene deletion, this bacteremia-evoked Sca-1 response was blocked. In vitro, LPS induced a dose-dependent increase in Sca-1 expression by cultured marrow lin(-) c-kit(+) Sca-1(-) cells. LPS-induced upregulation of Sca-1 expression was regulated at the transcriptional level. Inhibition of c-Jun N-terminal kinase/stress-activated protein kinase (JNK) activity with the specific inhibitor SP600125 suppressed LPS-induced upregulation of Sca-1 expression by marrow lin(-) c-kit(+) Sca-1(-) cells. Engagement of Sca-1 with anti-Sca-1 antibodies enhanced the expression of Sfpi1 spleen focus-forming virus (SFFV) proviral integration 1 (PU.1) in marrow lin(-) c-kit(+) Sca-1(-) cells cultured with LPS. Sca-1 null mice failed to maintain the marrow pool of granulopoietic cells following bacteremia. These results demonstrate that TLR4/Sca-1 signaling plays an important role in the regulation of hematopoietic precursor cell programming and their enhancement of granulocyte lineage commitment in response to E. coli bacteremia.

Suppression of the stem cell antigen-1 response and granulocyte lineage expansion by alcohol during septicemia.

OBJECTIVE: Granulocytopenia frequently occurs in alcohol abusers with severe bacterial infection, which strongly correlates with poor clinical outcome. Knowledge of the molecular mechanisms underlying the granulopoietic response to bacterial infection remains limited. This study investigated the involvement of stem cell antigen-1 expression by granulocyte lineage-committed progenitors in the granulopoietic response to septicemia and how alcohol affected this response. DESIGN: : Laboratory investigation. SETTING: University laboratory. SUBJECTS: Male Balb/c mice. INTERVENTIONS: Thirty mins after intraperitoneal injection of alcohol (20% ethanol in saline at 5 g of ethanol/kg) or saline, mice received an intravenous Escherichia coli challenge. MEASUREMENTS AND MAIN RESULTS: E. coli septicemia activated stem cell antigen-1 expression by marrow immature granulocyte differentiation antigen-1 precursors which correlated with an increase in proliferation, granulocyte macrophage colony-forming unit production, and expansion of this granulopoietic precursor cell pool. Acute alcohol treatment suppressed stem cell antigen-1 activation and inhibited the infection-induced increases in proliferation, granulocyte macrophage colony-forming unit production, and expansion the of immature granulocyte differentiation antigen-1 precursor cell population. Consequently, recovery of the marrow mature granulocyte differentiation antigen-1 cell population after E. coli challenge was impaired. Stem cell antigen-1 was induced in sorted granulocyte differentiation antigen-1, stem cell antigen-1' cells by lipopolysaccharide-stimulated C-Jun kinase activation that was also inhibited by alcohol. Furthermore, stem cell antigen-1 knockout mice failed to expand the marrow immature granulocyte differentiation antigen-1 cell pool and demonstrated fewer newly produced granulocytes in the circulation after the E. coli challenge. CONCLUSIONS: Alcohol suppresses the stem cell antigen-1 response in granulocyte lineage-committed precursors and restricts granulocyte production during septicemia, which may serve as a novel mechanism underlying impaired host defense in alcohol abusers.

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.