Respiratory Health Associated With Systemic Metal Exposure in Post-9/11 Veterans in the Department of Veterans Affairs Toxic Embedded Fragment Registry.

OBJECTIVE: Adverse respiratory outcomes in post-9/11 veterans with elevated urinary metal measures and enrolled in the VA's Toxic Embedded Fragment registry were compared to those without elevated urinary metals. METHODS: Veterans completed questionnaires, underwent pulmonary physiology tests (pulmonary function and oscillometry), and provided urine samples for analysis of 13 metals. Respiratory symptoms, diagnoses, and physiology measures were compared in veterans with ≥1 urine metal elevation to those without metal elevations, adjusted for covariates, including smoking. RESULTS: Among 402 study participants, 24% had elevated urine metals, often just exceeding upper limits of reference values. Compared to veterans without elevated metals, those with elevated metals had had higher FEV 1 values but similar frequencies of respiratory symptoms and diagnoses and abnormalities on pulmonary physiology tests. CONCLUSIONS: Mild systemic metal elevations in post-9/11 veterans are not associated with adverse respiratory health outcomes.

Association of antiplatelet therapy with clinical outcomes in patients with peripheral artery disease.

BACKGROUND: The beneficial role of dual anti-platelet therapy (DAPT) in coronary artery disease is well established. However, there is limited data describing the effects of DAPT in patients with atherosclerotic peripheral artery disease (PAD). The aim of this meta-analysis is to compare clinical outcomes associated with DAPT versus single anti-platelet therapy (SAPT) in patients with symptomatic PAD. METHODS: We performed a literature search for studies assessing the risk of adverse cardiovascular and limb events in cohorts receiving either DAPT or SAPT. The primary endpoint was all cause mortality. The secondary endpoints included graft failure, amputation, total bleeding, severe bleeding and fatal bleeding. The search included the following databases: Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar. The search was not restricted to time or publication status. RESULTS: A total of 11 studies with 54,331 participants (24,449 on SAPT and 29,882 on DAPT) were included. Patients with PAD treated with SAPT had higher all-cause mortality compared to patients treated with DAPT (OR 1.37, 95 % CI 1.09-1.74; p < 0.01). There was no difference in risk of graft failure or amputation between patients treated with SAPT or DAPT (OR 0.9, 95 % CI 0.77-1.06; p = 0.19; OR 1.11, 95 % CI 0.88-1.41; p = 0.37). Patients treated with SAPT had lower total bleeds compared to patients treated with DAPT (OR 0.53, 95 % CI 0.36-0.77; p < 0.01). However, For SAPT plus AC vs SAPT, a total of 8 studies with 17,100 participants (3447 with SAPT plus AC and 8619 with only SAPT) were included. Patients on SAPT plus AC did not have a statistically significant difference in risk for all-cause mortality, (OR 0.91, 95 % CI 0.67-1.24; p = 0.56). SAPT plus AC had significantly lower risk of MI (OR 0.82, 95 % CI 0.69-0.97; p = 0.02), amputation (OR 0.72, 95 % CI 0.53-0.97; p = 0.03), and graft failure (OR 0.66, 95 % CI 0.48-0.93; p = 0.02). There was no significant different in risk of fatal bleeding be-tween the two groups (OR 1.60, 95 % CI 0.76-3.35; p = 0.22). CONCLUSIONS: In patients with symptomatic PAD, a strategy of DAPT may confer a mortality benefit when compared to SAPT without significantly increasing the risk of serious bleeding events.

Localized hypoxia links ER stress to lung fibrosis through induction of C/EBP homologous protein.

ER stress in type II alveolar epithelial cells (AECs) is common in idiopathic pulmonary fibrosis (IPF), but the contribution of ER stress to lung fibrosis is poorly understood. We found that mice deficient in C/EBP homologous protein (CHOP), an ER stress-regulated transcription factor, were protected from lung fibrosis and AEC apoptosis in 3 separate models where substantial ER stress was identified. In mice treated with repetitive intratracheal bleomycin, we identified localized hypoxia in type II AECs as a potential mechanism explaining ER stress. To test the role of hypoxia in lung fibrosis, we treated mice with bleomycin, followed by exposure to 14% O2, which exacerbated ER stress and lung fibrosis. Under these experimental conditions, CHOP-/- mice, but not mice with epithelial HIF (HIF1/HIF2) deletion, were protected from AEC apoptosis and fibrosis. In vitro studies revealed that CHOP regulates hypoxia-induced apoptosis in AECs via the inositol-requiring enzyme 1α (IRE1α) and the PKR-like ER kinase (PERK) pathways. In human IPF lungs, CHOP and hypoxia markers were both upregulated in type II AECs, supporting a conclusion that localized hypoxia results in ER stress-induced CHOP expression, thereby augmenting type II AEC apoptosis and potentiating lung fibrosis.

Endogenous PGI2 signaling through IP inhibits neutrophilic lung inflammation in LPS-induced acute lung injury mice model.

Endogenous prostaglandin I2 (PGI2) has inhibitory effects on immune responses against pathogens or allergens; however, the immunomodulatory activity of endogenous PGI2 signaling in endotoxin-induced inflammation is unknown. To test the hypothesis that endogenous PGI2 down-regulates endotoxin-induced lung inflammation, C57BL/6 wild type (WT) and PGI2 receptor (IP) KO mice were challenged intranasally with LPS. Urine 6-keto-PGF1α, a stable metabolite of PGI2, was significantly increased following the LPS-challenge, suggesting that endogenous PGI2 signaling modulates the host response to LPS-challenge. IPKO mice had a significant increase in neutrophils in the BAL fluid as well as increased proteins of KC, LIX, and TNF-α in lung homogenates compared with WT mice. In contrast, IL-10 was decreased in LPS-challenged IPKO mice compared with WT mice. The PGI2 analog cicaprost significantly decreased LPS-induced KC, and TNF-α, but increased IL-10 and AREG in bone marrow-derived dendritic cells (BMDCs) and bone marrow-derived macrophages (BMMs) compared with vehicle-treatment. These results indicated that endogenous PGI2 signaling attenuated neutrophilic lung inflammation through the reduced inflammatory cytokine and chemokine and enhanced IL-10.

Loss of Nrf2 promotes alveolar type 2 cell loss in irradiated, fibrotic lung.

The development of radiation-induced pulmonary fibrosis represents a critical clinical issue limiting delivery of therapeutic doses of radiation to non-small cell lung cancer. Identification of the cell types whose injury initiates a fibrotic response and the underlying biological factors that govern that response are needed for developing strategies that prevent or mitigate fibrosis. C57BL/6 mice (wild type, Nrf2 null, Nrf2flox/flox, and Nrf2Δ/Δ; SPC-Cre) were administered a thoracic dose of 12Gy and allowed to recover for 250 days. Whole slide digital and confocal microscopy imaging of H&E, Masson's trichrome and immunostaining were used to assess tissue remodeling, collagen deposition and cell renewal/mobilization during the regenerative process. Histological assessment of irradiated, fibrotic wild type lung revealed significant loss of alveolar type 2 cells 250 days after irradiation. Type 2 cell loss and the corresponding development of fibrosis were enhanced in the Nrf2 null mouse. Yet, conditional deletion of Nrf2 in alveolar type 2 cells in irradiated lung did not impair type 2 cell survival nor yield an increased fibrotic phenotype. Instead, radiation-induced ΔNp63 stem/progenitor cell mobilization was inhibited in the Nrf2 null mouse while the propensity for radiation-induced myofibroblasts derived from alveolar type 2 cells was magnified. In summary, these results indicate that Nrf2 is an important regulator of irradiated lung's capacity to maintain alveolar type 2 cells, whose injury can initiate a fibrotic phenotype. Loss of Nrf2 inhibits ΔNp63 stem/progenitor mobilization, a key event for reconstitution of injured lung, while promoting a myofibroblast phenotype that is central for fibrosis.

Secretory IgA Deficiency in Individual Small Airways Is Associated with Persistent Inflammation and Remodeling.

RATIONALE: Maintenance of a surface immune barrier is important for homeostasis in organs with mucosal surfaces that interface with the external environment; however, the role of the mucosal immune system in chronic lung diseases is incompletely understood. OBJECTIVES: We examined the relationship between secretory IgA (SIgA) on the mucosal surface of small airways and parameters of inflammation and airway wall remodeling in chronic obstructive pulmonary disease (COPD). METHODS: We studied 1,104 small airways (<2 mm in diameter) from 50 former smokers with COPD and 39 control subjects. Small airways were identified on serial tissue sections and examined for epithelial morphology, SIgA, bacterial DNA, nuclear factor-κB activation, neutrophil and macrophage infiltration, and airway wall thickness. MEASUREMENTS AND MAIN RESULTS: Morphometric evaluation of small airways revealed increased mean airway wall thickness and inflammatory cell counts in lungs from patients with COPD compared with control subjects, whereas SIgA level on the mucosal surface was decreased. However, when small airways were classified as SIgA intact or SIgA deficient, we found that pathologic changes were localized almost exclusively to SIgA-deficient airways, regardless of study group. SIgA-deficient airways were characterized by (1) abnormal epithelial morphology, (2) invasion of bacteria across the apical epithelial barrier, (3) nuclear factor-κB activation, (4) accumulation of macrophages and neutrophils, and (5) fibrotic remodeling of the airway wall. CONCLUSIONS: Our findings support the concept that localized, acquired SIgA deficiency in individual small airways of patients with COPD allows colonizing bacteria to cross the epithelial barrier and drive persistent inflammation and airway wall remodeling, even after smoking cessation.

Clinical Characteristics and Angiographic Findings of Acute Myocardial Infarction Associated With Marijuana Use: Consecutive Case Series.

BACKGROUND: Marijuana use has been increasingly legalized in the United States resulting in substantial rise in the number of users especially in the younger populations. While our group and others had described various metabolic effects of this drug, little is known about its association with acute myocardial infarction. OBJECTIVE: To present a series of 8 patients with 10 events of ST-elevation MI (STEMI) associated with marijuana use; highlighting their demographic, clinical presentation, laboratory results and angiographic characteristics. METHODS: Retrospective chart review of patients with STEMI presenting to our inner city hospital Coronary Care Unit over a period of 4 years (December 2013-April 2017). RESULTS: Of the 10 case subjects studied who presented with chest pain, EKG evidence of STEMI with cannabis use, mean age at presentation was 40.1 ± 9.7 (years) SD, ranging from 26 to 59 years old. There were 9 males and one female, of them, 8 were Black, 2 Hispanic and 1 White. Of the 10 cases, 3 (30%) had no known cardiovascular disease (CVD) risk factors (RF) on admission, 1 patient had 3 RF, 4 patients had 2 RF and 2 had 1 CVD RF, which included age, diabetes mellitus type 2 (DM2), hypertension, dyslipidemia, smoking, and family history of premature coronary heart disease. Troponin I (cTnI) peak mean level was 93.5 ± 34.35 ng/ml, range 7.86 - 358.0 ng/ml. All patients had angiographic evidence of obstructive coronary angiography. CONCLUSION: In our study, marijuana use is associated with ST-elevation MI in largely minority population, occurring at a relatively younger age with half of the cases either low risk or CVD risk free. Additional studies are needed to further characterize this population given the increase in marijuana use.

Clinical Characteristics and Angiographic Findings of Myocardial Infarction among Marijuana Users and Non-Users.

BACKGROUND: Marijuana use has been increasingly legalized in the United States resulting in substantial rise in the number of users especially in the younger populations. While our group and others had described various metabolic effects of this drug, little is known about its association with acute myocardial infarction (AMI). OBJECTIVE: This follow up study presents contemporaneous cohort of non-THC user patients at a single, urban center hospital diagnosed with ST-elevation AMI; highlighting and comparing demographic, clinical, laboratory and angiographic characteristics based on exposure to THC at time of presentation. METHODS: Retrospective chart review of patients with ST-elevation AMI presenting to our inner city hospital Coronary Care Unit over a period of 4 years (December 2013-April 2017). RESULTS: Of the 10 case subjects studied whom presented with chest pain, EKG evidence of ST-elevation MI (STEMI) with cannabis use, mean age at presentation was 40 years old, which was 10 years younger than our control group with no marijuana use (n = 11, p = 0.107). Of the patients who had marijuana exposure upon admission, 3 (30%) had no known cardiovascular disease (CVD) risk factors (RF) on admission, 1 patient had 3 RF, 4 patients had 2 RF and 2 had 1 CVD risk factor, which included age, diabetes mellitus type 2 (DM2), hypertension, dyslipidemia, smoking status, and family history at time of triage. Patients who were negative for marijuana use had higher number of CVD risk factors present upon admission. ASCVD risk scores were 10% vs. 16% (p = 0.312). In angiographic findings, 100% of the marijuana users had 1 vessel disease compared with 55% in the non-users (p = 0.0351). Severity of stenosis for both groups was averaged at 93% for non-users vs 95% in THC users (p = 0.62414). Collateral vessels were visible during coronary arteriogram in 91% of non-THC users and in only 20% of THC users (p = 0.0019). Furthermore, non-users had 35% higher rate of Rentrop grade 1 collaterals (55% vs. 20%, p = 0.4872). Similar difference was shown in grade 2 collaterals between the two groups with non-users having 36% higher rate (36% vs. 0%, p = 0.0902). Amongst the patients who had collateral circulation present at the time of angiography (Rentrop grade >0), good collaterals (Rentrop grade 2 or 3) were present in 40% of non-THC users, while there was 0% presence of grade 2+ collaterals in THC users (p = 0.5152). CONCLUSION: In our study, marijuana use is associated with ST-elevation MI in largely minority population, occurring at a relatively younger age with half of the cases CVD risk free. Additional studies are needed to further characterize this population given the increase in marijuana use.

Epithelial-macrophage interactions determine pulmonary fibrosis susceptibility in Hermansky-Pudlak syndrome.

Alveolar epithelial cell (AEC) dysfunction underlies the pathogenesis of pulmonary fibrosis in Hermansky-Pudlak syndrome (HPS) and other genetic syndromes associated with interstitial lung disease; however, mechanisms linking AEC dysfunction and fibrotic remodeling are incompletely understood. Since increased macrophage recruitment precedes pulmonary fibrosis in HPS, we investigated whether crosstalk between AECs and macrophages determines fibrotic susceptibility. We found that AECs from HPS mice produce excessive MCP-1, which was associated with increased macrophages in the lungs of unchallenged HPS mice. Blocking MCP-1/CCR2 signaling in HPS mice with genetic deficiency of CCR2 or targeted deletion of MCP-1 in AECs normalized macrophage recruitment, decreased AEC apoptosis, and reduced lung fibrosis in these mice following treatment with low-dose bleomycin. We observed increased TGF-ß production by HPS macrophages, which was eliminated by CCR2 deletion. Selective deletion of TGF-ß in myeloid cells or of TGF-ß signaling in AECs through deletion of TGFBR2 protected HPS mice from AEC apoptosis and bleomycin-induced fibrosis. Together, these data reveal a feedback loop in which increased MCP-1 production by dysfunctional AECs results in recruitment and activation of lung macrophages that produce TGF-ß, thus amplifying the fibrotic cascade through AEC apoptosis and stimulation of fibrotic remodeling.

Endothelial HIF signaling regulates pulmonary fibrosis-associated pulmonary hypertension.

Pulmonary hypertension (PH) complicating chronic parenchymal lung disease, such as idiopathic pulmonary fibrosis, results in significant morbidity and mortality. Since the hypoxia-inducible factor (HIF) signaling pathway is important for development of pulmonary hypertension in chronic hypoxia, we investigated whether HIF signaling in vascular endothelium regulates development of PH related to pulmonary fibrosis. We generated a transgenic model in which HIF is deleted within vascular endothelial cells and then exposed these mice to chronic intraperitoneal bleomycin to induce PH associated with lung fibrosis. Although no differences in the degree of fibrotic remodeling were observed, we found that endothelial HIF-deficient mice were protected against development of PH, including right ventricle and pulmonary vessel remodeling. Similarly, endothelial HIF-deficient mice were protected from PH after a 4-wk exposure to normobaric hypoxia. In vitro studies of pulmonary vascular endothelial cells isolated from the HIF-targeted mice and controls revealed that endothelial HIF signaling increases endothelial cell expression of connective tissue growth factor, enhances vascular permeability, and promotes pulmonary artery smooth muscle cell proliferation and wound healing ability, all of which have the potential to impact the development of PH in vivo. Taken together, these studies demonstrate that vascular endothelial cell HIF signaling is necessary for development of hypoxia and pulmonary fibrosis associated PH. As such, HIF and HIF-regulated targets represent a therapeutic target in these conditions.

Expression of mutant bone morphogenetic protein receptor II worsens pulmonary hypertension secondary to pulmonary fibrosis.

Pulmonary fibrosis is often complicated by pulmonary hypertension (PH), and previous studies have shown a potential link between bone morphogenetic protein receptor II (BMPR2) and PH secondary to pulmonary fibrosis. We exposed transgenic mice expressing mutant BMPR2 and control mice to repetitive intraperitoneal injections of bleomycin for 4 weeks. The duration of transgene activation was too short for mutant BMPR2 mice to develop spontaneous PH. Mutant BMPR2 mice had increased right ventricular systolic pressure compared to control mice, without differences in pulmonary fibrosis. We found increased hypoxia-inducible factor (HIF)1-α stabilization in lungs of mutant-BMPR2-expressing mice compared to controls following bleomycin treatment. In addition, expression of the hypoxia response element protein connective tissue growth factor was increased in transgenic mice as well as in a human pulmonary microvascular endothelial cell line expressing mutant BMPR2. In mouse pulmonary vascular endothelial cells, mutant BMPR2 expression resulted in increased HIF1-α and reactive oxygen species production following exposure to hypoxia, both of which were attenuated with the antioxidant TEMPOL. These data suggest that expression of mutant BMPR2 worsens secondary PH through increased HIF activity in vascular endothelium. This pathway could be therapeutically targeted in patients with PH secondary to pulmonary fibrosis.

Secretory IgA from submucosal glands does not compensate for its airway surface deficiency in chronic obstructive pulmonary disease.

Secretory immunoglobulin A (SIgA) reaches the airway lumen by local transcytosis across airway epithelial cells or with tracheobronchial submucosal gland secretions. In chronic obstructive pulmonary disease (COPD), deficiency of SIgA on the airway surface has been reported. However, reduction of SIgA levels in sputum and bronchoalveolar lavage (BAL) fluid has not been consistently observed. To explain this discrepancy, we analyzed BAL fluid and lung tissue from patients with COPD and control subjects. Immunohistochemical analysis of large and small airways of COPD patients showed that MUC5AC is the predominant mucin expressed by airway epithelial cells, whereas MUC5B is expressed in submucosal glands of large airways. Dual immunostaining with anti-IgA and anti-MUC5B antibodies showed reduction of IgA on the airway surface as well as accumulation of IgA within MUC5B-positive luminal mucus plugs, suggesting that luminal SIgA originates from submucosal glands in COPD patients. We found that the concentration of SIgA in BAL is inversely correlated with forced expiratory volume in 1 s (FEV1) in COPD, but that the ratio of SIgA/MUC5B is a better predictor of FEV1, particularly in patients with moderate COPD. Together, these findings suggest that SIgA production by submucosal glands, which are expanded in COPD, is insufficient to compensate for reduced SIgA transcytosis by airway epithelial cells. Localized SIgA deficiency on the surface of small airways is associated with COPD progression and represents a potential new therapeutic target in COPD.

Enhanced External Counterpulsation Is Cost-Effective in Reducing Hospital Costs in Refractory Angina Patients.

BACKGROUND: Enhanced external counterpulsation (EECP) is effective in the treatment of refractory angina, a condition suffered by 1.7 million Americans. Declining cardiovascular mortality and appropriate use criteria may further increase this number. HYPOTHESIS: EECP is hypothesized to be cost-effective in reducing hospitalizations in refractory angina patients. METHODS: The data used in this analysis were collected in phase II of the International EECP Patient Registry (IEPR-II). Data were collected on changes in Canadian Cardiovascular Society functional class, Duke Activity Status Index, and number of hospitalizations in the 6 months prior to EECP and in the 6- and 12-month intervals following EECP. Estimates of the changes in annual cost of all-cause hospitalization before and after EECP therapy were calculated by the product of the differences in hospitalization rates in the 6-month interval before and after EECP treatment and estimated hospitalization and physician charges after subtracting the average cost of EECP. RESULTS: Data for 1015 patients were analyzed. Hospitalization occurred in 55.2% of patients, an average of 1.7 ± 1.4 hospitalizations/patient, in the 6-month period before 35 hours of EECP; and in 24.4%, an average of 1.4 ± 1.0 hospitalizations/patient, during the 6- to 12-month period after EECP. The average hospitalization and physician charge in the US was $17,995, and the average EECP cost was $4880, yielding an annual cost savings/patient of $17,074. CONCLUSIONS: Treatment of refractory angina patients with EECP resulted in improvement in angina and functional class accompanied by a sustained reduction in health care costs over 1 year of follow-up.

Percutaneous Ventricular Assist Devices and ECMO in the Management of Acute Decompensated Heart Failure.

The successful treatment of acute decompensated heart failure continues to evolve with an increasing utilization of nondurable mechanical support devices. Indications for acute support have broadened to include their use as a bridge to recovery or decision (for durable ventricular assist devices [VADs] or heart transplant). Available devices have improved in terms of effectiveness, ease of insertion, and reduction in complications. The commonly used devices (intra-aortic balloon pump, TandemHeart, Impella, and extracorporeal membrane oxygenation circuit), together with their mechanisms of action, are reviewed. Current considerations for support, specific to each device, are examined and future directions and indications for percutaneous VADs are explored.

Regulation of alveolar procoagulant activity and permeability in direct acute lung injury by lung epithelial tissue factor.

Tissue factor (TF) initiates the extrinsic coagulation cascade in response to tissue injury, leading to local fibrin deposition. Low levels of TF in mice are associated with increased severity of acute lung injury (ALI) after intratracheal LPS administration. However, the cellular sources of the TF required for protection from LPS-induced ALI remain unknown. In the current study, transgenic mice with cell-specific deletions of TF in the lung epithelium or myeloid cells were treated with intratracheal LPS to determine the cellular sources of TF important in direct ALI. Cell-specific deletion of TF in the lung epithelium reduced total lung TF expression to 39% of wild-type (WT) levels at baseline and to 29% of WT levels after intratracheal LPS. In contrast, there was no reduction of TF with myeloid cell TF deletion. Mice lacking myeloid cell TF did not differ from WT mice in coagulation, inflammation, permeability, or hemorrhage. However, mice lacking lung epithelial TF had increased tissue injury, impaired activation of coagulation in the airspace, disrupted alveolar permeability, and increased alveolar hemorrhage after intratracheal LPS. Deletion of epithelial TF did not affect alveolar permeability in an indirect model of ALI caused by systemic LPS infusion. These studies demonstrate that the lung epithelium is the primary source of TF in the lung, contributing 60-70% of total lung TF, and that lung epithelial, but not myeloid, TF may be protective in direct ALI.

Telomerase deficiency delays renal recovery in mice after ischemia-reperfusion injury by impairing autophagy.

The aged population suffers increased morbidity and higher mortality in response to episodes of acute kidney injury (AKI). Aging is associated with telomere shortening, and both telomerase reverse transcriptase (TerT) and RNA (TerC) are essential to maintain telomere length. To define a role of telomerase deficiency in susceptibility to AKI, we used ischemia/reperfusion injury in wild-type mice or mice with either TerC or TerT deletion. Injury induced similar renal impairment at day 1 in each genotype, as assessed by azotemia, proteinuria, acute tubular injury score, and apoptotic tubular epithelial cell index. However, either TerC or TerT knockout significantly delayed recovery compared with wild-type mice. Electron microscopy showed increased autophagosome formation in renal tubular epithelial cells in wild-type mice but a significant delay of their development in TerC and TerT knockout mice. There were also impeded increases in the expression of the autophagosome marker LC3 II, prolonged accumulation of the autophagosome protein P62, an increase of the cell cycle regulator p16, and greater activation of the mammalian target of rapamycin (mTOR) pathway. The mTORC1 inhibitor, rapamycin, partially restored the ischemia/reperfusion-induced autophagy response, without a significant effect on either p16 induction or tubule epithelial cell proliferation. Thus, muting the maintenance of normal telomere length in mice impaired recovery from AKI, owing to an increase in tubule cell senescence and impairment of mTOR-mediated autophagy.