Xanthine oxidoreductase gene polymorphisms are associated with high risk of sepsis and organ failure.

BACKGROUND: Sepsis and associated organ failures confer substantial morbidity and mortality. Xanthine oxidoreductase (XOR) is implicated in the development of tissue oxidative damage in a wide variety of respiratory and cardiovascular disorders including sepsis and sepsis-associated acute respiratory distress syndrome (ARDS). We examined whether single nucleotide polymorphisms (SNPs) in the XDH gene (encoding XOR) might influence susceptibility to and outcome in patients with sepsis. METHODS: We genotyped 28 tag SNPs in XDH gene in the CELEG cohort, including 621 European American (EA) and 353 African American (AA) sepsis patients. Serum XOR activity was measured in a subset of CELEG subjects. Additionally, we assessed the functional effects of XDH variants utilizing empirical data from different integrated software tools and datasets. RESULTS: Among AA patients, six intronic variants (rs206805, rs513311, rs185925, rs561525, rs2163059, rs13387204), in a region enriched with regulatory elements, were associated with risk of sepsis (P < 0.008-0.049). Two out of six SNPs (rs561525 and rs2163059) were associated with risk of sepsis-associated ARDS in an independent validation cohort (GEN-SEP) of 590 sepsis patients of European descent. Two common SNPs (rs1884725 and rs4952085) in tight linkage disequilibrium (LD) provided strong evidence for association with increased levels of serum creatinine (Padjusted<0.0005 and 0.0006, respectively), suggesting a role in increased risk of renal dysfunction. In contrast, among EA ARDS patients, the missense variant rs17011368 (I703V) was associated with enhanced mortality at 60-days (P < 0.038). We found higher serum XOR activity in 143 sepsis patients (54.5 ± 57.1 mU/mL) compared to 31 controls (20.9 ± 12.4 mU/mL, P = 1.96 × 10- 13). XOR activity was associated with the lead variant rs185925 among AA sepsis patients with ARDS (P < 0.005 and Padjusted<0.01). Multifaceted functions of prioritized XDH variants, as suggested by various functional annotation tools, support their potential causality in sepsis. CONCLUSIONS: Our findings suggest that XOR is a novel combined genetic and biochemical marker for risk and outcome in patients with sepsis and ARDS.

The ENTPD1 promoter polymorphism -860 A > G (rs3814159) is associated with increased gene transcription, protein expression, CD39/NTPDase1 enzymatic activity, and thromboembolism risk.

Ectonucleoside triphosphate diphosphohydrolase 1 (NTPDase1) degrades the purines ATP and ADP that are key regulators of inflammation and clotting. We hypothesized that NTPDase1 polymorphisms exist and that they regulate this pathway. We sequenced the ENTPD1 gene (encoding NTPDase1) in 216 subjects then assessed genotypes in 2 cohorts comprising 2213 humans to identify ENTPD1 polymorphisms associated with venous thromboembolism (VTE). The G allele of the intron 1 polymorphism rs3176891 was more common in VTE vs. controls (odds ratio 1.26-1.9); it did not affect RNA splicing, but it was in strong linkage disequilibrium with the G allele of the promoter polymorphism rs3814159, which increased transcriptional activity by 8-fold. Oligonucleotides containing the G allele of this promoter region bound nuclear extracts more avidly. Carriers of rs3176891 G had endothelial cells with increased NTPDase1 activity and protein expression, and had platelets with enhanced aggregation. Thus, the G allele of rs3176891 marks a haplotype associated with increased clotting and platelet aggregation attributable to a promoter variant associated with increased transcription, expression, and activity of NTPDase1. We term this gain-of-function phenotype observed with rs3814159 G "CD39 Denver."-Maloney, J. P., Branchford, B. R., Brodsky, G. L., Cosmic, M. S., Calabrese, D. W., Aquilante, C. L., Maloney, K. W., Gonzalez, J. R., Zhang, W., Moreau, K. L., Wiggins, K. L., Smith, N. L., Broeckel, U., Di Paola, J. The ENTPD1 promoter polymorphism -860 A > G (rs3814159) is associated with increased gene transcription, protein expression, CD39/NTPDase1 enzymatic activity, and thromboembolism risk.

Decreased TGF-ß1 and VEGF Release in Cystic Fibrosis Platelets: Further Evidence for Platelet Defects in Cystic Fibrosis.

PURPOSE: Cystic fibrosis (CF) patients suffer from chronic lung inflammation. This inflammation may activate platelets. There are limited data on the role of platelet-secreted cytokines in CF. Platelet cytokines with inflammatory effects include vascular endothelial growth factor (VEGF) and transforming growth factor-ß1 (TGF-ß1). As levels of these cytokines are tenfold greater in serum than plasma due to platelet release, serum levels may be one index of platelet content, but a more specific index is release during the aggregation of isolated platelets. We postulated that altered release of these platelet cytokines occurs in CF. METHODS: We obtained sera and plasma from CF outpatients (n = 21) and from healthy controls (n = 20), measured VEGF and TGF-ß1, assessed for correlations with platelet number, analyzed cytokine release during platelet aggregation to collagen, and analyzed differences in maximal platelet aggregation. RESULTS: Platelet number and maximal aggregation levels were higher in CF. Plasma and serum levels of TGF-ß1 and VEGF were higher in CF, but these levels were similar after adjusting for platelet number (serum cytokines correlated with platelet count). The release of VEGF and TGF-ß1 during aggregation was decreased in CF platelets (by 52 and 29 %, respectively). CONCLUSION: Platelet release is not a source of the elevated blood proinflammatory cytokines TGF-ß1 and VEGF in CF, as platelets from CF patients actually release less of these cytokines. These data provide further evidence for platelet defects in CF.

Proinflammatory Cytokines Increase Vascular Endothelial Growth Factor Expression in Alveolar Epithelial Cells.

Vascular endothelial growth factor (VEGF) is an endothelial permeability mediator that is highly expressed in lung epithelium. In nonlung cells proinflammatory cytokines have been shown to increase VEGF expression, but their effects on lung epithelium remain unclear. We hypothesized that increases in alveolar epithelial cell VEGF RNA and protein expression occur after exposure to proinflammatory cytokines. We tested this using human alveolar epithelial cells (A549) stimulated with 5 proinflammatory cytokines. VEGF RNA expression was increased 1.4-2.7-fold in response to IL-1, IL-6, IL-8, TNF-α, or TGF-ß over 6 hours, with TGF-ß having the largest response. TNF-α increased VEGF RNA as early as 1 hour. A mix of IL-1, IL-6, and IL-8 had effects similar to IL-1. TNF-α increased protein expression as early as 4 hours and had a sustained effect at 16 hours, whereas IL-1 did not increase protein expression. Only VEGF165 was present in cultured A549 cells, yet other isoforms were seen in human lung tissue. Increased expression of VEGF in alveolar epithelial cells occurs in response to proinflammatory cytokines. Increased VEGF expression likely contributes to the pathogenesis of inflammatory lung diseases and to the angiogenic phenotype of lung cancer, a disease typically preceded by chronic inflammation.

Cadaveric emergency cricothyrotomy training for non-surgeons using a bronchoscopy-enhanced curriculum.

BACKGROUND: Emergency cricothyrotomy training for non-surgeons is important as rare "cannot intubate or oxygenate events" may occur multiple times in a provider's career when surgical expertise is not immediately available. However, such training is highly variable and often infrequent, therefore, enhancing these experiences is important. RESEARCH QUESTION: Is bronchoscopy-enhanced cricothyrotomy training in cadavers feasible, and what are the potential benefits provided by this innovation for trainees? METHODS: This study was performed during implementation of a new program to train non-surgeon providers on cadaveric donors on our campus. Standard training with an instructional video and live coaching was enhanced by bronchoscopic visualization of the trachea allowing participants to review their technique after performing scalpel and Seldinger-technique procedures, and to review their colleagues' technique on live video. Feasibility was measured through assessing helpfulness for trainees, cost, setup time, quality of images, and operator needs. Footage from the bronchoscopy recordings was analyzed to assess puncture-to-tube time, safety errors, and evidence for a training effect within groups. Participants submitted pre- and post-session surveys assessing their levels of experience and gauging their confidence and anxiety with cricothyrotomies. RESULTS: The training program met feasibility criteria for low costs (<200 USD/donor), setup time (<30 minutes/donor), and operator needs (1/donor). Furthermore, all participants rated the cadaveric session as helpful. Participants demonstrated efficient technique, with a median puncture-to-tube time of 48.5 seconds. Bronchoscopy recordings from 24 analyzed videos revealed eight instances of sharp instruments puncturing the posterior tracheal wall (33% rate), and two instances of improper tube placement (8% rate). Sharp instruments reached potentially dangerous insertion depths beyond the midpoint of the anterior-posterior diameter of the trachea in 58.3% of videos. Bronchoscopic enhancement was rated as quite or extremely helpful for visualizing the trachea (83.3%) and to assess depth of instrumentation (91.7%). There was a significant average increase in confidence (64.4%, P<0.001) and average decrease in performance anxiety (-11.6%, P = 0.0328) after the session. A training effect was seem wherein the last trainee in each group had no posterior tracheal wall injuries. INTERPRETATION: Supplementing cadaveric emergent cricothyrotomy training programs with tracheal bronchoscopy is feasible, helpful to trainees, and meets prior documented times for efficient technique. Furthermore, it was successful in detecting technical errors that would have been missed in a standard training program. Bronchoscopic enhancement is a valuable addition to cricothyrotomy cadaveric training programs and may help avoid real-life complications.

Activation and pro-inflammatory cytokine production by unswitched memory B cells during SARS-CoV-2 infection.

Memory B cells are comprised of unswitched (CD27+IgD+) and switched (CD27+IgD-) subsets. The origin and function of unswitched human memory B cells are debated in the literature, whereas switched memory B cells are primed to respond to recurrent infection. Unswitched memory B cells have been described to be reduced in frequency with severe SARS-CoV2 infection and here we characterize their activation status, BCR functionality, and contribution to virally-induced cytokine production. Analyses of whole blood from healthy individuals, people immunized against SARS-CoV2, and those who have had mild and severe SARS-CoV2 infection, confirm a reduction in the frequency of unswitched memory B cells during severe SARS-CoV2 infection and demonstrate this reduction is associated with increased levels of systemic TNFα. We further document how severe viral infection is associated with an increased frequency of 'IgD+' only memory B cells that correlate with increased IgG autoantibody levels. Unswitched and switched memory B cells from severe SARS-CoV2 infection displayed evidence of heightened activation with a concomitant reduction in the expression of the inhibitory receptor CD72. Functionally, both populations of memory B cells from severe SARS-COV2 infection harbored a signaling-competent BCR that displayed enhanced BCR signaling activity in the unswitched population. Finally, we demonstrate that B cells from mild SARS-CoV2 infection are poised to secrete pro-inflammatory cytokines IL-6 and TNFα. Importantly, unswitched memory B cells were a major producer of IL-6 and switched memory B cells were a major producer of TNFα in response to viral TLR ligands. Together these data indicate that B cells contribute to the inflammatory milieu during viral infection.

Previous corticosteroid exposure associates with an increased Pneumocystis jirovecii pneumonia mortality among HIV-negative patients: a global research network with a follow-up multicenter case-control study.

Background: HIV-negative patients have substantial mortality from Pneumocystis jirovecii pneumonia (PJP). We lack predictors of HIV-negative PJP-associated mortality. Objective: We aim to characterize the role of prior corticosteroid exposure in PJP-related mortality. Methods: We queried a global research network to identify adult HIV-negative patients with PJP with or without corticosteroid exposure in the preceding year before diagnosis (n = 8,021). We performed a propensity score-matched analysis to adjust baseline patient characteristics and analyzed outcomes. We follow-up the results with a multicenter ten years retrospective case-control cohort of HIV-negative patients tested for PJP by PCP Direct Fluorescent Antigen. We used a Cox proportional hazards model for survival analysis. Results: 1822 HIV-negative propensity-scored matched patients with prior corticosteroid exposure had significantly increased 10 weeks (16% versus 9%, p < 0.0001) and one-year mortality after PJP diagnosis (23% versus 14%, p < 0.0001). (1→3)-ß-D-glucan (197.6 ± 155.8 versus 63 ± 0 pg/ml, p = 0.014), ferritin levels (1227 ± 2486 versus 768 ± 1060 mcg/l, p = 0.047), lymphopenia (1.5 ± 1.5 versus 2.0 ± 1.6 103 cells/µl, p < 0.0001) and hypoxia (SatO2: 86.7% versus 91.6%, p < 0.0001) were higher or worse in those with prior steroid use. Patients who died were more likely to have previously received dexamethasone (35% versus 16%, p < 0.001) or prednisone (49% versus 29%, p < 0.001). Adjusted Cox proportional-hazard model validation showed an independently increased mortality at 10 weeks (HR: 3.7, CI: 1.5-9.2, p = 0.004) and 1 year (HR: 4.5, CI: 2.0-10.4, p < 0.0001) among HIV-negative patients with previous corticosteroid exposure. Conclusion: Preceding corticosteroids in HIV-negative patients with PJP are associated with higher mortality. A higher fungal burden may influence corticosteroid-mediated mortality. Assessment of PJP prophylaxis must become a standard clinical best practice when instituting corticosteroid therapy courses.

Loss-of-function thrombospondin-1 mutations in familial pulmonary hypertension.

Most patients with familial pulmonary arterial hypertension (FPAH) carry mutations in the bone morphogenic protein receptor 2 gene (BMPR2). Yet carriers have only a 20% risk of disease, suggesting that other factors influence penetrance. Thrombospondin-1 (TSP1) regulates activation of TGF-ß and inhibits endothelial and smooth muscle cell proliferation, pathways coincidentally altered in pulmonary arterial hypertension (PAH). To determine whether a subset of FPAH patients also have mutations in the TSP1 gene (THBS1) we resequenced the type I repeats of THBS1 encoding the TGF-ß regulation and cell growth inhibition domains in 60 FPAH probands, 70 nonfamilial PAH subjects, and in large control groups. We identified THBS1 mutations in three families: a novel missense mutation in two (Asp362Asn), and an intronic mutation in a third (IVS8+255 G/A). Neither mutation was detected in population controls. Mutant 362Asn TSP1 had less than half of the ability of wild-type TSP1 to activate TGF-ß. Mutant 362Asn TSP1 also lost the ability to inhibit growth of pulmonary arterial smooth muscle cells and was over threefold less effective at inhibiting endothelial cell growth. The IVS8+255 G/A mutation decreased and/or eliminated local binding of the transcription factors SP1 and MAZ but did not affect RNA splicing. These novel mutations implicate THBS1 as a modifier gene in FPAH. These THBS1 mutations have implications in the genetic evaluation of FPAH patients. However, since FPAH is rare, these data are most relevant as evidence for the importance of TSP1 in pulmonary vascular homeostasis. Further examination of THBS1 in the pathogenesis of PAH is warranted.

Microvascular significance of TGF-ß axis activation in COVID-19.

As 2023 approaches, the COVID-19 pandemic has killed millions. While vaccines have been a crucial intervention, only a few effective medications exist for prevention and treatment of COVID-19 in breakthrough cases or in unvaccinated or immunocompromised patients. SARS-CoV-2 displays early and unusual features of micro-thrombosis and immune dysregulation that target endothelial beds of the lungs, skin, and other organs. Notably, anticoagulation improves outcomes in some COVID-19 patients. The protein transforming growth factor-beta (TGF-ß1) has constitutive roles in maintaining a healthy microvasculature through its roles in regulating inflammation, clotting, and wound healing. However, after infection (including viral infection) TGF-ß1 activation may augment coagulation, cause immune dysregulation, and direct a path toward tissue fibrosis. Dysregulation of TGF-ß signaling in immune cells and its localization in areas of microvascular injury are now well-described in COVID-19, and such events may contribute to the acute respiratory distress syndrome and skin micro-thrombosis outcomes frequently seen in severe COVID-19. The high concentration of TGF-ß in platelets and in other cells within microvascular thrombi, its ability to activate the clotting cascade and dysregulate immune pathways, and its pro-fibrotic properties all contribute to a unique milieu in the COVID-19 microvasculature. This unique environment allows for propagation of microvascular clotting and immune dysregulation. In this review we summarize the physiological functions of TGF-ß and detail the evidence for its effects on the microvasculature in COVID-19. In addition, we explore the potential role of existing TGF-ß inhibitors for the prevention and treatment of COVID-19 associated microvascular thrombosis and immune dysregulation.

SARS-CoV-2 infection relaxes peripheral B cell tolerance.

Severe SARS-CoV-2 infection is associated with strong inflammation and autoantibody production against diverse self-antigens, suggesting a system-wide defect in B cell tolerance. BND cells are a B cell subset in healthy individuals harboring autoreactive but anergic B lymphocytes. In vitro evidence suggests inflammatory stimuli can breach peripheral B cell tolerance in this subset. We asked whether SARS-CoV-2-associated inflammation impairs BND cell peripheral tolerance. To address this, PBMCs and plasma were collected from healthy controls, individuals immunized against SARS-CoV-2, or subjects with convalescent or severe SARS-CoV-2 infection. We demonstrate that BND cells from severely infected individuals are significantly activated, display reduced inhibitory receptor expression, and restored BCR signaling, indicative of a breach in anergy during viral infection, supported by increased levels of autoreactive antibodies. The phenotypic and functional BND cell alterations significantly correlate with increased inflammation in severe SARS-CoV-2 infection. Thus, autoreactive BND cells are released from peripheral tolerance with SARS-CoV-2 infection, likely as a consequence of robust systemic inflammation.

Autoantibodies elicited with SARS-CoV-2 infection are linked to alterations in double negative B cells.

Double negative (DN) B cells (CD27-IgD-) comprise a heterogenous population of DN1, DN2, and the recently described DN3 and DN4 subsets. In autoimmune disease, DN2 cells are reported to be precursors to autoreactive antibody secreting cells and expansion of DN2 cells is linked to elevated interferon levels. Severe SARS-CoV-2 infection is characterized by elevated systemic levels of pro-inflammatory cytokines and serum autoantibodies and expansion of the DN2 subset in severe SARS-CoV-2 infection has been reported. However, the activation status, functional capacity and contribution to virally-induced autoantibody production by DN subsets is not established. Here, we validate the finding that severe SARS-CoV-2 infection is associated with a reduction in the frequency of DN1 cells coinciding with an increase in the frequency of DN2 and DN3 cells. We further demonstrate that with severe viral infection DN subsets are at a heightened level of activation, display changes in immunoglobulin class isotype frequency and have functional BCR signaling. Increases in overall systemic inflammation (CRP), as well as specific pro-inflammatory cytokines (TNFα, IL-6, IFNγ, IL-1ß), significantly correlate with the skewing of DN1, DN2 and DN3 subsets during severe SARS-CoV-2 infection. Importantly, the reduction in DN1 cell frequency and expansion of the DN3 population during severe infection significantly correlates with increased levels of serum autoantibodies. Thus, systemic inflammation during SARS-CoV-2 infection drives changes in Double Negative subset frequency, likely impacting their contribution to generation of autoreactive antibodies.

Short women with severe sepsis-related acute lung injury receive lung protective ventilation less frequently: an observational cohort study.

INTRODUCTION: Lung protective ventilation (LPV) has been shown to improve survival and the duration of mechanical ventilation in acute lung injury (ALI) patients. Mortality of ALI may vary by gender, which could result from treatment variability. Whether gender is associated with the use of LPV is not known. METHODS: A total of 421 severe sepsis-related ALI subjects in the Consortium to Evaluate Lung Edema Genetics from seven teaching hospitals between 2002 and 2008 were included in our study. We evaluated patients' tidal volume, plateau pressure and arterial pH to determine whether patients received LPV during the first two days after developing ALI. The odds ratio of receiving LPV was estimated by a logistic regression model with robust and cluster options. RESULTS: Women had similar characteristics as men with the exception of lower height and higher illness severity, as measured by Acute Physiology and Chronic Health Evaluation (APACHE) II score. 225 (53%) of the subjects received LPV during the first two days after ALI onset; women received LPV less frequently than men (46% versus 59%, P < 0.001). However, after adjustment for height and severity of illness (APACHE II), there was no difference in exposure to LPV between men and women (P = 0.262). CONCLUSIONS: Short people are less likely to receive LPV, which seems to explain the tendency of clinicians to adhere to LPV less strictly in women. Strategies to standardize application of LPV, independent of differences in height and severity of illness, are necessary.

Histopathological Correlation of Acute on Chronic Eosinophilic Pneumonitis Caused by Vaporized Cannabis Oil Inhalation.

Whether eosinophilic pneumonitis represents a true manifestation of e-cigarette, or vaping, product use-associated lung injury remains uncertain, and this ambiguity stems from a lack of histopathological data. We present a previously healthy young woman whose asthma-like symptoms and histopathologic finding of eosinophilic pneumonitis were caused by inhalation of vaporized cannabis hash oil concentrates. This report provides compelling evidence that eosinophilic pneumonitis can result from cannabis hash oil inhalation.

Hypothesis: Alpha-1-antitrypsin is a promising treatment option for COVID-19.

No definitive treatment for COVID-19 exists although promising results have been reported with remdesivir and glucocorticoids. Short of a truly effective preventive or curative vaccine against SARS-CoV-2, it is becoming increasingly clear that multiple pathophysiologic processes seen with COVID-19 as well as SARS-CoV-2 itself should be targeted. Because alpha-1-antitrypsin (AAT) embraces a panoply of biologic activities that may antagonize several pathophysiologic mechanisms induced by SARS-CoV-2, we hypothesize that this naturally occurring molecule is a promising agent to ameliorate COVID-19. We posit at least seven different mechanisms by which AAT may alleviate COVID-19. First, AAT is a serine protease inhibitor (SERPIN) shown to inhibit TMPRSS-2, the host serine protease that cleaves the spike protein of SARS-CoV-2, a necessary preparatory step for the virus to bind its cell surface receptor ACE2 to gain intracellular entry. Second, AAT has anti-viral activity against other RNA viruses HIV and influenza as well as induces autophagy, a known host effector mechanism against MERS-CoV, a related coronavirus that causes the Middle East Respiratory Syndrome. Third, AAT has potent anti-inflammatory properties, in part through inhibiting both nuclear factor-kappa B (NFκB) activation and ADAM17 (also known as tumor necrosis factor-alpha converting enzyme), and thus may dampen the hyper-inflammatory response of COVID-19. Fourth, AAT inhibits neutrophil elastase, a serine protease that helps recruit potentially injurious neutrophils and implicated in acute lung injury. AAT inhibition of ADAM17 also prevents shedding of ACE2 and hence may preserve ACE2 inhibition of bradykinin, reducing the ability of bradykinin to cause a capillary leak in COVID-19. Fifth, AAT inhibits thrombin, and venous thromboembolism and in situ microthrombi and macrothrombi are increasingly implicated in COVID-19. Sixth, AAT inhibition of elastase can antagonize the formation of neutrophil extracellular traps (NETs), a complex extracellular structure comprised of neutrophil-derived DNA, histones, and proteases, and implicated in the immunothrombosis of COVID-19; indeed, AAT has been shown to change the shape and adherence of non-COVID-19-related NETs. Seventh, AAT inhibition of endothelial cell apoptosis may limit the endothelial injury linked to severe COVID-19-associated acute lung injury, multi-organ dysfunction, and pre-eclampsia-like syndrome seen in gravid women. Furthermore, because both NETs formation and the presence of anti-phospholipid antibodies are increased in both COVID-19 and non-COVID pre-eclampsia, it suggests a similar vascular pathogenesis in both disorders. As a final point, AAT has an excellent safety profile when administered to patients with AAT deficiency and is dosed intravenously once weekly but also comes in an inhaled preparation. Thus, AAT is an appealing drug candidate to treat COVID-19 and should be studied.

Interstitial macrophage-derived thrombospondin-1 contributes to hypoxia-induced pulmonary hypertension.

AIMS: Transforming growth factor-ß (TGF-ß) signalling is required for chronic hypoxia-induced pulmonary hypertension (PH). The activation of TGF-ß by thrombospondin-1 (TSP-1) contributes to the pathogenesis of hypoxia-induced PH. However, neither the cellular source of pathologic TSP-1 nor the downstream signalling pathway that link activated TGF-ß to PH have been determined. In this study, we hypothesized that circulating monocytes, which are recruited to become interstitial macrophages (IMs), are the major source of TSP-1 in hypoxia-exposed mice, and TSP-1 activates TGF-ß with increased Rho-kinase signalling, causing vasoconstriction. METHODS AND RESULTS: Flow cytometry revealed that a specific subset of IMs is the major source of pathologic TSP-1 in hypoxia. Intravenous depletion and parabiosis experiments demonstrated that these cells are circulating prior to recruitment into the interstitium. Rho-kinase-mediated vasoconstriction was a major downstream target of active TGF-ß. Thbs1 deficient bone marrow (BM) protected against hypoxic-PH by blocking TGF-ß activation and Rho-kinase-mediated vasoconstriction. CONCLUSION: In hypoxia-challenged mice, BM derived and circulating monocytes are recruited to become IMs which express TSP-1, resulting in TGF-ß activation and Rho-kinase-mediated vasoconstriction.

Toll-like receptor 1 polymorphisms affect innate immune responses and outcomes in sepsis.

RATIONALE: Polymorphisms affecting Toll-like receptor (TLR)-mediated responses could predispose to excessive inflammation during an infection and contribute to an increased risk for poor outcomes in patients with sepsis. OBJECTIVES: To identify hypermorphic polymorphisms causing elevated TLR-mediated innate immune cytokine and chemokine responses and to test whether these polymorphisms are associated with increased susceptibility to death, organ dysfunction, and infections in patients with sepsis. METHODS: We screened single-nucleotide polymorphisms (SNPs) in 43 TLR-related genes to identify variants affecting TLR-mediated inflammatory responses in blood from healthy volunteers ex vivo. The SNP associated most strongly with hypermorphic responses was tested for associations with death, organ dysfunction, and type of infection in two studies: a nested case-control study in a cohort of intensive care unit patients with sepsis, and a case-control study using patients with sepsis, patients with sepsis-related acute lung injury, and healthy control subjects. MEASUREMENTS AND MAIN RESULTS: The SNP demonstrating the most hypermorphic effect was the G allele of TLR1(-7202A/G) (rs5743551), which associated with elevated TLR1-mediated cytokine production (P < 2 x 10(-20)). TLR1(-7202G) marked a coding SNP that causes higher TLR1-induced NF-kappaB activation and higher cell surface TLR1 expression. In the cohort of patients with sepsis TLR1(-7202G) predicted worse organ dysfunction and death (odds ratio, 1.82; 95% confidence interval, 1.07-3.09). In the case-control study TLR1(-7202G) was associated with sepsis-related acute lung injury (odds ratio, 3.40; 95% confidence interval, 1.59-7.27). TLR1(-7202G) also associated with a higher prevalence of gram-positive cultures in both clinical studies. CONCLUSIONS: Hypermorphic genetic variation in TLR1 is associated with increased susceptibility to organ dysfunction, death, and gram-positive infection in sepsis.

TGF-ß activation by bone marrow-derived thrombospondin-1 causes Schistosoma- and hypoxia-induced pulmonary hypertension.

Pulmonary arterial hypertension (PAH) is an obstructive disease of the precapillary pulmonary arteries. Schistosomiasis-associated PAH shares altered vascular TGF-ß signalling with idiopathic, heritable and autoimmune-associated etiologies; moreover, TGF-ß blockade can prevent experimental pulmonary hypertension (PH) in pre-clinical models. TGF-ß is regulated at the level of activation, but how TGF-ß is activated in this disease is unknown. Here we show TGF-ß activation by thrombospondin-1 (TSP-1) is both required and sufficient for the development of PH in Schistosoma-exposed mice. Following Schistosoma exposure, TSP-1 levels in the lung increase, via recruitment of circulating monocytes, while TSP-1 inhibition or knockout bone marrow prevents TGF-ß activation and protects against PH development. TSP-1 blockade also prevents the PH in a second model, chronic hypoxia. Lastly, the plasma concentration of TSP-1 is significantly increased in subjects with scleroderma following PAH development. Targeting TSP-1-dependent activation of TGF-ß could thus be a therapeutic approach in TGF-ß-dependent vascular diseases.

Epidemiology, risk factors, and genetics of high-altitude-related pulmonary disease.

High-altitude-related pulmonary disease is a spectrum of acute and chronic illnesses with a well-described epidemiology. The risk for these illnesses is related to well-known environmental risk factors and lesser-known but important genetic factors. Prevention of acute high-altitude illness is possible in most visitors from lower elevations. Chronic high-altitude illnesses have an important worldwide impact.

Detection of aspiration in enterally fed patients: a requiem for bedside monitors of aspiration.

BACKGROUND: Pulmonary aspiration of gastric and oropharyngeal contents is common in enterally fed patients. Detection of early aspiration in these patients has relied on clinical impression, the coloring of enteral feedings with dyes, and less commonly the detection of elevated glucose in tracheal aspirates. The potential benefits, risks, and clinical use of bedside monitors of aspiration are under increasing scrutiny. METHODS: Literature review. Although this review reflects the opinions of the authors, recommendations of an expert consensus panel (North American Summit on Aspiration, which included one author, J. P. Maloney) were also used to guide recommendations. The specific recommendations of that panel are presented elsewhere. RESULTS: No large prospective clinical trials have been done to evaluate the use and safety of bedside monitors for aspiration. Clinical impression remains a poor "gold standard" of aspiration diagnosis in enterally fed patients. The coloring of enteral feedings with blue dyes (chiefly FD&C Blue No.1) is ubiquitous in hospitals despite evidence that it is not sensitive and potentially harmful. Cases of absorption of blue dye from enteral feedings in patients with critical illness have raised concern about the safety of the blue dye method, particularly in light of apparent toxic effects of these dyes on mitochondria. The glucose detection method has not been embraced; it too has little use and is labor intensive. CONCLUSIONS: Use of colored dyes in enteral feedings and glucose detection methods should be abandoned. Nonrecumbent positioning is an evidenced-based method for aspiration prevention that needs to be re-emphasized. Novel bedside methods of detecting early aspiration are needed to supplement preventative strategies.

North American Summit on Aspiration in the Critically Ill Patient: consensus statement.

Aspiration is the leading cause of pneumonia in the intensive care unit and the most serious complication of enteral tube feeding (ETF). Although aspiration is common, the clinical consequences are variable because of differences in nature of the aspirated material and individual host responses. A number of defense mechanisms normally present in the upper aerodigestive system that protect against aspiration become compromised by clinical events that occur frequently in the critical care setting, subjecting the patient to increased risk. The true incidence of aspiration has been difficult to determine in the past because of vague definitions, poor assessment monitors, and varying levels of clinical recognition. Standardization of terminology is an important step in helping to define the problem, design appropriate research studies, and develop strategies to reduce risk. Traditional clinical monitors of glucose oxidase strips and blue food coloring (BFC) should no longer be used. A modified approach to use of gastric residual volumes and identification of clinical factors that predispose to aspiration allow for risk stratification and an algorhythm approach to the management of the critically ill patient on ETF. Although the patient with confirmed aspiration should be monitored for clinical consequences and receive supportive pulmonary care, ETF may be continued when accompanied by appropriate steps to reduce risk of further aspiration. Management strategies for treating aspiration pneumonia are based on degree of diagnostic certainty, time of onset, and host factors.