Architecture of the outbred brown fat proteome defines regulators of metabolic physiology.

Brown adipose tissue (BAT) regulates metabolic physiology. However, nearly all mechanistic studies of BAT protein function occur in a single inbred mouse strain, which has limited the understanding of generalizable mechanisms of BAT regulation over physiology. Here, we perform deep quantitative proteomics of BAT across a cohort of 163 genetically defined diversity outbred mice, a model that parallels the genetic and phenotypic variation found in humans. We leverage this diversity to define the functional architecture of the outbred BAT proteome, comprising 10,479 proteins. We assign co-operative functions to 2,578 proteins, enabling systematic discovery of regulators of BAT. We also identify 638 proteins that correlate with protection from, or sensitivity to, at least one parameter of metabolic disease. We use these findings to uncover SFXN5, LETMD1, and ATP1A2 as modulators of BAT thermogenesis or adiposity, and provide OPABAT as a resource for understanding the conserved mechanisms of BAT regulation over metabolic physiology.

A Quantitative Tissue-Specific Landscape of Protein Redox Regulation during Aging.

Mammalian tissues engage in specialized physiology that is regulated through reversible modification of protein cysteine residues by reactive oxygen species (ROS). ROS regulate a myriad of biological processes, but the protein targets of ROS modification that drive tissue-specific physiology in vivo are largely unknown. Here, we develop Oximouse, a comprehensive and quantitative mapping of the mouse cysteine redox proteome in vivo. We use Oximouse to establish several paradigms of physiological redox signaling. We define and validate cysteine redox networks within each tissue that are tissue selective and underlie tissue-specific biology. We describe a common mechanism for encoding cysteine redox sensitivity by electrostatic gating. Moreover, we comprehensively identify redox-modified disease networks that remodel in aged mice, establishing a systemic molecular basis for the long-standing proposed links between redox dysregulation and tissue aging. We provide the Oximouse compendium as a framework for understanding mechanisms of redox regulation in physiology and aging.

pH-Gated Succinate Secretion Regulates Muscle Remodeling in Response to Exercise.

In response to skeletal muscle contraction during exercise, paracrine factors coordinate tissue remodeling, which underlies this healthy adaptation. Here we describe a pH-sensing metabolite signal that initiates muscle remodeling upon exercise. In mice and humans, exercising skeletal muscle releases the mitochondrial metabolite succinate into the local interstitium and circulation. Selective secretion of succinate is facilitated by its transient protonation, which occurs upon muscle cell acidification. In the protonated monocarboxylic form, succinate is rendered a transport substrate for monocarboxylate transporter 1, which facilitates pH-gated release. Upon secretion, succinate signals via its cognate receptor SUCNR1 in non-myofibrillar cells in muscle tissue to control muscle-remodeling transcriptional programs. This succinate-SUCNR1 signaling is required for paracrine regulation of muscle innervation, muscle matrix remodeling, and muscle strength in response to exercise training. In sum, we define a bioenergetic sensor in muscle that utilizes intracellular pH and succinate to coordinate tissue adaptation to exercise.

Lactate regulates cell cycle by remodelling the anaphase promoting complex.

Lactate is abundant in rapidly dividing cells owing to the requirement for elevated glucose catabolism to support proliferation1-6. However, it is not known whether accumulated lactate affects the proliferative state. Here we use a systematic approach to determine lactate-dependent regulation of proteins across the human proteome. From these data, we identify a mechanism of cell cycle regulation whereby accumulated lactate remodels the anaphase promoting complex (APC/C). Remodelling of APC/C in this way is caused by direct inhibition of the SUMO protease SENP1 by lactate. We find that accumulated lactate binds and inhibits SENP1 by forming a complex with zinc in the SENP1 active site. SENP1 inhibition by lactate stabilizes SUMOylation of two residues on APC4, which drives UBE2C binding to APC/C. This direct regulation of APC/C by lactate stimulates timed degradation of cell cycle proteins, and efficient mitotic exit in proliferative human cells. This mechanism is initiated upon mitotic entry when lactate abundance reaches its apex. In this way, accumulation of lactate communicates the consequences of a nutrient-replete growth phase to stimulate timed opening of APC/C, cell division and proliferation. Conversely, persistent accumulation of lactate drives aberrant APC/C remodelling and can overcome anti-mitotic pharmacology via mitotic slippage. In sum, we define a biochemical mechanism through which lactate directly regulates protein function to control the cell cycle and proliferation.

Association of Catecholamine Dose, Lactate, and Shock Duration at Vasopressin Initiation With Mortality in Patients With Septic Shock.

OBJECTIVES: To determine the association of catecholamine dose, lactate concentration, and timing from shock onset at vasopressin initiation with in-hospital mortality. DESIGN: Retrospective, observational study using segmented and multivariable logistic regression to evaluate the associations of catecholamine dose, lactate concentration, and timing from shock onset at vasopressin initiation with in-hospital mortality. SETTING: Multiple hospitals within the Cleveland Clinic Health System. PATIENTS: Adult patients who met criteria for septic shock based on the U.S. Centers for Disease Control and Prevention Adult Sepsis Event definition. INTERVENTIONS: All patients received continuous infusion vasopressin as an adjunct to catecholamine vasopressors. MEASUREMENTS AND MAIN RESULTS: In total, 1,610 patients were included with a mean Acute Physiology and Chronic Health Evaluation III 109.0 ± 35.1 and Sequential Organ Failure Assessment 14.0 ± 3.5; 41% of patients survived the hospital admission. At the time of vasopressin initiation, patients had median (interquartile range) lactate concentration 3.9 mmol/L (2.3-7.2 mmol/L), norepinephrine-equivalent dose 25 µg/min (18-40 µg/min), and 5.3 hours (2.1-12.2 hr) elapsed since shock onset. The odds of in-hospital mortality increased 20.7% for every 10 µg/min increase in norepinephrine-equivalent dose up to 60 µg/min at the time of vasopressin initiation (adjusted odds ratio, 1.21 [95% CI, 1.09-1.34]), but no association was detected when the norepinephrine-equivalent dose exceeded 60 µg/min (adjusted odds ratio, 0.96 [95% CI, 0.84-1.10]). There was a significant interaction between timing of vasopressin initiation and lactate concentration (p = 0.02) for the association with in-hospital mortality. A linear association between increasing in-hospital mortality was detected for increasing lactate concentration at the time of vasopressin initiation, but no association was detected for time elapsed from shock onset. CONCLUSIONS: Higher norepinephrine-equivalent dose at vasopressin initiation and higher lactate concentration at vasopressin initiation were each associated higher in-hospital mortality in patients with septic shock who received vasopressin.

Hemodynamic Response to Vasopressin Dosage of 0.03 Units/Min vs. 0.04 Units/Min in Patients With Septic Shock.

BACKGROUND: Arginine vasopressin (AVP) is suggested as an adjunct to norepinephrine in patients with septic shock. Guidelines recommend an AVP dosage up to 0.03 units/min, but 0.04 units/min is commonly used in practice based on initial studies. This study was designed to compare the incidence of hemodynamic response between initial fixed-dosage AVP 0.03 units/min and AVP 0.04 units/min. METHODS: This retrospective, multi-hospital health system, cohort study included adult patients with septic shock receiving AVP as an adjunct to catecholamine vasopressors. Patients were excluded if they received an initial dosage other than 0.03 units/min or 0.04 units/min, or AVP was titrated within the first 6 hours of therapy. The primary outcome was hemodynamic response, defined as a mean arterial pressure ≥65 mm Hg and a decrease in catecholamine dosage at 6 hours after AVP initiation. Inverse probability of treatment weighting (IPTW) based on the propensity score for initial AVP dosage receipt was utilized to estimate adjusted exposure effects. RESULTS: Of the 1536 patients included in the observed data, there was a nearly even split between initial AVP dosage of 0.03 units/min (n = 842 [54.8%]) and 0.04 units/min (n = 694 [45.2%]). Observed patients receiving AVP 0.03 units/min were more frequently treated at the main campus academic medical center (96.3% vs. 52.2%, p < 0.01) and in a medical intensive care unit (87.4% vs. 39.8%, p < 0.01). The IPTW analysis included 1379 patients with achievement of baseline covariate balance. There was no evidence for a difference between groups in the incidence of hemodynamic response (0.03 units/min 50.0% vs. 0.04 units/min 53.1%, adjusted relative risk 1.06 [95% CI 0.94, 1.20]). CONCLUSIONS: Initial AVP dosing varied by hospital and unit type. Although commonly used, an initial AVP dosage of 0.04 units/min was not associated with a higher incidence of early hemodynamic response to AVP in patients with septic shock.

Genomic evolution and chemoresistance in germ-cell tumours.

Germ-cell tumours (GCTs) are derived from germ cells and occur most frequently in the testes. GCTs are histologically heterogeneous and distinctly curable with chemotherapy. Gains of chromosome arm 12p and aneuploidy are nearly universal in GCTs, but specific somatic genomic features driving tumour initiation, chemosensitivity and progression are incompletely characterized. Here, using clinical whole-exome and transcriptome sequencing of precursor, primary (testicular and mediastinal) and chemoresistant metastatic human GCTs, we show that the primary somatic feature of GCTs is highly recurrent chromosome arm level amplifications and reciprocal deletions (reciprocal loss of heterozygosity), variations that are significantly enriched in GCTs compared to 19 other cancer types. These tumours also acquire KRAS mutations during the development from precursor to primary disease, and primary testicular GCTs (TGCTs) are uniformly wild type for TP53. In addition, by functional measurement of apoptotic signalling (BH3 profiling) of fresh tumour and adjacent tissue, we find that primary TGCTs have high mitochondrial priming that facilitates chemotherapy-induced apoptosis. Finally, by phylogenetic analysis of serial TGCTs that emerge with chemotherapy resistance, we show how TGCTs gain additional reciprocal loss of heterozygosity and that this is associated with loss of pluripotency markers (NANOG and POU5F1) in chemoresistant teratomas or transformed carcinomas. Our results demonstrate the distinct genomic features underlying the origins of this disease and associated with the chemosensitivity phenotype, as well as the rare progression to chemoresistance. These results identify the convergence of cancer genomics, mitochondrial priming and GCT evolution, and may provide insights into chemosensitivity and resistance in other cancers.

Reinfection Rates Among Patients Who Previously Tested Positive for Coronavirus Disease 2019: A Retrospective Cohort Study.

BACKGROUND: Protection afforded from prior disease among patients with coronavirus disease 2019 (COVID-19) infection is unknown. If infection provides substantial long-lasting immunity, it may be appropriate to reconsider vaccination distribution. METHODS: This retrospective cohort study of 1 health system included 150 325 patients tested for COVID-19 infection via polymerase chain reaction from 12 March 2020 to 30 August 2020. Testing performed up to 24 February 2021 in these patients was included. The main outcome was reinfection, defined as infection ≥90 days after initial testing. Secondary outcomes were symptomatic infection and protection of prior infection against reinfection. RESULTS: Of 150 325 patients, 8845 (5.9%) tested positive and 141 480 (94.1%) tested negative before 30 August. A total of 1278 (14.4%) positive patients were retested after 90 days, and 62 had possible reinfection. Of those, 31 (50%) were symptomatic. Of those with initial negative testing, 5449 (3.9%) were subsequently positive and 3191 of those (58.5%) were symptomatic. Protection offered from prior infection was 81.8% (95% confidence interval [CI], 76.6-85.8) and against symptomatic infection was 84.5% (95% CI, 77.9-89.1). This protection increased over time. CONCLUSIONS: Prior infection in patients with COVID-19 was highly protective against reinfection and symptomatic disease. This protection increased over time, suggesting that viral shedding or ongoing immune response may persist beyond 90 days and may not represent true reinfection. As vaccine supply is limited, patients with known history of COVID-19 could delay early vaccination to allow for the most vulnerable to access the vaccine and slow transmission.

Choosing Wisely For Critical Care: The Next Five.

OBJECTIVES: To formulate new "Choosing Wisely" for Critical Care recommendations that identify best practices to avoid waste and promote value while providing critical care. DATA SOURCES: Semistructured narrative literature review and quantitative survey assessments. STUDY SELECTION: English language publications that examined critical care practices in relation to reducing cost or waste. DATA EXTRACTION: Practices assessed to add no value to critical care were grouped by category. Taskforce assessment, modified Delphi consensus building, and quantitative survey analysis identified eight novel recommendations to avoid wasteful critical care practices. These were submitted to the Society of Critical Care Medicine membership for evaluation and ranking. DATA SYNTHESIS: Results from the quantitative Society of Critical Care Medicine membership survey identified the top scoring five of eight recommendations. These five highest ranked recommendations established Society of Critical Care Medicine's Next Five "Choosing" Wisely for Critical Care practices. CONCLUSIONS: Five new recommendations to reduce waste and enhance value in the practice of critical care address invasive devices, proactive liberation from mechanical ventilation, antibiotic stewardship, early mobilization, and providing goal-concordant care. These recommendations supplement the initial critical care recommendations from the "Choosing Wisely" campaign.

Mortality, Morbidity, and Costs After Implementation of a Vasopressin Guideline in Medical Intensive Care Patients With Septic Shock: An Interrupted Time Series Analysis.

Background: Vasopressin decreases vasopressor requirements in patients with septic shock. However, the optimal norepinephrine dose for initiation or cessation of vasopressin is unclear. Objective: Analyze monthly intensive care unit (ICU) mortality rates 1 year preimplementation and postimplementation of a guideline suggesting a norepinephrine dose of 50 µg/min or more for initiation of vasopressin and early cessation of vasopressin. Methods: This retrospective quasi-experimental study included adult patients with septic shock admitted to the medical ICU of a tertiary care medical center over 2 years. Time periods were evaluated with interrupted time series analysis. Results: A total of 1148 patients were included: 573 patients preguideline and 575 patients postguideline. Group characteristics were well balanced at baseline, except patients postguideline had higher sequential organ failure assessment scores. Postguideline, fewer patients were initiated on vasopressin (305 [53.2%] vs 217 [37.7%], absolute difference -15.5% [95% CI -21.2% to -9.8%]), and the norepinephrine dose at vasopressin initiation was higher (median 25 [interquartile range 18, 40] µg/min vs 40 [22, 52] µg/min; median difference 15 [95% CI 11 to 19] µg/min; P < 0.01). After guideline implementation, there was no evidence for a difference in ICU mortality rate slope (slope change 0.07% [95% CI -0.8% to 1.0%] per month; P 0.87), but the vasoactive cost level decreased by US$183 (95% CI -US$327 to -US$39) per patient immediately after implementation. Conclusion and Relevance: Implementation of a guideline suggesting a high norepinephrine dose threshold for vasopressin initiation and early vasopressin cessation in patients with septic shock appears to be safe and may decrease vasoactive costs.

Sulforaphane enriched transcriptome of lung mitochondrial energy metabolism and provided pulmonary injury protection via Nrf2 in mice.

Nrf2 is essential to antioxidant response element (ARE)-mediated host defense. Sulforaphane (SFN) is a phytochemical antioxidant known to affect multiple cellular targets including Nrf2-ARE pathway in chemoprevention. However, the role of SFN in non-malignant airway disorders remain unclear. To test if pre-activation of Nrf2-ARE signaling protects lungs from oxidant-induced acute injury, wild-type (Nrf2+/+) and Nrf2-deficient (Nrf2-/-) mice were given SFN orally or as standardized broccoli sprout extract diet (SBE) before hyperoxia or air exposure. Hyperoxia-induced pulmonary injury and oxidation indices were significantly reduced by SFN or SBE in Nrf2+/+ mice but not in Nrf2-/- mice. SFN upregulated a large cluster of basal lung genes that are involved in mitochondrial oxidative phosphorylation, energy metabolism, and cardiovascular protection only in Nrf2+/+ mice. Bioinformatic analysis elucidated ARE-like motifs on these genes. Transcript abundance of the mitochondrial machinery genes remained significantly higher after hyperoxia exposure in SFN-treated Nrf2+/+ mice than in SFN-treated Nrf2-/- mice. Nuclear factor-κB was suggested to be a central molecule in transcriptome networks affected by SFN. Minor improvement of hyperoxia-caused lung histopathology and neutrophilia by SFN in Nrf2-/- mice implies Nrf2-independent or alternate effector mechanisms. In conclusion, SFN is suggested to be as a preventive intervention in a preclinical model of acute lung injury by linking mitochondria and Nrf2. Administration of SFN alleviated acute lung injury-like pathogenesis in a Nrf2-dependent manner. Potential AREs in the SFN-inducible transcriptome for mitochondria bioenergetics provided a new insight into the downstream mechanisms of Nrf2-mediated pulmonary protection.

TSP1 and TSP2 deficiencies affect LOX protein distribution in the femoral diaphysis and pro-peptide removal in marrow-derived mesenchymal stem cells in vitro.

Thrombospondin-1 and 2 have each been implicated in collagen fibrillogenesis. We addressed the possibility that deficits in lysyl oxidase (LOX) contribute to the extracellular matrix (ECM) phenotype of TSP-deficient bone. We examined detergent insoluble (mature cross-linked) and soluble (newly secreted) ECM fractions prepared from diaphyseal cortical bone. Detergent-insoluble hydroxyproline content, an indicator of cross-linked collagen content and LOX function, was reduced in female TSP-deficient bones. In male diaphyses, only TSP2 deficiency affected insoluble hydroxyproline content. Western blot suggested that removal of the LOX-pro-peptide (LOPP), an indication of LOX activation, was not affected by TSP status. Instead, the distribution of pro-LOX and mature LOX between immature and mature ECM was altered by TSP-status. LOX was also examined in primary marrow-derived mesenchymal stem cells (MSC) treated with ascorbate. Relative LOPP levels were elevated compared to WT in MSC conditioned medium from female TSP-deficient mice. When cells were serum starved to limit LOX pro-peptide removal, pro-LOX levels were elevated in TSP2-/- cells compared to wild-type. This phenotype was associated with a transient increase in BMP1 levels in TSP2-/- conditioned medium. TSP2 was detected in bone tissue and osteoblast cell culture. TSP1 was only detected in insoluble ECM prepared from WT diaphyseal bone samples. Our data suggest that the trimeric thrombospondins contribute to bone matrix quality by regulating the distribution of pro and mature LOX between newly secreted, immature ECM and mature, cross-linked ECM.

Initiation of venovenous extracorporeal membrane oxygenation in a patient receiving induction chemotherapy for acute myelogenous leukemia.

BACKGROUND: Acute respiratory failure is a leading cause of intensive care unit admission in patients with hematological malignancies; it carries a mortality rate exceeding 50%. Venovenous extracorporeal membrane oxygenation use in patients with acute hematologic malignancies concurrently receiving induction chemotherapy is not well studied. CASE PRESENTATION: A 44-year-old male developed acute respiratory distress syndrome in the setting of newly diagnosed acute myelogenous leukemia. He underwent successful induction chemotherapy while on venovenous extracorporeal membrane oxygenation. His course was complicated by a devastating subarachnoid hemorrhage. Life support modalities were discontinued in accordance to the wishes of the family. CONCLUSION: There is a lack of data to guide use of induction chemotherapy in patients with acute hematologic malignancies requiring venovenous extracorporeal membrane oxygenation, particularly with regard to dosing, safety, and efficacy of chemotherapeutic agents. This case highlights a potential role of venovenous extracorporeal membrane oxygenation in select young acute myelogenous leukemia patients who might benefit from this intervention and warrants further research.

Inter-rater Agreement for Abstraction of the Early Management Bundle, Severe Sepsis/Septic Shock (SEP-1) Quality Measure in a Multi-Hospital Health System.

BACKGROUND: The Early Management Bundle, Severe Sepsis/Septic Shock (SEP-1) quality measure is complex to abstract, which may lead to discrepancies between abstractors. This study was designed to evaluate inter-rater agreement between abstractors at individual hospitals in a health system and a lead abstractor on abstraction elements and measure compliance for SEP-1. METHODS: Patient cases qualifying for abstraction for SEP-1 over a four-month period in 2016 were initially abstracted at a local hospital and then centrally by a lead abstractor. Abstraction results were retrospectively compared to determine inter-rater agreement. RESULTS: A total of 580 SEP-1 cases were abstracted locally and centrally. Each site contributed a median (interquartile range) of 63 (49, 86) cases. There was complete concordance of measure-related elements in 391 cases (67%) (inter-rater agreement: κ = 0.40, p < 0.01). The most common discrepancy (60 cases) was severe sepsis presentation time. There was a weak correlation between SEP-1 compliance adjudicated locally and centrally (r2 = 0.41, p < 0.01). The average change in monthly SEP-1 measure compliance at each site after central adjudication was a 1% increase but ranged from a 49% decrease to a 40% increase. CONCLUSIONS: Concordance on SEP-1 abstraction elements between local and expert adjudicators was fair, and SEP-1 performance varied considerably from initial site-reported performance. The detailed nature of SEP-1 can lead to unreliable abstraction, which may lead to inaccurate reporting of compliance with the measure and affect comparability of performance between hospitals. Abstraction by a dedicated team for SEP-1 can reduce variability and improve efficiency.

Phase 2 study of idelalisib and entospletinib: pneumonitis limits combination therapy in relapsed refractory CLL and NHL.

Although agents targeting B-cell receptor signaling have provided practice-changing results in relapsed chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL), they require prolonged administration and provide incomplete responses. Given synergistic preclinical activity with phosphatidylinositol 3-kinase δ and spleen tyrosine kinase inhibition, this phase 2 study evaluated the safety and efficacy of the combination of idelalisib and entospletinib. Eligible patients with relapsed or refractory CLL or NHL underwent intrapatient dose escalation with each agent. With a median treatment exposure of 10 weeks, 60% and 36% of patients with CLL or follicular lymphoma, respectively, achieved objective responses. However, the study was terminated early because of treatment-emergent pneumonitis in 18% of patients (severe in 11 of 12 cases). Although most patients recovered with supportive measures and systemic steroids, 2 fatalities occurred and were attributed to treatment-emergent pneumonitis. Increases of interferon-γ and interleukins 6, 7, and 8 occurred over time in patients who developed pneumonitis. Future studies of novel combinations should employ conservative designs that incorporate pharmacodynamics/biomarker monitoring. These investigations should also prospectively evaluate plasma cytokine/chemokine levels in an attempt to validate biomarkers predictive of response and toxicity. This trial was registered at www.clinicaltrials.gov as #NCT01796470.

Immune responses and long-term disease recurrence status after telomerase-based dendritic cell immunotherapy in patients with acute myeloid leukemia.

BACKGROUND: Telomerase activity in leukemic blasts frequently is increased among patients with high-risk acute myeloid leukemia (AML). In the current study, the authors evaluated the feasibility, safety, immunogenicity, and therapeutic potential of human telomerase reverse transcriptase (hTERT)-expressing autologous dendritic cells (hTERT-DCs) in adult patients with AML. METHODS: hTERT-DCs were produced from patient-specific leukapheresis, electroporated with an mRNA-encoding hTERT and a lysosomal-targeting sequence, and cryopreserved. A total of 22 patients with a median age of 58 years (range, 30-75 years) with intermediate-risk or high-risk AML in first or second complete remission (CR) were enrolled. hTERT-DCs were generated for 24 patients (73%). A median of 17 intradermal vaccinations (range, 6-32 intradermal vaccinations) containing 1×107 cells were administered as 6 weekly injections followed by 6 biweekly injections. A total of 21 patients (16 in first CR, 3 in second CR, and 2 with early disease recurrence) received hTERT-DCs. RESULTS: hTERT-DCs were well tolerated with no severe toxicities reported, with the exception of 1 patient who developed idiopathic thrombocytopenic purpura. Of the 19 patients receiving hTERT-DCs in CR, 11 patients (58%) developed hTERT-specific T-cell responses that primarily were targeted toward hTERT peptides with predicted low human leukocyte antigen (HLA)-binding affinities. With a median follow-up of 52 months, 58% of patients in CR (11 of 19 patients) were free of disease recurrence at the time of their last follow-up visit; 57% of the patients who were aged ≥60 years (4 of 7 patients) also were found to be free of disease recurrence at a median follow-up of 54 months. CONCLUSIONS: The generation of hTERT-DCs is feasible and vaccination with hTERT-DCs appears to be safe and may be associated with favorable recurrence-free survival. Cancer 2017;123:3061-72. © 2017 American Cancer Society.

Role of bronchoalveolar lavage in the diagnosis of acute exacerbations of idiopathic pulmonary fibrosis: a retrospective study.

BACKGROUND: It has been recognized that despite previous stability some patients with idiopathic pulmonary fibrosis (IPF) experience acute clinical deteriorations called acute exacerbations of idiopathic pulmonary fibrosis (AEX-IPF). We hypothesized that pulmonary infection can be excluded based on clinical and laboratory data and that bronchoscopy with BAL is not mandatory in the diagnostic work-up of suspected AEX-IPF. METHODS: In this retrospective study we identified patients with acute respiratory failure who were evaluated for AEX-IPF at the Cleveland Clinic between January 2002 and December 2011. Univariate and multivariate analysis were performed with predefined risk factors and final diagnosis of AEX-IPF and pulmonary infection. All tests were performed at a significance level of 0.05. RESULTS: A total of 77 patients met the study inclusion criteria. Of these patients 47 (61 %) were diagnosed with AEX-IPF. Bronchoscopy was more likely to be performed in patients who were on cytotoxic medications (p < 0.05). In most cases the diagnosis of AEX-IPF versus pulmonary infection was based on combination of other microbiological, clinical, radiologic data and clinical judgment. A total of 10 patients out of 14 (71 %) with a final diagnosis of pulmonary infection were on steroids on admission versus 21 out of 63 patients (33 %) with other final diagnosis (p = 0.024, OR 7.817, 95 % CI 1.31-46.64). CONCLUSIONS: Exclusion of infection in our IPF patient cohort was mostly based on factors other than diagnostic bronchoscopy with BAL. Based on our results we suggested an algorithm for management of IPF patients presenting with acute respiratory failure.

Peripheral Administration of Norepinephrine: A Prospective Observational Study.

BACKGROUND: Historically, norepinephrine has been administered through a central venous catheter (CVC) because of concerns about the risk of ischemic tissue injury if extravasation from a peripheral IV catheter (PIVC) occurs. Recently, several reports have suggested that peripheral administration of norepinephrine may be safe. RESEARCH QUESTION: Can a protocol for peripheral norepinephrine administration safely reduce the number of days a CVC is in use and frequency of CVC placement? STUDY DESIGN AND METHODS: This was a prospective observational cohort study conducted in the medical ICU at a quaternary care academic medical center. A protocol for peripheral norepinephrine administration was developed and implemented in the medical ICU at the study site. The protocol was recommended for use in patients who met prespecified criteria, but was used at the treating clinician's discretion. All adult patients admitted to the medical ICU receiving norepinephrine through a PIVC from February 2019 through June 2021 were included. RESULTS: The primary outcome was the number of days of CVC use that were avoided per patient, and the secondary safety outcomes included the incidence of extravasation events. Six hundred thirty-five patients received peripherally administered norepinephrine. The median number of CVC days avoided per patient was 1 (interquartile range, 0-2 days per patient). Of the 603 patients who received norepinephrine peripherally as the first norepinephrine exposure, 311 patients (51.6%) never required CVC insertion. Extravasation of norepinephrine occurred in 35 patients (75.8 events/1,000 d of PIVC infusion [95% CI, 52.8-105.4 events/1,000 d of PIVC infusion]). Most extravasations caused no or minimal tissue injury. No patient required surgical intervention. INTERPRETATION: This study suggests that implementing a protocol for peripheral administration of norepinephrine safely can avoid 1 CVC day in the average patient, with 51.6% of patients not requiring CVC insertion. No patient experienced significant ischemic tissue injury with the protocol used. These data support performance of a randomized, prospective, multicenter study to characterize the net benefits of peripheral norepinephrine administration compared with norepinephrine administration through a CVC.

Monocarboxylate transporters facilitate succinate uptake into brown adipocytes.

Uptake of circulating succinate by brown adipose tissue (BAT) and beige fat elevates whole-body energy expenditure, counteracts obesity and antagonizes systemic tissue inflammation in mice. The plasma membrane transporters that facilitate succinate uptake in these adipocytes remain undefined. Here we elucidate a mechanism underlying succinate import into BAT via monocarboxylate transporters (MCTs). We show that succinate transport is strongly dependent on the proportion that is present in the monocarboxylate form. MCTs facilitate monocarboxylate succinate uptake, which is promoted by alkalinization of the cytosol driven by adrenoreceptor stimulation. In brown adipocytes, we show that MCT1 primarily facilitates succinate import. In male mice, we show that both acute pharmacological inhibition of MCT1 and congenital depletion of MCT1 decrease succinate uptake into BAT and consequent catabolism. In sum, we define a mechanism of succinate uptake in BAT that underlies its protective activity in mouse models of metabolic disease.

Thrombospondin-2 facilitates assembly of a type-I collagen-rich matrix in marrow stromal cells undergoing osteoblastic differentiation.

We examined the effects of Thrombospondin-2 (TSP2) deficiency on assembly of collagenous extracellular matrix (ECM) by primary marrow-derived mesenchymal stromal cells (MSC) undergoing osteoblast differentiation in culture. After 30 d, wild-type cells had accumulated and mineralized a collagen-rich insoluble matrix, whereas the TSP2-null cultures contained markedly lower amounts of matrix collagen and displayed reduced mineral. Differences in matrix collagen were seen as early as day 9, at which time wild-type cultures contained more total collagen per cell than did TSP2-null cells. Collagen was unevenly distributed amongst different extracellular compartments in the two cell-types. Collagen levels in conditioned medium of wild-type cells were higher than those of TSP2-null cells, but were roughly equivalent in the acid-soluble, newly cross-linked matrixes. Conversely, the mature, cross-linked acid-insoluble matrix layer of wild-type cells contained about twice as much collagen as TSP2-null cell-derived matrix. Western blot analysis of type-I collagen in detergent-soluble and insoluble matrix fractions supported the premise that matrix collagen levels were reduced in TSP2-null MSC undergoing osteoblastic differentiation in vitro. Western blot and immunofluorescent analysis suggested that assembly of fibronectin into matrix was not affected by TSP2 deficiency. Instead, western blots of conditioned medium demonstrated a marked reduction in mature, fully processed type-I collagen in the absence of TSP2. Our data suggest that in the context of osteoblast differentiation, TSP2 promotes the assembly of a type-I collagen-rich matrix by facilitating pro-collagen processing.