Farzad Moazed

Naive T Cell Recruitment to Nonlymphoid Tissues: A Role for Endothelium-Expressed CC Chemokine Ligand 21 in Autoimmune Disease and Lymphoid Neogenesis

Naive T cells are usually excluded from nonlymphoid tissues. Only when such tertiary tissues are subjected to chronic inflammation, such as in some (but not all) autoimmune diseases, are naive T cells recruited to these sites. We show that the CCR7 ligand CC chemokine ligand (CCL)21 is sufficient for attracting naive T cells into tertiary organs. We performed intravital microscopy of cremaster muscle venules in T-GFP mice, in which naive T cells express green fluorescent protein (GFP). GFP+ cells underwent selectin-dependent rolling, but no firm adherence (sticking). Superfusion with CCL21, but not CXC chemokine ligand 12, induced integrin-dependent sticking of GFP+ cells. Moreover, CCL21 rapidly elicited accumulation of naive T cells into sterile s.c. air pouches. Interestingly, a second CCR7 ligand, CCL19, triggered T cell sticking in cremaster muscle venules, but failed to induce extravasation in air pouches. Immunohistochemistry studies implicate ectopic expression of CCL21 as a mechanism for naive T cell traffic in human autoimmune diseases. Most blood vessels in tissue samples from patients with rheumatoid arthritis (85 ± 10%) and ulcerative colitis (66 ± 1%) expressed CCL21, and many perivascular CD45RA+ naive T cells were found in these tissues, but not in psoriasis, where CCL21+ vessels were rare (17 ± 1%). These results identify endothelial CCL21 expression as an important determinant for naive T cell migration to tertiary tissues, and suggest the CCL21/CCR7 pathway as a therapeutic target in diseases that are associated with naive T cell recruitment.

Glucose Phosphorylation and Mitochondrial Binding Are Required for the Protective Effects of Hexokinases I and II

ABSTRACT Alterations in glucose metabolism have been demonstrated for diverse disorders ranging from heart disease to cancer. The first step in glucose metabolism is carried out by the hexokinase (HK) family of enzymes. HKI and II can bind to mitochondria through their N-terminal hydrophobic regions, and their overexpression in tissue culture protects against cell death. In order to determine the relative contributions of mitochondrial binding and glucose-phosphorylating activities of HKs to their overall protective effects, we expressed full-length HKI and HKII, their truncated proteins lacking the mitochondrial binding domains, and catalytically inactive proteins in tissue culture. The overexpression of full-length proteins resulted in protection against cell death, decreased levels of reactive oxygen species, and possibly inhibited mitochondrial permeability transition in response to H2O2. However, the truncated and mutant proteins exerted only partial effects. Similar results were obtained with primary neonatal rat cardiomyocytes. The HK proteins also resulted in an increase in the phosphorylation of voltage-dependent anion channel (VDAC) through a protein kinase Cε (PKCε)-dependent pathway. These results suggest that both glucose phosphorylation and mitochondrial binding contribute to the protective effects of HKI and HKII, possibly through VDAC phosphorylation by PKCε.

Prompting physicians to address a daily checklist and process of care and clinical outcomes: A single-site study

RATIONALE Checklists may reduce errors of omission for critically ill patients. OBJECTIVES To determine whether prompting to use a checklist improves process of care and clinical outcomes. METHODS We conducted a cohort study in the medical intensive care unit (MICU) of a tertiary care university hospital. Patients admitted to either of two independent MICU teams were included. Intervention team physicians were prompted to address six parameters from a daily rounding checklist if overlooked during morning work rounds. The second team (control) used the identical checklist without prompting. MEASUREMENTS AND MAIN RESULTS One hundred and forty prompted group patients were compared with 125 control and 1,283 preintervention patients. Compared with control, prompting increased median ventilator-free duration, decreased empirical antibiotic and central venous catheter duration, and increased rates of deep vein thrombosis and stress ulcer prophylaxis. Prompted group patients had lower risk-adjusted ICU mortality compared with the control group (odds ratio, 0.36; 95% confidence interval, 0.13-0.96; P = 0.041) and lower hospital mortality compared with the control group (10.0 vs. 20.8%; P = 0.014), which remained significant after risk adjustment (odds ratio, 0.34; 95% confidence interval, 0.15-0.76; P = 0.008). Observed-to-predicted ICU length of stay was lower in the prompted group compared with control (0.59 vs. 0.87; P = 0.02). Checklist availability alone did not improve mortality or length of stay compared with preintervention patients. CONCLUSIONS In this single-site, preliminary study, checklist-based prompting improved multiple processes of care, and may have improved mortality and length of stay, compared with a stand-alone checklist. The manner in which checklists are implemented is of great consequence in the care of critically ill patients.

Making july safer: Simulation-based mastery learning during intern boot camp

Purpose Patient care quality worsens during academic year turnover. Incoming interns’ uneven clinical skills likely contribute to this phenomenon, known as the “July effect.” The aim of this study was to evaluate the impact of a simulation-based mastery learning (SBML) boot camp on internal medicine interns’ clinical skills. Method This was a cohort study of an SBML intervention at Northwestern University. In 2011, 47 interns completed boot camp; 109 interns (from 2009 and 2010) who did not participate in boot camp were historical controls. Boot-camp-trained interns participated in three days of small-group teaching sessions, deliberate practice, and individualized feedback. Primary outcome measures were performance of boot-camp-trained interns and historical controls on five parts of a clinical skills examination (CSE). Assessments included recognition of physical examination findings (cardiac auscultation), performance of procedures (paracentesis and lumbar puncture), management of critically ill patients (intensive care unit skills), and communication with patients (code status discussion). Boot camp participants were required to meet or exceed a minimum passing standard (MPS) before beginning their internship. Results Boot-camp-trained interns all eventually met or exceeded the MPS and performed significantly better than historical control interns on all skills (P < .01), even after controlling for age, gender, and USMLE Step 1 and 2 scores (P < .001). The authors detected no relationship between CSE scores and age, gender, prior experience, self-confidence, or USMLE Step 1 and 2 scores. Conclusions An SBML boot camp allows for individualized training, assessment, and documentation of competence before interns begin providing medical care.

Pulmonary toxicity of e-cigarettes

Electronic cigarettes (e-cigarettes or e-cigs) are designed to heat and aerosolize mixtures of vegetable glycerin, propylene glycol, nicotine, and flavoring additives, thus delivering nicotine by inhalation in the absence of combustion. These devices were originally developed to facilitate smoking cessation and have been available in the United States for over a decade. Since 2010, e-cig use has expanded rapidly, especially among adolescents, despite a paucity of short- and long-term safety data. Patterns of use have shifted to include never smokers and many dual users of e-cigs and combustible tobacco products. Over the last several years, research into the potential toxicities of e-cig aerosols has grown exponentially. In the interim, regulatory policymakers across the world have struggled with how to regulate an increasingly diverse array of suppliers and products, against a backdrop of strong advocacy from users, manufacturers, and tobacco control experts. Herein we provide an updated review of the pulmonary toxicity profile of these devices, summarizing evidence from cell culture, animal models, and human subjects. We highlight the major gaps in our current understanding, emphasize the challenges confronting the scientific and regulatory communities, and identify areas that require more research in this important and rapidly evolving field.

Bronchoalveolar lavage amylase is associated with risk factors for aspiration and predicts bacterial pneumonia.

Objectives:Aspiration of oropharyngeal or gastric contents into the respiratory tract leads to a spectrum of disorders with high morbidity. Aspiration is a diagnostic dilemma, because clinical characteristics and diagnostic tests are not effective predicting or confirming aspiration. We sought to determine whether &agr;-amylase, a protein secreted by salivary glands and the pancreas, is elevated in bronchoalveolar lavage specimens in patients with clinical risk factors for aspiration and whether bronchoalveolar lavage amylase predicts bacterial pneumonia. Design:Retrospective analysis. Setting:Five adult ICUs at a tertiary care urban medical center. Patients:Mechanically ventilated patients who underwent either bronchoscopic or nonbronchoscopic bronchoalveolar lavage within 72 hrs of endotracheal intubation between August 1, 2008 and June 30, 2010. Measurements and Main Results:A total of 296 bronchoalveolar lavage amylase results from 280 patients were included in the analysis, and 155 bronchoalveolar lavage amylase specimens were obtained from patients with at least one predefined preintubation risk factor (altered consciousness, swallowing dysfunction, difficult intubation, peri-intubation vomiting, or cardiac arrest). Bronchoalveolar lavage amylase concentration increased as the number of preintubation risk factors increased (p < 0.001). In addition, bronchoalveolar lavage amylase was elevated in patients with bacterial pneumonia (cfu/mL ≥ 104) (p < 0.001). The area under the receiver operator curve for the ability of bronchoalveolar lavage amylase to differentiate between positive and negative bronchoalveolar lavage culture was 0.67 (95% confidence interval, 0.60–0.75). The lower 95% confidence interval for bronchoalveolar lavage amylase in patients with at least one preintubation risk factor for aspiration was 125.9 units/L. In multivariate analysis, bronchoalveolar lavage amylase < 125 units/L was associated with significantly lower odds of bacterial pneumonia (odds ratio 0.39, 95% confidence interval 0.21–0.71, p = 0.002). Conclusions:Elevated bronchoalveolar lavage amylase is associated with risk factors for aspiration and may predict bacterial pneumonia. Bronchoalveolar lavage amylase may be useful as an early screening tool to guide management of patients suspected of aspiration.

Progress toward improving medical school graduates' skills via a "boot camp" curriculum.

Introduction Medical school graduates are expected to possess a broad array of clinical skills. However, concerns have been raised regarding the preparation of medical students to enter graduate medical education. We designed a simulation-based “boot camp” experience for students entering internal medicine residency and compared medical student performance with the performance of historical controls who did not complete boot camp. Methods This was a cohort study of a simulation-based boot camp educational intervention. Twenty medical students completed 2 days (16 hours) of small group simulation-based education and individualized feedback and skills assessment. Skills included (a) physical examination techniques (cardiac auscultation); technical procedures including (b) paracentesis and (c) lumbar puncture; (d) recognition and management of patients with life-threatening conditions (intensive care unit clinical skills/mechanical ventilation); and (e) communication with patients and families (code status discussion). Student posttest scores were compared with baseline scores of postgraduate year 1 (PGY-1) historical controls to assess the effectiveness of the intervention. Results Boot camp–trained medical students performed significantly better than PGY-1 historical controls on each simulated skill (P < 0.01). Results remained significant after controlling for age, sex, and US Medical Licensing Examination step 1 and 2 scores (P < 0.001). Conclusions A 2-day simulation-based boot camp for graduating medical students boosted a variety of clinical skills to levels significantly higher than PGY-1 historical controls. Simulation-based education shows promise to help ensure that medical school graduates are prepared to begin postgraduate training.

Retention of critical care skills after simulation-based mastery learning.

BACKGROUND Whether cognitive and patient care skills attained during simulation-based mastery learning (SBML) are retained is largely unknown. OBJECTIVE We studied retention of intensive care unit (ICU) clinical skills after an SBML boot camp experience. METHODS Forty-seven postgraduate year (PGY)-1 residents completed SBML intervention designed to increase procedural, communication, and patient care skills. The intervention included ICU skills such as ventilator and hemodynamic parameter management. Residents were required to meet or exceed a minimum passing score (MPS) on a clinical skills examination before starting actual patient care. Skill retention was assessed in 42 residents who rotated in the medical ICU. Residents received a standardized 15-minute booster teaching session reviewing key concepts during the first week of the rotation. During the fourth week of their rotation, PGY-1 residents completed a clinical skills examination at the bedside of an actual ICU patient. Group mean examination scores and the proportion of subjects who met or exceeded the MPS at each testing occasion were compared. RESULTS Residents scored a mean 90% (SD  =  6.5%) on the simulated skills examination immediately after training. Residents retained skills obtained through SBML as the mean score at bedside follow-up testing was 89% (SD  =  8.9%, P  =  .36). Thirty-seven of 42 (88%) PGY-1 residents met or exceeded the MPS at follow-up. CONCLUSION SBML leads to substantial retention of critical care knowledge, and patient care skills PGY-1 boot camp is a highly efficient and effective model that can be administered at the beginning of the academic year.

Code status discussion skill retention in internal medicine residents: one-year follow-up.

BACKGROUND Communicating with patients about goals of care is an important skill for internal medicine residents. However, many trainees are not competent to perform a code status discussion (CSD). A multimodality intervention improved skills in a group of first-year residents in 2011. How long these acquired CSD skills are retained is unknown. OBJECTIVE To study CSD skill retention one year after a multimodality intervention. DESIGN This was a longitudinal cohort study. SETTING/SUBJECTS Thirty-eight second-year internal medicine residents in a university-affiliated internal medicine residency program participated in the study. Nineteen completed the intervention and 19 served as controls. MEASUREMENTS Mean CSD clinical skills examination (CSE) scores using an 18-item checklist were compared after the intervention (2011) and one year later (2012). RESULTS Intervention group residents performed significantly better than residents in the control group (71.9% (standard deviation [SD]=16.0%) versus 54.7% (SD=17.1%; p<0.001) at one-year follow-up. Intervention group residents retained their CSD skills at one year as performance was 75.1% in 2011 and 71.9% in 2012 (p=0.46). Control group residents did not develop additional CSD skills as 2011 checklist performance was 53.2% and 2012 performance was 54.7% (p=0.78). CONCLUSIONS CSD skills taught in a rigorous curriculum are retained at one-year follow-up. Residents in the control group did not acquire new CSD skills despite an additional year of training and clinical experience. Further study is needed to link improved CSD skills to better patient care quality.

Cigarette smokers have exaggerated alveolar barrier disruption in response to lipopolysaccharide inhalation

Rationale Cigarette smoke exposure is associated with an increased risk of the acute respiratory distress syndrome (ARDS); however, the mechanisms underlying this relationship remain largely unknown. Objective To assess pathways of lung injury and inflammation in smokers and non-smokers with and without lipopolysaccharide (LPS) inhalation using established biomarkers. Methods We measured plasma and bronchoalveolar lavage (BAL) biomarkers of inflammation and lung injury in smokers and non-smokers in two distinct cohorts of healthy volunteers, one unstimulated (n=20) and one undergoing 50 μg LPS inhalation (n=30). Measurements and main results After LPS inhalation, cigarette smokers had increased alveolar-capillary membrane permeability as measured by BAL total protein, compared with non-smokers (median 274 vs 208 μg/mL, p=0.04). Smokers had exaggerated inflammation compared with non-smokers, with increased BAL interleukin-1β (p=0.002), neutrophils (p=0.02), plasma interleukin-8 (p=0.003), and plasma matrix metalloproteinase-8 (p=0.006). Alveolar epithelial injury after LPS was more severe in smokers than non-smokers, with increased plasma (p=0.04) and decreased BAL (p=0.02) surfactant protein D. Finally, smokers had decreased BAL vascular endothelial growth factor (VEGF) (p<0.0001) with increased soluble VEGF receptor-1 (p=0.0001). Conclusions Cigarette smoke exposure may predispose to ARDS through an abnormal response to a ‘second hit,’ with increased alveolar-capillary membrane permeability, exaggerated inflammation, increased epithelial injury and endothelial dysfunction. LPS inhalation may serve as a useful experimental model for evaluation of the acute pulmonary effects of existing and new tobacco products.