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Introduction Asthma is acutely aggravated and chronically worsened by cigarette smoke (CS), as well as secondhand smoke exposure. In this regard, studies show significant differences between women vs. men in their response to the detrimental effects of CS, suggesting that female sex steroids (particularly estrogen) may be involved. Airway smooth muscle (ASM) cell proliferation and airway remodeling is a key feature of asthma and COPD. Surprisingly, there is little information regarding sex steroid effects on cigarette smoke‐induced changes of airway structure and function. In the current study, we hypothesize that estrogen interferes with CSE exposure‐induced proliferation, thereby contributing to airway smooth muscle remodeling. Methods and Results Human ASM tissues (epithelium‐denuded) and isolated ASM cells were from lung samples of patients with known smoking histories undergoing thoracic surgery for non‐infectious, focal pathology. Exposure of human ASM to cigarette smoke extract (CSE, Kentucky research cigarette 1RF4) 1%CSE or 2%CSE for 24h significantly increased ASM proliferation (proliferation assay: Cell Titer Aueous One, and Cyquant). Exposure of physiological concentrations of 17‐β‐estradiol (E 2, 1nM) did not alter ASM proliferation at baseline. Interestingly, E 2 pre‐treatment (1 h prior to CSE exposure) significantly reduced CSE‐induced human ASM proliferation. This was further confirmed by Western blot analysis for proliferative markers PCNA and Cyclin E. In addition, to explore the mechanistic bases of differential effects of E 2 on ASM proliferation under basal and CSE‐exposed conditions, the estrogen receptor profile in ASM tissue was screened in parallel for patients with and without smoking histories. Human ASM tissue from smokers samples showed substantial increased ERα and β expression compared to non‐smokers. Inhibition of ERα and β prevented the effects of estrogen on CSE‐induced increases in proliferation. Conclusions Collectively, estrogen exposure decreased human ASM proliferation induced by CSE. ER expression and signaling is enhanced in CSE induced inflamed ASM, with a potential beneficial role in reducing remodeling with CS exposure. These results will lay the foundation for examining the role of estrogen signaling in pathogenesis of cigarette smoke‐induced airway remodeling and possible sex based therapeutic targets in smoking‐related diseases. Support or Funding Information Supported by Flight Attendants Medical Research Institute (VS) and NIH R01 grant HL123494 (VS)

Introduction A disproportionate increase in ventilation relative to carbon dioxide output (V E /VCO 2 ) slope is a strong prognostic indicator in heart failure with reduced (HFrEF) or preserved ejection fraction (HFpEF) patients. Similarly, secondary pulmonary hypertension also poses a profound mortality risk in these patients. Exaggerated ventilation and pulmonary pressures appear to parallel one another during exercise in HF. However, an underlying pathophysiologic mechanism relating these two outcomes remains incompletely understood. Thus, the aim of this study was to determine associations between anatomical and physiologic metrics of ventilatory control and pulmonary pressures during exercise in HFrEF and HFpEF. Methods 32 HFpEF and 33 HFrEF (EF: 62±2 vs 22±1%; male: 17 and 31; age: 70±2 and 55±2 yrs; BMI: 34±1 and 28±1 kg/m 2 ; weight: 98±4 and 86±3 (all P <0.05), respectively, participated in cardiopulmonary exercise testing during right heart catheterization. Measures of pulmonary pressures included: systolic (PASP); diastolic (PADP); mean (mPAP); wedge (PCWP); pulse (PP); transpulmonary gradient (TPG). Partial pressure of arterial oxygen (PaO 2 ) and carbon dioxide (PaCO 2 ) were measured via radial arterial catheterization. Ventilation was measured continuously using a breath by breath metabolic measurement system. We calculated dead space to tidal volume [Vd/Vt=(V E ×PaCO 2 )‐(863×VCO 2 )/(V E ×PaCO 2 )] and Alveolar‐arterial oxygen gradient (A‐a)=PAO 2 ‐PaO 2 ; V E /VCO 2 slope=rest to peak exercise. Results At rest, pulmonary pressures did not differ between groups ( P >0.05); whereas Vd/Vt was lower in HFpEF vs HFrEF (0.42±0.02 vs 0.48±0.01, respectively, P =0.03). At peak exercise, HFpEF had higher PCWP (34.8±1.2 vs 30.2±1.5 mm Hg, P =0.02) and PADP (35.4±1.3 vs 29.8±1.6 mm Hg, P =0.02), but lower Vd/Vt (0.32±0.02 vs 0.38±0.01, P =0.03) and V E /VCO 2 slope (35.3±1.6 vs 43.5±2.0, P <0.01) vs HFrEF. At peak in HFpEF, Vd/Vt was related to PASP (r=0.40, P =0.03), PP (r=0.44, P =0.01), and TPG (r=0.53, P <0.01), and A‐a was related to PASP (r=0.43, P =0.01), PP (r=0.44, P =0.01), and TPG (r=0.46, P <0.01). At peak in HFrEF, Vd/Vt was related to PADP (r=0.41, P =0.02), and A‐a was related to PASP (r=0.43, P <0.01), PADP (r=0.42, P =0.01), and mPAP (r=0.44, P <0.01). There were no significant relationships between measures of pulmonary pressures and PaCO 2 . Remaining correlations between pulmonary pressures and anatomical or physiologic metrics of ventilatory control were negligible in both groups ( P >0.05). Conclusion These data suggest pulmonary pressures play a role in dead space ventilation during exercise in HF. Moreover, as suggested by the A‐a gradient, augmented pulmonary pressures may contribute to an exacerbation of ventilation/perfusion mismatch during exercise in both HFrEF and HFpEF patients. Support or Funding Information None

Background Neurophysiological coupling between ventilation and locomotor muscle group III/IV muscle afferent fibers during exercise is an important relationship that favorably influences ventilation in young healthy adults. In contrast, we have shown that group III/IV locomotor muscle afferents provoke aberrant ventilation in aging heart failure patients, which is suggested to be a primary effect of heart failure. However, there remains a limited understanding of the effect of aging in the absence of cardiovascular disease on the group III/IV muscle afferent pathway. Subsystolic circulatory occlusion to elicit venous distension has been suggested to stimulate locomotor muscle afferent neurologic feedback. The purpose of this study was to compare ventilatory responses in young vs aging healthy adults during submaximal constant‐load exercise with intermittent bilateral subsystolic occlusion of locomotor muscles. Methods Healthy adults completed 2 visits (10 young [YNG] vs 9 OLD; age 22±1 vs 66±3 yrs, BSA 1.8±0.1 vs 1.9±0.1 m 2 ; % predicted peak VO 2 99±7 vs 115±7 %; peak workload 188±16 vs 144±9 W, respectively; age and workload P <0.05). Visit 1: peak exercise ergometry test. Visit 2: constant‐load cycle ergometry at 30% peak workload (YNG=56±5 vs OLD=43±3 W, P <0.05) with the first 3 min without cuffing (0 mm Hg) and intermittent subsystolic bilateral thigh cuff inflations to 20, 40, 60, 80, or 100 mm Hg for 2 min (randomized), with 2 min deflation between occlusions thereafter. Minute ventilation (V E ), respiratory rate (RR), tidal volume (V T ), oxygen uptake (VO 2 ) indexed to weight, carbon dioxide output (VCO 2 ), respiratory exchange ratio (RER), V E /VCO 2 , and end tidal partial pressure CO 2 (P ET CO 2 ) were measured continuously via breath by breath system. Results At rest, V E , RR, V T , or RER did not differ in YNG vs OLD ( P >0.05); whereas VO 2 (6.3±0.3 vs 3.9±0.2 mL/kg/min) and VCO 2 (0.3±0.0 vs 0.2± 0.0 L/min) were higher in YNG vs OLD (respectively, P <0.05). During all exercise occlusions, V E was higher in YNG vs OLD, with the largest difference at 100 mm Hg (36.7±1.7 vs 30.2±1.6 L/min, respectively, P <0.05). However, the % change from rest to 0 mm Hg or each cuff occlusion resulted in no differences in YNG vs OLD for V E ( P >0.05). In contrast, in YNG vs OLD, the largest % change from 0 mm Hg to the cuff occlusion resulting in between group differences included V E (3.3±3.0 vs 17.3±3.6 at 80 mm Hg, P <0.05), VCO 2 (2.3±2.3 vs 20.8±3.4 at 100 mm Hg, P <0.05) and V E /VCO 2 (7.0±2.6 vs 0.5±1.8 at 100 mm Hg, P <0.05). In addition, there was a trend for significant differences between YNG and OLD for V T (−1.2±4.4 vs 5.9±4.1 % at 80 mm Hg, P =0.15), VO 2 (−2.1±1.5 vs 3.3±1.8 %, at 100 mm Hg, P =0.09) and P ET CO 2 (−6.4±1.9 vs −2.3±1.4 % at 100 mm Hg, P =0.11). Conclusions These data suggest that aging is associated with altered ventilatory responses to venous occlusion of locomotor muscles during constant load submaximal exercise. These changes may be a result of an increased contribution of locomotor muscle afferents on ventilatory control with aging. Support or Funding Information none

BACKGROUND Enterochromaffin (EC) cells are enteroendocrine cells in the gastrointestinal (GI) epithelium that release serotonin (5‐HT) in response to a variety of stimuli including mechanical force. In turn, EC cell 5‐HT affects GI secretion, motility and sensation. The molecular mechanism of EC cell mechanotransduction is unknown. The recently discovered mechanosensitive ion channel Piezo2 is important in several mechanosensory cell types. AIM to determine if the mechanosensitive ion channel Piezo2 is expressed and functional in EC cells. METHODS Murine small bowel was collected, fixed in 4% paraformaldehyde, and frozen. Human and mouse RNA from human jejunum and mouse duodenum, jejunum and ileum was analyzed by quantitative RT‐PCR for Piezo2 mRNA. Piezo2 and 5‐HT were also identified by fluorescence immunolabeling. QGP‐1, a human enteroendocrine cell model, was analyzed by RT‐PCR for the presence of Piezo2 and immunolabeling was done to detect Piezo2 and 5‐HT. Piezo2 mechanically activated currents were recorded from QGP‐1 cells in whole‐cell configuration. Voltage‐clamped QGP‐1 cells were subjected to a series of mechanical perturbations using a piezo‐electrically driven glass probe at steps of 0.3 μm for stimulation. RESULTS Human jejunum and all segments of mouse small bowel mucosa (duodenum, jejunum, ileum) expressed Piezo2 mRNA. In human jejunum and all segments of mouse small bowel Piezo2 co‐localized with 5‐HT in >90% of 5‐HT containing cells. No Piezo2 immunoreactivity was seen outside of 5‐HT positive enterochromaffin cells. The enteroendocrine cell model QGP‐1 expressed both Piezo2 and 5‐HT by immunohistochemistry and RT‐PCR showed message for Piezo2. Application of force to the surface of voltage‐clamped QGP‐1 cells elicited whole cell fast inward non‐selective cation currents of ~200 pA (at −60 mV) that were blocked by Gd 3+ with kinetic properties compatible with Piezo2 channels. CONCLUSIONS Piezo2 is specifically expressed in human and murine small bowel EC cells and in the enteroendocrine cell model QGP‐1. QGP‐1 cells have a mechanosensitive inward cation current with kinetic and pharmacological properties similar to Piezo2. Our data suggest that Piezo2 is involved in EC cell mechanotransduction. Support or Funding Information Supported by NIH DK106456 , DK84567, DK052766

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder associated with chronic abdominal pain along with recurrent diarrhea, constipation, or both that afflicts millions of people worldwide. Currently, the etiological foundation of the disorder remains enigmatic. However, there is mounting evidence suggesting that serotonin may play a critical role in the pathophysiology of IBS. DNA microarrays analyzing the transcriptomes of 11 IBS patients versus 13 asymptomatic control patients have identified a series of 858 differentially‐expressed genes that may characterize the IBS pathological state. Gene ontology (GO) analysis of this subset of genes revealed that nodes featuring serotonin‐related pathways displayed the highest number of functions relative to other GO groups. Quantitative real‐time polymerase chain reaction (qRT‐PCR) analysis of IBS patient‐derived RNA displayed reduced expression of the rate‐limiting enzyme of the serotonin biosynthetic pathway, tryptophan hydroxylase 1 (TPH1), relative to a pool of RNA comprised of eight control patients. Further, this analysis revealed potential compensatory regulation of several other genes integral to the maintenance of serotonin metabolism. In addition, concentrations of serum 25‐hydroxyvitamin D in both the IBS and control sampled populations indicated a trend towards decreased vitamin D levels within the IBS cohort, regardless of IBS subtype. Finally, vitamin D was shown to be effective in regulating the expression of several key serotonin metabolism genes, alluding to a potential link between vitamin D and serotonin pathways modulating IBS. These findings suggest that the pathogenesis of IBS may be associated with abnormal serotonin metabolism and/or vitamin D deficiency, and provide novel insight into possible treatment regimes. Support or Funding Information Wisconsin Network for Health Research

Medical error is an important cause of patient morbidity/mortality. Disclosing medical errors to patients is an important component of safe practice. There is a growing need to assess the inherent nature of how physicians in training approach such unanticipated outcomes. With limited exposure for medical students to the idea of medical error disclosure, which is an important area of professionalism in medicine, we believe that a reflective writing exercise can be an efficient tool to objectively assess how students acknowledge and address medical errors early in their medical career. Every year, students in the 1 st year gross anatomy course are asked to respond to a scenario in which a medical student's cellular phone conversation with a friend in a public area (i.e. post office) was overheard by a family member of a cadaver donor to Mayo Medical School. Students were asked to write an apology email to the offended party (Mrs. X) as though they were the student who made the mistake. Students were given 48 hours to complete and submit the assignment. We retrospectively reviewed the medical error disclosure assignment of medical students in the first‐year gross anatomy course at Mayo Medical School between 2005 and 2015. An instrument for assessing medical error disclosure, consisting of fifteen items evaluated on Likert scale (1–5, 1 is the lowest and 5 is the highest), was developed. Using this evaluation tool, we assessed the basic elements of medical error disclosure – acknowledgement of error/system failure, expression of regret, awareness of its impact, description of future behavior, and proper tone as an apology letter. Preliminary data from years 2005, 2008, 2011, and 2014 indicated the mean error disclosure scores of 3.49 ± 0.83, 3.32 ± 0.81, 3.29 ± 0.84, and 3.25 ± 0.75, respectively. The word count in those four class years were 246.9 ± 84.0, 236.3 ± 86.4, 211.2 ± 92.3, and 242.3 ± 79.1 words, respectively. The proportion of students who claimed to have spoken with his/her mother was 2 out of 42 (4.7%), 4 out of 49 (8.2%), 0 out of 48 (0%), and 20 out of 51 (39%) students, respectively. Across the four class years, there was a non‐significant but uniform trend of reduced mean error disclosure score over time, while the mean word count did not show a certain pattern. One notable trend over the class years was an increasing attribution to their mother as the person they spoke with, possibly a way to help alleviate Mrs. X's frustration by eliciting empathy. Overall, this efficient, integrated writing exercise serves as a sensitive tool to objectively gauge skills in the basic areas of medical error disclosure in a preclinical anatomy course. Support or Funding Information My sponsor is Dr. Wojciech Pawlina, the senior author of the abstract. Funding will be considered by the Department of Anatomy, Mayo Clinic College of Medicine, Rochester, MN.

While small group learning and team‐based learning (TBL) have become widely accepted modalities in medical education, surprisingly little is known about how medical students interact between and within their learning teams and how dissection teams themselves interact with faculty or teaching assistants (TAs). This study sought to examine: (1) interactions between faculty/TAs and student teams; and (2) student table‐to‐table interactions taking place in the anatomy didactic block at Mayo Medical School. In addition, interactions between students in the same student team and overall team dynamics were examined by faculty. The purpose of this study is to understand dissection group dynamics and how these sets of interactions relate to student academic performance . The amount of time faculty/TAs spent with a group during each teaching session was recorded by students at the end of each session. The number of team‐to‐team interactions were also recorded. These values were then compared to student examination performance. Results from this study indicated that the individual time faculty/TAs spend with teams and the number of table‐to‐table interactions appeared to have no correlation with overall team academic performance. However, faculty assessment of interactions within student teams and overall team dynamics appears to be an accurate predictor of the team's overall academic performance, where groups with well‐defined leadership roles and strong cooperation between team members performed higher than those where this was not present . Support or Funding Information Mayo Clinic College of Medicine Department of Anatomy

Hypothermia/Rewarming (H/R) induces myocardial dysfunction although the underlying intracellular mechanisms remain elusive. We hypothesized that in cardiomyocytes, H/R disrupts intracellular Ca 2+ ([Ca 2+ ] cyt ) homeostasis via an effect on both release and clearance of cytosolic Ca 2+ leading to a prolongation of evoked [Ca 2+ ] cyt transients associated with activation with downstream impact on contractility. To test this hypothesis, isolated rat cardiomyocytes (13–15 cells from 6 rats per group) were loaded with the Ca 2+ indicator, Fura‐2AM (0.5 μM), and exposed to H/R with or without electrical pacing at 0.5 Hz. In both groups, evoked [Ca 2+ ] cyt and contractile (sarcomere length (SL) shortening) responses were simultaneously measured at 35°C before and after hypothermia using an IonOptix system. H/R experiments were conducted as follows: experimental temperature was cooled from 35°C to 15°C in 30 min, maintained at 15°C for 2 h, and then rewarmed back to 35°C in 30 min. Time‐matched controls were implemented for 3 h at 35°C. With electrical pacing throughout hypothermia, basal [Ca 2+ ] cyt increased and the kinetics of the evoked [Ca 2+ ] cyt responses were prolonged. In addition, the extent and velocity of SL shortening was reduced in cardiomyocytes that were paced during hypothermia. In contrast, in cardiomyocytes that were not electrically paced during hypothermia, basal [Ca 2+ ] cyt was maintained and the kinetics of evoked [Ca 2+ ] cyt transients were unaffected. In addition, in the absence of pacing during hypothermia, contractility of cardiomyocytes was unaffected. These results suggest that H/R affects the release and clearance of evoked [Ca 2+ ] cyt transients (e.g., RyR mediated Ca 2+ release and SERCA mediated clearance) such that basal [Ca 2+ ] cyt increases. This effect of H/R on [Ca 2+ ] cyt homeostasis is associated with reduced cardiac contractility.

Background Obstructive sleep apnea (OSA) is characterized by repetitive intermittent hypoxia and reoxygenation during sleep, and is a risk factor for cardiometabolic diseases including hypertension and diabetes. The renin‐angiotensin system (RAS) is an important cardiovascular and metabolic regulator playing key roles via angiotensin peptides. Recent studies demonstrate that all components of the RAS, including enzymes responsible for AngII generation, such as angiotensin converting enzyme (ACE) and chymase, are present in adipose tissue. Furthermore adipose tissue significantly contributes to systemic levels of AngII, thereby potentiating development of hypertension in obesity. Given that OSA patients are mostly obese, the localized effects of RAS in adipose tissue are likely an important mediator of OSA‐related hypertension. This study sought to investigate the effects of intermittent hypoxia (IH), a hallmark of OSA, on Ang II generation pathways in preadipocytes. Methods/Results RAS plays an important role in adipose tissue via its action on preadipocytes. Therefore, we examined the effects of IH in primary cultures of human white preadipocytes (HWP). HWP cells were exposed to repeated cycles of 30 min‐21% O 2 (normoxic) and 30 min‐1% O 2 (hypoxic) at 37°C for 24 hours. Cells grown in continuous normoxic conditions were used as controls. mRNA and protein expression of ACE, chymase, renin, AT1, and AT2 receptors were investigated by semi‐quantitative RT‐PCR and Western blot, respectively. Ang II secretion was examined by enzyme‐linked immunosorbent assay in condition medium. Results IH upregulated ACE (P=0.04) and chymase (P=0.05) expression while the expression of renin (P=0.94), AT1R (P=0.30), and AT2R (P=0.58) receptors did not change in HWP. Additionally, IH increased Ang II secretion in conditioned media (P=0.01). Conclusions This is the first study to demonstrate intermittent hypoxia‐mediated upregulation of Ang II generating enzymes ACE and chymase, along with increased AngII secretion in HWP. Together, our data strongly support the role of IH in upregulating RAS via increases in AngII. These studies suggest a role for adipose tissue and RAS in OSA related pathophysiology. Support or Funding Information NIH R01 grant (#HL65176); Becari C. is supported by grant from CNPq‐Brazil (# 203802/2014‐4).

There is evidence that the anabolic response to exercise is blunted in skeletal muscle in older adults. Older adults also exhibit reduced mitochondrial content and lower oxidative capacity. Since mitochondria provide chemical energy for muscle protein synthesis, it is possible that age‐related changes to mitochondrial physiology may contribute to anabolic resistance. We evaluated this possibility by measuring mitochondrial function and anabolic responses to exercise in 12 young (19–34 yrs) and 12 older (67–83 yrs) adults. Serial vastus lateralis biopsies were collected during an infusion of 13 C 6 phenylalanine to measure muscle protein synthesis at baseline and 16 hours after a single bout of unaccustomed resistance exercise (unilateral knee extension, 8 sets, 10 repetitions at 70% of 1‐repetition maximum). Real‐time PCR and RNA sequencing were used to evaluate the transcriptional response to acute exercise in muscle tissue. Respiratory capacity of isolated mitochondria was measured by high‐resolution respirometry. Mitochondrial respiratory capacity was significantly lower in older adults (4.67±0.47 pmol/s/ug) compared to young (6.60±0.70 pmol/s/ug, p=0.024). Postabsorptive protein synthesis rates were similar in young and old for mixed muscle (Y: 0.067±0.005 %/hr, O: 0.104±0.030 %/hr, p=0.13), mitochondrial (Y: 0.076±0.014 %/hr, O: 0.089±0.017 %/hr, p=0.58), and myofibrillar fractions (Y: 0.073±0.005 %/hr, O: 0.072±0.015 %/hr, p=0.94). Exercise increased protein synthesis similarly in young and old for mixed muscle (Fold changes Y: 1.45±0.16, O: 1.46±0.18, p=0.98), mitochondrial (Y: 0.90±0.28, O: 1.74±0.41, p=0.11), and myofibrillar (Y: 1.35±0.13, O: 1.37±0.18, p=0.93). These data demonstrate older adults have lower mitochondrial respiratory capacity yet exhibit similar anabolic responses to resistance exercise compared to young. Protein synthesis does not appear limited by the decreased mitochondrial capacity with age.