Faculty Bibliography

Pancreatic ductal adenocarcinoma (PDAC) evolves a complex microenvironment comprised of multiple cell types, including pancreatic stellate cells (PSCs). Previous studies have demonstrated that stromal supply of alanine, lipids, and nucleotides supports the metabolism, growth, and therapeutic resistance of PDAC. Here we demonstrate that alanine crosstalk between PSCs and PDAC is orchestrated by the utilization of specific transporters. PSCs utilize SLC1A4 and other transporter(s) to rapidly exchange and maintain environmental alanine concentrations. Moreover, PDAC cells upregulate SLC38A2 to supply their increased alanine demand. Cells lacking SLC38A2 fail to concentrate intracellular alanine and undergo a profound metabolic crisis resulting in markedly impaired tumor growth. Our results demonstrate that stromal-cancer metabolic niches can form through differential transporter expression, creating unique therapeutic opportunities to target metabolic demands of cancer.

OBJECTIVE:Ischemic complications (including in the lower extremity, visceral, spinal, and pelvic territories) following standard endovascular aortic repair (EVAR) are well recognized but fortunately uncommon. The incidence of such complications following fenestrated and branched aortic repair (F/BEVAR) has not been well defined in the literature. The objective of this study was to compare the incidence of ischemic complications between EVAR and F/BEVAR and to elucidate potential risk factors for these complications. METHODS:We identified all patients who underwent EVAR from 2003 to 2017 or F/BEVAR from 2012 to 2017 in the national Vascular Quality Initiative database. We assessed differences in perioperative ischemic outcomes with methods including logistic regression and inverse probability of treatment propensity score weighting, using a composite endpoint of lower extremity ischemia, intestinal ischemia, stroke, or new dialysis as the primary endpoint. RESULTS:The data comprised 35,379 EVAR patients and 3374 F/BEVAR patients. F/BEVAR patients were more likely to be female, have had previous aneurysm repairs, and be deemed unfit for open aneurysm repair; they were less likely to have ruptured aneurysms; and they had higher estimated blood losses, contrast volumes, and fluoroscopy and procedure times. The incidence of any ischemic event (7.7% vs 2.2%) as well as the incidences of the component endpoints of lower extremity ischemia (2.3% vs 1.0%), intestinal ischemia (2.7% vs 0.7%), stroke (1.5% vs 0.3%), and new hemodialysis (3.1% vs 0.4%) were all significantly increased (all P < .001) in F/BEVAR compared with standard EVAR. After propensity adjustment, F/BEVAR conferred increased odds of any ischemic complication (1.8), intestinal ischemia (2.0), lower extremity ischemia (1.3), new hemodialysis (10.2), and stroke (2.3). CONCLUSIONS:Rates of lower extremity ischemia, intestinal ischemia, new dialysis, and stroke each range from 0% to 1% for standard EVAR and 1% to 3% for F/BEVAR. The incidence of perioperative ischemic complications following F/BEVAR is significantly increased compared to EVAR. The real-world data in this study should help guide decision-making for surgeons and patients as well as serve as one metric for progress in device and technique development. Improvements in ischemic complications may come from continued technology development such as smaller sheaths, improved imaging to decrease procedure time and contrast volume, embolic protection, and increased operator skill with wire and catheter manipulation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Genetic and genomic research has greatly advanced our understanding of heart disease. Yet, comprehensive, in-depth, quantitative maps of protein expression in hearts of living humans are still lacking. Using samples obtained during valve replacement surgery in patients with mitral valve prolapse (MVP), we set out to define inter-chamber differences, the intersect of proteomic data with genetic or genomic datasets, and the impact of left atrial dilation on the proteome of patients with no history of atrial fibrillation (AF). We collected biopsies from right atria (RA), left atria (LA) and left ventricle (LV) of seven male patients with mitral valve regurgitation with dilated LA but no history of AF. Biopsy samples were analyzed by high-resolution mass spectrometry (MS), where peptides were pre-fractionated by reverse phase high-pressure liquid chromatography prior to MS measurement on a Q-Exactive-HF Orbitrap instrument. We identified 7,314 proteins based on 130,728 peptides. Results were confirmed in an independent set of biopsies collected from three additional individuals. Comparative analysis against data from post-mortem samples showed enhanced quantitative power and confidence level in samples collected from living hearts. Our analysis, combined with data from genome wide association studies suggested candidate gene associations to MVP, identified higher abundance in ventricle for proteins associated with cardiomyopathies and revealed the dilated LA proteome, demonstrating differential representation of molecules previously associated with AF, in non-AF hearts. This is the largest dataset of cardiac protein expression from human samples collected in vivo. It provides a comprehensive resource that allows insight into molecular fingerprints of MVP and facilitates novel inferences between genomic data and disease mechanisms. We propose that over-representation of proteins in ventricle is consequent not to redundancy but to functional need, and conclude that changes in abundance of proteins known to associate with AF are not sufficient for arrhythmogenesis.

Cyclic nucleotide-gated (CNG) channels convert cyclic nucleotide (CN) binding and unbinding into electrical signals in sensory receptors and neurons. The molecular conformational changes underpinning ligand activation are largely undefined. We report both closed- and open-state atomic cryo-EM structures of a full-length Caenorhabditis elegans cyclic GMP-activated channel TAX-4, reconstituted in lipid nanodiscs. These structures, together with computational and functional analyses and a mutant channel structure, reveal a double-barrier hydrophobic gate formed by two S6 amino acids in the central cavity. cGMP binding produces global conformational changes that open the cavity gate located ~52 Å away but do not alter the structure of the selectivity filter-the commonly presumed activation gate. Our work provides mechanistic insights into the allosteric gating and regulation of CN-gated and nucleotide-modulated channels and CNG channel-related channelopathies.

PURPOSE/OBJECTIVE:The purpose of this study is to determine if the radiographic humerus union measurement (RHUM) is predictive of union in humeral shaft fractures treated nonoperatively. METHODS:All patients with long bone fracture nonunion presenting to a single surgeon were enrolled in a prospective registry. This registry was queried to identify patients with humeral shaft fractures treated nonoperatively and developed nonunion. The nonunion cohort was matched to a three to one gender- and age-matched control group that were treated nonoperatively for a humeral shaft fracture and achieved union. Two fellowship-trained orthopedic traumatologists blinded to eventual union scored radiographs obtained 12 weeks after injury using the RHUM. A binomial logistic regression determined the effect of the RHUM on the likelihood of developing union. RESULTS:Nine patients with humeral shaft fractures treated nonoperatively with radiographs 12 weeks after injury that developed nonunion were identified. These patients were matched to 27 controls. Logistic regression demonstrated the RHUM was a significant predictor of healing 12 weeks after humeral shaft fracture treated nonoperatively (p = 0.014, odds ratio 9.434, 95% CI for OR 1.586-56.098). All patients with RHUM below 7 went on to nonunion. All patients with RHUM above 8 healed. Three of seven patients (43%) with RHUM of 7 or 8 healed. CONCLUSION/CONCLUSIONS:The RHUM demonstrated an increased likelihood of achieving union 12 weeks after injury. Orthopedic surgeons can counsel patients that fractures with RHUM scores of 6 or below are in danger of developing nonunion and can target interventions appropriately.

BACKGROUND:A systematic review failed to identify any systemic therapy used in alopecia areata (AA) where use is supported by robust evidence from high quality randomized controlled trials (RCTs). OBJECTIVE:To produce an international consensus statement on the use and utility of various treatments for AA. METHODS:Fifty hair experts from 5 continents were invited to participate in a 3 round Delphi process. Agreement >66% was considered consensus. RESULTS:In the first round, consensus was achieved in 22 of 423 (5%) questions. Following a face-to-face meeting in round 3, overall, consensus was achieved for only 130 (33%) treatment specific questions. There was greater consensus for intralesional treatment of AA 19 (68%) followed by topical treatment 25 (43%). Consensus was achieved in 45 (36%) questions pertaining to systemic therapies in AA. The categories with the least consensus were phototherapy and non-prescription therapies. LIMITATIONS/CONCLUSIONS:The study included a comprehensive list of systemic treatments for AA, but not all treatments used. CONCLUSION/CONCLUSIONS:Despite divergent opinions amongst experts, consensus was achieved on a number of pertinent questions. The concluding statement also highlights areas where expert consensus is lacking and where an international patient registry could enable further research.

BACKGROUND: Internalizing a strong medical professional identity (PI) is a critical part of medical education. Recent studies of medical students have documented that students' PI, measured by the Professional Identity Essay (PIE), a reflective writing assessment of PI based on Kegan's theory of adult development and Bebeau's developmental model of PI, vary and are impacted by education. Little is known about the PI of exemplary professional physicians. We sought to: 1) describe the PI of physicians who exemplify the highest principles of the medical profession, and 2) evaluate NYU faculty identified as professional exemplars by peers to provide data and demonstrate clear role models for learners METHODS: We elicited nominations for professional exemplar physicians from NYU faculty, chief residents, and 4th-year students, using the definition of professionalism developed by Colby and Damon (1992). Participants were recruited after receiving at least 3 nominations; select participants who received 1 or 2 nominations were also recruited to diversify the participants in terms of specialty, years of practice, gender and race.We also used snowball techniques to get nominations fromstudy participants. After consenting, faculty received the 11-question PIE. We analyzed demographic data of nominated faculty and completed a content analysis of the PIE.
RESULT(S): 206 individual faculty were nominated at least one time by 70 community members. 32 individuals were recruited to the study; to date 22 have completed the PIE. The 206 nominees/22 participants represent: 34/12 specialties, average years in practice 17.6/23.8, range of years in practice 62 for nominees/44 for participants. We identified 3 primary themes through the content analysis: (1) Response to Expectations, "Everything. The profession demands everything.As much as this profession takes fromme, it is dwarfed by what I have received in return." (2) Response to Failure: "I fail to live up to expectations every day. Some days thismotivatesme, other days I disappoint myself." (3) Learning from Others: "I view teaching as integral to medical professionalism." There was a range of developmental levels in the responses with some focusing more on external rather than internal motivations: "I can say that the [malpractice] process for me was very threatening, emotionally consuming and had the potential to alter professional behavior in the wrong way."
CONCLUSION(S): Nominated faculty represented a diverse group with respect to PI. Many participants demonstrated great professionalism and a sense of internal PI in responses to the PIE questions, while others focused onmore externalmotivations to drive their professional behaviors. Further analysis is needed to define the qualities of a true exemplary professional. The range of responses of the exemplars can both serve as role models for learners and provide multiple pathways for learners and faculty to strengthen their own professional identities

Background - Mutations in the gene encoding the sodium channel Na_v1.5 cause various cardiac arrhythmias. This variety may arise from different determinants of Na_v1.5 expression between cardiomyocyte domains. At the lateral membrane and T-tubules, Na_v1.5 localization and function remain insufficiently characterized. Methods - We used novel single-molecule localization microscopy (SMLM) and computational modeling to define nanoscale features of Na_v1.5 localization and distribution at the lateral membrane (LM), the LM groove, and T-tubules (TT) in cardiomyocytes from wild-type (N = 3), dystrophin-deficient (mdx; N = 3) mice, and mice expressing C-terminally truncated Na_v1.5 (ΔSIV; N = 3). We moreover assessed TT sodium current by recording whole-cell sodium currents in control (N = 5) and detubulated (N = 5) wild-type cardiomyocytes. Results - We show that Na_v1.5 organizes as distinct clusters in the groove and T-tubules which density, distribution, and organization partially depend on SIV and dystrophin. We found that overall reduction in Na_v1.5 expression in mdx and ΔSIV cells results in a non-uniform re-distribution with Na_v1.5 being specifically reduced at the groove of ΔSIV and increased in T-tubules of mdx cardiomyocytes. A TT sodium current could however not be demonstrated. Conclusions - Na_v1.5 mutations may site-specifically affect Na_v1.5 localization and distribution at the lateral membrane and T-tubules, depending on site-specific interacting proteins. Future research efforts should elucidate the functional consequences of this redistribution.

The Global Vitiligo Foundation (GVF) hosted the 2^nd Biennial Vitiligo International Symposium (VIS), which was held at the Detroit Marriott at Renaissance Center in Detroit, Michigan, USA from November 9-10, 2018. The conference was opened by Iltefat H. Hamzavi (Detroit, Michigan, USA), President of the GVF and Co-Chair of the VIS and David M. Ozog (Detroit, Michigan, USA), C.S. Livingood Chair and Chairman of the Department of Dermatology of Henry Ford Hospital, Detroit, Michigan, USA. Henry W. Lim (Detroit, Michigan, USA), former President of the American Academy of Dermatology, Chair Emeritus of the Department of Dermatology of Henry Ford Hospital, and Co-Chair of the VIS, then presented highlights of the meeting. The meeting was organized around four plenary lectures, several diverse panel discussions, and workshops emphasizing vitiligo surgery and imaging.