Faculty Bibliography

Magnetic Resonance Imaging (MRI) resolution continues to improve, making it important to understand the cellular basis for different MRI contrast mechanisms. Manganese-enhanced MRI (MEMRI) produces layer-specific contrast throughout the brain enabling in vivo visualization of cellular cytoarchitecture, particularly in the cerebellum. Due to the unique geometry of the cerebellum, especially near the midline, 2D MEMRI images can be acquired from a relatively thick slice by averaging through areas of uniform morphology and cytoarchitecture to produce very high-resolution visualization of sagittal planes. In such images, MEMRI hyperintensity is uniform in thickness throughout the anterior-posterior axis of sagittal sections and is centrally located in the cerebellar cortex. These signal features suggested that the Purkinje cell layer, which houses the cell bodies of the Purkinje cells and the Bergmann glia, is the source of hyperintensity. Despite this circumstantial evidence, the cellular source of MRI contrast has been difficult to define. In this study, we quantified the effects of selective ablation of Purkinje cells or Bergmann glia on cerebellar MEMRI signal to determine whether signal could be assigned to one cell type. We found that the Purkinje cells, not the Bergmann glia, are the primary of source of the enhancement in the Purkinje cell layer. This cell-ablation strategy should be useful for determining the cell specificity of other MRI contrast mechanisms.

The adhesion G-protein-coupled receptor GPR133 (ADGRD1) supports growth of the brain malignancy glioblastoma. How the extracellular interactome of GPR133 in glioblastoma modulates signaling remains unknown. Here, we use affinity proteomics to identify the transmembrane protein PTK7 as an extracellular binding partner of GPR133 in glioblastoma. PTK7 binds the autoproteolytically generated N-terminal fragment of GPR133 and its expression in trans increases GPR133 signaling. This effect requires the intramolecular cleavage of GPR133 and PTK7's anchoring in the plasma membrane. PTK7's allosteric action on GPR133 signaling is additive with but topographically distinct from orthosteric activation by soluble peptide mimicking the endogenous tethered Stachel agonist. GPR133 and PTK7 are expressed in adjacent cells in glioblastoma, where their knockdown phenocopies each other. We propose that this ligand-receptor interaction is relevant to the pathogenesis of glioblastoma and possibly other physiological processes in healthy tissues.

OBJECTIVE:To determine if a peri-operative pain cocktail injection improves post-operative pain, ambulation distance and long-term outcomes in hip fracture patients. DESIGN/METHODS:Prospective, single-blinded, randomized controlled trial. SETTING/METHODS:Academic Medical Center. PATIENTS/PARTICIPANTS/METHODS:Patients with OTA/AO 31A1-3 and 31B1-3 fractures undergoing operative fixation, excluding arthroplasty. INTERVENTION/METHODS:Multimodal local injection of bupivacaine (Marcaine), morphine sulfate (Duramorph), ketorolac (Toradol) given at the fracture site at the time of hip fracture surgery (Hip Fracture Injection, HiFI). MAIN OUTCOME MEASUREMENTS/METHODS:Patient-reported pain, American Pain Society Patient Outcome Questionnaire (APS-POQ), narcotic usage, length of stay, post-operative ambulation, Short Musculoskeletal Function Assessment (SMFA). RESULTS:75 patients were in the treatment group and 109 in the control group. Patients in the HiFI group had a significant reduction in pain and narcotic usage compared to the control group on post-operative day (POD) 0 (p<0.01). Based on the APS-POQ, patients in the control group had a significantly harder time falling asleep, staying asleep, and experienced increased drowsiness on POD 1 (p<0.01). Patient ambulation distance was greater on POD 2 (p<0.01) and POD 3 (p<0.05) in the HiFI group. The control group experienced more major complications (p<0.05). At six-weeks post-op, patients in the treatment group reported significantly less pain, better ambulatory function, less insomnia, less depression, and better satisfaction than the control group as measured by the APS-POQ. The SMFA bothersome index was also significantly lower for patients in the HiFI group, p<0.05. CONCLUSIONS:Intraoperative HiFI not only improved early pain management and increased ambulation in patients undergoing hip fracture surgery while in the hospital, it was also associated with early improved health related quality of life following discharge. LEVEL OF EVIDENCE/METHODS:Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

PURPOSE/OBJECTIVE:The purpose of this study is to compare medium to long term patient reported outcomes to one-year data for patients treated surgically for an aseptic fracture nonunion. METHODS:305 patients surgically treated for a fracture-nonunion were prospectively followed. Data collected included pain scores measured by the Visual Analog Scale (VAS), clinical outcomes assessed by the Short Musculoskeletal Functional Assessment (SMFA), and range of motion. 75% of patients in this study had lower extremity fracture nonunions and 25% had upper extremity fracture nonunions. Femur fracture nonunions were the most common. Data at latest follow-up was compared to one-year follow-up using the independent t-test. RESULTS:Sixty-two patients were available for follow-up data at an average of eight years. There were no differences in patient reported outcomes between one and eight years according to the standardized total SMFA (p = 0.982), functional index SMFA (p = 0.186), bothersome index SMFA (p = 0.396), activity index SMFA (p = 0.788), emotional index SMFA (p = 0.923), or mobility index SMFA (p = 0.649). There was also no difference in reported pain (p = 0.534). Range of motion data was collected for patients who followed up in clinic for an average of eight years after their surgical treatment. 58% of these patients reported a slight increase in range of motion at an average of eight years. CONCLUSION/CONCLUSIONS:Patient functional outcomes, range of motion, and reported pain all normalize after one year following surgical treatment for fracture nonunion and do not change significantly at an average of eight years. Surgeons can feel confident in counseling patients that their results will last and they do not need to follow up beyond one year, barring pain or other complications. LEVEL OF EVIDENCE/METHODS:Level IV.

Musculoskeletal development and later post-natal homeostasis are highly dynamic processes, marked by rapid structural and functional changes across very short periods of time. Adult anatomy and physiology are derived from pre-existing cellular and biochemical states. Consequently, these early developmental states guide and predict the future of the system as a whole. Tools have been developed to mark, trace, and follow specific cells and their progeny either from one developmental state to the next or between circumstances of health and disease. There are now many such technologies alongside a library of molecular markers which may be utilized in conjunction to allow for precise development of unique cell 'lineages'. In this review, we first describe the development of the musculoskeletal system beginning as an embryonic germ layer and at each of the key developmental stages that follow. We then discuss these structures in the context of adult tissues during homeostasis, injury, and repair. Special focus is given in each of these sections to the key genes involved which may serve as markers of lineage or later in post-natal tissues. We then finish with a technical assessment of lineage tracing and the techniques and technologies currently used to mark cells, tissues, and structures within the musculoskeletal system.

PURPOSE/OBJECTIVE:To determine the factors associated with discharge location in patients with hip fractures and whether home discharge was associated with a lower readmission and complication rate. METHODS:Hip fracture patients who presented to our academic medical center for operative management of a hip fracture were enrolled into an IRB-approved hip fracture database. Radiographs, demographics, and injury details were recorded at the time of presentation. Patients were grouped based upon discharge disposition: home (with or without home services), acute rehabilitation facility (ARF), or sub-acute rehabilitation facility (SAR). RESULTS:The cohorts differed in marital status, with a greater proportion of patients discharged to home being married (51.7% vs. 43.8% vs. 34.1%) (P < 0.05). Patients discharged to home were less likely to require an assistive device (P < 0.05). Patients discharged to home experienced fewer post-operative complications (P < 0.05) and had lower readmission rates (P < 0.05). Being married was associated with an increased likelihood of discharge to home (OR = 1.679, CI = 1.391-2.028, P < 0.001). Being enrolled in Medicare/Medicaid was associated with decreased odds of discharge to home (OR = 0.563, CI = 0.457-0.693, P < 0.001). Use of an assistive device was associated with decreased odds of discharge to home (OR = 0.398, CI = 0.326-0.468, P < 0.001). Increases in CCI (OR = 0.903, CI = 0.846-0.964, P = 0.002) and number of inpatient complications (OR = 0.708, CI = 0.532-0.943, P = 0.018) were associated with decreased odds of home discharge. CONCLUSION/CONCLUSIONS:Hip fracture patients discharged to home were healthier and more functional at baseline, and also less likely to have had a complicated hospital course. Those discharged to home also had lower rates of readmission and post-operative complications. LEVEL OF EVIDENCE/METHODS:III.

In CM238, 76% of patients (pts) with high-risk resected melanoma (MEL) treated with adjuvant NIVO were alive at 5 years, but there is limited RW data to validate these findings in a similar patient population. This study compared the OS of pts treated with adjuvant NIVO in CM238 vs. RW pts. Pts with stage III resected MEL (AJCC 8th edition) who received adjuvant NIVO were selected from CM238 and the nationwide Flatiron Health electronic health record-derived de-identified database (the RW cohort). Pts in the RW cohort were required to meet the eligibility criteria in CM238 where possible. OS/real-world OS (rwOS) were evaluated using Kaplan-Meier methods and compared using Cox proportional hazards models after adjusting for key prognostic baseline variables (age, sex, race, disease stage, time from surgical resection to index date, ECOG, and comorbidities) between the two cohorts. In the RW cohort, 492 pts with resected stage III MEL received adjuvant NIVO and 320 pts met the eligibility criteria of CM238. Compared with pts in the CM238 cohort, pts in the RW cohort were older (median: 64 vs. 56 years), heavier (91 vs. 82 kg), had a higher proportion of diabetes (9% vs. 6%) and ECOG PS 1 (17% vs. 10%), and had slightly more stage IIIA (4% vs. 1%), less stage IIIB (29% vs. 32%), and similar stage IIIC (63% vs. 63%) and stage IIID (4% vs. 5%). Before adjustment, pts in the RW cohort had a higher risk of mortality compared with pts in the CM238 cohort (HR: 1.46; 95% CI, 1.00 to 2.13; p < 0.05). After adjusting for differences in key patient characteristics, OS was similar between the two cohorts (HR: 1.12; 95% CI, 0.68 to 1.84, p = 0.66). In conclusion, pts with stage III resected MEL treated with adjuvant NIVO in the RW setting had OS similar to those in CM238 after adjusting for key prognostic factors

Small animal models have been a challenge for the study of SARS-CoV-2 transmission, with most investigators using golden hamsters or ferrets. Mice have the advantages of low cost, wide availability, less regulatory and husbandry challenges, and the existence of a versatile reagent and genetic toolbox. However, adult mice do not robustly transmit SARS-CoV-2. Here we establish a model based on neonatal mice that allows for transmission of clinical SARS-CoV-2 isolates. We characterize tropism, respiratory tract replication and transmission of ancestral WA-1 compared to variants Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), Omicron BA.1 and Omicron BQ.1.1. We identify inter-variant differences in timing and magnitude of infectious particle shedding from index mice, both of which shape transmission to contact mice. Furthermore, we characterize two recombinant SARS-CoV-2 lacking either the ORF6 or ORF8 host antagonists. The removal of ORF8 shifts viral replication towards the lower respiratory tract, resulting in significantly delayed and reduced transmission in our model. Our results demonstrate the potential of our neonatal mouse model to characterize viral and host determinants of SARS-CoV-2 transmission, while revealing a role for an accessory protein in this context.

BACKGROUND:(phosphatase and actin regulator 1) locus strongly correlate with coronary artery disease. However, the biological function of PHACTR1 remains poorly understood. Here, we identified the proatherosclerotic effect of endothelial PHACTR1, contrary to macrophage PHACTR1. METHODS: RESULTS:KO on EC activation and atherosclerosis in vivo. CONCLUSIONS:Our results identified endothelial PHACTR1 as a novel PPARγ corepressor to promote atherosclerosis in disturbed flow regions. Endothelial PHACTR1 is a potential therapeutic target for atherosclerosis treatment.

OBJECTIVES/OBJECTIVE:Obesity is characterized by local and systemic low-grade inflammatory responses. Adipose tissue macrophages (ATM) play decisive roles in inflammation, insulin signaling, and various metabolic dysfunctions. Diets enriched with ω-3 polyunsaturated fatty acids (PUFAs) have been shown to improve health and mitigate pathologic conditions. However, the effects of ω-3 PUFA on adipose tissue inflammation, ATM number, and phenotype are poorly defined in human obesity. The aim of this study was to examine differences in expression of metabolic-inflammatory markers in omental, mesenteric, and subcutaneous fat depots of obese women supplemented with ω-3 PUFAs for 4 wk compared with a low-calorie diet before bariatric surgery. METHODS:In a randomized controlled trial, inflammatory markers in the abdominal adipose tissue and the systemic response in obese women were studied. Patients were treated with a 2-wk low-calorie diet (LCD) or a 4-wk ω-3 PUFA-enriched diet (920 mg eicosapentaenoic acid, 760 mg docosahexaenoic acid daily) before laparoscopic bypass surgery. Omental, mesenteric, and subcutaneous adipose tissue biopsies were collected during surgery and analyzed for quantity and phenotype of ATMs, and profiled for adipokines, cytokines, and signal transduction molecules. RESULTS:The chronic inflammatory state characterized by ATM markers was mostly improved by ω-3 PUFAs in visceral adipose tissue. We observed a decreased expression of CD45, CCL2, and CD68, indicating a lower inflammatory state. In patients with type 2 diabetes, ω-3 PUFAs lowered the expression of Netrin-1. CONCLUSIONS:Compared with an LCD, a diet enriched with ω-3 PUFAs influences the inflammatory state in different adipose tissue depots, by affecting markers of adipose tissue inflammation, macrophage phenotype, and retention. However, this was not reflected in clinical parameters such as insulin resistance and inflammatory cytokines. Subcutaneous adipose tissue and visceral adipose tissue have different responses to an LCD or a ω-3 PUFA-enriched diet. The presence of diabetes modifies the expression of inflammatory markers.