Treating amyotrophic lateral sclerosis with allogeneic Schwann cell-derived exosomal vesicles: a case report.

Schwann cells are essential for the maintenance and function of motor neurons, axonal networks, and the neuromuscular junction. In amyotrophic lateral sclerosis, where motor neuron function is progressively lost, Schwann cell function may also be impaired. Recently, important signaling and potential trophic activities of Schwann cell-derived exosomal vesicles have been reported. This case report describes the treatment of a patient with advanced amyotrophic lateral sclerosis using serial intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles, marking, to our knowledge, the first instance of such treatment. An 81-year-old male patient presented with a 1.5-year history of rapidly progressive amyotrophic lateral sclerosis. After initial diagnosis, the patient underwent a combination of generic riluzole, sodium phenylbutyrate for the treatment of amyotrophic lateral sclerosis, and taurursodiol. The patient volunteered to participate in an FDA-approved single-patient expanded access treatment and received weekly intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles to potentially restore impaired Schwann cell and motor neuron function. We confirmed that cultured Schwann cells obtained from the amyotrophic lateral sclerosis patient via sural nerve biopsy appeared impaired (senescent) and that exposure of the patient's Schwann cells to allogeneic Schwann cell-derived exosomal vesicles, cultured expanded from a cadaver donor improved their growth capacity in vitro. After a period of observation lasting 10 weeks, during which amyotrophic lateral sclerosis Functional Rating Scale-Revised and pulmonary function were regularly monitored, the patient received weekly consecutive infusions of 1.54 × 10 12 (×2), and then consecutive infusions of 7.5 × 10 12 (×6) allogeneic Schwann cell-derived exosomal vesicles diluted in 40 mL of Dulbecco's phosphate-buffered saline. None of the infusions were associated with adverse events such as infusion reactions (allergic or otherwise) or changes in vital signs. Clinical lab serum neurofilament and cytokine levels measured prior to each infusion varied somewhat without a clear trend. A more sensitive in-house assay suggested possible inflammasome activation during the disease course. A trend for clinical stabilization was observed during the infusion period. Our study provides a novel approach to address impaired Schwann cells and possibly motor neuron function in patients with amyotrophic lateral sclerosis using allogeneic Schwann cell-derived exosomal vesicles. Initial findings suggest that this approach is safe.

Excision of Intra-articular Knee Heterotopic Ossification Using a 70° Arthroscope.

Heterotopic ossification is ectopic lamellar bone formation within soft tissue and can result in significant functional limitations. There are multiple underlying etiologies of HO including musculoskeletal trauma and traumatic brain injury. Intra-articular HO of the knee is rare and is typically located within the cruciate ligaments. We report a case of a 24-year-old female who presented with worsening right knee pain and limited knee extension two and a half years after a motor vehicle crash with multiple lower extremity fractures. Physical examination of the knee revealed anterior pain, limited extension, and a palpable infrapatellar prominence. Imaging showed a retropatellar tendon, intra-articular excrescence of bone proximal to the anterior tibial plateau. Diagnostic arthroscopy with a 70° arthroscope identified HO at the proximal anterior tibial plateau, which was excised with a high-speed burr under direct visualization. At the three-month follow-up, the patient remained asymptomatic and returned to sport. Retropatellar tendon, intra-articular anterior knee HO is a rare but debilitating clinical entity that can be successfully and safely managed with excision under direct visualization using a 70° arthroscope.

Histopathologic Features of Mucosal Head and Neck Cancer Cachexia.

Objective: Determine the histopathologic features that correlate with head and neck cancer (HNC) cachexia. Methods: A single-institution, retrospective study was performed on adults with HPV-negative, mucosal squamous cell carcinoma of the aerodigestive tract undergoing resection and free flap reconstruction from 2014 to 2019. Patients with distant metastases were excluded. Demographics, comorbidities, preoperative nutrition, and surgical pathology reports were collected. Comparisons of histopathologic features and cachexia severity were made. Results: The study included 222 predominantly male (64.9%) patients aged 61.3 ± 11.8 years. Cachexia was identified in 57.2% patients, and 18.5% were severe (≥15% weight loss). No differences in demographics were identified between the groups. Compared to control, patients with severe cachexia had lower serum hemoglobin (p=0.048) and albumin (p < 0.001), larger tumor diameter (p < 0.001), greater depth of invasion (p < 0.001), and elevated proportions of pT4 disease (p < 0.001), pN2-N3 disease (p=0.001), lymphovascular invasion (p=0.009), and extranodal extension (p=0.014). Multivariate logistic regression identified tumor size (OR [95% CI] = 1.36 [1.08-1.73]), oral cavity tumor (OR [95% CI] = 0.30 [0.11-0.84]), and nodal burden (OR [95% CI] = 1.16 [0.98-1.38]) as significant histopathologic contributors of cancer cachexia. Conclusions: Larger, more invasive tumors with nodal metastases and aggressive histologic features are associated with greater cachexia severity in mucosal HNC.

Publicly Available Anatomic Total Shoulder Arthroplasty Rehabilitation Protocols Show High Variability and Frequent Divergence from the 2020 ASSET Recommendations.

Background: In 2020, the American Society of Shoulder and Elbow Therapists (ASSET) published an evidence-based consensus statement outlining postoperative rehabilitation guidelines following anatomic total shoulder arthroplasty (TSA). Purpose: The purpose of this study was to (1) quantify the variability in online anatomic TSA rehabilitation protocols, and (2) assess their congruence with the ASSET consensus guidelines. Methods: This study was a cross-sectional investigation of publicly available, online rehabilitation protocols for anatomic TSA. A web-based search was conducted in April 2022 of publicly available rehabilitation protocols for TSA. Each collected protocol was independently reviewed by two authors to identify recommendations regarding immobilization, initiation, and progression of passive (PROM) and active range of motion (AROM), as well as the initiation and progression of strengthening and post-operative exercises and activities. The time to initiation of various components of rehabilitation was recorded as the time at which the activity or motion threshold was permitted by the protocol. Comparisons between ASSET start dates and mean start dates from included protocols were performed. Results: Of the 191 academic institutions included, 46 (24.08%) had publicly available protocols online, and a total of 91 unique protocols were included in the final analysis. There were large variations seen among included protocols for the duration and type of immobilization post-operatively, as well as for the initiation of early stretching, PROM, AROM, resistance exercises, and return to sport. Of the 37 recommendations reported by both the ASSET and included protocols, 31 (83.78%) were found to be significantly different between groups (p\<0.05). Conclusion: Considerable variability was found among online post-operative protocols for TSA with substantial deviation from the ASSET guidelines. These findings highlight the lack of standardization in rehabilitation protocols following anatomic TSA. Level of Evidence: 3b.

Single bundle hamstrings autograft preparation techniques for anterior cruciate ligament reconstruction: current concepts.

Anterior cruciate ligament reconstruction (ACLR) is one of the most common orthopedic procedures, and huge variation exists in the surgical technique. Single bundle hamstrings autograft reconstruction is a common method and has good clinical outcomes. A criticism of the hamstrings autograft is a small graft diameter, often less than 8-mm, which has been associated with increased re-rupture rates. Several graft preparation techniques for single bundle hamstrings autograft exist. Perioperative decisions include the number of tendons utilized, number of graft strands, graft configuration, and femoral and tibial fixation methods. Awareness of the minimum tendon and graft length required to produce each graft variation is necessary to avoid common pitfalls. However, intraoperative graft modification is possible to maximize graft diameter, and obtain proper fixation. The objective of this current concepts review is to describe the indications, surgical anatomy, technique, intraoperative tips, clinical outcomes, and complications for single bundle hamstrings autograft preparation techniques in ACLR.

Patterns and trends in melanoma mortality in the United States, 1999-2020.

INTRODUCTION: Melanoma, a deadly form of skin cancer, has witnessed a notable increase in incidence over the past decades. Despite advancements in treatment, it remains a significant cause of cancer mortality. Understanding demographic trends and variations in melanoma mortality is crucial for addressing disparities and implementing effective interventions. METHODS: Using the Centers for Disease Control Wide Ranging Online Data for Epidemiologic Research (CDC WONDER) database, we analyzed melanoma mortality data in the United States from 1999 to 2020. Data were stratified by demographic and regional variables, and age-adjusted mortality rates were calculated. Descriptive analysis was performed and Joinpoint regression analysis was employed to identify temporal trends. RESULTS: Between 1999 and 2020, there were 184,416 melanoma-related deaths in the United States Overall, the age-adjusted mortality rate declined from 2.7 to 2.0 per 100,000 people at a rate of -1.3% annually, with significant variations across demographic groups and regions. Men, non-Hispanic White individuals, and those aged > 65 experienced higher mortality rates. Non-Hispanic White individuals noted the steepest decrease in AAMR after 2013 at a rate of -6.1% annually. Disparities were seen by geographic density, with rural populations exhibiting higher mortality compared to their urban and suburban counterparts. CONCLUSION: The study highlights a significant reduction in melanoma mortality in the U.S. since 2013, potentially attributed to advancements in diagnostic techniques such as dermoscopy and the introduction of immune checkpoint inhibitors. Disparities persist, particularly among rural populations. Targeted interventions focusing on increased screening and education are warranted to further mitigate melanoma mortality and address demographic disparities.

Chaperones help TACkle phage infection.

Bacteria have evolved anti-viral defenses, but the mechanisms of sensing and stopping infection are still under investigation. In this issue of Cell Host & Microbe, Mets, Kurata, Ernits et al. describe how direct sensing of a phage protein by a bacterial toxin-antitoxin-associated chaperone unleashes toxin activity to prevent infection.

isolateR: an R package for generating microbial libraries from Sanger sequencing data.

MOTIVATION: Sanger sequencing of taxonomic marker genes (e.g., 16S/18S/ITS/rpoB/cpn60) represents the leading method for identifying a wide range of microorganisms including bacteria, archaea, and fungi. However, the manual processing of sequence data and limitations associated with conventional BLAST searches impede the efficient generation of strain libraries essential for cataloging microbial diversity and discovering novel species. RESULTS: isolateR addresses these challenges by implementing a standardized and scalable three-step pipeline that includes: 1) automated batch processing of Sanger sequence files, 2) taxonomic classification via global alignment to type strain databases in accordance with the latest international nomenclature standards, and 3) straightforward creation of strain libraries and handling of clonal isolates, with the ability to set customizable sequence dereplication thresholds and combine data from multiple sequencing runs into a single library. The tool's user-friendly design also features interactive HTML outputs that simplify data exploration and analysis. Additionally, in silico benchmarking done on two comprehensive human gut genome catalogues (IMGG and Hadza hunter-gather populations) showcase the proficiency of isolateR in uncovering and cataloging the nuanced spectrum of microbial diversity, advocating for a more targeted and granular exploration within individual hosts to achieve the highest strain-level resolution possible when generating culture collections. AVAILABILITY: isolateR is available at: https://github.com/bdaisley/isolateR. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Reporting of Participant Race and Ethnicity in Cerebrovascular Randomized Controlled Trials.

BACKGROUND: Randomized controlled trials (RCTs) provide information on appropriate management protocols in patients with cerebrovascular diseases. Despite growing evidence of race and ethnicity being independent predictors of outcomes, recent literature has drawn attention to inadequate reporting of these demographic profiles across RCTs. To our knowledge, the adherence to reporting race and/or ethnicity in cerebrovascular RCTs remains undescribed. Our study describes trends in the reporting of race and/or ethnicity across cerebrovascular RCTs. METHODS: Web of Science was searched to identify the top 100-cited cerebrovascular RCTs. Additional articles were retrieved from guidelines issued by the American Heart Association (AHA) for the management of ischemic stroke, intracerebral hemorrhage (ICH) and aneurysmal subarachnoid hemorrhage (aSAH). Univariate and multivariate analyses were performed to assess for factors influencing reporting of race/ ethnicity. RESULTS: 65% of cerebrovascular RCTs lacked reporting of participant race and/ or ethnicity. Multivariate regression revealed that studies from North America had a 14.74- fold higher odds (95% CI: 4.574- 47.519] of reporting race/ ethnicity. Impact factor of the journal was associated with a 1.007-fold odds of reporting race/ ethnicity [95% CI: 1.000- 1.013]. Reporting of race and/or ethnicity did not increase with time, or vary according to the number of participating centers, median number of study participants, source of funding or category of RCT. Among RCTs that reported race, Blacks and Asians were underrepresented compared to Whites. CONCLUSION: 65% of prominent cerebrovascular RCTs lack adequate reporting of participant race/ ethnicity. Reasons for inadequate reporting of these variables remain unclear and warrant additional investigation.

A Psychiatry Clerkship Orientation Based on Bite-Sized Teaching and Chalk Talks.

OBJECTIVE: Chalk talks are a subtype of bite-sized teaching with potential benefits over conventional teaching methods, including their use of visuals, adaptability, and potential to be more engaging. The objective of this study was to develop and evaluate the effectiveness of an orientation curriculum for medical students during the psychiatry clerkship based on bite-sized teaching and chalk talks. METHODS: A series of brief (10 min) lectures were developed covering fundamental skills in psychiatry, including psychiatric interview, mental status exam, and differential diagnosis. Talks were presented to medical students by the study author on the first day of their psychiatry clerkship in 60-min group educational sessions with 10-15 students per group. Data was gathered in pre- and post-session surveys that measured response to 4 knowledge-based questions on mental status exam terminology, 3 questions assessing confidence in completing skills associated with the talks, and 3 questions assessing beliefs regarding these skills. RESULTS: Fifty-six medical students participated in the educational sessions and completed pre- and post-session surveys. Students showed significant improvement from pre- to post-session in answering knowledge questions and perceived confidence in all skills, and indicated significant change in their beliefs regarding these topics. CONCLUSIONS: Although this is a small study without a control group, the results provide initial evidence that approaches to teaching foundational psychiatry topics based on bite-sized teaching and chalk talks may be an acceptable and more time-efficient alternative to a traditional lecture-based curriculum, and can produce significant changes in knowledge and attitudes.

IFN-γ production by functionally reprogrammed Treg cells promotes anti-tumor efficacy of OX40/CD137 bispecific agonist therapy.

Regulatory T (Treg) cells are highly enriched within many tumors and suppress immune responses to cancer. There is intense interest in reprogramming Treg cells to contribute to anti-tumor immunity. OX40 and CD137 are expressed highly on Treg cells, activated and memory T cells, and NK cells. Here, using a novel tetravalent bispecific antibody targeting mouse OX40 and CD137 (FS120m), we show that OX40/CD137 bispecific agonists induce potent anti-tumor immunity partially dependent upon IFN-γ-production by functionally reprogrammed Treg cells. Treatment of tumor-bearing animals with OX40/CD137 bispecific agonists reprograms Treg cells into both fragile Foxp3+ IFN-γ+ cells with decreased suppressive function, and lineage instable Foxp3- IFN-γ+ cells. Treg cell fragility is partially dependent upon IFN-γ signaling, whereas Treg cell instability is associated with reduced IL-2 signaling upon treatment with OX40/CD137 bispecific agonists. Importantly, conditional deletion of Ifng in Foxp3+ Treg cells and their progeny partially reverses the anti-tumor efficacy of OX40/CD137 bispecific agonist therapy, revealing that reprogramming of Treg cells into IFN-γ-producing cells contributes to the efficacy of OX40/CD137 bispecific agonists. These findings provide insights into mechanisms by which bispecific agonist therapies targeting co-stimulatory receptors highly expressed by Treg cells potentiate anti-tumor immunity in mouse models.

MHC heterozygosity limits T cell receptor variability in CD4 T cells.

αß T cell receptor (TCR) V(D)J genes code for billions of TCR combinations. However, only some appear on peripheral T cells in any individual because, to mature, thymocytes must react with low affinity but not high affinity with thymus expressed major histocompatibility (MHC)/peptides. MHC proteins are very polymorphic. Different alleles bind different peptides. Therefore, any individual might express many different MHC alleles to ensure that some peptides from an invader are bound to MHC and activate T cells. However, most individuals express limited numbers of MHC alleles. To explore this, we compared the TCR repertoires of naïve CD4 T cells in mice expressing one or two MHC alleles. Unexpectedly, the TCRs in heterozygotes were less diverse that those in the sum of their MHC homozygous relatives. Our results suggest that thymus negative selection cancels out the advantages of increased thymic positive selection in the MHC heterozygotes.

Intraspecific variation in crayfish behavioral traits affects leaf litter breakdown in streams.

Although intraspecific trait variation is increasingly recognized as affecting ecosystem processes, few studies have examined the ecological significance of among-population variation in behavioral traits in natural ecosystems. In freshwater habitats, crayfish are consumers that can influence ecosystem structure (e.g., macroinvertebrate communities) and function (e.g., leaf litter breakdown). To test whether crayfish behavioral traits (activity, boldness, and foraging voracity) are major contributors of leaf litter breakdown rates in the field, we collected rusty crayfish (Faxonius rusticus) from eight streams across the midwestern USA and measured behaviors using laboratory assays. At the same streams, we measured breakdown rates of leaf packs that were accessible or inaccessible to crayfish. Our results provide evidence that among-population variation in crayfish boldness and foraging voracity was a strong predictor of leaf litter breakdown rates, even after accounting for commonly appreciated environmental drivers (water temperature and human land use). Our results suggest that less bold rusty populations (i.e., emerged from shelter more slowly) had greater direct impacts on leaf litter breakdown than bold populations (P = 0.001, r2 = 0.85), potentially because leaf packs can be both a shelter and food resource to crayfish. Additionally, we found that foraging voracity was negatively related to breakdown rates in leaf packs that were inaccessible to crayfish (P = 0.025, r2 = 0.60), potentially due to a trophic cascade from crayfish preying on other invertebrates that consume leaf litter. Overall, our results add to the growing evidence that trait variation in animals may be important for understanding freshwater ecosystem functioning.

Gene expression differences associated with intrinsic hindfoot muscle loss in the jerboa, Jaculus jaculus.

Vertebrate animals that run or jump across sparsely vegetated habitats, such as horses and jerboas, have reduced the number of distal limb bones, and many have lost most or all distal limb muscle. We previously showed that nascent muscles are present in the jerboa hindfoot at birth and that these myofibers are rapidly and completely lost soon after by a process that shares features with pathological skeletal muscle atrophy. Here, we apply an intra- and interspecies differential RNA-Seq approach, comparing jerboa and mouse muscles, to identify gene expression differences associated with the initiation and progression of jerboa hindfoot muscle loss. We show evidence for reduced hepatocyte growth factor and fibroblast growth factor signaling and an imbalance in nitric oxide signaling; all are pathways that are necessary for skeletal muscle development and regeneration. We also find evidence for phagosome formation, which hints at how myofibers may be removed by autophagy or by nonprofessional phagocytes without evidence for cell death or immune cell activation. Last, we show significant overlap between genes associated with jerboa hindfoot muscle loss and genes that are differentially expressed in a variety of human muscle pathologies and rodent models of muscle loss disorders. All together, these data provide molecular insight into the process of evolutionary and developmental muscle loss in jerboa hindfeet.

Sexual health in transgender and gender diverse people.

PURPOSE OF REVIEW: Sexual health and sexual function are critical to the wellbeing of cisgender, transgender, and gender diverse populations. To date, there has been only limited patient-focused evaluation of sexual function in transgender and gender diverse patients at several stages in their gender-affirming medical care. There remains a need to better understand the impact of gender affirming medical and surgical therapy on sexual health, and to develop evidence-based treatments to address sexual dysfunction when present. RECENT FINDINGS: The impact of gender-affirming hormone therapy on sexual health is complex and evolves over time on treatment. Despite high incidences of complications, major genital gender-affirming surgeries such as vulvovaginoplasty and penile implant placement after phalloplasty yield high patient satisfaction. While treatments to preserve or restore erections and to improve vaginal lubrication have been trialed based upon literature in cisgender populations, there remains minimal evidence to guide medical treatment of sexual dysfunction ranging from erectile dysfunction to dyspareunia. SUMMARY: There is a continued need for ongoing efforts to develop patient-reported outcome measures and rigorous investigation of sexual health preservation and restoration treatments in transgender and gender diverse populations.

Fungal cryopreservation across 61 genera: Practical application and method evaluation.

Fungi occupy important environmental, cultural, and socioeconomic roles. However, biological research of this diverse kingdom has lagged behind that of other phylogenetic groups. This is partially the result of the notorious difficulty in culturing a diverse array of filamentous fungal species due to their (i) often unpredictable growth, (ii) unknown preferences for culturing conditions, and (iii) long incubation times compared with other microorganisms such as bacteria and yeasts. Given the complexity associated with concurrently culturing diverse fungal species, developing practical methods for preserving as many species as possible for future research is vital. The widely accepted best practice for preserving fungal tissue is the use of cryogenic biobanking at -165 C, allowing for the preservation and documentation of stable genetic lineages, thus enabling long-term diversity-centered research. Despite the extensive literature on fungal cryopreservation, substantial barriers remain for implementation of cryogenic biobanks in smaller mycological laboratories. In this work, we present practical considerations for the establishment of a fungal culture biobank, as well as provide evidence for the viability of 61 fungal genera in cryogenic storage. By providing a pragmatic methodology for cryogenically preserving and managing many filamentous fungi, we show that creating a biobank can be economical for independently owned and operated mycology laboratories, which can serve as a long-term resource for biodiversity, conservation, and strain maintenance.

Same-visit hepatitis C testing and treatment to accelerate cure among people who inject drugs (the QuickStart Study): a cluster randomised cross-over trial protocol.

INTRODUCTION: Despite universal access to government-funded direct-acting antivirals (DAAs) in 2016, the rate of hepatitis C treatment uptake in Australia has declined substantially. Most hepatitis C is related to injecting drug use; reducing the hepatitis C burden among people who inject drugs (PWID) is, therefore, paramount to reach hepatitis C elimination targets. Increasing DAA uptake by PWID is important for interrupting transmission and reducing incidence, as well as reducing morbidity and mortality and improving quality of life of PWID and meeting Australia's hepatitis C elimination targets. METHODS AND ANALYSIS: A cluster randomised cross-over trial will be conducted with three intervention arms and a control arm. Arm A will receive rapid hepatitis C virus (HCV) antibody testing; arm B will receive rapid HCV antibody and rapid RNA testing; arm C will receive rapid HCV antibody testing and same-day treatment initiation for HCV antibody-positive participants; the control arm will receive standard of care. The primary outcomes will be (a) the proportion of participants with HCV commencing treatment and (b) the proportion of participants with HCV achieving cure. Analyses will be conducted on an intention-to-treat basis with mixed-effects logistic regression models. ETHICS AND DISSEMINATION: The study has been approved by the Alfred Ethics Committee (number HREC/64731/Alfred-2020-217547). Each participant will provide written informed consent. Reportable adverse events will be reported to the reviewing ethics committee. The findings will be presented at scientific conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT05016609. TRIAL PROGRESSION: The study commenced recruitment on 9 March 2022 and is expected to complete recruitment in December 2024.

Why does one trust? A 360-degree perspective on the role of position power in weighting trustworthiness factors.

The purpose of the current paper is to explore the influence of the perceived trustworthiness factors of ability, benevolence and integrity on general and specific trust across supervisors, subordinates and peers with the same focal referent. This study used a 360-degree approach to examine how positional power asymmetries influence the relationship between trustworthiness and trust for a general and situation-specific referent. Data were obtained from military supervisors (N = 200), peers (N = 123), and subordinates (N = 85). Measures of trustworthiness and trust of a common military officer were obtained. Supervisors and subordinates differed in their relative weighting of trustworthiness factors (i.e. ability, benevolence, and integrity) when evaluating general and specific trust. Peers evidenced no difference in the relative weighting of trustworthiness factors. The relationship between benevolence and specific trust was stronger for subordinates than for supervisors. One implication of our findings is that trust can develop differently in bottom-up versus top-down organizational relationships. This study provides evidence that supervisors and subordinates emphasize different aspects of trustworthiness when evaluating their trust of a focal officer, and this process was different for general versus specific trust referents. The study also extends previous research by replicating previous findings across raters.

Responding to the workforce crisis: consensus recommendations from the Second Workforce Summit of the American Society of Pediatric Nephrology.

IMPORTANCE: Pediatric patients with complex medical problems benefit from pediatric sub-specialty care; however, a significant proportion of children live greater than 80 mi. away from pediatric sub-specialty care. OBJECTIVE: To identify current knowledge gaps and outline concrete next steps to make progress on issues that have persistently challenged the pediatric nephrology workforce. EVIDENCE REVIEW: Workforce Summit 2.0 employed the round table format and methodology for consensus building using adapted Delphi principles. Content domains were identified via input from the ASPN Workforce Committee, the ASPN's 2023 Strategic Plan survey, the ASPN's Pediatric Nephrology Division Directors survey, and ongoing feedback from ASPN members. Working groups met prior to the Summit to conduct an organized literature review and establish key questions to be addressed. The Summit was held in-person in November 2023. During the Summit, work groups presented their preliminary findings, and the at-large group developed the key action statements and future directions. FINDINGS: A holistic appraisal of the effort required to cover inpatient and outpatient sub-specialty care will help define faculty effort and time distribution. Most pediatric nephrologists practice in academic settings, so work beyond clinical care including education, research, advocacy, and administrative/service tasks may form a substantial amount of a faculty member's time and effort. An academic relative value unit (RVU) may assist in creating a more inclusive assessment of their contributions to their academic practice. Pediatric sub-specialties, such as nephrology, contribute to the clinical mission and care of their institutions beyond their direct billable RVUs. Advocacy throughout the field of pediatrics is necessary in order for reimbursement of pediatric sub-specialist care to accurately reflect the time and effort required to address complex care needs. Flexible, individualized training pathways may improve recruitment into sub-specialty fields such as nephrology. CONCLUSIONS AND RELEVANCE: The workforce crisis facing the pediatric nephrology field is echoed throughout many pediatric sub-specialties. Efforts to improve recruitment, retention, and reimbursement are necessary to improve the care delivered to pediatric patients.

NMR structures of small molecules bound to a model of an RNA CUG repeat expansion.

Trinucleotide repeat expansions fold into long, stable hairpins and cause a variety of incurable RNA gain-of-function diseases such as Huntington's disease, the myotonic dystrophies, and spinocerebellar ataxias. One approach for treating these diseases is to bind small molecules to the structured RNAs. Both Huntington's disease-like 2 (HDL2) and myotonic dystrophy type 1 (DM1) are caused by a r(CUG) repeat expansion, or r(CUG)exp. The RNA folds into a hairpin structure with a periodic array of 1×1 nucleotide UU loops (5'CUG/3'GUC; where the underlined nucleotides indicate the Us in the internal loop) that sequester various RNA-binding proteins (RBP) and hence the source of its gain-of-function. Here, we report NMR-refined structures of single 5'CUG/3'GUC motifs in complex with three different small molecules, a di-guandinobenzoate (1), a derivative of 1 where the guanidino groups have been exchanged for imidazole (2), and a quinoline with improved drug-like properties (3). These structures were determined using nuclear magnetic resonance (NMR) spectroscopy and simulated annealing with restrained molecular dynamics (MD). Compounds 1, 2, and 3 formed stacking and hydrogen bonding interactions with the 5'CUG/3'GUC motif. Compound 3 also formed van der Waals interactions with the internal loop. The global structure of each RNA-small molecule complexes retains an A-form conformation, while the internal loops are still dynamic but to a lesser extent compared to the unbound form. These results aid our understanding of ligand-RNA interactions and enable structure-based design of small molecules with improved binding affinity for and biological activity against r(CUG)exp. As the first ever reported structures of RNA r(CUG) repeats bound to ligands, these structures can enable virtual screening campaigns combined with machine learning assisted de novo design.