Citations

Abstract Background Mono-allelic Dehydrodolichyl Diphosphate Synthase ( DHDDS) variants are associated with juvenile Parkinsonism, developmental delay and seizures. Symptoms are progressive, and various mechanisms, such as defective glycosylation, lysosomal dysfunction and cholesterol accumulation have been hypothesized to underlie disease symptoms. There is no treatment for DHDDS-related disease. Methods Patient-derived cortical forebrain organoids were created to elucidate disease mechanisms and evaluate potential treatments. In these neuronal models, glycosylation, lipidomics, proteomics, cholesterol/ganglioside accumulation, mitochondrial function and electrophysiological activity were assessed. Finally, we investigated the effects of nicotinamide mononucleotide (NMN), identified through a yeast-based drug screen, in neuronal cell models and in six patients in an off-label, N-of-1, observational series. Results DHDDS-patient derived organoids showed visual signs of degeneration after four months of culturing. This was accompanied by significant cholesterol accumulation in astrocytes, decreased mitochondrial respiration and loss of deep-layer neurons. In addition, we identified glycosylation abnormalities, showing for the first time that glycosylation in human tissue is affected by monoallelic DHDDS variants. Proteomic analysis revealed altered protein expression of proteins involved in lipid metabolism, cytoskeletal organization and neuronal development. We found that oral Nicotinamide Mononucleotide supplementation led to significant improvement in mitochondrial respiration and electrophysiological parameters in organoids, concurring with clinical improvements in all of the treated patients, particularly regarding their ataxia and tremor. Conclusion Our findings reveal a progressive phenotype in DHDDS-patient-derived brain organoids, with mitochondrial dysfunction and astrocyte-specific metabolic alterations contributing to disease pathology. Notably, NMN treatment led to clinical improvements in patients with heterozygous DHDDS variants, highlighting its potential as a therapeutic strategy.

e16486 Background: Allele-specific KRAS G12C inhibitors have revolutionized lung and colorectal cancer treatment, yet the biology of G12C in other gastrointestinal (GI) malignancies remains undefined. We aimed to elucidate the clinicopathologic and genomic landscape of KRAS G12C-mutated tumors compared to other G12 variants in a large non-colorectal GI cohort. Methods: We queried cBioPortal for pancreatic, esophagogastric, hepatobiliary, ampullary, and appendiceal adenocarcinomas. Following data quality control, the final cohort (n = 6,352) was stratified into KRAS wild-type (n = 3,293), G12C (n = 63), and other G12 variants (n = 2,996). Clinicopathologic features, tumor mutational burden (TMB), microsatellite instability status, and co-alteration in 96 key genes across 11 signaling pathways were compared. Statistical significance was assessed using Fisher’s exact or Chi-square tests for categorical variables and Kruskal-Wallis tests for continuous variables. The Benjamini-Hochberg method was applied to correct for multiple hypothesis testing. Results: KRAS G12C prevalence was 1.0% overall, with significant heterogeneity across cancer subtypes (p < 0.001). Appendiceal adenocarcinoma demonstrated the highest G12C prevalence at 5.71% (10/175), followed by ampullary (1.44%, 2/139), pancreatic (1.17%, 34/2906), hepatobiliary (0.88%, 12/1360), and esophagogastric cancers (0.28%, 5/1772). G12C patients were significantly older than wild-type patients (64.8±11.2 vs 62.5±12.9 years, mean±SD, p < 0.001) but younger than other G12 variant carriers (65.8±10.4 years). G12C tumors demonstrated intermediate genomic instability, with a TMB of 4.82±6.17 compared to 4.98±10.55 in wild-type tumors and 3.67±10.12 in other G12 variants (p < 0.001). Notably, G12C tumors were universally microsatellite stable (0% MSI-H vs 4.0% wild-type vs 0.9% other G12, p < 0.001). Genomic analysis revealed that AKT1 mutations were significantly enriched in the G12C cohort (6.3% vs 0.4%; q = 0.025) as compared to other G12 variants. A trend of increased mutation frequency in HRAS was observed specifically in pancreatic cancers in G12C tumors as compared to other variants (8.8% vs 0.7%; q = 0.083). In pancreatic adenocarcinoma, G12C tumors were enriched for chromatin modifiers, notably ARID1A (17.6% vs 7.7%, p = 0.045) and SETD2 / SETD26 (8.8% vs 1.1%, p = 0.006), though these did not reach FDR significance. Notably, the immunotherapy-resistance drivers STK11 and KEAP1 were absent (0%) in the whole G12C cohort. Conclusions: KRAS G12C represents a biologically distinct subgroup of exon 2 KRAS mutations compared to other KRAS G12 pathogenic variants. The absence of resistance markers and enrichment of actionable AKT1 and chromatin-modifier mutations suggest distinct therapeutic vulnerabilities in non-colorectal KRAS G12C-mutated GI cancers.

Abstract The proliferation of advanced endoscopic resection techniques has provided a minimally invasive alternative to esophagectomy and revolutionized outcomes for patients with early-stage esophageal adenocarcinoma (EAC). This paradigm shift and the resulting research data on clinical and histologic determinants of treatment outcome have highlighted the heterogeneity of outcomes within EAC staged as T1 by invasion depth. Multidisciplinary cancer care teams are now routinely facing difficult decisions regarding the management of high-risk T1 EAC to balance the risk of long-term lymph node (LNM) or distant metastasis against the risks of surgical resection. In this review, we summarize the current state of knowledge regarding the staging and risk stratification of T1 EAC, with particular attention to features that contribute to a higher risk of LNM and cancer mortality. We review recent clinical trial data on positioning the use of endoscopic resection (cap-assisted or submucosal dissection) versus surgical resection in high-risk T1 EAC patients and describe adjunctive techniques to further improve risk stratification and treatment. Finally, we explore emerging and future directions, such as artificial intelligence and advanced biomarker analysis to further aid decision-making and enhance patient outcomes.

Background: The purpose of this study was to describe, and report the outcomes of, a surgical technique that combines reverse shoulder arthroplasty (RSA) using an allograft-prosthetic composite (APC) with a lower trapezius transfer (LTT) to the infraspinatus of the allograft extended with the inferior capsule. Methods: Between 2019 and 2023, 2 surgeons performed a total of 27 RSAs using an APC in conjunction with an LTT. Once the RSA APC reconstruction had been performed, cuff-capsule allograft tissue was passed posterior to the glenosphere and secured to the harvested lower trapezius. One shoulder was resected for periprosthetic joint infection; the remaining 26 shoulders were followed for a minimum of 2 years (mean, 2.7 years; range, 2 to 5 years). Results: The rate of revision or reoperation for humeral complications was 15% and included secondary bone grafting (2 shoulders), resection for infection (1 shoulder), and internal fixation of a periprosthetic fracture (1 shoulder). Other complications requiring surgery included hematoma treated with evacuation (2 shoulders), dislocation (1 shoulder), and glenosphere disassociation (1 shoulder). Preoperatively, 11 shoulders presented with pseudoparalysis, and the mean active elevation of the remaining 16 shoulders was 43°, with only 1 shoulder demonstrating >90° of active elevation. At the most recent follow-up, 3 shoulders were pseudoparalytic, 11 had <90° of active elevation, 8 had >90° of active elevation, and 3 had active elevation to 90°. The overall mean active elevation of the 25 shoulders that could be assessed was 79°. Preoperatively, only 4 (15%) of the 27 shoulders demonstrated active external rotation past neutral; at the most recent follow-up, 80% of surviving shoulders had active external rotation past neutral. Conclusions: LTT at the time of RSA using an APC has the potential to restore active external rotation in shoulders with proximal humeral bone loss and posterosuperior cuff deficiency. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

ABSTRACT Richter transformation of Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) into classic Hodgkin lymphoma (CHL-RT) is rare and remains incompletely understood. Two histologic subtypes are recognized: type 1 (CLL/SLL with scattered Hodgkin/Reed-Sternberg (HRS) cells) and type 2 (HRS cells within a polymorphous inflammatory background). In this multi-institutional study of 77 patients with CHL-RT (27 type 1 and 50 type 2), we characterized immune evasion markers, PD-L1 / PD-L2 copy number alterations, tumor microenvironment, and performed targeted next-generation sequencing on 37 CLL/SLL samples. HRS cells in CHL-RT displayed immune-evasion phenotypes similar to de novo CHL, though PD-L1 expression was lower in type 1 cases. PD-L1/PD-L2 gain/polysomy were frequent (83.3%). CLL/SLL with CHL-RT harbored increased mutations in XPO1, FBXW7, BIRC3, TRAF3 , and HLA-A versus reference CLL/SLL. Similar mutational profiles, demographics, and survival outcomes support a biological continuum between type 1 and type 2 CHL-RT, with distinct genetic features in CLL/SLL predisposing to CHL transformation. STATEMENT OF SIGNIFICANCE Classic Hodgkin lymphoma-type Richter transformation arises from convergent Hodgkin-like immune evasion on a genetically primed CLL/SLL background. Through integrated genomic and tumor microenvironment analyses in a large multicenter cohort, we establish this as a biologically coherent entity and provide rationale for PD-L1/PD-L2-directed therapeutic strategies.

Abstract Members of the Transient Receptor Potential (TRP) family of ion channels have a nearly ubiquitous role in human physiology, tuning cell signaling to remarkably diverse physical and chemical stimuli. Although there is extensive structural data on TRP channels, a systematic and unbiased interrogation of structure-function relations in these proteins is required to fully elucidate their mechanisms of function. By focusing on a critical pore region of the TRPM8 channel, which is the main detector of cold and cooling agents in sensory neurons, we show how deep mutational scanning can be used in combination with the available structural data to understand how TRP channels respond to stimuli. We define a novel mechanism whereby the extracellular pore loop, which has only been resolved in structures representing desensitized states of the channel, plays an essential role in the response of TRPM8 to menthol or cold by coordinating the movement of the S6 helices that line and gate the pore, and the ion-selectivity filter that binds permeant cations. Moreover, our screen reveals sequence determinants along the S6 helices that explain how their architecture sustains gating and, together, provide strong support for a structural mechanism of TRPM8 pore opening in response to menthol and cold.

Background: The timing of coronary artery bypass grafting (CABG) in patients with non-ST-elevation myocardial infarction (NSTEMI) may critically impact clinical outcomes, yet the ideal surgical window remains unclear. We aimed to evaluate the association between time-to-CABG and in-hospital outcomes among NSTEMI admissions undergoing CABG. Methods: This retrospective cohort study utilized the US National Inpatient Sample database from 2017 to 2021 to evaluate the association between time-to-CABG and key in-hospital outcomes, including mortality, cardiac arrest, cardiogenic shock, ischemic stroke, acute kidney injury, and blood transfusion rates, while assessing length of stay (LOS) and hospital charges exclusively among survivors. Adult admissions with principal diagnosis of NSTEMI who underwent CABG without prior interhospital transfer were grouped by the calendar day of CABG from admission (0, 1, 2, 3, 4, 5, 6, and ≥7). Multivariate regression models were used to assess the outcomes across these eight groups. Results: Of 142,200 included admissions, same-day CABG (hospital day 0) was associated with the highest rates of in-hospital mortality, cardiac arrest, cardiogenic shock, and ischemic stroke. The adjusted odds of mortality, cardiac arrest, and cardiogenic shock were lower among admissions undergoing CABG between days 2 and 5. Likewise, the adjusted odds of ischemic stroke were lowest when CABG occurred on days 2 to 4. The odds of AKI increased when CABG was delayed beyond day 6, whereas blood transfusion rates showed no statistically significant association with time-to-CABG. Among survivors, LOS and hospital charges progressively increased with delayed CABGs. Conclusions: Among NSTEMI admissions undergoing CABG, CABG performed on hospital days 2 to 4 was associated with lower adjusted odds of several adverse in-hospital outcomes compared with same-day CABG. Further prospective studies are needed to validate these results and guide clinical decision-making.

ABSTRACT In 2018, the International Niemann‐Pick Disease Alliance (INPDA) and the International Niemann‐Pick Disease Registry (INPDR) developed and published comprehensive clinical management guidelines to support inclusive and standardized care pathways in Niemann‐Pick disease type C (NPC)—an ultra‐rare, autosomal recessive, neurovisceral lysosomal disorder. Since then, advances in diagnostics, care, and the approval of two novel disease‐modifying agents have underscored the need to revise these guidelines to ensure safe, consistent, and high‐quality care for those affected by NPC. In response, the INPDA and INPDR convened a multidisciplinary Guidelines Development Group (GDG) comprising individuals with NPC expertise from 14 countries across five continents, representing a broad range of specialties, as well as patients and families involved in NPC care. Informed by a comprehensive literature review and two meetings, the GDG systematically reviewed, revised, and updated the 2018 guideline statements, re‐evaluating the level of evidence, strength of recommendations, and expert agreement for each. The resulting 2025 consensus clinical management guidelines constitute a timely, up‐to‐date, and internationally applicable resource for the diagnosis, treatment, and holistic management of individuals with NPC. These guidelines serve as a critical resource for specialist centers, hospital‐based medical teams, staff involved in NPC patient care, family physicians and other primary caregivers, and, importantly, patients and their families.