Citations

Abstract Interstitial cells of Cajal (ICC) regulate gastrointestinal motility by generating electrical slow waves that orchestrate downstream calcium (Ca 2 + ) waves and coordinate smooth muscle contractions. A reduced ICC number has been reported in diabetic gastroparesis patients and in mouse models of delayed gastric emptying (DGE). However, functional changes in ICC propagating across the gastric regions in intact stomach are not well understood. The aim of this study was to develop an imaging approach to visualize ICC Ca 2+ waves in mouse stomach and determine spatiotemporal changes in mice with DGE. Tamoxifen‐treated B6.GCaMP5‐KitCreERT2 female mice were used as non‐diabetic controls (Non‐Db), while mice treated with streptozocin to induce diabetes were categorized as having normal (Db‐NGE) or delayed (Db‐DGE) gastric emptying based on emptying of solids. The ICC Ca 2+ network was imaged from excised intact mouse stomachs and subsequently opened along the lesser curvature and pinned flat. ICC Ca 2+ waves typically propagated along the greater curvature from the fundus–corpus line toward the antrum. The propagation length of ICC Ca 2+ activity was significantly decreased in Db‐DGE compared to Non‐Db and Db‐NGE and correlated to longer GE times. There was also a decrease in frequency, and the velocity was significantly faster in stomachs from Db‐DGE compared to Non‐Db and Db‐NGE. All experimental groups exhibited similar proportions of aberrant Ca 2+ propagation patterns (e.g., retrograde waves), but ectopic initiation only occurred in Db‐DGE stomachs. Thus, DGE is possibly driven by dysfunction in Ca 2+ activity in the ICC network that propagates rapidly over short distances, resulting in uncoordinated, non‐phasic muscle activity. image Key points Dysfunction of the interstitial cells of Cajal (ICC) has been implicated in diabetic gastroparesis but the changes in spatiotemporal properties of ICC network activity are not known. We developed an ex vivo Ca 2+ imaging approach to visualize ICC network activity across the entire stomach and determined changes in ICC Ca 2+ activity in a diabetic mouse model of delayed gastric emptying (GE). Decreased frequency and increased velocity of ICC Ca 2+ activity was observed in stomachs of diabetic mice with delayed GE. Ectopic initiation was a key feature associated with delayed GE. The propagation length of ICC Ca 2+ activity was inversely correlated to GE times and significantly reduced in stomach preparations from diabetic mice with delayed GE.

TPS8124 Background: Immune checkpoint inhibitor (ICI)–based regimens are standard first-line therapy for metastatic non–small-cell lung cancer (NSCLC) without actionable driver mutations; however, most patients experience disease progression within 12 months. A subset develop oligoprogression, defined by progression at a limited number of metastatic sites with otherwise controlled disease. Oligoprogression represents a therapeutic window in which local ablative therapy could be used to prolong disease control. In the prior phase II CURB trial, SBRT was shown to significantly prolong progression-free survival (PFS) in patients with oligoprogressive NSCLC. Methods: CCTG-BR38 is an international, multicenter, open-label, randomized phase III trial conducted through the NCI National Clinical Trials Network. Adults with stage IV NSCLC receiving first-line ICI ± chemotherapy who develop ≤5 extracranial oligoprogressive lesions are randomized 1:1 to: (1) switch to second-line standard systemic therapy or (2) SBRT (30 Gy in 3 fractions) to all oligoprogressive sites followed by continuation of the same first-line systemic therapy. Randomization is stratified by type of first-line systemic therapy (ICI alone vs ICI + chemotherapy), number of oligoprogressive lesions (1–2 vs 3–5), and ECOG performance status (0-1 vs 2). Patients with treated, stable brain metastases are eligible. Primary Endpoints: Dual primary endpoints are PFS and overall survival (OS). Secondary endpoints include safety (CTCAE v5.0), patient-reported adverse events (PRO-CTCAE), quality of life (EORTC QLQ-C30/LC13), and cost-effectiveness (EQ-5D-5L; Canadian sites). Optional blood and tissue collection for exploratory biomarker analyses are planned. Statistical Considerations: A total of 320 patients (160 per arm) will be enrolled. The sample size is based on detecting a HR of 0.7 for OS (an improvement in median OS from 10 to 14.3 months) with 80% power using a 1-sided 2% level test (the overall 1-sided 2.5% type I error will be assigned 2% to OS and 0.5% to PFS). Interim analyses for futility and efficacy are planned. Current Status: The trial was centrally activated on April 3, 2025. Accrual is ongoing across Canadian and US NCTN sites. Clinical trial information: NCT06686771 .

e18602 Background: Chimeric antigen receptor T-cell (CAR-T) therapy has transformed the treatment of hematologic malignancies but is frequently complicated by cytokine release syndrome (CRS) and immune-mediated neurotoxicity (NS). As CAR-T programs expand, population-level projections of treatment-related toxicities are essential for program planning and risk mitigation, yet remain poorly characterized. Methods: We performed a cohort-based forecasting analysis using pooled incidence rates of CRS and NS derived from published meta-analyses of CAR-T clinical trials. Expected numbers of toxicity events were projected for hypothetical cohorts of 100, 500, and 1,000 CAR-T–treated patients. Uncertainty was quantified using binomial 95% confidence intervals. Disease-specific projections were generated by applying stratified pooled toxicity rates for hematologic malignancies and solid tumors. Results: For a projected cohort of 1,000 CAR-T–treated patients, forecasts estimated approximately 770 patients would experience CRS of any grade, 290 would develop grade ≥3 CRS, 400 would experience NS of any grade, and 280 would develop grade ≥3 NS. Toxicity counts increased proportionally with cohort size and demonstrated predictable uncertainty bounds. When stratified by disease type, hematologic malignancies exhibited substantially higher toxicity burdens than solid tumors across all endpoints. At a cohort size of 1,000 patients, hematologic malignancies were associated with markedly higher rates of both CRS and severe neurotoxicity, whereas solid tumors demonstrated consistently lower toxicity burdens. Conclusions: Using pooled clinical trial data, this forecasting model provides quantitative estimates of CAR-T–associated toxicity burdens at the population level. Severe CRS and neurotoxicity remain common and scale predictably with program size, particularly in hematologic malignancies. These findings offer a pragmatic framework for anticipating resource utilization, toxicity management needs, and safety planning as CAR-T therapy continues to expand.

e18536 Background: Nucleophosmin 1 (NPM1) mutation is traditionally associated with a favorable prognosis in acute myeloid leukemia (AML), leading to classification of these patients within the European LeukemiaNet (ELN) favorable risk group. However, emerging evidence indicates that co-occurring secondary-type mutations (STMs), including ASXL1 , RUNX1 , EZH2 , and SRSF2 , may substantially modify this prognosis. While meta-analyses have quantified the relative risk associated with STMs using hazard ratios, the corresponding absolute survival impact remains unclear, limiting clinical interpretability and decision-making. Methods: We performed meta-analysis–based projection modeling using pooled overall survival hazard ratios reported in a recent systematic review and meta-analysis of 4,022 NPM1-mutated AML patients. For the ELN-favorable subgroup, the pooled hazard ratio for overall survival associated with STMs (HR 1.95; 95% CI 1.39–2.73) was combined with externally derived baseline 5-year survival estimates under a proportional hazards framework. Absolute survival probabilities were calculated using established survival–hazard transformations, and results were translated into projected outcomes for a hypothetical cohort of 1,000 future ELN-favorable NPM1-mutated AML patients. Uncertainty was quantified using the meta-analytic confidence interval. Results: Assuming a baseline 5-year overall survival of 70% for ELN-favorable NPM1-mutated AML patients without STMs, the presence of STMs was projected to reduce 5-year survival to approximately 50%. Based on the confidence interval of the pooled hazard ratio, projected survival with STMs ranged from 38% to 61%. In a simulated cohort of 1,000 patients, this corresponds to approximately 300 deaths at 5 years in the absence of STMs versus 501 deaths in the presence of STMs, yielding an estimated 200 excess deaths per 1,000 patients (plausible range: 90–320 excess deaths). These findings were robust across visualizations including absolute survival projections, stacked outcome distributions, and excess mortality estimates. Conclusions: Meta-analysis–based projection modeling demonstrates that secondary-type mutations may negate much of the favorable prognosis traditionally attributed to ELN-favorable NPM1-mutated AML, translating into a large absolute survival decrement in future patient cohorts. Converting relative risk estimates into absolute survival and event projections provides clinically actionable insight and supports the incorporation of secondary-type mutation status into risk stratification, trial design, and therapeutic decision-making.

Introduction: Inflammatory bowel disease is characterized by remitting and relapsing bouts of intestinal inflammation accompanied by sensory and motor dysfunction that persists beyond the active periods of inflammation. Evidence suggests that neural pathways of the Gut-Brain Axis, particularly the sensory and sympathetic nervous system, are involved in pathophysiology, but until recently technical restrictions have limited our understanding of the underlying neural circuit mechanisms. In this study, we examined how sensory-sympathetic circuits are modified by colitis and how these alterations contribute to dysfunction during both active inflammation and post-inflammatory recovery. Methods: E2a-GCaMP mice were treated with vehicle or 3% dextran sodium sulfate (DSS) for 5 days to induce experimental colitis and switched to normal drinking water. Mice were assessed at two time points: Day 7 (two days after ending DSS treatment), representing active inflammation, and Day 21 to represent recovery. Inflammation and mucosal damage were evaluated using disease activity index scores and hematoxylin and eosin (H&E) staining. Colon motility was assessed in vivo via colonic bead expulsion and ex vivo using whole-colon preparations. We performed Ca 2+ imaging of sympathetic motor neurons in prevertebral ganglia (PVG) and sensory neurons in dorsal root ganglia (DRG) neurons in ex vivo preparations that preserve extrinsic neural circuitry with the colon (intestinofugal-sympathetic and spinal cord-sympathetic pathways). Results: Histological analysis confirmed hallmark features of colitis, including colon shortening, immune infiltration, and mucosal damage at 7 days post-DSS (p< 0.05, n=3–4), which resolved after recovery. During active inflammation, in vivo colon transit time was significantly faster, and this persisted after recovery (p< 0.05, n=7-9). Ex vivo motility assays in isolated colons also revealed DSS-induced dysmotility during active inflammation, but the irregular colon motor complexes became normal after recovery (p< 0.05, n=7-9), suggesting that extrinsic neural pathways contribute to prolonged dysmotility. In preparations without the spinal cord, PVG neurons exhibited increased activity and increased responses to distension during active inflammation but returned to baseline after recovery (p< 0.05, n=3-4), suggesting alternative sensory-PVG pathways contribute to persistent dysmotility. In preparations with spinal circuits intact, thoracolumbar (TL), but not lumbosacral (LS), DRG sensory neurons were hypersensitive to colonic distension during inflammation (p< 0.05, n=8-9). Furthermore, TL spinal stimulation evoked more responses in PVG neurons during active inflammation, but this was associated with decreased inhibition of ENS motor circuits (p< 0.05, n=6-7) and increased Ca 2+ signaling in the epithelium (p< 0.05, n=5), suggesting shifts in TL spinal-sympathetic motor output. Preliminary studies show an increase in spontaneous activity of TL DRG neurons in recovery that does not occur at LS levels (p< 0.05, n=3-6), which suggests that thoracolumbar spinal pathways remain hyperexcitable after recovery.Conclusions: Our findings indicate that TL spinal pathways associated with sympathetic motor outflow contribute to pain and dysmotility during active inflammation and may contribute to the post-inflammatory recovery processes that seem to go awry in IBD patients with relapsing inflammation. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Background: As part of the bidirectional gut-brain communication system that influences gastrointestinal function, vagal pathways coordinate with the activity of interstitial cells of Cajal (ICC) to regulate gastric motility. Impairments in ICC slow wave activity and altered vagal tone have been implicated in diabetic gastroparesis and obesity, but technical limitations have restricted our ability to measure integrated and bidirectional activity in vagal-ICC pathways. Furthermore, the influence of physiological and meal-induced stimuli like gastric distension on these pathways is not well understood. We aimed to develop a calcium imaging approach in ex vivo nodose ganglion-vagus nerve-stomach preparations to investigate vagal-ICC pathways and test the effects of gastric distension on vagal activation, ICC network activity, and their functional interactions. Methods: Calcium imaging was performed in ex vivo preparations, in which the stomach and vagus nerves (with or without the ganglion) remain intact. EIIa-GCaMP6 (n=3) and cKit-GCaMP6 (n=3) mice were used to image Ca 2 + signals from both vagal neurons and ICC or ICC alone, respectively. Two-minute recordings were captured in the following stomach conditions: (1) Undistended; (2) Undistended + vagal nerve stimulation (VNS, 20 Hz, 1 s); (3) Distended (0.25 ml volume distension); (4) Distended + VNS. Ca 2 + signals in ICC and neurons, along with tissue displacement, were analyzed using Image J. Data from both GCaMP models were pooled for ICC. Results: Acute gastric distension significantly activated vagal sensory neurons in nodose ganglion compared to baseline (p=0.0193), and VNS evoked Ca 2 + responses in ICC and neurons, confirming intact nerve pathways. Both VNS and gastric distension altered the direction of ICC propagation, significantly increasing retrograde waves (p=0.0025 and p=0.0032, respectively), and VNS had no effect on retrograde waves in distended stomachs. VNS and distension also reduced length of propagation of anterograde ICC waves (p=0.019 and p=0.0004, respectively), and again, VNS effects were not observed during distension. VNS increased the velocity of ICC wave propagation, but only in undistended stomach (p=0.0283). Finally, VNS increased ICC pacemaker frequency regardless of the distension state (p=0.0123). Conclusion: Both acute gastric distension and VNS altered ICC network activity, with similar effects on network parameters. However, most of the VNS effects on ICC were blocked during distension. VNS increased the frequency of ICC network waves in both undistended and distended stomachs, suggesting that VNS can influence ICC pacemakers regardless of distension state. These findings have important implications for designing therapeutic strategies for gastroparesis. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Morel-Lavallee lesions (MLLs) are traumatic closed degloving injuries with operative intervention (OI), especially excisional debridement, remaining the mainstay of treatment. However, high-quality evidence describing operative techniques and outcomes remains limited. This study aimed to characterize current OI practices and associated outcomes, especially among patients undergoing excisional debridement, hypothesizing an increased risk of wound complications with this approach for MLLs. Methods This prospective (2021-2024), multicenter, observational study was conducted across 15 trauma centers and included patients diagnosed with MLL who underwent OI. The association between operative technique (eg, excisional debridement) and the primary outcome of wound complications was evaluated. Wound complications were defined as cellulitis, deep wound infection, skin necrosis, necrotizing soft tissue infection (NSTI), and/or organized hematoma. Results Of 88 MLL patients undergoing OI, 36 (40.9%) had excisional debridement, with 4 (11.1%) limited excision to skin, 20 (55.6%) extended to subcutaneous tissue, and 12 (33.3%) down to muscle. Excisional debridement had higher rates of skin necrosis (22.2% vs. 1.9%, P = .002). Although overall rates of wound complications were statistically similar between cohorts (33.3% vs. 17.3%, P = .098), univariate analysis demonstrated excisional debridement had increased risk of wound complications (OR 2.52, CI 1.07-5.97, P = .035). Conclusion This prospective multicenter study over three years demonstrated that a fifth of MLLs undergoing excisional debridement developed postoperative skin necrosis. Excisional debridement also had a more than two-fold increased risk of wound complications compared to other OIs. These findings underscore the importance of investigating alternative operative techniques, such as incision and drainage or minimally invasive debridement methods.

Background Ketamine has demonstrated efficacy in treatment-resistant depression, primarily in psychiatric or outpatient populations. Its use in ICU patients remains underexplored, with limited data beyond case reports and small series. This study evaluated the association between subanesthetic ketamine infusions and improvement in depressive symptoms and hemodynamic changes in ICU patients. Methods We conducted a retrospective study of adults admitted to the ICU who received IV ketamine (0.3-0.75 mg/kg over 40 min on three consecutive days) for depressive symptoms. Changes in depressive symptoms were assessed using routine clinical documentation by physicians, nurses, and occupational and physical therapists. Hemodynamic parameters (blood pressure and heart rate) were recorded before and up to 120 min after infusion. The primary outcome was to evaluate depressive symptoms while the secondary outcome was to assess hemodynamic changes post transfusion. Results Thirty-four patients met criteria, including 18 solid organ transplant recipients. Median age was 59 years; 61.8% were male. Ketamine was associated with improvement in apparent sadness (90.0% vs 52.2%, P < .05) and reported sadness (95.0% vs 59.1%, P < .05). In transplant recipients, improvement in apparent sadness remained significant (80.0% vs 41.7%, P < .05). Hemodynamic parameters remained stable; heart rate increased transiently at 15-30 min post-infusion, returning to baseline by 60-90 min. Adverse effects observed were anxiety (12.5%), restlessness and/or agitation (10.4%), and dissociation (8.16%). Conclusion Subanesthetic ketamine improved specific depressive symptoms in critically ill ICU patients without significant hemodynamic instability. These findings support its potential as a rapid-acting antidepressant in the ICU, warranting further prospective trials.