Neurogastroenterology & Motility

Background & Aims: The association between upper gastrointestinal (GI) symptoms and delayed gastric emptying time (GET) is debated. This study utilized Body Surface Gastric Mapping (BSGM) and the 'Auckland Classification' BSGM phenotyping scheme to investigate whether symptom associations with GET vary across different mechanistic phenotypes. Methods: A pooled analysis was performed on two prospective datasets of 194 patients with chronic upper GI symptoms. Participants underwent simultaneous BSGM (Gastric Alimetry) and gastric emptying testing (breath test or scintigraphy). Validated time-of-test symptom profiling was recorded at 15-minute intervals using 0-10 Likert-type scales. Patients were classified: 'Spectral Abnormal' (abnormal electrophysiology), 'Sensorimotor' (symptoms correlate with gastric electrical amplitude), 'Continuous' (symptoms uncorrelated), and 'NA' (no phenotype). Results: In the analyzed cohort, 24% had delayed GET. Overall, delayed GET was associated with a higher total symptom burden (15.6 delayed vs. 8.8 normal, p=0.006; r=0.30, p<0.001), specifically postprandial fullness (p=0.004) and early satiation (p=0.015). However, associations varied significantly by phenotype. In the 'Sensorimotor' phenotype, nausea was associated with delayed GET (4.9 vs. 1.0, p=0.027; r=0.59, p=0.009), while total symptom burden was 23.3 vs. 8.4 (p=0.135). Conversely, patients with 'Continuous' or 'Spectral Abnormal' phenotypes, or who were unclassified, showed no symptom associations. Conclusions: Delayed GET is weakly associated with an increased burden of upper GI symptoms. However, gastroduodenal disorders are heterogeneous, such that phenotyping reveals this association to be exclusive to patients with a 'Sensorimotor' phenotype. These results could improve targeting of therapies that address gastric emptying.

Aims To develop the Bowel Irrigation Questionnaire (BIQ), a patient-reported experience measure (PREM) designed to assess the user experience of transanal irrigation (TAI). Methods Statements were generated through literature review and qualitative interviews with healthcare professionals (HCPs) and product users. Statements were rated on a 6-point content validity index scale through an international three-round online Delphi survey by 20 expert panel members. Consensus attainment was defined based on percentage agreement, statements which did not meet consensus were discussed at a final international online consensus meeting. The content validity of the PREM was evaluated through cognitive interviews and the Questionnaire on Questionnaires (QQ-10). Reliability was assessed using a test-retest design, where users completed the BIQ on two occasions one week apart. Results 215 statements were generated from 9 multi-disciplinary qualitative interviews and literature review. Statements were refined to reduce repetition and ensure clarity. 73 statements grouped into 11 domains were reviewed through the Delphi survey. Following the Delphi survey and clinical consensus meeting, the preliminary BIQ consisted of 15 items. Six cognitive interviews were conducted, resulting in a finalised BIQ of 16 items. 32 product users completed both the QQ-10 and test-retest study, the results of which demonstrated good content validity and temporal stability respectively. Conclusions The Bowel Irrigation Questionnaire is a novel PREM designed to assess the user experience of TAI in both clinical and research settings. The instrument demonstrates good validity, acceptability and temporal stability, supporting its use as a reliable measure of patient experience.

RationaleThere is no effective pharmacotherapy for obesity hypoventilation syndrome (OHS). Intranasal leptin augments the hypercapnic ventilatory response (HCVR), attenuates upper airway obstruction, and increases ventilation during sleep in diet-induced obese (DIO) mice. Respiratory effects of leptin can be attenuated by serotonergic antagonists. ObjectivesTo establish if serotonergic innervation of the hypoglossal motoneurons (XII MN) mediates effects of leptin on OHS. MethodsWe examined effects of intranasal leptin on the HCVR, sleep architecture, arousal latency, flow limited (obstructed) and non-flow limited breathing, genioglossus muscle (GG) activity and metabolic rate across sleep/wake states in the presence and absence of serotonergic neurons innervating XII MN in DIO Sert-flp mice expressing FlpO recombinase in the serotonergic neurons. These mice were transfected into the XII MN with retrograde adeno-associated virus carrying either FlpO-dependent caspase or control yellow fluorescent protein (YFP). Measurements and Main ResultsControl YFP virus was densely localized to the serotonergic neurons of the medullary raphe (MR), but not the dorsal raphe (DR), and these neurons were ablated by caspase. Leptin enhanced the HCVR, increased arousal latency in males, but not in females, and these effects were abolished by caspase. Neither leptin nor caspase affected sleep architecture or metabolic rate. Leptin increased GG activity awake and during NREM sleep, attenuated pharyngeal obstruction and increased minute ventilation in NREM and REM sleep. All effects of leptin were abolished by the FlpO-dependent caspase. ConclusionsLeptin treats OHS by stimulating MR serotonergic neurons, which project to XII MN and stimulate pharyngeal muscles during sleep.

Background and Aims: Endoscopic artificial intelligence is commonly validated on selected single images, whereas gastric cancer interpretation requires integrating whole examinations. We developed GutCore and evaluated whether whole-case endoscopic images could be used for patient-level assessment of gastric cancer depth, biomarkers, and prognosis. Methods: GutCore was pretrained on 5.6 million de-identified endoscopic images from more than ten hospitals. We compared it with five general, medical, and endoscopy-specific foundation models using open image-level datasets and an internal tertiary-center cohort of 11,035 de-identified endoscopic examinations (2019-2023): 8,049 with early or advanced gastric cancer and 2,986 with benign gastritis or intestinal metaplasia. All examination images were aggregated for patient-level assessment of cancer status, invasion depth, molecular biomarkers, and overall survival. Results: Aggregating all stored images from each examination enabled patient-level gastric cancer assessment without selecting representative frames. GutCore achieved AUCs of 0.995 for cancer detection, 0.960 for muscularis propria invasion, and 0.804 for SM2-or-deeper invasion. Prediction of tissue-defined biomarker status was strongest for Epstein-Barr virus status and MLH1 loss (AUC, 0.831 and 0.854), with lower HER2 performance (AUC, 0.673). In the held-out advanced gastric cancer test set, GutCore-derived risk groups showed marked survival separation (log-rank P < .0001; high-risk vs low-risk hazard ratio, 13.18; 95% CI, 6.06-28.66), with stratification persisting within pathological stage II and III disease. External frame-level benchmarks showed strong performance for anatomical landmark recognition, disease grading, and segmentation. Conclusions: GutCore supported whole-case patient-level gastric cancer assessment using routinely stored endoscopic images. Further validation in independent clinical cohorts is needed to establish generalizability and clinical utility.

Importance Sleep-disordered breathing (SDB) is common in childhood and is associated with attentional and behavioral impairments despite largely preserved sleep macrostructure and minimal abnormalities in conventional electroencephalographic measures. This discrepancy has contributed to the perception that sleep is relatively preserved in pediatric SDB and has limited understanding of the physiological mechanisms underlying morbidity. Objective To determine whether pediatric SDB is associated with disruption of the regional organization and homeostatic dynamics of slow-wave activity (SWA), a key physiological marker of sleep-dependent neural recovery and development. Design, Setting, and Participants Cross-sectional study of 62 children aged 4 to 12 years who underwent overnight polysomnography with high-density electroencephalography in a laboratory setting. Participants were recruited from clinical referrals and the community, spanning the full spectrum of SDB severity. Exposures SDB severity indexed by hypopnea index (HI), apnea-hypopnea index (AHI), and obstructive apnea index (OAI). Main Outcomes and Measures Regional electroencephalogram-derived SWA (0.5 to 4 Hz) topography and exponential decay parameters derived from frontal and posterior cortical regions. The frontal-to-posterior decay-rate ratio was evaluated as a summary measure of regional sleep homeostasis. Results In children with lower hypopnea index, SWA demonstrated the expected developmental pattern, with posterior predominance in younger children and a progressive shift toward a more balanced anterior-posterior distribution with age. Increasing HI was associated with attenuation or reversal of this spatial organization. Global SWA showed no meaningful association with SDB severity. In contrast, regional frontal and posterior decay parameters were strongly associated with HI (adjusted R2 = 0.53; p < 1e-6) but not OAI (adjusted R2 = 0.05; p = .95). The frontal-to-posterior decay-rate ratio showed the strongest association with HI {beta} = 4.15; 95% CI, 3.17-5.13; p < 1e-10; adjusted R2 = 0.55. Conclusions and Relevance Pediatric SDB was associated with regional disruption of slow-wave sleep homeostasis rather than global loss of deep sleep. These alterations affected both the spatial organization and temporal dynamics of SWA during a period of active cortical maturation and were not captured by conventional sleep metrics. Regional SWA dynamics may provide a developmentally sensitive marker of physiological disease burden in children with SDB.

Objectives: Explore the perspectives of primary caregivers towards pediatric tissue-based research participation. Design: Cross-sectional. Setting: Two academic pediatric gastroenterology sites in the United States, including one serving a largely rural referral population and one urban clinic population. Participants: Primary caregivers of children who underwent endoscopy between 2017-2018 at UVA or were seen in the clinic setting between 2024-2025 at Tulane and referred by their child's gastroenterologist to complete an electronic survey. Measures and Analysis: Primary caregiver attitudes, motivations, and concerns toward pediatric tissue-based research were explored using descriptive-focused coding in NVivo and a large language model (LLM) processing pipeline based on OpenAI's GPT-4 for thematic, emotional, and sentiment analyses. Results: Data were analyzed from 92 primary caregivers. Overall, respondents were amenable to having their children provide specimens for research. Primary motivations included a desire to help others or advance science, and perceived medical benefits for their child so long as specimen collection did not cause additional distress. Discomfort with participation was often linked to prior traumatic clinical experiences, concerns about additional biopsies causing unnecessary discomfort, or privacy issues. A desire to help others and potentially their own child was the strongest motivator for participation, while scheduling constraints and perceived risks to the child's health were the main barriers. Conclusions: At both sites, primary caregivers expressed strong willingness to participate in pediatric research. Primary concerns included perceived invasiveness of biospecimen collection and potential for additional discomfort. Limitations of the study included the unstructured nature of the data making the analysis and interpretation challenging. Strengths included two demographically diverse sites, intentional enrollment of primary caregivers of children both with and without invasive diagnostic testing, and use of LLM based analyses.

Background: The hydrodynamic model of hydrocephalus proposes that ventriculomegaly is driven by exaggerated intraventricular pulsations rather than impaired CSF circulation alone. Under this model, endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC) treats hydrocephalus by creating a pulsation absorber and by reducing a primary source of intraventricular pulsation. However, direct intraoperative human evidence supporting this two-step mechanism is lacking. This study aimed to test the hypothesis that ETV followed by CPC would produce measurable, stepwise decreases in mean intraventricular pressure (ICP) and pulsation amplitude in infants with hydrocephalus. Methods: This single-institution proof-of-concept study included infants with symptomatic hydrocephalus undergoing ETV/CPC as the first definitive treatment. A fiber-optic ICP sensor was attached to the operative ventriculoscope and passively recorded mean and pulsatile ICP (pulsation amplitude) throughout the procedure. Longitudinal brain parenchymal volume (BPV) and cerebrospinal fluid volume (CSFV) were obtained through segmentation of clinically acquired T2-weighted MRI and converted to age- and sex-matched z-scores. All patients were followed for a minimum of 6 months postoperatively. Results: Five infants (median corrected age at ETV/CPC 8 months) were included. No surgical complications occurred, and no ETV/CPC failures were observed during follow-up. Overall, mean ICP decreased by 56-97% after the combined procedure in four patients. In three patients (Patients 1, 3, and 5), both mean ICP and pulsation amplitude decreased stepwise following ETV and then CPC, consistent with the hypothesized therapeutic mechanism. Patient 4 demonstrated a large reduction in mean ICP after ETV with minimal additional effect from CPC and no significant change in pulsation amplitude. Patient 2 demonstrated neither a reduction in mean ICP nor a meaningful change in pulsation amplitude after either procedure; this patient also had a delayed and atypical clinical response. Intracranial segmentation demonstrated BPV z-score stabilization within normal range and CSFV plateau in all patients after surgery. Conclusions: This proof-of-concept study provides the first direct intraoperative human evidence supporting the hydrodynamic mechanism of ETV/CPC in a subset of infant with hydrocephalus. Our findings suggest that determination of intraoperative ICP parameters is feasible, safe and might ultimately prove helpful in improving patient selection for ETV/CPC, warranting further investigation in larger cohorts.

Background: Children with structural heart disease (SHD), particularly congenital heart disease (CHD), are increasingly recognised as being at risk of adverse neurological outcomes. Although advances in cardiac surgery and perioperative care have markedly improved survival, epilepsy has emerged as an important long-term complication. Reported prevalence estimates vary considerably across studies, and the overall burden remains uncertain. This systematic review and meta-analysis aimed to estimate the pooled prevalence of epilepsy among children with SHD and explore differences according to geographic region, lesion characteristics, and surgical exposure. Methods: This systematic review and meta-analysis was conducted in accordance with PRISMA 2020 and MOOSE guidelines and registered in PROSPERO (CRD420261378572). PubMed/MEDLINE, Scopus, and ProQuest were searched for observational studies published between January 2000 and December 2025. Eligible studies included children aged 0-18 years with SHD or CHD reporting epilepsy prevalence or incidence. Two reviewers independently screened studies, extracted data, and assessed methodological quality using the Joanna Briggs Institute Critical Appraisal Checklist for Prevalence Studies. A random-effects meta-analysis was performed to estimate pooled prevalence with 95% confidence intervals (CI). Results: Eight cohort studies comprising 21,731 children were included. Studies were conducted across North America, Europe, and Asia and predominantly involved surgically managed CHD populations. The pooled prevalence of epilepsy was 3.0% (95% CI 1.3%-4.8%), substantially higher than estimates reported in the general paediatric population. Heterogeneity was considerable (I{superscript 2} = 98.0%; p < 0.001). The 95% prediction interval ranged from 0% to 8.1%, indicating substantial variability across populations. Narrative subgroup synthesis suggested higher epilepsy prevalence among children with cyanotic and complex lesions and among surgically managed cohorts, particularly those exposed to cardiopulmonary bypass and perioperative neurological complications. Most studies were rated as having low risk of bias, and sensitivity analyses demonstrated stable findings. Conclusions: Children with SHD have a substantially increased burden of epilepsy compared with the general paediatric population. Complex lesions, perioperative neurological injury, and cardiac surgical exposure may contribute to epileptogenesis. Long-term neurological surveillance and multidisciplinary neurodevelopmental follow-up should be integrated into routine care for children with SHD.

Body surface gastric mapping (BSGM) enables non-invasive measurement of gastric electrophysiology, but the signals are approximately 100 times weaker than cardiac potentials and overlap spectrally with motion artifacts, necessitating labor-intensive manual review that limits clinical scalability. We present an uncertainty-aware deep learning framework combining a signal reconstruction network with a parallel uncertainty estimation network to automate artifact correction in high-resolution BSGM. Models were trained on 2,398 multihour, 64-channel recordings from 27 international clinical sites using weak supervision, a physiology-aware loss function, and uncertainty-gated quality control. In an independent cohort of 127 patients, the system achieved relative reductions of 39% in signal reconstruction error, 9% in total data removed, and 23% in amplitude--movement correlation compared with the industry-standard Wiener filter. Improved signal fidelity altered automated clinical phenotyping in 7% of patients by recovering previously obscured gastric rhythms. Uncertainty-aware deep learning enables reliable automated artifact correction in body-surface gastric mapping, improving signal fidelity and enabling scalable clinical interpretation. The system is FDA-cleared (510(k) K252504) and deployed in clinical practice, demonstrating that data-driven artifact correction can meet regulatory requirements for medical devices and reduce dependence on specialist manual review.

**Background:** Acute pancreatitis (AP) is a common gastrointestinal emergency with a subset of patients progressing to severe acute pancreatitis (SAP), which carries substantial morbidity and mortality. Current clinical severity scores such as BISAP, APACHE II, Ranson, and the Modified CT Severity Index require upon 48 hours of observation before reliable assessment is possible, limiting early triage. Machine learning (ML) approaches using routine admission laboratory values may enable earlier, more accurate prediction. **Methods:** We evaluated 11 models spanning three architectural families classical ML (Logistic Regression, Random Forest, Gradient Boosting), feedforward deep learning (MLP, Residual MLP, Attention MLP), and recurrent deep learning (LSTM, Stacked LSTM, Bidirectional LSTM, LSTM+Attention, CNN-LSTM) on a Chinese AP cohort of 722 patients (585 severe, 137 mild) labelled according to the 2012 Revised Atlanta Classification. Performance was assessed via 5-fold stratified cross-validation using AUC-ROC, F1 score, sensitivity, specificity, and PPV, with decision thresholds optimised for maximal F1. **Results:** Random Forest achieved the highest AUC of 0.877 (F1=0.917, sensitivity=96.8%, PPV=87.1%), followed closely by Gradient Boosting (AUC=0.874, F1=0.918). Classical ML models consistently outperformed deep learning counterparts. CNN-LSTM was the best recurrent model (AUC=0.777) but remained inferior to all classical approaches. LSTM-family models produced AUC values of 0.684-0.777, reflecting the cross-sectional tabular nature of the data. **Conclusions:** Random Forest provides robust, high-sensitivity early prediction of SAP severity using routine admission data. External prospective validation is required before clinical deployment. **Keywords:** acute pancreatitis; severity prediction; machine learning; random forest; deep learning; LSTM; Revised Atlanta Classification; early triage

Early acquired brain injury is a major risk factor for infantile epileptic spasms syndrome (IESS), which may impair cognitive development, especially if diagnosis and treatment are delayed. However, individual-level prediction of which infants will develop IESS is currently not possible. We assessed whether high-frequency oscillations (HFOs) in scalp EEG or recurrent interictal epileptiform discharges (IED) during the first months of life could predict forthcoming IESS. Our population-based cohort included 36 infants with cortical injury due to infarction, haemorrhage, infection or trauma involving a large cortical area ([&ge;] anterior/posterior cerebral artery territory or [&ge;] half of the middle cerebral artery territory), or hypoxic-ischaemic encephalopathy with cortical and deep grey matter involvement. The infants underwent repeated EEGs during the first year of life until 12 months of age or until IESS diagnosis. HFOs during sleep were scored both visually and automatically, whereas IEDs were assessed visually only. We tested whether HFO rate increased during the first year of life using a mixed-effects model with within- and between-subject random effects. Using only EEGs recorded prior to IESS diagnosis, we evaluated whether HFO rate or recurrent IEDs could predict IESS development by training a ridge-regularized logistic regression model with exhaustive leave-2-subjects-out cross-validation. Eleven infants (31%) developed IESS. HFO rate increased with age in both groups but more steeply in the IESS group [within person slope {beta} = 2.43 (IESS) vs. 0.06 (no-IESS) units/month, P < 0.001]. The logistic regression model showed that both HFO rate [AUC 0.801 (95% CI 0.668, 0.936)] and recurrent IEDs [AUC 0.826 (95% CI 0.720, 0.932)] were able to predict forthcoming IESS. However, in a multivariable model, only recurrent IEDs remained independently associated with IESS, and HFO rate did not add predictive value. The marked increase in HFO rate toward IESS diagnosis supports their role as a biomarker of epileptogenesis. During the first months of life, HFOs and recurrent IEDs performed equally well in predicting subsequent IESS. However, IEDs are easier to apply to clinical practice.

Background: Pediatric chronic pancreatitis (CP) carries an elevated lifetime risk of pancreatic ductal adenocarcinoma (PDAC), yet the cellular and molecular mechanisms driving disease progression and early neoplastic transformation remain undefined. Methods: We performed single-nucleus RNA sequencing (snRNA-seq) on pancreatic tissue from 15 pediatric CP individuals and 6 healthy controls (HC). Findings were integrated with peripheral blood flow cytometry immunophenotyping of 8 CP and 7 HC individuals and validated by histopathological assessment. Findings: We identified 15 distinct cell populations and profound cellular remodeling in CP, including a 46% reduction in acinar cells and emergence of inflammatory fibroblasts as the dominant stromal population. Acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) populations bearing early PDAC-associated transcriptional signatures were detected in most CP samples. Cell-cell interaction analysis revealed that 68% of CP-specific ligand-receptor interactions converged on ADM and PanIN populations via ECM-integrin and inflammatory pathways. Peripheral blood flow cytometry demonstrated concordant systemic immune activation, including elevated monocyte CCR2 and CD80, increased CD69 on T cells, and upregulated ROR{gamma}t in regulatory T cells. Interpretation: This atlas defines the cellular landscape and intercellular signaling networks underlying pediatric CP, identifying inflammatory fibroblasts and early neoplastic cell states as central features. These findings provide a molecular foundation for understanding cancer risk in pediatric CP and provide a resource to prioritize studies into potential therapeutic targets and biomarkers. Funding: This work was supported by the Network for Pancreatic Organ donors with Diabetes (nPOD) and The Leona M. & Harry B. Helmsley Charitable Trust.

Background: KRAS mutation status is an important biomarker in rectal cancer, with implications for prognosis and treatment response. MRI-based radiomics has emerged as a non-invasive approach for predicting tumor genotypes. However, the diagnostic performance of MRI radiomics for predicting KRAS mutation status remains unclear. This study aimed to evaluate the diagnostic accuracy of MRI radiomics for predicting KRAS mutations in rectal cancer. Methods: A systematic search of PubMed, Cochrane Library, Scopus, and Web of Science was performed through July 2025. Diagnostic test accuracy studies evaluating MRI-based radiomics or artificial intelligence models for predicting KRAS mutation status in adult patients with rectal cancer were included, using molecular testing as the reference standard. Risk of bias was assessed using the QUADAS-2 tool. Pooled sensitivity and specificity were estimated using a bivariate random-effects model. Results: Seven studies involving 1,224 patients were included. The pooled sensitivity was 0.736 (95% CI: 0.697-0.772) and the pooled specificity was 0.645 (95% CI: 0.586-0.701). The false positive rate was 0.355 (95% CI: 0.299-0.414). The area under the hierarchical summary receiver operating characteristic curve was 0.754, with a normalized partial AUC of 0.666. Between-study heterogeneity ranged from low to moderate depending on the estimation method (I2 = 8.4%-53.3%). Conclusion: MRI radiomics demonstrates moderate diagnostic accuracy for predicting KRAS mutation status in rectal cancer and may serve as a promising non-invasive biomarker for preoperative molecular stratification. Further large-scale studies with external validation are required to confirm its clinical utility.

Abstract Background: Sarcopenia is associated with anabolic resistance, a blunted muscle protein synthesis response to protein ingestion. Here, we hypothesized that anabolic resistance may be associated with a delayed postprandial decline in circulating plasma amino acids following protein ingestion. We therefore wanted to investigate whether an oral protein tolerance test (OPTT) combined with untargeted plasma metabolomics can detect age-related or sarcopenia-related differences in amino acid time courses consistent with altered postprandial amino acid handling, which could potentially reflect reduced anabolic sensitivity. Moreover, we investigated whether metabolites other than amino acids reacted to the OPTT. Methods: Twelve young healthy adults (controls: 22-28 years) and 12 older adults with clinically diagnosed probable or confirmed sarcopenia (70-91 years) ingested 20 g of whey protein after an overnight fast. We collected venous blood at baseline, 1 h, and 2 h post-ingestion and analyzed the samples by untargeted LC-HRMS plasma metabolomics. Linear mixed-effects models were fitted for 2,968 metabolic features with Benjamini-Hochberg FDR correction. For each category (branched-chain amino acid, essential amino acid [EAA], total amino acid) we summed the within-subject log2 fold changes (FC); fold changes (FC) of the constituent amino acids. This composite is reported as the summed log2FC. Results: 201 metabolites were structurally annotated including 58 amino acid-related metabolites and 97 lipids. Fourteen of 17 proteinogenic amino acids increased significantly after protein ingestion (FDR<0.05). In young controls, essential amino acids rose more steeply at 1 h than in sarcopenic individuals (+10.06 +/- 1.05 vs. +7.84 +/- 1.58 summed log2FC) and declined more between 1 and 2 h (-4.93 +/- 1.29 vs. -0.20 +/- 2.27 summed log2FC). Leucine exemplified this pattern best, rising 1.74 log2FC in controls and declining to 0.96 at 2 h, while remaining elevated at 1.61 log2FC in the sarcopenic group at 2 h (p=0.009). Beyond amino acids, whey protein lowered circulating free fatty acids in both groups (FA 18:2, FA 18:1, FA 16:0; all FDR<0.05). Medium- and long-chain acylcarnitines (Car 8:0, Car14:2) declined postprandially in controls but remained elevated in sarcopenic individuals (p<0.05), suggesting altered postprandial lipid metabolism. Conclusion: In this proof-of-concept study, an OPTT showed that plasma EAAs declined more slowly from their postprandial peak in older adults with sarcopenia than in young adults, consistent with altered postprandial amino acid handling that may reflect anabolic resistance. Whey protein ingestion additionally modulates lipid and acylcarnitine metabolism in an age-dependent manner, suggesting broader alterations in postprandial metabolic regulation in older adults with sarcopenia.

Niemann-Pick disease type C (NPC) is a rare autosomal recessive neurodegenerative lysosomal storage disease caused by pathogenic variants in NPC1 or NPC2. Sudden death can occur due to seizures, but cardiac involvement has not been well defined. We performed 12-lead electrocardiograms (ECG) in 14 adult NPC patients (8 male, 6 female). Cardiac structure and function were examined in Npc1-/- adult mouse hearts, alongside wild-type controls. Glycosphingolipid accumulation was quantified by high-performance liquid chromatography, fibrosis and collagen deposition were quantified using Massons Trichrome (M&T) and Picrosirius Red (PR) staining. Whole-heart morphology, including chamber size and wall thickness, was assessed. Ex vivo ECG recordings assessed conduction abnormalities and arrhythmias. RNA-seq transcriptomics characterised molecular pathways altered in Npc1-/- hearts. 8/14 patients showed ECG abnormalities including abnormal QRS transitions (N=8), increased QRS amplitude (N=4), fascicular block (N=2), and abnormal T wave inversion (N=1). 13 patients also had transthoracic echocardiograms identifying mildly impaired LV systolic function (N=2) and increased wall thickness/LV mass (N=4). In Npc1-/- mice, age-related glycosphingolipid accumulation was associated with pronounced ventricular fibrotic remodelling. There was a significant increase in stained connective tissue area and connective tissue to cardiac tissue ratio in both MT and PR staining. ECG from Langendorff-perfused Npc1-/- hearts showed QT prolongation and atrioventricular conduction abnormalities under isoprenaline stress. Transcriptomics revealed major changes in Npc1-/- hearts, consistent with histological fibrosis and linking NPC to inflammation-driven remodelling and arrhythmogenesis. These findings support routine cardiac screening in NPC patients and highlight the need for further studies to improve management and treatment.

Heart rate (HR) and its variability (HRV), mediated by the autonomic nervous system are key indicators of diving physiology and behavioral state, in vertebrates. However, these indicators remain understudied in cetaceans due to the technical challenges of recording electrocardiograms (ECGs) underwater. To overcome these challenges, we developed a waterproof device based on an all-in-one suction-cup that integrate an ECG-accelerometer logger with bipolar electrodes. Using this device, we obtained high-resolution ECG signals in bottlenose dolphins (Tursiops truncatus, n=8), belugas (Delphinapterus leucas, n=2), and orcas (Orcinus orca, n=1) during breathing and apnea. This approach allowed us to highlight species-specific features of the ECG waveform, consistent with a biphasic T wave in the three species of cetaceans and a bifid P wave unique to belugas, which were independent from the respiration state. Resting surface HRs were 70 {+/-} 4 bpm in dolphins, 51 {+/-} 1 bpm in belugas, and 50 {+/-} 2 bpm in the orca and exhibited pronounced oscillation related to the mechanism of respiratory sinus arrhythmia. As expected, short apneas ([~] 1 min) induced bradycardia in all three species (53 {+/-} 5, 33 {+/-} 3, and 37 {+/-} 2 bpm, respectively). In dolphins this bradycardia was coupled with a significant decrease of the coefficient of variability of RR intervals, one of the indices of HRV. Moreover, we were surprised to observe HR oscillations throughout apnea, suggesting a persistent fluctuation of autonomic modulation. Thus, to better understand autonomic modulation in cetaceans we employed food (fishes, squids, gelatin, etc.) as a strong rewarding stimulus. For that we compared HR and HRV during 2-min of food deprivation versus continuous feeding periods. In dolphins, food deprivation produced no significant change in HR or HRV from resting surface values, whereas continuous feeding decreased HR of about 20 % and increased HRV metrics (StDRR, CVRR, RMSSD). Belugas showed similar responses, with a HR decline of about 40 % and an increase HRV indices. These findings established baseline HR and HRV parameters during breathing or apnea for three cetacean species and demonstrate that autonomic responses to appetitive stimuli can be non-invasively quantified, validating a novel tool to investigate cetacean cardiovascular physiology and environmental perception.

Abstract (250 words) Background: Glutamine addiction is a hallmark of aggressive tumors, yet glutaminase (GLS1) inhibitor CB-839 showed disappointing anti-tumor efficacy in clinical trials. L-5-[11C]-glutamine ([11C]glutamine) PET enables non-invasive assessment of glutamine metabolism in vivo, providing a tool to test mechanistic hypotheses, and identify tumors likely to respond to GLS1 inhibition: focusing on compartmentation of GLS1-derived glutamate, CB-839 impact on flux, and reciprocal glutamine synthesis. Methods: Glutaminolytic TNBC (HCC1806) and poorly glutaminolytic ER+ (MCF-7) xenograft mice with or without CB-839, underwent dynamic [11C]glutamine PET. HPLC quantified fractional radioactivity of [11C]glutamine, soluble metabolites ([11C]glutamate, [11C]CO2), and macromolecule-incorporated metabolites from blood and tumor. A four-tissue compartment model characterized GLS1 activity (k_GLS) and flux, glutamine synthetase activity (k_GS), and subcellular glutamate distribution by comparing single vs. dual glutamate pool models. Averaged tumor curves and HPLC-derived tumor metabolites were fit. Monte Carlo simulations assessed parameter estimation performance. Results: The single glutamate pool model showed high correlations between k_GLS and other parameters, yielding inflated k_GLS estimates. The dual glutamate pool model reduced correlations, improved k_GLS recovery, and yielded subcellular glutamate distributions consistent with in vitro measurements. In TNBC, k_GLS was 3-fold higher than ER+ tumors (non-overlapping 95% CI) with glutamate concentrated in the mitochondrial compartment. CB-839 reduced k_GLS in TNBC and depleted mitochondrial glutamate (non-overlapping 95% CI), though glutaminolytic flux showed no distinguishable change. ER+ tumors showed higher k_GS compared to TNBC. Conclusion: [11C]glutamine PET kinetic analysis reveals distinct glutamine metabolic phenotypes in breast cancer subtypes. Preserved glutaminolytic flux and cytosolic glutamate in TNBC provide mechanistic hypotheses for clinical failure of GLS1 inhibitors, informing ongoing studies.

Atrial fibrillation (AF) is associated with an increased risk of neurological morbidity, yet its impact on cerebral perfusion and neuro-cardiorespiratory regulation remains incompletely understood. We used arterial spin labeling, blood oxygenation level-dependent functional MRI (BOLD-fMRI), and a breath-hold challenge to characterize alterations in 14 AF patients compared with 14 age-matched healthy controls. We also examined the changes after catheter ablation with pulmonary vein isolation (PVI) in a subset of patients. Compared with controls, AF patients exhibited widespread reductions in basal cerebral perfusion, including in brainstem regions involved in cardiorespiratory regulation, and a higher prevalence of periodic breathing during wakeful rest. During breath-hold challenge, the coupling between heart rate and BOLD signal changes ({Delta}BOLD) was smaller in AF, whereas {Delta}BOLD coupling with breath-by-breath O2-CO2 exchange ratio was greater at rest within pontine respiratory centers, indicating altered cardiac and respiratory contributions to cerebral hemodynamic regulation. Follow-up MRI scans 1-6 months after PVI demonstrated that restoration of sinus rhythm was associated with stronger heart rate-{Delta}BOLD coupling during breath-hold challenge, whereas basal cerebral perfusion showed no significant change. This dissociation suggests distinct temporal responses of neuro-cardiorespiratory coupling and cerebral perfusion after sinus rhythm restoration, while the timing of cerebral perfusion recovery remains unresolved.

Aims: Serrated lesions contribute substantially to colorectal cancer (CRC), while routine management of small distal hyperplastic polyps (HPs) assumes low risk. Surveillance guidelines nevertheless incorporate uncertainty at the HP/SSL interface and recommend shortened intervals for large serrated lesions. We tested whether fibroblast activation protein-alpha; (FAPalpha) expression by stromal fibroblasts within expert-reviewed HPs stratifies risk of subsequent neoplasia. Methods and results: In a single centre historical cohort, FAPalpha; immunohistochemistry (Abcam ab53066, 1:200) was performed on FFPE colon tissues from 64 patients (normal colon n=10; HP n=39; low grade TA n=6; high-grade TA n=4; adenocarcinoma n=5). FAPalpha positive stromal fibroblasts were quantified in 20 randomly selected fields at magnification 1000 by two blinded readers (ICC 0.93). Among 39 patients with expert reviewed index HPs and colonoscopic follow up, the endpoint was metachronous adenoma occurring in the same general colonic area as the index HP, with proximal defined as ascending colon and distal as descending colon. Follow-up colonoscopies were scheduled every 2 years for up to 10 years. ROC analysis identified an optimal threshold of [&ge;]9 FAPalpha positive fibroblasts (AUC 0.8658; sensitivity 81.25%, specificity 87.93%). FAPalpha high status (44% of HPs) was associated with shortened neoplasm free survival (log-rank p=0.0012): five-year neoplasm free survival 41% versus 91% for FAPalpha; no/low. In multivariable Cox modelling, FAPalpha high status remained independently associated with metachronous adenoma (HR 4.5, 95% CI 1.2-16.8, p=0.022). Conclusion: FAPalpha+ fibroblasts in expert-reviewed colorectal HPs identify a high-risk subgroup for metachronous adenoma, supporting stromal activation markers as a feasible pathology-anchored stratification tool.

Synthetic opioids like fentanyl are a leading cause of overdose mortality. Although the hallmark of fentanyl overdose is ventilatory depression, fentanyl also induces tonic activation of skeletal musculature, including the diaphragm, which may advance progression of overdose towards death. While tonicity may further restrict diaphragmatic contractility, phase-specific dysregulation may also reflect a larger state of discoordination in respiratory control. Using urethane-anesthetized mice exposed to fentanyl, we test the hypothesis that fentanyl-induced diaphragm tonicity results from a loss of coordinated motor activity. Fentanyl produced two distinct phases: an initial phase of maximal ventilatory depression with preserved phasic activity, and a later phase characterized by unstable ventilation that partially rebounds, tonic diaphragmatic activation with loss of inspiratory phase dominance in EMG activity, and diminished bilateral diaphragmatic coordination. Carotid body denervation eliminated tonic activity and expiratory-phase EMG elevation, but it did not prevent hemi-diaphragm discoordination or ventilatory instability. Rhythmic brainstem slice recordings showed that bilateral preBotzinger complex burst-amplitude coupling was disrupted by u-opioid receptor (MOR) agonism. Furthermore, disordered diaphragm activity was reversed by administration of the MOR antagonist, Naloxone. Our findings reframe fentanyl overdose as a temporally evolving syndrome that involves distinct mechanisms to disrupt respiratory motor coordination.