Citations

ABSTRACT Introduction Chronic gastroduodenal disorders remain challenging to manage, and new diagnostic approaches are needed to better delineate underlying causes and guide therapeutic decisions. Body Surface Gastric Mapping (BSGM) technologies combine high‐resolution gastric myoelectrical activity measurements with symptom and psychological profiling to provide mechanistic insights into gastric motor and sensory dysfunction. An International Working Group convened to derive the first consensus classification of BSGM phenotypes (the “Auckland Classification”). Methods A Technical Group conducted a systematic literature and clinical database review to identify objective test biomarkers and candidate disease mechanisms. Evidence was synthesized across 50 studies (primarily in gastroparesis, chronic nausea and vomiting, and functional dyspepsia), and BSGM phenotypes were mapped to existing treatment guidelines. Subsequently, iterative review and development of consensus was performed by a Consensus Group composed of international clinical experts familiar with BSGM. Eleven statements underlying the classification were then derived and circulated as a final survey to establish agreement. Results Six BSGM phenotypes were endorsed: three defined by myoelectrical abnormalities (Dysrhythmic, High Frequency, and Low Meal Response) and three by characteristic symptom associations (Sensorimotor, Continuous, and Delayed Onset Symptoms). Published studies plausibly linked these phenotypes to mechanisms including interstitial cell of Cajal depletion, vagal impairment, hypomotility, visceral hypersensitivity, gut‐brain dysregulation, and small bowel dysfunction. Phenotypes were also mapped to existing mechanism‐based treatment guidelines. Ten out of the eleven statements had > 80% agreement. Conclusions The Auckland Classification, derived by international consensus, presents a structured framework for BSGM‐defined patient phenotypes. Evidence and mechanism‐based treatment options are suggested for each phenotype to provide a foundation for research, further validation, and a pathway for integrating BSGM into clinical care.

ABSTRACT Background Patients with gastroparesis (Gp) can have a variety of symptoms. Apart from use of prokinetics, symptomatic therapies for the predominant symptom (PrS) are used. Aims (1) To classify Gp patients based on their PrS; (2) To determine differences in Gp symptoms, gastric emptying (GE), quality of life (QOL), treatments, and symptom improvement among Gp patients with different PrS. Methods Gp patients were enrolled in a multicenter registry and followed for 96‐weeks. Patients recorded their PrS and completed questionnaires assessing symptoms and QOL at enrollment and at follow up visits. Results Of 1013 Gp patients (361 diabetic, 607 idiopathic, 45 post‐fundoplication), the PrS were nausea (31%), vomiting (20%), abdominal pain (20%), bloating (9%), fullness (4%), GERD (4%), constipation (3%). Abdominal pain was more often a PrS in idiopathics, whereas vomiting was more often a PrS in diabetics. QOL scores were lower in the abdominal pain PrS group. PrS was associated with greater use of directed symptomatic treatment (antiemetic agents and gastric electrical stimulation for nausea and vomiting, prokinetic agents for vomiting and fullness, and constipation medications for constipation). Of 555 patients followed over 48 weeks, GCSI improved by ≥ 1 in 26% overall, more often in patients with initial PrS of nausea (32%) and bloating (35%) and less often for initial PrS of fullness (13%) or abdominal pain (15%). Conclusions In Gp patients, the most common PrS were nausea, vomiting, and abdominal pain. PrS is associated with QOL, treatments utilized, and patient outcomes. Thus, the PrS of a patient with Gp provides useful information about their present condition and future outcome.

ABSTRACT Background Patients with gastric dysmotility exhibit abnormal transit and reduced contractility, for which quantification is limited with current methodologies. The Atmo Capsule is a wireless motility capsule that measures regional gastrointestinal transit. We tested its technical capabilities to evaluate gastric contractility by detecting changes in capsule acceleration during transit. Methods Data from 91 healthy controls and 182 patients with suspected dysmotility who ingested the Atmo Capsule following a standardized protocol were included. Gastric emptying times (GET) ≥ 5 h were considered delayed. Contraction frequencies (cycles per minute [cpm]) and amplitudes (as arbitrary units [au]) were identified following Fast Fourier Transformation of accelerometer data using 5‐min windows and were assessed in 30‐min windows post‐ingestion (early gastric phase) and before gastric emptying (late gastric phase). Data were compared via ANOVA, using Bonferroni corrections, between healthy controls, patients with normal gastric emptying, and patients with delayed gastric emptying. Key Results Gastric emptying was delayed in 53/182 (29%) patients. Three cpm contraction frequencies were identified across both gastric phases in controls and patients. Contraction amplitudes did not differ between groups in the early gastric phase. In the late phase, mean amplitudes were lower in patients with delayed gastric emptying (6.4 au) compared with subjects with normal gastric emptying (controls, 9.7 au, p < 0.0001; patients, 8.6 au, p < 0.0001). Conclusions & Inference The Atmo Capsule enables precise quantification of gastric contraction profiles, permitting differentiation of normal from pathological motor patterns. Findings of this technical assessment support its potential for evaluating gastric physiology and detecting pathophysiological patterns of gastric dysmotility.

ABSTRACT Background Chronic gastroduodenal symptoms arise from heterogeneous gastric motor dysfunctions. This study applied multimodal physiological testing using gastric emptying scintigraphy (GES) with intragastric meal distribution (IMD) and Gastric Alimetry body surface gastric mapping (BSGM) to define motility and symptom associations. Methods Patients with chronic gastroduodenal symptoms underwent simultaneous supine GES and BSGM with a 30 m baseline, 99mTC‐labeled egg meal, and 4 h postprandial recording. IMD (ratio of counts in the proximal half of the stomach to the total gastric counts) was calculated immediately after the meal (IMD0), with < 0.568 defining abnormal IMD. BSGM phenotyping followed a consensus approach, based on normative spectral reference intervals. Results Among 67 patients (84% female, median age 40 years, median BMI 24 kg/m 2 ), median IMD0 was 0.76 (IQR: 0.69–0.86) with 5 (7.5%) meeting abnormal IMD criteria. Delayed gastric emptying ( n = 18) was associated with higher IMD0 (median 0.9 vs. 0.7, p = 0.004). On BSGM, 15 patients had abnormal spectrograms (5 [7.5%] high frequency and 10 [14.9%] low rhythm stability and/or amplitude); and in these patients, higher IMD0 (proximal retention) strongly correlated to delayed BSGM meal responses ( R = −0.71, p = 0.003). Lower IMD, indicating antral distribution, correlated with higher gastric frequencies ( R = −0.27, p = 0.03). BSGM abnormalities paired with abnormal IMD were associated with worse dyspeptic symptoms. Conclusion Proximal retention of food as assessed by IMD correlated with delayed emptying, and in the presence of neuromuscular spectral abnormalities (abnormal frequencies or rhythms), delayed motility responses on BSGM. Patients with multiple motor abnormalities experience worse dyspeptic symptoms.

ABSTRACT Background Chronic neurogastroduodenal disorders are challenging to manage, with therapy often initiated on a trial and error basis. Prokinetics play a significant role in management, but responses are variable and have been associated with adverse events, impacting widespread use. We investigated whether body surface gastric mapping (BSGM) biomarkers (using Gastric Alimetry) could inform patient selection for prokinetic therapy. Methods Patients with chronic gastroduodenal symptoms taking oral prokinetic agents, regardless of gastric emptying status, were prospectively recruited and underwent BSGM (30 m baseline, 482 kcal standardized meal, 4 h postprandial recording) while off‐prokinetic agents. Patients were followed up with daily symptom diaries. A subset was compared to matched patients not taking prokinetic agents. Prokinetic responders were defined based on symptom improvement greater than a minimum clinically important difference methodology. Key Results Forty‐two patients (88% female; median age 36; median BMI 26) taking prokinetics were analyzed. Prokinetic prescribing, compared to matched patients, was independent of BSGM metrics ( p > 0.15). In patients on existing prokinetics (withheld for BSGM), lower amplitudes predicted reduced symptom burden, whereas low rhythm stability predicted a worse symptom burden ( p < 0.05). In prokinetic‐naive patients (i.e., started on a prokinetic during the study), a lower postprandial amplitude predicted responders (mean 37.5 ± 10.6 uV in responders [ n = 5] vs. mean 54.8 ± 6.6 uV among nonresponders [ n = 3], p = 0.047). Conclusions Gastric Alimetry biomarkers may help in the prediction of prokinetic response in patients with chronic gastroduodenal symptoms. Lower postprandial amplitudes, indicating a reduced meal response, appear to predict benefit, while impaired rhythm stability predicted poorer therapeutic response.

INTRODUCTION: Chronic neurogastroduodenal disorders are heterogeneous and thought to lie on a spectrum of disease encompassing both sensory and neuromuscular pathologies. Abnormalities of interstitial cells of Cajal (ICC), a subset of which generate pacemaker signals and subsequently motility, have been implicated in their pathophysiology. We systematically reviewed the literature to pool ICC deficits observed in chronic neurogastroduodenal disorders. METHODS: Studies quantifying gastric ICC from the corpus or antrum, in adult patients with gastroparesis, functional dyspepsia (FD), or chronic nausea and vomiting syndromes (CNVS) were analyzed (PROSPERO: CRD42024613226). MEDLINE, Embase and CENTRAL databases were searched systematically. Random effects meta-analyses were used to compare ICC counts by disorder group with subgroup analysis by quantification methodology. RESULTS: Overall, 2,158 studies were screened and 22 included. Comparative studies (n = 12) showed patients with chronic neurogastroduodenal disorders (n = 167 with gastroparesis, n = 19 with FD ± CNVS) had lower ICC counts than nondiabetic controls (n = 130); standardized mean difference −1.58, 95% confidence interval −2.09 to −1.07, P < 0.0001, with more severe deficits in gastroparesis compared to FD ± CNVS (standardized mean difference [SMD] −0.44, P = 0.048). A spectrum of ICC deficits was evident in a subgroup of studies using gold-standard methods with c-KIT antibody and 4',6-diamidino-2-phenylindole-stained nuclei confirmation (7 studies, 246 patients: mean ICC counts 2.29 in gastroparesis vs 3.49 in FD ± CNVS, and 5.27 in controls; P < 0.001 all comparisons). Most studies were at high risk of bias (n = 21). DISCUSSION: Marked depletion of ICC is a consistent finding in neurogastroduodenal disorders. A spectrum of disease is revealed, with greater depletion associated with delayed emptying. Techniques for clinically defining ICC-driven gastric neuromuscular dysfunction should be prioritized.

AbstractBackgroundGastroparesis (GP) is characterized by delayed gastric emptying in the absence of mechanical obstruction.ObjectiveGenetic predisposition may play a role; however, investigation at the genome‐wide level has not been performed.MethodsWe carried out a genome‐wide association study (GWAS) meta‐analysis on (i) 478 GP patients from the National Institute of Diabetes and Digestive and Kidney Diseases Gastroparesis Clinical Research Consortium (GpCRC) compared to 9931 population‐based controls from the University of Michigan Health and Retirement Study; and (ii) 402 GP cases compared to 48,340 non‐gastroparesis controls from the Michigan Genomics Initiative. Associations for 5,811,784 high‐quality SNPs were tested on a total of 880 GP patients and 58,271 controls, using logistic mixed models adjusted for age, sex, and principal components. Gene mapping was obtained based on genomic position and expression quantitative trait loci, and a gene‐set network enrichment analysis was performed. Genetic associations with clinical data were tested in GpCRC patients. Protein expression of selected candidate genes was determined in full thickness gastric biopsies from GpCRC patients and controls.ResultsWhile no SNP associations were detected at strict significance (p ≤ 5 × 10−8), nine independent genomic loci were associated at suggestive significance (p ≤ 1 × 10−5), with the strongest signal (rs9273363, odds ratio = 1.4, p = 1 × 10−7) mapped to the human leukocyte antigen region. Computational annotation of suggestive risk loci identified 14 protein‐coding candidate genes. Gene‐set network enrichment analysis revealed pathways potentially involved in immune and motor dysregulation (pFDR ≤ 0.05). The GP risk allele rs6984536A (Peroxidasin‐Like; PXDNL) was associated with increased abdominal pain severity scores (Beta = 0.13, p = 0.03). Gastric muscularis expression of PXDNL also positively correlated with abdominal pain in GP patients (r = 0.8, p = 0.02). Dickkopf WNT Signaling Pathway Inhibitor 1 showed decreased expression in diabetic GP patients (p = 0.005 vs. controls).ConclusionWe report preliminary GWAS findings for GP, which highlight candidate genes and pathways related to immune and sensory‐motor dysregulation. Larger studies are needed to validate and expand these findings in independent datasets.

IMD0 and WLST were assessed for their clinical utility in assessing patients with symptoms of gastroparesis. Low IMD0 is associated with less gastric retention and less heartburn. Volume of water consumed during WLST, while associated with IMD0, has associations with early satiety, postprandial fullness, loss of appetite, and nausea. IMD0 and WLST appear to overlap somewhat in their assessment of gastric physiology in adults with symptoms of gastroparesis but relate to different dyspeptic symptoms.