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AbstractBackgroundAutonomic dysfunction can be present in patients with idiopathic and diabetic gastroparesis. The role of autonomic dysfunction relating to gastric emptying and upper gastrointestinal symptoms in patients with gastroparesis and chronic unexplained nausea and vomiting (CUNV) remains unclear. The aim of our study is to evaluate autonomic function in patients with gastroparesis and CUNV with respect to etiology, gastric emptying and symptom severity.MethodsWe studied 242 patients with chronic gastroparetic symptoms recruited at eight centers. All patients had a gastric emptying scintigraphy within 6 months of the study. Symptom severity was assessed using the gastroparesis cardinal symptom index. Autonomic function testing was performed at baseline enrollment using the ANX 3.0 autonomic monitoring system which measures heart rate variability and respiratory activity measurements.Key ResultsLow sympathetic response to challenge (Valsalva or standing) was the most common abnormality seen impacting 89% diabetic and 74% idiopathic patients. Diabetics compared to idiopathics, exhibited greater global hypofunction with sympathetic (OR = 4.7, 95% CI 2.2‐10.3; P < .001) and parasympathetic (OR = 7.2, 95% CI 3.4‐15.0; P < .001) dysfunction. Patients with delayed gastric emptying were more likely to have paradoxic parasympathetic excessive during sympathetic challenge [(Valsalva or standing) 40% vs. 26%, P = .05]. Patients with more severe symptoms exhibited greater parasympathetic dysfunction compared to those with mild‐moderate symptoms: resting sympathovagal balance [LFa/RFa 1.8 (1.0‐3.1) vs. 1.2 (0.6‐2.3), P = .006)] and standing parasympathetic activity [0.4 (0.1‐0.8) vs. 0.6 (0.2‐1.7); P = .03].ConclusionsAutonomic dysfunction was common in patients with gastroparesis and CUNV. Parasympathetic dysfunction was associated with delayed gastric emptying and more severe upper gastrointestinal symptoms. Conversely, sympathetic hypofunction was associated with milder symptoms.InferencesGastroparesis and CUNV may be a manifestation of GI autonomic dysfunction or imbalance, such that sympathetic dysfunction occurs early on in the manifestation of chronic upper GI symptoms, while parasympathetic dysfunction results in more severe symptoms and delayed gastric emptying.

OBJECTIVES: Diabetic gastroparesis (Gp) occurs more often in type 1 diabetes mellitus (T1DM) than in type 2 diabetes mellitus (T2DM). Other diabetic end-organ complications include peripheral neuropathy, nephropathy, and retinopathy (together termed triopathy ). This study determines the prevalence of diabetic complications (retinopathy, nephropathy, and peripheral neuropathy) in diabetic patients with symptoms of Gp, assessing the differences between T1DM and T2DM and delayed and normal gastric emptying (GE). METHODS: Diabetic patients with symptoms of Gp underwent history and physical examination, GE scintigraphy, electrogastrography with water load, autonomic function testing, and questionnaires assessing symptoms and peripheral neuropathy. RESULTS: One hundred thirty-three diabetic patients with symptoms of Gp were studied: 59 with T1DM and 74 with T2DM and 103 with delayed GE and 30 without delayed GE. The presence of retinopathy (37% vs 24%; P = 0.13), nephropathy (19% vs 11%; P = 0.22), and peripheral neuropathy (53% vs 39%; P = 0.16) was not significantly higher in T1DM than in T2DM; however, triopathies (all 3 complications together) were seen in 10% of T1DM and 3% of T2DM ( P = 0.04). Diabetic patients with delayed GE had increased prevalence of retinopathy (36% vs 10%; P = 0.006) and number of diabetic complications (1.0 vs 0.5; P = 0.009); however, 39% of diabetic patients with delayed GE did not have any diabetic complications. DISCUSSION: In diabetic patients with symptoms of Gp, delayed GE was associated with the presence of retinopathy and the total number of diabetic complications. Only 10% of patients with T1DM and 3% of those with T2DM had triopathy of complications, and 39% of diabetic patients with Gp did not have any diabetic complications. Thus, the presence of diabetic complications should raise awareness for Gp in either T1DM or T2DM; however, diabetic Gp frequently occurs without other diabetic complications.

Abstract Background Gastric electrical stimulation (GES) for treating gastroparesis symptoms is controversial. Methods We studied 319 idiopathic or diabetic gastroparesis symptom patients from the Gastroparesis Clinical Research Consortium (GpCRC) observational studies: 238 without GES and 81 with GES. We assessed the effects of GES using change in GCSI total score and nausea/vomiting subscales between baseline and 48 weeks. We used propensity score methods to control for imbalances in patient characteristics between comparison groups. Key Results GES patients were clinically worse (40% severe vs. 18% for non‐GES; P < .001); worse PAGI‐QOL (2.2. vs. 2.6; P = .003); and worse GCSI total scores (3.5 vs. 2.8; P < .001). We observed improvements in 48‐week GCSI total scores for GES vs. non‐GES: improvement by ≥ 1‐point (RR = 1.63; 95% CI = (1.14, 2.33); P = .01) and change from enrollment (difference = −0.5 (−0.8, −0.3); P < .001). When adjusting for patient characteristics, symptom scores were smaller and not statistically significant: improvement by ≥ 1‐point (RR = 1.29 (0.88, 1.90); P = .20) and change from the enrollment (difference = −0.3 (−0.6, 0.0); P = .07). Of the individual items, the nausea improved by ≥ 1 point (RR = 1.31 (1.03, 1.67); P = .04). Patients with GCSI score ≥ 3.0 tended to improve more than those with score < 3.0. (Adjusted P = 0.02). Conclusions and Inferences This multicenter study of gastroparesis patients found significant improvements in gastroparesis symptoms among GES patients. Accounting for imbalances in patient characteristics, only nausea remained significant. Patients with greater symptoms at baseline improved more after GES. A much larger sample of patients is needed to fully evaluate symptomatic responses and to identify patients likely to respond to GES.

Abstract Background Symptoms induced by caloric or non‐caloric satiety test meals and gastric myoelectrical activity (GMA) have not been studied in patients with diabetic gastroparesis (DGP) before and after intense glucose management. Aims We determined the effects of continuous subcutaneous insulin infusion (CSII) with continuous glucose monitoring (CGM) on GI symptoms, volume consumed, and GMA induced by the caloric meal satiety test (CMST) and water load satiety test (WLST) in DGP. Methods Forty‐five patients with DGP underwent CMST and WLST at baseline and 24 weeks after CSII with CGM. Subjects ingested the test meals until they were completely full. Visual analog scales were used to quantify pre‐ and postmeal symptoms, and GMA was recorded with cutaneous electrodes and analyzed visually and by computer. Key Results At baseline and 24‐week visits, nausea, bloating, abdominal discomfort, and fullness were immediately increased after CMST and WLST (Ps < 0.01). The meal volumes ingested were significantly less than normal controls at both visits in almost one‐third of the subjects. After the CMST, the percentage 3 cycle per minute GMA increased and bradygastria decreased compared with WLST (Ps < 0.05). After treatment for 24 weeks meal volumes ingested, postmeal symptoms and GMA were no different than baseline. Conclusions and inferences (a) Satiety test meals elicited symptoms of nausea, bloating, and abdominal discomfort; (b) CMST stimulated more symptoms and changes in GMA than WLST; and (c) CSII with CGM for 24 weeks did not improve symptoms, volumes ingested, or GMA elicited by the two satiety test meals in these patients with diabetic GP. Satiety tests in diabetic gastropresis are useful to study acute postprandial symptoms and GMA, but these measures were not improved by intensive insulin therapy.

Macrophage-based immune dysregulation plays a critical role in development of delayed gastric emptying in diabetic mice. Loss of anti-inflammatory macrophages and increased expression of genes associated with pro-inflammatory macrophages has been reported in full-thickness gastric biopsies from gastroparesis patients. We aimed to determine broader protein expression (proteomics) and protein-based signaling pathways in gastric biopsies of diabetic (DG) and idiopathic gastroparesis (IG) patients. Additionally, we determined correlations between protein expressions, gastric emptying, and symptoms. Full-thickness gastric antrum biopsies were obtained from nine DG patients, seven IG patients, and five nondiabetic controls. Aptamer-based SomaLogic tissue scan that quantitatively identifies 1,305 human proteins was used. Protein fold changes were computed, and differential expressions were calculated using Limma. Ingenuity pathway analysis and correlations were carried out. Multiple-testing corrected P < 0.05 was considered statistically significant. Seventy-three proteins were differentially expressed in DG, 132 proteins were differentially expressed in IG, and 40 proteins were common to DG and IG. In both DG and IG, “Role of Macrophages, Fibroblasts and Endothelial Cells” was the most statistically significant altered pathway [DG false discovery rate (FDR) = 7.9 × 10−9; IG FDR = 6.3 × 10−12]. In DG, properdin expression correlated with GCSI bloating ( r = −0.99, FDR = 0.02) and expressions of prostaglandin G/H synthase 2, protein kinase C-ζ type, and complement C2 correlated with 4 h gastric retention ( r = −0.97, FDR = 0.03 for all). No correlations were found between proteins and symptoms or gastric emptying in IG. Protein expression changes suggest a central role of macrophage-driven immune dysregulation in gastroparesis, specifically, complement activation in diabetic gastroparesis. NEW & NOTEWORTHY This study uses SOMAscan, a novel proteomics assay for determination of altered proteins and associated molecular pathways in human gastroparesis. Seventy-three proteins were changed in diabetic gastroparesis, 132 in idiopathic gastroparesis compared with controls. Forty proteins were common in both. Macrophage-based immune dysregulation pathway was most significantly affected in both diabetic and idiopathic gastroparesis. Proteins involved in the complement and prostaglandin synthesis pathway were associated with symptoms and gastric emptying delay in diabetic gastroparesis.

AbstractBackgroundThe purpose of this study was to evaluate the measurement properties of the American Neurogastroenterology and Motility Society Gastroparesis Cardinal Symptom Index‐Daily Diary, a patient‐reported outcome instrument developed to meet US FDA recommendations for a symptom‐based clinical trial endpoint in gastroparesis. The ANMS GCSI‐DD assesses nausea, early satiety, postprandial fullness, and upper abdominal pain on a severity score from none (0) to very severe (4) and number of vomiting episodes during the past 24 hours. The composite score includes the first four symptoms, the core symptom score includes all five symptoms.MethodsSeventy‐one patients diagnosed with idiopathic or diabetic gastroparesis were recruited for a four‐week observational study. Patients completed the ANMS GCSI‐DD at home between Baseline and Week 4. Statistical analyses included confirmatory factor analysis, item response theory analysis, internal consistency, test‐retest reliability, and construct and known‐groups validity.Key ResultsUnidimensionality for the composite and core symptom scores was supported, and items exhibited good fit. Internal consistency (Cronbach's alpha =0.85 and 0.83) and test‐retest reliability were 0.89 and 0.88, for composite and core symptom scores, respectively. Convergent validity was supported by strong correlations with patient‐reported and clinician measures. Baseline and Week 4 scores differed for three measures used to define disease severity status (P < 0.0001), supporting known‐groups validity.Conclusions & InferencesThe ANMS GCSI‐DD has excellent reliability and validity, supporting its use to assess symptom‐based endpoints in gastroparesis clinical studies. Further analyses will be conducted using clinical trial data to ascertain treatment responsiveness and define a responder.

The aims of these experiments were to determine in vitro whether colonic distension releases acetylcholine, vasoactive intestinal polypeptide (VIP), and substance P in the guinea pig inferior mesenteric ganglia (IMG) and whether cholinergic and peptidergic mechanosensory nerves projecting from the colon to the IMG receive cholinergic input from other enteric neurons. Colonic distension significantly increased the release of [3H]-acetylcholine, VIP-like immunoreactivity, and substance P-like immunoreactivity in the IMG. Nicotinic receptor blockade in the colon diminished the increase in [3H]acetylcholine release, abolished the increase in VIP-like immunoreactivity release during distension, but had no effect on the release of substance P-like immunoreactivity. Nicotinic receptor blockade in the colon also decreased fast mechanosensory input and significantly reduced by 54% the slow excitatory postsynaptic potential amplitude evoked by colonic distension. The data suggest that enteric cholinergic and VIP mechanosensory neurons that project from the colon to sympathetic neurons in the IMG receive peripheral cholinergic input from other enteric neurons. There was no evidence for enteric cholinergic input to the mechanosensory substance P pathway.

Abstract Background Wireless motility capsule ( WMC ) findings are incompletely defined in suspected gastroparesis. We aimed to characterize regional WMC transit and contractility in relation to scintigraphy, etiology, and symptoms in patients undergoing gastric emptying testing. Methods A total of 209 patients with gastroparesis symptoms at NIDDK Gastroparesis Consortium centers underwent gastric scintigraphy and WMC s on separate days to measure regional transit and contractility. Validated questionnaires quantified symptoms. Key Results Solid scintigraphy and liquid scintigraphy were delayed in 68.8% and 34.8% of patients; WMC gastric emptying times ( GET ) were delayed in 40.3% and showed 52.8% agreement with scintigraphy; 15.5% and 33.5% had delayed small bowel ( SBTT ) and colon transit ( CTT ) times. Transit was delayed in ≥2 regions in 23.3%. Rapid transit was rarely observed. Diabetics had slower GET but more rapid SBTT versus idiopathics ( P ≤ .02). GET delays related to greater scintigraphic retention, slower SBTT , and fewer gastric contractions ( P ≤ .04). Overall gastroparesis symptoms and nausea/vomiting, early satiety/fullness, bloating/distention, and upper abdominal pain subscores showed no relation to WMC transit. Upper and lower abdominal pain scores ( P ≤ .03) were greater with increased colon contractions. Constipation correlated with slower CTT and higher colon contractions ( P = .03). Diarrhea scores were higher with delayed SBTT and CTT ( P ≤ .04). Conclusions & Inferences Wireless motility capsules define gastric emptying delays similar but not identical to scintigraphy that are more severe in diabetics and relate to reduced gastric contractility. Extragastric transit delays occur in >40% with suspected gastroparesis. Gastroparesis symptoms show little association with WMC profiles, although lower symptoms relate to small bowel or colon abnormalities.

AbstractBackgroundAnimal studies have increasingly highlighted the role of macrophages in the development of delayed gastric emptying. However, their role in the pathophysiology of human gastroparesis is unclear. Our aim was to determine changes in macrophages and other cell types in the gastric antrum muscularis propria of patients with diabetic and idiopathic gastroparesis.MethodsFull thickness gastric antrum biopsies were obtained from patients enrolled in the Gastroparesis Clinical Research Consortium (11 diabetic, 6 idiopathic) and 5 controls. Immunolabeling and quantitative assessment was done for interstitial cells of Cajal (ICC) (Kit), enteric nerves protein gene product 9.5, neuronal nitric oxide synthase, vasoactive intestinal peptide, substance P, tyrosine hydroxylase), overall immune cells (CD45) and anti‐inflammatory macrophages (CD206). Gastric emptying was assessed using nuclear medicine scintigraphy and symptom severity using the Gastroparesis Cardinal Symptom Index.ResultsBoth diabetic and idiopathic gastroparesis patients showed loss of ICC as compared to controls (Mean [standard error of mean]/hpf: diabetic, 2.28 [0.16]; idiopathic, 2.53 [0.47]; controls, 6.05 [0.62]; P=.004). Overall immune cell population (CD45) was unchanged but there was a loss of anti‐inflammatory macrophages (CD206) in circular muscle (diabetic, 3.87 [0.32]; idiopathic, 4.16 [0.52]; controls, 6.59 [1.09]; P=.04) and myenteric plexus (diabetic, 3.83 [0.27]; idiopathic, 3.59 [0.68]; controls, 7.46 [0.51]; P=.004). There was correlation between the number of ICC and CD206‐positive cells (r=.55, P=.008). Enteric nerves (PGP9.5) were unchanged: diabetic, 33.64 (3.45); idiopathic, 41.26 (6.40); controls, 46.80 (6.04).ConclusionLoss of antral CD206‐positive anti‐inflammatory macrophages is a key feature in human gastroparesis and it is associates with ICC loss.