Involvement of oxidative stress-AMPK-Cx43-NLRP3 pathway in extracellular matrix remodeling of gastric smooth muscle cells in rats with diabetic gastroparesis.

This study aimed to investigate the changes in oxidative stress, adenosine monophosphate-activated protein kinase (AMPK), connexin43 (Cx43), nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) expression, and extracellular matrix (ECM) in the gastric smooth muscle tissues of rats with diabetic gastroparesis (DGP) and high glucose-cultured gastric smooth muscle cells, determine the existence of oxidative stress-AMPK-Cx43-NLRP3 pathway under high glucose condition, and the involvement of this pathway in ECM remodeling in DGP rats. The results showed that with increasing duration of diabetes, oxidation stress levels gradually increased, the AMPK activity decreased first and then increased, NLRP3, CX43 expression, and membrane/cytoplasm ratio of Cx43 expression were increased in the gastric smooth muscle tissues of diabetic rats. Changes in ECM of gastric smooth muscle cells were observed in DGP rats. The DGP group showed higher collagen type I content, increased expression of Caspase-1, transforming growth factor-beta 3 (TGF-ß3), and matrix metalloproteinase-2 (MMP-2), decreased tissue inhibitor of metalloproteinase-1 (TIMP-1) expression, and higher interleukin-1 beta content when compared with the control group. For gastric smooth muscle cells cultured under higher glucose, the MMP-2 and TGF-ß3 expression was decreased, TGF-ß1 and TIMP-1 expression was increased, the interleukin-1 beta content was decreased in cells after inhibition of NLRP3 expression; the NLRP3 and Caspase-1 expression was decreased, and adenosine triphosphate content was lower after inhibition of Cx43; the expression of NLRP3, Caspase-1, P2X7, and the membrane/cytoplasm ratio of CX43 expression was decreased in cells after inhibition of AMPK and oxidative stress, the phospho-AMPK expression was also decreased after suppressing oxidative stress. Our findings suggest that high glucose induced the activation of the AMPK-Cx43-NLRP3 pathway through oxidative stress, and this pathway was involved in the ECM remodeling of gastric smooth muscles in DGP rats by regulating the biological functions of TGF-ß3, TGF-ß1, MMP-2, and TIMP-1.

Validity of Endoscopic Submucosal Dissection for Gastric Cancer Diagnosed as Differentiated Adenocarcinoma Before Treatment Regardless of Lesion Size.

BACKGROUND/AIMS: We investigated the validity and safety of endoscopic submucosal dissection for gastric tumors by examining shortand long-term outcomes by tumor diameter. MATERIALS AND METHODS: Endoscopic submucosal dissection for gastric tumor was performed on 4259 lesions at our hospital between January 2005 and June 2021. [Study 1] Patients were divided into 5 tumor diameter groups: 3751 lesions, ≤30 mm; 366 lesions, 31-50 mm; 106 lesions, 51-75 mm; 24 lesions, 76-100 mm; and 12 lesions, ≥101 mm. Short-term gastric endoscopic submucosal dissection outcomes were investigated. [Study 2] Long-term outcomes (delayed gastric emptying and prognosis) were investigated in 508 cases with tumor diameter ≥31 mm. RESULTS: [Study 1] Perforation rate (%) was 1.2, 3.6, 3.8, 12.5, and 25.0 for lesions with tumor diameter ≤30 mm, in the range 31-50 mm, 51-75 mm, and 76-100 mm, and ≥101 mm, respectively. Postoperative bleeding rate (%) was 4.8, 9.0, 6.6, 20.8, and 33.3, respectively, R0 resection rate (%) was 96.8, 90.2, 89.6, 70.8, and 66.6, respectively, and curative resection rate (%) was 92.0, 61.2, 63.2, 45.8, and 8.3, respectively. [Study 2] There were 7 cases of delayed gastric emptying after wide resection, with 3 patients requiring balloon dilatation, 1 of whom subsequently underwent distal gastrectomy. Among 205 cases of noncurative resection, 110 underwent additional surgery, residual cancer was present in 11 cases, and lymph node metastasis was observed in 7 cases (1 patient died of disease). To date, 1 of the 95 patients being followed up has died of disease (mean follow-up: 2042 days). CONCLUSION: Even with a tumor diameter ≥31 mm, curative resection was achieved in about 60% of cases in which intramucosal lesions were considered possible preoperatively, but the rate was low at 8.3% for tumor diameter ≥101 mm. Long-term outcomes appear favorable, with only 0.4% of the patients dying of disease but delayed gastric emptying observed in 1.7% of cases.

Quantification of Interstitial Cells of Cajal in the Gastric Muscle of Patients with Gastroparesis at Per-Oral Endoscopic Pyloromyotomy: A Novel Approach for Future Research in Pathogenesis of Gastroparesis.

BACKGROUND: The role of Interstitial Cells of Cajal (ICC) in the pathogenesis of gastroparesis has been suggested by previous studies due to their involvement in the transmission of neuronal signaling to the smooth muscles of the GI tract. However, studies have been limited by the inability to obtain a gastric muscle sample, since routine endoscopy can only biopsy the mucosa. We present a new technique of muscle biopsy during per-oral endoscopic pyloromyotomy (GPOEM), a novel endoscopic procedure for treatment of gastroparesis. PATIENTS AND METHODS: All enrolled patients had diagnosed gastroparesis and had biopsies of the muscular layer at the antrum/pylorus during POEM. All GPOEM procedures took place from August 2019 to December 2019. Various demographic, disease-related, and procedure-related data were collected from chart review. ICC in the biopsy specimen was examined and quantitated. RESULTS: Through this method, we readily expose the gastric muscle of 21 patients through dissection of a gastric submucosal tunnel during GPOEM and provide reliable muscle sample for ICC quantification. Average number of ICC were higher in clinical responders (88 ICC ± 63 vs. 39 ICC ± 24, p = 0.02), defined as those who experienced significant improvement in nausea and vomiting symptoms after GPOEM. CONCLUSIONS: This study provides a reliable novel biopsy method for safely biopsy gastric muscle for quantitating the number of gastric ICC in patients with gastroparesis. The number of ICC may be related to the outcome of GPOEM therapy. However, further studies with larger number of patients are needed to confirm the results.

Gastric ablation as a novel technique for modulating electrical conduction in the in vivo stomach.

Gastric motility is coordinated by underlying bioelectrical "slow wave" activity. Slow wave dysrhythmias are associated with motility disorders, including gastroparesis, offering an underexplored potential therapeutic target. Although ablation is widely used to treat cardiac arrhythmias, this approach has not yet been trialed for gastric electrical abnormalities. We hypothesized that ablation can create localized conduction blocks and modulate slow wave activation. Radiofrequency ablation was performed on the porcine serosa in vivo, encompassing a range of parameters (55-85°C, adjacent points forming a line, 5-10 s/point). High-resolution electrical mapping (16 × 16 electrodes; 6 × 6 cm) was applied to define baseline and acute postablation activation patterns. Tissue damage was evaluated by hematoxylin and eosin and c-Kit stains. Results demonstrated that RF ablation successfully induced complete conduction block and a full thickness lesion in the muscle layer at energy doses of 65-75°C for 5-10 s/point. Gastric ablation may hold therapeutic potential for gastric electrical abnormalities in the future.NEW & NOTEWORTHY This study presents gastric ablation as a new method for modulating slow wave activation and propagation in vivo, by creating localized electrical conduction blocks in the stomach, validated by high-resolution electrical mapping and histological tissue analysis. The results define the effective energy dose range for creating conduction blocks, while maintaining the mucosal and submucosal integrity, and demonstrate the electrophysiological effects of ablation. In future, gastric ablation can now be translated toward disrupting dysrhythmic slow wave activation.

Gastric Biopsies in Gastroparesis: Insights into Gastric Neuromuscular Disorders to Aid Treatment.

The cellular and molecular understanding of human gastroparesis has markedly improved due to studies on full-thickness gastric biopsies. A decrease in the number of interstitial cells of Cajal (ICC) and functional changes in ICC constitutes the hallmark cellular feature of gastroparesis. More recently, in animal models, macrophages have also been identified to play a central role in development of delayed gastric emptying. Activation of macrophages leads to loss of ICC. In human gastroparesis, loss of anti-inflammatory macrophages in gastric muscle has been shown. Deeper molecular characterization using transcriptomics and proteomics has identified macrophage-based immune dysregulation in human gastroparesis.

Risk factors and prognosis of gastric stasis, a crucial problem after laparoscopic pylorus-preserving gastrectomy for early middle-third gastric cancer.

BACKGROUND: Pylorus-preserving gastrectomy (PPG) is a function-preserving procedure for cT1N0 gastric cancer located in the middle-third of stomach, which is currently performed through a laparoscopic approach (LPPG). PPG is sometimes associated with a crucial problem during the early postoperative course, designated gastric stasis. However, information regarding gastric stasis remains to be fully elucidated. METHODS: The study included 897 patients who underwent LPPG between 2005 and 2017. Early postoperative gastric stasis (E-stasis) was defined when the following conditions were fulfilled: upper abdominal distension, remnant stomach fullness on radiography image, and period of starvation exceeding 72 h within 1 month postoperatively. To evaluate long-term outcomes of E-stasis, late postoperative food residue (L-residue) was defined as grade 2 or higher food residue endoscopically according to the RGB (residue, gastritis, bile) classification at 1 year postoperatively. Risk factors and long-term outcomes of E-stasis were retrospectively analyzed. RESULTS: E-stasis was the most common complication during the early postoperative course. E-stasis occurred in 68 (7.6%) patients. Multivariate analysis identified age (≥ 61 years), DM, and postoperative intraabdominal infection as risk factors. At 1 year postoperatively, relative body weight ratio and postoperative serum albumin in the patients who experienced E-stasis was significantly lower than those in the other patients (P = 0.042 and 0.011, respectively). Of the patients who suffered from E-stasis, 42.5% experienced L-residue. CONCLUSIONS: E-stasis after LPPG occurs in 7.6% of patients. Age, DM, and intraabdominal infection are significantly related to E-stasis. E-stasis is associated with poorer nutritional and functional outcomes even at 1 year postoperatively.

Mechanism of CNP-mediated DG-PKC and IP4 signaling pathway in diabetic rats with gastric motility disorder.

In the precedent research conducted by the same team, it concluded that the activities in C-type natriuretic peptide (CNP)/cyclic guanosine monophosphate (cGMP)/cyclic adenosine monophosphate (cAMP)/ß-type phospholipase C (PLCß) pathways of rat antral smooth muscle were changed due to diabetes, which was the key pathogenetic mechanism for diabetic gastric dysmotility. As the follow-on step, this study was designed to probe into the downstream signaling pathway of CNP/PLCß. The results showed that level of α-type protein kinase C (PKCα),cell membrane to cytoplasm ratio of PKCα, cell membrane to cytoplasmic ratio of ßI-type protein kinase C (PKCßI) and level of Phosphor-PKCα (P-PKCα) were significantly reduced in diabetes rat antral smooth muscle samples. The content of tetraphosphate inositol (IP4) in gastric antral smooth muscle of diabetic rats reduced, and the content of diacyl-glycerol (DG) was unchanged. CNP significantly decreased the content of IP4 and DG, this effect was more obvious in diabetic rats. Subsequent to the addition of protein kinase A (PKA) blocker N-[2- (p-Bromocin-namylamino)ethyl]-5 -isoquinolinesulfonamide dihydrochloride (H-89) before CNP treatment, the inhibitory effect of CNP was reduced; subsequent to the addition of protein kinase G (PKG) blocker KT5823 before CNP treatment, the inhibitory effect of CNP was also reduced. With the addition of the combination of H-89 and KT5823 before CNP treatment, the inhibition by CNP could be offset. These results were concluded that CNP inhibited the activity of PKC family in rat smooth muscle and reduced the levels of IP4 and DG through the PKG/PKA-PLCß pathways, causing inhibited muscular contractions, which may be a key pathogenetic factor for diabetic gastroparesis.

Effects of AMPK on Apoptosis and Energy Metabolism of Gastric Smooth Muscle Cells in Rats with Diabetic Gastroparesis.

This study aimed to investigate the effect of AMPK on apoptosis and energy metabolism of gastric smooth muscle cells in diabetic rats and to explore the role of AMPK in the pathogenesis of diabetic gastroparesis (DGP). After establishment of a diabetic rat model, rats were divided into normal control (NC), 4-week (DM4W), 6-week (DM6W), and 8-week (DM8W) diabetic model groups. The gastric residual pigment ratio, intestinal transit rate, and intestinal propulsion rate in each group were detected to confirm the successful establishment of the DGP model. The spontaneous contraction in isolated gastric smooth muscle strips of the NC and DM8W groups was experimentally observed. The expression of phospho-AMPK, AMPK, phospho-LKB1, LKB1, phospho-TAK1, TAK1, and CaMMKß in rat gastric smooth muscle tissues was detected by western blot analysis; ADP, AMP, ATP contents, and the energy charge were detected using Elisa; and apoptosis of gastric smooth muscle cells was detected by flow cytometry. The rat gastric smooth muscle cells were cultured in vitro, and treated with an AMPK inhibitor and an agonist. At 24 and 48 h, the effects of AMPK on apoptosis and energy metabolism of gastric smooth muscle cells were observed. Reduced spontaneous contractions, AMPK activation, cell apoptosis, and energy metabolism disorders were observed in gastric smooth muscle tissues of a diabetic rat, and AMPK activation was associated with an increased ratio of ADP/ATP, AMP/ATP, LKB1 activity, and CaMMKß expression. From in vitro cell culture experiments, we found that AMPK activation of high-glucose conditions promoted cell apoptosis. Inhibition of AMPK had no obvious effect on apoptosis at the early stage with high glucose, but the inhibitory effect was significant at the late stage with high glucose. AMPK can regulate both mitochondrial metabolism and glycolysis pathways under high-glucose conditions. During the early stage with high glucose, AMPK was the main promotion factor of the mitochondrial metabolism pathway, but did not increase the ATP production, AMPK also promoted the glycolysis pathway. During the late stage with high glucose, AMPK was a major inhibitor of the mitochondrial pathway, and still played a role in promoting the glycolytic pathway, which acted as the main regulator. Apoptosis and energy metabolism disorders were present in gastric smooth muscle cells during the occurrence of DGP. Under high-glucose condition, AMPK was activated, which can promote apoptosis, change the energetic metabolism pathway of cells, inhibit mitochondrial energy metabolism, and promote glycolysis.

Segmental zoster abdominal paresis mimicking an abdominal hernia: A case report and literature review.

RATIONALE: Herpes zoster infection typically involves the posterior root ganglia and most of the symptoms are sensory. Motor involvement can occur in the same distribution but is relatively uncommon. Segmental zoster paresis is a rare motor complication of Herpes zoster, mimicking an abdominal hernia, but it needs no surgery different from the real abdominal wall hernia. PATIENT CONCERNS: We present a case of a 58-year-old man with an abdominal protrusion and characteristical herpes zoster rash. DIAGNOSES: Initially, the surgeon regarded it as an abdominal hernia, while ultrasonography excluded the abdominal wall defect, and then the dermatologist diagnosed it as segmental herpes zoster abdominal paralysis. INTERVENTIONS: He received a treatment with oral acyclovir, mecobalamin, and vitamin B1. OUTCOMES: The abdominal wall bulge disappeared after 2 months, avoiding unnecessary surgery. LESSONS: Segmental zoster abdominal paresis, mimicking an abdominal hernia needs no surgery.

Gastroparesis is associated with decreased FOXF1 and FOXF2 in humans, and loss of FOXF1 and FOXF2 results in gastroparesis in mice.

BACKGROUND AND AIMS: The transcription factors FOXF1 and FOXF2 have been implicated in the development of the gastrointestinal tract but their role in adults or in gastrointestinal diseases is poorly understood. We have recently shown that expression of serum response factor (SRF), a transcription factor whose activity is modulated by FOXF proteins, is decreased in the stomach muscularis of patients with gastroparesis. The aim of the current study was to determine whether FOXF expression is decreased in gastroparesis patients and whether loss of FOXF1 and/or FOXF2 from adult smooth muscle is sufficient to impair gastric emptying in mice. METHODS: Full-thickness stomach biopsy samples were collected from control subjects and from patients with gastroparesis. mRNA was isolated from the muscularis externa, and FOXF mRNA expression levels were determined by quantitative reverse transcriptase (RT)-PCR. Foxf1 and Foxf2 were knocked out together and separately from smooth muscle cells in adult mice, and the subsequent effect on liquid gastric emptying and contractile protein expression was determined. KEY RESULTS: Expression of FOXF1 and FOXF2 is decreased in smooth muscle tissue from gastroparesis patients. Knockout of Foxf1 and Foxf2 together, but not alone, from mouse smooth muscle resulted in delayed liquid gastric emptying. Foxf1/2 double knockout mice had decreased expression of smooth muscle contractile proteins, SRF, and myocardin in stomach muscularis. CONCLUSIONS AND INFERENCES: Our findings suggest that decreased expression of FOXF1 and FOXF2 may be contributing to the impaired gastric emptying seen in gastroparesis patients.

Gastric Peroral Endoscopic Pyloromyotomy Reduces Symptoms, Increases Quality of Life, and Reduces Health Care Use For Patients With Gastroparesis.

BACKGROUND & AIMS: Gastric peroral endoscopic pyloromyotomy (GPOEM) is becoming a promising treatment option for patients with refractory gastroparesis. We aimed to systematically assess the efficacy of GPOEM and its effects on health care use. METHODS: We performed a retrospective study on 30 patients with refractory gastroparesis who underwent GPOEM from June 2015 through July 2017 at a tertiary center. We compared outcomes with those of 7 patients with refractory gastroparesis who did not undergo the procedure (controls). The primary outcomes were patient-reported reductions in symptoms, based on the gastroparesis cardinal symptom index (GCSI), and increases in 8 aspects of quality of life, based on Short Form 36 (SF-36) scores. Data were collected on the day of the procedure (baseline) and at 1 month, 6 months, 12 months, and 18 months afterward. Secondary outcomes included visits to the emergency department or hospitalization for gastroparesis-related symptoms. RESULTS: GPOEM was technically successful in all patients and significantly reduced GCSI scores in repeated-measure analysis of variance (F2.044, 38.838 = 22.319; P < .0005). The mean score at baseline was 3.5 ± 0.6, at 1 month after GPOEM was 1.8 ± 1.0 (P < .0005), at 6 months after was 1.9 ± 1.2 (P < .0005), at 12 months after was 2.6 ± 1.5 (P < .026), and at 18 months after was 2.1 ± 1.3 (P < .016). GPOEM was associated with improved quality of life: 77.8%, 76.5%, and 70% of patients had significant increases in SF-36 scores, compared with baseline, at 1 month, 6 months, and 12 months after GPOEM, respectively (F1.71,18.83 = 14.16; P < .0005). Compared with controls, patients who underwent GPOEM had significant reductions in GCSI, after we controlled for baseline score and duration of the disease (F1,31 = 9.001; P = .005). Patients who received GPOEM had significant reductions in number of emergency department visits (from 2.2 ± 3.1 times/mo at baseline to 0.3 ± 0.8 times/mo; P = .003) and hospitalizations (from 1.7 ± 2 times/mo at baseline to 0.2 ± 0.4 times/mo; P = .0002). CONCLUSIONS: In a retrospective study of patients who underwent GPOEM for refractory gastroparesis, we found the procedure significantly improved symptoms, increased quality of life, and reduced health care use related to gastroparesis.

Pathological Findings of the Antral and Pyloric Smooth Muscle in Patients with Gastroparesis-Like Syndrome Compared to Gastroparesis: Similarities and Differences.

BACKGROUND: Gastroparesis (GP)-like syndrome presents with the symptoms of GP but without delayed gastric emptying (GE). Whether GP-like syndrome is part of a spectrum of GP is not clear. This study aimed to compare the histopathological features of antral and pyloric smooth muscle tissue in GP and GP-like syndrome. METHODS: Full-thickness antral and/or pyloric biopsies were obtained from 37 GP and 18 GP-like syndrome patients who underwent abdominal surgery to place a gastric electrical stimulator or jejunal feeding tube and/or pyloroplasty. The tissues were stained with H&E, C-Kit, and trichrome. Based on previous control data, an interstitial cells of Cajal (ICC) count of <10 per high power field in the antrum and/or pylorus was considered depletion. Baseline total symptom score (TSS) was recorded. RESULTS: Twenty-four GP and 7 GP-like patients had pyloric biopsies. Pyloric ICC loss was observed in 20/24 (83.3%) GP and 2/7 (28.6%) GP-like patients (p < 0.01). Fibrosis was detected in the pyloric tissue of 20/24 (83.3%) GP and 2/7 (28.6%) GP-like patients who had pyloric trichrome staining (p < 0.01). Seventeen out of 24 (70.8%) GP patients with pyloric biopsies had concomitant pyloric ICC loss and fibrosis, while only one GP-like patient had ICC loss and simultaneous pyloric fibrosis. GP patients had a greater TSS compared to GP-like patients. In GP patients, those with pyloric ICC loss had a greater TSS compared to those with normal ICC. GP patients with pyloric fibrosis had a higher TSS compared to those without pyloric fibrosis. CONCLUSIONS: Compared to GP-like patients, the pyloric histopathological findings of ICC loss and fibrosis are common in GP and predict a greater symptom score. These pathological findings might be considered as markers of "pyloric dysfunction" and explain delayed GE in GP.

Significance of dynamic changes in gastric smooth muscle cell apoptosis, PI3K-AKT-mTOR and AMPK-mTOR signaling in a rat model of diabetic gastroparesis.

The aim of the present study was to investigate the significance of cell apoptosis, the phosphoinositide-3-kinase (PI3K)-protein kinase B (AKT)-mammalian target of rapamycin (mTOR) pathway, and the 5' adenosine monophosphate-activated protein kinase (AMPK)­mTOR pathways in the process of diabetic gastroparesis. Changes in gastric smooth muscle cells of diabetic rats with induced gastroparesis were examined. The diabetic rat model was established by dividing animals into a normal control group and diabetic model groups examined at 2, 4 and 6 weeks. Diabetic gastroparesis was evaluated by examining the rates of gastric residual pigment, whereas flow cytometry was used to detect the apoptosis of gastric smooth muscle cells. The expression levels of PI3K and phosphorylated (p­) AKT, AMPK, mTOR, tuberous sclerosis complex 2, p70 ribosomal S6 kinase, and eukaryotic translation initiation factor 4­binding protein 1 were determined in gastric muscles using western blot analysis. Diabetic gastroparesis was confirmed in models at 6 weeks. The apoptosis of gastric smooth muscle cells gradually increased in all diabetic groups, and significant changes were observed in key proteins involved in PI3K­AKT­mTOR and AMPK­mTOR signaling. The results indicated that apoptosis was important in the occurrence of diabetic gastroparesis, and the PI3K­AKT­mTOR and AMPK­mTOR pathways were activated during the apoptotic processes, but were incapable of regulating apoptosis.

Yield of Endoscopy in Pediatric Gastroparesis.

OBJECTIVES: The aim of the study was to quantify the diagnostic yield of upper endoscopy in children with gastroparesis and to develop a clinical model for gastroparesis using common symptoms and screening blood tests. METHODS: We retrospectively reviewed charts of 196 patients of age 4 to 18 years evaluated for gastroparesis between 2009 and 2013. All patients completed a standard solid-phase gastric emptying scan and upper endoscopy within a 12-month period. We analyzed gross and histologic endoscopy findings. Symptom-based data were collected on dyspeptic symptoms and classic "red-flag" symptoms. RESULTS: Seventy patients with gastroparesis and 126 controls were included. Clinically significant endoscopic findings were noted in 35% of controls (44/126) and 43% of gastroparetics (30/70), P = 0.345. Concordance between gross and histologic findings was low at 50%. Histologic findings included gastritis 60% (17/28), esophagitis 39% (11/28), and duodenitis 7% (2/28). In univariate and multivariate analyses, there was no meaningful correlation between symptoms and/or screening laboratory values and diagnosis of gastroparesis. CONCLUSIONS: Clinically significant endoscopy findings were common in both controls and gastroparetics. As more than one-third of patients had findings on endoscopy, we conclude that upper endoscopy remains an important part of the evaluation process of patients with dyspeptic symptoms and suspected gastroparesis. As gross abnormalities were frequently not present with histologic changes, routine biopsy is required. There was no association between studied symptoms and the presence of gastroparesis. A comprehensive evaluation of children with dyspeptic symptoms requires endoscopy with biopsy and solid-phase gastric emptying scan to determine the underlying diagnosis.

Gastric neuromuscular histology in patients with refractory gastroparesis: Relationships to etiology, gastric emptying, and response to gastric electric stimulation.

BACKGROUND: The aims of this study were to describe the histology in gastroparesis, specifically to relate histopathology to etiology of gastroparesis (idiopathic and diabetic gastroparesis), gastric emptying, and clinical response to gastric electric stimulation. METHODS: Full thickness gastric body sections obtained during insertion of gastric stimulator in gastroparetics were stained with Hematoxylin & Eosin, Masson Trichrome and immunohistochemical stains for Neuron-Specific Enolase and c-Kit. KEY RESULTS: In all, 145 gastroparetics (71 diabetics, 71 idiopathic, 2 post-surgical, and 1 chronic intestinal pseudo-obstruction) had full thickness gastric body biopsies. A lymphocytic infiltrate was seen in the intermyenteric plexus in 22 diabetic and 23 idiopathic gastroparesis patients. Fibrosis was present in the inner circular layer in 13 diabetic and 15 idiopathics and in the outer longitudinal layer in 46 diabetic and 51 idiopathics. Diabetic gastroparesis had less ganglion cells (3.27±1.82 vs 4.81±2.81/hpf; P<.01) and less ganglia (0.90±0.44 vs 1.10±0.50/hpf; P=.01) than idiopathic gastroparesis. Interstitial cells of Cajal (ICC) count was slightly lower in the inner circular layer in diabetic than idiopathics (2.77±1.47 vs 3.18±1.34/hpf; P=.08). Delayed gastric emptying was associated with reduced ICCs in the myenteric plexus. Global therapeutic response to gastric electric stimulation was inversely related to ganglia/hpf (R=-.22; P=.008). In diabetics, improvements in nausea, vomiting, and abdominal pain were inversely related to fibrosis. CONCLUSION AND INFERENCES: Histologic assessment of full thickness gastric biopsy specimens allows correlation of histopathology to the gastroparesis disease process, its etiology, gastric emptying, and response to gastric electric stimulation treatment.

Diabetic and idiopathic gastroparesis is associated with loss of CD206-positive macrophages in the gastric antrum.

BACKGROUND: Animal 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. METHODS: Full 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. RESULTS: Both 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). CONCLUSION: Loss of antral CD206-positive anti-inflammatory macrophages is a key feature in human gastroparesis and it is associates with ICC loss.

Innovative gastric endoscopic muscle biopsy to identify all cell types, including myenteric neurons and interstitial cells of Cajal in patients with idiopathic gastroparesis: a feasibility study (with video).

BACKGROUND AND AIMS: The pathophysiology of some GI neuromuscular diseases remains largely unknown. This is in part due to the inability to obtain ample deep gastric wall biopsies that include the intermuscular layer of the muscularis propria (MP) to evaluate the enteric nervous system, interstitial cells of Cajal (ICCs), and related cells. We report on a novel technique for gastric endoscopic muscle biopsy (gEMB). METHODS: Patients with idiopathic gastroparesis were prospectively enrolled in a feasibility study by using a novel "no hole" gEMB. Main outcome measures were technical success, adverse events, and histologic confirmation of the intermuscular layer, including myenteric neurons and ICC. The gEMB was a double resection clip-assist technique. A site was identified on the anterior wall of the gastric body as recommended by the International Working Group on histologic techniques. EMR was performed to unroof and expose the underlying MP. The exposed MP was then retracted into the cap of an over-the-scope clip. The clip was deployed, and the pseudopolyp of MP created was resected. This resulted in a no-hole gEMB. RESULTS: Three patients with idiopathic gastroparesis underwent gEMB. Patients had severe delayed gastric emptying with a mean (± standard deviation [SD]) of 49 ± 16.8% of retained gastric contents at 4 hours. They had no history of gastric or small-bowel surgery and did not use steroids or other immunosuppressive drugs. The gEMB procedure was successfully performed, with no procedural adverse events. Postprocedural abdominal pain was controlled with nonsteroidal anti-inflammatory agents and opioid analgesics. Mean length of resected MP was 10.3 ± 1.5 mm. Mean procedure time was 25.7 ± 6 minutes. Hematoxylin and eosin (H&E) staining of tissue samples confirmed the presence of both inner circular and outer longitudinal muscle, as well as the intermuscular layer. H&E staining showed reduced myenteric ganglia in 1 patient. In 2 patients, specialized immunohistochemistry was performed, which showed a marked decrease in myenteric neurons as delineated by an antibody to protein gene product 9.5 and a severe decrease in ICC levels across the muscle layers. At 1 month follow-up, upper endoscopy showed a well-healed scar in 2 patients and minimal ulceration with a retained clip in 1 patient. CT of the abdomen confirmed the integrity of the gastric wall in all patients. Because of lack of an immune infiltrate in the resected samples, patients were not considered suitable for immunosuppressive or steroid therapy. CONCLUSIONS: gEMB is feasible and easy to perform, with acquisition of tissue close to surgical samples to identify myenteric ganglia, ICCs, and multiple cell types. The ability to perform gEMB represents a paradigm shift in endoscopic tissue diagnosis of gastric neuromuscular pathologies.

Endoscopic approaches to gastroparesis.

PURPOSE OF REVIEW: This review covers the cause, evaluation and treatment options for gastroparesis. Symptoms of delayed gastric emptying are increasingly seen by gastroenterologists and gastrointestinal surgeons. Endoscopy - both laparoscopic and flexible - is increasingly important in treatment algorithms for this problem. RECENT FINDINGS: Gastroparesis is increasingly being seen in clinical practice. A progressive algorithm needs to be followed in these challenging cases: starting with medical treatment and diet modification, progressing through endoscopic treatments including new ones such as per-oral pyloromyotomy, and finally laparoscopic treatments including gastrectomy. SUMMARY: Endoscopic interventions are effective treatments for certain gastroparesis patients. New procedures offer a minimally invasive alternative to more radical options and should probably be more widely adopted.