Macrophages in diabetic gastroparesis--the missing link?

Common Pathophysiological Mechanisms and Treatment of Diabetic Gastroparesis

Diabetic gastroparesis (DGP) is a common complication of diabetes mellitus, marked by gastrointestinal motility disorder, a delayed gastric emptying present in the absence of mechanical obstruction. Clinical manifestations include postprandial fullness and epigastric discomfort, bloating, nausea, and vomiting. DGP may significantly affect the quality of life and productivity of patients. Research on the relationship between gastrointestinal dynamics and DGP has received much attention because of the increasing prevalence of DGP. Gastrointestinal motility disorders are closely related to a variety of factors including the absence and destruction of interstitial cells of Cajal, abnormalities in the neuro-endocrine system and hormone levels. Therefore, this study will review recent literature on the mechanisms of DGP and gastrointestinal motility disorders as well as the development of prokinetic treatment of gastrointestinal motility disorders in order to give future research directions and identify treatment strategies for DGP.

Chronic Electroacupuncture With High-Frequency at ST-36 Promotes Gastrointestinal Motility by Regulating Bone Morphogenetic Protein 2 Secretion of Muscularis Macrophages

BACKGROUND

Electroacupuncture (EA) at Zusanli (ST36) is an alternative treatment for several gastrointestinal motility disorders; however, the exact mechanism is unconfirmed. We aimed to show the potential effects of EA on muscularis macrophages (MMφ), the bone morphogenetic protein (BMP)/BMP receptor (BMPR)-Smad signal pathway, and enteric neurons in diabetic mice. This may provide fresh insight into ways EA affects gastrointestinal motility.

MATERIALS AND METHODS

C57BL/6J healthy adult male mice were randomly divided into five groups: regular control group, diabetes group, diabetes with sham EA group (acupuncture only), diabetes with low-frequency EA group (10 Hz), diabetes with high-frequency EA group (HEA) (100 Hz). The stimulation lasted eight weeks. Gastrointestinal motility was assessed. We identified M2-like MMφ in the layer of colonic muscle by flow cytometry. Western Blot, real-time polymerase chain reaction, and immunofluorescent staining were also used to determine the MMφ, molecules in the BMP2/BMPR-Smad pathway, and PGP9.5, neuronal nitric oxide synthase (nNOS) expression of enteric neurons in the colon of each group.

RESULTS

1) HEA improved the gastrointestinal motility (gastrointestinal transit time, defecation frequency) of diabetic mice. 2) HEA reversed the decreased proportion of M2-like MMφ and expression of the CD206 in the colon of diabetic mice. 3) HEA restored the downregulations of BMP2, BMPR1b, and Smad1 in the BMP2/BMPR-Smad pathway and increased downstream enteric neurons marked by PGP9.5, nNOS in the colon of diabetes mice.

CONCLUSIONS

HEA might promote gut dynamics by upregulating M2-like MMφ in the colon of diabetic mice, which in turn leads to the accumulation of molecules in the BMP2/BMPR-Smad signaling pathway and downstream enteric neurons.

"M1/M2" Muscularis Macrophages Are Associated with Reduction of Interstitial Cells of Cajal and Glial Cells in Achalasia

BACKGROUND AND AIMS

Several studies showed muscularis macrophages (MMφ) are associated with GI motility disorders. The purpose of this study was to preliminary explore the association between MMφ and achalasia.

METHODS

Tissue samples of the lower esophageal sphincter (LES) high-pressure zone were obtained from 27 achalasia patients and 10 controls. Immunohistochemistry for MMφ, interstitial cells of Cajal (ICC), neuronal nitric oxide synthase (nNOS), and glial cells were conducted. Histological characteristics were compared between groups, and correlation analysis was performed.

RESULTS

Fewer ICC was found in achalasia compared with controls (P = 0.018), and the level of M1 macrophages was higher than that in controls no matter in terms of the number or the proportion of M1(P = 0.026 for M1 and 0.037 for M1/MMφ). Statistical differences were found between two groups in terms of proportion of M2 and ratio of M1 to M2 (P = 0.048 for M2/ MMφ and < 0.001 for M1/M2). For the correlation analysis, significant correlations were detected between levels of nNOS, ICC, and glial cells in patients with achalasia (P = 0.026 for nNOS and ICC, 0.001 for nNOS and glial cells, 0.019 for ICC and glial cells). There were significant correlations between M2/MMφ and levels of ICC (P = 0.019), glial cells (P = 0.004), and nNOS (P = 0.135).

CONCLUSION

Patients with achalasia had a higher level of M1/M2 ratio in LES and significant correlations were found between M2/MMφ and numbers of ICC and glial cells, which suggested that MMφ were probably associated with occurrence and development of achalasia.

Novel insights into the pathogenic impact of diabetes on the gastrointestinal tract

Type 2 and type 1 diabetes are common endocrine disorders with a progressively increasing incidence worldwide. These chronic, systemic diseases have multiorgan implications, and the whole gastrointestinal (GI) tract represents a frequent target in terms of symptom appearance and interdependent pathophysiological mechanisms. Metabolic alterations linked with diabetic complications, neuropathy and disrupted hormone homeostasis can lead to upper and/or lower GI symptoms in up to 75% of diabetic patients, with multifactorial involvement of the oesophagus, stomach, upper and lower intestine, and of the gallbladder. On the other hand, altered gastrointestinal motility and/or secretions are able to affect glucose and lipid homeostasis in the short and long term. Finally, diabetes has been linked with increased cancer risk at different levels of the GI tract. The presence of GI symptoms and a comprehensive assessment of GI function should be carefully considered in the management of diabetic patients to avoid further complications and to ameliorate the quality of life. Additionally, the presence of gastrointestinal dysfunction should be adequately managed to improve metabolic homeostasis, the efficacy of antidiabetic treatments and secondary prevention strategies.

Protective Effect of Tangshen Formula () on Interstitial Cells of Cajal in Colon of Diabetic Rats

OBJECTIVE

To explore the effect of Tangshen Formula (, TSF), a Chinese herbal medicine, on interstitial cells of Cajal (ICC) in the colon of diabetic rats.

METHODS

Fifty-four male Wistar rats were randomly divided into normal control (NC, n=14) and high-fat diet (HFD) groups (n=40). After 6 weeks, the rats in the HFD group were injected intraperitoneally streptozotocin once (30 mg/kg). Thirty rats with fasting blood glucose higher than 11.7 mmol/L were randomly divided into diabetes (DM) and TSF groups, 15 rats in each group. Rats in the NC and DM groups were intragastrically administered with saline, and those in the TSF group were given with TSF (2.4 g/kg) once daily for 20 weeks. Expression levels of Bax, Bcl-2, and caspase-3 in colonic smooth muscle layer were measured by Western blotting and immunohistochemical staining. The number of ICC was determined by immunohistochemical staining. Immunofluorescence was used for analyzing the ratio of classically activated macrophages (M1) and alternatively activated macrophages (M2) to total macrophages. Electron microscopy was used to observe the epithelial ultrastructure and junctions.

RESULTS

TSF appeared to partially prevented loss of ICC in DM rats (P<0.05). Compared with the NC group, expression levels of Bcl-2, Bax, caspase-3, and TNF-α as well as the ratio of M1 to total macrophages increased in DM rats (all P<0.05), and the ratio of M2 to total macrophages decreased (P<0.05 or P<0.01). Compared with the DM group, TSF decreased the expression levels of abovementioned proteins and restore M2 to total macrophages ratio (P<0.05 or P<0.01). TSF appeared to attenuate the ultrastructural changes of epithelia and improve the tight and desmosome junctions between epithelia reduced in the DM rats.

CONCLUSION

Reduced number of ICC in DM rats may be associated with damage of the intestinal barrier. The protective effects of TSF on ICC may be through repair of the epithelial junctions, which attenuates inflammation and inflammation-initiated apoptosis in colon of DM rats.

Electroacupuncture accelerates the delayed intestinal transit in POI by suppressing M1 like muscularis macrophages and IL6 secretion

BACKGROUND

Electroacupuncture (EA) at ST-36 could accelerate the delayed gastrointestinal (GI) motility in many GI motility dysfunction models, but the definite effect and mechanisms are unclear. In this study, we intended to investigate the effects of EA on intestinal manipulation (IM) mice model and involved mechanisms.

METHODS

Male C57BL/6 mice were randomized into five groups: normal control, intestinal manipulation (IM), IM with sham EA (SEA), IM with high-frequency EA (HEA), and IM with low-frequency EA (LEA). The GI transit was evaluated. The infiltration of muscularis macrophages (MMφ) and its phenotype were analyzed with flow cytometry. Magnetic-activated cell sorting was applied to isolate MMφ, and the relationship between the MMφ and interstitial cells of Cajal (ICCs) was further investigated.

RESULTS

(1) Compared with the IM group, HEA and LEA attenuated the delayed intestinal transit. (2) Both the HEA and LEA obviously reduced the MMφ and suppressed the M1 activation of the MMφ in the ileum. (3) EA restored the disrupted ICC networks through inhibiting the release of IL6 by the MMφ.

CONCLUSION

(1) Electroacupuncture at acupoint ST-36 could accelerate the delayed intestinal transit in the IM murine model by restoring the ICC networks. (2) EA protected the ICCs through reducing the MMφ, inhibiting its M1 polarization and its IL6 secretion.

Helicobacter pylori causes delayed gastric emptying by decreasing interstitial cells of Cajal

Helicobacter pylori (HP) infection is one of the most frequent bacterial infections in humans and is associated with the pathogenesis of gastric motility disorders such as delayed gastric emptying (DGE). Although HP infection is considered to delay gastric emptying, there has been little research on the underlying mechanism. Gastric motility involves interactions among gastrointestinal hormones, smooth muscle, enteric and extrinsic autonomic nerves and interstitial cells of Cajal (ICCs), and ICCs play an important role in gastrointestinal motility. Mutation or loss of stem cell factor (SCF) expression is known to reduce the number of ICCs or alter the integrity of the ICC network, contributing to gastrointestinal dysmotility. The aim of the present study was to investigate whether a reduction in ICCs contributes to the DGE caused by HP. A mouse model of HP infection was established and gastric emptying was compared between HP-infected and uninfected mice using the bead method. In addition, ICC counts and SCF expression levels in gastric tissue were evaluated using immunohistochemistry and western blotting, respectively. The results revealed that gastric emptying was significantly slower, the number of ICCs in gastric tissue was significantly reduced and the protein level of SCF in gastric tissue was significantly decreased in HP-infected mice compared with uninfected mice. Therefore, it may be concluded that HP reduced the number of ICCs by decreasing the expression of SCF protein in gastric tissue, thereby causing DGE.

Gastric Electrical Pacing Reduces Apoptosis of Interstitial Cells of Cajal via Antioxidative Stress Effect Attributing to Phenotypic Polarization of M2 Macrophages in Diabetic Rats

BACKGROUND

Gastric electrical pacing (GEP) could restore interstitial cells of Cajal in diabetic rats. M2 macrophages contribute to the repair of interstitial cells of Cajal injury though secreting heme oxygenase-1 (HO-1). The aim of the study is to investigate the effects and mechanisms of gastric electrical pacing on M2 macrophages in diabetic models.

METHODS

Sixty male Sprague-Dawley rats were randomized into control, diabetic (DM), diabetic with the sham GEP (DM+SGEP), diabetic with GEP1 (5.5 cpm, 100 ms, 4 mA) (DM+GEP1), diabetic with GEP2 (5.5 cpm, 300 ms, 4 mA) (DM+GEP2), and diabetic with GEP3 (5.5 cpm, 550 ms, 4 mA) (DM+GEP3) groups. The apoptosis of interstitial cells of Cajal and the expression of macrophages were detected by immunofluorescence technique. The expression levels of the Nrf2/HO-1 and NF-κB pathway were evaluated using western blot analysis or immunohistochemical method. Malonaldehyde, superoxide dismutase, and reactive oxygen species were tested to reflect the level of oxidative stress.

RESULTS

Apoptosis of interstitial cells of Cajal was increased in the DM group but significantly decreased in the DM+GEP groups. The total number of macrophages was almost the same in each group. In the DM group, M1 macrophages were increased and M2 macrophages were decreased. However, M2 macrophages were dramatically increased and M1 macrophages were reduced in the DM+GEP groups. Gastric electrical pacing improved the Nrf2/HO-1 pathway and downregulated the phosphorylation of NF-κB. In the DM group, the levels of malonaldehyde and reactive oxygen species were elevated and superoxide dismutase was lowered, while gastric electrical pacing reduced the levels of malonaldehyde and reactive oxygen species and improved superoxide dismutase.

CONCLUSION

Gastric electrical pacing reduces apoptosis of interstitial cells of Cajal though promoting M2 macrophages polarization to play an antioxidative stress effect in diabetic rats, which associates with the activated Nrf2/HO-1 pathway and the phosphorylation of NF-κB pathway.

Intestinal proinflammatory macrophages induce a phenotypic switch in interstitial cells of Cajal

Interstitial cells of Cajal (ICCs) are pacemaker cells in the intestine, and their function can be compromised by loss of C-KIT expression. Macrophage activation has been identified in intestine affected by Hirschsprung disease-associated enterocolitis (HAEC). In this study, we examined proinflammatory macrophage activation and explored the mechanisms by which it downregulates C-KIT expression in ICCs in colon affected by HAEC. We found that macrophage activation and TNF-α production were dramatically increased in the proximal dilated colon of HAEC patients and 3-week-old Ednrb-/- mice. Moreover, ICCs lost their C-KIT+ phenotype in the dilated colon, resulting in damaged pacemaker function and intestinal dysmotility. However, macrophage depletion or TNF-α neutralization led to recovery of ICC phenotype and restored their pacemaker function. In isolated ICCs, TNF-α-mediated phosphorylation of p65 induced overexpression of microRNA-221 (miR-221), resulting in suppression of C-KIT expression and pacemaker currents. We also identified a TNF-α/NF-κB/miR-221 pathway that downregulated C-KIT expression in ICCs in the colon affected by HAEC. These findings suggest the important roles of proinflammatory macrophage activation in a phenotypic switch of ICCs, representing a promising therapeutic target for HAEC.

Plasma endocannabinoids and cannabimimetic fatty acid derivatives are altered in gastroparesis: A sex- and subtype-dependent observation

BACKGROUND

Gastroparesis (GP) is a motility disorder of the stomach presenting with upper gastrointestinal symptoms in the setting of delayed gastric emptying. Endocannabinoids are involved in the regulation of GI function including motility. However, their role in the pathophysiology of GP has not been sufficiently investigated. Our goal was to compare the circulating levels of endocannabinoids and cannabimimetic fatty acid derivatives in GP versus control subjects.

METHODS

The study compared plasma concentrations of endocannabinoids and their lipoamine and 2-acyl glycerol congeners, measured by high-pressure liquid chromatography/tandem mass spectrometry (HPLC-MS-MS), in adult patients with diabetic gastroparesis (DM-GP; n = 24; n = 16 female), idiopathic gastroparesis (ID-GP; n = 19; n = 11 female), diabetic patients without GP (DM; n = 19; n = 10 female), and healthy controls (HC; n = 18; n = 10 female). Data, presented as mean ± SEM, were analyzed with ANOVA (Sidak post hoc).

KEY RESULTS

Endocannabinoids anandamide (AEA: 0.5 ± 0.1 nMol/L) and 2-arachidonoyl glycerol (2-AG: 2.6 ± 0.7 nMol/L) were significantly lower in female DM-GP patients vs. DM females (AEA: 2.5 ± 0.7 nMol/L and 2-AG: 9.4 ± 3.3 nMol/L). Other monoacylglycerols including 2-palmitoyl glycerol and 2-oleoyl glycerol were also lower in female DM-GP patients compared to DM females. No changes were observed in men.

CONCLUSIONS & INFERENCES

Endocannabinoids and other fatty acid derivatives with cannabimimetic properties are reduced in female DM-GP patients. Since GP, particularly with diabetic etiology, is more prevalent among women and since cannabinoids are antiemetic, this decrease in levels may contribute to symptom development in these subjects. Targeting the endocannabinoid system may be a future therapeutic option in DM-GP patients.

Gastrointestinal autonomic neuropathy in diabetes

Gastrointestinal autonomic neuropathy represents an important and diverse, but poorly appreciated, manifestation of diabetic autonomic neuropathy that impacts negatively on quality of life. There is no test to assess gastrointestinal autonomic nerve damage directly in humans; cardiovascular autonomic reflex tests are often used as a surrogate, but are suboptimal. Gastrointestinal symptoms are common in diabetes, but usually correlate only weakly with disordered motility. Diabetic gastroparesis, or abnormally delayed gastric emptying, occurs frequently and is the best characterized manifestation of gastrointestinal autonomic neuropathy. There is a bi-directional relationship between postprandial glycaemia and the rate of gastric emptying. However, autonomic neuropathy can affect the function of any gut segment from the esophagus to the anus. Current management options for gastrointestinal autonomic neuropathy are, for the main part, empirical and sub-optimal.

Study on the Mechanisms of Banxia Xiexin Decoction in Treating Diabetic Gastroparesis Based on Network Pharmacology

In China, Banxia Xiexin decoction (BXD) is applied to treat diabetic gastroparesis (DGP), but its key active ingredients and mechanisms against DGP are unclear. This study is designated to reveal the molecular mechanisms of BXD in treating DGP by adopting a creative approach known as network pharmacology to explore the active ingredients and therapeutic targets of BXD. In our study, 730 differentially expressed genes of DGP were obtained, and 30 potential targets of BXD against DGP were screened out (including ADRB2, DRD1, FOS, MMP9, FOSL1, FOSL2, JUN, MAP2, DRD2, MYC, F3, CDKN1A, IL6, NFKBIA, ICAM1, CCL2, SELE, DUOX2, MGAM, THBD, SERPINE1, ALOX5, CXCL11, CXCL2, CXCL10, RUNX2, CD40LG, C1QB, MCL1, and ADCYAP1). Based on the findings, BXD contains 60 compounds with therapeutic effect on DGP, including the key active ingredients such as quercetin, wogonin, baicalein, beta-sitosterol, and kaempferol. Sixty-eight pathways including TNF signaling pathway, IL-17 signaling pathway, and AGE-RAGE signaling pathway were significantly enriched. In this study, the mechanisms of BXD in treating DGP are affirmed to be a complex network with multi-target and multi-pathway, which provides a reference for future experimental studies.

Autonomic function in gastroparesis and chronic unexplained nausea and vomiting: Relationship with etiology, gastric emptying, and symptom severity

BACKGROUND

Autonomic 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.

METHODS

We 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 RESULTS

Low 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].

CONCLUSIONS

Autonomic 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.

INFERENCES

Gastroparesis 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.

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.

Transcriptome profiling reveals significant changes in the gastric muscularis externa with obesity that partially overlap those that occur with idiopathic gastroparesis

Background

Gastric emptying is impaired in patients with gastroparesis whereas it is either unchanged or accelerated in obese individuals. The goal of the current study was to identify changes in gene expression in the stomach muscularis that may be contributing to altered gastric motility in idiopathic gastroparesis and obesity.

Methods

Quantitative real time RT-PCR and whole transcriptome sequencing were used to compare the transcriptomes of lean individuals, obese individuals and either lean or obese individuals with idiopathic gastroparesis.

Results

Obesity leads to an increase in mRNAs associated with muscle contractility whereas idiopathic gastroparesis leads to a decrease in mRNAs associated with PDGF BB signaling. Both obesity and idiopathic gastroparesis were also associated with similar alterations in pathways associated with inflammation.

Conclusions

Our findings show that obesity and idiopathic gastroparesis result in overlapping but distinct changes in the gastric muscularis transcriptome. Increased expression of mRNAs encoding smooth muscle contractile proteins may be contributing to the increased gastric motility observed in obese subjects, whereas decreased PDGF BB signaling may be contributing to the impaired motility seen in subjects with idiopathic gastroparesis.

Electronic supplementary material

The online version of this article (10.1186/s12920-019-0550-3) contains supplementary material, which is available to authorized users.

X-ray evaluation of intestinal dysmotility induced by Eimeria pragensis infection in C57BL/6 mice

This study was conducted to elucidate the intestinal dysmotility during coccidiosis. C57BL/6 male mice at seven weeks of age were inoculated with Eimeria pragensis sporulated oocysts (100 to 1,000 oocysts). The intestinal motility was evaluated by observing discharging time of barium sulfate (Ba₂SO₄) after oral administration (WITT: the whole intestinal transit time). The exact location of the dysmotility was analyzed by intermittent barium gastrography. Upper intestinal dysmotility was evaluated by charcoal propulsion study. Additionally, the occurrence of dysmotility was observed at different post-infection times (4, 7, and 14 days post-infection (d.p.i.)) and in infection-dose dependent manner (100, 300, and 1,000 oocysts). As the E. pragensis infected mice had significantly lower feed intake compared to the control group, we designed a feed apprehension study to evaluate the effect of low feed intake on the intestinal dysmotility. The WITT of infected mice at 7 d.p.i. was significantly longer (6 hr) than the uninfected mice (2.5 hr). Intestinal dysmotility was observed in the small intestine, caecum, and colorectum in the infected mice. Charcoal propulsion was slower in infected group (reaching to 40.4% of the whole small intestine) compared to control group (68.0%). The dysmotility was observed at the beginning of the patent period (7 d.p.i.) and subsided as the patency ended (14 d.p.i.). Mice with lower feed intake appeared to have similar intestinal motility as control mice. In summary, this study revealed the evidence of intestinal hypomotility during E. pragensis infection.

Is gastroparesis a gastric disease?

BACKGROUND

Gastroparesis is a digestive syndrome characterized by delayed gastric emptying (GE) and by symptoms that are suggestive of gastroduodenal motor disorders. There are three grades of gastroparesis of increasing severity: (a) mild gastroparesis; (b) compensated gastroparesis; and (c) gastric failure. GE abnormalities are partially related to symptom type and severity, and other mechanisms may be involved.

AIM

To investigate enteric dysmotility (ED) in patients with suspected gastroparesis.

METHODS

Patients with symptoms suggestive of gastroparesis were consecutively included in the study and underwent a ¹³ C-octanoic acid GE breath test and small bowel manometry (SBM). Clinical features were recorded using predefined, validated questionnaires at entry.

KEY RESULTS

The study enrolled 88 patients (71 women; mean age: 37.8 ± 14.3 years). Gastric emptying was delayed in 25 patients (28.4%), and 70 patients (79.5%) presented small bowel motor abnormalities including bursts, abnormal activity fronts, inability to respond to meal ingestion, and hypocontractility. Gastric emptying was delayed in 24 of the 70 patients with ED (34.3% vs 5.5% of patients with normal SBM). Enteric dysmotility was detected in 24 of 25 patients (96%) with delayed GE. Patients with and without delayed GE showed similar moderate/severe gastroparesis manifestations, but patients with ED significantly more often had moderate/severe gastroparesis manifestations than patients with normal SBM (grade 1:14% vs 39%, grade 2:62% vs 56%, grade 3:24% vs 5%, respectively).

CONCLUSIONS AND INFERENCES

Enteric dysmotility was more frequent than delayed GE in patients with symptoms suggestive of gastroparesis. Gastroparesis severity was associated with small bowel motor abnormalities but not with delayed GE.

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.

Diabetic Gastroparesis and Nondiabetic Gastroparesis

Gastroparesis can be divided into diabetic and nondiabetic, and the 3 main causes of gastroparesis are diabetic, postsurgical, and idiopathic. Delayed gastric emptying is the main manifestation of motility disorders for gastroparesis. Symptoms of gastroparesis are nonspecific and severity can vary. Nausea and vomiting are more common in diabetic gastroparesis whereas abdominal pain and early satiety are more frequent in idiopathic gastroparesis. Medication is still the mainstay of treatment of gastroparesis; however, the development of gastric electric stimulation and gastric peroral endoscopic pyloromyotomy brings more options for the treatment of diabetic and nondiabetic gastroparesis.

Diabetic gastroparesis: current challenges and future prospects

Diabetic gastroparesis (DMGP) is a condition of delayed gastric emptying after gastric outlet obstruction has been excluded. Symptoms of nausea, vomiting, early satiety, bloating, and abdominal pain are associated with DMGP. Uncontrolled symptoms can lead to overall poor quality of life and financial burdens on the healthcare system. A combination of antiemetics and prokinetics is used in symptom control; metoclopramide is the main prokinetic available for clinical use and is the only U.S. Food and Drug Administration-approved agent in the United States. However, a black box warning in 2009 reporting its association with tardive dyskinesia and recommending caution in chronically using this agent beyond 3 months has decreased its role in clinical practice. There is an unmet need for new prokinetics with good efficacy and safety profiles. Currently, there are several new drugs with different mechanisms of action in the pipeline that are under investigation and show promising preliminary results. Surgically combining gastric electrical stimulation with pyloroplasty is considered "gold" standard. Advances in therapeutic endoscopic intervention with gastric per-oral endoscopic pyloromyotomy have also been shown to improve gastric emptying and gastroparesis (GP) symptoms. In this review, we will comment on the challenges encountered when managing patients with DMGP and provide an update on advances in drug development and endoscopic and surgical interventions.

Analysis of the Relationship between Helicobacter pylori Infection and Diabetic Gastroparesis

Background:

Whether Helicobacter pylori infection is associated with diabetic gastroparesis (DGP) is unclear. This study aimed to investigate the potential correlation between H. pylori infection and DGP.

Methods:

In this study, 163 patients with type 2 diabetes mellitus and 175 nondiabetic patients who were treated in our department were divided into DGP, simple diabetes, non-DGP (NDG), and normal groups based on their conditions. The H. pylori infection rate in each group was calculated. H. pylori eradication therapy was performed for patients with H. pylori infection in each group. The eradication rates were compared between the groups, and the improvements in gastroparesis-associated symptoms were compared before and after treatment in patients with DGP.

Results:

The H. pylori infection rate was 74.6% in the DGP group, which was significantly higher than that in the simple diabetes (51.1%, P < 0.01), NDG (57.7%, P < 0.05), and normal groups (48.0%, P < 0.01). With increased disease course, the incidence of DGP and the H. pylori infection rate gradually increased (P < 0.05). In the DGP group, the incidences of upper abdominal pain and distention, early satiety, and anorexia were 75.5%, 66.0%, and 67.9%, respectively, before eradication treatment; and 43.4%, 35.8%, and 39.6%, respectively, after eradication treatment, and the difference was statistically significant (P < 0.01). In patients with DGP with successful H. pylori eradication, the number of barium strips discharged after eradication was 5.9 ± 1.0, which was significantly larger than that before treatment (4.1 ± 0.7, P < 0.01). In addition, the number of barium strips discharged was significantly larger in patients with DGP with successful H. pylori eradication than those with failed H. pylori eradication (P < 0.01).

Conclusions:

DGP development might be associated with H. pylori infection. H. pylori eradication can effectively improve dyspepsia-associated symptoms and delayed gastric emptying in patients with DGP.

Diabetic Gastroparesis: Principles and Current Trends in Management

This article is a comprehensive review of diabetic gastroparesis, defined as delayed or disordered gastric emptying, including basic principles and current trends in management. This review includes sections on anatomy and physiology, diagnosis and differential diagnosis as well as management and current guidelines for treatment of diabetic gastroparesis. Diabetic gastroparesis (DGp) is a component of autonomic neuropathy resulting from long-standing poorly controlled type 1 and type 2 diabetes. The diagnostic workup of DGp first excludes obstruction and other causes including medications that may mimic delayed/disordered gastric emptying. Targeting nutrition, hydration, symptomatic relief and glycemic control are mainstays of treatment for DGp. Additionally, optimal treatment of DGp includes good glycemic management, often involving customizing insulin delivery using basal-bolus insulin and technology, including sensor-augmented pumps and continuous glucose monitoring systems. Prokinetic medications may be helpful in DGp symptoms, although only limited number of medications is currently available in the USA. Selected medication-refractory patients with DGp may benefit from gastric neuromodulation, and some from surgical interventions including pyloric therapies that can also be done endoscopically. As is true of any of the diabetic complications, prevention of DGp by early and optimal glycemic control is more cost-effective.Funding: Hansa Medcell, India.

Muscularis macrophage development in the absence of an enteric nervous system

The nervous system of the bowel regulates the inflammatory phenotype of tissue resident muscularis macrophages (MM), and in adult mice, enteric neurons are the main local source of colony stimulating factor 1 (CSF1), a protein required for MM survival. Surprisingly, we find that during development MM colonize the bowel before enteric neurons. This calls into question the requirement for neuron-derived CSF1 for MM colonization of the bowel. To determine if intestinal innervation is required for MM development, we analyzed MM of neonatal Ret^-/- (Ret KO) mice that have no enteric nervous system in small bowel or colon. We found normal numbers of well-patterned MM in Ret KO bowel. Similarly, the abundance and distribution of MM in aganglionic human colon obtained from Hirschsprung disease patients was normal. We also identify endothelial cells and interstitial cells of Cajal as the main sources of CSF1 in the developing bowel. Additionally, MM from neonatal Ret KOs do not differ from controls in baseline activation status or cytokine-production in response to lipopolysaccharide. Unexpectedly, these data demonstrate that the enteric nervous system is dispensable for MM colonization and patterning in the bowel, and suggest that modulatory interactions between MM and the bowel nervous system are established postnatally.

Idiopathic gastroparesis is associated with specific transcriptional changes in the gastric muscularis externa

BACKGROUND

The molecular changes that occur in the stomach that are associated with idiopathic gastroparesis are poorly described. The aim of this study was to use quantitative analysis of mRNA expression to identify changes in mRNAs encoding proteins required for the normal motility functions of the stomach.

METHODS

Full-thickness stomach biopsy samples were collected from non-diabetic control subjects who exhibited no symptoms of gastroparesis and from patients with idiopathic gastroparesis. mRNA was isolated from the muscularis externa and mRNA expression levels were determined by quantitative reverse transcriptase (RT)-PCR.

KEY RESULTS

Smooth muscle tissue from idiopathic gastroparesis patients had decreased expression of mRNAs encoding several contractile proteins, such as MYH11 and MYLK1. Conversely, there was no significant change in mRNAs characteristic of interstitial cells of Cajal (ICCs) such as KIT or ANO1. There was also a significant decrease in mRNA-encoding platelet-derived growth factor receptor α (PDGFRα) and its ligand PDGFB and in Heme oxygenase 1 in idiopathic gastroparesis subjects. In contrast, there was a small increase in mRNA characteristic of neurons. Although there was not an overall change in KIT expression in gastroparesis patients, KIT expression showed a significant correlation with gastric emptying whereas changes in MYLK1, ANO1 and PDGFRα showed weak correlations to the fullness/satiety subscore of patient assessment of upper gastrointestinal disorder-symptom severity index scores.

CONCLUSIONS AND INFERENCES

Our findings suggest that idiopathic gastroparesis is associated with altered smooth muscle cell contractile protein expression and loss of PDGFRα⁺ cells without a significant change in ICCs.

Muscularis macrophages: Key players in intestinal homeostasis and disease

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Muscularis macrophages densily colonize the outermost layer of the gastrointestinal tract.

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Muscularis macrophages communicate with enteric neurons in a bidirectional matter.

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Muscularis macrophages are tissue-protective but can contribute to disease.

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Current challenges are to decipher therapeutic potentials of muscularis macrophages.

Macrophages residing in the muscularis externa of the gastrointestinal tract are highly specialized cells that are essential for tissue homeostasis during steady-state conditions as well as during disease. They are characterized by their unique protective functional phenotype that is undoubtedly a consequence of the reciprocal interaction with their environment, including the enteric nervous system. This muscularis macrophage-neuron interaction dictates intestinal motility and promotes tissue-protection during injury and infection, but can also contribute to tissue damage in gastrointestinal disorders such as post-operative ileus and gastroparesis. Although the importance of muscularis macrophages is clearly recognized, different aspects of these cells remain largely unexplored such their origin, longevity and instructive signals that determine their function and phenotype. In this review, we will discuss the phenotype, functions and origin of muscularis macrophages during steady-state and disease conditions. We will highlight the bidirectional crosstalk with neurons and potential therapeutic strategies that target and manipulate muscularis macrophages to restore their protective signature as a treatment for disease.

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.

Tumor necrosis factor alpha derived from classically activated "M1" macrophages reduces interstitial cell of Cajal numbers

BACKGROUND

Delayed gastric emptying in diabetic mice and humans is associated with changes in macrophage phenotype and loss of interstitial cells of Cajal (ICC) in the gastric muscle layers. In diabetic mice, classically activated M1 macrophages are associated with delayed gastric emptying, whereas alternatively activated M2 macrophages are associated with normal gastric emptying. This study aimed to determine if secreted factors from M1 macrophages could injure mouse ICC in primary culture.

METHODS

Cultures of gastric ICC were treated with conditioned medium (CM) from activated bone marrow-derived macrophages (BMDMs) and the effect of CM was quantified by counting ICC per high-powered field.

KEY RESULTS

Bone marrow-derived macrophages were activated to a M1 or M2 phenotype confirmed by qRT-PCR. Conditioned medium from M1 macrophages reduced ICC numbers by 41.1%, whereas M2-CM had no effect as compared to unconditioned, control media. Immunoblot analysis of 40 chemokines/cytokines found 12 that were significantly increased in M1-CM, including tumor necrosis factor alpha (TNF-α). ELISA detected 0.697±0.03 ng mL^-1 TNF-α in M1-CM. Recombinant mouse TNF-α reduced Kit expression and ICC numbers in a concentration-dependent manner (EC50 = 0.817 ng mL^-1 ). Blocking M1-CM TNF-α with a neutralizing antibody preserved ICC numbers. The caspase inhibitor Z-VAD.fmk partly preserved ICC numbers (cells/field; 6.63±1.04, 9.82±1.80 w/Z-VAD.fmk, n=6, P<.05).

CONCLUSIONS & INFERENCES

This work demonstrates that TNF-α secreted from M1 macrophages can result in Kit loss and directly injure ICC in vitro partly through caspase-dependent apoptosis and may play an important role in ICC depletion in diabetic gastroparesis.

Ionized calcium-binding adaptor molecule 1 positive macrophages and HO-1 up-regulation in intestinal muscularis resident macrophages

Small intestinal muscularis externa macrophages have been associated with interstitial cells of Cajal. They have been proposed to play various roles in motility disorders and to take part in a microbiota‐driven regulation of gastrointestinal motility. Our objective was to understand the reaction of resident macrophages of the musculature to a pro‐inflammatory stimulator, lipopolysaccharide (LPS). Mice were injected with LPS or saline and sacrificed after 6 hr. Whole mounts were stained with antibodies toward CD169, ionized calcium‐binding adaptor molecule 1 (iba1) (microglial/macrophage marker) and heme oxygenase‐1 (HO‐1). Cell densities were measured using unbiased stereology. Results: iba1^pos cells showed an overall higher density than CD169^pos and HO‐1^pos cells. Most HO‐1^pos and iba1^pos cells were positive for CD 169 in serosa and at Auerbach's plexus (AP). At the deep muscular plexus, mainly iba1^pos cells were present, and were mostly CD169^neg; a few HO‐1^pos cells were present. Conclusions: A new subset of resident macrophages in the intestinal muscularis externa was discovered, identified as iba1^pos CD169^neg. HO‐1 is constitutively present in most macrophages in serosa and at AP, suggesting a M2 phenotype. LPS‐treatment results in an up‐regulation of HO‐1^pos/CD169^neg cells in serosa and at AP. Anat Rec, 300:1114–1122, 2017. © 2016 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists

Investigational drug therapies for the treatment of gastroparesis

INTRODUCTION

Gastroparesis is defined by nausea, vomiting, pain, early satiety and bloating, and characterized by delayed gastric emptying without obvious structural abnormalities. Metoclopramide is widely used, increasing gastric emptying and inhibiting nausea and vomiting. Other drugs are available in certain countries and some are used 'off-label' because they increase gastric emptying or inhibit emesis. However, correlation between gastroparesis symptoms and rates of gastric emptying is poor. For anti-emetic drugs, dose-ranging and Phase III trials in gastroparesis are lacking. Areas covered: Gastric motility may still be disordered, leading to nausea, even though gastric emptying is unchanged. One hypothesis is that interstitial cells of Cajal (ICC) are damaged by diabetes leading to gastric dysrhythmia and nausea. Novel approaches to treatment of nausea also include the use of ghrelin receptor agonists, highlighting a link between appetite and nausea. Expert opinion: There is an urgent need to diversify away from historical drug targets. In particular, there is a need to control nausea by regulating ICC functions and/or by facilitating appetite via ghrelin receptor agonists. It is also important to note that different upper gastrointestinal disorders (gastroparesis, chronic unexplained nausea and vomiting, functional dyspepsia) are difficult to distinguish apart, suggesting wider therapeutic opportunity.

Measures of Autonomic Dysfunction in Diabetic and Idiopathic Gastroparesis

Background

Gastroparesis is a condition classically characterized by delayed gastric emptying and is associated with considerable morbidity. While the etiology of gastroparesis remains elusive, autonomic dysfunction may play an important role, especially as many patients with gastroparesis also have diabetes. The aim of this study was to determine whether measures of autonomic function differ between adults with diabetic gastroparesis (DG) and adults with idiopathic gastroparesis (IG).

Methods

Tests of systemic autonomic function were performed among 20 adults with GD (six men and 14 women, mean age: 42 years) and 21 adults with IG (seven men and 14 women, mean age: 37 years). Measures included vagal cholinergics by R-R interval percentage variation (RRI-PV) and sympathetic adrenergics by vasoconstriction to cold (VC) and postural adjustment ratio (PAR). The two groups were compared using Wilcoxon rank sum tests and linear regression analysis (STATA 10.0).

Results

In univariate analysis, the following autonomic measures differed significantly between DG and IG: VC (P = 0.004), PAR (P = 0.045), VC + PAR (P = 0.002) and RRI-PV (P < 0.001). In multivariate analysis (P = 0.002, R² = 0.55), only RRI-PV (adjusted odds ratio (aOR): 1.02, 95% confidence interval (CI): 1.01 - 1.03) differed significantly between DG and IG patients.

Conclusions

Vagal cholinergics are affected to a greater degree in DG compared to IG, suggesting that impaired vagal tone is not a universal mechanism for gastroparesis.

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.

Disorders of gastrointestinal hypomotility

Ingestion and digestion of food as well as expulsion of residual material from our gastrointestinal tract requires normal propulsive, i.e. motor, function. Hypomotility refers to inherited or acquired changes that come with decreased contractile forces or slower transit. It not only often causes symptoms but also may compromise nutritional status or lead to other complications. While severe forms, such as pseudo-obstruction or ileus, may have a tremendous functional impact, the less severe forms of hypomotility may well be more relevant, as they contribute to common disorders, such as functional dyspepsia, gastroparesis, chronic constipation, and irritable bowel syndrome (IBS). Clinical testing can identify changes in contractile activity, defined by lower amplitudes or abnormal patterns, and the related effects on transit. However, such biomarkers show a limited correlation with overall symptom severity as experienced by patients. Similarly, targeting hypomotility with pharmacological interventions often alters gut motor function but does not consistently improve symptoms. Novel diagnostic approaches may change this apparent paradox and enable us to obtain more comprehensive information by integrating data on electrical activity, mechanical forces, patterns, wall stiffness, and motions with information of the flow of luminal contents. New drugs with more selective effects or more specific delivery may improve benefits and limit adverse effects. Lastly, the complex regulation of gastrointestinal motility involves the brain-gut axis as a reciprocal pathway for afferent and efferent signaling. Considering the role of visceral input in emotion and the effects of emotion on visceral activity, understanding and managing hypomotility disorders requires an integrative approach based on the mind-body continuum or biopsychosocial model of diseases.

Emerging strategies for the treatment of gastroparesis

Gastroparesis is a syndrome of delayed gastric emptying in the absence of mechanical obstruction. Symptoms can be debilitating, affect nutritional states, and significantly impact patients' quality of life. The management of these patients can prove quite difficult to many providers. This article will review the current management recommendations of gastroparesis, discuss investigational medications and interventions, and summarize future directions of therapies targeting the underlying disease process. Current therapies are subdivided into those improving gastric motility and those directly targeting symptoms. Non-pharmacologic interventions, including gastric stimulator implantation and intra-pyloric botulinum toxic injection are reviewed. A discussion of expert opinion in the field, a look into the future of gastroparesis management, and a key point summary conclude the article.

Intrinsic Gastrointestinal Macrophages: Their Phenotype and Role in Gastrointestinal Motility

There is an increasing awareness of the role of macrophages in the regulation and maintenance of gastrointestinal function in health and disease. This work has proceeded in the context of an increased understanding of the complex phenotypic variation in macrophages throughout the body and has revealed previously un-identified roles for macrophages in diseases like gastroparesis, post-operative ileus and inflammatory bowel disease. Opportunities for exploiting the phenotypic modulation of tissue resident macrophages have been identified as possible therapies for some of these diseases. In addition, macrophages are an established component of the innate immune system that can respond to variations and changes in the intestinal microbiome and potentially mediate part of the impact of the microbiota on intestinal health. We reviewed the latest work on novel concepts in defining macrophage phenotype, discuss possible mechanisms of action for tissue-resident macrophages in the gut, address the significance of microbiome effects on macrophage phenotype and review the known and possible roles of macrophages in motility disorders of the gastrointestinal tract.

Effectiveness and safety of Helicobacter pylori eradication in treating diabetic gastroparesis patients with Helicobacter pylori infection: Meta-analysis

AIM: To evaluate the effectiveness and safety of Helicobacter pylori (H. pylori) eradication in treating diabetic gastroparesis (DGP) patients with H. pylori infection.

METHODS: Online databases (PubMed, EMbase, Cochrane Library, Wangfang, CNKI and CBMdice) were searched for randomized controlled trials investigating therapeutic effects of H. pylori eradication vs conventional treatment. Outcomes were analyzed with RevMan 5.3.

RESULTS: Six randomized controlled trials containing 508 patients were included. The results of meta-analysis showed that H. pylori eradication was superior to conventional treatment for DGP patients in clinical effects (RR = 1.33, 95%CI: 1.21-1.47, P < 0.00001). The incidence of adverse events was similar between the two therapies (P = 0.39).

CONCLUSION: Compared with the conventional treatment, H. pylori eradication has more significant clinical effects and comparable incidence of adverse events.

Current advances in treatment of gastroparesis

INTRODUCTION

Gastroparesis is a syndrome defined by delayed gastric emptying in the absence of mechanical obstruction. Gastroparesis has significant symptomatology and negative impacts on the patient's quality of life.

AREAS COVERED

This article reviews current treatment options for gastroparesis, recent advances in treatment and future directions that treatment may head. Current options are broadly divided into prokinetics and symptom modulators. Within each group, current modalities as well as recent advances are discussed according to agent mechanism of action. Lastly, findings regarding the cellular pathophysiology involved in gastroparesis will be briefly reviewed along with their implications for future treatments.

EXPERT OPINION

The numerous motor functions and neural inputs that control gastric motility are complex and not fully understood. Our lack of understanding of its pathophysiology has led to treatment options which are empirical, palliative and often ineffective. Newly intensified interest in the cellular pathophysiology behind gastroparesis provides promise for a new era of treatments. Identification of common cellular changes in gastroparesis has provided targets for treatment that may allow us to one day better treat the symptoms of gastroparesis related to its underlying pathophysiology. This is the future of gastroparesis therapy.