Gastrointestinal Motility Research Articles

The effect of calabash chalk on the gastrointestinal motility and transit time of male albino Wistar rat

The effect of calabash chalk on the gastrointestinal motility and transit time of male albino Wistar rat

A Comprehensive Review and Update on Cannabis Hyperemesis Syndrome

Cannabis, derived from Cannabis sativa plants, is a prevalent illicit substance in the United States, containing over 400 chemicals, including 100 cannabinoids, each affecting the body’s organs differently upon ingestion. Cannabis hyperemesis syndrome (CHS) is a gut–brain axis disorder characterized by recurring nausea and vomiting intensified by excessive cannabis consumption. CHS often goes undiagnosed due to inconsistent criteria, subjective symptoms, and similarity to cyclical vomiting syndrome (CVS). Understanding the endocannabinoid system (ECS) and its dual response (pro-emetic at higher doses and anti-emetic at lower doses) is crucial in the pathophysiology of CHS. Recent research noted that type 1 cannabinoid receptors in the intestinal nerve plexus exhibit an inhibitory effect on gastrointestinal motility. At the same time, the thermoregulatory function of endocannabinoids might explain compulsive hot bathing in CHS patients. The prevalence of cannabis CHS is expected to rise as legal restrictions on its recreational use decrease in several states. Education and awareness are vital in diagnosing and treating CHS as its prevalence increases. This comprehensive review explores the ECS’s involvement, CHS management approaches, and knowledge gaps to enhance understanding of this syndrome.

The mechanism of transcutaneous gastric pacing treatment on gastrointestinal motility recovery and inflammation improvement in early-stage acute pancreatitis patients.

Acute pancreatitis (AP) is often accompanied by gastrointestinal motility disorders. The purpose of this study was to investigate the efficacy and possible mechanism of transcutaneous gastric pacing (TGP) in early-stage AP patients. Sixty-five AP patients were randomly divided into conventional treatment group and TGP group. The serum ghrelin and vasoactive intestinal peptide (VIP) were used to assess the possible gastrointestinal hormonal mechanism involved. The parameters of electrogastrogram (EGG) were used to evaluate the gastric motility in AP patients. The first defecation time was used to assess the recovery of intestinal motility. The heart rate variability (HRV) test was performed to assess autonomic nervous function. Compared with the conventional treatment group, the TGP treatment significantly improved symptoms in early AP patients, and shortened the first defecation time (p < 0.05) and the hospital days (p < 0.05). The level of VIP (P < 0.05) was also decreased in TGP group. The percentage of normal gastric slow waves (GSWS) (p < 0.05) was increased. The interleukin (IL)-6 level was decreased (P < 0.05). Concurrently, the vagal activity (HF) was increased (p < 0.01), the sympathetic activity (LF) was decreased (p < 0.01), and the ratio of sympathetic vagal (LF/HF) was decreased (p < 0.01). The TGP treatment significantly improves the clinical symptoms in early AP patients. It also increases the percentage of normal GSWS. The therapeutic effect of TGP may be caused by autonomic nervous function mechanisms.

Case report: Complications after using the “blind-stitch” method in a dairy cow with a left displaced abomasum: treatment, outcome, and economic evaluation

A fourth lactation dairy cow that was 35 days in milk was referred to the clinic for treatment after undergoing unsuccessful treatment of a left displaced abomasum (LDA). The physical examination revealed complications after using the “blind-stitch” method for correction of the LDA; the cow had an abnormal general demeanor, decreased gastrointestinal motility, and local inflammation of the abdominal wall at the site of the suture. Systemic antibiotics, anti-inflammatory drugs, and intravenous fluids were administered, and a right flank laparotomy and omentopexy according to Dirksen were performed after cutting the suture and breaking down the adhesions of the localized peritonitis between the abdominal wall and the abomasal puncture site. The cow was monitored clinically and discharged 2 weeks after referral. The cow was milked for another two lactations producing a total of 18,000 kg of milk, with a lifetime production of 59,141 kg. The total cost for the case was 310 € for the first intervention using the “blind-stitch” method and 897 € for the second laparotomic intervention. The costs (excluding tax) of both procedures including physical examination, surgery, medications, diagnostics, and labor were calculated. The lost revenue associated with the withdrawal period and lower milk production was 4,168 €. Percutaneous LDA fixation techniques, such as the “blind-stitch” and “toggle-pin” methods, have gained popularity because they are quick and cost-effective and involve minimal labor. However, many buiatricians are critical of these techniques because of the high risk of complications. The following four factors require careful consideration when choosing a method for LDA correction: (1) Percutaneous methods require precision and adherence to the described inclusion, exclusion, and cancelation criteria; (2) Operator skill is essential, and therefore regularly performing laparotomies increases surgical experience and enables the veterinarian to better manage different and more complex abdominal disorders; (3) By performing a laparotomy, other underlying abdominal disorders such as reticuloperitonitis and abomasal ulcers may be detected; (4) Postoperative husbandry and treatment are important factors affecting the outcome. The cost calculated for this case underlines the potential benefit and necessity of successful animal health management and the importance of a highly skilled veterinarian and farm workforce.

Methodological advances in gastrointestinal tract physiology measurements: relevance to nutritional studies.

The gastrointestinal (GI) tract plays a critical role in nutrition and the pathophysiology of disease, and there is an increasing variety of methodologies available for the assessment of various aspects of GI physiology. Advancements in assessment methods, including techniques to study gut motility, fermentation, permeability, and microbiota composition, have provided researchers with powerful tools to investigate the impact of diet on GI tract physiology and the microbiota-gut-brain axis. Mechanistic evidence from reverse translational studies, which apply findings from human studies to preclinical models in a "bedside-to-bench" approach, have also enhanced our understanding of the bidirectional interactions and candidate signalling molecules among the diet-gut-brain relationship. Interpreting data from these advanced techniques and study designs requires a thorough understanding of their principles, applications, and limitations. This review aims to summarise the methodological advances in GI tract physiology measurements and their application in nutritional studies, focusing on gut motility, fermentation, and permeability. We will present examples of how these techniques have been utilised in recent research, discuss their advantages and limitations, and provide insights on their use and interpretation in research. Understanding the capabilities and limitations of these tools is crucial for designing robust studies and elucidating the complex interplay between diet and the GI tract. The scope of this review encompasses recent advancements in GI tract assessment methodologies and their implications for nutritional research, providing a comprehensive overview for researchers in the field.

Iota-Carrageenan from Marine Alga Solieria filiformis Prevents Naproxen-Induced Gastrointestinal Injury via Its Antioxidant and Anti-Inflammatory Activities

Background: Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in therapy due to their anti-inflammatory and analgesic properties. However, their clinical use is often associated with gastrointestinal complications. Thus, this study aimed to investigate the protective effect of a sulfated iota-carrageenan isolated from the marine alga Solieria filiformis (IC-Sf) against naproxen-induced gastrointestinal injury. Methods: Parameters of gastrointestinal injury, secretory and motor functions, and toxicity were evaluated. Results: The results demonstrated that IC-Sf significantly reduced naproxen-induced gastrointestinal macroscopic injury, with a maximum effect observed at 30 mg/kg. IC-Sf also preserved gastrointestinal antioxidant defense and prevented lipid peroxidation, with a reduction in the non-protein sulfhydryl group (NP-SH) and malondialdehyde (MDA) concentrations induced by naproxen. Additionally, IC-Sf mitigated naproxen-induced gastrointestinal inflammation, as evidenced by reduced myeloperoxidase (MPO) activity, tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1β). IC-Sf did not alter gastric secretion or gastrointestinal motility. In addition, the animals treated with IC-Sf did not present toxic effects. Conclusions: In conclusion, IC-Sf protected the gastrointestinal tract against the harmful effects of naproxen by inhibiting the inflammatory response and lipid peroxidation, suggesting its potential as a new therapeutic agent or food additive.

Electrointestinography, ultrasonographic contractility, and borborygmi of the cecum and colon are not altered by a single episode of hand walking exercise in healthy horses.

To evaluate the effect of hand walking exercise on myoelectrical activity and contractility in normal, healthy horses. Prospective experimental design. A convenience sample of 8 horses were randomized to a control or hand walking treatment group; each horse underwent both treatments. After a 30-minute baseline electrointestinography (EIG), horses were stall rested or hand walked for 15 minutes. Electrointestinography was repeated immediately and at 2 hours. Ultrasonography and auscultation monitored cecal and left ventral colon (LVC) contractions during EIG. Electrointestinography spectral analysis obtained dominant frequency (DF), dominant power (DP), total power (TP) frequency distribution, and changes in slow-wave rhythmic activity. The median (IQR) DF in cycles per minute (cpm) was higher for the cecum (2.067 cpm; IQR, 0.633 cpm) compared to the LVC (2.0 cpm; IQR, 0.396 cpm) but was unchanged by either treatment. Cecal DP (0.0086 mV; IQR, 0.0070 mV) was higher than LVC DP (0.0068 mV; IQR, 0.0051 mV) in the hand walking group, but DP and TP were unaffected by either treatment over time. Borborygmi at all time points were unchanged in both treatment groups. Ultrasonographic contractions were similar across time in both treatment groups and correlated with borborygmi (ρ = 0.63). Dominant power did not correlate with contractions or borborygmi (P > .2081). Brief hand walking as a single strategy to increase gastrointestinal motility did not affect contractility or EIG in normal horses. Fasting and stall rest may not represent the spectrum of severity of gastrointestinal stasis observed in clinical cases. This model is directly applicable to horses fasted prior to surgical procedures.

Obesogenic Cafeteria Diet Induces Dynamic Changes in Gut Microbiota, Reduces Myenteric Neuron Excitability, and Impairs Gut Contraction in Mice.

The cafeteria diet (CAF) is a superior diet model in animal experiments compared to the conventional high-fat diet (HFD), effectively inducing obesity, metabolic disturbances and multi-organ damage. Nevertheless, its impact on gut microbiota composition during the progression of obesity, along with its repercussions on the enteric nervous system (ENS) and gastrointestinal motility has not been completely elucidated. To gain more insight into the effects of CAF diet in the gut, C57BL/6 mice were fed with CAF or standard diet for 2 or 8 weeks. CAF-fed mice experienced weight gain, disturbed glucose metabolism, dysregulated expression of colonic IL-6, IL-22, TNFα and TPH1, and altered colon morphology, starting at week 2. Fecal DNA was isolated and gut microbiota composition was monitored by sequencing the V3-V4 16S rRNA region. Sequence analysis revealed that Clostridia and Proteobacteria were specific biomarkers associated with CAF-feeding at week 2, while Bacteroides, Actinobacteria were prominent at week 8. Additionally, the impact of CAF diet on ENS was investigated (week 8), where HuC/D+ neurons were measured and counted, and their biophysical properties were evaluated by patch-clamp. Gut contractility was tested in whole-mount preparations. Myenteric neurons in CAF-fed mice exhibited reduced body size, incremented cell density and decreased excitability. The amplitude and frequency of the rhythmic spontaneous contractions in colon and ileum were affected by the CAF diet. Our findings demonstrate, for the first time, that CAF diet gradually changes the gut microbiota and promotes low-grade inflammation, impacting the functional properties of myenteric neurons and gut contractility in mice.

Effect of bariatric surgery on the pharmacokinetics of drugs used for attention-deficit hyperactivity disorder-A case series.

Changes in gastrointestinal physiology following bariatric surgery may affect the pharmacokinetics of drugs. Data on the impact of bariatric surgery on drugs used for attention-deficit/hyperactivity disorder (ADHD) are limited. In patients treated with ADHD medication and undergoing bariatric surgery, serial drug concentrations were measured for 24 h preoperatively and one, six and 12months postoperatively. Primary outcome was change in area under the concentration-time curve from 0 to 24 h (AUC0-24), with other pharmacokinetic variables as secondary outcomes. Eight patients treated with lisdexamphetamine (n= 4), dexamphetamine (n= 1), methylphenidate (n= 1) and atomoxetine (n= 2) were included. In total, 409 samples were analysed. Patients underwent sleeve gastrectomy (n= 5) and Roux-en-Y gastric bypass (n= 3). AUC0-24 and Cmax of dexamphetamine increased after surgery in those using the prodrug lisdexamphetamine. There was no clear-cut reduction in tmax postoperatively. For ritalinic acid and atomoxetine, no changes in AUC0-24 were observed, but for atomoxetine, a higher Cmax and a shorter tmax were observed postoperatively. Bariatric surgery may increase the systemic exposure of dexamphetamine after intake of lisdexamphetamine. Patients using lisdexamphetamine should be followed with regard to adverse drug reactions after bariatric surgery, and, if available, therapeutic drug monitoring should be considered.

Fermented Gold Kiwi Improves Gastrointestinal Motility and Functional Constipation: An Animal Study and Human Randomized Clinical Test.

Constipation is a functional disorder of the gastrointestinal system characterized by difficult bowel movements, infrequent defecation, reduced water content, and hard stools. This study aims to evaluate the preventive effects of fermented gold kiwis (FGK) on loperamide-induced constipation in rats and investigate its efficacy in improving constipation symptoms in human patients through a randomized clinical trial. In the animal study, FGK was administered orally at doses of 50, 125, and 250 mg/kg to constipated rats for two weeks, resulting in significant improvements in constipation parameters. FGK increased serum serotonin and acetylcholine levels and suppressed increases in serum dopamine concentration. FGK also upregulated mRNA expression of the serotonin-synthesizing receptors 5-HT3R and 5-HT4R and suppressed the expression of the dopamine 2-receptor (D2R) in the duodenum. Furthermore, FGK inhibited inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. In the clinical trials, the improvement in constipation symptoms was evaluated using the gastrointestinal symptom rating scale (GSRS). Clinical trial participants reported significant improvements in constipation symptoms after receiving FGK. These findings suggest that FGK effectively relieves constipation in both animals and humans, indicating its potential as an effective dietary supplement.

Pharmaceutical availability testing − can a drug-specific test be relevant for assessing the quality of dietary supplements?

Our current novel analytical approach focuses on testing the quality of dietary supplements. Specifically, we examine the release of substances such as proline, tryptophan, tyrosine, carnitine, and vitamin C sourced from the EU, Switzerland, and the USA.In tablet-form supplements, release levels were low in both pharmacopoeial dissolution tests (Trp5 – 23%; Trp6 – 12%; VitC4 – 23%) and those simulating biorelevant conditions (Trp5 – 53%; Trp6 – 24%; VitC4 – 68%). The implementation of biorelevant conditions PhysioCell for capsule-form supplements led to an enhanced release of substances (from 11 to 106 percentage points) compared to pharmacopoeial dissolution tests. This indicates that the release of their active substance is strongly influenced by gastrointestinal motility, which, due to its high intra- and inter-individual variability, will result in inconsistent and unpredictable release and biological response.Thus, pharmacopeial methods serves as a reliable screening approach for the quality of dietary supplements.

Symposium Review: The Impact of Fatty Acids as Bioactive Nutrients on the Development of Offspring

Fatty acids (FA) are normally considered a source of energy; however, some FA are essential nutrients with different biological functions such as ligands to membrane and nuclear receptors, and upon binding they modify cell function and transcript expression. The bioactive effects of the FA depend on the FA type and family (i.e., n-6 vs n-3). The FA effects on developmental programming have been studied in cattle and sheep with some similarities in the outcomes between species. Feeding n-3 FA during late gestation improves offspring production performance (i.e., milk yield in dairy cows and growth in beef cattle and sheep) compared with the offspring of dams supplemented with mono- and unsaturated FA or with offspring of dams with no FA supplementation. Also, there is a sexual dimorphism in the outcomes of n-3 FA supplementation, where the increase in growth due to n-3 FA seems to be more evident in males; but it might decrease growth in females. There are multiple assumptions as to how this physiological process occurs. Based on published literature, the developmental effect does not appear to be due to changes in hypothalamic regulations of dry matter intake and energy expenditure or liver and adipose tissue functions. The changes in offspring growth can be attributed to changes in gastrointestinal tract physiology, changes in immune response, or both, probably due to epigenetic changes in those tissues. Feeding n-3 FA in late gestation to the pregnant dam increases expression of amino acid transporters (mRNA and protein) in the offspring's duodenum, associated with changes in DNA methylation. Regarding immune function, the increase in offspring performance has been associated with decreased haptoglobin after weaning in calves or increases in lipid mediators, such as resolvin-D1 at birth. Omega-3 supplementation during late gestation affects offspring growth; changes in the offspring's gut and immune system biology can explain the sexual dysmorphism observed in changed body weight; however, we are unaware which of these basic mechanisms is responsible for the observed changes in biology.

Recovery of gastrointestinal functional after surgery for abdominal tumors: A narrative review.

Postoperative gastrointestinal dysfunction, including temporary nonmechanical suppression of gastrointestinal motility (known as postoperative ileus), occurs in about 10% surgeries of abdominal tumors. Since these complications can prolong hospitalization and affect eating, it is important to understand their risk factors and identify effective interventions to manage or prevent them. The present review comprehensively examined the relevant literature to describe risk factors for postoperative ileus and effective interventions. Risk factors include old age, open surgery, difficulty of surgery, surgery lasting longer than 3 hours, preoperative bowel treatment, infection, and blood transfusion. Factors that protect against postoperative ileus include early enteral nutrition, minimally invasive surgery, and multimodal pain treatment. Interventions that can shorten or prevent such ileus include minimally invasive surgery, early enteral nutrition as well as use of chewing gum, laxatives, and alvimopan. Most of these interventions have been integrated into current guidelines for enhanced recovery of gastrointestinal function after surgery. Future high-quality research is needed in order to clarify our understanding of efficacy and safety.

Modified Double-Tract Reconstruction in Gastrointestinal Reconstruction after Proximal Gastrectomy.

To determine the clinical efficacy and safety of modified double-channel anastomosis for digestive tract reconstruction in proximal gastrectomy for early gastric cancer (EGC). Case series. Place and Duration of the Study: Department of Gastrointestinal Surgery, Heji Hospital, Changzhi Medical College, Shanxi, China, from January to November 2022. Based on inclusion and exclusion criteria, this study included a total of 21 patients with oesophagogastric junction cancer or proximal gastric cancer who underwent laparoscopic proximal gastrectomy with modified double-channel anastomosis. After resection of the proximal stomach, the remaining stomach was shaped into a tube. The distal end of the oesophagus was anastomosed to the jejunum. The jejunum was anastomosed 10-15 cm from the oesophagojejunostomy site laterally to the anterior wall of the stomach 3 cm from the gastric remnant. General data including operative time, anastomosis time, intraoperative blood loss, time to oral intake, length of hospital stay, and postoperative complications were evaluated. Postoperative gastroscopy and gastrointestinal imaging were performed to assess the residual stomach motility and anti-reflux effect. All twenty-one patients underwent modified double-channel anastomosis. The mean operation time was 254 (211 - 297) minutes. Mean reconstruction time was 65 (60 - 70) minutes. A mean of 19 (15 - 29) lymph nodes were cleared. Mean intraoperative blood loss was 86 (78.5-105ml). Mean time to oral intake was 6 (5 - 6.5) days. Postoperatively, there were two cases of pulmonary infection. There was no occurrence of anastomotic stenosis, anastomotic bleeding, or leakage. Gastrointestinal contrast study at 6 months postoperatively revealed reduced gastrointestinal motility in three cases and good residual gastric motility observed in the remaining patients. Gastroscopic examination at 6 months postoperatively revealed only one case of reflux oesophagitis. Modified double-channel anastomosis for proximal gastrectomy is safe and feasible. It provides a good anti-reflux effect and gastric emptying function without increasing the risk of postoperative complications. Adenocarcinoma of the oesophagogastric junction, Upper gastric carcinoma, Proximal gastrectomy, Double-tract reconstruction.

Modified Double-Tract Reconstruction in Gastrointestinal Reconstruction after Proximal Gastrectomy.

To determine the clinical efficacy and safety of modified double-channel anastomosis for digestive tract reconstruction in proximal gastrectomy for early gastric cancer (EGC). Case series. Place and Duration of the Study: Department of Gastrointestinal Surgery, Heji Hospital, Changzhi Medical College, Shanxi, China, from January to November 2022. Based on inclusion and exclusion criteria, this study included a total of 21 patients with oesophagogastric junction cancer or proximal gastric cancer who underwent laparoscopic proximal gastrectomy with modified double-channel anastomosis. After resection of the proximal stomach, the remaining stomach was shaped into a tube. The distal end of the oesophagus was anastomosed to the jejunum. The jejunum was anastomosed 10-15 cm from the oesophagojejunostomy site laterally to the anterior wall of the stomach 3 cm from the gastric remnant. General data including operative time, anastomosis time, intraoperative blood loss, time to oral intake, length of hospital stay, and postoperative complications were evaluated. Postoperative gastroscopy and gastrointestinal imaging were performed to assess the residual stomach motility and anti-reflux effect. All twenty-one patients underwent modified double-channel anastomosis. The mean operation time was 254 (211 - 297) minutes. Mean reconstruction time was 65 (60 - 70) minutes. A mean of 19 (15 - 29) lymph nodes were cleared. Mean intraoperative blood loss was 86 (78.5-105ml). Mean time to oral intake was 6 (5 - 6.5) days. Postoperatively, there were two cases of pulmonary infection. There was no occurrence of anastomotic stenosis, anastomotic bleeding, or leakage. Gastrointestinal contrast study at 6 months postoperatively revealed reduced gastrointestinal motility in three cases and good residual gastric motility observed in the remaining patients. Gastroscopic examination at 6 months postoperatively revealed only one case of reflux oesophagitis. Modified double-channel anastomosis for proximal gastrectomy is safe and feasible. It provides a good anti-reflux effect and gastric emptying function without increasing the risk of postoperative complications. Adenocarcinoma of the oesophagogastric junction, Upper gastric carcinoma, Proximal gastrectomy, Double-tract reconstruction.

Theaflavin-3,3′-digallate (TF3) attenuated constipation by promoting gastrointestinal motility and modulating the gut microbiota: A comparative study of TF3 and the anti-constipation drug mosapride in mice

Theaflavin-3,3′-digallate (TF3) attenuated constipation by promoting gastrointestinal motility and modulating the gut microbiota: A comparative study of TF3 and the anti-constipation drug mosapride in mice

Lacticaseibacillus rhamnosus LRJ-1 alleviates constipation through promoting gut Bacteroides-derived γ-aminobutyric acid production

Multiple gastrointestinal disorders are associated with impaired gut microbiota. Probiotic Lacticaseibacillus rhamnosus can improve bowel disorder, however, the action mechanism is poorly understood. We integrated multi-omics data from the gut metagenome, metabolome, and colon transcriptome of constipated mice underlying L. rhamnosus LRJ-1 treatment to provide insights into host-microbial metabolic pathway. We found that oral administration of L. rhamnosus LRJ-1 alleviated constipation in mice accompanied by the increased abundances of fecal γ-aminobutyric acid (GABA) and intestinal commensal Bacteroides, and the activation of host GABAergic synapses. B. uniformis was the most enriched Bacteroides species in constipated mice treated with L. rhamnosus LRJ-1, and contributed to the increased abundance of GABA in the gut. Administration of either B. uniformis ATCC 8492 or GABA alleviated constipation and increased gastrointestinal motility in constipated mice. Knockout of the GABA biosynthetic gad gene in B. uniformis ATCC 8492 decreased GABA production and blocked its beneficial effects on constipation. These results confirm the therapeutic potential of L. rhamnosus LRJ-1 in alleviating constipation through promoting gut commensal Bacteroides-derived GABA production. Targeting the gut microbiome to regulate GABA production may open new insights for efficient constipation treatment.

Phytoecdysteroids: Quantification in Selected Plant Species and Evaluation of Some Effects on Gastric Smooth Muscles.

Phytoecdysteroids (PEs) are naturally occurring steroid compounds, that have recently gained significant attention, due to their diverse biological activities and high therapeutic potential. The aim of the present study was to quantify some PEs including 20-hydroxyecdysterone (20-HE), ponasterone A (PA), and turkesterone (TU) in selected plant foods and Rhaponticum carthamoides extract. Furthermore, the effects of 20-HE, TU, and R. carthamoides extract, were investigated with in vitro methods using isolated smooth muscle tissues. The levels of 20-HE in the analyzed samples exhibited significant differences, with kaniwa seed extract containing the highest amount, followed by spinach leaf extract, quinoa seed extract, and asparagus stem extract. The in vitro analyses suggested that R. carthamoides extract exhibits dose-dependent cytotoxic effects on smooth muscle cells, with low doses promoting contraction and higher doses inducing relaxation. Additionally, the extract demonstrated a significant inhibitory effect on ACh-induced contractions, while 20-HE enhanced the contractile response. The current findings highlighted phytoecdysteroids' potential for modifying gastrointestinal motility.

In Silico Identification of the Laccase-Encoding Gene in the Transcriptome of the Amazon River Prawn Macrobrachium amazonicum (Heller, 1862)

Background: Macrobrachium amazonicum is an opportunistic and omnivorous species that primarily feeds on plant material. Recent studies have shown that Endo-β-1,4-glucanase and Endo-β-1,4-mannanase are expressed in the transcriptome of adult specimens, while juveniles are capable of digesting nutrients from purified cellulose in their diet. In organisms that degrade raw plant material, laccase plays a key role in oxidizing phenolic compounds found in lignin, leading to its depolymerization and increasing access to cellulose and hemicellulose microfibrils. Objective: In this study, we conducted an in silico identification and characterization of the laccase-encoding gene, as this enzyme is linked to lignin biodegradation in herbivorous crustaceans. Methods: We analyzed the transcriptomes of the hepatopancreas from adult M. amazonicum, sequenced using the Illumina HiSeq 2500 platform. Subsequently, bioinformatics analyses were conducted to predict the conserved regions and active sites associated with laccase activity. Results: A complete open reading frame (ORF) of the laccase protein was identified in all datasets, comprising 609 amino acids. The top 40 similarity hits corresponded exclusively to crustaceans such as prawns, crayfish, and crabs (86.3–51.4%), while the highest divergence was observed in relation to fungi, plants, and bacteria. Three conserved domains were detected, along with the complete set of copper-binding centers (T1Cu, T2Cu, and T3Cu). A notable variable residue was methionine, suggesting a reduced redox potential in M. amazonicum laccase. Conclusion: These findings, combined with recent reports on the nutritional requirements of M. amazonicum, contribute to a deeper understanding of the digestive physiology of this species and offer valuable insights into its ability to utilize plant fibers as energy sources.

Conditional deletion of IP3R1 by Islet1-Cre in mice reveals a critical role of IP3R1 in interstitial cells of Cajal in regulating GI motility.

Inositol 1,4,5-trisphosphate receptor type 1 (IP3R1) has been proposed to play a physiological role in regulating gastrointestinal (GI) motility, but the underlying cell-dependent mechanism remains unclear. Here, we utilized cell-specific IP3R1 deletion strategies to address this question in mice. Conditional IP3R1 knockout mice using Wnt1-Cre, Islet1-Cre mice, and smMHC-CreEGFP were generated. Cell lineage tracing was performed to determine where gene deletion occurred in the GI tract. Whole-gut transit assay and isometric tension recording were used to assess GI function in vivo and in vitro. In the mouse GI tract, Islet1-Cre targeted smooth muscle cells (SMCs) and interstitial cells of Cajal (ICCs), but not enteric neurons. IP3R1 deletion by Islet1-Cre (isR1KO) caused a phenotype of intestinal pseudo-obstruction (IPO), evidenced by prolonged whole-gut transit time, enlarged GI tract, abdominal distention, and early lethality. IP3R1 deletion by Islet1-Cre not only reduced the frequency of spontaneous contractions but also decreased the contractile responses to the muscarinic agonist carbachol (CCh) and electrical field stimulation (EFS) in colonic circular muscles. By contrast, smMHC-CreEGFP only targeted SMCs in the mouse GI tract. Although IP3R1 deletion by smMHC-CreEGFP (smR1KO)also reduced the contractile responses to CCh and EFS in colonic circular muscles, the frequency of spontaneous contractions was less affected, and neither global GI abnormalities nor early lethality was found in smR1KO mice. IP3R1 deletion in both ICCs and SMCs but not in SMCs alone causes an IPO phenotype, suggesting that IP3R1 in ICCs plays an essential role in regulating GI motility in vivo.