Versatile Functions of Somatostatin and Somatostatin Receptors in the Gastrointestinal System

The role of central neurotransmitters in appetite regulation of broilers and layers: similarities and differences

The importance of feeding as a vital physiological function, on the one hand, and the spread of complications induced by its disorder in humans and animals, on the other hand, have led to extensive research on its regulatory factors. Unfortunately, despite many studies focused on appetite, only limited experiments have been conducted on avian, and our knowledge of this species is scant. Considering this, the purpose of this review article is to examine the role of central neurotransmitters in regulating food consumption in broilers and layers and highlight the similarities and differences between these two strains. The methodology of this review study includes a comprehensive search of relevant literature on the topic using appropriate keywords in reliable electronic databases. Based on the findings, the central effect of most neurotransmitters on the feeding of broilers and laying chickens was similar, but in some cases, such as dopamine, ghrelin, nitric oxide, and agouti-related peptide, differences were observed. Also, the lack of conducting a study on the role of some neurotransmitters in one of the bird strains made it impossible to make an exact comparison. Finally, it seems that although there are general similarities in appetite regulatory mechanisms in meat and egg-type chickens, the long-term genetic selection appropriate to breeding goals (meat or egg production) has caused differences in the effect of some neurotransmitters. Undoubtedly, conducting future studies while completing the missing links can lead to a comprehensive understanding of this process and its manipulation according to the breeding purposes of chickens.

Octreotide attenuates intestinal barrier damage by maintaining basal autophagy in Caco2 cells

The intestinal mucosal barrier is of great importance for maintaining the stability of the internal environment, which is closely related to the occurrence and development of intestinal inflammation. Octreotide (OCT) has potential applicable clinical value for treating intestinal injury according to previous studies, but the underlying molecular mechanisms have remained elusive. This article is based on a cell model of inflammation induced by lipopolysaccharide (LPS), aiming to explore the effects of OCT in protecting intestinal mucosal barrier function. A Cell Counting Kit‑8 assay was used to determine cell viability and evaluate the effectiveness of OCT. Gene silencing technology was used to reveal the mediated effect of somatostatin receptor 2 (SSTR2). The changes in intestinal permeability were detected through trans‑epithelial electrical resistance and fluorescein isothiocyanate‑dextran 4 experiments, and the alterations in tight junction proteins were detected using immunoblotting and reverse transcription fluorescence‑quantitative PCR technology. Autophagosomes were observed by electron microscopy and the dynamic changes of the autophagy process were characterized by light chain (LC)3‑II/LC3‑I conversion and autophagic flow. The results indicated that SSTR2‑dependent OCT can prevent the decrease in cell activity. After LPS treatment, the permeability of monolayer cells decreased and intercellular tight junctions were disrupted, resulting in a decrease in tight junction protein zona occludens 1 in cells. The level of autophagy‑related protein LC3 was altered to varying degrees at different times. These abnormal changes gradually returned to normal levels after the combined application of LPS and SSTR2‑dependent OCT, confirming the role of OCT in protecting intestinal barrier function. These experimental results suggest that OCT maintains basal autophagy and cell activity mediated by SSTR2 in intestinal epithelial cells, thereby preventing the intestinal barrier dysfunction in inflammation injury.

Managing gastrointestinal manifestations in systemic sclerosis, a mechanistic approach

INTRODUCTION

Systemic sclerosis (SSc) is a connective tissue disease with heterogeneous presentation. Gastrointestinal (GI) complications of SSc are characterized by esophageal reflux, abnormal motility, and microbiome dysbiosis, which impact patient quality of life and mortality. Preventative therapeutics are lacking, with management primarily aimed at symptomatic control.

AREAS COVERED

A broad literature review was conducted through electronic databases and references from key articles. We summarize the physiology of gastric acid production and GI motility to provide context for existing therapies, detail the current understanding of SSc-GI disease, and review GI medications studied in SSc. Finally, we explore new therapeutic options. We propose a management strategy that integrates data on drug efficacy with knowledge of disease pathophysiology, aiming to optimize future therapeutic targets.

EXPERT OPINION

SSc-GI complications remain a challenge for patients, clinicians, and investigators alike. Management presently focuses on treating symptoms and minimizing mucosal damage. Little evidence exists to suggest immunosuppressive therapy halts progression of GI involvement or reverses damage, leaving many unanswered questions about the optimal clinical approach. Further research focused on identifying patients at risk for GI progression, and the underlying mechanism(s) that drive disease will provide opportunities to prevent long-term damage, and significantly improve patient quality of life.

Improvement of functional dyspepsia with Suaeda salsa (L.) Pall via regulating brain-gut peptide and gut microbiota structure

PURPOSE

The traditional Chinese herbal medicine Suaeda salsa (L.) Pall (S. salsa) with a digesting food effect was taken as the research object, and its chemical composition and action mechanism were explored.

METHODS

The chemical constituents of S. salsa were isolated and purified by column chromatography, and their structures were characterized by nuclear magnetic resonance. The food accumulation model in mice was established, and the changes of the aqueous extract of S. salsa in gastric emptying and intestinal propulsion rate, colonic tissue lesions, serum brain-gut peptide hormone, colonic tissue protein expression, and gut microbiota structure were compared.

RESULTS

Ten compounds were isolated from S. salsa named as naringenin (1), hesperetin (2), baicalein (3), luteolin (4), isorhamnetin (5), taxifolin (6), isorhamnetin-3-O-β-D-glucoside (7), luteolin-3'-D-glucuronide (8), luteolin-7-O-β-D-glucuronide (9), and quercetin-3-O-β-D-glucuronide (10), respectively. The aqueous extract of S. salsa can improve the pathological changes of the mice colon and intestinal peristalsis by increasing the rate of gastric emptying and intestinal propulsion. By adjusting the levels of 5-HT, CCK, NT, SS, VIP, GT-17, CHE, MTL, and ghrelin, it can upregulate the levels of c-kit, SCF, and GHRL protein, and restore the imbalanced structure of gut microbiota, further achieve the purpose of treating the syndrome of indigestion. The effect is better with the increase of dose.

CONCLUSION

S. salsa has a certain therapeutic effect on mice with the syndrome of indigestion. From the perspective of "brain-gut-gut microbiota", the mechanism of digestion and accumulation of S. salsa was discussed for the first time, which provided an experimental basis for further exploring the material basis of S. salsa.

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.

From biology to clinical practice: antiproliferative effects of somatostatin analogs in neuroendocrine neoplasms

Somatostatin analogs (SSA), specifically octreotide and lanreotide, have demonstrated antiproliferative effects in patients with neuroendocrine tumors (NET), a group of rare malignancies of diverse origin and presentation. A prominent feature of NET cells is the expression of G protein-coupled receptors called somatostatin receptors (SSTR). Although these SSTR are not uniformly present in NET, they can be instrumental in the diagnosis and treatment of NET. Apart from their application in nuclear imaging and radionuclide therapy, SSA have proven invaluable in the treatment of hormonal syndromes associated with certain NET (antisecretory effects of SSA), but it took more than two decades to convincingly demonstrate the antiproliferative effects of SSA in metastatic NET with the two pivotal studies PROMID and CLARINET. The current review summarizes three decades of SSA treatment and provides an overview of the clinical trial landscape for SSA monotherapy and combination therapy, including clinical implications and quality of life aspects, as well as ongoing fields of research.

Physiological Appetite Regulation and Bariatric Surgery

Obesity remains a common metabolic disorder and a threat to health as it is associated with numerous complications. Lifestyle modifications and caloric restriction can achieve limited weight loss. Bariatric surgery is an effective way of achieving substantial weight loss as well as glycemic control secondary to weight-related type 2 diabetes mellitus. It has been suggested that an anorexigenic gut hormone response following bariatric surgery contributes to weight loss. Understanding the changes in gut hormones and their contribution to weight loss physiology can lead to new therapeutic treatments for weight loss. Two distinct types of neurons in the arcuate hypothalamic nuclei control food intake: proopiomelanocortin neurons activated by the anorexigenic (satiety) hormones and neurons activated by the orexigenic peptides that release neuropeptide Y and agouti-related peptide (hunger centre). The arcuate nucleus of the hypothalamus integrates hormonal inputs from the gut and adipose tissue (the anorexigenic hormones cholecystokinin, polypeptide YY, glucagon-like peptide-1, oxyntomodulin, leptin, and others) and orexigeneic peptides (ghrelin). Replicating the endocrine response to bariatric surgery through pharmacological mimicry holds promise for medical treatment. Obesity has genetic and environmental factors. New advances in genetic testing have identified both monogenic and polygenic obesity-related genes. Understanding the function of genes contributing to obesity will increase insights into the biology of obesity. This review includes the physiology of appetite control, the influence of genetics on obesity, and the changes that occur following bariatric surgery. This has the potential to lead to the development of more subtle, individualised, treatments for obesity.

Somatostatin-SSTR3-GSK3 modulates human T-cell responses by inhibiting OXPHOS

Introduction

Somatostatin (SST) is a peptide hormone primarily synthesized in the digestive and nervous systems. While its impact on the endocrine system is well-established, accumulating evidence suggests a crucial role for SST and its analogues in modulating immune responses. Despite this, the precise mechanism through which SST regulates T cells has remained largely unknown.

Methods

To elucidate the impact of SST on human T cells, we conducted a series of experiments involving cell culture assays, molecular analyses, and metabolic profiling. Human T cells were treated with SST, and various parameters including proliferation, cytokine production, and metabolic activities were assessed. Additionally, we employed pharmacological inhibitors and genetic manipulations to dissect the signaling pathways mediating SST's effects on T cells.

Results

We showed that SST diminishes T-cell proliferation by influencing IL-2 production and T-cell mitochondrial respiration, while having no discernible impact on TCR-induced glycolysis. Our findings also identified that the regulatory influence of SST on T-cell responses and metabolism is contingent on its receptor, SSTR3. Moreover, we demonstrated that SST governs T-cell responses and metabolism by acting through the T-cell metabolic checkpoint GSK3.

Discussion

Our study provides novel insights into the immunoregulatory function of SST in human T cells, highlighting the complex interplay between hormonal signaling and immune regulation. Understanding the molecular mechanisms underlying SST's effects on T cells may offer therapeutic opportunities for manipulating immune responses in various pathological conditions.

The Coding Logic of Interoception

Interoception, the ability to precisely and timely sense internal body signals, is critical for life. The interoceptive system monitors a large variety of mechanical, chemical, hormonal, and pathological cues using specialized organ cells, organ innervating neurons, and brain sensory neurons. It is important for maintaining body homeostasis, providing motivational drives, and regulating autonomic, cognitive, and behavioral functions. However, compared to external sensory systems, our knowledge about how diverse body signals are coded at a system level is quite limited. In this review, we focus on the unique features of interoceptive signals and the organization of the interoceptive system, with the goal of better understanding the coding logic of interoception.

Remission of organ failure in patients with predicted severe acute pancreatitis treated by somatostation, octreotide and cyclooxygenase-2 inhibitors

BACKGROUND

/Objectives: Persistent organ failure (OF) in severe acute pancreatitis (SAP) is caused by activation of cytokine cascades, resulting in inflammatory injury. Anti-inflammation may be helpful in OF remission in early SAP. To assess the efficacy of anti-inflammatory regimens for OF prevention and remission in patients with predicted SAP and display clinical doctors' acceptance of these strategies, we conducted this retrospective study in the real world.

METHODS

Clinical data of patients with predicted SAP from 2010 to 2017 were retrospectively reviewed. Cases were divided into conventional support (C), C+ somatostatin/octreotide (C + S/O), and C + S/O + Cyclooxygenase-2-inhibitors (C + S/O + COX-2-I). The occurrence of SAP, OF, changes of proportion for three strategies, length of hospital stay, meperidine injection, and cytokine levels were compared. The constituent ratios of the three schemes over eight years were evaluated.

RESULTS

A total of 580 cases (C = 124, C + S/O = 290, C + S/O + COX-2-I = 166) were included. The occurrences of SAP in the C + S/O (28.3 %) and C + S/O + COX-2-I (18.1 %) groups were significantly lower than that in C group (60.5 %, P < 0.001), mainly by reducing persistent respiratory failure (P < 0.001) and renal failure (P = 0.002). C + S/O and C + S/O + COX-2-I regimens significantly decreased new onset OF and enhanced OF amelioration within 48 h when compared with C treatment (P < 0.001) in patients with OF score <2 and ≥ 2 on admission, respectively. C + S/O and C + S/O + COX-2-I as compared with C group significantly decrease OF occurrences in a multivariate logistic regression analysis (P < 0.05).

CONCLUSIONS

Somatostatin or its analogs and cyclooxygenase-2 inhibitors are promising for OF prevention and remission in patients with predicted SAP. The acceptance of combined strategies in the real world has increased, and the occurrence of SAP has decreased annually.

Computerized tomography-guided therapeutic percutaneous puncture catheter drainage-combined with somatostatin for severe acute pancreatitis: An analysis of efficacy and safety

BACKGROUND

Severe acute pancreatitis (SAP), a condition with rapid onset, critical condition and unsatisfactory prognosis, poses a certain threat to human health, warranting optimization of relevant treatment plans to improve treatment efficacy.

AIM

To evaluate the efficacy and safety of computerized tomography-guided therapeutic percutaneous puncture catheter drainage (CT-TPPCD) combined with somatostatin (SS) in the treatment of SAP.

METHODS

Forty-two SAP patients admitted to The Second Affiliated Hospital of Fujian Medical University from June 2020 to June 2023 were selected. On the basis of routine treatment, 20 patients received SS therapy (control group) and 22 patients were given CT-TPPCD plus SS intervention (research group). The efficacy, safety (pancreatic fistula, intra-abdominal hemorrhage, sepsis, and organ dysfunction syndrome), abdominal bloating and pain relief time, bowel recovery time, hospital stay, inflammatory indicators (C-reactive protein, interleukin-6, and procalcitonin), and Acute Physiology and Chronic Health Evaluation (APACHE) II score of both groups were evaluated for comparison.

RESULTS

Compared with the control group, the research group had a markedly higher total effective rate, faster abdominal bloating and pain relief and bowel recovery, shorter hospital length of stay, fewer complications, and lower posttreatment inflammatory indices and APACHE-II scores.

CONCLUSION

CT-TPPCD in combination with SS is effective for SAP patients, which can reduce complications, accelerate symptom resolution, inhibit inflammation, and improve patient condition, with promising prospects for clinical promotion.

The Role of Receptor-Ligand Interaction in Somatostatin Signaling Pathways: Implications for Neuroendocrine Tumors

Neuroendocrine tumors (NETs) arise from neuroendocrine cells and manifest in diverse organs. Key players in their regulation are somatostatin and its receptors (SSTR1-SSTR5). Understanding receptor-ligand interactions and signaling pathways is vital for elucidating their role in tumor development and therapeutic potential. This review highlights SSTR characteristics, localization, and expression in tissues, impacting physiological functions. Mechanisms of somatostatin and synthetic analogue binding to SSTRs, their selectivity, and their affinity were analyzed. Upon activation, somatostatin initiates intricate intracellular signaling, involving cAMP, PLC, and MAP kinases and influencing growth, differentiation, survival, and hormone secretion in NETs. This review explores SSTR expression in different tumor types, examining receptor activation effects on cancer cells. SSTRs' significance as therapeutic targets is discussed. Additionally, somatostatin and analogues' role in hormone secretion regulation, tumor growth, and survival is emphasized, presenting relevant therapeutic examples. In conclusion, this review advances the knowledge of receptor-ligand interactions and signaling pathways in somatostatin receptors, with potential for improved neuroendocrine tumor treatments.

Development of Self-Assembled Biomimetic Nanoscale Collagen-like Peptide-Based Scaffolds for Tissue Engineering: An In Silico and Laboratory Study

Development of biocomposite scaffolds has gained tremendous attention due to their potential for tissue regeneration. However, most scaffolds often contain animal-derived collagen that may elicit an immunological response, necessitating the development of new biomaterials. Herein, we developed a new collagen-like peptide,(Pro-Ala-His)10 (PAH)10, and explored its ability to be utilized as a functional biomaterial by incorporating it with a newly synthesized peptide-based self-assembled gel. The gel was prepared by conjugating a pectin derivative, galataric acid, with a pro-angiogenic peptide (LHYQDLLQLQY) and further functionalized with a cortistatin-derived peptide, (Phe-Trp-Lys-Thr)4 (FWKT)4, and the bio-ionic liquid choline acetate. The self-assembly of (PAH)10 and its interactions with the galactarate-peptide conjugates were examined using replica exchange molecular dynamics (REMD) simulations. Results revealed the formation of a multi-layered scaffold, with enhanced stability at higher temperatures. We then synthesized the scaffold and examined its physicochemical properties and its ability to integrate with aortic smooth muscle cells. The scaffold was further utilized as a bioink for bioprinting to form three-dimensional cell-scaffold matrices. Furthermore, the formation of actin filaments and elongated cell morphology was observed. These results indicate that the (PAH)10 hybrid scaffold provides a suitable environment for cell adhesion, proliferation and growth, making it a potentially valuable biomaterial for tissue engineering.

Mucosal distribution of somatostatin-secreting gastric Delta cells in children with gastrointestinal reflux diseases

Introduction

Gastric delta cells (D-cells) secrete somatostatin, which is the primary paracrine suppressor of acid secretion. The number and distribution of D-cells were investigated in children exhibiting endoscopic findings of duodenogastric and gastroesophageal reflux. This study aimed to determine whether the number of D-cells in the gastric body differs from that in the gastric antrum in children using endoscopic findings.

Methods

We retrospectively used immunohistochemical assessments to determine the number of D-cells in the gastric body and antrum in 102 children who presented with abdominal symptoms. The number and distribution of D-cells were investigated according to symptoms, endoscopic findings of gastroesophageal reflux and duodenogastric reflux, and Helicobacter pylori infection status.

Results

The average age of the patients was 13.3 ± 3.3 years, and the male-to-female ratio was 1:1.68. The mean number of D-cells per high-power field in the antrum and body did not significantly differ by symptoms. However, these values were significantly lower in the gastric body than in the antrum for all symptoms (p < 0.05). Children with reflux had a higher mean number of D-cells (9.6 ± 8.8) in the gastric body than did those without reflux (4.3 ± 3.4) (p = 0.007). Furthermore, the number of D-cells in the gastric body was marginally significantly lower in Helicobacter pylori-positive children (4.9 ± 6.5) than in Helicobacter pylori-negative children (8.5 ± 8.2) (p = 0.053).

Conclusion

The number of D-cells in the gastric body decreased in Helicobacter pylori-positive children but significantly increased in children with duodenogastric reflux. Therefore, somatostatin peptide secretion by D-cells may be a major pathophysiological pathway in gastrointestinal reflux disease.

Molecular simulations of SSTR2 dynamics and interaction with ligands

The cyclic peptide hormone somatostatin regulates physiological processes involved in growth and metabolism, through its binding to G-protein coupled somatostatin receptors. The isoform 2 (SSTR2) is of particular relevance for the therapy of neuroendocrine tumours for which different analogues to somatostatin are currently in clinical use. We present an extensive and systematic computational study on the dynamics of SSTR2 in three different states: active agonist-bound, inactive antagonist-bound and apo inactive. We exploited the recent burst of SSTR2 experimental structures to perform μs-long multi-copy molecular dynamics simulations to sample conformational changes of the receptor and rationalize its binding to different ligands (the agonists somatostatin and octreotide, and the antagonist CYN154806). Our findings suggest that the apo form is more flexible compared to the holo ones, and confirm that the extracellular loop 2 closes upon the agonist octreotide but not upon the antagonist CYN154806. Based on interaction fingerprint analyses and free energy calculations, we found that all peptides similarly interact with residues buried into the binding pocket. Conversely, specific patterns of interactions are found with residues located in the external portion of the pocket, at the basis of the extracellular loops, particularly distinguishing the agonists from the antagonist. This study will help in the design of new somatostatin-based compounds for theranostics of neuroendocrine tumours.

Effect of postoperative utilization of somatostatin on clinical outcome after definitive surgery for duodenal fistula

PURPOSE

To evaluate the effect of postoperative utilization of somatostatin after definitive surgery for duodenal fistula (DF) in preventing a recurrence.

METHODS

Patients with definitive surgery for DF between January 2010 and December 2021 were categorized based on the utilization of somatostatin or not after the surgery. Patients in the Somatostatin group were matched to those in the Non-somatostatin group using propensity scores matching (PSM), so as to evaluate the effect of postoperative use of somatostatin by comparing the two groups.

RESULTS

A total of 154 patients were divided into the in the Somatostatin group (84) and the Non-somatostatin group (70). Forty-three patients (27.9%) exhibited a recurrent fistula, with which the postoperative use of somatostatin was not associated (19 [22.6%] in the Somatostatin group and 24 (34.3%) in the Non-somatostatin group; unadjusted OR 0.56; 95% CI 0.28-1.14; P = 0.11). However, the postoperative usage of somatostatin served as a protective factor for developing into high-output recurrent fistula (eight (13.3%) in the Somatostatin group and 15 (25%) in the Non-somatostatin group; adjusted OR 0.39; 95% CI 0.15-0.93; P = 0.04). After PSM, the recurrent fistula occurred in 29.2% subjects (35/120). The postoperative usage of somatostatin was not associated with recurrent fistula (13 in PSM Somatostatin group vs. 22 in PSM Non-somatostatin group; unadjusted OR 0.48; 95% CI 0.21-1.07; P = 0.07), while its postoperative usage decreased the incidence of recurrent high-output fistula (5/60 in the PSM Somatostatin group, compared with 13/60 in the PSM Non-somatostatin group; adjusted OR 0.30; 95% CI 0.09-0.95).

CONCLUSION

Postoperative use of somatostatin could effectively reduce the incidence of recurrent high-output fistula, without association with overall incidence of postoperative recurrent fistula.

Internalization of somatostatin receptors in brain and periphery

Somatostatin (SRIF) is a neuropeptide that acts as an important regulator of both endocrine and exocrine secretion and modulates neurotransmission in the central nervous system (CNS). SRIF also regulates cell proliferation in normal tissues and tumors. The physiological actions of SRIF are mediated by a family of five G protein-coupled receptors, called somatostatin receptor (SST) SST₁, SST₂, SST₃, SST₄, SST₅. These five receptors share similar molecular structure and signaling pathways but they display marked differences in their anatomical distribution, subcellular localization and intracellular trafficking. The SST subtypes are widely distributed in the CNS and peripheral nervous system, in many endocrine glands and tumors, particularly of neuroendocrine origin. In this review, we focus on the agonist-dependent internalization and recycling of the different SST subtypes in vivo in the CNS, peripheral organs and tumors. We also discuss the physiological, pathophysiological and potential therapeutic effects of the intracellular trafficking of SST subtypes.

Gut microbiota composition alteration analysis and functional categorization in children with growth hormone deficiency

OBJECTIVE

To study changes in the composition and functions of the gut microbiota (GM) in children with growth hormone deficiency (GHD) using high-throughput sequencing.

METHODS

Thirty-three children with GHD diagnosed in Longgang District Maternity and Child Health Hospital were included in the disease group and 24 healthy children of the same age comprised the control group. Total DNA was extracted and amplified from stool samples obtained from all subjects. High-throughput sequencing was used to analyze the GM composition and functions.

RESULTS

The GM from the two groups of children showed significant differences in α-diversity (P < 0.05). In comparison with the control group, the abundance of the phylum Bacteroidetes was significantly higher (45.96% vs. 65.71%) while the Firmicutes count was significantly lower (47.09% vs. 25.20%). At the genus level, the abundance of Prevotella in the disease group was significantly higher (3.16% vs. 20.67%) and that of Lachnospiracea incertae sedis, Clostridium XlVa, and Megamonas was lower (6.576% vs. 1.75%; 4.51% vs. 0.80%; 5.08% vs. 2.02%, respectively). GM functions, including those involved in membrane_transport, energy_metabolism, poorly_characterized, metabolism_of_cofactors_and_vitamins, glycan_biosynthesis_and_metabolism, transcription, folding,_sorting,_and_degradation, were significantly altered in the disease group. The abundance of various GM components was correlated with endocrine hormone levels.

CONCLUSION

Significant alterations in the GM are seen in children with growth hormone deficiency, which may affect both energy metabolism and the levels of endocrine hormones, potentially leading to growth restriction.

Knock-in mouse models for studying somatostatin and cholecystokinin expressing cells

BACKGROUND

Somatostatin (SST) and cholecystokinin (CCK) are peptide hormones that regulate the endocrine system, cell proliferation and neurotransmission.

NEW METHOD

We utilized the novel Easi-CRISPR system to generate two knock-in mouse strains with Cre recombinase in SST- and CCK-expressing cells and validated their utility in the developing and adult brain tissues.

RESULTS

The full nomenclature for the newly generated strains are C57BL/6-Sst^{em1(P2A-iCre-T2A-mCherry)Mirn} and C57BL/6-Cck^{em1(iCre-T2A-mCherry-P2A)Mirn}. For the Sst locus, a P2A-iCre-T2A-mCherry cassette was inserted immediately upstream of the stop codon (C terminus fusion). For the Cck locus, iCre-P2A-mCherry-T2A cassette was inserted at the start codon (N terminus fusion). Knock-in mice were generated using the Easi-CRISPR method. Developmental and adult SST and CCK expressions were preserved and showed an appropriate expression pattern in both models, with an active fluorescent tag in both animal lines.

COMPARISON WITH EXISTING METHODS

Knock-in mouse models to study cell types that produce these critically important molecules are limited to date. The knock-in mice we generated can be used as reporters to study development, physiology, or pathophysiology of SST and CCK expressing cells - without interference with native expression of SST and CCK. In addition, they can be used as Cre driver models to conditionally delete floxed genes in SST and CCK expressing cells across various tissues.

CONCLUSIONS

These two mouse models serve as valuable tools for in vitro and in vivo research studies related to SST and CCK biology across the lifespan and across different tissue types.

Neuropeptides in Cancer: Friend and Foe?

Neuropeptides are small regulatory molecules found throughout the body, most notably in the nervous, cardiovascular, and gastrointestinal systems. They serve as neurotransmitters or hormones in the regulation of diverse physiological processes. Cancer cells escape normal growth control mechanisms by altering their expression of growth factors, receptors, or intracellular signals, and neuropeptides have recently been recognized as mitogens in cancer growth and development. Many neuropeptides and their receptors exist in multiple subtypes, coupling with different downstream signaling pathways and playing distinct roles in cancer progression. The consideration of neuropeptide/receptor systems as anticancer targets is already leading to new biological and diagnostic knowledge that has the potential to enhance the understanding and treatment of cancer. In this review, recent discoveries regarding neuropeptides in a wide range of cancers, emphasizing their mechanisms of action, signaling cascades, regulation, and therapeutic potential, are discussed. Current technologies used to manipulate and analyze neuropeptides/receptors are described. Applications of neuropeptide analogs and their receptor inhibitors in translational studies and radio-oncology are rapidly increasing, and the possibility for their integration into therapeutic trials and clinical treatment appears promising.

Somatostatin plus Gastroscopic Administration of Omeprazole for the Treatment of Acute Upper Gastrointestinal Bleeding: An Exploration of a Promising Alternative

Objective

To analyze the efficacy and safety of somatostatin combined with gastroscopic administration of omeprazole in the treatment of acute upper gastrointestinal bleeding.

Methods

Eligible 112 patients with acute upper gastrointestinal bleeding treated in our hospital from May 2019 to July 2020 were randomized at a ratio of 1 : 1 either to the control group (somatostatin) or observation group (somatostatin combined with omeprazole gastroscope administration). The treatment efficacy, the average hemostasis time, rebleeding rate, average length of hospital stay, and the incidence of adverse reactions were compared.

Results

The study group demonstrated significantly higher total effective rate than the control group (96.45% vs. 80.36%, <0.05). The study group demonstrated superior performances compared to the control group with respect to the average hemostasis time ((14.17 ± 2.53 h) vs. (28.84 ± 4.07 h)), rebleeding rate (3.57% vs. 14.28%), and average length of hospital stay ((5.86 ± 1.26 d) vs. (9.74 ± 1.07 d)) (all p < 0.05). The chi-square test revealed a remarkably lower total incidence of adverse reactions in the study group vs. control group which was (4 (7.14%) vs. 12 (21.43%)) (p < 0.05).

Conclusion

The combination of somatostatin and gastroscopic administration of omeprazole might be a promising alternative for the treatment of acute upper gastrointestinal bleeding. It improves the clinical treatment effect and controls the symptoms of patients, with a good safety profile.

Efficacy of Endoscopic Intervention plus Growth Inhibitor and Patient Self-Management in the Treatment of Esophagogastric Variceal Bleeding in Cirrhosis

Objective

To assess the efficacy of endoscopic intervention plus growth inhibitor and patient self-management in the treatment of esophagogastric variceal bleeding.

Methods

Between January 2019 and December 2021, 60 patients with esophagogastric variceal bleeding treated in our hospital were assessed for eligibility and randomly recruited. They were concurrently and randomly assigned at a ratio of 1 : 1 to receive either endoscopic intervention plus growth inhibitor (control group) or endoscopic intervention plus growth inhibitor and patient self-management (observation group). The endpoint is clinical efficacy.

Results

All eligible patients showed a similar time of hemostasis, success rate of hemostasis, rebleeding rate, and disappearance rate of varicose veins (P > 0.05). Endoscopic intervention plus growth inhibitor and patient self-management were associated with a lower incidence of complication (6.67%, including 1 (3.34%) case of ulcer and 1 (3.34%) case of fever) than endoscopic intervention plus growth inhibitor (26.67%, including 3 (10.00%) cases of ulcer, 2 (6.67%) cases of retrosternal pain, and 3 (10.00%) cases of fever) (P < 0.05). Patients in the observation group had significantly higher life satisfaction scores (25.17 ± 4.28 and 23.68 ± 5.17) than those in the control group (22.13 ± 2.24 and 18.12 ± 3.28) (P < 0.05). A decrease in life satisfaction scores was observed at 6 months after treatment, and the patients given patient self-management showed a higher satisfaction (P < 0.05).

Conclusion

Endoscopic intervention plus growth inhibitor and patient self-management yielded remarkable clinical efficacy in the treatment of esophagogastric variceal bleeding as it reduces the incidence of complication and enhances the life satisfaction of patients, and so it is worthy of clinical promotion.

Exploration of Somatostatin Binding Mechanism to Somatostatin Receptor Subtype 4

Somatostatin (also named as growth hormone-inhibiting hormone or somatotropin release-inhibiting factor) is a regulatory peptide important for the proper functioning of the endocrine system, local inflammatory reactions, mood and motor coordination, and behavioral responses to stress. Somatostatin exerts its effects via binding to G-protein-coupled somatostatin receptors of which the fourth subtype (SSTR4) is a particularly important receptor mediating analgesic, anti-inflammatory, and anti-depressant effects without endocrine actions. Thus, SSTR4 agonists are promising drug candidates. Although the knowledge of the atomic resolution-binding modes of SST would be essential for drug development, experimental elucidation of the structures of SSTR4 and its complexes is still awaiting. In the present study, structures of the somatostatin–SSTR4 complex were produced using an unbiased, blind docking approach. Beyond the static structures, the binding mechanism of SST was also elucidated in the explicit water molecular dynamics (MD) calculations, and key binding modes (external, intermediate, and internal) were distinguished. The most important residues on both receptor and SST sides were identified. An energetic comparison of SST binding to SSTR4 and 2 offered a residue-level explanation of receptor subtype selectivity. The calculated structures show good agreement with available experimental results and indicate that somatostatin binding is realized via prerequisite binding modes and an induced fit mechanism. The identified binding modes and the corresponding key residues provide useful information for future drug design targeting SSTR4.

Somatostatin and Its Receptor System in Colorectal Cancer

Somatostatin (SST)/somatotropin release-inhibiting factor (SRIF) is a well-known neuropeptide, widely distributed in the central and peripheral nervous systems, that regulates the endocrine system and affects neurotransmission via interaction with five SST receptors (SST1-5). In the gastrointestinal tract, the main SST-producing cells include intestinal enteroendocrine cells (EECs) restricted to the mucosa, and neurons of the submucosal and myenteric plexuses. The action of the SRIF system is based on the inhibition of endocrine and exocrine secretion, as well as the proliferative responses of target cells. The SST1–5 share common signaling pathways, and are not only widely expressed on normal tissues, but also frequently overexpressed by several tumors, particularly neuroendocrine neoplasms (NENs). Furthermore, the SRIF system represents the only peptide/G protein-coupled receptor (GPCR) system with multiple approved clinical applications for the diagnosis and treatment of several NENs. The role of the SRIF system in the histogenesis of colorectal cancer (CRC) subtypes (e.g., adenocarcinoma and signet ring-cell carcinoma), as well as diagnosis and prognosis of mixed adenoneuroendocrine carcinoma (MANEC) and pure adenocarcinoma, is poorly understood. Moreover, the impact of the SRIF system signaling on CRC cell proliferation and its potential role in the progression of this cancer remains unknown. Therefore, this review summarizes the recent collective knowledge and understanding of the clinical significance of the SRIF system signaling in CRC, aiming to evaluate the potential role of its components in CRC histogenesis, diagnosis, and potential therapy.