Aloe vera gel confers therapeutic effect by reducing pyroptosis in ethanol-induced gastric ulcer rat model: Role of NLRP3/GSDMD signaling pathway.

BACKGROUND: Gastric ulcer (GU) is a common gastrointestinal tract illness. Aloe vera has anti-inflammatory, antioxidant, and healing characteristics. This research sought to explore the therapeutic impact of Aloe vera gel on ethanol-provoked GU in rats and to elucidate the underlying mechanisms involved. METHODS: An ethanol-induced GU rat model was constructed using forty male Wistar rats distributed at random into four groups: control, ulcer, pantoprazole, and Aloe vera. Gross evaluation of the stomach, ulcer index (UI), inhibition index, and gastric pH estimation were analyzed. Gastric malondialdehyde (MDA) and reduced glutathione (GSH) were determined using the spectrophotometric method, and serum gastrin level was measured by an enzyme-linked immunosorbent assay. Gastric nucleotide-binding domain, leucine-rich repeat, and pyrin domain PYD containing protein 3 (NLRP3) and gasdermin D (GSDMD) mRNA expression levels were estimated by quantitative real-time PCR. Finally, the histopathological examination of the glandular part of stomach tissue was done. RESULTS: The ulcer group revealed a significant increase in MDA, gastrin, NLRP3, and GSDMD and a decrease in gastric pH and GSH compared to the control group. Gross investigations of the ulcer group revealed a hemorrhagic lesion in the stomach and an increase in UI. Also, histopathological results for this group showed severe epithelial loss, haemorrhage, inflammatory cell infiltration, and blood vessel congestion. However, Aloe vera treatment improved the gross, biochemical, molecular, and histopathological alterations induced by ethanol when compared to the ulcer group. CONCLUSIONS: Aloe vera exerted antiulcer activities through modulation of oxidant/antioxidant status, anti-secretory properties, and mitigation of pyroptosis.

Effect of aqueous extract of seed of broccoli on inflammatory cytokines and Helicobacter pylori infection: a randomized, double-blind, controlled trial in patients without atrophic gastritis.

The purpose of this study was to investigate the anti-inflammatory effect of an aqueous extract of seed of broccoli (AESB) in Helicobacter pylori (HP)-infected patients without atrophic gastritis. This was a double-centre, randomized, double-blind, controlled study. A total of 110 HP-infected subjects were randomized to receive either AESB or placebo for 2 months. Inflammatory cytokine (IL-8, IFN-γ, TNF-α, CRP, IL-17A, IL-1ß, IL-18), pepsinogen I, II (PG I, PG II), and gastrin-17 (G-17) measurements and 13C-urea breath tests were performed at baseline and at 60 days. At 60 days, there was no significant difference in any of the inflammatory cytokines, pepsinogen or gastrin between the two groups. However, IL-8, IFN-γ, PG I, PG I/PG II ratio (PGR), and G-17 were reduced by 9.02 pg/mL, 5.08 pg/mL, 24.56 ng/mL, 1.75 and 0.3 pmol/L, respectively, in the AESB group compared with baseline (all P < 0.05). The HP eradication rates in the AESB group and placebo group were 11.11 and 3.70% at 60 days, respectively (P > 0.05). No treatment-related adverse events were reported. Thus, AESB may reduce the risk of gastric mucosal lesions and decrease the risk of gastric cancer by relieving inflammatory cytokines. The safety profile of AESB was satisfactory. This study is registered with the Chinese Clinical Trials Registry (Registration No. ChiCTR2100054249).

Vaccine against gastrin, a polyclonal antibody stimulator, decreases pancreatic cancer metastases.

Growth of pancreatic cancer is stimulated by gastrin in both a paracrine and an autocrine fashion. Traditional therapies have not significantly improved survival, and recently pancreatic cancer has been deemed a "cold" tumor due to its poor response to immunotherapy. Strategies to improve survival of pancreatic cancer are desperately needed. In the current investigation, we studied the effects of an anti-gastrin cancer vaccine, polyclonal antibody stimulator (PAS; formerly called G17DT and Gastrimmune), used alone or in combination with a programmed cell death receptor (PD)-1 immune checkpoint antibody on pancreatic cancer growth, metastases, and the tumor microenvironment (TME). Immune-competent female C57BL/6 mice bearing syngeneic orthotopic murine pancreatic cancer treated with PAS had significantly smaller tumors and fewer metastases. Examination of the TME demonstrated decreased fibrosis with fewer M2 and more M1 tumor-associated macrophages. Expression of the E-cadherin gene was significantly increased and expression of the TGFßR2 gene was decreased compared with controls. Mice treated with PAS or the combination of PAS and PD-1 antibody exhibited significantly less tumor expression of phospho-paxillin, the focal adhesion protein ß-catenin, and matrix metalloproteinase-7. This study suggests that inhibition of the cancer-promoting effects of gastrin in pancreatic cancer can decrease metastases by altering the TME and decreasing pathways that activate the epithelial mesenchymal transition. The PAS vaccine appears to change the TME, making it more susceptible to therapy with an immune checkpoint antibody. This novel combination of two immunotherapies may improve survival of pancreatic cancer by decreasing both tumor growth and metastasis formation.NEW & NOTEWORTHY Survival from advanced pancreatic cancer is poor, in part due to dense fibrosis of the tumor microenvironment, increased number of M2-polarized macrophages that promote angiogenesis and invasion, and lack of "target-specific" therapy. Herein, we report that a tumor vaccine that selectively targets gastrin decreases pancreatic cancer growth and metastases. Furthermore, the gastrin vaccine polyclonal antibody stimulator alters the tumor microenvironment rendering it more responsive to immunotherapy with a programmed cell death receptor-1 immune checkpoint antibody.

177Lu-DOTA-coupled minigastrin peptides: promising theranostic agents in neuroendocrine cancers.

Treatment with radionuclide labeled regulatory peptides is a promising tool in the management of patients with inoperable receptor positive neuroendocrine tumors. Peptide receptor lutetium-177 radionuclide therapy currently has gained ample attention due to high specific accumulation of regulatory peptides at tumor cell surface and promising characteristics of ß- and γ-energy photons of lutetium-177 radionuclide. In this study gastrin peptides analogues were labeled with lutetium-177 by subsequent mixing of 177LuCl3 (~ 185 MBq), ammonium acetate buffer of 5 pH, gentistic acid, aqueous solution of gastrin peptide analogues (1 mg/mL) and heating the reaction mixture at 98 °C which resulted in high radiochemical yield (> 96%). Chromatographic analysis was carried out to analyze the radiochemical purity. The shelf life and serum stability results showed the labeled peptides are sufficiently stable up to 4-h. Glomerular filtration rate study results showed moderate filtration through kidneys. The GFR values of 177Lu-MGCL2 and 177Lu-MGCL4 was noted 48 mL/min and 45 mL/min, respectively. Biodistribution and scintigraphy study using rat and rabbit models showed minimal non-target accumulation, moderate uptake by liver and kidneys. The promising radiochemical yield, stability, GFR values and biodistribution results of 177Lu-MGCL2 & 4 indicate, the agents can be tested clinically for PRRT procedures.

177Lu Labeled Cyclic Minigastrin Analogues with Therapeutic Activity in CCK2R Expressing Tumors: Preclinical Evaluation of a Kit Formulation.

Minigastrin (MG) analogues specifically target cholecystokinin-2 receptors (CCK2R) expressed in different tumors and enable targeted radiotherapy of advanced and disseminated disease when radiolabeled with a beta emitter such as 177Lu. Especially truncated MG analogues missing the penta-Glu sequence are associated with low kidney retention and seem therefore most promising for therapeutic use. Based on [d-Glu1,desGlu2-6]MG (MG11) we have designed the two cyclic MG analogues cyclo1,9[γ-d-Glu1,desGlu2-6,d-Lys9]MG (cyclo-MG1) and cyclo1,9[γ-d-Glu1,desGlu2-6,d-Lys9,Nle11]MG (cyclo-MG2). In the present work we have developed and preclinically evaluated a pharmaceutical kit formulation for the labeling with 177Lu of the two DOTA-conjugated cyclic MG analogues. The stability of the kits during storage as well as the stability of the radiolabeled peptides was investigated. A cell line stably transfected with human CCK2R and a control cell line without receptor expression were used for in vitro and in vivo studies with the radioligands prepared from kit formulations. In terms of stability 177Lu-DOTA-cyclo-MG2 showed advantages over 177Lu-DOTA-cyclo-MG1. Still, for both radioligands a high receptor-mediated cell uptake and favorable pharmacokinetic profile combining receptor-specific tumor uptake with low unspecific tissue uptake and low kidney retention were confirmed. Investigating the therapy efficacy and treatment toxicity in xenografted BALB/c nude mice a receptor-specific and comparable therapeutic effect could be demonstrated for both radioligands. A 1.7- to 2.6-fold increase in tumor volume doubling time was observed for receptor-positive tumors in treated versus untreated animals, which was 39-73% higher when compared to receptor-negative tumors. The treatment was connected with transient bone marrow toxicity and minor signs of kidney toxicity. All together the obtained results support further studies for the clinical translation of this new therapeutic approach.

Omeprazole and PGC-formulated heparin binding epidermal growth factor normalizes fasting blood glucose and suppresses insulitis in multiple low dose streptozotocin diabetes model.

PURPOSE: Our objective was to develop novel nanocarriers (protected graft copolymer, PGC) that improve the stability of heparin binding EGF (HBEGF) and gastrin and then to use PGC-formulated HBEGF (PGC-HBEGF) and Omeprazole (+/- PGC-gastrin) for normalizing fasting blood glucose (FBG) and improving islet function in diabetic mice. METHODS: HBEGF, PGC-HBEGF, Omeprazole, Omeprazole + PGC-HBEGF, Omeprazole + PGC-gastrin + PGC-HBEGF and epidermal growth factor (EGF) + gastrin were tested in multiple low dose streptozotocin diabetic mice. RESULTS: Omeprazole + PGC-HBEGF normalized FBG and is better than EGF + gastrin at improving islet function and decreasing insulitis. Groups treated with Omeprazole, Omeprazole + PGC-HBEGF, or EGF + gastrin have significantly improved islet function versus saline control. All animals that received PGC-HBEGF had significantly reduced islet insulitis versus saline control. Non-FBG was lower for Omeprazole + PGC-gastrin + PGC-HBEGF but Omeprazole + PGC-HBEGF alone showed better FBG and glucose tolerance. CONCLUSIONS: Omeprazole + PGC-HBEGF provides a sustained exposure to both EGFRA and gastrin, improves islet function, and decreases insulitis in multiple low dose streptozotocin diabetic mice. Although HBEGF or EGF elevates non-FBG, it facilitates a reduction of insulitis and, in the presence of Omeprazole, provides normalization of FBG at the end of treatment. The study demonstrates Omeprazole and PGC-HBEGF is a viable treatment for diabetes.

A GLP-1/glucagon (GCG)/CCK2 receptors tri-agonist provides new therapy for obesity and diabetes.

BACKGROUND AND PURPOSE: Glucagon-like peptide-1 (GLP-1) and glucagon (GCG) receptor dual agonist have promising therapeutic effects in the treatment of obesity and diabetes. Moreover, GLP-1 and cholecystokinin 2 (CCK2 ) dual agonists have been shown to restore pancreas function and improve glycaemic control in preclinical studies. We describe, for the first time, the beneficial effects of GLP-1/glucagon receptor and GLP-1/CCK2 dual agonists, which can be integrated into one peptide, resulting in significant anti-diabetes and anti-obesity effectiveness. EXPERIMENTAL APPROACH: The in vitro potency of this novel peptide Xenopus (x) GLP-1/GCG/CCK2 tri-agonist (xGLP/GCG/gastrin) against GLP-1, GCG, CCK1 and CCK2 receptors was determined on cells expressing the corresponding receptors by cAMP accumulation or ERK1/2 phosphorylation assays. The in vivo anti-diabetes and anti-obesity effects of this tri-agonist xGLP/GCG/gastrin were studied in both db/db and diet induced obesity (DIO) mice. KEY RESULTS: xGLP/GCG/gastrin was a potent and selective GLP-1, GCG and CCK2 tri-agonist. In DIO mice, the metabolic benefits of xGLP-1/GCG/gastrin, such as reduction of body weight and hepatic lipid contents were significantly better than those of the peptide ZP3022 (GLP-1/CCK-2 dual agonist) and liraglutide. In a short-term study in db/db mice, xGLP/GCG/gastrin treatment had considerable effects, increasing islet numbers, islet areas and insulin content. In a long-term treatment study using db/db mice, xGLP-1/GCG/gastrin showed a significantly and sustained improvement in glucose tolerance and glucose control compared with that of liraglutide, ZP3022, cotadutide (GLP-1/GCG dual agonist) and xGLP/GCG-15. CONCLUSIONS AND IMPLICATIONS: These results demonstrate the therapeutic potential of xGLP-1/GCG/gastrin for the treatment of obesity and diabetes.

Effects of Quadruple Therapy Combined with Probiotics on Helicobacter Pylori-Related Peptic Ulcer.

The present study was designed to observe the effect of quadruple therapy combined with probiotics on Helicobacter pylori-related peptic ulcer. The patients in the control group (n = 90) were given regular quadruple therapy including proton pump inhibitor ilaprazole enteric-coated tablet + two antibiotics amoxicillin dispersible tablet and metronidazole tablet + colloidal bismuth pectin capsule for 2 weeks. Patients in the study group (n = 90) were given abovementioned quadruple therapy combined with probiotics live combined Bifidobacterium, Lactobacillus, and Enterococcus Capsules, oral for 2 weeks. Then Hp clearance rate, recurrence rate, levels of gastrointestinal hormone makers, and advance reactions between two groups were compared. At the 2nd week after the treatment, the Helicobacter pylori clearance rate in the study group (87.79%) was significantly higher than the control group (78.89%), and the total recurrence rate in the study group (6.67%) was significantly lower than the control group (13.33%) (P < 0.05). Serum gastrin and motilin expression were lower, and somatostatin expressions was significantly higher than those in the control group (P < 0.05). There was no significant difference in the total incidence of adverse reactions between the two groups (P > 0.05). In summary, quadruple therapy combined with probiotics in the treatment of Helicobacter pylori-related peptic ulcer can improve the Helicobacter pylori clearance rate, reduce the Helicobacter pylori recurrence rate, and is beneficial to improving the level of gastrointestinal hormones, with certain safety.

The Influence of Different Spacers on Biological Profile of Peptide Radiopharmaceuticals for Diagnosis and Therapy of Human Cancers.

BACKGROUND: Cancer is the leading cause of death worldwide. Early detection can reduce the disadvantageous effects of diseases and the mortality in cancer. Nuclear medicine is a powerful tool that has the ability to diagnose malignancy without harming normal tissues. In recent years, radiolabeled peptides have been investigated as potent agents for cancer detection. Therefore, it is necessary to modify radiopeptides in order to achieve more effective agents. OBJECTIVE: This review describes modifications in the structure of radioconjugates with spacers who have improved the specificity and sensitivity of the peptides that are used in oncologic diagnosis and therapy. METHODS: To improve the biological activity, researchers have conjugated these peptide analogs to different spacers and bifunctional chelators. Many spacers of different kinds, such as hydrocarbon chain, amino acid sequence, and poly (ethyleneglycol) were introduced in order to modify the pharmacokinetic properties of these biomolecules. RESULTS: Different spacers have been applied to develop radiolabeled peptides as potential tracers in nuclear medicine. Spacers with different charge and hydrophilicity affect the characteristics of peptide conjugate. For example, the complex with uncharged and hydrophobic spacers leads to increased liver uptake, while the composition with positively charged spacers results in high kidney retention. Therefore, the pharmacokinetics of radio complexes correlates to the structure and total charge of the conjugates. CONCLUSION: Radio imaging technology has been successfully applied to detect a tumor in the earliest stage. For this purpose, the assessment of useful agents to diagnose the lesion is necessary. Developing peptide radiopharmaceuticals using spacers can improve in vitro and in vivo behavior of radiotracers leading to better noninvasive detection and monitoring of tumor growth.

Diagnostic Value of Serum Gastrin and Epidermal Growth Factor to the Gastric Ulcer Complicated with Upper Gastrointestinal Hemorrhage.

OBJECTIVE:  To explore the predictive value of serum gastrin (GAS), epidermal growth factor (EGF) levels in gastric ulcer complicated with acute upper gastrointestinal bleeding. STUDY DESIGN: A descriptive study. PLACE AND DURATION OF STUDY: Department of Emergency, Beijing Jiangong Hospital, China, from January 2019 to June 2020. METHODOLOGY: One hundred and twenty-five patients with gastric ulcer and acute upper gastrointestinal bleeding were selected as Group A. One hundred and twenty-five patients with gastric ulcer and no upper gastrointestinal bleeding were selected as Group B. Logistic regression analysis was used to analyse the risk factors of gastric ulcer complicated with acute upper gastrointestinal bleeding. The value of serum GAS, EGF in early diagnosis of gastric ulcer with upper gastrointestinal bleeding was evaluated by receiver operating characteristic (ROC) curve. RESULTS: Univariate analysis showed statistically significant differences between Group A and Group B in taking non-steroidal anti-inflammatory drugs (NSAIDs), helicobacter pylori (Hp) infection, serum GAS and EGF (all p <0.001). Logistic regression analysis showed that raised serum GAS and serum EGF were independent risk factors for gastric ulcer and upper gastrointestinal bleeding (both p <0.001). The ROC area of serum EGF to predict gastric ulcer and acute upper gastrointestinal bleeding was 0.810 (95% CI: 0.753-0.867, p <0.001), greater than ROC area of serum GAS. At serum EGF of ≤109.95 pg/mL, had the 84.8%, sensitivity to predict gastric ulcer and acute upper gastrointestinal bleeding with specificity of 68.8%. CONCLUSION: The predictive value of serum GAS and EGF is high for gastric ulcer complicated with acute upper gastrointestinal bleeding; the predictive value of serum EGF is greater than that of serum GAS. Key Words: Gastric ulcer, Acute upper gastrointestinal bleeding, Serum, Gastrin (GAS), Epidermal growth factor (EGF), Logistic regression, Receiver operating characteristic (ROC) curve.

Pharmacological inhibition of mTORC1 increases CCKBR-specific tumor uptake of radiolabeled minigastrin analogue [177Lu]Lu-PP-F11N.

Rationale: A high tumor-to-healthy-tissue uptake ratio of radiolabeled ligands is an essential prerequisite for safe and effective peptide receptor radionuclide therapy (PRRT). In the present study, we searched for novel opportunities to increase tumor-specific uptake of the radiolabeled minigastrin analogue [177Lu]Lu-DOTA-(DGlu)6-Ala-Tyr-Gly-Trp-Nle-Asp-Phe-NH2 ([177Lu]Lu-PP-F11N), that targets the cholecystokinin B receptor (CCKBR) in human cancers. Methods: A kinase inhibitor library screen followed by proliferation and internalization assays were employed to identify compounds which can increase uptake of [177Lu]Lu-PP-F11N in CCKBR-transfected human epidermoid carcinoma A431 cells and natural CCKBR-expressing rat pancreatic acinar AR42J cells. Western blot (WB) analysis verified the inhibition of the signaling pathways and the CCKBR level, whereas the cell-based assay analyzed arrestin recruitment. Biodistribution and SPECT imaging of the A431/CCKBR xenograft mouse model as well as histological analysis of the dissected tumors were used for in vivo validation. Results: Our screen identified the inhibitors of mammalian target of rapamycin complex 1 (mTORC1), which increased cell uptake of [177Lu]Lu-PP-F11N. Pharmacological mTORC1 inhibition by RAD001 and metformin increased internalization of [177Lu]Lu-PP-F11N in A431/CCKBR and in AR42J cells. Analysis of protein lysates from RAD001-treated cells revealed increased levels of CCKBR (2.2-fold) and inhibition of S6 phosphorylation. PP-F11N induced recruitment of ß-arrestin1/2 and ERK1/2 phosphorylation. In A431/CCKBR-tumor bearing nude mice, 3 or 5 days of RAD001 pretreatment significantly enhanced tumor-specific uptake of [177Lu]Lu-PP-F11N (ratio [RAD001/Control] of 1.56 or 1.79, respectively), whereas metformin treatment did not show a significant difference. Quantification of SPECT/CT images confirmed higher uptake of [177Lu]Lu-PP-F11N in RAD001-treated tumors with ratios [RAD001/Control] of average and maximum concentration reaching 3.11 and 3.17, respectively. HE staining and IHC of RAD001-treated tumors showed a significant increase in necrosis (1.4% control vs.10.6% of necrotic area) and the reduction of proliferative (80% control vs. 61% of Ki67 positive cells) and mitotically active cells (1.08% control vs. 0.75% of mitotic figures). No significant difference in the tumor vascularization was observed after five-day RAD001 or metformin treatment. Conclusions: Our data demonstrates, that increased CCKBR protein level by RAD001 pretreatment has the potential to improve tumor uptake of [177Lu]Lu-PP-F11N and provides proof-of-concept for the development of molecular strategies aimed at enhancing the level of the targeted receptor, to increase the efficacy of PRRT and nuclear imaging.

Emerging hormonal-based combination pharmacotherapies for the treatment of metabolic diseases.

Obesity and its comorbidities, such as type 2 diabetes mellitus and cardiovascular disease, constitute growing challenges for public health and economies globally. The available treatment options for these metabolic disorders cannot reverse the disease in most individuals and have not substantially reduced disease prevalence, which underscores the unmet need for more efficacious interventions. Neurobiological resilience to energy homeostatic perturbations, combined with the heterogeneous pathophysiology of human metabolic disorders, has limited the sustainability and efficacy of current pharmacological options. Emerging insights into the molecular origins of eating behaviour, energy expenditure, dyslipidaemia and insulin resistance suggest that coordinated targeting of multiple signalling pathways is probably necessary for sizeable improvements to reverse the progression of these diseases. Accordingly, a broad set of combinatorial approaches targeting feeding circuits, energy expenditure and glucose metabolism in concert are currently being explored and developed. Notably, several classes of peptide-based multi-agonists and peptide-small molecule conjugates with superior preclinical efficacy have emerged and are currently undergoing clinical evaluation. Here, we summarize advances over the past decade in combination pharmacotherapy for the management of obesity and type 2 diabetes mellitus, exclusively focusing on large-molecule formats (notably enteroendocrine peptides and proteins) and discuss the associated therapeutic opportunities and challenges.

Acquisition of analgesic properties by the cholecystokinin (CCK)/CCK2 receptor system within the amygdala in a persistent inflammatory pain condition.

Pain is associated with negative emotions such as anxiety, but the underlying neurocircuitry and modulators of the association of pain and anxiety remain unclear. The neuropeptide cholecystokinin (CCK) has both pronociceptive and anxiogenic properties, so we explored the role of CCK in anxiety and nociception in the central amygdala (CeA), a key area in control of emotions and descending pain pathways. Local infusion of CCK into the CeA of control rats increased anxiety, as measured in the light-dark box test, but had no effect on mechanical sensitivity. By contrast, intra-CeA CCK infusion 4 days after Complete Freund's Adjuvant (CFA) injection into the hindpaw resulted in analgesia, but also in loss of its anxiogenic capacity. Inflammatory conditions induced changes in the CeA CCK signaling system with an increase of CCK immunoreactivity and a decrease in CCK1, but not CCK2, receptor mRNA. In CFA rats, patch-clamp experiments revealed that CCK infusion increased CeA neuron excitability. It also partially blocked the discharge of wide dynamic range neurons in the dorsal spinal cord. These effects of CCK on CeA and spinal neurons in CFA rats were mimicked by the specific CCK2 receptor agonist, gastrin. This analgesic effect was likely mediated by identified CeA neurons projecting to the periaqueductal gray matter that express CCK receptors. Together, our data demonstrate that intra-CeA CCK infusion activated a descending CCK2 receptor-dependent pathway that inhibited spinal neuron discharge. Thus, persistent pain induces a functional switch to a newly identified analgesic capacity of CCK in the amygdala, indicating central emotion-related circuit controls pain transmission in spinal cord.

Combination therapy with epidermal growth factor and gastrin delays autoimmune diabetes recurrence in nonobese diabetic mice transplanted with syngeneic islets.

In a previous study, we observed that combination therapy of nonobese diabetic (NOD) mice with epidermal growth factor (EGF) and gastrin partially restored pancreatic islet beta-cell mass and reversed hyperglycemia without the use of immunotherapy. Herein we have studied the effects of EGF plus gastrin on recurrent autoimmune responses in diabetic NOD mice transplanted with syngeneic islets. EGF (10 microg/kg) plus gastrin (30 microg/kg) given intraperitoneally (i.p.) once daily to diabetic NOD mice (blood glucose, 23 +/- 2 mmol/L) significantly prolonged the median survival time of NOD islet grafts to 60 days (n = 10 mice) measured as the days until hyperglycemia recurrence (blood glucose > or =12 mmol/L; versus EGF alone to 36 days (n = 10), or gastrin alone, 19 days (n = 10), or vehicle, 11 days (n = 9). At 7-14 days after transplantation insulin-stained beta-cells were much more numerous in islet grafts of EGF plus gastrin-treated mice (13.0 +/- 0.9 x 10(5) cells) versus grafts in vehicle-treated mice (1.0 +/- 0.3 x 10(5) cells). CD45+ leukocytes were significantly reduced in number and surrounded but did not destroy the beta cells in the islets of EGF plus gastrin-treated mice (29 +/- 2 x 10(5) cells) versus those in vehicle-treated mice (57 +/- 3 x 10(5) cells). We concluded that the EGF plus gastrin combination therapy inhibited the recurrent autoimmune response and delayed rejection of syngeneic islet grafts, suggesting a therapeutic role for these peptides in islet transplantation.

Clearance and acid-stimulating action of human big and little gastrins in duodenal ulcer subjects.

Acid-stimulating action and clearance of pure natural human big gastriin (HG-34-I) and little gastrin (HG-17-I) were assessed in four male subjects with inactive duodenal ulcer (DU) disease. Disappearance half-times for HG-17-I after intravenous infusion (5.2 min) or rapid intravenous injection (6.4 min) were six to eight times shorter than those for HG-34-I (41.5 and 37.8 min, respectively). Studies of clearance of synthetic human little gastrin (HG-17-I) were performed in three of these same four DU subjects, eight additional male DU subjects, and eleven normal male subjects. The disappearance halftime of synthetic HG-17-I averaged 6.2 min in both the DU subjects and the normal subjects. These data suggest that clearance of exogenous gastrin is not altered in patients with DU. Acid secretion in response to rapid intravenous injection of HG-34-I reached a higher peak and lasted longer than in response to an equimolar dose of HG-17-I; the total response to HG-34-I was about three times that to HG-17-I. During constant intravenous infusion, acid responses to equimolar exogenous doses of the two peptides were similar but the increment in molar concentration of circulating gastrin was six to eight times greater with HG-34-I than with HG-17-I. Chromatography of serum obtained during infusions of HG-34-I revealed no evidence of conversion to HG-17-I, nor was there any increase in circulating G-34 activity during infusions of HG-17-I. The increment in serum gastrin concentration required to produce half-maximal stimulation of gastric acid secretion (D50) was estimated in each subject for each gastrin from curves relating acid secretion to change in serum gastrin concentration produced by infusion of these peptides. After instilling peptone solution into the stomach, acid secretion was measured by intragastric titration, and increases in circulating G-17 and G-34 were determined by chromatography and radioimmunoassay of serum. Increases in circulating G-17 and G-34 in response to the peptone meal, taken together, were equivalent to 1.5 times the D50 determined from infusions of G-34 and G-17. Acid secretion during the same time period averaged 55% of maximal rates. Although G-34 comprised approximately three-fourths of the total molar concentration of circulating gastrin after stimulation, it was estimated to contribute less than half of the acid-stimulating activity.

Cholecystokinin-B/gastrin receptors enhance wound healing in the rat gastric mucosa.

Although physiological functions of the CCK-B/gastrin receptor are well explored, little is known about its role during healing. Here, we evaluated the role of this receptor in the rat oxyntic mucosa following the introduction of a cryoulcer. In this model, we located and quantified CCK-B/gastrin receptors by reverse transcriptase PCR and receptor autoradiography. Rats with cryoulcers were treated with placebo, omeprazole, the CCK-B/gastrin receptor antagonist YF-476, omeprazole plus YF-476, gastrin-17, and gastrin 17 plus YF-476. During wound healing, CCK-B/gastrin receptors were specifically expressed and localized to the regenerative mucosal ulcer margin. This high expression was limited in time, and the pattern of expression of CCK-B/gastrin receptors correlated closely with the proliferative activity of the regenerative mucosa. Functionally, omeprazole and gastrin-17 caused profound hypergastrinemia, increased cell proliferation in the mucosal ulcer margin and accelerated the late ulcer healing phase. These effects were completely reversed by cotherapy with YF-476. These in vivo and vitro data suggest that CCK-B/gastrin receptors in regenerative rat gastric oxyntic mucosa enhance trophic effects during wound healing.

What's new in pancreatic cancer treatment pipeline?

There is still a substantial need for the development of new treatments for patients with pancreatic cancer. In this chapter, we will document that there is quite a bit of an increase in research activity with development in two major areas including (1) agents in the pipeline which already have hints of antitumor activity in patients with pancreatic cancer (therapeutic monoclonal antibodies and vaccines as well as more conventional cytotoxics), and; (2) agents in the pipeline which have just started (or will soon start) in clinical trial. These agents range from a gene-therapy approach to radiation enhancement to inhibitors of protein with increased expression in the very hypoxic pancreatic cancer tissue, to new monoclonal antibodies. With the level of investigational activity in pancreatic cancer it is very likely that several new therapeutic approaches to the disease will be forthcoming.

The effect of jaundice on the generation of anti-gastrin antibodies in G17DT immunized patients with advanced pancreatic cancer.

AIM: The aim of this study was to determine the ability of G17DT to generate anti-gastrin antibodies in jaundiced patients with biliary obstruction due to advanced pancreatic cancer. METHODS: G17DT was administered to 41 patients with advanced pancreatic adenocarcinoma by intramuscular (i.m.) injection at a dose of 250mcg at weeks 0, 1 and 3 of the study. RESULTS: Thirty-five of 41 patients participating in the study were categorized as responders in terms of their gastrin-17 antibody response. There was no correlation between the maximum G17 antibody response and the bilirubin level at either week 0 or week 12. The median survival of patients from the time of the first injection of G17DT was 204 days with 25% of patients surviving for or=305 days. CONCLUSION: This study shows that G17DT administered to jaundiced patients with advanced pancreatic cancer is immunogenic and well tolerated.

Gastrimmune raises antibodies that neutralize amidated and glycine-extended gastrin-17 and inhibit the growth of colon cancer.

The effect of gastrin neutralization was evaluated on the in vivo growth of the rat colon line, DHDK12, which expressed cholecystokinin B/gastrin receptors and secreted glycine-extended gastrin-17 (G17). Gastrin neutralization was achieved by administration of the immunogen, Gastrimmune, which is composed of the amino terminal portion of G17 linked to a diphtheria toxoid. A rat-specific version of Gastrimmune was used to preimmunize rats, with control animals receiving diphtheria toxoid only. The antibodies raised neutralized both carboxy-amidated and glycine-extended G17. The tumor was implanted into the muscle layer of the abdominal wall, and rats immunized with Gastrimmune had significantly reduced median cross-sectional tumor areas (70.2% reduction; P = 0.005) and weights (56.5% reduction; P = 0.0078)) when compared to control rats. Histological analysis revealed that the tumors had an enhanced degree of necrosis, with the area of viable tumor in the Gastrimmune-immunized rat reduced to 40.3% compared to 58.6% in the control rats (P = 0.003). Immunization with Gastrimmune raised antibodies that inhibited the growth of a rat colon tumor. This could have been mediated by neutralization of both serum G17 and cell-associated precursor gastrin molecules.

From preclinical development to clinical application: Kit formulation for radiolabelling the minigastrin analogue CP04 with In-111 for a first-in-human clinical trial.

INTRODUCTION: A variety of radiolabelled minigastrin analogues targeting the cholecystokinin 2 (CCK2) receptor were developed and compared in a concerted preclinical testing to select the most promising radiotracer for diagnosis and treatment of medullary thyroid carcinoma (MTC). DOTA-DGlu-DGlu-DGlu-DGlu-DGlu-DGlu-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2 (CP04) after labelling with (111)In displayed excellent characteristics, such as high stability, receptor affinity, specific and persistent tumour uptake and low kidney retention in animal models. Therefore, it was selected for further clinical evaluation within the ERA-NET project GRAN-T-MTC. Here we report on the development of a pharmaceutical freeze-dried formulation of the precursor CP04 for a first multi-centre clinical trial with (111)In-CP04 in MTC patients. MATERIALS AND METHODS: The kit formulation was optimised by adjustment of buffer, additives and radiolabelling conditions. Three clinical grade batches of a final kit formulation with two different amounts of peptide (10 or 50 µg) were prepared and radiolabelled with (111)In. Quality control and stability assays of both the kits and the resulting radiolabelled compound were performed by HPLC analysis. RESULTS: Use of ascorbic acid buffer (pH4.5) allowed freeze-drying of the kit formulation with satisfactory pellet-formation. Addition of methionine and gentisic acid as well as careful selection of radiolabelling temperature was required to avoid extensive oxidation of the Met(11)-residue. Trace metal contamination, in particular Zn, was found to be a major challenge during the pharmaceutical filling process in particular for the 10 µg formulation. The final formulations contained 10 or 50 µg CP04, 25mg ascorbic acid, 0.5mg gentisic acid and 5mg L-methionine. The radiolabelling performed by incubation of 200-250 MBq (111)InCl3 at 90 °C for 15 min resulted in reproducible radiochemical purity (RCP) >94%. Kit-stability was proven for >6 months at +5 °C and at +25 °C. The radiolabelled product was stable for >4h at +25 °C. CONCLUSION: A kit formulation to prepare (111)In-CP04 for clinical application was developed, showing high stability of the kit as well as high RCP of the final product.