Secretin stimulates biliary cell proliferation by regulating expression of microRNA 125b and microRNA let7a in mice.

BACKGROUND & AIMS: Proliferating cholangiocytes secrete and respond to neuroendocrine hormones, including secretin. We investigated whether secretin secreted by S cells and cholangiocytes stimulates biliary proliferation in mice. METHODS: Cholestasis was induced in secretin knockout (Sct(-/-)) and wild-type (control) mice by bile duct ligation (BDL). At days 3 and 7 after BDL, control and Sct(-/-) mice received tail-vein injections of morpholinos against microRNA 125b or let7a. One week later, liver tissues and cholangiocytes were collected. Immunohistochemical, immunoblot, luciferase reporter, and real-time polymerase chain reaction assays were performed. Intrahepatic bile duct mass (IBDM) and proliferation were measured. Secretin secretion was measured in conditioned media from cholangiocytes and S cells and in serum and bile. RESULTS: Secretin secretion was increased in supernatants from cholangiocytes and S cells and in serum and bile after BDL in control mice. BDL Sct(-/-) mice had lower IBDM, reduced proliferation, and reduced production of vascular endothelial growth factor (VEGF) A and nerve growth factor (NGF) compared with BDL control. BDL and control mice given morpholinos against microRNA 125b or let7a had increased IBDM. Livers of mice given morpholinos against microRNA 125b had increased expression of VEGFA, and those treated with morpholinos against microRNA let7a had increased expression of NGF. Secretin regulated VEGF and NGF expression that negatively correlated with microRNA 125b and let7a levels in liver tissue. CONCLUSIONS: After liver injury, secretin produced by cholangiocytes and S cells reduces microRNA 125b and let7a levels, resulting in up-regulation of VEGF and NGF. Modulation of cholangiocyte expression of secretin could be a therapeutic approach for biliary diseases.

Dietary sodium butyrate supplementation increases digestibility and pancreatic secretion in young milk-fed calves.

The aim of this study was to test, in 8 calves fed milk formula based on soybean protein, the ability of sodium butyrate (SB) supplementation to improve nutrient digestibility and daily pancreatic secretions and to modify the kinetics of these secretions. Additionally, effects of duodenal SB infusion were evaluated. Plasma levels of gastrin, secretin, and cholecystokinin were measured. Butyrate supplementation in milk formula increased nutrient digestibility and total daily pancreatic secretions. For juice volume, this increase was most important from 12 to 17h after the morning meal. During the 3-h postprandial period, oral SB supplementation reduced the physiological decrease of postprandial pancreatic secretion (while duodenal digesta flow rate was maximal) and had a minor effect on plasma gut regulatory peptide concentrations. Compared with the diet without SB, ingestion of SB stimulated pancreatic secretion. Taken together, these results could explain the measured increase in nutrient digestibility. The data obtained after duodenal SB infusion did not indicate an effect on pancreatic secretion, apart from elevated lipase output compared with control. The mechanisms responsible for these events are not known and circulating gut regulatory peptides do not seem to be implicated. Our work brings new results regarding SB as a feed additive in young calf nutrition.

Oxyntomodulin increases the concentrations of insulin and glucose in plasma but does not affect ghrelin secretion in Holstein cattle under normal physiological conditions.

Ghrelin, the natural ligand of the growth hormone secretagogue receptor (GHS-R1a), has been shown to stimulate growth hormone (GH) secretion. Regulation of ghrelin secretion in ruminants is not well studied. We investigated the effects of oxyntomodulin (OXM) and secretin on the secretions of ghrelin, insulin, glucagon, glucose, and nonesterified fatty acids (NEFA) in pre-ruminants (5 wk old) and ruminants (10 wk old) under normal physiological (feeding) conditions. Eight male Holstein calves (pre-ruminants: 52 +/- 1 kg body weight [BW]; and ruminants: 85 +/- 1 kg BW) were injected intravenously with 30 microg of OXM/kg BW, 50 microg of secretin/kg BW, and vehicle (0.1% bovine serum albumin [BSA] in saline as a control) in random order. Blood samples were collected, and plasma hormones and metabolites were analyzed using a double-antibody radioimmunoassay system and commercially available kits, respectively. We found that OXM increased the concentrations of insulin and glucose but did not affect the concentrations of ghrelin in both pre-ruminants and ruminants and that there was no effect of secretin on the concentrations of ghrelin, insulin, and glucose in these calves. We also investigated the dose-response effects of OXM on the secretion of insulin and glucose in 8 Holstein steers (401 +/- 1 d old, 398 +/- 10 kg BW). We found that OXM increased the concentrations of insulin and glucose even at physiological plasma concentrations, with a minimum effective dose of 0.4 microg/kg for the promotion of glucose secretion and 2 microg/kg for the stimulation of insulin secretion. These findings suggest that OXM takes part in glucose metabolism in ruminants.

[Changes in concentration of cholecystokinin-pancreozymin in patients with cholelithiasis before and after cholecystectomy].

The level of cholecystokinin and secretin in 50 patients after cholecystectomy (from 1 to 10 years ago) was analyzed to study connection between cholecystectomy and gastrointestinal hormones concentration. 30 patients with gall bladder stone disease were included into the group of comparison. Cholecystokinin and secretin concentration in the groups of research was compared with indicated hormones concentration in the group of control formed of healthy volunteers. After anamnestical clinical and diagnostical features in every group had been studied we concluded, that cholecystokinin level changes depending on period after operation and outflow of bile conditions.

Effects of early enteral feeding on fecal elastase 1 and plasma secretin.

BACKGROUND: Enteral feeding is known to be effective on the development of gut hormone secretion and pancreatic exocrine function. The aim of the present study was to examine the effects of extremely early enteral feedings on the development in very low-birthweight (VLBW) infants. METHODS: Fecal elastase 1 and plasma secretin concentrations were measured at four different periods during the first 28 days of life in VLBW infants, with extremely early enteral feeding starting within 24 h of birth, as well as in control infants. RESULTS: Fecal concentrations of elastase 1 at 7, 14 and 28 days after birth were significantly higher than those at 1 or 2 days in both the early feeding and control groups. Fecal elastase 1 levels in the early feeding group were significantly higher than those in the control group at 7 and 14 days after birth. The plasma concentration of secretin at 14 days after birth was significantly higher than that at 1 or 2 days and 7 days after birth in the early feeding group. No significant differences in plasma secretin levels were detected between the early feeding and control groups at 1 or 2 days, 7 days and 28 days after birth, but a significant difference in secretin level was observed between the two groups at 14 days after birth. CONCLUSIONS: Extremely early enteral feedings may play an important role in the development of pancreatic exocrine function and secretin secretion in the early period of life in VLBW infants.

Secretin as a neurohypophysial factor regulating body water homeostasis.

Hypothalamic magnocellular neurons express either one of the neurohypophysial hormones, vasopressin or oxytocin, along with different neuropeptides or neuromodulators. Axonal terminals of these neurons are generally accepted to release solely the two hormones but not others into the circulation. Here, we show that secretin, originally isolated from upper intestinal mucosal extract, is present throughout the hypothalamo-neurohypophysial axis and that it is released from the posterior pituitary under plasma hyperosmolality conditions. In the hypothalamus, it stimulates vasopressin expression and release. Considering these findings together with our previous findings that show a direct effect of secretin on renal water reabsorption, we propose here that secretin works at multiple levels in the hypothalamus, pituitary, and kidney to regulate water homeostasis. Findings presented here challenge previous understanding regarding the neurohypophysis and could provide new concepts in treating disorders related to osmoregulation.

[Etiology and pathogenesis of duodenal mucosa lesion in chronic pancreatitis].

AIM: To measure content of neuromediators (acetylcholine-Ach, serotonin-5-NT) and gastrointestinal hormones (cholecystokinine-CCK and secretin) in the blood serum of patients with chronic pancreatitis (CP); to study protective properties of the mucus in the duodenum in CP. MATERIAL AND METHODS: CCK and secretin concentrations were estimated by enzyme immunoassay, Ach and 5-NT were measured biochemically basally and after standard meal in 65 CP patients and in the control group. Proteolytic activity of the mucus was assessed by Anson's method. An inhibitory property of the mucus was studied by residual proteolytic activity of pepsine after its incubation with mucus. RESULTS: In AP patients the response of biologically active substrates to standard meal changed: 5-NT concentration rose from 0.40 +/- 0.07 to 0.55 +/- 0.05 mcg/ml (p < 0.05) while Ach dropped from 1.7 +/- 0.3 to 1.6 +/- 0.3 mmol/l (p > 0.05). BP patients responded to the standard meal with 5-HT concentration rise from 0.28 +/- 0.04 to 0.43 +/- 0.05 mcg/ml (p < 0.05), Ach changed insignificantly (from 1.5 +/- 0.12 to 1.45 +/- 0.21 mmol/l, p > 0.05, reselectively). CCK after standard meal significantly rose both in AP and BP. AP and BP patients had strong direct correlation between concentrations of 5-HT and CCK (r = 0.875439) and weak negative correlation with Ach level (r = -0.2209). In AP and BP patients secretin level weakly negatively correlated both with 5-NT and Ach levels (r = -0.4839 and r = -0.33207, respectively). Reduction of secretin secretion diminished secretion of bicarbonates and mucus with simultaneous change in the quality of mucous gel. CONCLUSION: In CP of various etiology there are changes in the level and proportions of neuromediators and hormones causing alterations in the regulation system. These disorders correlate with disturbances in pancreatic excretory function and destructive tissue changes. Bicarbonates secretion decreases and changes quality of the secreted mucus.

[Exocrine function of the pancreas at chronic pancreatitis: diagnosis an drug correction].

Estimation of respiratory test with 13C- mixed triglytcherides and gastrointestinal hormones effeciancy for the diagnosis of extrasecretory pancreatic with chronic pancreatitis was the aim of this examination. Test 13C- mixed triglytcherides was examined vercus test with pancreatic elastase of feces (E-1). 45 patients with chronic pancreatitis and 20 patients in 2 control groups were examined. The resuets testify to the lowering of pancreatic exocrine function in the patients with complicated chronic pancreatitis. The levels of E-1 and CPRDF (360) were trustworthy low the patients with complicated chronic pancreatitis versus the patients with chronic pancreatitis without complications and in control groups (p < 0.05). Correlative analysis the levels of E-1 and CPRDF (360) had demonstrated high degrel of results similarity. Persons correlation index was r = 0.64 (p < 0.001). The secretines level after standart breakfast in the patients with chronic pancreatitis was lowering, but was increasing in the healthy persons. Secretine lowering may lead to the bicarbonates secretion lowering. These results testify to the necessity of fermental treatment in the patients with chronic pancreatitis accordingly the pancreatitis stage.

Phenotypes developed in secretin receptor-null mice indicated a role for secretin in regulating renal water reabsorption.

Aquaporin 2 (AQP2) is responsible for regulating the concentration of urine in the collecting tubules of the kidney under the control of vasopressin (Vp). Studies using Vp-deficient Brattleboro rats, however, indicated the existence of substantial Vp-independent mechanisms for membrane insertion, as well as transcriptional regulation, of this water channel. The Vp-independent mechanism(s) is clinically relevant to patients with X-linked nephrogenic diabetes insipidus (NDI) by therapeutically bypassing the dysfunctional Vp receptor. On the basis of studies with secretin receptor-null (SCTR(-/-)) mice, we report here for the first time that mutation of the SCTR gene could lead to mild polydipsia and polyuria. Additionally, SCTR(-/-) mice were shown to have reduced renal expression of AQP2 and AQP4, as well as altered glomerular and tubular morphology, suggesting possible disturbances in the filtration and/or water reabsorption process in these animals. By using SCTR(-/-) mice as controls and comparing them with wild-type animals, we performed both in vivo and in vitro studies that demonstrated a role for secretin in stimulating (i) AQP2 translocation from intracellular vesicles to the plasma membrane in renal medullary tubules and (ii) expression of this water channel under hyperosmotic conditions. The present study therefore provides information for at least one of the Vp-independent mechanisms that modulate the process of renal water reabsorption. Future investigations in this direction should be important in developing therapeutic means for treating NDI patients.

[The duodenal wall injury as a cause of acute pancreatitis].

Dynamics of cholecystokinin-like, secretin and somatostatin immunoreactivity of blood plasma and extracts of duodenal mucosa, frequency of acute pancreatitis (AP) after the resection of the duodenum was studied on not purebred dogs. Rising of a secretin concentration in blood plasma after the clinoid resection of the duodenum, accompanied by decreasing of its concentration in duodenal mucosa, was revealed. Decreasing of cholecystokinin concentration in a neutral extract was revealed. In 24 hours alter resection of the duodenum AP was observed in 38% of cases, infusion of the lorglumide was reduced the frequency of this complication up to 6.2% (p<0.05).

Serum gastrin in Zollinger-Ellison syndrome: II. Prospective study of gastrin provocative testing in 293 patients from the National Institutes of Health and comparison with 537 cases from the literature. evaluation of diagnostic criteria, proposal of new criteria, and correlations with clinical and tumoral features.

In two-thirds of patients with Zollinger-Ellison syndrome (ZES), fasting serum gastrin (FSG) levels overlap with values seen in other conditions. In these patients, gastrin provocative tests are needed to establish the diagnosis of ZES. Whereas numerous gastrin provocative tests have been proposed, only the secretin, calcium, and meal tests are widely used today. Many studies have analyzed gastrin provocative test results in ZES, but they are limited by small patient numbers and methodologic differences. To address this issue, we report the results of a prospective National Institutes of Health (NIH) study of gastrin provocative tests in 293 patients with ZES and compare these data with those from 537 ZES and 462 non-ZES patients from the literature. In 97%-99% of gastrinoma patients, an increase in serum gastrin post secretin (Delta secretin) or post calcium (Delta calcium) occurred. In NIH ZES patients with <10-fold increase in FSG, the sensitivity/specificity of the widely used criteria were as follows: Delta secretin > or =200 pg/mL (83%/100%), Delta secretin >50% (86%/93%), Delta calcium > or =395 pg/mL (54%/100%), and Delta calcium >50% (78%/83%). A systematic analysis of the sensitivity and specificity of other possible criteria for a positive secretin or calcium test allowed us to identify a new criterion for secretin testing (Delta > or =120 pg/mL) with the highest sensitivity/specificity (94%/100%) and to confirm the commonly used criterion for calcium tests (Delta > or =395 pg/mL) (62%/100%). This analysis further showed that the secretin test was more sensitive than the calcium test (94% vs. 62%). Our results suggest that secretin stimulation should be used as the first-line provocative test because of its greater sensitivity and simplicity and lack of side effects. In ZES patients with a negative secretin test, 38%-50% have a positive calcium test. Therefore the calcium test should be considered in patients with a strong clinical suspicion of ZES but a negative secretin test. Furthermore, we found that some clinical (diarrhea, duration of medical treatment), laboratory (basal acid output), and tumoral (size, extent) characteristics correlate with the serum gastrin increase post secretin and post calcium. However, using the proposed criteria, the result of these provocative tests (that is, positive or negative) is minimally influenced by these factors, so secretin and calcium provocative tests are reliable in patients with different clinical, laboratory, and tumor characteristics. A systematic analysis of meal testing showed that 54%-77% of ZES patients have a <50% postprandial serum gastrin increase. However, 9%-20% of ZES patients had a >100% increase post meal, causing significant overlap with antral syndromes. Furthermore, we could not confirm the usefulness of meal tests for localization of duodenal gastrinomas. We conclude that the secretin test is a crucial element in the diagnosis of most ZES patients, the calcium test may be useful in selected patients, but the meal test is not helpful in the management of ZES. For secretin testing, the criterion with the highest sensitivity and specificity is an increase of > or =120 pg/mL, which should replace other criteria commonly used today.

[Clinicopharmacological study of gastrointestinal drugs from the viewpoint of postmarketing development].

Pharmaceutical development starts with the discovery of a new compound. Drugs become commercially available after non-clinical and clinical studies, but processes that take place after marketing are also important for pharmaceutical development. In recent years, use of the phrase "Ikuyaku" meaning postmarketing development has become more common. Sometimes, the proper usage, indications and harmful effects of a drug are discovered only after it becomes commercially available and is administered to many patients. Hence, pharmacists need to actively perform postmarketing studies to reveal the true nature of drugs. In the present clinicopharmacological study, we investigated the effects of histamine H(2) receptor antagonists (H(2)-RAs) on the plasma concentrations of gastrointestinal peptides from the viewpoint of postmarketing development. First we established an enzyme immunoassay for secretin, which is involved in gastrointestinal motility. Then we used this and existing peptide assays to investigate the above-mentioned issues. Ranitidine and nizatidine increased the plasma concentration of motilin. It is believed that the plasma concentration of Ach is elevated by ranitidine and nizatidine, which possesses an anti-AchE activity, and that the increased the plasma concentration of Ach facilitated release of motilin, elevating the plasma concentration of motilin. When compared to the placebo, lafutidine significantly increased the plasma concentration of CGRP (calcitonin gene-related peptide) and substance P. Furthermore, released CGRP stimulated CGRP1 receptors to facilitate secretion of somatostatin. Therefore, lafutidine appears to protect the gastric mucosa and regulate gastrointestinal motility. The same results were obtained with ranitidine and nizatidine. While H(2)-RAs have a common function in suppressing the secretion of gastric acid, they do not exhibit the same effects on factors related to recurrence of peptic ulcer, such as gastrointestinal motility and blood flow in the gastrointestinal mucosa. Hence, measuring the plasma concentration of gastrointestinal peptides can be used to estimate the effects of drugs on gastrointestinal motility. From the viewpoint of postmarketing development, we are in the process of establishing indicators for the proper usage of pharmaceutical drugs. Pharmacists need to closely follow and monitor adverse reactions. In order to further improve monitoring of drug therapy, it will be necessary to assess not only the blood concentrations of drugs, but also biological reactions to the drugs. Since the levels of peptides reflect the clinical efficacy of gastrointestinal drugs, measuring peptide levels appears to be useful for selecting appropriate drugs.

Dietary acetic acid reduces serum cholesterol and triacylglycerols in rats fed a cholesterol-rich diet.

To investigate the efficacy of the intake of vinegar for prevention of hyperlipidaemia, we examined the effect of dietary acetic acid, the main component of vinegar, on serum lipid values in rats fed a diet containing 1 % (w/w) cholesterol. Animals were allowed free access to a diet containing no cholesterol, a diet containing 1 % cholesterol without acetic acid, or a diet containing 1 % cholesterol with 0.3 % (w/w) acetic acid for 19 d. Then, they were killed after food deprivation for 7 h. Cholesterol feeding increased serum total cholesterol and triacylglycerol levels. Compared with the cholesterol-fed group, the cholesterol and acetic acid-fed group had significantly lower values for serum total cholesterol and triacylglycerols, liver ATP citrate lyase (ATP-CL) activity, and liver 3-hydroxy-3-methylglutaryl-CoA content as well as liver mRNA levels of sterol regulatory element binding protein-1, ATP-CL and fatty acid synthase (P<0.05). Further, the serum secretin level, liver acyl-CoA oxidase expression, and faecal bile acid content were significantly higher in the cholesterol and acetic acid-fed group than in the cholesterol-fed group (P<0.05). However, acetic acid feeding affected neither the mRNA level nor activity of cholesterol 7alpha-hydroxylase. In conclusion, dietary acetic acid reduced serum total cholesterol and triacylglycerol: first due to the inhibition of lipogenesis in liver; second due to the increment in faecal bile acid excretion in rats fed a diet containing cholesterol.

[Recent trend of diagnosis and treatment for Zollinger-Ellison syndrome].

Since 1955 it has been difficult to cure gastrinomas in patients with Zollinger-Ellison Syndrome (ZES), because gastrinomas exhibit symptoms when they are still small. Besides they are often multiple and metastatic. Development of the SASI test and SRS has changed the situation, and now, based on these two techniques, curative resection of gastrinomas in ZES can be routinely performed. As the cases of resection increase, more accurate pathological findings have accumulated. We know now that duodenal gastrinomas have been a cause of ZES in more patients than pancreatic gastrinomas. In most patients with MEN-1 and ZES, duodenal gastrinomas, which are often multiple, bring about ZES.

Sudden onset of colitis after ablation of secretin-expressing lymphocytes in transgenic mice.

Though secretin mRNA was demonstrated in mouse lymphoid organs, its role in the immune system is unknown. Here, secretin gene-expressing cells were ablated by ganciclovir infusion in mice transgenic for the rat secretin promoter (Sec) directing the expression of herpesvirus thymidine kinase (Sec-HSVTK). Thymus, spleen, blood, and colon were investigated by histology. Lymphoid cells were extracted and quantified, and CD19+ B-cells and CD3+, CD103+, CD4+, and CD8+ T-cells were analyzed by flow cytometry. Protein extracts from spleen and thymus were assayed for secretin by Western blotting, and isolated lymphocytes were investigated for HSVTK, secretin, and secretin receptor (Sec-R) mRNA by reverse transcription-polymerase chain reaction (RT-PCR). Ablation of secretin-expressing cells produced severe colitis with morphological features similar to those observed in graft-versus-host (GVH) disease. Profound lymphoid depletion was observed in spleen, thymus, and peripheral blood. The relative percentage of B- and T-cell subsets were unaffected. Analysis of colonic lymphocytes revealed a marked depletion of CD4+ T lymphocytes. Colitis and lymphoid depletion were not reversed by secretin cotreatment. Immunoblot analysis of protein extracts from spleen and thymus identified secretin-like immmunoreactant. RT-PCR of lymphocyte mRNA from spleen and thymus identified secretin and secretin receptor transcripts. We conclude that GVH-like colitis in ganciclovir-treated Sec-HSVTK mice arises from depletion of secretin gene-expressing lymphoid cells and not from the failure of secretin production.

Parenteral versus early intrajejunal nutrition: effect on pancreatitic natural course, entero-hormones release and its efficacy on dogs with acute pancreatitis.

AIM: To evaluate the effect of early intrajejunal nutrition (EIN) on the natural course, entero-hormone secretion and its efficacy on dogs with acute pancreatitis. METHODS: An acute pancreatitis model was induced by injecting 1 ml/kg of combined solution (2.5% sodium taurocholate and 8,000-10,000 BAEE units trypsin/ml) into the pancreas via pancreatic duct. Fifteen dogs were divided into parenteral nutrition (PN) group and EIN group. Two groups were isonitrogenous and isocaloric. EIN was used at postoperative 24 h. Serum glucose, calcium, amylase and lysosomal enzymes were determined before and 1, 4, 7 d after acute pancreatitis was induced. All the dogs were injected 50 uCi 125I-BSA 4 h before sacrificed on the 7th day. The 125I -BSA index of the pancreas/muscle, pancreas/blood, and pancreas pathology score (PPS) were determined. The peripheral plasma cholecystokinin (CCK), secretin (SEC) and gastrin were measured by ELISA and RIA, and was quantitative analysis of pancreatic juice and amylase, pancreatolipase and HCO3-, Cl-, Na+ and K+ performed by an autochemical analyzer at 30, 60, 120 and 180 min after beginning PN or EIN on the first day. RESULTS: There was no difference between two groups in the contents of serum calcium, amylase and lysosomal enzymes, 125I-BSA index of pancreas/muscle and pancreas/blood and PPS. The contents of CCK and gastrin in EIN were higher than those in PN group at 60 and 120 min (P<0.05). The content of SEC post-infusion of nutrition solution was higher than that of pre-infusion of nutrition solution in both groups, and only at 60 min SEC in EIN group was higher than that in PN group. The content of gastrin in EIN was higher than that in PN group at 120 and 180 min (P<0.05). The changes of pancreatic juice, amylase, pancreatolipase and HCO3-, Cl-, Na+ and K+ between two groups did not reach significantly statistical difference (P>0.05). CONCLUSION: EIN does not stimulate entero-hormone and pancreatic juice secretion, and enzyme-protein synthesis and release. EIN has no effect on the natural course of acute pancreatitis.

Lafutidine changes levels of somatostatin, calcitonin gene-related peptide, and secretin in human plasma.

We examined the effects of the histamine H2-receptor antagonist, lafutidine, on the levels of gastrointestinal peptides (somatostatin, calcitonin gene-related peptide (CGRP), gastrin, secretin, and motilin) in plasma from healthy subjects. After a single oral administration of lafutidine (10 mg), the plasma lafutidine level (186 +/- 13.4ng/ml) was highest in the 60-min sample after administration and then the plasma level fell. Lafutidine caused significant increase in plasma somatostatin levels at 20 to 120 min and in CGRP levels at 40 to 120 min, compared with a placebo group. The physiological release of plasma secretin was reduced by administration of lafutidine, but the medicine did not alter the level of gastrin or motilin. These results suggest that the pharmacological effects of lafutidine on regulation of gastrointestinal functions closely relate to changes of somatostatin-, CGRP- and secretin-immunoreactive substance levels in human plasma.