Peter Felderbauer

Pancreatitis risk in primary hyperparathyroidism: relation to mutations in the SPINK1 trypsin inhibitor (N34S) and the cystic fibrosis gene.

OBJECTIVEPrimary hyperparathyroidism (pHPT)-related hypercalcemia is considered to represent a risk factor for the development of pancreatitis. We therefore explored whether mutations in genes that were previously identified to increase the risk for pancreatitis coexist in a cohort of 826 patients with pHPT prospectively studied between 1987 and 2002.METHODSAmong 826 patients with pHPT, 38 patients were identified with pancreatitis (4.6%). DNA was available from 25 patients (13 women/12 men, 16 acute pancreatitis/9 chronic pancreatitis). These individuals and 50 patients with pHPT without pancreatitis were analyzed for mutations in the serine protease inhibitor Kazal type I (SPINK1) gene (N34S) and the cationic trypsinogen gene (PRSS1) (N29I, R122H) by melting curve analysis and DNA sequencing. Sequence analysis of the cystic fibrosis transmembrane conductance regulator (CFTR) gene was carried out for the detection of 36 mutations and the Tn polymorphism.RESULTSFour of 25 patients with pHPT and pancreatitis carried the N34S missense mutation in the SPINK1 gene (16%), while all 50 controls (pHPT without pancreatitis) showed no mutation in SPINK1 or PRSS1 genes (P < 0.05 vs controls, P < 0.001 vs general population). CF-causing CFTR mutations were present in four patients (P < 0.05 vs general population), while one patient carried a 5T allele. One patient was transheterozygous (SPINK1: N34S/CFTR: R553X). Mean serum calcium levels in pancreatitis patients (3.1 mmol/L) did not differ significantly from the mean of the entire cohort (3.0 mmol/L) or pHPT patients without pancreatitis (3.1 mmol/L).CONCLUSIONPancreatitis risk is approximately 10-fold elevated in pHPT, but pancreatitis occurs infrequently. This indicates an existing but minor impact of pHPT-related hypercalcemia. If pancreatitis occurs, it seems associated with genetic risk factors such as mutations in the SPINK1 and CFTR genes. In contrast, a combination of both hypercalcemia and genetic variants in SPINK1 or CFTR increases the risk to develop pancreatitis in patients with pHPT.

A novel mutation of the calcium sensing receptor gene is associated with chronic pancreatitis in a family with heterozygous SPINK1 mutations

BACKGROUND The role of mutations in the serine protease inhibitor Kazal type 1 (SPINK1) gene in chronic pancreatitis is still a matter of debate. Active SPINK1 is thought to antagonize activated trypsin. Cases of SPINK1 mutations, especially N34S, have been reported in a subset of patients with idiopathic chronic pancreatitis. However, the inheritance pattern is still unknown. Some cases with N34S heterozygosity have been reported with and without evidence for CP indicating neither an autosomal recessive nor dominant trait. Therefore SPINK1 mutations have been postulated to act as a disease modifier requiring additional mutations in a more complex genetic model. Familial hypocalciuric hypercalcemia (FHH) caused by heterozygous inactivating mutations in the calcium sensing receptor (CASR) gene is considered a benign disorder with elevated plasma calcium levels. Although hypercalcemia represents a risk factor for pancreatitis, increased rates of pancreatitis in patients with FHH have not been reported thus far. METHODS We studied a family with a FHH-related hypercalcemia and chronic pancreatitis. DNA samples were analysed for mutations within the cationic trypsinogen (N29I, R122H) and SPINK1 (N34S) gene using melting curve analysis. Mutations within CASR gene were identified by DNA sequencing. RESULTS A N34S SPINK1 mutation was found in all screened family members. However, only two family members developed chronic pancreatitis. These patients also had FHH caused by a novel, sporadic mutation in the CASR gene (518T>C) leading to an amino acid exchange (leucine->proline) in the extracellular domain of the CASR protein. CONCLUSION Mutations in the calcium sensing receptor gene might represent a novel as yet unidentified predisposing factor which may lead to an increased susceptibility for chronic pancreatitis. Moreover, this family analysis supports the hypothesis that SPINK1 mutations act as disease modifier and suggests an even more complex genetic model in SPINK1 related chronic pancreatitis.

Glucagon-like peptide 2 improves intestinal wound healing through induction of epithelial cell migration in vitro-evidence for a TGF-β-mediated effect

Abstract Background/aims: In vitro studies suggest that glucagon-like peptide 2 (GLP-2), secreted from enteroendocrine cells in the gastrointestinal tract after food intake, is able to ameliorate mucosal injury in settings of human disease characterized by injury and dysfunction of the intestinal mucosal epithelium. We evaluated this potential of GLP-2 after epithelial trauma by using two in vitro models measuring intestinal epithelial cell proliferation and cell migration. Materials and methods: Injuries were induced in confluent monolayers of the small intestinal cells lines IEC-6 and IEC-18, as well as in the colonic cell lines Caco-2 and Colo 320. GLP-2 (50–500 nM) or other peptides were added to the media. Wound healing was investigated after 24 h by quantification of the number of cells migrating across the wound edge. Proliferation of cells was assessed by using photometric mitochondrial incorporation measurement of MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide). Monoclonal TGF-β antibodies were added to wounded monolayers to examine whether the GLP-2-induced wound healing was TGF-β-mediated. Results: Migration assessments revealed a significant stimulation of GLP-2-induced migration in IEC-6 and IEC-18 monolayers compared to the placebo group. No effect was observed in the colon cancer cell lines Caco-2 and Colo 320. Results of the proliferation assays show a significant inhibition of proliferation by GLP-2 in small intestinal cell lines whereas a dose-dependent stimulation of proliferation in colonic epithelial cells was observed. Addition of neutralizing TGF-β1 antibodies to wounded IEC-6 and IEC-18 monolayers incubated with GLP-2 significantly reduced the number of migrating cells to the level of the placebo group. Conclusions: In our in vitro model, it was shown that the GLP-2-induced improvement of intestinal wound healing is TGF-β-mediated. These effects were predominant in the epithelium of the small intestine compared to colonic epithelium. Our findings provide further insight into mechanisms leading to GLP-2-induced mucosal wound healing. These results suggest that GLP-2 or analogues of this peptide may potentially be useful for the treatment of intestinal disorders characterized by injury and ineffective repair of the intestinal mucosa.

Mutations in the calcium-sensing receptor: A new genetic risk factor for chronic pancreatitis?

Objective. In 2003 we identified a family with familial hypocalciuric hypercalcemia (FHH) (heterozygous CASR gene mutation L173P) and a mutation in the pancreatic secretory trypsin inhibitor gene (SPINK1) (N34S). While family members with an isolated calcium-sensing receptor gene (CASR) mutation remained healthy, a combination of the CASR and SPINK1 gene mutation caused chronic pancreatitis (CP). We thus speculate that the combination of two genetic defects affecting calcium homeostasis and pancreatic enzyme activation might represent a novel approach in chronic inherited pancreatic disease. We therefore sought to explore whether CASR gene mutations were prevalent in a cohort of patients with CP and confirmed SPINK1 mutations. Material and methods. A cohort of 19 families (n=170) with a history of idiopathic CP (ICP) was screened for mutations within the CASR gene; 104 members of that cohort had a mutation (N34S) within the SPINK1 gene and 66 of those were suffering from CP. The entire CASR gene was screened for single strand conformation polymorphism under varying polyacrylamide gel conditions and subjected to direct dideoxy nucleotide sequencing of amplified cDNA. Results. Single-strand conformation polymorphisms were observed in 59 samples, clustering of exons 3, 4 and 7. DNA sequence analysis revealed a yet unreported missense mutation in exon 7 (R896H) and two conservative mutations in exon 4 (F391F) and exon 7 (E790E). Furthermore, an intronic polymorphism in nucleotide position 493-19 G > A was detected in 19 out of 170 members of that cohort. Conclusions. We identified three novel calcium-sensing receptor gene mutations (1 missense mutation, 2 silent mutations and 1 intronic polymorphism) in a cohort of 19 families with ICP. In particular, the kindred with the R896H mutation presenting with a similar pedigree to the family described above may indicate a role for CASR gene mutations in SPINK1-related CP. Again, only the patient with the combination of both CASR and N34S SPINK1 gene mutation developed pancreatitis, whereas in the healthy parents and children only an isolated CASR or N34S SPINK1 gene mutation could be detected. We suggest that the CASR gene is a novel yet undetected co-factor in a multifactorial genetic setting of SPINK1-related pancreatitis that alters the susceptibility for pancreatitis in these patients.

Bacteribilia after preoperative bile duct stenting: a prospective study.

Study Design A prospective analysis of intraoperative bile duct cultures in patients undergoing surgery for both, malignant or benign periampullary diseases at the Department of Surgery, St Josef Hospital, Bochum, Germany, during a period of 18 months, between January 2004 and June 2005. Goals The goals of the presented study were to investigate the effects of preoperative bile duct stenting on intraoperative bile duct cultures and postoperative outcome in patients undergoing pancreatic surgery. Background In pancreatic surgery, bile duct stenting is often aimed at improving postoperative outcome. As implantation of xenograft material in the main bile duct facilitates bacterial contamination and cholangitis, a critical evaluation of stenting is mandatory. Study In all patients with a hepaticojejunostomy (n=80), a bile duct culture was collected during the operation. All patients received antibiotic prophylaxis perioperatively and a retrograde flushing of bile ducts with warm saline after bile duct resection. Fifty-one percent (41/80) patients had biliary drainage before surgery, whereas 49% (39/80) were operated without preoperative draining procedures. Results After bile duct stenting, 98% of patients had a positive bile culture, whereas only 21% of infected bile was seen in patients without drainage (P<0.001). Despite infected bile, only 2% stented patients developed acute cholangitis postoperatively, versus 13% patients in the group without stent (P=0.231). After stenting, major complications occurred in 12%, versus 8% in patients without stent (P=0.817). Conclusions Preoperative biliary drainage leads to an almost 100% bacterial contamination of bile ducts. With hospital-adjusted antibiotic prophylaxis and retrograde flushing of bile ducts, the postoperative rate of acute cholangitis and morbidity is not elevated. A critical evaluation of benefits from preoperative biliary drainage for each patient is necessary.

A novel A121T mutation in human cationic trypsinogen associated with hereditary pancreatitis: Functional data indicating a loss-of-function mutation influencing the R122 trypsin cleavage site

Background: The understanding of genetic risk factors for chronic pancreatitis increased in the last decade with the discovery of mutations in the cationic trypsinogen gene (PRSS1). The first mutation was detected at the R122 autocleavage site of the protein (R122H) and subsequently two other mutations in this region, R122C and V123M, were described that resulted in a similar phenotype of hereditary pancreatitis. This study reports a novel A121T mutation within this region and characterises the resulting molecular properties at the autocleavage site. Methods: Blood samples of a PRSS1 A121T carrier family were analysed for PRSS1 mutations using melting point curve analysis, restriction endonucleases and DNA sequencing. Conformation dependent properties of the mutated sequence were analysed by molecular modelling. The autodegradation kinetic of the mutated trypsin sequence was measured by a novel fluorescence resonance energy transfer (FRET) assay using designed 11 amino acid peptides from PRSS1 aa 118 – aa 127 containing the trypsin cleavage site at aa 122 coupled to a Dabcyl/EDANS FRET system. The kinetic of tryptic peptide cleavage was measured in a fluorescence enzyme linked immunosorbent assay (ELISA) reader. Results: DNA sequencing revealed a novel G to A transition at position 133279 of the published genomic sequence (#U66061 GenBank). The mutation results in an amino acid substitution of alanine by threonine at position 121 (A121T) of the cationic trypsinogen. Four additional mutation carriers could be identified among the relatives while only the first patient developed chronic pancreatitis. Molecular modelling of PRSS1 A121T revealed a change in the bond pattern between the R122 region and the calcium binding loop, whereas FRET assays showed an increased trypsin cleavage rate with a reaction kinetic elevated by more than 80%. Conclusion: The novel PRSS1 A121T mutation highlights the surface exposed region PRSS1 A121-R122-V123 as a hotspot for hereditary pancreatitis associated trypsinogen mutations. Molecular modelling and FRET assays provide evidence for an A121T mutation dependent increase in susceptibility to trypsin digestion at the R122 cleavage site suggesting an enhanced autodegradation and a loss-of-function at the autocleavage site.

Vascular endothelial growth factor (VEGF164) ameliorates intestinal epithelial injury in vitro in IEC-18 and Caco-2 monolayers via induction of TGF-β release from epithelial cells

Objective. VEGF is a glycoprotein with various (e.g. angiogenic) activities. So far, research has focused on its angiogenic properties. VEGF receptors are localized on epithelial cells of patients with inflammatory bowel disease (IBD) and also on Caco-2 and IEC-18 cells. Our aim was to evaluate the role of VEGF on intestinal epithelial cell (IEC) migration and proliferation by utilizing an established in vitro model. Methods. IEC-18 and Caco-2 monolayers were wounded with a razor blade as described previously. Cells were incubated in medium w/o rat VEGF164. After 24 h, migration was assessed by counting cells across the wound edge. Migration was blocked with neutralizing TGF-β1 antibodies. IEC proliferation was assessed using the MTT (3-[4, 5-Dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide) test. Semi-quantitative changes of the TGF-β1 mRNA expression were evaluated before and after stimulation of the cells with VEGF164 by RT-PCR. Statistical analysis was performed with ANOVA and the Wilcoxon test. Results. VEGF164 significantly induced epithelial cell migration in Caco-2 and IEC-18 cells compared to control. TGF-β1 antibodies completely abolished this VEGF-induced cell migration. TGF-β1 mRNA significantly increased in IEC-18 and Caco-2 cells after stimulation with VEGF. VEGF significantly inhibited epithelial cell proliferation in IEC-18 and in Caco-2 cells, indicating that the observed effects on cell migration were not due to any proliferate effects. Conclusion. VEGF effects on epithelial cell migration play an important part in epithelial cell restitution by maintaining mucosal homeostasis after mucosal injury. This effect is mediated by TGF-β1. Our results obtain another possible role for increased VEGF levels in the intestinal mucosa of patients with IBD as reported recently by others.

Acquired pure megakaryocytic aplasia: a separate haematological disease entity or a syndrome with multiple causes?

We report the case of a patient with acquired pure megakaryocytic aplasia. Until today, less than 20 cases of acquired pure megakaryocytic aplasia have been reported and the disease aetiology still seems to be unclear. This report summarizes the published data concerning possible aetiologies, treatment options and outcome of patients with acquired pure megakaryocytic aplasia. Furthermore, this case report presents an example for a possible disease progression.

Tailored resective pancreatic surgery for pediatric patients with chronic pancreatitis

BACKGROUND Surgical treatment for chronic pancreatitis (CP) in children comprises predominantly nonresective draining procedures. The purpose of this study was to identify indications, techniques, and results of organ-preserving resective pancreatic procedures for pediatric CP at our institution. PATIENTS AND METHODS A retrospective chart review was performed of all children undergoing pancreatic surgery for CP over a period of 4 years. RESULTS Overall, 6 pediatric patients (3 male, 3 female, ages 7-18 years) underwent a duodenum-preserving pancreatic head resection (3), a middle segmental pancreatic resection (2), or a distal pancreatectomy (1) for CP of different etiologies (idiopathic 2, posttraumatic 2, pancreas divisum 1, situs inversus 1). No mortality or major surgical complication occurred. Mean operative time was 294 min (207-412 min) and intraoperative blood loss was 541 mL (100-1300 mL). Postoperative hospital stay was 13 days (10-18 days). No endocrine or exocrine insufficiency occurred during follow up of 46 months (25-50 m), and pain control was improved in 5 of 6 patients. CONCLUSIONS Tailored organ-preserving resective pancreatic surgery can be performed with low morbidity and mortality in pediatric patients with CP and not responding to conservative treatment.

Increased duodenal expression of transforming growth factor-α and epidermal growth factor during experimental colitis in rats

Objective/background Epidermal growth factor (EGF) and transforming growth factor alpha (TGF&agr;) protect gastrointestinal mucosa against injury. Having shown earlier, that TGF&agr; but not EGF is locally increasingly expressed after mucosal injury in the colon, we now wanted to explore the pattern of expression of EGF and TGF&agr; in the remaining gastrointestinal tract and to infer from the pattern of expression, to possible signals for the induction of the growth factor expression and further mechanisms for mucosal protection. Design/methods The trinitrobenzene sulfonic acid/ethanol-induced model of colitis in rats was used. TGF&agr;-mRNA and EGF-mRNA expression was evaluated in inflamed and noninflamed colon, in the ileum, jejunum, duodenum, stomach, and in the submandibulary glands. Results A significant increase of TGF&agr;-mRNA and EGF-mRNA expressions was detected in the duodenal mucosa and a significant increase in TGF&agr;-mRNA expression was observed in the inflamed colonic mucosa after mucosal injury in the colon within the first hours of colitis. Conclusion The increased expression of EGF and TGF&agr; in the duodenum may lead to neutralization of gastric acid and proteolytic enzymes in the upper gastrointestinal tract during the course of colitis. Possible signals for the increased expression of EGF and TGF&agr; presumably are fasting, parasympathetic, or adrenergic parts of the enteric nervous system or yet unknown mechanisms.