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Volker Keim

Publications and source records attributed to Volker Keim.

At least 19 recordsLinked to original sources
PubMed2006

Characterisation of a transgenic mouse expressing R122H human cationic trypsinogen.

BACKGROUND: The R122H mutation of the cationic trypsinogen was found in patients with hereditary pancreatitis. A transgenic animal carrying this mutation could be useful as a genetic model system of pancreatitis. METHODS: Mice transgenic for the human R122H cationic trypsinogen were generated using the -205 fragment of the rat elastase promoter. The presence of the transgene was assayed in the DNA, in pancreatic mRNA and in zymogen granule lysates. Serum levels of amylase, lipase and cytokines (MCP-1, IL-6) were monitored and the histological appearance of the tissue was investigated. Pancreatitis was induced by 7 hourly injections of 50 mug/kg cerulein. The procedure was repeated twice weekly for 10 consecutive weeks. The animals were sacrificed 24 (n = 8) and 48 hours (n = 8) after the first injection and at the end of the whole treatment (n = 7). RESULTS: The transgene was detected at the genomic level and in pancreatic mRNA. The corresponding protein was found in low amounts in zymogen granule lysates. R122H mice showed elevated pancreatic lipase, but there was no spontaneous development of pancreatitis within 18 months. After induction of pancreatitis, levels of lipase (after 24 hours) and amylase (after 48 hours) were higher in R122H mice compared to controls. Repeated treatment with cerulein resulted in a slightly more severe pancreatitis in R122H animals. Amylase, lipase, and the cytokine levels were similar to controls. CONCLUSION: The R122H transgenic mouse failed to develop a spontaneous pancreatitis but a repeatedly provoked cerulein-induced pancreatitis led to a slightly more severe pancreatitis. The rather small difference in comparison to controls could be due to the low expression of the transgene in the mouse pancreas.

Amylases↗
PubMed2006

A degradation-sensitive anionic trypsinogen (PRSS2) variant protects against chronic pancreatitis.

Chronic pancreatitis is a common inflammatory disease of the pancreas. Mutations in the genes encoding cationic trypsinogen (PRSS1) and the pancreatic secretory trypsin inhibitor (SPINK1) are associated with chronic pancreatitis. Because increased proteolytic activity owing to mutated PRSS1 enhances the risk for chronic pancreatitis, mutations in the gene encoding anionic trypsinogen (PRSS2) may also predispose to disease. Here we analyzed PRSS2 in individuals with chronic pancreatitis and controls and found, to our surprise, that a variant of codon 191 (G191R) is overrepresented in control subjects: G191R was present in 220/6,459 (3.4%) controls but in only 32/2,466 (1.3%) affected individuals (odds ratio 0.37; P = 1.1 x 10(-8)). Upon activation by enterokinase or trypsin, purified recombinant G191R protein showed a complete loss of trypsin activity owing to the introduction of a new tryptic cleavage site that renders the enzyme hypersensitive to autocatalytic proteolysis. In conclusion, the G191R variant of PRSS2 mitigates intrapancreatic trypsin activity and thereby protects against chronic pancreatitis.

Base Sequence↗
PubMed2005

Expression of mutated cationic trypsinogen reduces cellular viability in AR4-2J cells.

Mutations in the human cationic trypsinogen are associated with hereditary pancreatitis. The cDNA coding for human cationic trypsinogen was subcloned into the expression vector pcDNA3. The mutations R122H, N29I, A16V, D22G, and K23R were introduced by site directed mutagenesis. We constructed an expression vector coding for active trypsin by subcloning the cDNA of trypsin lacking the coding region for the trypsin activating peptide behind an appropriate signal peptide. Expression of protein was verified by Western blot and measurement of enzymatic activity. AR4-2J cells were transiently transfected with the different expression vectors and cell viability and intracellular caspase-3 activity were quantified. In contrast to wild-type trypsinogen, expression of active trypsin and mutated trypsinogens reduced cell viability of AR4-2J cells. Expression of trypsin and R122H trypsinogen induced caspase-3 activity. Acinar cells might react to intracellular trypsin activity by triggering apoptosis.

Animals↗
PubMed2005

The presence of the proteolysis-inducing factor in urine does not predict the malignancy of a pancreatic tumour.

BACKGROUND: The proteolysis-inducing factor (PIF) was identified as a tumour product in various gastrointestinal cancers. A previous study in pancreatic cancer patients suggested PIF expression as a tumour marker, which is not related to tumour size. We hypothesized that PIF could be a useful marker to exclude benign pancreatic tumors, as chronic pancreatitis with a pancreatic mass. METHODS: Urine of patients with a pancreatic mass of uncertain malignancy was investigated for PIF expression by Western blot. Sufficient urine protein for analysis was available in 59 patients. The diagnosis was established by histology in 54 patients and by follow up in five patients with chronic pancreatitis. In addition, serum CA19-9 was measured. RESULTS: The sensitivity (specifity) for the detection of a malignant pancreatic tumour was 90% (75%) and 54% (71%) for CA19-9 and PIF, respectively. The sensitivity (specifity) for the distinction of pancreatic cancer from chronic pancreatitis was 89% (80%) and 57% (63%) for CA19-9 and PIF, respectively. CONCLUSION: Evaluation of PIF in urine is of no diagnostic value in patients with a pancreatic mass of unknown malignancy.

Adult↗
PubMed2005

Transforming growth factor-beta-1 variants are not associated with chronic nonalcoholic pancreatitis.

BACKGROUND: Pancreatic fibrosis is a key pathological feature of chronic pancreatitis. In vivo and in vitro data have demonstrated that pancreatic stellate cells (PSC) play a central role in pancreatic fibrosis. PSC activation and collagen synthesis are highly controlled by transforming growth factor-beta-1 (TGF-beta1). We evaluated whether functionally relevant genetic variants of TGF-beta1 are associated with chronic nonalcoholic pancreatitis. METHODS: The promotor as well as exon 1 variants of the TGF-beta1 gene (G-800A, Leu10Pro and Arg25Pro) were investigated. Forty-two CP patients with a family history of nonalcoholic chronic pancreatitis (group A) and 88 patients without a family history of nonalcoholic chronic pancreatitis (group B) were studied. One hundred blood donors served as controls (group C). RESULTS: The allelic frequencies of G-800A, Leu10Pro and Arg25Pro were 12, 38 and 6% in group A; 7, 40 and 6% in group B and 12, 29 and 3% in group C, respectively. The differences were not significant. CONCLUSION: Functionally relevant genetic variants of the TGF-beta1 gene are not associated with nonalcoholic chronic pancreatitis.

Adolescent↗
PubMed2005

Gene conversion between functional trypsinogen genes PRSS1 and PRSS2 associated with chronic pancreatitis in a six-year-old girl.

Gene conversion--the substitution of genetic material from another gene--is recognized as the underlying cause of a growing number of genetic diseases. While in most cases conversion takes place between a normal gene and its pseudogene, here we report an occurrence of disease-associated gene conversion between two functional genes. Chronic pancreatitis in childhood is frequently associated with mutations of the cationic trypsinogen gene (serine protease 1; PRSS1). We have analyzed PRSS1 in 1106 patients with chronic pancreatitis, and identified a novel conversion event affecting exon 2 and the subsequent intron. The recombination replaced at least 289 nucleotides with the paralogous sequence from the anionic trypsinogen gene (serine protease 2; PRSS2), and resulted in the PRSS1 mutations c.86A > T and c.161A > G, causing the amino acid substitutions N29I and N54S, respectively. Analysis of the recombinant N29I-N54S double mutant cationic trypsinogen revealed increased autocatalytic activation, which was solely due to the N29I mutation. In conclusion, we have demonstrated that gene conversion between two functional paralogous trypsinogen genes can occur and cause genetically determined chronic pancreatitis.

Adolescent↗
PubMed2004

Interaction between trypsinogen isoforms in genetically determined pancreatitis: mutation E79K in cationic trypsin (PRSS1) causes increased transactivation of anionic trypsinogen (PRSS2).

The human pancreas secretes two major trypsinogen isoforms, cationic and anionic trypsinogen. To date, 19 genetic variants have been identified in the cationic trypsinogen gene (PRSS1) of patients with hereditary, familial, or sporadic chronic pancreatitis. A common feature of cationic trypsinogen mutants studied so far is an increased propensity for autocatalytic activation (autoactivation). This is thought to lead to premature intrapancreatic digestive protease activation. In contrast, no pancreatitis-associated mutations have been found in the anionic trypsinogen gene (PRSS2), suggesting that this isoform might play a relatively unimportant role in pancreatitis. To challenge this notion, here we describe the unique properties of the E79K cationic trypsinogen mutation (c.235G>A), which was identified in three European families affected by sporadic or familial pancreatitis cases. In vitro analysis of recombinant wild-type and mutant enzymes revealed that catalytic activity of E79K trypsin was normal, and its inhibition by pancreatic secretory trypsin inhibitor was unaffected. Although the E79K mutation introduces a potential new tryptic cleavage site, autocatalytic degradation (autolysis) of E79K-trypsin was also unchanged. Furthermore, in contrast to previously characterized disease-causing mutations, E79K markedly inhibited autoactivation of cationic trypsinogen. Remarkably, however, E79K trypsin activated anionic trypsinogen two-fold better than wild-type cationic trypsin did, while the common pancreatitis-associated mutants R122H or N29I had no such effect. The observations not only suggest a novel mechanism of action for pancreatitis-associated trypsinogen mutations, but also highlight the importance of interactions between the two major trypsinogen isoforms in the development of genetically determined chronic pancreatitis.

Adult↗
PubMed2004

Pseudomonas pneumonia-mediated sepsis induces expression of pancreatitis-associated protein-I in rat pancreas.

Severe impairment of exocrine pancreatic secretion has recently been demonstrated in a clinical study in sepsis and septic shock patients. The purpose of this study was to further evaluate involvement of the pancreas in the acute phase reaction in sepsis. Using a normotensive rat model of Pseudomonas pneumonia-induced sepsis, we assessed the expression of PAP-I, amylase and trypsinogen mRNA, PAPI protein levels, and cytokine expression in the pancreas by Northern and Western blot analysis and RT-M PCR, respectively. Presence of several well-established features of pancreatitis in sepsis-induced animals were examined by biochemical and histopathological methods as well as by a determination of both water and myeloperoxidase content. Sepsis resulted in an up-regulation of PAP-I gene expression and increase in its protein level in pancreas while the mRNA levels of amylase and trypsinogen were down-regulated. Differences in the pancreatic cytokine expression, serum amylase and serum lipase levels, the occurrence of pancreatic edema as well as the severity of inflammatory infiltration and necrosis were not significantly different between sham and pneumonia groups. Acinar cells showed increased vacuolization in pneumonia animals 24 hours after the treatment. These findings demonstrate that the pancreas is actively involved in the acute phase reaction in sepsis of remote origin. This involvement occurs without concomitant biochemical and histopathologic alterations observed in pancreatitis. Taken all together, these features are indicative of a sepsis-specific dysfunction of the pancreas.

Acute-Phase Reaction↗
PubMed2004

Chronic parotitis: not another SPINKosis.

INTRODUCTION: Pancreatitis and parotitis share several etiological, pathohistological and functional similarities. It arose from recent pancreatitis research that some cases of chronic pancreatitis are associated with mutations of the serine protease inhibitor, Kazal type-1 (SPINK1). We tested the hypothesis that the pancreatitis-associated N34S mutation of SPINK1 is also a risk factor for chronic parotitis. METHODS: Reverse-transcriptase polymerase chain reaction was used to investigate SPINK1 transcription in the parotid gland. Forty-five blocks of formalin-fixed, paraffin wax-embedded tissues with chronic parotitis of unknown cause were analyzed for the SPINK1-N34S mutation. RESULTS: The SPINK1 gene is transcribed in the parotid gland. Two of the 45 patients (4.4%) with chronic parotitis carried the N34S mutation heterozygously. Of 82 healthy blood donors, 3 subjects (3.7%) were identified as carrying this mutation heterozygously (p = 0.83). CONCLUSION: The SPINK1-N34S mutation is not associated with chronic parotitis.

Carrier Proteins↗
PubMed2003

Evaluation of Pankrin, a new serum test for diagnosis of acute pancreatitis.

AIM: Evaluation of a new serum test for diagnosis of acute pancreatitis. PATIENTS AND METHODS: One hundred and sixty-three patients presenting with acute abdominal pain were included into the study. Acute pancreatitis was diagnosed by CT or ultrasound. Serum samples were taken 0-1 days, 2-3 days, and 4-5 days after onset of symptoms and C-reactive protein, lipase, elastase, and amylase were determined. As a further parameter, Pankrin, a newly available kit for the measurement of a mixture of elastase and other pancreatic secretory proteins was used. As control, serum from 558 apparently healthy blood donors was analysed. The receiver operator characteristics (ROC) and the areas under the curves (AUC) were calculated for each individual test. RESULTS: In Western blot analysis the antibodies of the Pankrin assay detected the majority of protein bands in human pancreatic juice. In blood donors, the median value of Pankrin was 88 U/ml (range 14-316 U/ml). In 16 from 163 patients with acute abdominal pain, acute pancreatitis was diagnosed and the median Pankrin level in samples collected on days 0-1 was 345 U/ml (range 220-518 U/ml, p<0.0001). In those patients with abdominal pain but without pancreatitis, the median was 116 U/ml (range 17-396 U/ml). The ROC-curves for amylase, lipase, elastase, and Pankrin from samples collected after 0-1 days were similar (area under the curves (AUC) >0.98). After 2-3 days, the AUC of all markers decreased (AUC 0.80-0.89) and after 4-5 days the AUC of Pankrin (0.85) was higher than all other parameters. CONCLUSION: In those patients with abdominal pain, who present several days after onset of pain, the new serum test for pancreatitis, Pankrin, could be of help to improve the diagnosis of pancreatitis.

Abdomen, Acute↗
PubMed2003

UDP glucuronosyltransferase (UGT1A7) gene polymorphisms increase the risk of chronic pancreatitis and pancreatic cancer.

BACKGROUND & AIMS: Chronic pancreatitis and pancreatic adenocarcinoma are associated with alcohol abuse, consumption of tobacco smoke, and environmental aromatic hydrocarbon exposure. The role of genetic factors is incompletely defined. Uridine 5'-diphosphate glucuronosyltransferases are phase II detoxifying enzymes capable of tobacco-borne toxicant inactivation and cellular protection. This study analyzes UGT1A7 gene polymorphisms in pancreatic diseases. METHODS: Genomic DNA from northern German white patients with pancreatic adenocarcinoma (n = 52) and chronic pancreatitis (n = 146), as well as healthy blood donors (n = 235) was analyzed by UGT1A7-specific PCR, sequencing analysis, and temperature gradient gel electrophoresis. Pancreatic expression of UGT1A genes was identified by duplex reverse-transcription PCR. RESULTS: Predominant expression of the UGT1A7 gene was identified in human pancreatic tissue. Pancreatic adenocarcinoma was associated with the low detoxification activity UGT1A7*3 allele, which combines the W208R, N129K, and R131K mutations (odds ratio [OR], 1.98; 95% confidence interval [CI ], 1.24-3.14; P = 0.003). The association of UGT1A7*3 was especially strong in smokers with pancreatic carcinoma who were younger than 55 years (OR, 4.7; 95% CI, 1.9-11.8; P = 0.0009). Chronic pancreatitis was also associated with UGT1A7*3 (OR, 1.76; 95% CI, 1.26-2.46; P = 0.0009). UGT1A7*3 was specifically associated with the subgroup of patients with alcoholic pancreatitis, of whom 89% were smokers (OR, 2.24; 95% CI, 1.46-3.43; P = 0.0001) but was not associated with the nonalcoholic pancreatitis subgroup. CONCLUSIONS: The UGT1A7 gene is predominantly expressed in human pancreas. The low detoxification activity UGT1A7*3 allele is identified as a novel risk factor of pancreatic diseases defining the interaction of genetic predisposition and environmentally induced oxidative injury.

Adenocarcinoma↗
PubMed2003

Outcome after duodenum-preserving pancreatic head resection is improved compared with classic Whipple procedure in the treatment of chronic pancreatitis.

BACKGROUND: There is no consensus in the surgical management of chronic pancreatitis (cP) as to whether techniques preserving the duodenum are superior to pancreatoduodenectomy. This prospective study compared the outcome of standard pancreatoduodenectomy (PD) and duodenum-preserving pancreatic head resection (DPPHR) in treatment of selected patients with cP. METHODS: Inclusion criteria for this prospective controlled, nonrandomized study were patients suffering from cP centered in the head and with severe pain. Seventy consecutive patients underwent DPPHR (n = 38) or, if there was suspicion of malignancy, classic PD (n = 32). A multidimensional, psychometric questionnaire was used to measure the quality of life (QoL). QoL was compared with that of the general German population. Pain intensity was evaluated on the basis of the frequency of pain attacks, analgesic medication, and self-assessed pain score. Assessment of endocrine and exocrine function as well as nutritional status included oral glucose tolerance test, fecal elastase, stool frequency, and body mass index. The median follow-up was 34 months. RESULTS: Multiple clinical characteristics did not differ between the two groups except for age (P =.04), the tumor marker carbohydrate antigen 19-9 (P =.02), and the parameter suspicion of malignancy. There was no hospital mortality. Surgical morbidity was 19% in the PD group and 8% in the DPPHR group (P =.60). PD resulted in a longer median hospital stay than DPPHR (19 vs 15 days, P =.04). Complications of adjacent organs were definitively treated in 100% after PD and in 97% after DPPHR. Postoperative pain intensity as self-assessed by the patients was significantly less in the DPPHR group (P <.001), whereas the frequency of acute episodes (P =.27) and analgesic medication (P =.43) did not differ between the two groups. After surgery, symptom and functional scales of the DPPHR group were significantly better than those in the PD group and were similar to those of the overall German population. No significant difference was found between the two groups with regard to endocrine and exocrine function. Postoperative increase of body mass index was significantly higher in the DPPHR group (P <.001). CONCLUSIONS: DPPHR provides better results in the treatment of cP than PD in terms of QoL, pain intensity as self-assessed by the patients, nutritional status, and length of hospital stay.

Adult↗