Daniel Bimmler

Pancreatic stone protein is highly increased during posttraumatic sepsis and activates neutrophil granulocytes.

Objectives:The level of pancreatic stone protein/regenerating protein (PSP/reg), a secretory protein produced in the pancreas, increases dramatically during pancreatic disease. However, after stress (e.g., anesthesia), PSP/reg levels are increased transiently in animals without pancreatic injury. Therefore, we aimed to determine whether PSP/reg is an acute-phase protein after nonpancreatic trauma. Patients:Eighty-three polytraumatic patients without pancreatic damage. Measurements and Main Results:We compared serum PSP/reg levels from polytraumatic patients without pancreatic damage with those in healthy controls (n = 38). C-reactive protein, interleukin-6, procalcitonin, and leukocyte numbers were also compared. The expression of CD62L and CD11b on neutrophils after exposure to PSP/reg was analyzed by flow cytometry. Thirty-three patients (39%) developed sepsis, 32 (38%) had local infections, and 18 (21%) had no infections. At admission, PSP/reg serum levels (10.2 [6.2–14.5] ng/mL; median [interquartile range]) were comparable with those in healthy controls (10.4 [7.5–12.3] ng/mL). During hospital stay, PSP/reg levels were elevated significantly in patients with sepsis (146.4 ng/mL) and in patients with infections (111.4 ng/mL) compared with patients without infections (22.8 ng/mL). Furthermore, binding of fluorescein isothiocyanate–labeled recombinant PSP/reg to human neutrophils was demonstrated. Recombinant PSP/reg elicited a dose-dependent shedding of L-selectin (CD62L) and upregulation of &bgr;2-integrin (CD11b) in neutrophils, which indicates that PSP/reg activates neutrophils. Conclusions:We conclude that PSP/reg is up-regulated in blood after trauma, and the PSP/reg level is related to the severity of inflammation. Furthermore, PSP/reg binds to and activates neutrophils. Therefore, PSP/reg might be an acute-phase protein that could serve as a marker for posttraumatic complications.

A selective COX-2 inhibitor suppresses chronic pancreatitis in an animal model (WBN/Kob rats): significant reduction of macrophage infiltration and fibrosis

Introduction: Therapeutic strategies to treat chronic pancreatitis (CP) are very limited. Other chronic inflammatory diseases can be successfully suppressed by selective cyclooxygenase 2 (COX-2) inhibitors. As COX-2 is elevated in CP, we attempted to inhibit COX-2 activity in an animal model of CP (WBN/Kob rat). We then analysed the effect of COX-2 inhibition on macrophages, important mediators of chronic inflammation. Methods: Male WBN/Kob rats were continuously fed the COX-2 inhibitor rofecoxib, starting at the age of seven weeks. Animals were sacrificed 2, 5, 9, 17, 29, 41, and 47 weeks later. In some animals, treatment was discontinued after 17 weeks, and animals were observed for another 24 weeks. Results: Compared with the spontaneous development of inflammatory injury and fibrosis in WBN/Kob control rats, animals treated with rofecoxib exhibited a significant reduction and delay (p<0.0001) in inflammation. Collagen and transforming growth factor β synthesis were significantly reduced. Similarly, prostaglandin E2 levels were markedly lower, indicating strong inhibition of COX-2 activity (p<0.003). If treatment was discontinued at 24 weeks of age, all parameters of inflammation strongly increased comparable with that in untreated rats. The correlation of initial infiltration with subsequent fibrosis led us to determine the effect of rofecoxib on macrophage migration. In chemotaxis experiments, macrophages became insensitive to the chemoattractant fMLP in the presence of rofecoxib. Conclusion: In the WBN/Kob rat, chronic inflammatory changes and subsequent fibrosis can be inhibited by rofecoxib. Initial events include infiltration of macrophages. Cell culture experiments indicate that migration of macrophages is COX-2 dependent.

Coordinate regulation of PSP/reg and PAP isoforms as a family of secretory stress proteins in an animal model of chronic pancreatitis.

BACKGROUND PSP/reg and PAP are secretory stress proteins (SSP) and may be part of a protective mechanism. They share structural homologies and form insoluble fibrils after tryptic activation. To further explore the regulation of these proteins, we investigated the male WBN/Kob rat, a model of pancreatic inflammatory and fibrotic disease similar to chronic pancreatitis. MATERIALS AND METHODS Expression of PSP/reg and PAP I, II and III in the WBN/Kob rat pancreas was evaluated on the mRNA and protein level, by immunohistochemistry and by highly sensitive isoform specific ELISAs. RESULTS The SSPs are constitutively secreted, PAP in nanomolar, PSP/reg in micromolar concentrations. Before conventional morphological changes are detectable in the WBN/Kob rat, focally increased expression of secretory stress protein is visible. SSP levels in pancreatic juice of WBN/Kob rats reach peak values 10- to 50-fold higher than in Wistar control rats. The highest expression was localized to acini with inflammatory infiltration. CONCLUSIONS There is a tight spatial and temporal association between pre-inflammatory changes or inflammation and SSP-expression. These results support our concept that PSP/reg and PAP are coordinately regulated SSP.

Increased secretion of the pancreatic secretory trypsin inhibitor (PSTI-I, monitor peptide) during development of chronic pancreatitis in the WBN/kob rat

Background: Recent genetic investigations into cationic trypsinogen and pancreatic secretory trypsin inhibitor (PSTI) led to the conclusion that mutations in either gene can contribute to the development of (hereditary) chronic pancreatitis. Since genetic animal models are not available yet, we have studied the Wistar-Bonn/Kobori (WBN/Kob) rat, a model for chronic pancreatitis (CP). To explore the possibility that PSTI may be secreted at lower levels or contain a mutation in the WBN/Kob rat, we investigated the masses of PSTI-I and -II and asked whether the ratio of PSTI/trypsinogen is decreased in animals with CP. Methods: We collected pancreatic juice from WBN/Kob and Wistar rats aged 6–36 weeks and measured PSTI-I (ELISA) and trypsin. Results: PSTI-I and -II were identified in Wistar and WBN/Kob rats by mass spectrometry and N-terminal sequencing. Using a newly developed PSTI-I ELISA, we can show that the PSTI-I/trypsinogen ratio is not decreased but rather increased in WBN/Kob rats compared to healthy Wistar rats. No evidence for a PSTI mutation was found. Conclusion: Our data does not support the hypothesis that a dysbalance of PSTI/trypsinogen ratio is a causative factor for CP.

The Bifunctional Rat Pancreatic Secretory Trypsin Inhibitor/Monitor Peptide Provides Protection against Premature Activation of Pancreatic Juice

Background: In the rat, two forms of the pancreatic secretory trypsin inhibitor, PSTI-I and PSTI-II, are secreted into pancreatic juice. It is assumed that their role is to protect the pancreas from premature activation of the protease-rich pancreatic juice. In the small intestine, PSTI-I, also called ‘monitor peptide’, is thought to have a different role: PSTI-I competes with protein for activated trypsin. In the presence of a protein-rich meal, free PSTI induces a release of cholecystokinine from the intestine. Methods: To investigate whether its role as monitor peptide is compatible with the inhibitory, protective function in the pancreas, PSTI-I was chemically synthesized and then renatured. Results: The peptide was almost completely trypsin resistant and exhibited a dose-dependent inhibitory activity to bovine and partially purified rat trypsin. Furthermore, experiments with trypsin- and endopeptidase-activated pancreatic juice demonstrated that its inhibitory capacity was sufficient to prevent premature activation. Binding studies of 125I-labeled PSTI-I with the putative intestinal receptor using isolated membranes indicated the presence of high-affinity binding sites (kd = 5 × 10–8M). Binding of PSTI-I could be competed with excess PSTI-I or trypsin. In a biological assay system, injections of PSTI-I displayed monitor peptide activity by inducing a dose-dependent trypsinogen release from the pancreas. Conclusion: Our experiments support a dual function of PSTI-I: monitoring protein in the gut due to its ‘moderate’ affinity for trypsin and a protective role in the pancreas.

The pancreas responds to remote damage and systemic stress by secretion of the pancreatic secretory proteins PSP/regI and PAP/regIII

Introduction In patients with infection and sepsis serum levels of Pancreatic Stone protein/regenerating protein I (PSP) are highly elevated. The origin of PSP during these conditions is presumably the pancreas, however, an intestinal origin cannot be excluded. Similarly, pancreatitis-associated protein (PAP) was identified in the pancreas. These proteins were also localized in intestinal organs. Here we aim to elucidate the bio-distribution of PSP and PAP in animal models of sepsis and in healthy humans. Results PSP and PAP responded to remote lesions in rats although the pancreatic response was much more pronounced than the intestinal. Tissue distribution of PSP demonstrated a 100-fold higher content in the pancreas compared to any other organ while PAP was most abundant in the small intestine. Both proteins responded to CLP or sham operation in the pancreas. PSP also increased in the intestine during CLP. The distribution of PSP and PAP in human tissue mirrored the distribution in the murine models. Materials and methods Distribution of PSP and PAP was visualized by immunohistochemistry. Rats and mice underwent midline laparotomies followed by mobilization of tissue and incision of the pancreatic duct or duodenum. Standard cecum-ligation-puncture (CLP) procedures or sham laparotomies were performed. Human tissue extracts were analyzed for PSP and PAP. Conclusions The pancreas reacts to remote lesions and septic insults in mice and rats with increased PSP synthesis, while PAP is selectively responsive to septic events. Furthermore, our results suggest that serum PSP in septic patients is predominantly derived through an acute phase response of the pancreas.