Correlation among complement activation, protease inhibitors, and clinical course in acute pancreatitis in man

The early predictive role of complement C3 and C4 in patients with acute pancreatitis

Objective

The prognostic role of complement C3 and C4 in peripheral blood in early stage of acute pancreatitis (AP) is unknown. In this study, we aimed to evaluate the prognostic value of C3 and C4 in early stage of AP.

Methods

A total of 164 patients were enrolled in this study. The blood samples were collected within 24 hours after AP onset. We compared C3 and C4 levels in patients with different AP severity. The optimal cutoff value for them to predict severe AP (SAP) was determined by receiver operating characteristic (ROC) curve analysis.

Results

The reduction of C3 and C4 levels was observed. For prediction of MSAP and SAP, the AUC of C3 and C4 levels was 0.695 (95% CI: 0.612‐0.779) and 0.739 (95% CI: 0.657‐0.821). The cutoff value of C3 and C4 levels was 0.705 and 0.145 g/L, with the sensitivity of 0.612 and 0.735, and the specificity of 0.735 and 0.710. For prediction of SAP, the AUC of C3 and C4 levels was 0.749 (95% CI: 0.607‐0.891) and 0.766 (95% CI: 0.596‐0.936). The cutoff value of C3 and C4 levels was 0.400 and 0.125 g/L, with the sensitivity of 0.859 and 0.767, and the specificity of 0.600 and 0.786.

Conclusions

A marked change of complement C3 and C4 was observed in peripheral blood of patients with AP, suggesting the participation of complement system in the early phase of AP. C3 and C4 levels were sensitive and accurate in judging the severity of AP.

Complement in Pancreatic Disease-Perpetrator or Savior?

The complement system is a major pillar of the humoral innate immune system. As a first line of defense against pathogens, it mediates early inflammatory response and links different branches of humoral and cellular immunity. Disorders affecting the exocrine pancreas, such as acute pancreatitis, potentially lead to a life-threatening systemic inflammatory response with aberrant activation of complement and coagulation cascades. Pancreatic proteases can activate key effectors of the complement system, which in turn drive local and systemic inflammation. Beyond that, the extent of pancreas–complement interaction covers complex pro- and anti-inflammatory mechanisms, which to this day remain to be fully elucidated. This review provides a comprehensive overview of the pathophysiological role of complement in diseases of the exocrine pancreas, based on existing experimental and clinical data. Participation of complement in acute and chronic pancreatitis is addressed, as well as its role in tumor immunology. Therapeutic strategies targeting complement in these diseases have long been proposed but have not yet arrived in the clinical setting.

Complement Component 5 Mediates Development of Fibrosis, via Activation of Stellate Cells, in 2 Mouse Models of Chronic Pancreatitis

BACKGROUND & AIMS

Little is known about the pathogenic mechanisms of chronic pancreatitis. We investigated the roles of complement component 5 (C5) in pancreatic fibrogenesis in mice and patients.

METHODS

Chronic pancreatitis was induced by ligation of the midpancreatic duct, followed by a single supramaximal intraperitoneal injection of cerulein, in C57Bl6 (control) and C5-deficient mice. Some mice were given injections of 2 different antagonists of the receptor for C5a over 21 days. In a separate model, mice were given injections of cerulein for 10 weeks to induce chronic pancreatitis. Direct effects of C5 were studied in cultured primary cells. We performed genotype analysis for the single-nucleotide polymorphisms rs 17611 and rs 2300929 in C5 in patients with pancreatitis and healthy individuals (controls). Blood cells from 976 subjects were analyzed by transcriptional profiling.

RESULTS

During the initial phase of pancreatitis, levels of pancreatic damage were similar between C5-deficient and control mice. During later stages of pancreatitis, C5-deficient mice and mice given injections of C5a-receptor antagonists developed significantly less pancreatic fibrosis than control mice. Primary pancreatic stellate cells were activated in vitro by C5a. There were no differences in the rs 2300929 SNP between subjects with or without pancreatitis, but the minor allele rs17611 was associated with a significant increase in levels of C5 in whole blood.

CONCLUSIONS

In mice, loss of C5 or injection of a C5a-receptor antagonist significantly reduced the level of fibrosis of chronic pancreatitis, but this was not a consequence of milder disease in early stages of pancreatitis. C5 might be a therapeutic target for chronic pancreatitis.

Treating acute pancreatitis: what's new?

The medical treatment of acute pancreatitis continues to focus on supportive care, including fluid therapy, nutrition, and antibiotics, all of which will be critically reviewed. Pharmacologic agents that were previously studied were found to be ineffective likely due to a combination of their targets and flaws in trial design. Potential future pharmacologic agents, particularly those that target intracellular calcium signaling, as well as considerations for trial design will be discussed. As the incidence of acute pancreatitis continues to increase, greater efforts will be needed to prevent hospitalization, readmission and excessive imaging in order to reduce overall healthcare costs. Primary prevention continues to focus on post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis and secondary prevention on cholecystectomy for biliary pancreatitis as well as alcohol and smoking abstinence.

Immunosuppression in patients with severe acute pancreatitis

BACKGROUND

In severe acute pancreatitis (SAP), immunologic impairment in the early phase may be linked to subsequent infectious complications. In this study, immunologic alterations in patients with SAP were analyzed, and immunologic parameters related to infectious complications were clarified.

METHODS

A total of 101 patients with SAP were analyzed retrospectively. Various immunologic parameters on admission were analyzed and compared between the infection group and noninfection group during SAP. Furthermore, chronologic change in the lymphocyte count was investigated, and its utility for predicting infection was compared with conventional scoring systems.

RESULTS

Serum immunoglobulin G (IgG), serum IgM, lymphokine-activated killer cell activity, and natural killer cell activity were low, and the incidence of abnormally low values was 50.0%, 65.0%, 45.5%, and 42.4%, respectively. Serum complement factor 3 was significantly negatively correlated with the APACHE II score. The lymphocyte count was decreased below the normal range, and was significantly negatively correlated with the APACHE II score. CD4-, CD8-, and CD20-positive lymphocyte counts were below the normal range, and CD4- and CD8-positive lymphocyte counts were significantly lower in the infection group. The lymphocyte count on day 14 after admission was significantly lower in the infection group and was more useful for predicting infection than conventional scoring systems.

CONCLUSIONS

Immunosuppression occurs from the early phase in SAP, and quantitative impairment of lymphocytes, mainly T lymphocytes, may be closely related to infectious complications during SAP. CD4- and CD8-positive lymphocyte counts on admission and the lymphocyte count on day 14 after admission may be useful for predicting infection.

Pancreas graft thrombosis: is there a role for trypsin

PURPOSE

Thrombosis of the pancreas graft is the main cause of early graft loss in pancreas transplantation. We investigated whether hypercoagulability develops locally in the pancreas and contributes to thrombosis formation because of ischemia or reperfusion injury. It was further hypothesized that this might be induced by excessive intravascular trypsin activity.

METHODS

Ten Patients undergoing pancreas transplantation were studied. In addition to the standard operation a 14 French catheter was inserted in the distal part of the splenic vein of the pancreas graft. After reperfusion blood samples were drawn simultaneously from the splenic vein of the pancreas graft (local samples) and the radial artery (systemic samples) at 0,1,2,5,10,30, and 60 minutes after reperfusion.

RESULTS

After reperfusion a progressive hypercoagulability developed locally in the pancreas as seen by an increase of thrombin-antithrombin complexes and only a transient increase of plasmin-antiplasmin complexes. In addition antithrombin 3 and protein c decreased systemically. The alterations seem not to be triggered by trypsin because trypsin activity locally remained low despite trypsinogen release and activation as assessed by trypsinogen activation peptides.

CONCLUSION

Local hypercoagulability might contribute to the development of graft thrombosis, however, the mechanism seems not to be related to ectopic trypsin activation.

Immune function early in acute pancreatitis

Circulating lymphocyte numbers and activation together with granulocyte function were measured in 20 patients in the early stages of an attack of acute pancreatitis and in 20 healthy controls. Circulating lymphocytes, T lymphocytes, and CD4 and CD8 T lymphocyte subsets were decreased in both mild pancreatitis (67-80 per cent of controls) and severe pancreatitis (22-40 per cent of controls). CD4:CD8 ratios were unchanged and median (interquartile range) interleukin 2 receptor expression was increased from less than 1 per cent in controls to 14(6) per cent in severe pancreatitis, suggesting lymphocyte activation. Median granulocyte chemiluminescence was increased to 293 per cent of controls in severe pancreatitis and random motility was reduced to 77 per cent of controls, indicating increased metabolic activity. Complement-mediated antibody-independent opsonization and chemotaxis toward endotoxin were normal. Immune function is not reduced early in acute pancreatitis. Granulocyte hyperactivity may be important in the development of multiple organ failure.

Complement inhibition by soluble complement receptor type 1 fails to moderate cerulein-induced pancreatitis in the rat

CONCLUSION

Cerulein-induced pancreatitis in rats associated with remote liver and lung dysfunction. Soluble complement receptor 1 (sCR1) does not reduce the local or remote injury. Thus complement activation does not moderate cerulein-induced pancreatitis or the associated liver and injury.

BACKGROUND

The local and remote injury of pancreatitis resembles other inflammatory events that are mediated by complement. This study examines the effect of complement inhibition with sCR1 in cerulein-induced pancreatitis in rats.

METHODS

Thirteen Sprague-Dawley rats received five hourly subcutaneous doses of cerulein (100 micrograms initially, then 50 micrograms/kg). Six of these animals received hourly i.v. sCR1 (15 mg/kg, a proven complement-inhibiting dose in rats) and the other seven received i.v. saline. In parallel, 12 additional rats received hourly s.c. and i.v. saline.

RESULTS

Compared to saline controls, rats receiving cerulein showed increased pancreatic wet-to-dry ratio (3.25:8.52), hematocrit (40 to 47%), ascites volume (2.1 to 6.1 mL), serum amylase (1680 to 10,700 U/L), and ascites amylase (32,200 to 167,000 U/L) (all p < 0.05). None of these parameters were modified by treatment with sCR1. Serum SGPT, which increased from 33.4 to 46.6 U/L in cerulein-infused rats, showed a trend toward reduction to 38.8 U/L in rats treated with sCR1. Cerulein-treated rats also had increased lung myeloperoxidase (0.069 to 0.097 U/g) and lung permeability, as assessed by a alveolar lavage to serum ratio of labeled albumen (0.041:0.121) both p < 0.05). Neither were changed by sCR1 treatment.

Effects of C1-esterase inhibitor in three models of acute pancreatitis

The present studies were done to evaluate the therapeutic potential of C1-esterase inhibitor in three different models of acute pancreatitis: (1) Edematous pancreatitis with acinar cell necrosis was induced by 7-h ip injections of 50 micrograms/kg cerulein in mice; (2) Hemorrhagic pancreatitis was induced by feeding a choline-deficient, ethionine-supplemented (CDE) diet in mice; and (3) Hemorrhagic pancreatitis was induced by retrograde infusion of 0.6 mL 5% sodium-taurocholate into the pancreatic duct in rats. C1-esterase inhibitor was given at 100 mg/kg iv before the onset of pancreatitis and at certain intervals thereafter. The severity of pancreatitis was assessed at various times after its onset by determination of serum amylase, by grading of histological alterations, and by determination of survival (survival determined only in models of hemorrhagic pancreatitis). In some of the models, C1-esterase inhibitor slightly ameliorated the degree of histological alterations; the increase in serum amylase was reduced by C1-esterase inhibitor only in CDE diet-induced pancreatitis. In all three models, C1-esterase inhibitor, however, failed to cause major beneficial effects and also failed to improve survival in taurocholate- and diet-induced pancreatitis. Additional studies in 12 patients with acute pancreatitis showed that C1-esterase inhibitor activity was markedly increased in serum of all patients during the first 9 d of the disease, suggesting that C1-esterase inhibitor behaves like an acute phase protein. Taken together the results from the animal and the human studies, C1-esterase inhibitor appears to only have a limited potential for treatment of acute pancreatitis.

Monitoring of serum proteinase--antiproteinase balance and systemic inflammatory response in prognostic evaluation of acute pancreatitis. Results of a prospective multicenter study

With the aim of studying the clinical usefulness and applicability of circulating levels of protease inhibitors, complement factors, acute phase reactants, and leukocytic enzymes in the prognostic evaluation of acute pancreatitis (AP), the present prospective multicenter study has been carried out. A total of 182 patients with AP have been included, to whom an exhaustive evolutive protocol has been applied from the time of their hospital admission (2-12 hr from the onset of the disease) until the 15th day of evolution in order to clearly define them. The severe episodes exhibit a greater consumption of alpha 2-macroglobulin, and C3 and C4 complement factors, as well as a greater increase of alpha 1-protease inhibitor, C-reactive protein and polymorphonuclear elastase than mild events, with regards to the underlying pathophysiological condition. The determination of the plasma levels of leukocytic elastase in the first hours of evolution allows a prediction of the severity of the acute pancreatitis event with a high reliability (predictive values that become higher than 90%). The clinical value of the remaining parameters analyzed, in this aspect, is less, being applicable to the monitoring of the disease.

Impaired mononuclear phagocyte function in patients with severe acute pancreatitis: evidence from studies of plasma clearance of trypsin and monocyte phagocytosis

Activated proteases in plasma are complexed by alpha 2-macroglobulin. Although the complexes retain peptidase activity, they are usually eliminated promptly by mononuclear phagocytes. In severe acute pancreatitis, almost 30% of plasma alpha 2-macroglobulin becomes complexed, suggesting impaired clearance. In the present study, plasma [methyl-14C]trypsin clearance and monocyte phagocytosis were investigated. Attacks complicated by major organ-system failure, pancreatic pseudocyst, abscess, or necrosis were graded severe (median Ranson score 5.5). Plasma [methyl-14C]trypsin half-life was significantly increased in severe attacks (N = 7, median 21.1 min), compared to mild attacks (N = 14, median 15.4 min, P < 0.05) and healthy controls (N = 4, median 10.8 min, P < 0.02). Monocyte phagocytosis was significantly lower in severe attacks (N = 9, median 3.6%) compared to mild attacks (N = 20, median 20.8%, P < 0.01) and healthy controls (N = 8, median 26.9%, P < 0.01). Plasma [methyl-14C]trypsin half-life and monocyte phagocytosis were significantly inversely correlated (r = -0.51, P < 0.01). Impaired clearance of circulating trypsin in acute pancreatitis is potentially deleterious but may be reversed by stimulating mononuclear phagocytes.

Alpha-2-macroglobulin decreases parallel to albumin and haemoglobin after elective surgery

Plasma levels of the plasma protease inhibitor alpha-2-macroglobulin (alpha 2-M) were followed for 7 days in 90 patients subjected to various surgical procedures. Alpha 2-M was found to decrease strictly in parallel with the decrease seen for haemoglobin and albumin levels in all patients. Changes were most pronounced after extensive operations; total hip replacement (n = 7), pulmonary resection (n = 11), extensive colo-rectal resection (n = 15), and less pronounced after 'minor' operations; mastectomy (n = 23) proximal gastric vagotomy (n = 5) and moderate colo-rectal resection (n = 29). Levels were lowest on the second to third postoperative day, whereafter they slowly returned to normal, preoperative levels during the 7-day study period. Functional and quantitative alpha 2-M levels almost paralleled each other throughout the 7 days studied. Chromogenic peptide substrate assays indicated circulating plasmin-alpha 2-M complexes, while no protease-alpha 2-M complexes could be demonstrated using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) or isoelectric focusing (IEF) analyses. Local accumulation and consumption of proteins within wounded tissues, together with haemodilution, were probably the major factors responsible for the decreased plasma levels seen. It is concluded that the plasma levels of alpha 2-M decrease after major elective surgery strictly in parallel with the decrease seen in haemoglobin and albumin levels, and that circulating plasmin-alpha 2-M complexes are probable. The decrease seems to be graded, that is, proportional to the extent of the operative trauma, similar to the postoperative increase seen in positive acute-phase proteins. Thus, alpha 2-M cannot be used as an internal, unchanged plasma protein standard for other protein changes seen after trauma.

Granulocyte elastase in assessment of severity of acute pancreatitis. Comparison with acute-phase proteins C-reactive protein, alpha 1-antitrypsin, and protease inhibitor alpha 2-macroglobulin

Complexes of granulocyte elastase and alpha 1-antitrypsin are markers for granulocyte activation. In 75 patients with acute pancreatitis these complexes were immunologically determined daily in plasma during the first week of hospitalization. Patients were classified into three groups: mild pancreatitis (I, less than or equal to 1 complication, N = 34), severe pancreatitis (II, greater than or equal to 2 complications, N = 29), lethal outcome (III, N = 12). Initially, granulocyte elastase (mean +/- SEM) was lower in group I (348 +/- 39 micrograms/liter) as compared to groups II (897 +/- 183 micrograms/l) and III (799 +/- 244 micrograms/liter), P less than 0.001 for I vs II + III. Initial elastase concentrations greater than 400 micrograms/liter were consistent with a severe or fatal course of the disease but did not distinguish between severe and lethal pancreatitis. In patients with mild or severe disease, mean elastase concentrations decreased continuously during the following days (197 +/- 15 micrograms/liter in mild cases, 325 +/- 30 micrograms/liter in severe cases at day 7). In patients with lethal disease, however, mean elastase concentrations even increased at day 2 and remained higher than 700 micrograms/liter during the observation period. At days 1 and 2 the predictive value for severe or lethal disease of raised (greater than 400 micrograms/liter) elastase concentrations [positive predictive value (PPV) 82%, negative predictive value (NPV) 81%] was better than that of elevated (greater than 100 mg/liter) C-reactive protein (PPV 73%, NPV 73%), elevated (greater than 4.0 g/liter) alpha 1-antitrypsin (PPV 59%, NPV 50%), or decreased (less than 1.5 g/liter) alpha 2-macroglobulin (PPV 82%, NPV 67%).(ABSTRACT TRUNCATED AT 250 WORDS)

Local administration of human pancreatic secretory trypsin inhibitor prevents the development of experimental acute pancreatitis in rats and dogs

The objective of this investigation was to test the capacity of recombinant human pancreatic secretory trypsin inhibitor (rhPSTI) to provide prophylaxis against experimental pancreatitis. Acute hemorrhagic pancreatitis was induced by intraductal injection of sodium taurocholate in rats and by intraductal injection of bile in dogs. In one treatment group of rats the injection of taurocholate was preceded by injection of rhPSTI. In a second group of rats the rhPSTI was given intraperitoneally starting 15 min after the induction of acute pancreatitis. The survival rate in a control group of rats was 13%. In contrast, the survival rate in groups receiving rhPSTI intraductally or intraperitoneally was 80% and 63%, respectively. The survival rate in a control group of dogs was 40% at 24 h and 0% at 48 h. In contrast, all the dogs receiving a single intraductal dose of rhPSTI, either immediately before the bile injection or mixed with the bile, survived for up to 6 weeks. Detailed biochemical and immunohistologic studies in the dog indicate that, whereas rhPSTI cannot prevent the initial bile-induced injury, it does prevent the subsequent development of that injury to the point where there is massive damage to the pancreas and the surrounding tissues, and changes in blood chemistry. The development of the initial injury is, therefore, presumed to involve activation of trypsinogen. Since rhPSTI prevents the serious consequences of experimental pancreatic injury by blocking the action of trypsin, and since the pathobiochemistry of human acute pancreatitis also implies an important role for trypsin, it is possible that rhPSTI could protect humans from the pancreatitis that complicates endoscopic retrograde cholangiopancreatography and endoscopic papillotomy.

Long-term ethanol ingestion does not increase the toxicity of peritoneal exudate generated during acute haemorrhagic pancreatitis in rats

Thirty male Wistar rats were randomly divided into two groups. One group received 15% (vol/vol) ethanol as their only drinking solution for 12 weeks; the rest of the animals served as controls, receiving tap water only. Acute haemorrhagic pancreatitis (AHP) was induced with a retrograde infusion of 5% sodium taurocholate into the pancreatic ducts, and the generated peritoneal exudate was collected 5 h after induction. When compared with the water-receiving control rats, chronic ethanol ingestion decreased amylase activity (p less than 0.001) and trypsin-inhibiting capacity (TIC) (p less than 0.001), whereas protein concentration was increased (p less than 0.001) in the peritoneal exudate collected from the ethanol-receiving group. The toxicity of the peritoneal exudate was assessed by intraperitoneal injections of the exudate from rats into mice (n = 90). Saline or injections of the peritoneal exudate from the rats that received water did not kill any mice, and exudate from the rats that had been drinking the mixture of ethanol and water killed one mouse. In conclusion, chronic ethanol ingestion does not increase the toxicity of the peritoneal exudate secreted during AHP in this experimental model. In AHP, however, ethanol consumption increases protein concentration and decreases TIC in peritoneal exudate. Hence, the balance of the protease-antiprotease system may be of importance to the outcome of AHP.

Repression of alpha 2-macroglobulin and stimulation of alpha 1-proteinase inhibitor synthesis in human mononuclear phagocytes by endotoxin

Mononuclear phagocytes are a bone-marrow-derived subgroup of white blood cells which circulate as monocytes and, after differentiation into macrophages, become resident in many tissues. By synthesizing the important proteinase inhibitors alpha 2-macroglobulin and alpha 1-proteinase inhibitor mononuclear phagocytes contribute to the control of proteolysis both in blood and tissues. Applying a culture system which enables human blood monocytes to differentiate into macrophages in vitro, synthesis of alpha 2-macroglobulin and alpha 1-proteinase inhibitor was studied. The normal course of monocyte-macrophage maturation is accompanied by a strong increase of specific alpha 2-macroglobulin synthesis and a concomitant slight decrease of alpha 1-proteinase inhibitor. alpha 2-Macroglobulin can be designated as a marker protein of the monocyte/macrophage differentiation. Endotoxin (Salmonella typhi) in a concentration as low as 100 ng/ml strongly represses alpha 2-macroglobulin synthesis both in monocytes and macrophages. Furthermore, endotoxin completely abolishes the induction of alpha 2-macroglobulin synthesis during the course of normal monocyte in vitro cultivation, indicating that endotoxin is a strong inhibitor of the monocyte-macrophage maturation. In contrast to alpha 2-macroglobulin, alpha 1-proteinase inhibitor synthesis is strongly stimulated by endotoxin in monocytes as well as in macrophages.

Pancreatic pseudocysts: a biochemical evaluation of proteases and protease inhibitors in plasma

A biochemical evaluation was performed on plasma from eight patients developing a pancreatic pseudocyst during acute pancreatitis attacks and from six patients with a known pseudocyst. Patients developing an acute pancreatic pseudocyst had high levels of activated trypsin in complex with alpha 1-protease inhibitor, together with a probable activation of the kinin, complement, coagulation and fibrinolytic systems. Profound changes were also seen in several protease inhibitors, indicating consumption of the inhibitors. The changes did, however, not differ from those seen in severe acute pancreatitis attacks in which no pseudocyst developed. Patients with chronic pancreatic pseudocysts had biochemical changes similar to those seen in moderate pancreatitis attacks, without any overt cascade system activation. At convalescence, however, these patients had biochemical signs of leakage from the pancreas and an ongoing proteolytic activity.

The elimination of trypsin--alpha-macroglobulin complexes from the blood circulation in pigs during acute pancreatitis and after massive intravenous trypsin infusion

The elimination from plasma of intravenously injected 125I-labelled trypsin-alpha-macroglobulin complexes was studied in both healthy and diseased, anaesthetized pigs. The t1/2 for the 125I-labelled complexes was 5-10 min in healthy pigs as well as in two groups of pancreatitis pigs. Pre-loading of the eliminating capacity by massive intravenous trypsin infusion, raised t1/2 to 80-100 min. Thus, the eliminating capacity seems to be saturable. Elimination of the complexes from the blood circulation occurred within 4-5 h. Even massive intravenous amounts of trypsin-alpha-macroglobulin complexes gave no demonstrable complement or kinin activation. Neither were other deleterious effects seen during the experiment or during 7 days of follow-up. The results indicate that treatment of acute pancreatitis in humans with alpha 2-macroglobulin might be possible, without any danger arising from the protease-alpha 2-macroglobulin complexes formed.

C1 activation and dissociation in disease

The composition of complexes containing C1 inactivator (C1 IA), C1r and C1s was investigated in normal serum after activation of C1 under various conditions. Analyses were performed with PAGE of eluates from Sepharose beads coated with F(ab')2 fragments of anti C1s followed by immunoblotting with anti C1 IA, anti C1s or anti C1r. Eluates obtained from serum treated with aggregated IgG (AGG) contained C1 IA in complex with C1r and C1s with both subcomponents in activated form. Eluates from serum incubated at 37 degrees C for 1, 2 or 3 days without activators showed C1 IA complexed with activated C1r and with C1s in proenzyme state associated to the complex. On analysis of serum, treated as mentioned above, by a variant of the electroimmunoassay using an intermediate gel containing anti-C1 IA and with anti-C1s in the anodal gel the two types of C1r--C1s--C1 IA complexes could be distinguished. Investigation of fresh sera and synovial fluids from patients with rheumatoid arthritis in this assay showed complexes containing C1 IA and C1r-C1s in activated form in the synovial fluids, while C1 IA-activated C1r-proenzyme C1s complexes were found in the corresponding sera.

Protective effect of glucan-enhanced macrophage function in experimental pancreatitis

In an effort to assess the impact of enhanced macrophage function in acute pancreatitis, mice were subjected to a choline-deficient diet supplemented by ethionine to induce necrotizing pancreatitis. Treatment with the macrophage stimulant glucan resulted in improved survival rates (58 percent versus 14 percent) and maintenance of pancreatic architecture. Glucan treatment also resulted in decreased plasma and peritoneal trypsin activity, as well as increased trypsin-binding activity in the blood and peritoneal cavity. Plasma interleukin-1, as well as macrophage production of interleukin-1, were increased in the glucan-treated mice, which indicated enhanced macrophage function. These composite findings suggest that by enhancing diverse aspects of reticuloendothelial function, clinical use of immunomodulators may have significant impact on the pathogenesis of acute pancreatitis.

The effect of peritoneal exudate on peritoneal morphology in experimental acute pancreatitis. A histologic and scanning electron microscopic study

Changes in peritoneal morphology were examined histologically and by scanning electron microscopy during porcine acute hemorrhagic (n = 8) and edematous (n = 9) pancreatitis and after intraperitoneal installation of hemorrhagic pancreatitis-associated peritoneal exudate in healthy piglets (n = 3). In all experimental groups peritoneal inflammatory changes with mesothelial damage were evident already 1 h after the induction of the disease, and increased with time. Hemorrhagic pancreatitis caused desquamation of mesothelial cells and denudation of the basal membrane. Intraperitoneal installation of hemorrhagic pancreatitis-associated peritoneal exudate in healthy piglets caused similar changes, whereas the changes in edematous pancreatitis were much less extensive. Peritoneal exudate accumulating in the peritoneal cavity during hemorrhagic pancreatitis caused early chemical peritonitis characterized by severe inflammation of the peritoneum with destruction of the mesothelial cell layer, leading to denudation of the underlying connective tissue. The significance of these changes in the pathophysiology of acute fulminant pancreatitis remains to be further studied.

The composition of diet in conjunction with chronic ethanol consumption alters plasma proteinase inhibitor levels in rats

To study the effects of dietary composition and chronic ethanol ingestion on plasma proteinase inhibitor (PI) levels in intact animals, 192 male Wistar rats were divided into 4 groups, which received a standard diet (S), a fat-rich diet (F), a protein-rich diet (P), and a carbohydrate-rich diet (C), respectively, for 12 weeks. Half of the animals in each diet group had 15% ethanol as their drinking solution (A) during this diet period, and the rest drank tap water (W). FW and CW diets caused a significant decrease in the trypsin-inhibiting capacity (TIC) of plasma in comparison with the SW group (p less than 0.05 and p less than 0.001, respectively), and chronic ethanol ingestion in combination with P and C diets decreased plasma TIC levels significantly (p less than 0.01 and p less than 0.001) when compared with the corresponding water-drinking groups. The chymotrypsin-inhibiting capacity (CIC) of plasma behaved differently: in the FW, PW, and CW groups it was significantly higher than in the SW group (p less than 0.001). Chronic ethanol ingestion did not change plasma CIC levels significantly when compared with the corresponding water-receiving groups. In conclusion, dietary intake was found to alter plasma PI levels. Changes in the protein synthesis of the liver might be responsible for these alterations.

Consumptive coagulopathy, fibrinolysis and protease-antiprotease interactions during acute human pancreatitis

Twenty-seven attacks of acute human pancreatitis of different severity were analysed concerning clinical outcome and activation of the coagulation and fibrinolytic systems. Consumptive coagulopathy was suggested by decreased platelet counts, decreased prothrombin values and consumption of fibrinogen during the first days in severe attacks. Factor X was slightly decreased the first 5 days in all attacks. Increased fibrinolysis was suggested by decreased plasminogen values in severe attacks. Fibrinogen degradation products were seen in 40% of the patients in blood and in 100% of the patients in the peritoneal fluid. The four main protease inhibitors of the two systems all showed protease-antiprotease complexation and lower functional than quantitative values. Plasma levels of antithrombin III and alpha 2-macroglobulin were low, while the levels of C1-inhibitor and alpha 2-antiplasmin were high. Functional levels of all the four protease inhibitors were almost zero in the peritoneal fluid in severe attacks. It is concluded that severe acute pancreatitis results in both consumptive coagulopathy and in increased fibrinolysis. A local antiprotease deficiency is seen in the peritoneal cavity and high levels of protease-antiprotease complexes are also seen in plasma. All these changes are closely correlated to the severity of the disease and may probably determine the clinical outcome of the acute attack.

Disseminated intravascular coagulation and antiprotease activity in acute human pancreatitis

The coagulation and fibrinolytic systems were analysed parallel to the clinical evaluation in 27 attacks of acute human pancreatitis of different severity. Consumptive coagulopathy was evident from decreased platelet counts, decreased prothrombin values and consumption of fibrinogen during the first days in severe attacks. Fibrinolysis was suggested by decreased plasminogen values and the presence of fibrinogen degradation products. All main protease inhibitors of the two systems showed protease-antiprotease complexation and lower functional than quantitative values. Functional levels of the protease inhibitors were almost zero in the peritoneal fluid in severe attacks. It is concluded that severe acute pancreatitis results in consumptive coagulopathy and fibrinolysis together with a local antiprotease deficiency. All the changes are closely correlated to the severity of the disease.