J. O. Stadaas

Studies on the Plasma Kallikrein-Kinin System in Peritoneal Exudate and Plasma during Experimental Acute Pancreatitis in Pigs

Acute pancreatitis was induced in pigs by retrograde injection of Na-taurocholate into the pancreatic duct. By means of chromogenic peptide substrate assays, increased plasma kallikrein activity, parallel with a reduction of plasma prekallikrein and functional kallikrein inhibition values, was found in peritoneal exudate. In plasma, however, no changes in the kallikrein-kinin system were found during the 6-h observation time. The study demonstrates the presence of components of the plasma kallikrein-kinin system in peritoneal fluid and suggests that the peritoneal cavity to a great extent is a functionally separate compartment from plasma. Activation of the plasma kallikrein-kinin system in peritoneal exudate during acute experimental pancreatitis appears to be of importance for the initial symptoms and the development of shock seen during this condition.

Studies on components of the contact phase system in patients with advanced gastrointestinal cancer

The authors have studied components of the contact system in plasma obtained from patients with advanced gastrointestinal cancer. Plasma samples from 118 healthy blood donors served as controls. Plasma prekallikrein (PKK) values, evaluated by chromogenic peptide substrate technique, were significantly decreased in patients with cancer compared with healthy blood donors. High molecular weight kininogen (HMwK) and Hageman factor (FXII) values, assayed by immunochemical techniques, were also decreased in the patients with cancer. The changes of contact factors were most pronounced in patients with liver metastasis. The most striking observation in our study, however, was the elevated inhibitor values in patients with cancer. Alpha‐2‐macroglobulin (α2M) and C1 inhibitor (C1INH) values, determined both by functional and immunochemical techniques, were markedly increased in patients with cancer. In conclusion, this study shows that patients with intestinal cancer have reduced values of contact factors and markedly elevated inhibitor values which indicate that development of malignant tumors in the gastrointestinal tract is associated with changes in the contact system of plasma.

Effects on peritoneal proteolysis and hemodynamics of prophylactic infusion with C1 inhibitor in experimental acute pancreatitis.

Acute pancreatitis was induced in pigs by manual retrograde injection of Na-taurocholate into the pancreatic duct. Chromogenic peptide substrate assays showed increased trypsin (TRY) and plasma kallikrein activities (KK), parallel with a reduction of prekallikrein (PKK) levels and functional plasma kallikrein inhibition (KKI), in the peritoneal exudate in untreated animals. Pretreatment with C1 inhibitor (C1 INH) concentrate significantly increased the KKI capacity, parallel with unchanged KK and TRY activities in the peritoneal exudate. Furthermore, C1 INH pretreatment significantly improved the hemodynamic performance and the survival rate during a 6-h observation period. The study underlines the pathophysiological importance of trypsin and the plasma kallikrein-kinin system during acute pancreatitis. C1 INH concentrates given intravenously prevent activation of this system locally in the peritoneal exudate during experimental acute pancreatitis.

Effects on peritoneal proteolysis and hemodynamics of prophylactic and therapeutic infusions of high doses of aprotinin in experimental acute pancreatitis.

Acute pancreatitis was induced in pigs by retrograde injection of Na-taurocholate into the pancreatic duct. Chromogenic peptide substrate assays showed increased trypsin (TRY) and plasma kallikrein activity (KK), parallel with a reduction of plasma prekallikrein (PKK) and functional kallikrein inhibition (KKI) values, in the peritoneal exudate in untreated animals. Intravenous high-dose pretreatment or therapy with aprotinin starting 3 h after the induction of acute pancreatitis resulted in significantly increased KKI capacity and unchanged KK and TRY activities in the peritoneal exudate. In test animals receiving aprotinin intravenously a significantly increased survival rate and improved cardiac output and arterial blood pressure were found during the 6-h observation period. All animals treated with aprotinin survived the observation period, whereas 63% of the untreated animals died. The study emphasizes the pathophysiological importance of the plasma kallikrein-kinin system in acute pancreatitis.

Methylprednisolone in High Doses Gives Different Effects on the Early and the Late Part of Complement

The effects of methylprednisolone (MP) on endotoxin-induced activation of complement were studied in citrated pool plasma. Complement activation was tested in two immunoassays: one evaluating C3 activation fragments (C3act) and the other the terminal complement complex (TCC). These components are indicators of initial and terminal complement activation, respectively. Plasma samples were obtained at 1, 2, 4 and 6 h of incubation. Plasma containing endotoxin (2.10(9) ng/l) without MP revealed a marked increase of both C3act and TCC after 1 h. MP in high doses (10 mg/ml) gave an additive effect on activation of the initial part of the complement cascade compared to test plasma containing only endotoxin. In contrast, endotoxin-induced activation of the terminal part of the complement cascade was inhibited by the same dose of MP. The influence of lower doses of MP (0.1 and 1 mg/ml) on endotoxin-induced activation of complement was insignificant. Interestingly, MP without endotoxin induced activation of the initial part of complement. In test plasmas containing 5 and 10 mg/ml of MP (without endotoxin) marked increases of C3act values were seen. Despite this obvious activation of the early part of complement, only insignificant changes were found in TCC values. Test plasmas containing 0.1 and 1 mg/ml of MP revealed only minor changes in both C3act and TCC. In conclusion, the present study shows that high doses of MP activate the initial part of complement and that the endotoxin-induced activation of this cascade system was facilitated by MP. The terminal part of complement was, on the other hand, inhibited by high doses of MP.

Peritoneal lavage efficiently eliminates protease-alpha-2-macroglobulin complexes and components of the contact system from the peritoneal cavity in patients with severe acute pancreatitis.

Trypsin (Try), plasma kallikrein (KK) and plasmin activities together with coagulation factor XII (F XII, Hageman factor), high-molecular-weight kininogen (HMWK), plasma prekallikrein (PKK), alpha 2-macroglobulin (alpha 2-M), C1 inhibitor (C1Inh), and functional plasma kallikrein inhibition (KKI) values were studied in peritoneal fluid and lavage taps of 9 patients with severe acute pancreatitis treated with peritoneal lavage. Both immunochemical methods and functional techniques based on chromogenic peptide substrate assays were used. In the exudate obtained before peritoneal lavage was performed, F XII was 52%, HMWK was 30%, PKK was 40%, alpha 2-M was 29% and C1Inh was 57% of standard plasma pool values, determined by immunochemical technique. Functional plasma KKI values were zero, whereas Try activities determined by chromogenic peptide substrate technique were markedly elevated in the exudate. Using a prepacked HR 10/30 Superose Tm 12 column (Pharmacia, Uppsala, Sweden) and chromogenic peptide substrate assays, Try and KK activities were detected in the alpha 2-M containing fractions of the peritoneal exudate demonstrating KK-alpha 2-M and Try-alpha 2-M complex formation. The peritoneal lavage procedure efficiently eliminated components of the contact system and protease activities. In the first lavage tap, Try activities were markedly reduced compared to values found in the exudate and concentrations of F XII, HMWK, PKK, alpha 2-M and C1Inh were all zero. In consecutive lavage taps Try values were also zero. The study shows that the lavage procedures efficiently clears the peritoneal cavity for protease-alpha 2-M complexes generated during acute pancreatitis. Also, components of the contact system found in peritoneal exudate, and which might serve as substrates for the protease-alpha 2-M complexes, are rapidly eliminated by the procedure.

Evaluation of patients with acute pancreatitis by means of chromogenic peptide substrate assays and the proenzyme functional inhibition index

Using chromogenic peptide substrate assays the severity and clinical course were evaluated in 37 patients with acute pancreatitis. Retrospective clinical evaluation revealed that 20 patients had a severe disease, whereas 17 patients had mild acute pancreatitis. Seven of the patients with severe acute pancreatitis died. The proenzyme functional inhibition index (PFI index) is defined as the sum of deviations from the normal plasma pool values of plasma prekallikrein, functional kallikrein inhibition, plasminogen, antiplasmin, prothrombin and antithrombin III. Increased values are counted as positive, whereas reductions compared with the normal plasma pool values are recognized as negative. During the second day after admission the PFI index revealed significantly more negative values in severe cases than in patients with mild acute pancreatitis, -159 in severe case, -74 in mild cases (median values, P less than 0.05). The PFI index values were maintained strongly negative for the following 3 days in severe cases whereas the index was brought to positive values during the same period in patients with mild acute pancreatitis. The fatal cases revealed strongly negative PFI index values for the whole observation period. The patients with severe acute pancreatitis were earlier identified by means of the PFI index than by individual parameters also used for calculating the index. The results show that by means of the PFI index severity of acute pancreatitis can be recognized during early stages of the disease.

Effects on Peritoneal Proteolysis and Hemodynamics by High Doses of Methyl-Prednisolone in Experimental Acute Pancreatitis

Acute pancreatitis was induced in 15 anesthetized pigs by injection of Na-taurocholate into the pancreatic duct. Seven animals were pretreated with methyl-prednisolone sodium succinate 30 mg/kg intravenously. Using chromogenic peptide substrate assays, values of trypsin (TRY), plasma prekallikrein (PKK), plasma kallikrein (KK) and functional plasma kallikrein inhibition capacity (KKI) were studied in the peritoneal exudate. Cardiac output (CO) and arterial pressure (AP) were regularly monitored before and during a six hour observation period. In acute untreated pancreatitis a 40% reduction of PKK levels was found paralleled by an increased KK activity and a reduction of KKI capacity. High TRY levels were found in several animals. The mortality rate was 63%. The pretreated animals all survived. CO and AP were significantly less reduced than in the untreated animals. Components of the plasma kallikrein-kinin system and TRY in the exudate remained mainly unchanged. Methyl-prednisolone given as pretreatment significantly improves hemodynamic parameters and increases the survival rate. Methyl-prednisolone suppresses generation of trypsin activity and activation of the plasma kallikrein-kinin system in the peritoneal exudate which may be of significant importance to the outcome.

Combined Drug Therapy in Porcine Endotoxemia

In order to investigate the importance of potential mediators of pathophysiologic derangements in endotoxemia, we have examined the effects of the combined administration of antagonists against histam

Methylprednisolone induces activation of the contact system in a dose-dependent manner. An in vitro study.

The effect of methylprednisolone sodium succinate (MP) on the contact system of plasma was studied in human citrated pool plasma. Contact activation was demonstrated by the presence of plasma kallikrein (KK) activity and activated Hageman factor (FXIIa) and/or KK in complex with C1 inhibitor (C1inh), detected by chromogenic peptide substrates or radioimmunoassays, using monoclonal antibodies directed to neodeterminants exposed on complexed C1inh, respectively. When plasma and different doses of MP were incubated for a period of 24 hours, the highest dose of MP (10 mg/ml) gave rapid and marked increases in KK activities and concentrations of C1inh complexes. MP at 5 mg/ml plasma also induced activation of the contact system, although this activation was less pronounced. Even the lower dose of MP (1 mg/ml), which is equivalent to doses used in humans, increased plasma concentrations of KK-C1inh complexes. In conclusion, this in vitro study shows that MP in a dose-dependent way activates the contact system of plasma.