Elastase-alpha 1-proteinase inhibitor: an early indicator of septicemia and bacterial meningitis in children

In 26 infants and children with septicemia or bacterial meningitis, significantly elevated plasma levels of elastase-alpha 1-proteinase inhibitor (E-alpha 1-PI) were present at time of recognition of infection, even in those patients with neutropenia (range of reference values: 25 to 190 micrograms/L, n = 142; patients: 444 to 2049 micrograms/L, n = 26). After initiation of therapy, normalization of E-alpha 1-PI levels was observed in all patients who recovered from infection. In addition, 18 of 19 children with bacterial meningitis had increased cerebrospinal fluid concentrations of E-alpha 1-PI above the range of normal (range of reference values: 0 to 39 micrograms/L, n = 62; patients: 30 to 3490 micrograms/L, n = 19); concentrations of E-alpha 1-PI in bacterial meningitis were significantly increased when compared with those in aseptic meningitis (range 25 to 194 micrograms/L; n = 15). In 30 patients with local bacterial infections (pneumonia, urinary tract infections, etc.), E-alpha 1-PI was also elevated. These data suggest that E-alpha 1-PI is a sensitive indicator of systemic and local bacterial infection in childhood.

The role of inter-alpha-trypsin inhibitor and other proteinase inhibitors in the plasma clearance of neutrophil elastase and plasmin

The plasma clearance of neutrophil elastase, plasmin, and their complexes with human inter-alpha-trypsin inhibitor (I alpha I) was examined in mice, and the distribution of the proteinases among the plasma proteinase inhibitors was quantified in mixtures of purified inhibitors, in human or murine plasma, and in murine plasma following injection of purified proteins. The results demonstrate that I alpha I acts as a shuttle by transferring proteinases to other plasma proteinase inhibitors for clearance, and that I alpha I modulates the distribution of proteinase among inhibitors. The clearance of I alpha I-elastase involved transfer of proteinase to alpha 2-macroglobulin and alpha 1-proteinase inhibitor. The partition of elastase between these inhibitors was altered by I alpha I to favor formation of alpha 2-macroglobulin-elastase complexes. The clearance of I alpha I-plasmin involved transfer of plasmin to alpha 2-macroglobulin and alpha 2-plasmin inhibitor. Results of distribution studies suggest that plasmin binds to endothelium in vivo and reacts with I alpha I before transfer to alpha 2-macroglobulin and alpha 2-plasmin inhibitor. Evidence for this sequence of events includes observations that plasmin in complex with I alpha I cleared faster than free plasmin, that plasma obtained after injection of plasmin contained a complex identified as I alpha I-plasmin, and that a murine I alpha I-plasmin complex remained intact following injection into mice. Plasmin initially in complex with I alpha I more readily associated with alpha 2-plasmin inhibitor than did free plasmin.

Studies of protease and protease inhibitors in familial amyloidotic polyneuropathy

Serum levels of 6 protease inhibitors, alpha 1-antitrypsin, Cl inactivator, alpha 2-macroglobulin, antithrombin-3, alpha 1-antichymotrypsin and inter-alpha-trypsin inhibitor were measured in patients with familial amyloidotic polyneuropathy (FAP) and a control group without neurologic disease. No significant differences were observed between the 2 groups. The proteolytic effect of brinase, an enzyme from Aspergillus oryzae, on amyloid tissue sections from patients with FAP was also evaluated. Amyloid fibrils were degraded by brinase, while the tissue structure remained fairly intact.

Studies on the turnover of methionine oxidized alpha-1-protease inhibitor in rats

Alpha-1-protease inhibitor (alpha-1-PI) is the major regulator of extracellular leukocyte elastase activity and can be rendered impotent against elastase by oxidation of a critical methionine, residue 358. Alpha-1-PI was isolated from rat plasma by affinity chromatography on Sepharose-bound anhydrochymotrypsin, DEAE-cellulose anion-exchange, and Sephadex G-150 gel filtration. The product was radiolabeled using non-oxidative conditions with Bolton-Hunter reagent, and an aliquot subsequently oxidized with N-chlorosuccinimide. Turnover studies in rats indicated that both native and oxidized alpha-1-PI had half-lives of 170 min. Using partially purified human neutrophil methionine sulfoxide-peptide reductase (Met(O)PR), it was demonstrated that oxidized product could be converted back "in vitro" to an active inhibitor of elastase. To assess whether oxidized alpha-1-PI underwent reduction "in vivo," methionine-oxidized rat inhibitor was injected into the rats, aliquots of plasma samples were withdrawan and passed through a Sepharose-bound anhydrochymotrypsin affinity resin, and bound functional alpha-1-PI was eluted with 0.1 M chymostatin. Radioactive counting of bound and unbound fractions indicated that reduction does not occur in vivo and suggested that, at least under homeostatic conditions, the Met(O)PR is confined to intracellular sites where it does not have access to the circulating protein.

[Effect of trypsin and kallikrein (andecalin) on the activity of proteolytic enzymes and their inhibitors in acute experimental pancreatitis]

Intramuscular administration of trypsin and kallikrein (andecaline) into rats contributed to more favourable development of acute traumatic pancreatitis. Trypsin and andecaline prevented the activation of proteinases in blood serum and pancreas and promoted an increase in content of trypsin inhibitor in blood serum. The proteinases efficiency appears to depend on elevation of general resistance of the organism to the trauma.

Rat plasma alpha 1-inhibitor3 binds to receptors for alpha 2-macroglobulin

The cellular binding and uptake was studied for alpha 1-inhibitor3, a monomeric 200 kDa proteinase inhibitor present in rat plasma. After intravenous injection in the rat the inhibitor disappeared from the circulation with a half-time of 2.5 min when complexed with chymotrypsin, whereas the half-time for uncomplexed inhibitor was more than 60 min. 6 min after the injection of labelled complex, 83% was in the liver and 2.5% in the spleen. In vitro experiments at 4 degrees C with isolated hepatocytes and peritoneal macrophages showed binding to the previously described receptors which bind and internalize the tetrameric rat and human alpha 2-macroglobulin-proteinase complexes. The binding affinities were similar for the two types of complexes and binding was followed by uptake and degradation of the labelled complex when the cells were warmed to 37 degrees C. The binding of uncomplexed alpha 1-inhibitor3 was low and did not increase following treatment with methylamine in spite of cleavage of the internal thiol ester. alpha 1-Inhibitor3-methylamine was changed to the receptor binding form when treated with chymotrypsin which caused the cleavage of at least one peptide bond in the bait region.

Granulocyte elastase-alpha 1-antiproteinase complex in cystic fibrosis: sensitive plasma assay for monitoring pulmonary infections

Elastase in plasma was determined as a complex of granulocyte elastase and alpha 1-antiproteinase (GEC) by an enzyme-linked immunosorbent assay in 67 patients with cystic fibrosis. The patients were observed for 1 years, when clinically infected and noninfected. Although noninfected patients had GEC levels within the normal range, the mean value was significantly higher than the mean values in patients in an optimal noninfectious state (P less than 0.01) and in healthy controls (P less than 0.001). Clinical signs of (in most cases) low-grade infection were paralleled by significant increases in GEC levels (P less than 0.001). There was no correlation with different types of bacteria or age of patients. No cross reaction to Pseudomonas elastase could be found in vitro or in vivo. Significant decreases of GEC values were seen after intravenously administered antimicrobial therapy (P less than 0.001), and although the white blood cell count and erythrocyte sedimentation rate were rarely increased above the normal range, they decreased congruently (P less than 0.001), and lung function improved (P less than 0.001). The sensitivity of GEC was significantly higher than that for erythrocyte sedimentation rate (P less than 0.01) and white blood cell count (P less than 0.05). Determination of GEC values seems to be a simple and sensitive measurement for monitoring treatment in cystic fibrosis, especially of low-grade infections in patients with normal standard blood tests.

Proteases and antiproteases related to the coagulation system in plasma and ascites--an approach to differentiate between malignant and cirrhotic ascites

The concentrations of several proteases and antiproteases known to be present in ascites were tested in plasma and ascitic fluid with regard to their ability to separate ascites according to malignant or nonmalignant disease. Seventeen patients with proven malignant ascites and 37 with ascites due to liver cirrhosis were included. Activities of plasminogen, alpha 2-antiplasmin, antithrombin-III, and factor V, and the concentration of alpha 1-protease inhibitor were significantly higher in the plasma of patients with malignant ascites than in cirrhotic patients. Fibronectin, plasminogen, alpha 2-macroglobulin, alpha 1-protease inhibitor, antithrombin-III, and albumin revealed higher concentrations or activities in malignant ascites than in cirrhotic ascites. Due to a wide variation of most parameters, only fibronectin, antithrombin III, and alpha 1-protease inhibitor in ascites had a sensitivity and specificity higher than 90% for malignant ascites. When the specific protein/albumin ratio was used, only the accuracy of fibronectin was increased reaching a sensitivity and specificity of 100%. The plasma/ascites gradients of the proteins assessed differed significantly, that of fibronectin being much higher (22 +/- 7) than that of all other proteins. In malignant ascites fibronectin concentration was only correlated with alpha 1-protease inhibitor concentration but not with the concentration or activity of all other proteins, while in cirrhotic ascites most proteins revealed a positive correlation. The determination of the fibronectin concentration or the fibronectin/albumin ratio in ascites can differentiate malignant and nonmalignant ascites. All other proteases and antiproteases assessed are of lesser value for this purpose, although most are significantly increased in ascites and plasma of patients with malignant disorders.

Proteases and antiproteases related to the coagulation system in plasma and ascites--influence of dexamethasone

Fibrinolysis induced by the infusion of plasminogen activators into the circulation has been shown to cause coagulation disorders in ascites retransfusion. Dexamethasone is known to inhibit the synthesis of plasminogen activators by peritoneal macrophages. We therefore assessed its potential in preventing the occurrence of fibrinolysis by injecting 16 mg dexamethasone intraperitoneally in 10 patients 24 h before ascites retransfusion was performed. In addition, the effect of dexamethasone upon the activity or concentration of several proteases and antiproteases related to coagulation in plasma and ascites was analyzed on 15 occasions. An increase of the activity of plasminogen, alpha 2-antiplasmin, and antithrombin III, and in the concentration of alpha 1-protease inhibitor in ascites was induced by the dexamethasone injection. However, the reaction was not identical in all patients. Those patients having an increase of plasminogen activities of 0.6 CTA U/ml or more did not show signs of fibrinolysis during retransfusion. The results obtained indicate that intraperitoneal injection of dexamethasone decreases the concentration of plasminogen activators in ascites and thereby reduces the risk of coagulation disorders during retransfusion procedures. Since the effect is variable and not sustained, assessment of preoperative plasminogen concentrations is mandatory in order to prevent complications.

Purification of C1 inhibitor. A new approach for the isolation of this biologically important plasma protease inhibitor

C1 inhibitor (C1-INH) acts to inhibit active enzymes of both the classical complement and Hageman factor-dependent pathways. Previously reported C1-INH purification procedures were multistep and most have been associated with significant loss in specific functional activity. We have developed a simple chromatographic procedure which yields a pure C1-INH protein from normal human plasma with a specific activity equal to or greater than the starting sample. Briefly, protease inhibitor-treated, pooled human citrated plasma was fractionated with polyethylene glycol (PEG 4000); the supernatant fraction that remained soluble at 16% was obtained. The inhibitor was precipitated with 45% PEG. The resulting precipitate was solubilized and chromatographed on DEAE Sephacel using a linear salt gradient. The eluted fractions containing the C1-INH and other contaminants were pooled and dialyzed against the starting buffer of the next chromatographic step. A unique separation procedure using zinc ion chelate-coupled agarose was employed as the second chromatographic step. The eluted C1-INH, after zinc ion chromatography, displayed a significant enhancement in purity and maintained a specific functional activity twice that of plasma. The final procedure utilized immunoadsorption chromatography using an anti-contaminant column. Under reducing conditions on sodium dodecyl sulfate polyacrylamide gel electrophoresis, the purified C1-INH migrated as a single band with an apparent molecular weight of 90,000-105,000, but under non-reducing conditions, a doublet with apparent molecular weights of 94,000-100,000 and 85,000-93,000 was seen. C1-INH antigenic concentrations were measured and shown to be correlated in serum, citrate plasma, and EDTA plasma from 16 normal subjects.

[A case report of hereditary angioedema and studies on the serum components of complement, C1-inactivator and proteinase inhibitors during edema attack]

Sixteen years old girl was admitted because of for the past ten years' frequent edema attack and abdominal pain. Laboratory examination revealed hypocomplementemia, marked depletion of the fourth component of complement and low level of C1-inactivator. Familial studies revealed that her mother was also hypocomplementemic and in low level of C1-inactivator. Serial studies performed on the alterlation of components of complement, C1-inactivator, alpha 1-antitrypsin, antithrombin III, and alpha 2-macroglobulin during edema attack. The fourth component of complement and C1-inactivator were markedly depleted in remission and attack. Remarkable depletion was found in antithrombin III and esterase inhibition activity of C1-inactivator during attack. In contrast, alpha 1-antitrypsin and alpha 2-macroglobulin did not change. The present study may explain that Hageman factor fragments, activated by C1s, promotes kinin generation via kalikrein activation. And the condition that complete functional deficiency of C1-inactivator was main role in this circuit. Fibrynolysis and late components of complement was less influence on edema attack.

Regulation of factor VIIa activity in plasma: evidence that antithrombin III is the sole plasma protease inhibitor of human factor VIIa

The inhibition of human factor VIIa by antithrombin III and normal human plasma was studied in the presence and absence of heparin. In the absence of heparin, no apparent inhibition of factor VIIa was observed in either system. In the presence of heparin, factor VIIa activity was inhibited 50% by purified antithrombin III and plasma in 90 min and 75 min, respectively. No inhibition of factor VIIa was observed in heparinized plasma previously depleted of antithrombin III by immunoaffinity adsorption. Incubation of factor VIIa with antithrombin III-heparin or heparinized plasma resulted in the formation of a covalent complex with an apparent molecular weight of 100 kilodaltons. These data indicate that antithrombin III appears to be the sole plasma protease inhibitor of human factor VIIa, and the expression of its inhibitory activity against factor VIIa is absolutely dependent upon the presence of exogenous heparin.

Three high molecular weight protease inhibitors of rat plasma. Reactions with trypsin

We have compared the reactions of trypsin with human alpha 2-macroglobulin (alpha 2M), and three rat plasma protease inhibitors, alpha 1-macroglobulin (alpha 1M), alpha 1-inhibitor III (alpha 1I3), and alpha 2M. All four of these proteins appear to contain reactive thiol esters. The electrophoretic mobility in agarose gels of human and rat alpha 2M is increased by 1 mol of trypsin, while the mobility of alpha 1M and alpha 1I3 is decreased. Treatment with methylamine causes similar mobility changes, except in the case of rat alpha 2M. Titration of human and rat macroglobulins by repeated small additions of trypsin and by assay of liberated SH groups or enhanced ligand fluorescence revealed a stoichiometry of about 1 mol of trypsin/mol of inhibitor. In contrast, addition of macroglobulin to a fixed amount of trypsin and detection of residual amidase or protease activity revealed a stoichiometry of about 2 mol of trypsin for 1 mol of human alpha 2M, about 1.4 mol for rat alpha 1M, and about 1 mol for rat alpha 2M. One mol of trypsin reacted with 2 or more mol of alpha 1I3 by the criteria of SH groups liberated or protease inhibition. Methylamine-treated rat alpha 2M binds a significant amount of trypsin releasing about 2 mol of SH. Radioactive beta-trypsin was covalently bound to subunits of the purified plasma inhibitors. The Mr of the labeled products with rat and human alpha 2M had molecular weights which suggested trypsin was bound to intact as well as cleaved subunit chains and also to multiple chains via cross-linking. Rat alpha 1M also produced a product which may be an intact subunit alpha chain plus trypsin. Greater than 80% of the trypsin was bound covalently to these inhibitors at low molar ratios.

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.

Beneficial effects of danazol on symptoms and laboratory changes in cholinergic urticaria

In a double-blind placebo-controlled study, danazol, an attenuated androgen, was effective in reducing exercise-induced weals in cholinergic urticaria. Danazol treatment also caused significant elevations of several protease inhibitors, particularly antichymotrypsin which has been reported previously to be low in cholinergic urticaria.

Raised serum concentrations of pancreatic enzymes in cigarette smokers

Circulating concentrations of digestive enzymes, certain lysosomal hydrolases and protease inhibitors were measured in 19 heavy smokers and 13 non-smokers before (basal) and at 15, 30, and 60 minutes after a single intravenous injection of secretin (75 CU). In smokers, basal serum amylase and immunoreactive pancreatic elastase 2 (IRE2) concentrations were about 100% and 25% higher respectively, than in the non-smokers, whereas, no differences were observed in basal immunoreactive cationic trypsinogen (IRCT) concentrations and in acid phosphatase and beta-glucuronidase activities between the two groups. Furthermore, a single injection of secretin to cigarette smokers significantly increased serum amylase, IRCT and IRE2 by 155%, 200%, and 100%, respectively when compared with their corresponding basal levels. No such increment was observed in the non-smokers. In addition, there were no significant differences in serum trypsin or elastase inhibitory capacity or immunoreactive alpha 1-protease inhibitor and alpha 2-macroglobulin levels between smokers and non-smokers. The levels and inhibitory capacity of these protease inhibitors was also not affected by secretin injection. These data suggest that cigarette smoking enhances the responsiveness of the exocrine pancreas to a physiological stimulus such as secretin, with resultant substantial increase in the concentrations of pancreatic hydrolases in blood.

Effect of smoking on functional activity of plasma alpha 1-protease inhibitor

We determined the levels of alpha 1-protease inhibitor, the plasma trypsin-inhibiting capacity (TIC), and elastase-inhibiting capacity (EIC) in 29 nonsmokers and 30 smokers, who were healthy volunteers matched for age (mean age, 39 +/- 12 years [+/- SD]). The functional activity of plasma alpha 1-protease inhibitor (in micrograms of enzyme inhibited per microgram of alpha 1-protease inhibitor) was slightly but significantly lower in smokers, compared with nonsmokers, both for TIC and EIC (smokers' TIC and EIC were 88.0 +/- 16.2 percent (+/- SD) and 90.4 +/- 17.9 percent of the respective mean values in nonsmokers; p less than 0.05). Among smokers, there was a significant negative correlation (r = -0.37; p less than 0.05) between the average number of cigarettes smoked per day and the functional activity of plasma alpha 1-protease inhibitor; the seven subjects who smoked 40 or more cigarettes per day had significantly lower EIC and TIC than the remaining smokers. In 12 smokers tested before and after a two-hour period of intense smoking of eight cigarettes, there was a statistically significant decrease (p less than 0.05) in EIC one hour after smoking to 93.9 +/- 2.5 percent (+/- SE) of the initial value prior to smoking. It is concluded that there is a slight but significant decrease in the functional activity of plasma alpha 1-protease inhibitor in smokers, both for TIC and EIC.

Digestive enzymes and protease inhibitors in plasma from patients with acute pancreatitis

The plasma levels of certain digestive enzymes and protease inhibitors were determined in 40 patients with severe acute pancreatitis diagnosed as gallstone-induced (GP), alcoholic (AP), or idiopathic (IP). On admission, plasma levels of amylase and immunoreactive cationic trypsin(ogen) (IRCT) and elastase 2 (IRE 2) were found to be 50 +/- 10 ng/ml, 340 +/- 64 ng/ml, and 190 +/- 15 ng/ml, respectively, in all groups of patients. These enzymes levels remained high for the first 2 days following hospitalization and then decreased, although amylase and IRCT levels remained elevated above normal values throughout the study period (2 weeks). In general amylase and IRCT were lower in patients with concomitant ascites, pancreatic pseudocysts, or abscesses, and higher in patients who died, as compared to the pancreatitis group as a whole. In these patients, levels of immunoreactive alpha 1-protease inhibitor (alpha 1-PI) and alpha 2-macroglobulin (alpha 2-M) remained relatively constant at the lower end of the normal range throughout the study period. Inhibitor levels in plasma were unaffected by the etiology of pancreatitis or the occurrence of complications. A similar trend was seen with plasma levels of lysosomal hydrolases. The results indicate that in this group of patients, plasma levels of pancreatic digestive enzymes were reflective of the clinical features and severity of the disease, as well as the time following the acute attack that brought the patient to the hospital.

[Proteinase inhibitors of the blood plasma in the early period of the development of acute radiation sickness in monkeys]

A study was made of the postirradiation kinetics of blood antiproteinase activity in monkeys (Macaca nemestrina). Whole-body uniform gamma-irradiation (LD100/45) was shown to induce a significant decrease in the activity of alpha 2-macroglobulin during the first 24 h following irradiation: the decreased activity level was retained throughout the entire latent period of radiation sickness. At the height of radiation sickness (the 7th-10th day) up to the animals' death, a sharp increase was registered in the activity of alpha 1-inhibitor of blood plasma proteinases. The authors discuss a pathogenetic role of the diminution of the inhibitory potential of blood in the course of radiation sickness.