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[Kinin system components, free kinins and proteinase inhibitors in the edematous fluids of nephrotic syndrome patients].

Main components of the kinin system, free kinins, total arginine esterase activity content of alpha 1-antitrypsin and alpha 2-macroglobulin fractions were estimated in various edematous fluids (transduates of different localization, pleural exudates of the inflammatory type) of patients with nephrotic syndrome of various etiology. Noninflammatory edematous fluids (interstitial, abdominal and pleural transudates) were found to contain activated kallikrein and prekallikrein from blood plasma; 3-10 ng/ml of free kinins were present in interstitial edematous fluids and 30-60 ng/ml - in abdominal transudate. Kinins of abdominal transudate were identified with bradikinin by chromatographic properties; a single low-molecular form of kininogene was found, its content did not exceed 10% of the substance occurring in blood plasma of the patients. These edematous fluids practically did not exhibit the kininase activity and contained unsignificant amounts of proteinase inhibitors. Pleural exdates of the inflammatory type were distinctly different from transudates in content of the kinin system components. Depending on the higher content of protein (2.5% as compared with 0.3-0.7% in transudates) the exudates contained high-molecular kininogene and kininase I. Relative content of kallikrein in pleural exudates was lower and that of prekallikrein - higher as compared with transudates; acid kininogenases were not observed. Free kinins (30 ng/ml) were found in three samples of pleural exudates out of five samples studied. The inflammatory type of pleural exudates correlated with the high level of alpha 1-antitrypsin. As shown by comparative analysis of protein fractions from edematous fluids and corresponding samples of blood plasma of patients with nephrotic syndrome, diffusion is the main reason, which determines the course of protein transition from inter-into exovasal space, under conditions of increased vascular permeability. Kallikrein activation and extravasal formation of bradikinin were apparently the long-term affecting factors, supporting the state of increased vascular permeability in nephrotic syndrome; they had an aggravating role in pathogenesis of refractory nephrotic edema, nephrotic crises and cutaneous erythema.

Adolescent↗
PubMed1977

Fungal proteases and the mammalian kinin system: I. Brinolase-catalyzed kinin formation and S2160 hydrolysis.

Brinolase, a fungal protease advocated for thrombolytic therapy, released kinin peptides from semi-purified kininogens of the human, rabbit, guinea pig, and mouse, and moreover cleaved an arginyl bond of the chromogenic peptide S2160. Its kinetics demonstrated marked differences from the mammalian protease trypsin. Whereas trypsin liberated 100% of the available kinin in 30 min at pH 8, brinolase generated a maximum of only 22% under optimal conditions, viz. incubation of 5 microgram/ml enzyme at pH 4.7 for 5 min. Longer incubations yielded less detectable kinin. This maximal release at acidic pH was not due to increased kininogen consumption, nor was it inhibited by the acid protease inhibitor pepstatin. Evidence is presented that brinolase, unlike trypsin, might both release and destroy kinins.

Anilides↗
PubMed1978

Plasma-kinin-forming enzyme in human skin: extraction and column chromatographic separation of plasma-kinin-forming enzyme and its inhibitor.

The optimal salt concentration for extraction of plasma-kinin-forming enzyme from the human skin was investigated. It was confirmed that a salt concentration higher than 1.5 M in the extraction buffer was required for optimal extraction of this enzyme. An inhibitor of this enzyme was detected in the extract with buffer alone, and the coexistence of this enzyme with the inhibitor in buffer extract was also confirmed by using G-200 gel chromatography.

Bradykinin↗
PubMed1976

The influence of kinins on the action of circulatory drugs. I. The influence of kinins on hypertensive and hypotensive effects of selected drugs.

The influence of bradykinin and kallikrein on the action of norepinephrine, epinephrine, isoprenaline, phentolamine, propranolol, aminophylline and theophylline on blood pressure was studied. The kinins potentiated the hypertensive action of norepinephrine and epinephrine, weakened the hypotensive action of isoprenaline, potentiated the hypotensive action of propranolol, and had no effect on the action of phentolamine, aminophylline and theophylline.

Aminophylline↗
PubMed1979

Kinin-forming enzyme in human skin: the purification and characterization of a kinin-forming enzyme.

A kinin-forming-enzyme in human skin extract was further purified by successive column chromatography on DEAE-cellulose, Hydroxylapatite-cellulose and Sepharose-4B. By these procedures, 2.7 mg of purified enzyme was obtained from 10 gm of original skin. The purified material was homogeneous as ascertained by cellulose acetate membrane electrophoresis, sodium dodecyl sulfate polyacrylamide gel disc electrophoresis and ultracentrifugation. It had an S20,w value of 4.3 and an apparent molecular weight of 104,000 as measured by gel filtration on Sephadex G-200. The purified enzyme was comparatively heat-stable, but was unstable below pH values of 5 and above pH 9. It possessed arginine or lysine esterolytic activity, but not tyrosine or tryptophane esterolytic activity and denatured proteolytic activity. This enzyme was not affected by metal ion, cystein, glutathion or rho-chloromercuribenzoate, but was strongly inhibited by alpha-N-rho-tosyl-L-lysine chloromethyl ketone or soybean-trypsin inhibitor. It was also inhibited by alpha 1-antitrypsin, but not by alpha 2-macroglobulin. This enzyme was confirmed to be immunologically distinct from human plasma, urinary or pancreas kallikrein.

Animals↗
PubMed1979

High concentrations of free kinins and kinin system components in abdominal transudate of a patient with nephrotic syndrome.

High levels of bradykinin (60--80 ng/ml) were found in abdominal transudate from a patient with nephrotic syndrome caused by chronic glomerulonephritis. The abdominal transudate contained neutral kininogenase and its precursor, identified with plasma kallikrein and prekallikrein, respectively, as well as both forms of kininogen, the low-molecular-weight form predominating. The abdominal transudate was characterized also by very low kininase activity and low levels of alpha 1-antitrypsin (0.46 g/l) and alpha 2-macroglobulin. Large amounts of very low density lipoproteins were present in the transudate. Despite the difference in total protein content between the abdominal transudate and the patient's serum (4.3 g/l and 48 g/l, respectively) their protein fraction composition was similar. The data obtained suggest that bradykinin is important in maintenance of long-lasting blood vessel hyperpermeability, which, in turn, is a driving force in the pathogenesis of refractory nephrotic edema.

Adolescent↗
PubMed1978

The role of kininogenases, kinin formation and kininogenase inhibition in post traumatic shock and related conditions.

The kinin system has for a long time been considered to play a role in the pathophysiology of trauma, particularly in blood pressure changes and in inflammatory effects. Recent findings necessitate a revision of this view. It is now necessary to differentiate between two kinin systems: 1. the plasma kallikrein-HMW kininogen-kinin-system, which besides forming kinin acts decisively in Hageman Factor activation, clotting and fibrinolysis; 2. the glandular and tissue kallikrein-LMW kininogen-kinin-system which is to our present day knowledge primarily involved in kinin formation. Kinins exert a variety of actions. By interfering with angiotensin II formation, kinins may contribute to blood pressure regulation. By enhancing cellular glucose uptake and/or metabolism, they regulate partly energy production. In post traumatic states death is preceded by a severe depletion of various factors of the system and an almost total loss of kinin forming capacity. Severity and time course of these phenomena suggest that early institution of direct (Trasylol) or indirect (heparins, cortocosteroids) proteinase inhibition, and if necessary a replacement of the lost factors, should be considered.

Blood Pressure↗
PubMed1979

The kinin-forming acid protease system in murine fibroblasts L-929.

Components of an acid protease kinin-forming enzyme system were isolated and purified from the murine fibroblast L-929 cell line grown in stationary cell culture. The enzyme, was purified from the 10,000 g supernatant cell fraction by sequential passage through G-200 Sephadex, hydroxylapatite, DEAE-A50 Sephadex and affinity chromatography columns. The specific activity was determined on a rat plasma kininogen purified on DEAE and G-100 Sephadex columns as assayed for kinin-forming activity on the isolated perfused rat uterus. Both enzyme and substrate showed a single band pattern by disc gel electrophoresis technique. Optimum protease activity was obtained at pH 3.8, and kinin release was both time- and enzyme-dependent at 37 degrees. The molecular weight of the protease and kininogen, estimated on a G-200 Sephadex column, was 39,000 and 115,000 respectively. Two fibroblast kinins were isolated from a mixture of 12,000 g fraction of fibroblast homogenate and rat plasma incubated at 37 degrees, pH 4.0 for 92 hours. The two fibroblast kinins (I, II) were separated and purified on G-25 Sephadex, CM-C50 Sephadex, and Biogel P-4 columns. The purity of the kinins was ascertained by thin layer chromatography. The molecular weight of fibroblast kinin I was estimated to be 1450 with a 14-amino acid composition consisting of AspThrSerProGluGlyAlaVal-LeuTyrPheLysHisArg. Fibroblast kinin II had an estimated molecular weight of 1000 with a 12-amino acid composition that included AspSerProGluGlyAlaLeuTyrLysHisArg. The kinins were relatively rich in arginine and did not contain the bradykinin sequence.

Amino Acids↗
PubMed1979

Isolation and partial characterization of kinin-like peptides formed by acid protease from murine fibroblast L-929.

A kinin-forming acid protease was isolated and purified from a stationary cell culture of murine fibroblasts L-929 (Biochem. Pharmacol. 26: 1187, 1977). The enzyme formed kinins at an optimal pH of 4.0 from Murphy-Sturm lymphosarcoma tissue and rat plasma kininogen substrate. This study reports on the isolation and partial chemical characterization of two fibroblast kinins. The 12,000 g fraction of L-929 fibroblast homogenates was incubated with rat plasma at 37 degrees, pH 4.0, for 92 hours, and the kinins extracted with ethyl alcohol-p-toluene sulfonic acid. Two fibroblast kinins, FKI and FKII, were separated and purified on the following chromatographic columns: G-25 Sephadex (1 X 115 cm), CM-C50 Sephadex (2.5 X 15 cm), and Biogel P-4 (1 X 115 cm). Kinin activity was bioassayed on the perfused isolated rat uterus preparation. The purity of the kinins was ascertained by thin layer chromatography coupled with dansylation. The estimated molecular weight of FKI was 1450 with a 14-amino acid composition (determined by automatic AA analysis) that included AspThrSerProGluGlyAlaValLeuTyrPheLysHisArg. FKII had an estimated molecular weight of 1000 with a 12-amino acid composition including AspSerProGluGlyAlaLeuTyrLysHisArg. The kinins were relatively rich in arginine and did not contain the bradykinin sequence.

Amino Acids↗
PubMed1979

How do kinins affect vascular tone?

Because kinins affect vascular tone, it is assumed that kinins act directly on smooth muscle. However, a direct interaction is difficult to conceive. Vessels containing smooth muscle are lined by a continuous endothelium with tight junctions. In addition, kinins act on endothelial cells to cause the release of prostaglandin-related substances; possibly through receptors. Furthermore, endothelial cells have a great capacity for hydrolyzing kinins to inactive products. Hence, even invoking active transport, less than 1% of kinins might be expected to reach the first layer of smooth muscle cells. However, kinins may not act directly on smooth muscle as endothelial cells and smooth muscle cells form specialized cell contacts. Myoendothelial junctions occur, and we have shown, in pulmonary arterioles, that smooth muscle cells send large numbers of projections into the cytoplasm of the endothelial cells. In addition, smooth muscle cells attach directly to the abluminal surface of endothelial cells, as do pericytes. Thus, there is a morphologic basis by which kinins can affect tone of smooth muscle without acting directly on smooth muscle cells.

Animals↗
PubMed1975

Interaction of leukocytes and endotoxin with the plasmin and kinin systems.

Leukocytes can generate a substance that, when added to some partially purified human kininogen, is capable of forming kinins. The addition of endotoxin or polystyrene latex particles to the incubated leukocytes doubled the amount of kinin generated. Certain preparations of kininogen, however, failed to allow kinin formation by the leukocytes. No evidence could be found that an activator of prekallikrein or a kallikrein was present in the granulocyte preparations. However, the addition of highly purified plasminogen to inactive kininogen preparations restored their ability to generate kinins in the presence of leukocytes. All the kininogen preparations that allowed kinin formation when incubated with leukocytes contained plasminogen. These data suggest that a plasminogen activator is present on the leukocyte surface. This activator activates plasminogen to form plasmin which in turn acts on kininogen to release a kinin and thus provides a mechanism for the formation of kinins in inflammatory exudates and during endotoxemia.

Endotoxins↗
PubMed1975

Proteases during the growth of Ehrlich ascites tumor. II. The kallikrein-kinin system.

Ascitic fluid and ascites tumor cells from Swiss mice bearing Ehrlich ascites tumor were assayed for components of the kallikrein-kinin system at various times during tumor growth. Changes in component levels were correlated with those in the plasma. Ascitic fluid contained an acetone-activated prekallikrein that increased in concentration during tumor growth and reached peak levels during the 7th-10th day post transplant. No free kinin activity was present in the ascitic fluid. During tumor growth, kininogen levels increased in parallel with prekallikrein levels. The ascitic fluid also contained a kinin-destroying activity that was initially high during the early phase of tumor growth. Tumor cell fractions, prepared by ultracentrifugal techniques, had no kinin-forming activity while possessing kinin-destroying activity that was localized in the soluble protoplasmic protein and nuclear fractions. The kinin-forming activity of the ascitic fluid resembled that of the plasma with respect to pH optima, kinetics of kinin formation, and effect of protease inhibitors. The kininase activity of both ascitic fluid and plasma differed from that of the tumor cell fractions.

Animals↗