Inactivation of alpha 1-proteinase inhibitor and bronchial mucous proteinase inhibitor by cigarette smoke in vitro and in vivo.
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Animals↗
Biomedical subjects
H Carp
Publications and source records attributed to H Carp.
Potential mediator of inflammation. Phagocyte-derived oxidants suppress the elastase-inhibitory capacity of alpha 1-proteinase inhibitor in vitro.
Human polymorphonuclear leukocytes, monocytes, or pulmonary alveolar macrophages, stimulated in vitro by phorbol myristate acetate (PMA), released reactive oxygen species able to suppress the elastase inhibitory capacity (EIC) of human serum. Immunoelectrophoresis using antibodies against alpha(1)-proteinase inhibitor (alpha(1)-Pi) and elastase showed that inactivation of alpha(1)-Pi was responsible for the decreased serum EIC. Treatment of phagocyte-inactivated serum with a reducing agent (dithiothreitol) resulted in significant recovery of EIC, suggesting that alpha(1)-Pi had been oxidatively inactivated. Serum EIC was partially protected by superoxide dismutase or catalase. Hydrogen peroxide alone had no effect on serum EIC. Thus, neither H(2)O(2) nor O(2) (-) alone, but a product of the two, may have oxidatively inactivated alpha(1)-Pi. In support of the foregoing, neutrophils or monocytes from a patient with chronic granulomatous disease failed to produce detectable levels of O(2) (-) after incubation with PMA. These cells also failed to suppress serum EIC. In the case of PMA-stimulated polymorphonuclear leukocytes or monocytes, extracellular myeloperoxidase may have also played a role in alpha(1)-Pi inactivation since serum EIC was partly protected by azide, cyanide, or the depletion of extracellular chloride. Indeed, in a cell-free system consisting of purified myeloperoxidase, a glucose oxidase-H(2)O(2)-generating system, and Cl(-), the EIC of human serum or purified alpha(1)-Pi could also be suppressed. Omission of any single reactant prevented this effect, as did NaN(3) or catalase, suggesting that enzymatically active myeloperoxidase and H(2)O(2) were necessary. Immunoelectrophoresis of myeloperoxidase-inactivated serum showed that, as before, inactivation of alpha(1)-Pi was responsible for the decreased EIC. Treating myeloperoxidase-inactivated serum with dithiothreitol led to significant recovery of EIC, again suggesting that oxidative inactivation of alpha(1)-Pi had occurred. Oxidative inactivation of alpha(1)-Pi in the microenvironment of inflammatory cells, at sites of acute or chronic inflammation, may allow proteases released from these cells to damage adjacent connective tissue components more readily.
Glucose Oxidase↗
Inactivation of bronchial mucous proteinase inhibitor by cigarette smoke and phagocyte-derived oxidants.
Freshly prepared aqueous solutions of cigarette smoke suppressed the elastase inhibitory capacity (EIC) of the acid-stable proteinase inhibitor present in bronchial mucus (BMPi) and human seminal plasma (HUSI-I). Thin-layer gel-immunofiltration analysis of mixtures of smoke-treated BMPi and human leukocyte elastase showed decreased elastase: BMPi complexes, increased uncomplexed BMPi and increased free elastase. Phenolic antioxidants prevented the suppression of the EIC of BMPi or HUSI-I by cigarette smoke. In addition, treatment of BMPi or HUSI-I with chemical oxidants caused a similar suppression of EIC. Furthermore, treatment of BMPi or HUSI-I with the phagocyte-derived oxidizing system, myeloperoxidase + H2O2 + Cl-, suppressed EIC. Finally, the functional activity of BMPi was significantly reduced in tracheal aspirates of human smokers compared to that of nonsmokers. These results support the hypothesis that local inactivation of BMPi in the conducting airways of the lung by inhaled cigarette smoke or by phagocyte-derived oxidants may play a role in the pathogenesis of obstructive lung disease in smokers.
Bronchi↗
Cigarette smoke inhalation decreases alpha 1-antitrypsin activity in rat lung.
Brief inhalation exposure of rats to three or six puffs of cigarette smoke significantly decreases elastase inhibitory capacity per milligram of alpha 1-antitrypsin in lung lavage fluid. This effect is not observed in ozone-tolerant rats and can be reversed by treating the lung lavage fluid from smoke-exposed rats with reducing agents. Samples of human serum obtained immediately after smoking also show decreased elastase inhibitory capacity per milligram of alpha 1-antitrypsin. Again, elastase inhibitory capacity can be restored by treatment with a reducing agent. Cigarette smoking may cause emphysema by inactivating alpha 1-antitrypsin through oxidation.
Animals↗
In vitro suppression of serum elastase-inhibitory capacity by reactive oxygen species generated by phagocytosing polymorphonuclear leukocytes.
Human polymorphonuclear leukocytes (PMN) phagocytosing opsonized antigen-antibody complexes, produce dialyzable species of activated oxygen which are capable of partially suppressing the elastase-inhibiting capacity (EIC) of whole human serum or purified human alpha1-proteinase inhibitor. Serum EIC was partially protially protected by superoxide dismutase, catalase, or mannitol, suggesting that hydroxyl radical, formed by interaction of superoxide radical and hydrogen peroxide, might be responsible for this effect. NaN3 also partly protected EIC, implicating myeloperoxidase-mediated reactions as well. An artificial superoxide rradical-generating system, involving xanthine and xanthine-oxidase, could be substituted for phagocytosing PMN with resultant EIC suppression. These results are consistent with previous demonstrations of the release of potent oxidants by stimulated PMN, as well as earlier studies from our laboratory showing sensitivity of alpha1-proteinase inhibitor to inactivation by oxidants. Oxidative inactivation of proteinase inhibitors in the microenvironment of PMN accumulating at sites of inflammation may allow proteases released from these cells to more readily damage adjacent connective tissue structures.
Catalase↗
Lung injury induced by leukocytic proteases.
Human polymorphonuclear neutrophilic leukocytes (PMNs) contain large amounts of neutral proteases that can degrade elastin, collagen, proteoglycan, and basement membrane. The instillation of one of the purified enzymes (elastase) into dog lungs in vivo causes degradation of elastic fibers and other alveolar septal components and results in anatomic changes similar to those of human pulmonary emphysema. Cigarette smoking is a major risk factor associated with pulmonary emphysema in man. One mechanism for this association may be interference with the regulation of PMN elastase activity by alveolar antiproteases. This possibility is supported by the observation that the oxidizing activity of tobacco smoke inactivates alpha 1-proteinase inhibitor in vitro. Macrophages also secrete an elastolytic protease, albeit at low levels. The short-term exposure of cultured mouse macrophages to cigarette smoke augments the rate of elastase secretion by these cells. Mouse macrophage elastase is not inhibited by alpha 1-proteinase inhibitor or alpha 2-macroglobulin. This unusual property of macrophage elastase may facilitate its attack upon elastin over prolonged intervals despite very low levels of macrophage elastase production. A unified hypothesis of lung injury in pulmonary emphysema is presented, involving both PMN and macrophage elastases and the actions of cigarette smoke. (Am J Pathol 97:111--136, 1979).
Animals↗
Possible mechanisms of emphysema in smokers. In vitro suppression of serum elastase-inhibitory capacity by fresh cigarette smoke and its prevention by antioxidants.
Freshly prepared, aqueous solutions of cigarette smoke suppressed the elastase-inhibitory capacity of human serum. Immunoelectrophoresis of mixtures of aqueous smoke solution, human serum, and pancreatic elastase showed decreased elastase/alpha1-proteinase inhibitor complexes and increased free, active protease. Phenolic antioxidants prevented the suppression of serum elastase-inhibition by cigarette smoke. By contrast, treatment of serum with model oxidants caused a similar suppression of elastase inhibition. These results suggested that emphysema in cigarette smokers might be due, in part, to the local suppression of alpha1-proteinase inhibitor in lung by oxidizing agents present in cigarette smoke.
Depression, Chemical↗
Possible mechanisms of emphysema in smokers: cigarette smoke condensate suppresses protease inhibition in vitro.
To study the possible role of suppression of antiproteases by cigarette smoke in the pathogenesis of pulmonary emphysema in smokers, the following experiments were carried out. Elastin-agarose gels were impregnated with cigarette smoke condensate dissolved in dimethyl sulfoxide or with the solvent alone. This procedure affected neither local pH of the gel nor subsequent physical behavior (diffusion) of antiprotease. Elastases from various sources were then allowed to diffuse through the impregnated gels toward a counter-diffusing sample of antiprotease. The effectiveness of the antiprotease in blocking the enzyme was determined from the extent of elastolysis. The elastin substrates used included beef ligament elastin and dog lung elastin. The enzymes used were porcine pancreatic elastase and pure human leukocyte elastase. The antiproteases tested included human serum, pure human a1-antitrypsin, human bronchopulmonary lavage fluid, and a synthetic chloromethyl ketone inactivator of elastase. The results showed that whole, unfractionated cigarette smoke condensate suppressed all of the antiproteases tested, except for the chloromethyl ketone. These observations are discussed in terms of the protease-pathogenesis model of pulmonary emphysema.
Humans↗
Peri-implantation mouse embryos: an in vitro assay for assessing serum-associated embryotoxicity in women with reproductive disorders.
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Abortion, Habitual↗
Treatment of patients with antiphospholipid antibodies during pregnancy.
Most authors agree upon the causal association between antiphospholipid antibodies [lupus anticoagulant (LAC) and/or anticardiolipin antibodies] and adverse pregnancy outcome. Placental insufficiency, caused by thrombosis, infarction and maldevelopment, is thought to be the main cause of fetal loss in patients with LAC. Therapy given thus far to prevent fetal loss can be divided into (1) immunosuppression by corticosteroids, azathioprine, or intravenous gamma globulin (IVGG), (2) anti-aggregants to overcome imbalance of thromboxane/prostacycline production in patients with LAC, and (3) anticoagulants to neutralize the possible impairment of clotting inhibitor systems. Different therapeutic success rates have been reported by various authors who used the same combination of therapy. We report the results of different therapy regimens in 154 pregnancies in 31 women with LAC. These patients suffered from SLE with LAC or from APLA syndrome and experienced either recurrent miscarriages or thromboembolic phenomena in the past. With no therapy there were seven (6.8%) live births and 95 (93.2%) failures. Various combinations of corticosteroids, anti-aggregants and anticoagulants were used for treatment. Of 52 treated pregnancies, 27 (51.9%) were successful. Sixteen (69.1%) of 23 pregnancies treated by all three modalities ended in live births. Four of these successful pregnancies occurred after failure of treatment by prednisone and anti-aggregants only. In order to minimize osteoporosis caused by the combination of steroids and heparin, we have used warfarin in the second trimester and have lately substituted low molecular weight heparin for heparin. In the absence of a therapeutic schedule predicated on a large prospective study, therapy during pregnancy in patients having LAC should be individualized according to their obstetric and medical history.(ABSTRACT TRUNCATED AT 250 WORDS)
Anticoagulants↗
Immune reproductive failure: effect of nonspecific immunostimulation in mouse model.
There is much evidence that pregnancy loss may be immunologically mediated. Failure of the maternal immune system to actively support the pregnancy may be responsible for its demise. Potentiation of immune functions has been attempted in humans; however, the success of immunotherapy is still not clear. Thus immunotherapy experiments in mouse models are important. Nonspecific immuno-stimulation with complete Freund adjuvant (CFA) was shown in our laboratory to reverse the tendency to fetal loss in the CBA/J X DBA/2J mouse combination. CFA elevates the non-T lymphocyte population, decreases T-cell secreted lymphokines, and enhances macrophage-secreted monokines. However, a relationship between these changes and a beneficial effect of CFA on reproductive performance has to be proved. Information obtained from nonspecific immunopotentiation in the CBA/J-DBA/2J model may contribute the assessment of nonspecific immunotherapy in humans.
Animals↗
Immune features in complete Freund adjuvant-treated CBA/J mouse model.
Immunostimulation with complete Freund adjuvant (CFA) reverses the tendency to fetal loss in the CBA/J x DBA/2J mouse. First attempts to understand the mechanisms underlying this effect were to evaluate phenotypic and functional changes in the lymphocytic cell population after immunopotentiation. We demonstrated that treatment with CFA leads to diminished responses of maternal splenocytes towards paternal alloantigens and this low response cannot be improved with exogenous interleukin-2. Lymphocytes derived from spleen, para-aortic draining lymph nodes and placenta significantly suppress maternal response to paternal antigens. The effect of low fetal resorption rate is followed by marked elevation of asialo GM-1 and HNK-1-positive cells but not followed by any change of the L3T4 or Lyt-2-positive lymphocyte population in either the spleen or in draining lymph nodes. L3T4 and Lyt-2-positive cells have not been found in the placenta. An important feature was marked elevation of Mac-1-positive cells in the placentas of CFA-treated animals. The relevance of these findings to CFA-induced fetal protection is still under investigation.
Animals↗