Activity Of Alpha 1-antitrypsin Research Articles

Electrophoretic mobility, concentration, and activity of alpha 1-antitrypsin in serum of patients undergoing bone-marrow transplantation.

We have observed an electrophoretically abnormal, nonfunctional species of alpha 1-antitrypsin in serum from patients who were receiving bone-marrow transplants for treatment of leukemia or aplastic anemia. Three of four patients in whose serum this protein appeared died soon after; the fourth recovered, and the disappearance of the abnormal alpha 1-antitrypsin paralleled his recovery. This suggests that the inability to maintain functional activity of alpha 1-antitrypsin predisposes patients to life-threatening complications during recovery from bone-marrow transplants.

Alpha 1-antitrypsin in cerebrospinal fluid of patients with neurologic diseases.

Proteases and their inhibitors have been implicated in the pathogenesis of neuroimmunologic diseases, particularly multiple sclerosis (MS). We measured the immunochemical level and functional activity of alpha 1-antitrypsin (AAT) in cerebrospinal fluid (CSF) and serum in patients with MS and other neurologic diseases. Increases in the immunochemical level of AAT in CSF correlated directly with disturbances in the blood-brain barrier, as reflected by the ratio of albumin in CSF to that in serum. The AAT activity in CSF directly correlated with the immunochemical level when all patients were compared. However, the AAT activity in patients with inflammatory diseases tended to be decreased relative to the immunochemical level, suggesting inactivation of AAT in these disorders. The AAT activity was not significantly altered in patients with MS, despite reports of increased protease activity in active MS.

Standardized automated assay for functional alpha 1-antitrypsin.

We describe an enzymic assay for the functional activity of alpha 1-antitrypsin, in which tosyl-Gly-Pro-Lys-p-nitroanilide acetate (Chromozym PL) is the trypsin substrate. For the indicating reaction, the concentration of substrate is about double the Km of its reaction with trypsin. This assay is an improvement over reactions involving N-alpha-benzoyl-DL-arginine p-nitroanilide as substrate, the solubility of which in water is less than the Km of its reaction with trypsin. The assay is standardized in terms of active sites of trypsin inhibited per liter of serum, with p-nitrophenyl-p'-guanidinobenzoate as the active site titrant. The results agreed well with those by an immunonephelometric assay for alpha 1-antitrypsin (r = 0.953). The within-run and run-to-run precision was approximately 3%. The results of the assay varied linearly with alpha 1-antitrypsin concentration from 0 to 60 mumol/L of serum. The minimum sample size was 50 microL, and analysis of 24 samples took less than 20 min.

Screening test for alpha 1-antitrypsin in dried-blood specimens.

We describe a fluorescent spot test for detecting alpha 1-antitrypsin activity in dried-blood specimens. The eluate of a blood disc is mixed with carbobenzoxy-L-arginine-7-amino-4-methylcoumarin amide and trypsin at the appropriate pH. In the absence of alpha 1-antitrypsin, aminomethylcoumarin, a strongly fluorescent compound, is released. The reaction mixture, when spotted on chromatography paper and viewed under ultraviolet light, exhibits a bright fluorescence only in the case of specimens with alpha 1-antitrypsin deficiency. alpha 1-Antitrypsin activity so estimated correlated well with quantitative assays of dried-blood spots and serum. The procedure is simple and inexpensive, and has the potential for use as a screening test.

A matched-pair study of the leukocyte elastase-like activity in normal persons and in emphysematous patients with and without alpha 1-antitrypsin deficiency.

The elastase-like activities in whole cell extracts of neutrophilic polymorphonuclear leukocytes of 10 emphysematous patients with alpha 1-antitrypsin deficiency (PiZ) and of 7 subjects with alpha 1-antitrypsin deficiency (PiZ or PiSZ) without emphysema were the same as the activities of healthy nondeficient subjects (PiMM) matched according to age, sex, and smoking history. In 16 emphysematous patients without alpha 1-antitrypsin deficiency (PiMM) however, the leukocyte elastase-like activity tended to be higher than that of normal control subjects. We concluded that in persons with alpha 1-antitrypsin deficiency, the leukocyte elastase-like activity is not a deciding factor in the development of emphysema. In persons without alpha 1-antitrypsin deficiency, however, the leukocyte elastase-like activity may be a contributing factor in the development of this disease. Variations in specific anti-leukocyte-elastase-like activity of alpha 1-antitrypsin, which might play a role in the pathogenesis of emphysema, were not found.

Cigarette Smoking Induces Functional Antiprotease Deficiency in the Lower Respiratory Tract of Humans

Current concepts of the pathogenesis of emphysema suggest that it results from an imbalance of elastase and antielastase activity within the alveolar structures. Although emphysema that is associated with hereditary deficiency of serum alpha 1-antitrypsin conforms to this scheme, the major risk factor in the more common form of emphysema is cigarette smoking. A study was designed to evaluate the premise that cigarette smoking may be associated with an acquired, functional defect in lung alpha 1-antitrypsin. Determination of the antielastase activity of alpha 1-antitrypsin obtained from the lungs of smoking and nonsmoking individuals revealed a nearly twofold reduction in the functional activity of this elastase inhibitor in the lungs of cigarette smokers. These data suggest that cigarette smokers may lose some of the normal antielastase protective screen of the lower respiratory tract, making them more vulnerable to destructive lung disease.

Albumin microspheres as carrier of an inhibitor of leukocyte elastase: potential therapeutic agent for emphysema.

Methods are described for the covalent attachment of succinoyl-Ala-Ala-Pro-ValCH2Cl, an active site-directed inhibitor of human leukocyte elastase (EC 3.4.21.11), to microspheres of human albumin. The insertion of side arms of various lengths revealed that maximum inhibition of this enzyme was obtained when the spacer arm was at least 24.3 A in length. Approximately 30 molecules of the inhibitor could be attached to each molecule of albumin. Such derivatized microspheres were capable of inhibiting approximately one mole of elastase per mole of albumin, which is comparable to the inhibitory activity of alpha 1-antitrypsin. Experiments in vivo in which rats were injected intravenously with radiolabeled microspheres to which the inhibitor had been attached showed a rapid and exclusive uptake by the lungs. About 40--50% of the injected microspheres subsequently remained in the lungs with a half-life of approximately 17 days. These derivatized microspheres thus appear to offer promise as a therapeutic agent for emphysema.

Alpha 1-antitrypsin activity of perilymph. Occurrence during progression of otospongiosis.

Previous studies by the Adams method demonstrated a strong correlation between hydrolytic enzyme activity of perilymph and progression of bone conduction loss two years preceding stapedectomy. Alpha 1-Antitrypsin was chosen since its activity can be very precisely measured by a radical immunodiffusion technique and since it is one of the enzymes identified in perilymph of patients with active otospongiosis. Samples of 3 mul to 5 mul of perilymph removed during 103 stapedectomies and samples of known alpha 1-trypsin activity were placed on slides coated with alpha 1-antitrypsin serum. The zone of diffusion was stained and measured after 38 hours of incubation. Antitrypsin values were lowest in 24 cases, two with no preoperative bone conduction progression, three with moderate progression of 10 to 15 dB, and 19 with rapid progression of more than 20 dB. They were highest in 36 cases with no progression, and in one case with moderate progression. This study confirms previous reports on the enzymatic activity in otospongiotic disease.