New process for purifying high purity α1-antitrypsin from Cohn Fraction IV by chromatography: A promising method for the better utilization of plasma

Augmentation therapy with alpha 1-antitrypsin: present and future of production, formulation, and delivery

Alpha 1-antitrypsin is one of the first protein therapeutics introduced on the market - more than 30 years ago - and, to date, it is indicated only for the treatment of the severe forms of a genetic condition known as alpha-1 antitrypsin deficiency. The only approved preparations are derived from plasma, posing potential problems associated with its limited supply and high processing costs. Moreover, augmentation therapy with alpha 1-antitrypsin is still limited to intravenous infusions, a cumbersome regimen for patients. Here, we review the recent literature on its possible future developments, focusing on i) the recombinant alternatives to the plasma-derived protein, ii) novel formulations, and iii) novel administration routes. Regulatory issues and the still unclear noncanonical functions of alpha 1-antitrypsin - possibly associated with the glycosylation pattern found only in the plasma-derived protein - have hindered the introduction of new products. However, potentially new therapeutic indications other than the treatment of alpha-1 antitrypsin deficiency might open the way to new sources and new formulations.

Methods of Purification and Application Procedures of Alpha1 Antitrypsin: A Long-Lasting History

The aim of the present report is to review the literature addressing the methods developed for the purification of alpha1-antitrypsin (AAT) from the 1950s to the present. AAT is a glycoprotein whose main function is to protect tissues from human neutrophil elastase (HNE) and other proteases released by neutrophils during an inflammatory state. The lack of this inhibitor in human serum is responsible for the onset of alpha1-antitrypsin deficiency (AATD), which is a severe genetic disorder that affects lungs in adults and for which there is currently no cure. Being used, under special circumstances, as a medical treatment of AATD in the so-called “replacement” therapy (consisting in the intravenous infusion of the missing protein), AAT is a molecule with a lot of therapeutic importance. For this reason, interest in AAT purification from human plasma or its production in a recombinant version has grown considerably in recent years. This article retraces all technological advances that allowed the manufacturers to move from a few micrograms of partially purified AAT to several grams of highly purified protein. Moreover, the chronic augmentation and maintenance therapy in individuals with emphysema due to congenital AAT deficiency (current applications in the clinical setting) is also presented.

Identification of unexplored substrates of the serine protease, thrombin, using N-terminomics strategy

The function and regulation of thrombin is a complex as well as an intriguing aspect of evolution and has captured the interest of many investigators over the years. The reported substrates of thrombin are coagulation factors V, VIII, XI, XIII, protein C and fibrinogen. However, these may not be all the substrate of thrombin and therefore its functional role(s), may not have been completely comprehended. The purpose of our study was to identify hitherto unreported substrates of thrombin from human plasma using a N-terminomics protease substrate identification method. We identified 54 putative substrates of thrombin of which 12 are already known and 42 are being reported for the first time. Amongst the proteins identified, recombinant siglec-6 and purified serum alpha-1-acid glycoprotein were validated by cleavage with thrombin. We have discussed the probable relevance of siglec-6 cleavage by thrombin in human placenta mostly because an upregulation in the expression of siglec-6 and thrombin has been reported in the placenta of preeclampsia patients. We also speculate the role of alpha-1-acid glycoprotein cleavage by thrombin in the acute phase as alpha-1-acid glycoprotein is known to be an inhibitor of platelet aggregation whereas thrombin is known to trigger platelet aggregation.

Expression, Purification, and Characterization of Recombinant Human α1-Antitrypsin Produced Using Silkworm-Baculovirus Expression System

Human α₁-antitrypsin (AAT) is the most abundant serine proteinase inhibitor (serpin) in the human plasma. Commercially available AAT for the medications of deficiency of α₁-antitrypsin is mainly purified from human plasma. There is a high demand for a stable and low-cost supply of recombinant AAT (rAAT). In this study, the baculovirus expression vector system using silkworm larvae as host was employed and a large amount of highly active AAT was recovered from the silkworm serum (~ 15 mg/10 ml) with high purity. Both the enzymatic activity and stability of purified rAAT were comparable with those of commercial product. Our results provide an alternative method for mass production of the active rAAT in pharmaceutical use.