Plasma-derived Alpha-1 Antitrypsin Research Articles

Recombinant Alpha-1 Antitrypsin-Fc Fusion Protein INBRX-101 in Adults With Alpha-1 Antitrypsin Deficiency: A Phase 1 Study.

Alpha-1 antitrypsin deficiency (AATD) is characterized by low alpha-1 antitrypsin (AAT) levels, predisposing individuals to lung disease. The standard of care, plasma-derived AAT (pdAAT), is delivered as weekly infusions to maintain serum AAT concentrations ≥11µM (≈50% of those in healthy individuals). INBRX-101, a recombinant human AAT-Fc fusion protein, was designed to have a longer half-life and achieve higher AAT levels than pdAAT. In this phase 1 dose-escalation study (N=31), adults with AATD received 1 dose (part 1) or 3 doses (part 2) of 10 (part 1), 40, 80, or 120mg/kg INBRX-101 every 3 weeks (Q3W) via intravenous infusion. The primary endpoint was safety and tolerability. Secondary endpoints were pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of INBRX-101. INBRX-101 was well tolerated. Most treatment-emergent adverse events were grade ≤2. In part 2 (n=18; each dose, n=6), dose-related increases in serum functional AAT (fAAT) were observed; mean fAAT levels remained above the 21 µM target for up to 4 weeks after the final dose in the 120-mg/kg cohort. Antidrug antibodies had no meaningful impact on PK or PD. INBRX-101 was detected in pulmonary epithelial lining fluid (PELF) from all patients assessed (n=11), and PELF fAAT increased after dosing. PK/PD modeling projected steady-state serum fAAT ≥21µM at 120 mg/kg Q3W (average concentration ≈43µM; trough concentration ≈28µM) and Q4W (≈34µM; ≈21µM). The favorable safety profile and ability to maintain serum fAAT levels >21µM with extended-interval dosing, support a phase 2 trial evaluating Q3W and Q4W dosing of INBRX-101.

Recombinant Alpha-1 Antitrypsin as Dry Powder for Pulmonary Administration: A Formulative Proof of Concept.

Alpha-1 antitrypsin (AAT) deficiency is a genetic disorder associated with pulmonary emphysema and bronchiectasis. Its management currently consists of weekly infusions of plasma-purified human AAT, which poses several issues regarding plasma supplies, possible pathogen transmission, purification costs, and parenteral administration. Here, we investigated an alternative administration strategy for augmentation therapy by combining recombinant expression of AAT in bacteria and the production of a respirable powder by spray drying. The same formulation approach was then applied to plasma-derived AAT for comparison. Purified, active, and endotoxin-free recombinant AAT was produced at high yields and formulated using L-leucine and mannitol as excipients after identifying compromise conditions for protein activity and good aerodynamic performances. An oxygen-free atmosphere, both during formulation and powder storage, slowed down methionine-specific oxidation and AAT inactivation. This work is the first peer-reviewed report of AAT formulated as a dry powder, which could represent an alternative to current treatments.

Progress in Alpha-1 Antitrypsin Deficiency: Collaboration as the Foundation of New Knowledge.

As a measure of the importance of alpha-1 antitrypsin deficiency (AATD), 3 papers in this current issue of Chronic Obstructive Pulmonary Diseases: Journal of the COPD Foundation regard AATD. These papers by Choate et al,1 Sieluk et al,2 and Brantly et al3 highlight advances in understanding this important but highly under-recognized condition.4,5 This editorial hopes to frame these diverse papers within current knowledge regarding AATD and to emphasize ways in which these studies reflect a special, collaborative scientific milieu that surrounds AATD.6 The papers respectively compare features of individuals with the PI*ZZ versus PI*SZ genotype,1 present the costs of treating AATD,2 and review available data regarding the efficacy of augmentation therapy for AATD – the intravenous infusion of pooled human plasma-derived alpha-1 antitrypsin (AAT).3

Inhibiting the Inflammatory Injury After Myocardial Ischemia Reperfusion With Plasma-Derived Alpha-1 Antitrypsin: A Post Hoc Analysis of the VCU-α1RT Study

Despite the benefits of reperfusion in limiting myocardial injury, the infarct size continues to expand after reperfusion because of secondary inflammatory injury. Plasma-derived alpha-1 antitrypsin (AAT) inhibits the inflammatory injury in myocardial ischemia and reperfusion. To explore the effects of plasma-derived AAT on the inflammatory response to ischemia-reperfusion injury, we analyzed time-to-reperfusion and enzymatic infarct size estimates in a post hoc analysis of the VCU-α1RT clinical trial (clinicaltrials.gov NCT01936896). Ten patients with ST-segment elevation acute myocardial infarction (STEMI) were enrolled in an open-label, single-arm treatment study of Prolastin C, plasma-derived AAT, at 60 mg/kg infused intravenously within 12 hours of reperfusion. Biomarkers were measured serially over the first 72 hours, and patients were followed clinically for the occurrence of new-onset heart failure, recurrent MI, or death. Twenty patients with STEMI who had been enrolled in previous randomized trials with identical inclusion/exclusion criteria and had been assigned to placebo served as historical controls. Time to percutaneous coronary intervention and time to drug did not significantly differ between groups. AAT-treated patients had a significantly shorter time-to-peak creatine kinase myocardial band (CK-MB) values (525 [480-735] vs. 789 [664-959] minute, P = 0.005) and CK-MB area under the curve (from 1204 [758-2728] vs. 2418 [1551-4289] U·day, P = 0.035), despite no differences in peak CK-MB (123 [30-196] vs. 123 [71-213] U/mL, P = 0.71). A single administration of Prolastin C given hours after reperfusion in patients with STEMI led to a significant shorter time to peak and area under the curve for CK-MB, despite similar peak CK-MB values. These preliminary data support the hypothesis that Prolastin C shortens the duration of the ischemia-reperfusion injury in patients with STEMI.

Alpha-1-antitrypsin in cell and organ transplantation.

Limited availability of donor organs and risk of ischemia‐reperfusion injury (IRI) seriously restrict organ transplantation. Therapeutics that can prevent or reduce IRI could potentially increase the number of transplants by increasing use of borderline organs and decreasing discards. Alpha‐1 antitrypsin (AAT) is an acute phase reactant and serine protease inhibitor that limits inflammatory tissue damage. Purified plasma–derived AAT has been well tolerated in more than 30 years of use to prevent emphysema in AAT‐deficient individuals. Accumulating evidence suggests that AAT has additional anti‐inflammatory and tissue‐protective effects including improving mitochondrial membrane stability, inhibiting apoptosis, inhibiting nuclear factor kappa B activation, modulating pro‐ vs anti‐inflammatory cytokine balance, and promoting immunologic tolerance. Cell culture and animal studies have shown that AAT limits tissue injury and promotes cell and tissue survival. AAT can promote tolerance in animal models by downregulating early inflammation and favoring induction and stabilization of regulatory T cells. The diverse intracellular and immune‐modulatory effects of AAT and its well‐established tolerability in patients suggest that it might be useful in transplantation. Clinical trials, planned and/or in progress, should help determine whether the promise of the animal and cellular studies will be fulfilled by improving outcomes in human organ transplantation.

An oxidation-resistant, recombinant alpha-1 antitrypsin produced in Nicotiana benthamiana.

Proteases and reactive oxygen species (ROS) have long been implicated in playing key roles in host tissue injury at sites of inflammation dominated by macrophage activations and/or neutrophil infiltrations. Imbalances between proteases/antiproteases and ROS/antioxidants are recognized to contribute to amplification of inflammatory-based host tissue injury. This has been especially well-documented in such respiratory tract diseases as chronic obstructive pulmonary disease, cystic fibrosis, and acute respiratory distress syndrome. Inflammation-related protease/ROS disequilibria are further confounded by recognition that proteases can increase ROS by several different mechanisms and that ROS can inactivate proteases. The major human antiprotease, alpha-1 antitrypsin (AAT), is dramatically inactivated by ROS. AAT deficiency is the most prevalent genetic predisposing factor leading to emphysema, a condition treated by replacement infusions of plasma-derived AAT (hAAT) at a cost of up to $200,000 per year per patient. An updated method for production of a plant-made recombinant AAT (prAAT) engineered for enhanced oxidation resistance compared to hAAT is presented. Plant-made recombinant AAT shows comparable antiprotease activity to hAAT, and retains full activity under oxidative conditions that would deactivate hAAT. Additionally, we show that prAAT has similar effectiveness in preventing neutrophil elastase-induced cell death in an in vitro human bronchial epithelial cell culture model. We conclude that prAAT is potentially a "biobetter" AAT product that could be made available to individuals with a wide spectrum of inflammatory disorders characterized by overly aggressive neutrophilic infiltrations.

Epidemiology, Diagnosis and Available Treatment for Alpha 1 Antitrypsin Deficiency-related Emphysema in Europe

Alpha 1 antitrypsin (AAT) deficiency (AATD) is a rare genetic risk factor that predisposes an individual to develop early-onset emphysema. While accurate diagnosis of severe AATD is an important goal of clinical care, a minority of individuals with AATD are diagnosed and lack of awareness about the disease is the major suspected cause for this. Since the 1980s, therapy with human plasma-derived AAT has been the only specific treatment for AATD aiming to slow emphysema progression. The first randomised controlled trial to demonstrate this slowing of disease progression with AAT was the Randomized, placebo-controlled trial of augmentation therapy in Alpha1 Proteinase Inhibitor Deficiency (RAPID) study. The RAPID programme, consisting of the initial trial plus its open-label extension (OLE), is the largest completed clinical study of AAT therapy in AATD and the only trial designed specifically to explore the disease-modifying effect of AAT treatment. The RAPID-OLE data substantiate those of the RAPID trial, establishing the sustained efficacy and good tolerability for AAT treatment, providing evidence that AAT treatment modifies the disease course, and supporting the importance of early intervention.

Enhancement of Alpha 1-antitrypsin Production in Pichia pastoris by Designing and Optimizing Medium Using Elemental Analysis.

Background: Human alpha 1-antitrypsin (AAT) is a monomeric glycosylated protein; it is the potent inhibitor of a whole range of serine proteases and protects tissues against their destructive effects. The human plasma-derived AAT, which is currently used to augment the AAT level in patients, is limited due to high cost and source limitation. Recombinant production of AAT can be considered as a potential alternative. Objectives: This study aims to develop and optimize a new chemically defi ned medium based on an elemental analysis of the yeast Pichia pastoris for an effi cient culture of the recombinant yeast-producing secretory AAT. Materials and Methods: An elemental analysis of Carbon (C), Hydrogen (H), Nitrogen (N), Sulfur (S); CHNS in its abbreviated form, and metallic elements was performed to determine the exact molecular constituent of the P. pastoris. The medium components were selected according to the obtained formula; they were optimized by the response surface methodology (RSM). The grown yeast cell was measured at the end of 18 h glycerol batch culture. The amounts of AAT production and elastase inhibitory capacity (EIC) were measured at the end of three days' methanol feeding. Results: The optimized medium compositions consist of glycerol (40 g.L-1), KH2PO4 (24.78 g.L-1), NaCl, (0.88 g.L-1), MgSO4 .7H2 O (1.95 g.L-1), (NH4 )2 SO4 (22.76 g.L-1), and trace elements (20 mL.L-1). The presented quadratic models show that KH2 PO4 and (NH4)2 SO4, are the most abundant ones in the P. pastoris biomass and have the greatest effect on the cell growth, EIC, and AAT protein production responses. Conclusions: According to the results of this study, it can be concluded that the characterizing cell composition formula could be considered as an appropriate method to design culture media in order to improve cell growth and productivity. Compared to the common P. pastoris chemically defi ned media, FM22 and BSM, production of AAT protein increased by 1.5 and 1.4 times, respectively, in this new medium.

A Preclinical Translational Study of the Cardioprotective Effects of Plasma-Derived Alpha-1 Anti-trypsin in Acute Myocardial Infarction.

The area of myocardial infarction continues to expand for hours after reperfusion. The injured but viable myocardium may be salvaged if the signals leading to cell death are interrupted. Activation of the caspase-1 inflammasome in the heart shortly after ischemia-reperfusion contributes to the final infarct size. Plasma-derived α-1 anti-trypsin (AAT) has shown to inhibit inflammasome formation in vitro and in vivo. To explore the potential translational clinical value of AAT as a therapeutic, we conducted a series of preclinical experiments designed to simulate clinically relevant scenarios. Adult male CD1 mice were used. The left anterior descending coronary artery was ligated for 30 or 75 minutes followed by reperfusion, to explore different severity of ischemic injury. Plasma-derived AAT (Prolastin C) was administered intraperitoneally after reperfusion, without pretreatment, exploring 3 different doses (60, 120, and 180 mg/kg). In a subgroup of mice, we administered Prolastin C with a delay of 30 minutes after reperfusion to simulate the clinical context of delayed administration, and we also used a model of permanent coronary artery ligation without reperfusion. Finally, we tested whether a single dose at reperfusion was sufficient to maintain a benefit in the longer term (7 days). Infarct size was measured by 3 different and independent methodologies: pathology, plasma levels of troponin I, and wall motion abnormalities at echocardiography. Prolastin C given at reperfusion after 30 minutes of ischemia provided a powerful reduction in infarct size (>50% reduction in all methodology used, all P < 0.01) without a clear dose-dependent response. Prolongation of ischemia to 75 minutes nor a delay in treatment by 30 minutes after reperfusion had any negative impact on Prolastin C effects. A single dose given at reperfusion was as effective as multiple daily doses. When given to the mouse without reperfusion, Prolastin C failed to reduce infarct size. Plasma-derived AAT (Prolastin C) given as an adjunct to reperfusion powerfully limits the final infarct size across a wide range of experiments in the mouse reproducing clinically relevant scenarios, such as variable duration of ischemia, delay in administration in the drug, and a large therapeutic index.

115 - Plant-Based Production, Purification, and Characterization of Oxidation-Resistant Alpha-1 Antitrypsin

Alpha-1 antitrypsin (AAT) is an acute phase protease inhibitor. Currently, the only available treatment for patients with COPD caused by AAT deficiency is replacement therapy, requiring weekly infusions of human plasma-derived AAT. While AAT has shown potential when inhaled to treat both emphysema and cystic fibrosis, the oxidation susceptibility of methionine residues at positions 351 and 358 in the reactive site loop have led to difficulties in maintaining AAT activity and stability when aerosolized. Using a novel cucumber mosaic virus-based inducible transient expression system, we have produced a biobetter plant recombinant AAT (prAAT) in Nicotiana benthamiana . This variant replaces the oxidation-susceptible methionine residue at position 358 with a valine residue to increase resistance to oxidation. N. benthamiana plants were vacuum infiltrated as detached leaves with two strains of Agrobacterium tumefaciens : one carrying the biobetter AAT gene and one carrying a gene for the tomato bushy stunt virus p19 viral RNA silencing suppressor driven by a constitutive cauliflower mosaic virus 35S promoter. Leaves were incubated in humidity chambers at 20°C in the dark for 6 days before flash freezing in liquid nitrogen, grinding, and protein extraction in a 20 mM Tris, 150 mM NaCl, and 0.01% (v/v) Tween-80 AAT stability buffer. Purification was achieved using Alpha-1 Antitrypsin Select Affinity Chromatography (GE Healthcare) with a 58.1±8.1% yield of active AAT. Activity of purified AAT was confirmed via a band shift in a Western blot after incubation with excess porcine pancreatic elastase, however, degradation of prAAT was also observed in all purified extracts. Purified prAAT was tested against an analytical standard (Calbiochem) and Prolastin-C (Griffols), a common therapeutic formulation of human AAT, to determine its activity and oxidation resistance. 41±11% of purified prAAT and 71.9±5.5% of Prolastin-C showed activity against porcine pancreatic elastase as determined by a residual elastase activity inhibitory assay. Under oxidation with 48.9 mM H 2 O 2 for 60 minutes at room temperature, prAAT was found to retain 102.8±20.4% of its original anti-elastase activity, while Prolastin-C retained 13.8±5.0% anti-elastase activity and analytical standard AAT retained 11.6±7.5% anti-elastase activity. Future work will include determinations of oxidation resistance to OCl – /HOCl and development of more optimal isolation and purification processes.

Trials and Tribulations: An Industry Perspective on Conducting Registrational Trials in Alpha-1 Antitrypsin Deficiency.

Registrational trials in rare and orphan diseases present complexities related to the identification of subjects, recruitment, logistical hurdles incumbent with far-flung study sites, and end points that are often less well defined than are those used in more common illnesses. Alpha-1 antitrypsin deficiency is an orphan disease of genetic origin that carries the additional challenges of variable penetration and slow disease progression. Registrational trials of augmentation therapy using plasma-derived alpha-1 antitrypsin carry all of the above-noted burdens, as well as competition from commercially available augmentation therapy in many countries.

Recombinant production of native human α-1-antitrypsin protein in the liver HepG2 cells.

Alpha-1 antitrypsin (A1AT) deficiency is associated with emphysema and liver disease. Only plasma-derived A1AT protein is available for augmentation therapy. Recombinant A1AT (recA1AT) protein expressed in various types of available hosts are either non-glycosylated or aberrantly glycosylated resulting into reduced stability and biological activity. To overcome these limitations, we have used the human liver HepG2 cell line to produce recA1AT protein. HepG2 cells were transfected by A1AT cDNA and cell populations were generated that stably overexpressed A1AT protein. Real-time RT-PCR and rocket immunoelectrophoresis of cell culture supernatants indicated that the transfection resulted more than two-fold increase in A1AT production compared to that of control parental cells. Immunoblot analysis showed that both plasma and HepG2-produced A1AT proteins have identical molecular weight in either glycosylated or deglycosylated form. Partial digestion with PNGase F indicated that the three N-glycosylation sites of recA1AT, like the native A1AT protein in plasma, are occupied. Recombinant A1AT also like the native A1AT was thermostable and could efficiently inhibit trypsin proteolytic activity against BSA and BAPNA chromogenic substrate. The recombinant HepG2 cells cultured in media containing B27 serum free supplement released recA1AT at the same level as in the serum containing media. RecA1AT production in HepG2 cells grown under serum free condition at a large scale could provide a reliable source of the native protein suitable for therapeutic use in human.

Additional N-glycosylation in the N-terminal region of recombinant human alpha-1 antitrypsin enhances the circulatory half-life in Sprague-Dawley rats.

Glycosylation affects the circulatory half-lives of therapeutic proteins. However, the effects of an additional N-glycosylation in the unstructured region or the loop region of alpha-1 antitrypsin (A1AT) on the circulatory half-life of the protein are largely unknown. In this study, we investigated the role of an additional N-glycosylation site (Q4N/D6T, Q9N, D12N/S14T, A70N, G148T, R178N, or V212N) to the three naturally occurring N-glycosylation sites in human A1AT. A single-dose (445μg/kg) pharmacokinetic study using male Sprague-Dawley rats showed that, among the seven recombinant A1AT (rA1AT) mutants, Q9N and D12N/S14T showed the highest serum concentration and area under the curve values, as well as similar circulatory half-lives that were 2.2-fold higher than plasma-derived A1AT and 1.7-fold higher than wild-type rA1AT. We further characterized the Q9N mutant regarding the N-glycan profile, sialic acid content, protease inhibitory activity, and protein stability. The results indicate that an additional N-glycosylation in the flexible N-terminal region increases the circulatory half-life of rA1AT without altering its protease inhibitory activity. Our study provides novel insight into the use of rA1AT for the treatment of emphysema with an increased injection interval relative to the clinically used plasma-derived A1AT.

The Diagnosis and Management of Alpha-1 Antitrypsin Deficiency in the Adult.

Background: The diagnosis and clinical management of adults with alpha-1 antitrypsin deficiency (AATD) have been the subject of ongoing debate, ever since the publication of the first American Thoracic Society guideline statement in 1989.1 In 2003, the "American Thoracic Society (ATS)/European Respiratory Society (ERS) Statement: Standards for the Diagnosis and Management of Individuals with Alpha-1 Antitrypsin Deficiency" made a series of evidence-based recommendations, including a strong recommendation for broad-based diagnostic testing of all symptomatic adults with chronic obstructive pulmonary disease (COPD).2 Even so, AATD remains widely under-recognized. To update the 2003 systematic review and clinical guidance, the Alpha-1 Foundation sponsored a committee of experts to examine all relevant, recent literature in order to provide concise recommendations for the diagnosis and management of individuals with AATD. Purpose: To provide recommendations for: (1) the performance and interpretation of diagnostic testing for AATD, and (2) the current management of adults with AATD and its associated medical conditions. Methods: A systematic review addressing the most pressing questions asked by clinicians (clinician-centric) was performed to identify citations related to AATD that were published since the 2003 comprehensive review, specifically evaluating publications between January 2002 and December 2014. Important, more recent publications were solicited from the writing committee members as well. The combined comprehensive literature reviews of the 2003 document and this current review comprise the evidence upon which the committee's conclusions and recommendations are based. Results: Recommendations for the diagnosis and management of AATD were formulated by the committee. Conclusions: The major recommendations continue to endorse and reinforce the importance of testing for AATD in all adults with symptomatic fixed airflow obstruction, whether clinically labeled as COPD or asthma. Individuals with unexplained bronchiectasis or liver disease also should be tested. Family testing of first-degree relatives is currently the most efficient detection technique. In general, individuals with AATD and emphysema, bronchiectasis, and/or liver disease should be managed according to usual guidelines for these clinical conditions. In countries where intravenous augmentation therapy with purified pooled human plasma-derived alpha-1 antitrypsin is available, recent evidence now provides strong support for its use in appropriate individuals with lung disease due to AATD.

Effects of Prolastin C (Plasma-Derived Alpha-1 Antitrypsin) on the Acute Inflammatory Response in Patients With ST-Segment Elevation Myocardial Infarction (from the VCU-Alpha 1-RT Pilot Study)

Alpha-1 antitrypsin (AAT) has broad anti-inflammatory and immunomodulating properties in addition to inhibiting serine proteases. Administration of human plasma-derived AAT is protective in models of acute myocardial infarction in mice. The objective of this study was to determine the safety and tolerability of human plasma-derived AAT and its effects on the acute inflammatory response in non-AAT deficient patients with ST-segment elevation myocardial infarction (STEMI). Ten patients with acute STEMI were enrolled in an open-label, single-arm treatment study of AAT at 60mg/kg infused intravenously within 12hours of admission and following standard of care treatment. C-reactive protein (CRP) and plasma AAT levels were determined at admission, 72hours, and 14days, and patients were followed clinically for 12weeks for the occurrence of new onset heart failure, recurrent myocardial infarction, or death. Twenty patients with STEMI enrolled in previous randomized trials with identical inclusion and/or exclusion criteria, but who received placebo, served as historical controls. Prolastin C was well tolerated and there were no in-hospital adverse events. Compared with historical controls, the area under the curve of CRP levels was significantly lower 14days after admission in the Prolastin C group (75.9 [31.4 to 147.8] vs 205.6 [78.8 to 410.9] mg/l, p= 0.048), primarily due to a significant blunting of the increase occurring between admission and 72hours (delta CRP+1.7 [0.2 to 9.4] vs+21.1 [3.1 to 38.0] mg/l, p= 0.007). Plasma AAT levels increased from admission (149 [116 to 189]) to 203 ([185to 225] mg/dl) to 72hours (p=0.005). In conclusion, a single administration of Prolastin C in patients with STEMI is well tolerated and is associated with a blunted acute inflammatory response.

Using antisense technology to develop a novel therapy for α-1 antitrypsin deficient (AATD) liver disease and to model AATD lung disease.

Alpha-1 antitrypsin (AAT) is a serum protease inhibitor that belongs to the serpin superfamily. Mutations in AAT are associated with α-1 antitrypsin deficiency (AATD), a rare genetic disease with two distinct manifestations: AATD lung disease and AATD liver disease. AATD lung disease is caused by loss-of-function of AAT and can be treated with plasma-derived AAT. AATD liver disease is due to the aggregation and retention of mutant AAT protein in the liver; the only treatment available for AATD liver disease is liver transplantation. Here we demonstrate that antisense oligonucleotides (ASOs) targeting human AAT efficiently reduce levels of both short and long human AAT transcript in vitro and in transgenic mice, providing a novel therapy for AATD liver disease. In addition, ASO-mediated depletion of mouse AAT may offer a useful animal model for the investigation of AATD lung disease.

10: Recombinant alpha-1 antitrypsin-Fc (AAT-Fc) inhibits candida-induced IL 1β secretion from human CD14 monocytes: comparison to plasma-derived AAT and caspase 1 inhibition

Although often studied for its ability to inhibit neutrophil elastase, alpha-1 antitrypsin (AAT) has broad anti-inflammatory properties not related to its anti-protease activity. For example, monotherapy of mice with human plasma-derived AAT prevents pancreatic islet beta cell allograft rejection, the incidence of diabetes in the NOD mouse, DSS colitis, ischemia–reperfusion injury in the heart and graft versus host disease. Clinical trials are being conducted using AAT to treat late onset diabetes mellitus and graft versus host disease. However, AAT is purified from pooled human plasma and since the treatment dose is 60 mg/kg (or higher), plasma-derived AAT dosing requires intravenous infusion. In addition, human plasma carries the risk of infection with unknown viruses. Therefore, we produced recombinant human AAT as an Fc fusion protein and studied its properties in various animal models of systemic and local inflammation. We compared AAT-Fc with plasma-derived AAT. Plasma-derived or AAT-Fc reduced monosodium urate crystal acute knee joint arthritis; however, AAT-Fc at 2 mg/kg intraperitoneally was as effective as 80 mg/kg of plasma AAT (40-fold less). We next studied the ability of AAT to reduce IL1 β secretion from human blood monocytes stimulated with heat-killed Candida albicans in vitro. Although plasma-derived AAT reduced Candida-induced IL1b secretion at 500–1000 μg/mL by 50%, AAT-Fc was as effective at μg/mL. At 25 μg/mL, AAT-Fc reduced IL1 β secretion by 55% compared to 44% using 10 μM of a specific caspase1 inhibitor. The intracellular levels of IL1 β following Candida stimulation were also reduced by AAT- Fc, for example, 51% inhibition at 12 mg/mL, suggesting that AAT-Fc reduces IL-1 β synthesis as well as secretion. In contrast to reducing IL1 β , AAT-Fc at 12 mg/mL induces the release of the IL-1receptor antagonist from monocytes. Without being derived from human plasma, recombinant AAT-Fc is safe and due to its high specific activity, may be administered subcutaneously.

Structural characterization of recombinant alpha-1-antitrypsin expressed in a human cell line

Human alpha-1-antitrypsin (A1PI) is a plasma protein with the function of protecting lung tissues from proteolytic destruction by enzymes from inflammatory cells. A1PI deficiency is an inherited disorder associated with pulmonary emphysema and a higher risk of chronic obstructive pulmonary disease (COPD). Here we present the structural characterization of a recombinant form of human A1PI (Hu-recA1PI) expressed in the human PER.C6 cell line using an array of analytical and biochemical techniques. Hu-recA1PI had the same primary structure as plasma-derived A1PI (pd-A1PI) except reduced N-terminal heterogeneity. The secondary and tertiary structures were indistinguishable from pd-A1PI. Like pd-A1PI, Hu-recA1PI was modified by N-linked glycosylation on N46, N83, and N246. Unlike pd-A1PI, most glycans on recA1P1 were core fucosylated via α(1–6) linkage. In addition, significantly higher amounts of tri- and tetraantennary glycans were observed. These differences in glycosylation contributed to the apparent higher molecular weight and lower isoelectric point (pI) of Hu-recA1PI than pd-A1PI. Hu-recA1PI contained both α(2-3)- and α(2-6)-linked sialic acids and had very similar sialylation levels as pd-A1PI. Hu-recA1PI glycans were differentially distributed, with N46 containing mostly biantennary glycans, N83 containing primarily tri- and tetraantennary glycans, and N247 containing exclusively biantennary glycans.

Novel Therapeutic Uses of Alpha-1 Antitrypsin: A Window to the Future

Alpha-1 antitrypsin, a potent serine protease inhibitor, has been used as augmentation therapy in patients with alpha-1 antitrypsin deficiency for many years. Recent research into the diverse anti-inflammatory, immune-modulatory and tissue-protective actions of alpha-1 antitrypsin has raised the possibility of broadening the therapeutic spectrum of alpha-1 antitrypsin to include diseases other than alpha-1 antitrypsin deficiency. The purpose of the workshop was to summarize the results of basic investigations and, if available, clinical studies in which the effects of alpha-1 antitrypsin were explored in relation to clinical conditions that are not associated with alpha-1 antitrypsin deficiency. Included among these are type 1 diabetes, cell/organ rejection, viral infection, cystic fibrosis, bronchiectasis/COPD, heart failure, Crohn's disease and connective tissue diseases. Although the therapeutic utility of alpha-1 antitrypsin in these conditions remains to be established, the existing data suggest that this protein eventually will become a treatment option in several diseases some of which are not rare. At present, only human plasma-derived alpha-1 antitrypsin is available for clinical use. Given the limited supply and the potential for extended use of this product, there will be a need for new formulations of alpha-1 antitrypsin in the future. Therefore, the prospect of finding new sources and airway delivery methods of alpha-1 antitrypsin were also discussed. The presentations at the meeting addressed the scientific basis for new clinical applications of alpha-1 antitrypsin and the regulatory requirements needed to bring this therapeutic protein to a wider range of patient populations.

α1‐Antitrypsin in Fibromyalgia: Results of a Randomized, Placebo‐Controlled, Double‐Blind and Crossover Pilot Trial

To assess clinical effect of a human plasma-derived alpha-1 antitrypsin (AAT) concentrate in reducing pain severity of patients with fibromyalgia (FM). Thirteen subjects with FM completed a randomized, double-blind, placebo-controlled, crossover study which consisted of 9 weeks trial of AAT or placebo with a washout period of 6 weeks. Primary efficacy endpoint was change on pain severity score, assessed by a daily visual analogue scale (VAS) for pain. Other outcome measures included a tender point score, the Fibromyalgia Impact Questionnaire, (FIQ), the Medical Outcomes Study Short Form 36 (SF-36), the Health Assessment Questionnaire Disability Index (HAQ-DI), the Hospital Anxiety and Depression Scale (HADS) and tiredness score evaluated by VAS. No statistically significant differences were observed in either pain severity or other secondary outcome measures in either of the treatment groups, or between treatment groups in either of the treatment periods. No carryover or order of intervention effect was observed from one treatment to the other. Both investigational interventions were generally well tolerated, and vital signs during the drug infusions were within the respective normal ranges. Treatment with a human plasma-derived AAT concentrate did not demonstrate significant improvement over placebo on reducing pain severity and other symptoms of FM. Further research should examine other FM subpopulations and drug doses.