Diagnosis and augmentation therapy for alpha-1 antitrypsin deficiency: current knowledge and future potential

Streamlined purification of recombinant Alpha-1 antitrypsin from CHO cell culture using integrated chromatography within a single unit operation

Recombinant Alpha-1 Antitrypsin (A1AT) produced from CHO cell culture is a promising alternative to the commercially available drug, which is derived from the limited supply of blood plasma. By developing and optimizing the purification strategy through the combination of appropriate chromatography mechanisms and buffer conditions, we successfully achieved end-to-end purification of A1AT from cell culture supernatant to the final drug substance leveraging integrated chromatography within a single unit operation, with quality comparable or even superior to commercial drugs. With comparable processing time and buffer consumption, the proposed approach-integrating 2 anion exchange chromatography (AEX) and 1 hydrophobic charge induction chromatography (HCIC) -achieved 99.9 % purity and 27 ppm host cell protein (HCP), compared to 96.9 % purity and 2860 ppm HCP using the conventional method with a single AEX column in batch mode. Compared to the conventional approach of using one column per unit operation, this streamlined process can increase the productivity of A1AT by reducing unit operations and eliminating the need for sample holding and conditioning between chromatographic steps, thereby potentially reducing the manufacturing cost of recombinant A1AT produced from CHO cell culture.

Role of alpha-1 antitrypsin in Bruch's membrane integrity

Alpha-1 antitrypsin (AAT) is a serine protease inhibitor that plays a crucial role in maintaining extracellular matrix integrity. Studies suggest that AAT augmentation therapy may benefit multiple eye diseases, including age-related macular degeneration (AMD). However, the function of endogenous AAT in the eye remains unclear. Here we used genetic knockout mice to study the role of AAT in eye health. We show that loss of AAT results in Bruch's membrane (BrM) thickening driven in part by increased laminin deposition with a concomitant decrease in collagen and elastin, which are two other critical BrM components. Interestingly, BrM remodeling due to excess extracellular protease activity reduced the age-related deposition at the BrM of apolipoprotein E, while increasing complement factor H and lowering secretion of the proangiogenic vascular endothelial growth factor. Despite these changes, the phagocytic function of the retinal pigment epithelium was not affected nor was the expression of genes that partake in photoreceptor cell metabolism. Consistent with loss of AAT resulting in changes that should alleviate AMD pathologies, human AMD donor eyes exhibited lower AAT expression levels in the BrM/choroid layer when compared to healthy donor eyes. Together, the study provides insight into AAT's function and its potential involvement in AMD.

Recommendations for the diagnosis and treatment of alpha-1 antitrypsin deficiency

Alpha-1 antitrypsin deficiency (AATD) is a relatively rare genetic disorder, inherited in an autosomal codominant manner, that results in reduced serum AAT concentrations, with a consequent reduction in antielastase activity in the lungs, as well as an increased risk of diseases such as pulmonary emphysema, liver cirrhosis, and necrotizing panniculitis. It results from different mutations in the SERPINA1 gene, leading to changes in the AAT glycoprotein, which can alter its concentration, conformation, and function. Unfortunately, underdiagnosis is quite common; it is possible that only 10% of cases are diagnosed. The most common deficiency is in the Z variant, and it is estimated that more than 3 million people worldwide have combinations of alleles associated with severe AATD. Serum AAT concentrations should be determined, and allelic variants should be identified by phenotyping or genotyping. Monitoring lung function, especially through spirometry, is essential, because it provides information on the progression of the disease. Although pulmonary densitometry appears to be the most sensitive measure of emphysema progression, it should not be used in routine clinical practice to monitor patients. In general, the treatment is similar to that indicated for patients with COPD not caused by AATD. Exogenous administration of purified human serum-derived AAT is the only specific treatment approved for AATD in nonsmoking patients with severe deficiency (serum AAT concentration of < 57 mg/dL or < 11 µM), with evidence of functional loss above the physiological level.

mRNA therapies: Pioneering a new era in rare genetic disease treatment

Rare genetic diseases, often referred to as orphan diseases due to their low prevalence and limited treatment options, have long posed significant challenges to our medical system. In recent years, Messenger RNA (mRNA) therapy has emerged as a highly promising treatment approach for various diseases caused by genetic mutations. Chemically modified mRNA is introduced into cells using carriers like lipid-based nanoparticles (LNPs), producing functional proteins that compensate for genetic deficiencies. Given the advantages of precise dosing, biocompatibility, transient expression, and minimal risk of genomic integration, mRNA therapies can safely and effectively correct genetic defects in rare diseases and improve symptoms. Currently, dozens of mRNA drugs targeting rare diseases are undergoing clinical trials. This comprehensive review summarizes the progress of mRNA therapy in treating rare genetic diseases. It introduces the development, molecular design, and delivery systems of mRNA therapy, highlighting their research progress in rare genetic diseases based on protein replacement and gene editing. The review also summarizes research progress in various rare disease models and clinical trials. Additionally, it discusses the challenges and future prospects of mRNA therapy. Researchers are encouraged to join this field and collaborate to advance the clinical translation of mRNA therapy, bringing hope to patients with rare genetic diseases.

Alpha-1 antitrypsin deficiency

Alpha-1 antitrypsin deficiency (AATD) is a rare hereditary condition caused by decreased plasma and tissue levels of alpha-1 antitrypsin (AAT) that can lead to serious lung and liver disease in children and adults. AATD patients face challenges such as under diagnosis, clinical variability, and limited treatment options for liver disease. Early detection and biomarkers for predicting outcomes are needed to improve patient outcome. Currently, the only approved pharmacological therapy is augmentation therapy, which can delay the progression of emphysema. However, alternative strategies such as gene therapy, induced pluripotent stem cells, and prevention of AAT polymerization inside hepatocytes are being investigated. This review aims to summarize and update current knowledge on AATD, identify areas of controversy, and formulate questions for further research.