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Background and Aims: The course of adults with ZZ alpha‐1‐antitrypsin deficiency (AATD) liver disease is unpredictable. The utility of markers, including liver biopsy, is undefined. Methods: A prospective cohort, including protocol liver biopsies, was enrolled to address these questions. Results: We enrolled 96 homozygous ZZ AATD adults prospectively at three US sites with standardized clinical evaluations, and protocol liver biopsies. Fibrosis was scored using Ishak (stages 0–6). Also, 51% of the 96 subjects had Ishak score >1 fibrosis (49% Ishak 0–1, 36% Ishak 2–3 and 15% ≥4). Elevated aspartate aminotransferase (AST) more than alanine aminotransferase (ALT), high body mass index (BMI), obesity, AST platelet ratio index and elevated serum Z alpha 1 antitrypsin (AAT) polymer levels were associated with increased fibrosis. Steatosis did not correlate to fibrosis. Increased fibrosis was associated with increased mutant Z polymer globular inclusions (p =.002) and increased diffuse cytoplasmic Z polymer on biopsy (p =.0029) in a direct relationship. Increased globule Z polymer was associated with increased serum AST (p =.007) and increased periportal inflammation on histopathology (p =.004), but there was no relationship of Z polymer hepatocellular accumulation with ALT, gamma glutamine transferase, inflammation in other parts of the lobule, necrosis or steatosis. Serum Z polymer levels were directly correlated to hepatic Z protein polymer content. Lung function, smoking and alcohol consumption patterns were not associated with fibrosis. Conclusion: In AATD high BMI, obesity and elevated AST are associated with increased fibrosis. Liver biopsy features are correlated to some serum tests. Serum Z AAT polymer levels could be a future biomarker to detect fibrosis early and is directly correlated to liver Z content. [ABSTRACT FROM AUTHOR]

Cover Image: The cover image is based on the Article Fibrosis, biomarkers and liver biopsy in AAT deficiency and relation to liver Z protein polymer accumulation by Anandini Suri et al., https://doi.org/10.1111/liv.16094.By Anandini Suri; Zidong Zhang; Brent Neuschwander‐Tetri; David A. Lomas; Nina Heyer‐Chauhan; Keith Burling; Rohit Loomba; David A. Brenner; Rosemary Nagy; Andrew Wilson; Danielle Carpenter; Keith Blomenkamp and Jeffrey TeckmanReported by Author; Author; Author; Author; Author; Author; Author; Author; Author; Author; Author; Author; Author [Extracted from the article]

The formation of ordered Z (Glu342Lys) α1‐antitrypsin polymers in hepatocytes is central to liver disease in α1‐antitrypsin deficiency. In vitro experiments have identified an intermediate conformational state (M*) that precedes polymer formation, but this has yet to be identified in vivo. Moreover, the mechanism of polymer formation and their fate in cells have been incompletely characterised. We have used cell models of disease in conjunction with conformation‐selective monoclonal antibodies and a small molecule inhibitor of polymerisation to define the dynamics of polymer formation, accumulation and secretion. Pulse‐chase experiments demonstrate that Z α1‐antitrypsin accumulates as short‐chain polymers that partition with soluble cellular components and are partially secreted by cells. These precede the formation of larger, insoluble polymers with a longer half‐life (10.9 ± 1.7 h and 20.9 ± 7.4 h for soluble and insoluble polymers, respectively). The M* intermediate (or a by‐product thereof) was identified in the cells by a conformation‐specific monoclonal antibody. This was completely abrogated by treatment with the small molecule, which also blocked the formation of intracellular polymers. These data allow us to conclude that the M* conformation is central to polymerisation of Z α1‐antitrypsin in vivo; preventing its accumulation represents a tractable approach for pharmacological treatment of this condition; polymers are partially secreted; and polymers exist as two distinct populations in cells whose different dynamics have likely consequences for the aetiology of the disease. [ABSTRACT FROM AUTHOR]

The article discusses the serpinopathies have a diverse set of conformational diseases that involve the aberrant self-association of proteins to ordered aggregates. Topics include genetic variants such as the severe Z allele of 1-antitrypsin promote proteasomal degradation and the formation of ordered linear polymers; and the structure of the pathological polymers accumulate in patients has not been demonstrated.