Alpha-1-antitrypsin deficiency and liver disease

SPARTA clinical trial design: exploring the efficacy and safety of two dose regimens of alpha1-proteinase inhibitor augmentation therapy in alpha1-antitrypsin deficiency

BACKGROUND

Alpha1-antitrypsin deficiency (AATD) is an underdiagnosed genetic disorder that results in early-onset emphysema due to low serum levels of alpha1-proteinase inhibitor (alpha1-PI), leading to increased activity of tissue-damaging neutrophil elastase. Clinical outcomes of AATD may be improved by administering alpha1-PI augmentation therapy. Here, we describe the design of the ongoing Study of ProlAstin-c Randomized Therapy with Alpha-1 augmentation (SPARTA), a phase 3 trial designed to evaluate progression of lung tissue loss in patients with severe AATD receiving human alpha1-PI (Prolastin(®)-C) versus placebo, using whole-lung computed tomography (CT) densitometry.

STUDY DESIGN

SPARTA is a randomized, placebo-controlled trial assessing the efficacy and safety of two separate doses of Prolastin-C (60 and 120 mg/kg) administered weekly over 3 years in patients aged 18-70 years with a diagnosis of AATD and clinical evidence of pulmonary emphysema. The primary measure of efficacy (change from baseline whole-lung 15th percentile lung density [PD15]) will be determined by CT lung densitometry measured at total lung capacity. Secondary efficacy variables will be the evaluation of severe chronic obstructive pulmonary disease exacerbations, as defined by American Thoracic Society/European Respiratory Society criteria, and PD15 of the basal lung region using CT densitometry. Adverse events will be collected and documented.

CONCLUSIONS

The SPARTA trial is designed to evaluate the long-term (3-year) efficacy of 2 separate doses of Prolastin-C for the treatment of emphysema in patients with AATD. Protocol number: GTi1201.

CLINICAL TRIALS IDENTIFIER

NCT01983241.

Tissue-specific actions of FXR in metabolism and cancer

The nuclear Farnesoid X Receptor (FXR) is a transcription factor critically involved in metabolic homeostasis in the gut-liver axis. FXR activity is mediated by hormonal and dietary signals and driven by bile acids (BAs), which are the natural FXR ligands. Given the great physiological importance in BA homeostasis, as well as in the regulation of glucose and lipid metabolism, FXR plays a pivotal role in the pathogenesis of a wide range of disease of the liver, biliary tract and intestine, including hepatic and colorectal cancer. In the last years several studies have shown the relative FXR tissue-specific importance, highlighting synergism and additive effects in the liver and intestine. Gain- and loss-of-FXR-function mouse models have been generated in order to identify the biological processes and the molecular FXR targets. Taking advantage of the knowledge on the structure-activity relationship of BAs for FXR, semi-synthetic and synthetic molecules have been generated to obtain more selective and powerful FXR activators than BAs. This article is part of a Special Issue entitled: Linking transcription to physiology in lipodomics.

Deciphering the nuclear bile acid receptor FXR paradigm

Originally called retinoid X receptor interacting protein 14 (RIP14), the farnesoid X receptor (FXR) was renamed after the ability of its rat form to bind supra-physiological concentrations of farnesol. In 1999 FXR was de-orphanized since primary bile acids were identified as natural ligands. Strongly expressed in the liver and intestine, FXR has been shown to be the master transcriptional regulator of several entero-hepatic metabolic pathways with relevance to the pathophysiology of conditions such as cholestasis, fatty liver disease, cholesterol gallstone disease, intestinal inflammation and tumors. Furthermore, given the importance of FXR in the gut-liver axis feedbacks regulating lipid and glucose homeostasis, FXR modulation appears to have great input in diseases such as metabolic syndrome and diabetes. Exciting results from several cellular and animal models have provided the impetus to develop synthetic FXR ligands as novel pharmacological agents. Fourteen years from its discovery, FXR has gone from bench to bedside; a novel nuclear receptor ligand is going into clinical use.

Tempting liver fibrosis? Long-term psoriatic methotrexate therapy and heterozygous alpha1-antitrypsin deficiency

BACKGROUND

Dermatologists, or pathologists, occasionally need to decide whether or not to continue methotrexate therapy in a patient with an identifiable risk factor for liver fibrosis, in this instance heterozygous alpha(1)-antitrypsin deficiency.

CASE PRESENTATION

We relate our experience with an elderly male patient, diagnosed as having alpha(1)-antitrypsin deficiency on a liver biopsy, genotypically confirmed as PiMZ. He had been receiving methotrexate for psoriasis for 17 years with a cumulative dose of 7,200 mg. He was monitored by biochemical profiling and interval (10) liver biopsies. Non-specific changes were seen on liver histology although grade 1 liver fibrosis was seen in his last 2 biopsies.

CONCLUSION

We suggest that methotrexate therapy is relatively safe in patients with heterozygous alpha(1)-antitrypsin deficiency, with no other risk factor. We however advise that the risk of fibrosis should be monitored and that the patient receives appropriate counselling.

Purification and partial characterization of feline α1-proteinase inhibitor (fα1-PI) and the development and validation of a radioimmunoassay for the measurement of fα1-PI in serum

Alpha(1)-proteinase inhibitor (alpha(1)-PI) of the domestic cat (Felis catus) was purified from serum and a radioimmunoassay (RIA) for the measurement of feline alpha(1)-PI concentration in serum was developed and validated. Feline alpha(1)-PI (falpha(1)-PI) was isolated using ammonium sulfate precipitation, anion-exchange, size-exclusion, ceramic hydroxyapatite, and hydrophobic interaction chromatography. The molecular weight of falpha(1)-PI was estimated at 57,000 and the relative molecular mass (M(r)) was determined to be approximately 54.5 kDa. Isoelectric focusing revealed four bands with isoelectric points (pI) between 4.3 and 4.5. The N-terminal amino acid sequence of the first 19 residues was Glu-Gly-Leu-Gln-Gly-Ala-Ala-Val-Gln-Glu-Thr-Val-Ala-Ser-Gln-His-Asp-Gln-Glu. Antiserum against feline alpha(1)-PI was raised in rabbits. Tracer was produced by iodination ((125)I) of feline alpha(1)-PI using the chloramine T method. A radioimmunoassay was established and validated by determination of sensitivity, dilutional parallelism, spiking recovery, intra-assay variability, and inter-assay variability. A control range for serum feline alpha(1)-PI concentration was established from 50 healthy cats using the central 95th percentile. The sensitivity of the assay was 0.042 mg/ml. Observed to expected ratios for serial dilutions ranged from 105% to 141.18% for four different serum samples at dilutions of 1 in 35,000, 1 in 70,000, 1 in 140,000 and 1 in 280,000. Observed to expected ratios for spiking recovery ranged from 88.14% to 152.17% for four different serum samples and five different spiking concentrations. Coefficients of variation for four different serum samples were 4.57%, 6.45%, 8.52%, and 4.27% for intra-assay variability and 6.88%, 9.57%, 7.44%, and 9.94% for inter-assay variability. The reference range was established as 0.25-0.6 mg/ml. In summary, feline alpha(1)-PI was successfully purified from serum using a rapid and efficient method. The radioimmunoassay described here is sensitive, linear, accurate, precise, and reproducible and will facilitate further studies of the physiological or potential pathological role of alpha(1)-PI in cats.

Serum alpha-1-antitrypsin concentration during normal and diabetic pregnancy

OBJECTIVES

The aim of this study was a comparison of serum alpha-1-antitrypsin (AAT) concentration in the course of normal and diabetic pregnancy.

METHODS

Serum AAT concentration was determined on NOR-Partigen plates (Behring Diagnostics GmbH, Marburg). The studied material included healthy women without pregnancy (n=14), healthy pregnant women in the first trimester (n=12), second trimester (n=15), third trimester (n=15), and 16 pregnant women with type-1 diabetes mellitus studied prospectively in successive stages of pregnancy.

RESULTS

In the first trimester of normal pregnancy, a significant increase of serum AAT concentration was observed in comparison with healthy women without pregnancy (P<0.01). In all stages of pregnancy with type-1 diabetes mellitus, a higher increase of AAT concentration was found as compared with healthy pregnant women (P<0.0001), especially in third trimester. There was no correlation shown between concentration of AAT and fructosamine in the serum of healthy and diabetic pregnant women (P>0.05).

CONCLUSIONS

During normal and diabetic pregnancy, an increase of serum AAT concentration occurred with the regression lines exhibiting a different slopes. The highest AAT concentration was observed in third trimester of diabetic pregnancy. Increase in concentration of AAT in the serum of pregnant women with diabetes does not depend on the value of glycaemic control.

Diagnosis and monitoring of hepatic injury. II. Recommendations for use of laboratory tests in screening, diagnosis, and monitoring

Purpose: To review information on the use of laboratory tests in screening, diagnosis, and monitoring of acute and chronic hepatic injury.

Data Sources and Study Selection: A MEDLINE search was performed for key words related to hepatic diseases, including acute hepatitis, chronic hepatitis, alcoholic hepatitis, cirrhosis, hepatocellular carcinoma, and etiologic causes. Abstracts were reviewed, and articles discussing use of laboratory tests selected for review. Additional articles were selected from the references.

Guideline Preparation and Review: Drafts of the guidelines were posted on the Internet, presented at the AACC Annual Meeting in 1999, and reviewed by experts. Areas requiring further amplification or literature review were identified for further analysis. Specific recommendations were made based on analysis of published data and evaluated for strength of evidence and clinical impact.

Recommendations: Although many specific recommendations are made in the guidelines, only some summary recommendations are listed here. In acute hepatic injury, prothrombin time and, to a lesser extent, total bilirubin are the best indicators of severity of disease. Although ALT is useful for detecting acute and chronic hepatic injury, it is not related to severity of acute hepatic injury and only weakly related to severity of chronic hepatic injury. Specific tests of viral markers should be the initial differential tests in both acute and chronic hepatic injury; when positive, they are also useful for monitoring recovery from hepatitis B and C.

Pathologic features of chronic hepatitis. A review and update

The general histopathologic changes of chronic hepatitis and those related to the various causes are reviewed. Consideration also is given to underlying or associated diseases and to mixed infections in chronic viral hepatitis. Changes occurring in exacerbations or relapses are described. Selected histopathologic changes are illustrated. The nomenclature is reviewed briefly, with emphasis on separation of activity from stage of disease.

Enhanced phenotypic expression of alpha-1-antitrypsin deficiency in an MZ heterozygote with chronic hepatitis C

A middle-aged white man of Scotch-Irish ancestry, being treated for chronic hepatitis C, was found to be heterozygous for alpha1-antitrypsin deficiency (PiMZ phenotype) after diagnostic PAS-positive, diastase-resistant globules were detected in a liver biopsy. The globules had not been present in a biopsy obtained 4 yr previously. He was also found to be heterozygous for the cys282tyr mutation of the HFE gene, which is the chief cause of HLA-linked hereditary hemochromatosis (HHC). His liver disease progressed over 4 yr from mild hepatitis to moderate hepatitis with cirrhosis despite therapy with interferon-alpha, and phlebotomy plus interferon. These conditions appeared to have synergistic effects, with the chronic viral hepatitis unmasking the alpha1AT deficiency, and the alpha1AT deficiency (and possibly the heterozygosity for HHC), exacerbating the course of the hepatitis C.