α1-Antitrypsin deficiency: best clinical practice

Serum a-1 antitrypsin as a novel biomarker in chronic heart failure

AIMS

Chronic heart failure (CHF) remains a major health issue worldwide. In the present study, we aimed to identify novel circulating biomarkers for CHF using serum proteomics technology and to validate the biomarker in three independent cohorts.

METHODS AND RESULTS

The isobaric tags for relative and absolute quantitation technology was utilized to identify the potential biomarkers of CHF. The validation was conducted in three independent cohort. Cohort A included 223 patients with ischaemic heart disease (IHD) and 321 patients with ischaemic heart failure (IHF) from the CORFCHD-PCI study. Cohort B recruited 817 patients with IHD and 1139 patients with IHF from the PRACTICE study. Cohort C enrolled 559 non-ischaemic heart disease patients with CHF (n = 316) or without CHF (n = 243). We found the expression of a-1 antitrypsin (AAT) was elevated significantly in patients with CHF compared with that in the patients with stable IHD using statistical and bioinformatics analyses. In a validation study, there was a significant difference between patients with stable IHD and patients with IHF in AAT concentration either in cohort A (1.35 ± 0.40 vs. 1.64 ± 0.56, P < 0.001) or in cohort B (1.37 ± 0.42 vs. 1.70 ± 0.48, P < 0.001). The area under the receiver operating characteristic curve was 0.70 [95% confidence interval (CI): 0.66 to 0.74, P < 0.001] in cohort A and 0.74 (95% CI: 0.72 to 0.76, P < 0.001) in cohort B. Furthermore, AAT was negative correlated with left ventricular ejection fraction (r = -0.261, P < 0.001). After adjusting for confounders using a multivariate logistic regression analysis, AAT remained an independent association with CHF in both cohort A (OR = 3.14, 95% CI: 1.667 to 5.90, P < 0.001) and cohort B (OR = 4.10, 95% CI: 2.97 to 5.65, P < 0.001). This association was also validated in cohort C (OR = 1.86, 95% CI: 1.02 to 3.38, P = 0.043).

CONCLUSIONS

The present study suggests that serum AAT is a reliable biomarker for CHF in a Chinese population.

The Mechanism of Mitochondrial Injury in Alpha-1 Antitrypsin Deficiency Mediated Liver Disease

Alpha-1 antitrypsin deficiency (AATD) is caused by a single mutation in the SERPINA1 gene, which culminates in the accumulation of misfolded alpha-1 antitrypsin (ZAAT) within the endoplasmic reticulum (ER) of hepatocytes. AATD is associated with liver disease resulting from hepatocyte injury due to ZAAT-mediated toxic gain-of-function and ER stress. There is evidence of mitochondrial damage in AATD-mediated liver disease; however, the mechanism by which hepatocyte retention of aggregated ZAAT leads to mitochondrial injury is unknown. Previous studies have shown that ER stress is associated with both high concentrations of fatty acids and mitochondrial dysfunction in hepatocytes. Using a human AAT transgenic mouse model and hepatocyte cell lines, we show abnormal mitochondrial morphology and function, and dysregulated lipid metabolism, which are associated with hepatic expression and accumulation of ZAAT. We also describe a novel mechanism of ZAAT-mediated mitochondrial dysfunction. We provide evidence that misfolded ZAAT translocates to the mitochondria for degradation. Furthermore, inhibition of ZAAT expression restores the mitochondrial function in ZAAT-expressing hepatocytes. Altogether, our results show that ZAAT aggregation in hepatocytes leads to mitochondrial dysfunction. Our findings suggest a plausible model for AATD liver injury and the possibility of mechanism-based therapeutic interventions for AATD liver disease.

A Case of Alpha-1 Antitrypsin Deficiency and Organizing Pneumonia

Alpha-1 antitrypsin deficiency (AATD) is an autosomal dominant genetic disorder that presents with pulmonary complications and is most commonly manifested by panacinar emphysema and chronic obstructive pulmonary disease. A 49-year-old Caucasian female with a history of AATD and chronic tobacco use was referred to both infectious disease and thoracic surgery clinics with worsening cough and chronic intermittent hemoptysis for the evaluation of possible superimposed infection or malignancy. She had previously been treated with multiple antibiotics and Prolastin-CÒ (alpha-1-proteinase inhibitor). Initial CT of the chest showed known chronic bronchiectasis, severe lower lung emphysema, and right-sided lower lobe pulmonary masses. CT-guided biopsy of one mass showed nonspecific inflammation, negative cultures, and negative cytology. Subsequent follow-up with chest CT scans showed a decreasing size of right-sided pulmonary masses and new left-sided nodule formation, which later stabilized in growth. Based on symptoms and radiological and pathological findings, a diagnosis of organizing pneumonia was made. We present an unusual case of bilateral pulmonary masses mimicking infection and malignancy later found to be most consistent with an organizing pneumonia in a patient with underlying AATD.

Alpha-1 antitrypsin deficient individuals have circulating extracellular vesicles with profibrogenic cargo

Background

Alpha-1 antitrypsin deficiency (AATD)-mediated liver disease is a toxic “gain-of-function” inflammation in the liver associated with intracellular retention of mutant alpha-1 antitrypsin. The clinical presentation of the disease includes fibrosis, cirrhosis and liver failure. However, the pathogenic mechanism of AATD-mediated liver disease is not well understood. Here, we investigated the role of plasma extracellular vesicles (EVs) in progression of AATD-mediated liver disease.

Methods

EVs were isolated from plasma of AATD individuals with liver disease and healthy controls. Their cytokines and miRNA content were examined by multiplex assay and small RNA sequencing. The bioactivity of EVs was assessed by qPCR, western blot analysis and immunofluorescent experiments using human hepatic stellate cells (HSCs) treated with EVs isolated from control or AATD plasma samples.

Results

We have found that AATD individuals have a distinct population of EVs with pathological cytokine and miRNA contents. When HSCs were cultured with AATD plasma derived-EVs, the expression of genes related to the development of fibrosis were significantly amplified compared to those treated with healthy control plasma EVs.

Conclusion

AATD individuals have a distinct population of EVs with abnormal cytokine and miRNA contents and the capacity to activate HSCs and mediate fibrosis. Better understanding of the components which cause liver inflammation and fibrogenesis, leading to further liver injury, has the potential to lead to the development of new treatments or preventive strategies to prevent AATD-mediated liver disease.

Neonatal cholestasis: recent insights

Background

Neonatal physiological jaundice is a common benign condition that rarely extends behind the second week of life; however, it may interfere with the diagnosis of a pathological condition termed neonatal cholestasis (NC). The latter is a critical, uncommon problem characterized by conjugated hyperbilirubinaemia. This review aims to highlight the differences between physiological and pathological jaundice, identify different causes of NC, and provide a recent approach to diagnosis and management of this serious condition.

Main text

NC affects 1/2500 live births, resulting in life-threatening complications due to associated hepatobiliary or metabolic abnormalities. NC is rarely benign and indicates the presence of severe underlying disease. If jaundice extends more than 14 days in full-term infants or 21 days in preterm infants, the serum bilirubin level fractionated into conjugated (direct) and unconjugated (indirect) bilirubin should be measured. A stepwise diagnostic approach starts with obtaining a complete history, and a physical examination which are valuable for the rapid diagnosis of the underlying disease. The most frequently diagnosed causes of NC are biliary atresia (BA) and idiopathic neonatal hepatitis (INH). The early diagnosis of NC ensures more accurate management and better prognosis. Despite the unavailability of any specific treatments for some causes of NC, the patient can benefit from nutritional management and early medical intervention. Future research should attempt to shed light on methods of screening for NC, especially for causes that can be effectively treated either through proper nutritional support, appropriate chemotherapeutic management, or timely surgical intervention.

Conclusion

Further attention should be paid for diagnosis and treatment of NC as it may be misdiagnosed as physiological jaundice; this may delay the proper management of the underlying diseases and aggravates its complications.

Alpha1-Antitrypsin Deficiency: Transition of Care for the Child With AAT Deficiency into Adulthood

IMPORTANCE

Alpha1-antitrypsin (AAT) deficiency is a common, but an underdiagnosed genetic condition, affecting 1 in 1500 individuals. It can present insidiously with liver disease in children. Although clinical practice guidelines exist for the management of AAT deficiency, especially with regards to pulmonary involvement, there are no published recommendations that specifically relate to the management of the liver disease and monitoring for lung disease associated with this condition, particularly in children.

OBJECTIVE

To review the literature on the management of AAT deficiency-associated liver disease in adults and children.

EVIDENCE REVIEW

A systematic search for articles indexed in PubMed and published was undertaken. Some earlier selected landmark references were included in the review. Search terms included: "alpha1-antitrypsin deficiency"; "liver disease"; "end-stage liver disease"; "liver transplantation" and "preventative management". Recommendations for the management of children with suspected or confirmed AAT deficiency were made according to the Strength of Recommendation Taxonomy scale.

FINDINGS

Liver complications arising from AAT deficiency result from the accumulation of mutated AAT protein within hepatocytes. Liver disease occurs in 10% of children, manifested by cholestasis, pruritus, poor feeding, hepatomegaly, and splenomegaly, but the presentation is highly variable. A diagnostic test for AAT deficiency is recommended for these children. Baseline liver function tests should be obtained to assess for liver involvement; however, the only curative treatment for AAT deficiency-associated liver disease is organ transplantation. Conclusion and Relevance: There should be a greater vigilance for AAT deficiency testing among pediatricians. Diagnosis should prompt assessment of liver involvement. Children with AATdeficiency- associated liver disease should be referred to a liver specialist and monitored throughout their lifetimes for the symptoms of AAT-deficiency-related pulmonary involvement.

IgE-tailpiece associates with α-1-antitrypsin (A1AT) to protect IgE from proteolysis without compromising its ability to interact with FcεRI

Several splice variants of IgE exist in human plasma, including a variant called IgE-tailpiece (IgE-tp) that differs from classical IgE by the replacement of two carboxy-terminal amino acids with eight novel residues that include an ultimate cysteine. To date, the role of the secreted IgE-tp isoform in human immunity is unknown. We show that levels of IgE-tp are raised in helminth-infected donors, and that both the classical form of IgE (IgE-c) and IgE-tp interact with polymers of the serine protease inhibitor alpha-1-antitrypsin (A1AT). The association of IgE-tp with A1AT polymers in plasma protects the antibody from serine protease-mediated degradation, without affecting the functional interaction of IgE-tp with important receptors, including FcεR1. That polymers of A1AT protect IgE from degradation by helminth proteases may explain why these common and normally non-disease causing polymorphic variants of A1AT have been retained by natural selection. The observation that IgE can be complexed with polymeric forms of A1AT may therefore have important consequences for our understanding of the pathophysiology of pulmonary diseases that arise either as a consequence of A1AT-deficiency or through IgE-mediated type 1 hypersensitivity responses.

Indications for active case searches and intravenous alpha-1 antitrypsin treatment for patients with alpha-1 antitrypsin deficiency chronic pulmonary obstructive disease: an update

The effect of hereditary alpha-1 antitrypsin (AAT) deficiency can manifest clinically in the form of chronic obstructive pulmonary disease (COPD). AAT deficiency (AATD) is defined as a serum concentration lower than 35% of the expected mean value or 50 mg/dl (determined by nephelometry). It is associated in over 95% of cases with Pi*ZZ genotypes, and much less frequently with other genotypes resulting from combinations of Z, S, rare and null alleles. A systematic qualitative review was made of 107 articles, focusing mainly on an active search for AATD in COPD patients and intravenous (iv) treatment with AAT. On the basis of this review, the consultant committee of the Spanish Registry of Patients with AATD recommends that all COPD patients be screened for AATD with the determination of AAT serum concentrations, and when these are low, the evaluation must be completed with phenotyping and, on occasions, genotyping. Patients with severe AATD COPD should receive the pharmacological and non-pharmacological treatment recommended in the COPD guidelines. There is enough evidence from large observational studies and randomized placebo-controlled clinical trials to show that the administration of iv AAT reduces mortality and slows the progression of emphysema, hence its indication in selected cases that meet the inclusion criteria stipulated in international guidelines. The administration of periodic infusions of AAT is the only specific treatment for delaying the progression of emphysema associated with AATD.

Therapy with plasma purified alpha1-antitrypsin (Prolastin®) induces time-dependent changes in plasma levels of MMP-9 and MPO

The common Z mutation (Glu342Lys) of α1-antitrypsin (A1AT) results in the polymerization and intracellular retention of A1AT protein. The concomitant deficiency of functional A1AT predisposes PiZZ subjects to early onset emphysema. Clinical studies have implied that, among the biomarkers associated with emphysema, matrix metalloproteinase 9 (MMP-9) is of particular importance. Increased plasma MMP-9 levels are proposed to predict the decline of lung function as well as greater COPD exacerbations in A1AT deficiency-associated emphysema. The aim of the present study was to investigate the effect of A1AT therapy (Prolastin) on plasma MMP-9 and myeloperoxidase (MPO) levels. In total 34 PiZZ emphysema patients were recruited: 12 patients without and 22 with weekly intravenous (60 mg/kg body weight) A1AT therapy. The quantitative analysis of A1AT, MMP-9 and MPO was performed in serum and in supernatants of blood neutrophils isolated from patients before and after therapy. Patients with Prolastin therapy showed significantly lower serum MMP-9 and MPO levels than those without therapy. However, parallel analysis revealed that a rapid infusion of Prolastin is accompanied by a transient elevation of plasma MMP-9 and MPO levels. Experiments with freshly isolated blood neutrophils confirmed that therapy with Prolastin causes transient MMP-9 and MPO release. Prolastin induced the rapid release of MMP-9 and MPO when added directly to neutrophil cultures and this reaction was associated with the presence of IgA in A1AT preparation. Our data support the conclusion that changes in plasma levels of MMP-9 and MPO mirror the effect of Prolastin on blood neutrophils.

Diagnosis of alpha-1 antitrypsin deficiency: modalities, indications and diagnosis strategy

Alpha-1 antitrypsin (α1-AT) deficiency is an autosomal recessive genetic disorder, which predisposes affected patients to development of pulmonary emphysema or liver cirrhosis. Despite the guidelines from the American Thoracic Society and the European Respiratory Society about α1-AT deficiency screening, it remains significantly under recognized. So, it seems necessary to propose an efficient and suitable biological approach to improve diagnosis and management of α1-AT deficiency. α1-AT is a 52 kDa glycoprotein predominantly produced in the liver and its physiological serum concentration for adults ranges from 0.9 to 2.0g/L (17-39 μmol/L). It is encoded by the SERPINA1 gene, which is highly pleomorphic, and to date, more than 100 alleles have been identified. α1-AT testing would initially involve quantification of serum α1-AT concentration with possible complementary measurement of the elastase inhibitory capacity of serum. If the serum α1-AT concentration is reduced below the reference value, two strategies for laboratory testing can be used: (i) serum α1-AT phenotyping by isoelectric focusing which allows identification of the most common variant designated as the PI M variant but also of various deficient variants besides the predominant PI S and PI Z ones; (ii) genotyping by allele-specific PCR methods which allows only identification of the deficient PI S and PI Z alleles. Identification of the null alleles or of other rare deficient alleles can be performed by direct sequencing of the whole SERPINA1 gene as a reflex test.

The effects of cigarette smoking on prostate-specific antigen in two different age groups

BACKGROUND

We investigate the effects of cigarette smoking on prostate-specific antigen (PSA) using 2 different age groups.

METHODS

The study was carried out between January 2007 and October 2011 with men; the 2 sets of age groups were: 25 to 35 years and 50 to 70 years old. The participants were divided into 4 groups. Of the 25 to 35 age range, smokers were Group 1, and non-smokers were Group 2; of the 50 to 70 age range, smokers were Group 3 and non-smokers Group 4. In addition, for the 50 to 70 age group, the International Prostate Symptom Score was completed, digital rectal examination was performed, and transabdominal prostate volume was measured. We wanted to see whether prostate-specific antigen (PSA) levels showed a difference between the 2 age groups.

RESULTS

There were 114 patients in Group 1, 82 in Group 2, 90 in Group 3, and 102 in Group 4. The mean PSA level was 0.7 ± 0.28 ng/mL for Group 1, and 0.6 ± 0.27 ng/mL for Group 2 (p = 0.27), and there was no statistically significant difference between the 2 groups. The mean PSA was 2.5 ± 1.8 ng/mL for Group 3, and 2.1 ± 2.0 ng/mL (p = 0.59) for Group 4, and there was no statistically significant difference between the these 2 age groups.

INTERPRETATION

Cigarette smoking effects various hormone levels. Different from previous studies, the PSA level was higher in smokers compared to nonsmokers, although it was not statistically significant. Our study is limited by the small numbers in our study groups and the lack of PSA velocity data.

A rare variant of α 1 antitrypsin mutations detected in Vietnamese children with liver disease

BACKGROUND

Alpha 1 antitrypsin (A1AT) is the major plasma serine protease inhibitor that is produced in liver cells. A1AT deficiency is recognized globally as a common genetic cause of liver disease in children, which results from mutations in the SERine Protease INhibitor A1 (SERPINA1) gene. The importance of A1AT deficiency in Viet Nam is unclear. The aim of this study was to determine the A1AT variants present in paediatric patients with liver diseases in order to clarify whether A1AT deficiency is present in Viet Nam.

METHODS

A1AT studies were carried out in 130 children with liver disease of indeterminate aetiology. A1AT levels were determined by immunoturbidimetry. Phenotype analysis of A1AT was performed by isoelectric focusing (IEF) in all patients. Genotype analyses to determine A1AT mutations were performed by direct sequencing.

RESULTS

We identified a rare variant of A1AT named Zbristol. The Zbristol appeared to be deficient in the plasma to about the same degree as the PI S protein resulting in low concentration of A1AT in one of these two Vietnamese patients. No other deficient A1AT allele was detected, although 11 patients (8.5%) showed a reduced serum concentration of A1AT.

CONCLUSIONS

These are the first two cases of a rare A1AT deficiency allele to be found in Viet Nam clearly inferring that A1AT deficiency is not just a disease of Caucasians. As such, the laboratory diagnosis of A1AT deficiency including A1AT concentration determination and phenotype and genotype testing should form part of the routine differential diagnosis of paediatric liver disease of indeterminate aetiology in Vietnamese patients.

Development and analysis of alpha 1-antitrypsin neoglycoproteins: the impact of additional N-glycosylation sites on serum half-life

Therapeutic efficacy of glycoproteins is affected by many factors, including molecular size and net charge; both are influenced by the presence and composition of glycan structures. Human alpha 1-antitrypsin (A1AT) was cloned and expressed in human embryonic kidney cells (HEK293) that are capable of mammalian glycosylation. Utilizing PCR-based site-directed mutagenesis, new A1AT variants were created with single, double, or triple additional N-glycosylation sites to the three naturally occurring N-glycosylation sites. Because of the supplementary N-glycans, the A1AT variants exhibited an increased molecular weight. Retention of inhibitory activity was shown via trypsin inhibitory assay. The A1AT variants were treated with PNGase F, and the resulting N-glycans were analyzed by MALDI-TOF mass spectrometry. The N-glycan profile of the recombinant A1AT variants was mostly composed of monofucosylated bi-, tri-, and tetraantennary complex-type N-glycans, with a tendency toward higher antennary structures compared to the wild-type. The relevance of N-glycosylation in A1AT for the circulatory serum half-life was demonstrated in CD1 mice. The A1AT neoglycoprotein with an additional N-glycosylation site at position N123 exhibited a 62% increase in serum half-life. Additionally, using a two-compartment model, the A1AT variants exhibited increased α-phase values, especially N123 (223%) and N201 (255%). The results suggest the recombinant A1AT neoglycoprotein as a serious alternative to A1AT derived from human plasma.

Efficient inhibition of human leukocytic elastase by means of α1-antitrypsin/peptide complexes

α1 -Antitrypsin (AT), a serine protease inhibitor that specifically targets hydrolytic enzymes, plays a significant role in the termination of tissue inflammation and can therefore represent a key factor in chronic incidences as chronic obstructive pulmonary disease (COPD) or chronic hepatitis. A local and low-dose therapy for the treatment of acquired chronic inflammatory processes which are characterized by insufficient AT amounts but also of genetically conditioned AT deficiencies is supposed to be more effective and less cost-intensive compared to current therapies. In this study, a noncovalent complex formation between the cell-penetrating peptide carrier hCT(18-32)-k7 and AT was performed. The complex was applied to HEK293T/17 cells, as proof-of-principle, and polymorphonuclear leukocytes (PMN), which are responsible for tissue destruction and the perpetuation of inflammation in chronic processes. Both cell species show a successful uptake and subsequently both, an intracellular dot-shaped and homogeneous distribution of the complex demonstrating phagolysosomal as well as cytoplasmic availability. Furthermore, a decreased human leukocytic elastase (HLE) activity was observed after the direct complex administration to PMN. Since the application did not cause an enhanced vitality loss, the complex could facilitate an improvement in direct, local and low-dose treatment of chronically proceeding processes in order to attenuate protease-mediated tissue destruction.

Performance of enhanced liver fibrosis plasma markers in asymptomatic individuals with ZZ α1-antitrypsin deficiency

OBJECTIVES

Alpha1-antitrypsin deficiency (AATD) is a common genetic cause of chronic liver disease. According to retrospective studies, up to 25% of those with homozygous ZZ (Glu 342 to Lys) AATD suffer from liver cirrhosis and/or liver cancer in late adulthood. We hypothesized that the plasma markers for liver fibrosis, necrosis, and apoptosis may identify AATD individuals at higher risk for liver diseases.

METHODS

The study cohort included 52 clinically healthy ZZ AATD individuals of 34 years of age, identified in the Swedish neonatal screening of 1972-1974, and 81 age-matched controls with normal MM AAT variant. We analyzed plasma levels of the enhanced liver fibrosis (ELF) panel, including plasma tissue inhibitor of metalloprotease-1, amino-terminal propeptide of type III collagen and hyaluronic acid (HA), and the M30 and M65 antigens, markers for apoptosis/necrosis.

RESULTS

Higher levels of tissue inhibitor of metalloprotease-1 (52%, P<0.001), amino-terminal propeptide of type III collagen (12%, P<0.05), HA (17% not significant), and M65 (13.4%, P=0.043) were found in ZZ than in MM patients. In the ZZ group, plasma levels of AAT correlated with M65 (P<0.01) and with HA (P<0.05). On the basis of the ELF panel, M30 and M65, a logistic regression model enabled us to correctly classify 81.2% of the originally grouped ZZ and MM cases with a sensitivity of 73.1% and a specificity of 86.4%.

CONCLUSION

The ELF markers are associated with ZZ AATD at early adulthood, and can be considered as a useful tool to identify ZZ cases at an increased risk of developing liver diseases later in life.

A comprehensive evaluation of potential lung function associated genes in the SpiroMeta general population sample

RATIONALE

Lung function measures are heritable traits that predict population morbidity and mortality and are essential for the diagnosis of chronic obstructive pulmonary disease (COPD). Variations in many genes have been reported to affect these traits, but attempts at replication have provided conflicting results. Recently, we undertook a meta-analysis of Genome Wide Association Study (GWAS) results for lung function measures in 20,288 individuals from the general population (the SpiroMeta consortium).

OBJECTIVES

To comprehensively analyse previously reported genetic associations with lung function measures, and to investigate whether single nucleotide polymorphisms (SNPs) in these genomic regions are associated with lung function in a large population sample.

METHODS

We analysed association for SNPs tagging 130 genes and 48 intergenic regions (+/-10 kb), after conducting a systematic review of the literature in the PubMed database for genetic association studies reporting lung function associations.

RESULTS

The analysis included 16,936 genotyped and imputed SNPs. No loci showed overall significant association for FEV(1) or FEV(1)/FVC traits using a carefully defined significance threshold of 1.3×10(-5). The most significant loci associated with FEV(1) include SNPs tagging MACROD2 (P = 6.81×10(-5)), CNTN5 (P = 4.37×10(-4)), and TRPV4 (P = 1.58×10(-3)). Among ever-smokers, SERPINA1 showed the most significant association with FEV(1) (P = 8.41×10(-5)), followed by PDE4D (P = 1.22×10(-4)). The strongest association with FEV(1)/FVC ratio was observed with ABCC1 (P = 4.38×10(-4)), and ESR1 (P = 5.42×10(-4)) among ever-smokers.

CONCLUSIONS

Polymorphisms spanning previously associated lung function genes did not show strong evidence for association with lung function measures in the SpiroMeta consortium population. Common SERPINA1 polymorphisms may affect FEV(1) among smokers in the general population.

Alpha1-antitrypsin deficiency: a clinical-genetic overview

Severe α1-antitrypsin deficiency (AATD) is an inherited disorder, leading to development of emphysema in smokers at a relatively young age with disability in their forties or fifties. The emphysema results from excessive elastin degradation by neutrophil elastase as a result of the severe deficiency of its major inhibitor α1-antitrypsin (AAT). The AAT expression is determined by the SERPINA1 gene which expresses codominant alleles. The three most common alleles are the normal M, the S with plasma levels of 60% of normal, and the severely deficient Z with levels of about 15% of normal. Homozygosity for the Z mutant allele is associated with retention of abnormal AAT in the liver, which may lead to neonatal hepatitis, liver disease in children, and liver disease in adults. Regular intravenous infusions of purified human AAT (AAT augmentation therapy) have been used to partially correct the biochemical defect and protect the lung against further injury. Two randomized controlled trials showed a trend of slower progression of emphysema by chest computerized tomography. Integrated analysis of these two studies indicated significantly slower progression of emphysema. AAT is quantified by immunologic measurement of AAT in serum, the phenotype characterized by isoelectric focusing, the common genotypes by targeted DNA analysis, and by sequencing the coding region of the gene when the AAT abnormality remains undefined. AATD is often unrecognized, and diagnosis delayed. Testing for AATD is recommended in patients with chronic irreversible airflow obstruction, especially in those with early onset of disease or positive family history. Testing is also recommended for immediate family members of those with AATD, asthmatics with persistent airflow obstruction, and infants and older subjects with unexplained liver disease. There are over 100 different AAT gene variants; most are rare and only some are associated with clinical disease.

The discovery of α1-antitrypsin and its role in health and disease

α1-Antitrypsin (AAT) is the archetype member of the serine protease inhibitor (SERPIN) supergene family. The AAT deficiency is most often associated with the Z mutation, which results in abnormal Z AAT folding in the endoplasmic reticulum of hepatocytes during biogenesis. This causes intra-cellular retention of the AAT protein rather than efficient secretion with consequent deficiency of circulating AAT. The reduced serum levels of AAT contribute to the development of chronic obstructive pulmonary disease (COPD) and the accumulation of abnormally folded AAT protein increases risk for liver diseases. In this review we show that with the discovery of AAT deficiency in the early 60s as a genetically determined predisposition to the development of early-onset emphysema, intensive investigations of enzymatic mechanisms that produce lung destruction in COPD were pursued. To date, the role of AAT in other than lung and liver diseases has not been extensively examined. Current findings provide new evidence that, in addition to protease inhibition, AAT expresses anti-inflammatory, immunomodulatory and antimicrobial properties, and highlight the importance of this protein in health and diseases. In this review co-occurrence of several diseases with AAT deficiency is discussed.

Lung deposition of inhaled alpha-1-proteinase inhibitor (alpha 1-PI) - problems and experience of alpha1-PI inhalation therapy in patients with hereditary alpha1-PI deficiency and cystic fibrosis

Alpha-1-proteinase inhibitor (α1-PI) is the most relevant protease inhibitor in the lung. Patients with hereditary deficiency of α1-PI suffer from an impaired hepatic synthesis of α1-PI in the liver and in consequence an insufficient concentration of the protease inhibitor in the lung followed by development of lung emphysema due to an impaired protease antiprotease balance and a local relative excess of neutrophil elastase (NE). In contrast, patients with cystic fibrosis (CF) are characterised by a normal synthesis of α1-PI and a severe pulmonary inflammation with a strong excess of NE in the lung followed by progressive loss of lung function. In principle, both patient groups may benefit from an augmentation of α1-PI. Intravenous augmentation, which is established in patients with α1-PI deficiency only, is very expensive, subject to controversial discussions and only about 2% of the administered protein reaches lung interstitium. Inhalation of α1-PI may serve as an alternative to administer high α1-PI doses into the lungs of both patient groups to restore the impaired protease antiprotease balance and to diminish the detrimental effects of NE. However, prerequisites of this therapy are the reproducible administration of sufficient doses of active α1-PI into the lung without adverse effects. In our review we describe the results of studies investigating the inhalation of α1-PI in patients with α1-PI deficiency and CF. The data demonstrate the feasibility of α1-PI inhalation for restoration of the impaired protease antiprotease balance, attenuation of the inflammation and neutralisation of the excess activity of NE. Likely, inhalation of α1-PI serves as cheaper and more convenient therapy than intravenous augmentation. However, inhalation will be further optimised by use of novel nebulisers and optimised breathing techniques.

Advances in hepatobiliary pathology: update for 2010

Recent publications on hepatology and hepatic pathology provide a wealth of new information on wideranging topics. Morphologic aspects of liver disease associated with hepatitis B and C viruses, autoimmune hepatitis, and HIV infection were addressed, as was the prevalent problem of nonalcoholic fatty liver disease. Advances in diagnosis and pathogenesis of primary biliary cirrhosis, primary sclerosing cholangitis, and the increasingly complex spectrum of IgG4 hepatobiliary diseases were also reported. The histologic and immunohistochemical features of the rare "calcifying nested stromal-epithelial tumor" of the liver were described in a 9-case series. For benign and malignant liver tumors, immunohistochemistry plays a major diagnostic role, and several recent studies demonstrate the value of immunostains in distinguishing between liver-cell adenoma and focal nodular hyperplasia.