An association between alpha 1-antitrypsin phenotype and chronic liver disease

The investigation of the frequency of the alpha-1-antitrypsin phenotype in patients with liver cirrhosis

OBJECTIVES

Alpha-1-antitrypsin (AAT) has different phenotypes. Evidence suggests that the abundance of each of these phenotypes may be associated with a disease. The purpose of this study was to evaluate the frequency of AAT phenotypes in patients with liver cirrhosis as well as in healthy individuals.

METHODS

In this study, 42 patients with liver cirrhosis were selected. The results of the previous research done by the researcher on healthy individuals were used to construct the control group. After obtaining informed consent, 5 mL of fasting venous blood sample was taken, and phenotypes were analyzed by isoelectric focusing. Data were analyzed using Chi-square and Fisher's exact tests at a significant level of 0.05.

RESULTS

The results of this study indicated that all 42 healthy subjects had an MM allele (100%). However, among 42 patients, 35 (83.3%) had an MM allele, 5 (11.9%) had an MS allele, and 2 (4.8%) had MZ allele. The difference between the two groups was significant (p=0.02). There was no difference between men and women in the allele type (p=0.557).

CONCLUSIONS

This study revealed that MS and MZ alleles were observed only in patients with liver cirrhosis, and none of these alleles were found in healthy subjects. Therefore, MS and MZ alleles can be further investigated as risk factors for liver cirrhosis.

Alpha-1-antitrypsin deficiency in Serbian adults with lung diseases

AIM

Alpha-1-antitrypsin (A1AT) is the main inhibitor of neutrophil elastase, and severe alpha-1-antitrypsin deficiency (A1ATD) is a genetic risk factor for early-onset emphysema. Despite the relatively high prevalence of A1ATD, this condition is frequently underdiagnosed. Our aim was to determine the distribution of the A1ATD phenotypes/alleles in patients with lung diseases as well as in the Serbian population.

METHODS

The study included the adults with chronic obstructive pulmonary disease (COPD) (n=348), asthma (n=71), and bronchiectasis (n=35); the control was 1435 healthy blood donors. The A1ATD variants were identified by isoelectric focusing or polymerase chain reaction-mediated site-directed mutagenesis.

RESULTS

PiMZ heterozygotes, PiZZ homozygotes, and Z allele carriers are associated with significantly higher risk of developing COPD than healthy individuals (odds ratios 3.43, 42.42, and 5.49 respectively). The calculated prevalence of PiZZ, PiMZ, and PiSZ was higher in patients with COPD (1:202, 1:8, and 1:1243) than in the Serbian population (1:5519, 1:38, and 1:5519).

CONCLUSION

The high prevalence of A1ATD phenotypes/allele in our population has confirmed the necessity of screening for A1ATD in patients with COPD. On the other hand, on the basis of the estimated number of those with A1ATD among the COPD patients, it is possible to assess the diagnostic efficiency of A1ATD in the Serbian population.

Alpha-1-antitrypsin deficiency in early childhood

Alpha-1-antitrypsin deficiency (AATD), which predisposes liver disease in children, is often undiagnosed. Isoelectric focusing in 161 infants with liver dysfunction revealed 14.7% severe and 12.2% moderate AATD. Positive PAS-D and immunohistochemical staining was found in 60% of severe AATD, but in moderate AATD, only immunohistochemistry was positive in 100%. Bilirubinostasis, hepatomegaly, splenomegaly, cholestasis, hepatomegaly associated with cholestasis, acholia, high transaminases, and low birthweight were significantly more frequent in severe than in moderate AATD. Both AATDs showed significant portal inflammation, hepatic fibrosis, and viral infection. Early screening in children with liver dysfunction can contribute to the successful detection of AATD.

Polymorphism of alpha-1-antitrypsin in hematological malignancies

Alpha-1-antitrypsin (AAT) or serine protease inhibitor A1 (SERPINA1) is an important serine protease inhibitor in humans. The main physiological role of AAT is to inhibit neutrophil elastase (NE) released from triggered neutrophils, with an additional lesser role in the defense against damage inflicted by other serine proteases, such as cathepsin G and proteinase 3. Although there is a reported association between AAT polymorphism and different types of cancer, this association with hematological malignancies (HM) is, as yet, unknown. We identified AAT phenotypes by isoelectric focusing (in the pH 4.2-4.9 range) in 151 serum samples from patients with HM (Hodgkins lymphomas, non-Hodgkins lymphomas and malignant monoclonal gammopathies). Healthy blood-donors constituted the control group (n = 272). The evaluated population of patients as well as the control group, were at Hardy-Weinberg equilibrium for the AAT gene (χ² = 4.42, d.f.11, p = 0.96 and χ² = 4.71, d.f.11, p = 0.97, respectively). There was no difference in the frequency of deficient AAT alleles (Pi Z and Pi S) between patients and control. However, we found a significantly higher frequency of PiM1M1 homozygote and PiM1 allele in HM patients than in control (for phenotype: f = 0.5166 and 0.4118 respectively, p = 0.037; for allele: f = 0.7020 and 0.6360 respectively, p = 0.05). In addition, PiM homozygotes in HM-patients were more numerous than in controls (59% and 48%, respectively, p = 0.044). PiM1 alleles and PiM1 homozygotes are both associated with hematological malignancies, although this is considered a functionally normal AAT variant.

Alpha-1-antitrypsin phenotypes in adult liver disease patients

Alpha-1-antitrypsin (AAT) is an important serine protease inhibitor in humans. Hereditary alpha-1-antitrypsin deficiency (AATD) affects lungs and liver. Liver disease caused by AATD in paediatric patients has been previously well documented. However, the association of liver disease with alpha-1-antitrypsin gene polymorphisms in adults is less clear. Therefore, we aimed to study AAT polymorphisms in adults with liver disease. We performed a case-control study. AAT polymorphisms were investigated by isoelectric focusing in 61 patients with liver cirrhosis and 9 patients with hepatocellular carcinoma. The control group consisted of 218 healthy blood donors. A significant deviation of observed and expected frequency of AAT phenotypes from Hardy-Weinberg equilibrium (chi-square = 34.77, df 11, P = 0.000) in the patient group was caused by a higher than expected frequency of Pi ZZ homozygotes (f = 0.0143 and f = 0.0005, respectively, P = 0.000). In addition, Pi M homozygotes were more frequent in patients than in controls (63% and 46%, respectively, P = 0.025). Our study results show that Pi ZZ homozygosity in adults could be associated with severe liver disease. Presence of Pi M homozygosity could be associated with liver disease via some mechanism different from Z allele-induced liver damage through accumulation of AAT polymers.

Isoelectric focusing phenotyping and denaturing gradient gel electrophoresis genotyping: a comparison of two methods in detection of alpha-1-antitrypsin variants

Laboratory diagnosis of alpha-1-antitrypsin (AAT) deficiency is routinely performed by phenotyping methods, which include measurement of serum alpha-1-antitrypsin concentration and isoelectric focusing (IEF). Several DNA-based methods are also used for AAT deficiency testing, but they still have not become part of routine diagnostics. The aim of the study was to identify AAT variants using 2 different methods, isoelectric focusing and denaturing gradient gel electrophoresis (DGGE), and to compare obtained results as well as practical application of these 2 methods. The study has encompassed 27 emphysema patients. In all patients, AAT phenotypization was conducted using IEF, whereas genotypization was performed by DGGE. Variations detected by DGGE were characterized by DNA sequencing. Mutations in the AAT gene were detected in 6 patients. Three patients were homozygous for the Z allele, whereas 1 patient was heterozygous. In 2 patients, novel AAT variants, G320R and V321F, were detected. When results obtained by IEF and DGGE were compared, it was observed that IEF results were inconclusive or misinterpreted in 5 cases (18.5%). Both methods proved to be reliable for detection of the Z alleles, whereas discrepancy existed for M4 allele and rare variants. Therefore, the optimal strategy for diagnostics of AAT deficiency should encompass detection of the most common AAT variants by IEF and screening for the less common variants by DGGE in combination with sequencing.

Association of moderate alpha-1 antitrypsin deficiency with lung cancer in the Serbian population

BACKGROUND

Alpha-1 antitrypsin (AAT) is an important serine protease inhibitor in human plasma. Its major physiological role is to inhibit neutrophil elastase (NE) in the lower respiratory tract and protect lung tissue from destruction. Recent studies indicated an etiological role of NE in lung cancer development. The aim of this study was to investigate the association of alpha-1 antitrypsin deficiency (AATD) with lung cancer in patients with four different histological types of cancer: squamous cell carcinoma, adenocarcinomas, large cell carcinoma and small cell carcinoma.

METHODS

Phenotyping was carried out by isoelectric focusing (pH 4.2-4.9). We compared the frequency of AATD phenotypes in 186 lung cancer patients with the value obtained in our previous study in a healthy Serbian population (3.7%) using the Fisher exact test.

RESULTS

Allele frequencies in patients were Pi *M 0.9677, Pi *Z 0.0215, Pi *S 0.0081 and Pi *other rare 0.0027. Eleven of the 186 lung cancer patients (5.9%) were AATD heterozygotes with moderate deficiencies (PiMZ and PiMS). When this value was compared with AATD heterozygote frequency obtained in the healthy individuals (3.7%), the difference was close to the level of significance (p = 0.055). However, individuals with AATD phenotypes had a higher risk of developing squamous cell lung cancer then those with non-deficient AAT variants (OR = 4.51, 95% CI = 1.66-12.29).

CONCLUSIONS

Our findings provide evidence of an association between AAT phenotypes with moderate deficiency and squamous cell lung cancer.

Factors associated with advanced liver disease in adults with alpha1-antitrypsin deficiency

BACKGROUND & AIMS

Alpha 1 -antitrypsin deficiency (AAT) is an autosomal recessive disease that affects 1 in 2500 persons and might lead to cirrhosis. Our study aim was to characterize the liver disease in AAT and identify factors associated with advanced liver disease.

METHODS

A cohort of the Alpha-1 Foundation Registry who reported liver disease was surveyed with a liver disease questionnaire to obtain information related to liver disease, liver transplantation, and AAT phenotype.

RESULTS

One hundred sixty-five of the 2175 participants in the registry reported a history of jaundice or liver disease, and 139 (84.2%) completed the questionnaire. Of these, 71.3% were PiZZ, 18.0% were PiMZ, and 5.7% did not know their phenotype. Analysis of 104 participants with a known age of diagnosis included 30 participants diagnosed with liver disease before 18 years, of whom 15 had advanced liver disease defined as liver transplantation or listed for liver transplantation. No differences in age, age at diagnosis, gender, race, phenotype, or infant jaundice were identified. Seventy-four participants were diagnosed after age 18 years, of whom 25 had advanced liver disease. In this group, advanced liver disease was associated with male gender ( P = .006) and a greater mean body mass index ( P = .01), but not with race, Pi phenotype, infant jaundice, diabetes, or hypercholesterolemia. Viral hepatitis was more frequently reported in the nontransplant group (34.7% vs 8.0%, P = .01), and the mean daily alcohol use was significantly greater in this group ( P = .04).

CONCLUSIONS

Our results suggest that male gender and obesity but not alcohol or viral hepatitis predispose to advanced liver disease in adults with AAT.

Reactive oxygen species, antiproteases, and cytokines in sepsis

Although the shock syndrome is recognized as a form of "mediator poisoning", a plethora of details is hardly converging into a coherent concept of chronological and molecular order. As a model for organ failure in septic shock, three alternative experimental approaches with a common pathology are presented: When galactosamine-sensitized mice receive either lipopolysaccharide or leukotriene D4 or tumor necrosis factor alpha they develop fulminant hepatitis within few hours with a lethal outcome within one day. Detailed pharmacological intervention studies allow to conclude that endotoxin-induced leukotriene D4 release induces a transient ischemia by the known vasoconstrictive action of this eicosanoid. A following reperfusion/reoxygenation phase gives rise to superoxide formation which inactivates alpha 1 proteinase inhibitor. Thus a serine protease becomes active which is responsible for the processing of a monocytic tumor necrosis factor alpha precursor to be released into the circulation after proteolytic cleavage. By this sequence the final central mediator of shock and sepsis becomes systematically abundant. The concept arising from these studies reconciles previously known findings and provides a link between the role of reactive oxygen species in inflammation, the balance of proteases and antiproteases in the extracellular space and the release of the cytokine tumor necrosis factor in sepsis and shock.