Association between serum gamma-glutamyltransferase and early-onset coronary artery disease: a retrospective case-control study.

BACKGROUND: Serum gamma-glutamyltransferase (GGT) activity has been proposed as a promising predictor of atherosclerosis-related complications and a prognostic marker for cardiovascular diseases. The objective of this study was to investigate the potential correlation between serum levels of GGT and early-onset coronary artery disease (EOCAD). METHODS: A retrospective, hospital-based case-control study was conducted, which included 860 patients with EOCAD and gender- and age-matched controls. Serum levels of GGT were measured using the reference measurement procedure on an automatic biochemistry analyser. RESULTS: The serum GGT levels of patients with EOCAD (34.90 ± 31.44 U/L) were significantly higher than those of the control group (21.57 ± 16.44 U/L, p < .001). Elevated serum levels of GGT were found to be an independent risk factor for EOCAD, with an odds ratio (OR) of 1.021 (95% confidence interval (CI): 1.014-1.029). Additionally, for every quartile increase in serum GGT levels, the risk of developing EOCAD increased by 1.6-fold. Moreover, serum GGT levels were significantly associated with disease severity, with lower GGT levels observed in patients without significant vascular disease (31.74 ± 24.06 U/L) compared to those with two-vessel disease (33.06 ± 25.00 U/L, p = .002) and three-vessel disease (37.75 ± 36.76 U/L, p = .001). CONCLUSIONS: The results of this study suggest that elevated serum GGT levels are associated with the development of EOCAD, and GGT may be implicated in the pathogenesis of the disease. Further large-scale prospective studies are needed to explore the potential relationship between serum GGT levels and the dynamic development of EOCAD.

Hematological parameters and early-onset coronary artery disease: a retrospective case-control study based on 3366 participants.

Background: Thrombosis and inflammation are crucial elements in the pathogenesis of cardiovascular disease. Hematological parameters elucidate information involving the inflammatory and blood coagulation processes. Objectives: The current study explored the association of hematological parameters with EOCAD to identify specific risk factors. Design: A single-center retrospective case-control study was conducted with 1693 coronary artery disease patients and 1693 controls. Methods: Hematological parameters were examined through an automated analyzer. Results: The basophil percentage was significantly reduced in EOCAD (0.43 ± 0.26, p < 0.001) and MI (0.33 ± 0.24, p < 0.001) groups compared with controls (0.54 ± 0.28). The eosinophil percentage was also significantly lower in EOCAD (2.21 ± 1.71, p < 0.001) and MI (1.71 ± 2.44, p < 0.001) groups compared with controls (2.41 ± 1.75). The lymphocyte percentage in patients of EOCAD and MI and controls was 31.65 ± 7.93, 25.48 ± 9.43, and 34.82 ± 7.28, respectively. A significant difference was observed among the groups (p < 0.001). Except for the mean corpuscular hemoglobin (MCH), other red blood cell (RBC) parameters significantly differed between EOCAD patients and controls. The red blood cell distribution width (RDW), hematocrit (HCT), RBC count, mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV), and hemoglobin level were associated with EOCAD prevalence after adjusting for baseline differences. Platelet volume distribution width (PDW) also correlated with EOCAD prevalence (ORadjust = 1.087, 95% CI: 1.044-1.131). Conclusions: Hematological parameters are closely associated with EOCAD. Moreover, leukocyte parameters correlated with the presence and severity of the disease. In addition, erythrocyte parameters were associated with the disease presence but not with the disease severity. Among the platelet parameters, only PDW was related to the disease presence.

Serum fatty acids profile and association with early-onset coronary artery disease.

BACKGROUND: Fatty acids (FAs) play crucial roles in modulating and preventing diseases in humans, including early-onset coronary artery disease (EOCAD). In this study, we aimed to provide a profile of FAs in the serum of EOCAD patients and identify potential EOCAD-associated FAs. METHODS: In the first stage, we analyzed the FAs profiles in pooled samples of patients with EOCAD using gas chromatography-mass spectrometry. In the second stage, the serum levels of the candidate FAs were validated in EOCAD patients. RESULTS: A total of 128 EOCAD patients and 64 controls were included in the study. Forty-nine serum FAs were quantified in pooled samples; three ω-3 FAs were identified to be associated with EOCAD. Moreover, results from the validation stage indicated that serum levels of docosahexaenoic acid (DHA) were significantly lower in EOCAD patients (55.43 ± 33.86 µg/ml) and myocardial infarction (MI) patients (47.49 ± 28.44 µg/ml) than those in the controls (70.65 ± 43.56 µg/ml). Multivariate regression analysis revealed that elevated serum DHA level was an independent protective factor for EOCAD [odds ratio (OR) = 0.8917, 95% confidence interval (CI): 0.879-0.957] and MI (OR = 0.835, 95% CI: 0.799-0.862). Decreased serum levels of docosapentaenoic acid (DPA) and eicosapentaenoic acid (EPA) were observed in the early-onset MI group. CONCLUSION: The study provided the serum FAs profile of EOCAD and confirmed that the decrease in serum levels of DHA, DPA, and EPA was associated with EOCAD. These findings might contribute to understanding the cardiovascular effects of FAs, particularly the protective effects of ω-3 polyunsaturated FAs.

Quantitative Assessment of Serum Amino Acids and Association with Early-Onset Coronary Artery Disease.

BACKGROUND: Amino acids play essential roles in protein construction and metabolism. Our study aims to provide a profile of amino acid changes in the serum of patients with early-onset coronary artery disease (EOCAD) and identify potential disease biomarkers. METHODS: Ultra-performance liquid chromatography-multiple reaction monitoring-multistage/mass spectrometry (UPLC-MRM-MS/MS) was used to determine the amino acid profile of patients with EOCAD in sample pools. In the validation stage, the serum levels of candidate amino acids of interest are determined for each sample. RESULTS: A total of 128 EOCAD patients and 64 healthy controls were included in the study. Eight serum amino acids associated with disease state were identified. Compared with the control group, serum levels of seven amino acids (L-Arginine, L-Methionine, L-Tyrosine, L-Serine, L-Aspartic acid, L-Phenylalanine, and L-Glutamic acid) increased and one (4-Hydroxyproline) decreased in the patient group. Results from the validation stage demonstrate that serum levels of 4-Hydroxyproline were significantly lower in myocardial infarction (MI) patients (9.889 ± 3.635 µg/mL) than those in the controls (16.433 ± 4.562 µmol/L, p < 0.001). Elevated serum 4-Hydroxyproline levels were shown to be an independent protective factor for MI (OR = 0.863, 95% CI: 0.822-0.901). The significant negative correlation was seen between serum 4-Hydroxyproline levels and cardiac troponin I (r = -0.667) in MI patients. CONCLUSION: We have provided a serum amino acid profile for EOCAD patients and screened eight disease state-related amino acids, and we have also shown that 4-Hydroxyproline is a promising target for further biomarker studies in early-onset MI.

Association Between MTHFR Gene Common Variants, Serum Homocysteine, and Risk of Early-Onset Coronary Artery Disease: A Case-Control Study.

The common variants of the methylenetetrahydrofolate reductase (MTHFR) gene are related to the activity of the MTHFR enzyme and the concentrations of blood homocysteine (Hcy). This study was designed to investigate the associations of MTHFR in Chinese populations with early-onset coronary artery disease (EOCAD). The two common variants of the MTHFR gene were genotyped in 875 EOCAD patients and 956 controls using PCR, followed by direct sequencing of the PCR product. Serum levels of Hcy were measured using an automatic biochemistry analyzer. A significant association between the MTHFR-677C/T variant and the risk of EOCAD was detected in CC versus TT (odds ratio (OR) 1.456, 95% confidence interval (CI) 1.120-1.892), dominant genetic model (OR 1.266, 95% CI 1.027-1.546), and recessive genetic model (OR 1.306, 95% CI 1.040-1.639). Hcy was most abundant in TT genotype (18.31 ± 7.22 µmol/L), least abundant in CC genotype (11.37 ± 5.23 µmol/L), and detectable at intermediate levels in heterozygotes (15.25 ± 6.58 µmol/L). Elevated serum Hcy levels were an independent risk factor for EOCAD (ORadjust 1.431, 95% CI 1.135-1.763). Our findings indicated that the T allele of -677C/T MTHFR variant predisposes to high levels of Hcy, and that the T allele is an important risk factor for EOCAD in the Chinese population.

Serum adenosine deaminase activity and coronary artery disease: a retrospective case-control study based on 9929 participants.

BACKGROUND: Adenosine deaminase (ADA) regulates purine metabolism through the conversion of adenosine to uric acid (UA). Adenosine and UA are closely associated with cardiovascular events, but the correlation between serum ADA activity and coronary artery disease (CAD) has not been defined. METHODS: We performed a hospital-based retrospective case-control study that included a total of 5212 patients with CAD and 4717 sex- and age-matched controls. The serum activity of ADA was determined by peroxidase assays in an automatic biochemistry analyzer. RESULTS: Serum ADA activity in the CAD group (10.08 ± 3.57 U/l) was significantly lower than that of the control group (11.71 ± 4.20 U/l, p < 0.001). After adjusting for conventional factors, serum ADA activity negatively correlated with the presence of CAD (odds ratio = 0.852, 95% confidence interval: 0.839-0.865, p < 0.001). Among the patients with CAD, serum ADA activity was lowest in patients with myocardial infarction (MI; 9.77 ± 3.80 U/l). Diabetes mellitus and hypertension increased the serum ADA activity in CAD patients. CONCLUSIONS: Serum ADA activity is significantly attenuated in patients with CAD, particularly in MI. We propose a mechanism by which the body maintains adenosine levels to protect the cardiovascular system in the event of CAD.

Screening and Identification of Pregnancy Zone Protein and Leucine-Rich Alpha-2-Glycoprotein as Potential Serum Biomarkers for Early-Onset Myocardial Infarction using Protein Profile Analysis.

PURPOSE: The present study aims to discover novel serum biomarkers of early-onset myocardial infarction (MI) using proteomic analysis. EXPERIMENTAL DESIGN: In the first stage, the iTRAQ-coupled LC-MS/MS technique is utilized to investigate protein profiles of patients with early-onset MI. In the second stage, these candidate proteins are validated using ELISA. RESULTS: A total of 538 proteins are quantified, with pregnancy zone protein (PZP), leucine-rich α-2-glycoprotein (LRG) and Apolipoprotein C-I (Apo C-I) being upregulated and Apolipoprotein A-I (Apo A-I) and Apolipoprotein A-IV (Apo A-IV) downregulated in early-onset MI patients. Results from the validation stage demonstrate that the serum concentrations of PZP and LRG are significantly increased in the early-onset MI group. The correlation between the concentrations of C-reactive protein (CRP) and the two candidate biomarkers is positive. Area under the curve values used to diagnose early-onset MI for LRG and PZP are 0.939 and 0.874, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Five differential serum proteins are identified in early-onset MI using proteomic analysis. Lipoprotein-related biomarkers further demonstrate the close relationship between lipid metabolism and the disease. Inflammation-associated LRG and PZP may be novel biomarkers of the disease. In addition, changes in these proteins may partly reveal the possible mechanisms in the pathogenesis and pathophysiology of early-onset MI.

Serum Uric Acid as an Independent Risk Factor for the Presence and Severity of Early-Onset Coronary Artery Disease: A Case-Control Study.

Serum uric acid (UA) is the final product of purine metabolism in humans. The present study is aimed at identifying the potential association between serum UA and early-onset coronary artery disease (EOCAD). The study population consisted of 1093 EOCAD patients aged ≤50 years, and 1117 age- and sex-matched apparently healthy people served as controls. The concentrations of UA were measured by uricase method. The severity of CAD was evaluated by Gensini score. The mean serum level of UA was 5.843 ± 1.479 mg/dl in EOCAD patients and 5.433 ± 1.529 mg/dl in controls. Serum UA levels were significantly higher in the EOCAD group than those in the control group (P < 0.001) and was an independent risk factor for EOCAD (OR = 1.100, 95% CI: 1.022-1.185). The early-onset myocardial infarction patients with 3-vessel disease had higher serum UA levels than those with 1- or 2-vessel disease. The serum UA levels of EOCAD patients with acute coronary syndrome were significantly higher than those with chronic coronary artery disease. EOCAD patients with hyperuricemia had higher Gensini scores than those without hyperuricemia. In addition, the serum UA levels were affected by drinking (P < 0.01) and were positively correlated with serum creatinine (r = 0.323) and weight (r = 0.327). Our results show that serum UA was an independent risk factor for EOCAD. The serum UA levels were associated with the presence and severity of EOCAD and suggested that UA may be involved in the progression of EOCAD.

Increased serum concentrations of asymmetric dimethylarginine (ADMA) in patients with early-onset coronary artery disease.

BACKGROUND: Asymmetric dimethylarginine (ADMA) has been associated with an increased risk of cardiovascular disease. We investigated the role of serum ADMA concentrations in early-onset coronary artery disease (EOCAD). METHODS: Candidates for coronary artery angiography (age<50y for men and <55y for women) who met the inclusion criteria were enrolled in this study. Serum concentrations of ADMA were determined using ELISA. Severity of coronary atherosclerosis was estimated by number of diseased vessels. RESULTS: A total of 601 subjects (286 with EOCAD patients and 315 controls) were included in the study. ADMA concentrations were found to be significantly higher in the EOCAD group (0.480±0.110µmol/l) than in the control group (0.457±0.091, P=0.007). ADMA concentrations significantly increased with the number of diseased vessels (P<0.001). In addition, serum ADMA concentrations were affected by diabetes mellitus and smoking status, and were positively correlated with serum creatinine and body mass index (BMI). CONCLUSIONS: Our results show that serum ADMA concentrations were associated with the presence and severity of EOCAD, suggesting that ADMA may be involved in the progression of EOCAD.

Dimethylarginine Dimethylaminohydrolase 2 (DDAH 2) Gene Polymorphism, Asymmetric Dimethylarginine (ADMA) Concentrations, and Risk of Coronary Artery Disease: A Case-Control Study.

Asymmetric dimethylarginine (ADMA) has been shown to be an independent predictor of cardiovascular diseases. Dimethylarginine dimethylaminohydrolase 2 (DDAH 2) promotes the metabolism of ADMA and plays a key role in the regulation of acute inflammatory response. With the present study, we investigated the relationship between DDAH 2 polymorphisms and risk of coronary artery disease (CAD) and its association to plasma ADMA concentrations. We used the haplotype-tagging SNP approach to identify tag SNPs in DDAH 2. The SNPs were genotyped by PCR and sequenced in 385 CAD patients and 353 healthy controls. Plasma concentrations of ADMA were determined using enzyme-linked immunosorbent assay (ELISA). A promoter polymorphism -449C/G (rs805305) in DDAH 2 was identified. Compared with the ADMA concentrations in CC genotype (0.328 ± 0.077 µmol/l), ADMA concentrations in CG + GG genotype were significantly increased (0.517 ± 0.090 µmol/l, P < 0.001). No significant associations between the -449C/G and risk of CAD were detected in the genetic models. The results of this study suggest that Genetic -499C/G polymorphism in DDAH 2 gene may affect the plasma ADMA concentrations in patients with CAD. However, it does not indicate a novel genetic risk marker for CAD.

Levels of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, and risk of coronary artery disease: A meta-analysis based on 4713 participants.

BACKGROUND: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide synthase by competing with L-arginine. As a result, the expression of nitric oxide decreases and endothelial dysfunction occurs. Studies have evaluated the association between the serum ADMA level and risk of coronary artery disease. However, conflicting results have been obtained. METHODS: Pubmed, Web of Science, Embase, Ovid, Cochrane databases were searched to identify eligible studies published in English until December 2014. Association was assessed on the basis of weighted mean differences (WMD) with 95% confidence intervals (CIs). Publication bias was analysed using Begg's and Egger's tests. Sensitivity analysis was performed to evaluate result stability. RESULTS: A total of 16 case-control studies with 2939 patients and 1774 controls were included in the meta-analysis. Pooled result indicated that patients with coronary artery disease yielded a higher ADMA level than healthy controls (WMD: 0.248, 95% CI: 0.156-0.340; p = 1.16 e-7). Sensitivity analysis suggested that our meta-analysis result was stable. Subgroup analysis found a similar pattern in patients with myocardial infarction (WMD: 0.397, 95% CI: 0.112-0.683; p = 0.0106), stable angina pectoris (WMD: 0.197, 95% CI: 0.031-0.364; p = 0.02) and unstable angina pectoris (WMD: 0.857, 95% CI: 0.293-1.420; p = 0.003). CONCLUSIONS: Meta-analysis results indicated that an increased ADMA level is associated with an increased risk of coronary artery disease.

L-citrulline for protection of endothelial function from ADMA-induced injury in porcine coronary artery.

Endogenous nitric oxide synthase (eNOS) inhibitor asymmetric dimethylarginine (ADMA) is a cardiovascular risk factor. We tested the hypothesis that L-citrulline may ameliorate the endothelial function altered by ADMA in porcine coronary artery (PCA). Myograph study for vasorelaxation, electrochemical measurement for NO, RT-PCR, and Western blot analysis for expression of eNOS, argininosuccinate synthetase (ASS), and p-eNOS(ser1177) were performed. cGMP was determined by enzyme immunoassay. Superoxide anion (O2.(-)) production was detected by the lucigenin-enhanced chemiluminescence method. Compare with controls (96.03% ± 6.2%), the maximal relaxation induced by bradykinin was significantly attenuated (61.55% ± 4.8%, p<0.01), and significantly restored by L-citrulline (82.67 ± 6.4%, p<0.05) after 24 hours of ADMA exposure. Expression of eNOS, p-eNOS(ser1177), and ASS in PCA significantly increased after L-citrulline incubation. L-citrulline also markedly restored the NO production, and cGMP level which was reduced by ADMA. The increased O2.(-) production by ADMA was also inhibited by L-citrulline. L-citrulline restores the endothelial function in preparations treated with ADMA by preservation of NO production and suppression of O2.(-) generation. Preservation of NO is attributed to the upregulation of eNOS expression along with activation of p-eNOS(ser1177). L-citrulline improves endothelium-dependent vasodilation through NO/ cGMP pathway.

Association between MTHFR polymorphisms and congenital heart disease: a meta-analysis based on 9,329 cases and 15,076 controls.

The aim of our study was to evaluate the association between polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and the risk for congenital heart disease (CHD). Electronic literature databases were searched to identify eligible studies published before Jun, 2014. The association was assessed by the odds ratio (OR) with a 95% confidence interval (CI). The publication bias was explored using Begg's test. Sensitivity analysis was performed to evaluate the stability of the crude results. A total of 35 studies were included in this meta-analysis. For the MTHFR C677T polymorphism, we detected significant association in all genetic models for Asian children and the maternal population. Significant association was also detected in T vs. C for a Caucasian paediatric population (OR = 1.163, 95% CI: 1.008-1.342) and in both T vs. C (OR = 1.125, 95% CI: 1.043-1.214) and the dominant model (OR = 1.216, 95% CI:b1.096-1.348) for a Caucasian maternal population. For the MTHFR A1298C polymorphism, the association was detected in CC vs. AC for the Caucasian paediatric population (OR = 1.484, 95% CI: 1.035-2.128). Our results support the MTHFR -677T allele as a susceptibility factor for CHD in the Asian maternal population and the -1298 C allele as a risk factor in the Caucasian paediatric population.

Diagnostic accuracy of glycosylated hemoglobin in chinese patients with gestational diabetes mellitus: a meta-analysis based on 2,812 patients and 5,918 controls.

BACKGROUND AND AIMS: The accuracy of glycosylated hemoglobin (HBA1c) detection for the diagnosis of gestational diabetes mellitus (GDM) has been extensively studied in the Chinese population, but the exact role of these detections remains controversial. The present meta-analysis was performed to establish the overall accuracy of HBA1c for the diagnosis of Chinese patients with GDM. METHODS: After a systematic review of related studies, the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and other measures about the accuracy of HBA1c in the diagnosis of GDM were pooled using random-effects models. The summary receiver operating characteristic (SROC) curve analysis was used to summarize the overall test performance. RESULTS: Forty-one studies included 2812 Chinese patients with GDM and 5918 controls were included in our meta-analysis. The summary estimates for HBA1c in the diagnosis of GDM in the studies included were as follows: sensitivity 0.762 (95% confidence interval [CI]: 0.746-0.777), specificity 0.917 (95% CI: 0.910-0.924), PLR 8.21 (95% CI: 3.77-17.89), NLR 0.20 (95% CI: 0.09-0.44), and DOR 41.40 (95% CI: 11.47-149.38). Our data showed that the SROC curve is positioned near the desirable upper left corner of the SROC curve, while the area under curve (AUC) was 0.93 with a Q* value of 0.865. CONCLUSIONS: Measurement of HBA1c is likely to be a useful diagnostic tool for confirming GDM. The results of HBA1c should be interpreted in parallel with clinical findings and the results of conventional tests.

PTPN22 gene polymorphism (C1858T) is associated with susceptibility to type 1 diabetes: a meta-analysis of 19,495 cases and 25,341 controls.

The protein tyrosine phosphatase N22 (PTPN22) gene C1858T polymorphism has been reported to be associated with susceptibility to type 1 diabetes (T1D) in relatively small sample sizes. This study aimed at investigating the pooled association by carrying out a meta-analysis on the published studies. The Medline, EBSCO, and BIOSIS databases were searched to identify eligible studies published in English before June 2012. The association was assessed by odds ratio (OR) with 95% confidence intervals (CI). The presence of heterogeneity and publication bias was explored by using meta-regression analysis and Begg's test, respectively. A total of 28 studies were involved in this meta-analysis. Across all populations, significant associations were found between the PTPN22 C1858T polymorphism and susceptibility to T1D under genotypic (TT vs. CC [OR = 3.656, 95% CI: 3.139-4.257], CT vs. CC [OR = 1.968, 95% CI: 1.683-2.300]), recessive (OR = 3.147, 95% CI: 2.704-3.663), and dominant models (OR = 1.957, 95% CI: 1.817-2.108). In ethnicity- and sex-stratified analyses, similar associations were found among Caucasians and within Caucasian male and female strata. The meta-analysis results suggest that the PTPN22 C1858T polymorphism was associated with susceptibility to T1D among the Caucasian population, and males who carried the -1858T allele were more susceptible to T1D than females.

Polymorphism of DNA repair gene XRCC1 and hepatocellular carcinoma risk in Chinese population.

AIM: We conducted a case-control study in China to clarify the association between the XRCC1-Arg399Gln polymorphism and HCC risk. METHODS: A total of 202 cases and 236 controls were selected from the the Affiliated Hospital of Qingdao University from May 2008 to May 2010. Assessment of the XRCC1-Arg399Gln polymorphism was based upon duplex polymerase-chain-reactions with the confronting-two-pair primer (PCR- CTPP) method. All analyses were performed using the STATA statistical package. RESULTS: A significant increase in risk was associated with the Arg/Gln genotype (adjusted OR 1.55, 95%CI=1.03-2.57) compared with Arg/ Arg. However, the Gln/Gln genotype had non-significant increased risk of HCC with adjusted OR (95%CI) of 1.34(0.67-2.38). There was also a significant increase with the Arg/Gln genotype among HCC patients above 50 years old (OR=1.95, 95% CI=1.14-3.57). Additionally, the risk of HCC was moderately increased in drinkers with Arg/Gln genotype compared with never drinkers, and the adjusted OR (95% CI) was 1.89 (1.13-3.45). CONCLUSION: This study demonstrated that a polymorphism in a DNA repair gene may influence the risk of HCC. The XRCC1 codon Arg/Gln was this associated with an increased risk of HCC, especially in patients above 50 years old and/or with a drinking habit.

Alanine aminotransferase in amphioxus: Presence, localization and up-regulation after acute lipopolysaccharide exposure.

Alanine aminotransferase (AAT) is mainly synthesized in the liver, and its level in mammalian serum is elevated after acute phase induction. Here we demonstrated that sheep anti-human AAT antibody cross-reacted with amphioxus humoral fluids as well as human serum; and the concentration of AAT in the humoral fluids in amphioxus increased after the acute challenge with lipopolysaccharide, while the level of total proteins remains unchanged. These suggest the presence of the same acute phase response pattern in amphioxus, as observed in some mammalian species. Immunohistochemically, AAT was localized in the hepatic diverticulum, ovary and testis. It appears that the hepatic diverticulum in amphioxus is functionally homologous to the vertebrate liver in respect of AAT synthesis, supporting the hypothesis that the vertebrate liver evolved from the hepatic diverticulum of an amphioxus-like ancestor during early chordate evolution.