Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cellular changes that occur within the liver before and during liver fibrosis have been studied. At various times (0-90 days) after gamma irradiation (0-25 Gy) of the whole liver, hepatocytes and liver nonparenchymal cells were isolated by enzymatic dissociation of the liver and differential centrifugation. Differential cell counts were done to quantify the yield of hepatocytes and nonparenchymal cells. Hepatocyte function in vitro was assayed by the uptake of rose bengal and compared with the clearance of the dye in vivo. Intracellular alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were used to estimate the effect of radiation on the phenotypic expression of hepatocytes. Gene expression of transforming growth factor beta 1 (TGF-beta 1), a cytokine which has been found to play a role in hepatic fibrosis, was measured by 32P-cDNA:mRNA hybridization of poly(A+) mRNA isolated from purified populations of hepatocytes and nonparenchymal cells. Morphologically, hemorrhages were evident in perfused livers 28 days after 25 Gy whole-liver irradiation. This injury was preceded by a significant increase in liver nonparenchymal cells at 2 weeks, the earliest time after irradiation at which measurements were made. Significant increases in liver nonparenchymal cells occurred at doses greater than 10 Gy and persisted throughout the follow-up period after irradiation. The lowest dose studied (5 Gy) inhibited both normal growth of the liver and the associated increase in the number of hepatocytes. Doses greater than 10 Gy resulted in a dose-dependent decline in liver mass and hepatocytes. Viable hepatocytes isolated from irradiated dysfunctional livers, with respect to clearance of rose bengal, were functionally normal in vitro. A dose-dependent decline in the ALT and AST contents of liver cell suspensions and homogenates was observed but the relative decline in ALT was greater, resulting in lower ALT/AST ratios. This decline in the ALT/AST ratios occurred at doses (< 15 Gy) which caused no loss of hepatocytes, suggesting possible conversion of ALT-rich periportal hepatocytes to ALT-poor hepatocytes due to changes in the microenvironment and/or aging of the cell population. TGF-beta 1 mRNA was detected mainly in nonparenchymal cells, and radiation preferentially enhanced the TGF-beta 1 gene expression in these cells. These data suggest that radiation-induced alterations in liver nonparenchymal cell populations may be responsible for microvascular fibrosis, which results in a cascade of pathological events which lead to hepatocyte loss.
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PMID:Radiation hepatology of the rat: parenchymal and nonparenchymal cell injury. 824 77

Somatic mutations in the transforming growth factor beta receptor type II (TGF-beta RII) gene have been observed in various human cancers showing microsatellite instability. Most of the mutations observed were additions or deletions of the mononucleotide repeat sequence present in TGF-beta RII coding region, suggesting that the TGF-beta RII may be a target gene of genomic instability in tumorigenesis. Recently, we reported germ-line frameshift mutations in the mononucleotide repeat sequence of the hMSH6 gene, which is believed to be one of the target genes of genomic instability in tumorigenesis, suggesting the possibility of germ-line mutation in mononucleotide repeat sequences. Moreover, one case of germ-line mutation in the TGF-beta RII gene was identified in a hereditary nonpolyposis colorectal cancer (HNPCC) kindred, indicating the involvement of TGF-beta RII inactivation in tumorigenesis of HNPCC. However, germ-line mutation analysis of all of the coding sequences and the mononucleotide repeat sequence of the TGF-beta RII in HNPCC patients has not yet been fully elucidated. Therefore, to further investigate the presence of germ-line mutations, we screened all of the coding region sequences and mononucleotide repeat sequence of TGF-beta RII from 35 HNPCC, 44 suspected HNPCC, and 45 sporadic early-onset colorectal cancer patients. However, no pathogenic mutations other than silent mutations, introgenic mutation, and polymorphisms were identified. Two silent mutations at codons 309 (ACG to ACA) and 340 (CAT to CAC) in the kinase domain located in exon 4 were detected. A 1-bp cytidine deletion was observed 6 bases from the 3' end of intron. Two polymorphisms were identified at codon 389 (AAC to AAT) and at the fourth-to-last base in intron 3. The polymorphism at codon 389 was more frequent in HNPCC (20%; 7 of 35) and suspected HNPCC patients (18%; 8 of 44) than in nonmalignant control group (10%; 5 of 50). Moreover, the frequency was significantly higher in early-onset colorectal cancer patients (31%; 14 of 45). This is the first report of a different frequency of polymorphism in HNPCC, suspected HNPCC, early-onset colorectal cancer patients, and healthy normal individuals. This result suggests that: (a) germ-line mutation of the TGF-beta RII gene may be a rare event during tumorigenesis in HNPCC and sporadic early-onset colorectal cancer; (b) the mononucleotide repeat sequence of the TGF-beta RII gene is an apparent target of genomic instability but not of germ-line mutation; and (c) the polymorphism of codon 389 (AAC to AAT) is frequent, especially in early-onset colorectal cancer patients, in which it is more frequent than in control group.
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PMID:Mutational analysis of the transforming growth factor beta receptor type II gene in hereditary nonpolyposis colorectal cancer and early-onset colorectal cancer patients. 1069 May 36

Diabetic nephropathy is a common cause of end-stage renal disease. The administration of an oral adsorbent, AST-120, prevents the progression of chronic renal failure in uremic rats and undialyzed uremic patients. This study was designed to determine if AST-120 slows the progression of diabetic nephropathy using Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of non-insulin-dependent diabetic mellitus. At 21 weeks of age the OLETF rats were divided into 2 groups: AST-120-administered OLETF rats (n = 7), and control OLETF rats (n = 7). LETO rats, which are genetically similar to the OLETF rats but not diabetic, were also included. After the oral administration of AST-120 for 65 weeks, renal function and pathological changes were investigated in the 3 groups. The administration of AST-120 to the OLETF rats attenuated the progression of glomerular sclerosis, interstitial fibrosis, tubular injury as well as renal dysfunction, and reduced the serum and urinary levels of indoxyl sulfate. Furthermore, AST-120 administration reduced the interstitial expression of transforming growth factor (TGF)-beta(1) and tissue inhibitor of metalloproteinase (TIMP)-1, as well as interstitial infiltration of macrophages. The TGF-beta(1)-stained interstitial area showed positive correlations with the interstitial fibrosis area, the number of TIMP-1-positive cells, and the number of macrophages, and showed a negative correlation with creatinine clearance. In conclusion, AST-120 reduced the interstitial expression of TGF-beta(1) and TIMP-1, and the interstitial infiltration of macrophages, and ameliorates the progression of diabetic nephropathy in OLETF rats.
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PMID:Oral adsorbent AST-120 ameliorates interstitial fibrosis and transforming growth factor-beta(1) expression in spontaneously diabetic (OLETF) rats. 1087 8

Cutaneous leg ulcers are common in sickle cell anaemia and their risk might be genetically determined. Sickle cell anaemia patients were studied to examine the relationship of leg ulcers with haemolysis and with single nucleotide polymorphisms (SNPs) in candidate genes that could affect sickle vasoocclusion. Leg ulcer patients had lower haemoglobin levels and higher levels of lactate dehydrogenase, bilirubin, aspartate transaminase and reticulocytes than did control patients with sickle cell anaemia but without leg ulcers. Age-adjusted comparisons showed that sickle cell anaemia-alpha thalassaemia was more frequent among controls than cases. These results strongly suggested that the likelihood of having leg ulcers was related to the intensity of haemolysis. 215 SNPs in more than 100 candidate genes were studied. Associations were found with SNPs in Klotho, TEK and several genes in the TGF-beta/BMP signalling pathway by genotypic association analyses. KL directly or indirectly promotes endothelial nitric oxide (NO) production and the TEK receptor tyrosine kinase is involved in angiogenesis. The TGF-beta/BMP signalling pathway modulates wound healing and angiogenesis, among its other functions. Haemolysis-driven phenotypes, such as leg ulcers, could be improved by agents that reduce sickle erythrocyte density or increase NO bioavailability.
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PMID:Sickle cell leg ulcers: associations with haemolysis and SNPs in Klotho, TEK and genes of the TGF-beta/BMP pathway. 1668 47

To assess the effects of anti-TNF-alpha antibody (infliximab) in experimental steatohepatitis induced by methionine- and choline-deficient (MCD) diet. The study included thirty rats. One group received normal rat food, and two groups received MCD diet. The treatment group received a single dose intra-peritoneal infliximab (4 mg/kg), at week 8. MCD diet increased levels of AST, ALT, TNF-alpha, TGF-beta(1), tissue and plasma MDA (p < 0.05 for each). Moreover, it led to steatosis, ballooning degeneration, inflammation, fibrosis and increased actin expression, histopathologically (p < 0.05 for each). In this experimental steatohepatitis anti-TNF-alpha antibody decreased the levels of AST, ALT, TGF-beta(1) and plasma and tissue MDA (p < 0.05 for each). Moreover, inflammation, necrosis, actin expression and fibrosis decreased in anti-TNF-alpha group compared to placebo group (p < 0.05 for each). This study indicates that anti-TNF-alpha antibody is effective on necrosis, inflammation and fibrosis in the experimental model of non-alcoholic steatohepatitis, induced by MCD diet.
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PMID:The treatment with antibody of TNF-alpha reduces the inflammation, necrosis and fibrosis in the non-alcoholic steatohepatitis induced by methionine- and choline-deficient diet. 1806 56

Many factors could potentially affect the process of arsenic-induced liver fibrosis. The present study was undertaken to examine the effect of high fat diet on arsenic-induced liver fibrosis and preneoplastic changes. Mice were given sodium arsenite (As3+, 200 ppm) or sodium arsenate (As5+, 200 ppm) in the drinking water for 10 months, and provided a normal diet or a diet containing 20% added fat. Serum aspartate aminotransferase (AST), indicative of liver injury, was elevated in both arsenite and arsenate groups, and a high fat diet further increased these levels. Histopathology (H&E and Masson stain) showed that liver inflammation, steatosis (fatty liver), hepatocyte degeneration, and fibrosis occurred with arsenic alone, but their severity was markedly increased with the high fat diet. Total liver RNA was isolated for real-time RT-PCR analysis. Arsenic exposure increased the expression of inflammation genes, such as TNF-alpha, IL-6, iNOS, chemokines, and macrophage inflammatory protein-2. The expression of the stress-related gene heme oxygenase-1 was increased, while metallothionein-1 and GSH S-transferase-pi were decreased when arsenic was combined with the high fat diet. Expression of genes related to liver fibrosis, such as procollagen-1 and -3, SM-actin and TGF-beta, were synergistically increased in the arsenic plus high fat diet group. The expression of genes encoding matrix metalloproteinases (MMP2, MMP9) and tissue inhibitors of metalloproteinases (TIMP1, TIMP2) was also enhanced, suggestive of early oncogenic events. In general, arsenite produced more pronounced effects than arsenate. In summary, chronic inorganic arsenic exposure in mice produces liver injury, and a high fat diet markedly increases arsenic-induced hepatofibrogenesis.
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PMID:High dietary fat exacerbates arsenic-induced liver fibrosis in mice. 1829 43

Morin, a plant-derived flavonoid, has been reported to exhibit a wide range of pharmacological properties. In this study, we investigated the protective effect of morin on hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. Oral administration of morin remarkably prevented weight loss in the body and liver from DMN and inhibited the elevation of serum alanine transaminase (ALT), aspartate transaminase (AST), and total bilirubin levels. For the evaluation of hepatic fibrosis-related factors, we investigated expressions of collagen type I, transforming growth factor beta(1) (TGF-beta(1)), and alpha-smooth muscle actin (alpha-SMA) in mRNA and protein levels. We observed that morin significantly reduced the expression of collagen type I, TGF-beta(1), and alpha-SMA on hepatic fibrosis induced by DMN. Taken together, this study demonstrated that morin showed hepatoprotective and antifibrogenic effects against DMN-induced hepatic injury. This suggests that morin may be useful in preventing the development of hepatic fibrosis and cirrhosis.
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PMID:Protective effect of morin on dimethylnitrosamine-induced hepatic fibrosis in rats. 1862 40

Reperfusion injury causes liver dysfunction after warm or cold ischemia. Emerging data suggest a role of T cells as mediators in this ischemia/reperfusion (I/R) injury. In the T cells, a part of CD4(+)CD25(+)FoxP3(+) T regulatory cells (Tregs) were reported to facilitate recovery from I/R injury. These Tregs can be induced by TGF-beta in vitro. Interestingly, rapamycin was reported to selectively expand these Tregs in vitro. In the present study, addition of rapamycin to cultures containing TGF-beta further increased the frequency and absolute number of functional CD4(+) Tregs. Using a partial (70%) hepatic warm ischemia model, we investigated the effects of liver function recovery under the treatment of Tregs induced by rapamycin and TGF-beta. The treatment of Tregs significantly reduced serum alanine aminotransferase and aspartate aminotransferase compared to I/R control animals at 24 h after reperfusion (P<0.05). They also significantly attenuated the up-regulation of IFN-gamma and IL-17 compared to the I/R control animals (P<0.05). In conclusion, Tregs ameliorate the biochemical of hepatic I/R injury by preventing proinflammatory cytokines following a warm I/R insult. These data may pave the way to use Tregs as cell therapy to prevent hepatic I/R injury.
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PMID:In vitro induced CD4(+)CD25(+)Foxp3(+) Tregs attenuate hepatic ischemia-reperfusion injury. 1953 64

Sickle cell anemia (SCA) is characterized by a marked endothelial dysfunction, owing to many factors. Arginine metabolism can be related to the inflammatory chronic state presented by patients, playing a key role in their clinical outcome and vascular endothelium. We investigated the serum arginase levels in 50 SCA patients (22 men and 28 women, mean age of 17 +/- 10.5 years) and 28 healthy controls. Serum arginase levels were associated with biochemical hemolysis markers and cytokines involved in Th17 response, as well as levels of soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1). Arginase concentrations were higher in SCA patients, compared with controls (p = 0.005), and were significantly and positively associated with total bilirubin (p = 0.004), indirect bilirubin (p = 0.04), and aspartate aminotransferase (AST; p = 0.039) in the SCA patient group. Moreover, arginase was significantly and positively associated with transforming growth factor-beta (TGF-beta; p = 0.008) among SCA patients. sICAM-1 was significantly and positively associated to reticulocytes (p = 0.014) and AST (p = 0.04). sVCAM-1 was likewise associated with lactate dehydrogenase (p = 0.03). These data suggest a new insight into arginase metabolism, as we show here a shift in arginine catabolism, where TGF-beta may induces the arginase pathway instead of the nitric oxide pathway and a possible involvement of the vascular activation and the serum arginase in chronic hemolysis among SCA patients. Additional studies should be carried out in order to investigate the mechanisms by which TGF-beta participates in the metabolism of arginase in SCA patients.
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PMID:Arginase levels and their association with Th17-related cytokines, soluble adhesion molecules (sICAM-1 and sVCAM-1) and hemolysis markers among steady-state sickle cell anemia patients. 2040 89

Liver biopsy is the gold-standard method to stage fibrosis; however, it is an invasive procedure and is potentially dangerous. The main objective of this study was to evaluate biological markers, such as cytokines IL-13, IFN-gamma, TNF-alpha and TGF-beta, platelets, bilirubins (Bil), alanine aminotransferase (ALT) and aspartate aminotransferase (AST), total proteins, gamma-glutamil transferase (gamma-GT) and alkaline phosphatase (AP), that could be used to predict the severity of hepatic fibrosis in schistosomiasis and hepatitis C (HC) as isolated diseases or co-infections. The following patient groups were selected: HC (n = 39), HC/hepatosplenic schistosomiasis (HSS) (n = 19), HSS (n = 22) and a control group (n = 13). ANOVA and ROC curves were used for statistical analysis. P < 0.05 was considered significant. With HC patients we showed that TNF-alpha (p = 0.020) and AP (p = 0.005) could differentiate mild and severe fibrosis. With regard to necroinflammatory activity, AST (p = 0.002), gamma-GT (p = 0.034) and AP (p = 0.001) were the best markers to differentiate mild and severe activity. In HC + HSS patients, total Bil (p = 0.008) was capable of differentiating between mild and severe fibrosis. In conclusion, our study was able to suggest biological markers that are non-invasive candidates to evaluate fibrosis and necroinflammatory activity in HC and HC + HSS.
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PMID:Correlation of biological serum markers with the degree of hepatic fibrosis and necroinflammatory activity in hepatitis C and schistosomiasis patients. 2072 91


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