Analysis of theaflavins in biological fluids using liquid chromatography-electrospray mass spectrometry.

A HPLC-MS procedure for the sensitive and specific analysis of the black tea flavonoid theaflavin in human plasma and urine was developed. Levels were measured after enzymatic deconjugation, extraction into ethyl acetate, and separation by HPLC, using tandem mass spectrometry as a detecting system. Two healthy volunteers consumed 700 mg theaflavins, equivalent to about 30 cups of black tea. The maximum concentration detected in blood plasma was 1.0 microg l(-1) in a sample collected after 2 h. The concentration in urine also peaked after 2 h at 4.2 microg l(-1). Hence, only minute amounts of theaflavins can be detected in plasma and urine samples of healthy volunteers after ingestion.

Oxidized and free whole blood thiols in preeclampsia.

OBJECTIVE: To measure levels of oxidized and free thiols in whole blood of normotensive pregnant and preeclamptic women and evaluate the role of oxidative stress. METHODS: We measured whole blood oxidized and free levels of cysteine, homocysteine, cysteinylglycine, and glutathione by high performance liquid chromatography in women with normotensive pregnancies (n = 50), preeclampsia (n = 29), and preeclampsia complicated by the hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome (n = 16). RESULTS: Oxidized and free levels (median [range], micromol/L) of cysteine and homocysteine were higher in women with preeclampsia than normotensive pregnancies (45 [27-81] versus 29 [9-91], P <.001, and 98 [57-193] versus 69 [33-215], P <.001; 0.8 [0.2-4.4] versus 0.4 [0.01-1.6], P <.001, and 2.1 [0.7-9.4] versus 1.2 [0.2-21.2], P <.01; respectively). The ratios of free to oxidized cysteine, homocysteine, and cysteinylglycine were lower in preeclampsia than normotensive pregnancy (2.2 [1.3-3.0] versus 2.4 [1.7-4.3], P <.001; 2.3 [0.5-5.4] versus 2.9 [1.1-24], P <.001; 4.1 [2.3-11.6] versus 5.4 [2.6-24.3], P <.02, respectively), indicating a shift in favor of the oxidized form of those thiols. In HELLP syndrome, levels of oxidized and free cysteine and levels of oxidized homocysteine were higher than normal (44 [33-63] versus 29 [9-91], P <.001, and 102 [82-133] versus 69 [33-215], P <.001; 1.0 [0.3-2.9] versus 0.4 [0.01-1.6], P <.001, respectively). No significant differences were found in oxidized glutathione levels in women with preeclampsia (22 [5-49] versus 17 [2- 60], P =.06) or free levels in preeclamptic women with HELLP syndrome (757 [624-993] versus 842 [539-1516], P =.09) as compared with normotensive pregnant women. The ratios of free to oxidized cysteinylglycine and glutathione were higher in women with HELLP syndrome than in those with preeclampsia (5.4 [3.3-12.7] versus 4.1 [2.3-11.6], P =.02, and 56 [28-124] versus 45 [16-166], P =.02, respectively). CONCLUSION: Significantly lower ratios of free to oxidized cysteine, homocysteine, and cysteinylglycine in preeclampsia might indicate oxidative stress.

Plasma concentrations of individual tea catechins after a single oral dose in humans.

1. Ten healthy volunteers ingested 1.5 mmole epicatechin gallate (ECg), epigallocatechin (EGC) or epigallocatechin gallate (EGCg) in a randomized crossover design. After deconjugation, catechins in plasma and 24-h urine samples were determined by high-performance liquid chromatography (HPLC). Antioxidant activity was measured in plasma by determining ferric reducing activity (FRAP). 2. The catechin levels in plasma after ingestion were significantly different: EGC rose quickly with a short elimination half-life (t1/2 elim = 1.7 h), ECg was intermediate in rise but slowest in decline (t1/2 elim = 6.9h), EGCg was slowest in rise but intermediate in decline (t1/2 elim = 3.9h). At 24h, EGC and EGCg had returned to base levels, but ECg was still elevated. Peak maximum varied between 1.3 (EGCg) and 5.0 micromol l(-1) (EGC). 3. Very limited interconversion (ECg-->epicatechin, EGCg-->EGC) occurred indicating that degallation is not required for uptake. 4. Up to 13.6% of the ingested EGC (partly methylated) was excreted in the urine, but ECg or EGCg were not detected. 5. EGC and ECg produced an increase in antioxidant activity in plasma, but with EGCg, no statistically significant effect was found. 6. The pattern of uric acid in plasma showed a clear resemblance with that of FRAP and linear regression analysis indicated a very significant relationship (R2 = 0.88, p < 0.0001). 7. It is concluded that tea catechins differ significantly in their pharmacokinetic behaviour.

Plasma glutathione S-transferase pi 1-1 AND alpha 1-1 levels in patients with bladder cancer.

PURPOSE: Transitional cell carcinomas of the human bladder and many gastrointestinal tumors often contain high amounts of the detoxification enzyme glutathione S-transferase pi (GSTP1-1). Elevated levels of GSTP1-1 have been found in serum and plasma from patients with gastrointestinal, lung or head and neck cancer. GSTP1-1 and glutathione S-transferase alpha (GSTA1-1) have been reported to be increased in 10 of 15 patients (67%) with bladder cancer. We evaluate the role of GSTP1-1 and GSTA1-1 as plasma tumor markers in 50 patients with bladder cancer before and after treatment. MATERIALS AND METHODS: Blood from patients with bladder cancer was sampled in ethylenediaminetetraacetic acid tubes. Plasma GSTA1-1 and GSTP1-1 were measured using the sensitive and specific sandwich enzyme-linked immunosorbent assay. RESULTS: Respective plasma GSTA1-1 and GSTP1-1 levels were above the upper normal reference limit in 2 (4%) and 14 (28%) of the 50 patients with bladder cancer. No significant decrease in plasma GSTA1-1 or GSTP1-1 was noted in matched pairs of plasma samples collected before and after treatment. CONCLUSIONS: In contrast to earlier reports, only a limited number of patients with bladder cancer had increased plasma GSTA1-1 or GSTP1-1, which did not decrease after tumor resection. These findings argue against the use of GSTP1-1 or GSTA1-1 as plasma markers for bladder cancer.

Urinary excretion of glutathione S transferases alpha and pi in patients with proteinuria: reflection of the site of tubular injury.

In patients with renal diseases, proteinuria is a major determinant of progressive renal failure, probably by causing tubular cell injury. Little is known on extent and site of tubular cell injury in patients with proteinuria. Glutathione S transferases (GST) are cytosolic enzymes. The alpha isoform is present only in proximal tubular cells, whereas the pi isoform is confined to distal tubular cells. We have studied the urinary excretion of both isoenzymes in 56 (38 male and 18 female) patients with glomerular diseases and proteinuria. The mean age was 45 +/- (SD) 16 years, the median creatinine clearance was 80 (range 27-159) ml/min, and the median albuminuria was 4.2 (range 0.7-16.9) g/10 mmol creatinine. The excretions of both GST alpha (median 35.9 ng/10 mmol creatinine) and GST pi (median 24.8 ng/10 mmol creatinine) were elevated as compared with control values (upper limits 10 and 12 ng/10 mmol creatinine, respectively). The urinary excretion of GST pi, but not that of GST alpha, was inversely correlated with the creatinine clearance. The highest levels of GST alpha were found in patients with a well-preserved renal function, whereas highest levels of GST pi were found in patients with renal failure. In a small number of patients we performed immunofluorescent studies of renal tissue. An increased urinary excretion of GST alpha correlated with brush border damage and decreased staining of proximal tubules for that isoenzyme. Our data suggest that in patients with proteinuria initial injury is apparent at the proximal tubules. Measurements of GST alpha and GST pi appear useful to study longitudinal timing and site of proteinuria-induced tubular cell injury.

Plasma protein carbonyls in nonpregnant, healthy pregnant and preeclamptic women.

Increased reactive oxygen species (ROS) and lipid peroxidation may be implicated in the pathogenesis of preeclampsia by causing cell (membrane) damage and impaired endothelial function. Carbonyl derivatives of proteins, or protein carbonyls, may be sensitive biomarkers of ROS-mediated damage. The aim of the study was to compare levels of protein carbonyls in plasma of preeclamptic, healthy pregnant and healthy nonpregnant women. Plasma protein carbonyls were measured in 47 preeclamptic, 45 healthy pregnant and 22 healthy nonpregnant women by using a sensitive ELISA-method. ANOVA, the unpaired t-test and Pearson's correlation were used for statistical analysis. Preeclamptic women had significantly higher plasma protein carbonyl levels than healthy pregnant women (P < 0.0001). Healthy pregnant women showed significantly higher protein carbonyl levels (P < 0.001) as compared to nonpregnant controls. The higher levels of protein carbonyls as compared to nonpregnant controls suggest that increased oxygen free radical damage occurs in normal pregnancy and to a much higher extent in preeclampsia.

Plasma glutathione S-transferase Pi 1-1 measurements in the study of hemolysis in hypertensive disorders of pregnancy.

OBJECTIVE: To investigate the value of plasma glutathione S-transferase Pi1-1(GSTP1-1) measurements in the assessment of hemolysis in hypertensive disorders of pregnancy. METHODS: Plasma GSTP1-1 and haptoglobin levels and serum lactate dehydrogenase (LDH) activity were measured in 81 healthy nonpregnant female blood donors between 20 and 40 years of age, 41 women during uncomplicated normotensive pregnancy, 35 women with pregnancy-induced hypertension, 67 women with preeclampsia, and 34 women with the HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome. Levels in hypertensive pregnancies were compared to levels in normotensive pregnancy, and levels in normotensive pregnancy were compared to levels in blood donors by the Mann-Whitney U-test. RESULTS: Median GSTP1-1 and LDH levels were significantly increased (p < 0.01) and haptoglobin significantly decreased (p < 0.01) in preeclampsia and the HELLP syndrome as compared to normotensive pregnancy. Both GSTP1-1 and LDH levels were significantly higher in normotensive pregnant women as compared to nonpregnant women (p < 0.0001). The percentage of preeclamptic patients (26.9%) or patients with the HELLP syndrome (73.5%) with elevated GSTP1-1 levels was lower than those with elevated LDH (38.8% and 100%, respectively) or decreased haptoglobin levels (41.8% and 97%, respectively). CONCLUSIONS: We conclude that plasma GSTP1-1 levels may provide useful information on hemolysis in hypertensive disorders of pregnancy in addition to serum LDH activity and plasma haptoglobin levels and that the degree of hemolysis in hypertensive disorders of pregnancy, especially in the HELLP syndrome, is probably less prominent than generally assumed.

Glutathione and glutathione-related enzymes in decidua and placenta of controls and women with pre-eclampsia.

Pre-eclampsia is a major complication of pregnancy with high morbidity and mortality rates. The aetiology is still unclear but impaired detoxification or enhanced levels of reactive (oxygen) metabolites may contribute to the development or maintenance of pre-eclampsia. Glutathione and glutathione-related enzymes, as one of the major detoxificating and free-radical scavenging systems, may play a role in controlling the disease. Seventeen normotensive pregnant women and 24 pre-eclamptic women were investigated prospectively with respect to placental and decidual levels of total glutathione (GSH), glutathione S-transferase activity (GST), selenium-dependent glutathione peroxidase (SeGPX) and total glutathione peroxidase activity (TGPX, both selenium- and non-selenium-dependent GPX). Decidual levels of glutathione and related enzymes were compared with placental levels, and the investigated parameters in pre-eclampsia were compared with those in normotensive pregnancy by the Mann-Whitney U -test. Clinical data were correlated with biochemical parameters by Spearman's correlation test. Glutathione levels were significantly higher in decidua as compared with placenta. Glutathione levels were elevated in pre-eclampsia and HELLP (haemolysis, elevated liver enzymes, low platelets) as compared to normotensive pregnancy for decidua and in the placenta of patients with pre-eclampsia only. Glutathione S-transferase activity was not different between the two groups. In the placenta of patients with pre-eclampsia+HELLP, total glutathione peroxidase activity was elevated versus controls. Selenium-dependent glutathione peroxidase activity was higher in decidua versus placenta and in decidua of pre-eclamptic versus control subjects. Enhanced glutathione concentrations and glutathione peroxidase activities were often found in placenta and decidua in pre-eclampsia, probably as a compensatory mechanism to prevent further damage by peroxides, (oxygen) radicals or other toxins in the placenta or in the feto-placental interface.

Variability of glutathione S-transferase alpha in human liver and plasma.

BACKGROUND: Glutathione S-transferases are a family of enzymes involved in the binding, transport, and detoxification of a wide variety of endogenous and exogenous compounds. Little information is available about the variability of class alpha glutathione S-transferases in human liver, where they are highly expressed, or in serum. METHODS: Both total class alpha glutathione S-transferase (GST-alpha, composed of GSTA1-1, GSTA1-2, and GSTA2-2) as well as GSTA1-1 concentrations were measured by specific and sensitive ELISA in liver cytosols of 35 organ donors and in plasma samples of 350 healthy controls. RESULTS: The mean total GST-alpha and GSTA1-1 in liver cytosols were 25.1 +/- 9.4 and 10.7 +/- 5.3 microg/mg protein, respectively, and did not correlate with activities of aspartate aminotransferase or alanine aminotransferase. The mean total GST-alpha in liver was significantly higher in females compared with males (28.8 +/- 10.0 vs 22.0 +/- 7.8 microg/mg protein; P <0.05). In contrast, the median total GST-alpha in plasma was lower in females compared with males (2.0 and 2.8 microg/L, respectively; P <0.0001). The median ratios for GSTA1-1/total GST-alpha in liver and plasma were 0.42 and 0.58, respectively. CONCLUSIONS: GSTA1-1 constitutes approximately one-half of the total amount of alpha class GSTs in human plasma and liver. Total GST-alpha values are higher in female liver but lower in plasma compared with the respective values in males.

Low whole blood glutathione levels in pregnancies complicated by preeclampsia or the hemolysis, elevated liver enzymes, low platelets syndrome.

OBJECTIVE: To investigate the pathophysiologic involvement of glutathione in pregnancies complicated by preeclampsia or the hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome. METHODS: Total whole blood glutathione levels were measured by high performance liquid chromatography in 23 women with pregnancies complicated by preeclampsia or the HELLP syndrome and in 22 normotensive gravidas. Total glutathione levels and the total glutathione/hemoglobin ratios of patients were compared with those of controls by the Mann-Whitney U test. RESULTS: Median total glutathione levels were lower in preeclamptic pregnancies or those complicated by the HELLP syndrome than in normotensive pregnancies (647 [range 268-986] and 750 [range 495-1572] micromol/L, P = .05). The median total glutathione/hemoglobin ratios were significantly lower in preeclamptic pregnancies or in those complicated by the HELLP syndrome than in normotensive pregnancies (0.079 [range 0.033-0.122] and 0.101 [range 0.073-0.210], P = .02). CONCLUSION: Decreased total glutathione levels in maternal whole blood might indicate decreased detoxificating or free radical scavenging capacity in pregnancies complicated by preeclampsia or the HELLP syndrome.

Plasma glutathione S-transferase P1-1 levels in patients with head and neck squamous cell carcinoma.

BACKGROUND: Many tumors contain high amounts of the detoxification enzyme glutathione S-transferase P1-1 (GSTP1-1). Elevated levels of GSTP1-1 have also been detected in serum and plasma from patients with gastrointestinal, lung, or head and neck tumors. The authors of this report evaluated the role of GSTP1-1 as a plasma tumor marker in patients with head and neck squamous cell carcinoma (HNSCC) of the larynx, hypopharynx, or oropharnyx and in patients with benign head and neck lesions (BHNL). METHODS: GSTP1-1 levels were measured in EDTA plasma combined with ethylenediaminetetraacetic acid using a recently developed sensitive and specific sandwich enzyme-linked immunoadsorbent assay. A normal reference level with an upper limit of 21.8 microg GSTP1-1 per liter of plasma was calculated from results obtained with samples from 230 blood donors. RESULTS: Median GSTP1-1 levels in samples from 53 patients with oral/oropharyngeal SCC (10.6 microg/L; range, 3.7-46.1 microg/L), 12 patients with hypopharyngeal SCC (11.9 microg/L; range, 5.2-146.6 microg/L), and 28 patients with laryngeal SCC (14.4 microg/L; range, 6.4-141.5 microg/L) were significantly elevated when compared with plasma GSTP1-1 levels in samples from 45 patients with BHNL (8.1 microg/L; range, 3.3-32.3 microg/L; P < 0.0001, P < 0.01, and P < 0.0001, respectively). However, only 6 of 53 patients (11%) with oral/oropharyngeal SCC, 1 of 12 patients (8%) with hypopharyngeal SCC, and 6 of 28 patients (21%) with laryngeal SCC had plasma GSTP1-1 levels above the upper limit of the normal reference level. Thus, only 13 of 93 patients (14%) with HNSCC had elevated plasma GSTP1-1 levels overall. No significant relation between plasma GSTP1-1 levels and TNM classification of the tumors was observed. CONCLUSIONS: GSTP1-1 is not a suitable plasma tumor marker for HNSCC.

Umbilical cord plasma glutathione S-transferase alpha 1-1 levels as a marker of neonatal hepatocellular integrity.

OBJECTIVE: To investigate possible delivery-related impaired neonatal hepatocellular integrity by assessment of arterial and venous umbilical cord plasma levels of glutathione S-transferase Alpha 1-1. METHODS: Glutathione S-transferase Alpha 1-1 levels were assessed in arterial and venous umbilical cord, and maternal venous plasma samples. The influence of maternal, delivery, and neonatal characteristics on arterial umbilical cord glutathione S-transferase Alpha 1-1 levels was studied, using linear regression analysis after log-transformation. RESULTS: Median (range) arterial umbilical cord glutathione S-transferase Alpha 1-1 plasma levels were higher than venous umbilical cord levels (9.68 [0.64-1125] microg/L and 7.66 [0.78-987.5] microg/L, respectively, P < .005). Median (range) arterial and venous umbilical cord glutathione S-transferase Alpha 1-1 levels were higher than, and did not correlate with, maternal venous plasma levels (8.79 [1.79-183] microg/L and 6.47 [1.58-164.5] microg/L versus 1.47 [0.46-10.4] microg/L, P < .001). Neonates born vaginally demonstrated higher median (range) levels than those delivered by cesarean (13.41 [1.02-1125] microg/L and 5.73 [0.64-172.90] microg/L, respectively, P < .001). Neonates with unfavorable pH (arterial pH under 7.20) demonstrated higher median (range) levels than those with normal pH (arterial pH at least 7.20) (15.15 [0.77-1125] microg/L and 8.82 [0.64-120.90] microg/L, respectively, P < .001). Stepwise multiple linear regression analysis showed that birth weight had the largest influence on arterial umbilical cord glutathione S-transferase Alpha 1-1 levels, followed by arterial base deficit, and route of delivery. CONCLUSION: Arterial umbilical cord glutathione S-transferase Alpha 1-1 plasma levels, being unrelated to maternal venous levels, might give a reliable impression of early neonatal hepatocellular integrity and may become an additional indicator of neonatal condition immediately after birth.

Plasma glutathione S-transferase alpha 1-1: a more sensitive marker for hepatocellular damage than serum alanine aminotransferase in hypertensive disorders of pregnancy.

OBJECTIVE: Our purpose was to investigate the value of plasma glutathione S-transferase Alpha 1-1 measurements in the assessment of hepatocellular damage in hypertensive disorders of pregnancy. STUDY DESIGN: Patients were recruited at the Department of Obstetrics and Gynecology of the University Hospital, Nijmegen, The Netherlands. Five groups of patients were studied: normotensive pregnancy (n = 87), pregnancy-induced hypertension (n = 48), preeclampsia (n = 79), the syndrome of hemolysis, elevated liver enzymes, and low platelets (n = 39), and serially studied normotensive pregnancy (n = 21). Blood was collected for assessment of plasma glutathione S-transferase Alpha 1-1 levels and serum alanine aminotransferase activity. Levels in hypertensive pregnancies were compared with levels in normotensive pregnancy by the Mann-Whitney U test. Patients were categorized according as to whether their values are below (normal) or above (elevated) the upper normal reference level. The difference in relative magnitude of elevation between the two factors was determined by the Wilcoxon matched-pairs signed-rank test. RESULTS: Plasma levels in the longitudinally studied normotensive pregnancy group did not differ between gestational ages and were not significantly different from those of the normotensive control group. Median levels of glutathione S-transferase Alpha 1-1 and alanine aminotransferase were significantly increased (p < 0.01, p < 0.0001, respectively) in all subgroups of hypertensive pregnancies compared with normotensive pregnancies. When both levels were elevated, the relative magnitude of the increase of glutathione S-transferase Alpha 1-1 levels was significantly higher than that of alanine aminotransferase activity in preeclampsia (p < 0.01) and the syndrome of hemolysis, elevated liver enzymes, and low platelets (p < 0.0001). Almost half the patients with preeclampsia showed elevated levels of alanine aminotransferase and/or glutathione S-transferase Alpha 1-1. CONCLUSION: Plasma glutathione S-transferase Alpha 1-1 measurements may provide a more sensitive indicator of acute hepatic damage in preeclampsia and the syndrome of hemolysis, elevated liver enzymes, and low platelets compared with the assessment of aminotransferase activity and therefore may allow earlier recognition of these syndromes. The clinical benefits of plasma measurements of glutathione S-transferase Alpha 1-1 for monitoring the hepatic condition in the management of these patients need to be elucidated in further studies.

Glutathione S-transferases in human ovarian follicular fluid.

OBJECTIVE: To study the levels of glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 in human preovulatory ovarian follicular fluid (FF) and pooled granulosa and cumulus cells. DESIGN: The relation of glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 with P and 17 beta-E2 concentrations were studied. SETTING: The Department of Obstetrics and Gynecology, the Department of Gastroenterology, and the Laboratory of Endocrinology and Reproduction of the University Hospital Nijmegen in Nijmegen, the Netherlands. PATIENT(S): Infertile women participating in an IVF program. RESULT(S): Detectable amounts of glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 were found in ovarian FF and pooled cumulus and granulosa cells. Concentrations of glutathione S-transferase Alpha 1-1 were always much higher than those of glutathione S-transferase Pi 1-1. Both ovarian FF concentrations of glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 did not correlate with ovarian FF concentrations of 17 beta-E2 and P. CONCLUSION(S): The high FF concentrations of glutathione S-transferase Pi 1-1 and especially of glutathione S-transferase Alpha 1-1 suggest that these enzymes may play an important role in the detoxification processes in the follicles. The lack of correlation between follicular P and 17 beta-E2 and glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 indicates that both enzymes presumably are not present as a result of the high steroid levels.

Measurement of glutathione S-transferase P1-1 in plasma: pitfalls and significance of screening and follow-up of patients with gastrointestinal carcinoma.

BACKGROUND: Gastrointestinal tumors often contain high amounts of the detoxification enzyme glutathione S-transferase P1-1 (GSTP1-1). Elevated levels of GSTP1-1 were found in serum and plasma from most patients with gastrointestinal tumors. The authors evaluated the role of GSTP1-1 as a plasma tumor marker in patients with gastrointestinal tumors. METHODS: A sensitive and specific sandwich enzyme-linked immunoadsorbent assay for quantification of GSTP1-1 in human plasma was developed. RESULTS: GSTP1-1 levels in serum samples from 10 healthy controls were significantly (P < 0.0001) higher than in corresponding ethylenediaminetetraacetic acid (EDTA) plasma and varied with the type of blood collection tube used. Refrigeration or delayed centrifugation of blood collected in plain EDTA tubes resulted in spuriously high plasma GSTP1-1 levels. Therefore, all plasma samples were collected in silicone-coated EDTA tubes. The distribution of plasma GSTP1-1 levels in 230 blood donors was nearly normalized by logarithmic transformation and an upper normal reference level of 21.8 microg/L was calculated. Males had significantly higher (P < 0.0001) plasma GSTP1-1 levels than females and a significant increase (P < 0.004) in plasma GSTP1-1 with age was noted. In only 20 of 55 patients (36%) with gastrointestinal tumors was the plasma GSTP1-1 level above the upper normal reference limit. No significant decrease in plasma GSTP1-1 was noted in matched pairs of plasma samples collected from 17 patients before and at least 2 weeks after resection of the tumor. CONCLUSIONS: The GSTP1-1 level in serum and plasma depends on the materials and methods used to collect the samples. Only 36% of the patients with gastrointestinal tumors had elevated plasma GSTP1-1 levels that did not decrease after resection of the tumor. These findings argue against the use of GSTP1-1 as a serum or plasma marker for gastrointestinal tumors.

Plasma glutathione S-transferase alpha 1-1 levels in patients with chronic liver disorders.

Recent data suggest that plasma levels of the phase II detoxification enzyme glutathione S-transferase alpha may be a sensitive indicator of hepatocellular integrity in acute liver disorders but little information is available in chronic hepatic disorders. Using a newly developed enzyme linked immunosorbent assay, glutathione S-transferase A1-1 (GSTA1-1) levels were measured in 279 plasma samples from patients with chronic liver disorders. Results were categorized as normal or elevated plasma GSTA1-1 and normal or elevated plasma aspartate aminotransferase (AST) levels. In 24 patients with alcoholic liver cirrhosis, plasma GSTA1-1 levels were not significantly different from a group of 350 healthy controls and only one patient (4%) had an elevated GSTA1-1 level while 10 (42%) patients had elevated AST activities. In samples from patients with primary biliary cirrhosis (n = 150), primary sclerosing cholangitis (n = 26) or chronic hepatitis (n = 79) significantly (P < 0.0001) elevated plasma GSTA1-1 concentrations were detected in 25 (17%), 7 (27%) and 17 (22%) of the samples, respectively. AST activities were increased in a higher percentage of samples in all three disorders: 89%, 88%, and 57%, respectively. Plasma GSTA1-1 and AST levels were significantly correlated (P < 0.005) in the above mentioned disorders but not in alcoholic liver cirrhosis. It is concluded that plasma GSTA1-1 is not a sensitive parameter for the detection of hepatocellular damage in chronic liver disorders.

Sandwich ELISA for glutathione S-transferase Alpha 1-1: plasma concentrations in controls and in patients with gastrointestinal disorders.

Class Alpha glutathione S-transferases (GST-Alpha) are found in high concentrations in human liver. Increased plasma concentrations of GSTA1-1, the most abundant isoform of GST-Alpha, are a very sensitive marker for hepatocellular leakage. A sandwich-type ELISA was developed, based on a monoclonal antibody specific for human GSTA1-1 and a polyclonal rabbit anti-human GST-Alpha antiserum. The assay is specific for human GSTA1-1, and has a detection limit of 0.04 micrograms/L. The distribution of plasma GSTA1-1 concentrations in 350 blood donors was nearly normalized by logarithmic transformation and an upper normal reference concentration of 5.9 micrograms/L was calculated. Men had significantly higher plasma GSTA1-1 concentrations than women (P <0.0001). In women, but not in men, a significant increase was noted with age (P <0.05). In patients with inflammatory bowel disease (n= 210), gastrointestinal tumors (n= 70), irritable bowel disease (n= 36), or chronic pancreatitis (n= 12), plasma GSTA1-1 concentrations were similar to those of controls. In contrast, plasma GSTA1-1 concentrations were increased to a similar extent as alanine aminotransferase activities in patients with liver disorders (n= 37).

Glutathione S-transferase pi in colorectal tumors is predictive for overall survival.

Glutathione S-transferases (GSTs) are enzymes involved in the detoxification of xenobiotics and are divided into four subclasses, alpha, mu, pi, and theta, with different although overlapping substrate specificities. Most human gastrointestinal tumors contain increased amounts of GST-pi and GST enzyme activity. The relationship between GST parameters and tumor and patient characteristics, including overall survival, were studied retrospectively in 100 primary colorectal adenocarcinomas. Levels of GST-alpha, GST-mu, GST-pi, and GST enzyme activity were not related to the Dukes stage, differentiation grade, localization, histological type and diameter of the tumor, or gender and age of the patient. Fifty-seven patients died (median survival, 21 months; range, 1-65 months) during follow-up, and 43 patients were still alive at the closing date of the study (median follow-up, 68 months; range, 60-87 months). Optimal dichotomization and uni- and multivariate analyses were done with the Cox proportional hazard model. Multivariate analysis with all clinicopathological parameters revealed higher Dukes stage (hazard ratio, 2.7; P < 0.001) and older age (hazard ratio, 2.8; P = 0.001) to be the only independent prognostic variables for overall survival. In contrast to GST-alpha and GST-mu, high levels of GST-pi (hazard ratio, 3.1; P = 0.002) and GST enzyme activity (hazard ratio, 2.0; P = 0.020) in the tumors were found to have a significant prognostic value independent from the clinicopathological parameters when added separately to this Cox model. Thus, this study indicates that GST subclass levels in colorectal adenocarcinomas are not related to clinicopathological parameters and that the GST-pi level and GST enzyme activity have a prognostic value for the overall survival of the patients.