A comparative study of urinary xanthopterin and neopterin in liver diseases.
TL;DR: It is suggested that increased concentrations of urinary xanthopterin in liver diseases reflect not only the status of activated cell-mediated immunity, but also injury to liver cells.
Abstract: By adsorption to activated charcoal, various pteridine derivatives in human urine are oxidized to xanthopterin. Following this oxidation, xanthopterin in urine from healthy subjects and from patients with liver diseases was assayed by high performance liquid chromatography. The mean values for xanthopterin in healthy subjects were 532 +/- 116 mumol/mol creatinine (mean +/- SD) in males and 585 +/- 153 mumol/mol creatinine in females; the difference was statistically significant (p < 0.01). Xanthopterin concentrations in patients with liver disease were significantly higher than those in normal subjects. When compared with urinary neopterin, which is a marker of activated cell immunity, xanthopterin was significantly increased even in fatty liver disease. These findings suggest that increased concentrations of urinary xanthopterin in liver diseases reflect not only the status of activated cell-mediated immunity, but also injury to liver cells.
Summary (2 min read)
- Many pteridine derivatives have been found in human urine (1) .
- Among these pteridines, neopterin has been used as a biochemical marker of the activated state of cell-mediated immunity, and it has been used to monitor and screen for some clinical disorders (2 -6) .
- Some current studies show that urinary neopterin concentrations in patients with acute or chronic viral hepatitis are higher than in normal controls (7, 8) .
- An early report describes the occurrence of the compound in human urine (1) .
- In the present paper the authors assayed urinary xanthopterin in different types of liver disease.
Patients with liver disease
- Urine samples were collected from in-and out-patients in the liver unit, Tokyo National Sanatorium Hospital.
- The results of routine biochemical liver tests in each group are shown in table 1.
- Among the acute viral hepatitis cases (4 males and 4 females, mean age 37 years), 5 were type A (anti-IgM HAV antibody positive), 1 was type B (HBs antigen and anti-IgM HBc antibody positive) and 2 were type C (both above HAV and HBV markers negative and anti-clOO-3 positive).
- The nonalcoholic fatty liver cases (12 males and 1 female, mean age 43 years) were considered to be due to obesity and/or metabolic abnormalities such as hyperlipaemia or non-insulin-dependent diabetes.
- Renal failure was not present in any of the study subjects, according to urinary and serologic tests.
Urine and blood sample analysjs
- After the measurement of creatinine concentrations by the alkaline picrate method, urine samples were immediately stored at -30°C in the dark until used for the measurement of xanthopterin and neopterin.
- Blood samples were taken from all test subjects at the Tokyo National Sanatorium Hospital at the time of urine collection.
- Serum tests were performed for the following enzymes; alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase.
- As a screening test, the zinc turbidity test was also performed.
- All analyses were conducted using a 736-40E multi-channel autochemicai analyser (Hitachi Co., Ltd., Tokyo, Japan).
Urinary xanthopterin assay
- Urinary xanthopterin was measured applying the isolation method of Plesner & Kalckar (12) and using high performance liquid chromatography (HPLC) for quantitation as follows:.
- This mixture was centrifuged at 6700 g for 5 minutes and after a 10 fold dilution of the supernate with distilled water, 50 μ! of the solution was injected into the HPLC system.
- For fluorescence detection, a Jasco FP-110 spectre-photometer (Japan Spectroscopic Co., Ltd., Tokyo, Japan) was used with excitation at 390 nm and emission measurement at 460 nm.
- Peaks were recorded on a D-2000 chromato integrator (Hitachi Co., Ltd., Tokyo, Japan).
- The main peak, which showed a retention time of 10.5 minutes, was identified as xanthopterin by comparison with authentic xanthopterin using the HPLC system described above.
Urinary xanthopterin in liver disease patients
- As shown in table 3 , urinary xanthopterin concentrations in patients with liver disease including nonalcoholic fatty liver were significantly higher than those in healthy subjects.
- The highest concentrations of xanthopterin were found in the acute hepatitis patients, and xanthopterin concentrations were also high in chronic active hepatitis.
- Urinary xanthopterin concentrations in the active stages of chronic hepatitis were statistically higher than in the persistent stages (chronic active hepatitis vs. chronic persistent hepatitis: ρ < 0.01).
Comparison with urinary neopterin
- Urinary neopterin concentrations for the same subjects are also shown in table 3 .
- Neopterin was significantly elevated in cases of acute hepatitis, chronic hepatitis, liver cirrhosis and alcohol-induced liver disease, when compared with normal subjects.
- When the normal upper limit of each pteridine was set at the mean +.
- 2 SD for xanthopterin was 764 μηηοΐ/mol creatinine in males and 891 μηιοΐ/mol creatinine in females, and for neopterin it was 169 μιηοΐ/mol creatinine in males and 196 μηιοΐ/mol creatinine in females.
- There was a significant difference in xanthopterin concen-trations between chronic active hepatitis and chronic persistent hepatitis (82% and 25%, p < 0.001), while neopterin did not show this difference (79% and 70%, p > 0.05).
- In the present paper a new method of urinary xanthopterin assay after treatment with activated charcoal is presented.
- Using this method the authors assayed urinary xanthopterin in healthy individuals and in patients with liver disease.
- In their study, urinary neopterin concentrations were very high in acute hepatitis, and high in virusinduced chronic liver diseases.
- When neopterin, biopterin or dihydrobiopterin were examined by this method, no increase in urinary xanthopterin was observed.
- After treatment with activated charcoal, eluates obtained by this method were fairly pure, and an HPLC column could be used for hundreds of samples without column washing.
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