Plasma Cysteine and Sulphate Levels in Patients with Cirrhosis of the Liver

Abstract

1. Fasting levels of plasma cysteine, plasma sulphate and the plasma cysteine/sulphate ratio were measured in patients with primary biliary cirrhosis and compared with those in patients with other liver disease, general intensive therapy unit patients and healthy subjects. 2. Plasma cysteine was significantly elevated in patients with primary biliary cirrhosis (median 0.364 nmol/mg of protein, P < 0.0001) and patients with other liver disease (median 0.445 nmol/mg of protein, P < 0.0001), compared with healthy control subjects (median 0.125 nmol/mg of protein) and increased progressively with the severity of liver disease. Plasma cysteine was also elevated in intensive therapy unit patients (median 1.564 nmol/mg of protein) compared with healthy control subjects (P < 0.0001) and patients with other liver disease (P < 0.0001). 3. Plasma sulphate was reduced significantly only in patients with primary biliary cirrhosis (median 0.822 nmol/mg of protein) compared with healthy control subjects (median 1.37 nmol/mg of protein, P < 0.05). There was no significant difference in plasma sulphate between disease groups. 4. The plasma cysteine/sulphate ratio was significantly elevated in patients with primary biliary cirrhosis (median 0.448, P < 0.0001) and patients with other liver diseases (median 0.394, P < 0.0001) compared with healthy control subjects (median 0.095). The ratio was also elevated in intensive therapy unit patients (median 1.650, P < 0.0001) compared with healthy control subjects and liver disease groups (P < 0.0001). 5. In conclusion, cysteine rises in primary biliary cirrhosis and other forms of liver disease. This effect is not specific to liver disease, since cysteine is elevated in an heterogeneous group receiving intense care.(ABSTRACT TRUNCATED AT 250 WORDS)

Homocysteine and thiol metabolites in vitamin B12 deficiency

“…Folic acid has been suggested to increase trans-sulphuration by an unknown mechanism [20]. Secondly, a change in the disposal of cysteine through alternative pathways, protein and peptide synthesis and provision of intracellular organic sulphate was a possibility [14]. However, no change in circulating DHEAS levels was seen in the present study, providing no support for an alteration in sulphation status (a surrogate marker of altered cysteine disposal).…”

A Comparison of Anthropometry, Biochemical Variables and Plasma Amino Acids among Centenarians, Elderly and Young Subjects

“…As discussed above, clear changes of individual amino acids Amino Acids of Centenarians by aging were decreases of BCAA and methionine and increases of proline and cystine (pϽ0.05), which were similar to those found in the amino acid profiles in liver deterioration [18,19,21,37,38,40,42]. However, the GOT and GPT concentrations of our centenarian subjects were within the reference range.…”

“…The decreased concentration of methionine occurs in cirrhosis [21]. Plasma cystine was significantly elevated in patients with primary biliary cirrhosis and patients with other liver disease [42]. This may again indicate the decreased liver function in the centenarians.…”

Homocysteine and thiol metabolites in vitamin B12 deficiency

“…Secondly, a change in the disposal of cysteine through alternative pathways, protein and peptide synthesis and provision of intracellular organic sulphate was a possibility [14]. Rather, plasma cysteine levels were relatively lower before treatment and increased after vitamin B "# repletion, in a reciprocal molar manner with homocysteine.…”

“…As hyperhomocysteinaemia has been shown to injure endothelial cells via the generation of hydrogen peroxide [12] and to decrease the activity of cellular GPx [13], we wished to study the effects of the hyperhomocysteinaemia of vitamin B "# deficiency on plasma GPx. Trans-sulphuration of homocysteine also generates cysteine, which is crucial for the eventual sulphation of endogenous and exogenous substances that is necessary for elimination from the body of endogenous as well as xenobiotic molecules [14].…”