Serum bile acid concentrations as a liver function test in workers occupationally exposed to organic solvents

Abstract

Liver injury has long been associated with occupational exposure to a wide variety of chemicals. The controversial data existing in relation to hepatotoxicity of organic solvents might be explained as a consequence of the different exposures or it may well be that the tests used for evaluating liver function might not be sensitive enough to detect any mild changes at an early stage. To study liver function during exposure to solvent mixtures, we determined serum bile acid (SBA) concentrations as compared with conventional liver function tests in a selected group of workers (n = 30) occupationally exposed to a mixture of organic solvents (mostly toluene, xylene, acetone, n-butylacetate, n-butanol, ethylacetate) and in a reference group (n = 20). The mean levels of liver enzyme activities and bilirubin concentrations in the two groups were similar, whereas mean SBA levels increased in the exposed group (8.0 +/- 6.0 mumol/l vs 2.8 +/- 1.4 mumol/l) and the difference as compared with the controls was significant (P less than 0.01). In 73% of the exposed workers, SBA levels were higher than 5.6 mumol/l (the cut-off value) as compared with 5% of the controls. These results demonstrate the higher sensitivity in detecting liver dysfunction achieved with the SBA test as compared with conventional hepatic function tests. As increased SBA concentrations are considered to reflect an impairment of anion transport across the liver, higher SBA levels in the group of workers exposed to organic solvents might be explained as a slight and early sign of liver dysfunction. Therefore, SBA determination in biological monitoring of workers exposed to potentially hepatotoxic chemicals might be proposed.

Solvent exposure, alcohol consumption and liver injury in workers manufacturing paint.

“…Five biochemical variables were tested, and well over half of the worke rs (65%) had at least one variable above the local laboratory refere nce limit. Comp aring our findings with those reported for groups of other paint industry workers is problematic, as factors such as alcohol usage, obesity, exposure intensity, and reference values can vary among the groups, but it is nevertheless interesting that this group had a much greater prevalence of values outside the reference range and far higher mean enzyme activities than has been reported in other studies of paint industry workers (4)(5)(6)14). Two factors should, however, be considered when these findings are interpreted.…”

“…In contrast, Kurppa & Hu sman ( 102 ca r painte rs) (5) , Franco et al (30 workers producing fillers and varni shers ) (14 ), Hane et al (52 hou se painters) (6), and Lundberg & Hak an sson (47 paint indu stry workers) (7) all failed to show an association betw een solvents and liver injury as assess ed by routine biochem ical mea sures. Neverth eless, these negative findings should not be interpreted as an absence of an hep atotoxic effec t. Serum bile acids (14) and transferr in ( 18) may be more se nsitive measu res of possibl e hepatotoxicit y than enzy me activ ity. In addition , fatty liver disease, which may be pre sent despite normal li ver function tests, has be en lin ked to solve nt ex pos ure during hou se painting (3) and a variet y of ot he r occ upa tio ns (1 9) .…”

Toxicant-associated Steatohepatitis

“…For example, a 45.55% prevalence of liver enzyme elevation occurred in shoe repairmen exposed to toluene (Tomei et al 1999). Serum bile acids have been proposed as an alternate biomarker for solvent hepatotoxicity and were elevated in toluene- and xylene-exposed workers (Franco et al 1986) as well as workers exposed to styrene when processing sewage pipes (Edling and Tagesson 1984). An increase in γ-glutamyltransferase was associated with exposure to a mixture of 6 VOCs including benzene, toluene, and xylene (Liu et al 2009) in the National Health and Nutrition Examination Survey (NHANES).…”

Liver function alterations in synthetic leather workers exposed to dimethylformamide

“…Using this technique, we found a group of workers with abnormal paired enzymes, 11 of them with higher BA levels. In fact, BA levels might be a better indicator for occupational liver disease: the test is more sensitive (94%) and specific (78%) than transaminases [Franco et al, 1986;Tamburro and Liss, 1986]. In view of this, we found 14 more subjects with abnormal BA who could be considered as having early liver injury.…”