Serum lactate dehydrogenase and its isoenzyme pattern in ex-coalminers

Abstract

Serum lactate dehydrogenase (LDH) activity, a marker of cell damage, is increased in several pulmonary disorders, especially when fibrosis is involved. In rats exposed to silica, high levels of LDH activity were found. A rise of serum LDH3 has been associated with lung tissue injury. The aim of this study was to investigate the serum LDH isoenzyme pattern after coal-dust exposure and the possible relation to pulmonary function tests. Ex-coalminers (n = 201), with a history of coal-dust exposure more than 20 yr ago, were admitted to the authors' hospital for a medical check-up and were included in the study. The serum LDH activity was found to be elevated in 79.1% of the ex-coalminers (634 +/- 245 U I-1). Moreover, in 196 of the 201 cases (97.5%), a high LDH3 level (31 +/- 4%) was demonstrated. A moderate negative relation was found between the forced expiratory volume in 1 s (FEV1) and the LDH activity (r = -0.26; P < 0.001), as well as between FEV1 and LDH3 activity (r = -0.23; P < 0.001), even in the subgroup (n = 42) with a normal LDH. All other liver function tests were within normal limits. These results suggest that coal-dust, even many years after the actual exposure, causes an increase in the total serum LDH activity and changes in the LDH-isoenzyme pattern, mainly characterized by a high LDH3 activity.

Lactate dehydrogenase as a biomarker for silica exposure-induced toxicity in agate workers

“…High LDH levels in plasma samples of the exposed subjects in this study are similar to the previous studies of LDH activity in the serum of ex coal miners8 and patients with silicosis 29. The agate workers in this study were exposed to 15 times higher than permissible levels of silica dust,14 15 for 6–8 h every day for an average of 16±8 years.…”

“…One study has shown increased LDH activity in the lung lavage (BAL) of Québec granite workers 28. In another study of serum samples from exposed subjects, Cobben et al 8 reported a significant increase (about four times) in LDH activity in ex coal miners. and a recent study by Deniz et al 29 suggested significantly high serum LDH levels in patients with silicosis.…”

“…The cells were lysed using the lysis buffer (10 mM Tris base, 10 mM KCl, 10 mM MgCl 2 , pH-7.6), and the cell lysates were cleared of any cell debris by centrifugation at 12 000 rpm for 15 min. LDH activity was measured in the blood plasma and cell lysates at room temperature using sodium pyruvate as a substrate 8. In brief, 10 µL of blood plasma or 10 µL of cell lysate was incubated with 3.0 mL of assay substrate (0.2 M Tris HCl, 6.6 mM NADH, 30 mM sodium pyruvate) for 10 min.…”

“…Hayashi et al 7 showed that 24 h of silica exposure in rats could induce a 10-fold increase of LDH in blood serum. A study in ex-coal miners suggests that coal dust exposure increases LDH activity in serum even after stoppage of exposure of coal dust 8. Most of the previous LDH studies in vivo,6–7 9–11 suggested increases of LDH activity in serum and BAL fluid of silica-exposed animals.…”

Serum biomarkers in interstitial lung diseases

“…CC16 [85], antioxidants [79] and several cytokines [80] has been raised many times. Towards this direction Cobben et al [86] studied the role of LDH (a marker of cell damage) as marker of lung tissue injury. Authors conducted the first human study describing a considerable elevation of this enzyme in a group of ex-coalminers and a further association with other clinical variables.…”