#0122 Indium concentration in serum is an excellent predictor for assessing accumulated indium concentration in the lungs

It Runs in the Blood: Serum Indium Levels Are Related to Those in the Lungs

In 2001, a worker who was regularly exposed to fine indium-containing dusts died of lung collapse (pneumothorax) and scarring (interstitial pneumonia). Since then, many studies have been conducted to determine if exposure to hardly soluble indium dusts can cause respiratory diseases.

In previous epidemiological works, we successfully demonstrated the casual relationship between indium dust and lung diseases. However, we used the indium levels in blood serum as an indicator of exposure to indium because there are no easy ways to measure the levels of indium accumulated in lung tissue. The question of whether indium levels in serum can accurately represent indium levels in the lungs remained unanswered—until now.

We sought to answer this question in our latest study using data from our 15-year cohort follow-up of workers in 11 factories that handle indium. Five indium-exposed male workers that were enlisted in this follow-up underwent surgery of the lungs for different diseases, including lung cancer and recurrent pneumothorax. With consent from all participants, we took these surgeries as opportunities to check if a clear relationship exists between indium levels in serum and in extracted lung tissue. After analyzing the blood serum and lung tissue samples, we found a remarkably good correlation between the indium levels in both. It appears indium levels in the lungs tend to be several thousand times higher than in blood.

Overall, our study showcases how measuring indium levels in blood serum, which is a rather easy and minimally invasive procedure, could be a reliable way to indirectly assess the amount of indium accumulated in the lungs. However, considering we only included five cases, further studies should be conducted to confirm our conclusions. Finding simple and better ways to measure exposure to indium dusts will allow doctors and researchers to better understand how such chemicals adversely affect our bodies. Hopefully, it will ultimately help create safer work environments.

Link to the original journal article:
https://onlinelibrary.wiley.com/doi/full/10.1002/1348-9585.12207

Title of the paper:
Indium concentration in serum is an excellent predictor for assessing accumulated indium concentration in the lungs

Authors:
Miyuki Hirata, Makiko Nakano, Akiyo Tanaka, Kazuyuki Omae

DOI:
10.1002/1348-9585.12207