Mitochondrial DNA damage in the hair bulb: can it be used as a noninvasive biomarker of local exposure to low LET ionizing radiation?

Abstract

Purpose: Our aim was to evaluate whether mitochondrial DNA (mtDNA) damage in hair bulbs could be a suitable biomarker for the detection of local exposure to ionizing radiation.

Materials and methods: Mouse hair was collected 4 and 24 hours, 3 and 10 days after single whole-body exposure to 0, 0.1, and 2 Gy radiation. Pubic hair (treated area) and scalp hair (control area) were collected from 13 prostate cancer patients before and after fractioned radiotherapy with an average total dose of 2.7 Gy to follicles after five fractions. Unspecified lesion frequency of mtDNA was analyzed with long PCR, large mtDNA deletion levels were tested with real-time PCR.

Results: Unspecified lesion frequency of mtDNA significantly increased in mouse hair 24 hours after irradiation with 2 Gy, but variance among samples was high. No increase in lesion frequency could be detected after 0.1 Gy irradiation. In prostate cancer patients, there was no significant change in either the unspecified lesion frequency or in the proportion of 4934-bp deleted mtDNA in pubic hair after radiotherapy. The proportions of murine 3860-bp common deletion, human 4977-bp common deletion and 7455-bp deleted mtDNA were too low to be analyzed reliably.

Conclusions: Our results suggest that the unspecified lesion frequency and proportion of large deletions of mtDNA in hair bulbs are not suitable biomarkers of exposure to ionizing radiation.

Keywords:

• Biodosimetry
• common deletion
• mtDNA lesions
• hair
• ionizing radiation
• long PCR

Acknowledgements

The authors are grateful to N. Sándor and L. Szőllősi for help in the experimental procedure with mice. The authors thank A. Juutilainen, A. Palomaa, K. Tervo, and P. Vesterinen for collecting the human hair samples.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The research received funding from the European Union’s Seventh Framework Program (EURATOM FP7/2007-2013) under Grant agreement no. 604984 (OPERRA), the Euratom Research and Training Program 2014–2018 under grant agreement no. 662287 (CONCERT), and from the National Research, Development and Innovation Office [grant number: VKSZ 14-1-2015-0021].

Notes on contributors

Rita Hargitai

Rita Hargitai, PhD, is a senior researcher at the Department of Radiation Medicine of the Division of Radiobiology and Radiohygiene of the National Public Health Center in Budapest, Hungary

Päivi Roivainen

Päivi Roivainen, PhD, is a senior researcher at the Department of Environmental and Biological Sciences of the University of Eastern Finland in Kuopio, Finland.

Dávid Kis

Dávid Kis is a PhD student at Semmelweis University and a researcher at the Department of Radiation Medicine of the Division of Radiobiology and Radiohygiene of the National Public Health Center in Budapest, Hungary

Jukka Luukkonen

Jukka Luukkonen, PhD, is a senior lecturer at the Department of Environmental and Biological Sciences of the University of Eastern Finland in Kuopio, Finland.

Géza Sáfrány

Géza Sáfrány, MD, PhD, DSc, is the head of the Division of Radiobiology and Radiohygiene of the National Public Health Center in Budapest, Hungary.

Jan Seppälä

Jan Seppälä, PhD, is adjunct professor and chief physicist at the Center of Oncology of the Kuopio University Hospital in Kuopio, Finland

Tünde Szatmári

Tünde Szatmári, PhD, is a senior researcher at the Department of Radiation Medicine of the Division of Radiobiology and Radiohygiene of the National Public Health Center in Budapest, Hungary

Tuomas Virén

Tuomas Virén, PhD, is adjunct professor and a medical physicist at the Center of Oncology of the Kuopio University Hospital in Kuopio, Finland

Kristiina Vuolukka

Kristiina Vuolukka, MD, is a medical oncologist at the Center of Oncology of the Kuopio University Hospital in Kuopio, Finland

Sisko Salomaa

Sisko Salomaa, PhD, is professor of radiobiology at the Department of Environmental and Biological Sciences of the University of Eastern Finland in Kuopio, Finland, leading the OPERRA project task on biomarkers and biobanking.

Katalin Lumniczky

Katalin Lumniczky, MD, PhD, is the head of the Department of Radiation Medicine of the Division of Radiobiology and Radiohygiene of the National Public Health Center in Budapest, Hungary