Laser Ablation coupled to ICP/MS provides multi-elemental resolutive spatial distribution in tissues

Pierre ALLAUME¹, Johann LE MAITRE^2,3, Bruno TURLIN^1,4, Marie-Laure ISLAND^2,3, Patricia LEROYER^3,4, Marie SURGET^3,4, Edouard BARDOU-JACQUET^4,5, Martine ROPERT-BOUCHET^2,3,4, Olivier LORÉAL^3,4

¹Department of Pathology, University Hospital, Rennes, France
²Department of Biochemistry Toxicology, University Hospital, Rennes, France
³Elemental Analysis and Metal Metabolism platform (AEM2), University of Rennes, University Hospital, Rennes, France
⁴INSERM, Univ Rennes, INRAe, UMR 1317, Nutrition, Metabolisms and Cancer Institute (NuMéCan), Rennes, France. , Rennes, France
⁵Liver Diseases Department Department of Liver Diseases, University Hospital, Rennes, France

Background : Iron and other essential metals contribute to homeostasis. Metal metabolisms imbalance favors the appearance or progression of diseases. In tissues, metal concentration is measured biochemically as a whole, but this does not inform on the localization of metals. Specific stains for iron and copper can be used but their sensitivity is low. Being able to assess in tissue samples the parallel localization of these metals would help to evaluate their role the progression of diseases.

Aim : Our objective was to image metals in paraffin embedded human liver biopsies by using laser ablation-inductively coupled mass spectrometry (LA-ICP-MS) in order to evaluate the interest of the method.

Methods: Liver samples were collected in Rennes Hospital, from patients exhibiting genetic hemochromatosis or Wilson’s disease. In addition, the cerebellum of normal rats was investigated to evaluate the input of LA-ICP-MS on metal location in a architecturally heterogenous tissue. Fe, Cu, Zn, Se and Mg distributions were analyzed.

Results: LA-ICP-MS demonstrates local iron and copper distribution in the liver of patients, thus giving additional information to the concentration level. Distribution of other metals, unable to evaluate by histological staining, can also be evaluated. Local quantification of iron and copper can be performed. In the cerebellum, close to Purkinje cells line, iron and copper, not detected using classical staining, were found.

Conclusion: LA-ICP-MS is a highly sensitive and resolutive method for simultaneous location of metals in paraffin embedded samples. This method opens new opportunities for studying iron and metal homeostasis disorders.