Medical geology

(ISTerre geochemistry: L. Charlet, A. Gourlan; Volcanology: V. Pinel)

The Medical Geochemistry group is made up of researchers from a variety of backgrounds (geochemistry, mineralogy, volcanology, etc.) at ISTerre, other French institutions (IGE-Grenoble, IAB-Grenoble, ILM-Lyon, ENS-Lyon, Vetagro-sup, Laboratoire écologie fonctionnelle et environnement) and abroad (Berkeley University, USA; Swansea University, UK).

The group’s primary research focus is on understanding the bio-geochemical processes that control the development of diseases (Podoconiosis, KBD, thyroid cancer) and their treatment (e.g. ovarian cancer). Understanding the history of their development enables us to identify the mechanisms of human-environment transfer of (nano)particles (imogolite nanotubes, silver nanotubes, selenium nanoparticles), trace elements (e.g., oxyanions, strategic metals...), including transfer to humans via crops, and their role in the biodiversity of the tropical belt. Ultimately, this knowledge is used to develop public health prevention strategies with local stakeholders and scientific partners. This multi-disciplinary research is being carried out on two main sites The East African Rift (Rwanda, Uganda) and North Africa (Algeria).

The group then focuses on the potential of ∂65Cu as a biomarker of cancer and its progression, and more generally as a marker of health status in the animal kingdom (domesticated and wild animals). Although promising biomarkers (transcriptomics, metabolomics and proteomics) currently exist in the veterinary field, many are misdiagnosed and not pathognomonic for disease. Early studies using Cu isotope as a cancer biomarker in humans have been very encouraging, suggesting that this approach can be applied to dogs. In addition, in recent decades, anthropogenic activities and global climate change have become geographical limitations for many wild species, resulting in niche modifications associated with visible examples of genetic bottlenecks, exposure to stress, toxins or oncogenic pathogens and immunosuppression. All these factors have contributed to the development of cancer in wild species. It therefore became clear that neoplasia could be widespread and have considerable effects on certain species, and that it was vital to pay particular attention to wildlife conservation.

SeCuCo project: Use of Selenium nanoparticles and Copper isotopes for the treatment and monitoring of ovarian cancer

(ISOTOP Challenge - AAP 2018-2019, Correspondent A. Gourlan)

Medicine routinely uses unstable isotopes in medical imaging (scintigraphy, PET, SPECT) to obtain a functional diagnosis of an organ. Unconventional stable isotopes such as transition metals (Cu, Zn, Fe) are only just beginning to be used in veterinary and human medicine as tracers of pathological conditions, leading for example to cancer. This larger research project aims to couple the use of aqueous and nanoparticulate Se (Se-NP), for their therapeutic effects on ovarian cancer, and Copper isotopes, as a potential biomarker of cancer and its progression, to monitor their effects. In addition to testing the efficacy of aqueous Se-NP/Se treatment, this project aims to improve our understanding of the mechanisms involved in Cu isotope fractionation during cancer development and treatment.

Transgeobio project: Transposing geochemical methods to biology: using copper isotopes as a biomarker of a cancerous condition in the veterinary field

(AAP2017-OSEZ, internal BQR 2016, correspondent A. Gourlan)

This comparative oncology project proposes the use of copper isotopes as tracers of lymphomas and mammary cancers in dogs, to study their mechanisms and progression, and as a test of treatment efficacy. It aims to improve our understanding of copper homeostasis in mammals and its role in cell biology, notably in the functioning of membrane transporters, oxidoreductases and intracellular trafficking. This project involves a dynamic collaboration between ISTerre, LBFA, which has experience in animal metallomics (J.-M. Moulis), Vetagro-sup Lyon (F. Ponce), which has a large bank of biological samples from domestic animals (CRB-ANIM), and ENS Lyon (P. Télouk, F. Albarède), which has filed a patent on the use of isotopes in biology/medicine.

Project Understanding the availability and transfer of chemical elements in Arctic terrestrial food chains and quantifying health implications for wildlife

(ANR ATACAF 2021-2024, PI S. Hansson, corresponding ISTerre A. Gourlan)

The Arctic is one of the regions being strongly impacted by global warming, which modifies the biogeochemical processes involved in the bioavailability and transfer of essential (e.g. Cu, Zn, Se) and non-essential (e.g. Pb, Cd, Hg) elements. At the same time, human presence in the region is increasing due to increased oil and mining exploration/extraction, all with the risk of negative environmental consequences. One of the tasks of this ANR project is to study the Cu isotopic composition of blood samples from large wild Arctic animals as a health diagnostic tool (e.g. neoplasia, inflammation, body condition, pathogens).

Project Societal impact of volcanic activity in Rwanda: contribution of geophysics and geochemistry

(BQR ISTerre, 2023-2024, corresponding V. Pinel and L. Charlet)

Rwanda, a small country on the East African Rift, is highly exposed to volcanic hazards, with three active volcanoes on its territory and two very active volcanoes located in the Democratic Republic of Congo in the immediate vicinity of its border. This project aims to characterize the potential impact of this hazard on the population. It focuses on the long-term effects of volcanic deposits, with a study of the link between the development of the "elephant’s foot" disease, podoconiosis, in a population and its location on volcanic soils. In addition to Rwanda, podoconiosis affects 4 million people in 27 countries, including 18 in Africa. It also addresses volcanic risk by focusing on the physical conditions (tectonic constraints, local topography and bathymetry, and magma composition) controlling the location of the magma arrival zone at the surface near - or under - Lake Kivu, rich in CH4 and CO2, whose potential destabilization represents a major risk of limnic eruption. The project is financing two field campaigns, one in June by V. Pinel, the other in December 2023 by L. Charlet.

E-DOOR project

(UNESCO-IGCP) (correspondent: L. Charlet)

UNESCO project, develops a project focused on educating local stakeholders about the impact of volcanic activity (dispersion of volcanic gas and ash, monitoring of Lake Kivu, health and social survey, biodiversity in the Volcanic environment). The project will study the environmental dynamics of Rwanda’s western volcanic province. This region features complex interactions between the volcanic activity of Mount Nyiragongo in D.R. Congo and its frequent magmatic intrusions, Lake Kivu, a volcanic lake extremely rich in dissolved methane and carbon dioxide in its deep waters, and the surrounding local population, whose resources are agriculture and fishing. The challenges facing the population living in western Rwanda, particularly in the town of Gisenyi ( 90,000 inhabitants), are manifold: from volcanic hazards, including lava flows, earthquakes and volcanic plumes, to the danger of massive lake outgassing (gas-fed limnic eruption) that would cause asphyxiation and/or the spread of podoconiosis, a severe and debilitating swelling of the lower limbs. This project will identify the main drivers of dynamics in the region, using different but complementary approaches: theoretical and numerical modeling in physical volcanology, data analysis of physico-chemical and phytoplankton assemblages in Lake Kivu, study of surrounding soils and socio-ecological analysis of the relationship between human and environmental health in the region. It will enable us to strengthen our partnership in Rwanda and, with two UNESCO category 2 institutes of the University of Rwanda (ICTP-EAIFR and CoEB), to submit multidisciplinary projects currently under construction (JEAI IRD project, US-NSF project see below) focusing on the health, societal and ecological impacts of volcanic activity in the East African Rift.

IRGA project

The project aims to deepen our understanding of the biological mechanisms that of foot exposure to volcanic particles leading to podoconiosis. It has two components: (1) to produce dose-response curves for the exposure of macrophages (present in the nodes of the lymphatic system that these particles obstruct) to imogolite nanotubes, interpreted if possible with synchrotron nanotomography of macrophages thus exposed, and (2) to study podoconiosis biopsies from the African Rift already obtained from the University of Sussex (UK), comparing the elemental imaging obtained by LIBS (in collaboration with V. Motto-Ros, ILM Lyon 1 and B. Busser, IAB-CHUG), with LA-ICPMS (MEET analytical platform at ISTerre). The project falls directly within the framework of the "Plateforme d’imagerie de la distribution des métaux et métalloides dans les tissus biologiques: applications biomedicales et environmentales", a strategy developed by ISTerre and UGA to co-finance part of the MEET platform. The ultimate aim is to develop a national facility to use the remarkable MEET analytical platform in conjunction with the LIBS facility soon to be acquired at IAB-CHUG for rapid diagnosis of such neglected particle-induced tropical diseases. Access to these facilities will be faster than the slow and difficult, but complementary, access to imaging techniques developed at ESRF.

Project Formation and bioavailability of Imogolite in Volcanic Soils

(US-NSF, under construction)

This project led by Dr. Ben Gilbert (Uni. Berkeley and LBLN) in collaboration with L. Charlet aims to develop a reactive transport model describing the formation of imogolite nanotubes from volcanic ash, with areas of high prevalence of this disease corresponding to areas of ash fallout. The literature on the subject shows that this formation is dependent on rainfall in these mountainous areas, which were settled by farmers in the 1960s. Over and above the formation of nanotubes in volcanic environments, the model aims to assess the effect of climate change on this formation, and therefore on the development of podoconiosis in Rwanda and worldwide in the future. Among other things, the impact of SOM soil organic matter degradation (linked to agricultural use and climate change) on the bioavailability of imogolite nanotubes to humans will be assessed by micro-calorimetric experiments on the competition between SOM and cell membrane phospholipids for their retention by imogolite. This project relies on the extensive development of field measurements and sampling, in partnership with the Department of Soil Science at the University of Rwanda, and on the analytical power of Berkeley.