Characterization of the Plasma Metallomic Profile to Acute Exercise in Healthy Men and Women (METALEXO)

Among the various trace elements playing a key role in physical performance, iron is probably one of the most studied in the last 30 years. Iron is an essential component of both hemoglobin and myoglobin allowing an optimal oxygen delivery to organs, especially to skeletal muscle. Iron also plays a major role in the mitochondrial respiratory chain, as well as in the activity of numerous enzymes. Recent studies support the existence of a strong interaction between the iron metabolism and the other non-ferrous trace elements including among others zinc, copper or cobalt. The latter, but also other trace element metals could thus play an important role in physical performance. The finality of this project is thus 1) to determine the variations of plasma iron and non-ferrous metals in response to an acute exercise, 2) better understand the interactions between all these metals, 3) to determine if such responses to exercise are different or not depending on sex.

Numerous trace element metals play an essential role in energy metabolism including magnesium, zinc or manganese (Heffernan et al., 2019). Elite men and women athletes with high energy demands consequently needs to compensate with food or drink intakes the lost and/or body misdistribution of these trace element metals during physical exercise. Trace element metals and their interactions in metabolic processes can play an important role in physical performance. However, the modulation of their plasma availability in response to acute exercise remains poorly understood (Heffernan et al., 2019). The Inductively Coupled Plasma Mass Spectrometry (ICP-MS) constitutes an efficient technology to detect and quantify all trace element metals in plasma and erythrocytes to answer this question.

Among the different trace element metals, iron is one of the most studied during the last 30 years. Iron is indeed an essential component of hemoglobin and myoglobin allowing an optimal oxygen delivery to organs, especially to skeletal muscle under contraction. Iron also plays a major role in the mitochondrial respiratory chain, as well as in the activity of numerous enzymes. Iron deficiency, especially in plasma iron availability, exerts deleterious consequences on sport performance by promoting iron deficiency anemia. Endurance athletes frequently exhibit iron deficiency (Sim et al., 2019), but the latter could also impact non-athletic populations, especially women (Mota et al., 2019). Disorders in iron metabolism during intense exercise could depend on several factors including hyperhecpidinemia (Roecker et al., 2005). High plasma hepcidin levels indeed contributes to reduction in plasma iron availability classically observed in elite athletes. Moreover, intravascular hemolysis combined to urinary, gastro-intestinal and/or sweat iron lost, could be also observed during prolonged intense exercise (Peeling et al., 2017). All together, these factors can directly impact functional capacities during physical exercise. Interestingly, recent studies support the existence of a strong interaction between the iron metabolism and the other non-ferrous trace elements including among others zinc, copper or cobalt (Loréal et al., 2014; Cavey et al., 2015). During intense physical exercise, the non-ferrous metals could thus directly or indirectly play a role in the modulation of iron import, storage or export in various kind of cells, and so functional capacities.

In this context, the pilot clinical study aims to characterize the plasma metallomic profile in response to an acute intense exercise in healthy men and women. All the volunteers (n=40) will perform 3 visits in the M2S lab: 1) an inclusion visit including anthropometric measures, dietary and physical activity surveys, 2) a second visit to perform the incremental cycling test, 3) a last visit to perform metabolic measures during a 30-min intense exercise (i.e. 90% of mechanical power at anaerobic threshold). Blood samples will be collected before, at the end of this intense exercise, and after 3 hours of recovery to determine in plasma systemic iron metabolism parameters and the concentrations of 29 non-ferrous metals.

Eligibility Criteria:
Inclusion Criteria:

* BMI between 18 and 25 kg/m²
* Non smoker
* 150-300 min of moderate physical activity or 75-150 min of intensive physical activity per week.
* Written informed consent

Exclusion Criteria:

* Iron metabolism disorders (i.e. genetic hemochromatosis, thalassemia, anemia)
* Cardiovascular risks
* Metabolic diseases (e.g.diabetes)
* Use of non-steroidal anti-inflammatory drugs or aspirin
* Simultaneous participation in another research involving the human person or having recently participated in another research for which the exclusion period has not been completed.