Teresinha Leal’s research on the identification of biomarkers in the sweat gland to evaluate the efficacy of treatment of Cystic Fibrosis

One project, “MucoSweatOmics”, funded by the FNRS, is conducted in collaboration with Dr. Gabriel Mazzucchelli, PI, and Dr. Bastien Burat, a postdoctoral fellow, both at the Laboratory of Mass Spectrometry of the University of Liège. In this study, proteome, peptidome and metabolome of sweat and sweat glands are characterized and their dynamic functional interactomes are drawn. Moreover, after MALDI imaging mass spectrometry (MALDI-IMS) and profiling, laser microdissection is carried out in the different portions of the gland. After having built reference values in healthy controls, the OMICS strategies will soon be applied to samples collected from patients with CF thanks to a collaboration with Dr Elke De Wachter from the CF reference centre of UZ-Brussel (VUB). Over the past twenty years, the group of Teresinha Leal has been working on Cystic Fibrosis (CF), the most common lethal genetic disease worldwide affecting multiple organs and systems. The group is currently involved in several basic and clinical research projects. Two of them aim at identifying new non-invasive biomarkers of CF Transmem brane conductance Regulator (CFTR) in sweat and in eccrine sweat glands to allow evaluating the efficacy of novel CFTRdirected strategies.

Another research project, “Bubble test”, has been developed at the T Leal’s lab by using a non-invasive protocol in which multiple intra dermal injections have been replaced by iontophoresis or by its variant, electroosmosis. Iontophoresis has been used for decades in routine tests in small children. In collaboration with Prof. Raphael Frédérick, a chemist from UCLouvain, the focus has been set on the physicochemical properties of the non-ionized drugs used during the test, particularly isoproterenol, to promote its penetration into the skin by electroosmosis. The method of the Bubble test is very simple: the stimulated skin area is covered with a thin layer of oil, of which the area is delimited by a well. Sweat secretion, a watery solution, is visualized as droplets or “bubbles” at the surface of the skin using a camera with a macro lens coupled to a computer. Serial images are taken every 30 seconds for 10 minutes during the first cholinergi cally evoked phase of the test, then for 30 minutes during the second -adrenergically evoked phase of the test. In collaboration with Dr. Manuel Nietert at the University of Goettingen, the AutoBuSTeD software has been developed to circumvent limitations of manual i mage analysis that is labor-intensive and operator-dependent. AutoBuSTeD automatically identifies “bubbles” present in the whole series of images taken during each phase of the test and thereafter computes the time-dependent changes of their circumferences. During the CFTRdependent -adrenergic phase of the test, “bubbles” from patients with CF do not grow over time in contrast to healthy controls.

Both projects benefit from the central contribution of the UCLouvain young investigator Audrey Reynaerts who is qualified to conduct

Serial images are taken every 30 secondes for 10 minutes during the first phase of the test and for 30 minutes during the second phase of test. The second phase is silent in patients with cystic fibrosis and bubbles do not grow over time in patients during this phase. To better visualize tiny bubbles during this phase, they are stained in blue. © LTAP

clinical trials. The projects are in the prospect of personalized medicine (over 2,000 CFTR putative mutations identified) with the hope to offer a treatment, on an individual basis, to each CF patient. Identifying companion biomarkers of efficacy of new CFTR-directed therapies may improve cost-effectiveness of health care. Their suc cess are ensured by the resources and facility available at the Louvain Centre for Toxicology and Applied Pharmacology (LTAP) to which Prof. Teresinha Leal belongs. Created in 2009 and bringing together 10 research directors who lead 8 research groups including 24 researchers and 10 PhD students, LTAP is an internal structure of IREC (Institut de Recherche Expérimentale et Clinique). Thanks to its access to a wide range of technical platforms, it has the expertise to conduct all kinds of in vitro and in vivo experiments.

Louvain Centre for Toxicology and Applied Pharmacology Avenue E. Mounier 53 - B-1200 Brussels - Belgium Tel.: +32 (0)2 764 94 73 - E-mail: teresinha.leal@uclouvain.be - https://uclouvain.be/fr/instituts-recherche/irec/ltap