Yann Ravussin

Over­feed­ing and Neur­al Path­ways that Reg­u­late Body Weight

Abstract

While the esca­lat­ing pub­lic health cri­sis pre­sent­ed by obe­si­ty and adi­pos­i­ty-relat­ed meta­bol­ic dis­or­ders is well-rec­og­nized, ther­a­peu­tic strate­gies remain few, pri­mar­i­ly due to an incom­plete com­pre­hen­sion of body weight and adi­pose mass reg­u­la­tion mech­a­nisms. The impor­tance of dis­cern­ing periph­er­al and neu­ronal cir­cuits mod­u­lat­ing caloric intake and ener­gy expen­di­ture can­not be over­stat­ed. While exten­sive research has elu­ci­dat­ed the neu­ronal cir­cuits increas­ing food con­sump­tion fol­low­ing weight loss, the inverse path­ways — those cur­tail­ing feed­ing behav­ior and aug­ment­ing meta­bol­ic rate dur­ing peri­ods of over­con­sump­tion — remain com­par­a­tive­ly under­stud­ied and poor­ly under­stood. This gap in knowl­edge is large­ly due to a dearth of suit­able exper­i­men­tal paradigms.

To address this, we have engi­neered a gas­tric intu­ba­tion pro­ce­dure facil­i­tat­ing large vol­ume caloric infu­sion in mice, result­ing in rapid weight gain. Upon ces­sa­tion of over­feed­ing, a hypophag­ic peri­od ensues whose length is pro­por­tion­al to the weight gained and returns mice to their weight pri­or to over­feed­ing. This obser­va­tion sug­gests the exis­tence of an anorec­tic fac­tor that com­mu­ni­cates somat­ic ener­gy reserves to the brain, sub­se­quent­ly reduc­ing food intake.

We have pro­posed that the pro­duc­tion of this sig­nal emanates from the periph­ery (poten­tial­ly the adi­pose tis­sue) and acts on the brain to decrease feed­ing behav­ior until excess weight is lost. I will present data relat­ed to our most recent findings.

Biog­ra­phy

Yann Ravussin, Ph.D., is cur­rent­ly a senior lecturer/​group leader and direc­tor of the Mouse Meta­bol­ic Phe­no­typ­ing Plat­form at the Uni­ver­si­ty of Fri­bourg’s Fac­ul­ty of Sci­ence and Med­i­cine. Since join­ing the Uni­ver­si­ty of Fri­bourg in Feb­ru­ary 2020, Dr. Ravussin received the Young Inde­pen­dent Inves­ti­ga­tor Award (from the Swiss Soci­ety of Endocrinol­o­gy and Dia­betes) to fur­ther his research relat­ed to under­stand­ing the mol­e­c­u­lar under­pin­nings of body weight reg­u­la­tion that had been start­ed dur­ing a post­doc­tor­al fel­low­ship at Colum­bia Uni­ver­si­ty. He is par­tic­u­lar­ly inter­est­ed in under­stand­ing how periph­er­al sig­nals (com­ing from var­i­ous tis­sues) can influ­ence the brain and change ener­gy intake and expen­di­ture dur­ing alter­ations in body weight.

Pre­vi­ous to his arrival in Fri­bourg, he obtained his Master’s at the Uni­ver­si­ty of Lau­sanne in Switzer­land and his PhD at Colum­bia Uni­ver­si­ty in New York City. He then con­duct­ed post­doc­tor­al work at the Nation­als Insti­tutes of Health (NID­DK) and again at Colum­bia Uni­ver­si­ty (with Dr. Fer­rante – first to describe macrophages in adi­pose tis­sue). He has pub­lished papers on a host of dif­fer­ent areas relat­ed to metab­o­lism and meta­bol­ic health includ­ing micro­bio­ta, neu­roen­docrinol­o­gy, and dia­betes in high impact jour­nals such as Cell Metab­o­lism and Obe­si­ty. Fur­ther­more, he is a board mem­ber of the Swiss Asso­ci­a­tion for Endocrinol­o­gy Metab­o­lism and Obe­si­ty Stud­ies (ASE­MO).

Out­side of his pro­fes­sion­al life, Dr. Ravussin is an avid run­ner and pas­sion­ate world trav­el­er. He also main­tains a keen inter­est in the influ­ence of lan­guage on per­son­al identity.