title: Autophagy--A free meal in sickness-associated anorexia.
abstract: Activation of the immune system is metabolically costly, yet a hallmark of an infection is a reduction in appetite with a subsequent reduction in metabolite provision. What is the functional value of decreasing nutrient intake when an infection imposes large demands on metabolic parameters? Here, we propose that sickness-associated anorexia (SAA) upregulates the ancient process of autophagy systemically, thereby profoundly controlling not only immune- but also nonimmune-competent cells. This allows an advanced impact on the resolution of an infection through direct pathogen killing, enhancement of epitope presentation and the contribution toward the clearance of noxious factors. By rendering a 'free meal,' autophagy is thus most fundamentally harnessed during an anorexic response in order to promote both host tolerance and resistance. These findings strongly suggest a reassessment of numerous SAA-related clinical applications and a re-evaluation of current efforts in patient care.
authors.affiliation: a Department of Physiological Sciences , Stellenbosch University , Stellenbosch , South Africa.
authors.forename: Gustav
authors.initials: G
authors.lastname: van Niekerk
authors.affiliation: b Department of Physiological Sciences , Faculty of Natural Sciences, Stellenbosch University , Stellenbosch , South Africa.
authors.forename: Ben
authors.initials: B
authors.lastname: Loos
authors.affiliation: b Department of Physiological Sciences , Faculty of Natural Sciences, Stellenbosch University , Stellenbosch , South Africa.
authors.forename: Theo
authors.initials: T
authors.lastname: Nell
authors.affiliation: b Department of Physiological Sciences , Faculty of Natural Sciences, Stellenbosch University , Stellenbosch , South Africa.
authors.forename: Anna-Mart
authors.initials: AM
authors.lastname: Engelbrecht
mesh_terms: D000596:Amino Acids / Q000097:blood; D000855:Anorexia / Q000097:blood / Q000473:pathology*; D001343:Autophagy; D006801:Humans; D008099:Liver / Q000473:pathology; D008954:Models, Biological
chemical_list: D000596:Amino Acids
keywords: anorexia; autophagy; infection; sickness behavior; xenophagy