Polarization of M1 and M2 monocytes / macrophages in sedentary and trained individuals: potential role of adipose tissue and leptin

• Grant number: 18/11443-4
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): March 01, 2019
• Effective date (End): February 29, 2020
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Fábio Santos de Lira
• Grantee: Caíque de Figueiredo
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

Derived from a myeloid lineage in the bone marrow, monocytes are blood cells of the immune system that when they infiltrate the tissues differentiate into macrophages of anti-inflammatory (M2) or pro-inflammatory (M1) state. The M1 phenotype is predominant in white adipose tissue (WAT) of obese subjects, it effectively participates in the release of pro-inflammatory cytokines during low-grade chronic inflammation and exhibits a predominance of glycolytic metabolism. On the other hand, the M2 phenotype is mostly found in the WAT of eutrophic individuals, secretes cytokines that mediate the anti-inflammatory response, presents oxidative metabolism and its polarization is marked by the practice of physical exercise. Thus, the balance between M1 and M2 is essential for health maintenance and both body composition and physical conditioning play an important role. Leptin is a hormone released mainly by WAT that has central and peripheral functions, among them, regulation of appetite, energy expenditure and modulation of the immune response. In monocytes, this hormone is able to stimulate the activation, proliferation and secretion of these cells. However, the response of monocytes to polarization stimuli for the M1 or M2 phenotype, with and without leptin administration in individuals who are overweight / obese (especially visceral fat), even exhibiting good physical conditioning may be different from eutrophic individuals with different levels of physical fitness.