HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Published online before print June 25, 2008

This Article Full Text (Reprint (PDF)) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Dixit, V. D. PubMed PubMed Citation Articles by Dixit, V. D.

© by The Society for Leukocyte Biology
Journal of Leukocyte Biology, doi:10.1189/jlb.0108028

Received for publication January 14, 2008.
Revised April 23, 2008.
Accepted for publication April 25, 2008.

Article

Adipose-immune interactions during obesity and caloric restriction: reciprocal mechanisms regulating immunity and health span

Laboratory of Neuroendocrine-Immunology, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA

^@ To whom correspondence should be addressed. E-mail: Vishwa.dixit{at}pbrc.edu.

	Abstract

Increasing evidence suggests a tight coupling of metabolic and immune systems. This cross-talk mediated by neuroendocrine peptides as well as numerous cytokines and chemokines is believed to be responsible for integrating energy balance to immune function. These neuroendocrine-immune interactions are heightened during the state of chronic positive energy balance, as seen during obesity, and negative energy balance caused by caloric restriction (CR). Emerging evidence suggests that obesity may be associated with an immunodeficient state and chronic inflammation, which contribute to an increased risk of premature death. The direct interactions between expanded leukocyte populations within the adipose tissue during obesity and an increased number of adipocytes within an aging lymphoid microenvironment may constitute an important adaptive or pathological response as a result of change in energy balance. In stark contrast to obesity, CR causes negative energy balance and robustly prolongs a healthy lifespan in all of the species studied to date. Therefore, the endogenous neuroendocrine-metabolic sensors elevated or suppressed as a result of changes in energy balance may offer an important mechanism in understanding the antiaging and potential immune-enhancing nature of CR. Ghrelin, one such sensor of negative energy balance, is reduced during obesity and increased by CR. Ghrelin also regulates immune function by reducing proinflammatory cytokines and promotes thymopoiesis during aging and thus, may be a new CR mimetic target. The identification of immune effects and molecular pathways used by such orexigenic metabolic factors could offer potentially novel approaches to enhance immunity and increase a healthy lifespan.

Key Words: orexigenic • CR mimetic • anorexigenic • AMPK • NF-B • mTOR • food intake • dietary • nutrition • immunity • ghrelin • GHS-R • inflammation • aging • leptin • IL-6 • thymus • bone marrow • NeuroImmune • TNF • macrophage • T cells