Chronobiological features of the immune system. Effect of calorie restriction

Cano

Jiménez-Ortega

et al. 2007

Endocr

Virtually all neuroendocrine and immunological variables investigated in animals and humans display biological periodicity. Circadian rhythmicity is revealed for every hormone in circulation as well as for circulating immune cells, lymphocyte metabolism and transformability, cytokines, receptors, and adhesion molecules. Clock genes, notably the three Period (Per1/Per2/Per3) genes and two Cryptochrome (Cry1/Cry2) genes, are present in immune and endocrine cells and are expressed in a circadian manner in human cells. This review discusses the circadian disruption of hormone release and immune-related mechanisms in several animal models in which circulating cytokines are modified including rat adjuvant arthritis, social isolation in rats and rabbits and alcoholism, the aging process and calorie restriction in rats. In every case the experimental manipulation used perturbed the temporal organization by affecting the shape and amplitude of a rhythm or by modifying the intrinsic oscillatory mechanism itself.

Section: Caloric Restrictionmentioning

confidence: 99%

Neuroendocrine-immune correlates of circadian physiology: studies in experimental models of arthritis, ethanol feeding, aging, social isolation, and calorie restriction

Cano

Jiménez-Ortega

et al. 2007

Endocr

“…This is a model widely employed in studies on aging, since it slows the aging process in rodents (19). Under calorie restriction the use of energy is greatly reduced and the basal plasma levels of several hormones are altered (4,26). This prompted us to undertake the present study whose objective was to analyze the effect of calorie restriction on EAE induction in Lewis rats.…”

Section: Et Almentioning

confidence: 99%

Experimental allergic encephalomyelitis in male Lewis rats subjected to calorie restriction

Cano

Jiménez

et al. 2004

J. Physiol. Biochem.

This work analyzes the effect of calorie restriction on the development of experimental allergic encephalomyelitis (EAE) in Lewis rats. Plasma levels of ACTH, corticosterone, prolactin and growth hormone (GH) and mitogenic responses in submaxillary lymph nodes were measured. Male Lewis rats (6 weeks-old) were submitted to a calorie restriction equivalent to 66% of food restriction or to a normal diet. Fifteen days later, rats were injected with complete Freund's adjuvant plus spinal chord homogenate (SCH) or with complete Freund's adjuvant alone. Rats were monitored daily for clinical signs of EAE and were killed on day 15 after immunization. Only rats subjected to normal diet exhibited clinical signs of the disease. The increase in plasma ACTH and corticosterone found after SCH immunization in controls was not detectable in calorie restricted rats. Likewise, the correlation between circulating ACTH and corticosterone was no longer found after calorie restriction. Generally, calorie restriction by itself augmented plasma ACTH or corticosterone and this increase was not further amplified by SCH immunization. Only calorie restricted rats exhibited augmented plasma prolactin levels after SCH immunization, and decreased plasma GH levels regardless of immunization. Calorie restriction depressed the mitogenic response of lymphoid cells to concanavalin A but not to lipopolysaccharide. Calorie restricted rats did not exhibit augmented mitogenic response to concanavalin A following SCH immunization as those found in controls. The results are compatible with the view that the course of EAE can be significantly modified by caloric restriction.

“…Under calorie restriction, plasma levels of several hormones are modified (Brogan et al, 1997;Chacon et al, 2002;Wronska et al, 1990). Among them, the hormones of the pituitary-gonadal axis have been extensively studied, mostly using single time-of-day sampling (Caprio et al, 2001;Clark et al, 1998;Sprangers and Piacsek, 1997).…”

Section: Introductionmentioning

confidence: 99%

24‐Hour Changes in ACTH, Corticosterone, Growth Hormone, and Leptin Levels in Young Male Rats Subjected to Calorie Restriction

Chacón

Chronobiology International

Perelló

et al. 2005

Calorie restriction of young male rats increases plasma prolactin, decreases luteinizing hormone (LH) and testosterone, and disrupts their 24 h secretory pattern. To study whether this could be the consequence of stress, we examined the 24 h variations of plasma adrenocorticotropic hormone (ACTH) corticosterone, growth hormone (GH), leptin, and adrenal corticosterone. Rats were submitted to a calorie restriction equivalent to a 66% of usual intake for 4 weeks, starting on day 35 of life. Controls were kept in individual cages and allowed to eat a normal calorie regimen. Significantly lower ACTH levels were detected in calorie-restricted rats. Plasma corticosterone levels during the light phase of the daily cycle were significantly higher in calorie-restricted rats. Time-of-day variation in plasma ACTH and corticosterone levels attained significance in calorie-restricted rats only, with a maximum toward the end of the resting phase. The daily pattern of adrenal gland corticosterone mirrored that of circulating corticosterone; however, calorie restriction reduced its levels. Plasma ACTH and corticosterone correlated significantly in controls only. Calorie restriction decreased plasma GH and leptin, and it distorted 24h rhythmicity. In a second study, plasma ACTH and corticosterone levels were measured in group-caged rats, isolated control rats, and calorie-restricted rats during the light phase of the daily cycle. Plasma ACTH of calorie-restricted rats was lower, and plasma corticosterone was higher, compared with isolated or group-caged controls. The changes in the secretory pattern of hormones hereby reported may be part of the neuroendocrine and metabolic mechanisms evolved to maximize survival during periods of food shortage.