Day and night: diurnal phase influences the response to chronic mild stress.

Chronic mild stress (CMS) protocols are widely used to create animal models of depression. Despite this, the inconsistencies in the reported effects may be indicative of crucial differences in methodology. Here, we considered the time of the diurnal cycle in which stressors are applied as a possible relevant temporal variable underlying the association between stress and behavior. Most laboratories test behavior during the light phase of the diurnal cycle, which corresponds to the animal's resting period. Here, rats stressed either in their resting (light phase) or active (dark phase) periods were behaviorally characterized in the light phase. When exposure to CMS occurred during the light phase of the day cycle, rats displayed signs of depressive and anxiety-related behaviors. This phenotype was not observed when CMS was applied during the dark (active) period. Interestingly, although no differences in spatial and reference memory were detected (Morris water maze) in animals in either stress period, those stressed in the light phase showed marked impairments in the probe test. These animals also showed significant dendritic atrophy in the hippocampal dentate granule neurons, with a decrease in the number of spines. Taken together, the observations reported demonstrate that the time in which stress is applied has differential effects on behavioral and neurostructural phenotypes.

Energy expenditure regulation via macrophage migration inhibitory factor in obesity and in vitro anti-macrophage migration inhibitory factor effect of Alpinia officinarum Hance extraction.

OBJECTIVE: To compare the resting energy expenditure in different macrophage migration inhibitory factor (MIF) genotypes and to identify the in vitro effects of Alpinia officinarum Hance extract (AOHE) on MIF expression in obese and nonobese persons. METHODS: In the fasting state, obese and nonobese persons were assessed for the measurement of resting energy expenditure rate (REE) by indirect calorimetry. We compared it with the expected amount ([REE measured by indirect calorimetry / predicted REE according to Harris Benedict equations] x 100). Participants were classified into those with normal REE (≥100) vs those with impaired REE (<100). Body composition was analyzed. Real-time polymerase chain reaction was performed using specific primer pairs for MIF messenger RNA, and ß-actin was used as the internal control. RESULTS: The study included 69 obese and 103 non-obese participants. The proportions of MIF genotypes were slightly different in obese and nonobese participants. However, the proportions of MIF genotypes were significantly different in participants with normal REE and those with low REE. The MIF gene was highly expressed in the obese group compared with MIF expression in the nonobese group. Body fat mass and MIF expression were higher in participants with the GG genotype than in the other genotype groups. MIF expression was inversely associated with REE in both groups (r = -0.36, P = .04). After treatment of peripheral blood mononuclear cells with AOHE, MIF expression differed according to MIF genotype. CONCLUSIONS: Our results indicate that AOHE is a major modulator of MIF-dependent pathologic conditions in obesity and are consistent with mounting evidence that defines a regulating role for MIF in cytokine production in an inflammatory state in in vitro studies.

VDR FokI polymorphism and its potential role in the pathogenesis of gestational diabetes mellitus and its complications.

The aim of the study is evaluating the associations of FokI vitamin D receptor (VDR) gene polymorphisms with gestational diabetes mellitus (GDM), and its relations with postpartum metabolic syndrome. In a cohort study, 303 women referred to outpatient clinic of Shariati Hospital. The VDR FokI genotypes were determined. All subjects were followed 6?12 weeks after delivery. The frequencies of Ff, FF, and ff genotypes were 30.4% (49), 63.4% (102), and 6.2% (10), respectively, in healthy pregnancies and 34.5% (49), 54.9% (78), and 10.6% (15), respectively, in GDM patients. The ff genotype was more common in GDM patients. Healthy individuals had higher frequency of F allele, suggesting that F allele may have a role in decreased incidence of GDM. Concerning the GDM risk factors, f allele had significant association with prepregnancy obesity and family history of diabetes. In postpartum follow-up, women who developed metabolic syndrome were significantly older with higher prepregnancy body mass index, had more family history of diabetes, and also their ff genotype was two fold more frequent. Our results indicate a meaningful association between FokI VDR genotypes and an increase risk of GDM in Iranian population as well as its effects on postpartum metabolic syndrome.