Caloric restriction in humans reveals immunometabolic regulators of health span.

The extension of life span driven by 40% caloric restriction (CR) in rodents causes trade-offs in growth, reproduction, and immune defense that make it difficult to identify therapeutically relevant CR-mimetic targets. We report that about 14% CR for 2 years in healthy humans improved thymopoiesis and was correlated with mobilization of intrathymic ectopic lipid. CR-induced transcriptional reprogramming in adipose tissue implicated pathways regulating mitochondrial bioenergetics, anti-inflammatory responses, and longevity. Expression of the gene Pla2g7 encoding platelet activating factor acetyl hydrolase (PLA2G7) is inhibited in humans undergoing CR. Deletion of Pla2g7 in mice showed decreased thymic lipoatrophy, protection against age-related inflammation, lowered NLRP3 inflammasome activation, and improved metabolic health. Therefore, the reduction of PLA2G7 may mediate the immunometabolic effects of CR and could potentially be harnessed to lower inflammation and extend the health span.

Metabolically healthy and unhealthy obese--the 2013 Stock Conference report.

Obesity is closely associated with cardiovascular diseases and type 2 diabetes, but some obese individuals, despite having excessive body fat, exhibit metabolic health that is comparable with that of lean individuals. The 'healthy obese' phenotype was described in the 1980s, but major advancements in its characterization were only made in the past five years. During this time, several new mechanisms that may be involved in health preservation in obesity were proposed through the use of transgenic animal models, use of sophisticated imaging techniques and in vivo measurements of insulin sensitivity. However, the main obstacle in advancing our understanding of the metabolically healthy obese phenotype and its related long-term health risks is the lack of a standardized definition. Here, we summarize the proceedings of the 13th Stock Conference of the International Association of the Study of Obesity. We describe the current research and highlight the unanswered questions and gaps in the field. Better understanding of metabolic health in obesity will assist in therapeutic decision-making and help identify therapeutic targets to improve metabolic health in obesity.

Association of white blood cell subfraction concentration with fitness and fatness.

OBJECTIVE: To examine the association between fitness, BMI, and neutrophil, lymphocyte, monocyte, basophil, and eosinophil concentrations in apparently healthy, non-smoking men. DESIGN: Cross-sectional study of 452 men from the Aerobics Center Longitudinal Study examining the resting concentration of white blood cell subfractions across fitness (maximal METs during a treadmill exercise test) and fatness (BMI) categories after adjusting for age. RESULTS: Fitness was inversely associated with all WBC subfraction concentrations. After further adjustment for BMI, only total WBC, neutrophil, and basophil concentrations remained significantly associated with fitness. BMI was directly associated with total WBC, neutrophil, lymphocyte, monocyte, and basophil concentrations and, when fitness was added to the model, only monocytes lost significance. CONCLUSION: Fitness (inversely) and fatness (directly) are associated with WBC subfraction populations.

Identification of genes differentially expressed in T cells following stimulation with the chemokines CXCL12 and CXCL10.

BACKGROUND: Chemokines are involved in many biological activities ranging from leukocyte differentiation to neuronal morphogenesis. Despite numerous reports describing chemokine function, little is known about the molecular changes induced by cytokines. METHODS: We have isolated and identified by differential display analysis 182 differentially expressed cDNAs from CXCR3-transfected Jurkat T cells following treatment with CXCL12 or CXCL10. These chemokine-modulated genes were further verified using quantitative RT-PCR and Western blot analysis. RESULTS: One hundred and forty-six of the cDNAs were successfully cloned, sequenced, and identified by BLAST. Following removal of redundant and non-informative clones, seventeen mRNAs were found to be differentially expressed post treatment with either chemokine ligand with several representing known genes with established functions. Twenty-one genes were upregulated in these transfected Jurkat cells following both CXCL12 and CXCL10, four genes displayed a discordant response and seven genes were downregulated upon treatment with either chemokine. Identified genes include geminin (GEM), thioredoxin (TXN), DEAD/H box polypeptide 1 (DDX1), growth hormone inducible transmembrane protein (GHITM), and transcription elongation regulator 1 (TCERG1). Subsequent analysis of several of these genes using semi-quantitative PCR and western blot analysis confirmed their differential expression post ligand treatment. CONCLUSIONS: Together, these results provide insight into chemokine-induced gene activation and identify potentially novel functions for known genes in chemokine biology.

Growth hormone secretagogue (GHS) analogue, hexarelin stimulates GH from peripheral lymphocytes.

The role of growth hormone releasing hormone (GHRH) and growth hormone releasing peptide-6 (GHRP-6) analogue hexarelin was investigated in the regulation of GH production from lymphocytes. Porcine and bovine blood mononuclear cells were separated using density gradient centrifugation method by layering the whole blood or buffy coat cells on lymphodex. Cells were incubated for 3 or 5 days with or without phytohemagglutinin (PHA-M), GHRH, GHRP-6 analogue hexarelin, somatostatin or GHRH + hexarelin. Growth hormone was fractionated from supernatants by gel chromatography and further concentrated by lyophilization at - 20 degrees C. A nearly two fold increase in basal secretion of GH (porcine: 3.5 +/- 0.1 ng/ml, bovine: 3.2 +/- 0.2 ng/ml) was achieved by GHRH and hexarelin at concentrations of 0.1, 1.0, 10 and 100 nM in both porcine and bovine cells. Lymphocytic GH release was also stimulated in response to PHA-M (10 micro g/well). Neither a dose dependent nor a synergistic nor an additive effect was apparent on GH secretion from lymphocytes. GHRH stimulated lymphocytic GH secretion, whereas, somatostatin had no effect. This study reports for the first time that hexarelin stimulates the secretion of GH from peripheral lymphocytes.

Plasma inhibin levels in relation to steroids and gonadotrophins during oestrous cycle in buffalo.

The study was conducted on six Murrah buffalo synchronized and induced to oestrus. An indwelling catheter was placed in the jugular vein of each buffalo 4 days before the expected onset of the oestrus following the induced oestrus and blood samples were collected at 8 h intervals from each animal throughout the oestrous cycle. Plasma immunoreactive inhibin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol-17 beta and progesterone were estimated by radioimmunoassay to study the variations in the peripheral levels of these hormones and their inter-relationships in order to elucidate the feedback systems controlling them during the oestrous cycle of buffalo. Plasma inhibin levels ranged between 391.25 and 631.97 pg/ml during various phases of the oestrous cycle and were found to be higher than reported in cows. Peak LH and FSH levels during oestrus were 38.40 +/- 9.21 and 24.04 +/- 4.75 ng/ml, respectively and estradiol-17 beta and progesterone were 19.50 +/- 5.51 pg/ml and 0.61 +/- 0.25 ng/ml, respectively. The mean plasma inhibin concentration on the day of oestrus was 562.5 +/- 18.9 pg/ml. Levels of FSH in the plasma showed three mid-cycle elevations which corresponded to comparatively lower inhibin and elevated estradiol-17 beta levels during the same period. From this observation it was deduced that both inhibin and estradiol-17 beta have a feed-back regulatory effect on FSH secretion in buffalo.

Transport stress modulates adrenocorticotropin secretion from peripheral bovine lymphocytes.

The influence of transport stress on the secretion of adrenocorticotropin (ACTH) from peripheral bovine lymphocytes was evaluated by exposing cows to short- (30 min) or long-term (14 h) transport. After transporting animals for 14 h they were given a mandatory rest for 24 h in two different situations, either by off-loading them and allowing them to rest in a stall or by keeping them in the truck. Blood samples were withdrawn before and after transport and after the rest period in long-term transported cows and before and after transport in cows transported for 30 min. Peripheral blood lymphocytes were separated and cultured for 72 h in serum-free medium. Adrenocorticotropin was measured using highly sensitive and specific immunoradiometric assay in culture supernates. We noticed no effect of short-term transport on ACTH secretion from lymphocytes. The ACTH concentration in animals transported for 14 h increased (P < or = 0.01) from 4.72 +/- 0.48 pg x mL(-1)/2 x 10(6) lymphocytes before the transport to 8.24 +/- 1.40 pg x mL(-1) directly after the transport. When animals were off-loaded and rested in a stall for 24 h, ACTH secretion from cultured lymphocytes returned to the basal value of 4.24 +/- 0.31 pg x mL(-1), whereas the animals rested in the truck had ACTH levels of 8.9 +/- 1.43 pg x mL(-1). Phytohemagglutinin, a plant lectin that stimulates lymphocytes, did not affect the lymphocytic ACTH secretion in this study. Heart rate and rectal temperature measured telemetrically increased in cows directly after 14 h of transport but decreased to pretransport values in cows rested for 24 h in cows rested in stalls and those rested inside the truck. This experiment is the first to show lymphocytic ACTH secretion in cows, and the results indicate that ACTH secretion from peripheral lymphocytes could be used as a reliable measurement in stress studies.

Nitric oxide and the control of reproduction.

The free radical gas, nitric oxide is now known to be an important biological messenger in animals. Signal transmission by a gas that is produced by one cell, penetrates through membranes and regulates the function of another cell, represents new principles for signalling in biological systems. Nitric oxide is synthesised from L-arginine by enzyme nitric oxide synthase, which exists in multiple isoforms in a wide range of mammalian cells. Studies conducted in recent years point at a strong influence of NO in a wide range of reproductive functions. It is implicated in the control of gonadotrophin secretion at both hypothalamic and hypophyseal levels, LH surge mechanism, sexual behaviour, estradiol synthesis, follicle survival and ovulation. While considerable work lies ahead in unravelling the role of NO at the peripheral, cellular and molecular level in the domestic animal reproduction, findings presented in this review provide a general overview of growing appreciation of NO as a vital molecule controlling hypothalamic-pituitary-gonadal (HPG) axis.

Pregnancy stimulates secretion of adrenocorticotropin and nitric oxide from peripheral bovine lymphocytes.

The cross-talk between the endocrine and the immune systems mediated by a wide array of hormones, cytokines, and neuromodulators is heightened during disease, stress, and presumably, during pregnancy. Adrenocorticotropin (ACTH) and nitric oxide (NO) are two immunomodulators that are also produced from lymphocytes and contribute to the immunomodulation. Thus, we investigated whether the heightened bidirectional communication between the immune and the endocrine systems observed during pregnancy is reflected in production of ACTH and NO from peripheral bovine lymphocytes and if any temporal correlation exists between them. Adrenocorticotropin was analyzed using a sandwich immunoradiometric assay, and nitrite and nitrate (a measure of NO) were estimated in supernatants of cultured peripheral blood lymphocytes (PBLs) using a colorimetric assay based on the Griess reaction. A significantly high secretion of ACTH and NO was noticed from PBLs in all stages of pregnancy compared to that in cyclic and cystic cows. Increased secretory capacity was noticed as early as 7 days after conception, which reached as much as 600% that of nonpregnant animals between Days 90-120 of gestation. Adrenocorticotropin and NO decline 1 mo before the expected time of parturition. Unlike those from cyclic animals, PBLs from pregnant cows were refractory to stimulation by PHA-M (Phytohemagglutinin) and corticotropin-releasing hormone. A strong correlation was observed between ACTH and NO secretion from PBLs in pregnant, in cyclic, and in cystic cows. To our knowledge, this is the first evidence elucidating the induction of ACTH and NO from PBLs during pregnancy, and it implies a new role for ACTH and NO secreted from PBLs in recognition and, probably, maintenance of pregnancy.

Circadian and pulsatile variations in plasma levels of inhibin, FSH, LH and testosterone in adult Murrah buffalo bulls.

The present study investigated pulsatile and circadian variations in the circulatory levels of inhibin, gonadotrophins and testosterone. Six adult buffalo bulls (6 to 7 yr of age) were fitted with indwelling jugular vein catheters, and blood samples were collected at 2-h intervals for a period of 24 h and then at 15-min interval for 5 h. Plasma concentrations of inhibin, FSH, LH and testosterone were determined by specific radioimmunoassays. Plasma inhibin levels in Murrah buffalo bulls ranged between 0.201 to 0.429 ng/mL, with a mean of 0.278 +/- 0.023 ng/mL. No inhibin pulses could be detected during the 15-min sampling interval. Plasma FSH levels ranged between 0.95 to 3.61 ng/mL, the mean concentration of FSH over 24 h was 1.66 +/- 0.25 ng/mL. A single FSH pulse was detected in 2 of 6 bulls. The LH levels in peripheral circulation ranged between 0.92 to 9.91 ng/mL, with a mean concentration of 3.33 +/- 1.02 ng/mL. Pulsatility was detected in LH secretion with an average of 0.6 pulses/h. Plasma testosterone levels in 4 buffalo bulls ranged from 0.19 to 2.99 ng/mL, the mean level over 24 h were 1.34 +/- 0.52 ng/mL. Testosterone levels in peripheral circulation followed the LH secretory pattern, with an average of 0.32 pulses/h. The results indicate parallelism in inhibin, FSH and LH, and testosterone secretory pattern. Divergence in LH and FSH secretory patterns in adult buffalo bulls might be due to the presence of appreciable amounts of peripheral inhibin.