Kisspeptin (Kp-10) inhibits in vitro osteogenic differentiation of multipotent mesenchymal stromal cells extracted from the bone marrow of adult rats

Kisspeptin (Kp-10) is a neuropeptide that binds to GPR54 receptors, exerting several functions mainly in the nervous and reproductive systems of the body. However, its effects and mechanisms of action on the skeletal system remain poorly understood. This study evaluated the effects of different concentrations of Kp-10 on in vitro osteogenic differentiation of multipotent mesenchymal stromal cells (MSCs) extracted from the bone marrow (BM) of adult Wistar rats. Two-month-old female rats were euthanized to extract BM from long bones to obtain MSCs. Four experimental groups were established in vitro: a control and Kp-10 at concentrations of 0.01, 0.05 and, 0.1 µg/mL. After induction of osteogenic differentiation, cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyl tetrazolium bromide (MTT) assay, alkaline phosphatase activity, collagen synthesis, percentage of area covered by MSCs/field and mineralized nodules/field, and immunocytochemistry of the GPR54 receptor tests. Furthermore, evaluation of gene transcripts for type I collagen, Runx-2, Bmp-2, bone sialoprotein, osteocalcin and osteopontin was performed using real-time RT-qPCR. It was observed that MSCs expressed GPR54 receptor to which Kp-10 binds during osteogenic differentiation, promoting a negative effect on osteogenic differentiation. This effect was observed at all the Kp-10 concentrations in a concentration-dependent manner, characterized by a decrease in the activity of alkaline phosphatase, collagen synthesis, mineralized nodules, and decreased expression of gene transcripts for type I collagen, osteocalcin, osteopontin, and Runx-2. Thus, Kp-10 inhibits in vitro osteogenic differentiation of MSCs extracted from the BM of adult Wistar rats.

Ingestion of a moderate dose of alcohol enhances physical exercise-induced changes in blood lactate concentration

The consumption of alcoholic beverages influences carbohydrate and lipid metabolism, although it is not yet clear whether metabolism during physical exercise at different intensities is also affected. This was the objective of the present study. Eight young and healthy volunteers performed a treadmill test to identify the running speed corresponding to a lactate concentration of 4 mM (S4mM). At least 48 h later, they were subjected to two experimental trials (non-alcohol or alcohol) in which they performed two 1-km running sessions at the following intensities: 1) S4mM; 2) 15% above S4mM. In both trials, blood lactate, triglycerides, and glucose concentrations were measured before and after exercise. The acute alcohol intake increased triglycerides, but not lactate concentration under resting conditions. Interestingly, alcohol intake enhanced the exercise-induced increase in lactate concentration at the two intensities: S4mM (non-alcohol: 4.2±0.3 mM vs alcohol: 4.8±0.9 mM; P=0.003) and 15% above S4mM trial (P=0.004). When volunteers ingested alcohol, triglycerides concentration remained increased after treadmill running (e.g., at S4mM - at rest; non-alcohol: 0.2±0.5 mM vs alcohol: 1.3±1.3 mM; P=0.048). In contrast, glucose concentration was not modified by either alcohol intake, exercise, or their combination. We concluded that an acute alcohol intake changed lactate and lipid metabolism without affecting blood glucose concentration. In addition, the increase in lactate concentration caused by alcohol was specifically observed when individuals exercised, whereas augmented triglycerides concentration was already observed before exercise and was sustained thereafter.

Dietary administration of a commercial mixed-species probiotic improves growth performance and modulates the intestinal immunity of tilapia, Oreochromis niloticus

The growth performance, immunological status, intestinal morphology and microbiology of tilapia, Oreochromis niloticus, were investigated after dietary administration of the commercial probiotic AquaStar(®) Growout. Tilapia (29.02 ± 0.33 g) were split into five treatments; control (CON), 1.5 g kg(-1) probiotic (PRO-1.5), 3 g kg(-1) probiotic (PRO-3), pulsed probiotic feeding (PRO-PULSE) or an initial probiotic feed followed by control feeding (PRO-INI). After six weeks of experimental feeding, fish fed PRO-3 displayed significantly higher final weight, weight gain and SGR compared to the CON or PRO-INI treatments. Supplementation of the probiotic at this dose induced an up-regulation of intestinal caspase-3, PCNA and HSP70 mRNA levels compared to the CON fed fish. Immuno-modulatory pathways were also affected; significantly higher expression of TLR2, pro-inflammatory genes TNFα and IL-1β, and anti-inflammatory genes IL-10 and TGFβ suggest that the probiotic may potentiate a higher state of mucosal tolerance and immuno-readiness. Histological appraisal revealed significantly higher numbers of intraepithelial leucocytes in the intestine of PRO-3 fed fish compared with treatments CON, PRO-PULSE and PRO-INI but not PRO-1.5. Additionally, fish receiving PRO-3 had a significantly higher abundance of goblet cells in their mid-intestine when compared with fish from all other treatments. Together, these data suggest that continuous provision of AquaStar(®) Growout at 3 g kg(-1) can improve tilapia growth and elevate the intestinal immunological status of the host.

Diets Containing α-Linolenic (ω3) or Oleic (ω9) Fatty Acids Rescues Obese Mice From Insulin Resistance

Subclinical systemic inflammation is a hallmark of obesity and insulin resistance. The results obtained from a number of experimental studies suggest that targeting different components of the inflammatory machinery may result in the improvement of the metabolic phenotype. Unsaturated fatty acids exert antiinflammatory activity through several distinct mechanisms. Here, we tested the capacity of ω3 and ω9 fatty acids, directly from their food matrix, to exert antiinflammatory activity through the G protein-coupled receptor (GPR)120 and GPR40 pathways. GPR120 was activated in liver, skeletal muscle, and adipose tissues, reverting inflammation and insulin resistance in obese mice. Part of this action was also mediated by GPR40 on muscle, as a novel mechanism described. Pair-feeding and immunoneutralization experiments reinforced the pivotal role of GPR120 as a mediator in the response to the nutrients. The improvement in insulin sensitivity in the high-fat substituted diets was associated with a marked reduction in tissue inflammation, decreased macrophage infiltration, and increased IL-10 levels. Furthermore, improved glucose homeostasis was accompanied by the reduced expression of hepatic gluconeogenic enzymes and reduced body mass. Thus, our data indicate that GPR120 and GPR40 play a critical role as mediators of the beneficial effects of dietary unsaturated fatty acids in the context of obesity-induced insulin resistance.

Hypothalamic AMPK activation blocks lipopolysaccharide inhibition of glucose production in mice liver

Endotoxic hypoglycaemia has an important role in the survival rates of septic patients. Previous studies have demonstrated that hypothalamic AMP-activated protein kinase (hyp-AMPK) activity is sufficient to modulate glucose homeostasis. However, the role of hyp-AMPK in hypoglycaemia associated with endotoxemia is unknown. The aims of this study were to examine hyp-AMPK dephosphorylation in lipopolysaccharide (LPS)-treated mice and to determine whether pharmacological hyp-AMPK activation could reduce the effects of endotoxemia on blood glucose levels. LPS-treated mice showed reduced food intake, diminished basal glycemia, increased serum TNF-α and IL-1β levels and increased hypothalamic p-TAK and TLR4/MyD88 association. These effects were accompanied by hyp-AMPK/ACC dephosphorylation. LPS-treated mice also showed diminished liver expression of PEPCK/G6Pase, reduction in p-FOXO1, p-AMPK, p-STAT3 and p-JNK level and glucose production. Pharmacological hyp-AMPK activation blocked the effects of LPS on the hyp-AMPK phosphorylation, liver PEPCK expression and glucose production. Furthermore, the effects of LPS were TLR4-dependent because hyp-AMPK phosphorylation, liver PEPCK expression and fasting glycemia were not affected in TLR4-mutant mice. These results suggest that hyp-AMPK activity may be an important pharmacological target to control glucose homeostasis during endotoxemia.

Utilization of the sex-linked gene for imperfect albinism (S*ALS). 2. Yolk sac lipid utilization

The gene for sex-linked imperfect albinism (S*ALS) has been associated with reduced early growth and slow utilization of the yolk sac contents. Neonatal growth was studied using albino and nonalbino full siblings that were dissected at 2-d intervals from Day 16 of incubation to 7 d after hatch. Fatty acid composition of the yolk, yolk sac membrane, and liver was determined to study neonatal lipid metabolism. At hatch, albinos had similar BW and lower (P < 0.01) liver weights, suggesting reduced lipid transfer from the yolk sac during late incubation. Nonalbinos started gaining weight at 3 d after hatch, 1 d earlier than albino chicks. Albinos had reduced growth (P < 0.01), larger yolk sacs (P < 0.05), and similar (P > 0.05) yolk uptake from hatch to 7 d after hatch. Albino chicks also had lower body temperatures (P < 0.05) at 2, 4, and 6 d after hatch. Albinos had a slower rate of transfer of yolk lipids to the developing embryo in the last 2 d of incubation. The fatty acid composition of the yolk and yolk sac membrane was similar for both genotypes during the last 3 d of incubation, except for the level of stearic acid, which was higher (P < 0.05) for nonalbinos on Day 18 of incubation for both tissues and at 1 d after hatch for the yolk. The fatty acid composition of the livers of albinos and nonalbinos were similar (P > 0.05) during the neonatal period. For both genotypes, the hepatic level of oleic acid increased to Day 20 of incubation, remained constant to 1 d after hatch, and decreased sharply thereafter. The major difference between the genotypes was a slower rate of transfer of yolk lipids to the developing albino embryo in the last 2 d of incubation.

Utilization of the sex-linked gene for imperfect albinism (S*ALS). 1. Effect of early weight loss on chick metabolism

The sex-linked gene for imperfect albinism (S*ALS) has been associated with slow early growth in some trials but not in others. Albino (59) and nonalbino (73) chicks were raised to 3 d of age to study early growth. At 3 d of age, plasma beta-hydroxybutyrate (beta-HBA) levels were measured and the chicks were euthanatized and dissected to measure liver, gall bladder, and yolk sac weights. Fatty acids of the liver and the yolk sac were also analyzed. On average, albino chicks lost weight between hatch and 3 d of age and nonalbinos gained weight (-2.41 vs 0.74 g/d, P < 0.01). At 3 d of age, livers from albinos contained higher (P < 0.01) levels of docosahexaenoic acid than those of nonalbinos, likely reflecting the dependence on yolk sac nutrients of albinos and on dietary lipids of nonalbinos at this time. Albinos had lower body temperatures (P < 0.01), liver weights (P < 0.01) and gall bladder weights (P < 0.05), and heavier yolk sacs (P < 0.01) than did nonalbinos. Plasma levels of beta-HBA were higher (P < 0.01) for albinos than for nonalbinos. At similar body weights, chicks of both genotypes had similar body temperatures, gall bladder weights, and plasma beta-HBA levels. Linear regressions indicated that in albinos weight loss is associated with larger yolk sacs, smaller livers, larger gall bladders, lower body temperatures, and higher levels of beta-HBA. Yolk sac utilization seemed to be correlated with activation of the digestive system. The inability of starving chicks to use the yolk sac nutrients while lipolysis is taking place suggests that yolk sac absorption does not respond to lipolytic hormones. Because under certain conditions a large proportion of albinos (90% in this experiment) show the symptoms of the starve-out syndrome, the S*ALS gene could serve as a model for the study of this syndrome.

A method for separating sex-linked imperfect albino (S*ALS) and nonalbino embryos before hatch

The feasibility of using the sex-linked gene for imperfect albinism (S*ALS) to sex chicks during incubation by candling was studied. With this technique, the dark eye of nonalbino embryos can be positively identified. Two trials were performed. In a first trial, 66.5 and 89.5% of the 254 nonalbino and 210 albino chicks produced in four hatches were correctly identified by candling at 7 d of incubation. Of 191 eggs predicted to be nonalbinos, 22 were albinos, resulting in an overall accuracy of 88.5% for identification of nonalbino embryos. In a second trial, the accuracy of the technique from 7 to 10 d of incubation was evaluated. Increased age resulted in a tendency for lower accuracy, but candling at 8, 9, or 10 d of incubation allowed identification of a greater (P < 0.05) proportion of the nonalbino population than at 7 d of incubation. Candling at 8 d of incubation allowed identification of nonalbinos and albinos with an accuracy of 81.3 and 84.9%, respectively, suggesting that the ALS gene could be used to sex chicks during incubation when used in a sex-linked cross. This technique may prove advantageous to the laying industry because of savings of incubator and hatcher space. The males of commercial layer lines are normally killed at hatch. Reducing the number that hatch by eliminating them before 10 d of incubation could diminish animal welfare concerns.

IR studies on carrageenan of Ahnfeltia concinna, a marine red alga

The principal polysaccharide of Ahnfeltia concinna gave IR absorptions at 1240, 930, 845-850, and 805 cm-1, all typical of a carrageenan. The polysaccharide was separated into soluble and insoluble fractions with potassium chloride.