Visfatin relieves myocardial ischemia-reperfusion injury through activation of PI3K/Akt/HSP70 signaling axis.

OBJECTIVE: Myocardial ischemia-reperfusion injury (MIRI) is the most common complication of ischemic cardiomyopathy, which severely affects the prognosis of patients. The purpose of this study was to investigate the protective effects of visfatin on the myocardium after ischemia-reperfusion (I/R) and its mechanism. MATERIALS AND METHODS: Sprague Dawley rats were used to construct the MIRI model and visfatin was administrated intraperitoneally in rats to determine the protective effect of visfatin on myocardium after I/R. In addition, visfatin was used to treat rat myocardial cell line H9c2 cells and detect its effect on H9c2 cells. The effect of visfatin on the PI3K/Akt/HSP70 signaling axis in H9c2 cells was also detected to determine the mechanism of the myocardial protection of visfatin. RESULTS: The damage of cardiomyocytes in MIRI rats pretreated with visfatin was significantly improved compared with untreated MIRI rats. Visfatin also reduced the level of inflammation and apoptosis of cardiomyocytes in MIRI rats, reduced myocardial injury markers, and improved cardiac function. In vitro, visfatin also reduced inflammatory and apoptotic factors in H9c2 cells. In addition, visfatin also promoted the activity of the PI3K/Akt signaling pathway and increased HSP70 expression in H9c2 cells. The inhibition of the PI3K/Akt signaling pathway was found to attenuate the promotion of HSP70 by visfatin. SiRNA-HSP70 also attenuated the protective effect of visfatin on H9c2 cells. CONCLUSIONS: Visfatin reduces the inflammation and apoptosis levels of myocardial cells through the PI3K/Akt/HSP70 signaling axis, thereby reducing I/R-induced myocardial injury.

Intracerebroventricular Delivery of Recombinant NAMPT Deters Inflammation and Protects Against Cerebral Ischemia.

Our previous study indicated that nicotinamide phosphoribosyltransferase (NAMPT) is released from cells and might be an important extracellular neuroprotective factor in brain ischemia. Here, we tested whether NAMPT protects against ischemic brain injury when administered directly into the intracerebroventricular (ICV) compartment of the cranium. Recombinant NAMPT protein (2 µg) was delivered ICV in mice subjected to 45-min middle cerebral artery occlusion (MCAO), and the effects on infarct volume, sensorimotor function, microglia/macrophage polarization, neutrophil infiltration, and BBB integrity were analyzed. The results indicate that ICV administration of NAMPT significantly reduced infarct volume, retained its beneficial properties even when ICV administration was delayed by 6 h after MCAO, and improved neurological outcomes. NAMPT treatment inhibited pro-inflammatory microglia/macrophages, promoted microglia/macrophage polarization toward the anti-inflammatory phenotype, and reduced the infiltration of neutrophils into the perilesional area after brain ischemia. In vitro studies indicated that multiple pro-inflammatory microglial markers/cytokines were downregulated while multiple anti-inflammatory microglial markers/cytokines were induced in primary microglial cultures treated with NAMPT protein. NAMPT treatment also fortified the blood-brain barrier (BBB), as shown by reduced extravascular leakage of the small-molecule tracer Alexa Fluor 555 Cadaverine and larger-sized endogenous IgGs into brain parenchyma. Thus, NAMPT may protect against ischemic brain injury partly through a novel anti-inflammatory mechanism, which in turn maintains BBB integrity and reduces the infiltration of peripheral inflammatory cells. Taken together, these results provide validation of recombinant NAMPT delivery into the extracellular space as a potential neuroprotective strategy for stroke.

Comparative transcriptome analysis of hypothalamus-regulated feed intake induced by exogenous visfatin in chicks.

BACKGROUND: The intracerebroventricular injection of visfatin increases feed intake. However, little is known about the molecular mechanism in chicks. This study was conducted to assess the effect of visfatin on the feeding behavior of chicks and the associated molecular mechanism. RESULTS: In response to the intraventricular injection of 40 ng and 400 ng visfatin, feed intake in chicks was significantly increased, and the concentrations of glucose, insulin, TG, HDL and LDL were significantly altered. Using RNA-seq, we identified DEGs in the chick hypothalamus at 60 min after injection with various doses of visfatin. In total, 325, 85 and 519 DEGs were identified in the treated chick hypothalamus in the LT vs C, HT vs C and LT vs HT comparisons, respectively. The changes in the expression profiles of DEGs, GO functional categories, KEGG pathways, and PPI networks by visfatin-mediated regulation of feed intake were analyzed. The DEGs were grouped into 8 clusters based on their expression patterns via K-mean clustering; there were 14 appetite-related DEGs enriched in the hormone activity GO term. The neuroactive ligand-receptor interaction pathway was the key pathway affected by visfatin. The PPI analysis of DEGs showed that POMC was a hub gene that interacted with the maximum number of nodes and ingestion-related pathways, including POMC, CRH, AgRP, NPY, TRH, VIP, NPYL, CGA and TSHB. CONCLUSION: These common DEGs were enriched in the hormone activity GO term and the neuroactive ligand-receptor interaction pathway. Therefore, visfatin causes hyperphagia via the POMC/CRH and NPY/AgRP signaling pathways. These results provide valuable information about the molecular mechanisms of the regulation of food intake by visfatin.

Synergistic Effects of Resistin and Visfatin as Adipocyte Derived Hormones on Telomerase Gene Expression in AGS Gastric Cancer Cell Line.

Recently suggested that adipocytokines may play a role in pathogenesis and progression of certain cancers, especially in gastric cancer. The previous study showed Resistin and Visfatin, as adipocyte derived hormones, separately increases telomerase (hTERT) gene, the aim of this study is investigating synergic effects of Resistin and Visfatin on telomerase gene expression, in AGS gastric cancer cell line. In this study, human gastric cancer AGS cell line was selected. After stimulation with increasing concentrations of Resistin and Visfatin recombinant proteins for 24 and 48 hours, cell proliferation was assessed by XTT assay. In order to investigate the telomerase gene expression affected by these proteins, total RNA was extracted, cDNA was synthesized, and expression of hTERT mRNA was carried out by real-time reverse transcription polymerase chain reaction. After Resistin and Visfatin, recombinant proteins treatment was increased the gastric cell line proliferation and expression of Human Telomerase Reverse Transcriptase (hTERT), but co-stimulation with Resistin and Visfatin showed greater inducible effects on cell proliferation and telomerase gene expression in comparison with the stimulatory effect of the individual hormone. This study has shown Resistin, and Visfatin synergistically increased gastric cancer cell proliferation and enhanced the telomerase gene expression. These data showed that these two hormones in gastric cancer tissue could cooperatively accelerate cancer cell growth via enhancing the telomerase expression as a cancer gene.

HIF-1α mediates visfatin-induced CTGF expression in vascular endothelial cells.

Visfatin is an adipokine that functions as a mediator of endothelial dysfunction and cardiovascular diseases. Connective tissue growth factor (CTGF) is a key factor in vascular remodeling and atherosclerosis. However, the association between visfatin and CTGF is unclear. Therefore the study was to test the hypothesis that visfatin could modulate the expression of CTGF in vascular endothelial cells. In our study, cultured endothelial cell line EA.Hy926 cells were treated with different concentrations of visfatin for different times. The CTGF gene expression was analyzed by real-time PCR, and the protein expression of CTGF was assessed by Western Blot. The results showed that 100ng/mL concentration of visfatin could induce CTGF mRNA expression after 6 hours treatment, which peaked at 24 hours. And 100ng/mL concentration of visfatin also increased CTGF protein production after 12 hours treatment in EA.Hy926 cells. The expression of transforming growth factor-ß1 (TGF-ß1) mRNA was almost unaffected in cells treated with visfatin, whereas the expression of hypoxia inducible factor-1α (HIF-1α) was increased significantly. Moreover, knockdown of HIF-1α by its specific shRNA inhibits the effect of visfatin on CTGF expression. In conclusion, the up-regulation of CTGF expression by visfatin might be mediated via HIF-1α -dependent pathway, but not the TGF-ß1 pathway in EA.Hy926 cells.

Involvement of TRPC1 in Nampt-induced cardiomyocyte hypertrophy through the activation of ER stress.

Nicotinamide phosphoribosyltransferase (Nampt) is involved in the development of cardiac hypertrophy. Transient receptor potential canonical channel 1 (TRPC1) and endoplasmic reticulum stress (ER stress) are regarded as critical pathways in cardiac hypertrophy. Therefore, we hypothesizedthat TRPC1 might be associated with ER stress in Nampt-induced cardiac hypertrophy. CulturedH9c2cardiomyocyteswereexposed to Namptfor different timesand the expression of markers of cardiomyocyte hypertrophy and ER stress, as well as TRPC1 were detected. Moreover, specific TRPC1-shRNA (short hairpin RNA) expressing plasmid was transfected to knockdown TRPC1 expression before Nampt stimulation. Thapsigargin was used as an agonist and pravastatin was employed as an inhibitor of ER stress. The results demonstrated that exposure of H9c2 cells to 100 ng/mL Nampt for 24h, 48h or 72h significantly increased the expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), markers of ER stress and TRPC1. The Nampt-induced expression of TRPC1 was attenuated by pre-treatment with pravastatin, whereas promoted by pre-treatment with thapsigargin. Furthermore, transfection of TRPC1-shRNA for 48h partially inhibited Nampt-induced expression of ER stress markers and BNP in H9c2 cells. Our data suggest that TRPC1 might play an important role in cardiomyocyte hypertrophy induced by Namptinan ER stress-dependent way.

Nicotinamide Phosphoribosyltransferase Promotes Pulmonary Vascular Remodeling and Is a Therapeutic Target in Pulmonary Arterial Hypertension.

BACKGROUND: Pulmonary arterial hypertension is a severe and progressive disease, a hallmark of which is pulmonary vascular remodeling. Nicotinamide phosphoribosyltransferase (NAMPT) is a cytozyme that regulates intracellular nicotinamide adenine dinucleotide levels and cellular redox state, regulates histone deacetylases, promotes cell proliferation, and inhibits apoptosis. We hypothesized that NAMPT promotes pulmonary vascular remodeling and that inhibition of NAMPT could attenuate pulmonary hypertension. METHODS: Plasma, mRNA, and protein levels of NAMPT were measured in the lungs and isolated pulmonary artery endothelial cells from patients with pulmonary arterial hypertension and in the lungs of rodent models of pulmonary hypertension. Nampt+/- mice were exposed to 10% hypoxia and room air for 4 weeks, and the preventive and therapeutic effects of NAMPT inhibition were tested in the monocrotaline and Sugen hypoxia models of pulmonary hypertension. The effects of NAMPT activity on proliferation, migration, apoptosis, and calcium signaling were tested in human pulmonary artery smooth muscle cells. RESULTS: Plasma and mRNA and protein levels of NAMPT were increased in the lungs and isolated pulmonary artery endothelial cells from patients with pulmonary arterial hypertension, as well as in lungs of rodent models of pulmonary hypertension. Nampt+/- mice were protected from hypoxia-mediated pulmonary hypertension. NAMPT activity promoted human pulmonary artery smooth muscle cell proliferation via a paracrine effect. In addition, recombinant NAMPT stimulated human pulmonary artery smooth muscle cell proliferation via enhancement of store-operated calcium entry by enhancing expression of Orai2 and STIM2. Last, inhibition of NAMPT activity attenuated monocrotaline and Sugen hypoxia-induced pulmonary hypertension in rats. CONCLUSIONS: Our data provide evidence that NAMPT plays a role in pulmonary vascular remodeling and that its inhibition could be a potential therapeutic target for pulmonary arterial hypertension.

Visfatin Triggers Anorexia and Body Weight Loss through Regulating the Inflammatory Response in the Hypothalamic Microglia.

Visfatin is an adipokine that is secreted from adipose tissue, and it is involved in a variety of physiological processes. In particular, visfatin has been implicated in metabolic diseases, such as obesity and type 2 diabetes, which are directly linked to systemic inflammation. However, the potential impacts of visfatin on the hypothalamic control of energy homeostasis, which is involved in microglial inflammation, have not fully been investigated. In this study, we found that treatment with exogenous recombinant visfatin protein led to the activation of the inflammatory response in a microglial cell line. In addition, we observed that central administration of visfatin led to the activation of microglia in the hypothalamus. Finally, we found that visfatin reduced food intake and body weight through activating POMC neurons in association with microglia activation in mice. These findings indicate that elevation of central visfatin levels may be associated with homeostatic feeding behavior in response to metabolic shifts, such as increased adiposity following inflammatory processes in the hypothalamus.

Effect of visfatin on the structure and immune levels in the small intestine of LPS-induced rats / Efecto de la visfatina sobre la estructura y los niveles de inmunidad en el intestino delgado de ratas inducidas por lipopolisacáridos

This study investigated the effects of visfatin on the structure and the immunity levels in the small intestine of LPS-induced rats. Forty Wistar male and female SPF rats were randomly and equally divided into four groups: the saline (control), vistfatin, lipopolysaccharide (LPS), and visfatin+LPS co-stimulated. The functions of visfatin in the intestinal mucosal immunity were investigated by examining the variation of tissue structure, inflammation and immunity-related proteins in the intestine of immunologically stressed rats using HE staining, ELISA, immunohistochemistry and Western Blot. The results showed that, when compared with the control group, the visfatin-treated group showed a decrease in the intestinal villus height and width, and a significant increase in the levels of IL-6 and TNF-ð as well as Immunoglobulin A (IgA) positive cells. Additionally, when compared with the LPS-treated group, the visfatin+LPS co-stimulated group showed a decrease in the villus height and width as well as the levels of IL-6 and TNF-ð, and an increase in IgA levels, implying a shrinking response to LPS injection. All the results suggest that, under normal physiological conditions, visfatin disturbs the body's homeostasis and causes intestinal villus atrophy by increasing IgA expression. While under immune response conditions, LPS acts as an exogenous antigen to promote visfatin against LPS-induced inflammation by decreasing the expression of IgA. Under immune stress conditions, visfatin as an exogenous stimulus promotes the immune response by regulating the protein levels of IL-6, TNF-ð and IgA.

Este estudio investigó los efectos de la visfatina sobre la estructura y los niveles de inmunidad en el intestino delgado de ratas inducidas por lipopolisacáridos (LPS). Cuarenta ratas Wistar se dividieron aleatoriamente e igualmente en cuatro grupos: solución salina (control), vistafin, LPS y visfatina + LPS co-estimuladas. Las funciones de la visfatina en la inmunidad de la mucosa intestinal se investigaron mediante el examen de variación de la estructura del tejido, la inflamación y las proteínas relacionadas con la inmunidad en el intestino de ratas estresadas inmunológicamente; usando tinción HE, ELISA, inmunohistoquímica y Western Blot. Los resultados mostraron que, en comparación con el grupo control, el grupo tratado con visfatina presentó una disminución en la altura y ancho de las vellosidades intestinales, y un aumento significativo en los niveles de IL-6 y TNF-ð, así como inmunoglobulina A (IgA células positivas). Además, al comparar este grupo con el grupo tratado con LPS- el grupo visfatina + LPS co-estimulado mostró una disminución en la altura y ancho de las vellosidades, así como en los niveles de IL-6 y TNF-ð, y un aumento en los niveles de IgA, lo que implica reducción de una respuesta a la inyección LPS. Todos los resultados sugieren que, en condiciones fisiológicas normales, la visfatina perturba la homeostasis del cuerpo y provoca la atrofia de las vellosidades intestinales mediante el aumento de la expresión de IgA. Mientras que bajo condiciones de la respuesta inmune, LPS actúa como un antígeno exógeno para promover visfatina contra la inflamación inducida por LPS por la disminución de la expresión de IgA. En condiciones de estrés inmunológico, la visfatina como estímulo exógeno promueve la respuesta inmune mediante la regulación de los niveles de proteína de IL-6, TNF-ð e IgA.

Visfatin reduces hippocampal CA1 cells death and improves learning and memory deficits after transient global ischemia/reperfusion.

Visfatin is a novel adipocytokine with insulin-mimetic effect which plays a role in glucose-lowering effect of insulin and improves insulin sensitivity. It has been linked to a variety of cellular processes and its plays important roles in cell apoptosis and survival. Moreover, cerebral ischemia causes loss of hippocampus pyramidal cells, therefore, in this study; we investigated the neuroprotective effect of visfatin after global cerebral ischemia in male rats. Both common carotid arteries were occluded for 20 minutes followed by 4 days of reperfusion. Animals were treated with either the Visfatin (intracerebro-ventricular; 100 ng) or saline vehicle (2 µl) at the time of reperfusion. Behavioral examination, apoptosis and necrosis assessment were performed 4 days after ischemia. Visfatin significantly reduced Caspase-3 activation (P < 0.001), TUNEL positive cells (P < 0.05) and necrotic cell death in the CA1 region of the hippocampus (P < 0.001). Moreover, treatment with visfatin significantly improved memory deficits of cerebral ischemia-reperfusion rats (P < 0.05). The results suggest that visfatin via its antiapoptotic properties has significant neuroprotective effects on cerebral ischemia reperfusion injury in rats.

Visfatin induces MUC8 and MUC5B expression via p38 MAPK/ROS/NF-κB in human airway epithelial cells.

BACKGROUND: Among a variety of inflammatory mediators, visfatin is a proinflammatory adipocytokine associated with inflammatory reactions in obesity, metabolic syndrome, chronic inflammatory disease, and autoimmune disease. However, the biological role of visfatin in secretion of major mucins in human airway epithelial cells has not been reported. Therefore, this study was conducted in order to investigate the effect and the brief signaling pathway of visfatin on MUC8 and MUC5B expression in human airway epithelial cells. RESULTS: Visfatin significantly induced MUC8 and MUC5B expression. Visfatin significantly activated phosphorylation of p38 MAPK. Treatment with SB203580 (p38 MAPK inhibitor) and knockdown of p38 MAPK by siRNA significantly blocked visfatin-induced MUC8 and MUC5B expression.Visfatin significantly increased ROS formation. Treatment with SB203580 significantly attenuated visfatin-induced ROS formation. Treatment with NAC (ROS scavenger) and DPI (NADPH oxidase inhibitor) significantly attenuated visfatin-induced MUC8 and MUC5B expression. However, treatment with NAC and DPI did not attenuate visfatin-activated phosphorylation of p38 MAPK. Visfatin significantly activated the phosphorylation of NF-κB. Treatment with PDTC (NF-κB inhibitor) significantly attenuated visfatin-induced MUC8 and MUC5B expression. CONCLUSIONS: These results suggest that visfatin induces MUC8 and MUC5B expression through p38 MAPK/ROS/NF-κB signaling pathway in human airway epithelial cells.

The adipokine visfatin induces tissue factor expression in human coronary artery endothelial cells: another piece in the adipokines puzzle.

INTRODUCTION: Adipocytes are nowadays recognized as cells able to produce and secrete a large variety of active substances with direct effects on vascular cells, known as adipokines. Visfatin is a recently identified adipokine not yet completely characterized for its pathophysiological role in cardiovascular disease. Increased levels of visfatin are measurable in the plasma of patients with coronary artery disease and specifically in those with acute coronary syndromes (ACS). Several studies have indicated that Tissue Factor (TF) plays a pivotal role in the pathophysiology of ACS by triggering the formation of intracoronary thrombi following endothelial injury. This study investigates the effects of visfatin on TF in human coronary endothelial cells (HCAECs). METHODS: HCAECs were stimulated with visfatin in a concentration range usually measurable in plasma of patients with ACS and than processed to evaluate TF-mRNA levels as well as TF expression/activity. Finally, the role of NF-κB pathway was investigated. RESULTS: We demonstrate that visfatin induces transcription of mRNA for TF by Real Time PCR. In addition, we show that this adipokine promotes surface expression of TF that is functionally active since we measured increased procoagulant activity. Visfatin effects on TF appear modulated by the activation of the transcription factor, NF-κB, since NF-κB inhibitors suppressed TF expression. Finally, we show that the nicotinamide phopsphoribosyltransferase enzymatic activity of visfatin seems to play a pivotal role in modulating the NF-κB driven regulation of TF. DISCUSSION: Data of the present study, although in vitro, indicate that visfatin, at doses measurable in ACS patient plasma, induces a procoagulant phenotype in human coronary endothelial cells by promoting TF expression. These observations support the hypothesis that this adipokine might play a relevant role as an active partaker in athero-thrombotic disease.

Administration of visfatin during superovulation improves developmental competency of oocytes and fertility potential in aged female mice.

OBJECTIVE: To examine whether visfatin administration during superovulation improves ovarian response, developmental competence of oocytes, and fertility in aged female mice. DESIGN: Controlled experimental study. SETTING: University hospital. ANIMAL(S): Two groups of differently aged C57BL female mice (6-11 and 26-31 weeks). INTERVENTION(S): Female mice were coinjected intraperitoneally with 5 IU pregnant mare's serum gonadotropin (PMSG) and visfatin of various doses (0-500 ng/mL), followed by 5 IU human chorionic gonadotropin (hCG) injection 48 hours later. Then the mice were immediately mated with an individual male. After 18 hours zygotes were cultured, and expression of ovarian visfatin and vascular endothelial growth factor (VEGF) was examined. Potential pregnancies of visfatin-administered aged female mice were monitored for delivery of offspring. MAIN OUTCOME MEASURE(S): Number of zygotes retrieved, embryo developmental competency, fertility potential, ovarian visfatin and VEGF expression. RESULT(S): Ovarian visfatin expression was significantly decreased in the aged mice group compared with the young. Visfatin administration significantly increased embryo developmental rate and ovarian visfatin and VEGF expressions in the aged mice. Visfatin-administered aged mice delivered significantly higher numbers of offspring than controls. CONCLUSION(S): This study suggests that visfatin administration during superovulation plays an important role in regulating oocyte quality and can improve oocyte quality and fertility of aged female mice.

Visfatin induces sickness responses in the brain.

BACKGROUND/OBJECTIVE: Visfatin, also known as nicotiamide phosphoribosyltransferase or pre-B cell colony enhancing factor, is a pro-inflammatory cytokine whose serum level is increased in sepsis and cancer as well as in obesity. Here we report a pro-inflammatory role of visfatin in the brain, to mediate sickness responses including anorexia, hyperthermia and hypoactivity. METHODOLOGY: Rats were intracerebroventricularly (ICV) injected with visfatin, and changes in food intake, body weight, body temperature and locomotor activity were monitored. Real-time PCR was applied to determine the expressions of pro-inflammatory cytokines, proopiomelanocortin (POMC) and prostaglandin-synthesizing enzymes in their brain. To determine the roles of cyclooxygenase (COX) and melanocortin in the visfatin action, rats were ICV-injected with visfatin with or without SHU9119, a melanocortin receptor antagonist, or indomethacin, a COX inhibitor, and their sickness behaviors were evaluated. PRINCIPAL FINDINGS: Administration of visfatin decreased food intake, body weight and locomotor activity and increased body temperature. Visfatin evoked significant increases in the levels of pro-inflammatory cytokines, prostaglandin-synthesizing enzymes and POMC, an anorexigenic neuropeptide. Indomethacin attenuated the effects of visfatin on hyperthermia and hypoactivity, but not anorexia. Further, SHU9119 blocked visfatin-induced anorexia but did not affect hyperthermia or hypoactivity. CONCLUSIONS: Visfatin induced sickness responses via regulation of COX and the melanocortin pathway in the brain.

Visfatin stimulates proliferation of MCF-7 human breast cancer cells.

Obesity, a condition characterized by increased fat content and altered secretion of adipokines, is a risk factor for postmenopausal breast cancer. Visfatin has recently been established as a novel adipokine that is highly enriched in visceral fat. Here we report that visfatin regulated proliferation of MCF-7 human breast cancer cells. Exogenous administration of recombinant visfatin increased cell proliferation and DNA synthesis rate in MCF-7 cells. Furthermore, visfatin activated G1-S phase cell cycle progression by upregulation of cyclin D1 and cdk2 expression. Visfatin also increased the expression of matrix metalloproteinases 2, matrix metalloproteinases 9, and vascular endothelial growth factor genes, suggesting that it may function in metastasis and angiogenesis of breast cancer. Taken together, these findings suggest that visfatin plays an important role in breast cancer progression.

The novel adipocytokine visfatin exerts direct cardioprotective effects.

Visfatin is an adipocytokine capable of mimicking the glucose-lowering effects of insulin and activating the pro-survival kinases phosphatidylinositol-3-OH kinase (PI3K)-protein kinase B (Akt) and mitogen-activated protein kinase kinase 1 and 2 (MEK1/2)-extracellular signal-regulated kinase 1 and 2 (Erk 1/2). Experimental studies have demonstrated that the activation of these kinases confers cardioprotection through the inhibition of the mitochondrial permeability transition pore (mPTP). Whether visfatin is capable of exerting direct cardioprotective effects through these mechanisms is unknown and is the subject of the current study. Anaesthetized C57BL/6 male mice were subjected to in situ 30 min. of regional myocardial ischaemia and 120 min. of reperfusion. The administration of an intravenous bolus of visfatin (5 x 10(-6) micromol) at the time of myocardial reperfusion reduced the myocardial infarct size from 46.1+/-4.1% in control hearts to 27.3+/-4.0% (n>or= 6/group, P<0.05), an effect that was blocked by the PI3K inhibitor, wortmannin, and the MEK1/2 inhibitor, U0126 (48.8+/-5.5% and 45.9+/-8.4%, respectively, versus 27.3+/-4.0% with visfatin; n>or= 6/group, P<0.05). In murine ventricular cardiomyocytes subjected to 30 min. of hypoxia followed by 30 min. of reoxygenation, visfatin (100 ng/ml), administered at the time of reoxygenation, reduced the cell death from 65.2+/-4.6% in control to 49.2+/-3.7%(n>200 cells/group, P<0.05), an effect that was abrogated by wortmannin and U0126 (68.1+/-5.2% and 59.7+/-6.2%, respectively; n>200 cells/group, P>0.05). Finally, the treatment of murine ventricular cardiomyocytes with visfatin (100 ng/ml) delayed the opening of the mPTP induced by oxidative stress from 81.2+/-4 sec. in control to 120+/-7 sec. (n>20 cells/group, P<0.05) in a PI3K- and MEK1/2-dependent manner. We report that the adipocytokine, visfatin, is capable of reducing myocardial injury when administered at the time of myocardial reperfusion in both the in situ murine heart and the isolated murine cardiomyocytes. The mechanism appears to involve the PI3K and MEK1/2 pathways and the mPTP.

Central visfatin causes orexigenic effects in chicks.

Intracerebroventricular injection of visfatin caused increased feed intake and pecking efficiency, but did not affect water intake in chicks. Visfatin-treated chicks had increased c-Fos immunoreactivity in the lateral hypothalamus, decreased reactivity in the ventromedial hypothalamus and the dorsomedial hypothalamus, infundibular nucleus, periventricular nucleus, paraventricular nucleus were not affected. A low dose of visfatin increased locomotion. We conclude that intracerebroventricular injection of visfatin causes orexigenic effects in chicks.