Visfatin Protein Levels Research Articles

Low‐Dose Dihydrotestosterone Lowers Lipogenic Master Regulator in Liver and Adipose Tissue from Female Mice

Polycystic Ovarian Syndrome (PCOS) is the leading cause of infertility among women caused by high androgen levels and affects 1 in 10 women. Due to the premature use of hormonal birth control, a large population of women are unaware they have symptoms of PCOS. Non‐Alcoholic Fatty Liver Disease is a continuum of inflammation that limits the livers ability to function properly.Lean hyperandrogenic (HA) women who are diagnosed with PCOS have been associated to also have insulin resistance (IR) and Non‐Alcoholic Fatty Liver Disease (NAFLD). We hypothesized that low dose (dihydrotestosterone) DHT would interrupt hepatic lipid metabolism leading to NAFLD. Proving that the HA and HFD induced insulin resistance pathways are connected would be beneficial for the lives of women with Type 2 Diabetes and PCOS, as it could aid in early screening and detection for NAFLD.We used a low dose DHT animal model to induce the PCOS symptoms onto the mice. Protein concentration assay was run on the liver, adipose, and skeletal muscle tissues using bicinchoninic acid (BCA) protein assay. Proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and transferred to nitrocellulose membranes to be prepared for Western blot analysis. They were blocked then incubated with primary antibodies (SREBP1, SREBP2, p‐ACC, ACC, and FAS; 1:1000 dilution), using GAPDH as a loading control. After incubation with secondary antibodies (goat anti‐mouse IgG; 1:5000 dilution), enhanced chemiluminescence was used for detection of proteins. Densities were quantified using myImageAnalysis software and analyzed by two‐tailed t‐tests with Prism software.The increased hepatic lipid content of DHT mice signifies that the low dose DHT causes NAFLD. Low dose DHT mice displayed decreased inactive and active forms of cytosolic SREBP1c and increased levels of FAS. Inactive and active forms of SREBP2 and p‐ACC levels were the same in control and DHT mice. Low dose DHT lowered the active form of SREBP1c but not the inactive form in WAT compared to controls. In comparison to the controls, p‐ACC was decreased in low dose DHT mice. FAS and the inactive and active form of SREBP2 were unaltered in low dose DHT mice compared to controls. ChREBP protein levels were not readily detected and unchanged in WAT tissue of low dose DHT mice compared to controls. ASCVL1 (FATP2) protein expression was increased in WAT of low dose DHT mice. PPARy was unchanged in WAT of low dose DHT mice compared to controls. FXR protein levels were trending towards being increased but were not significantly different in WAT of low dose DHT mice compared to controls. Visfatin protein levels were not readily detected or altered in WAT tissue of low dose DHT mice compared to controls.Overall, the findings suggest that low‐dose DHT is causing the translocation of SREBP‐1 from the cytosol into the nucleus leading to increased lipogenic gene expression. Low‐dose DHT does not affect overall lipogenic gene expression in skeletal muscle of female mice. Future studies may focus on nuclear extraction to isolate key nuclear proteins (SREBP‐1, SREBP‐2) in order to see whether they are translocated to the nucleus.Support or Funding InformationFunded by the APS STRIDE Fellowship and Howard University Faculty Start up funds. Preliminary data collection and analysis completed by Tina Seidu, Patrick McWhorter, Rabita Alamgir, and Dilip Bogle.Low‐dose DHT (a mouse model of lean PCOS) caused NAFLD.Figure 1

Effects of Diet-Induced Obesity on Tracheal Responsiveness to Methacholine, Tracheal Visfatin Level, and Lung Histological Changes in Ovalbumin-Sensitized Female Wistar Rats.

Many studies have shown a close relationship between obesity and asthma severity. In the present study, the effects of diet-induced obesity were examined on airway responsiveness to methacholine in addition to visfatin level in female Wistar rats' tracheae after sensitization with ovalbumin. The rats were divided into four groups: control with normal diet (ND), ovalbumin (OVA)-sensitized with normal diet (S + ND), high-fat diet (HFD), and OVA-sensitized with a high-fat diet (S + HFD). The animals were fed for 8weeks with standard pelts or high-fat diet and then sensitized and challenged with OVA or saline for another 4weeks. At the end of the study, the tracheae were isolated and assessed for airway responsiveness and visfatin protein levels. Diet-induced obesity groups developed increased weight and obesity indices (p < 0.001). After sensitization with OVA and diet-induced obesity, there were marked leftward shifts in methacholine concentration-response curves in S + HFD group compared to other groups. Also, maximum response was the highest (p < 0.05 to p < 0.001), EC50 was the lowest (p < 0.05 to p < 0.001), and visfatin protein level was the highest (p < 0.05 to p < 0.01) in S + HFD. According to results, diet-induced obesity caused airway hyperresponsiveness to methacholine and enhanced visfatin protein levels in the tracheae of ovalbumin-sensitized female rats. Our results suggested that, in obese ovalbumin-sensitized conditions in female rats, the local production of adipocytokines, such as visfatin, may be increased, resulting in the deterioration of inflammation in lungs. This finding shows a possible mechanism for the altered phenotype in obesity-ovalbumin sensitization conditions in female rats.

FK866 attenuates acute renal injury induced by intestinal ischemia reperfusion in mice

Objective To determine whether administration of FK866, a competitive inhibitor of visfatin, attenuates acute renal injury induced by intestinal ischemia reperfusion (I/R) in mice. Methods Twenty-four male C57BL/6J mice were randomly divided into three groups (n=8): Sham group, I/R group and FK866+ I/R group. FK866 (10 mg/kg) was given intraperitoneally in mice 30 min prior to ischemia in FK866+ I/R group. A intestinal I/R injury model was established by clamping superior mesenteric artery for 90 min, followed by 4-h reperfusion. The histological changes of intestinal and renal tissues were examined. Serum urea nitrogen (BUN) and creatinine (Cr) levels were measured. Serum levels of visfatin, tumor necrosis factor (TNF)-α and interleukin (IL)-6 were measured by enzyme linked immunosorbent assay (ELISA). The mRNA expression of TNF-α and IL-6 was detected by real-time quantitative polymerase chain reaction (Real-time PCR). The protein expression of visfatin, cleaved Caspase-3, cytoplasmic IκBα and nuclear NF-κB was examined by Western blotting. Renal tubular cell apoptosis was determined by TdT-mediated dUTP nick end labeling (TUNEL) technique. Results Renal and serum visfatin protein levels were significantly increased after intestinal I/R compared to those in sham group (0.79±0.23 vs. 0.41±0.12; 120.79±37.45 vs. 82.61±18.17, P<0.01). As compared with the Sham group, the pathological scores of small intestinal mucosa and renal tubular injury in I/R injury group were significantly increased (4.35±0.74 vs. 0.12±0.35; 154.61±42.74 vs. 13.46±2.53, P<0.01). Serum levels of BUN and Cr were significantly increased in the I/R group [(20.62±5.14) mmol/L vs. (8.67±2.75) mmol/L; (40.25±8.91) μmol/L vs. (24.62±5.14) μmol/L, P<0.01]. Both serum TNF-α and IL-6 [(214.94±42.72) pg/L vs. (32.62±8.51) pg/L; (3.45±0.91) ng/L vs. (0.21±0.12) ng/L] and renal TNF-α and IL-6 mRNA levels (12.75±4.87 vs. 1.00±0.16; 51.28±7.68 vs. 1.00±0.21) were significantly increased in the I/R group (P<0.01). I/R significantly resulted in a decrease of IκBα in the cytoplasm (0.79±0.13 vs. 0.23±0.03, P<0.01) and an increase of NF-κB in the nucleus (0.12±0.03 vs. 1.22±0.23, P<0.01). Furthermore, I/R significantly increased cellular apoptosis as indicated by higher levels of apoptotic cells (13.26±3.74 vs. 3.35±1.13, P<0.01) and cleaved Caspase-3 protein (0.69±0.12 vs. 0.25±0.01, P<0.01). In contrast, FK866 treatment significantly attenuated intestinal and renal injury, inhibited proinflammatory cytokine production, cellular apoptosis, and NF-κB activation (P<0.01). Conclusion These findings suggest that FK866 acts as a novel therapeutic compound for intestinal I/R-induced acute renal injury via the inhibition of inflammation and cellular apoptosis. Key words: Visfatin; FK866; Acute renal injury; Intestinal ischemia; Reperfusion injury; Inflammation

FK866, a Visfatin Inhibitor, Protects Against Acute Lung Injury After Intestinal Ischemia–Reperfusion in Mice via NF-κB Pathway

To determine whether administration of FK866, a competitive inhibitor of visfatin, attenuates acute lung injury induced by intestinal ischemia-reperfusion (I/R). Acute lung injury, a frequent complication of intestinal I/R, is an inflammatory disorder of the lung, which is characterized by an overproduction of proinflammatory cytokines and increased permeability of the alveolar-capillary barrier, resulting in multiple organ dysfunction. Therefore, the development of novel and effective therapies for intestinal I/R is critical for the improvement of patient outcome. Visfatin, a 54-kDa secretory protein, is known as a proinflammatory cytokine and plays a deleterious role in inflammatory diseases. Male C57BL/6J mice were subjected to intestinal I/R induced by occlusion of the superior mesenteric artery for 90 minutes, followed by reperfusion. During reperfusion period, mice were treated with vehicle or FK866 (10 mg/kg of body weight) by an intraperitoneal injection. The levels of visfatin, proinflammatory mediators, and other markers were assessed 4 hours after reperfusion. In addition, survival study was conducted in intestinal I/R mice with or without FK866 treatment. Plasma and lung visfatin protein levels were significantly increased after intestinal I/R. FK866 treatment significantly attenuated intestinal and lung injury by inhibiting proinflammatory cytokine production, cellular apoptosis, and NF-κB activation, hence improving survival rate. In vitro studies showed that macrophages treated with lipopolysaccharides upregulated visfatin expression, whereas FK866 inhibited proinflammatory cytokine production via modulation of the NF-κB pathway. Collectively, these findings implicate FK866 as a novel therapeutic compound for intestinal I/R-induced attenuates acute lung injury via modulation of innate immune functions.

Increased Visfatin Messenger Ribonucleic Acid and Protein Levels in Adipose Tissue and Adipocytes in Women with Polycystic Ovary Syndrome: Parallel Increase in Plasma Visfatin

Polycystic ovary syndrome (PCOS) is a multifaceted metabolic disease linked with insulin resistance (IR) and obesity. Recent studies have shown that plasma levels of the insulin-mimetic adipokine visfatin increase with obesity. Currently, no data exist on the relative expression of visfatin in either plasma or adipose tissue of PCOS women. We investigated the mRNA expression of visfatin from sc and omental (om) adipose tissue and sc adipocytes in women with PCOS compared with matched normal women, as well as visfatin protein in adipose tissue; plasma visfatin was also assessed. Real-time RT-PCR and Western blotting were used to assess the relative mRNA and protein expression of visfatin. Biochemical measurements were performed. There was significant up-regulation of visfatin mRNA in both sc (P < 0.05) and om (P < 0.05) adipose tissue of PCOS women, when compared with normal controls; these findings were also reflected in isolated sc adipocytes (PCOS > controls; P < 0.05). In addition to elevated plasma visfatin levels in women with PCOS (mean +/- sd, 30.2 +/- 10.4 vs. 11.2 +/- 6.2 ng/ml; P < 0.01) when compared with normal controls, visfatin protein levels were significantly greater in both sc and om adipose tissue of PCOS women (P < 0.05 and P < 0.01, respectively). The precise reason for the up-regulation of visfatin seen in women with PCOS, a proinflammatory state, is unknown. Additional studies are needed to clarify the potential role of visfatin in the pathophysiology of PCOS.