Characterization of Wnt1-inducible Signaling Pathway Protein-1 in Obese Children and Adolescents.

Wnt1-inducible signaling pathway protein-1 (WISP1), a member of the CCN family, is increasingly being recognized as a potential target for obesity and type 2 diabetes mellitus. Recent studies have shown that WISP1 can regulate low-grade inflammation in obese mice, and circulating WISP1 levels are associated with obesity and type 2 diabetes mellitus in adults. Herein, we measured serum WISP1 levels in obese youth and explored its relationships with pro-inflammatory cytokine interleukin 18 (IL-18) and other metabolic indexes. Totally, 44 normal-weight and 44 obese children and adolescents were enrolled. Physical and laboratory data were recorded, and then serum levels of WISP1 and IL-18 were determined by enzyme-linked immunosorbent assays. Results showed that serum levels of WISP1 were significantly higher in obese children and adolescents than in normal-weight healthy controls (1735.44±15.29 vs. 1364.08±18.69 pg/mL). WISP1 levels were significantly positively correlated with body mass index (BMI) and BMI z-score (r=0.392, P=0.008; r=0.474, P=0.001, respectively) in obese group; circulating IL-18 was increased in obese individuals (1229.06±29.42 vs. 295.87±13.30 pg/mL). Circulating WISP1 levels were significantly correlated with IL-18 (r=0.542, P<0.001), adiponectin (r=0.585, P<0.001) and leptin (r=0.592, P<0.001). The multivariate stepwise regression analysis showed that higher IL-18 levels represented the main determinant of increased WISP1 levels after adjusting for BMI, waist circumference, fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR) and HbA1c in obese individuals (ß=0.542, P=0.000). WISP1 can be involved in glucose/lipid metabolism in obese youth, which may be modulated by IL-18. Increased WISP1 levels may be a risk factor of obesity and insulin resistance, and WISP1 has a potential therapeutic effect on insulin resistance in obese children and adolescents.

Glucagon-like peptide 1 based therapy for type 2 diabetes.

BACKGROUND: Incidence of type 2 diabetes mellitus (T2DM) has increased in young people in recent years and new therapies are required for its effective treatment. Glucagon-like peptide 1 (GLP-1) is a potent blood glucose-lowering hormone produced in the L cells of the intestine. It may be potentially effective in the treatment of hyperglycemia in patients with T2DM. DATA SOURCES: PubMed database were searched with the terms "GLP-1", "incretins" and "diabetes". RESULTS: GLP-1 is a product of the glucagon gene, and its secretion is controlled by both neural and endocrine signals. GLP-1 lowers plasma glucose by stimulating insulin and suppressing secretion of glucagons, thus inhibiting gastric emptying and reducing appetite. GLP-1 exerts these actions by the engagement of structurally distinct G-protein-coupled receptors (GPCRs). In patients with T2DM, GLP-1 increases insulin secretion and normalizes both fasting and postprandial blood glucose when given as a continuous intravenous infusion. However, the native hormone is unsuitable as a drug because it is broken down rapidly by dipeptidyl peptidase IV (DPP-4) and cleared by the kidneys. Fortunately, many GLP-1 agonists or analogues and DPP-4 inhibitors have been found or developed, such as exendin-4, exenatide, liraglutide, CJC1131, vidaliptin and P32/98. Clinical trials have shown their therapeutic functions in T2DM with little adverse reaction. CONCLUSION: A GLP-1 based therapy will be safe and effective for the treatment of T2DM.

[Pathogenesis of retinal neovascularization in a rat model of oxygen fluctuations-induced retinopathy].

OBJECTIVE: Fluctuations in arterial oxygen are associated with development of severe retinopathy of prematurity (ROP) in humans. However, the causal relationship between oxygen variability and ROP remains unknown. The authors developed a rat model of retinal neovascularization by repeated fluctuations of inhaled oxygen between hypoxia and hyperoxia to investigate the mechanism of the development of retinal neovascularization, the regulation of vascular endothelial growth factor (VEGF) and KDR/Flk-1 (VEGFR-2) expression. METHODS: Two hundred and eight newborn Sprague Dawley rats were randomly divided into oxygen and air groups. The oxygen concentration in the oxygen group was alternated between 50% and 10% every 24 hours for 14 days. The control group were kept in room air environment. VEGF and Flk-1 expression was observed at 14, 18 and 25 days after birth in both exposed group and control group by immunohistochemical staining and semiquantitative RT-PCR. The status of retinal vasculature on day 4 after oxygen exposure was also observed. The retinas were dissected and stained by using a histochemical method for detecting adenosine diphosphatase (ADPase) activity, digital images of the retinas were captured and the peripheral avascular retina were measured. HE staining on methacrylate sections of eyes was used for counting the number of nuclei extending from retinal area into vitreous to identify extraretinal neovascularization. Numeric data were expressed as the mean +/- standard deviation (SD). Statistical calculations were performed using the SAS 8.1 statistical package. Differences in measured variables between experimental and control groups were determined using comparison of the means using two-way analysis of variance (ANOVA) statistical calculations and T-test. AP value less than 0.05 was regarded as significant. RESULTS: (1) The animal model was successfully established: the avascular areas of retina of 18-day-old rats were larger than those of the control group and the numbers of nuclei extending from retinal area into vitreous in exposed group were significantly higher compared to the control (P < 0.05). (2) The expression of VEGF and Flk-1 on the 14(th) day in the oxygen group was significantly stronger than that of the control group (P < 0.05). In the oxygen group, VEGF and Flk-1 expression was the strongest in the retina on the 18(th) day, the result had significant difference as compared with the 14(th) and 25(th) day (P < 0.05), and they were also stronger than that of the control group (P < 0.05). The expression of VEGF and Flk-1 decreased on the 25(th) day and had no significant difference as compared with the control group (P > 0.05). (3) Both VEGF-mRNA and Flk-1-mRNA significantly increased on the 14(th) day and the 18th day (P < 0.05). On the 25(th) day, the amounts of VEGF-mRNA and Flk-1-mRNA were similar between the control and oxygen group (P > 0.05). CONCLUSION: Fluctuation in oxygen is associated with the development of retinal neovascularization in the retinopathy. Increased expressions of VEGF and Flk-1 in the oxgen fluctuations-induced neovascularized retina suggested that VEGF and Flk-1 might play a critical role in the pathogenesis of ROP. The results also indicated the positive feedback in the pathogenesis of ROP that the synergistic interaction of VEGF and Flk-1 in the retinal vascular proliferation. These findings provide insight into the effect of repeated oxygen fluctuation on the development of severe ROP in preterm infants.