Yoon Jung Choi

Intracerebroventricular Injection of Metformin Induces Anorexia in Rats

Background Metformin, an oral biguanide insulin-sensitizing agent, is well known to decrease appetite. Although there is evidence that metformin could affect the brain directly, the exact mechanism is not yet known. Methods To evaluate whether metformin induces anorexia via the hypothalamus, various concentrations of metformin were injected into the lateral ventricle of rats through a chronically implanted catheter and food intake was measured for 24 hours. The hypothalamic neuropeptides associated with regulation of food intake were also analyzed following 1 hour of intracerebroventricular (ICV) injections of metformin. Results An ICV injection of metformin decreased food intake in a dose-dependent manner in unrestrained conscious rats. Hypothalamic phosphorylated AMP-activated protein kinase (pAMPK) increased by 3 µg with metformin treatment, but there was no further increase in pAMPK with increases in metformin dosage. The hypothalamic phosphorylated signal transducer and activator of transcription 3 (pSTAT3) increased by 3 µg with metformin treatment, but, there was no further increase in pSTAT3 level following increases of metformin dosage. Hypothalamic proopiomelanocortin was elevated with metformin treatment, while neuropeptide Y was not significantly changed. Conclusion Our results suggest that metformin induces anorexia via direct action in the hypothalamus and the increase in pSTAT3, at least in part, is involved in the process. However, hypothalamic pAMPK appears not to contribute to metformin-induced appetite reduction in normal rats. Further studies exploring new pathways connecting metformin and feeding regulation are needed.

The Use Pattern and Clinical Impact of New Antiplatelet Agents Including Prasugrel and Ticagrelor on 30-day Outcomes after Acute Myocardial Infarction in Korea: Korean Health Insurance Review and Assessment Data

Background and Objectives Despite the favorable efficacy of new antiplatelet agents demonstrated in randomized controlled trials, their clinical implications in Korea are unclear. The purpose of this study was to investigate trends in antiplatelet agent use for acute myocardial infarction (AMI) and their impact on 30-day clinical outcomes. Methods AMI patients undergoing percutaneous coronary intervention between 2010 and 2015 were assessed using claim data from the Health Insurance Review and Assessment Service. Results The use of new antiplatelet agents has rapidly increased since 2013 and has been preferred over clopidogrel (Plavix; Bristol-Myers Squibb/Sanofi Pharmaceuticals) since 2015. Both prasugrel (Effient; Eli Lilly and Company) (odds ratio [OR], 0.45; 95% confidence interval [CI], 0.31–0.67; p<0.001) and ticagrelor (Brilinta; AstraZeneca Pharmaceuticals LP) (OR, 0.84; 95% CI, 0.71–0.98; p=0.032) had an independent effect on lowering 30-day mortality in a weighted multivariable logistic regression model. However, new antiplatelet agents had no significant effect on other clinical outcomes including myocardial infarction, stroke, bleeding, and readmission within 30 days. Conclusion The use of new antiplatelet agents is rapidly increasing, and they have been used more commonly than clopidogrel since 2015. We demonstrated that new antiplatelet agents have a favorable effect on reducing 30-day mortality in AMI patients in Korea.