ABSTRACT
Endothelial dysfunction is associated with hypertension, atherosclerosis, and metabolic syndrome. Phycocyanin is a pigment found in the blue-green algae, Spirulina, which possesses antihypertensive effect. In this study, we hypothesized that phycocyanin derived from Spirulina exerts antihypertensive actions by improving endothelial dysfunction in metabolic syndrome. Spontaneously hypertensive/NIH-corpulent (SHR/NDmcr-cp) rats were divided into 4 groups then fed a normal diet with or without phycocyanin (2500-, 5000-, or 10,000-mg/kg diet) for 25 weeks. At 34 weeks of age, although systolic blood pressure was not significantly different among groups, phycocyanin-fed groups exhibited a dose-dependent decrease in blood pressure. Serum levels of adiponectin and messenger RNA levels of adiponectin and CCAAT/enhancer-binding protein α in the adipose tissue of rats fed diets containing phycocyanin tended to be higher than those of rats fed a normal diet, but the differences were not statistically significant. Immunohistochemistry analysis showed a significant and positive correlation between aortic endothelial nitric oxide synthase (eNOS) expression levels, a downstream target of the adiponectin receptor, and serum adiponectin levels, although there were no significant differences in eNOS expression among groups. There was also no significant correlation between eNOS expression levels and systolic blood pressure. These results suggest that long-term administration of phycocyanin may ameliorate systemic blood pressure by enhancing eNOS expression in aorta that is stimulated by adiponectin. Phycocyanin may be beneficial for preventing endothelial dysfunction-related diseases in metabolic syndrome.
Subject(s)
Adiponectin/blood , Antihypertensive Agents/pharmacology , Hypertension/prevention & control , Metabolic Syndrome/blood , Phycocyanin/pharmacology , Animals , Aorta/drug effects , Aorta/metabolism , Blood Pressure/drug effects , Body Weight , CCAAT-Enhancer-Binding Protein-alpha/metabolism , Cyanobacteria/chemistry , Disease Models, Animal , Endothelium, Vascular/drug effects , Endothelium, Vascular/metabolism , Energy Intake , Hypertension/physiopathology , Liver/drug effects , Liver/metabolism , Male , Nitric Oxide Synthase Type III/metabolism , Organ Size/drug effects , Rats , Rats, Inbred SHR , Receptors, Adiponectin/drug effectsABSTRACT
Serum alanine aminotransferase (ALT) concentration is the most commonly used marker for hepatocellular injury. We investigated the suitable cutoff value of serum ALT for the diagnosis or prediction of fatty liver. In 1578 Japanese adults (1208 men, 370 women; 35-69 years of age) who visited our center both in 2000 and between April 2007 and March 2008 (2007-2008), serum ALT concentration was an independent predictor of fatty liver in men in 2000 and in both sexes in 2007-2008. A significant increase in the frequency of fatty liver was detected in participants with elevated serum ALT concentrations, and serum levels of ALT in 2000 were associated with fatty liver in 2007-2008 when the cutoff value was set at 30 IU/L in men and 19 IU/L in women. The frequency of fatty liver in 2007-2008 was significantly lower in participants without fatty liver in 2000 whose serum ALT decreased between 2000 and 2007-2008. Our results suggest that serum ALT might be not only an indicator of fatty liver but also a predictor of the regression of fatty liver, and cutoff values of serum ALT of 30 IU/L in men and 19 IU/L in women are suitable for the screening of fatty liver.
