(P09-031-24) Laminaran Intake Attenuates Hypertension in 2-Kidney, 1-Clip Renovascular Hypertensive Rats via Glucagon-Like Peptide-1

Objectives: Laminaran is one of the polysaccharides contained in brown algae. It has been reported that laminaran significantly increases serum levels of glucagon-like peptide-1 (GLP-1), and chronic GLP-1 administration has been shown to improve endothelial dysfunction and lower blood pressure (BP) in a rat model of hypertension. However, to our knowledge, since the effect of laminaran intake on BP has not been reported, we investigated that in 2-kidney, 1-clip (2K1C) renovascular hypertensive rats in this study.

Methods: First, rats with 2K1C or sham-operated rats (SHAM) were fed a control diet (CTL) or a 1.0% (w/w) laminaran diet (LAM) for 6 weeks. Systolic BP (SBP) was measured by tail-cuff method once a week. In the end, mean arterial BP (MAP) was measured in the rats under anesthesia. Plasma total GLP-1 levels were also measured. Second, rats from the same groups as in the first experiment were treated twice daily with intraperitoneal injections of phosphate-buffered saline or a GLP-1 receptor antagonist, exendin-(9-39) (Exe, 75 μg/kg/day) at 5-6 weeks postoperatively, and SBP and MAP were measured.

Results: SBP and MAP in 2K1C rats were significantly higher than in SHAM rats when fed CTL. Those in 2K1C-LAM rats were significantly lower than in 2K1C-CTL rats. However, no significant difference in SBP and MAP was observed between SHAM-CTL rats and SHAM-LAM rats. Exe suppressed the antihypertensive effect of dietary laminaran. Laminaran increased plasma GLP-1 in 2K1C rats. Body weight did not significantly change among the groups throughout the experiments.

Conclusions: Dietary laminaran may alleviate 2K1C renovascular hypertension, probably via GLP-1.

Funding Sources: This study was supported by Research Grants from the Mishima Kaiun Memorial Foundation to Saki Maruyama.