Background: The nonsteroidal mineralocorticoid receptor blocker esaxerenone is effective in reducing blood pressure (BP). Objective: In this study, we investigated esaxerenone-driven sodium homeostasis and its association with changes in BP in Dahl salt-sensitive (DSS) hypertensive rats. Methods: In the different experimental setups, we evaluated BP by a radiotelemetry system, and sodium homeostasis was determined by an approach of sodium intake (food intake) and excretion (urinary excretion) in DSS rats with a low-salt diet (0.3% NaCl), high-salt diet (HSD, 8% NaCl), HSD plus 0.001% esaxerenone (w/w), and HSD plus 0.05% furosemide. Results: HSD-fed DSS rats showed a dramatic increase in BP with a non-dipper pattern, while esaxerenone treatment, but not furosemide, significantly reduced BP with a dipper pattern. The cumulative sodium excretion in the active period was significantly elevated in esaxerenone- and furosemide-treated rats compared with their HSD-fed counterparts. Sodium content in the skin, skinned carcass, and total body tended to be lower in esaxerenone-treated rats than in their HSD-fed counterparts, while these values were unchanged in furosemide-treated rats. Consistently, sodium balance tended to be reduced in esaxerenone-treated rats during the active period. Histological evaluation showed that esaxerenone, but not furosemide, treatment attenuated glomerulosclerosis, tubulointerstitial fibrosis, and urinary protein excretion induced by high salt loading. Conclusions: Collectively, these findings suggest that an esaxerenone treatment-induced reduction in BP and renoprotection are associated with body sodium homeostasis in salt-loaded DSS rats.

Fiber-rich green river Aonori alga is mass-cultivated in Japan; it has been reported to reduce inflammation and improve metabolic health in humans. Peroxisome proliferation-activated receptor (PPARs) are associated with metabolic disorders such as obesity and type 2 diabetes (T2DM). We evaluated the effects of supplementation with NBF2, a formula made of algal and junos citrus biomaterials, on metabolic markers in obese and diabetic rats. An experimental study was performed using 18 obese and hyperglycemic Otsuka Long-Evans Tokushima Fatty (OLETF) rats randomly assigned to high dose NBF2 (20mg/kg; n=6), low dose (10mg/kg; n=6) NBF2 drink for 6 weeks, whereas OLETF control rats received similar amount of tap water (vehicle; n=6). LETO rats were used as normal controls (n=8). Biospecimens were taken for ELISA and real-time PCR. Both high dose and low dose NBF2 increased brown adipose tissue (BAT) mass and adiponectin (APN), improved insulin sensitivity, and significantly improved glycemic and lipid (TG, LDL-c) profiles in NBF2-supplemented OLETF rats after a 6-week supplementation with NBF2 (vs. OLETF controls), as well as LDL-c (p<0.05). During the glucose tolerance test (OGTT), both NBF2 groups and LETO rats had normal glycemia by 90-minute time-point (vs. OLETF controls; p<0.01). Furthermore, intake of NBF2 up-regulated PPARa/g-mRNA and Sirt2-mRNA gene expressions in BAT, and improved blood pressure profile in OLETF rats. Findings from this research suggest that intake of NBF2 formula induces dual PPAR-a/g and Sirt2 activation, providing insights on beneficial prophylactic and therapeutic effects of this NB2 formula on dyslipidemia and hyperglycemia in T2DM.

Ulva prolifera, known as Aonori in Japan, is an edible alga species that is mass-cultivated in Japan. Supplementation with Aonori-derived biomaterials has been reported to enhance metabolic health in previous studies. This was an experimental study that evaluated the metabolic health effects of NBF2, a formula made of algal and junos Tanaka citrus-derived biomaterials, on obesity and type 2 diabetes (T2DM). We used 18 obese and hyperglycemic Otsuka Long-Evans Tokushima Fatty (OLETF) rats that were assigned randomly to three groups of six animals: a high-dose NBF2 drink (20 mg/kg) group, a low-dose (10 mg/kg) NBF2 drink group and the control group that received 2 mL of tap water daily for a total of six weeks. We also used eight LETO rats as the normal control group. In addition to the glucose tolerance test (OGTT), ELISA and real-time PCR assays were performed. High-dose and lowdose NBF2 improved insulin sensitivity, as well as glycemic and lipid profiles, as compared with control rats. The OGTT showed that both NBF2 groups and LETO rats had normalized glycemia by the 90-min time-point. NBF2 up-regulated PPARα/γ-mRNA and Sirt2-mRNA gene expressions in BAT and improved the blood pressure profile. These findings suggest that the NBF2 formula, which activates PPAR-α/γ mRNA and Sirt2-mRNA, may reverse dyslipidemia and hyperglycemia in T2DM.