Combined Aerobic Exercise Training and Chlorella Intake Reduces Arterial Stiffness through Enhanced Arterial Nitric Oxide Production in Obese Rats (The study was published in the academic journal Nutrients.)

【Scientific information】

Research and Development Department, Sun Chlorella Corporation

Combined Aerobic Exercise Training and Chlorella Intake Reduces Arterial Stiffness through Enhanced Arterial Nitric Oxide Production in Obese Rats
The study was published in the academic journal Nutrients.

Study objectives: The global prevalence of overweight adults and obese patients is high and continues to rise. Obesity is a lifestyle-related disease that poses additional health risks and induces various chronic conditions. Generally, obesity causes vascular endothelial dysfunction, leading to an increase in arterial stiffness, which serves as a major risk factor for predicting cardiovascular diseases.
Vascular endothelium-derived relaxing factors, such as nitric oxide (NO), maintain vascular elasticity through activation of the protein kinase B (Akt)/ endothelial NO synthase (eNOS) signaling pathway in endothelial cells. In obese patients, a decreased ability to utilize NO is thought to contribute to arterial stiffness.
Aerobic exercise training in obese patients not only reduces fat accumulation but also enhances arterial NO production via activation of the Akt/eNOS signaling pathway, thereby reducing arterial stiffness.
Chlorella contains various nutrients, including amino acids, dietary fibers, vitamins, and minerals, and has been reported to lower branchial-ankle pulse wave velocity arterial (baPWV), an indicator of arterial stiffness, while increasing blood NO levels in middle-aged and elderly individuals. Additionally, recent studies have shown that the continuous intake of Chlorella in aged mice increased NO production and improved arterial stiffness through activation of the arterial Akt/eNOS signaling pathway.
This study investigated whether the combination of habitual Chlorella intake and aerobic exercise training could further reduce arterial stiffness in obese rats.

Study method: Male OLETF rats at six weeks of age were used as an obesity model. The study included four groups of six rats each, as described below, as well as a healthy group consisting of age-equivalent male LETO rats without diabetes:

1. Healthy group
2. Obese (OBESE-SED) group
3. Obese with aerobic exercise (OBESE-ET) group
4. Obese with Chlorella intake (OBESE-CH) group
5. Obese with combined aerobic exercise and Chlorella intake (OBESE-ET+CH) group

The Healthy, OBESE-SED, and OBESE-ET groups consumed water and standard feed for eight weeks. The Chlorella intake groups (OBESE-CH and OBESE-ET+CH) consumed water and feed containing 0.5% Chlorella powder, adjusted to match the caloric content of the standard feed, for eight weeks.
The aerobic exercise groups (OBESE-ET and OBESE-ET+CH) underwent pre-training for three days on a small animal treadmill at a speed of 10–15 m/min. This was followed by treadmill training at a flat incline at 25 m/min for one hour, five days a week, for eight weeks.
After eight weeks of intervention, the aortic vessels were harvested to measure carotid-femoral pulse wave velocity (cfPWV), an indicator of arterial stiffness. Arterial Akt and eNOS phosphorylation were analyzed using Western blotting, and arterial NOx (nitrate/nitrite) concentrations were assessed with the Griess assay.

Results: First, the indicators were explained. An increase in cfPWV indicates higher arterial stiffness. Arterial Akt and eNOS are activated by phosphorylation, contributing to NO production. An increase in arterial NOx concentration indicates a reduction in arterial stiffness.

☆cfPWV
cfPWV was significantly higher in the OBESE-SED group compared to the Healthy group (p < 0.05, Figure 1). However, it was significantly lower in the OBESE-ET, OBESE-CH, and OBESE-ET+CH groups compared to the OBESE-SED group (p < 0.05, Figure 1). While there was no significant difference between the OBESE-ET and OBESE-CH groups, cfPWV in the OBESE-ET+CH group was significantly lower than in the OBESE-ET and OBESE-CH groups (p < 0.05, Figure 1).

☆Akt phosphorylation activity
This activity was significantly lower in the OBESE-SED group compared to the Healthy group (p < 0.05, Figure 2, left). However, it was significantly higher in the OBESE-ET+CH group compared to the OBESE-SED and OBESE-ET groups (p < 0.05, Figure 2, left).

☆eNOS phosphorylation activity
This activity was significantly lower in the OBESE-SED and OBESE-CH groups compared to the Healthy group (p < 0.05, Figure 2, right). However, it was significantly higher in the OBESE-ET and OBESE-ET+CH groups compared to the OBESE-SED and OBESE-CH groups (p < 0.05, Figure 2, right).

☆Arterial NOx concentration
NOx levels were significantly lower in the OBESE-SED group compared to the Healthy group (p < 0.05, Figure 3). However, they were significantly higher in the OBESE-ET, OBESE-CH, and OBESE-ET+CH groups compared to the OBESE-SED group. While no significant difference was observed between the OBESE-ET and OBESE-CH groups, NOx levels in the OBESE-ET+CH group were significantly higher than in the OBESE-ET and OBESE-CH groups (p < 0.05, Figure 3).

Additionally, arterial NOx concentration was positively correlated with arterial eNOS phosphorylation activity (p < 0.05, r = 0.489, Figure 4A) and negatively correlated with cfPWV (p < 0.05, r = -0.568, Figure 4B).

[Conclusion]

These results suggest that the combination of habitual Chlorella intake and aerobic exercise training further reduces arterial stiffness in obese rats by increasing arterial NO production through activation of the Akt/eNOS signaling pathway.; Data are presented as mean ± standard deviation. X indicates the mean value, and ○ represents individual data points. *p < 0.05 compared to the Healthy group, †p < 0.05 compared to the OBESESED-SED group, ‡p < 0.05 compared to the OBESE-CH group, and §p < 0.05 compared to the OBESE-ET group.; Data are presented as mean ± standard deviation. X indicates the mean value, and ○ represents individual data points. *p < 0.05 compared to the Healthy group, †p < 0.05 compared to the OBESESED-SED group, ‡p < 0.05 compared to the OBESE-CH group, and §p < 0.05 compared to the OBESE-ET group.; Data are presented as mean ± standard deviation. X indicates the mean value, and ○ represents individual data points. *p < 0.05 compared to the Healthy group, †p < 0.05 compared to the OBESESED-SED group, ‡p < 0.05 compared to the OBESE-CH group, and §p < 0.05 compared to the OBESE-ET group.

Details

Academic soceity：: Nutrients
Title：: Combined Aerobic Exercise Training and Chlorella Intake Reduces Arterial Stiffness through Enhanced Arterial Nitric Oxide Production in Obese Rats
Authors：: Henry Yamazaki, Shumpei Fujie*, Kenichiro Inoue, Masataka Uchida, Motoyuki Iemitsu
Affiliation：: Faculty of Sport and Health Science, Ritsumeikan University
* Author to whom correspondence should be addressed.

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Combined Aerobic Exercise Training and Chlorella Intake Reduces Arterial Stiffness through Enhanced Arterial Nitric Oxide Production in Obese Rats

The Research and Development Department at Sun Chlorella Corp. reports detail of analysis and studies for health food, and supplements.