Cardiovascular Disease Protective Effect of Allicin Through Gut Microbiota Modulation (FS07-08-19)

Objectives

Red meat consumption can promote atherosclerosis since the gut microbiota can metabolize L-carnitine from meat into trimethylamine N-oxide (TMAO) which is a causative risk for cardiovascular disease. Garlic has long been associated with health benefits. Allicin is a major bioactive compound typically found in blend fresh garlic. It possesses the antibacterial, anti-oxidant, and cholesterol-lowering effects. The aim of this study is to investigate the effect allicin on the gut microbiota and its metabolites on cardiovascular disease by using the long-term carnitine treatment ApoE (-/-) mice model.

Methods

8-week old male ApoE (-/-) mice were divided into 4 groups: (1) Control, (2) 1.3% Carnitine, (3) Allicin (10 mg/kg), and (4) 1.3% Carnitine + Allicin (10 mg/kg). After 15 weeks, we performed the carnitine challenge test by oral gavage of d9-carnitine to evaluate the TMAO production ability of the gut microbiota. The serum was analyzed for carnitine, trimethylamine (TMA) and TMAO levels by using LC-MS/MS. Other biochemistry was checked by an automatic blood analyzer. Morphological changes of aortic plaque formation were observed using oil red staining. The gut microbiome was analyzed by using 16S rDNA amplicon sequencing in Illumina Miseq platform.

Results

The results showed that allicin supplementation in the carnitine group exhibited the reduction of aortic lesion up to 34.2% as compared with carnitine group without allicin supplementation (P < 0.01). The carnitine challenge test indicated the d9-TMAO level of carnitine with allicin supplementation group tend to be reduced compared with carnitine-fed mice. Principal coordinate analysis of the feces microbiota composition was significantly different (ADONIS: P < 0.001) for each group. The linear discriminant analysis (LDA) effect size (LEfSe) results demonstrated that Akkermansia was enriched in the carnitine-fed group. In contrast, the carnitine-fed mice with allicin supplementation were abundance with Lachnospiraceae.

Conclusions

Allicin may exhibit the cardiovascular disease protective effect through modulation of gut microbiota-TMAO-atherosclerosis pathway.

Funding Sources

MOST 107-2321-B-002 -017 -.

Supporting Tables, Images and/or Graphs

Water Extract of Gastrodia Elate Blume May Ameliorate Subchronic and Mild Social Defeat Stress-induced Behavior Through Gut-brain Axis in Mice (P14-018-19)

Objectives

Gut has been known as the second brain and affects the brain via various pathways such as neurotransmitter modulation. We previously showed that water extract of Gastrodia elate Blume (WGE) exerts antidepression-like effect in forced swimming test. However, the impact of WGE on gut in subchronic and mild social defeat stress (sCSDS) model has not studied. Thus, we investigate the potential gut-brain linked mechanisms of WGE in relieving stress-induced depression-like behaviors which may result from the tryptophan (TRP) metabolism in mice subjected to sCSDS model.

Methods

C57/BL6J mice were divided into 6 groups: control (CTR), control with antibiotics (CTR + A), sCSDS, sCSDS with WGE (sCSDS + WGE), sCSDS with antibiotics (sCSDS + A) and sCSDS with antibiotics and WGE (sCSDS + A + WGE). Mice were administered 500 mg/kg body weight (BW) of WGE for 30 days and antibiotics by 10 ml/kg BW (0.1 mg/ml amphotericin B for the first 2 days, and then mixed with 5 mg/ml vancomycin, 10 mg/ml neomycin, 10 mg/ml metronidazol and 0.1 mg/ml amphotericin B for the next 28 days by gavage with ampicillin 1 mg/ml in drinking water), otherwise the sCSDS paradigm for 10 days, exclude the CTR groups. A social interaction test was conducted to assess the antidepression-like effects, while serum corticosterone (CORT) was tested as a stress indicator. Brain was isolated to dissect the TRP metabolism by using high performance liquid chromatography with electrochemical detection (HPLC-ECD).

Results

WGE significantly reversed the depression-like phenotypes, such as BW loss, social avoidance and stress index, serum CORT induced by sCSDS (P < 0.05). Whereas antibiotics administration elevated BW (P < 0.05). Treatment with antibiotics and WGE significantly increased social avoidance (P < 0.05). HPLC-ECD indicated WGE slightly normalized the 5-hydroxyindoleacetic acid (5-HIAA)/serotonin (5-HT) ratio, while antibiotics significantly decreased it, also significantly increased 5-HT and 5-HT/TRP ratio in prefrontal cortex (P < 0.05). In general, high levels of 5-HT in brain induced by sCSDS with antibiotics may linked to aggression, while WGE treatment reverse it.

Conclusions

The antidepression-like effects of WGE might be mediated by the regulation of TRP metabolism in gut-brain axis suggested to be a potential pathway to prevent depression.

Funding Sources

N/A.

Supporting Tables, Images and/or Graphs