Protective Effect of Gamma Aminobutyric Acid against Aggravation of Renal Injury Caused by High Salt Intake in Cisplatin-Induced Nephrotoxicity.

Gamma-aminobutyric acid (GABA) is one of the inhibitory neurotransmitters. Several studies have suggested that GABA supplements can reduce blood pressure and modulate the renal immune system in vitro and in vivo. In the present study, we investigated the effect of GABA-enriched salt as an alternative to traditional salt on aggravated renal injury by high salt intake in cisplatin-induced nephrotoxicity mice. High salt intake accelerated the increase of biomarkers, such as blood urea nitrogen and serum creatinine levels for renal injury in cisplatin-induced nephrotoxicity mice. However, oral administration of GABA-contained salt notably suppressed serum BUN and creatinine levels. The efficacy of GABA salt was superior to lacto GABA salt and postbiotics GABA salt. Furthermore, GABA-enriched salt markedly restored histological symptoms of nephrotoxicity including renal hypertrophy, tubular dilation, hemorrhage, and collagen deposition aggravated by salt over-loading in cisplatin-exposed mice. Among them, GABA salt showed a higher protective effect against cisplatin-induced renal histological changes than lacto GABA salt and postbiotics GABA salt. In addition, administration of high salt significantly enhanced expression levels of apoptosis and inflammatory mediators in cisplatin-induced nephrotoxicity mice, while GABA-enriched salt greatly down-regulated the expression of these mediators. Taken together, these results demonstrate the protective effect of GABA against damage caused by high salt intake in cisplatin-induced renal toxicity. Its mechanism may be due to the suppression of hematological and biochemical toxicity, apoptosis, and inflammation. In conclusion, although the protective efficacy of GABA salt on renal injury is different depending on the sterilization and filtration process after fermentation with L. brevis BJ20 and L. plantarum BJ21, our findings suggest that GABA-enriched salt has a beneficial effect against immoderate high salt intake-mediated kidney injury in patients with cisplatin-induced nephrotoxicity.

Fermented Oyster Extract Attenuated Dexamethasone-Induced Muscle Atrophy by Decreasing Oxidative Stress.

It is well known that oxidative stress induces muscle atrophy, which decreases with the activation of Nrf2/HO-1. Fermented oyster extracts (FO), rich in γ-aminobutyric acid (GABA) and lactate, have shown antioxidative effects. We evaluated whether FO decreased oxidative stress by upregulating Nrf2/HO-1 and whether it decreased NF-κB, leading to decreased IL-6 and TNF-α. Decreased oxidative stress led to the downregulation of Cbl-b ubiquitin ligase, which increased IGF-1 and decreased FoxO3, atrogin1, and Murf1, and eventually decreased muscle atrophy in dexamethasone (Dexa)-induced muscle atrophy animal model. For four weeks, mice were orally administered with FO, GABA, lactate, or GABA+Lactate, and then Dexa was subcutaneously injected for ten days. During Dexa injection period, FO, GABA, lactate, or GABA+Lactate were also administered, and grip strength test and muscle harvesting were performed on the day of the last Dexa injection. We compared the attenuation effect of FO with GABA, lactate, and GABA+lactate treatment. Nrf2 and HO-1 expressions were increased by Dexa but decreased by FO; SOD activity and glutathione levels were decreased by Dexa but increased by FO; NADPH oxidase activity was increased by Dexa but decreased by FO; NF-κB, IL-6, and TNF-α activities were increased by Dexa were decreased by FO; Cbl-b expression was increased by Dexa but restored by FO; IGF-1 expression was decreased by Dexa but increased by FO; FoxO3, Atrogin-1, and MuRF1 expressions were increased by Dexa but decreased by FO. The gastrocnemius thickness and weight were decreased by Dexa but increased by FO. The cross-sectional area of muscle fiber and grip strength were decreased by Dexa but increased by FO. In conclusion, FO decreased Dexa-induced oxidative stress through the upregulation of Nrf2/HO-1. Decreased oxidative stress led to decreased Cbl-b, FoxO3, atrogin1, and MuRF1, which attenuated muscle atrophy.

Gamma-Aminobutyric Acid (GABA) Promotes Growth in Zebrafish Larvae by Inducing IGF-1 Expression via GABAA and GABAB Receptors.

Insulin-like growth factor-1 (IGF-1) primarily increases the release of gamma-aminobutyric acid (GABA) in neurons; moreover, it is responsible for the promotion of longitudinal growth in children and adolescents. Therefore, in this study, we investigated whether exogenous GABA supplementation activates IGF-mediated growth performance. Zebrafish larvae treated with GABA at three days post fertilization (dpf) showed a significant increase in the total body length from 6 to 12 dpf through upregulation of growth-stimulating genes, including IGF-1, growth hormone-1 (GH-1), growth hormone receptor-1 (GHR-1), and cholecystokinin A (CCKA). In particular, at 9 dpf, GABA increased total body length from 3.60 ± 0.02 to 3.79 ± 0.03, 3.89 ± 0.02, and 3.92 ± 0.04 mm at concentrations of 6.25, 12.5, and 25 mM, and the effect of GABA at 25 mM was comparable to 4 mM ß-glycerophosphate (GP)-treated larvae (3.98 ± 0.02 mm). Additionally, the highest concentration of GABA (50 mM) -induced death in 50% zebrafish larvae at 12 dpf. GABA also enhanced IGF-1 expression and secretion in preosteoblast MC3T3-E1 cells, concomitant with high levels of the IGF-1 receptor gene (IGF-1R). In zebrafish larvae, the GABA-induced growth rate was remarkably decreased in the presence of an IGF-1R inhibitor, picropodophyllin (PPP), which indicates that GABA-induced IGF-1 enhances growth rate via IGF-1R. Furthermore, we investigated the effect of GABA receptors on growth performance along with IGF-1 activation. Inhibitors of GABAA and GABAB receptors, namely bicuculline and CGP 46381, respectively, considerably inhibited GABA-induced growth rate in zebrafish larvae accompanied by a marked decrease in the expression of growth-stimulating genes, including IGF-1, GH-1, GHR-1, and CCKA, but not with an inhibitor of GABAC receptor, TPMPA. Additionally, IGF-1 and IGF-1R expression was impaired in bicuculline and CGP 46381-treated MC3T3-E1 cells, but not in the cells treated with TPMPA. Furthermore, treatment with bicuculline and CGP 46381 significantly downregulated GABA-induced IGF-1 release in MC3T3-E1 cells. These data indicate that GABA stimulates IGF-1 release via GABAA and GABAB receptors and leads to growth promotion performance via IGF-1R.

Efficacy and safety of fermented oyster extract for height of children with short stature: a randomized placebo-controlled trial.

BACKGROUND: Some experimental studies have established the effect of oysters on the promotion of body growth. Yet, there is a lack of human clinical studies. The objective of this study was to evaluate the effect of a fermented oyster (FO) extract on the increase in the height of children with stature in the 25th percentile by age. METHODS: In total, 100 children (6-11 years old) were randomly divided into two (FO or control) groups. For 24 weeks, the subjects in the FO group took the FO extract once daily before sleeping, whereas the control group took placebo extracts, simultaneously. We evaluated the height gain, height velocity (HV), height standard deviation score (SDS), urine deoxypyridinoline (DPD), growth hormone (GH), insulin-like growth factor (IGF-1), and IGF binding protein 3 (IGFBP-3). RESULTS: The height gain and height SDS were significantly higher in the FO group than in the placebo group after 24 weeks (height gain: p < 0.001, height SDS: p < 0.005). The HV was also significantly higher in the FO group than in the placebo group after the 6th and 24th week (p = 0.001, p = 0.004). After 24 weeks, we observed a decrease in GH, IGF, and IGFBP-3 in both groups. However, serum IGFBP-3 level in the FO group reduced less than placebo group. CONCLUSION: FO supplementation may help to increase the height of children, and the effect might be mediated via effects on the IGFBP-3 levels.

Gamma-aminobutyric acid-salt attenuated high cholesterol/high salt diet induced hypertension in mice.

Excessive salt intake induces hypertension, but several gamma-aminobutyric acid (GABA) supplements have been shown to reduce blood pressure. GABAsalt, a fermented salt by L. brevis BJ20 containing GABA was prepared through the post-fermentation with refined salt and the fermented GABA extract. We evaluated the effect of GABA-salt on hypertension in a high salt, high cholesterol diet induced mouse model. We analyzed type 1 macrophage (M1) polarization, the expression of M1 related cytokines, GABA receptor expression, endothelial cell (EC) dysfunction, vascular smooth muscle cell (VSMC) proliferation, and medial thicknesses in mice model. GABA-salt attenuated diet-induced blood pressure increases, M1 polarization, and TNF-α and inducible nitric oxide synthase (NOS) levels in mouse aortas, and in salt treated macrophages in vitro. Furthermore, GABA-salt induced higher GABAB receptor and endothelial NOS (eNOS) and eNOS phosphorylation levels than those observed in salt treated ECs. In addition, GABA-salt attenuated EC dysfunction by decreasing the levels of adhesion molecules (E-selectin, Intercellular Adhesion Molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1]) and of von Willebrand Factor and reduced EC death. GABA-salt also reduced diet-induced reductions in the levels of eNOS, phosphorylated eNOS, VSMC proliferation and medial thickening in mouse aortic tissues, and attenuated Endothelin-1 levels in salt treated VSMCs. In summary, GABA-salt reduced high salt, high cholesterol diet induced hypertension in our mouse model by reducing M1 polarization, EC dysfunction, and VSMC proliferation.

In Vitro and In Vivo Effects of Fermented Oyster-Derived Lactate on Exercise Endurance Indicators in Mice.

Exogenous lactate administration has more recently been investigated for its various prophylactic effects. Lactate derived from potential functional foods, such as fermented oyster extract (FO), may emerge as a practical and effective method of consuming exogenous lactate. The current study endeavored to ascertain whether the lactate derived from FO may act on muscle cell biology, and to what extent this may translate into physical fitness improvements. We examined the effects of FO in vitro and in vivo, on mouse C2C12 cells and exercise performance indicators in mice, respectively. In vitro, biochemical analysis was carried out to determine the effects of FO on lactate content and muscle cell energy metabolism, including adenosine triphosphate (ATP) activity. Western blot analysis was also utilized to measure the protein expression of total adenosine monophosphate-activated protein kinase (AMPK), p-AMPK (Thr172), lactate dehydrogenase (LDH), succinate dehydrogenase (SDHA) and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) in response to FO administration. Three experimental groups were formed: a positive control (PC) treated with 1% horse serum, FO10 treated with 10 µg/mL and FO50 treated with 50 µg/mL. In vivo, the effects of FO supplementation on exercise endurance were measured using the Rota-rod test, and Western blot analysis measured myosin heavy-chain 2 (MYH2) to assess skeletal muscle growth, alongside p-AMPK, total-AMPK, PGC-1α, cytochrome C and UCP3 protein expression. Biochemical analysis was also performed on muscle tissue to measure the changes in concentration of liver lactate, lactate dehydrogenase (LDH), glycogen and citrate. Five groups (n = 10/per group) consisted of a control group (CON), exercise group (Ex), positive control treated with Ex and 500 mg/kg Taurine (Ex-Tau), Ex and 100 mg/kg FO supplementation (Ex-FO100) and Ex and 200 mg/kg FO supplementation (Ex-FO200) orally administered over the 4-week experimental period.FO50 significantly increased PGC-1α expression (p < 0.001), whereas both FO10 and FO50 increased the expression of p-AMPK (p < 0.001), in C2C12 muscle cells, showing increased signaling important for mitochondrial metabolism and biogenesis. Muscle lactate levels were also significantly increased following FO10 (p < 0.05) and FO50 (p < 0.001). In vivo, muscle protein expression of p-AMPK (p < 0.05) and PGC-1α were increased, corroborating our in vitro results. Cytochrome C also significantly increased following FO200 intake. These results suggest that the effects of FO supplementation may manifest in a dose-response manner. FO administration, in vitro, and supplementation, in vivo, both demonstrate a potential for improvements in mitochondrial metabolism and biogenesis, and even for potentiating the adaptive effects of endurance exercise. Mechanistically, lactate may be an important molecule in explaining the aforementioned positive effects of FO.

Gamma Aminobutyric Acid-Enriched Fermented Oyster (Crassostrea gigas) Increases the Length of the Growth Plate on the Proximal Tibia Bone in Sprague-Dawley Rats.

Bone growth during childhood and puberty determines an adult's final stature. Although several prior studies have reported that fermented oyster (FO) consisting of a high amount of gamma aminobutyric acid can be attributed to bone health, there is no research on the efficacy of FO on growth regulation and the proximal tibial growth plate. Therefore, in this study, we investigated the effect of FO oral administration on hepatic and serum growth regulator levels and the development of the proximal tibial growth plate in young Sprague-Dawley rats. Both oral administration of FO (FO 100, 100 mg/kg FO and FO 200, 200 mg/kg FO) and subcutaneous injection of recombinant human growth hormone (rhGH, 200 µg/kg of rhGH) for two weeks showed no toxicity. Circulating levels of growth hormone (GH) significantly increased in the FO 200 group. The expression and secretion of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) were enhanced by FO administration. FO administration promoted the expression of bone morphogenic proteins IGF-1 and IGFBP-3 in the proximal tibial growth plate. This positive effect of FO resulted in incremental growth of the entire plate length by expanding the proliferating and hypertrophic zones in the proximal tibial growth plate. Collectively, our results suggested that oral administration of FO is beneficial for bone health, which may ultimately result in increased height.

Effect of fermented oyster extract on growth promotion in Sprague-Dawley rats.

BACKGROUND: Oysters (Crassostrea gigas) are a popular marine product worldwide and have the advantage of nutritional benefits. This study aimed to investigate the effect of fermented oyster extract (FO) on growth promotion, including analysis of body size, bone microarchitecture, hematology and biochemistry in vivo. METHODS: The amount of nutrients and gamma aminobutyric acid (GABA) were determined. Sprague-Dawley rats were randomly divided into four groups: the control group, FO 50 group (FO 50 mg/kg), and FO 100 group (FO 100 mg/kg) were administered orally once daily and the recombinant human growth hormone (rhGH) group (200 µg/kg) was intraperitoneally injected once daily for 14 days. RESULTS: Oral administration of FO 100 significantly increased body length and had no effect on organ damage or hematological profiles. However, administration of rhGH significantly induced hypertrophy of the liver, kidney and spleen along with a marked increase in body length. Tibia length and the growth plate were increased, and bone morphometric parameters were slightly improved by FO and rhGH administration. Serum analysis showed that the levels of GH and insulin like growth factor-1 (IGF-1) were slightly upregulated by FO administration. Nevertheless, the protein expression of hepatic IGF-1 was markedly increased by FO 100 and rhGH administration. CONCLUSIONS: FO have high content of GABA, and induced positive effects on body length, tibial length, growth-plate length and hepatic IGF-1 synthesis in SD rats with no toxicity or alterations of hematological profile. Therefore, these results suggest that GABA-enriched FO could be considered a potential alternative treatment for growth stimulation.

In vitro anti-osteoporosis properties of diverse Korean Drynariae rhizoma phenolic extracts.

Drynariae rhizoma has been used to prevent bone loss that occurs with increasing age. However, the chemical compounds in extracts that act on bone metabolism in herbal medicine are poorly understood. This study aimed to investigate and compare the extraction efficacy of polyphenolic compounds, antioxidant activity, and in vitro anti-osteoporosis properties of water extract (DR-DW) and ethanol extract (DR-EtOH) from D. rhizoma. Total phenolics and flavonoids were better extracted with 70% EtOH, and this extraction method also resulted in higher antioxidant activity and in vitro anti-osteoporosis properties in these extracts. In particular, the contents of phloroglucinol, protocatechuic acid ethyl ester, 2-amino-3,4-dimethyl-benzoic acid, 3-(3,5-dimethyl-pyrazol-1-yl)-benzoic acid, chlorogenic acid, syringic acid, trans-ferulic acid, (-)-epigallocatechin, epigallocatechin gallate, quercetin dehydrate, luteolin and emodin in DR-EtOH were higher than those in DR-DW. These results indicated that DR-EtOH could be a good source of natural herbs with anti-osteoporosis properties.

Effect of a combination of low level ozone and metal ions on reducing Escherichia coli O157:H7 and Listeria monocytogenes.

Ozonated water has been used as a strong antimicrobial agent against foodborne pathogens. In this study, the combined effect of low level ozonated water and different added components, including 0.2% starch and metal ions (1 mM CuCl2·2H2O and 0.1 mM AgNO3), on inactivation of Escherichia coli O157:H7 and Listeria monocytogenes was investigated. Treatment with 0.4 ppm ozonated water for 30 min resulted in a maximum log reduction in E. coli O157:H7 and L. monocytogenes compared to initial bacterial counts. The log reductions of bacteria in a starch solution containing ozonated water were slightly higher than those in ozonated water alone. Furthermore, the log reductions of E. coli O157:H7 (2.59 and 4.71 log cfu/mL) and L. monocytogenes (2.53 and 4.28 log cfu/mL) in a metal ion solution containing 0.2 and 0.4 ppm ozone for 30 min were significantly higher than those of the water and starch added groups (p < 0.05). These results indicate that a combination of ozonated water and metal ions may be useful as a antimicrobial agent.

13-Week oral toxicity study of oil derived from squid (Todarodes pacificus) in Sprague-Dawley rats.

Recommendations to increase the consumption of the long-chain omega-3 fatty acids are challenged by the global problem of declining fish stocks. Non-traditional and more sustainable sources of the long-chain omega-3 fatty acids are needed. Squid (Todarodes pacificus) represents a uniquely sustainable source of these fatty acids. A 13-week oral toxicity study was conducted in male and female Sprague-Dawley rats administered either 0, 250, 500, or 1000µl/kg body weight (bw)/day of a refined squid oil. All of the rats survived through to the end of the study. All of the rats grew normally and had normal clinical and ophthalmic observations. No signs of toxicity were evident from clinical chemistry, hematology, and urinalysis data measured. No abnormal findings attributable to exposure to purified squid oil were observed following the necropsy of male and female rats and the histopathological examination of the organs. The no-observed-adverse-effect level for refined squid oil was determined to be 1000µl/kg bw/day, the highest dose tested.