Combination of tea catechins and ornithine effectively activates the urea cycle: an in vitro and human pilot study.

PURPOSE: Accumulation of ammonia causes central and peripheral fatigue. This study aimed to investigate the synergistic effect of tea catechins and low-dose ornithine in activating the urea cycle to reduce blood ammonia levels during exercise. METHODS: We used hepatocyte-like cells derived from human-induced pluripotent stem (iPS) cells to assess the effect of tea catechins combined with ornithine on urea cycle activity. The urea production and expression of key genes involved in the metabolism of urea were investigated. We then examined the synergistic improvement in ammonia metabolism by tea catechins in combination with ornithine in a human pilot study. RESULTS: Tea catechins combined with ornithine increased urea cycle activity in hepatocyte-like cells derived from human iPS cells. Intake of 538.6 mg of tea catechins with 1592 mg of ornithine for 2 consecutive days during exercise loading suppressed the exercise-induced increase in the blood ammonia concentration as well as stabilized blood glucose levels. CONCLUSION: Controlling the levels of ammonia, a toxic waste produced in the body, is important in a variety of situations, including exercise. The present study suggests that a heterogeneous combination of polyphenols and amino acids efficiently suppresses elevated ammonia during exercise in humans by a mechanism that includes urea cycle activation. TRIAL REGISTRATION: This study was registered in the University Hospital Medical Information Network Clinical Trial Registry (No. UMIN000035484, dated January 8, 2019).

Non-invasive evaluation of subjective sensitive skin by transcriptomics using mRNA in skin surface lipids.

Sensitive skin is a condition characterized by hypersensitivity to environmental stimuli, and its pathophysiology has not been fully elucidated. Questionnaires based on subjective symptoms, intervention tests, and measuring devices are used to diagnose sensitive skin; however, objective evaluation methods, including biomarkers, remain to be established. This study aimed to investigate the molecular profiles of self-reported sensitive skin, understand its pathophysiology and explore its biomarkers. Here, we analysed RNAs in skin surface lipids (SSL-RNAs), which can be obtained non-invasively by wiping the skin surface with an oil-blotting film, to compare the transcriptome profiles between questionnaire-based "sensitive" (n = 11) and "non-sensitive" (n = 10) skin participants. Exactly 417 differentially expressed genes in SSL-RNAs from individuals with sensitive skin were identified, of which C-C motif chemokine ligand 17 and interferon-γ pathways were elevated, while 50 olfactory receptor (OR) genes were downregulated. The expression of the detectable 101 OR genes was lower in individuals with sensitive skin compared to that in those with non-sensitive skin and was particularly associated with the subjective sensitivity among skin conditions. The receiver operating characteristic (ROC) curve demonstrated that the mean expression levels of OR genes in SSL-RNAs could discriminate subjective skin sensitivity with an area under the ROC curve of 0.836. SSL-RNA profiles suggest a mild inflammatory state in sensitive skin, and overall OR gene expression could be a potential indicator for sensitive skin.

Light rhythmic exercise with dietary milk fat globule membrane improves physical fitness in an elderly Japanese population: a double-blind randomized placebo-controlled trial.

This study aimed to investigate the efficacy of home-based, light gymnastic exercise plus dietary milk fat globule membrane (MFGM) intake on physical fitness of an elderly Japanese sample in a pilot, double-blind, randomized, placebo-controlled trial. Seventy-one subjects (male, n = 13; female, n = 58) were randomly assigned into two groups: placebo (n = 35 [male, n = 6; female, n = 29]) and MFGM group (n = 36 [male, n = 7; female, n = 29]). The intervention was eight weeks. Subjects ingested either MFGM (1 g/day) or placebo tablets daily and engaged in an exercise program daily. Physical function tests were performed at baseline and after four and eight weeks. Foot tapping and open-close stepping scores significantly increased from baseline to eight weeks in the MFGM group. Study results suggest daily MFGM ingestion might further enhance the effects of light-intensity exercise in healthy elderly people.

Effects of Psidium guajava Linn. leaf extract in Japanese subjects with knee pain: a randomized, double-blind, placebo-controlled, parallel pilot study.

The extract of Psidium guajava Linn. (guava) leaf was recently revealed to suppress the advance of osteoarthritis (OA) in rat anterior cruciate ligament-transection models. To investigate the efficacy of guava leaf extract in improving knee pain, which is a common symptom of OA, we conducted a double-blind parallel pilot clinical study in Japanese subjects with knee pain. The subjects, who had no medical history of knee treatment, were randomly assigned to two groups with similar total Japanese Knee Osteoarthritis Measure (JKOM) scores. During the 12-week intake period, the subjects in each group ingested 1 g of guava leaf extract (the guava group) or placebo (the placebo group) daily. At week 12, pain and stiffness in knees (one subcategory of JKOM score) in the guava group was significantly lower than that in the placebo group. Using the visual analogue scale (VAS) for knee pain, a significant association between treatment effect and test period was shown, and the guava group had a lower VAS score at week 12 than the placebo group. In conclusion, continuous intake of guava leaf extract might relieve knee pain, suggesting a potential preventive effect against OA symptoms.

Reduction in hydroxyhydroquinone from coffee increases postprandial fat utilization in healthy humans: a randomized double-blind, cross-over trial.

The present study aimed to clarify the effect of reduction in hydroxyhydroquinone (HHQ) from roasted coffee on energy utilization in humans. Indirect calorimetry showed that one-week ingestion of HHQ-reduced coffee led to significantly higher postprandial fat utilization than that of HHQ-containing coffee. This finding indicates that reduction in HHQ from coffee increases postprandial fat utilization.

Daily consumption of tea catechins improves aerobic capacity in healthy male adults: a randomized double-blind, placebo-controlled, crossover trial.

Our previous studies demonstrated that dietary supplementation with tea catechins combined with exercise improved endurance capacity in mice. This study aimed to demonstrate the effect of daily tea catechin consumption on aerobic capacity in humans. Sixteen Japanese non-athlete male subjects (aged 25-47 years) took 500 mL of a test beverage with or without tea catechins (570 mg) daily for 8 weeks and attended a training program twice a week. Aerobic capacity was evaluated by indirect calorimetry and near-infrared spectroscopy during graded cycle exercise. Catechin beverage consumption was associated with a significantly higher ventilation threshold during exercise and a higher recovery rate of oxygenated hemoglobin and myoglobin levels after graded cycle exercise when compared to subjects receiving the placebo beverage. These results indicate that daily consumption of tea catechins increases aerobic capacity when combined with semiweekly light exercise, which may be due to increased skeletal muscle aerobic capacity.

Dietary milk fat globule membrane supplementation combined with regular exercise improves skeletal muscle strength in healthy adults: a randomized double-blind, placebo-controlled, crossover trial.

BACKGROUND: Our previous studies demonstrated that dietary supplementation with milk fat globule membrane (MFGM) combined with habitual exercise improved muscle strength by stimulating neuromuscular development in mice. This study aimed to demonstrate the beneficial effects of dietary MFGM supplementation plus regular exercise on muscle strength and neuromuscular function in healthy humans. METHODS: The study was designed as a randomized, double-blind, placebo-controlled, crossover trial. Fourteen Japanese adults aged 31-48 years took daily MFGM (1 g) or placebo tablets during the 4-week study period and attended a training program twice a week. Physical function tests and surface electromyography (EMG) were conducted at baseline and at the end of the study period. RESULTS: The MFGM group had significantly greater leg extension strength than the placebo group after the 4-week study period. Surface EMG showed that the MFGM group had a significantly higher root mean square amplitude than the placebo group, which indicated that the MFGM group had higher motor unit activity. CONCLUSIONS: Dietary MFGM supplementation combined with regular exercise improves skeletal muscle strength, which may be due to increased motor unit recruitment in healthy Japanese middle-aged adults.

Dietary milk fat globule membrane improves endurance capacity in mice.

Milk fat globule membrane (MFGM) comprises carbohydrates, membrane-specific proteins, glycoproteins, phospholipids, and sphingolipids. We evaluated the effects of MFGM consumption over a 12-wk period on endurance capacity and energy metabolism in BALB/c mice. Long-term MFGM intake combined with regular exercise improved endurance capacity, as evidenced by swimming time until fatigue, in a dose-dependent manner. The effect of dietary MFGM plus exercise was accompanied by higher oxygen consumption and lower respiratory quotient, as determined by indirect calorimetry. MFGM intake combined with exercise increased plasma levels of free fatty acids after swimming. After chronic intake of MFGM combined with exercise, the triglyceride content in the gastrocnemius muscle increased significantly. Mice given MFGM combined with exercise had higher mRNA levels of peroxisome proliferator-activated receptor-γ coactivator 1α (Pgc1α) and CPT-1b in the soleus muscle at rest, suggesting that increased lipid metabolism in skeletal muscle contributes, in part, to improved endurance capacity. MFGM treatment with cyclic equibiaxial stretch consisting of 10% elongation at 0.5 Hz with 1 h on and 5 h off increased the Pgc1α mRNA expression of differentiating C2C12 myoblasts in a dose-dependent manner. Supplementation with sphingomyelin increased endurance capacity in mice and Pgc1α mRNA expression in the soleus muscle in vivo and in differentiating myoblasts in vitro. These results indicate that dietary MFGM combined with exercise improves endurance performance via increased lipid metabolism and that sphingomyelin may be one of the components responsible for the beneficial effects of dietary MFGM.

Ficus carica L. (Fig) promotes nerve regeneration in a mouse model of sciatic nerve crush.

Peripheral nerve injuries result in significant loss of motor and sensory function, and the slow rate of nerve regeneration can prolong recovery time. Thus, approaches that promote axonal regeneration are critical to improve the outcomes for patients with peripheral nerve injuries. In this study, we investigated the effects of Ficus carica L. (fig) and Vaccinium macrocarpon Ait. (cranberry), which are rich in phytochemicals with demonstrable and diverse medicinal properties, on nerve regeneration in a mouse model of sciatic nerve crush. Our investigation revealed that fig extract, but not cranberry extract, prevented the decline in muscle weight and nerve conduction velocity induced by nerve crush. The fig extract also mitigated motor function impairment, myelin thinning, and axon diameter reduction, indicating its potential to promote nerve regeneration. Furthermore, the fig extract enhanced macrophage infiltration into the nerve tissue, suggesting that it could ameliorate nerve injury by promoting tissue repair via increased macrophage infiltration. The study provides valuable insights into the potential of the fig extract as a novel agent promoting nerve regeneration. Further investigation into the mechanisms underlying the action of fig extracts is needed to translate these findings into clinical applications for patients with peripheral nerve injuries.

Effects of Milk Fat Globule Membrane Supplementation Following Exercise Training on Physical Performance in Healthy Young Adults: A Randomized Double-Blind, Placebo-Controlled Pilot Trial.

The purpose of this study was to examine whether 4 wk of daily ingestion of milk fat globule membrane (MFGM) combined with exercise training improves physical performance-muscle strength, agility and muscle power-in healthy young adults. The study was designed as a randomized, double-blind, and placebo-controlled trial. Twenty healthy young adults received either an MFGM powder containing 1.6 g of fat and 160 mg of sphingomyelin or an isocaloric placebo powder daily throughout 4 wk of power or agility training. Physical performance tests and body composition measurements were conducted before and after the 4-wk intervention. Ingestion of MFGM did not affect isometric or isokinetic muscle strength, but it was associated with a greater increase in vertical jump peak power compared with placebo. There were no significant changes in body weight or lean body mass during the intervention period in either group, and no significant differences between groups. We conclude that daily MFGM supplementation combined with exercise training has the potential to improve physical performance in young adults; however, further studies with larger sample sizes should be conducted to obtain more evidence supporting achievement of improved physical performance through MFGM supplementation.

Association of toxin-producing Clostridioides difficile with piglet diarrhea and potential transmission to humans.

The pathogenicity of Clostridioides difficile in piglets remains controversial. It is unknown whether C. difficile control helps protect piglet health. To clarify the association between C. difficile presence and piglet diarrhea, isolates were obtained from piglets with and without diarrhea. In addition, to determine the genetic relationship of C. difficile from pigs and humans, we performed whole-genome sequencing (WGS) of C. difficile isolates. Diarrheal and non-diarrheal stool samples were collected from neonatal piglets from five farms in Japan in 2021. To clarify the relationship between C. difficile derived from pigs and those from human clinical cases, WGS of C. difficile isolates was performed. Toxin-positive C. difficile were significantly more prevalent in piglets with diarrhea, although the overall frequency of C. difficile did not differ between piglets with and without diarrhea. This observation indicates an association between toxin-positive C. difficile and diarrhea in piglets. However, further studies are needed to establish a direct causal relationship and to explore other contributing factors to diarrhea in piglets. WGS results showed that C. difficile sequence type (ST) 11 including the hypervirulent PCR ribotype 078 isolates derived from Japanese pigs were closely related to ST11 of overseas strains (human clinical and animal-derived) and a Japanese human clinical strain. Toxin-positive C. difficile may cause diarrhea in piglets and hypervirulent C. difficile are spreading among pigs and human populations worldwide.

Stimulation of postprandial fat utilization in healthy humans by daily consumption of chlorogenic acids.

Long-term ingestion of coffee polyphenols (chlorogenic acids, CGAs) reduces body fat in humans and rodents. While CGA supplementation has been shown to increase fat utilization in rodents, evidence in humans is still limited. The present study clarifies the effect of daily CGA consumption on energy metabolism in humans. Eighteen healthy male subjects (36.1 ± 7.4 y of age) participated in a placebo-controlled, double-blind, crossover, intervention study with two different test beverages. The subjects consumed 185 mL of a test beverage with or without CGAs (329 mg) daily for 4 wk. The energy metabolism was evaluated by using indirect calorimetry before and after the test period during fasting and up to 180 min postprandially. Indirect calorimetry showed that a 4-wk ingestion of the CGA beverage led to a significantly higher postprandial energy expenditure than that of the control beverage. The subjects ingesting the CGA beverage exhibited higher postprandial fat utilization than those consuming the control beverage. The daily CGA consumption therefore increased postprandial fat utilization in healthy humans.

Antiviral Effect of Propylene Glycol against Envelope Viruses in Spray and Volatilized Forms.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly contagious and continues to spread worldwide. To avoid the spread of infection, it is important to control its transmission routes. However, as methods to prevent airborne infections are lacking, people are forced to take measures such as keeping distance from others or wearing masks. Here, we evaluate the antiviral activity of propylene glycol (PG), which is safe, odorless, and volatile. PG showed pronounced antiviral activity against the influenza virus (IAV) at concentrations above 55% in the liquid phase. Given its IAV inactivation mechanism, which involves increasing the fluidity of the viral membrane, PG is expected to have a broad effect on enveloped viruses. PG showed antiviral activity against SARS-CoV-2. We also developed a system to evaluate the antiviral effect of PG in spray and volatilized forms. PG was found to be effective against aerosol IAV in both forms; the effective PG concentration against IAV in the vapor phase was 87 ppmv (0.27 mg/L). These results demonstrate that PG is an effective means for viral inactivation in various situations for infection control. This technology is expected to control the spread of current and future infectious diseases capable of causing outbreaks and pandemics.

Tyrosine Is a Booster of Leucine-Induced Muscle Anabolic Response.

Leucine (Leu), an essential amino acid, is known to stimulate protein synthesis in the skeletal muscle via mTOR complex 1 (mTORC1) activation. However, the intrinsic contribution of other amino acids to Leu-mediated activation of mTORC1 signaling remains unexplored. This study aimed to identify amino acids that can promote mTORC1 activity in combination with Leu and to assess the effectiveness of these combinations in vitro and in vivo. We found that tyrosine (Tyr) enhanced Leu-induced phosphorylation of S6 kinase (S6K), an indicator of mTORC1 activity, although it exerted no such effect individually. This booster effect was observed in C2C12 cells, isolated murine muscle, and the skeletal muscles of mice orally administered the amino acids. To explore the molecular mechanisms underlying this Tyr-mediated booster effect, the expression of the intracellular Leu sensors, Sestrin1 and 2, was suppressed, and the cells were treated with Leu and Tyr. This suppression enabled Tyr alone to induce S6K phosphorylation and enhanced the booster effect, suggesting that Tyr possibly contributes to mTORC1 activation when Sestrin-GAP activity toward Rags 2 (GATOR2) is dissociated through Sestrin knockdown or the binding of Sestrins to Leu. Collectively, these results indicate that Tyr is a key regulator of Leu-mediated protein synthesis.

Protein-bound sialic acid in saliva contributes directly to salivary anti-influenza virus activity.

The oral cavity is an entrance for respiratory viruses, such as influenza. Recently, saliva has been shown to exert both antimicrobial and antiviral activities. Thus, saliva may be a biological factor that contributes to the prevention of influenza infection. However, the actual salivary anti-influenza A virus (IAV) activity in individuals and its determinant factors are unknown. By assessing individual variations in salivary anti-IAV activity in 92 people using an established new high-throughput system in this study, we found that the anti-IAV activity varied widely between individuals and showed a significant positive correlation with protein-bound sialic acid (BSA) level (ρ = 0.473; p < 0.001). Furthermore, the anti-IAV activity of saliva with enzymatically reduced BSA content was significantly lower. These results indicate that BSA is a direct regulator of salivary anti-IAV activity and is a determinant of individual differences. Additionally, after comparing the anti-IAV activity across the groups by age, anti-IAV activity in young people (aged 5-19 years) were lower than in adults aged 20-59 years and elderly people aged 60-79 years. Our study suggests that BSA levels in saliva may be important in preventing influenza infection.

Non-invasive human skin transcriptome analysis using mRNA in skin surface lipids.

Non-invasive acquisition of mRNA data from the skin can be extremely useful for understanding skin physiology and diseases. Inspired by the holocrine process, in which the sebaceous glands secrete cell contents into the sebum, we focused on the possible presence of mRNAs in skin surface lipids (SSLs). We found that measurable levels of human mRNAs exist in SSLs, where the sebum protects them from degradation by RNases. The AmpliSeq transcriptome analysis was modified to measure SSL-RNA levels, and our results revealed that the SSL-RNAs predominantly comprised mRNAs derived from sebaceous glands, the epidermis, and hair follicles. Analysis of SSL-RNAs non-invasively collected from patients with atopic dermatitis revealed increased expression of inflammation-related genes and decreased expression of terminal differentiation-related genes, consistent with the results of previous reports. Further, we found that lipid synthesis-related genes were downregulated in the sebaceous glands of patients with atopic dermatitis. These results indicate that the analysis of SSL-RNAs is a promising strategy to understand the pathophysiology of skin diseases.

The Impact of Milk Fat Globule Membrane with Exercise on Age-Related Degeneration of Neuromuscular Junctions.

Morphological changes in neuromuscular junctions (NMJs), which are synapses formed between α-motor neurons and skeletal muscle fibers, are considered to be important in age-related motor dysfunction. We have previously shown that the intake of dietary milk fat globule membrane (MFGM) combined with exercise attenuates age-related NMJ alterations in the early phase of aging. However, it is unclear whether the effect of MFGM with exercise on age-related NMJ alterations persists into old age, and whether intervention from old age is still effective when age-related changes in NMJs have already occurred. In this study, 6- or 18-month-old mice were treated with a 1% MFGM diet and daily running wheel exercise until 23 or 24 months of age, respectively. MFGM treatment with exercise was effective in suppressing the progression of age-related NMJ alterations in old age, and even after age-related changes in NMJs had already occurred. Moreover, the effect of MFGM intake with exercise was not restricted to NMJs but extended to the structure and function of peripheral nerves. This study demonstrates that MFGM intake with exercise may be a novel approach for improving motor function in the elderly by suppressing age-related NMJ alterations.

Investigation of the Oral Retention of Tea Catechins in Humans: An Exploratory Interventional Study.

Green tea catechin ingestion or gargling exhibit anti-viral activity against upper respiratory infection. We hypothesized that retention in the oral cavity could improve the anti-viral effects of catechins. The present study investigated the oral retention of catechins in humans and the effect of catechin beverage viscosity on oral retention. Two intervention studies with different test beverages, beverage-C (40 mL, containing 73.4 mg of catechins) and beverage-XT (40 mL, beverage-C containing 100 mg xanthan gum) were conducted in 20 healthy volunteers (mean age 38.7 years). Catechin concentrations were measured in buccal mucosa samples collected at 10 min, 40 min, and 60 min after ingesting test beverages, and the catechin variability of the tissue after intake was compared between test beverages. As a result, the mean (SEM) concentrations of EGCG were 99.9 (27.2), 58.2 (16.6), and 22.3 (5.7) ng/mg-mucosa at 10, 40, and 60 min, respectively, after ingestion of beverage-XT. Similarly, the catechin concentrations were 86.1 (20.3), 32.2 (5.3), and 27.8 (5.9) ng/mg-mucosa after ingestion of beverage-C. The total retention volume over 60 min tended to be slightly higher after ingestion of beverage-XT, though the difference was not statistically significant. Additional studies are needed to confirm the effect of xanthan gum on improving oral retention of catechins.

Non-invasive diagnostic tool for Parkinson's disease by sebum RNA profile with machine learning.

Parkinson's disease (PD) is a progressive neurodegenerative disease presenting with motor and non-motor symptoms, including skin disorders (seborrheic dermatitis, bullous pemphigoid, and rosacea), skin pathological changes (decreased nerve endings and alpha-synuclein deposition), and metabolic changes of sebum. Recently, a transcriptome method using RNA in skin surface lipids (SSL-RNAs) which can be obtained non-invasively with an oil-blotting film was reported as a novel analytic method of sebum. Here we report transcriptome analyses using SSL-RNAs and the potential of these expression profiles with machine learning as diagnostic biomarkers for PD in double cohorts (PD [n = 15, 50], controls [n = 15, 50]). Differential expression analysis between the patients with PD and healthy controls identified more than 100 differentially expressed genes in the two cohorts. In each cohort, several genes related to oxidative phosphorylation were upregulated, and gene ontology analysis using differentially expressed genes revealed functional processes associated with PD. Furthermore, machine learning using the expression information obtained from the SSL-RNAs was able to efficiently discriminate patients with PD from healthy controls, with an area under the receiver operating characteristic curve of 0.806. This non-invasive gene expression profile of SSL-RNAs may contribute to early PD diagnosis based on the neurodegeneration background.

Involvement of ammonia metabolism in the improvement of endurance performance by tea catechins in mice.

Blood ammonia increases during exercise, and it has been suggested that this increase is both a central and peripheral fatigue factor. Although green tea catechins (GTCs) are known to improve exercise endurance by enhancing lipid metabolism in skeletal muscle, little is known about the relationship between ammonia metabolism and the endurance-improving effect of GTCs. Here, we examined how ammonia affects endurance capacity and how GTCs affect ammonia metabolism in vivo in mice and how GTCs affect mouse skeletal muscle and liver in vitro. In mice, blood ammonia concentration was significantly negatively correlated with exercise endurance capacity, and hyperammonaemia was found to decrease whole-body fat expenditure and fatty acid oxidation-related gene expression in skeletal muscle. Repeated ingestion of GTCs combined with regular exercise training improved endurance capacity and the expression of urea cycle-related genes in liver. In C2C12 myotubes, hyperammonaemia suppressed mitochondrial respiration; however, pre-incubation with GTCs rescued this suppression. Together, our results demonstrate that hyperammonaemia decreases both mitochondrial respiration in myotubes and whole-body aerobic metabolism. Thus, GTC-mediated increases in ammonia metabolism in liver and resistance to ammonia-induced suppression of mitochondrial respiration in skeletal muscle may underlie the endurance-improving effect of GTCs.