Platinum-based anticancer drugs-induced downregulation of myosin heavy chain isoforms in skeletal muscle of mouse.

Cisplatin, a platinum-based anticancer drug used frequently in cancer treatment, causes skeletal muscle atrophy. It was predicted that the proteolytic pathway is enhanced as the mechanism of this atrophy. Therefore, we investigated whether a platinum-based anticancer drug affects the expression of the major proteins of skeletal muscle, myosin heavy chain (MyHC). Mice were injected with cisplatin or oxaliplatin for four consecutive days. C2C12 myotubes were treated using cisplatin and oxaliplatin. Administration of platinum-based anticancer drug reduced quadriceps mass and muscle strength compared to the control group. Protein levels of all MyHC isoforms were reduced in the platinum-based anticancer drug groups. However, only Myh2 (MyHC-IIa) gene expression in skeletal muscle of mice treated with platinum-based anticancer drugs was found to be reduced. Treatment of C2C12 myotubes with platinum-based anticancer drugs reduced the protein levels of all MyHCs, and treatment with the proteasome inhibitor MG-132 restored this reduction. The expression of Mef2c, which was predicted to act upstream of Myh2, was reduced in the skeletal muscle of mice treated systemically with platinum-based anticancer drug. Degradation of skeletal muscle MyHCs by proteasomes may be a factor that plays an important role in muscle mass loss in platinum-based anticancer drug-induced muscle atrophy.

Green tea extract prevents CPT-11-induced diarrhea by regulating the gut microbiota.

Irinotecan (CPT-11) is an anticancer drug with indications for use in treating various cancers, but severe diarrhea develops as a side effect. We investigated the effects of green tea extract (GTE) on CPT-11-induced diarrhea, focusing on ß-glucuronidase and intestinal UGT1A1. When CPT-11 was administered to rats alone, the fecal water content was approximately 3.5-fold higher in this group than in the control group, and diarrhea developed. The fecal water content in the GTE-treated group was significantly higher than that in the control group, but the difference was smaller than that between the group treated with CPT-11 alone and the control group, and diarrhea improved. When CPT-11 was administered alone, the abundances of Bacteroides fragilis and Escherichia coli, which are ß-glucuronidase-producing bacteria, increased and interleukin-6 and interleukin-1ß mRNA levels in the colon increased, but GTE suppressed these increases. CPT-11 decreased colon UGT1A1 and short-chain fatty acid levels; however, this decrease was suppressed in the GTE-treated group. The findings that GTE decreases the abundance of ß-glucuronidase-producing bacteria and increases colon UGT1A1 levels, thereby decreasing the production of the active metabolite SN-38 in the intestinal tract, indicate that GTE ameliorates CPT-11-induced diarrhea.

Effectiveness of Displaying Traffic Light Food Labels on the Front of Food Packages in Japanese University Students: A Randomized Controlled Trial.

Nutrition labeling on the front of food packages has been implemented worldwide to help improve public health awareness. In this randomized double-blind controlled trial, we used a Google Forms questionnaire to evaluate the effectiveness of nutrition labeling on food packages in university students. The questionnaire, ultimately completed by 247 students, included 15 dietary images from which they were asked to choose what they wanted to eat for breakfast, lunch, and dinner the following day. For the interventional (traffic light food [TLF]) group only, TLF labels were displayed on dietary images. This group had a significantly higher proportion of people conscious of healthy eating during all meals than the control group, and the effect of TLF labeling on choosing meals was the highest for lunch. In addition to the indicated nutritional components, the TLF group had a significantly higher proportion of people who were conscious of the ones of protein and dietary fiber that were not indicated on the label. The use of TLF labels resulted in an increase in the proportion of people choosing a healthy diet as well as being conscious of their nutritional components. Therefore, the use of TLF labels may help promote healthy dietary choices in Japan.

Downregulation of Sparc-like protein 1 during cisplatin-induced inhibition of myogenic differentiation of C2C12 myoblasts.

Patients with cancer often experience muscle atrophy, which worsens their prognosis. Decreased muscle regenerative capacity plays an important role in the complex processes involved in muscle atrophy. Administration of cisplatin, a cancer chemotherapeutic agent, has been implicated as a cause of muscle atrophy. In this study, we examined whether cisplatin affects the differentiation of myoblasts into myotubes. We treated C2C12 myoblasts with a differentiation medium containing cisplatin and its vehicle during for 8 days and observed the changes in the expression of myosin heavy chain (MyHC) and myogenin in the myoblasts. Cisplatin was injected in mice for 4 consecutive days; on Day 5, the mice quadriceps muscles were sampled and examined. The expression of MyHCs increased and that of myogenin decreased after cisplatin treatment. The secretion of acidic cysteine-rich proteins (e.g., Sparc proteins) reportedly promotes C2C12 myoblast differentiation. Therefore, we investigated the Sparc family gene expression during myogenesis in C2C12 myoblasts after cisplatin treatment. Of all the genes investigated, Sparc-like protein 1 (Sparcl1) expression was significantly suppressed by cisplatin on Days 4-8. Simultaneous treatment with recombinant mouse Sparcl1 almost inhibited the cisplatin-induced suppression of total MyHC and myogenin protein levels. Moreover, Sparcl1 expression decreased in the skeletal muscles of mice, leading to cisplatin-induced muscle atrophy. Our results suggest that cisplatin-induced myogenesis suppression causes muscle atrophy and inhibits the expression of Sparcl1, which promotes C2C12 cell differentiation during myogenesis.

Increased 20S Proteasome Expression and the Effect of Bortezomib during Cisplatin-Induced Muscle Atrophy.

Cisplatin is a chemotherapy drug used to treat a variety of cancers. Muscle loss in cancer patients is associated with increased cancer-related mortality. Previously, we suggested that cisplatin administration increases the atrophic gene expressions of ubiquitin E3 ligases, such as atrogin-1 and muscle RING finger-1 (MuRF1), which may lead to muscle atrophy. In this study, C57BL/6J mice were treated with cisplatin (3 mg/kg, intraperitoneally) or saline for 4 consecutive days. Twenty-four hours after the final injection of cisplatin, quadriceps muscles were removed from the mice. The gene expression of Psma and Psmb, which comprise the 20S proteasome, was upregulated by cisplatin administration in the quadriceps muscle of mouse. Systemic administration of cisplatin significantly reduced not only the quadriceps muscle mass but also the diameter of the myofibers. In addition, bortezomib (0.125 mg/kg, intraperitoneally) was administered 30 min before each cisplatin treatment. The co-administration of bortezomib, a proteasome inhibitor, significantly recovered the reductions in the mass of quadriceps and myofiber diameter, although it did not recover the decline in the forelimb and forepaw strength induced by cisplatin. Increased 20S proteasome abundance may play a significant role in the development of cisplatin-induced muscle atrophy. During cisplatin-induced skeletal muscle atrophy, different mechanisms may be involved between loss of muscle mass and strength. In addition, it is suggested that bortezomib has essentially no effect on cisplatin-induced muscle atrophy.

Inhibition of Spred/Sprouty Expression in the Skin of a Contact Dermatitis-Like Model.

We have previously reported that swellings caused by haptens, such as 2,4,6-trinitrochlorobenzene (TNCB), may be associated with the extracellular signal-regulated kinase (ERK)-induced proliferation pathway. However, the involvement of the Spred/Sprouty family as critical negative regulators of the Ras/Raf/ERK signaling pathway at disease sites is not well-established. Thus, in the present study, the effects of hapten-challenge on the expression levels of genes and proteins associated with the Spred/Sprouty family in the ear of mice were investigated. The activation of ERK and epidermal growth factor receptor (EGFR) tyrosine kinase was inhibited by their selective inhibitors, namely, U0126 and PD168393, respectively. Twenty-four hours after the final challenge by the haptens TNCB, 2,4-dinitrofluorobenzene, or oxazolone, ear thickness was augmented by challenge with all haptens and the gene expression levels of Spred1, Spred2, Sprouty1, and Sprouty2 in swelling induced by all haptens were significantly decreased. Furthermore, Spred2, Sprouty1, and Sprouty2 genes were decreased in the epidermis and dermis of the TNCB-challenged ear. In conclusion, it is possible that the mechanism of hapten-challenge-induced skin thickening involves not only the enhancement of cell proliferative functions via the activation of ERK by EGFR tyrosine kinase activation but also the decreases expression of Spred/Sprouty family members.

Exogenous insulin-like growth factor 1 attenuates cisplatin-induced muscle atrophy in mice.

BACKGROUND: A reduction in the skeletal muscle mass worsens the prognosis of patients with various cancers. Our previous studies indicated that cisplatin administration to mice caused muscle atrophy. This is a concern for human patients receiving cisplatin. The insulin-like growth factor 1 (IGF-1)/phosphoinositide 3-kinase (PI3K)/Akt pathway stimulates the rate of protein synthesis in skeletal muscle. Thus, IGF-I can be a central therapeutic target for preventing the loss of skeletal muscle mass in muscle atrophy, although it remains unclear whether pharmacological activation of the IGF-1/PI3K/Akt pathway attenuates muscle atrophy induced by cisplatin. In this study, we examined whether exogenous recombinant human IGF-1 attenuated cisplatin-induced muscle atrophy. METHODS: Male C57BL/6J mice (8-9 weeks old) were injected with cisplatin or saline for four consecutive days. On Day 5, quadriceps muscles were isolated. Mecasermin (recombinant human IGF-1) or the vehicle control was subcutaneously administered 30 min prior to cisplatin administration. A dietary restriction group achieving weight loss equivalent to that caused by cisplatin administration was used as a second control. C2C12 myotubes were treated with cisplatin with/without recombinant mouse IGF-1. The skeletal muscle protein synthesis/degradation pathway was analysed by histological and biochemical methods. RESULTS: Cisplatin reduced protein level of IGF-1 by about 85% compared with the vehicle group and also reduced IGF-1/PI3K/Akt signalling in skeletal muscle. Under this condition, the protein levels of muscle ring finger protein 1 (MuRF1) and atrophy gene 1 (atrogin-1) were increased in quadriceps muscles (MuRF1; 3.0 ± 0.1 folds, atrogin-1; 3.0 ± 0.3 folds, P < 0.001, respectively). The administration of a combination of cisplatin and IGF-1 significantly suppressed the cisplatin-induced downregulation of IGF-1/PI3K/Akt signalling and upregulation of MuRF1 and atrogin-1 (up to 1.6 ± 0.3 and 1.5 ± 0.4 folds, P < 0.001, respectively), resulting in diminished muscular atrophy. IGF-1 showed similar effects in cisplatin-treated C2C12 myotubes, as well as the quadriceps muscle in mice. CONCLUSIONS: The downregulation of IGF-1 expression in skeletal muscle might be one of the factors playing an important role in the development of cisplatin-induced muscular atrophy. Compensating for this downregulation with exogenous IGF-1 suggests that it could be a therapeutic target for limiting the loss of skeletal muscle mass in cisplatin-induced muscle atrophy.

Role of Cutaneous Aquaporins in the Development of Xeroderma in Type 2 Diabetes.

Xeroderma is induced by diabetes, reducing patients' quality of life. We aimed to clarify the roles of cutaneous water channel aquaporin-3 (AQP3) in diabetic xeroderma using type 2 diabetes model db/db mice. Blood glucose levels were unchanged in 5-week-old db/db mice compared to db/+ mice (control mice), but the pathophysiology of type 2 diabetes was confirmed in 12-week-old db/db mice. The dermal water content and AQP3 expression in 5-week-old db/db mice were almost the same as those in the control mice. On the other hand, in 12-week-old db/db mice, the dermal water content and AQP3 expression were significantly decreased. The addition of glucose to HaCaT cells had no effect on AQP3, but tumor necrosis factor-α (TNF-α) decreased the AQP3 expression level. Blood TNF-α levels or skin inflammation markers in the 12-week-old db/db mice were significantly higher than those in control mice. AQP3 levels in the skin were decreased in type 2 diabetes, and this decrease in AQP3 may be one of the causes of xeroderma. Therefore, a substance that increases AQP3 may be useful for improving xeroderma. Additionally, a decrease in skin AQP3 may be triggered by inflammation. Therefore, anti-inflammatory drugs may be effective as new therapeutic agents for diabetic xerosis.

Upregulation of ubiquitinated proteins and their degradation pathway in muscle atrophy induced by cisplatin in mice.

We previously demonstrated that cisplatin administration in mice induces muscle atrophy and an increase in the expression of two muscle-specific ubiquitin E3 ligase genes, muscle ring finger protein 1 (MuRF1), and atrophy gene-1 (atrogin-1), in skeletal muscle. Ubiquitination serves as a degradation signal in both the ubiquitin-proteasome and selective autophagy pathways. In the present study, we investigated changes in the expression of ubiquitin and ubiquitinated proteins and their degradation pathways. Ubiquitin and ubiquitinated protein levels were increased by cisplatin compared with those in the vehicle and dietary restriction (DR) groups. To quantify the levels of ubiquitin and ubiquitinated proteins, we conducted a dot blot assay using an anti-ubiquitin antibody. The expression of ubiquitin was also significantly increased by cisplatin compared with that in the vehicle and DR groups. Since the ubiquitin proteins were upregulated by cisplatin, we measured the mRNA levels of the ubiquitin genes: Ubb, Ubc, Rps27a, and Uba52. All these four genes were increased by cisplatin administration compared with those in both the vehicle-treated and DR groups in quadriceps muscle tissue. The anti-ubiquitin antibody-sensitive bands increased when C2C12 myotubes were treated with cisplatin. Furthermore, MG-132 (26 s proteasome inhibitor), but not bafilomycin A1 (autophagy inhibitor), caused a further increase in expression. In conclusion, ubiquitin and ubiquitinated proteins are upregulated in cisplatin-induced muscle atrophy. Cisplatin-induced ubiquitinated proteins are degraded by the 26 s proteasome pathway.

Lactobacillus helveticus-Fermented Milk Whey Suppresses Melanin Production by Inhibiting Tyrosinase through Decreasing MITF Expression.

Whey obtained from milk fermented by the Lactobacillus helveticus CM4 strain (LHMW) has been shown to improve skin barrier function and increase skin-moisturizing factors. In this study, we investigated the effects of LHMW on melanin production to explore the additional impacts of LHMW on the skin. We treated mouse B16 melanoma cells with α-melanocyte-stimulating hormone (α-MSH) alone or simultaneously with LHMW and measured the amount of melanin. The amount of melanin in B16 cells treated with α-MSH significantly increased by 2-fold compared with that in control cells, and tyrosinase activity was also elevated. Moreover, treatment with LHMW significantly suppressed the increase in melanin content and elevation of tyrosinase activity due to α-MSH. LHMW also suppressed the α-MSH-induced increased expression of tyrosinase, tyrosinase-related protein 1 (TRP1), and dopachrome tautomerase (DCT) at the protein and mRNA levels. Furthermore, the mRNA and protein microphthalmia-associated transcription factor (MITF) expression levels were significantly increased with treatment with α-MSH alone, which were also suppressed by LHMW addition. LHMW suppression of melanin production is suggested to involve inhibition of the expression of the tyrosinase gene family by lowering the MITF expression level. LHMW may have promise as a material for cosmetics with expected clinical application in humans.

A Mechanism by which Ergosterol Inhibits the Promotion of Bladder Carcinogenesis in Rats.

We previously showed that ergosterol has an inhibitory effect on bladder carcinogenesis. In this study, we aimed to elucidate the molecular mechanism by which ergosterol inhibits bladder carcinogenesis using a rat model of N-butyl-N-(4-hydroxybutyl)nitrosamine-induced bladder cancer. The messenger ribonucleic acid (mRNA) expression level of the cell cycle-related gene cyclin D1 and inflammation-related gene cyclooxygenase-2 in bladder epithelial cells was significantly increased in the carcinogenesis group compared with the control group. In contrast, in ergosterol-treated rats, these increases were significantly suppressed. Ergosterol did not affect the plasma testosterone concentration or the binding of dihydrotestosterone to androgen receptor (AR). The mRNA expression levels of 5α-reductase type 2 and AR were higher in the carcinogenesis group than in the control group but were significantly decreased by ergosterol administration. These results suggest that ergosterol inhibits bladder carcinogenesis by modulating various aspects of the cell cycle, inflammation-related signaling, and androgen signaling. Future clinical application of the preventive effect of ergosterol on bladder carcinogenesis is expected.

Inhibitory effect of ergosterol on bladder carcinogenesis is due to androgen signaling inhibition by brassicasterol, a metabolite of ergosterol.

We previously revealed that Choreito, a traditional Kampo medicine, strongly inhibits bladder carcinogenesis promotion. We have also shown that Polyporus sclerotium, which is one of the crude drugs in Choreito, has the strongest bladder carcinogenesis inhibitory effect and that the ergosterol contained in Polyporus sclerotium is the main active component. In this study, we analyzed the mechanism by which ergosterol inhibits bladder carcinogenesis. Rats were given an N-butyl-N-(4-hydroxybutyl) nitrosamine (BHBN) solution ad libitum, and then a promoter [saccharin sodium (SS), DL-tryptophan, or BHBN] was administered together with ergosterol or its metabolite, brassicasterol. The bladders were removed from rats, and the inhibitory effect on carcinogenesis promotion was evaluated by an agglutination assay with concanavalin A (Con A). Although the oral administration of ergosterol inhibited the promotion of bladder carcinogenesis with SS, the intraperitoneal administration of brassicasterol showed a stronger effect. The effect of brassicasterol on carcinogenesis promotion was observed regardless of the type of promoter. Administration of testosterone to castrated rats increased the number of cell aggregates caused by Con A. In contrast, intraperitoneal administration of brassicasterol to castrated rats treated with testosterone significantly decreased the number of cell aggregates, confirming the inhibition of bladder carcinogenesis promotion. The inhibitory effect of ergosterol on bladder carcinogenesis is due to brassicasterol, a metabolite of ergosterol. The action of brassicasterol via androgen signaling may play a role in the inhibitory effect on bladder carcinogenesis promotion.

Acacia Polyphenol Ameliorates Atopic Dermatitis in Trimellitic Anhydride-Induced Model Mice via Changes in the Gut Microbiota.

We have previously shown that acacia polyphenol (AP), which was extracted from the bark of Acacia mearnsii De Wild, exerts antiobesity, antidiabetic, and antihypertensive effects. In this study, we examined the effect of AP on atopic dermatitis. Trimellitic anhydride (TMA) was applied to the ears of mice to create model mice with atopic dermatitis. The frequency of scratching behavior in the TMA-treated group was significantly higher than that in the control group, and the expression levels of inflammatory markers (tumor necrosis factor-α, interleukin-6, inducible nitric oxide synthase, and cyclooxygenase-2) in the skin also increased. In contrast, both the frequency of scratching behavior and the expression levels of skin inflammatory markers in the AP-treated group were significantly lower than those in the TMA-treated group. The abundances of beneficial bacteria, such as Bifidobacterium spp. and Lactobacillus spp., increased in the AP-treated group compared with the TMA-treated group. Furthermore, the abundances of Bacteroides fragilis and Clostridium coccoides in the gut, which are known for anti-inflammatory properties, increased significantly with AP administration. The present results revealed that AP inhibits TMA-induced atopic dermatitis-like symptoms. In addition, the results also suggested that this effect may be associated with the mechanism of gut microbiota improvement.

Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Erlotinib Induces Dry Skin via Decreased in Aquaporin-3 Expression.

An adverse reaction of dry skin occurs frequently during treatment with anticancer epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). In this study, we conducted basic research to clarify the mechanism of EGFR-TKI-induced dry skin and propose new treatments or preventative measures. Dermal water content was significantly lower in the erlotinib-treated mice than in the control group. An assessment of the expression levels of functional genes in the skin revealed that only the expression of the water channel aquaporin-3 (AQP3) was significantly decreased in the erlotinib-treated group. When erlotinib was added to epidermal keratinocyte HaCaT cells, the expression levels of both AQP3 mRNA and protein decreased. Erlotinib treatment also significantly decreased the expression levels of phospho-EGFR and phospho-extracellular signal-regulated kinase (ERK), both in HaCaT cells and mouse skin. Dry skin due to erlotinib may be caused by the decreased expression of AQP3 in the skin, thereby limiting water transport from the vascular side to the corneum side. The decrease in AQP3 may also be attributable to ERK suppression via inhibition of EGFR activity by erlotinib. Therefore, substances that increase AQP3 expression may be effective for erlotinib-induced dry skin.

Interference of Skin Scratching Attenuates Accumulation of Neutrophils in Murine Allergic Contact Dermatitis Model.

We recently reported that swelling resulting from 2,4,6-trinitrochlorobenzene (TNCB) challenge might be associated with recruitment of neutrophils. However, it is not known whether neutrophil recruitment is affected by scratching at inflamed sites or not. Therefore, the effects of an Elizabethan collar on the TNCB-induced upregulation of ELR-positive chemokines (CXCL1, CXCL2, and CXCL5) and neutrophil recruitment were investigated. Mice were sensitized by the application of TNCB on abdominal skin. Then, the mice were challenged three times with TNCB to auricle of the ear. To prevent scratching at inflamed sites, an Elizabethan collar was placed on the mice from just before the first challenge until the end of the experiment. The effects of the Elizabethan collar on the TNCB-induced upregulation of CXCLs chemokines and recruitment of neutrophil were investigated. The increase of ear swelling by TNCB challenge was inhibited by the Elizabethan collar. TNCB-challenge-induced upregulation of TNF-α, IL-1ß, IL-6, ELR+ chemokines, MPO, and ELA2 was also attenuated by the Elizabethan collar. The gene expression of CXCL1, CXCL2, and CXCL5 human homolog IL-8 was enhanced by TNF-α and IL-1ß in human dermal fibroblasts and epidermal keratinocytes. We here suggest that scratching the site of inflammation leads to neutrophil accumulation mediated by TNF-α and IL-1ß/ELR+ chemokines in TNCB-challenge-induced contact dermatitis in mice.

Increased Rac1 Activation in the Enhanced Carbachol-Induced Bronchial Smooth Muscle Contraction of Repeatedly Antigen-Challenged Mice.

Recently, we demonstrated that Rac1 upregulation is involved in augmented bronchial smooth muscle (BSM) contractions of antigen-challenged mice. However, change in G protein-coupled receptor (GPCR)-induced Rac1 activation remains unknown in BSMs of repeatedly antigen-challenged (Chal.) mice. We here examined carbachol (CCh)-induced Rac1 activation in BSMs of Chal. mice. Gene expression levels of both Rac1 and Rac-guanine nucleotide exchange factors (GEFs), such as Tiam1 and Trio, were increased in BSMs of Chal. mice. Furthermore, CCh-induced Rac1 activation was inhibited by pretreatment with Rac1-GEF inhibitor NSC23766 and Rac1 inhibitor EHT1864 in BSMs of sensitized-control (S.C.) and Chal. mice. Compared with S.C. mice, CCh-induced Rac1 activation was increased in BSMs of Chal. mice. In conclusion, we reported that increased CCh-induced Rac1 activation via Tiam1 and Trio upregulation, in addition to upregulate Rac1, may be involved in increased CCh-induced BSM contractions in Chal. mice.

Dexamethasone exacerbates cisplatin-induced muscle atrophy.

Dexamethasone for antiemetic therapy is typically administered with anticancer drugs such as cisplatin. We previously reported that cisplatin upregulates the muscle-specific E3 ubiquitin ligase genes, namely muscle ring-finger protein 1 (MuRF1) and atrophy gene-1 (atrogin-1), and promotes muscle atrophy in mice. It is well known that dexamethasone causes upregulation of MuRF1 and Atrogin-1 expression in skeletal muscles. Although it is speculated that a combination of dexamethasone and cisplatin worsens muscle atrophy, there are no reports based on research. We thereby investigated the effects of cisplatin and dexamethasone, alone or in combination, on the expression of MuRF1 and Atrogin-1 in murine skeletal muscles and C2C12 myotubes. Mice were intraperitoneally injected with cisplatin or the vehicle control once daily for 4 days. Dexamethasone or the vehicle control was subcutaneously administered 30 minutes prior to the administration of cisplatin. Dexamethasone enhanced MuRF1 and Atrogin-1 gene expression upregulated by cisplatin in murine quadriceps muscles and C2C12 myotubes. Cisplatin-caused upregulation of myostatin and downregulation of IGF-1 gene expression were also enhanced by co-administration of dexamethasone in murine quadriceps muscles and C2C12 myotubes. This study shows that the combination treatment of cisplatin and dexamethasone exacerbated muscle atrophy in mice. Therefore, this treatment regimen might exacerbate muscle atrophy in cancer patients.

Anti-Hypertensive Effects of Acacia Polyphenol in Spontaneously Hypertensive Rats.

We have previously demonstrated that acacia polyphenol (AP) exerts strong anti-obesity, anti-diabetic, and anti-atopic dermatitis effects. In the present study, we investigated the anti-hypertensive effects of AP. Spontaneously hypertensive rats (SHR) with hypertension and control Wistar Kyoto rats (WKY) were used. WKY and SHR were fed AP-containing food or AP-free food (control group) ad libitum for 4 weeks, and their blood pressures were measured. After AP administration, both systolic and diastolic blood pressures were significantly lower in the SHR group than in the control group. There were no differences in the systolic or diastolic blood pressure of WKY between the AP group and the control group. Angiotensin-converting enzyme (ACE) activity, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression, and superoxide dismutase (SOD) activity in SHR kidneys were not altered by AP administration. Blood SOD activity in SHR was significantly higher in the AP group than in the control group. AP exerts anti-hypertensive effects on hypertension but has almost no effect on normal blood pressure. The anti-hypertensive effects of AP may be related to the anti-oxidative effects of increased blood SOD activity.

CPT-11-Induced Delayed Diarrhea Develops via Reduced Aquaporin-3 Expression in the Colon.

While irinotecan (CPT-11) has a potent anti-cancer effect, it also causes serious diarrhea as an adverse reaction. In this study, we analyzed the pathogenic mechanism of CPT-11-induced delayed diarrhea by focusing on water channel aquaporin-3 (AQP3) in the colon. When rats received CPT-11, the expression level of AQP3 was reduced during severe diarrhea. It was found that the expression levels of inflammatory cytokines and the loss of crypt cells were increased in the colon when CPT-11 was administered. When celecoxib, an anti-inflammatory drug, was concomitantly administered, both the diarrhea and the reduced expression of AQP3 induced by CPT-11 were suppressed. The inflammation in the rat colon during diarrhea was caused via activated macrophage by CPT-11. These results showed that when CPT-11 is administered, the expression level of AQP3 in the colon is reduced, resulting in delayed diarrhea by preventing water transport from the intestinal tract. It was also suggested that the reduced expression of AQP3 might be due to the inflammation that occurs following the loss of colonic crypt cells and to the damage caused by the direct activation of macrophages by CPT-11. Therefore, it was considered that anti-inflammatory drugs that suppress the reduction of AQP3 expression could prevent CPT-11-induced delayed diarrhea.

Epigallocatechin gallate induces a hepatospecific decrease in the CYP3A expression level by altering intestinal flora.

In previous studies, we showed that a high-dose intake of green tea polyphenol (GP) induced a hepatospecific decrease in the expression and activity of the drug-metabolizing enzyme cytochrome P450 3A (CYP3A). In this study, we examined whether this decrease in CYP3A expression is induced by epigallocatechin gallate (EGCG), which is the main component of GP. After a diet containing 1.5% EGCG was given to mice, the hepatic CYP3A expression was measured. The level of intestinal bacteria of Clostridium spp., the concentration of lithocholic acid (LCA) in the feces, and the level of the translocation of pregnane X receptor (PXR) to the nucleus in the liver were examined. A decrease in the CYP3A expression level was observed beginning on the second day of the treatment with EGCG. The level of translocation of PXR to the nucleus was significantly lower in the EGCG group. The fecal level of LCA was clearly decreased by the EGCG treatment. The level of intestinal bacteria of Clostridium spp. was also decreased by the EGCG treatment. It is clear that the hepatospecific decrease in the CYP3A expression level observed after a high-dose intake of GP was caused by EGCG. Because EGCG, which is not absorbed from the intestine, causes a decrease in the level of LCA-producing bacteria in the colon, the level of LCA in the liver decreases, resulting in a decrease in the nuclear translocation of PXR, which in turn leads to the observed decrease in the expression level of CYP3A.