Translating dosimetry of Dibenzo[def,p]chrysene (DBC) and metabolites across dose and species using physiologically based pharmacokinetic (PBPK) modeling.

Dibenzo[def,p]chrysene (DBC) is an environmental polycyclic aromatic hydrocarbon (PAH) that causes tumors in mice and has been classified as a probable human carcinogen by the International Agency for Research on Cancer. Animal toxicity studies often utilize higher doses than are found in relevant human exposures. Additionally, like many PAHs, DBC requires metabolic bioactivation to form the ultimate toxicant, and species differences in DBC and DBC metabolite metabolism have been observed. To understand the implications of dose and species differences, a physiologically based pharmacokinetic model (PBPK) for DBC and major metabolites was developed in mice and humans. Metabolism parameters used in the model were obtained from experimental in vitro metabolism assays using mice and human hepatic microsomes. PBPK model simulations were evaluated against mice dosed with 15 mg/kg DBC by oral gavage and human volunteers orally microdosed with 29 ng of DBC. DBC and its primary metabolite DBC-11,12-diol were measured in blood of mice and humans, while in urine, the majority of DBC metabolites were obeserved as conjugated DBC-11,12-diol, conjugated DBC tetrols, and unconjugated DBC tetrols. The PBPK model was able to predict the time course concentrations of DBC, DBC-11,12-diol, and other DBC metabolites in blood and urine of human volunteers and mice with reasonable accuracy. Agreement between model simulations and measured pharmacokinetic data in mice and human studies demonstrate the success and versatility of our model for interspecies extrapolation and applicability for different doses. Furthermore, our simulations show that internal dose metrics used for risk assessment do not necessarily scale allometrically, and that PBPK modeling provides a reliable approach to appropriately account for interspecies differences in metabolism and physiology.

Oral administration of cystine and theanine attenuates 5-fluorouracil-induced intestinal mucositis and diarrhea by suppressing both glutathione level decrease and ROS production in the small intestine of mucositis mouse model.

BACKGROUND: Chemotherapy is frequently used in cancer treatment; however, it may cause adverse events, which must be managed. Reactive oxygen species (ROS) have been reported to be involved in the induction of intestinal mucositis and diarrhea, which are common side effects of treatment with fluoropyrimidine 5-fluorouracil (5-FU). Our previous studies have shown that oral administration of cystine and theanine (CT) increases glutathione (GSH) production in vivo. In the present study, we hypothesized that CT might inhibit oxidative stress, including the overproduction of ROS, and attenuate 5-FU-induced mucositis and diarrhea. METHODS: We investigated the inhibitory effect of CT administration on mucositis and diarrhea, as well as its mechanism, using a mouse model of 5-FU-induced intestinal mucositis. RESULTS: CT administration suppressed 5-FU-induced diarrhea and weight loss in the studied mice. After 5-FU administration, the GSH level and the GSH/GSSG ratio in the small intestine mucosal tissue decreased compared to normal control group; but CT administration improved the GSH/GSSG ratio to normal control levels. 5-FU induced ROS production in the basal region of the crypt of the small intestine mucosal tissue, which was inhibited by CT. CT did not affect the antitumor effect of 5-FU. CONCLUSIONS: CT administration suppressed intestinal mucositis and diarrhea in a mouse model. This finding might be associated with the antioxidant characteristics of CT, including the improved rate of GSH redox and the reduced rate of ROS production in the small intestine mucosal tissue. CT might be a suitable candidate for the treatment of gastrointestinal mucositis associated with chemotherapy.

Gold nanoparticle synthesis in contact lenses for drug-less ocular cystinosis treatment.

PURPOSE: To develop gold nanoparticles-loaded contact lens ("GoldinLens") to bind a significant mass of cystine on the surface of the gold nanoparticles (GNPs) for cystinosis treatment due to the reaction between cystine and gold. METHODS: The GoldinLens was manufactured by synthesizing GNPs inside the preformed contact lens matrix by first loading the lenses (Moist and TrueEye) with gold precursor followed by reduction (with sodium borohydride or trisodium citrate) to gold atoms, which nucleated to GNPs inside the polymeric matrix. The lenses were characterized by SEM, XRD, UV-Vis spectroscopy and mass of GNPs loaded in the lens was determined by direct measurement of mass. Manufactured lenses were soaked in cystine solution for cystine uptake in vitro. RESULTS: Results show that gold loading in the contact lens increases linearly with gold precursor concentration and number of repetitions of the manufacturing process. The stronger reducing agent sodium borohydride resulted in higher gold loading, with the loading being higher in the Moist lenses due to higher diffusivity of the reducing agent into the lens. However, GNPs were smaller in size and relatively monodispersed in TruEye GoldinLens, resulting in higher cystine uptake of 47 µg/lens over 24 h (vs. 33 µg/lens for Moist GoldinLens). However, the rate of this uptake was higher for Moist GoldiLens (8.25 vs. 2.35 µg/h), with the maximum uptake occurring in one hour (vs. five hours). CONCLUSION: A method for manufacturing GoldinLens, wherein small gold nanoparticles are trapped in contact lenses, has been developed for drugless cystinosis treatment. The lenses withdraw cystine molecules from the surrounding milieu, with the TrueEye GoldinLens being superior for the extent of, while Moist GoldinLens is superior for rate of cystine removal. GoldinLenses of this study can be used for drugless cystine removal cystinosis treatment with one- or five-hour wear at a time.

Optimal methionine plus cystine requirements in diets supplemented with L-methionine in starter, grower, and finisher broilers.

Correct supplementation of dietary amino acids, such as methionine (Met) and cystine (Cys), is crucial to support the exponential growth of broilers. Historically, most available recommendations with regard to the optimal amount of Met plus Cys are based on studies wherein DL-Met was used as the Met source. Nowadays, L-Met is available as a registered feed additive, urging the need to establish the optimal L-Met plus Cys supplementation. The objective of this trial was to investigate these optimal L-Met plus Cys requirements of broilers in the starter (0-10 d), grower (11-23 d), and finisher (24-35 d) phase of life separately. A basal diet deficient in L-Met plus Cys was created along with 6 other diets with increasing L-Met concentrations for each phase. Birds were only included in one life phase and fed with a commercial diet before inclusion. The BW, daily weight gain, daily feed intake, and feed conversion ratio (gain-to-feed ratio) were measured for all birds. Slaughter parameters were determined for birds included in the finisher phase. At the end of each study period, significant differences (P < 0.05) were observed in all measured performance parameters. Birds fed with the deficient diets were characterized by a lower performance, whereas from some point, no gain in performance could be observed. Correct supplementation of L-Met plus Cys seemed more crucial in the starter and grower phase, which was characterized by bigger differences in performance between test diets compared with the finisher birds. The optimal L-Met plus Cys requirements were determined using linear broken line and exponential asymptotic models. The linear broken line model showed overall the best fit. The optimal L-Met plus Cys level was found to be 0.69, 0.66, and 0.62% for birds in the starter, grower, and finisher phase, respectively. From this study, it could be concluded that broilers have lower L-Met plus Cys requirements based on L-Met supplementation than the conventional requirements based on DL-Met. Nevertheless, further research is required to confirm these findings.

Glutamine and cystine-enriched diets modulate aquaporins gene expression in the small intestine of piglets.

The regulation of glycerol permeability in the gastrointestinal tract is crucial to control fat deposition, lipolysis and gluconeogenesis. Knowing that the amino acid glutamine is a physiological regulator of gluconeogenesis, whereas cystine promotes adiposity, herein we investigated the effects of dietary supplementation with glutamine and cystine on the serum biochemical parameters of piglets fed on amino acid-enriched diets, as well as on the transcriptional profile of membrane water and glycerol channels aquaporins (AQPs) in the ileum portion of the small intestine and its impact on intestinal permeability. Twenty male piglets with an initial body weight of 8.8 ± 0.89 kg were allocated to four dietary treatments (n = 5) and received, during a four week-period, a basal diet without supplementation (control) or supplemented with 8 kg/ton of glutamine (Gln), cystine (Cys) or the combination of the two amino acids in equal proportions (Gln + Cys). Most biochemical parameters were found improved in piglets fed Gln and Cys diet. mRNA levels of AQP3 were found predominant over the others. Both amino acids, individually or combined, were responsible for a consistent downregulation of AQP1, AQP7 and AQP10, without impacting on water permeability. Conversely, Cys enriched diet upregulated AQP3 enhancing basolateral membranes glycerol permeability and downregulating glycerol kinase (GK) of intestinal cells. Altogether, our data reveal that amino acids dietary supplementation can modulate intestinal AQPs expression and unveil AQP3 as a promising target for adipogenesis regulation.

Cystine and Theanine as Stress-Reducing Amino Acids-Perioperative Use for Early Recovery after Surgical Stress.

Perioperative nutritional therapy requires the consideration of metabolic changes, and it is desirable to reduce stress aiming at early metabolic normalization. Glutathione (GSH) is a tripeptide composed of glutamic acid, cysteine, and glycine. It is one of the strongest antioxidants in the body and important for adjusting immune function. Cystine and theanine (γ-glutamylethylamide) provide substrates of GSH, cysteine and glutamic acid, promoting the synthesis of GSH. It has been reported that the ingestion of cystine (700 mg) and theanine (280 mg) exhibits inhibitory effects against excess inflammation after strong exercise loads in athletes, based on which its application for invasive surgery has been tried. In patients undergoing gastrectomy, ingestion of cystine (700 mg) and theanine (280 mg) for 10 days from 5 days before surgery inhibited a postoperative increase in resting energy expenditure, promoted recovery from changes in interleukin-6, C-reactive protein, lymphocyte ratio, and granulocyte ratio and inhibited an increase in body temperature. In a mouse small intestine manipulation model, preoperative 5-day administration of cystine/theanine inhibited a postoperative decrease in GSH in the small intestine and promoted recovery from a decrease in behavior quantity. Based on the above, cystine/theanine reduces surgical stress, being useful for perioperative management as stress-reducing amino acids.

Modelling of sulphur amino acid requirements and nitrogen endogenous losses in kittens.

The objective of this study was to estimate the sulphur amino acid (methionine + cystine) requirements and nitrogen endogenous losses in kittens aged 150 to 240 d. Thirty-six cats were distributed in six treatments (six cats per treatment) consisting of different concentrations of methionine + cystine (M + C): T1, 6.5 g/kg; T2, 8.8 g/kg; T3, 11.3 g/kg; T4, 13.6 g/kg; T5, 16.0 g/kg; and control, 6.5 g/kg. Diets were formulated by serial dilution of T5 (a diet relatively deficient in M + C but containing high protein concentrations) with a minimal nitrogen diet (MND). Thus, crude protein and amino acid concentrations in diets T1-T5 decreased by the same factor. The control diet was the T1 diet supplemented with adequate concentrations of M + C (6.5 g/kg; 8.8 g/kg; 11.3 g/kg; 13.6 g/kg and 16.0 g/kg). All diets were based on ingredients commonly used in extruded cat diets. Digestibility assays were performed for the determination of nitrogen balance. Nitrogen intake (NI) and nitrogen excretion (NEX) results data were fitted with an exponential equation to estimate nitrogen maintenance requirement (NMR), theoretical maximum for daily nitrogen retention (NRmaxT), and protein quality (b). M + C requirements were calculated from the limiting amino acid intake (LAAI) equation assuming a nitrogen retention of 45 to 65% NRmaxT. The NMR of kittens aged 150, 195, and 240 d was estimated at 595, 559, and 455 mg/kg body weight (BW)0.67 per day, respectively, and M + C requirements were estimated at 517, 664, and 301 mg/kg BW0.67 per day, respectively.

Oral administration of Cystine and Theanine ameliorates oxaliplatin-induced chronic peripheral neuropathy in rodents.

Oxaliplatin frequently causes severe peripheral neuropathy as a dose-limiting toxicity. However, this toxicity lacks a strategy for prevention. Cystine/Theanine is a supplement, which includes precursors for the biosynthesis of glutathione. In this study, we investigated the effects of Cystine/Theanine on oxaliplatin-induced peripheral neuropathy using an in vivo model. Repeated injection of oxaliplatin (4 mg/kg intraperitoneally twice a week for 2 weeks) caused mechanical allodynia, cold hyperalgesia and axonal degeneration of the sciatic nerve in rats. Mechanical allodynia and axonal degeneration, but not cold hyperalgesia, were ameliorated by daily co-administration of Cystine [200 mg/kg orally (p.o.)] and Theanine (80 mg/kg p.o.). Moreover, co-administration of Cystine and Theanine to rats significantly increased the glutathione level in the sciatic nerve compared with the oxaliplatin group. Furthermore, Cystine and Theanine did not attenuate the tumour cytotoxicity of oxaliplatin in C-26 tumour cell-bearing mice. These findings suggest that Cystine and Theanine may be beneficial for preventing oxaliplatin-induced peripheral neuropathy.

Protective effect of the oral administration of cystine and theanine on oxaliplatin-induced peripheral neuropathy: a pilot randomized trial.

BACKGROUND: Oxaliplatin, one of the key cytotoxic drugs for colorectal cancer, frequently causes peripheral neuropathy which leads to dose modification and decreased patients' quality of life. However, prophylactic or therapeutic measures have not yet been established. Orally administered amino acids, cystine and theanine, promoted the synthesis of glutathione which was one of the potential candidates for preventing the neuropathy. The aim of this study was to determine whether daily oral administration of cystine and theanine attenuated oxaliplatin-induced peripheral neuropathy (OXLIPN). METHODS: Twenty-eight colorectal cancer patients who received infusional 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) therapy were randomly and evenly assigned to the cystine and theanine group and the control group. OXLIPN was assessed up to the sixth course using original 7-item questionnaire as well as Common Terminology Criteria for Adverse Events (CTCAE) grading scale. RESULTS: Neuropathy scores according to our original questionnaire were significantly smaller in the cystine and theanine group at the fourth (p = 0.026), fifth (p = 0.029), and sixth course (p = 0.038). Furthermore, significant differences were also observed in CTCAE neuropathy grades at the fourth (p = 0.037) and the sixth course (p = 0.017). There was one patient in each group who required dose reduction due to OXLIPN. Except for neurotoxicity, no significant differences were noted in the incidence of adverse events, and the total amount of administered oxaliplatin. CONCLUSION: The results demonstrated the daily oral administration of cystine and theanine attenuated OXLIPN.

Dietary Cystine Ameliorates Defects in Spermatogenesis via Testosterone Production Induced by Protein Deficiency and Darkness in Rats.

Nutrition and light-dark cycle influence rat testicular development. With 9% casein diet (low protein diet) under normal 12 h-12 h lighting cycles (9P), juvenile rat testes undergo normal growth. On the other hand, a low protein diet with constant darkness (D9P) results in a growth arrest of rat testes. Supplementation of cystine to the low protein diet under constant darkness (D9PC) had a tendency to increase testes weight, suggesting an improvement in growth suppression. Whether the growth suppression of testes in D9P is associated with suppression of spermatogenesis has not yet been shown. We aimed to determine the effect of a low protein diet and constant darkness with or without dietary cystine in testes using a histological technique. In the histological assessment, D9P testes showed a decreased number of seminiferous tubules with elongated spermatids, indicating a functional testicular defect in this group. However, cystine supplementation resulted in enhanced spermatogenesis versus control animals (D9PC vs. D9P) implying the importance of cystine to testicular development in this condition. Furthermore, serum testosterone concentration was increased in D9PC suggesting contribution of testosterone to ameliorate spermatogenesis. From these results, we conclude that cystine supplementation to a low protein diet under constant darkness promoted an increase in testosterone which in turn benefitted spermatogenesis.

Efficiency of methionine and cystine utilization by broiler chickens using stable isotopes.

The aim of this study was to develop a method to determine the efficiency of utilization of Met and Cys using stable isotopes in order to reduce the number of sacrificed animals relative to the comparative slaughter technique. Met and Cys efficiencies were obtained separately and as total SAA values. Twenty-one 14- to 28-day-old broiler chickens were fed experimental diets containing different Met:Cys ratios (44:56, 50:50 and 56:44). Birds were given diets with daily supplements of L-(15 N) Met (60 mmol/kg) or L-(15 N2 ) Cys (35 mmol/kg) throughout the entire experimental period. Excreta were collected daily, and birds were euthanized at the end of the trial to collect feather-free bodies and feathers. Samples were analysed for 15 N and 15 N-Met content. The utilization efficiency for Met, Cys and Met + Cys for feather-free bodies was 55%, 75%, and 60%, while the efficiencies for feathers were estimated at 96%, 77% and 84% respectively.

Clinical and Pathological Benefit of Twendee X in Alzheimer's Disease Transgenic Mice with Chronic Cerebral Hypoperfusion.

BACKGROUND: Multiple pathogeneses are involved in Alzheimer's disease (AD), such as amyloid-ß accumulation, neuroinflammation, and oxidative stress. The pathological impact of chronic cerebral hypoperfusion on Alzheimer's disease is still poorly understood. METHODS: APP23 mice were implanted to bilateral common carotid arteries stenosis with ameroid constrictors for slowly progressive chronic cerebral hypoperfusion (CCH). The effects of the administration of Twendee X (TwX) were evaluated by behavioral analysis, immunohistochemical analysis, and immunofluorescent histochemistry. RESULTS: In the present study, chronic cerebral hypoperfusion, which is commonly found in aged Alzheimer's disease, significantly exacerbated motor dysfunction of APP23 mice from 5 months and cognitive deficit from 8 months of age, as well as neuronal loss, extracellular amyloid-ß plaque and intracellular oligomer formations, and amyloid angiopathy at 12 months. Severe upregulations of oxidative markers and inflammatory markers were found in the cerebral cortex, hippocampus, and thalamus at 12 months. Twendee X treatment (20 mg/kg/d, from 4.5 to 12 months) substantially rescued the cognitive deficit and reduced the above amyloid-ß pathology and neuronal loss, alleviated neuroinflammation and oxidative stress. CONCLUSIONS: The present findings suggested a potential therapeutic benefit of Twendee X for Alzheimer's disease with chronic cerebral hypoperfusion.

Cystine and Theanine Improve Survival after Gut Ischemia-Reperfusion.

BACKGROUND AND AIM: Oral administration of cystine and theanine (CT) may modulate antioxidant glutathione (GSH) metabolism, thereby improving outcomes after gut ischemia reperfusion. METHODS: Experiment 1: Institute of Cancer Research mice (n = 35) were assigned to a Vehicle (n = 11), a CT140 (n = 14), or a CT280 (n = 10) group. The CT140 and 280 groups were given CT at respective dosages of 140 and 280 mg/kg (cystine: theanine = 5: 2) once daily via gavage for 5 days. All mice underwent 75-min occlusion of the superior mesenteric artery (SMA). Survival after reperfusion was observed. Experiment 2: Mice (n = 67) were pretreated for 5 days (Vehicle: n = 24, CT280: n = 20, vehicle/sham: n = 23). The Vehicle and CT280 groups underwent 60-min SMA occlusion. Levels of GSH, the oxidized form of GSH, Glutathione-S-S-Glutathione (GSSG), and GSH-related amino acids (cysteine and glutamic acid) in the small intestine, and plasma cytokine (IL-6, IL-1ß, TNFα) levels, were evaluated before (0 h), 3, 6, or 9 h after reperfusion. RESULTS: Experiment 1: The CT280 group showed significantly better survival than the Vehicle group. Experiment 2: Gut GSSG, cysteine, and glutamic acid levels were higher in the CT280 than in the Vehicle group after reperfusion. Plasma IL-6 and TNFα levels rose more rapidly in the CT280 than in the Vehicle group. CONCLUSION: Oral administration of CT improves survival after gut I/R, possibly through the modulation of the GSH-redox cycle and cytokine responses.

Efficacy of oral administration of cystine and theanine in patients with colorectal cancer undergoing capecitabine-based adjuvant chemotherapy after surgery: study protocol for a multi-institutional, randomised, double-blinded, placebo-controlled, phase II trial.

INTRODUCTION: Although adjuvant capecitabine therapy for patients with colorectal cancer after surgery often causes adverse events (AEs), such as diarrhoea, stomatitis, anorexia and hand-foot syndrome (HFS), there are no standard prevention therapies. Cystine and theanine were reported to attenuate some chemotherapy-associated AEs, and are also expected to attenuate the AEs caused by capecitabine treatment. Therefore, our present study aimed to determine the safety and efficacy of cystine/theanine therapy in patients with colorectal cancer undergoing capecitabine-based adjuvant chemotherapy after surgery. METHODS AND ANALYSIS: A multi-institutional, prospective, randomised, double-blinded, placebo-controlled, phase II trial is being planned. Patients with colorectal cancer treated with capecitabine as an adjuvant chemotherapy will be randomised into either the cystine/theanine group (n=50) or placebo group (n=50). Data will be collected during four courses of capecitabine therapy. The primary endpoint will be incidence rate of diarrhoea of grade 1 or higher in accordance with the Common Terminology Criteria for AEs (CTCAE) v.4.0, Japanese Clinical Oncology Group (JCOG) version. The secondary endpoints are incidence rates of other AEs (CTCAE v.4.0-JCOG), scores of the Japanese version of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire module for all patients with cancer (QLQ-C30) and for patients with colorectal cancer (QLQ-CR29), incidence rate of HFS according to the HFS grading scale, protocol adherence, completion rate of four courses of capecitabine therapy and the proportion of completion without delay or dose reduction, time to completion of four courses of capecitabine and total dose of capecitabine. A sample size of 100 patients will be analysed between November 2016 and April 2018. ETHICS AND DISSEMINATION: Ethical approval was obtained at all participating institutions. The results of this study will be submitted for publication in international peer-reviewed journals. TRIAL REGISTRATION NUMBER: UMIN000024784; Pre-results.

Metionina+cistina digestível para juvenis de tambaqui / Digestible methionine+cystine for tambaqui juveniles

Avaliou-se o efeito dos níveis de metionina+cistina digestível para juvenis de tambaqui na fase inicial de desenvolvimento (3,03±0,06g) durante 45 dias. Foram utilizados 160 juvenis de tambaqui distribuídos em DIC, com cinco tratamentos (níveis de metionina+cistina digestível = 0,66; 0,73; 0,80; 0,87; 0,94%), quatro repetições e oito animais por unidade experimental. As dietas utilizadas foram isoproteicas (25%) e isoenergéticas (3200kcal.kg-1). Os resultados obtidos foram submetidos aos testes de homogeneidade, normalidade, à análise de variância e à análise de regressão. Os parâmetros físicos e químicos da água do sistema de recirculação ficaram dentro da faixa de tolerância para a espécie. Os níveis de metionina+cistina digestíveis avaliados não influenciaram (P>0,05) a sobrevivência, o índice hepatossomático, o índice de gordura visceral e o consumo de ração. Entretanto, ganho de peso e taxa de eficiência proteica apresentaram aumento linear (P<0,05) com aumento da metionina + cistina na ração. Verificou-se que os níveis de metionina + cistina para o tambaqui não foram completamente atendidos, sendo recomendada a realização de novos estudos.(AU)

This study aimed to determine digestible methionine+cystine requirement of tambaqui juveniles in the early stage of development (3.03 ± 0.06 g) lasting 45 days. 160 tambaqui juveniles were distributed into DIC, with five treatments (methionine + cystine = 0.66; 0.73; 0.80; 0.87; 0.94%), four replications and eight animals per experimental unit. The basal diets were isonitrogenous (25% crude protein) and isocaloric (3200kcal.kg-1). The results were submitted to the homogeneity test, normality test, analysis of variance, and regression analysis. The physical and chemical parameters of water from the water recirculation system were within those recommended for the species. Digestible methionine+cystine levels did not influence (P>0.05) the survival, hepatosomatic index, visceral fat index and feed intake. However, weight gain and protein efficiency ratio exhibit a linear increase (P<0.05) with increase in methionine and cystine in the feed. Our results showed that the methionine + cystine levels for tambaqui were not fully met, and new studies are recommended.(AU)

Nanohydrogel with N,N'-bis(acryloyl)cystine crosslinker for high drug loading.

Substantially improved hydrogel particles based on poly(N-isopropylacrylamide) (pNIPA) have been obtained. First, as a result of replacing commercially available N,N'-bis(acryloyl)cystamine (BAC), the crosslinker, with acryloyl derivative of cystine containing a carboxylic group (BISS), the hydrogel particles acquired improved stability vs. ionic strength and allowed further chemical modification of the chains, including the attachment of drug molecules. Next, a redox-initiated aqueous precipitation polymerization via the semi-batch method was used. This led to substantially increased BISS content and diminished size of the nanoparticles that made them suitable to an endocytic process. In addition, the obtained nanogels revealed high loading capacity of anticancer drug vs. dry gel (circa 16%) and they exhibited much better stability and enhanced drug release under the typical conditions existing in cancer cells. Size of obtained nanogels was investigated by dynamic light scattering (DLS). It appeared that nanoparticle size was in the range from ca. 40 to 200nm. In 0.01M solution of glutathione (GSH) the -S-S- bonds were reduced and the nanogel particles were degraded. This could be seen in obtained SEM and TEM micrographs. The cytotoxicity investigation against the HeLa cells showed that DOX loaded nanogels were more cytotoxic (IC50=0.51µM) than free DOX (IC50=0.83µM), while unloaded nanogels did not inhibit proliferation of the cells. It was also found that the nanogels loaded with DOX reached a high intracellular concentration in HeLa cells just after 2h while free DOX needed 6h for that.

l-Cystine Diamides as l-Cystine Crystallization Inhibitors for Cystinuria.

l-Cystine bismorpholide (1a) and l-cystine bis(N'-methylpiperazide) (1b) were seven and twenty-four times more effective than l-cystine dimethyl ester (CDME) in increasing the metastable supersaturation range of l-cystine, respectively, effectively inhibiting l-cystine crystallization. This behavior can be attributed to inhibition of crystal growth at microscopic length scale, as revealed by atomic force microscopy. Both 1a and 1b are more stable than CDME, and 1b was effective in vivo in a knockout mouse model of cystinuria.

Oral administration of the amino acids cystine and theanine attenuates the adverse events of S-1 adjuvant chemotherapy in gastrointestinal cancer patients.

BACKGROUND: Nutritional therapy is used to reduce the adverse events (AEs) of anticancer drugs. Here, we determined whether the amino acids cystine and theanine, which provide substrates for glutathione, attenuated the AEs of S-1 adjuvant chemotherapy. METHODS: Patients scheduled to receive S-1 adjuvant chemotherapy were randomized to the C/T or the control groups. The C/T group received 700 mg cystine and 280 mg theanine orally 1 week before the administration of S-1, which then continued for 5 weeks. Each group received S-1 for 4 weeks. Blood sampling was performed and AEs were evaluated (CTCAE ver. 4.0) before and after the administration of S-1. S-1 was discontinued when AEs ≥ grade 2 occurred. RESULTS: The incidences of AEs of any grade and those over grade 2 were lower in the C/T group than in the controls. The incidence of diarrhea (G ≥ 2) was significantly less (p < 0.05) in the C/T group (3.1 %) than in the controls (25.8 %). The duration and completion rate of the S-1 adjuvant chemotherapy were significantly longer (p < 0.01) and higher (p < 0.01), respectively, in the C/T group (complete ratio: 75.0 %, duration: 24.8 ± 5.8 days) than in the controls (complete ratio: 35.5 %, duration: 20.0 ± 7.7 days). CONCLUSIONS: The oral administration of cystine and theanine attenuated the AEs of S-1 adjuvant chemotherapy and increased the S-1 completion rate, suggesting that cystine and theanine is a useful supportive care for chemotherapy.

Effect of digestible methionine + cystine concentration on performance, egg quality and blood metabolites in laying hens.

The estimation of sulphur amino acid requirement is a vital key to providing appropriate nutrition in poultry. The estimation of amino acid requirement depends on what production parameter is taken into consideration for optimisation. A complete randomised block design was performed with 5 treatments and 6 replicates of 8 Hy-line layers (W-36) each from 32 to 44 weeks of age. The blocks were made to have a replicate of each treatment. The dietary treatments were consisted of 5 concentrations of digestible sulphur amino acid (DSAA) at 5.1, 5.6, 6.1, 6.6 and 7.1 (g/kg). Egg production, egg mass, egg weight and feed conversion ratio (FCR) were significantly affected by an increase in DSAA intake. However, feed intake, egg component yield, Haugh unit, specific gravity, eggshell thickness, egg protein and dry matter (DM) were not altered by DSAA intake. A significant increment in plasma high-density lipoprotein was concomitant with a reduction in low-density lipoprotein when DSAA intake was increased. However, triglyceride, cholesterol, uric acid and total protein in plasma were not affected by DSAA intake. The DSAA requirements estimated by the linear broken-line model to optimise egg production, egg mass, egg weight and FCR were 678, 673, 641 and 656 mg/bird.d in the whole experimental period, respectively. The DSAA requirement estimated by the quadratic broken-line model to optimise egg production, egg mass, egg weight and FCR were 4.71%, 7.87%, 8.73% and 7.62% higher than those estimated by linear broken-line fit model in the whole experimental period, respectively.

The extracellular redox state modulates mitochondrial function, gluconeogenesis, and glycogen synthesis in murine hepatocytes.

Circulating redox state changes, determined by the ratio of reduced/oxidized pairs of different metabolites, have been associated with metabolic diseases. However, the pathogenic contribution of these changes and whether they modulate normal tissue function is unclear. As alterations in hepatic gluconeogenesis and glycogen metabolism are hallmarks that characterize insulin resistance and type 2 diabetes, we tested whether imposed changes in the extracellular redox state could modulate these processes. Thus, primary hepatocytes were treated with different ratios of the following physiological extracellular redox couples: ß-hydroxybutyrate (ßOHB)/acetoacetate (Acoc), reduced glutathione (GSH)/oxidized glutathione (GSSG), and cysteine/cystine. Exposure to a more oxidized ratio via extracellular ßOHB/Acoc, GSH/GSSG, and cysteine/cystine in hepatocytes from fed mice increased intracellular hydrogen peroxide without causing oxidative damage. On the other hand, addition of more reduced ratios of extracellular ßOHB/Acoc led to increased NAD(P)H and maximal mitochondrial respiratory capacity in hepatocytes. Greater ßOHB/Acoc ratios were also associated with decreased ß-oxidation, as expected with enhanced lipogenesis. In hepatocytes from fasted mice, a more extracellular reduced state of ßOHB/Acoc led to increased alanine-stimulated gluconeogenesis and enhanced glycogen synthesis capacity from added glucose. Thus, we demonstrated for the first time that the extracellular redox state regulates the major metabolic functions of the liver and involves changes in intracellular NADH, hydrogen peroxide, and mitochondrial respiration. Because redox state in the blood can be communicated to all metabolically sensitive tissues, this work confirms the hypothesis that circulating redox state may be an important regulator of whole body metabolism and contribute to alterations associated with metabolic diseases.