Phase I clinical trial of KML001 monotherapy in patients with advanced solid tumors.

BACKGROUND: We evaluated the tolerability, pharmacokinetics (PK) and preliminary efficacy of KML001, an oral trivalent arsenical, as a monotherapy in patients with advanced solid tumors. RESEARCH DESIGN AND METHODS: With a standard 3 + 3 design for dose-escalation stage, the planned dose levels of KML001 were 5, 7.5, 10, 12.5, and 15 mg/day for 28 days. Once the maximum tolerated dose was determined, 22 subjects were additionally enrolled for dose-expansion stage. PK analysis was performed in the 5, 10, and 15 mg/day cohort at the dose-escalation stage and also at the dose-expansion stage. Moreover, response was assessed using the standard RECIST 1.1. RESULTS: A total of 45 Korean subjects were enrolled. No DLT was reported at the dose-escalation stage. Three DLTs, two cases of prolonged QTc interval and one of neutropenia, were reported in the 12.5 mg/day cohort at the dose-expansion stage. Higher total daily doses up to 12.5 mg/day of KML001 resulted in higher trough plasma concentrations. Among the 18 subjects who completed 2 cycles of therapy, 15 had progressive disease and 3 had stable disease. CONCLUSIONS: Doses equal to or greater than 10 mg/day KML001 alone were tolerable and produced plasma concentrations higher than biologically relevant targets.

Chlorogenic acid prevents hepatotoxicity in arsenic-treated mice: role of oxidative stress and apoptosis.

Arsenic is a potent and toxic heavy metal found in the environment that causes health problems, including liver disease, in humans and animals. Chlorogenic acid (CA) is the most abundant caffeoylquinic acid isomer present in plants. This study aims to assess how CA protects the liver tissue following sodium arsenite (NaAsO2)-induced toxicity in mice. Male Swiss mice were allocated into 5 groups: Control, intragastrically administered CA (200 mg/kg), intragastrically administered NaAsO2 (5 mg/kg), and two groups administered with CA (100 and 200 mg/kg) and NaAsO2. CA was administered 30 min before NaAsO2 and all the mice were treated daily for 28 days. To investigate the biochemical, histopathological, immunohistochemical, and molecular changes, blood and liver samples were collected. NaAsO2 treatment increased the liver function biomarkers such as alanine transaminase, aspartate transaminase, alkaline phosphatase, and total bilirubin. Lipid and nitric oxide production was elevated. Glutathione content and the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase decreased, indicating a disturbance in redox homeostasis. Histopathological examination revealed a granular degeneration of hepatocytes, infiltration of inflammatory cells, and centrilobular hepatocyte necrosis. Furthermore, tumor necrosis factor-α and interleukin-1ß were upregulated upon NaAsO2 treatment, suggesting the induction of inflammation. Moreover, NaAsO2 triggered apoptosis in the liver by upregulating Bax and caspase-3 and downregulating Bcl-2. However, CA abrogated the biochemical, molecular, and histological changes, reflecting its hepatoprotective role in response to NaAsO2 treatment. Our findings demonstrate that CA could be a potential therapeutic to minimize NaAsO2-induced hepatic injury.

Involvement of proinflammatory cytokines and metallothionein in the repairing of arsenic-mediated uterine tissue damage by curcumin.

Background Curcumin is extensively used as a therapeutic intervention for treating several ailments. The antioxidant curcumin has an anti-inflammatory and chelating property with arsenic to exhibit a strong therapeutic effect on reproductive organs. This study was undertaken to describe the protective effect of noninvasive administration of curcumin against sodium-arsenite-mediated uterine hazards in female Wistar rats. Methods Twenty-four female Wistar rats were randomly divided into four groups. The treatment was continued for 8 days and given orally sodium arsenite (10 mg/kg body weight) in combination with curcumin (20 mg/kg body weight). Results Our evaluation revealed that 8 days of sodium arsenite (10 mg/kg body weight) treatment reduced the activities of the uterine enzymatic antioxidants superoxide dismutase, catalase, and peroxidase. Blood levels of vitamin B12 and folic acid decreased followed by an increased serum lactate dehydrogenase, homocysteine level, and hepatic metallothionein-1 in arsenic-treated rats. Necrosis of uterine tissue along with the disruption of ovarian steroidogenesis was marked in arsenic-treated rats with an upregulation of uterine NF-κB and IL-6 along with a raised level of serum TNF-α. Oral administration of curcumin (20 mg/kg body weight/day) in arsenic-treated rats significantly reinstated these alterations of the antioxidant system followed by an improvement of ovarian steroidogenesis and the circulating level of B12 and folate along with the downregulation of serum homocysteine, metallothionein-1, and cytokines. Conclusions The findings of this study clearly and strongly elucidated that arsenic-induced oxidative stress in uterus is linked to an alteration of inflammation-signaling biomarkers and these have been protected through the co-administration of curcumin due to its anti-inflammatory, free radical scavenging, and antioxidant activity by the possible regulation of an S-adenosine methionine pool.

Endocrine Disruption Alters Developmental Energy Allocation and Performance in Rana temporaria.

Environmental change exposes wildlife to a wide array of environmental stressors that arise from both anthropogenic and natural sources. Many environmental stressors with the ability to alter endocrine function are known as endocrine disruptors, which may impair the hypothalamus-pituitary-thyroid axis resulting in physiological consequences to wildlife. In this study, we investigated how the alteration of thyroid hormone (TH) levels due to exposure to the environmentally relevant endocrine disruptor sodium perchlorate (SP; inhibitory) and exogenous L-thyroxin (T4; stimulatory) affects metabolic costs and energy allocation during and after metamorphosis in a common amphibian (Rana temporaria). We further tested for possible carry-over effects of endocrine disruption during larval stage on juvenile performance. Energy allocated to development was negatively related to metabolic rate and thus, tadpoles exposed to T4 could allocate 24% less energy to development during metamorphic climax than control animals. Therefore, the energy available for metamorphosis was reduced in tadpoles with increased TH level by exposure to T4. We suggest that differences in metabolic rate caused by altered TH levels during metamorphic climax and energy allocation to maintenance costs might have contributed to a reduced energetic efficiency in tadpoles with high TH levels. Differences in size and energetics persisted beyond the metamorphic boundary and impacted on juvenile performance. Performance differences are mainly related to strong size-effects, as altered TH levels by exposure to T4 and SP significantly affected growth and developmental rate. Nevertheless, we assume that juvenile performance is influenced by a size-independent effect of achieved TH. Energetic efficiency varied between treatments due to differences in size allocation of internal macronutrient stores. Altered TH levels as caused by several environmental stressors lead to persisting effects on metamorphic traits and energetics and, thus, caused carry-over effects on performance of froglets. We demonstrate the mechanisms through which alterations in abiotic and biotic environmental factors can alter phenotypes at metamorphosis and reduce lifetime fitness in these and likely other amphibians.

KML001, an arsenic compound, as salvage chemotherapy in refractory biliary tract cancers: A prospective study.

BACKGROUND: Sodium meta-arsenite (NaAsO2, KML001) is a potential oral anticancer agent acting on telomerase and telomere length. This prospective study evaluated its safety, tolerability, and effectiveness as salvage chemotherapy in patients with advanced biliary tract cancer (BTC) resistant to gemcitabine-based chemotherapy. METHODS: Forty-four patients (21 women and 23 men) with advanced BTC and failure history of gemcitabine-based chemotherapy, performance status (PS) 0-2, normal cardiac, hepatic, and renal function were enrolled. Daily dose of KML001 (7.5 mg. p.o.) was administered to eligible subjects for 24 weeks divided into six treatment cycles. Response was evaluated bimonthly using CT. RESULTS: After an average of 1.5 months of treatment (range: 0.5-10.0), 3 patients (6.8%) obtained progression-free status, 23 patients (52.3%) had disease progression, and 18 patients (40.9%) dropped out before evaluation. One patient (2.3%) completed six treatment cycles without progression. During the treatment, morphine dosage kept the same or decreased in 20 patients (47.6%). Nine patients (20.5%) experienced grade-3 adverse events (AEs), while no patient experienced grade-4 AEs. The most common AEs were liver enzyme elevation (11/44, 25%) and anemia (10/44, 22.7%). KML001 was discontinued in six patients (13.6%) due to AEs, including liver toxicity (n = 3), QTc prolongation (n = 2), and abdominal pain (n = 1). CONCLUSIONS: KML001 did not have enough anticancer effect on patients with advanced BTC resistant to gemcitabine. However, KML001 was safe and well-tolerable in terms of AEs and pain control when used as salvage therapy. Further studies are needed to establish arsenic agents as a reliable treatment option in patients with BTC.

Antioxidant supplementation upregulates calbindin expression in cerebellar Purkinje cells of rat pups subjected to post natal exposure to sodium arsenite.

Optimal cytoplasmic calcium (Ca2+) levels have been associated with adequate cell functioning and neuronal survival. Altered intracellular Ca2+ levels following impaired Ca2+ homeostasis could induce neuronal degeneration or even cell death. There are reports of arsenite induced oxidative stress and the associated disturbances in intracellular calcium homeostasis. The present study focused on determining the strategies that would modulate tissue redox status and calcium binding protein (CaBP) (Calbindin D28k-CB) expression affected adversely by sodium arsenite (NaAsO2) exposure (postnatal) of rat pups. NaAsO2 alone or along with antioxidants (AOXs) (alpha lipoic acid or curcumin) was administered by intraperitoneal (i.p.) route from postnatal day (PND) 1-21 (covering rapid brain growth period - RBGP) to experimental groups and animals receiving sterile water by the same route served as the controls. At the end of the experimental period, the animals were subjected to euthanasia and the cerebellar tissue obtained therefrom was processed for immunohistochemical localization and western blot analysis of CB protein. CB was diffusely expressed in cell body as well as dendritic processes of Purkinje cells (PCs) along the PC Layer (PCL) in all cerebellar folia of the control and the experimental animals. The multilayered pattern of CB +ve cells along with their downregulated expression and low packing density was significantly evident in the arsenic (iAs) alone exposed group as against the controls and AOX supplemented groups. The observations are suggestive of AOX induced restoration of CaBP expression in rat cerebellum following early postnatal exposure to NaAsO2.

Bromide supplementation exacerbated the renal dysfunction, injury and fibrosis in a mouse model of Alport syndrome.

A seminal study recently demonstrated that bromide (Br-) has a critical function in the assembly of type IV collagen in basement membrane (BM), and suggested that Br- supplementation has therapeutic potential for BM diseases. Because salts of bromide (KBr and NaBr) have been used as antiepileptic drugs for several decades, repositioning of Br- for BM diseases is probable. However, the effects of Br- on glomerular basement membrane (GBM) disease such as Alport syndrome (AS) and its impact on the kidney are still unknown. In this study, we administered daily for 16 weeks 75 mg/kg or 250 mg/kg (within clinical dosage) NaBr or NaCl (control) via drinking water to 6-week-old AS mice (mouse model of X-linked AS). Treatment with 75 mg/kg NaBr had no effect on AS progression. Surprisingly, compared with 250 mg/kg NaCl, 250 mg/kg NaBr exacerbated the progressive proteinuria and increased the serum creatinine and blood urea nitrogen in AS mice. Histological analysis revealed that glomerular injury, renal inflammation and fibrosis were exacerbated in mice treated with 250 mg/kg NaBr compared with NaCl. The expressions of renal injury markers (Lcn2, Lysozyme), matrix metalloproteinase (Mmp-12), pro-inflammatory cytokines (Il-6, Il-8, Tnf-α, Il-1ß) and pro-fibrotic genes (Tgf-ß, Col1a1, α-Sma) were also exacerbated by 250 mg/kg NaBr treatment. Notably, the exacerbating effects of Br- were not observed in wild-type mice. These findings suggest that Br- supplementation needs to be carefully evaluated for real positive health benefits and for the absence of adverse side effects especially in GBM diseases such as AS.

Absence seizure associated with coloprep consumption in colonoscopy / Convulsão de ausência com o uso de Coloprep em colonoscopia

Coloprep is a bowel preparatory solution given before endoscopic procedures to get a unobscured internal vision. It has among its constituent's sodium sulphate, potassium sulphate and magnesium sulphate which produce an osmotic effect in the bowel. However, the use of such agents in hyponatremic and patients predisposed to seizures can have adverse ramifications. The current case outlines manifestation of absence seizure in a 52-year-old male patient who was administered Coloprep for colonoscopy. There was absence of other predisposing factors and the symptoms were ameliorated using timely identification and rectification of the underlying derangements.

Coloprep é uma solução preparatória intestinal administrada antes de procedimentos endoscópicos, com o objetivo de se ter uma visão interna não obscurecida. Entre os constituintes de Coloprep, observa-se sulfato de sódio, sulfato de potássio e sulfato de magnésio, que provocam efeito osmótico no intestino. Mas o uso de tais agentes em pacientes hiponatrêmicos e com predisposição para convulsões pode ter ramificações adversas. O caso em tela delineia uma manifestação de convulsão de ausência em paciente do gênero masculino com 52 anos e que recebeu Coloprep para colonoscopia. Não havia outros fatores predisponentes e os sintomas melhoraram graças à oportuna identificação e correção dos transtornos subjacentes.

Optimization of alginate purification using polyvinylidene difluoride membrane filtration: Effects on immunogenicity and biocompatibility of three-dimensional alginate scaffolds.

Sodium alginate is an effective biomaterial for tissue engineering applications. Non-purified alginate is contaminated with protein, lipopolysaccharide, DNA, and RNA, which could elicit adverse immunological reactions. We developed a purification protocol to generate biocompatible alginate based on (a) activated charcoal treatment, (b) use of hydrophobic membrane filtration (we used hydrophobic polyvinylidene difluoride membranes to remove organic contaminants), (c) dialysis, and finally (d) ethanol precipitation. Using this approach, we could omit pre-treatment with chloroform and significantly reduce the quantities of reagents used. Purification resulted in reduction of residual protein by 70% down to 0.315 mg/g, DNA by 62% down to 1.28 µg/g, and RNA by 61% down to less than 10 µg/g, respectively. Lipopolysaccharide levels were reduced by >90% to less than 125 EU/g. Purified alginate did not induce splenocyte proliferation in vitro. Three-dimensional scaffolds generated from purified alginate did not elicit a significant foreign body reaction, fibrotic overgrowth, or macrophage infiltration 4 weeks after implantation. This study describes a simplified and economical alginate purification method that results in alginate purity, which meets clinically useful criteria.

[Study on congenital cardiac anomalies induced by arsenic exposure before and during maternal pregnancy in fetal rats].

OBJECTIVE: To investigate the effects of arsenic exposure before and during maternal pregnancy on heart development of fetal rats. METHODS: According to body weight, thirty-two female SD rats (30 to 40 days of age) were randomly divided into control group, low dose group, middle dose group and high dose group with 8 rats per group. They were allowed free access to drinking water with 0, 37.5, 75 and 150 mg/L of sodium arsenite (NaAsO2) for 6 weeks, respectively. Then all the female rats and adult male SD rats were caged together for mating. Once female rats were determined to be pregnant, they would continue to drink deionized distilled water containing different concentrations of sodium arsenite for another 2 weeks. On embryonic day 16, rats were sacrificed to harvest fetuses. Female rats' weight changes, abortions, absorbed fetus number, growth and development of fetal rats were observed. Hematoxylin-eosin staining of serial cardiac slices was performed in embryos to observe cardiac morphology and structure. Fur arsenic contents of female rats were determined with the method of atomic fluorescence spectrometry. RESULTS: Subchronic arsenic exposure caused slow weight growth in female rats. There were two cases of abortion in middle dose group and high dose group, respectively. Compared with these of control group, fetal and placental weight decreased (P < 0.05), and the incidence of fetal absorption increased (P < 0.05) in all arsenic-treated groups. Cardiac malformations in fetal rats including ventricular septal defect, atrial septal defect and tetralogy of Fallot were observed in low, middle and high dose group. The incidence of cardiac malformations increased with the increase of arsenic concentrations in drinking water. Compared with that of control group, the incidence of cardiac malformations remarkably increased in both middle and high dose groups (P < 0.05). Fur arsenic contents increased with the increase of arsenic concentrations in drinking water (P < 0.01). CONCLUSION: Arsenic exposure before and during maternal pregnancy could cause abnormal cardiac development in fetal rats, and increased the risk of congenital heart disease.

Antioxidant Potential of Spirulina platensis Mitigates Oxidative Stress and Reprotoxicity Induced by Sodium Arsenite in Male Rats.

The present study aimed to examine the protective role of Spirulina platensis (S. platensis) against arsenic-induced testicular oxidative damage in rats. Arsenic (in the form of NaAsO2 at a dose of 6.3 mg/kg body weight for 8 weeks) caused a significant accumulation of arsenic in testicular tissues as well as a decrease in the levels of testicular superoxide dismutase (SOD), catalase (CAT), reduced glutathione, and zinc. Moreover, it significantly decreased plasma testosterone, luteinizing hormone (LH), triiodothyronine (T3), and thyroxine (T4) levels and reduced sperm motility and sperm count. Arsenic (AS) led to a significant increase in testicular malondialdehyde (MDA), tumour necrosis factor alpha (TNF-α), nitric oxide (NO), and sperm abnormalities. S. platensis at a dose of 300 mg/kg was found to attenuate As-induced oxidative stress, testicular damage, and sperm abnormalities by its potent antioxidant activity. S. platensis may represent a potential therapeutic option to protect the testicular tissue from arsenic intoxication.

Effect of sodium arsenite on reproductive organs of female Wistar rats.

The present study was performed to investigate the subchronic effect of sodium arsenite on female Wistar rats. Mature female rats were divided into 4 groups of 12 animals each. Group I received distilled water, whereas the other 3 groups received sodium arsenite at 10, 30, and 50 µg/L doses for 60 days through drinking water. Half of the animals from each group were dissected after 30 days and the remaining after 60 days. A disruption in estrous cycle was observed with prolonged diestrous and metestrous phases. A significant increase in ovarian surface epithelium and follicular atresia was observed in treated rats (p ≤ .05). A significant decrease (p ≤ .05) in the uterine myometrium was observed. A significant increase (p ≤ .05) in the levels of lipid peroxidation along with decrease in the activities of antioxidant enzymes was observed. The results revealed that subchronic exposure of sodium arsenite causes degenerative changes in reproductive organs and induces oxidative stress in female rats.

Arsenic compromises conducting airway epithelial barrier properties in primary mouse and immortalized human cell cultures.

Arsenic is a lung toxicant that can lead to respiratory illness through inhalation and ingestion, although the most common exposure is through contaminated drinking water. Lung effects reported from arsenic exposure include lung cancer and obstructive lung disease, as well as reductions in lung function and immune response. As part of their role in innate immune function, airway epithelial cells provide a barrier that protects underlying tissue from inhaled particulates, pathogens, and toxicants frequently found in inspired air. We evaluated the effects of a five-day exposure to environmentally relevant levels of arsenic {<4µM [~300 µg/L (ppb)] as NaAsO2} on airway epithelial barrier function and structure. In a primary mouse tracheal epithelial (MTE) cell model we found that both micromolar (3.9 µM) and submicromolar (0.8 µM) arsenic concentrations reduced transepithelial resistance, a measure of barrier function. Immunofluorescent staining of arsenic-treated MTE cells showed altered patterns of localization of the transmembrane tight junction proteins claudin (Cl) Cl-1, Cl-4, Cl-7 and occludin at cell-cell contacts when compared with untreated controls. To better quantify arsenic-induced changes in tight junction transmembrane proteins we conducted arsenic exposure experiments with an immortalized human bronchial epithelial cell line (16HBE14o-). We found that arsenic exposure significantly increased the protein expression of Cl-4 and occludin as well as the mRNA levels of Cl-4 and Cl-7 in these cells. Additionally, arsenic exposure resulted in altered phosphorylation of occludin. In summary, exposure to environmentally relevant levels of arsenic can alter both the function and structure of airway epithelial barrier constituents. These changes likely contribute to the observed arsenic-induced loss in basic innate immune defense and increased infection in the airway.

CD44v6 expression in human skin keratinocytes as a possible mechanism for carcinogenesis associated with chronic arsenic exposure.

Inorganic arsenic is a well-known human skin carcinogen. Chronic arsenic exposure results in various types of human skin lesions, including squamous cell carcinoma (SCC). To investigate whether mutant stem cells participate in arsenic-associated carcinogenesis, we repeatedly exposed the HaCaT cells line to an environmentally relevant level of arsenic (0.05 ppm) in vitro for 18 weeks. Following sodium arsenic arsenite administration, cell cycle, colony-forming efficiency (CFE), cell tumorigenicity, and expression of CD44v6, NF-κB and p53, were analyzed at different time points (0, 5, 10, 15, 20, 25 and 30 passages). We found that a chronic exposure of HaCaT cells to a low level of arsenic induced a cancer stem- like phenotype. Furthermore, arsenic-treated HaCaT cells also became tumorigenic in nude mice, their growth cycle was predominantly in G2/M and S phases. Relative to nontreated cells, they exhibited a higher growth rate and a significant increase in CFE. Western blot analysis found that arsenic was capable of increasing cell proliferation and sprouting of cancer stem-like phenotype. Additionally, immunohistochemical analysis demonstrated that CD44v6 expression was up-regulated in HaCaT cells exposed to a low level of arsenic during early stages of induction. The expression of CD44v6 in arsenic-treated cells was positively correlated with their cloning efficiency in soft agar (r=0.949, P=0.01). Likewise, the expressions of activating transcription factor NF-κB and p53 genes in the arsenic-treated HaCaT cells were significantly higher than that in non-treated cells. Higher expressions of CD44v6, NF-κB and p53 were also observed in tumor tissues isolated from Balb/c nude mice. The present results suggest that CD44v6 may be a biomarker of arsenic-induced neoplastic transformation in human skin cells, and that arsenic promotes malignant transformation in human skin lesions through a NF-κB signaling pathway-stimulated expression of CD44v6.

Comparative effects of in ovo exposure to sodium perchlorate on development, growth, metabolism, and thyroid function in the common snapping turtle (Chelydra serpentina) and red-eared slider (Trachemys scripta elegans).

Perchlorate is a surface and groundwater contaminant found in areas associated with munitions and rocket manufacturing and use. It is a thyroid-inhibiting compound, preventing uptake of iodide by the thyroid gland, ultimately reducing thyroid hormone production. As thyroid hormones influence metabolism, growth, and development, perchlorate exposure during the embryonic period may impact embryonic traits that ultimately influence hatchling performance. We topically exposed eggs of red-eared sliders (Trachemys scripta) and snapping turtles (Chelydra serpentina) to 200 and 177 µg/g of perchlorate (as NaClO(4)), respectively, to determine impacts on glandular thyroxine concentrations, embryonic growth and development, and metabolic rates of hatchlings for a period of 2 months post-hatching. In red-eared sliders, in ovo perchlorate exposure delayed hatching, increased external yolk size at hatching, increased hatchling mortality, and reduced total glandular thyroxine concentrations in hatchlings. In snapping turtles, hatching success and standard metabolic rates were reduced, liver and thyroid sizes were increased, and total glandular thyroxine concentrations in hatchlings were reduced after exposure to perchlorate. While both species were negatively affected by exposure, impacts on red-eared sliders were most severe, suggesting that the slider may be a more sensitive sentinel species for studying effects of perchlorate exposure to turtles.

Analysis of neuroglobin mRNA expression in rat brain due to arsenite-induced oxidative stress.

Arsenic (As) in drinking water is a toxicant causing several health problems including nervous system disturbance. Neuroglobin (Ngb) is a tissue globin in nervous system playing protective role against oxidative stress in many injuries. This study was to investigate how long arsenite exposure (sodium arsenite 7.5 mg/kg/day) could induce oxidative stress in blood and brain of rats and to determine whether Ngb expression in rat brain changed due to oxidative stress. Results showed that superoxide dismutase (SOD) activity and malondialdehyde (MDA) level in serum and brain homogenates and reactive oxygen species (ROS) generation in red blood cells (RBCs) did not change in the rats exposed to arsenite for 8 weeks. In the rats exposed to arsenite for 16 weeks, SOD activity decreased (serum: P < 0.05; brain homogenates: P < 0.01) and MDA level increased (P < 0.01) in serum and brain homogenates; ROS production increased (P < 0.01) in RBC. When oxidative stress occurred, Ngb mRNA expression did not change in whole brain, cerebral cortex, midbrain, and hippocampus; however, Ngb mRNA expression increased significantly (P < 0.05) in cerebellum compared to the control group. This study suggests that arsenite exposure for 16 weeks can lead to oxidative stress of blood and brain of rats. Ngb may play a protective role in cerebellum when oxidative stress occurs due to arsenite exposure.

Inorganic arsenic impairs proliferation and cytokine expression in human primary T lymphocytes.

Inorganic arsenic is a toxic environmental contaminant to which humans are mainly exposed through drinking water. This metalloid impairs functions of several key immune cells. Particularly, it reduces IL-2 secretion and proliferation of blood peripheral mononuclear cells stimulated by lectins that, however, do not mimic physiological T cell activation. The present study used isolated human T cells activated, in a more physiological manner, through stimulation with CD3/CD28 antibodies, to carefully analyze the impact of arsenic on T cell proliferation and cytokine expression. We demonstrate that non cytotoxic concentrations of sodium arsenite (As(III), 0.25-2µM) significantly reduce T cell proliferation by increasing the percentage of non dividing cells blocked in G1 phase and by preventing cyclin D3 and CDC25A expression. They also markedly, although not totally, reduces IL-2 expression at both mRNA and protein levels; however, metalloid-dependent inhibition of T cells could not be reversed by addition of recombinant IL-2. In addition, As(III) markedly reduces secretion of interferon-γ without impairing that of IL-4 and IL-13; it also decreases interferon-γ mRNA levels but increases those of IL-13. Finally, simultaneously to its immune effects, As(III) rapidly and potently increases expression of the redox-sensitive genes HMOX1, NQO1 and GCLM in activated T cells without altering the levels of reactive oxygen species. In conclusion, our results demonstrate that As(III) inhibits T cell proliferation, independently of IL-2, and alters the Th balance of cytokines secreted by co-stimulated T cells which thus constitute direct targets of this major environmental contaminant.

[6]-Gingerol isolated from ginger attenuates sodium arsenite induced oxidative stress and plays a corrective role in improving insulin signaling in mice.

Arsenic toxicity induces type 2 diabetes via stress mediated pathway. In this study, we attempt to reveal how sodium arsenite (iAs) could induce stress mediated impaired insulin signaling in mice and if an isolated active fraction of ginger, [6]-gingerol could attenuate the iAs intoxicated hyperglycemic condition of mice and bring about improvement in their impaired insulin signaling. [6]-Gingerol treatment reduced elevated blood glucose level and oxidative stress by enhancing activity of super oxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and GSH. [6]-Gingerol also helped in increasing plasma insulin level, brought down after iAs exposure. iAs treatment to primary cell culture of ß-cells and hepatocytes in vitro produced cyto-degenerative effect and accumulated reactive oxygen species (ROS) in pancreatic ß-cells and hepatocytes of mice. [6]-Gingerol appeared to inhibit/intervene iAs induced cyto-degeneration of pancreatic ß-cells and hepatocytes, helped in scavenging the free radicals. The over-expression of TNFα and IL6 in iAs intoxicated mice was down-regulated by [6]-gingerol treatment. iAs intoxication reduced expression levels of GLUT4, IRS-1, IRS-2, PI3K, AKT, PPARγ signaling molecules; [6]-gingerol mediated its action through enhancing the expressions of these signaling molecules, both at protein and mRNA levels. Thus, our results suggest that [6]-gingerol possesses an anti-hyperglycemic property and can improve impaired insulin signaling in arsenic intoxicated mice.