Response of the antioxidant enzymes of rats following oral administration of metal-oxide nanoparticles (Al2O3, CuO, TiO2)

Metal-oxide nanoparticles (NPs), as a new emerging technological compound, promise a wide range of usage areas and consequently have the potential to cause environmental toxicology. In the present work, aluminum (Al₂O₃), copper (CuO), and titanium (TiO₂) nanoparticles (NPs) were administered via oral gavage to mature female rats (Rattus norvegicus var. albinos) for 14 days with a dose series of 0 (control), 0.5, 5, and 50 (mg/kg b.w./day). Enzyme activities of the antioxidant system such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), and glutathione reductase (GR) in the liver were measured. Transmission electron microscope (TEM) images of the liver were taken to demonstrate NP accumulation and distribution in liver tissue. Data showed that all NPs caused some significant (P > 0.05) alterations in the activities of antioxidant enzymes. CAT activity increased after CuO and TiO₂ administrations, while SOD activity decreased after Al₂O₃ administration. The activities of enzymes associated with glutathione (GR, GPx, GST) metabolisms were also significantly altered by NPs. GPx activity increased in rats received Al₂O₃, CuO NPs, while GR activity increased only by Al₂O₃. However, there were increases (TiO₂) and decreases (CuO) in GST activity in the liver of rats. TEM images of the liver demonstrated that all NPs accumulated in the liver, even at the lowest dose. This study indicated that the antioxidant enzymes in the liver of rats were affected by all NPs, suggesting the antioxidant system of rats suffered after NP administration.

Moringa oleifera Leaves Extract Protects Titanium Dioxide Nanoparticles-Induced Nephrotoxicity via Nrf2/HO-1 Signaling and Amelioration of Oxidative Stress

The efficacy of Moringa oleifera leaf extract (MO) in alleviating nephrotoxicity induced by titanium dioxide nanoparticles (TiO₂ NPs) was studied. Rats were divided into four groups. Group I received distilled water. Group II received TiO₂NPs. Group III received both TiO₂NPs suspension beside MO. Group IV received MO only. Kidney KIM-1, NF-кB TNF-α, and HSP-70 expression were significantly upregulated while both Nrf2 and HO-1were significantly downregulated in TiO₂NPs-treated rats. MO decreases expression of KIM-1, NF-кB, TNF-α, and HSP-70. In addition, MO has markedly upregulated the expression of Nrf2 and HO-1. In conclusion, MO can inhibit nephrotoxicity by suppressing oxidative stress and inflammation. These effects are suggested to be mediated by activating Nrf2/HO-1.The biochemical analysis and histopathological finding reinforced these results. These data support the antioxidant properties' nutraceutical role of MO against TiO₂NPs-induced toxicity.

Titanium Dioxide Nanoparticle/Gelatin: A Potential Burn Wound Healing Biomaterial

INTRODUCTION

Over the past few decades, the application of nanotechnology has gained progressive interest for the regeneration of injured and burned tissues.

OBJECTIVE

This study evaluates the effects of titanium dioxide (TiO₂) nanoparticle (NP)/gelatin on burn wound healing in mice.

MATERIALS AND METHODS

Sixty healthy male BALB/c mice with a full-thickness burn wound were randomized into 4 experimental groups of 15 animals each: (1) control group was treated with normal saline; (2) gelatin group was treated with gelatin-based ointment; (3) silver sulfadiazine group was treated with silver sulfadiazine 1% ointment; and (4) TiO₂ NP/gelatin group (TNG) received TiO₂ NP/gelatin. Wound size was measured on postoperative days 2, 6, 10, 14, 18, and 21, and histopathological studies of tissue samples were performed on postop days 7, 14, and 21.

RESULTS

The wound area reduction indicated that there was a significant difference between the TNG and other groups (P < .05). Quantitative histological and morphometric studies and the mean rank gained from the qualitative studies demonstrated that there was a significant difference between the TNG and other groups (P < .05).

CONCLUSIONS

In this study, TNG offered potential advantages in burn wound healing acceleration and improvement through angiogenesis stimulation, fibroblast proliferation, and granulation tissue formation in the early phases of healing. In addition, factors such as accelerated wound repair associated with earlier wound contraction and stability of the damaged area by rearrangement of granulation tissue and collagen fibers were also advantages of TNG.

Hybrid Alginate@TiO2 Porous Microcapsules as a Reservoir of Animal Cells for Cell Therapy

The number of patients suffering from diseases linked with hormone deficiency (e.g., type 1 diabetes mellitus) has significantly increased in recent years. As organ transplantation presents its limits, the design of novel robust devices for cell encapsulation is of great interest. The current study reports the design of a novel hybrid alginate microcapsule reinforced by titania via a biocompatible synthesis from an aqueous stable titania precursor (TiBALDH) and a cationic polyamine (PDDAC) under mild conditions. The biocompatibility of this one-pot synthesis was confirmed by evaluation of the cytotoxicity of the precursor, additive, product, and by-product. The morphology, structure, and properties of the obtained hybrid microcapsule were characterized in detail. The microcapsule displayed mesoporous, which was a key parameter to allow the diffusion of nutrients and metabolites and to avoid the entry of immune defenders. The hybrid microcapsule also showed enhanced mechanical stability compared to the pure alginate microcapsule, making it an ideal candidate as a cell reservoir. HepG2 model cells encapsulated in the hybrid microcapsules remained intact for 43 days as highlighted by fluorescent viability probes, their oxygen consumption, and their albumin secretion. The study provides a significant progress in the conception of the robust and biocompatible reservoirs of animal cells for cell therapy.

Effect of Silver Nanoparticles, Zinc Oxide Nanoparticles and Titanium Dioxide Nanoparticles on Microshear Bond Strength to Enamel and Dentin

AIM

This study was aimed to evaluate whether antibacterial pretreatment of enamel and dentin with silver nanoparticles (SNPs), zinc oxide nanoparticles (ZNPs) and titanium dioxide nanoparticles (TNPs) has any effect on the microshear bond strength of an etch-and-rinse adhesive system.

MATERIALS AND METHODS

Eighty human third molars were randomly assigned to eight subgroups (n = 10). Enamel groups included no pretreatment (E), pretreatments with SNPs (ESNP), ZNPs (EZNP) and TNPs (ETNP) before acid etching and adhesive application. Dentinal groups included no pretreat-ment (D), pretreatments with SNPs (DSNP), ZNPs (DZNP) and TNPs (DTNP). The specimens were bonded by Adper Single Bond and polyvinyl chloride microtubes and were restored with Z250 composite. The bonded surfaces underwent microshear bond strength (uSBS) test. Data in megapascal (MPa) were analyzed with the Kruskal-Wallis test and the Mann-Whitney test (p = 0.05).

RESULTS

There was not a significant difference among the groups in enamel (p > 0.05). There was no significant difference between the application of three nanoparticles and the control group in dentin. However, DSNPs had a higher uSBS (25.60 ± 14.61) than that of the DZNPs and DTNPs groups (p = 0.03 and p = 0.001, respectively). Also, the mean uSBS value was lower in dentin groups compared to the respective enamel groups (p < 0.05) except for groups DSNPs and ESNPs in which no significant difference was found (p > 0.05).

CONCLUSION

Pretreatment with SNPs, TNPs, and ZNPs can be suggested to achieve potent antibacterial activities without compromising the bond strength. The best result was obtained for pretreatment with SNPs compared to pretreatment with TNPs or ZNPs in dentin and enamel, albeit the differences were not significant in the enamel groups.

CLINICAL SIGNIFICANCE

Effective antibacterial treatment prior to adhesive bonding application is desirable to provide successful restoration if it would not adversely affect the bond strength of the adhesive system. Nanoparticles can be applied to meet this goal.

TiO2 nanoparticles cause mitochondrial dysfunction, activate inflammatory responses, and attenuate phagocytosis in macrophages: A proteomic and metabolomic insight

Titanium dioxide nanoparticles (TiO2 NPs) are widely used in food and cosmetics but the health impact of human exposure remains poorly defined. Emerging evidence suggests that TiO2 NPs may elicit immune responses by acting on macrophages. Our proteomic study showed that treatment of macrophages with TiO2 NPs led to significant re-organization of cell membrane and activation of inflammation. These observations were further corroborated with transmission electron microscopy (TEM) experiments, which demonstrated that TiO2 NPs were trapped inside of multi-vesicular bodies (MVB) through endocytotic pathways. TiO2 NP caused significant mitochondrial dysfunction by increasing levels of mitochondrial reactive oxygen species (ROS), decreasing ATP generation, and decreasing metabolic flux in tricarboxylic acid (TCA) cycle from 13C-labelled glutamine using GC-MS-based metabolic flux analysis. Further lipidomic analysis showed that TiO2 NPs significantly decreased levels of cardiolipins, an important class of mitochondrial phospholipids for maintaining proper function of electron transport chains. Furthermore, TiO2 NP exposure activates inflammatory responses by increasing mRNA levels of TNF-α, iNOS, and COX-2. Consistently, our targeted metabolomic analysis showed significantly increased production of COX-2 metabolites including PGD2, PGE2, and 15d-PGJ2. In addition, TiO2 NP also caused significant attenuation of phagocytotic function of macrophages. In summary, our studies utilizing multiple powerful omic techniques suggest that human exposure of TiO2 NPs may have profound impact on macrophage function through activating inflammatory responses and causing mitochondrial dysfunction without physical presence in mitochondria.

Enhancement of the Immune Function by Titanium Dioxide Nanorods and Their Application in Cancer Immunotherapy

With the rapid development of nanotherapy, concerns surrounding the possible use of nanomaterials-mediated immunomodulation are growing. Thus, evaluating the effects of novel materials for potential application in nanotherapy is essential. Herein, we studied the effects of TiO2-nanorods (NRs) on the immune function and their potential application in immunotherapy. TiO2-NRs exerted specific immunomodulatory effects on the main immune cells. Cytokines TNF-α and IL-2, which play a key role in antitumor processes, were upregulated more significantly than other cytokines (IL-4, IL-5, IFN-γ) in the main immune cells. The cells group treated with a high dose of TiO2-NRs (50 mg/L) for 12 h produced a higher TNF-α content of 530.4 pg/mL relative to that (238.2 pg/mL) treated with saline solution only. The TNF-α content increased to 2.2- and 4.9-fold for macrophages and lymphocytes, respectively. Also, we conclude that TiO2-NRs exposure may trigger T cell proliferation and bias toward Th1 immune response and cause a long-lasting activation of lymphocytes involved in adaptive immunity rather than an innate immunity in BALB/c mice. Furthermore, we explored the potential application of TiO2-NRs in immunotherapy. At a given dose of 1 mg/kg, the inhibition rate by TiO2-NRs (26.7%) was much higher than that by DOX (13.3%).

Co-exposure to titanium dioxide nanoparticles does not affect cadmium toxicity in radish seeds (Raphanus sativus)

Recent developments on environmental fate models indicate that as nano waste, engineered nanomaterials (ENMs) could reach terrestrial ecosystems thus potentially affecting environmental and human health. Plants can be therefore exposed to ENMs but controversial data in terms of fate and toxicity are currently available. Furthermore, there is a current lack of information on complex interactions/transformations to which ENMs undergo in the natural environment as for instance interacting with existing toxic compounds. The aim of the present study was to assess the behavior and biological effects of titanium dioxide nanoparticles (n-TiO₂) (Aeroxide P25, Degussa Evonik) and its interaction with cadmium (CdCl₂) in plants using radish seeds (Raphanus sativus L. Parvus) as model species. Radish seeds were exposed to n-TiO₂ (1-1000mg/L) and CdCl₂ (1-250mg/L) alone and in combination using a seed germination and seedling growth toxicity test OECD 208. Percentage of seed germination, germination index (GI) and root elongation were calculated. Cell morphology and oxidative stress parameters as glutathione-S-transferase (GST) and catalase activities (CAT) were measured in radish seeds after 5 days of exposure. Z-Average, PdI and Z-potential of n-TiO₂ in Milli-Q water as exposure medium were also determined. DLS analysis showed small aggregates of n-TiO₂, negative Z-potential and stable PdI in seed's exposure media. Germination percentage, GI and root length resulted affected by n-TiO₂ exposure compared to controls. In particular, n-TiO₂ at 1mg/L and 100mg/L did not affect radish seeds germination (100%) while at concentration of 10mg/L, 200mg/L, 500mg/L, and 1000mg/L a slight but not significant decrease of germination % was observed. Similarly root length and GI resulted significantly higher in seeds exposed to 10mg/L and 200mg/L compared to 1mg/L, 100mg/L, 500mg/L, 1000mg/L and control (p < 0.05). On the opposite, CdCl₂ significantly abolished germination % and GI compared to control seeds and a concentration dependent decrease on root elongation was observed against controls (p < 0.05). As well, significant decrease of germination %, GI and root elongation was observed in seeds co-exposed to n-TiO₂ and CdCl₂ at the highest concentrations (1000mg/L n-TiO₂ and 250mg/L CdCl₂) compared to co-exposed seeds at low concentration (1mg/L n-TiO₂ and 1mg/L CdCl₂) and controls (p < 0.05). Root elongation significantly increase compared to control at the lowest co-exposure concentration (p < 0.05). Similarly at intermediate concentrations of 10 and 100mg/L in co-exposure conditions, n-TiO₂ did not affect CdCl₂ toxicity. Concerning antioxidant enzymes, a significant increase of CAT activity in seeds exposed to single high n-TiO₂ concentration (1000mg/L) was observed while n-TiO₂ (1mg/L), CdCl₂ (1 and 250mg/L) and co-exposure resulted significantly decreased compared to controls (p < 0.05). Regarding GST activity, a slight increase in seeds exposed to 1000mg/L n-TiO₂ but no significantly was observed, however both n-TiO₂ and CdCl₂ alone (1 and 250mg/L, respectively) or in combinations caused a significant decrease in GST activity (p < 0.05). Therefore, overall data support the hypothesis that the presence of n-TiO₂ do not affect the toxicity of CdCl₂ at least at the highest concentration (100 and 250mg/L) in radish seeds. Morphological alterations in nuclei, vacuoles and shape of radish root cells were observed upon single Cd exposure and not abolished in the presence of n-TiO₂. Nevertheless, although n-TiO₂ seems not to reduce Cd toxicity at high concentration (up to 250mg/L), interactions cannot be excluded based on obtained results.

Reactive oxygen species damage drives cardiac and mitochondrial dysfunction following acute nano-titanium dioxide inhalation exposure

Nanotechnology offers innovation in products from cosmetics to drug delivery, leading to increased engineered nanomaterial (ENM) exposure. Unfortunately, health impacts of ENM are not fully realized. Titanium dioxide (TiO2) is among the most widely produced ENM due to its use in numerous applications. Extrapulmonary effects following pulmonary exposure have been identified and may involve reactive oxygen species (ROS). The goal of this study was to determine the extent of ROS involvement on cardiac function and the mitochondrion following nano-TiO2 exposure. To address this question, we utilized a transgenic mouse model with overexpression of a novel mitochondrially-targeted antioxidant enzyme (phospholipid hydroperoxide glutathione peroxidase; mPHGPx) which provides protection against oxidative stress to lipid membranes. MPHGPx mice and littermate controls were exposed to nano-TiO2 aerosols (Evonik, P25) to provide a calculated pulmonary deposition of 11 µg/mouse. Twenty-four hours following exposure, we observed diastolic dysfunction as evidenced by E/A ratios greater than 2 and increased radial strain during diastole in wild-type mice (p < 0.05 for both), indicative of restrictive filling. Overexpression of mPHGPx mitigated the contractile deficits resulting from nano-TiO2 exposure. To investigate the cellular mechanisms associated with the observed cardiac dysfunction, we focused our attention on the mitochondrion. We observed a significant increase in ROS production (p < 0.05) and decreased mitochondrial respiratory function (p < 0.05) following nano-TiO2 exposure which were attenuated in mPHGPx transgenic mice. In summary, nano-TiO2 inhalation exposure is associated with cardiac diastolic dysfunction and mitochondrial functional alterations, which can be mitigated by the overexpression of mPHGPx, suggesting ROS contribution in the development of contractile and bioenergetic dysfunction.

[A Case of Locally Advanced Gastric Cancer - R0 Resection Was Performed by Pancreaticoduodenectomy with Portal Vein Resection Following Neoadjuvant Therapy]

A 76-year-old woman, complained of weight loss, was admitted in our hospital. After investigation, she was diagnosed with clinical Stage III B gastric cancer with invasion into the pancreas and transverse colon. After performing the staging laparoscopy and gastrojejunostomy for pyloric stenosis, she was treated with 2 courses of SOX therapy as neoadjuvant therapy, and subsequently underwent pancreaticoduodenectomy and right hemicolectomy combined with portal vein resection due to severe adhesion by the tumor. The pathological diagnosis was pT4b(colon), pN0(0/22), pM0, pStage III B. There were no findings of tumor invasion into the pancreas or the portal vein. She was discharged without any complications. She did not receive the adjuvant chemotherapy, and died of other illness at 10 months after surgery. For the locally advanced gastric cancer such as invasion to the pancreas, the extended resection as an R0 resection could be achieved more safely, by evaluating accurately the incurable factors and planning an effective strategy according to the patient's condition.

[Complete Response Achieved with Oral Anticancer Monotherapy for Unresectable Lymph Node Metastasis after Cecal Cancer Surgery - A Case Report]

We herein report an interesting case in which a complete response was achieved with oral anticancer monotherapy for unresectable lymph node metastasis after surgery for cecal cancer. A 78-year-old woman was referred to our hospital to undergo a detailed examination for anemia. The examination led to a diagnosis of cecal cancer. She underwent open right hemicolectomy combined with adjacent abdominal wall resection and reconstruction of abdominal wall defects the next month. During follow-up without adjuvant therapy at her request, right iliac lymph node metastasis was detected 5 months later. A lymphadenectomy by laparotomy was attempted 6 months later but ended as only an exploratory laparotomy because the metastatic lymph node was difficult to detach from the vascular wall. Starting the next month, oral anticancer monothera- py(TS-1, 80mg/day for 2weeks followed by 1week of rest)was started at the patient's request. Abdominal ultrasonography performed in March 2011 revealed no evidence of lymphadenopathy, and subsequent imaging tests also confirmed the absence of lymphadenopathy. The anticancer monotherapy was discontinued after 4 years of medication. The patient remains alive, after 3 years and 5 months of medication to date, without recurrence.

[A Patient with Basaloid Carcinoma of the Esophagus Removed Surgically after Pre-Operative Chemotherapy Who Developed TTP during Post-Operative Chemotherapy]

A 63-year-old man presented with the chief complaint of an unpleasant feeling in the chest after a meal.Esophagogastroduodenoscopy revealed interminglement of ulcer infiltration type lesions and protruding lesions in the lower esophagus.A large type 1 protruding lesion was located mainly in the esophagogastric junction(EGJ)and it progressed towards the stomach.A hypertrophic and protruding lesion on the lower esophageal wall and a 6 cm tumor in the major axis of the fornix were observed on thoracic and abdominal CT, and an endocrine cell carcinoma or basaloid carcinoma were suggested after biopsy.Finally, we diagnosed a basaloid carcinoma after immunohistochemistry analysis.We administered 4 courses of TS-1 plus CDDP as pre-operative chemotherapy.Because of a significant reduction in tumor size, approximately 5 months after first presentation, we performed esophageal resection by right thoracotomy and laparotomy, and reconstructive surgery for the thoracic gastric duct.The pathological diagnosis was basaloid carcinoma with multiple foci of squamous cell carcinoma.After surgery, we continued chemotherapy with TS-1 plus CDDP, which was previously effective, but a liver metastasis appeared 8 months later.We discontinued chemotherapy because of a prominent decline in platelets.Because of the clinical symptoms, we diagnosed secondary thrombotic thrombocytopenic purpura accompanied by a malignant tumor.We implemented plasma exchange and steroid pulse therapy, but this patient experienced no therapeutic effect and died.

Maternal exposure to nanosized titanium dioxide suppresses embryonic development in mice

Although nanoscale titanium dioxide (nano-TiO2) has been extensively used in industrial food applications and daily products for pregnant women, infants, and children, its potential toxicity on fetal development has been rarely studied. The main objective of this investigation was to establish the effects of maternal exposure of nano-TiO2 on developing embryos. Female imprinting control region mice were orally administered nano-TiO2 from gestational day 0 to 17. Our findings showed that Ti concentrations in maternal serum, placenta, and fetus were increased in nano-TiO2-exposed mice when compared to controls, which resulted in reductions in the contents of calcium and zinc in maternal serum, placenta, and fetus, maternal weight gain, placental weight, fetal weight, number of live fetuses, and fetal crown-rump length as well as cauda length, and caused an increase in the number of both dead fetuses and resorptions. Furthermore, maternal nano-TiO2 exposure inhibited development of the fetal skeleton, suggesting a significant absence of cartilage, reduced or absent ossification, and an increase in the number of fetuses with dysplasia, including exencephaly, spina bifida, coiled tail, scoliosis, rib absence, and sternum absence. These findings indicated that nano-TiO2 can cross the blood-fetal barrier and placental barrier, thereby delaying the development of fetal mice and inducing skeletal malformation. These factors may be associated with reductions in both calcium and zinc in maternal serum and the fetus, and both the placenta and embryos may be major targets of developmental toxicity following maternal exposure to nano-TiO2 during the prenatal period. Therefore, the application of nano-TiO2 should be carried out with caution.

Effects of Different Concentrations and Excipients of Titanium Tetrafluoride on Dentin Erosion Prevention

PURPOSE

To evaluate the preventive effect of titanium fluoride (TiF4) gel and solution, in different concentrations, on dentin erosion.

MATERIALS AND METHODS

Of 140 root dentin slabs (3 x 3 x 1 mm) cut from 70 freshly extracted human third molars, 70 with intermediate Knoop microhardness and lowest surface curvature were selected and randomly divided into 7 groups (n = 10): G1: negative control (no treatment); G2: positive control (AmF/NaF/SnCl2 solution); G3: placebo gel (no fluoride); G4: 1% TiF4 solution; G5: 1% TiF4 gel; G6: 4% TiF4 solution; G7: 4% TiF4 gel. Samples were subjected to 10 days of erosive cycling, consisting of alternating exposures to citric acid (0.05 M, pH 2.3, 2 min, 6x/day) and remineralizing solution (pH 7.0, 90 min, between acid exposures). Each cycle consisted of a total of 6 immersions in acid per day. After 5 and 10 days of pH cycling, surface loss was assessed by optical profilometry (µm).

RESULTS

One-way ANOVA and Tukey's test (p < 0.05) showed that after 5 days, G7 revealed a significant reduction in surface loss compared to the other groups, while G4, G5 and G6 did not differ significantly from G1. After 10 days of erosive challenges, G7 did not differ significantly from G2 and there was no difference between G4, G5, G6 and G1. G3 showed the highest surface loss compared to all groups, except G1 and G5.

CONCLUSION

The treatments tested were not able to prevent dentinal erosion, but the application of 4% TiF4 gel did reduce surface loss of dentin.

Titanium Dioxide Nanoparticles as Radiosensitisers: An In vitro and Phantom-Based Study

Objective: Radiosensitisation caused by titanium dioxide nanoparticles (TiO2-NPs) is investigated using phantoms (PRESAGE® dosimeters) and in vitro using two types of cell lines, cultured human keratinocyte (HaCaT) and prostate cancer (DU145) cells. Methods: Anatase TiO2-NPs were synthesised, characterised and functionalised to allow dispersion in culture-medium for in vitro studies and halocarbons (PRESAGE® chemical compositions). PRESAGE® dosimeters were scanned with spectrophotometer to determine the radiation dose enhancement. Clonogenic and cell viability assays were employed to determine cells survival curves from which the dose enhancement levels "radiosensitisation" are deduced. Results: Comparable levels of radiosensitisation were observed in both phantoms and cells at kilovoltage ranges of x-ray energies (slightly higher in vitro). Significant radiosensitisation (~67 %) of control was also noted in cells at megavoltage energies (commonly used in radiotherapy), compared to negligible levels detected by phantoms. This difference is attributed to biochemical effects, specifically the generation of reactive oxygen species (ROS) such as hydroxyl radicals (•OH), which are only manifested in aqueous environments of cells and are non-existent in case of phantoms. Conclusions: This research shows that TiO2-NPs improve the efficiency of dose delivery, which has implications for future radiotherapy treatments. Literature shows that Ti2O3-NPs can be used as imaging agents hence with these findings renders these NPs as theranostic agents.

Chronic nasal exposure to nanoparticulate TiO2 causes pulmonary tumorigenesis in male mice

Chronic inhalation bioassays in rodents are used to assess pulmonary carcinogenicity for purposes of hazard identification and potentially for risk characterization. Numerous studies have been confirmed that exposure to titanium dioxide nanoparticles (TiO₂ NPs) may result in chronic pulmonary inflammation in both mice and rats. However, very few studies have focused on the pulmonary tumorigenesis. In this study, to examine whether chronic TiO₂ NP exposure induce tumorigenesis in the lung, forty mice (each group) were nasally exposed to 1.25, 2.5, and 5 mg/kg body weight TiO₂ NPs for nine consecutive months, lung pathology was then evaluated, and the biochemical function parameters in bronchoalveolar lavage (BAL) and tumor markers in the serum were investigated using an ELISA method. We observed that nasal exposure to TiO₂ NPs caused infiltration of inflammatory cells, tumorigenesis in the lung, and accompanied by significant increases of lactate dehydrogenase, alkaline phosphatase, and total protein levels in BLAF, significant increases in tumor markers including cytokeratin 19, neuron-specific enolase, carcinoembryonic antigen, squamous cell carcinoma antigen, and cancer antigen-125 in the serum. It implies that chronic inhaled TiO₂ NPs may increase possibility of pulmonary tumor formation for human. Therefore, the production and application of TiO₂ NPs should be paid more attention. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1651-1657, 2017.

Simulated Sunlight-Mediated Photodynamic Therapy for Melanoma Skin Cancer by Titanium-Dioxide-Nanoparticle-Gold-Nanocluster-Graphene Heterogeneous Nanocomposites

Simulated sunlight has promise as a light source able to alleviate the severe pain associated with patients during photodynamic therapy (PDT); however, low sunlight utilization efficiency of traditional photosensitizers dramatically limits its application. Titanium-dioxide-nanoparticle-gold-nanocluster-graphene (TAG) heterogeneous nanocomposites are designed to efficiently utilize simulated sunlight for melanoma skin cancer PDT. The narrow band gap in gold nanoclusters (Au NCs), and staggered energy bands between Au NCs, titanium dioxide nanoparticles (TiO₂ NPs), and graphene can result in efficient utilization of simulated sunlight and separation of electron-hole pairs, facilitating the production of abundant hydroxyl and superoxide radicals. Under irradiation of simulated sunlight, TAG nanocomposites can trigger a series of toxicological responses in mouse B16F1 melanoma cells, such as intracellular reactive oxygen species production, glutathione depletion, heme oxygenase-1 expression, and mitochondrial dysfunctions, resulting in severe cell death. Furthermore, intravenous or intratumoral administration of biocompatible TAG nanocomposites in B16F1-tumor-xenograft-bearing mice can significantly inhibit tumor growth and cause severe pathological tumor tissue changes. All of these results demonstrate prominent simulated sunlight-mediated PDT effects.

A New Green Titania with Enhanced NIR Absorption for Mitochondria-Targeted Cancer Therapy

A new kind of green titania (G-TiO2-x ) with obvious green color was facilely synthesized from black titania (B-TiO2-x ) through subsequently strong ultrasonication. Comparatively, this stable G-TiO2-x shows much enhanced near infrared (NIR) absorption, especially around 920 nm, which can be ascribed to the obvious change of TiO2-x lattice order owing to the effect of ultrasonication. This feature enables G-TiO2-x to be stimulated with 980 nm laser in the combined photodynamic therapy (PDT) and photothermal therapy (PTT), which is greatly beneficial for improving tissue penetration depth. Furthermore, since mitochondria are preferred subcellular organelles for PDT/PTT, G-TiO2-x was further designed to conjugate with triphenylphosphonium (TPP) ligand for mitochondria-targeted PDT/PTT to obtain precise cancer treatment. Attributing to the high mitochondria-targeting efficiency and simultaneously synergistic PDT/PTT, high phototherapeutic efficacy and safety with a much lower laser power density (980 nm, 0.72 W cm-2) and low materials dosage were achieved both in vitro and in vivo. In addition, negligible toxicity was found, indicating high biocompatibility. This novel G-TiO2-x could provide new strategies for future precise minimal/non-invasive tumor treatment.

Inhibitory effect of TiO2 NPs on symbiotic arbuscular mycorrhizal fungi in plant roots

While nanoparticles (NPs) are known to exhibit antimicrobial properties, their effects on symbiotic arbuscular mycorrhizal fungi (AMF) in plant roots has to be carefully examined as NPs particularly of titanium dioxide (TiO2) reach plant roots through varied sources such as fertilisers, plant protection products and other nanoproducts. The objective of the present study is to assess the effect of TiO2 NPs on the symbiotic behaviour of AMF colonising rice (Oryza sativa L.) plants. Using sol-gel method, TiO2 NPs with three different sizes were successfully synthesised employing doping. Characterisation of the prepared material was done by X-ray powder diffraction and scanning electron microscopy. The synthesised materials were applied at 0, 25, 50 and 100 mg plant-1 to the rhizosphere of mycorrhizal rice plants maintained in pots. The study revealed that the prepared NPs had an inhibitory effect on arbuscular mycorrhizal symbiosis in plant roots. Development of AMF structures such as vesicles and arbuscules was significantly reduced in TiO2-doped NPs with a relatively more inhibition in 2% TiO2-doped NPs. Among the concentrations of TiO2 NPs applied to different treatments, %F was significantly (P < 0.001) affected at medium to higher levels of application.

Bone tissue response induced by bioactive polymer functionalized Ti6Al4V surfaces: In vitro and in vivo study

Ti6Al4V is commonly used for orthopedic applications. This study was designed to test the potentially added benefit of Ti6Al4V functionalized with a bioactive polymer poly(sodium styrene sulfonate) both in vitro and in vivo. Cell-based assays with MC3T3-E1 osteoblast-like cells were used to measure the cell adhesion strength, cell spreading, focal contact formation, cell differentiation and the mineralization of extracellular matrix on grafted and ungrafted Ti6Al4V discs in combination with FBS and collagen type I. Bone morphogenetic protein-2 (BMP-2) was also included in the cell differentiation assay. Results showed that the grafted surface combined with collagen I gave superior levels in every parameter tested with cell-based assays and was almost equivalent to BMP-2 for cell differentiation. In vivo testing was conducted in rabbits (n=42) with cylinders of grafted and ungrafted Ti6Al4V implanted in defects made to the femoral and lateral condyles and animals that were maintained to 1, 3 and 12months. Hydroxyapatite coated Ti6Al4V cylinders were included as a clinical reference control. Osseointegration was assessed post-mortem using histomorphometric analysis conducted on resin sections of explanted undecalcified bone. Two histomorphometric parameters, that of bone-to-implant contact and the bone area, were analyzed by a trained observer blinded to sample identity. Results showed osseointegration on grafted Ti6Al4V was marginally better than both ungrafted and hydroxyapatite coated Ti6Al4V. Overall, the study found that the grafted Ti6Al4V significantly promoted all aspects of osteogenesis tested in vitro and, although in vivo outcomes were less compelling, histomorphometry showed osseointegration of grafted Ti6Al4V implants was equivalent or better than controls.

Pulmonary responses in rat lungs after intratracheal instillation of 4 crystal forms of titanium dioxide nanoparticles

OBJECTIVE

Titanium dioxide nanoparticles are widely used as UV filters in cosmetics and as a photocatalyst. We evaluated pulmonary responses to different crystal forms of TiO2 nanoparticles.

METHODS

We used 4 different TiO2 samples with similar specific surface areas (anatase, rutile, amorphous, and P25). Each sample was suspended in distilled water and intratracheally instilled to male Wister rats at the dose of 1 mg per rat. Five rats per group were sacrificed at 3 days, 1 month, and 6 months after instillation, and bronchoalveolar lavage fluid was collected from the right lung to determine the total cell count and polymorphonuclear cell (PMN) counts. The left lung tissues were stained with hematoxylin and eosin for the evaluation of inflammation and with elastica van Gieson for the evaluation of collagen deposition.

RESULTS

The total cell counts and PMN counts of the amorphous and P25 of four samples showed a significant increase compared with the control group at 3 days after instillation. The inflammation rate of P25 also showed a significant increase compared with controls at 3 days. The collagen deposition rate in the alveolar duct of P25 increased significantly compared with controls from 3 days to 6 months. The other samples showed a mild response after instillation.

CONCLUSION

Although the TiO2 nanoparticles used in this study had similar specific surface areas, there were different inflammatory responses in the rat lungs. Other factors, such as different production processes or the surface activities of particles, may have been responsible for the different responses.

[A Case of Surgical Resection for Gallbladder Cancer with Para-Aortic Lymph Node Metastasis Following Neoadjuvant Chemotherapy with Gemcitabine, Cisplatin, and TS-1]

A 60-year-old woman who visited a doctor during postoperative follow-up for breast cancer was found to have elevated CEA levels. Investigation with FDG-PET CT following enhanced CT suggested gallbladder cancer(GBC)accompanied with para-aortic lymph node(PAL)metastasis. Although we could not obtain any histological evidence, we recommended she be treated as a patient with advanced GBC, and she received 8 courses of chemotherapy consisting of gemcitabine, cisplatin, and TS-1, following the protocol of a clinical trial. After the chemotherapy, imaging exhibited down-staging of the GBC, indicating tumor shrinkage and disappearance of the accumulation of FDG at the tumor sites. We first performed cholecystectomy to obtain histological evidence, and subsequently performed pancreaticoduodenectomy and partial hepatectomy at the gallbladder bed. The pathological diagnosis was pT2N1M0, Stage III B, Evans Grade II b; curative grade A surgery was recommended because the PAL did not contain a tumor any more. The prognosis of advanced GBC with PAL metastasis is extremely poor, but conversion therapy with combined modality therapy including neoadjuvant chemotherapy is a useful strategy to achieve a curative resection.

[A Case of a-Fetoprotein Producing Gastric Cancer with Lymph Node Recurrence after Endoscopic Submucosal Dissection]

A 70-year-old man underwent endoscopic submucosal dissection(ESD)for 2 early-stage gastric cancers in 2009 and 2014, respectively. Both were pathologically diagnosed after curative resection. In 2015, we detected swollen lymph nodes in the lesser curvature of the stomach on computed tomography(CT). PET-CT revealed that the swollen lymph nodes showed an abnormal uptake of fluorodeoxyglucose; therefore, we considered the possibility of metastatic recurrence of the gastric can- cer. The patient's serum a-fetoprotein(AFP)level was elevated to 30.6 ng/mL. The intraoperative pathological diagnosis of the swollen lymph node was tub2. We diagnosed this case as metastatic recurrence of gastric cancer and performed distal gastrectomy with lymph node dissection. Metastases were found in 3 of the resected lymph nodes. Immunohistochemical staining for AFP was positive in the specimens obtained via ESD in 2014 and in the metastatic lymph nodes. We diagnosed the patient with AFP-producing gastric cancer. On additional trimming of the specimen obtained via ESD in 2014, we found slight lymphatic invasion.

TiO2 nanotube platforms for smart drug delivery: a review

Titania nanotube (TNT) arrays are recognized as promising materials for localized drug delivery implants because of their excellent properties and facile preparation process. This review highlights the concept of localized drug delivery systems based on TNTs, considering their outstanding biocompatibility in a series of ex vivo and in vivo studies. Considering the safety of TNT implants in the host body, studies of the biocompatibility present significant importance for the clinical application of TNT implants. Toward smart TNT platforms for sustainable drug delivery, several advanced approaches were presented in this review, including controlled release triggered by temperature, light, radiofrequency magnetism, and ultrasonic stimulation. Moreover, TNT implants used in medical therapy have been demonstrated by various examples including dentistry, orthopedic implants, cardiovascular stents, and so on. Finally, a future perspective of TNTs for clinical applications is provided.

Visceral fat increase and signals of inflammation in adipose tissue after administration of titanium dioxide nanoparticles in mice

Titanium dioxide nanoparticles (TiO₂ NP) are present in several daily use products, and the risks associated with their bioaccumulation must be stablished. Thus, an evaluation of several toxicological-related effects was conducted after intraperitoneal injection of TiO₂ NPs in mice. Mice were divided into two groups, which received 2 mg kg^-1 day^-1 of TiO₂ NPs or vehicle saline. Assessments of body and organ weight as well as biochemical, hematological, and histopathological analyses were performed in order to evaluate adverse effects. The results showed that treatment resulted in an increased visceral and abdominal fat deposition, as well as a mononuclear inflammatory infiltrates in the abdominal fat tissue. The TiO₂ NPs induced significant decrease in the weight gain and splenomegaly. Additionally, TiO₂ NP-treated mice showed altered hematological parameters and significant liver injuries, which were characterized by histopathological and biochemical changes. Our results also indicated that TiO₂ NPs were absorbed and significantly accumulated in the spleen, liver, and kidney. These results showed the ability of TiO₂ NPs to infiltrate different organs and to induce inflammation and liver and spleen damage with visceral fat accumulation. The data obtained are useful for the governmental authorities to legislate and implement regulations concerning the use and the production of this kind of material that might be hazardous to the living beings, as well as to the environment.