Mitochondria Play Essential Roles in Intracellular Protection against Oxidative Stress-Which Molecules among the ROS Generated in the Mitochondria Can Escape the Mitochondria and Contribute to Signal Activation in Cytosol?

Questions about which reactive oxygen species (ROS) or reactive nitrogen species (RNS) can escape from the mitochondria and activate signals must be addressed. In this study, two parameters, the calculated dipole moment (debye, D) and permeability coefficient (Pm) (cm s-1), are listed for hydrogen peroxide (H2O2), hydroxyl radical (•OH), superoxide (O2•-), hydroperoxyl radical (HO2•), nitric oxide (•NO), nitrogen dioxide (•NO2), peroxynitrite (ONOO-), and peroxynitrous acid (ONOOH) in comparison to those for water (H2O). O2•- is generated from the mitochondrial electron transport chain (ETC), and several other ROS and RNS can be generated subsequently. The candidates which pass through the mitochondrial membrane include ROS with a small number of dipoles, i.e., H2O2, HO2•, ONOOH, •OH, and •NO. The results show that the dipole moment of •NO2 is 0.35 D, indicating permeability; however, •NO2 can be eliminated quickly. The dipole moments of •OH (1.67 D) and ONOOH (1.77 D) indicate that they might be permeable. This study also suggests that the mitochondria play a central role in protecting against further oxidative stress in cells. The amounts, the long half-life, the diffusion distance, the Pm, the one-electron reduction potential, the pKa, and the rate constants for the reaction with ascorbate and glutathione are listed for various ROS/RNS, •OH, singlet oxygen (1O2), H2O2, O2•-, HO2•, •NO, •NO2, ONOO-, and ONOOH, and compared with those for H2O and oxygen (O2). Molecules with negative electrical charges cannot directly diffuse through the phospholipid bilayer of the mitochondrial membranes. Short-lived molecules, such as •OH, would be difficult to contribute to intracellular signaling. Finally, HO2• and ONOOH were selected as candidates for the ROS/RNS that pass through the mitochondrial membrane.

Enhancement of cytotoxic effects with ALA-PDT on treatment of radioresistant cancer cells

Radiation therapy is a lower invasive local treatment than surgery and is selected as a primary treatment for solid tumors. However, when some cancer cells obtain radiotherapy tolerance, cytotoxicity of radiotherapy for cancer cells is attenuated. Photodynamic therapy (PDT) is a non-invasive cancer therapy combined with photosensitizers and laser irradiation with an appropriate wavelength. PDT is carried out for recurrent esophageal cancer patients after radiation chemotherapy and is an effective treatment for radiation-resistant tumors. However, it is not clear why PDT is effective against radioresistant cancers. In this study, we attempted to clear this mechanism using X-ray resistant cancer cells. X-ray resistant cells produce high amounts of mitochondria-derived ROS, which enhanced nuclear translocation of NF-κB, resulting in increased NO production. Moreover, the expression of PEPT1 that imports 5-aminolevulinic acid, the precursor of photosensitizers, was upregulated in X-ray resistant cancer cells. This was accompanied by an increase in intracellular 5-aminolevulinic acid-derived porphyrin accumulation, resulting in enhancement of PDT-induced cytotoxicity. Therefore, effective accumulation of photosensitizers induced by ROS and NO may achieve PDT after radiation therapy and PDT could be a promising treatment for radioresistant cancer cells.

Polphylipoprotein-induced autophagy mechanism with high performance in photodynamic therapy

Polphylipoprotein (PLP) is a recently developed nanoparticle with high biocompatibility and tumor selectivity, and which has demonstrated unprecedentedly high performance photosensitizer in photodynamic therapy (PDT) and photodynamic diagnosis. On the basis of these discoveries, PLP is anticipated to have a very high potential for PDT. However, the mechanism by which PLP kills cancer cells effectively has not been sufficiently clarified. To comprehensively understand the PLP-induced PDT processes, we conduct multifaceted experiments using both normal cells and cancer cells originating from the same sources, namely, RGM1, a rat gastric epithelial cell line, and RGK1, a rat gastric mucosa-derived cancer-like mutant. We reveal that PLP enables highly effective cancer treatment through PDT by employing a unique mechanism that utilizes the process of autophagy. The dynamics of PLP-accumulated phagosomes immediately after light irradiation are found to be completely different between normal cells and cancer cells, and it becomes clear that this difference results in the manifestation of the characteristic effect of PDT when using PLP. Since PLP is originally developed as a drug delivery agent, this study also suggests the potential for intracellular drug delivery processes through PLP-induced autophagy.

Singlet oxygen-generating cell-adhesive glass surfaces for the fundamental investigation of plasma membrane-targeted photodynamic therapy

Recently, plasma membrane-targeted photodynamic therapy has attracted attention as an effective cancer immunotherapeutic strategy. However, the released photosensitizers do not only adhere to the plasma membrane but may also be internalized in the cytosol, in endosomes/lysosomes, hindering investigations of the effects of photosensitizers attached to the plasma membrane. In this study, we developed a cell culture dish with singlet oxygen-generating cell-adhesive glass surfaces that allows investigation of the effects of photosensitizers attached to the plasma membrane. For cell adhesion, poly[N-(3-aminopropyl)methacrylamide] conjugated with hematoporphyrin PA-HpD was immobilized on the glass surfaces. Singlet oxygen was produced from the PA-HpD-immobilized glass surface upon laser irradiation at 635 nm. When murine colon adenocarcinoma 26 (Colon-26) cells were cultured on the PA-HpD-immobilized surface, the cells were swollen and ruptured, leading to effective apoptotic cell death using laser irradiation at 635 nm. In addition, microvesicles of approximately 10 μm in diameter were released from the plasma membrane into the culture medium. These phenomena were due to the oxidation of lipids in the cellular membrane, caused by the plasma membrane-targeted photodynamic therapy. In contrast, these phenomena were not observed on poly[N-(3-aminopropyl)methacrylamide]-immobilized glass surfaces. These results indicate that cell culture dishes with singlet oxygen-generating cell-adhesive glass surfaces can be used to investigate fundamental mechanisms in plasma membrane-targeted photodynamic therapy.

Locally Administered Photodynamic Therapy for Cancer Using Nano-Adhesive Photosensitizer

Photodynamic therapy (PDT) is a great potential anti-tumor therapy owing to its non-invasiveness and high spatiotemporal selectivity. However, systemically administered photosensitizers diffuse in the skin and the eyes for a long duration, which cause phototoxicity to bright light and sunlight. Therefore, following PDT, patients must avoid exposure of to light and sunlight to avoid this phototoxicity. In this study, we have developed a locally administered PDT using nano-adhesive porphyrin with polycations consisting of quaternary ammonium salt groups (aHP) as a photosensitizer. The aHP, approximately 3.0 nm in diameter, adhered the negatively charged cell membrane via electrostatic interaction. The aHP localized to the endosome via cell adhesion and induced apoptosis upon 635 nm light irradiation. On being administered subcutaneously on the tumor, 30% of the injected aHP remained in the administered sites. However, low-molecular-weight hematoporphyrin dihydrochloride (HP) disappeared due to rapid diffusion. PDT with locally administered aHP showed a higher anti-tumor effect after light irradiation at 635 nm for three days compared to low-molecular-weight HP. Intraperitoneal administration of HP caused severe phototoxicity upon irradiation with ultraviolet A at 10 J cm-2, whereas aHP did not cause phototoxicity because its diffusion into the skin could be suppressed, probably due to the high-molecular weight of aHP. Therefore, locally administered PDT with aHP is a potential PDT having high therapeutic efficacy without phototoxicity.

Designing poly(gamma-aminobutyric acid)-based nanoparticles for the treatment of major depressive disorders

Major depressive disorder (MDD) is a worldwide concern owing to its negative impact on the quality of life. Gamma-aminobutyric acid (GABA), an essential neurotransmitter in the brain, is important for regulating the enteric nervous system and gut-brain dual communication (gut-brain axis), thus providing gastrointestinal GABA and GABA-related pathways with possible targets for MDD treatment. However, the use of GABA for this disease remains limited due to its poor pharmacokinetic properties, including the low permeability through the blood-brain barrier, and the rapid clearance from the gastrointestinal tract. Since poly(amino acid)s are advantageous for improving the beneficial bioactivities of conventional amino acids, poly(gamma-aminobutyric acid) (poly(GABA)) is a potential candidate for MDD therapy. Nevertheless, the non-water-soluble and non-dispersible characteristics of poly(GABA) render difficulty in administering its conventional forms in vitro/in vivo, thereby hindering its therapeutic applications. Therefore, this study proposes a new design for poly(GABA) in nanoparticle form, which is composed of the amphiphilic diblock copolymers of poly(GABA) and poly(ethylene glycol), providing a suitable formulation for medication applications. Herein, we report on a new orally deliverable poly(GABA)-based nanoparticles (NanoGABA) in aqueous media and their efficacy on mouse depression models. NanoGABA treatment efficiently attenuated depression-like symptoms as evidenced by behavioral tests (forced swimming tests and tail suspension tests) and stress biomarkers (corticosterone). These findings suggest that the newly designed poly(GABA)-based nanoparticles are a promising candidate for the treatment of depression. STATEMENT OF SIGNIFICANCE: This research is the first to report the preparation of poly(GABA)-based nanoparticles in aqueous conditions with beneficial physical properties to open the gate for medical and pharmaceutical applications of poly (GABA). It is also a pioneer in using poly(GABA)-based materials for major depressive disorder therapeutics in vivo. Oral administration of NanoGABA attenuates depressive-like symptoms by targeting the enteric nervous system possibly through modulation of the gut-brain axis pathways with negligible toxicity, suggesting that NanoGABA is a promising therapeutic agent for major depressive disorders.

Therapeutic Potential of Seaweed-Derived Laminaran: Attenuation of Clinical Drug Cytotoxicity and Reactive Oxygen Species Scavenging

β-glucan has been shown to be effective for several diseases such as immune regulation and blood pressure suppression. Seaweed contains a β-1,3/1,6-glucan called laminaran. The present commercial source of β-glucan is black yeast; however, a fermentation process using organic carbon substrates makes production unsustainable, whereas macroalgae provide a sustainable alternative with the use of CO₂ and seawater as growth substrates. However, bioactivity studies on laminaran are limited. We aimed to evaluate whether laminaran can scavenge reactive oxygen species (ROS) and attenuate cytotoxicity caused by clinical drugs such as indomethacin (Ind) and dabigatran (Dab). Electron spin resonance assay revealed that laminaran scavenged singlet oxygen (¹O₂) and superoxide anions (O₂^•-) directly but did not scavenge hydroxyl radicals (^•OH). Mitochondrial ROS detection dye showed that laminaran scavenged mitochondrial O₂^•- produced upon administration of Ind or Dab. Moreover, significant reductions in ^•OH and peroxynitrate (ONOO^-) levels were observed. Since ^•OH and ONOO^- are generated from O₂^•- in the cells, laminaran could indirectly suppress the generation of ^•OH and ONOO^- via the removal of O₂^•-. Both Ind and Dab induce cell injury via ROS production. Laminaran attenuated the cytotoxicity derived from these drugs and may represent a functional food with anti-aging and disease prevention properties.

Automated cell isolation from photodegradable hydrogel based on fluorescence image analysis

We report an automated cell-isolation system based on fluorescence image analysis of cell aggregates cultured in a photodegradable hydrogel. The system incorporates cell culture in a humidified atmosphere with controlled CO₂ concentration and temperature, image acquisition and analysis, micropatterned light exposure, and cell collection by pipetting. Cell aggregates were cultured on hydrogels, and target cells were selected by phase contrast and fluorescence image analysis. After degradation of the hydrogel by exposure to micropatterned ultraviolet light, cell aggregates were transferred to a collection vessel by robotic pipetting. We assessed the system for hydrogel degradation, recovery of target cells, and contamination by off-target cells. We demonstrated two practical applications of our method: (i) in cell aggregates from MCF-7-RFP strains in which 18.8% of cells produced red fluorescent protein (RFP), we successfully obtained 14 proliferative fluorescence-positive cell aggregates from 31 wells, and all of the isolated strains produced a higher proportion of RFP production than the original populations; (ii) after fluorescent immunostaining of human epidermal growth factor receptor 2 (HER2) in cancer cells, we successfully isolated HER2-positive cells from a mixed population of HER2-positive and -negative cells, and gene sequence analysis confirmed that the isolated cells mainly contained the target cells. This article is protected by copyright. All rights reserved.

Evidence of Nrf2/Keap1 Signaling Regulation by Mitochodria-Generated Reactive Oxygen Species in RGK1 Cells

It has been known that reactive oxygen species (ROS) are generated from the mitochondrial electron transport chain (ETC). Majima et al. proved that mitochondrial ROS (mtROS) caused apoptosis for the first time in 1998 (Majima et al. J Biol Chem, 1998). It is speculated that mtROS can move out of the mitochondria and initiate cellular signals in the nucleus. This paper aims to prove this phenomenon by assessing the change in the amount of manganese superoxide dismutase (MnSOD) by MnSOD transfection. Two cell lines of the same genetic background, of which generation of mtROS are different, i.e., the mtROS are more produced in RGK1, than in that of RGM1, were compared to analyze the cellular signals. The results of immunocytochemistry staining showed increase of Nrf2, Keap1, HO-1 and 2, MnSOD, GCL, GST, NQO1, GATA1, GATA3, GATA4, and GATA5 in RGK1 compared to those in RGM1. Transfection of human MnSOD in RGK1 cells showed a decrease of those signal proteins, suggesting mtROS play a role in cellular signals in nucleus.

Different nanobubbles mitigate cadmium toxicity and accumulation of rice (Oryza sativa L.) seedlings in hydroponic cultures

Cadmium (Cd) contamination can pose a severe threat to food production and human health. The accumulation of Cd in rice will decrease rice biomass, photosynthetic activity, and antioxidant capacity, affecting crop yield. The effects of different nanobubbles on the growth and Cd accumulation of rice seedlings under hydroponic conditions were investigated in this study. The results showed that the biomass, photosynthetic pigment content, and antioxidant enzyme activity of rice seedlings decreased when treated with Cd alone and that Cd induced lipid peroxidation in rice seedlings. However, when different types of nanobubbles were introduced into the nutrient solution, the bioavailability of Cd in the solution was reduced. As a result, the Cd content in rice was significantly decreased compared to treatment with Cd alone. Nanobubbles increased the biomass of rice, enhanced photosynthesis, and improved the antioxidant capacity of rice by increasing antioxidant enzyme activities to alleviate Cd-induced oxidative stress. At the same time, nanobubbles increased the Fe content in rice, which decreased the Cd content, as Cd is antagonistic to Fe. In conclusion, these results suggested that nanobubbles are a potential method of mitigating Cd stress that may help to improve rice yield and could be further explored in production.

Financial incentives for infection prevention and antimicrobial stewardship to reduce antibiotic use: Japan's nationwide observational study

BACKGROUND

The Japanese government introduced financial incentives to reduce nationwide antibiotic use in hospital settings.

AIM

This study aimed to determine whether the nationwide financial incentives for creating infection prevention and control (IPC) teams introduced in 2012 and antimicrobial stewardship (ASP) teams introduced in 2018 were associated with changes in antibiotic use and health resource utilization at a national level.

METHODS

We conducted time-series analyses and a difference-in-differences study consisting of 3,057,517 inpatients with infectious diseases from 472 medical facilities during fiscal years 2011-2018 using a nationally representative inpatient database in Japan. The primary outcome was the days of therapy (DOT) of antibiotic use per 100 patient-days (PDs). The secondary outcomes consisted of types of antibiotic used, health resource utilization, and mortality.

RESULTS

A total of 5,201,304 financial incentives were observed during 2012-2018, which resulted in a total of 12.1 billion JPY (≈110 million USD). Time-series analyses found decreasing trends in total antibiotic use (79.3-72.5 DOTs/100 PDs (8.6% reduction)) and carbapenem use (9.0-7.0 DOTs/100 PDs (7.8% reduction)) from 2011 to 2018 without adversely affecting other healthcare outcomes (e.g., mortality). In the difference-in-differences analyses, we did not observe meaningful changes in total antibiotic use between the incentivized and unincentivized hospitals for ASP teams, except for the northern part of Japan. No dose-response relationships were observed between the amount of financial incentives and reductions in antibiotic use during 2011-2019.

CONCLUSIONS

Further research and efforts are needed to accelerate antimicrobial stewardship in hospital settings in Japan.

Acetic acid enhances the effect of photodynamic therapy in gastric cancer cells via the production of reactive oxygen species

Acetic acid is a major component of vinegar and is reported to have beneficial health effects. Notably, it causes oxidative stress and enhances the production of reactive oxygen species (ROS) in gastric cancer cells. ROS play important roles in cellular signal transduction, resulting in the regulation of protein expression and apoptosis. We previously reported that ROS upregulate heme carrier protein 1 (HCP1). Moreover, ROS increase the cellular uptake of porphyrins, which are precursors of heme and substrates for uptake by HCP1. Therefore, we hypothesized that photodynamic therapy (PDT) for cancer treatment using laser irradiation and photosensitizers, such as porphyrin, is enhanced via ROS produced by acetic acid. Herein, we used the rat gastric mucosal cells, RGM1, its cancer-like mutated cells, RGK1, and a manganese superoxide dismutase (MnSOD)-overexpressing RGK cell line, RGK-MnSOD. We confirmed that cancer-specific cellular uptake of porphyrin is increased upon acetic acid treatment and enhances the PDT cytotoxicity in RGK-1, not in RGM-1 and RGK-MnSOD. We believe that this occurs because of the overproduction of ROS and subsequent upregulation of HCP1 in cancerous cells. In conclusion, acetic acid can elevate the effect of PDT by inducing cancer-specific HCP1 expression via ROS production.

Direct analysis of the actin-filament formation effect in photodynamic therapy

Photodynamic therapy (PDT) is a method in which a photosensitizer is administered in vivo and irradiated with light to generate reactive oxygen species (ROS), thereby causing the selective death of cancer cells. Since PDT is a noninvasive cancer treatment method with few adverse effects, it has attracted considerable attention and is increasingly used. In PDT, there are two dominant processes based on the actin filament (A-filament) formation effect: the destruction of cells by necrosis and vascular shutdown. Despite the importance of its fine control, the mechanism of the reaction process from the generation of reactive oxygen by photoinduction inducing the formation of A-filament and its polymerization to form stress fibers (S-fibers) has not yet been clarified because, for example, it has been difficult to directly observe and quantify such processes in living cells by conventional methods. Here, we have combined atomic force microscopy (AFM) with other techniques to reveal the mechanism of the A-filament and S-fiber formation processes that underlie the cell death process due to PDT. First, it was confirmed that activation of the small G protein RhoA, which is a signal that induces an increase in A-filament production, begins immediately after PDT treatment. The production of A-filament did not increase with increasing light intensity when the amount of light was large. Namely, the activation of RhoA reached an equilibrium state in about 1 min: however, the production of A-filament and its polymerization continued. The observed process corresponds well with the change in the amount of phosphorylated myosin-light chains, which induce A-filament polymerization. The increase in the elastic modulus of cells following the formation of S-fiber was confirmed by AFM for the first time. The distribution of generated A-filament and S-fiber was consistent with the photosensitizer distribution. PDT increases A-filament production, and when the ROS concentration is high, blebbing occurs and cells die, but when it is low, cell death does not occur and S-fiber is formed. That is, it is expected that vascular shutdown can be controlled efficiently by adjusting the amount of photosensitizer and the light intensity.

We have combined atomic force microscopy with other techniques to reveal the mechanism of the actin filament and stress fibers formation processes that underlies the cell death process due to photodynamic therapy.

Near-Infrared Light Irradiation of Porphyrin-Modified Gold Nanoparticles Promotes Cancer-Cell-Specific Cytotoxicity

The use of nanoparticles has been investigated as a new cancer treatment. These can induce specific cytotoxicity in cancer cells. In particular, Au nanoparticles (AuNPs) have unique characteristics. The maximum absorption spectrum of AuNPs can be adjusted to modify their size or shape to absorb near-infrared light that can penetrate into tissue without photodamage. Thus, the combination of AuNPs and near-infrared light can be used to treat cancer in deep-seated organs. To obtain effective cancer-specific accumulation of AuNPs, we focused on porphyrin and synthesized a porphyrin-attached Au compound: Au-HpD. In this study, we investigated whether Au-HpD possesses cancer-specific accumulation and cytotoxicity. Intracellular Au-HpD accumulation was higher in cancer cells than in normal cells. In order to analyze the cytotoxicity induced by Au-HpD, cancer cells and normal cells were co-cultured in the presence of Au-HpD; then, they were subjected to 870 nm laser irradiation. We observed that, after laser irradiation, cancer cells showed significant morphological changes, such as chromatin condensation and nuclear fragmentation indicative of cell apoptosis. This strong effect was not observed when normal cells were irradiated. Moreover, cancer cells underwent cell apoptosis with combination therapy.

Stability and Free Radical Production for CO2 and H2 in Air Nanobubbles in Ethanol Aqueous Solution

In this study, 8% hydrogen (H₂) in argon (Ar) and carbon dioxide (CO₂) gas nanobubbles was produced at 10, 30, and 50 vol.% of ethanol aqueous solution by the high-speed agitation method with gas. They became stable for a long period (for instance, 20 days), having a high negative zeta potential (−40 to −50 mV) at alkaline near pH 9, especially for 10 vol.% of ethanol aqueous solution. The extended Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory was used to evaluate the nanobubble stability. When the nanobubble in ethanol alkaline aqueous solution changed to an acidic pH of around 5, the zeta potential of nanobubbles was almost zero and the decrease in the number of nanobubbles was identified by the particle trajectory method (Nano site). The collapsed nanobubbles at zero charge were detected thanks to the presence of few free radicals using G-CYPMPO spin trap reagent in electron spin resonance (ESR) spectroscopy. The free radicals produced were superoxide anions at collapsed 8%H₂ in Ar nanobubbles and hydroxyl radicals at collapsed CO₂ nanobubbles. On the other hand, the collapse of mixed CO₂ and H₂ in Ar nanobubble showed no free radicals. The possible presence of long-term stable nanobubbles and the absence of free radicals for mixed H₂ and CO₂ nanobubble would be useful to understand the beverage quality.

The cytotoxicity of cyclophosphamide is enhanced in combination with monascus pigment

Monascus pigment is derived from red-mold rice fermented by monascus purpureus and utilized as a natural coloring agent and natural food additive in East Asia. Monascus pigment works as a radical scavenger. Some antioxidant combine cancer chemo­therapy to protect normal tissue because chemotherapy induce side effect for normal tissue. This combination therapy can attenuate the cytotoxicity of anti­cancer drugs by antioxidants effects. However, the effect of this combination therapy for cancer cells dose not investigate enough. In this study, we investigated the combination effect of anti­oxidants and anti­cancer drugs. We selected an anti­oxidant as monascus pigment and following four anti­cancer drugs: doxorubicin, tamoxifen, paclitaxicel, and cyclophosphamide. Combination treatment with monascus pigment and cyclophosphamide enhanced the cytotoxicity of cyclophosphamide. Moreover, this combination treatment accelerated apoptosis. The spot on TLC assay board of the monascus pigment and cyclophosphamide mixture is different from the spot of monascus pigment alone and cyclophosphamide alone. The interaction between monascus pigment and cyclo­phosphamide can produce some cytotoxicity compounds or accelerate intracellular cyclophosphamide accumulation. Hence, we concluded that the interaction of both cyclophosphamide and monascus pigment involved enhancement of cyclophosphamide cytotoxicity.

The Cytotoxicity of Doxorubicin Can Be Accelerated by a Combination of Hyperthermia and 5-Aminolevulinic Acid

Chemotherapy is cytotoxic to various cancer cells and as well as normal cells. Thus, treatments that demonstrate selective cytotoxicity for cancer cells are desired. The combination of chemotherapy and other cancer therapies can show synergic cytotoxicity, which may be a clue to the nature of the involved cancer cellar-specific damage. We previously reported a phenomenon whereby mitochondrial reactive oxygen species (mitROS) regulate the expression transporters involved in anticancer drug transport and mitROS production is increased by hyperthermia. Moreover, the uptake of 5-aminolevulinic acid (ALA) was enhanced by the increase in mitROS production. In this study, we investigated whether the combination of hyperthermia and ALA can enhance the cytotoxicity of doxorubicin. MitROS production and ALA-derived porphyrin accumulation by hyperthermia (HT) were increased in a murine breast cancer cell line. The expression of solute carrier 15A1 (SLC15A1) upregulated and an ATP-binding cassette subfamily G member 2 (ABCG2) downregulated by HT. Since SLC15A1 is an accumulating transporter for ALA, while ABCG2 is a porphyrin efflux transporter, porphyrin accumulation was enhanced. ABCG2 is also a doxorubicin efflux transporter. Thus, ALA treatment accelerates the intracellular concentration of porphyrin, which acts as a competitive inhibitor of doxorubicin. Indeed, the amount of intracellular doxorubicin was increased by a combination of HT and ALA. The cytotoxicity of doxorubicin was also enhanced. This enhancement was observed in the human breast cancer cell line while it was not seen in normal cells. The combination of HT and ALA treatment can enhance the cancer-specific cytotoxicity of doxorubicin.

Antithrombotic Effect of the Ethanol Extract of Angelica gigas Nakai (AGE 232)

Cardiovascular diseases, such as stroke, are the most common causes of death in developed countries. Ischemic stroke accounts for 85% of the total cases and is caused by abnormal thrombus formation in the vessels, causing deficient blood and oxygen supply to the brain. Prophylactic treatments include the prevention of thrombus formation, of which the most used is acetylsalicylic acid (ASA); however, it is associated with a high incidence of side effects. Angelica gigas Nakai (AG) is a natural herb used to improve blood circulation via anti-platelet aggregation, one of the key processes involved in thrombus formation. We examined the antithrombotic effects of AGE 232, the ethanol extract of A. gigas Nakai. AGE 232 showed a significant reduction in death or paralysis in mice caused by collagen/epinephrine-induced thromboembolism in a dose-dependent manner and inhibition of collagen-induced human platelet aggregation in a concentration-dependent manner. Additionally, AGE 232-treated mice did not show severe bleeding in the gut compared to ASA-treated mice. AGE 232 resulted in a decrease in the number of neutrophils attached to the human umbilical vein endothelial cells (HUVECs) and lower inhibition of COX-1 in response to bleeding and damage to blood vessels, a major side effect of ASA. Therefore, AGE 232 can prevent thrombus formation and stroke.

Influence of Living Environment during Childhood on Helicobacter pylori Infection in Japanese Young Adults

INTRODUCTION

Helicobacter pylori infection is usually established during childhood, for which certain responsible environmental factors have been identified. However, the details of the infection routes remain unclear.

OBJECTIVE

To determine the relation between H. pylori infection statuses and living environment of Japanese young adult.

METHODS

The subjects were 449 healthy young adult medical students of Tsukuba University (299 men and 150 women, mean age: 22.8 years). The H. pylori infection statuses were investigated using the rapid urease test or urine antibody. Questionnaires regarding sanitary conditions including usage of pit toilet or well water and experience of living with one's grandparents during childhood were surveyed. Each item was compared between the H. pylori-positive and -negative groups.

RESULTS

Among all participants, 33 (7.3%) were H. pylori-positive. The usage rates of pit toilets were 12.1 and 3.1% for the H. pylori-positive and -negative groups respectively (p = 0.03; OR 4.35, 95% CI 1.33-14.22). The usage rates of well water were 24.2 and 13.7% for the H. pylori-positive and -negative groups respectively (p = 0.07; OR 2.12, 95% CI 0.91-4.98). The proportion of participants with a history of living with their grandparents was significantly greater in the H. pylori-positive group (46.7%) than in the -negative group (20.9%; p = 0.03; OR 3.28, 95% CI 1.13-9.54). Only a history of living with one's grandparents during childhood showed statistical significance in the multivariate regression analysis (p = 0.04; OR 3.20, 95% CI 1.08-9.49).

CONCLUSIONS

These results suggest that H. pylori infection is more strongly related to living with one's grandparents than living in a hygienic environment.

Porphylipoprotein Accumulation and Porphylipoprotein Photodynamic Therapy Effects Involving Cancer Cell-Specific Cytotoxicity

In photodynamic therapy (PDT) for neoplasms, photosensitizers selectively accumulate in cancer tissue. Upon excitation with light of an optimal wavelength, the photosensitizer and surrounding molecules generate reactive oxygen species, resulting in cancer cell-specific cytotoxicity. Porphylipoprotein (PLP) has a porphyrin-based nanostructure. The porphyrin moiety of PLP is quenched because of its structure. When PLP is disrupted, the stacked porphyrins are separated into single molecules and act as photosensitizers. Unless PLP is disrupted, there is no photosensitive disorder in normal tissues. PLP can attenuate the photosensitive disorder compared with other photosensitizers and is ideal for use as a photosensitizer. However, the efficacy of PLP has not yet been evaluated. In this study, the mechanism of cancer cell-specific accumulation of PLP and its cytotoxic effect on cholangiocarcinoma cells were evaluated. The effects were investigated on normal and cancer-like mutant cells. The cytotoxicity effect of PLP PDT in cancer cells was significantly stronger than in normal cells. In addition, reactive oxygen species regulated intracellular PLP accumulation. The cytotoxic effects were also investigated using a cholangiocarcinoma cell line. The cytotoxicity of PLP PDT was significantly higher than that of laserphyrin-based PDT, a conventional type of PDT. PLP PDT could also inhibit tumor growth in vivo.

Sodium sulfite causes gastric mucosal cell death by inducing oxidative stress

Sulfites are commonly used as a preservative and antioxidant additives in the food industry. Sulfites are absorbed by the gastrointestinal tract and distributed essentially to all body tissues. Although sulfites have been believed to be safe food additives, some studies have shown that they exhibit adverse effects in various tissues. In this study, we examined the cytotoxic effect of sodium sulfite (Na₂SO₃) against rat gastric mucosal cells (RGM1) and further investigated its underlying molecular mechanism. We demonstrated that exposure to Na₂SO₃ exerts significant cytotoxicity in RGM1 cells through induction of oxidative stress. Exposure of RGM1 cells to Na₂SO₃ caused a significant formation of protein carbonyls and 8-hydroxy-2'-deoxyguanosine, major oxidative stress markers, with a concomitant accumulation of carbonylated protein-related aggregates. Furthermore, we found that incubation of lysozyme with Na₂SO₃ evokes protein carbonylation and aggregation via the metal ion-catalyzed free radical formation derived from Na₂SO₃. Our results suggest that Na₂SO₃ might lead to gastric tissue injury via induction of oxidative stress by the formation of Na₂SO₃-related free radicals.

Comparison of postoperative infection after emergency inguinal hernia surgery with enterectomy between mesh repair and non-mesh repair: a national database analysis

PURPOSE

Synthetic non-absorbable mesh is used for elective inguinal hernia repair but is not commonly used for incarcerated or strangulated inguinal hernia requiring enterectomy to reduce the risk of surgical-site infection. This study aimed to evaluate the safety of synthetic non-absorbable mesh repair in patients with incarcerated or strangulated inguinal hernia requiring enterectomy versus non-mesh repair.

METHODS

We analyzed patients with incarcerated or strangulated inguinal hernia with enterectomy from April 2012 to March 2017 using a nationwide inpatient database in Japan. We conducted overlap propensity score-weighted analyses to compare surgical-site infection (SSI), duration of anesthesia, antibiotic use at > 3 days after surgery, postoperative hospital stay, and 30 day readmission. Two sensitivity analyses were performed. First, we compared the proportions of patients requiring wound culture at ≥ 3 days after surgery. Second, we performed overlap propensity score-weighted logistic regression analyses for surgical-site infection.

RESULTS

We identified 668 eligible patients, comprising 223 patients with mesh repair and 445 with non-mesh repair. Overlap propensity score-weighted analyses showed no significant differences between the mesh repair and non-mesh repair groups for SSI (2.5 vs. 2.8%, P = 0.79). Secondary outcomes did not differ significantly between the groups. Proportion of wound culture at ≥ 3 days after surgery was similar in the two groups (11.1 vs. 14.6%, P = 0.18). Logistic regression analysis showed no significant association between mesh repair and SSI (odds ratio, 0.93; 95% confidence interval, 0.34-2.57).

CONCLUSION

Synthetic non-absorbable mesh use may be safe for incarcerated or strangulated inguinal hernia requiring enterectomy.

Breast cancer surgery in patients with schizophrenia: short-term outcomes from a nationwide cohort

BACKGROUND

Although patients with schizophrenia have a higher risk of developing breast cancer than the general population, studies that have investigated postoperative complications after breast cancer surgery in patients with schizophrenia are scarce. This study examined associations between schizophrenia and short-term outcomes following breast cancer surgery.

METHODS

Patients who underwent surgery for stage 0-III breast cancer between July 2010 and March 2017 were identified from a Japanese nationwide inpatient database. Multivariable analyses were conducted to compare postoperative complications and hospitalization costs between patients with schizophrenia and those without any psychiatric disorder. Three sensitivity analyses were performed: a 1 : 4 matched-pair cohort analysis with matching for age, institution, and fiscal year at admission; analyses excluding patients with schizophrenia who were not taking antipsychotic medication; and analyses excluding patients with schizophrenia who were admitted to hospital involuntarily.

RESULTS

The study included 3660 patients with schizophrenia and 350 860 without any psychiatric disorder. Patients with schizophrenia had a higher in-hospital morbidity (odds ratio (OR) 1.37, 95 per cent c.i. 1.21 to 1.55), with more postoperative bleeding (OR 1.34, 1.05 to 1.71) surgical-site infections (OR 1.22, 1.04 to 1.43), and sepsis (OR 1.20, 1.03 to 1.41). The total cost of hospitalization (coefficient €743, 95 per cent c.i. 680 to 806) was higher than that for patients without any psychiatric disorder. All sensitivity analyses showed similar results to the main analyses.

CONCLUSION

Although causal inferences remain premature, multivariable regression analyses showed that schizophrenia was associated with greater in-hospital morbidity and higher total cost of hospitalization after breast cancer surgery than in the general population.

Free radical degradation in aqueous solution by blowing hydrogen and carbon dioxide nanobubbles

The main findings are the hydroxyl radical scavenging and the superoxide anion diminishing by mixing the carbon dioxide (CO₂) nanobubbles after hydrogen nanobubble blowing in water and alcohol aqueous solution. The nanobubbles produce the hydroxyl radical by ultrasonic waves, changing the pH and catalyst and so on, while the nanobubble is very reactive to scavenge free radicals. In this research especially hydrogen (4% H₂ in argon) and CO₂ nanobubbles have been blown into hydrogen peroxide (H₂O₂) added pure water, ethanol, and ethylene glycol aqueous solution through a porous ceramic sparger from the gas cylinder. The aqueous solutions with H₂O₂ are irradiated by ultraviolet (UV) light and the produced hydroxyl radical amount is measured with spin trapping reagent and electron spin resonance (ESR). The CO₂ nanobubble blowing extremely has reduced the hydroxyl radical in water, ethanol, and ethylene glycol aqueous solution. On the other hand, when H₂ nanobubbles are brown after CO₂ nanobubble blowing, the hydroxyl radical amount has increased. For the disinfection test, the increase of hydroxyl radicals is useful to reduce the bacteria by the observation in the agar medium. Next, when the superoxide anion solution is mixed with nanobubble containing water, ethanol, and ethylene glycol aqueous solution, H₂ nanobubble has reduced the superoxide anion slightly. The water containing both CO₂ and H₂ nanobubble reduces the superoxide anion. The less than 20% ethanol and the 30% ethylene glycol aqueous solution containing CO₂ nanobubbles generated after H₂ nanobubble blowing can diminish the superoxide anion much more. While the H₂ nanobubble blowing after CO₂ nanobubble blowing scavenges the superoxide anion slightly. The experimental results have been considered using a chemical reaction formula.

Elevated Production of Mitochondrial Reactive Oxygen Species via Hyperthermia Enhanced Cytotoxic Effect of Doxorubicin in Human Breast Cancer Cell Lines MDA-MB-453 and MCF-7

Hyperthermia (HT) treatment is a noninvasive cancer therapy, often used with radiation therapy and chemotherapy. Compared with 37 °C, 42 °C is mild heat stress for cells and produces reactive oxygen species (ROS) from mitochondria. To involve subsequent intracellular accumulation of DOX, we have previously reported that the expression of ATP-binding cassette sub-family G member 2 (ABCG2), an exporter of doxorubicin (DOX), was suppressed by a larger amount of intracellular mitochondrial ROS. We then hypothesized that the additive effect of HT and chemotherapy would be induced by the downregulation of ABCG2 expression via intracellular ROS increase. We used human breast cancer cell lines, MCF-7 and MDA-MB-453, incubated at 37 °C or 42 °C for 1 h to clarify this hypothesis. Intracellular ROS production after HT was detected via electron spin resonance (ESR), and DOX cytotoxicity was calculated. Additionally, ABCG2 expression in whole cells was analyzed using Western blotting. We confirmed that the ESR signal peak with HT became higher than that without HT, indicating that the intracellular ROS level was increased by HT. ABCG2 expression was downregulated by HT, and cells were injured after DOX treatment. DOX cytotoxicity enhancement with HT was considered a result of ABCG2 expression downregulation via the increase of ROS production. HT increased intracellular ROS production and downregulated ABCG2 protein expression, leading to cell damage enhancement via DOX.

Mitochondrial reactive oxygen species and heme, non-heme iron metabolism

Mitochondria are one of the most important organelles for eukaryotes, including humans, to produce energy. In the energy-producing process, mitochondria constantly generate reactive oxygen species as a by-product of electrons leaking out from the electron transport chain react with oxygen. The active oxygen, in turn, plays pivotal roles in mediating several signalings, including those that are implicated in the development of some diseases such as neurodegenerative disease, cardiovascular disease, and carcinogenesis. This signaling, derived from mitochondrial reactive oxygen species, also affects intracellular iron homeostasis by regulating the expression of transporters. Heme iron is incorporated into cells through HCP1, and non-heme iron is transported by DMT1 in absorptive cells. Intracellular iron is exported by ferroportin and bound with transferrin. In most types of cell including erythrocyte, transferrin-bound iron is incorporated through transferrin-transferrin receptor system. We previously reported that the expression of HCP1 and DMT1 was upregulated in cancer cells and that overexpression of manganese superoxide dismutase, which is a mitochondrial-specific superoxide dismutase, downregulated the expression. These findings indicate that mitochondrial reactive oxygen species is associated with iron-related oxidative reactions. Recently, a mitochondria-specific iron transporter, mitoferrin, was identified, and the relationships among mitochondria, iron transportation, and diseases have been increasingly clarified.

Age in months and birth order in infant nonfatal injuries: A retrospective cohort study

Objective

To examine the age in months at which infants visited outpatient clinics or emergency rooms for the first time for nonfatal injuries and to identify risk factors for the occurrence of these injuries.

Study design

Retrospective cohort study.

Methods

We used a health insurance claims database in Japan. Infants born between April 2012 and December 2014 were identified and followed until 12 months of age. We identified their first visit to outpatient clinics or emergency rooms because of nonfatal injuries (wounds/fractures, foreign bodies, and burns). Cox regression analysis was used to examine the association of nonfatal injuries with infants’ sex, birth order, and parental age.

Results

We identified 46,431 eligible infants. Of these, 7606 (16.4%) were brought to an outpatient clinic or emergency room for nonfatal injuries within 12 months of birth. Of the 7,606, 21.7% were aged ≤4 months and 44.7% ​≤ ​7 months. First-born infants were more likely to have wounds/fractures and burns.

Conclusion

One-fifth of first nonfatal infant injuries occurred within 4 months of age. Healthcare providers should provide early education about injury prevention, especially to caregivers of first-born infants.

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Nonfatal injuries within first year of birth occurred in 16% of infants.

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22% of first injuries occurred within 4 months of birth.

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First-born infants were more likely to have wounds/fractures and burns.

Rechallenge of voriconazole successfully tolerated after hepatic toxicity

Infections caused by Aspergillus species are often life-threatening. Drugs effective for Aspergillus infection are limited. Voriconazole is one of the most important drugs, however, considerable portion of patients experience liver toxicity and have to stop the drug administration. We frequently experience liver toxicity even though the serum concentration of voriconazole is within the target range. Historically, in some life-threatening situations like tuberculosis, where a suitable alternative is unavailable, rechallenge has been attempted. However, there have been no report on the rechallenge of voriconazole. We report cases of successful re-administration of voriconazole after liver toxicity.

The Risks of Exfoliative Esophagitis in Patients with Atrial Fibrillation: A retrospective observational study

The aging of the population has resulted in atrial fibrillation (AF) becoming increasingly prevalent. Treatment focuses on the prevention of thromboembolism through the use of catheter ablation or drug therapy with anticoagulants, such as warfarin or direct oral anticoagulants (DOACs). Dabigatran-induced exfoliative esophagitis has been reported as a rare side effect of DOACs. Although most cases are mild, some result in severe outcomes. However, the etiology of exfoliative esophagitis remains incompletely understood. The aim of this study is to investigate the etiology of exfoliative esophagitis and identify its risk factors by observational study.The participants were 524 patients using anticoagulants who received catheter ablation for AF and subsequently underwent upper gastrointestinal endoscopy at University of Tsukuba Hospital. Exfoliative esophagitis was noted in 21 (4.0%) patients. Potential risk factors for exfoliative esophagitis were examined retrospectively by comparing patients with and without this condition across the following parameters that were extracted retrospectively from the electronic medical records: physical characteristics, comorbidities, blood-based cardiac markers, echocardiographic and endoscopic findings, and current medications.Regarding physical characteristics, patients with exfoliative esophagitis had significantly higher body weight and BMI. No association was observed between exfoliative esophagitis and comorbidities. Associations were also not found for cardiac markers, echocardiographic findings, or endoscopic findings. In terms of current medications, patients receiving oral dabigatran showed the highest prevalence of exfoliative esophagitis at 8.8% (13/148). The adjusted odds ratio of dabigatran for exfoliative esophagitis was 10.3 by multivariable logistic regression analysis.Obesity and oral dabigatran were found to be significant risk factors for exfoliative esophagitis.

Antioxidant nanomedicine with cytoplasmic distribution in neuronal cells shows superior neurovascular protection properties

This study investigated whether nitroxide radical (4-amino-TEMPOL)-containing nanoparticles (RNPs; antioxidant nanomedicine) can prevent neurovascular unit impairment caused by reactive oxygen species (ROS) after cerebral ischemia-reperfusion. C57BL/6J mice underwent transient middle cerebral artery occlusion (tMCAO). The mice were randomly divided and administered intra-arterial RNPs injection (9 mg/kg, 7 μM/kg), edaravone (3 mg/kg, 17 μM/kg), or phosphate-buffered saline (control group). Survival rate and neurological score were evaluated 24 h post-injection. RNPs distribution was determined using immunofluorescence staining and blood-brain barrier (BBB) disruption using Evans blue extravasation assay. Effect of RNPs and edaravone on microglia polarization into microglia M1 and M2 was evaluated. We also determined multiple ROS-scavenging activities in brain homogenates of RNPs- and edaravone-treated animals using an electron spin resonance-based spin-trapping method. Compared with edaravone, RNPs significantly improved the survival rate and neurological deficit, inhibited BBB disruption and supported polarization of microglia into M2 microglia. RNPs were localized in endothelial cells, the perivascular space, neuronal cell cytoplasm, astrocytes, and microglia. Scavenging capacities of hydroxyl, alkoxyl, and peroxyl radicals were significantly higher in the RNPs-treated group. RNPs show promising results as a future neuroprotective nanomedicine approach for cerebral ischemia-reperfusion injury.

Stent as a bridge to surgery or immediate colectomy for malignant right colonic obstruction: propensity-scored, national database study

Background

The aim of this study was to compare perioperative outcomes of urgent colectomy and placement of a self-expanding metallic stent followed by colectomy for patients with malignant right colonic obstruction. Right-sided malignant obstruction is less common than left-sided. Stenting for malignant left colonic obstruction has been reported to reduce postoperative complications. However, the impact of stenting for malignant right colonic obstruction remains undefined.

Methods

The study included patients with right-sided malignant obstruction or stenosis undergoing colectomy between April 2012 and March 2017 identified from a nationwide database. Propensity score matching analysis was used to compare mortality and morbidity rates, proportion receiving a stoma and postoperative stay between urgent colectomy and stent groups.

Results

From 9572 patients, 1500 pairs were generated by propensity score matching. There was no significant difference in in-hospital mortality between the urgent colostomy and stent groups (1·6 versus 0·9 per cent respectively; P = 0·069). Complications were more common after urgent colectomy than stenting (22·1 versus 19·1 per cent; P = 0·042). Surgical-site infection was more likely with urgent colectomy (7·1 versus 4·4 per cent; P = 0·001). There was no significant difference between the two groups in anastomotic leakage (3·8 versus 2·6 per cent; P = 0·062). The proportion of patients needing a stoma was higher with urgent colectomy than primary treatment with stents (5·1 versus 1·7 per cent; P < 0·001). Postoperative stay was longer after urgent colectomy (15 versus 13 days; P < 0·001).

Conclusion

Stenting followed by colectomy in patients with malignant right colonic obstruction may provide more favourable perioperative outcomes than urgent colectomy.

Evaluation of an amplicon-based custom gene panel for the diagnosis of hereditary tumors

Genetic testing based on next-generation sequencing (NGS) analysis has recently been used to diagnose hereditary diseases. In this study, we explored the usefulness of our custom amplicon panel that targeted 23 genes related to hereditary tumors given in the American College of Medical Genetics and Genomics recommendations. We applied our custom NGS panel to samples from 12 patients previously diagnosed by Sanger sequencing as having the diseases or diagnosed clinically by meeting the diagnostic criteria in this study. Our gene panel not only successfully identified all variants detected by Sanger sequencing but also identified previously unrecognized variants that resulted in confirmation of the disease, or even in the revision of the diagnosis. For instance, a patient identified with an SDHD gene mutation actually had von Hippel-Lindau (VHL) syndrome, as determined by the presence of a pathogenic VHL gene variant. We also identified false-positive results that were generated by amplification of genome regions that are not intended to be investigated. In conclusion, NGS-based amplicon sequencing is a highly effective method to detect germline variants, as long as they are also carefully reviewed by manual inspection.

Liver resection with thrombectomy for patients with hepatocellular carcinoma and tumour thrombus in the inferior vena cava or right atrium

Background

Hepatocellular carcinoma (HCC) with tumour thrombus (TT) in the inferior vena cava (IVC) or right atrium (RA) is a rare advanced disease state with a poor prognosis. The aim of this study was to examine survival after surgical resection.

Methods

Patients with HCC and TT of either the IVC or RA, who underwent liver resection between February 1997 and July 2017, were included. Their short‐ and long‐term outcomes and surgical details were analysed retrospectively.

Results

Thirty‐seven patients were included; 16 patients had TT in the IVC below the diaphragm, eight had TT in the IVC above the diaphragm, and 13 had TT entering the RA. Twelve patients had advanced portal vein TT (portal vein invasion (Vp) greater than Vp3 and Vp4), ten had bilobar disease, and 12 had extrahepatic disease. There were no in‐hospital deaths, although two patients died within 90 days. Median survival did not differ between patients who had resection with curative intent (18·7 months) and those with residual tumour in the lung only (20·7 months), but survival was poor for patients with residual tumour in the liver (8·3 months).

Conclusion

Liver resection with thrombectomy for advanced HCC with TT in the IVC or RA is safe and feasible, leading to moderate survival.

Enhancement of PDT-cytotoxicity via ROS induced by indomethacin in metastatic breast cancer

Breast cancer is one of the most common types of cancers prevalent in women. Several types of breast cancers can easily metastasize to bone and cause disease complications such as hypercalcemia and pathologic fracture, thus compromising the quality of life of people affected by it. Bisphosphonate drugs are often used for the treatment of bone metastasis to suppress osteoclastic bone resorption. However, bisphosphonate has adverse effects on the gastrointestinal tract and kidneys and also induces osteonecrosis of the jaw. Photodynamic therapy (PDT) is an alternative cancer treatment approach with minimal invasiveness. It is a combination treatment that uses photosensitizers, which accumulate in tumor cells, followed by laser irradiation. We previously reported that the cellular incorporation of 5-aminolevulinic acid (5-ALA), which was a precursor of protoporphyrin IX (PpIX), was regulated by reactive oxygen species derived from mitochondria (mitROS). In this study, we investigated the incorporation of 5-ALA, accumulation of PpIX, and subsequent effects on cell viability after laser irradiation of two different breast cancer cell lines with different metastaticites. The highly metastatic breast cancer cell line 4T1E/M3 showed a significant increase in ROS production after treatment with indomethacin (IND). In addition, IND treatment enhanced the cellular uptake of 5-ALA via PEPT1 upregulation in 4T1E/M3, but not in the non-metastatic cell line. Overall, metastatic breast cancer is likely to be sensitive to ROS and activate signaling pathways associated with 5-ALA transportation, suggesting that ALA-PDT could be an effective treatment with low invasiveness for metastatic breast cancer.

Secretory IgA accumulated in the airspaces of idiopathic pulmonary fibrosis and promoted VEGF, TGF-β and IL-8 production by A549 cells

Secretory IgA (SIgA) is a well-known mucosal-surface molecule in first-line defense against extrinsic pathogens and antigens. Its immunomodulatory and pathological roles have also been emphasized, but it is unclear whether it plays a pathological role in lung diseases. In the present study, we aimed to determine the distribution of IgA in idiopathic pulmonary fibrosis (IPF) lungs and whether IgA affects the functions of airway epithelial cells. We performed immunohistochemical analysis of lung sections from patients with IPF and found that mucus accumulated in the airspaces adjacent to the hyperplastic epithelia contained abundant SIgA. This was not true in the lungs of non-IPF subjects. An in-vitro assay revealed that SIgA bound to the surface of A549 cells and significantly promoted production of vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β and interleukin (IL)-8, important cytokines in the pathogenesis of IPF. Among the known receptors for IgA, A549 cells expressed high levels of transferrin receptor (TfR)/CD71. Transfection experiments with siRNA targeted against TfR/CD71 followed by stimulation with SIgA suggested that TfR/CD71 may be at least partially involved in the SIgA-induced cytokine production by A549 cells. These phenomena were specific for SIgA, distinct from IgG. SIgA may modulate the progression of IPF by enhancing synthesis of VEGF, TGF-β and IL-8.

5-Aminolevulinic acid induced apoptosis via oxidative stress in normal gastric epithelial cells

5-Aminolevulinic acid, a precursor of heme, is utilized in a variety of applications including cancer treatment, surgery, and plant nutrition. However, 5-aminolevulinic acid itself induces oxidative stress and subsequent lipid peroxidation. Reactive oxygen species are factors in oxidative stress, not only causing cellular injury but also inducing several signal transduction pathways. Especially in cancer cells, a significant amount of signalling activation and subsequent activation of protein is caused by the enhancement of reactive oxygen species production. Reactive oxygen species levels in normal cells are low and an oxidative condition is harmful; hence, administration of 5-aminolevulinic acid to normal cells may induce oxidative stress, resulting in cell death. In this study, we investigated the effect of 5-aminolevulinic acid on normal and cancer cells with regard to oxidative stress. We used the rat normal gastric cell line RGM and its cancer-like mutant cell line RGK. 5-Aminolevulinic acid treatment of RGM cells enhanced reactive oxygen species generation and induced apoptosis associated with p53, whereas RGK cells were unaffected. In addition, RGM cell viability was recovered by application of N-acetyl-l-cysteine or p53 inhibitor. These results suggest that 5-aminolevulinic acid causes oxidative stress in normal gastric cells and induces apoptosis via the p53-dependent pathway.

Abstract 1285A: Erythropoietin can cancelchemo-resistances viadown regulation of ABC transporters

Introduction: Erythropoietin (EPO) is a glycoprotein cytokine which stimulates red blood cell production (erythropoiesis) in the bone marrow. The receptor of it (EPOR) was reported to exist on the cancer cellular membrane: more than 85% cancer cell expresses EPOR. Several reports suggested to play an important role for cancer cellular growth, however, the role of EPOR in cancer cells is not confirmed. The authors have studied the cancer cellular porphyrin accumulation, metabolism and excretion to clear the pathogenetic mechanism which involved the high concentration of porphyrins. The authors found that reactive oxygen species (ROS) accelerate both the cancer cellular porphyrin accumulation and the effect of photodynamic therapy. However, we cannot confirm which substrate is a key of signal transduction. EPO has been known used to be up-regulated at the metabolic acidosis via the stabilization of HIF-1α, a nuclear factor. Since HIF-1α can be stabilized by not only acidosis but also the high concentration of nitric oxide (NO), NO rich cancer cells may involve EPOR. Moreover, the purpose of EPO-EPOR system is likely to survive the hypoxic condition, it may keep intracellular heme/ porphyrins. The authors’ hypothesis is EPO-EPOR system in cancer cells may down-regulate ABCG2 which excretes heme/ porphyrins, and several anti-cancer drugs. Moreover, if so, the excretion of several anti-cancer chemo reagents should be inhibited to involve more effective chemotherapy.

Methods: To prove these possibilities, the authors carry out following experiments with gastric and colorectal cancer cells. The existence of EPOR, the amount of ABC transporters (B1, C5, G2) after the recombinant EPO (rEPO) exposure (dose dependency and time dependency) were analyzed by western blotting. Cytotoxicity of anti-cancer drugs with or without rEPO was measured with the Cell Counting Kit-8.

Result: (1) EPOR existed in each cell line used in this study. (2) rEPO treatment involved down regulation of ABC transporters (B1, C5, G2) in dose dependently. (3) ABCG2 expression decreased until 24 hours after rEPO treatment. However, its expression re-increased 48 hours after treatment. (4) The 24 hours pretreatment of EPO significantly increased the effect of doxorubicin, paclitaxel, irrinotecan, cisplatin, 5-FU and oxaliplatin even in chemo-resistant cells.

Conclusions: rEPO accelerates the effect of anti-cancer drugs via the down regulation of ABC transporters.

Citation Format: Hirofumi Matsui, Hiromi Kurokawa. Erythropoietin can cancelchemo-resistances viadown regulation of ABC transporters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1285A.

Nationwide observational study of mortality from complicated intra-abdominal infections and the role of bacterial cultures

BACKGROUND

The benefit of taking intra-abdominal cultures during source control procedures in patients with complicated intra-abdominal infection (CIAI) is unknown. The aim of this study was to evaluate whether intra-abdominal cultures reduce the mortality rate of CIAI.

METHODS

The Japanese Diagnosis Procedure Combination database was used to identify adult patients with CIAI who had undergone source control procedures on the first day of admission to hospital between April 2014 and March 2016. In-hospital mortality was compared between patients who did and those who did not have intra-abdominal cultures taken. A generalized linear mixed-effect logistic regression model and a random intercept per hospital were used to adjust for baseline confounders and institutional differences. Subgroup analyses were also performed according to disease cause, site of onset and severity of CIAI.

RESULTS

Intra-abdominal cultures were taken from 16 303 of 41 495 included patients. Multivariable logistic regression analysis showed that patients with intra-abdominal cultures had a significantly lower mortality than those without (odds ratio 0·85, 95 per cent c.i. 0·77 to 0·95). Subgroup analyses revealed statistically significant differences in mortality between patients with and without cultures among those with lower intestinal perforation, biliary tract infection/perforation, healthcare-associated CIAI and high-risk community-acquired CIAI.

CONCLUSIONS

Intra-abdominal cultures obtained during source control procedures may reduce in-hospital mortality, especially in patients with lower intestinal perforation, biliary tract infection/perforation, or healthcare-associated or high-risk community-acquired CIAI.

The preventive effect of Qing Dai on bisphosphonate-induced gastric cellular injuries

The Chinese herbal medicine Qing Dai has been traditionally used for the treatment of various inflammatory diseases. We previously reported that reactive oxygen species play an important role in bisphosphonate-induced gastrointestinal injuries and that Qing Dai improved ulcerative colitis by scavenging reactive oxygen species. In this study, we investigated whether Qing Dai prevented bisphosphonate-induced gastric cellular injuries. Risedronate (a bisphosphonate) was added to rat gastric mucosal cells. Risedronate-induced cellular injury, cellular lipid peroxidation, mitochondrial membrane potential, and reactive oxygen species production in rat gastric mucosal cells were examined via viable cell counting, specific fluorescent indicators, and electron spin resonance. Pretreatment with Qing Dai attenuated the fluorescence intensity of diphenyl-1-pyrenylphosphine and MitoSox as well as the signal intensities of electron spin resonance. Cell viability improved from 20% to 80% by pretreatment with Qing Dai. Thus, Qing Dai prevented this injury by suppressing mitochondrial reactive oxygen species production, which is the main cause of cellular lipid peroxidation. Qing Dai also maintained mitochondrial potential, reducing reactive oxygen species production. We conclude that Qing Dai has protective effects on bisphosphonate-induced gastrointestinal injury and thus has the potential for clinical application.

Secretory immunoglobulin A induces human lung fibroblasts to produce inflammatory cytokines and undergo activation

Immunoglobulin (Ig)A is the most abundant immunoglobulin in humans, and in the airway mucosa secretory IgA (sIgA) plays a pivotal role in first-line defense against invading pathogens and antigens. IgA has been reported to also have pathogenic effects, including possible worsening of the prognosis of idiopathic pulmonary fibrosis (IPF). However, the precise effects of IgA on lung fibroblasts remain unclear, and we aimed to elucidate how IgA activates human lung fibroblasts. We found that sIgA, but not monomeric IgA (mIgA), induced interleukin (IL)-6, IL-8, monocyte chemoattractant protein (MCP)-1 and granulocyte-macrophage colony-stimulating factor (GM-CSF) production by normal human lung fibroblasts (NHLFs) at both the protein and mRNA levels. sIgA also promoted proliferation of NHLFs and collagen gel contraction comparable to with transforming growth factor (TGF)-β, which is involved in fibrogenesis in IPF. Also, Western blot analysis and real-time quantitative polymerase chain reaction (PCR) revealed that sIgA enhanced production of α-smooth muscle actin (α-SMA) and collagen type I (Col I) by NHLFs. Flow cytometry showed that NHLFs bound sIgA, and among the known IgA receptors, NHLFs significantly expressed CD71 (transferrin receptor). Transfection of siRNA targeting CD71 partially but significantly suppressed cytokine production by NHLFs co-cultured with sIgA. Our findings suggest that sIgA may promote human lung inflammation and fibrosis by enhancing production of inflammatory or fibrogenic cytokines as well as extracellular matrix, inducing fibroblast differentiation into myofibroblasts and promoting human lung fibroblast proliferation. sIgA's enhancement of cytokine production may be due partially to its binding to CD71 or the secretory component.

Preoperative oral care and effect on postoperative complications after major cancer surgery

Background

Improving patients' oral hygiene is an option for preventing postoperative pneumonia that may be caused by aspiration of oral and pharyngeal secretions. Whether preoperative oral care by a dentist can decrease postoperative complications remains controversial. A retrospective cohort study was undertaken to assess the association between preoperative oral care and postoperative complications among patients who underwent major cancer surgery.

Methods

The nationwide administrative claims database in Japan was analysed. Patients were identified who underwent resection of head and neck, oesophageal, gastric, colorectal, lung or liver cancer between May 2012 and December 2015. The primary outcomes were postoperative pneumonia and all-cause mortality within 30 days of surgery. Patient background was adjusted for with inverse probability of treatment weighting using propensity scoring.

Results

Of 509 179 patients studied, 81 632 (16·0 per cent) received preoperative oral care from a dentist. A total of 15 724 patients (3·09 per cent) had postoperative pneumonia and 1734 (0·34 per cent) died within 30 days of surgery. After adjustment for potential confounding factors, preoperative oral care by a dentist was significantly associated with a decrease in postoperative pneumonia (3·28 versus 3·76 per cent; risk difference − 0·48 (95 per cent c.i. −0·64 to−0·32) per cent) and all-cause mortality within 30 days of surgery (0·30 versus 0·42 per cent; risk difference − 0·12 (−0·17 to −0·07) per cent).

Conclusion

Preoperative oral care by a dentist significantly reduced postoperative complications in patients who underwent cancer surgery.