Synergistic effect of metformin and vitamin D3 on osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells under high d-glucose conditions.

Introduction: Vitamin D3 plays a vital role in bone health, with low levels of vitamin D3 being related to skeletal fragility, fractures, and metabolic disorders such as diabetes. Metformin is known as an antihyperglycemic agent for regulating blood sugar. A correlation between diabetes mellitus and osteoporosis is attracting considerable interest, and research to find the prevention and treatment is gradually being studied. In this study, we investigated the effect of metformin and vitamin D3 on osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells (AT-MSCs) under high d-glucose concentrations and optimized by combining vitamin D3 and metformin in the process. Methods: ROS production of AT-MSCs under high d-glucose conditions was measured by DCFH-DA assay. The differentiated AT-MSCs were analyzed by Alizarin Red S staining and optical density measurement. The investigation involved the examination of osteogenic master genes' expressions using quantitative reverse transcription polymerase chain reaction (qRT-PCR) techniques. Results: Interestingly, the results have shown that human AT-MSCs will exhibit high ROS accumulation and low osteogenic differentiation capabilities, indicated by low calcium deposition, as well as low expression of indicative genes such as ALP, Runx-2 under high d-glucose conditions. The combination of vitamin D3 and metformin remarkedly accelerated the osteogenic differentiation of AT-MSCs under high d-glucose concentrations more effectively than the administration of either agent. Conclusions: This study partially explains an aspect of an in vitro model for pre-clinical drug screening for osteoporosis-related diabetic pathological mechanisms, which can be applied for further research on the prevention or treatment of osteoporosis in diabetic patients.

Function of Burkholderia pseudomallei RpoS and RpoN2 in bacterial invasion, intracellular survival, and multinucleated giant cell formation in mouse macrophage cell line.

Melioidosis, a human infectious disease with a high mortality rate in many tropical countries, is caused by the pathogen Burkholderia pseudomallei (B. pseudomallei). The function of the B. pseudomallei sigma S (RpoS) transcription factor in survival during the stationary growth phase and conditions of oxidative stress is well documented. Besides the rpoS, bioinformatics analysis of B. pseudomallei genome showed the existence of two rpoN genes, named rpoN1 and rpoN2. In this study, by using the mouse macrophage cell line RAW264.7 as a model of infection, the involvement of B. pseudomallei RpoS and RpoN2 in the invasion, intracellular survival leading to the reduction in multinucleated giant cell (MNGC) formation of RAW264.7 cell line were illustrated. We have demonstrated that the MNGC formation of RAW264.7 cell was dependent on a certain number of intracellular bacteria (at least 5 × 104). In addition, the same MNGC formation (15%) observed in RAW264.7 cells infected with either B. pseudomallei wild type with multiplicity of infection (MOI) 2 or RpoN2 mutant (∆rpoN2) with MOI 10 or RpoS mutant (∆rpoS) with MOI 100. The role of B. pseudomallei RpoS and RpoN2 in the regulation of type III secretion system on bipB-bipC gene expression was also illustrated in this study.

Preparation of self-assembly silica redox nanoparticles to improve drug encapsulation and suppress the adverse effect of doxorubicin.

Background and Purpose: The utilization of doxorubicin (DOX) in clinal trials is also challenging owing to its adverse effects, including low oral bioavailability, generation of reactive oxygen species (ROS), cardiotoxicity, and epithelial barrier damage. Recently, scavenging of ROS reduced the cytotoxicity of DOX, suggesting a new approach for using DOX as an anticancer treatment. Thus, in this study, non-silica and silica redox nanoparticles (denoted as RNPN and siRNP, respectively) with ROS scavenging features have been designed to encapsulate DOX and reduce its cytotoxicity. Experimental Approach: DOX-loaded RNPN (DOX@RNPN) and DOX-loaded siRNP (DOX@siRNP) were prepared by co-dissolving DOX with RNPN and siRNP, respectively. The size and stability of nanoparticles were characterized by the dynamic light scattering system. Additionally, encapsulation efficiency, loading capacity, and release profile of DOX@RNPN and DOX@siRNP were identified by measuring the absorbance of DOX. Finally, the cytotoxicity of DOX@RNPN and DOX@siRNP against normal murine fibroblast cells (L929), human hepatocellular carcinoma cells (HepG2), and human breast cancer cells (MCF-7) were also investigated. Key results: The obtained result showed that RNPN exhibited a pH-sensitive character while silanol moieties improved the stability of siRNP in physiological conditions. DOX@RNPN and DOX@siRNP were formed at several tens of nanometers in diameter with narrow distribution. Moreover, DOX@siRNP stabilized under different pH buffers, especially gastric pH, and improved encapsulation of DOX owing to the addition of silanol groups. DOX@RNPN and DOX@siRNP maintained anticancer activity of DOX against HepG2, and MCF-7 cells, while their cytotoxicity on L929 cells was significantly reduced compared to free DOX treatment. Conclusion: DOX@RNPN and DOX@siRNP could effectively suppress the adverse effect of DOX, suggesting the potential to become promising nanomedicines for cancer treatments.

Sorafenib-loaded silica-containing redox nanoparticles for oral anti-liver fibrosis therapy.

Liver fibrosis is a chronic disease resulting from repetitive or prolonged liver injury with limited treatment options. Sorafenib has been reported to be a potential antifibrotic agent; however, its therapeutic effect is restricted because of its low bioavailability and severe adverse effects in the gastrointestinal (GI) tract. In this study, we developed sorafenib-loaded silica-containing redox nanoparticles (sora@siRNP) as an oral nanomedicine to treat liver fibrosis. The designed siRNP were prepared by self-assembly of amphiphilic block copolymers, which possess antioxidant nitroxide radicals as a side chain of the hydrophobic segment and porous silica particles in the nanoparticle core. The silica moieties in the core formed a crosslink between the self-assembling block copolymers to afford stable drug absorption, which could be useful in harsh GI conditions after oral drug administration. Based on in vitro evaluation, sora@siRNP exerted antiproliferative and antifibrotic effects against hepatic stellate cells (HSCs) and low toxicity against normal endothelial cells. A pharmacokinetic study showed that siRNP significantly improved the bioavailability and distribution of sorafenib in the liver. In an in vivo study using a mouse model of CCl4-induced liver fibrosis, oral administration of sora@siRNP significantly suppressed the fibrotic area in comparison to free sorafenib administration. In mice with CCl4-induced fibrosis, free sorafenib administration did not suppress the expression of α-smooth muscle actin; however, mice treated with sora@siRNP showed significantly suppressed expression of α-smooth muscle actin, indicating the inhibition of HSC activation, which was confirmed by in vitro experiments. Moreover, oral administration of free sorafenib induced severe intestinal damage and increased leakage into the gut, which can be attributed to the generation of reactive oxygen species (ROS). Our antioxidant nanocarriers, siRNP, reduced the adverse effects of local ROS scavenging in the GI tract. Our results suggest that sora@siRNP could serve as a promising oral nanomedicine for liver fibrosis.

A silica-based antioxidant nanoparticle for oral delivery of Camptothecin which reduces intestinal side effects while improving drug efficacy for colon cancer treatment.

Camptothecin (CPT) is a potent anticancer agent for the treatment of colorectal cancer; however, it exhibits some limitations, including poor solubility, low stability, and low bioavailability via oral administration, which restrict its usability in clinical treatments. In addition, overproduction of reactive oxygen species (ROS) during chemotherapy induces drug resistance and severe intestinal side effects. In this study, silica-installed ROS scavenging nanoparticles (siRNP) with 50-60 nm in diameter were employed to overcome the aforementioned drawbacks of CPT. The solubility of CPT was significantly improved by incorporating it into the core of the nanoparticle, forming CPT-loaded siRNP (CPT@siRNP). The anticancer activity of CPT@siRNP against colorectal cancer cells (C-26) in vitro was significantly improved as compared to free CPT through higher efficiency of intracellular internalization and induction of apoptosis. Owing to its antioxidant properties, CPT@siRNP reduced cytotoxicity to normal endothelial cells, which was in sharp contrast to the high toxicity of free CPT. Oral administration of CPT and CPT@siRNP to the C-26 tumor-bearing mice exhibited antitumor activity, accompanied by effective suppression of tumor growth. Although CPT treatment suppressed tumor progression, it caused severe side effects, including intestinal damage and significant bodyweight loss. Interestingly, such noticeable side effects were not observed in the mice treated with CPT@siRNP, and the effect of tumor growth inhibition tended to be similar to or higher than that of CPT treatment. The results obtained in this study indicate that CPT@siRNP is a potential therapeutic nanomedicine for the treatment of colon cancer. STATEMENT OF SIGNIFICANCE: Here we employed silica-containing antioxidant nanoparticle (siRNP) as promising oral delivery nanocarrier of campothecin (CPT) to treat colon cancer. The design of siRNP via covalent conjugation of antioxidant nitroxide radicals and the silanol groups in the polymer backbone contributes to a significant increase in the absorption of hydrophobic drug molecules inside the core and enhances the stability of nanoparticles in the gastrointestinal environment for oral drug delivery. CPT-loaded siRNP (CPT@siRNP) significantly improved solubility of CPT. As compared to free CTP, the CPT@siRNP treatment showed a significantly higher toxicity to colon cancer cell, inhibition of cancer cell migration, and induction of apopotosis. With the antioxidant feature, siRNP also significantly suppressed the intestinal side effects caused by CPT treatment in tumor-bearing mouse model.

Tailoring chemical compositions of biodegradable mesoporous organosilica nanoparticles for controlled slow release of chemotherapeutic drug.

Biodegradable periodic mesoporous organosilica nanoparticles (B-PMO) are an outstanding nanocarrier due to their biodegradability and high drug load capacities. The present study describes a synthesis of a phenylene-containing tetrasulfide based B-PMO, named P4S. The incorporation of aromatic phenylene groups into the framework creates a strong interaction between nanoparticles (NPs) with aromatic rings in the cordycepin molecules. This results in the low release profile under various conditions. In addition, the replacement of this linker slowed the degradation of nanoparticles. The physicochemical properties of the nanoparticles are evaluated and compared with a biodegradable ethane-containing tetrasulfide based PMO and a non-degradable MCM-41. The biodegradability of P4S is also demonstrated in a reducing environment and the 100 nm spherical nanoparticles completely decomposed within 14 days. The porous structure of P4S has a high loading of hydrophilic cordycepin (approximately 731.52 mg g-1) with a slow releasing speed. The release rates of P4S NPs are significantly lower than other materials, such as liposomes, gelatin nanoparticles, and photo-crosslinked hyaluronic acid methacrylate hydrogels, in the same solution. This specific release behavior could guarantee drug therapeutic effects with minimum side-effects and optimized drug dosages. Most importantly, according to the in vitro cytotoxicity study, cordycepin-loaded P4S NPs could retain the toxicity against liver cancer cell (HepG2) while suppressed the cytotoxicity against normal cells (BAEC).

Improving silymarin oral bioavailability using silica-installed redox nanoparticle to suppress inflammatory bowel disease.

Chronic inflammatory diseases such as inflammatory bowel diseases (IBD), which are strongly related to the overproduction of reactive oxygen species (ROS), have become more threatening to health. Silymarin is an active compound with the effect of expressing anti-inflammatory activity; however, it exhibits poor bioavailability due to the rapid metabolism and secretion, low permeability across the intestinal epithelial cells, and poor water solubility. In this study, we developed silica-containing redox nanoparticles (siRNP) with 50-60 nm in diameter to improve the bioavailability of silymarin by improving its uptake into the bloodstream and delivery to the targeted tissues of the colon. Silymarin-loaded siRNP (SM@siRNP) significantly increased the antioxidant capacity and anti-inflammatory efficacy in vitro by scavenging 2,2-diphenyl-1-picrylhydrazyl free radical and suppressing nitric oxide and pro-inflammatory cytokines as compared to the other treatments such as free silymarin, siRNP, and silymarin-loaded si-nRNP (the control nanoparticle without ROS scavenging property). Orally administered SM@siRNP significantly improved the bioavailability of silymarin and its retention in the colonic mucosa. The anti-inflammatory effects of SM@siRNP were also investigated in dextran sodium sulfate (DSS)-induced colitis in mice and it was observed that SM@siRNP treatment significantly improved the damage in the colonic mucosa of DSS colitis mice as compared to the other treatments. The results in this study indicate that SM@siRNP is a promising nanomedicine for enhancing the anti-inflammatory activity of silymarin and has a high potential for the treatment of IBD.

Nitric Oxide Nano-Delivery Systems for Cancer Therapeutics: Advances and Challenges.

Nitric oxide (NO) plays important roles in various physiological and pathological functions and processes in the human body. Therapeutic application of NO molecules has been investigated in various diseases, including cardiovascular disease, cancer, and infections. However, the extremely short half-life of NO, which limits its clinical use considerably, along with non-specific distribution, has resulted in a low therapeutic index and undesired adverse effects. To overcome the drawbacks of using this gaseous signaling molecule, researchers in the last several decades have focused on innovative medical technologies, specifically nanoparticle-based drug delivery systems (DDSs), because these systems alter the biodistribution of the therapeutic agent through controlled release at the target tissues, resulting in a significant therapeutic drug effect. Thus, the application of nano-systems for NO delivery in the field of biomedicine, particularly in the development of new drugs for cancer treatment, has been increasing worldwide. In this review, we discuss NO delivery nanoparticle systems, with the aim of improving drug delivery development for conventional chemotherapies and controlling multidrug resistance in cancer treatments.

Design of amino acid-based self-assembled nano-drugs for therapeutic applications.

Amino acids have attracted considerable attention in drug development because they play important roles in many physiological and pathological processes. In the past several decades, various amino acid supplementations have been reported to have potential therapeutic efficacy for the treatment of many disorders in clinical trials. However, their effectiveness is controversially reported, which may be explained by poor pharmacokinetic properties of such low-molecular-weight agents. Amino acid-based self-assembled macromolecules could overcome the aforementioned drawbacks by improving the pharmacokinetic profile and accumulation of specific molecules at target sites to enhance the therapeutic effect. In this review, we have discussed the current therapeutic applications of certain amino acids, and have introduced our approach of using amino acid-based self-assembled nanostructures as novel therapeutic agents.

Self-assembled polydopamine nanoparticles improve treatment in Parkinson's disease model mice and suppress dopamine-induced dyskinesia.

Although Levodopa (l-DOPA), a dopamine precursor, exhibits a high risk of dyskinesia, it remains the primary treatment in Parkinson's disease (PD), a progressive neurodegenerative disorder. In this study, we designed poly(l-DOPA)-based self-assembled nanodrug (NanoDOPA) from amphiphilic block copolymer possessing poly(l-DOPA(OAc)2), which is a precursor of l-DOPA as a hydrophobic segment, for treatment in a PD model mouse. Under physiological enzyme treatment, the poly(l-DOPA(OAc)2) in the block copolymer was hydrolyzed to liberate l-DOPA gradually. Using the MPTP-induced PD mouse model, we observed that mice treated with NanoDOPA demonstrated a significant improvement of PD symptoms compared to the l-DOPA treatment. Interestingly, the NanoDOPA treatment did not cause the dyskinesia symptoms, which was clearly observed in the l-DOPA-treated mice. Furthermore, NanoDOPA exhibited remarkably lower toxicity in vitro compared to l-DOPA, in addition with no noticeable NanoDOPA toxicity observed in the treated mice. These results suggested that self-assembled NanoDOPA is a promising therapeutic in the treatment of PD. STATEMENT OF SIGNIFICANCE: In this study, we proposed a therapeutic approach for the effective treatment of Parkinson's disease (PD) using newly designed poly(l-DOPA)-based self-assembled nanodrug (NanoDOPA) prepared from amphiphilic block copolymers possessing poly(l-DOPA(OAc)2), which is a precursor of l-DOPA as a hydrophobic segment, for treatment in a PD model mouse. Under physiological enzyme treatments, NanoDOPA was hydrolyzed to liberate l-DOPA gradually, improving the pharmacokinetic value of l-DOPA. The mice treated with NanoDOPA significantly improved PD symptoms compared to the l-DOPA treatment in a neurotoxin-induced PD mouse model. Interestingly, NanoDOPA treatment did not cause dyskinesia symptoms, which was observed in the l-DOPA-treated mice. The obtained results in this study suggested that self-assembled NanoDOPA is a promising therapeutic in the treatment of PD.

Encapsulation of tissue plasminogen activator in pH-sensitive self-assembled antioxidant nanoparticles for ischemic stroke treatment - Synergistic effect of thrombolysis and antioxidant.

The medical treatment for stroke has advanced greatly in recent years. Thrombolytic therapy with tissue plasminogen activator (t-PA) is one of the mainstream treatments, but it still has many problems, including short half-life, and t-PA-induced reperfusion and oxidative injuries. To broaden the therapeutic window of t-PA and reduce its associated oxidative stress after reperfusion, t-PA-installed, nitroxide radical-containing, self-assembled polyion complex nanoparticles (t-PA@iRNP) were designed. Encapsulation of t-PA in the self-assembled antioxidant nanoparticles improved its bioavailability and extended its therapeutic window. To suppress reactive oxygen species (ROS) in the ischemic penumbra area, the low-molecular-weight nitroxide antioxidant 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl was covalently conjugated with the nanoparticle matrix, thus suppressing oxidative damage in the brain after reperfusion. t-PA and nitroxide radicals were confined and protected in the core of t-PA@iRNP, thereby preventing their rapid metabolism and excretion out of the body after systemic circulation for prolonged period. The nano-sized formulation prevented non-specific internalization of t-PA@iRNP in healthy cells, thereby preserving the normal function of redox reactions in the cells, especially important redox reactions such as electron transport chains. This improved pharmacological performance of t-PA@iRNP remarkably extended the in vivo half-life of t-PA in systemic circulation. Using a mouse model of photo-thrombotic middle cerebral artery occlusion, we found that t-PA@iRNP treatment, compared with naked t-PA, void iRNP, or t-PA@niRNP (non-ROS scavenging nanoparticle as a control), significantly suppressed increases in cerebral infarct volume and improved neurological deficit after brain ischemia. t-PA-induced subarachnoid hemorrhage was also suppressed by t-PA@iRNP treatment through elimination of overproduced ROS. Based on these data, t-PA@iRNP presents therapeutic potential through synergistic effect of thrombolysis and antioxidant effects for preventing and treating ischemia-reperfusion injury.

Novel angiogenesis therapeutics by redox injectable hydrogel - Regulation of local nitric oxide generation for effective cardiovascular therapy.

Nitric oxide (NO) possesses various functions in cardiovascular diseases; however, due to an extremely short half-life and low bioavailability, its therapeutic application is limited. In inflamed tissues, overproduced reactive oxygen species (ROS) rapidly react with the endogenous NO, reducing its bioavailability. Here, we developed a controllable NO-releasing redox injectable hydrogel (NO-RIG) formed by the electrostatic crosslinking between the polyion complex flower-type micelles composing of functional polymers to scavenge overproduced ROS and regulate the local NO expression level simultaneously. After the intracardiac injection to mice, NO-RIG converted to gel via physiological temperature-responsive character, distributed homogeneously, and retained in the myocardial tissue for more than 10 d. Treatment with NO-RIG remarkably decreased the infarction size and improved the heart function after myocardial infarction when compared to control injectable hydrogels, such as a simple NO-releasing or ROS-scavenging injectable gels. We found that NO-RIG treatment significantly enhanced the angiogenesis and new blood vessels formation in mice through the regulation of the NO sustained release and redox equilibrium. NO-RIG presents high potential in preventing and treating cardiovascular diseases.

Newly Designed Silica-Containing Redox Nanoparticles for Oral Delivery of Novel TOP2 Catalytic Inhibitor for Treating Colon Cancer.

Although oral drug delivery is the most common route of drug administration, the conventional polymeric nanocarriers exhibit a low drug loading capacity and low stability in the gastrointestinal (GI) environments. In this study, a newly designed silica-containing redox nanoparticle (siRNP) with reactive oxygen species (ROS) scavenging capacity is developed as an ideal oral nanocarrier for a novel hydrophobic anticancer compound BNS-22 to treat colitis-associated colon cancer in vivo. Crosslinking of silica moieties significantly enhances the stability under acidic conditions and improves BNS-22 loading capacity of siRNP compared to the conventional redox nanoparticle. After oral administration to mice, BNS-22-loaded siRNP (BNS-22@siRNP) remarkably improves bioavailability and colonic tumor distribution of BNS-22. As the result, BNS-22@siRNP significantly inhibits the tumor progression in colitis-associated colon cancer mice compared to other control treatments. It is noteworthy that no systemic absorption of siRNP carrier is observed after oral administration. Interestingly, orally administered BNS-22@siRNP significantly suppresses the adverse effects of BNS-22 owing to its ROS scavenging capacity, and no other noticeable toxicities are observed in mice treated with BNS-22@siRNP although siRNP is localized in the GI tract. Our results indicate that siRNP is a promising oral drug nanocarrier for cancer therapy.

Chronic treatment with a smart antioxidative nanoparticle for inhibition of amyloid plaque propagation in Tg2576 mouse model of Alzheimer's disease.

The present study aimed to assess whether our newly developed redox nanoparticle (RNPN) that has antioxidant potential decreases Aß levels or prevents Aß aggregation associated with oxidative stress. The transgenic Tg2576 Alzheimer's disease (AD) mice were used to investigate the effect of chronic ad libitum drinking of RNPN solution for 6 months, including memory and learning functions, antioxidant activity, and amyloid plaque aggregation. The results showed that RNPN-treated mice had significantly attenuated cognitive deficits of both spatial and non-spatial memories, reduced oxidative stress of lipid peroxide, and DNA oxidation. RNPN treatment increased the percent inhibition of superoxide anion and glutathione peroxidase activity, neuronal densities in the cortex and hippocampus, decreased Aß(1-40), Aß(1-42) and gamma (γ)-secretase levels, and reduced Aß plaque observed using immunohistochemistry analysis and thioflavin S staining. Our results suggest that RNPN may be a promising candidate for AD therapy because of its antioxidant properties and reduction in Aß aggregation, thereby suppressing its adverse side effect.

Evaluation of the Toxicity and Antioxidant Activity of Redox Nanoparticles in Zebrafish (Danio rerio) Embryos.

Recently, we have been developing polymer and nanoparticle-based antioxidative nanotherapeutics. Our strategy is to eliminate overproduced reactive oxygen species (ROS), which are strongly related to various diseases. In order to facilitate the transition of the nanotherapeutics into clinical studies, we investigated the toxicity and antioxidant activity of our nanoparticles in a zebrafish model. In this study, zebrafish larvae were exposed to our highly ROS-scavenging nanoparticle (RNP(O)), which was prepared using our original amphiphilic block copolymer, methoxy-poly(ethylene glycol)-b-poly[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)oxymethylstyrene] (MeO-PEG-b-PMOT). When the larvae were exposed to 10-30 mM of low-molecular-weight (LMW) nitroxide radical (4-hydroxyl-2,2,6,6-tetramethylpiperidine-1-oxyl; TEMPOL), all were dead after 12 h, whereas no larva death was observed after exposure to RNP(O) at the same high concentrations. By staining mitochondria from the larvae, we found that LMW TEMPOL significantly induced mitochondrial dysfunction. In contrast, RNP(O) did not cause any significant reduction in the mitochondrial function of zebrafish larvae. It is important to reaffirm that RNP(O) treatment significantly enhanced survival of larvae treated with ROS inducers, confirming the antioxidant activity of RNP(O). Interestingly, RNP(O) exposure induced the expression of Nrf2 target gene (gstp1) in the larvae's intestines and livers. The results obtained in this study indicate that the antioxidative nanoparticle RNP(O) has great potential for clinical trials as it exhibits a potent therapeutic effect and extremely low toxicity to zebrafish embryos.

Combination Treatment of Murine Colon Cancer with Doxorubicin and Redox Nanoparticles.

Conventional chemotherapeutic drugs such as doxorubicin (DOX) are associated with severe adverse effects such as cardiac, hepatic, and gastrointestinal (GI) toxicities. Excessive production of reactive oxygen species (ROS) was reported to be one of the main mechanisms underlying these severe adverse effects. Recently, we have developed 2 types of novel redox nanoparticles (RNPs) including pH-sensitive redox nanoparticle (RNP(N)) and pH-insensitive redox nanoparticle (RNP(O)), which effectively scavenge overproduced ROS in inflamed and cancerous tissues. In this study, we investigated the effects of these RNPs on DOX-induced adverse effects during cancer chemotherapy. The DOX-induced body weight loss was significantly attenuated in the mice treated with RNPs, particularly pH-insensitive RNP(O). We also found that cardiac ROS levels in the DOX-treated mice were dramatically decreased by treatment with RNPs, resulting in the reversal of cardiac damage, as confirmed by both plasma cardiac biomarkers and histological analysis. It was interesting to notice that, during cotreatment with DOX and RNPs, the DOX uptake was significantly enhanced in the cancer cells, but not in healthy aortic endothelial cells in vitro. Treatment with RNPs also improved anticancer efficacy of DOX in the colitis-associated colon cancer model mice in vivo. On the basis of these results, a combination of the novel antioxidative nanotherapeutics (RNPs) with conventional anticancer drugs seems to be a robust strategy for well-tolerated anticancer therapy.

Specific accumulation of orally administered redox nanotherapeutics in the inflamed colon reducing inflammation with dose-response efficacy.

Although current medications for ulcerative colitis (UC) are effective to some extent, there are still some limitation of their use due to the non-specific distribution, drug metabolism in the gastrointestinal tract, and severe adverse effects. In our previous studies, we developed oral redox nanoparticles (RNP(O)) that specifically accumulated and scavenged overproduced reactive oxygen species (ROS) in an inflamed colon. However, the mechanism leading to specific accumulation of RNP(O) in an inflamed colon is still unclear. In this study, we investigated the cellular uptake of RNP(O) into ROS-treated epithelial colonic cells in vitro, and compared to the untreated cells, found a significantly increased uptake in ROS-treated cells. In vivo, we discovered that orally administered RNP(O) were not internalized into the cells of a normal colon. A significant amount of disintegrated RNP(O) was detected in the cells of an inflamed colon of dextran sodium sulfate (DSS)-induced colitis mice, resulting in scavenging of ROS and suppression of inflammation with low adverse effects. Furthermore, we confirmed a significant reduction of disease activity and a robust dose response efficacy following RNP(O) treatment in acute DSS-induced colitis mice, outperforming the positive control 5-aminosalicylic acid. Oral administration of RNP(O) is a promising approach to develop a new therapy for UC disease.

Redox nanoparticles as a novel treatment approach for inflammation and fibrosis associated with nonalcoholic steatohepatitis.

AIM: Oxidative stress (OS) is largely thought to be a central mechanism responsible for liver damage, inflammation and fibrosis in nonalcoholic steatohepatitis (NASH). Our aim was to investigate whether suppression of OS in the liver via redox nanoparticles (RNPs) reduces liver damage in a mouse model of NASH. MATERIALS & METHODS: RNPs were prepared by self-assembly of redox polymers possessing antioxidant nitroxide radicals and were orally administered by daily gavage for 4 weeks. RESULTS: The redox polymer was delivered to the liver after disintegration of nanoparticle in the stomach. RNP treatment in NASH mice via gavage led to a reduction of liver OS, improvement of fibrosis, and significant reduction of inflammation. CONCLUSION: These findings uncover RNP as a novel potential NASH therapy.

Recovery of Cognitive Dysfunction via Orally Administered Redox-Polymer Nanotherapeutics in SAMP8 Mice.

Excessively generated reactive oxygen species are associated with age-related neurodegenerative diseases. We investigated whether scavenging of reactive oxygen species in the brain by orally administered redox nanoparticles, prepared by self-assembly of redox polymers possessing antioxidant nitroxide radicals, facilitates the recovery of cognition in 17-week-old senescence-accelerated prone (SAMP8) mice. The redox polymer was delivered to the brain after oral administration of redox nanoparticles via a disintegration of the nanoparticles in the stomach and absorption of the redox polymer at small intestine to the blood. After treatment for one month, levels of oxidative stress in the brain of SAMP8 mice were remarkably reduced by treatment with redox nanoparticles, compared to that observed with low-molecular-weight nitroxide radicals, resulting in the amelioration of cognitive impairment with increased numbers of surviving neurons. Additionally, treatment by redox nanoparticles did not show any detectable toxicity. These findings indicate the potential of redox polymer nanotherapeutics for treatment of the neurodegenerative diseases.

Development of an oral nanotherapeutics using redox nanoparticles for treatment of colitis-associated colon cancer.

Oral chemotherapy is the preferred treatment for colon cancer. However, this strategy faces many challenges, including instability in the gastrointestinal (GI) tract, insufficient bioavailability, low tumor targeting, and severe adverse effects. In this study, we designed a novel redox nanoparticle (RNP(O)) that is an ideal oral therapeutics for colitis-associated colon cancer treatment. RNP(O) possesses nitroxide radicals in the core, which act as reactive oxygen species (ROS) scavengers. Orally administered RNP(O) highly accumulated in colonic mucosa, and specifically internalized in cancer tissues, but less in normal tissues. Despite of long-term oral administration of RNP(O), no noticeable toxicities were observed in major organs of mice. Because RNP(O) effectively scavenged ROS, it significantly suppressed tumor growth after accumulation at tumor sites. Combination of RNP(O) with the conventional chemotherapy, irinotecan, led to remarkably improved therapeutic efficacy and effectively suppressed its adverse effects on GI tract. Therefore, RNP(O) is promising oral nanotherapeutics for cancer therapies.