Nanogap-containing thermo-plasmonic nano-heaters for amplified photo-triggered tumor ablation at low laser power density.

Herein, nanogap amplified plasmonic heat-generators are fabricated by decorating Pt nanodots on gold nanospheres (GNSs@Pt@mPEG) by maintaining strategic nano-gaps (1-2 nm) and studied precisely for plasmonic photothermal therapy (PPTT) of colon cancer by passive tumor targeting. The surface modification of GNSs@Pt with poly(ethylene glycol) methyl ether thiol (mPEG) increases their accumulation in tumor cells and hence the GNSs@Pt@mPEG stay at the tumor site for a longer time. The nanogap amplified GNSs@Pt@mPEG (O.D. = 4.0) generated high plasmonic photothermal hyperthermia and utilized a low NIR power density (0.36 W cm-2) for the elimination of tumor cells in only 150 s of irradiation time and shows excellent colloidal and photo-stability. The predominant distribution of GNSs@Pt@mPEG caused effective tumor cell death and promoted uniform treatment on tumor sites. In vivo studies demonstrated that the GNSs@Pt@mPEG have very low toxicity, high biocompatibility, and thermal stability, stay longer at the tumor site, induce tumor cell death without side effects, and show significantly less uptake in other organs except for the spleen. The significant accumulations and longer stay suggested that they are favorable for tumor passive uptake and the possibility of enhanced PPTT after intravenous administration. The nano-particles were stable up to O.D. 200 and have at least 12 months shelf-life without losing colloidal stability or photothermal efficacy. These findings lay the groundwork for using GNSs@Pt@mPEG as a NIR light-responsive PPTT agent and demonstrated their potential for further use in clinical applications.

Intravitreal Injection of Liposomes Loaded with a Histone Deacetylase Inhibitor Promotes Retinal Ganglion Cell Survival in a Mouse Model of Optic Nerve Crush.

Various neuroprotective agents have been studied for the treatment of retinal ganglion cell (RGC) diseases, but issues concerning the side effects of systemically administered drugs and the short retention time of intravitreally injected drugs limit their clinical applications. The current study aimed to evaluate the neuroprotective effects of intravitreally injected trichostatin A (TSA)-loaded liposomes in a mouse model of optic nerve crush (ONC) and determine whether TSA-loaded liposomes have therapeutic potential in RGC diseases. The histone deacetylase inhibitor, TSA, was incorporated into polyethylene glycolylated liposomes. C57BL/6J mice were treated with an intravitreal injection of TSA-loaded liposomes and liposomes loaded with a lipophilic fluorescent dye for tracking, immediately after ONC injury. The expression of macroglial and microglial cell markers (glial fibrillary acidic protein and ionized calcium binding adaptor molecule-1), RGC survival, and apoptosis were assessed. We found that the liposomes reached the inner retina. Their fluorescence was detected for up to 10 days after the intravitreal injection, with peak intensity at 3 days postinjection. Intravitreally administered TSA-loaded liposomes significantly decreased reactive gliosis and RGC apoptosis and increased RGC survival in a mouse model of ONC. Our results suggest that TSA-loaded liposomes may help in the treatment of various RGC diseases.

Combination of Photodynamic Therapy and a Flagellin-Adjuvanted Cancer Vaccine Potentiated the Anti-PD-1-Mediated Melanoma Suppression.

Immune checkpoint inhibitors become a standard therapy for malignant melanoma. As immune checkpoint inhibitor monotherapies proved to have limited efficacy in significant portion of patients, it is envisaged that combination with other therapeutic modalities may improve clinical outcomes. We investigated the effect of combining photodynamic therapy (PDT) and TLR5 agonist flagellin-adjuvanted tumor-specific peptide vaccination (FlaB-Vax) on the promotion of PD-1 blockade-mediated melanoma suppression using a mouse B16-F10 implantation model. Using a bilateral mouse melanoma cancer model, we evaluated the potentiation of PD-1 blockade by the combination of peritumoral FlaB-Vax delivery and PDT tumor ablation. A photosensitizing agent, pheophorbide A (PhA), was used for laser-triggered photodynamic destruction of the primary tumor. The effect of combination therapy in conjunction with PD-1 blockade was evaluated for tumor growth and survival. The effector cytokines that promote the activation of CD8+ T cells and antigen-presenting cells in tumor tissue and tumor-draining lymph nodes (TDLNs) were also assayed. PDT and FlaB-Vax combination therapy induced efficacious systemic antitumor immune responses for local and abscopal tumor control, with a significant increase in tumor-infiltrating effector memory CD8+ T cells and systemic IFNγ secretion. The combination of PDT and FlaB-Vax also enhanced the infiltration of tumor antigen-reactive CD8+ T cells and the accumulation of migratory CXCL10-secreting CD103+ dendritic cells (DCs) presumably contributing to tumor antigen cross-presentation in the tumor microenvironment (TME). The CD8+ T-cell-dependent therapeutic benefits of PDT combined with FlaB-Vax was significantly enhanced by a PD-1-targeting checkpoint inhibitor therapy. Conclusively, the combination of FlaB-Vax with PDT-mediated tumor ablation would serve a safe and feasible combinatorial therapy for enhancing PD-1 blockade treatment of malignant melanoma.

A bilirubin-conjugated chitosan nanotheranostics system as a platform for reactive oxygen species stimuli-responsive hepatic fibrosis therapy.

The development of nanoparticles that can be used as stimuli-responsive drug carriers for the treatment of different diseases has been an emerging area of research. In this study, we designed a chitosan-bilirubin micelle (ChiBil) carrying losartan, which is responsive to intrinsic reactive oxygen species (ROS), for the treatment of hepatic fibrosis. Because bilirubin is hydrophobic in nature, its carboxyl group was conjugated to an amine group from chitosan using EDC-NHS chemistry to form an amphiphilic conjugate, ChiBil. Losartan is an angiotensin receptor blocker that reduces hepatic fibrosis, and it was used as the therapeutic payload in this study to form ChiBil-losartan micelles. The release characteristics of ChiBil-losartan were tested by ROS generation to confirm losartan release. Human hepatic stellate cell line LX2 was found to be the best in vitro model for the study. The reduction of hepatic stellate cell activation after treatment with ChiBil-losartan was analyzed based on the expression of alpha-smooth muscle actin (α-SMA) in both in vitro and in vivo studies. Advanced liver fibrosis was induced in C3H/HeN mice using a thioacetamide (TAA) via intraperitoneal injection and 10% ethanol (EtOH) in their drinking water. In addition, the hydroxyproline levels, histopathological evaluation, and mRNA quantification in the liver showed a decreased collagen content in the treated groups compared to that in the untreated control group. Macrophage infiltration studies and qPCR studies of inflammatory markers also proved the reduction of hepatic fibrosis in the treatment group. The intravenous administration of ChiBil-losartan resulted in decreased fibrosis in a TAA/EtOH-induced liver fibrosis mouse model. The in vitro and in vivo results suggest that the ROS stimuli-responsive ChiBil nanoparticles carrying losartan may be a potent therapeutic option for the treatment of hepatic fibrosis. The combined effect of losartan and bilirubin exhibited a decreased hepatic fibrosis both in vitro and in vivo.

Glycol chitosan-based renal docking biopolymeric nanomicelles for site-specific delivery of the immunosuppressant.

In this study, we propose the use of glycol chitosan for the targeted delivery of hydrophobic drugs such as tacrolimus (TAC) towards the kidney. We synthesized a hydrophobically modified glycol chitosan (HGC) polymeric nanomicelle followed by loading TAC resulting in TAC loaded HGC nanomicelles (HGC-TAC). The HGC-TAC nanomicelles displayed spherical morphology with superior drug loading content and encapsulation efficiency. in vitro and in vivo evaluations demonstrated that HGC-TAC nanomicelles are non toxic and delivered TAC preferentially to kidney while lowering the plasma concentrations. The therapeutic effects of HGC-TAC and unencapsulated ("bare") TAC on the kidneys showed that a single intravenous administration of HGC-TAC achieved a therapeutic efficacy comparable to that obtained from daily intraperitoneal injections of TAC for 14 days without any systemic side effects. Thus, HGC-TAC nanomicelles could be effectively used for delivery of TAC towards the kidney, highlighting its potential as a safe modality for renal-targeted delivery of therapeutics.

Effect of hepato-toxins in the acceleration of hepatic fibrosis in hepatitis B mice.

Chronic liver diseases such as hepatitis B viral (HBV) infection and liver fibrosis have been a major health problem worldwide. However, less research has been conducted owing to the lack of animal models. The key purpose of this study was to determine the effects of different hepatotoxins in HBV-affected liver. In this study, we successfully generated a combined liver fibrosis model by administering HBV 1.2 plasmid and thioacetamide/ethanol (TAA/EtOH). To our knowledge, this is the first study in which an increase in the liver fibrosis level is observed by the intraperitoneal administration of TAA and EtOH in drinking water after the hydrodynamic transfection of the HBV 1.2 plasmid in C3H/HeN mice. The HBV+TAA/EtOH group exhibited higher level of hepatic fibrosis than that of the control groups. The hepatic stellate cell activation in the TAA- and EtOH-administered groups was demonstrated by the elevation in the level of fibrotic markers. In addition, high levels of collagen content and histopathological results were also used to confirm the prominent fibrotic levels. We established a novel HBV mice model by hydrodynamic injection-based HBV transfection in C3H/HeN mice. C3H/HeN mice were reported to have a higher HBV persistence level than that of the C57BL/6 mouse model. All the results showed an increased fibrosis level in the HBV mice treated with TAA and EtOH; hence, this model would be useful to understand the effect of hepatotoxins on the high risk of fibrosis after HBV infection. The acceleration of liver fibrosis can occur with prolonged administration as well as the high dosage of hepatotoxins in mice.

Biomedical Applications of Hyaluronic Acid-Based Nanomaterials in Hyperthermic Cancer Therapy.

Hyaluronic acid (HA) is a non-sulfated polysaccharide polymer with the properties of biodegradability, biocompatibility, and non-toxicity. Additionally, HA specifically binds to certain receptors that are over-expressed in cancer cells. To maximize the effect of drug delivery and cancer treatment, diverse types of nanomaterials have been developed. HA-based nanomaterials, including micelles, polymersomes, hydrogels, and nanoparticles, play a critical role in efficient drug delivery and cancer treatment. Hyperthermic cancer treatment using HA-based nanomaterials has attracted attention as an efficient cancer treatment approach. In this paper, the biomedical applications of HA-based nanomaterials in hyperthermic cancer treatment and combined therapies are summarized. HA-based nanomaterials may become a representative platform in hyperthermic cancer treatment.

Metabolic Changes in Different Stages of Liver Fibrosis: In vivo Hyperpolarized 13C MR Spectroscopy and Metabolic Imaging.

PURPOSE: The objective was to assess metabolic changes in different stages of liver fibrosis using hyperpolarized C-13 magnetic resonance spectroscopy (MRS) and metabolic imaging. PROCEDURES: Mild and severe liver fibrosis were induced in C3H/HeN mice (n = 14) by injecting thioacetamide (TAA). Other C3H/HeN mice (n = 7) were injected with phosphate buffer saline (PBS) (7.4 pH) as normal controls. Hyperpolarized C-13 MRS was performed on the livers of the mice, which was accompanied by intravoxel incoherent motion (IVIM) diffusion-weighted imaging with 12 b values. The differential metabolite ratios, apparent diffusion coefficient values, and IVIM parameters among the three groups were analyzed by a one-way analysis of variance test. RESULTS: The ratios of [1-13C]lactate/pyruvate, [1-13C]lactate/total carbon (tC), [1-13C]alanine/pyruvate, and [1-13C] alanine/tC were significantly higher in both the mild and severe fibrosis groups than in the normal control group (p < 0.05). While the [1-13C]lactate/pyruvate and [1-13C]lactate/tC ratios were not significantly different between mild and severe fibrosis groups, the ratios of [1-13C]alanine/pyruvate and [1-13C]alanine/tC were significantly higher in the severe fibrosis group than in the mild fibrosis group (p < 0.05). In addition, D* showed a significantly lower value in the severe fibrosis group than in the normal or mild fibrosis groups and negatively correlated with the levels of [1-13C] lactate and [1-13C]alanine. CONCLUSIONS: Our findings suggest that it might be possible to differentiate mild from severe liver fibrosis using the cellular metabolic changes with hyperpolarized C-13 MRS and metabolic imaging.

Bioactive Nanoparticles for Cancer Immunotherapy.

Currently, immunotherapy is considered to be one of the effective treatment modalities for cancer. All the developments and discoveries in this field up to the recent Nobel Prize add to the interest for research into this vast area of study. Targeting tumor environment as well as the immune system is a suitable strategy to be applied for cancer treatment. Usage of nanoparticle systems for delivery of immunotherapeutic agents to the body being widely studied and found to be a promising area of research to be considered and investigated further. Nanoparticles for immunotherapy would be one of the effective treatment options for cancer therapy in the future due to their high specificity, efficacy, ability to diagnose, imaging, and therapeutic effect. Among the many nanoparticle systems, polylactic-co-glycolic acid (PLGA) nanoparticles, liposomes, micelles, gold nanoparticles, iron oxide, dendrimers, and artificial exosomes are widely used for immunotherapy of cancer. Moreover, the combination therapy found to be the more effective way of treating the tumor. Here, we review the current trends in nanoparticle therapy and efficiency of these nanosystems in delivering antigens, adjuvants, therapeutic drugs, and other immunotherapeutic agents. This review summarizes the currently available bioactive nanoparticle systems for cancer immunotherapy.

Implantable chemothermal brachytherapy seeds: A synergistic approach to brachytherapy using polymeric dual drug delivery and hyperthermia for malignant solid tumor ablation.

Chemothermal brachytherapy seeds have been developed using a combination of polymeric dual drug chemotherapy and alternating magnetic field induced hyperthermia. The synergistic effect of chemotherapy and hyperthermia brachytherapy has been investigated in a way that has never been performed before, with an in-depth analysis of the cancer cell inhibition property of the new system. A comprehensive in vivo study on athymic mice model with SCC7 tumor has been conducted to determine optimal arrays and specifications of the chemothermal seeds. Dual drug chemotherapy has been achieved via surface deposition of polydopamine that carries bortezomib, and also via loading an acidic pH soluble hydrogel that contains 5-Fluorouracil inside the chemothermal seed; this increases the drug loading capacity of the chemothermal seed, and creates dual drug synergism. An external alternating magnetic field has been utilized to induce hyperthermia conditions, using the inherent ferromagnetic property of the nitinol alloy used as the seed casing. The materials used in this study were fully characterized using FESEM, H1 NMR, FT-IR, and XPS to validate their properties. This new approach to experimental cancer treatment is a pilot study that exhibits the potential of thermal brachytherapy and chemotherapy as a combined treatment modality.

MHI-148 Cyanine Dye Conjugated Chitosan Nanomicelle with NIR Light-Trigger Release Property as Cancer Targeting Theranostic Agent.

PURPOSE: Paclitaxel (PTX) loaded hydrophobically modified glycol chitosan (HGC) micelle is biocompatible in nature, but it requires cancer targeting ability and stimuli release property for better efficiency. To improve tumor retention and drug release characteristic of HGC-PTX nanomicelles, we conjugated cancer targeting heptamethine dye, MHI-148, which acts as an optical imaging agent, targeting moiety and also trigger on-demand drug release on application of NIR 808 nm laser. PROCEDURES: The amine group of glycol chitosan modified with hydrophobic 5ß-cholanic acid and the carboxyl group of MHI-148 were bonded by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide chemistry. Paclitaxel was loaded to MHI-HGC nanomicelle by an oil-in-water emulsion method, thereby forming MHI-HGC-PTX. RESULTS: Comparison of near infrared (NIR) dyes, MHI-148, and Flamma-774 conjugated to HGC showed higher accumulation for MHI-HGC in 4T1 tumor and 4T1 tumor spheroid. In vitro studies showed high accumulation of MHI-HGC-PTX in 4T1 and SCC7 cancer cell lines compared to NIH3T3 cell line. In vivo fluorescence imaging of the 4T1 and SCC7 tumor showed peak accumulation of MHI-HGC-PTX at day 1 and elimination from the body at day 6. MHI-HGC-PTX showed good photothermal heating ability (50.3 °C), even at a low concentration of 33 µg/ml in 1 W/cm2 808 nm laser at 1 min time point. Tumor reduction studies in BALB/c nude mice with SCC7 tumor showed marked reduction in MHI-HGC-PTX in the PTT group combined with photothermal therapy compared to MHI-HGC-PTX in the group without PTT. CONCLUSION: MHI-HGC-PTX is a cancer theranostic agent with cancer targeting and optical imaging capability. Our studies also showed that it has cancer targeting property independent of tumor type and tumor reduction property by combined photothermal and chemotherapeutic effects.

Electromagnetic manipulation enabled calcium alginate Janus microsphere for targeted delivery of mesenchymal stem cells.

We prepared Janus microspheres based on sodium alginate for the encapsulation of mesenchymal stem cells (MSC) in one compartment and iron oxide nanoparticles (IONP) or a drug in the second compartment. 4% percent sodium alginate solution was allowed to pass through a septum-theta capillary device and react with 2.5% calcium chloride to allow crosslinking to occur in the solution, forming calcium alginate Janus microspheres. Physico-chemical characterization of microspheres was done by FTIR, TGA, and XRD after loading of stem cells and IONP/drug. The mechanical integrity of microspheres was tested at different time points, which showed that 4% alginate microspheres were mechanically stable for a long period of time. Live/dead staining of MSCs alone and the MTS assay of MSCs and DMSO co-loaded were performed, which showed less toxicity to MSC in the Janus configuration. IONP/MSC-loaded Janus microspheres were tested by magnetic manipulation for targeted MSC delivery for cartilage repair using an electromagnetic manipulation (EMM) device. Janus microspheres can be used for targeted stem cell/drug delivery using EMM for cartilage repair in the near future.

Hyaluronic Acid-Based Nanomaterials for Cancer Therapy.

Hyaluronic acid (HA) is a nonsulfated glycosaminoglycan and a major component of the extracellular matrix. HA is overexpressed by numerous tumor cells, especially tumor-initiating cells. HA-based nanomaterials play in importance role in drug delivery systems. HA is used in various types of nanomaterials including micelle, polymersome, hydrogel, and inorganic nanoparticle formulations. Many experiments show that HA-based nanomaterials can serve as a platform for targeted chemotherapy, gene therapy, immunotherapy, and combination therapy with good potential for future biomedical applications in cancer treatment.

Nanoparticles for the treatment of liver fibrosis.

Chronic liver diseases represent a global health problem due to their high prevalence worldwide and the limited available curative treatment options. They can result from various causes, both infectious and noninfectious diseases. The application of nanoparticle (NP) systems has emerged as a rapidly evolving area of interest for the safe delivery of various drugs and nucleic acids for chronic liver diseases. This review presents the pathogenesis, diagnosis and the emerging nanoparticulate systems used in the treatment of chronic liver diseases caused by liver fibrosis. Activated hepatic stellate cell (HSC) is considered to be the main mechanism for liver fibrosis. Ultrasonography and magnetic resonance imaging techniques are widely used noninvasive diagnostic methods for hepatic fibrosis. A variety of nanoparticulate systems are mainly focused on targeting HSC in the treatment of hepatic fibrosis. As early liver fibrosis is reversible by current NP therapy, it is being studied in preclinical as well as clinical trials. Among various nanoparticulate systems, inorganic NPs, liposomes and nanomicelles have been widely studied due to their distinct properties to deliver drugs as well as other therapeutic moieties. Liposomal NPs in clinical trials is considered to be a milestone in the treatment of hepatic fibrosis. Currently, NP therapy for liver fibrosis is updating fast, and hopefully, it can be the future remedy for liver fibrosis.

Effectiveness of Losartan-Loaded Hyaluronic Acid (HA) Micelles for the Reduction of Advanced Hepatic Fibrosis in C3H/HeN Mice Model.

Advanced hepatic fibrosis therapy using drug-delivering nanoparticles is a relatively unexplored area. Angiotensin type 1 (AT1) receptor blockers such as losartan can be delivered to hepatic stellate cells (HSC), blocking their activation and thereby reducing fibrosis progression in the liver. In our study, we analyzed the possibility of utilizing drug-loaded vehicles such as hyaluronic acid (HA) micelles carrying losartan to attenuate HSC activation. Losartan, which exhibits inherent lipophilicity, was loaded into the hydrophobic core of HA micelles with a 19.5% drug loading efficiency. An advanced liver fibrosis model was developed using C3H/HeN mice subjected to 20 weeks of prolonged TAA/ethanol weight-adapted treatment. The cytocompatibility and cell uptake profile of losartan-HA micelles were studied in murine fibroblast cells (NIH3T3), human hepatic stellate cells (hHSC) and FL83B cells (hepatocyte cell line). The ability of these nanoparticles to attenuate HSC activation was studied in activated HSC cells based on alpha smooth muscle actin (α-sma) expression. Mice treated with oral losartan or losartan-HA micelles were analyzed for serum enzyme levels (ALT/AST, CK and LDH) and collagen deposition (hydroxyproline levels) in the liver. The accumulation of HA micelles was observed in fibrotic livers, which suggests increased delivery of losartan compared to normal livers and specific uptake by HSC. Active reduction of α-sma was observed in hHSC and the liver sections of losartan-HA micelle-treated mice. The serum enzyme levels and collagen deposition of losartan-HA micelle-treated mice was reduced significantly compared to the oral losartan group. Losartan-HA micelles demonstrated significant attenuation of hepatic fibrosis via an HSC-targeting mechanism in our in vitro and in vivo studies. These nanoparticles can be considered as an alternative therapy for liver fibrosis.

Hyaluronic acid conjugated superparamagnetic iron oxide nanoparticle for cancer diagnosis and hyperthermia therapy.

Recently, superparamagnetic iron oxide nanoparticles (SPIONs) have been prepared for magnetic resonance (MR) imaging and hyperthermia therapy. Here, we have developed hyaluronic acid (HA) coated SPIONs primarily for use in a hyperthermia application with an MR diagnostic feature with hydrodynamic size measurement of 176nm for HA-PEG10-SPIONs and 149nm for HA-SPIONs. HA-coated SPIONs (HA-SPIONs) were prepared to target CD44-expressed cancer where the carrier was conjugated to PEG for analyzing longer circulation in blood as well as for biocompatibility (HA-PEG10 SPIONs). Characterization was conducted with TEM (shape), DLS (size), ELS (surface charge), TGA (content of polymer) and MRI (T2-relaxation time). The heating ability of both the HA-SPIONs and HA-PEG10-SPIONs was studied by AMF and SAR calculation. Cellular level tests were conducted using SCC7 and NIH3T3 cell lines to confirm cell viability and cell specific uptake. HA-SPIONs and HA-PEG10-SPIONs were injected to xenograft mice bearing the SCC7 cell line for MRI cancer diagnosis. We found that HA-SPION-injected mice tumors showed nearly 40% MR T2 contrast compared to the 20% MR T2 contrast of the HA-PEG10-SPION group over a 3h time period. Finally, in vitro hyperthermia studies were conducted in the SCC7 cell line that showed less than 40% cell viability for both HA-SPIONs and HA-PEG10-SPIONs in AMF treated cells. In conclusion, HA-SPIONs were targeted specifically to the CD44, and the hyperthermia effect of HA-SPIONs and HA-PEG10-SPIONs was found to be significant for future studies.

Di-Sulfide Linked Polyethylenimine Coated Gold Nanoparticles as a Non-Viral Gene Delivery Agent in NIH-3T3 Mouse Embryonic Fibroblast.

Di-sulfide linked polyethylenimine coated gold nanoparticles (ssPEI-GNPs) of 20 nm size was prepared in order to deliver the genes to target site. DLS and TEM analysis demonstrated that the GNPs have average size of 13 nm in diameter. Upon coating the GNPs with ssPEI in the weight ratio of 1:3, the average hydrodynamic diameter of the ssPEI-GNPs was found to 19±1.14 nm and a zeta potential value 41±1.23 mV was observed. TEM analysis of ssPEI-GNPs demonstrated that the nanoparticles have spherical morphology. Thermogravemetric analysis of the prepared ssPEI-GNPs showed that the estimated composition of the ssPEI coated over the GNPs was approximately 5% (w/w). Gene expression capabilities of the nanoparticles were confirmed by fluorescent microscopy and luciferase assay, which demonstrated the transgene delivery capability of the ssPEI-GNPs. These results demonstrate that ssPEI-GNPs could be used as gene delivery agent.

MR detection of LPS-induced neutrophil activation using mannan-coated superparamagnetic iron oxide nanoparticles.

PURPOSE: The purpose of this study was to investigate the potential of the phagocytic activity of lipopolysaccharide (LPS) induced neutrophils that are mannan coated with superparamagnetic iron oxide nanoparticles (M-SPION). PROCEDURES: Human neutrophils were divided into control and LPS groups. The neutrophils were labeled with M-SPION and dextran-coated SPION. After labeling of M-SPION, the mean signal intensity (SI) of the LPS group was significantly lower than that of the control group. RESULTS: The labeling of both control and LPS groups with M-SPION showed significantly lower SI than those labeled with D-SPION. After labeling with M-SPION, the intracellular iron uptake of neutrophil in Prussian blue staining was markedly demonstrated in the LPS group, but not in the control group. M-SPION was more effective than D-SPION in the labeling of neutrophils in vitro. CONCLUSIONS: The in vitro labeling technique of LPS neutrophil with M-SPION on MR imaging could be developed into a diagnostic method of LPS-induced neutrophils.

Establishment of a protocol for determining gastrointestinal transit time in mice using barium and radiopaque markers.

OBJECTIVE: The purpose of this study was to establish a minimally invasive and reproducible protocol for estimating the gastrointestinal (GI) transit time in mice using barium and radiopaque markers. MATERIALS AND METHODS: Twenty 5- to 6-week-old Balb/C female mice weighing 19-21 g were used. The animals were divided into three groups: two groups that received loperamide and a control group. The control group (n = 10) animals were administered physiological saline (1.5 mL/kg) orally. The loperamide group I (n = 10) and group II (n = 10) animals were administered 5 mg/kg and 10 mg/kg loperamide orally, respectively. Thirty minutes after receiving the saline or loperamide, the mice was administered 80 µL of barium solution and six iron balls (0.5 mm) via the mouth and the upper esophagus by gavage, respectively. Afterwards, the mice were continuously monitored with fluoroscopic imaging in order to evaluate the swallowing of the barium solution and markers. Serial fluoroscopic images were obtained at 5- or 10-min intervals until all markers had been excreted from the anal canal. For analysis, the GI transit times were subdivided into intestinal transit times (ITTs) and colon transit times (CTTs). RESULTS: The mean ITT was significantly longer in the loperamide groups than in the control group (p < 0.05). The mean ITT in loperamide group II (174.5 ± 32.3) was significantly longer than in loperamide group I (133.2 ± 24.2 minute) (p < 0.05). The mean CTT was significantly longer in loperamide group II than in the control group (p < 0.05). Also, no animal succumbed to death after the experimental procedure. CONCLUSION: The protocol for our study using radiopaque markers and barium is reproducible and minimally invasive in determining the GI transit time of the mouse model.