ABSTRACT
INTRODUCTION: Maintaining a better physical and mental health status is an important issue for older adults in their later life. Thus, the study's purpose was to evaluate the association between body mass index (BMI) and mental health status in older adults aged 65 years old or above residing in communities of Taipei City, Taiwan. METHODS: We carried out secondary data analysis with data from a volunteer-based health examination project for older adults >65 years old residing in Taipei City from 2006 to 2010 with a retrospective study design. BMI, calculated by standardized measuring procedures for height and weight, and mental health status, evaluated by 5-item Brief Symptom Rating Scale (BSRS-5), were collected at their first visits of health examination. A BSRS-5 score ≥6 was considered an inferior mental health status for the outcome. In statistical analysis, univariable and multivariable logistic regressions were adopted to estimate the relative risk of inferior mental health status, treating BMI as the major exposure of interest. RESULTS: A total of 90,576 subjects were involved, with a mean age of 73.38 years old (SD = 6.64 years) and 49.21% females. With confounders controlled, compared to normal or overweight (23 ≤ BMI <30), an adjusted OR of 1.23 (95% CI: 1.18, 1.29) on inferior mental health status was detected for the underweight group (BMI <23) significantly. Adjusted OR for those obese (BMI â§30) was 0.87 (95% CI: 0.79, 0.96). Significantly elevated ORs of underweight were found for both genders, but the significantly protective effect of obese was only detected for females. CONCLUSION: Keeping an appropriate weight or even being overweighted might be beneficial for older adults dwelling in the community, especially for males.
Subject(s)
Independent Living , Thinness , Humans , Female , Male , Aged , Body Mass Index , Retrospective Studies , Overweight , Obesity/epidemiology , Health StatusABSTRACT
PURPOSE: Our study aimed to evaluate non-inferiority of ProDisc-C to anterior cervical discectomy and fusion (ACDF) in terms of clinical outcomes and incidence of adjacent segment disease (ASD) at 24-months post-surgery in Asian patients with symptomatic cervical disc disease (SCDD). METHODS: This multicentre, prospective, randomized controlled trial was initiated after ethics committee approval at nine centres (China/Hong Kong/Korea/Singapore/Taiwan). Patients with single-level SCDD involving C3-C7-vertebral segments were randomized (2:1) into: group-A treated with ProDisc-C and group-B with ACDF. Assessments were conducted at baseline, 6-weeks, 3/6/12/18/24-months post-surgery and annually thereafter till 84-months. Primary endpoint was overall success at 24-months, defined as composite of: (1) ≥ 20% improvement in neck disability index (NDI); (2) maintained/improved neurologic parameters; (3) no implant removal/revision/re-operation at index level; and (4) no adverse/severe/life-threatening events. RESULTS: Of 120 patients (80ProDisc-C,40ACDF), 76 and 37 were treated as per protocol (PP). Overall success (PP) was 76.5% in group-A and 81.8% in group-B at 24-months (p = 0.12), indicating no clear non-inferiority of ProDisc-C to ACDF. Secondary outcomes improved for both groups with no significant inter-group differences. Occurrence of ASD was higher in group-B with no significant between-group differences. Range of motion (ROM) was sustained with ProDisc-C but lost with ACDF at 24-months. CONCLUSION: Cervical TDR with ProDisc-C is feasible, safe, and effective for treatment of SCDD in Asians. No clear non-inferiority was demonstrated between ProDisc-C and ACDF. However, patients treated with ProDisc-C demonstrated significant improvement in NDI, neurologic success, pain scores, and 36-item-short-form survey, along with ROM preservation at 24-months. Enrolment difficulties resulted in inability to achieve pre-planned sample size to prove non-inferiority. Future Asian-focused, large-scale studies are needed to establish unbiased efficacy of ProDisc-C to ACDF.
Subject(s)
Intervertebral Disc Degeneration , Spinal Fusion , Total Disc Replacement , Asian People , Cervical Vertebrae/surgery , Diskectomy/methods , Follow-Up Studies , Humans , Intervertebral Disc Degeneration/etiology , Intervertebral Disc Degeneration/surgery , Intervertebral Disc Displacement , Prospective Studies , Range of Motion, Articular , Spinal Fusion/methods , Total Disc Replacement/methods , Treatment OutcomeABSTRACT
In-stent restenosis is a serious concern for patients treated through the stenting procedure, although this can be solved using drug-eluting stents and/or drug-eluting balloon catheters. However, the chemical agents released from the drug-eluting layer for inhibiting smooth muscle cell (SMC) migration are inevitably associated with damage to vascular endothelial cell (ECs). The present in vitro study used a distinct strategy, in which a smart gene (phEGR1-PKCδ, an engineered plasmid consists of an SMC-specific promoter (human early growth response 1, hEGR1 promoter) ligated with a gene encoding apoptosis-inducing protein (protein kinase C-delta, PKCδ) was incorporated into a novel gene vehicle (Au cluster-incorporated polyethylenimine/carboxymethyl hexanoyl chitosan, PEI-Au/CHC) to form the PEI-Au/CHC/phEGR1-PKCδ complex, which was proposed for the selective inhibition of SMC proliferation. It was found that the cell viability of SMCs receiving the PEI-Au/CHC/phEGR1-PKCδ complex under simulated inflammation conditions was significantly lower than that of the ECs receiving the same treatment. In addition, the PEI-Au/CHC/phEGR1-PKCδ complex did not demonstrate an inhibitory effect on EC proliferation and migration under simulated inflammation conditions. Finally, the PEI-Au/CHC/phEGR1-PKCδ complexes coated onto a balloon catheter used in percutaneous transluminal coronary angioplasty (PTCA) could be transferred to both the ECs and the SMC layer of Sprague Dawley (SD) rat aortas ex vivo. These preliminary in vitro results suggest that the newly developed approach proposed in the present study might be a potential treatment for reducing the incidence rate of in-stent restenosis and late thrombosis in the future.
Subject(s)
Early Growth Response Protein 1/metabolism , Genetic Therapy/methods , Muscle, Smooth, Vascular/metabolism , Myocytes, Smooth Muscle/metabolism , Protein Kinase C-delta/metabolism , Animals , Aorta/cytology , Aorta/metabolism , Apoptosis/genetics , Cell Survival/genetics , Coronary Restenosis/genetics , Coronary Restenosis/therapy , Drug Carriers/chemistry , Drug-Eluting Stents , Early Growth Response Protein 1/genetics , Endothelial Cells/cytology , Endothelial Cells/metabolism , Genetic Engineering , Microscopy, Fluorescence , Muscle, Smooth, Vascular/cytology , Myocytes, Smooth Muscle/cytology , Nanostructures/chemistry , Protein Kinase C-delta/genetics , Rats, Sprague-DawleyABSTRACT
Evidence regarding the association between BMI and mortality in tuberculosis (TB) patients is limited and inconsistent. We investigated the impact of BMI on TB-specific and non-TB-specific mortality with respect to different timing of death. All Taiwanese adults with TB in Taipei were included in a retrospective cohort study in 2012-2014. Multinomial Cox proportional hazards regression was used to evaluate the associations between BMI, cause-specific mortality and timing of death. Of 2410 eligible patients, 86·0 % (2061) were successfully treated, and TB-specific and non-TB-specific mortality occurred for 2·2 % (54) and 13·9 % (335), respectively. After controlling for potential confounders, underweight was significantly associated with a higher risk of all-cause mortality (adjusted hazard ratio (AHR) 1·57; 95 % CI 1·26, 1·95), whereas overweight was not. When cause-specific death was considered, underweight was associated with an increased risk of either TB-specific (AHR 1·85; 95 % CI 1·03, 3·33) or non-TB-specific death (AHR 1·52; 95 % CI 1·19, 1·95) during treatment. With joint consideration of cause-specific and timing of death, underweight only significantly increased the risk of TB-specific (AHR 2·23; 95 % CI 1·09, 4·59) and non-TB-specific mortality (AHR 1·81; 95 % CI 1·29, 2·55) within the first 8 weeks of treatment. This study suggests that underweight increases the risk of early death in TB patients during treatment.
Subject(s)
Thinness/complications , Tuberculosis/mortality , Adolescent , Adult , Aged , Body Mass Index , Female , Follow-Up Studies , Humans , Male , Middle Aged , Proportional Hazards Models , Retrospective Studies , Risk Factors , Socioeconomic Factors , Taiwan/epidemiology , Tuberculosis/etiology , Young AdultABSTRACT
The standard treatment for early-stage breast cancer involves breast-conserving surgery followed by adjuvant radiotherapy. However, approximately 20 % of patients experience distant metastasis, and adjuvant radiotherapy often leads to radiation-induced skin fibrosis (RISF). In this study, we develop an on-site injectable formulation composed of selenocystamine (SeCA) and hyaluronic acid (HyA), referred to as SeCA cross-linked HyA (SCH) agent, and investigate its potential to mitigate metastasis and prevent RISF associated with breast cancer therapy. SCH agents are synthesized using the nanoprecipitation method to modulate cell-cell tight junctions and tissue inflammation. The toxicity assessments reveal that SCH agents with a higher Se content (Se payload 17.4 µg/mL) are well tolerated by L929 cells compared to SeCA (Se payload 3.2 µg/mL). In vitro, SCH agents significantly enhance cell-cell tight junctions and effectively mitigate migration and invasion of breast cancer cells (4T1). In vivo, SCH agents mitigate distant lung metastasis. Furthermore, in animal models, SCH agents reduce RISF and promote wound repair. These findings highlight the potential of SCH agents as a novel therapeutic formulation for effectively mitigating metastasis and reducing RISF. This holds great promise for improving clinical outcomes in breast cancer patients undergoing adjuvant radiotherapy.
Subject(s)
Breast Neoplasms , Fibrosis , Hyaluronic Acid , Hyaluronic Acid/chemistry , Animals , Female , Breast Neoplasms/pathology , Breast Neoplasms/drug therapy , Mice , Fibrosis/drug therapy , Cell Line, Tumor , Humans , Mice, Inbred BALB C , Cystamine/chemistry , Cystamine/pharmacology , Skin/drug effects , Skin/pathology , Skin/radiation effects , Cell Movement/drug effects , InjectionsABSTRACT
Purpose: Glioblastoma is a highly aggressive brain tumor with universally poor outcomes. Recent progress in immune checkpoint inhibitors has led to increased interest in their application in glioblastoma. Nonetheless, the unique immune milieu in the brain has posed remarkable challenges to the efficacy of immunotherapy. We aimed to leverage the radiation-induced immunogenic cell death to overcome the immunosuppressive network in glioblastoma. Methods: We developed a novel approach using the gold-core silica-shell nanoparticles (Au@SiO2 NPs) in combination with low-dose radiation to enhance the therapeutic efficacy of the immune checkpoint inhibitor (atezolizumab) in brain tumors. The biocompatibility, immune cell recruitment, and antitumor ability of the combinatorial strategy were determined using in vitro assays and in vivo models. Results: Our approach successfully induced the migration of macrophages towards brain tumors and promoted cancer cell apoptosis. Subcutaneous tumor models demonstrated favorable safety profiles and significantly enhanced anticancer effects. In orthotopic brain tumor models, the multimodal therapy yielded substantial prognostic benefits over any individual modalities, achieving an impressive 40% survival rate. Conclusion: In summary, the combination of Au@SiO2 NPs and low-dose radiation holds the potential to improve the clinical efficacy of immune checkpoint inhibitors. The synergetic strategy modulates tumor microenvironments and enhances systemic antitumor immunity, paving a novel way for glioblastoma treatment.
Subject(s)
Brain Neoplasms , Glioblastoma , Nanoparticles , Humans , Silicon Dioxide/therapeutic use , Glioblastoma/drug therapy , Gold/therapeutic use , Immune Checkpoint Inhibitors/therapeutic use , Immunotherapy , Brain Neoplasms/radiotherapy , Brain Neoplasms/drug therapy , Cell Line, Tumor , Tumor MicroenvironmentABSTRACT
It is vital to remove residual tumor cells after resection to avoid the recurrence and metastasis of osteosarcoma. In this study, a mineral nanomedicine, europium-doped calcium fluoride (CaF2:Eu) nanoparticles (NPs), is developed to enhance the efficacy of adjuvant radiotherapy (i.e., surgical resection followed by radiotherapy) for tumor cell growth and metastasis of osteosarcoma. In vitro studies show that CaF2:Eu NPs (200 µg/mL) exert osteosarcoma cell (143B)-selective toxicity and migration-inhibiting effects at a Eu dopant amount of 2.95 atomic weight percentage. These effects are further enhanced under X-ray irradiation (6 MeV, 4 Gy). Furthermore, in vivo tests show that intraosseous injection of CaF2:Eu NPs and X-ray irradiation have satisfactory therapeutic efficacy in controlling primary tumor size and inhibiting primary tumor metastasis. Overall, our results suggest that CaF2:Eu NPs with their osteosarcoma cell (143B)-selective toxicity and migration-inhibiting effects combined with radiotherapy might be nanomedicines for treating osteosarcoma after tumor resection.
Subject(s)
Antineoplastic Agents/therapeutic use , Calcium Fluoride/therapeutic use , Europium/therapeutic use , Metal Nanoparticles/therapeutic use , Osteosarcoma/drug therapy , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/toxicity , Calcium Fluoride/chemistry , Calcium Fluoride/toxicity , Cell Line, Tumor , Cell Movement/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , Combined Modality Therapy , Europium/chemistry , Europium/toxicity , G2 Phase Cell Cycle Checkpoints/drug effects , Humans , Metal Nanoparticles/chemistry , Metal Nanoparticles/toxicity , Mice , Radiotherapy, AdjuvantABSTRACT
Fibers comprised of reconstituted type I collagen were prepared by a gravity filament forming process and crosslinked with 0.1% glutaraldehyde. These fibers have a crosslinking index of about 90% (89.89 ± 1.82%) with higher denature temperature (74.43 ± 0.08°C) as compared to that without glutaraldehyde treatment (52.1 ± 0.17°C). The ultimate tensile strength of the collagen fibers increases from 99.4 ± 12.9 to 174.4 ± 9.0 MPa after glutaraldehyde-crosslinking. L929 fibroblast cells were seeded and cultured using these newly developed collagen fibers. The fibroblast cells proliferated well and covered all surface areas of the collagen fiber. These collagen fibers have a great potential for application in 3-D tissue engineering.
Subject(s)
Biocompatible Materials/chemistry , Cell Proliferation/drug effects , Collagen Type I/chemistry , Fibroblasts/drug effects , Tissue Engineering/methods , Biocompatible Materials/pharmacology , Cell Culture Techniques , Collagen Type I/pharmacology , Cross-Linking Reagents/chemistry , Fibroblasts/cytology , Glutaral/chemistry , Materials Testing , Microscopy, Confocal , Microscopy, Electron, Scanning , Pressure , Tensile StrengthABSTRACT
Radiotherapy (RT), in combination with surgery, is an essential treatment strategy for oral cancer. Although irradiation provides effective control over tumor growth, the surrounding normal tissues are almost inevitably affected. With further understanding of the molecular mechanisms involved in radiation response and recent advances in nanotechnology, using gold nanoparticles as a radiosensitizer provides the preferential sensitization of tumor cells to radiation and minimizes normal tissue damage. Herein, we developed gold nano-sesame-beads (GNSbs), a gold-nanorod-seeded mesoporous silica nanoparticle, as a novel radioenhancer to achieve radiotherapy with a higher therapeutic index. GNSbs in combination with 2 Gy irradiation effectively enhanced the cytotoxic activity CAL-27 cells. The well-designed structure of GNSbs showed preferential cellular uptake by CAL-27 cells at 24 h after incubation. Gold nanorods with high density modified on mesoporous silica nanoparticles resulted in significant reactive oxygen species (ROS) formation after irradiation exposure compared with irradiation alone. Furthermore, GNSbs and irradiation induced more prominent DNA double-strand breaks and G2/M phase arrest in CAL-27 than those in L929. In animal studies, radiotherapy using GNSbs as a radiosensitizer showed significant suppression of tumor growth in an orthotopic model of oral cancer. These results demonstrate that using GNSbs as a radiosensitizer could possess clinical potential for the treatment of oral squamous carcinoma.
ABSTRACT
Osteosarcoma is insensitive to radiation. High-dose radiation is often used as a treatment but causes side effects in patients. Hence, it is important to develop tumor cell-- targeted radiotherapy that could improve radiotherapy efficiency on tumor cells and reduce the toxic effect on normal cells during radiation treatment. In this study, we developed an innovative method for treating osteosarcoma by using a novel radiation-enhancer (i.e., carboxymethyl-hexanoyl chitosan-coated self-assembled Au@Fe3O4 nanoparticles; CSAF NPs). CSAF NPs were employed together with 5-aminolevulinic acid (5- ALA) to achieve tumor cell-targeted radiotherapy. In this study, osteosarcoma cells (MG63) and normal cells (MC3T3-E1) were used for an in vitro investigation, in which reactive oxygen species (ROS) assay, cell viability assay, clonogenic assay, and western blot were used to confirm the treatment efficiency. The ROS assay showed that the combination of CSAF NPs and 5-ALA enhanced radiation-induced ROS production in tumor cells (MG63); however, this was not observed in normal cells (MC3T3-E1). The cell viability ratio of normal cells to tumor cells after treatment with CSAF NPs and 5-ALA reached 2.79. Moreover, the clonogenic assay showed that the radiosensitivity of MG63 cells was increased by the combination use of CSAF NPs and 5-ALA. This was supported by performing a western blot that confirmed the expression of cytochrome c (a marker of cell mitochondria damage) and caspase-3 (a marker of cell apoptosis). The results provide an essential basis for developing tumor-cell targeted radiotherapy by means of low-- dose radiation.
Subject(s)
Osteosarcoma , Aminolevulinic Acid , Apoptosis , Cell Line, Tumor , Cell Survival , Humans , Reactive Oxygen SpeciesABSTRACT
The application of radiotherapy (RT) to treat osteosarcoma (OS) has been limited, but this is starting to change as the ability to target radiation energy to niches improves. Furthermore, lung cancer from highly metastatic OS is a major cause of death, so it is critical to explore new strategies to tackle metastasis. In this study, we designed a nanoscale radiosensitizer by grafting 2-deoxy-d-glucose (2DG) onto graphene quantum dots (GQD) to achieve OS targeting and boost RT efficacy. Combining the use of 2DG-grafted GQDs (2DG-g-GQD) with RT produced a significant increase in oxidative stress response and DNA damage in the 143B OS cell line compared with RT alone. Moreover, 2DG-g-GQDs selectively associated with 143B cells, and demonstrated the inhibition of migration in a scratch assay. We also demonstrated remarkable improvement in their ability to inhibit tumour progression and lung metastasis in an OS xenograft mouse model. Our results show that the use of 2DG-g-GQDs as OS-targeting radiosensitizers improves their therapeutic outcome and exhibits potential for use in low-dose precision RT for OS.
Subject(s)
Deoxyglucose/chemistry , Graphite/chemistry , Osteosarcoma/radiotherapy , Quantum Dots/therapeutic use , Radiation-Sensitizing Agents/chemistry , Animals , Cell Line, Tumor , Cell Movement/drug effects , Cell Survival/drug effects , DNA Damage , Deoxyglucose/pharmacokinetics , Deoxyglucose/therapeutic use , Drug Delivery Systems , Glucose/chemistry , Glucose/pharmacokinetics , Glucose/therapeutic use , Graphite/pharmacokinetics , Graphite/therapeutic use , Humans , Mice , Neoplasm Metastasis/prevention & control , Osteosarcoma/metabolism , Osteosarcoma/pathology , Quantum Dots/chemistry , Radiation-Sensitizing Agents/pharmacokinetics , Radiation-Sensitizing Agents/therapeutic use , Reactive Oxygen Species/metabolism , Treatment OutcomeABSTRACT
Many non-antibiotic strategies, such as photocatalysis and photodynamic therapy, have been proposed to inhibit and/or kill bacteria. However, these approaches still have drawbacks such as insufficient bacterial specificity and the limited penetration depth of ultraviolet and near-infrared light. To overcome these limitations, we developed a bacteria-specific anti-bacterial technique via using low-dose X-ray. Graphene oxide quantum dots (GQDs, a multifunctional vehicle) conjugated with vancomycin (Van, a bacteria-targeting ligand) were assembled with Protoporphyrin IX (PpIX, a photo/radiation sensitizer) to yield a novel Van-GQDs/PpIX complex that specifically attached to Escherichia coli and efficiently generated intracellular reactive oxygen species following X-ray activation. Delivery using GQDs increased the PpIX/Van ratio in the target bacterial cell, damaged bacterial cell wall, and enhanced X-ray-induced PpIX activation. Hence, this approach allowed for the use of a low-dose X-ray to efficiently activate the Van-GQDs/PpIX complex to exert its bactericidal effects on Escherichia coli without damaging normal cells. Furthermore, the E. coli did not develop resistance to the proposed approach for at least 7 rounds of repeated administration during one week. Thus, this proposed vehicle exhibiting bacteria-specific X-ray-triggered toxicity is a promising alternative to antibiotics for treating serious bacterial infections occurring in deep-seated tissues/organs (e.g., osteomyelitis and peritonitis). STATEMENTS OF SIGNIFICANCE: Administration of antibiotics is the most common treatment modality for bacterial infections. However, in some cases, patient attributes such as age, health, tolerance to antibiotics do not allow for the use of high-dose antibiotics. In addition, some bacteria develop resistance to antibiotics because of improper and long-term use of these agents. Therefore, non-antibiotic strategies to treat deeply situated bacterial infections, such as osteomyelitis, are urgently needed for avoiding amputation. To date, several non-antibiotic approaches, such as Ag nanoparticles, graphene-based materials, photocatalysis, and photodynamic therapy have been proposed to inhibit and/or kill bacteria. However, the major challenges of photochemical strategies, specificity and limited penetration depth of light source, still remain for treating the deep-seated bacteria. To overcome these problems, we developed a novel nanovehicle that exerted toxic effects specifically on bacteria following activation by a deeply penetrative low-dose X-ray, without damaging normal cells. As such, it realizes a deeply photochemical route for treating the deep-seated bacteria.
Subject(s)
Escherichia coli/radiation effects , Nanoparticles/chemistry , Animals , Cell Line , Cell Survival/drug effects , Dose-Response Relationship, Radiation , Graphite/chemistry , Mice , Microbial Viability/drug effects , Quantum Dots/chemistry , Quantum Dots/ultrastructure , Reactive Oxygen Species/metabolism , Vancomycin/pharmacology , X-RaysABSTRACT
Radiotherapy, a common cancer treatment, often adversely affects the surrounding healthy tissue and/or cells. Some tumor tissue-focused radiation therapies have been developed to lower radiation-induced lesion formation; however, achieving tumor cell-targeted radiotherapy (i.e., precisely focusing the radiation efficacy to tumor cells) remains a challenge. In the present study, we developed a novel tumor cell-targeted radiotherapy, named targeted sensitization-enhanced radiotherapy (TSER), that exploits tumor-specific folic acid-conjugated carboxymethyl lauryl chitosan/superparamagnetic iron oxide (FA-CLC/SPIO) micelles to effectively deliver chlorin e6 (Ce6, a sonosensitizer) to mitochondria of HeLa cells under magnetic guidance. For the in vitro tests, the sensitization of Ce6 induced by ultrasound, that could weaken the radiation resistant ability of tumor cells, occurred only in Ce6-internalizing tumor cells. Therefore, low-dose X-ray irradiation, that was not harmful to normal cells, could exert high tumor cell-specific killing ability. The ratio of viable normal cells to tumor cells was increased considerably, from 7.8 (at 24h) to 97.1 (at 72h), after they had received TSER treatment. Our data suggest that TSER treatment significantly weakens tumor cells, resulting in decreased viability in vitro as well as decreased in vivo subcutaneous tumor growth in nude mice, while the adverse effects were minimal. Taken together, TSER treatment appears to be an effective, clinically feasible tumor cell-targeted radiotherapy that can solve the problems of traditional radiotherapy and photodynamic therapy.
Subject(s)
Chitosan/analogs & derivatives , Magnets/chemistry , Neoplasms/radiotherapy , Porphyrins/administration & dosage , Radiation-Sensitizing Agents/administration & dosage , Animals , Chitosan/chemistry , Chlorophyllides , Drug Delivery Systems , Female , Ferric Compounds/chemistry , Folic Acid/chemistry , HeLa Cells , Humans , Mice, Nude , Micelles , Neoplasms/pathology , Porphyrins/therapeutic use , Radiation-Sensitizing Agents/therapeutic useABSTRACT
A new micelle-forming material, folic acid-conjugated carboxymethyl lauryl chitosan (FA-CLC), and superparamagnetic iron oxide (SPIO) nanoparticles were used for preparing an imaging-guided drug vehicle (the FA-CLC/SPIO hybrid micelle) that demonstrates targeted delivery, imaging, and controlled release of hydrophobic agents. We found that the ratio of viable normal cells to tumor cells was increased prominently after delivery of camptothecin (CPT)-loaded FA-CLC/SPIO micelles and therapeutic sonication. In addition, a magnetic field could enhance the tumor-targeting effect of FA-CLC/SPIO micelles. Therefore, after sequential administration of magnetic attraction to CPT-loaded FA-CLC/SPIO micelles, and therapeutic sonication, the in vivo therapeutic efficacy of CPT was markedly enhanced. However, a nonfocused magnetic field could enhance the undesirable accumulation of iron-containing vehicles in the liver if the tumor (i.e., magnetic attraction site) is near the liver. We propose that magnetic attraction must be carefully applied, far from the liver.
Subject(s)
Antineoplastic Agents/administration & dosage , Chitosan/analogs & derivatives , Chitosan/chemistry , Ferric Compounds/chemistry , Folic Acid/analogs & derivatives , Folic Acid/chemistry , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacokinetics , Camptothecin/administration & dosage , Camptothecin/chemistry , Camptothecin/pharmacokinetics , Carbocyanines , Cell Line, Tumor , Delayed-Action Preparations , Drug Carriers , Female , Fluorescence , Fluorescent Dyes , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Magnetic Fields , Magnets , Mice, Nude , Micelles , Nanoparticles , SonicationABSTRACT
In the present study, a new bubble-forming material (carboxymethyl hexanoyl chitosan, CHC), together with superparamagnetic iron oxide (SPIO) nanoparticles, was employed to prepare image-guided bubbles for efficiently encapsulating and delivering hydrophobic agents to kill tumor cells. The results showed that CHC could be used for preparing not only micronized bubbles (CHC/SPIO MBs) to exhibit ultrasound imaging functionality but also nanosized bubbles (CHC/SPIO NBs) to exhibit magnetic resonance T2 image contrast. It was found that the amounts of SPIO nanoparticles and hexane during preparation process were the key factors to obtaining CHC/SPIO NBs. Most importantly, under in vitro cell culture conditions with the same amount of camptothecin (CPT) and therapeutic sonication, CPT-loaded CHC/SPIO NBs demonstrated more significant transcellular delivery and cytotoxicity than free CPT. Subsequently, an intratumoral injection was proposed for the in vivo administration of hydrophobic-agent-loaded CHC/SPIO NBs. After injection, the distribution of a hydrophobic dye (DiR, an agent with near-infrared (NIR) fluorescence used as a model drug) released from the CHC/SPIO NBs was tracked by an NIR imaging technique. A significant tumor-specific accumulation was observed in the mouse that received the DiR-loaded CHC/SPIO NBs; the same was not observed in the mouse that received the free dye (without incorporating with CHC/SPIO NBs). It is expected, in the future, both the dose of the therapeutic agent administered and its side effects can be significantly lowered by using novel CHC/SPIO NBs together with local delivery (intratumoral injection), targeted imaging and enhanced cellular uptake of the drug.