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3.
ACS Omega ; 6(36): 23117-23128, 2021 Sep 14.
Article in English | MEDLINE | ID: mdl-34549113

ABSTRACT

Microfluidic-based synthesis is a powerful technique to prepare well-defined homogenous nanoparticles (NPs). However, the mechanisms defining NP properties, especially size evolution in a microchannel, are not fully understood. Herein, microfluidic and bulk syntheses of riboflavin (RF)-targeted poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG-RF) micelles were evaluated experimentally and computationally. Using molecular dynamics (MD), a conventional "random" model for bulk self-assembly of PLGA-PEG-RF was simulated and a conceptual "interface" mechanism was proposed for the microfluidic self-assembly at an atomic scale. The simulation results were in agreement with the observed experimental outcomes. NPs produced by microfluidics were smaller than those prepared by the bulk method. The computational approach suggested that the size-determining factor in microfluidics is the boundary of solvents in the entrance region of the microchannel, explaining the size difference between the two experimental methods. Therefore, this computational approach can be a powerful tool to gain a deeper understanding and optimize NP synthesis.

4.
Elife ; 102021 01 12.
Article in English | MEDLINE | ID: mdl-33432925

ABSTRACT

The purpose of preclinical research is to inform the development of novel diagnostics or therapeutics, and the results of experiments on animal models of disease often inform the decision to conduct studies in humans. However, a substantial number of clinical trials fail, even when preclinical studies have apparently demonstrated the efficacy of a given intervention. A number of large-scale replication studies are currently trying to identify the factors that influence the robustness of preclinical research. Here, we discuss replications in the context of preclinical research trajectories, and argue that increasing validity should be a priority when selecting experiments to replicate and when performing the replication. We conclude that systematically improving three domains of validity - internal, external and translational - will result in a more efficient allocation of resources, will be more ethical, and will ultimately increase the chances of successful translation.


Subject(s)
Research Design/statistics & numerical data , Animals , Disease Models, Animal , Humans
5.
Invest Radiol ; 55(8): 507-514, 2020 08.
Article in English | MEDLINE | ID: mdl-32224718

ABSTRACT

OBJECTIVES: Magnetic resonance imaging (MRI) is considered to be well tolerated by laboratory animals. However, no systematic study has been performed yet, proving this assumption. Therefore, the aim of this study was to investigate the possible effects of longitudinal native and contrast-enhanced (CE) 1-T and 7-T MRI examinations on mouse welfare as well as 4T1 breast cancers progression and therapy response. MATERIAL AND METHODS: Forty-seven healthy and 72 breast cancer-bearing mice (4T1) were investigated. One-Tesla (ICON) and 7-T (Biospec) MRI measurements were performed thrice per week under isoflurane anesthesia in healthy BALB/c mice for 4 weeks and 3 times within 2 weeks in tumor-bearing animals. Animal welfare was examined by an observational score sheet, rotarod performance, heart rate measurements, and assessment of fecal corticosterone metabolites. Furthermore, we investigated whether CE-MRI influences the study outcome. Therefore, hemograms and organ weights were obtained, and 4T1 tumor growth, perfusion, immune cell infiltration, as well as response to the multikinase inhibitor regorafenib were investigated. Statistical comparisons between groups were performed using analysis of variance and Tukey or Bonferroni post hoc tests. RESULTS: Mice showed no alterations in the observational score sheet rating, rotarod performance, heart rate, and fecal corticosterone metabolites (P > 0.05) after repeated MRI at both field strengths. However, spleen weights were reduced in all healthy mouse groups that received isoflurane anesthesia (P < 0.001) including the groups investigated by 1-T and 7-T MRI (P = 0.02). Neither tumor progression nor response to the regorafenib treatment was affected by isoflurane anesthesia or CE-MRI monitoring. Furthermore, immunohistological tumor analysis did not indicate an effect of isoflurane and MRI on macrophage infiltration of tumors, perfusion of tumor vessels, and apoptotic cell rate (P > 0.05). CONCLUSIONS: Repeated MRI did not influence the welfare of mice and did not affect tumor growth and therapy response of 4T1 tumors. However, systemic immunological effects of isoflurane anesthesia need to be considered to prevent potential bias.


Subject(s)
Animal Welfare , Magnetic Resonance Imaging , Animals , Corticosterone/metabolism , Female , Mice , Mice, Inbred BALB C
6.
Mol Imaging Biol ; 22(3): 623-633, 2020 06.
Article in English | MEDLINE | ID: mdl-31396770

ABSTRACT

PURPOSE: Evaluation of [68Ga]NODAGA-duramycin as a positron emission tomography (PET) tracer of cell death for whole-body detection of chemotherapy-induced organ toxicity. PROCEDURES: Tracer specificity of Ga-68 labeled NODAGA-duramycin was determined in vitro using competitive binding experiments. Organ uptake was analyzed in untreated and doxorubicin, busulfan, and cisplatin-treated mice 2 h after intravenous injection of [68Ga]NODAGA-duramycin. In vivo data were validated by immunohistology and blood parameters. RESULTS: In vitro experiments confirmed specific binding of [68Ga]NODAGA-duramycin. Organ toxicities were detected successfully using [68Ga]NODAGA-duramycin PET/X-ray computed tomography (CT) and confirmed by immunohistochemistry and blood parameter analysis. Organ toxicities in livers and kidneys showed similar trends in PET/CT and immunohistology. Busulfan and cisplatin-related organ toxicities in heart, liver, and lungs were detected earlier by PET/CT than by blood parameters and immunohistology. CONCLUSION: [68Ga]NODAGA-duramycin PET/CT was successfully applied to non-invasively detect chemotherapy-induced organ toxicity with high sensitivity in mice. It, therefore, represents a promising alternative to standard toxicological analyses with a high translational potential.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/adverse effects , Bacteriocins , Gallium Radioisotopes , Kidney/drug effects , Kidney/diagnostic imaging , Liver/drug effects , Liver/diagnostic imaging , Neoplasms/drug therapy , Peptides , Acetates/chemistry , Acetates/metabolism , Animals , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Bacteriocins/chemistry , Bacteriocins/pharmacokinetics , Busulfan/administration & dosage , Cisplatin/administration & dosage , Doxorubicin/administration & dosage , Female , Gallium Radioisotopes/chemistry , Gallium Radioisotopes/pharmacokinetics , Heterocyclic Compounds, 1-Ring/chemistry , Heterocyclic Compounds, 1-Ring/metabolism , Kidney/metabolism , Kidney/pathology , Liver/metabolism , Liver/pathology , Mice , Mice, Inbred BALB C , Neoplasms/pathology , Peptides/chemistry , Peptides/pharmacokinetics , Positron Emission Tomography Computed Tomography/methods , Radiopharmaceuticals/chemistry , Radiopharmaceuticals/pharmacokinetics , Tissue Distribution
7.
Front Pharmacol ; 9: 1260, 2018.
Article in English | MEDLINE | ID: mdl-30450050

ABSTRACT

Nanomedicines can be used for a variety of cancer therapies including tumor-targeted drug delivery, hyperthermia, and photodynamic therapy. Poly (lactic-co-glycolic acid) (PLGA)-based materials are frequently used in such setups. This review article gives an overview of the properties of previously reported PLGA nanoparticles (NPs), their behavior in biological systems, and their use for cancer therapy. Strategies are emphasized to target PLGA NPs to the tumor site passively and actively. Furthermore, combination therapies are introduced that enhance the accumulation of NPs and, thereby, their therapeutic efficacy. In this context, the huge number of reports on PLGA NPs used as drug delivery systems in cancer treatment highlight the potential of PLGA NPs as drug carriers for cancer therapeutics and encourage further translational research.

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