Quantum dots in axillary lymph node mapping: Biodistribution study in healthy mice

<p>Abstract</p> <p>Background</p> <p>Breast cancer is the first cause of cancer death among women and its incidence doubled in the last two decades. Several approaches for the treatment of these cancers have been developed. The axillary lymph node dissection (ALND) leads to numerous morbidity complications and is now advantageously replaced by the dissection and the biopsy of the sentinel lymph node. Although this approach has strong advantages, it has its own limitations which are manipulation of radioactive products and possible anaphylactic reactions to the dye. As recently proposed, these limitations could in principle be by-passed if semiconductor nanoparticles (quantum dots or QDs) were used as fluorescent contrast agents for the <it>in vivo </it>imaging of SLN. QDs are fluorescent nanoparticles with unique optical properties like strong resistance to photobleaching, size dependent emission wavelength, large molar extinction coefficient, and good quantum yield.</p> <p>Methods</p> <p>CdSe/ZnS core/shell QDs emitting around 655 nm were used in our studies. 20 μL of 1 μM (20 pmol) QDs solution were injected subcutaneously in the anterior paw of healthy nude mice and the axillary lymph node (ALN) was identified visually after injection of a blue dye. <it>In vivo </it>fluorescence spectroscopy was performed on ALN before the mice were sacrificed at 5, 15, 30, 60 min and 24 h after QDs injection. ALN and all other organs were removed, cryosectioned and observed in fluorescence microscopy. The organs were then chemically made soluble to extract QDs. Plasmatic, urinary and fecal fluorescence levels were measured.</p> <p>Results</p> <p>QDs were detected in ALN as soon as 5 min and up to 24 h after the injection. The maximum amount of QDs in the ALN was detected 60 min after the injection and corresponds to 2.42% of the injected dose. Most of the injected QDs remained at the injection site. No QDs were detected in other tissues, plasma, urine and feces.</p> <p>Conclusion</p> <p>Effective and rapid (few minutes) detection of sentinel lymph node using fluorescent imaging of quantum dots was demonstrated. This work was done using very low doses of injected QDs and the detection was done using a minimally invasive method.</p

Etude des mécanismes du photoblanchiment de la 5,10,15,20-tetrakis(m-hydroxyphenyl)bactériochlorine, en solution, in vitro et in vivo.

Photodynamic therapy (PDT) has been developed as a treatment modality for a number of malignant and non-malignant disorders. PDT treatment is based on the presence of a drug with photosensitising and tumour localizing properties combined with visible light and oxygen. Accurate dosimetry is necessary to ensure complete treatment and to allow for consistent and reproducible patient outcomes. One of the key element which needs to be considered in dosimetry is photobleaching since it decrease the photosensitiser concentration during the treatment. It seems therefore important to understand the photobleaching mechanisms to adapt the photodynamic dose and receive the optimal treatment.The photobleaching quantum yield in solution supplemented with proteins is 5.7 x 10-4, the aggregated forms of the photosensitiser bleach slower than the monomerised forms. Under light exposure the m-THPBC is transformed in m-THPC, the phototransformation yield is influenced by the aggregation state of the molecule. Some other photoproducts such as dihydroxy m-THPBC, di-hydroxy m-THPC, dipyrin derivatives were observed. Singlet oxygen was found to be responsible of the photobleaching of both m-THPBC and m-THPC. In vitro, the m-THPBC LD50 is 0.7 J cm-2, and the photobleaching 3 to 5 times faster than m-THPC. Fluorescence microscopy study exhibits a discrepancy in the photosensitisers localisation, m-THPC is localised is the endoplasmic reticulum and m-THPBC accumulates in mitochondria. In vivo m-THPBC photobleaching is 4 to 10 times faster than m-THPC, with a good tumour accumulation. Taking as a whole these observations are particularly attractive in terms of therapeutic ratio and selectivity of the treatment and skin photosensitivity.La thérapie photodynamique (PDT) est une modalité de traitement des petites tumeurs localisées accessibles à la lumière. Son principe repose sur l'action conjuguée d'un photosensibilisant, de la lumière et de l'oxygène.Une dosimétrie correcte est nécessaire pour assurer le traitement complet et des résultats reproductibles. Un élément clé de la dosimétrie à prendre en compte est le photoblanchiment, étant donné qu'il diminue la concentration du photosensibilisant au cours du traitement. Il est donc indispensable d'appréhender les mécanismes du photoblanchiment pour maîtriser au mieux le traitement.Le rendement quantique de photoblanchiment de la m-THPBC en solution avec des protéines est de 5.7 x 10-4, les formes agrégées de photosensibilisants photoblanchissent plus lentement que les formes monomérisées. La m-THPBC se transforme sous l'effet de la lumière en m-THPC, ce rendement de phototransformation est influencé par l'état d'agrégation de la molécule. D'autres photoproduits tels que la m-THPBC di-hydroxylée et la m-THPC dihydroxylée ainsi que des dérivés dipyrines ont été observés. L'espèce responsable du photoblanchiment a été identifiée comme étant l'oxygène singulet. In vitro, la LD50 de la m-THPBC est 0.7 J cm-2. Le photoblanchiment est 3 à 5 fois plus sensible que celui de la m-THPC. L'étude de la localisation intra-cellulaire des photosensibilisants a montré une différence, la m-THPC s'accumulant dans le réticulum endoplasmique alors que la m-THPBC se localise dans les mitochondries. In vivo, la m-THPBC possède un photoblanchiment 4 à 10 fois plus élevé que la m-THPC, ainsi qu'une bonne accumulation tumorale. Ces résultats in vitro et in vivo sont particulièrement intéressants en terme de ratio thérapeutique, de sélectivité du traitement et de photosensibilité cutanée

Study of the photobleaching mechanisms of the 5,10,15,20-tetrakis (m-hydroxyphenyl) bacteriochlorin (m-THPBC), in solution , in vitro and in vivo

La thérapie pbotodynamique (PDT est une modalité de traitement des petites tumeurs localisées accessibles à la lumière. Son principe repose sur l'action conjuguée d'un photo sensibilisant, de la lumière et de l'oxygène. Une dosimétrie correcte est nécessaire pour assurer le traitement complet et des résultats reproductibles. Un élément clé de la dosimétrie à prendre en compte est le photoblanchiment, étant donné qu'il diminue la concentration du photosensibilisant au cours du traitement. Il est donc indispensabte d'appréhender les mécanismes du photoblanchiment pour maîtriser au mieux le traitement. Le rendement quantique de photoblanchiment de la m-THPBC en solution avec des protéines est de 5.7 X 10-4, les formes agrégées de photosensibilisants photoblanchissent plus lentement que les formes monomérisées. La m-THPBC se transforme sous l'effet de la lumière en m-THPC, ce rendement de phototransformation est influencé par l'état d'agrégation de la molécule. D'autres photoproduits tels que la m-THPBC di-bydroxylée et la m-THPC dibydroxylée ainsi que des dérivés dipyrines ont été observés. L'espèce responsable du photoblanchiment a été identifiée comme étant l'oxygène singulet. ln vitro, la LD50 de la mTHPBC est 0.7 J cm-2. Le photoblanchiment est 3 à 5 fois plus sensible que celui de la m-THPC. L'étude de la localisation intra-cellulaire des photosensibilisants a montré une différence, la m-THPC s'accumulant dans le réticulum endoplasmique alors que la m-THPBC se localise dans les mitochondries. ln vivo, la m-THPBC possède un photoblanchiment 4 à 10 fois plus élevé que la m-THPC, ainsi qu'une bonne accumulation tumorale. Ces résultats in vitro et in vivo sont particulièrement intéressants en terme de ratio thérapeutique, de sélectivité du traitement et de photosensibilité cutanée.Photodynamic therapy (PDT) bas been developed as a treatment modality for a number of malignant and non-malignant disorders. PDT treatment is based on the presence of a drug with photosensitising and tumour localizing properties combined with visible light and oxygen. Accurate dosimetry is necessary to ensure complete treatment and to allow for consistent and reproducible patient outcomes. One of the key element which needs to be considered in dosimetry is photobleaching since it decrease the photosensitiser concentration during the treatment. It seems therefore important to understand the photobleaching mechanisms to adapt the photodynamic dose and receive the optimal treatment. The photobleaching quantum yield in solution supplemented with proteins is 5.7 x 10-4 the aggregated forms of the photosensitiser bleach slower than the monomerised forms. Under light exposure the m-THPBC is transformed in m-THPC, the phototransformtion yield is influenced by the aggregation state of the molecule. Some other photoproducts such as di-hydroxy m-THPBC, di-hydroxy m- THPC, dipyrin derivatives were observed. Singlet oxygen was found to be responsible of the photobleaching of both m-THPBC and m-THPC. ln vitro, the m-THPBC LD50 is 0.7 J cm-2, and the photobleaching 3 to 5 times faster than m-THPC. Fluorescence microscopy study exhibits il discrepancy in the photosensitisers localisation, m-THPC is localised is the endop1asmic reticulum and m-THPBC accumulates in mitochondria. ln vivo m- THPBC photobleaching is 4 to 10 times faster than m- THPC, with a good tumour accumulation. Taking as a whole these observations are particularly attractive in terms of therapeutic ratio and selectivity or the treatment and skin photosensitivity.NANCY1-SCD Medecine (545472101) / SudocSudocFranceF

Optimization of the composition of liposomal-based hybrid nanoparticles for mTHPC delivery

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Interactions mechanisms of temoporphin liposomal formulations with serum proteins

International audienceMeta-tetra(hydroxyphenyl)chorin (temoporfin, mTHPC) is a non-polar photosensitizer used in photodynamic therapy. To improve its solubility and pharmacokinetic properties, liposomes were proposed as drug carriers. Liposomes offer the advantage of drug monomerization and increase in photosensitizer photoactivity, as well as an enhanced permeability and retention (EPR) effect. Recently, we proposed novel liposomal formulation based on the encapsulation of inclusion complexes with mTHPC in the inner aqueous core of liposomes, namely drug-in-cyclodextrin-in-liposome (DCL). However, the stability of liposomal formulation in terms of solute release and destruction of vesicle structure presents a challenge for successful application of lipid carriers. The problem of stability was extensively studied in different in vitro and in preclinical models. The aim of the present study was to evaluate the interaction and binding specificity of mTHPC liposomal formula-tions to human serum proteins by means of gel-exclusion chromatography technique. We demonstrated the release of mTHPC from liposomal vesicles after incubation with serum. Compared with conventional liposomes DCL appeared to be more stable releasing less mTHPC to the serum proteins. The obtained data suggested that application of DCLs can be successfully applied in mTHPC-PDT. This study was supported by French “Ligue National contre le Cancer”, Belarussian Republican Foundation for Fundamental Research (grant М17МС-028) and the Ministry of Education of the Republic of Belarus. The authors thank biolitec research GmbH (Jena, Germany) for providing mTHPC

Optimization of temoporfin biodistribution by cyclodextrins-based nanostructures

International audienceTemoporfin (meta-tetrakis(3-hydroxyphenyl)chlorin, mTHPC) is one of the most potent clinically approved photosensitizer (PS) for the photodynamic therapy (PDT) of head and neck cancers. mTHPC molecules are highly hydrophobic and are prone to strong aggregation in biological media, resulting in decreased photodynamic efficacy, moderate selectivity and prolonged skin photosensitivity. Various attempts are being made to use special drug delivery forms for mTHPC introduction in order to prevent aggregation and improve pharmacokinetic properties of the PS. Cyclic oligosaccharides such as β-cyclodextrins (β-CDs) are also promising delivery systems for different nonpolar drugs including aryl-substituted porphyrins. β-CDs readily interact with mTHPC incorporating side groups of drug molecule in the inner hydrophobic cavity. The formation of inclusion complexes increases mTHPC solubilization and recovers its photophysical properties. According to our data, β-CDs significantly modify mTHPC in vitro and in vivo biodistribution in particular inhibiting mTHPC aggregation and accelerating PS transportation to target tissue. We have obtained convincing evidence that the β-CDs strongly effect on mTHPC transport mechanism in blood and solid tissues and accelerate its molecules transfer among the various serum proteins and cells. Additional possibilities in PDT with mTHPC are related to the use of β-CDs-based nanoscale structures. Encapsulation of CD/PS inclusion complex into liposomes (drug-in-cyclodextrin-in-liposome, DCL) allows significantly increase entrapment of hydrophobic PS in the aqueous core of liposomes. Application of DCL delays the dissociation of drug-CD complexes, avoid rapid drug release and, as a result, improve the pharmacokinetics of the PSs in vivo. This work was supported by Belarusian Republican Foundation for Fundamental Research (BRFFR) (grant numbers M17MC-028, Б17-106)

Cyclodextrin-based photoactive liposomal nanoparticles for tumor targeting

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Hybrid liposomes for temoporfin delivery to the tumor tissue

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Current state of the nanoscale delivery systems for temoporfin-based photodynamic therapy: Advanced delivery strategies

International audienceEnthusiasm for photodynamic therapy (PDT) as a promising technique to eradicate various cancers has increased exponentially in recent decades. The majority of clinically approved photosensitizers are hydrophobic in nature, thus, the effective delivery of photosensitizers at the targeted site is the main hurdle associated with PDT. Temoporfin (mTHPC, medicinal product name: Foscan®), is one of the most potent clinically approved photosensitizers, is not an exception. Successful temoporfin-PDT requires nanoscale delivery systems for selective delivery of photosensitizer. Over the last 25 years, the number of papers on nanoplatforms developed for mTHPC delivery such as conjugates, host-guest inclusion complexes, lipid-and polymer-based nanoparticles and carbon nanotubes is burgeoning. However, none of them appeared to be “ultimate”. The present review offers the description of different challenges and achievements in nanoparticle-based mTHPC delivery focusing on the synergetic combination of various nano-platforms to improve temoporfin delivery at all stages of biodistribution. Furthermore, the association of different nanoparticles in one nanoplatform might be considered as an advanced strategy allowing the combination of several treatment modalities