Bernard Ucakar

Dual anticancer drug/superparamagnetic iron oxide-loaded PLGA-based nanoparticles for cancer therapy and magnetic resonance imaging

We developed dual paclitaxel (PTX)/superparamagnetic iron oxide (SPIO)-loaded PLGA-based nanoparticles for a theranostic purpose. Nanoparticles presented a spherical morphology and a size of 240 nm. The PTX and iron loading were 1.84 ± 0.4 and 10.4 ± 1.93 mg/100 mg respectively. Relaxometry studies and phantom MRI demonstrated their efficacy as T₂ contrast agent. Significant cellular uptake by CT26 cells of nanoparticles was shown by Prussian blue staining and fluorescent microscopy. While SPIO did not show any toxicity in CT-26 cells, PTX-loaded nanoparticles had a cytotoxic activity. PTX-loaded nanoparticle (5 mg/kg) with or without co-encapulated SPIO induced in vivo a regrowth delay of CT26 tumors. Together these multifunctional nanoparticles may be considered as future nanomedicine for simultaneous molecular imaging, drug delivery and real-time monitoring of therapeutic response.

3D systems delivering VEGF to promote angiogenesis for tissue engineering.

In most cases, vascularization is the first requirement to achieve tissue regeneration. The delivery from implants of angiogenic factors, like VEGF, has been widely investigated for establishing a vascular network within the developing tissue. In this report, we investigated if encapsulation of VEGF in nanoparticles could enhance angiogenesis in vivo as compared to free VEGF when incorporated into two different types of 3D matrices: Matrigel™ hydrogels and PLGA scaffolds. Negatively charged nanoparticles encapsulating VEGF were obtained with a high efficiency by complex formation with dextran sulfate and coacervation by chitosan. After 2weeks, encapsulation reduced VEGF release from hydrogels from 30% to 1% and increased VEGF release from scaffolds from 20% to 30% in comparison with free VEGF. VEGF encapsulation consistently improved angiogenesis in vivo with both type of 3D matrices: up to 7.5- to 3.5-times more endothelial and red blood cells were observed, respectively, into hydrogels and scaffolds. Hence, encapsulation in nanoparticles enhanced VEGF efficiency by protection and controlled release from 3D implants. Encapsulation and incorporation of VEGF into 3D implants that, in addition to sustaining cell infiltration and organization, will stimulate blood vessel are a promising approach for tissue regeneration engineering.

Comparison of active, passive and magnetic targeting to tumors of multifunctional paclitaxel/SPIO-loaded nanoparticles for tumor imaging and therapy

Multifunctional nanoparticles combining therapy and imaging have the potential to improve cancer treatment by allowing personalized therapy. Herein, we aimed to compare in vivo different strategies in terms of targeting capabilities: (1) passive targeting via the EPR effect, (2) active targeting of αvβ3 integrin via RGD grafting, (3) magnetic targeting via a magnet placed on the tumor and (4) the combination of magnetic targeting and active targeting of αvβ3 integrin. For a translational approach, PLGA-based nanoparticles loaded with paclitaxel and superparamagnetic iron oxides were used. Electron Spin Resonance spectroscopy and Magnetic Resonance Imaging (MRI) were used to both quantify and visualize the accumulation of multifunctional nanoparticles into the tumors. We demonstrate that compared to untargeted or single targeted nanoparticles, the combination of both active strategy and magnetic targeting drastically enhanced (i) nanoparticle accumulation into the tumor tissue with an 8-fold increase compared to passive targeting (1.12% and 0.135% of the injected dose, respectively), (ii) contrast in MRI (imaging purpose) and (iii) anti-cancer efficacy with a median survival time of 22 days compared to 13 for the passive targeting (therapeutic purpose). Double targeting of nanoparticles to tumors by different mechanisms could be a promising translational approach for the management of therapeutic treatment and personalized therapy.

Combined effect of PLGA and curcumin on wound healing activity

Wound healing is a complex process involving many interdependent and overlapping sequences of physiological actions. The application of exogenous lactate released from poly (lactic-co-glycolic acid) (PLGA) polymer accelerated angiogenesis and wound healing processes. Curcumin is a well-known topical wound healing agent for both normal and diabetic-impaired wounds. Hence, we hypothesized that the PLGA nanoparticles encapsulating curcumin could much potentially accelerate the wound healing. In a full thickness excisional wound healing mouse model, PLGA-curcumin nanoparticles showed a twofold higher wound healing activity compared to that of PLGA or curcumin. Histology and RT-PCR studies confirmed that PLGA-curcumin nanoparticles exhibited higher re-epithelialization, granulation tissue formation and anti-inflammatory potential. PLGA nanoparticles offered various benefits for the encapsulated curcumin like protection from light degradation, enhanced water solubility and showed a sustained release of curcumin over a period of 8 days. In conclusion, we demonstrated the additive effect of lactic acid from PLGA and encapsulated curcumin for the active healing of wounds.

pH-sensitive nanoparticles for colonic delivery of curcumin in inflammatory bowel disease

Nano-scaled particles have been found to preferentially accumulate in inflamed regions. Local delivery of anti-inflammatory drugs loaded in nanoparticles to the inflamed colonic site is of great interest for inflammatory bowel disease (IBD) treatment. Curcumin (CC) is an anti-inflammatory local agent, which presents poor ADME properties. Hence, we evaluated, both in vitro and in vivo, the local delivery of CC using pH-sensitive polymeric nanoparticles (NPs) combining both poly(lactide-co-glycolide) acid (PLGA) and a polymethacrylate polymer (Eudragit(®) S100). CC-NPs significantly enhanced CC permeation across Caco-2 cell monolayers when compared to CC in suspension. CC-NPs significantly reduced TNF-α secretion by LPS-activated macrophages (J774 cells). In vivo, CC-NPs significantly decreased neutrophil infiltration and TNF-α secretion while maintaining the colonic structure similar to the control group in a murine DSS-induced colitis model. Our results support the use of nanoparticles made of PLGA and Eudragit(®) S100 combination for CC delivery in IBD treatment.

Injectable alginate hydrogel loaded with GDNF promotes functional recovery in a hemisection model of spinal cord injury

We hypothesized that local delivery of GDNF in spinal cord lesion via an injectable alginate hydrogel gelifying in situ would support spinal cord plasticity and functional recovery. The GDNF release from the hydrogel was slowed by GDNF encapsulation in microspheres compared to non-formulated GDNF (free GDNF). When injected in a rat spinal cord hemisection model, more neurofilaments were observed in the lesion when the rats were treated with free GDNF-loaded hydrogels. More growing neurites were detected in the tissues surrounding the lesion when the animals were treated with GDNF microsphere-loaded hydrogels. Intense GFAP (astrocytes), low βIII tubulin (neural cells) and RECA-1 (endothelial cells) stainings were observed for non-treated lesions while GDNF-treated spinal cords presented less GFAP staining and more endothelial and nerve fiber infiltration in the lesion site. The animals treated with free GDNF-loaded hydrogel presented superior functional recovery compared with the animals treated with the GDNF microsphere-loaded hydrogels and non-treated animals.

Transdermal Delivery of Timolol and Atenolol Using Electroporation and Iontophoresis in Combination: A Mechanistic Approach

AbstractPurpose. The purpose of this work was to study the effect of electroporation on iontophoretic transport of two β-blockers, timolol (lipophilic) and atenolol (hydrophilic), and to have a better understanding of the mechanism of combination. Methods. The transdermal delivery of these β-blockers through human stratum corneum was studied in three-compartment diffusion cells. The transport of mannitol was evaluated to assess the electroosmotic flow. Results. The iontophoretic transport of timolol was decreased by electroporation because the high accumulation of the lipophilic cation timolol in the stratum corneum resulted in a decrease of electroosmosis. In contrast, electroosmosis was not affected by atenolol, and the iontophoretic transport of atenolol was increased by electroporation. Conclusions. Using two different β-blockers, we showed that lipophilicity and positive charges affect the electrotransport of drugs. Understanding the effect of the physicochemical properties of the drug, as well as the electrical parameters, is thus essential for the optimization of transdermal drug delivery by a combination of electroporation and iontophoresis.

Active and passive tumor targeting of a novel poorly soluble cyclin dependent kinase inhibitor, JNJ-7706621.

The anti-cancer cyclin dependent kinase (CDK) inhibitors are poorly soluble drugs. The aims of this work were (i) to formulate a novel CDK inhibitor, JNJ-7706621, in polymeric micelles and nanoparticles, (ii) to compare passive and active targeting on tumor growth and (iii) to evaluate the potential synergy of JNJ-7706621 with Paclitaxel. Therefore, JNJ-7706621 was encapsulated in self-assembling diblock copolymers made up of epsilon-caprolactone (CL) and trimethylene carbonate (TMC) (PEG-p-(CL-co-TMC)) polymeric micelles and in (poly(lactide-co-glycolide)) (PLGA)-based PEGylated nanoparticles (passive targeting) as well as in RGD-grafted nanoparticles (active targeting). In vivo, the transplantable liver tumor growth was more decreased by active targeting with RGD-grafted nanoparticles than by passive targeting with micelles or ungrafted nanoparticles. Moreover, a synergy between JNJ-7706621 and Paclitaxel was demonstrated. Therefore, active targeting of JNJ-7706621-loaded nanocarriers may be considered as an effective anti-cancer drug delivery system for cancer chemotherapy, particularly in combination with Paclitaxel.

Lauroyl-gemcitabine-loaded lipid nanocapsule hydrogel for the treatment of glioblastoma

The local delivery of chemotherapeutic agents is a very promising strategy for the treatment of glioblastoma (GBM). Gemcitabine is a chemotherapeutic agent that has a different mechanism of action compared to alkylating agents and shows excellent radio-sensitizing properties. So, we developed an injectable gel-like nanodelivery system consisting in lipid nanocapsules loaded with anticancer prodrug lauroyl-gemcitabine (GemC12-LNC) in order to obtain a sustained and local delivery of this drug in the brain. In this study, the GemC12-LNC has been formulated and characterized and the viscoelastic properties of the hydrogel were evaluated after extrusion from 30G needles. This system showed a sustained and prolonged in vitro release of the drug over one month. GemC12 and the GemC12-LNC have shown increased in vitro cytotoxic activity on U-87 MG glioma cells compared to the parent hydrophilic drug. The GemC12-LNC hydrogel reduced significantly the size of a subcutaneous human GBM tumor model compared to the drug and short-term tolerability studies showed that this system is suitable for local treatment in the brain. In conclusion, this proof-of-concept study demonstrated the feasibility, safety and efficiency of the injectable GemC12-LNC hydrogel for the local treatment of GBM.

Vascular endothelial growth factor‐loaded injectable hydrogel enhances plasticity in the injured spinal cord

We hypothesized that vascular endothelial growth factor (VEGF)-containing hydrogels that gelify in situ after injection into a traumatized spinal cord, could stimulate spinal cord regeneration. Injectable hydrogels composed of 0.5% Pronova UPMVG MVG alginate, supplemented or not with fibrinogen, were used. The addition of fibrinogen to alginate had no effect on cell proliferation in vitro but supported neurite growth ex vivo. When injected into a rat spinal cord in a hemisection model, alginate supplemented with fibrinogen was well tolerated. The release of VEGF that was incorporated into the hydrogel was influenced by the VEGF formulation [encapsulated in microspheres or in nanoparticles or in solution (free)]. A combination of free VEGF and VEGF-loaded nanoparticles was mixed with alginate:fibrinogen and injected into the lesion of the spinal cord. Four weeks post injection, angiogenesis and neurite growth were increased compared to hydrogel alone. The local delivery of VEGF by injectable alginate:fibrinogen-based hydrogel induced some plasticity in the injured spinal cord involving fiber growth into the lesion site.