Long-term neuroprotection and neurorestoration by glial cell-derived neurotrophic factor microspheres for the treatment of Parkinson's disease.

BACKGROUND: Glial cell-derived neurotrophic factor is a survival factor for dopaminergic neurons and a promising candidate for the treatment of Parkinson's disease. However, the delivery issue of the protein to the brain still remains unsolved. Our aim was to investigate the effect of long-term delivery of encapsulated glial cell-derived neurotrophic factor within microspheres. METHODS: A single dose of microspheres containing 2.5 µg of glial cell-derived neurotrophic factor was implanted intrastriatally in animals 2 weeks after a 6-hydroxydopamine lesion. RESULTS: The amphetamine test showed a complete behavioral recovery after 16 weeks of treatment, which was maintained until the end of the study (week 30). This effect was accompanied by an increase in dopaminergic striatal terminals and neuroprotection of dopaminergic neurons. CONCLUSIONS: The main achievement was the long-term neurorestoration in parkinsonian animals induced by encapsulated glial cell-derived neurotrophic factor, suggesting that microspheres may be considered as a means to deliver glial cell-derived neurotrophic factor for Parkinson's disease treatment.

Improving the genistein oral bioavailability via its formulation into the metal-organic framework MIL-100(Fe).

Despite the interesting chemopreventive, antioxidant and antiangiogenic effects of the natural bioflavonoid genistein (GEN), its low aqueous solubility and bioavailability make it necessary to administer it using a suitable drug carrier system. Nanometric porous metal-organic frameworks (nanoMOFs) are appealing systems for drug delivery. Particularly, mesoporous MIL-100(Fe) possesses a variety of interesting features related to its composition and structure, which make it an excellent candidate to be used as a drug nanocarrier (highly porous, biocompatible, can be synthesized as homogenous and stable nanoparticles (NPs), etc.). In this study, GEN was entrapped via simple impregnation in MIL-100 NPs achieving remarkable drug loading (27.1 wt%). A combination of experimental and computing techniques was used to achieve a deep understanding of the encapsulation of GEN in MIL-100 nanoMOF. Subsequently, GEN delivery studies were carried out under simulated physiological conditions, showing on the whole a sustained GEN release for 3 days. Initial pharmacokinetic and biodistribution studies were also carried out upon the oral administration of the GEN@MIL-100 NPs in a mouse model, evidencing a higher bioavailability and showing that this oral nanoformulation appears to be very promising. To the best of our knowledge, the GEN-loaded MIL-100 will be the first antitumor oral formulation based on nanoMOFs studied in vivo, and paves the way to the efficient delivery of nontoxic antitumorals via a convenient oral route.

Micro- and nanotechnology approaches to improve Parkinson's disease therapy.

Current therapies for Parkinson's disease are symptomatic and unable to regenerate the brain tissue. In recent years, the therapeutic potential of a wide variety of neuroprotective and neuroregenerative molecules such as neurotrophic factors, antioxidants and RNA-based therapeutics has been explored. However, drug delivery to the brain is still a challenge and the therapeutic efficacy of many drugs is limited. In the last decade, micro- and nanoparticles have proved to be powerful tools for the administration of these molecules to the brain, enabling the development of new strategies against Parkinson's disease. The list of encapsulated drugs and the nature of the particles used is long, and numerous studies have been carried out supporting their efficacy in treating this pathology. This review aims to give an overview of the latest advances and emerging frontiers in micro- and nanomedical approaches for repairing dopaminergic neurons. Special emphasis will be placed on offering a new perspective to link these advances with the most relevant clinical trials and with the real possibility of transferring micro- and nanoformulations to industrial scale-up processes. This review is intended as a contribution towards facing the challenges that still exist in the clinical translation of micro- and nanotechnologies to administer therapeutic agents in Parkinson's disease.

Biodegradable gentamicin delivery systems for parenteral use for the treatment of intracellular bacterial infections.

Gentamicin is an aminoglycoside with a wide spectrum of antibacterial activity. However, as a highly water-soluble drug, it penetrates cells poorly. This constitutes a particularly important drawback for treating intracellular bacterial infections. This major hurdle may be solved by the use of vectors to deliver and target bioactive agents to the intracellular sites of infection. Thus, in the case of antimicrobials, drug delivery systems may help to increase their therapeutic index in intracellular locations. The development and evolution of pharmaceutical forms of gentamicin for the parenteral treatment of intracellular pathogens is reviewed in this paper.

Transplantation of adipose-derived stem cells combined with neuregulin-microparticles promotes efficient cardiac repair in a rat myocardial infarction model.

Tissue engineering is a promising strategy to promote heart regeneration after a myocardial infarction (MI). In this study, we investigated the reparative potential of a system that combines adipose-derived stem cells (ADSCs) with microparticles (MPs) loaded with neuregulin (NRG), named ADSC-NRG-MPs, on a rat MI model. First, cells were attached to the surface of MPs encapsulating NRG and coated with a 1:1 mixture of collagen and poly-d-lysine. One week after in vivo administration, the system favored the shift of macrophage expression from a pro-inflammatory to a regenerative phenotype. At long-term, the adhesion of ADSCs to MPs resulted in an increased cell engraftment, with cells being detectable in the tissue up to three months. In consonance, better tissue repair was observed in the animals treated with cells attached to MPs, which presented thicker left ventricles than the animals treated with ADSCs alone. Moreover, the presence of NRG in the system promoted a more complete regeneration, reducing the infarct size and stimulating cardiomyocyte proliferation. Regarding vasculogenesis, the presence of ADSCs and NRG-MPs alone stimulated vessel formation when compared to the control group, but the combination of both induced the largest vasculogenic effect, promoting the formation of both arterioles and capillaries. Importantly, only when ADSCs were administered adhered to MPs, they were incorporated into newly formed vessels. Collectively, these findings demonstrate that the combination of ADSCs, MPs and NRG favored a synergy for inducing a greater and more complete improvement in heart regeneration and provided strong evidence to move forward with preclinical studies with this strategy.

Chemical and biological factors in the control of Brucella and brucellosis.

Brucellosis is a highly contagious bacterial zoonosis that affects millions of people worldwide. Brucella is highly infectious, especially when aerosolized. The infection induces severe protracted diseases, which are both debilitating and incapacitating, hence, Brucella melitensis has been considered a potential biological warfare agent. In the battle against Brucella, it is crucial to know its chemical-structure and biochemistry-metabolic characteristics. It is well known that Brucella, as well as many other intracellular bacterial pathogens, has evolved to survive and even proliferate within monocytes and macrophages cells. Depending on the route of entry (complement, Fc, lectin or fibronectin receptors), the fate of the bacteria will vary; it may even segregate from the endocytic route towards the endoplasmic reticulum. This intracellular "non regular" behaviour of Brucella makes treatment difficult. Most antibiotics, although effective in vitro, do not actively pass through cellular membranes, or, once inside, may not reach the discrete intracellular niche where the bacteria is hidden. Therefore, complete eradication of the microorganisms is difficult to achieve, and the incidence of relapses is rather high. Taking these data into consideration, this review will evaluate the past, current and new trends in the control of brucellosis, paying special attention to the drug delivery systems as potential vectors for targeting these intracellular sites where the organisms are located.

Brain delivery of microencapsulated GDNF induces functional and structural recovery in parkinsonian monkeys.

Glial cell line-derived neurotrophic factor (GDNF) remains the most potent neurotrophic factor for dopamine neurons. Despite its potential as treatment for Parkinson's disease (PD), its clinical application has been hampered by safety and efficacy concerns associated with GDNF's short in vivo half-life and with significant brain delivery obstacles. Drug formulation systems such as microparticles (MPs) may overcome these issues providing protein protection from degradation and sustained drug release over time. We therefore sought to evaluate the efficacy and safety of GDNF delivered via injectable biodegradable MPs in a clinically relevant model of PD and to investigate the mechanism contributing to their beneficial effects. MPs were injected unilaterally into the putamen of parkinsonian monkeys with severe nigrostriatal degeneration. Notably, a single administration of the microencapsulated neurotrophic factor achieved sustained GDNF levels in the brain, providing motor improvement and dopaminergic function restoration. This was reflected by a bilateral increase in the density of striatal dopaminergic neurons 9 months after treatment. Moreover, GDNF was retrogradely transported to the substantia nigra increasing bilaterally the number of dopaminergic and total neurons, regardless of the severe degeneration. GDNF-MP injection within the putamen elicited no adverse effects such as immunogenicity, cerebellar degeneration or weight loss. MPs are therefore a safe, efficient vehicle for sustained protein delivery to the brain, supporting the therapeutic benefit of GDNF when encapsulated within MPs for brain repair. Overall, these findings constitute important groundwork for GDNF-MP clinical development.

Catheter-based Intramyocardial Injection of FGF1 or NRG1-loaded MPs Improves Cardiac Function in a Preclinical Model of Ischemia-Reperfusion.

Cardiovascular protein therapeutics such as neuregulin (NRG1) and acidic-fibroblast growth factor (FGF1) requires new formulation strategies that allow for sustained bioavailability of the drug in the infarcted myocardium. However, there is no FDA-approved injectable protein delivery platform due to translational concerns about biomaterial administration through cardiac catheters. We therefore sought to evaluate the efficacy of percutaneous intramyocardial injection of poly(lactic-co-glycolic acid) microparticles (MPs) loaded with NRG1 and FGF1 using the NOGA MYOSTAR injection catheter in a porcine model of ischemia-reperfusion. NRG1- and FGF1-loaded MPs were prepared using a multiple emulsion solvent-evaporation technique. Infarcted pigs were treated one week after ischemia-reperfusion with MPs containing NRG1, FGF1 or non-loaded MPs delivered via clinically-translatable percutaneous transendocardial-injection. Three months post-treatment, echocardiography indicated a significant improvement in systolic and diastolic cardiac function. Moreover, improvement in bipolar voltage and decrease in transmural infarct progression was demonstrated by electromechanical NOGA-mapping. Functional benefit was associated with an increase in myocardial vascularization and remodeling. These findings in a large animal model of ischemia-reperfusion demonstrate the feasibility and efficacy of using MPs as a delivery system for growth factors and provide strong evidence to move forward with clinical studies using therapeutic proteins combined with catheter-compatible biomaterials.

Biocompatible polymer-metal-organic framework composite patches for cutaneous administration of cosmetic molecules.

Despite increasing interest in metal-organic frameworks (MOFs) in the biomedical field, developing specific formulations suitable for different administration routes is still a main challenge. Here, we propose a simple, fast and bio-friendly press-molding method for the preparation of cutaneous patches based on composites made from the drug nanocarrier MIL-100(Fe) and biopolymers. The physicochemical properties of the patches (structure, hydration, bioadhesive and swelling properties), as well as their encapsulation and release capabilities (both in ex vitro and ex vivo models), were evaluated using active ingredients such as the challenging cosmetic liporeductor, caffeine, and the model analgesic and anti-inflammatory drug, ibuprofen. In particular, very high caffeine loadings were entrapped within these cutaneous devices with progressive releases under simulated cutaneous physiological conditions as a consequence of the swelling of the hydrophilic patches. Despite the absence of any cutaneous bioadhesive character, these patches provided progressive and suitable permeation of their cosmetic cargo through the skin, interestingly reaching the targeted adipose tissue. This makes these cosmetic-containing composite MOF-based patches promising candidates for new cutaneous devices in cosmetic applications.

Polymeric particulates to improve oral bioavailability of peptide drugs.

Oral administration remains the most convenient way of delivering drugs. Recent advances in biotechnology have produced highly potent new molecules such as peptides, proteins and nucleic acids. Due to their sensitivity to chemical and enzymatic hydrolysis as well as a poor cellular uptake, their oral bioavailability remains very low. Despite sophisticated new delivery systems, the development of a satisfactory oral formulation remains a challenge. Among the possible strategies to improve the absorption of drugs, micro- and nanoparticles represent an exciting approach to enhance the uptake and transport of orally administered molecules. Increasing attention has been paid to their potential use as carriers for peptide drugs for oral administration. This article reviews the most common manufacturing methods for polymeric particles and the physiology of particle absorption from the gastrointestinal (GI) tract. In a second part, the use of polymeric particulate systems to improve the oral absorption of insulin is discussed.

Lipid nanoparticles for cyclosporine A administration: development, characterization, and in vitro evaluation of their immunosuppression activity.

Cyclosporine A (CsA) is an immunosuppressant commonly used in transplantation for prevention of organ rejection as well as in the treatment of several autoimmune disorders. Although commercial formulations are available, they have some stability, bioavailability, and toxicity related problems. Some of these issues are associated with the drug or excipients and others with the dosage forms. With the aim of overcoming these drawbacks, lipid nanoparticles (LN) have been proposed as an alternative, since excipients are biocompatible and also a large amount of surfactants and organic solvents can be avoided. CsA was successfully incorporated into LN using the method of hot homogenization followed by ultrasonication. Three different formulations were optimized for CsA oral administration, using different surfactants: Tween(®) 80, phosphatidylcholine, taurocholate and Pluronic(®) F127 (either alone or mixtures). Freshly prepared Precirol nanoparticles showed mean sizes with a narrow size distribution ranging from 121 to 202 nm, and after freeze-drying were between 163 and 270 nm, depending on the stabilizer used. Surface charge was negative in all LN developed. High CsA entrapment efficiency of approximately 100% was achieved. Transmission electron microscopy was used to study the morphology of the optimized LN. Also, the crystallinity of the nanoparticles was studied by X-ray powder diffraction and differential scanning calorimetry. The presence of the drug in LN surfaces was confirmed by X-ray photoelectron spectroscopy. The CsA LN developed preserved their physicochemical properties for 3 months when stored at 4°C. Moreover, when the stabilizer system was composed of two surfactants, the LN formulations were also stable at room temperature. Finally, the new CsA formulations showed in vitro dose-dependent immuno-suppressive effects caused by the inhibition of IL-2 levels secreted from stimulated Jurkat cells. The findings obtained in this paper suggest that new lipid nanosystems are a good alternative to produce physicochemically stable CsA formulations for oral administration.

Efficacy of edelfosine lipid nanoparticles in breast cancer cells.

Breast cancer is a heterogeneous group of neoplasms predominantly originating in the terminal duct lobular units. It represents the leading cause of cancer death in women and the survival frequencies for patients at advanced stages of the disease remain low. New treatment options need to be researched to improve these rates. The anti-tumor ether lipid edelfosine (ET) is the prototype of a novel generation of promising anticancer drugs. However, it presents several drawbacks for its use in cancer therapy, including gastrointestinal and hemolytic toxicity and low oral bioavailability. To overcome these obstacles, ET was encapsulated in Precirol ATO 5 lipid nanoparticles (ET-LN), and its anti-tumor potential was in vitro tested in breast cancer. The formulated ET-LN were more effective in inhibiting cell proliferation and notably decreased cell viability, showing that the cytotoxic effect of ET was considerably enhanced when ET was encapsulated. In addition, ET and ET-LN were able to promote cell cycle arrest at G1 phase. Moreover, although both treatments provoked an apoptotic effect in a time-dependent manner, such anti-tumor effects were noticeably improved with ET-LN treatment. Therefore, our results indicate that encapsulating ET in LN played an essential role in improving the efficacy of the drug.