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1.
Int J Mol Sci ; 22(14)2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34298939

RESUMO

The present study deals with the mathematical modeling of crosslinking kinetics of polymer-phenol conjugates mediated by the Horseradish Peroxidase (HRP)-hydrogen peroxide (H2O2) initiation system. More specifically, a dynamic Monte Carlo (MC) kinetic model is developed to quantify the effects of crosslinking conditions (i.e., polymer concentration, degree of phenol substitution and HRP and H2O2 concentrations) on the gelation onset time; evolution of molecular weight distribution and number and weight average molecular weights of the crosslinkable polymer chains and gel fraction. It is shown that the MC kinetic model can faithfully describe the crosslinking kinetics of a finite sample of crosslinkable polymer chains with time, providing detailed molecular information for the crosslinkable system before and after the gelation point. The MC model is validated using experimental measurements on the crosslinking of a tyramine modified Hyaluronic Acid (HA-Tyr) polymer solution reported in the literature. Based on the rubber elasticity theory and the MC results, the dynamic evolution of hydrogel viscoelastic and molecular properties (i.e., number average molecular weight between crosslinks, Mc, and hydrogel mesh size, ξ) are calculated.


Assuntos
Ácido Hialurônico/química , Tiramina/química , Elasticidade , Peroxidase do Rábano Silvestre/química , Hidrogéis/química , Peróxido de Hidrogênio/química , Cinética , Modelos Teóricos , Método de Monte Carlo , Polímeros/química , Reologia
2.
Polymers (Basel) ; 12(7)2020 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-32708378

RESUMO

Methacrylated hyaluronic acid (MeHA) and chondroitin sulfate (CS)-biofunctionalized MeHA (CS-MeHA), were crosslinked in the presence of a matrix metalloproteinase 7 (MMP7)-sensitive peptide. The synthesized hydrogels were embedded with either human mesenchymal stem cells (hMSCs) or chondrocytes, at low concentrations, and subsequently cultured in a stem cell medium (SCM) or chondrogenic induction medium (CiM). The pivotal role of the synthesized hydrogels in promoting the expression of cartilage-related genes and the formation of neocartilage tissue despite the low concentration of encapsulated cells was assessed. It was found that hMSC-laden MeHA hydrogels cultured in an expansion medium exhibited a significant increase in the expression of chondrogenic markers compared to hMSCs cultured on a tissue culture polystyrene plate (TCPS). This favorable outcome was further enhanced for hMSC-laden CS-MeHA hydrogels, indicating the positive effect of the glycosaminoglycan binding peptide on the differentiation of hMSCs towards a chondrogenic phenotype. However, it was shown that an induction medium is necessary to achieve full span chondrogenesis. Finally, the histological analysis of chondrocyte-laden MeHA hydrogels cultured on an ex vivo osteochondral platform revealed the deposition of glycosaminoglycans (GAGs) and the arrangement of chondrocyte clusters in isogenous groups, which is characteristic of hyaline cartilage morphology.

3.
Brain Sci ; 10(6)2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32486045

RESUMO

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system and is considered to be the leading non-traumatic cause of neurological disability in young adults. Current treatments for MS comprise long-term immunosuppressant drugs and disease-modifying therapies (DMTs) designed to alter its progress with the enhanced risk of severe side effects. The Holy Grail for the treatment of MS is to specifically suppress the disease while at the same time allow the immune system to be functionally active against infectious diseases and malignancy. This could be achieved via the development of immunotherapies designed to specifically suppress immune responses to self-antigens (e.g., myelin antigens). The present study attempts to highlight the various antigen-specific immunotherapies developed so far for the treatment of multiple sclerosis (e.g., vaccination with myelin-derived peptides/proteins, plasmid DNA encoding myelin epitopes, tolerogenic dendritic cells pulsed with encephalitogenic epitopes of myelin proteins, attenuated autologous T cells specific for myelin antigens, T cell receptor peptides, carriers loaded/conjugated with myelin immunodominant peptides, etc), focusing on the outcome of their recent preclinical and clinical evaluation, and to shed light on the mechanisms involved in the immunopathogenesis and treatment of multiple sclerosis.

4.
Front Immunol ; 10: 2749, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31849951

RESUMO

Visceral leishmaniasis (VL) caused by Leishmania donovani and L. infantum is a potentially fatal disease. To date there are no registered vaccines for disease prevention despite the fact that several vaccines are in preclinical development. Thus, new strategies are needed to improve vaccine efficacy based on a better understanding of the mechanisms mediating protective immunity and mechanisms of host immune responses subversion by immunopathogenic components of Leishmania. We found that mice vaccinated with CPA162-189-loaded p8-PLGA nanoparticles, an experimental nanovaccine, induced the differentiation of antigen-specific CD8+ T cells in spleen compared to control mice, characterized by increased dynamics of proliferation and high amounts of IFN-γ production after ex vivo re-stimulation with CPA162-189 antigen. Vaccination with CPA162-189-loaded p8-PLGA nanoparticles resulted in about 80% lower parasite load in spleen and liver at 4 weeks after challenge with L. infantum promastigotes as compared to control mice. However, 16 weeks after infection the parasite load in spleen was comparable in both mouse groups. Decreased protection levels in vaccinated mice were followed by up-regulation of the anti-inflammatory IL-10 production although at lower levels in comparison to control mice. Microarray analysis in spleen tissue at 4 weeks post challenge revealed different immune-related profiles among the two groups. Specifically, vaccinated mice were characterized by similar profile to naïve mice. On the other hand, the transcriptome of the non-vaccinated mice was dominated by increased expression of genes related to interferon type I, granulocyte chemotaxis, and immune cells suppression. This profile was significantly enriched at 16 weeks post challenge, a time-point which is relative to disease establishment, and was common for both groups, further suggesting that type I signaling and granulocyte influx has a significant role in disease establishment, pathogenesis and eventually in decreased vaccine efficacy for stimulating long-term protection. Overall, we put a spotlight on host immune networks during active VL as potential targets to improve and design more effective vaccines against disease.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Cisteína Proteases/imunologia , Leishmania donovani/fisiologia , Leishmania infantum/fisiologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/imunologia , Fígado/imunologia , Nanopartículas/administração & dosagem , Peptídeos/imunologia , Proteínas de Protozoários/imunologia , Animais , Biomarcadores/metabolismo , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Cisteína Proteases/química , Perfilação da Expressão Gênica , Humanos , Tolerância Imunológica , Interferon gama/metabolismo , Fígado/parasitologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Modelos Animais , Nanopartículas/química , Carga Parasitária , Peptídeos/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Proteínas de Protozoários/química
5.
Eur J Pharm Biopharm ; 128: 337-362, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29733950

RESUMO

Central nervous system (CNS) disorders (e.g., multiple sclerosis, Alzheimer's disease, etc.) represent a growing public health issue, primarily due to the increased life expectancy and the aging population. The treatment of such disorders is notably elaborate and requires the delivery of therapeutics to the brain in appropriate amounts to elicit a pharmacological response. However, despite the major advances both in neuroscience and drug delivery research, the administration of drugs to the CNS still remains elusive. It is commonly accepted that effectiveness-related issues arise due to the inability of parenterally administered macromolecules to cross the Blood-Brain Barrier (BBB) in order to access the CNS, thus impeding their successful delivery to brain tissues. As a result, the direct Nose-to-Brain delivery has emerged as a powerful strategy to circumvent the BBB and deliver drugs to the brain. The present review article attempts to highlight the different experimental and computational approaches pursued so far to attain and enhance the direct delivery of therapeutic agents to the brain and shed some light on the underlying mechanisms involved in the pathogenesis and treatment of neurological disorders.


Assuntos
Administração Intranasal/métodos , Encéfalo/metabolismo , Fármacos do Sistema Nervoso Central/administração & dosagem , Doenças do Sistema Nervoso Central/tratamento farmacológico , Portadores de Fármacos/química , Administração Intranasal/instrumentação , Animais , Transporte Biológico , Barreira Hematoencefálica/metabolismo , Encéfalo/irrigação sanguínea , Encéfalo/efeitos dos fármacos , Epitélio/irrigação sanguínea , Epitélio/metabolismo , Humanos , Mucosa Nasal/irrigação sanguínea , Mucosa Nasal/metabolismo , Permeabilidade
6.
Int J Nanomedicine ; 12: 6169-6184, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28883727

RESUMO

Visceral leishmaniasis (VL) persists as a major public health problem, and since the existing chemotherapy is far from satisfactory, development of an effective vaccine emerges as the most appropriate strategy for confronting VL. The development of an effective vaccine relies on the selection of the appropriate antigen and also the right adjuvant and/or delivery vehicle. In the present study, the protective efficacy of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs), which were surface-modified with a TNFα-mimicking eight-amino-acid peptide (p8) and further functionalized by encapsulating soluble Leishmania infantum antigens (sLiAg) and monophosphoryl lipid A (MPLA), a TLR4 ligand, was evaluated against challenge with L. infantum parasites in BALB/c mice. Vaccination with these multifunctionalized PLGA nanoformulations conferred significant protection against parasite infection in vaccinated mice. In particular, vaccination with PLGA-sLiAg-MPLA or p8-PLGA-sLiAg NPs resulted in almost complete elimination of the parasite in the spleen for up to 4 months post-challenge. Parasite burden reduction was accompanied by antigen-specific humoral and cellular immune responses. Specifically, injection with PLGA-sLiAg-MPLA raised exclusively anti-sLiAg IgG1 antibodies post-vaccination, while in p8-PLGA-sLiAg-vaccinated mice, no antibody production was detected. However, 4 months post-challenge, in mice vaccinated with all the multifunctionalized NPs, antibody class switching towards IgG2a subtype was observed. The study of cellular immune responses revealed the increased proliferation capacity of spleen cells against sLiAg, consisting of IFNγ-producing CD4+ and CD8+ T cells. Importantly, the activation of CD8+ T cells was exclusively attributed to vaccination with PLGA NPs surface-modified with the p8 peptide. Moreover, characterization of cytokine production in vaccinated-infected mice revealed that protection was accompanied by significant increase of IFNγ and lower levels of IL-4 and IL-10 in protected mice when compared to control infected group. Conclusively, the above nanoformulations hold promise for future vaccination strategies against VL.


Assuntos
Vacinas contra Leishmaniose/química , Vacinas contra Leishmaniose/farmacologia , Leishmaniose Visceral/prevenção & controle , Nanopartículas/administração & dosagem , Adjuvantes Imunológicos/administração & dosagem , Animais , Antígenos de Protozoários/química , Linfócitos T CD8-Positivos/imunologia , Feminino , Imunidade Celular , Interleucina-10/metabolismo , Interleucina-4/metabolismo , Ácido Láctico/química , Ácido Láctico/imunologia , Leishmania infantum/química , Leishmaniose Visceral/imunologia , Lipídeo A/análogos & derivados , Lipídeo A/química , Lipídeo A/imunologia , Camundongos Endogâmicos BALB C , Nanopartículas/química , Peptídeos/química , Peptídeos/imunologia , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Fator de Necrose Tumoral alfa/química
7.
Front Immunol ; 8: 684, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28659922

RESUMO

Visceral leishmaniasis, caused by Leishmania (L.) donovani and L. infantum protozoan parasites, can provoke overwhelming and protracted epidemics, with high case-fatality rates. An effective vaccine against the disease must rely on the generation of a strong and long-lasting T cell immunity, mediated by CD4+ TH1 and CD8+ T cells. Multi-epitope peptide-based vaccine development is manifesting as the new era of vaccination strategies against Leishmania infection. In this study, we designed chimeric peptides containing HLA-restricted epitopes from three immunogenic L. infantum proteins (cysteine peptidase A, histone H1, and kinetoplastid membrane protein 11), in order to be encapsulated in poly(lactic-co-glycolic) acid nanoparticles with or without the adjuvant monophosphoryl lipid A (MPLA) or surface modification with an octapeptide targeting the tumor necrosis factor receptor II. We aimed to construct differentially functionalized peptide-based nanovaccine candidates and investigate their capacity to stimulate the immunomodulatory properties of dendritic cells (DCs), which are critical regulators of adaptive immunity generated upon vaccination. According to our results, DCs stimulation with the peptide-based nanovaccine candidates with MPLA incorporation or surface modification induced an enhanced maturation profile with prominent IL-12 production, promoting allogeneic T cell proliferation and intracellular production of IFNγ by CD4+ and CD8+ T cell subsets. In addition, DCs stimulated with the peptide-based nanovaccine candidate with MPLA incorporation exhibited a robust transcriptional activation, characterized by upregulated genes indicative of vaccine-driven DCs differentiation toward type 1 phenotype. Immunization of HLA A2.1 transgenic mice with this peptide-based nanovaccine candidate induced peptide-specific IFNγ-producing CD8+ T cells and conferred significant protection against L. infantum infection. Concluding, our findings supported that encapsulation of more than one chimeric multi-epitope peptides from different immunogenic L. infantum proteins in a proper biocompatible delivery system with the right adjuvant is considered as an improved promising approach for the development of a vaccine against VL.

8.
Bioprocess Biosyst Eng ; 40(8): 1247-1260, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28551856

RESUMO

An integrated metabolic-polymerization-macroscopic model, describing the microbial production of polyhydroxybutyrate (PHB) in Azohydromonas lata bacteria, was developed and validated using a comprehensive series of experimental measurements. The model accounted for biomass growth, biopolymer accumulation, carbon and nitrogen sources utilization, oxygen mass transfer and uptake rates and average molecular weights of the accumulated PHB, produced under batch and fed-batch cultivation conditions. Model predictions were in excellent agreement with experimental measurements. The validated model was subsequently utilized to calculate optimal operating conditions and feeding policies for maximizing PHB productivity for desired PHB molecular properties. More specifically, two optimal fed-batch strategies were calculated and experimentally tested: (1) a nitrogen-limited fed-batch policy and (2) a nitrogen sufficient one. The calculated optimal operating policies resulted in a maximum PHB content (94% g/g) in the cultivated bacteria and a biopolymer productivity of 4.2 g/(l h), respectively. Moreover, it was demonstrated that different PHB grades with weight average molecular weights of up to 1513 kg/mol could be produced via the optimal selection of bioprocess operating conditions.


Assuntos
Hidroxibutiratos/química , Biomassa , Biopolímeros , Carbono , Nitrogênio , Poliésteres
9.
Nanomedicine (Lond) ; 12(9): 1057-1074, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28440707

RESUMO

To date, most of the licensed vaccines for mucosal delivery are based on live-attenuated viruses which carry the risk of regaining their pathogenicity. Therefore, the development of efficient nonviral vectors allowing the induction of potent humoral and cell-mediated immunity is regarded as an imperative scientific challenge as well as a commercial breakthrough for the pharma industries. For a successful translation to the clinic, such nanocarriers should protect the antigens from mucosal enzymes, facilitate antigen uptake by microfold cells and allow the copresentation of robust, safe for human use, mucosal adjuvants to antigen-presenting cells. Finally, the developed formulations should exhibit accuracy regarding the administered dose, a major drawback of mucosal vaccines in comparison with parenteral ones.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Membrana Mucosa/imunologia , Nanocápsulas/química , Polímeros/química , Vacinas/administração & dosagem , Animais , Células Apresentadoras de Antígenos/imunologia , Sistemas de Liberação de Medicamentos , Humanos , Imunidade Celular , Imunidade nas Mucosas , Nanomedicina , Nanotecnologia , Vacinação/métodos
10.
PLoS Negl Trop Dis ; 11(1): e0005311, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28114333

RESUMO

BACKGROUND: Through their increased potential to be engaged and processed by dendritic cells (DCs), nanovaccines consisting of Poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with both antigenic moieties and adjuvants are attractive candidates for triggering specific defense mechanisms against intracellular pathogens. The aim of the present study was to evaluate the immunogenicity and prophylactic potential of a rationally designed multi-epitope peptide of Leishmania Cysteine Protease A (CPA160-189) co-encapsulated with Monophosphoryl lipid A (MPLA) in PLGA NPs against L. infantum in BALB/c mice and identify immune markers correlated with protective responses. METHODOLOGY/PRINCIPAL FINDINGS: The DCs phenotypic and functional features exposed to soluble (CPA160-189, CPA160-189+MPLA) or encapsulated in PLGA NPs forms of peptide and adjuvant (PLGA-MPLA, PLGA-CPA160-189, PLGA-CPA160-189+MPLA) was firstly determined using BALB/c bone marrow-derived DCs. The most potent signatures of DCs maturation were obtained with the PLGA-CPA160-189+MPLA NPs. Subcutaneous administration of PLGA-CPA160-189+MPLA NPs in BALB/c mice induced specific anti-CPA160-189 cellular and humoral immune responses characterized by T cells producing high amounts of IL-2, IFN-γ and TNFα and IgG1/IgG2a antibodies. When these mice were challenged with 2x107 stationary phase L. infantum promastigotes, they displayed significant reduced hepatic (48%) and splenic (90%) parasite load at 1 month post-challenge. This protective phenotype was accompanied by a strong spleen lymphoproliferative response and high levels of IL-2, IFN-γ and TNFα versus low IL-4 and IL-10 secretion. Although, at 4 months post-challenge, the reduced parasite load was preserved in the liver (61%), an increase was detected in the spleen (30%), indicating a partial vaccine-induced protection. CONCLUSIONS/SIGNIFICANCE: This study provide a basis for the development of peptide-based nanovaccines against leishmaniasis, since it reveals that vaccination with well-defined Leishmania MHC-restricted epitopes extracted from various immunogenic proteins co-encapsulated with the proper adjuvant or/and phlebotomine fly saliva multi-epitope peptides into clinically compatible PLGA NPs could be a promising approach for the induction of a strong and sustainable protective immunity.


Assuntos
Cisteína Proteases/imunologia , Leishmania infantum/enzimologia , Vacinas contra Leishmaniose/imunologia , Proteínas de Protozoários/imunologia , Vacinas/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Cisteína Proteases/administração & dosagem , Cisteína Proteases/genética , Células Dendríticas/imunologia , Epitopos/administração & dosagem , Epitopos/genética , Epitopos/imunologia , Feminino , Humanos , Interleucina-2/imunologia , Interleucina-4/imunologia , Leishmania infantum/genética , Leishmania infantum/imunologia , Vacinas contra Leishmaniose/administração & dosagem , Vacinas contra Leishmaniose/genética , Camundongos , Camundongos Endogâmicos BALB C , Proteínas de Protozoários/administração & dosagem , Proteínas de Protozoários/genética , Vacinação , Vacinas/administração & dosagem , Vacinas/genética
11.
J Pharm Sci ; 106(3): 850-858, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27964902

RESUMO

Alternate geometries of a commercial dry powder inhaler (DPI, i.e., Turbuhaler; AstraZeneca, London, UK) are proposed based on the simulation results obtained from a fluid and particle dynamic computational model, previously developed by Milenkovic et al. The alternate DPI geometries are constructed by simple alterations to components of the commercial inhaler device leading to smoother flow patterns in regions where significant particle-wall collisions occur. The modified DPIs are investigated under the same conditions of the original studies of Milenkovic et al. for a wide range of inhalation flow rates (i.e., 30-70 L/min). Based on the computational results in terms of total particle deposition and fine particle fraction, the modified DPIs were improved over the original design of the commercial device.


Assuntos
Inaladores de Pó Seco/instrumentação , Inaladores de Pó Seco/normas , Desenho de Equipamento/instrumentação , Desenho de Equipamento/normas , Tecnologia Farmacêutica/instrumentação , Tecnologia Farmacêutica/normas , Administração por Inalação , Tamanho da Partícula
12.
Eur J Pharm Biopharm ; 111: 44-60, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27847276

RESUMO

The oral administration of protein therapeutics is hindered by the multitude of barriers confronted by these molecules along the gastrointestinal tract (i.e., acidic environment, proteolytic degradation, mucosal barrier, etc.). Their unique properties (e.g., high molecular weight, hydrophilicity, charge, etc.) and labile structure are mainly responsible for their instability in the harsh conditions along the gastrointestinal tract (GIT) and dictate the employment of alternative routes for their administration (e.g., parenteral). The association of proteins with colloidal carriers represents an interesting approach to overcome the aforementioned issues. However, certain requirements, such as stability in the GIT, stimuli-responsiveness, protection of the encapsulated biomolecule from enzymatic degradation and permeability of the mucosa, have to be met in order to efficiently deliver the sensitive payload to the intended site of action, thus resulting in enhanced bioavailability. The formation of colloidal polyelectrolyte complexes (PECs) seems to be a promising strategy towards this direction, and the present review aims to provide an insight into PECs (e.g., preparation methods, characteristics) along with their advantages and drawbacks as drug delivery vehicles for the oral administration of protein-based therapeutics.


Assuntos
Coloides/química , Portadores de Fármacos/química , Mucosa Gástrica/metabolismo , Trato Gastrointestinal/imunologia , Polieletrólitos/química , Proteínas/administração & dosagem , Administração Oral , Animais , Disponibilidade Biológica , Glicemia/química , Difusão , Humanos , Concentração de Íons de Hidrogênio , Substâncias Macromoleculares/química , Peptídeos/administração & dosagem , Peptídeos/química , Permeabilidade , Polímeros/química , Fatores de Tempo
13.
Nanomedicine (Lond) ; 11(22): 3009-3032, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27781558

RESUMO

Biopharmaceutics have been recognized as the drugs of choice for the treatment of several diseases, mainly due to their high selectivity and potent action. Nonetheless, their oral administration is a rather challenging problem, since their bioavailability is significantly hindered by various physiological barriers along the GI tract, including their acid-induced hydrolysis in the stomach, their enzymatic degradation throughout the GI tract and their poor mucosa permeability. Lipid-based nanocarriers represent a viable means for enhancing the oral bioavailability of biomolecules while diminishing toxicity-related issues. The present review describes the main physiological barriers limiting the oral bioavailability of macromolecules and highlights recent advances in the field of lipid-based carriers as well as the respective lipid intestinal absorption mechanisms.


Assuntos
Biofarmácia , Portadores de Fármacos/química , Lipídeos/química , Nanopartículas/química , Administração Oral , Portadores de Fármacos/administração & dosagem , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/fisiologia , Humanos , Absorção Intestinal/efeitos dos fármacos , Lipídeos/administração & dosagem , Nanopartículas/administração & dosagem
14.
Eur J Pharm Biopharm ; 105: 18-31, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27235727

RESUMO

Poly(lactide-co-glycolide) nanoparticles (PLGA NPs) represent a new approach for vaccine delivery due to their ability to be taken up by phagocytes and to activate immune responses. In the present study PLGA NPs were surface-modified with a TNFα mimicking peptide, and encapsulated soluble Leishmania antigens (sLiAg) and MPLA adjuvant. The synthesized PLGA NPs exhibited low cytotoxicity levels, while surface-modified NPs were more efficiently taken up by dendritic cells (DCs). The prepared nanoformulations induced maturation and functional differentiation of DCs by elevating co-stimulatory molecule levels and stimulating IL-12 and IL-10 production. Sensitized DCs promoted T cell priming, characterized by the development of mixed T cell subsets differentiation expressing Th lineage-specific transcriptional factors and cytokine genes. Moreover, PLGA NPs were biocompatible, while they were located in lymphoid organs and taken up by phagocytic cells. Our results suggest that surface-modified PLGA NPs encapsulating sLiAg and MPLA could be considered as an effective vaccine candidate against leishmaniasis.


Assuntos
Antígenos de Protozoários/imunologia , Diferenciação Celular , Ácido Láctico/química , Leishmania/imunologia , Nanopartículas/química , Peptídeos/química , Ácido Poliglicólico/química , Linfócitos T/imunologia , Fator de Necrose Tumoral alfa/química , Adjuvantes Imunológicos/administração & dosagem , Animais , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Copolímero de Ácido Poliláctico e Ácido Poliglicólico
15.
Eur J Pharm Biopharm ; 97(Pt A): 223-9, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25933940

RESUMO

The development of a novel, mucus permeating SNEDDS formulation for oral insulin delivery containing a hydrophobic ion pair of insulin/dimyristoyl phosphatidylglycerol (INS/DMPG) is presented. Three oil/surfactant/cosurfactant combinations and 27 weight ratios of oil, surfactant and cosurfactant for each combination were evaluated with the aid of ternary phase diagrams, for the incorporation of the protein/phospholipid complex. The developed formulation was characterized by an average droplet diameter of 30-45 nm. Depending on the initial protein concentration, the loading of insulin in SNEDDS varied between 0.27 and 1.13 wt%. The therapeutic protein was found to be efficiently protected from enzymatic degradation by intestinal enzymes (i.e., trypsin, α-chymotrypsin). The SNEDDS formulation exhibited increased mucus permeability and did not appear to be affected by ionic strength. The incorporation of INS/DMPG in SNEDDS prevented an initial burst release of insulin. INS/DMPG loaded SNEDDS were found to be non-cytotoxic up to a concentration of 2mg/ml. According to the reported results, the incorporation of the hydrophobic ion pair of INS/DMPG in SNEDDS could be regarded as a promising strategy for the oral delivery of insulin.


Assuntos
Sistemas de Liberação de Medicamentos , Insulina/administração & dosagem , Muco/metabolismo , Nanopartículas , Administração Oral , Animais , Química Farmacêutica/métodos , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Emulsões , Insulina/farmacocinética , Tamanho da Partícula , Permeabilidade , Transição de Fase , Fosfatidilgliceróis/química , Tensoativos/química , Suínos
16.
Eur J Pharm Biopharm ; 97(Pt A): 239-49, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25661586

RESUMO

The synthesis of nanocarriers with "slippery" surface (i.e., poly(lactide-co-glycolide)-polyethylene glycol (PLGA-PEG) nanoparticles (NPs) and polyelectrolyte complexes (PECs) of polyacrylic acid (PAA) with poly-L-lysine (PLL) and/or polyarginine (PArg)) and of nanocarriers (i.e., PLGA NPs, PLGA-PEG NPs, liposomes) containing a mucolytic agent (i.e., 4-mercaptobenzoic acid (4MBA)) is presented. Depending on the molecular weight (MW) of PEG (i.e., 2, 5 kDa), PLGA-PEG NPs with a "brush" or "dense brush" PEG configuration were prepared. The PLGA-PEG NPs exhibited increased mucus permeability in comparison with non-pegylated PLGA NPs when tested in fresh porcine intestinal mucus. The NPs that were prepared using PEG with a MW equal to 5 kDa and had a "dense brush" PEG configuration, were found to exhibit the highest mucus permeability. The average size and the surface charge of PECs could be effectively tuned by varying the PAA/polycation charge ratio, thus resulting in the synthesis of neutral as well as positively and negatively charged PECs. The PECs with negative surface charges were found to exhibit the highest mucus permeability followed by the neutral and finally the positively charged PECs. Depending on the initial concentration of the mucolytic agent, 4MBA loadings up to 13.65, 13.1 and 18.43 wt% were achieved for PLGA NPs, PLGA-PEG NPs and liposomes, respectively. PLGA and PLGA-PEG NPs were characterized by a rapid release of the mucolytic agent (i.e., >80 wt% of 4MBA was released in 20 min) whereas, its encapsulation in liposomes allowed a more controlled release (i.e., up to 30 wt% of 4MBA was released in 45 min). 4MBA loaded liposomes were found to exhibit increased mucus permeability depending on the composition of the phospholipid bilayer.


Assuntos
Benzoatos/administração & dosagem , Portadores de Fármacos/química , Muco/metabolismo , Nanopartículas , Compostos de Sulfidrila/administração & dosagem , Animais , Benzoatos/química , Química Farmacêutica/métodos , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Expectorantes/administração & dosagem , Expectorantes/química , Lipossomos , Peso Molecular , Tamanho da Partícula , Permeabilidade , Fosfolipídeos/química , Polietilenoglicóis/química , Poliglactina 910/química , Polímeros/química , Compostos de Sulfidrila/química , Suínos
17.
Artigo em Inglês | MEDLINE | ID: mdl-23971966

RESUMO

A computational model for flow and particle deposition in a three-dimensional representation of the human nasal cavity is developed. Simulations of steady state and dynamic airflow during inhalation are performed at flow rates of 9-60 l/min. Depositions for particles of size 0.5-20 µm are determined and compared with experimental and simulation results from the literature in terms of deposition efficiencies. The nasal model is validated by comparison with experimental and simulation results from the literature for particle deposition under steady-state flow. The distribution of deposited particles in the nasal cavity is presented in terms of an axial deposition distribution as well as a bivariate axial deposition and particle size distribution. Simulations of dynamic airflow and particle deposition during an inhalation cycle are performed for different nasal cavity outlet pressure variations and different particle injections. The total particle deposition efficiency under dynamic flow is found to depend strongly on the dynamics of airflow as well as the type of particle injection.


Assuntos
Simulação por Computador , Hidrodinâmica , Cavidade Nasal/fisiologia , Material Particulado/efeitos adversos , Ventilação Pulmonar/fisiologia , Reologia , Administração por Inalação , Humanos , Tamanho da Partícula , Pressão
18.
J Control Release ; 161(3): 781-94, 2012 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-22659331

RESUMO

This review highlights the recent developments in the area of nanocarrier-based mucosal delivery of therapeutic biomolecules and antigens. Macromolecular drugs have the unique power to tackle challenging diseases but their structure, physicochemical properties, stability, pharmacodynamics, and pharmacokinetics place stringent demands on the way they are delivered into the body (e.g., inability to cross mucosal surfaces and biological membranes). Carrier-based drug delivery systems can diminish the toxicity of therapeutic biomolecules, improve their bioavailability and make possible their administration via less-invasive routes (e.g., oral, nasal, pulmonary, etc.). Thus, the development of functionalized nanocarriers and nanoparticle-based microcarriers for the delivery of macromolecular drugs is considered an important scientific challenge and at the same time a business breakthrough for the biopharmaceutical industry. In order to be translated to the clinic the nanocarriers need to be biocompatible, biodegradable, stable in biological media, non-toxic and non-immunogenic, to exhibit mucoadhesive properties, to cross mucosal barriers and to protect their sensitive payload and deliver it to its target site in a controlled manner, thus increasing significantly its bioavailability and efficacy.


Assuntos
Portadores de Fármacos/administração & dosagem , Membrana Mucosa/metabolismo , Nanopartículas/administração & dosagem , Animais , Antígenos/administração & dosagem , Humanos , Peptídeos/administração & dosagem , Proteínas/administração & dosagem , Vacinas/administração & dosagem
19.
Biotechnol Adv ; 30(1): 329-37, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-21756991

RESUMO

The microbial production of polyhydroxybutyrate (PHB) is a complex process in which the final quantity and quality of the PHB depend on a large number of process operating variables. Consequently, the design and optimal dynamic operation of a microbial process for the efficient production of PHB with tailor-made molecular properties is an extremely interesting problem. The present study investigates how key process operating variables (i.e., nutritional and aeration conditions) affect the biomass production rate and the PHB accumulation in the cells and its associated molecular weight distribution. A combined metabolic/polymerization/macroscopic modelling approach, relating the process performance and product quality with the process variables, was developed and validated using an extensive series of experiments and measurements. The model predicts the dynamic evolution of the biomass growth, the polymer accumulation, the consumption of carbon and nitrogen sources and the average molecular weights of the PHB in a bioreactor, under batch and fed-batch operating conditions. The proposed integrated model was used for the model-based optimization of the production of PHB with tailor-made molecular properties in Azohydromonas lata bacteria. The process optimization led to a high intracellular PHB accumulation (up to 95% g of PHB per g of DCW) and the production of different grades (i.e., different molecular weight distributions) of PHB.


Assuntos
Alcaligenaceae/metabolismo , Hidroxibutiratos/metabolismo , Modelos Biológicos , Poli-Hidroxialcanoatos/metabolismo , Sulfato de Amônio , Biomassa , Biopolímeros , Reatores Biológicos , Meios de Cultura , Fermentação , Hidroxibutiratos/química , Cinética , Peso Molecular , Poli-Hidroxialcanoatos/química , Sacarose
20.
Biomaterials ; 32(16): 4052-7, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21377204

RESUMO

Although oral vaccination has numerous advantages over the commonly used parenteral route, degradation of vaccine and its low uptake in the lymphoid tissue of the gastrointestinal (GI) tract still impede their development. In this study, the model antigen ovalbumin (OVA) and the immunostimulant monophosphoryl lipid A (MPLA) were incorporated in polymeric nanoparticles based on poly(D,L-lactide-co-glycolide) (PLGA). These polymeric carriers were orally administered to BALB/c mice (Bagg albino, inbred strain of mouse) and the resulting time-dependent systemic and mucosal immune responses towards OVA were assessed by measuring the OVA-specific IgG and IgA titers using an enzyme-linked immunosorbent assay (ELISA). PLGA nanoparticles were spherical in shape, around 320 nm in size, negatively charged (around -20 mV) and had an OVA and MPLA payload of 9.6% and 0.86%, respectively. A single immunization with formulation containing (OVA + MPLA) incorporated in PLGA nanoparticles induced a stronger IgG immune response than that induced by OVA in PBS solution or OVA incorporated into PLGA nanoparticles. Moreover, significantly higher IgA titers were generated by administration of (OVA + MPLA)/PLGA nanoparticles compared to IgA stimulated by control formulations, proving the capability of inducing a mucosal immunity. These findings demonstrate that co-delivery of OVA and MPLA in PLGA nanoparticles promotes both systemic and mucosal immune responses and represents therefore a suitable strategy for oral vaccination.


Assuntos
Ácido Láctico/química , Lipídeo A/análogos & derivados , Nanopartículas/química , Ácido Poliglicólico/química , Vacinação/métodos , Adjuvantes Imunológicos , Animais , Ensaio de Imunoadsorção Enzimática , Lipídeo A/química , Lipídeo A/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Varredura , Nanopartículas/ultraestrutura , Ovalbumina/imunologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico
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