Efeitos da nanopartícula de ácido poli lático-co-glicólico (PLGA) associada ao cloridrato de metformina na doença periodontal em ratos diabéticos / Effects of polylactic-co-glycolic acid (PLGA) nanoparticle associated with metformin hydrochloride on periodontal disease in diabetic rats

Existe uma associação entre diabetes e a periodontite, e a Metformina (MET) além de controlar os níveis glicêmicos, tem apresentado efeitos antiinflamatórios e na diminuição da perda óssea periodontal. Ao se veicular a MET a um sistema de nanopartículas pode-se apresentar a vantagem de aumento da eficácia terapêutica. Objetivos: esse estudo consistiu na avaliação dos efeitos antiinflamatórios, perda óssea e disponibilidade in vitro/in vivo de uma nanopartícula de ácido poli lático-co-glicólico (PLGA) associada à MET em um modelo de periodontite induzida por ligadura. Materiais e métodos: o PLGA carreado com diferentes doses da MET foi caracterizado pelo seu diâmetro médio, tamanho da partícula, índice de polidispensão e eficiência de aprisionamento. Foram utilizados ratos machos da linhagem Wistar, divididos aleatoriamente, em grupos controles e experimentais com diferentes doses de MET associadas ou não ao PLGA, os quais receberam diferentes tratamentos. Amostras de maxilas e tecidos gengivais foram utilizadas para avaliação de perda óssea e inflamação, por meio da microtomografia computadorizada, histopatológico, imunohistoquímica, análise de citocinas inflamatórias e expressão gênica de proteínas por RT-PCR quantitativo. Para o ensaio de liberação in vitro, utilizou-se o dispositivo de células de difusão vertical de Franz estáticas. Para a disponibilidade in vivo, as amostras de sangue foram coletadas em diferentes intervalos de tempo e analisadas por cromatografia líquida de alta eficiência acoplado a espectrometria de massas (HPLC-MS/MS). Resultados: o diâmetro médio das nanopartículas de PLGA carreadas com MET estava em um intervalo de 457,1 ± 48,9 nm (p <0,05) com um índice de polidispersidade de 0,285 (p <0,05), potencial Z de 8,16 ± 1,1 mV (p <0,01) e eficiência de aprisionamento (EE) de 66,7 ± 3,73. O tratamento com a MET 10 mg / kg + PLGA mostrou uma baixa concentração de células inflamatórias, fraca imunomarcação para RANKL, Catepsina K, OPG e osteocalcina. Diminuição dos níveis de IL-1ß e TNF-α (p <0,05), aumento da expressão gênica do AMPK (p <0,05) e diminuição do NF-κB p65, HMGB1 e TAK-1 (p <0,05). O 10 mg/kg MET + PLGA foi liberado no ensaio in vitro sugerindo um modelo cinético de difusão parabólica com um perfil de liberação que atinge 50% de seu conteúdo em 2h e permanece em liberação constante em torno de 60% até o final de 6h. O ensaio in vivo mostrou o volume aparente de distribuição Vz/F (10 mg/kg MET + PLGA, 46,31 mL/kg vs. 100 mg/kg MET + PLGA, 28,8 mL/kg) e o tempo médio de residência MRTinf (PLGA + MET 10 mg /kg, 37,66h vs. MET 100 mg/kg, 3,34h). Conclusão: o PLGA carreado com MET diminuiu a inflamação e a perda óssea na periodontite em ratos diabéticos. O 10 mg/kg MET + PLGA teve uma taxa de eliminação mais lenta em comparação com o MET 100 mg/kg. A formulação modifica os parâmetros farmacocinéticos, como volume de distribuição aparente e tempo médio de residência (AU).

There is an association between diabetes and periodontitis, and Metformin (MET) in addition to controlling glycemic levels, has shown anti-inflammatory effects and decreased periodontal bone loss. By transferring MET to a nanoparticle system, the advantage of increasing therapeutic efficacy can be presented. Objectives: this study consisted of evaluating the antiinflammatory effects, bone loss and in vitro/in vivo availability of a polylactic-co-glycolic acid (PLGA) nanoparticle associated with MET in a ligature-induced periodontitis model. Materials and methods: PLGA loaded with different doses of MET was characterized by its mean diameter, particle size, polydispension index and entrapment efficiency. Male Wistar rats were used, randomly divided into control and experimental groups with different doses of MET associated or not with PLGA, which received different treatments. Samples of jaws and gingival tissues were used to assess bone loss and inflammation, using computed microtomography, histopathology, immunohistochemistry, analysis of inflammatory cytokines and gene expression of proteins by quantitative RT-PCR. For the in vitro release assay, the static Franz vertical diffusion cell device was used. For in vivo availability, blood samples were collected at different time intervals and analyzed by high performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS). Results: the mean diameter of MET-loaded PLGA nanoparticles was in the range of 457.1 ± 48.9 nm (p <0.05) with a polydispersity index of 0.285 (p <0.05), Z potential of 8.16 ± 1.1 mV (p <0.01) and trapping efficiency (EE) of 66.7 ± 3.73. Treatment with MET 10 mg/kg + PLGA showed a low concentration of inflammatory cells, weak immunostaining for RANKL, Cathepsin K, OPG and osteocalcin. Decreased IL-1ß and TNF-α levels (p <0.05), increased AMPK gene expression (p <0.05) and decreased NF-κB p65, HMGB1 and TAK-1 (p <0. 05). The 10 mg/kg MET + PLGA was released in the in vitro assay suggesting a kinetic model of parabolic diffusion with a release profile that reaches 50% of its content in 2h and remains in constant release around 60% until the end of 6h . The in vivo assay showed the apparent volume of distribution Vz/F (10 mg/kg MET + PLGA, 46.31 mL/kg vs. 100 mg/kg MET + PLGA, 28.8 mL/kg) and the mean MRTinf residency (PLGA + MET 10 mg/kg, 37.66h vs. MET 100 mg/kg, 3.34h). Conclusion: MET-loaded PLGA decreased inflammation and bone loss in periodontitis in diabetic rats. 10 mg/kg MET + PLGA had a slower rate of elimination compared to 100 mg/kg MET. The formulation modifies pharmacokinetic parameters such as apparent volume of distribution and mean residence time (AU).

A dose-related positive effect of inhaled simvastatin-loaded PLGA nanoparticles on paraquat-induced pulmonary fibrosis in rats.

OBJECTIVE: Pulmonary fibrosis is an important complication of subacute paraquat (PQ) poisoning. Here, we reported a novel nanotherapeutic platform for PQ-induced pulmonary fibrosis in animal inhalation models using simvastatin (SV)-loaded into poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs). METHODS AND MATERIALS: Eight inhalations of normal saline, PQ (24 mg/kg), PQ plus SV (20 mg/kg), PQ plus SV-loaded PLGA NPs at doses of 5, 10 or 20 mg/kg or PQ plus PLGA NPs were given to rats. After the end of the treatment period, inflammatory factors and creatine phosphokinase as well as lung pathological changes and tracheal responsiveness were evaluated. RESULTS: Inhalation of SV-loaded PLGA NPs could significantly prevent the progression of PQ-induced pulmonary fibrosis especially at a dose of 10 mg through decreasing the serum level of inflammatory factors as well as contractile responses (p < 0.001) compared to PQ group. Pathological findings also confirmed the results. However, inhalation of non-formulated SV could not prevent tissue damage and fibrosis in comparision with SV-loaded PLGA NPs. CONCLUSION: Taken together, the present work provides us an idea about the pulmonary delivery of PLGA-SV NPs using nebulizer for the treatment of PQ poisoning. However, the efficacy of this formulation in human beings and clinical use needs to be more investigated.

Intra-amniotic Injection of Poly(lactic-co-glycolic Acid) Microparticles Loaded with Growth Factor: Effect on Tissue Coverage and Cellular Apoptosis in the Rat Model of Myelomeningocele.

BACKGROUND: Myelomeningocele (MMC) is a devastating congenital neurologic disorder that can lead to lifelong morbidity and has limited treatment options. This study investigates the use of poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) loaded with fibroblast growth factor (FGF) as a platform for in utero treatment of MMC. STUDY DESIGN: Intra-amniotic injections of PLGA MPs were performed on gestational day 17 (E17) in all-trans retinoic acid-induced MMC rat dams. MPs loaded with fluorescent dye (DiO) were evaluated 3 hours after injection to determine incidence of binding to the MMC defect. Fetuses were then treated with PBS or PLGA particles loaded with DiO, bovine serum albumin, or FGF and evaluated at term (E21). Fetuses with MMC defects were evaluated for gross and histologic evidence of soft tissue coverage. The effect of PLGA-FGF treatment on spinal cord cell death was evaluated using an in situ cell death kit. RESULTS: PLGA-DiO MPs had a binding incidence of 86% and 94% 3 hours after injection at E17 for doses of 0.1 mg and 1.2 mg, respectively. Incidence of soft tissue coverage at term was 19% (4 of 21), 22% (2 of 9), and 83% (5 of 6) for PLGA-DiO, PLGA-BSA, and PLGA-FGF, respectively. At E21, the percentage of spinal cord cells positive for in situ cell death was significantly higher in MMC controls compared with wild-type controls or MMC pups treated with PLGA-FGF. CONCLUSION: PLGA MPs are an innovative minimally invasive platform for induction of soft tissue coverage in the rat model of MMC and may reduce cellular apoptosis.

Safety of Contemporary Resorbable Fixation Systems for Craniofacial Reconstruction in Pediatric Patients.

BACKGROUND: Resorbable hardware allows adequate strength for maintaining the relative position of the craniofacial skeleton during osseous healing, and allowing subsequent growth in pediatric patients. The purpose of this study was to determine the complication profile of the latest copolymer of resorbable plates for craniofacial reconstruction in pediatric patients. METHODS: Retrospective query of the operative billing record was performed for use of the DePuy Synthes Rapidsorb Fixation System at the authors' tertiary children's hospital from 2015 to 2019. Three hundred twenty-five patients were randomly selected for analysis of complications within the first postoperative year. RESULTS: Median age at craniofacial reconstruction was 3.0 years, with 127 procedures (39.9 percent) performed for an intracranial mass and 141 procedures (44.3 percent) performed for craniosynostosis. Overall, 7.9 percent patients had a postoperative wound complication. The most common complications were dehiscence (3.8 percent), hematoma/seroma (3.5 percent), and infection (2.5 percent). There were no instances of extrusion, plate fracture, or screw loosening. Hardware complications in the temporoparietal region were more likely to occur at incision sites (p = 0.001), whereas wound complications at the frontal region were more likely to occur away from incision sites (p < 0.001). There were no differences in complications between plates secured with resorbable screws or with the resorbable injectable polymer system (p ≥ 0.161 for all). Radiotherapy was significantly implicated in development of clinical infection (p = 0.001), culture-positive infection (p < 0.001), readmission (p = 0.007), reoperation (p = 0.003), and plate removal (p = 0.007). CONCLUSION: Resorbable cranial hardware has an overall favorable complication profile for craniofacial reconstruction in pediatric patients undergoing surgical intervention for craniosynostosis or intracranial mass resection.

Carbol fuchsin stain enhances detection of poly-(d, l-lactide-co-glycolide) microspheres in exenatide extended-release cutaneous injection-site foreign body reaction.

Injection of high-viscosity fluids into subcutaneous tissues may lead to a granulomatous reaction called sclerosing lipogranuloma (SL). Poly-(d,l-lactide-co-glycolide) (PLG or PLGA) microspheres are used as vehicles for extended-release drugs. Here we describe the histopathologic features of a case of SL induced by exenatide extended-release injections, and the staining pattern of PLG microspheres and microsphere remnants with carbol fuchsin.

Poly(lactide- co-glycolide) Nanoparticles for Prolonged Therapeutic Efficacy of Esculentin-1a-Derived Antimicrobial Peptides against Pseudomonas aeruginosa Lung Infection: in Vitro and in Vivo Studies.

Due to their excellent in vitro activity against multidrug resistant bacteria, antimicrobial peptides (AMPs) hold promise for treatment of Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) sufferers. In this work, poly(lactide- co-glycolide) (PLGA) nanoparticles for lung delivery of AMPs deriving from the frog-skin esculentin-1a, namely, Esc(1-21) and Esc(1-21)-1c (Esc peptides), were successfully developed. Improved peptide transport through artificial CF mucus and simulated bacterial extracellular matrix was achieved in vitro. The formulations were effectively delivered through a liquid jet nebulizer already available to patients. Notably, Esc peptide-loaded nanoparticles displayed an improved efficacy in inhibiting P. aeruginosa growth in vitro and in vivo in the long term. A single intratracheal administration of Esc peptide-loaded nanoparticles in a mouse model of P. aeruginosa lung infection resulted in a 3-log reduction of pulmonary bacterial burden up to 36 h. Overall, results unravel the potential of PLGA nanoparticles as a reliable delivery system of AMPs to lungs.

NIR-Light-Triggered Anticancer Strategy for Dual-Modality Imaging-Guided Combination Therapy via a Bioinspired Hybrid PLGA Nanoplatform.

A promising approach toward cancer therapy is expected to integrate imaging and therapeutic agents into a versatile nanocarrier for achieving improved antitumor efficacy and reducing the side effects of conventional chemotherapy. Herein, we designed a poly(d,l-lactic- co-glycolic acid) (PLGA)-based theranostic nanoplatform using the double emulsion solvent evaporation method (W/O/W), which is associated with bovine serum albumin (BSA) modifications, to codeliver indocyanine green (ICG), a widely used near-infrared (NIR) dye, and doxorubicin (Dox), a chemotherapeutic drug, for dual-modality imaging-guided chemo-photothermal combination cancer therapy. The resultant ICG/Dox co-loaded hybrid PLGA nanoparticles (denoted as IDPNs) had a diameter of around 200 nm and exhibited excellent monodispersity, fluorescence/size stability, and biocompatibility. It was confirmed that IDPNs displayed a photothermal effect and that the heat induced faster release of Dox, which led to enhanced drug accumulation in cells and was followed by their efficient escape from the lysosomes into the cytoplasm and drug diffusion into the nucleus, resulting in a chemo-photothermal combinatorial therapeutic effect in vitro. Moreover, the IDPNs exhibited a high ability to accumulate in tumor tissue, owing to the enhanced permeability and retention (EPR) effect, and could realize real-time fluorescence/photoacoustic imaging of solid tumors with a high spatial resolution. In addition, the exposure of tumor regions to NIR irradiation could enhance the tumor penetration ability of IDPNs, almost eradicating subcutaneous tumors. In addition, the inhibition rate of IDPNs used in combination with laser irradiation against EMT-6 tumors in tumor-bearing nude mice (chemo-photothermal therapy) was approximately 95.6%, which was much higher than that for chemo- or photothermal treatment alone. Our study validated the fact that the use of well-defined IDPNs with NIR laser treatment could be a promising strategy for the early diagnosis and passive tumor-targeted chemo-photothermal therapy for cancer.

Intramedullary nailing of forearm shaft fractures by biodegradable compared with titanium nails: Results of a prospective randomized trial in children with at least two years of follow-up.

There are disadvantages in Elastic Stable Intramedullary Nailing (ESIN) of forearm-shaft fractures, such as the need of implant removal. Biodegradable Intramedullary Nailing (BIN) is a new technique developed for these fractures. We hypothesized that there is no difference in rotational ROM between the patients treated by BIN vs. ESIN. A randomized, controlled clinical trial included patients, aged 5-15 years, requiring surgery for forearm-shaft fractures. Biodegradable polylactide-co-glycolide (PLGA) nails (Activa IM-Nail™, Bioretec Ltd., Finland) were used in 19 and titanium nails (TEN®, SynthesDePuy Ltd., USA) in 16 patients. Rotational ROM of forearm after two years was the primary outcome. Elbow and wrist ROM, pain and radiographic bone healing were secondary outcomes. Forearm rotation was mean 162° and 151° in BIN and ESIN groups, respectively (P = 0.201). No difference between the groups was found in any other ROMs. Three cases in the ESIN vs. none in the BIN group reported pain (P = 0.113). There was no clinically significant residual angulation in radiographs. Two adolescents in the BIN group vs. none in the ESIN (P = 0.245) were excluded because of implant failure; another two with complete bone union suffered from re-injury. Therefore, satisfactory implant stability among older children needs to be studied.

Biodegradable Polymer Nanoparticles for Photodynamic Therapy by Bioluminescence Resonance Energy Transfer.

Conventional photodynamic therapy is severely constrained by the limited light-penetration depth in tissue. Here, we show efficient photodynamic therapy (PDT) mediated by bioluminescence resonance energy transfer (BRET) that overcomes the light-penetration limitation. The photosensitizer Rose Bengal (RB) was loaded in biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles, which were then conjugated with firefly luciferase. Spectroscopic characterizations indicated that BRET effectively activated RB to generate reactive oxygen species (ROS). In vitro studies of the cellular cytotoxicity and photodynamic effect indicated that cancer cells were effectively destroyed by BRET-PDT treatment. In vivo studies in a tumor-bearing mouse model demonstrated that tumor growth was significantly inhibited by BRET-PDT in the absence of external light irradiation. The BRET-mediated phototherapy provides a promising approach to overcome the light-penetration limitation in photodynamic treatment of deep-seated tumors.