ApoE-modified solid lipid nanoparticles: A feasible strategy to cross the blood-brain barrier.

Solid lipid nanoparticles (SLN) are colloidal drug delivery systems characterized by higher entrapment efficiency, good scalability of the preparation process and increased sustained prolonged release of the payload compared to other nanocarriers. The possibility to functionalize the surface of SLN with ligands to achieve a site specific targeting makes them attractive to overcome the limited blood-brain barrier (BBB) penetration of therapeutic compounds. SLN are prepared for brain targeting by exploiting the adaptability of warm microemulsion process for the covalent surface modification with an Apolipoprotein E-derived peptide (SLN-mApoE). Furthermore, the influence of the administration route on SLN-mApoE brain bioavailability is here evaluated. SLN-mApoE are able to cross intact a BBB in vitro model. The pulmonary administration of SLN-mApoE is related to a higher confinement in the brain of Balb/c mice compared to the intravenous and intraperitoneal administration routes, without inducing any acute inflammatory reaction in the lungs. These results promote the pulmonary administration of brain-targeted SLN as a feasible strategy for improving brain delivery of therapeutics.

Effects of laser biostimulation on the epithelial tissue for keratinized layer differentiation: an in vitro study.

Gingival augmentation techniques proposed in the international literature do not exclude a surgical component, which determines consequent post-surgical discomfort and results are not always predictable. In recent years, the introduction of laser biostimulation has led to a less invasive approach, particularly in the treatment of periodontally compromised patients, limiting the surgical phase to seriously compromised cases, with regeneration techniques for the restoration of a correct periodontal tissue anatomy. The aim of this in vitro study is to establish the validity of laser biostimulation in order to develop the epithelial keratinized layer of the tissue by stimulating fibroblasts-keratinocytes organotypic cultures and fibroblasts and keratinocytes mono-cultures. We created two groups (test and control), each one composed of 3 fibroblast cultures, 3 keratinocyte cultures and 3 organotypic cultures. We performed laser irradiation of test group with Wiser Doctor Smile Lambda, Flat Top Handpiece, at 50 J/cm2 of fluency with one application every 40 h for a total of 5 applications. Forty-eight h after the last laser application, we investigated the presence and amount of keratins 5 and 8 with citofluorymetric and western blotting analyses. Analyses showed an increase in keratin synthesis in test group cultures, showing a remarkable increase in production of keratin 8 in co-cultures test. Laser biostimulation can considerably enhance keratin synthesis when applied with high energy doses and repeated applications to keratinocytes-fibroblasts co-cultures.

GMP-grade preparation of biomimetic scaffolds with osteo-differentiated autologous mesenchymal stromal cells for the treatment of alveolar bone resorption in periodontal disease.

BACKGROUND: Periodontal disease is a degenerative illness that leads to resorption of the alveolar bone. Mesenchymal stromal cells (MSC) represent a novel tool for the production of biologic constructs for the treatment of degenerative bone diseases. The preparation of MSC differentiated into osteogenic lineage for clinical use requires the fulfillment of strict good manufacturing practice (GMP) procedures. METHODS: MSC were isolated from BM samples and then cultured under GMP conditions. MSC were characterized phenotypically and for their differentiative potential. Cells were seeded onto collagen scaffolds (Gingistat) and induced to differentiate into osteogenic lineages using clinical grade drugs compared with standard osteogenic supplements. Alizarin Red S stain was used to test the deposition of the mineral matrix. Standard microbiologic analysis was performed to verify the product sterility. RESULTS: The resulting MSC were negative for CD33, CD34 and HLA-DR but showed high expression of CD90, CD105 and HLA-ABC (average expressions of 94.3%, 75.8% and 94.2%, respectively). Chondrogenic, osteogenic and adipogenic differentiation potential was demonstrated. The MSC retained their ability to differentiate into osteogenic lineage when seeded onto collagen scaffolds after exposure to a clinical grade medium. Cell numbers and cell viability were adequate for clinical use, and microbiologic assays demonstrated the absence of any contamination. DISCUSSION: In the specific context of a degenerative bone disease with limited involvement of skeletal tissue, the combined use of MSC, exposed to an osteogenic clinical grade medium, and biomimetic biodegradable scaffolds offers the possibility of producing adequate numbers of biologic tissue-engineered cell-based constructs for use in clinical trials.

Mesenchymal stem cells cultured on a collagen scaffold: In vitro osteogenic differentiation.

OBJECTIVE: Management of periodontal defects has always been a challenge in clinical periodontics. Recently mesenchymal stem cells (MSC) have been proposed for tissue regeneration in periodontal disease and repair of large bone defects. Bone regeneration has to be supported by a scaffold which has to be biocompatible, biodegradable, and able to support cell growth and differentiation. The aim of this study was to evaluate osteogenic differentiation of MSC seeded on a collagen scaffold. DESIGN: MSC were obtained from adult rat bone marrow, expanded and cultured in plastic dishes or seeded in a collagen scaffold (Gingistat). MSC were induced towards osteogenic differentiation using osteogenic supplements. Cell differentiation and calcium deposits were evaluated by immunoblotting, immunohistochemistry, histochemical techniques, enzymatic activity assay, and SEM-EDX analysis. Biomaterial in vitro degradation was evaluated by measuring mass reduction after incubation in culture medium. RESULTS: Rat MSC osteogenic differentiation was demonstrated by osteopontin and osteocalcin expression and an increase in alkaline phosphatase activity. MSC were distributed homogeneously in the collagen scaffold. Nodular aggregates and alizarin red stained calcium deposits were observed in MSC induced towards osteogenic differentiation cultured in dishes or seeded in the collagen scaffold. SEM-EDX analysis demonstrated that calcium co-localized with phosphorous. The biomaterial in vitro degraded in 4-5 weeks. CONCLUSIONS: MSC from bone marrow differentiate towards osteogenic lineage, representing a suitable cell source for bone formation in periodontal regeneration. Gingistat collagen scaffold supports MSC distribution and differentiation, but its short degradation time may be a limitation for a future application in bone tissue regeneration.