Lactoferrin in Bone Tissue Regeneration.

Among the multiple properties exhibited by lactoferrin (Lf), its involvement in bone regeneration processes is of great interest at the present time. A series of in vitro and in vivo studies have revealed the ability of Lf to promote survival, proliferation and differentiation of osteoblast cells and to inhibit bone resorption mediated by osteoclasts. Although the mechanism underlying the action of Lf in bone cells is still not fully elucidated, it has been shown that its mode of action leading to the survival of osteoblasts is complemented by its mitogenic effect. Activation of several signalling pathways and gene expression, in an LRPdependent or independent manner, has been identified. Unlike the effects on osteoblasts, the action on osteoclasts is different, with Lf leading to a total arrest of osteoclastogenesis. Due to the positive effect of Lf on osteoblasts, the potential use of Lf alone or in combination with different biologically active compounds in bone tissue regeneration and the treatment of bone diseases is of great interest. Since the bioavailability of Lf in vivo is poor, a nanotechnology- based strategy to improve the biological properties of Lf was developed. The investigated formulations include incorporation of Lf into collagen membranes, gelatin hydrogel, liposomes, loading onto nanofibers, porous microspheres, or coating onto silica/titan based implants. Lf has also been coupled with other biologically active compounds such as biomimetic hydroxyapatite, in order to improve the efficacy of biomaterials used in the regulation of bone homeostasis. This review aims to provide an up-to-date review of research on the involvement of Lf in bone growth and healing and on its use as a potential therapeutic factor in bone tissue regeneration.

Cytotoxicity and intracellular fate of PLGA and chitosan-coated PLGA nanoparticles in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells.

Polymeric nanoparticles (NPs) are known to facilitate intracellular uptake of drugs to improve their efficacy, with minimum bioreactivity. The goal of this study was to assess cellular uptake and trafficking of PLGA NPs and chitosan (Chi)-covered PLGA NPs in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells. Both PLGA and Chi-PLGA NPs were not cytotoxic to the studied cells at concentrations up to 2500 µg/mL. The positive charge conferred by the chitosan deposition on the PLGA NPs improved NPs uptake by MDBK cells. In this cell line, Chi-PLGA NPs colocalized partially with early endosomes compartment and showed a more consistent perinuclear localization than PLGA NPs. Kinetic uptake of PLGA NPs by Colo 205 was slower than that by MDBK cells, detected only at 24 h, exceeding that of Chi-PLGA NPs. This study offers new insights on NP interaction with target cells supporting the use of NPs as novel nutraceuticals/drug delivery systems in metabolic disorders or cancer therapy. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3599-3611, 2015.

Liposomal formulation of chondroitin sulfate enhances its antioxidant and anti-inflammatory potential in L929 fibroblast cell line.

Liposomes have the capacity to be used as efficient, biodegradable and nontoxic carriers of bioactive molecules and are able to better control their delivery at the site of interest. The objective of this study was to obtain and characterize an appropriate liposomal formulation of the bioactive molecule chondroitin sulfate (CS) for its use in the local treatment of inflammatory and degenerative disorders, specifically osteoarthritis (OA). Empty liposomes (L) and CS-entrapping liposomes (L-CS) were prepared by thin film hydration method followed by sonication and extrusion. They were characterized in terms of size, polydispersity index and ζ-potential by dynamic light scattering (DLS) and morphology by transmission electron microscopy. The effect of L-CS formulation on viability and morphology of mouse fibroblast cells and its biologic activity in hydrogen peroxide-stimulated cells were compared to those of L, non-encapsulated CS and a mixture of L and CS (L + CS). Our results demonstrated a high biocompatibility of L-CS and a more efficient cell protection against oxidative damage using L-CS treatment than CS or L + CS treatment. Also, L-CS exhibited a higher anti-inflammatory activity than CS in stimulated cells by reducing the level of IL-8 and TNF-α proinflammatory cytokines. The overall results suggest that the delivery of CS in liposomal formulation could improve its therapeutic potential in intra-articular treatment of OA.

Liposomalization of lactoferrin enhanced its anti-tumoral effects on melanoma cells.

A number of studies have reported the anti-tumoral activity of lactoferrin, a property mediated by a variety of mechanisms such as inhibitory effects on tumor cell growth, NK cell activation, and enhancement of apoptosis. Liposomes are known to be an efficient drug delivery system which can enhance the therapeutic potential of the encapsulated compounds. We have used positively charged liposomes composed of phosphatidylcholine (PC), dioleoylphosphatidylethanolamine (DOPE), cholesterol (Chol) and stearylamine (SA) (6:1:2:1 M ratio) as a carrier system for bovine iron-free Lf (ApoBLf), and compared the in vitro effect of free and liposome-entrapped ApoBLf on the growth and morphology of murine melanoma B16-F10 cells. Liposomal formulation of ApoBLf was found to enhance the capacity of the protein to inhibit the cell proliferation by affecting cell cycle progression. The effect appeared to be due to the capacity of liposomes to increase the uptake of the protein and its accumulation into cells and probably to protect it from degradation, as revealed by fluorescence microscopy and flow cytometry. Our results demonstrate the ability of liposomes to improve the anti-tumor activity of Lf and suggest that liposomal protein may have a potential therapeutic use in the prevention and/or treatment of cancer diseases.

Liposomes-entrapped chondroitin sulphate: ultrastructural characterization and in vitro biocompatibility.

The purpose of this study was ultrastructural characterization of liposomes-entrapped chondroitin sulphate and to prove their in vitro biocompatibility in a human dermal fibroblast culture system, in order to use liposome-entrapped chondroitin sulphate in the treatment of inflammatory disorders. Chondroitin sulphate entrapped in liposomes appears as electron-dense particles in ultra-thin section. Comparative studies using chondroitin sulphate, empty liposomes and liposome-chondroitin sulphate systems were performed in order to evaluate their effect on growth and morphology of fibroblasts after 48 h of culture. Light microscopy indicated that chondroitin sulphate, empty liposomes and liposome-chondroitin sulphate systems do not induce appreciable cytotoxic effects, and cells maintain normal morphology when compared to control fibroblasts.