Engineered Delivery of Dental Stem-Cell-Derived Extracellular Vesicles for Periodontal Tissue Regeneration.

Periodontal disease begins as an inflammatory response to a bacterial biofilm deposited around the teeth, which over time leads to the destruction of tooth-supporting structures and consequently tooth loss. Conventional treatment strategies show limited efficacy in promoting regeneration of damaged periodontal tissues. Here, a delivery platform is developed for small extracellular vesicles (sEVs) derived from gingival mesenchymal stem cells (GMSCs) to treat periodontitis. EVs can achieve comparable therapeutic effects to their cells of origin. However, the short half-lives of EVs after their administration along with their rapid diffusion away from the delivery site necessitate frequent administration to achieve therapeutic benefits. To address these issues, "dual delivery" microparticles are engineered enabling microenvironment-sensitive release of EVs by metalloproteinases at the affected site along with antibiotics to suppress bacterial biofilm growth. GMSC sEVs are able to decrease the secretion of pro-inflammatory cytokines by monocytes/macrophages and T cells, suppress T-cell activation, and induce the formation of T regulatory cells (Tregs) in vitro and in a rat model of periodontal disease. One-time administration of immunomodulatory GMSC sEV-decorated microparticles leads to a significant improvement in regeneration of the damaged periodontal tissue. This approach will have potential clinical applications in the regeneration of a variety of tissues.

Immunomodulatory Microneedle Patch for Periodontal Tissue Regeneration.

Periodontal diseases are caused by microbial infection and the recruitment of destructive immune cells. Current therapies mainly deal with bacteria elimination, but the regeneration of periodontal tissues remains a challenge. Here we developed a modular microneedle (MN) patch that delivered both antibiotic and cytokines into the local gingival tissue to achieve immunomodulation and tissue regeneration. This MN patch included a quickly dissolvable gelatin membrane for an immediate release of tetracycline and biodegradable GelMA MNs that contained tetracycline-loaded poly(lactic-co-glycolic acid) nanoparticles and cytokine-loaded silica microparticles for a sustained release. Antibiotic release completely inhibited bacteria growth, and the release of IL-4 and TGF-ß induced the repolarization of anti-inflammatory macrophages and the formation of regulatory T cells in vitro. In vivo delivery of MN patch into periodontal tissues suppressed proinflammatory factors and promoted pro-regenerative signals and tissue healing, which demonstrated the therapeutic potential of local immunomodulation for tissue regeneration.

Unraveling the mechanobiology of immune cells.

Immune cells can sense and respond to biophysical cues - from dynamic forces to spatial features - during their development, activation, differentiation and expansion. These biophysical signals regulate a variety of immune cell functions such as leukocyte extravasation, macrophage polarization, T cell selection and T cell activation. Recent studies have advanced our understanding on immune responses to biophysical cues and the underlying mechanisms of mechanotransduction, which provides rational basis for the design and development of immune-modulatory therapeutics. This review discusses the recent progress in mechanosensing and mechanotransduction of immune cells, particularly monocytes/macrophages and T lymphocytes, and features new biomaterial designs and biomedical devices that translate these findings into biomedical applications.

[Peg-interferon alfa-2a and highly active antiretroviral drug therapy on hepatitis C patients with AIDS].

OBJECTIVE: To evaluate the clinical effect and side-effect of peg-interferon alfa-2a (PEG-IFN alfa-2a) and highly active antiretroviral therapy (HAART) for patients infected with hepatitis C virus (HCV) and co-infected with human immunodeficiency virus (HIV). METHODS: Twenty-two patients with HCV/HIV co-infection received highly active antiretroviral therapy initially; after their CD4 lymphocyte counts rose to over 0.20x10(9)/L, they were separated into two groups: one group with CD4 lymphocytes over 0.35x10(9)/L (high group) and one group with CD4 lymphocytes below 0.35x10(9)/L (low group). Both groups were given 180 microg of PEG-IFN alfa-2a every week intramuscularly. HCV RNA and HIV RNA loads, blood cell and CD4 lymphocyte counts, and liver functions were routinely examined. RESULTS: After 12, 24 and 48 weeks of PEG-IFN alfa-2a therapy, mean HCV RNA loads reduced 2.0650 log10 copies/ml (t=3.8733), 2.9146 log10 copies/ml (t=7.6741) and 2.4315 log10 copies/ml (t=5.8202) from the baseline at week 0 in the 13 patients in the high group, and reduced 1.1522 log10 copies/ml (t = 2.8937), 1.4189 log10 copies/ml (t=2.4422) and 1.1167 log10 (t=1.1261) in the 8 patients of the low group. However, there was no significant difference between the early viral response rate (EVR) and the end of treatment viral response rate (ETVR) of the two groups. In the high group, the white blood cell count was lower at 24 weeks than the base line (t=2.4700), and the blood platelet count was lower both at 24 and 48 weeks than the base line (t=2.3273 and t=3.6149). CONCLUSIONS: PEG-IFN alfa-2a can effectively reduce HCV RNA loads in patients with HCV-/HIV co-infection, and the inhibition rate in patients with higher CD4 lymphocyte counts is better. The EVR and ETVR of the two groups of patients show similar results after the treatment. PEG-IFN alfa-2a can reduce the white blood cell counts and the blood platelet counts in the peripheral blood.

[Pyr1]-Apelin-13 delivery via nano-liposomal encapsulation attenuates pressure overload-induced cardiac dysfunction.

Nanoparticle-mediated sustained delivery of therapeutics is one of the highly effective and increasingly utilized applications of nanomedicine. Here, we report the development and application of a drug delivery system consisting of polyethylene glycol (PEG)-conjugated liposomal nanoparticles as an efficient in vivo delivery approach for [Pyr1]-apelin-13 polypeptide. Apelin is an adipokine that regulates a variety of biological functions including cardiac hypertrophy and hypertrophy-induced heart failure. The clinical use of apelin has been greatly impaired by its remarkably short half-life in circulation. Here, we investigate whether [Pyr1]-apelin-13 encapsulation in liposome nanocarriers, conjugated with PEG polymer on their surface, can prolong apelin stability in the blood stream and potentiate apelin beneficial effects in cardiac function. Atomic force microscopy and dynamic light scattering were used to assess the structure and size distribution of drug-laden nanoparticles. [Pyr1]-apelin-13 encapsulation in PEGylated liposomal nanocarriers resulted in sustained and extended drug release both in vitro and in vivo. Moreover, intraperitoneal injection of [Pyr1]-apelin-13 nanocarriers in a mouse model of pressure-overload induced heart failure demonstrated a sustainable long-term effect of [Pyr1]-apelin-13 in preventing cardiac dysfunction. We concluded that this engineered nanocarrier system can serve as a delivery platform for treating heart injuries through sustained bioavailability of cardioprotective therapeutics.

Polyvinylpyrrolidone microneedles enable delivery of intact proteins for diagnostic and therapeutic applications.

We present a method of fabricating microneedles from polyvinylpyrrolidone (PVP) that enables delivery of intact proteins (or peptides) to the dermal layers of the skin. PVP is known to self-assemble into branched hollow fibers in aqueous and alcoholic solutions; we utilized this property to develop dissolvable patches of microneedles. Proteins were dissolved in concentrated PVP solution in both alcohol and water, poured into polydimethylsiloxane templates shaped as microneedles and, upon evaporation of solvent, formed into concentric, fibrous, layered structures. This approach of making PVP microneedles overcomes problems in dosage, uniform delivery and stability of protein formulation as compared to protein-coated metallic microneedles or photopolymerized PVP microneedles. Here we characterize the PVP microneedles and measure the delivery of proteins into skin. We show that our method of fabrication preserves the protein conformation. These microneedles can serve as a broadly useful platform for delivering protein antigens and therapeutic proteins to the skin, for example for allergen skin testing or immunotherapy.

Efficient gene delivery of primary human cells using peptide linked polyethylenimine polymer hybrid.

Polyethylenimine (PEI) based polymers are efficient agents for cell transfection. However, their use has been hampered due to high cell death associated with transfection thereby resulting in low efficiency of gene delivery within the cells. To circumvent the problem of cellular toxicity, metal binding peptides were linked to PEI. Eight peptide-PEI derivatives were synthesized to improve cell survival and transfection efficiency. TAT linked PEI was used as a control polymer. Peptides linked with PEI amines formed nanogels as shown by electron microscopy and atomic force microscopic measurements. Polymers were characterized by spectroscopic methods and their ability to form complexes with plasmids was tested using electrophoretic studies. These modifications improved polymer biocompatibility as well as cell survival markedly, when compared to PEI alone. A subset of the modified peptide-polymers also showed significantly higher transfection efficiency in primary human cells with respect to the widely used transfection agent, lipofectamine. Study of the underlying mechanism of the observed phenomena revealed lower levels of 'reactive oxygen species' (ROS) in the presence of the peptide-polymers when compared to PEI alone. This was further corroborated with global gene expression analysis which showed upregulation of multiple genes and pathways involved in regulating intracellular oxidative stress.