Adipose-derived mesenchymal stem cell-incorporated PLLA porous microspheres for cartilage regeneration.

BACKGROUND: In facial plastic surgery, patients with nasal deformity are often treated by rib cartilage transplantation. In recent years, cartilage tissue engineering has developed as an alternative to complex surgery for patients with minor nasal defects via injection of nasal filler material. In this study, we prepared an injectable nasal filler material containing poly-L-lactic acid (PLLA) porous microspheres (PMs), hyaluronic acid (HA) and adipose-derived mesenchymal stem cells (ADMSCs). METHODS: We seeded ADMSCs into as-prepared PLLA PMs using our newly invented centrifugation perfusion technique. Then, HA was mixed with ADMSC-incorporated PLLA PMs to form a hydrophilic and injectable cell delivery system (ADMSC-incorporated PMH). RESULTS: We evaluated the biocompatibility of PMH in vitro and in vivo. PMH has good injectability and provides a favorable environment for the proliferation and chondrogenic differentiation of ADMSCs. In vivo experiments, we observed that PMH has good biocompatibility and cartilage regeneration ability. CONCLUSION: In this study, a injectable cell delivery system was successfully constructed. We believe that PMH has potential application in cartilage tissue engineering, especially in nasal cartilage regeneration.

A silk-based hydrogel containing dexamethasone and lipoic acid microcrystals for local delivery to the inner ear.

Local drug delivery has been exploited recently to treat hearing loss, as this method can both bypass the blood-labyrinth barrier and provide sustained drug release. Combined drug microcrystals (MCs) offer additional advantages for sensorineural hearing loss treatment via intratympanic (IT) injection due to their shape effect and combination strategy. In this study, to endow viscous effects of hydrogels, nonspherical dexamethasone (DEX) and lipoic acid (LA) MCs were incorporated into silk fibroin (SF) hydrogels, which were subsequently administered to the tympanic cavity to investigate their pharmaceutical properties. First, we prepared DEX and LA MCs by a traditional precipitation technique followed by SF hydrogel incorporation (SF+DEX+LA). After characterization of the physicochemical features, including morphology, rheology, and dissolution, both a suspension of combined DEX and LA MCs (DEX+LA) and SF+DEX+LA were administered to guinea pigs by IT injection, after which the pharmacokinetics, biodegradation and biocompatibility were evaluated. To our surprise, compared to the DEX+LA group, the pharmacokinetics of the SF+DEX+LA hydrogel group did not improve significantly, which may be ascribed to their nonspherical shape and deposition effects of the drugs MCs. The cochlear tissue in each group displayed good morphology, with no obvious inflammatory reactions. This combined MC suspension has the clear advantages of no vehicle, easy scale-up preparation, and good biocompatibility and outcomes, which paves the way for practical treatment of hearing loss via local drug delivery.

Influence of meteorological conditions and particulate matter on visual range impairment in Jinan, China.

To understand the influence of aerosol particles and meteorological conditions on visual range in Jinan, the capital of Shandong Province, China, PM(2.5) and PM(10) samples were collected from November 2004 to September 2005. The mass concentrations of PM(2.5) and PM(10), concentrations of water-soluble ions in PM(2.5) and concentrations of black carbon (BC) in the atmosphere were analyzed. The decrease of visual range in Jinan results from the combined influence of PM(2.5), PM(10) and meteorological conditions. For the period studied, the average light extinction coefficient, b(ext), which was estimated from an equation developed by the IMPROVE network was 292 Mm(-1). Ammonium sulfate was the major contributor to visual range impairment, accounting for 41%, while ammonium nitrate, particulate organic matter (POM) and BC made comparable contributions accounting for 20%, 22% and 18%, respectively. This highlights the significance of secondary particles ((NH(4))(2)SO(4), NH(4)NO(3), POM) in visual range impairment in Jinan. The data from this study are also compared with the long-term variations of visual range in Jinan from 1961 to 2005.