Combined Application of Prototype Ultrasound and BSA-Loaded PLGA Particles for Protein Delivery.

PURPOSE: To develop an in vitro culture system for tissue engineering to mimic the in vivo environment and evaluate the applicability of ultrasound and PLGA particle system. METHODS: For tissue engineering, large molecules such as growth factors for cell differentiation should be supplied in a controlled manner into the culture system, and the in vivo microenvironment need to be reproduced in the system for the regulation of cellular function. In this study, portable prototype ultrasound with low intensity was devised and tested for protein release from bovine serum albumin (BSA)-loaded poly(lactic-co-glycolic acid) (PLGA) particles. RESULTS: BSA-loaded PLGA particles were prepared using various types of PLGA reagents and their physicochemical properties were characterized including particle size, shape, or aqueous wetting profiles. The BSA-loaded formulation showed nano-ranged size distribution with optimal physical stability during storage period, and protein release behaviors in a controlled manner. Notably, the application of prototype ultrasound with low intensity influenced protein release patterns in the culture system containing the BSA-loaded PLGA formulation. The results revealed that the portable ultrasound set controlled by the computer could contribute for the protein delivery in the culture medium. CONCLUSIONS: This study suggests that combined application with ultrasound and protein-loaded PLGA encapsulation system could be utilized to improve culture system for tissue engineering or cell regeneration therapy.

Synergistic Effect of Growth Factor Releasing Polymeric Nanoparticles and Ultrasound Stimulation on Osteogenic Differentiation.

Mesenchymal stem cells (MSCs) have been extensively used in the tissue regeneration therapy. Ex vivo therapy with well-differentiated osteogenic cells is known as an efficient treatment for musculoskeletal diseases, including rheumatoid diseases. However, along with its high cost, the current therapy has limitations in terms of restoring bone regeneration procedures. An efficient process for the cell differentiation to obtain a large number of functionalized osteogenic cells is necessary. Therefore, it is strongly recommended to develop strategies to produce sufficient numbers of well-differentiated osteogenic cells from the MSCs. In general, differentiation media with growth factors have been used to facilitate cell differentiation. In the present study, the poly (lactic-co-glycolic acid) (PLGA) nanoparticles incorporating the growth factors were included in the media, resulting in releasing growth factors (dexamethasone and ß-glycerophosphate) in the media in the controlled manner. Stable growth and early differentiation of osteogenic cells were achieved by the PLGA-based growth factor releasing system. Moreover, low intensity pulsed ultrasound was applied to this system to induce cell differentiation process. The results revealed that, as a biomarker at early stage of osteogenic cell differentiation, Lamin A/C nuclear protein was efficiently expressed in the cells growing in the presence of PLGA-based growth factor reservoirs and ultrasound. In conclusion, our results showed that the ultrasound stimulation combined with polymeric nanoparticles releasing growth factors could potentially induce osteogenic cell differentiation.

Regression of asymptomatic intracranial arterial stenosis by aggressive medical management with a lipid-lowering agent.

OBJECTIVE: The incidence rate of stroke as a result of intracranial arterial stenosis (ICAS) is higher in Asian countries than in the West. We aimed to analyze the regression, lack of change, or progression of asymptomatic ICAS after the administration of rosuvastatin and associated factors. METHODS: The patients who had undergone computed tomography angiography (CTA) at our hospital and had been diagnosed with ICAS with no ischemic event in the stenosed vascular territory were included in the study. They were administered 20mg of rosuvastatin per day. After a follow-up period of at least 6 months after treatment, the patients were examined using CTA again and the clinical information and imaging results were analyzed. RESULTS: In total, 48 patients were diagnosed with asymptomatic ICAS. During the final follow-up examination, it was found that the stenotic lesion regressed in 30 patients, whereas it remained unchanged or progressed without any adverse effects in 18 patients. In univariate analysis, the regressed group showed significantly higher differences in the levels of total cholesterol and low-density lipoprotein (LDL) between their initial and final values (both, p=0.031 for both). In the multivariate analysis, a significantly higher difference in the levels of LDL between its initial and final measurement was seen in the regressed group (p=0.035, odds ratio(OR) 3.9). CONCLUSIONS: Rosuvastatin was found to have better lipid-lowering effects for total cholesterol and particularly LDL in patients whose ICAS had regressed. We concluded that rosuvastatin administration can be recommended for the treatment of patients with asymptomatic ICAS.