Intracellular release of 17-β estradiol from cationic polyamidoamine dendrimer surface-modified poly (lactic-co-glycolic acid) microparticles improves osteogenic differentiation of human mesenchymal stromal cells.
ABSTRACT Human bone marrow mesenchymal stromal cells (MSCs) are considered a potential cell source for MSC-based bone regeneration, but improvements in the proliferation and differentiation capacity of MSCs are necessary for practical applications. Estrogen effectively improves MSC capabilities and has strong potential as a regulator of MSCs. The aim of this study was to develop a delivery system that provides intracellular release of estrogen and test its ability to improve osteogenic differentiation of MSCs. Biodegradable poly (lactic-co-glycolic acid) (PLGA) microparticles were developed that entrap 17-β estradiol (E2) and provide intracellular release of E2. The results show that we can prepare PLGA particles with efficient loading of E2 and maintain release of E2 up to 7 days. Surface modifying E2-loaded PLGA particles with cationic polyamidoamine dendrimers enabled increased uptake by human MSCs. Human MSC uptake of the E2-loaded PLGA particles significantly upregulates osteogenic differentiation markers of alkaline phosphatase and osteocalcin. In conclusion, cationic-modified PLGA particles can serve as a tool for intracellular delivery of estrogen to effectively execute estrogen regulation of MSCs. This approach has the potential to improve the osteogenic capabilities of MSCs and to develop appropriate environments of implantation for MSC-based bone tissue engineering.
Article: In vitro evaluation of the direct effect of estradiol on human osteoblasts (HOB) and human mesenchymal stem cells (h-MSCs).[show abstract] [hide abstract]
ABSTRACT: Estrogen may increase the proliferation of osteoblasts depending upon their differentiation stage. Our objective was to test the hypothesis that estradiol could stimulate the proliferation of primary human osteoblast (HOB) cells or human mesenchymal stem cells (h-MSCs). To test this hypothesis, we investigated two synthetic estradiol preparations: (a) a commercially available one (in clinical use) whose effect was evaluated using MTT assay, trypan blue cell counts and total protein assays; (b) a novel synthetic preparation (not in clinical use) using Alamar Blue assays and scanning electron microscopy (SEM). Commercial estradiol increased HOB proliferation in a concentration-dependant manner between 1 nM and 8 nM reaching significance at a concentration of 8 nM (p<0.001). Small doses of 1 nM and 2 nM increased h-MSC proliferation (p<0.001) but higher doses had no effect. All novel synthetic estradiol preparations decreased HOB proliferation (p<0.001) whereas no direct effect was observed on h-MSCs. Commercial estradiol appears to induce proliferation of HOBs, although its effects on h-MSCs appears to be highly dose-dependent and requires further investigation.Injury 09/2006; 37 Suppl 3:S33-42. · 1.98 Impact Factor
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ABSTRACT: A technology has been developed to isolate a developmentally and phenotypically homogeneous population of pluripotent human mesenchymal stem cells (hMSCs) from adult bone marrow and mitotically expand these cells in culture. These hMSCs have osteoblasts as one of their potential developmental end-stage phenotypes, and, in addition to their osteogenic potential, these hMSCs synthesize and secrete a variety of macromolecules that are known regulators of osteoclast differentiation and activity. In this review, data are presented that demonstrate the phenotypic and developmental homogeneity of the cells in hMSC cultures, as well as their ability to differentiate along multiple phenotypic pathways and serve as regulatory cells for hematopoietic and bone-resorbing cells. In addition, a logic and preliminary data are presented that support the use of hMSCs in the prevention and treatment of age-related and postmenopausal osteoporosis. Since hMSC differentiation and phenotypic expression are controlled by regulatory molecules synthesized and secreted by a variety of local and systemic mechanisms, the issue of whole organism physiology is addressed in considering tissue engineering logics.Advanced drug delivery reviews 09/1998; 33(1-2):3-14. · 11.96 Impact Factor
Article: Phenotypic changes of adult porcine mesenchymal stem cells induced by prolonged passaging in culture.[show abstract] [hide abstract]
ABSTRACT: The in vitro culture of porcine bone marrow-derived mesenchymal stem cells (MSCs) was used for the investigation of adult stem cell biology. Isolated porcine MSCs possessed the ability to proliferate extensively in an antioxidants-rich medium containing 5% fetal bovine serum (FBS). Greater than 40 serial MSC passages and 100 cell population doublings have been recorded for some MSC batches. Early and late passage MSCs were defined here as those cultures receiving less than 5 trypsin passages and more than 15 trypsin passages, respectively. Consistent with their robust ability to proliferate, both the early and late passage MSCs expressed the cell-cycle promoting enzyme p34cdc2 kinase. Late MSCs, however, exhibited certain features reminiscent of cellular aging such as actin accumulation, reduced substrate adherence, and increased activity of lysosomal acid beta-galactosidase. Early MSCs retained the multipotentiality capable of chondrogenic, osteogenic, and adipogenic differentiation upon induction in vitro. In contrast, late MSCs were only capable of adipogenic differentiation, which was greatly enhanced at the expense of the osteochondrogenic potential. Along with these changes in multipotentiality, late MSCs expressed decreased levels of the bone morphogenic protein (BMP-7) and reduced activity of alkaline phosphatase. Late MSCs also exhibited attenuated synthesis of the hematopoietic cytokines granulocyte colony-stimulating factor (G-CSF), leukemia inhibitory factor (LIF), and stem cell factor (SCF). The long-term porcine MSC culture, thus, provides a model system to study the molecular interplay between multiple MSC differentiation cascades in the context of cellular aging.Journal of Cellular Physiology 12/2005; 205(2):194-201. · 3.87 Impact Factor