Many hydrophobic small molecules are available to regulate gene expression and other cellular functions. Locally restricted application of such molecules in the central nervous system (CNS) would be desirable in many experimental and therapeutic settings, but is limited by a lack of innocuous vehicles able to load and easily deliver hydrophobic cargo. Here, we tested the potential for diblock copolypeptide hydrogels (DCH) to serve as such vehicles. In vitro tests on loading and release were conducted with cholesterol and the anti-cancer agent, temozolomide (TMZ). Loading of hydrophobic cargo modified DCH physical properties such as stiffness and viscosity, but these could readily be tuned to desired ranges by modifying DCH concentration, amino acid composition or chain lengths. Different DCH formulations exhibited different loading capacities and different rates of release. For example, comparison of different DCH with increasing alanine contents showed corresponding increases in both cargo loading capacity and time for cargo release. In vivo tests were conducted with tamoxifen, a small synthetic hydrophobic molecule widely used to regulate transgene expression. Tamoxifen released from DCH depots injected into healthy or injured CNS efficiently activated reporter gene expression in a locally restricted manner in transgenic mice. These findings demonstrate the facile and predictable tunability of DCH to achieve a wide range of loading capacities and release profiles of hydrophobic cargos while retaining CNS compatible physical properties. In addition, the findings show that DCH depots injected into the CNS can efficiently deliver small hydrophobic molecules that regulate gene expression in local cells.

Structured Abstract Purpose The purpose of this study was to investigate the relationship between health literacy and overall medication nonadherence, unintentional nonadherence, and intentional nonadherence. Limited health literacy may be associated with worse diabetes outcomes, but the literature shows mixed results and mechanisms remain unclear. Medication adherence is associated with diabetes outcomes and may be a mediating factor. Distinguishing between unintentional and intentional nonadherence may elucidate the relationship between health literacy and nonadherence in patients with type 2 diabetes. Methods Cross-sectional study of 208 patients with type 2 diabetes recruited from a primary care clinic in St. Louis, MO. Information was obtained from written questionnaire and patient medical records. Bivariate and multivariable regression were used to examine predictors of medication nonadherence. Results The majority of patients in the study were low-income, publicly insured, and African American, with limited health literacy and a high school/GED education or less. In multivariable models, limited health literacy was significantly associated with increased unintentional nonadherence, but not intentional nonadherence. Conclusions Results suggest differences in factors affecting intentional and unintentional nonadherence. The findings also suggest interventions are needed to decrease unintentional nonadherence among patients with type 2 diabetes and limited health literacy. Efforts to address unintentional medication nonadherence among patients with type 2 diabetes with limited health literacy may improve patient health.

Large numbers of cells will be required for successful embryonic stem cell (ESC)-based cellular therapies or drug discovery, thus raising the need to develop scaled-up bioprocesses for production of ESCs and their derived progeny. Traditionally, ESCs have been propagated in adherent cultures in static flasks on fibroblasts layers in serum-containing medium. Direct translation of two-dimensional flatbed cultures to large-scale production of the quantities of cells required for therapy simply by increasing the number of dishes or flasks is not practical or economical. Here, we describe successful scaled-up production of ESCs on microcarriers in a stirred culture system in a serum-free medium. Cells expanded on CultiSpher S, Cytodex 3, and Collagen microcarriers showed superior cell-fold expansions of 439, 193, and 68, respectively, without excessive agglomeration, compared with 27 in static culture. In addition, the ESCs maintained their pluripotency after long-term culture (28 days) in serum-free medium. This is the first time mESCs have been cultured on microcarriers without prior exposure to serum and/or fibroblasts, while also eliminating the excessive agglomeration plaguing earlier studies. These protocols provide an economical, practical, serum-free means for expanding ESCs in a stirred suspension bioprocess.

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