In Vivo Degradation of Crosslinked Hyaluronic Acid Fillers by Exogenous Hyaluronidases.

Background: An advantage of hyaluronic acid (HA)-based fillers is reversibility.

Objective: To evaluate the ability of 2 hyaluronidases to degrade 3 HA-based fillers using a novel in vivo model.

Materials And Methods: Rats were injected with 3 HA fillers (HYC-24L+, VYC-20L, and RES-L) to create a projecting bolus.

Rheological Properties and In Vivo Performance Characteristics of Soft Tissue Fillers.

Background: Physicochemical properties and performance in nonclinical animal models can provide insights into soft tissue filler performance.

Objective: To evaluate the in vivo performance of fillers with different compositions and physicochemical properties.

Materials And Methods: Physicochemical properties were measured in vitro.

Skin extracellular matrix stimulation following injection of a hyaluronic acid-based dermal filler in a rat model.

Background: Hyaluronic acid-based dermal fillers have gained rapid acceptance for treating facial wrinkles and deep tissue folds. Although their space-filling properties are well understood, this study evaluates the cellular and molecular changes in skin, as a secondary effect, following injection of a commercially available, 24-mg/ml, cross-linked hyaluronic acid-based filler (HYC-24L+) in a rodent model.

Methods: Sprague-Dawley rats, aged 2 to 4 months, were injected intradermally with 20 μl of HYC-24L+ using a linear threading technique and followed to 12 weeks after injection.

Approaches to avoid immune responses induced by repeated subcutaneous injections of allogeneic umbilical cord tissue-derived cells.

Background: Cellular treatments for repairing diseased tissues represent a promising clinical strategy. Umbilical cord tissue-derived cells (UTC) are a unique source of cells with a low immunogenic profile and potential for tissue repair. By using UTC from miniature swine, we previously demonstrated that despite their low immunogenic phenotype, UTC could induce an immune response under certain inflammatory conditions and after multiple subcutaneous (SC) injections.

Immunogenicity of umbilical cord tissue derived cells.

Umbilical cord tissue provides a unique source of cells with potential for tissue repair. Umbilical cord tissue-derived cells (UTCs) are MHC class I (MHCI) dull and negative for MHC class II (MHCII), but can be activated to increase MHCI and to express MHCII with IFN-gamma stimulation. Mesenchymal stem cells with similar characteristics have been inferred to be nonimmunogenic; however, in most cases, immunogenicity was not directly assessed.

Cells isolated from umbilical cord tissue rescue photoreceptors and visual functions in a rodent model of retinal disease.

Progressive photoreceptor degeneration resulting from genetic and other factors is a leading and largely untreatable cause of blindness worldwide. The object of this study was to find a cell type that is effective in slowing the progress of such degeneration in an animal model of human retinal disease, is safe, and could be generated in sufficient numbers for clinical application. We have compared efficacy of four human-derived cell types in preserving photoreceptor integrity and visual functions after injection into the subretinal space of the Royal College of Surgeons rat early in the progress of degeneration.

A cell encapsulation device for studying soluble factor release from cells transplanted in the rat brain.

The transplantation of a variety of naturally occurring and genetically modified cell types has been shown to be an effective experimental method to achieve sustained delivery of therapeutic molecules to specific target areas in the brain. To acquire a better understanding of dosing, implant mechanism of action, and how certain cell types affect remodeling of central nervous system (CNS) tissue, a refillable cell encapsulation device was developed for introducing cells into the brain while keeping them physically isolated from contact with brain tissue with a semipermeable membrane. The stereotactically placed device consists of a hollow fiber membrane (HFM), a polyurethane grommet with watertight cap that snaps into a precisely drilled hole in the rat skull, and a removable cell-containing insert.

Comparison of pure and mixed populations of human fetal-derived neural progenitors transplanted into intact adult rat brain.

We examined the influence of initial graft composition on the number, type, and distribution of human progenitor cells after transplantation into the anterior subventricular zone (SVZa) of normal adult rats. The grafted populations were derived from 19-week-old human cortical tissue grown under adherent conditions in the presence of fibroblast growth factor (FGF) and from a subpopulation of nestin-expressing cells, isolated using negative immunoselection methods, which exhibited properties of neural progenitors. Identical numbers of each were transplanted and the number and location of engrafted cells were compared 4 weeks later.