Expansion of human mesenchymal stromal cells on microcarriers: growth and metabolism.

Adult stem cells, or mesenchymal stromal cells (MSCs), are of great potential for cell therapy and tissue-engineering applications. However, for therapeutic use, these cells need to be isolated from tissue or a biopsy and efficiently expanded, as they cannot be harvested in sufficient quantities from the body. In our opinion, efficient expansion of MSCs can be achieved in a microcarrier-based cultivation system. This study selected a suitable microcarrier for human bone marrow-derived stromal cells (HBMSCs), optimized cell-seeding strategies by varying serum concentrations, and optimized dynamic expansion of the HBMSCs in a microcarrier-based spinner flask cultivation system by applying various feeding regimes. Cytodex 1 microcarriers in combination with a low-serum concentration (0-5%) in the medium resulted in the highest seeding efficiency for the HBMSCs. Subsequently, significant expansion of the HBMSCs on these carriers has been observed. The highest number of HBMSCs population doublings (4.8 doublings) was obtained by a combination of 50% medium refreshment combined with addition of 30% medium containing microcarriers every 3 days. Exponential cell growth was observed for at least 9 days after seeding, provided that sufficient nutrients (such as glucose) were present, metabolite concentrations (such as ammonia) were kept below growth-inhibitory concentrations and adequate surface area was present for the cells. After dynamic expansion of the HBMSCs, the cells retained their differentiation potential and their cell surface markers, indicating that HBMSCs expansion on Cytodex 1 microcarriers did not alter the phenotypic properties of the cells.

Expansion of mesenchymal stem cells using a microcarrier-based cultivation system: growth and metabolism.

For the continuous and fast expansion of mesenchymal stem cells (MSCs), microcarriers have gained increasing interest. The aim of this study was to evaluate the growth and metabolism profiles of MSCs, expanded in a microcarrier-based cultivation system. We investigated various cultivation conditions to expand goat mesenchymal stem cells on Cytodex 1 microcarriers. These conditions differed in feeding regime, i.e. the addition of fresh proliferation medium, with or without new microcarriers. For all conditions, cell attachment, cell proliferation, energy source consumption, metabolite production, and cell distribution on the microcarriers were studied. Attachment efficiencies of 40% were obtained followed by successful expansion up to 15 cultivation days. Depending on the feeding regime, an exponential growth, stationary growth, and decline growth phase could be distinguished. Addition of 30% fresh medium containing microcarriers every three days showed the longest continuous proliferation of goat MSCs on microcarriers. This feeding regime has the advantage that metabolites, such as ammonia, are diluted and that new energy sources, such as glucose and glutamine, and additional surface area are provided to the cells. In addition, by adding extra microcarriers a more homogenous cell distribution on the microcarriers is obtained as a result of bead-to-bead transfer. A correlation between nutrient consumption, metabolite production and cell growth was observed. The decreasing yield of lactate from glucose over time indicated a possible shift in cellular metabolism.

[Influencing factors of different durations of behavioral therapy in in-patients with anxiety disorders]. / Bedingungsfaktoren unterschiedlicher Behandlungsdauer bei Angststörungen im Rahmen stationärer Verhaltenstherapie.

In this study, the influencing factors of different durations of in-patient therapy were examined. We investigated 1173 patients with anxiety disorders who were treated in the psychosomatic clinic of Bad Pyrmont with behavioural therapy. Patients with anxiety disorders have an average treatment duration of 52.4 days with a minimum of less than one week and a maximum of more than five months. The duration of treatment depends on the one hand on sociodemographic variables such as age, marital status, partnership, residential status, and professional activity, but not on gender or education. The duration of treatment also depends on factors of severity of the disorder, such as the number of in-patient or psychotherapeutic treatments, duration of disorder and disability, and the number of psychiatric diagnoses, but not on the number of somatic diagnoses. There is a positive correlation between duration of treatment and effect of therapy as well as recovery of fitness for work.