In JoVE (1)
Articles by Kristin J. Voltzke in JoVE
Nutrient Regulation by Continuous Feeding for Large-scale Expansion of Mammalian Cells in Spheroids Bradley P. Weegman1, Ahmad Essawy2, Peter Nash2, Alexandra L. Carlson2, Kristin J. Voltzke3, Zhaohui Geng2, Marjan Jahani2, Benjamin B. Becker2, Klearchos K. Papas4, Meri T. Firpo2 1Radiology, University of Minnesota, 2Medicine, University of Minnesota, 3School of Public Health, University of Minnesota, 4Surgery, University of Arizona Nutrient regulation using continuous growth adjusted feeding improves growth rates of mammalian cell spheroids compared to intermittent batch feeding for cultures in stirred suspension bioreactors. This study demonstrates the methods required for establishing simple adjusted rate fed cultures.
Other articles by Kristin J. Voltzke on PubMed
From Cell Culture to a Cure: Pancreatic β-cell Replacement Strategies for Diabetes Mellitus Regenerative Medicine. Sep, 2012 | Pubmed ID: 22954439 Numerous advances have been made in pancreatic β-cell replacement therapies for diabetes mellitus. While these therapies provide a positive impact and possible cure for the individual recipient, access is limited by availability of donor tissues. The derivation of pluripotent stem cells using efficient differentiation technologies has resulted in the generation of insulin-producing cells with characteristics similar to islet β-cells. Experimental transplantation studies have shown that these cells are capable of reducing hyperglycemia in short-term assays. Novel methodologies that facilitate the neogenesis of β-cells from endogenous hepatic or pancreatic tissue sources are also being investigated as a β-cell replacement strategy. Further research is necessary to protect these transplanted or regenerated cells from diabetic autoimmune pathology.
Nutrient Regulation by Continuous Feeding Removes Limitations on Cell Yield in the Large-scale Expansion of Mammalian Cell Spheroids PloS One. 2013 | Pubmed ID: 24204645 Cellular therapies are emerging as a standard approach for the treatment of several diseases. However, realizing the promise of cellular therapies across the full range of treatable disorders will require large-scale, controlled, reproducible culture methods. Bioreactor systems offer the scale-up and monitoring needed, but standard stirred bioreactor cultures do not allow for the real-time regulation of key nutrients in the medium. In this study, β-TC6 insulinoma cells were aggregated and cultured for 3 weeks as a model of manufacturing a mammalian cell product. Cell expansion rates and medium nutrient levels were compared in static, stirred suspension bioreactors (SSB), and continuously fed (CF) SSB. While SSB cultures facilitated increased culture volumes, no increase in cell yields were observed, partly due to limitations in key nutrients, which were consumed by the cultures between feedings, such as glucose. Even when glucose levels were increased to prevent depletion between feedings, dramatic fluctuations in glucose levels were observed. Continuous feeding eliminated fluctuations and improved cell expansion when compared with both static and SSB culture methods. Further improvements in growth rates were observed after adjusting the feed rate based on calculated nutrient depletion, which maintained physiological glucose levels for the duration of the expansion. Adjusting the feed rate in a continuous medium replacement system can maintain the consistent nutrient levels required for the large-scale application of many cell products. Continuously fed bioreactor systems combined with nutrient regulation can be used to improve the yield and reproducibility of mammalian cells for biological products and cellular therapies and will facilitate the translation of cell culture from the research lab to clinical applications.