Transition from static culture to stirred tank bioreactor for the allogeneic production of therapeutic discogenic cell spheres.

BACKGROUND: Culturing cells as cell spheres results in a tissue-like environment that drives unique cell phenotypes, making it useful for generating cell populations intended for therapeutic use. Unfortunately, common methods that utilize static suspension culture have limited scalability, making commercialization of such cell therapies challenging. Our team is developing an allogeneic cell therapy for the treatment of lumbar disc degeneration comprised of discogenic cells, which are progenitor cells expanded from human nucleus pulposus cells that are grown in a sphere configuration. METHODS: We evaluate sphere production in Erlenmeyer, horizontal axis wheel, stirred tank bioreactor, and rocking bag format. We then explore the use of ramped agitation profiles and computational fluid dynamics to overcome obstacles related to cell settling and the undesired impact of mechanical forces on cell characteristics. Finally, we grow discogenic cells in stirred tank reactors (STRs) and test outcomes in vitro (potency via aggrecan production and identity) and in vivo (rabbit model of disc degeneration). RESULTS: Computation fluid dynamics were used to model hydrodynamic conditions in STR systems and develop statistically significant correlations to cell attributes including potency (measured by aggrecan production), cell doublings, cell settling, and sphere size. Subsequent model-based optimization and testing resulted in growth of cells with comparable attributes to the original static process, as measured using both in vitro and in vivo models. Maximum shear rate (1/s) was maintained between scales to demonstrate feasibility in a 50 L STR (200-fold scale-up). CONCLUSIONS: Transition of discogenic cell production from static culture to a stirred-tank bioreactor enables cell sphere production in a scalable format. This work shows significant progress towards establishing a large-scale bioprocess methodology for this novel cell therapy that can be used for other, similar cell therapies.

Analysis of chlamydia contacts and the look-back interval at a UK sexual health clinic.

Guidance on contact tracing in Chlamydia trachomatis (CT) is limited. CT contacts data over 12 months (1 December 2018-29 November 2019) at a UK sexual health clinic were analysed to determine the appropriateness of the currently recommended six-month 'look-back' interval. Age and sex of CT contacts were associated with clinical outcomes. Subgroups of 100 CT positive/negative contacts (each N = 100) were randomly selected. The relationship between time since sexual intercourse with the index case (Last Sexual Intercourse; LSI) and CT positivity was examined; suitability of varying look-back intervals was explored. Of 891 CT contacts (mean age = 25.0 years, 66.2% men), 66.9% tested positive for CT. Positive CT contacts were significantly younger (23.8 ± 6.8 years vs. 27.4 ± 9.1, p < 0.001) and more often women (36.4% vs. 28.5%, p = 0.018) than negative contacts. In the subgroups, the Mann-Whitney U test revealed no significant difference between the LSI of positive and negative contacts (p = 0.081). 95% of positive CT contacts (N = 82) were captured within a hypothetical three-month look-back interval. While most CT positive contacts were captured within three months, they appeared to remain proportionately represented beyond this point. Although this supports current guidelines, further research should investigate whether CT contacts involved in longer look-back intervals may require disproportionately greater resources to trace.

Design of experiment (DOE) applied to artificial neural network architecture enables rapid bioprocess improvement.

Modern bioprocess development employs statistically optimized design of experiments (DOE) and regression modeling to find optimal bioprocess set points. Using modeling software, such as JMP Pro, it is possible to leverage artificial neural networks (ANNs) to improve model accuracy beyond the capabilities of regression models. Herein, we bridge the gap between a DOE skill set and a machine learning skill set by demonstrating a novel use of DOE to systematically create and evaluate ANN architecture using JMP Pro software. Additionally, we run a mammalian cell culture process at historical, one factor at a time, standard least squares regression, and ANN-derived set points. This case study demonstrates the significant differences between one factor at a time bioprocess development, DOE bioprocess development and the relative power of linear regression versus an ANN-DOE hybrid modeling approach.

HIV control in postpartum mothers: a turbulent time.

We conducted an audit looking at the management of HIV-positive women in the postpartum period. We found that of the women with a previous AIDS-defining condition or a CD4 count <350 cells/µL, 83% were correctly continued on antiretroviral therapy (ART) and 84.1% of these had good virological control. ART was correctly stopped in 100% of women who had always had a CD4 count >500 cells/µL. A significant finding from our audit was that all of the women who had poor virological control or stopped ART against medical advice had social issues or self-reported depression. The main recommendation was to extend the pregnancy multidisciplinary team (MDT) meeting to include the 12-month postpartum period to offer support to women to try to improve treatment outcomes.

Cystic kidney diseases: many ways to form a cyst.

Renal cysts are a common radiological finding in both adults and children. They occur in a variety of conditions, and the clinical presentation, management, and prognosis varies widely. In this article, we discuss the major causes of renal cysts in children and adults with a particular focus on the most common genetic forms. Many cystoproteins have been localized to the cilia centrosome complex (CCC). We consider the evidence for a universal 'cilia hypothesis' for cyst formation and the evidence for non-ciliary proteins in cyst formation.