Consequences of trace metal variability and supplementation on Chinese hamster ovary (CHO) cell culture performance: A review of key mechanisms and considerations

Trace metals are supplied to chemically-defined media (CDM) for optimal Chinese hamster ovary (CHO) cell culture performance during the production of monoclonal antibodies and other therapeutic proteins. However, lot-to-lot and vendor-to-vendor variability in raw materials consequently leads to an imbalance of trace metals that are supplied to CDM. This imbalance can yield detrimental effects rooted in several primary mechanisms and pathways including oxidative stress, apoptosis, lactate accumulation, and unfavorable glycan synthesis. Recent research endeavors involve supplying zinc, copper, and manganese to CDM in excess to further maximize culture productivity and product quality. These treatments significantly impact critical quality attributes and furthermore highlight the degree to which trace metal availability can affect CHO cell culture performance. This review highlights the role of trace metal variability, supplementation, and interplay on key cellular mechanisms responsible for overall culture performance and the production and quality of therapeutic proteins.     

Tissue scaffold surface patterning for clinical applications

Patterned scaffold surfaces provide a platform for highly defined cellular interactions, and have recently taken precedence in tissue engineering. Despite advances in patterning techniques and improved tissue growth, no clinical studies have been conducted for implantation of patterned biomaterials. Four major clinical application fields where patterned materials hold great promise are antimicrobial surfaces, cardiac constructs, neurite outgrowth, and stem cell differentiation. Specific examples include applications of patterned materials to (i) counter infection by antibiotic resistant bacteria, (ii) establish proper alignment and contractile force of regrown cardiac cells for repairing tissue damaged by cardiac infarction, (iii) increase neurite outgrowth for central nervous system wound repair, and (iv) host differentiated stem cells while preventing reversion to a pluripotent state. Moreover, patterned materials offer unique advantages for artificial implants which other constructs cannot. For example, by inducing selective cell adhesion using topographical cues, patterned surfaces present cellular orientation signals that lead to functional tissue architectures. Mechanical stimuli such as modulus, tension, and material roughness are known to influence tissue growth, as are chemical stimuli for cell adhesion. Scaffold surface patterns allow for control of these mechanical and chemical factors. This review identifies research advances in scaffold surface patterning, in light of pressing clinical needs requiring organization of cellular interactions.     

Analysis of short-term variation and long-term drift during reagent kit lot change in an NABL accredited clinical biochemistry laboratory

BackgroundKit lot change in clinical biochemistry labs leads to variations in patient results. This study planned to identify variations during 60 reagent lot changes in our laboratory during the period from June 2018 to May 2019.MethodsA statistical analysis was performed to identify the difference between patient samples results variations and QC results. The long term drift was analyzed using a regression test.ResultsThere was a significant difference between the patient and QC results in 16.7% of reagent lot changes. Moreover, the extent of variation in QC results was 3.3%. No long-term drift was seen in three analytes which were studied using regression analysis.ConclusionsOur results showed that, during reagent kit lot change, along with QC material, the patient samples should also be run in order to identify the variation. However, this practice is presently ignored by most of the laboratories. There was no accumulated effect in our laboratory due to reagent kit lot change.