No abstract

Amniotic fluid (AF) possesses anti-inflammatory, anti-microbial and regenerative properties that make it attractive for use in clinical applications. The goals of this study were to assess the feasibility of collecting AF from full-term pregnancies and to evaluate non-cellular and cellular properties of AF for clinical applications. Donor informed consent and medical histories were obtained from pregnant women scheduled for C-sections and infectious disease testing was performed the day of collection. AFs were evaluated for total volume, fluid chemistries, total protein, and hyaluronic acid (HA) levels. AF was also assessed with quantitative antibody arrays, cellular content and for an ability to support angiogenesis. Thirty-six pregnant women consented and passed donor screening to give birth tissue. AF was successfully collected from 17 individuals. Median AF volumes were 70 mL (range 10-815 mL; n = 17). Fluid chemistries were similar, but some differences were noted in HA levels and cytokine profiles. Cytokine arrays revealed that an average of 304 ± 20 of 400 proteins tested were present in AF with a majority of cytokines associated with host defense. AF supported angiogenesis. Epithelioid cells were the major cell type in AF with only a minor population of lymphoid cells. Cultures revealed a highly proliferative population of adherent cells capable of producing therapeutic doses of mesenchymal stromal cells (MSCs). These findings showed that significant volumes of AF were routinely collected from full-term births. AF contained a number of bioactive proteins and only a rare population of MSCs. Variations noted in components present in different AFs, warrant further investigations to determine their relevance for specific clinical applications.

Background Efforts are underway to eliminate fetal bovine serum (FBS) from mammalian cell cultures for clinical use. An emerging viable replacement option for FBS is human platelet lysate (PL) either as a plasma (PL-P) or serum (PL-S) based product. Study Design and Methods Nine industrial scale PL-S manufacturing runs (i.e. lots) were performed that consisted of an average volume of 24.6±2.2 liters of pooled platelet-rich-plasma (PRP) units that were obtained from apheresis donors. Manufactured lots were compared by evaluating various biochemical and functional test results. Comprehensive cytokine profiles of PL lots and product stability testing was performed. Global gene expression profiles of Mesenchymal Stromal Cells (MSCs) when cultured with PL-S or PL-P were compared with FBS. Results Electrolyte and protein levels were relatively consistent among all PL-S lots with only slight variations in glucose and calcium levels. All nine lots were as good as or better than FBS in expanding MSCs. PL-S stored at −80°C remained stable over two years. Quantitative cytokine arrays showed similarities as well as dissimilarities in the proteins present in PL-S. Greater differences in MSC gene expression profiles were attributable to the starting cell source than as to whether PL or FBS were used as culture supplements. Conclusion Using a large-scale standardized method, lot-to-lot variations were noted for industrial scale preparations of PL-S. However, all lots were as good as or better than FBS in supporting MSC growth. Together these data indicate that off-the-shelf PL is a feasible substitute for FBS in MSC cultures.

No abstract

Protons act as neuromodulators and produce significant effects on synaptic transmission. The molecular basis of neuromodulation by extracellular protons is partially explained by their effects on certain neurotransmitter receptors and ion channels. The metabotropic glutamate receptors (mGluRs) are a family of eight receptor subtypes that are widely expressed throughout the mammalian CNS. In this study, the effects of physiologically relevant changes in extracellular pH were examined in mammalian cells expressing the mGluR subtypes: human mGluR1a, mGluR4a, mGluR5d or mGluR8b. The signal transduction coupling properties of mGluR4a and mGluR8b were switched from the adenylate cyclase (G_i) pathway to the phospholipase C (G_q) pathway by coexpression of a promiscuous G protein. Fluorometric imaging plate reader was used to measure changes in cytoplasmic calcium concentrations in response to agonist. Extracellular acidification from pH 8.0 to pH 6.5 progressively diminished mGluR4 responsiveness to the agonists L-glutamate and (2S,1′S,2′R)-2-(carboxycyclopropyl)glycine (L-CCG-I), and this inhibition was characterized by insurmountable antagonism. By comparison, extracellular acidification did not significantly alter mGluR8 responses to agonists. Furthermore, agonist activation of mGluR1a and mGluR5d was virtually unaffected by changes in pH. Because mGluR4 is expressed presynaptically and its activation inhibits the release of neurotransmitters such as glutamate and GABA, we propose that the net effect of proton inhibition of mGluR4 would be to reverse or prevent that suppression of neurotransmitter release. As such, local decreases in pH could have significant effects on the regulation of transmitter release and synaptic tone via modulation of mGluR4.