Summary

Regolamento nutrienti alimentando in continuo per l'espansione su larga scala di cellule di mammifero in Spheroids

Published: September 25, 2016
doi:

Summary

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.

Abstract

In this demonstration, spheroids formed from the β-TC6 insulinoma cell line were cultured as a model of manufacturing a mammalian islet cell product to demonstrate how regulating nutrient levels can improve cell yields. In previous studies, bioreactors facilitated increased culture volumes over static cultures, but no increase in cell yields were observed. Limitations in key nutrients such as glucose, which were consumed between batch feedings, can lead to limitations in cell expansion. Large fluctuations in glucose levels were observed, despite the increase in glucose concentrations in the media. The use of continuous feeding systems eliminated fluctuations in glucose levels, and improved cell growth rates when compared with batch fed static and SSB culture methods. Additional increases in growth rates were observed by adjusting the feed rate based on calculated nutrient consumption, which allowed the maintenance of physiological glucose over three weeks in culture. This method can also be adapted for other cell types.

Introduction

Al fine di generare un gran numero di cellule umane vitali e funzionali per il trapianto, la regolamentazione delle condizioni di coltura è imperativo. L'esaurimento delle sostanze nutritive, con accumulo di scorie metaboliche sono i principali contributori alla senescenza e metaboliche modifiche che riducono la qualità del prodotto cellulare 1 3. Questa procedura illustra un metodo per cellule di mammifero coltura in sferoidi usando un bioreattore agitata combinato con un sistema di alimentazione tasso di perfusione regolata per regolare il glucosio in un intervallo fisiologico 4 per tutta la durata della cultura. Ai fini di questi studi, l'intervallo fisiologico è stato definito come tra 100 e 200 mg / dl. Gli stessi metodi possono essere usati per regolare altri nutrienti e rifiuti metabolici come lattato.

culture statiche in piccoli volumi (1 – 30 ml) sono tipicamente utilizzati in ambiente di laboratorio per mantenere e differenziare le linee cellulari per experimefini ntale. Cellulare passaging viene eseguita con cambi completi medie come necessario ad intervalli regolari. Più terreno di coltura "convenzionale" ha una concentrazione di glucosio alto (450 mg / dl per DMEM utilizzato in questi studi) per consentire meno frequenti cambiamenti medi senza il rischio di limitazioni nutrizionali. Tuttavia, questo metodo batch alimentazione richiede ancora manipolazione frequente, introduce variabilità nell'ambiente cellulare, e aumenta il rischio di contaminazione 5 9. Bioreattori sospensione agitata (SSB) fornire una migliore miscelazione e diminuito movimentazione 3,10 20, ma, come le culture statiche, richiedono cambiamenti medi manuali che contribuiscono alle fluttuazioni potenzialmente dannosi nei livelli di prodotti nutrienti e rifiuti. Perfusione alimentazione di culture SSB riduce questi problemi infusione continua e la rimozione del mezzo, ma grandi cambiamenti nei livelli di nutrienti a causa della crescita delle cellule rimangono un problema. L'uso di un ra alimentazione adjustedte dai calcoli di uso di sostanze nutritive in base ai requisiti delle cellule stimato in grado di fornire l'ambiente cellulare stabile necessaria per ottimizzare la vitalità delle cellule e funzionare 21 24.

Vi è un grande corpo di letteratura che descrive i metodi per scalabili culture SSB di cellule di mammifero in particolare per la cultura e l'espansione delle cellule pluripotenti 25 32, con gli altri focalizzata su isolotto (beta), le cellule 17,33,34, o la produzione di prodotti biologici 24, 35 38. Molti di questi tipi di cellule indagati può essere coltivata nelle culture sferoidali, e procedure specifiche per il tipo di cella utilizzato dovrebbe essere ottimizzato prima di implementare un sistema di alimentazione continua. In questa dimostrazione, un metodo di alimentazione di perfusione è stato usato per espandere una linea cellulare beta cresciuto come sferoidi in un bioreattore agitato 39 -. 43 Il metodo qui descritto fornisce unsemplice implementazione di alimentazione adeguamenti tariffari sulla base di misure di glucosio off-line per ottenere condizioni di coltura mirati. Regolazione della velocità di avanzamento con questo metodo per mantenere un livello di glucosio fisiologica è indicata ai rendimenti delle cellule aumenta. Le cellule di mammiferi dipendono da un nutriente chiave, glucosio, per la produzione di energia, quindi l'uso di questa linea cellulare rappresenta un modello per molte cellule di mammifero in coltura 44. Inoltre, questa linea esemplifica l'ulteriore complessità delle cellule beta, che sono sensibili ad elevati livelli di glucosio croniche 45. Per questo studio, le cellule beta-TC6 sono stati autorizzati a formare sferoidi nella cultura per approssimare le dimensioni medie delle isole di Langerhans in vivo. Il sistema di bioreattore perfusione 17 19,21,46 con una velocità di avanzamento regolata al glucosio consumo, ha determinato il mantenimento di condizioni fisiologiche e rendimenti più elevati cellulari senza cambiamenti di viabilità.

Protocol

1. Cell Line e manutenzione Ottenere cellule beta-TC6 (o altra linea cellulare di mammifero aderenti desiderato). In preparazione per lo studio, la cultura, il passaggio, e crioconservare le cellule secondo le istruzioni del fornitore. 2. Montare il sistema di alimentazione continua NOTA: La progettazione del sistema di alimentazione continua del seguente metodo è basata su sistemi analoghi descritti in letteratura 17 – …

Representative Results

I livelli di glucosio medio e fluttuazioni Limitare cellulare espansione in Culture standard SSB I livelli di glucosio fluttuano nelle culture statiche e culture SSB per tutto il periodo di coltura 3. Queste fluttuazioni intensificano con l'aumentare il numero delle cellule durante il periodo di coltura di 21 giorni ed erano quasi identici in entrambe le culture statiche e SSB. Queste osservazioni sono presentati nella nostra precedente pubblicazione 3.</…

Discussion

Generazione di prodotti cellulari di mammiferi per la produzione di agenti biologici e terapie cellulari richiede la cultura e monitoraggio di cellule di mammifero in grande scala 55 58. Inoltre, queste applicazioni richiedono condizioni di coltura definite e validate. Semplicemente aumentando il volume delle cellule che utilizzano tecnologie di ricerca non si incontreranno tutti questi requisiti. variazioni medie manuali provocando fluttuazioni di sostanze nutritive e l'accumulo d…

Disclosures

The authors have nothing to disclose.

Acknowledgements

The authors thank Michael Garwood and Sam Stein for their helpful comments, and Kristen M. Maynard for assistance with manuscript preparation.

Materials

Name of Reagent/ Equipment Company Catalog Number / Link Comments/Description
BTC-6 Cells ATCC, Manassas, VA CRL-11506 Mouse Insulinoma cell line (adherent cell type)
DPBS No CA, No Mg Invitrogen, Carlsbad, CA 14190-144 https://www.lifetechnologies.com/order/catalog/product/14190144?ICID=search-14190144
Dulbecco's Modified Eagles Medium Invitrogen, Carlsbad, CA See below for product numbers 
DMEM High Glucose (500mM) Invitrogen, Carlsbad, CA 11965-092 http://www.lifetechnologies.com/order/catalog/product/11965092
DMEM Low Glucose (100mM) Invitrogen, Carlsbad, CA 11885-084 http://www.lifetechnologies.com/order/catalog/product/11885084 (note that this medium already contains pyruvate)
L-gultamine Invitrogen, Carlsbad, CA 25030081 http://www.lifetechnologies.com/order/catalog/product/25030081?ICID=search-product
Sodium Pyruvate Invitrogen, Carlsbad, CA 11360070 https://www.lifetechnologies.com/order/catalog/product/11360070?ICID=search-product
Heat Inactivated Porcine Serum Gibco – Life Technologies 10082147 http://www.lifetechnologies.com/order/catalog/product/10082147
Trypsin-EDTA Invitrogen, Carlsbad, CA 25200056 https://www.lifetechnologies.com/order/catalog/product/25200056?ICID=search-product
T-150 Tissue Culture Treated Flasks Corning, Corning, NY 430825 http://catalog2.corning.com/LifeSciences/en-US/Shopping/ProductDetails.aspx?productid=430825(Lifesciences)
&categoryname=
NuAire Cell culture incubator Princeton, MN US Autoflow , Any water-jacketed CO2 regulating cell culture incubator could be used
Centrifuge Sorvall RT 7 (Any similar benchtop centrifuge may be used)
Refrigerator Any laboratory refrigerator could be used (a small table-top version was used for these studies)
1L Glass Bottle Corning, Corning, NY 1395-1L Any vendor could be used http://catalog2.corning.com/LifeSciences/en-US/Shopping/ProductDetails.aspx?productid=1395-1L(Lifesciences)
&categoryname=
2L Glass Bottle Corning, Corning, NY 1395-2L Any vendor could be used
250 ml stirred bioreactors  Corning, Corning, NY 4500-250 http://catalog2.corning.com/LifeSciences/en-US/Shopping/ProductDetails.aspx?productid=4500-250(Lifesciences)
&categoryname=
Stir Plate Fisher Scientific 11-496-104A Any incubator safe stir-plate can be used, any vendor
Tissue Culture Dishes 100mm Diameter Nunc, Rochester, NY (Fisher Scientific) 1256598  Any vendor could be used (ordered through Fisher Sci)
FALCON 50 ml Conical Tubes Falcon, San Jose, CA 1256598 Any vendor could be used
Delran Plastic Used for Custom Parts McMaster Carr Various Any material of choice could be used, but Deran is chosen because it is autoclave safe, non-reactive, and easy to machine, http://www.mcmaster.com/#acetal-homopolymer-sheets/=rjrcac
Stainless Steel Pipe for custom lids McMaster Carr Various Any vendor could be used, http://www.mcmaster.com/#standard-stainless-steel-tubing/=rjrd91
Custom Modified Delran Bioreactor Lids for Continuous Feeding Custom made  Not aware of any vendors producing a similar product
Custom Modified Glass Bottle Lids for Continuous feeding Custom made  Some vendors (eg. Fischer Sci, Corning) make similar products in the links below
Masterflex Digital Peristaltic Pump Cole Parmer, Vernon Hills, IL EW-77919-25 Any precision peristaltic pump could be used, http://www.coleparmer.com/Product/L_S_Eight_Channel_Four_Roller_
Cartridge_Pump_System_115_230
_VAC/EW-77919-25
PVDF Tubing Connectors (various) Cole Parmer, Vernon Hills, IL see link Any vendor could be used, http://www.coleparmer.com/Category/Cole_Parmer_PVDF_Premium
_Luer_Fittings/55889
Pharmed BPT Tubing L/S 16 Cole Parmer, Vernon Hills, IL WU-06508-16 Any vendor could be used, http://www.coleparmer.com/Product/Masterflex_PharMed_BPT_Tubing
_L_S_13_25/WU-06508-16
Pharmed BPT Tubing L/S 14 Cole Parmer, Vernon Hills, IL WU-06508-14 Any vendor could be used, http://www.coleparmer.com/Product/Masterflex_PharMed_BPT_Tubing
_L_S_13_25/WU-06508-14
Pharmed BPT Tubing L/S 13 Cole Parmer, Vernon Hills, IL WU-06508-13 Any vendor could be used, http://www.coleparmer.com/Product/Masterflex_PharMed_BPT_Tubing
_L_S_13_25/WU-06508-13
Millipore Millex GP PES membrane 0.22ul sterile syringe filter (used for venting, and medium filtration) Fisher Scientific SLGP033RS Any vendor could be used
25ml Graduated Pipette Fisher Scientific 13-678-11 Any vendor could be used, and various sizes may be used
Pipetter Fisher Scientific 13-681-15E Any vendor, or similar product could be used
Hemocytometer Fisher Scientific 02-671-6 Any vendor, or similar product could be used
Trypan Blue Gibco – Life Technologies 15250-061 Any vendor, or similar product could be used, https://www.lifetechnologies.com/order/catalog/product/15250061
Inverted Light Microscope Leica Any vendor, or similar product could be used
One Touch Ultra Blood Glucose Meter Fisher Scientific 22-029-293  Any vendor, or similar product could be used (eg. Bayer)
One Touch Ultra-Strips Fisher Scientific 22-029-292  Any vendor, or similar product could be used (eg. Bayer)

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Cite This Article
Weegman, B. P., Essawy, A., Nash, P., Carlson, A. L., Voltzke, K. J., Geng, Z., Jahani, M., Becker, B. B., Papas, K. K., Firpo, M. T. Nutrient Regulation by Continuous Feeding for Large-scale Expansion of Mammalian Cells in Spheroids. J. Vis. Exp. (115), e52224, doi:10.3791/52224 (2016).

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