Culture and Function of Electrofusion-Derived Clonal Insulin-Secreting Cells Immobilized on Solid and Macroporous Microcarrier Beads

In view of the advantages of the bulk production of clonal pancreaticbeta cells, an investigation was made of the growth and insulin secretoryfunctions of an electrofusion-derived cell line (BRIN-BD11) immobilizedon a solid microcarrier, cytodex-1 or a macroporous microcarrier,cultispher-G. For comparison, similar tests were performed usingBRIN-BD11 cells present in single cell suspensions or allowed toform pseudoislets. Similar growth profiles were recorded for eachmicrocarrier with densities of 4.4×10⁵±0.3 cells/ml and4.2×10⁵±0.2 cells/ml achieved using cytodex-1 andcultispher-G, respectively. Cell viability began to decline on day 5 ofculture. Insulin concentration in the culture medium reached a peak of26±2.0 ng/ml and 24±2.2 ng/ml for cells grown oncytodex-1 and cultispher-G, respectively. Cells grown on both types ofmicrocarrier showed a significant 1.5–1.8-fold acuteinsulin-secretory response to 16.7 mmol/l glucose. L-alanine (10 mmol/l) andL-arginine (10 mmol/l) also induced significant 3–4 fold increasesof insulin release. BRIN-BD11 cells immobilized on cytodex-1 or cultispher-Gout-performed single cell suspensions and pseudoislets in terms ofinsulin-secretory responses to glucose and amino acids. A 1.3-fold,2.2-fold and 1.7-fold stimulation of insulin secretion was observed forglucose, L-alanine and L-arginine respectively in single cellsuspensions. Corresponding increases for pseudoislets were1.6–1.8-fold for L-alanine and L-arginine, with no significantresponse to glucose alone. These data indicate the utility ofmicro-carriers for the production of functioning clonal beta cells.