Secretion of erythropoietin from microencapsulated rat kidney cells: preliminary results

Rat kidney epithelial cells were microencapsulated within alginate-poly(L)lysine-alginate membrane. The microencapsulated cells were incubated using a culture media containing cobalt and another without cobalt. The viability was measured by trypan blue exclusion test. Secretion of erythropoietin (EPO) was measured by radioimmunoassay (RIA). Viability of free cells was 53%. The viability of microencapsulated cells increased to 72% after 12 days of incubation and remained at this level. Samples of the culture media were collected every 2 days for RIA. Samples within the microcapsules were collected by breaking the microcapsules open. RIA of these samples showed the following for the media containing cobalt. Between day 16 and day 32 the concentrations of EPO were 5.3 mU/ml inside and 18.3 mU/ml outside the microcapsule. The medium from the same number of free cells contained 21.2 mU/ml of EPO. Culture media without cobalt collected during the same period contained 1.8 mU/ml inside and 9.9 mU/ml outside the microcapsules. The free cell culture with this media during the same period contained 8.3 mU/ml.