Prostaglandin Production by Human Peripheral Blood Monocytes Changes with in Vitro Differentiation

To investigate the influence of in vitro culture on prostaglandin (PG) production, human monocyte enriched peripheral blood mononuclear cells were isolated and incubated on gelatin-coated plates. On days zero, five and eleven of culture, the cells were examined microscopically and the production of PGF1 alpha, PGE2, PGD2, F metabolite (PGFM) and E metabolite (PGEM) were measured by radioimmunoassay. Differences in PG output were analyzed using the Wilcoxon and Friedman tests. Freshly isolated human peripheral blood monocytes produced mainly PGE2. In vitro, however, PGE2 production decreased from 196 (48-288) fmol/10(6) cells per 3h on day zero of culture to 28 (6-51) on day eleven (p = 0.04); median (range), n = 7. Prostaglandin D2 and PGEM output decreased similarly, but these differences failed to reach significance. Prostaglandin F2 alpha and PGFM output, on the other hand, increased from 32 and 19 fmol/10(6) cells per 3h, respectively, on day zero of culture to 127 (p < 0.05) and 58 (p = 0.01) on day eleven. Changes in PG output were associated with in vitro differentiation as evidenced by changes in cellular morphology. These result suggest that differentiation of human peripheral blood monocytes in vitro is accompanied by a shift in PG output from PGE2 and PGD2, towards PGF2 alpha.