[Does therapeutic membrane plasmapheresis increase protein synthesis?]

The objective of the investigation was to assess whether therapeutic membrane plasmapheresis accelerates protein synthesis. To this end pseudouridine (PSI), a modified nucleoside was investigated which provides information on the tRNA turnover and thus indirectly also on protein synthesis. The authors made 10 plasmapheresis on a A 2008 PF monitor with Plasmaflux P2 filters which they use to exchange 1 plasma volume of the patients. Laboratory indicators were investigated one day before plasmapheresis, on the day of plasmapheresis and during its course, and on the 1st, 2nd and possibly 3rd day after plasmapheresis. They revealed that the clearance of the plasma filter for PSI (0.41 +/- 0.04 ml/s, arithmetical mean +/- SEM) did not differ significantly from the filtration rate (0.49 +/- 0.01 ml/s, p = 0.15). As compared with the initial examination (0.49 +/- 0.06 ml/s) on the first day after plasmapheresis as a result of reduced glomerular filtration rate the renal clearance of PSI was reduced (0.33 +/- 0.05, p less than 0.01). PSI serum concentrations were therefore expressed as the serum PSI/serum creatinine ratio. This ratio was, as compared with the initial examination (80.4 +/- 4.8 nmol/mumol), raised midway during the procedure (100.8 +/- 8.6, p much less than 0.05) and after its termination (132.3 +/- 6.1, p much less than 0.01). The increase was not due to disintegration of cells or dietary factors. The rise of the serum PSI/serum creatinine ratio was due to a more rapid tRNA turnover and thus provided evidence that therapeutic membrane plasmapheresis accelerates protein synthesis.