PROTEIN PROFILE OF HUMAN PERILYMPH - IN SEARCH OF MARKERS FOR THE DIAGNOSIS OF PERILYMPH FISTULA AND OTHER INNER-EAR DISEASE

Recent developments in high-resolution two-dimensional polyacrylamide gel electrophoresis, combined with amino acid sequencing and computer- assisted image analysis, have allowed separation of approximately 100 proteins and identification and quantitation of some 30 proteins in hu man perilymph. The majority of proteins were found to be present in pe rilymph at levels in basic agreement with the total protein gradient b etween perilymph and plasma (1:35). However, several striking differen ces were observed: (1) beta 2-transferrin, known to be absent from nor mal plasma but present in cerebrospinal fluid, was detected in perilym ph at a concentration roughly equal to that in cerebrospinal fluid; an d (2) two high-density lipoprotein-associated apolipoproteins - apo D (formerly PLS:33) and apo J or NA1 and NA2 (formerly PSL:29/30), the l atter showing identity with SP40/40, or cytolysis inhibitor-were found to be present at concentrations 1 to 2 orders of magnitude higher whe n examined in terms Of total protein and to be comparable with or high er than plasma levels when examined in terms of absolute concentration s. The functional significance of the extremely high levels of the two apolipoproteins is not known at this time. An attempt was made to use beta 2-transferrin, as well as apo D and apo J (NA1/NA2), as markers for the diagnosis of perilymph fistula, one of the most controversial and challenging problems for the otologist today. It was determined th at the technique is indeed applicable when relatively pure fistula sam ples are analyzed. Limitations and potential improvements of the techn ique are discussed. In addition, the potential usefulness of two-dimen sional polyacrylamide gel electrophoresis in other pathologic conditio ns of the inner ear is discussed briefly.