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Significance of kallikrein-kinin system in otitis media with effusion
Abstract:
Significance of the kallikrein-kinin system in the pathogenesis of otitis media with effusion (OME) was evaluated by prekallikrein level, kallikrein activity, and concentration of high molecular weight (HMW) kininogen in 45 middle ear effusions (MEEs, 38 serous and seven mucoid). All MEEs had varying prekallikrein levels (73.1 +/- 127.5 relative fluoro units [RFU]), and the mean value in serous effusions (82.2 RFU) was much higher than that in mucoid effusions (23.0 RFU). Hydrolytic activity of kallikrein in serous effusions was 18.0 +/- 27.9 RFU, and was significantly higher than that in mucoid effusions (8.0 +/- 4.2 RFU, p less than 0.05). Concentration of HMW kininogen in serous effusions was 51.2 +/- 72.77% of plasma value, but it could not be detected in any mucoid effusions. Analysis of protein composition by polyacrylamide gel electrophoresis indicates that plasma protein that has leaked into the middle ear is a major component of MEEs. The kallikrein-kinin system would be active in serous effusions, and liberated bradykinin enhances vascular permeability in the middle ear mucosa, leading to profuse plasma leakage, which characterizes the component of serous effusions. On the other hand, this system would almost be consumed in mucoid effusions.
Insights
The kallikrein-kinin system is active in serous middle ear effusions, contributing to plasma leakage. This system is largely consumed in mucoid effusions, indicating different pathogenesis mechanisms for otitis media with effusion.
Area of Science:
- Biochemistry
- Otolaryngology
- Pathophysiology
Background:
- Otitis media with effusion (OME) is a common condition with complex pathogenesis.
- The role of the kallikrein-kinin system (KKS) in middle ear effusion (MEE) formation is not fully understood.
Purpose of the Study:
- To investigate the significance of the KKS in the pathogenesis of OME.
- To evaluate prekallikrein levels, kallikrein activity, and high molecular weight (HMW) kininogen concentration in MEEs.
Main Methods:
- Analysis of 45 MEEs (38 serous, 7 mucoid) for KKS components.
- Measurement of prekallikrein levels and kallikrein activity using relative fluoro units (RFU).
- Quantification of HMW kininogen concentration relative to plasma levels.
- Protein composition analysis via polyacrylamide gel electrophoresis.
Main Results:
- Prekallikrein levels and kallikrein activity were significantly higher in serous MEEs compared to mucoid MEEs.
- HMW kininogen was detected in serous MEEs but not in mucoid MEEs.
- Plasma proteins were identified as a major component of MEEs, suggesting leakage.
Conclusions:
- The KKS is active in serous MEEs, with bradykinin likely increasing vascular permeability and plasma leakage.
- The KKS appears to be consumed in mucoid MEEs, suggesting a different pathological pathway.
- These findings highlight the differential involvement of the KKS in the pathogenesis of serous versus mucoid OME.