Association of the 4 g/5 g polymorphism of plasminogen activator inhibitor-1 gene with sudden sensorineural hearing loss. A case control study
1 Division of Allergy-Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, 676 N. St Clair street #14028, Chicago, IL, 60611, USA
2 Kyung Hee University, College of Medicine, Seoul, Korea
3 University of Tennessee, College of Medicine, Memphis, TN, USA
4 University of Modena, Modena, Italy
5 University of Ferrara, Ferrara, Italy
BMC Ear, Nose and Throat Disorders 2012, 12:5 doi:10.1186/1472-6815-12-5Published: 6 June 2012
The 5 G/5 G genotype of PAI-1 polymorphism is linked to decreased plasminogen activator inhibitor-1 (PAI-1) levels and it has been suggested that lower PAI-1 levels may provide protective effects on inflammation, local microcirculatory disturbance, and fibrotic changes, which are likely associated with development of sudden sensorineural hearing loss (SSNHL).
The association of the 4 G/5 G PAI-1 polymorphism with the development and clinical outcome of SSNHL is evaluated via a case control study. 103 patients with SSNHL and 113 age and sex-matched controls were enrolled at University of Ferrara, Italy and hearing loss outcome was measured at least 3 months after the onset of hearing loss. DNA was isolated from peripheral blood using the QIAamp kit and the 4 G/5 G polymorphism in the −675 promoter region was genotyped with an allele-specific PCR. Genotype distribution was tested in patients and compared to controls by chi-square and odd-ratio analysis. The codominant and recessive models were used for the multiple logistic regression analyses of the PAI-1 gene allele.
In this population, 5 G/5 G genotype had a two-time lower frequency in SSNHL patients compared to healthy controls (15.5% vs 30.1%) and was associated with decreased odds compared to 4 G/5 G genotype (OR 0.37, 95% CI 0.19-0.75, p = 0.005). In addition, the patients with 5 G/5 G genotype showed a trend of more than 2 times higher ratio of hearing recovery (> 20 dB) after systemic corticosteroid treatment compared to 4 G/5 G genotype (OR 2.3, 95% CI 0.32 - 16.83, p = 0.39), suggesting a better clinical outcome.
The 5 G/5 G genotype of PAI-1 may be associated with a reduced risk of SSNHL in the Italian population.