Mitochondrial DNA deletions in patients with chronic suppurative otitis media
Arzu Tatar1, Sener Tasdemir2, Ibrahim Sahin2
1Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine, Ataturk University, Erzurum, Turkey. arzutatar@atauni.edu.tr.
Abstract:
The aim of this study was to investigate the 4977 and 7400 bp deletions of mitochondrial DNA in patients with chronic suppurative otitis media and to indicate the possible association of mitochondrial DNA deletions with chronic suppurative otitis media. Thirty-six patients with chronic suppurative otitis media were randomly selected to assess the mitochondrial DNA deletions. Tympanomastoidectomy was applied for the treatment of chronic suppurative otitis media, and the curettage materials including middle ear tissues were collected. The 4977 and 7400 bp deletion regions and two control regions of mitochondrial DNA were assessed by using the four pair primers. DNA was extracted from middle ear tissues and peripheral blood samples of the patients, and then polymerase chain reactions (PCRs) were performed. PCR products were separated in 2 % agarose gel. Seventeen of 36 patients had the heterozygote 4977 bp deletion in the middle ear tissue but not in peripheral blood. There wasn't any patient who had the 7400 bp deletion in mtDNA of their middle ear tissue or peripheral blood tissue. The patients with the 4977 bp deletion had a longer duration of chronic suppurative otitis media and a higher level of hearing loss than the others (p < 0.01). Long time chronic suppurative otitis media and the reactive oxygen species can cause the mitochondrial DNA deletions and this may be a predisposing factor to sensorineural hearing loss in chronic suppurative otitis media. An antioxidant drug as a scavenger agent may be used in long-term chronic suppurative otitis media.
Insights
Mitochondrial DNA deletions, specifically the 4977 bp type, are linked to chronic suppurative otitis media and increased hearing loss. This finding suggests a potential role for mitochondrial DNA deletions in disease progression and hearing impairment.
Area of Science:
- Genetics
- Otolaryngology
- Mitochondrial Biology
Background:
- Chronic suppurative otitis media (CSOM) is a common ear infection.
- Mitochondrial DNA (mtDNA) deletions are implicated in various cellular dysfunctions.
- The association between mtDNA deletions and CSOM requires further investigation.
Purpose of the Study:
- To investigate the presence of 4977 bp and 7400 bp mitochondrial DNA deletions in patients with CSOM.
- To determine the potential association between these mtDNA deletions and the pathogenesis of CSOM.
Main Methods:
- DNA was extracted from middle ear tissues and peripheral blood of 36 CSOM patients.
- Polymerase chain reaction (PCR) was used to detect specific mtDNA deletions (4977 bp and 7400 bp).
- Middle ear tissues and peripheral blood samples were analyzed for mtDNA deletions.
Main Results:
- The 4977 bp mtDNA deletion was found in the middle ear tissue of 17 out of 36 patients, but not in their peripheral blood.
- No patients exhibited the 7400 bp mtDNA deletion in either tissue type.
- Patients with the 4977 bp deletion showed a longer duration of CSOM and higher levels of hearing loss (p < 0.01).
Conclusions:
- The 4977 bp mtDNA deletion is associated with chronic suppurative otitis media.
- This deletion may be a predisposing factor for sensorineural hearing loss in CSOM patients.
- Antioxidant therapies could be considered for managing long-term CSOM and associated hearing loss.
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