Quantitative cellular level analysis of mitochondrial DNA 3243A > G mutations in individual tissues from the archival temporal bones of a MELAS patient.
CONCLUSIONS
We could represent the first quantitative analysis of the mutation rate at the cellular level in human inner ear of a patient with MELAS (mitochondrial encephalopathy, lactic acidosis and stroke-like episodes) by combining laser capture microdissection (LCM) and quantitative real time PCR.


OBJECTIVE
We previously reported combining LCM and PCR to isolate mtDNA from the cells of specific tissues within a human archival celloidin-embedded temporal bone section without known otological history. Using this method, we quantitatively analyzed the rate of mtDNA 3243A > G mutation in the inner ear of a MELAS patient, and examined the correlation of the mutation rate at the cellular level and their histopathological condition.


METHODS
We extracted each inner ear organs using LCM from temporal bone sections of a MELAS patient, and studied the mutation rate, which was calculated as the ratio of the amount of mutant mtDNA to the total mtDNA.


RESULTS
We found that the mtDNA mutation rate was high in spiral ganglion cells and the saccular macula, but was comparatively low in hair cells of the organ of Corti, the stria vascularis and the facial nerve. With the exception of the stria vascularis, there was a good correlation between the mutation rate and the histological findings.
Koda
Hiroko
H
Department of Otolaryngology, Tokyo Metropolitan Health and Medical Treatment Corporation Okubo Hospital, Tokyo. kouda-oto@ohkubohospital.jp
Kimura
Yurika
Y
Ishige
Ikuo
I
Eishi
Yoshinobu
Y
Iino
Yukiko
Y
Kitamura
Ken
K
D008267:Acoustic Maculae / Q000473:pathology; D000328:Adult; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D018450:Disease Progression; D007758:Ear, Inner / Q000473:pathology*; D005154:Facial Nerve / Q000473:pathology; D005260:Female; D006198:Hair Cells, Auditory / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000473:pathology; D006801:Humans; D017241:MELAS Syndrome / Q000235:genetics* / Q000473:pathology; D042282:Microdissection; D009925:Organ of Corti / Q000473:pathology; D016133:Polymerase Chain Reaction; D012444:Saccule and Utricle / Q000473:pathology; D013136:Spiral Ganglion / Q000473:pathology; D013316:Stria Vascularis / Q000473:pathology; D013701:Temporal Bone / Q000473:pathology*
D004272:DNA, Mitochondrial