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Sinyov et al. mtDNA mutations in buccal epithelium

m.13513G>A m.12315G>A m.1555A>G m.3256C>T m.3336T>C

Figure 1: The heteroplasmy level of mitochondrial genome mutations in whole blood and buccal epithelium from 134 donors. Error bars
show the standard error. mtDNA: mitochondrial DNA

P = [(h - N)/(M - N)]*100%, RESULTS

Where: P is the percentage heteroplasmy; h is the The investigated sample of 134 participants was
peak height of the investigated nucleotide; N is the divided by gender and age. All the examined individuals
peak height of the investigated nucleotide, relevant to had their IMT measured. A total of 35 of the donors
the presence of 100% of normal alleles in a sample; were men, with a mean ± standard deviation (SD) age
M is the peak height of the investigated nucleotide, of 61 ± 10 years and an IMT of 0.84 ± 0.21 mm. The
relevant to the presence of 100% of mutant alleles in remaining 97 donors were women, with a mean ± SD
a sample. age of 61 ± 11 years and an IMT of 0.79 ± 0.41 mm.

Statistical processing of the data was carried out using During the quantitative assessment of the mutant allele
the software package SPSS version 22.0 (SPSS Inc., of mitochondrial genome, data on the heteroplasmy
USA). [14] Independent samples were assessed using levels in buccal epithelial and whole blood cells were
t-tests and Mann-Whitney U-tests, and correlation obtained [Figure 1]. The obtained data were analyzed
analyses were also conducted. Differences were using the t-test for independent samples.
considered significant at P < 0.05.
Significant differences in the heteroplasmy level of
Next, the possibility that buccal epithelium might be the mitochondrial genome mutation m.3256C>T were
equivalent to whole blood for the genetic diagnosis of found between buccal epithelial and whole blood cells
atherosclerosis was assessed. For this purpose the (P = 0.01). However, there were no differences in the
threshold heteroplasmy level of mutations was used, mutations m.13513G>A (P = 0.48), m.3336T>C (P =
after which in individuals atherosclerotic plaques were 0.65), m.12315G>A (P = 0.13), and m.1555А>G (P =
detected or antiatherogenic effect of these single 0.23).
nucleotide substitutions manifests. [14] According to
the data, previously obtained by the members of The difference between average heteroplasmy levels
our laboratory, [11] the threshold heteroplasmy level of the investigated mutations did not exceed 5% and
of mtDNA mutations for atherosclerotic plaques in the standard error in a range of cases was higher
human carotid arteries for atherogenic mutations is: than the mean level. This is probably connected to the
17.5% for m.1555А>G; 6.5% for m.3336T>C; 7.5% for fact that each individual has a different heteroplasmy
m.12315G>A; and 15.5% for m.3256C>T. For the anti- level of mtDNA mutations, and that heteroplasmy
atherogenic mutation m.13513G>A, the threshold level levels significantly differ within an investigated
of heteroplasmy is 32.5%. sample. Therefore, it is unlikely that the impact of the
Vessel Plus ¦ Volume 1 ¦ September 26, 2017 147