Mitochondrial DNA alteration in obstructive sleep apnea

Abstract

BackgroundObstructive Sleep Apnea (OSAS) is a disease associated with the increase of cardiovascular risk and it is characterized by repeated episodes of Intermittent Hypoxia (IH) which inducing oxidative stress and systemic inflammation. Mitochondria are cell organelles involved in the respiratory that have their own DNA (MtDNA). The aim of this study was to investigate if the increase of oxidative stress in OSAS patients can induce also MtDNA alterations.Methods46 OSAS patients (age 59.27 ± 11.38; BMI 30.84 ± 3.64; AHI 36.63 ± 24.18) were compared with 36 control subjects (age 54.42 ± 6.63; BMI 29.06 ± 4.7; AHI 3.8 ± 1.10). In blood cells Content of MtDNA and nuclear DNA (nDNA) was measured in OSAS patients by Real Time PCR. The ratio between MtDNA/nDNA was then calculated. Presence of oxidative stress was evaluated by levels of Reactive Oxygen Metabolites (ROMs), measured by diacron reactive oxygen metabolite test (d-ROM test).ResultsMtDNA/nDNA was higher in patients with OSAS than in the control group (150.94 ± 49.14 vs 128.96 ± 45.8; p = 0.04), the levels of ROMs were also higher in OSAS subjects (329.71 ± 70.17 vs 226 ± 36.76; p = 0.04) and they were positively correlated with MtDNA/nDNA (R = 0.5, p < 0.01).ConclusionsIn OSAS patients there is a Mitochondrial DNA damage induced by the increase of oxidative stress. Intermittent hypoxia seems to be the main mechanism which leads to this process.

The relationship between increased oxidative stress and visual field defect progression in glaucoma patients with sleep apnoea syndrome

“…This study builds upon recent findings that patients with SAS have a high incidence of glaucoma (Lin et al 2013) and elevated oxidative stress and dROM levels (Lacedonia et al 2015), in comparison with healthy controls. These findings prompted us to perform a comparison of patients with glaucoma that did and not have SAS.…”

“…) and elevated oxidative stress and dROM levels (Lacedonia et al. ), in comparison with healthy controls. These findings prompted us to perform a comparison of patients with glaucoma that did and not have SAS.…”

Regulation of mitochondrial genome replication by hypoxia: The role of DNA oxidation in D-loop region

“…The effect of hypoxia on mtDNA replication and mitochondrial biogenesis is also complex and may depend on many factors, including sex specificity [57]. Although some cell types respond to hypoxia by reducing their mitochondrial biogenesis and mtDNA content [58–60], mtDNA copy number is reported to increase under hypoxic conditions in many other tissues, including brain, liver, heart, placenta, sperm and blood cells [23–25, 61–67]. Hypoxia, like many other factors that affect mitochondrial biogenesis, utilizes mitochondria-generated ROS as second messengers [68–71].…”

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