Mitochondrial Haplogroups and Control Region Polymorphisms in Age-Related Macular Degeneration: A Case-Control Study

Background: Onset and development of the multifactorial disease age-related macular degeneration (AMD) are highly interrelated with mitochondrial functions such as energy production and free radical turnover. Mitochondrial dysfunction and overproduction of reactive oxygen species may contribute to destruction of the retinal pigment epithelium, retinal atrophy and choroidal neovascularization, leading to AMD. Consequently, polymorphisms of the mitochondrial genome (mtDNA) are postulated to be susceptibility factors for this disease. Previous studies from Australia and the United States detected associations of mitochondrial haplogroups with AMD. The aim of the present study was to test these associations in Middle European Caucasians. Methodology/Principal Findings: Mitochondrial haplogroups (combinations of mtDNA polymorphisms) and mitochondrial CR polymorphisms were analyzed in 200 patients with wet AMD (choroidal neovascularization, CNV), in 66 patients with dry AMD, and in 385 controls from Austria by means of multiplex primer extension analysis and sequencing, respectively. In patients with CNV, haplogroup H was found to be significantly less frequent compared to controls, and haplogroup J showed a trend toward a higher frequency compared to controls. Five CR polymorphisms were found to differ significantly in the two study populations compared to controls, and all, except one (T152C), are linked to those haplogroups. Conclusions/Significance: It can be concluded that haplogroup J is a risk factor for AMD, whereas haplogroup H seems t

Nucleotide excision repair is not induced in human embryonic lung fibroblasts treated with environmental pollutants.

The cellular response to genotoxic treatment depends on the cell line used. Although tumor cell lines are widely used for genotoxicity tests, the interpretation of the results may be potentially hampered by changes in cellular processes caused by malignant transformation. In our study we used normal human embryonic lung fibroblasts (HEL12469 cells) and tested their response to treatment with benzo[a]pyrene (B[a]P) and extractable organic matter (EOM) from ambient air particles <2.5 µm (PM2.5) collected in two Czech cities differing in levels and sources of air pollution. We analyzed multiple endpoints associated with exposure to polycyclic aromatic hydrocarbons (PAHs) including the levels of bulky DNA adducts and the nucleotide excision repair (NER) response [expression of XPE, XPC and XPA genes on the level of mRNA and proteins, unscheduled DNA synthesis (UDS)]. EOMs were collected in the winter and summer of 2011 in two Czech cities with different levels and sources of air pollution. The effects of the studied compounds were analyzed in the presence (+S9) and absence (-S9) of the rat liver microsomal S9 fraction. The levels of bulky DNA adducts were highest after treatment with B[a]P, followed by winter EOMs; their induction by summer EOMs was weak. The induction of both mRNA and protein expression was observed, with the most pronounced effects after treatment with B[a]P (-S9); the response induced by EOMs from both cities and seasons was substantially weaker. The expression of DNA repair genes was not accompanied by the induction of UDS activity. In summary, our results indicate that the tested compounds induced low levels of DNA damage and affected the expression of NER genes; however, nucleotide excision repair was not induced

Maternal Diet Quality and the Health Status of Newborns

The maternal diet during pregnancy affects neonatal health status. The objective of this study was to assess the nutritional quality of the maternal diet, and its contamination by persistent organic pollutants (POPs), in pregnant women living in two areas of the Czech Republic with different levels of air pollution, and subsequently to assess the relationship of these two factors with birth weight and neonatal oxidative stress. To determine the level of oxidative stress, 8-isoprostane concentrations in umbilical cord plasma were measured. The overall nutritional quality of the maternal diet was not optimal. Of the nutritional factors, protein intake proved to be the most significant showing a positive relationship with birth weight, and a negative relationship with the oxidative stress of newborns. Dietary contamination by persistent organic pollutants was low and showed no statistically significant relationship with birth weight. Only one of the 67 analyzed POPs, namely the insecticide dichlorodiphenyltrichloroethane (DDT), showed a statistically significant positive relationship with the level of neonatal oxidative stress

Relative levels of XPE, XPC and XPA mRNAs.

<p>The levels of mRNAs were analyzed after the 6 h treatment of HEL12469 cells with benzo[a]pyrene (B[a]P) and extractable organic matter (EOM) in the absence (–S9) and presence (+S9) of the microsomal S9 fraction. Mean ± SD values from three independent cell treatments are shown, asterisks denote a significant (p<0.05) increase/decrease of mRNA levels. The baseline mRNA level after treatment of the cells with DMSO is represented by a bold horizontal line.</p

PAH content in extractable organic matter (EOM) from individual samplings.

*<p>Significant differences (p<0.001) in PAH concentrations between EOMs from Prague-summer vs. Ostrava-summer and Prague-winter vs. Ostrava-winter.</p

Final concentration of benzo[a]pyrene (B[a]P) in culture media after treatment of the cells with various concentrations of EOM.

<p>Final concentration of benzo[a]pyrene (B[a]P) in culture media after treatment of the cells with various concentrations of EOM.</p

Western blotting analyses of the levels of XPE, XPC and XPA proteins.

<p>Protein expression was measured after the 24 h treatment of HEL12469 cells with benzo[a]pyrene (B[a]P) and extractable organic matter (EOM) in the absence (–S9) and presence (+S9) of the microsomal S9 fraction. A representative result of two independent experiments is shown. Amido Black-stained proteins were used as a loading control.</p

Relative levels of XPE, XPC and XPA proteins in lysates of HEL12469 cells.

<p>The cells were treated with B[a]P and EOMs for 24 h. The data represent mean protein levels relative to the control sample from two independent experiments. P–W = Prague-winter, O–W = Ostrava-winter, P–S = Prague-summer, O–S = Ostrava-summer.</p

Relative levels of unscheduled DNA synthesis (UDS).

<p>UDS in HEL12469 cells was studied after 24 h treatment with benzo[a]pyrene (B[a]P) and extractable organic matter (EOMs) in the absence (–S9) and presence (+S9) of the S9 microsomal fraction. Mean ± SD UDS values relative to the DMSO-treated control are shown, asterisks denote a significant (p<0.05) increase/decrease in the activity of UDS. The baseline levels of UDS in cells treated with DMSO is represented by a bold horizontal line. Each mean UDS value is based on the analysis of 700–2500 cells.</p