DNA Damage/Repair and Polymorphism of the hOGG1 Gene in Lymphocytes of AMD Patients

Oxidative stress is thought to play a role in the pathogenesis of age-related macular degeneration (AMD). We determined the extent of oxidative DNA damage and the kinetics of its removal as well as the genotypes of the Ser326Cys polymorphism of the hOGG1 gene in lymphocytes of 30 wet AMD patients and 30 controls. Oxidative DNA damage induced by hydrogen peroxide and its repair were evaluated by the comet assay and DNA repair enzymes. We observed a higher extent of endogenous oxidative DNA damage and a lower efficacy of its repair in AMD patients as compared with the controls. We did not find any correlation between the extent of DNA damage and efficacy of DNA repair with genotypes of the Ser326Cys polymorphism. The results obtained suggest that oxidative DNA damage and inefficient DNA repair can be associated with AMD and the variability of the hOOG1 gene may not contribute to this association

Kwasy Omega-3 w profilaktyce zwyrodnienia plamki związanego z wiekiem

Zwyrodnienie plamki związane z wiekiem (AMD) jest wiodącą przyczyną utraty widzenia, a możliwości leczenia tego schorzenia są nadal ograniczone. Plamka jest obszarem położonym w centrum siatkówki i odpowiedzialnym za widzenie precyzyjne. Zwyrodnienie plamki związane z wiekiem obejmuje zmiany degeneracyjne w obszarze plamki, takie jak druzy, zaburzenia nabłonka barwnikowego siatkówki oraz obecność neowaskularyzacji podsiatkówkowej. Identyfikacja modyfikowalnych czynników ryzyka wystąpienia AMD może mieć wpływ na poprawę profilaktyki i leczenia tego schorzenia. Jest prawdopodobne, że dieta tłuszczowa ma związek z ryzykiem wystąpienia AMD. Wielonienasycone kwasy tłuszczowe z grupy Omega-3, a zwłaszcza kwas dokozaheksaenowy, są obecne w siatkówce i odgrywają ważną rolę w prawidłowym jej funkcjonowaniu. Im większe spożycie kwasów Omega-3 i ryb, przy obniżonej podaży w diecie kwasu linolenowego, tym większy spadek ryzyka wystąpienia AMD i progresji schorzenia do postaci wysiękowej

Polymorphism of the flap endonuclease 1 gene in keratoconus and Fuchs endothelial corneal dystrophy

Oxidative stress is implicated in the pathogenesis of many diseases, including serious ocular diseases, keratoconus (KC) and Fuchs endothelial corneal dystrophy (FECD). Flap endonuclease 1 (FEN1) plays an important role in the repair of oxidative DNA damage in the base excision repair pathway. We determined the association between two single nucleotide polymorphisms (SNPs), c.-441G>A (rs174538) and g.61564299G>T (rs4246215), in the FEN1 gene and the occurrence of KC and FECD. This study involved 279 patients with KC, 225 patients with FECD and 322 control individuals. Polymerase chain reaction (PCR) and length polymorphism restriction fragment analysis (RFLP) were applied. The T/T genotype of the g.61564299G>T polymorphism was associated with an increased occurrence of KC and FECD. There was no association between the c.-441G>A polymorphism and either disease. However, the GG haplotype of both polymorphisms was observed more frequently and the GT haplotype less frequently in the KC group than the control. The AG haplotype was associated with increased FECD occurrence. Our findings suggest that the g.61564299G>T and c.-441G>A polymorphisms in the FEN1 gene may modulate the risk of keratoconus and Fuchs endothelial corneal dystrophy.peer-reviewe

Estimation of variability of retinal vessel network caused by pathology

Wstęp. W niniejszej pracy omówiono zagadnienie zmienności, czyli plastyczności sieci naczyń krwionośnych siatkówki, związane ze stanami patologicznymi. Wydaje się, że nawet wykształcona w rozwoju osobniczym sieć naczyń siatkówki może ulec zmianom kształtu, a zwłaszcza stopnia rozgałęzienia, zapewne pod wpływem czynników angiogennych wytwarzanych w przebiegu procesów patologicznych. Materiał i metody. Analiza fraktalna fotografii dna oka pozwoliła na wykazanie znamiennych różnic pomiędzy grupą kontrolną a chorymi na retinopatię cukrzycową, retinopatię nadciśnieniową oraz zmiany degeneracyjne plamki żółtej związane z wiekiem (AMD). Wyniki i analizę statystyczną oparto na obliczeniu wymiarów fraktalnych 173 fotografii dna oka pacjentów oraz osób z grupy kontrolnej. Przebadano 38 pacjentów z retinopatią cukrzycową, 31 osób z retinopatią nadciśnieniową, 32 chorych z jaskrą otwartego kąta, 39 pacjentów z AMD oraz 33 osoby z grupy kontrolnej. Wymiar fraktalny jest matematycznym parametrem opisującym stopień skomplikowania analizowanej sieci. Fotografie dna oka przetworzono cyfrowo, znormali-zowano i opracowano matematycznie. Zastosowano box counting method w celu obliczenia wymiarów fraktalnych. Wnioski. Taka analiza pozwala nie tylko na ocenę plastyczności i zmienności oraz stopnia skomplikowania sieci naczyniowej związanej ze stanami patologicznymi, ale umożliwia zastosowanie tej metody w diagnostyce okulistycznej.Background. The present study shows the plasticity of retinal vessel networks connected with pathology. It seems that even in adults, retinal vessel networks can change their shape and arborisation under the influence of angiogenic factors connected with pathological processes. Material and methods. Fractal analysis of photographs of vascular networks revealed significant differences between controls and diabetic retinopathy, hypertensive retinopathy and AMD (age related macular degeneration). The results are based on the analysis and calculations of fractal dimensions of 173 pathological and control photographs of retinal vessels. The following patients were included in the study: 38 diabetic retinopathy, 31 hypertensive retinopathy, 32 open-angle glaucoma, 39 AMD patients and 33 controls. The fractal dimension is the mathematical parameter describing the complexity of the analysed network. The obtained images of retinal vessel networks were digitised, normalised and processed mathematically. The box counting method was used for calculation of fractal dimensions. Conclusions. This analysis allows not only for description of the plasticity and complexity of retinal network as the effect of pathological conditions but also contains the potential to use this kind of analysis for diagnostic purposes

An association between polymorphism of the heme oxygenase-1 and -2 genes and age-related macular degeneration

Iron may be implicated in the generation of oxidative stress by the catalyzing the Haber–Weiss or Fenton reaction. On the other hand, oxidative stress has been implicated in the pathogenesis of age-related macular degeneration (AMD) and heme oxygenase-1 (HO-1), encoded by the HMOX1 gene and heme oxygenase-2 (HO-2), encoded by the HMOX2 gene are important markers of iron-related oxidative stress and its consequences. Therefore, variability of the HMOX1 and HMOX2 genes might be implicated in the pathogenesis of AMD through the modulation of the cellular reaction to oxidative stress. In the present work, we investigated the association between AMD and a G → C transversion at the 19 position in the HMOX1 gene (the 19G>C-HMOX1 polymorphism, rs2071747) and a A → G transition at the −42 + 1444 position in the HMOX2 gene (the −42 + 1444A>G-HMOX2 polymorphism, rs2270363) and its modulation by some environmental factors. 279 patients with AMD and 105 controls were recruited in this study and the polymorphisms were typed by restriction fragment length polymorphism and allele-specific polymerase chain reaction (PCR). We observed an association between the occurrence of dry AMD and the G/A genotype of the −42 + 1444A>G-HMOX2 polymorphism (odds ratio (OR) 2.72), whereas the G/G genotype reduced the risk of dry AMD (OR 0.41). The G/C genotype and the C allele of the 19 G>C-HMOX1 polymorphism and the G/G genotype and the G allele of the −42 + 1444A>G-HMOX2 polymorphism were associated with progression of AMD from dry to wet form (OR 4.83, 5.20, 2.55, 1.69, respectively). On the other hand, the G/G genotype and the G allele of the 19 G>C-HMOX1 polymorphism and the A/G genotype and the A allele of the −42 + 1444A>G-HMOX2 polymorphism protected against AMD progression (OR 0.19, 0.19, 0.34, 0.59, respectively). Therefore, the 19G>C-HMOX1 and the −42 + 1444A>G-HMOX2 polymorphisms may be associated with the occurrence and progression of AMD

Genetic polymorphism of the iron-regulatory protein-1 and -2 genes in age-related macular degeneration

Iron can be involved in the pathogenesis of AMD through the oxidative stress because it may catalyze the Haber–Weiss and Fenton reactions converting hydrogen peroxide to free radicals, which can induce cellular damage. We hypothesized that genetic polymorphism in genes related to iron metabolism may predispose individuals to the development of AMD and therefore we checked for an association between the g.32373708 G>A polymorphism (rs867469) of the IRP1 gene and the g.49520870 G>A (rs17483548) polymorphism of the IRP2 gene and AMD risk as well as the modulation of this association by some environmental and life-style factors. Genotypes were determined in DNA from blood of 269 AMD patients and 116 controls by the allele-specific oligonucleotide-restriction fragment length polymorphism and the polymerase chain reaction-restriction fragment length polymorphism. An association between AMD, dry and wet forms of AMD and the G/G genotype of the g.32373708 G>A-IRP1 polymorphism was found (OR 3.40, 4.15, and 2.75). On the other hand, the G/A genotype reduced the risk of AMD as well as its dry or wet form (OR 0.23, 0.21, 0.26). Moreover, the G allele of the g.49520870 G>A-IRP2 polymorphism increased the risk of the dry form of the disease (OR 1.51) and the A/A genotype and the A allele decreased such risk (OR 0.43 and 0.66). Our data suggest that the g.32373708 G>A-IRP1 and g.49520870 G>A-IRP2 polymorphisms may be associated with increased risk for AMD

The role of Cat -262C/T, GPX1 Pro198Leu and Sod1+35A/C gene polymorphisms in a development of primary open-angle glaucoma in a Polish population

The development of glaucoma may be connected with a long-term exposure to oxidative stress caused by free radical (ROS). The main aim of this work was an analysis of associations of Cat-262C/T, GPX1 Pro198Leu and SOD1 35 A/C gene polymorphisms of antioxidant enzymes with a risk of open-angle glaucoma (POAG) in a Polish population. DNA samples collected from 209 patients with POAG and 191 healthy controls were used in this study. Polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). We found that the +35A/C polymorphisms of SOD1 were not associated with a risk of POAG. We found that C/T genotype (1-GPX1Pro198Leu, 2-Cat C262T) is associated with increased risk of open angle glaucoma (1-OR = 2.24; 95% CI: 1.46-3.44; p = 0.0001, 2-OR = 2.16; 95% CI: 1.35-3.34; p = 0.001). We also found that T/T genotype is a risk factor for progression of POAG (1-OR = 3.86; 95% Cl: 1.36-10.96; p = 0.007, 2-OR = 6.37; 95% CI: 1.39-29.28; p = 0.007). Finally our data suggest that gene polymorphisms of GPX1 Pro198Leu and CAT C262T may have a protective role in the development of primary open-angle glaucoma in a Polish population

Role of biochemical factors in the pathogenesis of keratoconus

Keratoconus (KC) is a corneal disease associated with structural abnormalities in the corneal epithelium, Bowman's layer and stroma and altered concentration of tear components. KC corneas show a different pattern of collagen lamellae than their normal counterparts. Also, a reduction of several collagen types in KC epithelium and stroma was observed. Altered expression and/or activity of lysyl oxidase, a critical enzyme of the biogenesis of connective tissue detected in KC corneas, may weaken covalent bonds between collagen and elastin fibrils, what may lead to biomechanical deterioration of the cornea. Increased activity of matrix metalloproteinases observed in KC may induce the degradation of the extracellular matrix causing damage to the cornea. Oxidative and nitrative stress play an important role in KC pathogenesis and KC corneas are characterized by the disturbed lipid peroxidation and nitric oxide pathways. Malfunctioning of these pathways may lead to accumulation of their toxic by-products inducing several detrimental effects, along with apoptosis of the corneal cells, which may result from the loss of β-actin or increased levels of cytokines, including interleukin-1 and -6. Change in the expression of genes associated with wound healing, including the nerve growth factor and the visual system homeobox 1, may contribute to increased susceptibility of KC corneas to injury. Consequently, biochemical changes may play an important role in KC pathophysiology and, therefore, can be considered in prevention, diagnosis, prognosis and in the therapy of this disease as well