Further studies are needed to elucidate the causes of this phenomenon
Further studies are needed to elucidate the causes of this phenomenon. all the groups, but no statistically significant differences were evident between the HMC NC23 and ARC NC23 Groups. Likewise, CRYAA mRNA and protein levels in the HMC NC56 Group were significantly lower than the ARC NC56 Group and high-myopic controls. == Conclusions == High myopia is a risk factor for dark nucleus. Downregulation ofCRYAAvia the hypermethylation of CpG islands in its promoter could underlie the earlier onset of dark nucleus in high-myopic patients. == Introduction == High myopia, defined as myopia exceeding 6.00 diopters or axis length 26 mm, is a disorder that affects almost the entire human eye, from the anterior pole to the posterior pole. High myopia can be associated with high refractive errors, cataract, open-angled glaucoma, and retinopathy, all of which are recognized as significant problems of subspecialties related to ophthalmology[1], and more IRAK-1-4 Inhibitor I difficulties are encountered during surgery in such cases. As the incidence of high myopia is much higher in Asia than elsewhere[2], it is likely that high-myopic cataract (HMC) is more common in Asia[3]. Several population-based studies[3][6]have examined the association between high myopia and cataract. For example, data from the Blue Mountains Eye Study[4]suggested that high myopia is associated with both nuclear and posterior subcapsular cataract. In another series of studies[2],[7], it was reported that nuclear cataract is strongly associated with high-axial myopia. Praveenet al.[7]also reported that cataract density is higher in patients with high myopia than in other groups of patients. However, high myopia is not associated with posterior subcapsular or cortical cataract. We have noticed that some patients with high myopia develop dark nuclear cataract at an earlier age than high-myopic patients without a dark nucleus or patients with age-related cataract (ARC). Rabbit Polyclonal to BTC Patients with high-myopic dark nuclear cataract show rapid cataract progression at a relatively young age, they usually have a brown or dark nucleus, and may have a longer axis. As the largest cataract surgery center in Eastern China, we perform cataract surgery on more than 2,000 patients with high myopia each year, and those with high-myopic dark nuclear cataract are referred to our center much earlier than other patients because of a rapid deterioration in their vision. However, cataract surgery is very hazardous in such patients because of the high risk of posterior capsule tear, vitreous prolapse[8], persistent postoperative corneal edema, and retinal detachment. Therefore, it is particularly important to determine the etiology of this disorder. Alpha-crystallin, composed of two subunits, A- and B-crystallin, is the most abundant structural protein in the human lens[9],[10]. The biologic role of -crystallin is to bind to lens proteins that denature over time, thereby maintaining long-term lens transparency. This is particularly important in the lens, as there is no protein turnover in the inner part[11][13]and, once synthesized, these proteins persist for an individuals lifespan. Therefore, adequate expression of -crystallin is vital for maintaining the transparency of the human lens. However, as we recently reported[14], A-crystallin expression is significantly decreased in ARC compared with healthy controls as a result of hypermethylation of CpG islands in the promoter ofCRYAA, the gene encoding A-crystallin. IRAK-1-4 Inhibitor I Recent studies[15][17]have focused on the epigenetic regulation of gene expression, which alters DNAtranscription factor affinity through two mechanisms: DNA methylation and histone modification. In DNA methylation, addition of a methyl group to cytosine in DNA changes the electrostatic nature of chromatin. Hypermethylation of CpG islands in a promoter causes heterochromatin formation and gene silencing[16]. Very IRAK-1-4 Inhibitor I few studies have addressed the reasons why patients with high myopia show earlier-onset and higher-density cataract. We hypothesized that hypermethylation of CpG islands in theCRYAApromoter underlies the etiology of HMC as.