Regional analysis of diabetic retinopathy and co-existing social and demographic factors in the overall population of Poland

INTRODUCTION

The aim of our study was to analyse the regional differences in diabetic retinopathy (DR) prevalence and its co-existing social and demographic factors in the overall population of Poland in the year 2017.

MATERIAL AND METHODS

Data from all levels of healthcare services at public and private institutions recorded in the National Health Fund database were evaluated. International Classification of Diseases codes were used to identify patients with type 1 and type 2 diabetes mellitus (DM) and with DR. Moran's I statistics and Spatial Autoregressive (SAR) model allowed us to understand the distribution of DR prevalence and its possible association with environmental and demographic exposures.

RESULTS

In total, 310,815 individuals with diabetic retinopathy (DR) were diagnosed in the year 2017 in Poland. Of them, 174,384 (56.11%) were women, 221,144 (71.15%) lived in urban areas, and 40,231 (12.94%) and 270,584 (87.06%) had type 1 and type 2 DM, respectively. The analysis of the SAR model showed that the significant factors for the occurrence of DR in particular counties were a higher level of average income and a higher number of ophthalmologic consultations per 10,000 adults.

CONCLUSIONS

The analyses of social, demographic, and systemic factors co-existing with DR revealed that level of income and access to ophthalmologic and diabetic services are crucial in DR prevalence in Poland.

High expression of Matrix Gla Protein in Schnyder corneal dystrophy patients points to an active role of vitamin K in corneal health

PURPOSE

Schnyder corneal dystrophy (SCD) is a rare autosomal dominant disorder characterized by corneal lipid accumulation and caused by UBIAD1 pathogenic variants. UBIAD1 encodes a vitamin K (VK) biosynthetic enzyme. To assess the corneal and vascular VK status in SCD patients, we focused on matrix Gla protein (MGP), a VK-dependent protein.

METHODS

Conformation-specific immunostainings of different MGP maturation forms were performed on corneal sections and primary keratocytes from corneal buttons of two SCD patients with UBIAD1 p.Asp112Asn and p.Asn102Ser pathogenic variants and unrelated donors. Native or UBIAD1-transfected keratocytes were used for gene expression analysis. Plasma samples from SCD patients (n = 12) and control individuals (n = 117) were subjected for inactive desphospho-uncarboxylated MGP level measurements with an ELISA assay.

RESULTS

Substantial amounts of MGP were identified in human cornea and most of it in its fully matured and active form. The level of mature MGP did not differ between SCD and control corneas. In primary keratocytes from SCD patients, a highly increased MGP expression and presence of immature MGP forms were detected. Significantly elevated plasma concentration of inactive MGP was found in SCD patients.

CONCLUSION

High amount of MGP and the predominance of mature MGP forms in human cornea indicate that VK metabolism is active in the visual system. Availability of MGP seems of vital importance for a healthy cornea and may be related to protection against corneal calcification. Systemic MGP findings reveal a poor vascular VK status in SCD patients and indicate that SCD may lead to cardiovascular consequences.

First nation-wide study of diabetic retinopathy in Poland in the years 2013-2017

AIMS

To assess the prevalence and time trends of diabetic retinopathy (DR) in the overall population of Poland from 2013 to 2017 and diagnose the risk factors of occurring DR among patients with diabetes mellitus (DM).

METHODS

Data from all levels of healthcare services at public and private institutions recorded in the National Health Fund (NHF) database were evaluated. International Classification of Diseases codes (ICD-9 and ICD-10) and unique NHF codes were used to identify DM type 1 and type 2 patients, DR and treatment procedures including laser photocoagulation, pars plana vitrectomy (PPV), anti-VEGF and steroid intravitreal injections.

RESULTS

The overall registered prevalence of DR in the entire population of Poland was 0.81%. The mean prevalence of DR was 20.01% in the population with type 1 DM and 9.70% in the population with type 2 DM. In the study period, women represented 56.36% of all individuals registered with DR and 55.09% of all DM patients. In Poland, only 6.34% of all DM patients with DR received specific treatment with laser photocoagulation of the retina (82.32%), PPV (11.56%), anti-VEGF or steroid injections (5.15% and 0.97%, respectively). Cox regression hazard analysis showed that the risk of DR was associated with DM treatment only by GPs, female sex, coexisting systemic diseases and urban residence in both type 1 and type 2 DM.

CONCLUSIONS

A 5-year retrospective analysis reveals the mean prevalence of DR in the population with type 1 and type 2 DM in Poland was rather low.

Multiple Differentially Methylated Regions Specific to Keratoconus Explain Known Keratoconus Linkage Loci

Purpose

Keratoconus (KTCN) is a complex eye disorder resulting in loss of visual function. Its development is affected by genetic and environmental components. The aim of this study was to unravel the role of epigenetic factors in KTCN.

Methods

To verify if DNA methylation may play a role in KTCN development, reduced representation bisulfite sequencing of five KTCN and five non-KTCN human corneas was performed.

Results

Multiple KTCN-specific differentially methylated regions were detected and many of them overlap previously identified KTCN linkage loci (3p14.3, 5q35.2, 13q32.3, 15q24.1, and 20p13) and chromosome arms that have been linked to KTCN (2q, 4q, 5p, 9p, 14q, and 17q). Reanalysis of the previously described RNA sequencing dataset of 25 KTCN and 25 non-KTCN human corneas revealed that 12 genes downregulated in KTCN and 6 upregulated genes overlapped or were located in the near vicinity of the identified differentially methylated regions. Particularly interesting were the DNA methylation changes in WNT3 and WNT5A encoding Wnt ligands, as they provide a potential explanation for the Wnt signaling pathway dysregulation observed in KTCN.

Conclusions

We presented the results of data analysis from the first study of DNA methylation changes in human KTCN corneas compared to non-KTCN samples. We were able to identify genomic regions with distinct patterns of DNA hypo- and hypermethylation and link them to previously found KTCN susceptibility loci as well as transcriptomic disruption of Wnt signaling pathway observed in KTCN.

Clinical diversity in patients with Schnyder corneal dystrophy-a novel and known UBIAD1 pathogenic variants

PURPOSE

Schnyder corneal dystrophy (SCD) is a rare inherited disease that leads to gradual vision loss by the deposition of lipids in the corneal stroma. The aim of this study is to report a novel pathogenic variant in the UBIAD1 gene and present clinical and molecular findings in Polish patients with SCD.

METHODS

Individuals (n = 37) originating from four Polish SCD families were subjected for a complete ophthalmological check-up and genetic testing. Corneal changes were visualized by slit-lamp examination, anterior segment optical coherent tomography (AS-OCT), and in vivo confocal microscopy (IVCM).

RESULTS

In a proband with primarily mild SCD that progressed rapidly at the end of the fifth decade of life, a novel missense pathogenic variant in UBIAD1 (p.Thr120Arg) was identified. The other studied SCD family represents the second family reported worldwide with the UBIAD1 p.Asp112Asn variant. SCD in the remaining two families resulted from a frequently identified p.Asn102Ser pathogenic variant. All affected subjects presented a crystalline form of SCD. The severity of corneal changes was age-dependent, and their morphology and localization are described in detail.

CONCLUSION

The novel p.Thr120Arg is the fourth SCD-causing variant lying within the FARM motif of the UBIAD1 protein, which underlines a high importance of this motif for SCD pathogenesis. The current study provides independent evidence for the pathogenic potential of UBIAD1 p.Asp112Asn and new information useful for clinicians.

DNA damage and repair in Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD) is a slowly progressive eye disease leading to blindness, mostly affecting people above 40 years old. The only known method of curing FECD is corneal transplantation. The disease is characterized by the presence of extracellular deposits called "cornea guttata", apoptosis of corneal endothelial cells, dysfunction of Descement's membrane and corneal edema. Oxidative stress is suggested to play a role in FECD pathogenesis. Reactive oxygen species produced during the stress may damage biomolecules, including DNA. In the present study we evaluated the extent of endogenous DNA damage, including oxidatively modified DNA bases, and damage induced by hydrogen peroxide as well as the kinetics of DNA repair in peripheral blood mononuclear cells of 50 patients with FECD and 43 age-matched controls without visual disturbances. To quantify DNA damage and repair we used the alkaline comet assay technique with the enzymes recognizing oxidative DNA damage, hOGG1 and EndoIII. We did not observe differences in the extent of endogenous and hydrogen peroxide-induced DNA damage between FECD patients and controls. However, we found a lower efficacy of DNA repair in FECD patients as compared with control individuals. The results obtained suggest that the lowering of the DNA repair capacity may be one of the mechanisms underlying the role of oxidative stress in the FECD pathology.

Demodex infections in general Polish population, in patients suffering from blepharitis, and among people who work with microscopes

In this study we examined 264 people to estimate the prevalence of Demodex infection. The subjects were divided into 4 groups. First two groups consisted of young people (mean age 22 years) and seniors (mean age 66 years) respectively. The third group included people who work with microscopes (mean age 44 years). Forth group consisted of patients with diagnosed blepharitis (mean age 65 years). From every individual 3-4 lashes were epilated from the eyelids of both eyes and examined under the microscope for Demodex mites. The statistical analysis based on logistic regression was used to estimate the probability of infection. Age was independent variable significant for this model (p < 0.001). Significant relation between age and probability of Demodex infection was showed. The lowest number of infected individuals was observed in the group of young subjects (only 5%), the highest in the blepharitis patients (74% infected). Among microscope users 30% were infected, in the group of seniors 34% were infected.

Genetics of Meesmann corneal dystrophy: a novel mutation in the keratin 3 gene in an asymptomatic family suggests genotype-phenotype correlation

PURPOSE

Juvenile epithelial corneal dystrophy of Meesmann (MCD, OMIM 122100) is a dominantly inherited disorder characterized by fragility of the anterior corneal epithelium and intraepithelial microcyst formation. Although the disease is generally mild and affected individuals are often asymptomatic, some suffer from recurrent erosions leading to lacrimation, photophobia, and deterioration in visual acuity. MCD is caused by mutations in keratin 3 (KRT3) or keratin 12 (KRT12) genes, which encode cornea-specific cytoskeletal proteins. Seventeen mutations in KRT12 and two in KRT3 have been described so far. The purpose of this study was to investigate the genetic background of MCD in a Polish family.

METHODS

We report on a three-generation family with MCD. Epithelial lesions characteristic for MCD were visualized with slit-lamp examination and confirmed by in vivo confocal microscopy. Using genomic DNA as a template, all coding regions of KRT3 and KRT12 were amplified and sequenced. Presence of the mutation was verified with restriction endonuclease digestion.

RESULTS

In the proband, direct sequencing of the polymerase chain reaction (PCR) product from amplified coding regions of KRT3 and KRT12 revealed a novel 1493A>T heterozygous missense mutation in exon 7 of KRT3, which predicts the substitution of glutamic acid for valine at codon 498 (E498V). Using PCR-Restriction Fragment Length Polymorphism (RFLP) analysis, the mutation was demonstrated to segregate with the disease (four affected members, three non-affected) and to be absent in 100 controls from the Polish population, indicating that it is not a common polymorphism.

CONCLUSIONS

Location of the E498V mutation emphasizes the functional relevance of the highly conserved boundary motifs at the COOH-terminus of the alpha-helical rod domain in keratin 3 (K3).

In vivo confocal microscopy of corneal grafts shortly after penetrating keratoplasty

PURPOSE

To describe the microstructural status of corneal grafts shortly after penetrating keratoplasty (PK) and to evaluate the efficacy and safety of confocal microscopy in examining corneal grafts at that time.

METHODS

A confocal microscope with a 40 x front lens was used to examine corneal grafts in 32 patients (32 eyes) 4 days after PK. Images were analyzed, and endothelial cell density counts were compared with presurgical, eye bank values determined by specular microscopy.

RESULTS

Microstructural alterations of the graft included epithelial and stromal edema, epithelial degeneration in both superficial and basal cell layers, dark stromal striae, activated keratocytes, and needle-like structures in the stroma. Descemet membrane folds were visible in 31 of 32 grafts; in 1 graft, the dense stromal edema did not allow imaging of posterior layers. Stromal nerve fibers were imaged in 28 grafts (88%). Endothelial cell density ranged from 1666 to 2548 cells/mm2 (mean+/-SD, 2125+/-283 cells/mm2); perioperative endothelial cell density loss varied from 0% to 29% (mean, 12%). No adverse reactions or signs of worsening of clinical condition were observed after the examination.

CONCLUSIONS

White light scanning slit confocal microscopy permits imaging of a graft's microstructure (including epithelium and stromal layers), as well as calculation of endothelium cell density, as soon as 4 days after PK. The most frequently observed morphologic alterations of corneal grafts shortly after PK include epithelial and stromal edema, epithelial degeneration, stromal striae, and Descemet membrane folds. Stromal nerves can still be seen in the graft 4 days after PK.

[Posterior polymorphous dystrophy--changes in corneal morphology in confocal microscopy]

PURPOSE

To describe the in vivo conocal microscopic findings in posterior polymorphous dystrophy (PPD).

MATERIAL AND METHODS

Eleven patients (22 eyes) with PPD suspected or clinically diagnosed were examined using scanning slit white light confocal microscopy (ConfoScan 3, Nidek Technologies).

RESULTS

Endothelial cell densities ranged from 716 to 2380 cells/mm2 and endothelial polymegathism was noted in all cases. In 5 cases PPD changes was reported unilateral. Confocal microscopy demonstrated a variety of vesicular and linear abnormalities. In 13 eyes exhibited bright, nucleus-like structures within endothelial cells. Stromal edema was noted in 4 cases.

CONCLUSIONS

To our knowledge, we present the largest case series of PPD imaged by in vivo confocal microscopy. Confocal microscopy images of PPD are very characteristic. This method allows to confirm presumptive or to identify final diagnosis. Our study enhances the value of confocal microscopy in detection and monitoring corneal abnormalities.