SLC4A11 mutations causative of congenital hereditary endothelial dystrophy (CHED) progressing to Harboyan syndrome in consanguineous Pakistani families.

BACKGROUND: Autosomal recessive corneal hereditary endothelial dystrophy (CHED) is a rare congenital disorder of cornea. Mutations in SLC4A11 gene are associated with CHED phenotype. CHED is also an early feature of Harboyan syndrome. The aim of the present study was to identify genetic mutations in the SLC4A11 gene in CHED cases belonging to inbred Pakistani families. Furthermore, all homozygous mutation carriers were investigated for hearing deficit. METHODS AND RESULTS: This study included consanguineous CHED families presented at Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan from June 2018 to September 2018. DNA was extracted from blood samples. Direct sequencing of SLC4A11 gene was performed. All identified variants were evaluated by in silico programs i.e., SIFT, PolyPhen-2, and MutationTaster. Pathogenicity of the two identified splice site variants was analyzed by Human Splicing Finder and MaxEnt Scan. Screening of five CHED families revealed a total of three previously un reported (p.Arg128Gly, c.2241-2A > T and c.1898-2A > C in family CHED19, CHED22 and CHED26 respectively) and two already reported homozygous disease causing variants (p.Arg869Cys and p.Val824Met in family CHED24 and CHED25 respectively) as predicted by mutation taster. All of these variants segregated with disease phenotype and were not detected in controls. CONCLUSION: Affected individuals of the five CHED families screened in this study had the disease due to SLC4A11 mutations and progressing to Harboyan syndrome. Identification of previously unreported mutations aid to heterogeneity of SLC4A11 and CHED pathogenesis as well as helped to provide genetic counseling to affected families.

Topical Ocular Anesthetic Use among Welders of Rawalpindi City, Pakistan.

A descriptive cross-sectional survey was done from January to June 2018 in welding shops of Rawalpindi city, Pakistan. The objectives of the study were to determine the frequency of topical ocular anesthetic use among welders and to assess the knowledge and practices of welders regarding safety measures. One hundred and fifty-eight welders from age group of 20 years and above, having welding work experience of more than one year, were included in the study. The sampling strategy was non-random convenient sampling. A pretested structured questionnaire was used to collect data. Topical ocular anesthetic use among welders was found to be 45.6%. Statistically significant association was found between knowledge and practices of welders regarding their safety measures (p<0.05). On binary logistic regression, work experience was found to be the strongest predictor of good knowledge (OR = 4.15, 95% CI = 1.45 - 12.15) and practices (OR=10.46 95% CI = 2.92 - 37.51). Key Words: Welder, Topical anesthetic abuse, Knowledge, Practices, Perceptions.

Utility of teleconsultation in accessing eye care in a developing country during COVID-19 pandemic.

OBJECTIVE: To evaluate the utility of teleconsultation in the provision of eye care services during the COVID-19 lockdown. Disparities in the consultation burden of sub-specialities and socio-demographic differences in teleconsultation utilization were also assessed. METHODS: Al-Shifa Trust Eye Hospital Rawalpindi began audio and video teleconsultation using broadband telecommunication services during the lockdown. Patients' and consultations' data gathered during the first three weeks after the commencement of this programme were compared with data from the four weeks prior to lockdown. The weekly consultation ratio and overall consultation burden of sub-specialities were measured. Chi-Square tests of association determined the relationship between different variables (socioeconomic status and consultation characteristics) and consultation modality (on-site vs online). RESULTS: In total, 17507 on-site consultations (4377/week) were conducted compared to 1431 teleconsultations (477/week), which maintained 10.89% of the weekly pre-lockdown eye care services. The post-lockdown teleconsultation programme saw a relatively higher percentage of service utility among female (47.09% vs 44.71%), younger-age (31.33±19.45 vs 41.25±23.32 years) and higher-socioeconomic-status (32.21% vs 0.30%) patients compared to pre-lockdown on-site consultations. The most common indication for teleconsultation was red-eye (16.70%). While cornea and glaucoma clinics maintained most of the pre-lockdown services (30.42% and 29% respectively), the highest dropout was seen in optometric and vitreoretinal services supporting only 5.54% and 8.28% of pre-lockdown services, respectively. CONCLUSION: Digital initiatives could partially maintain eye care services during the lockdown. Focused strategies to improve teleconsultation utilization are required during the pandemic and beyond.

Nanomaterials-based solid phase extraction and solid phase microextraction for heavy metals food toxicity.

In the last few years, nanomaterials are widely used sorbents for the extraction of heavy metals in food samples. The nanomaterials have a larger surface area and show high selectivity, fast adsorption capability, and high efficiency for food contaminants (heavy metals). Carbon nanomaterials (CNMs), magnetic nanoparticles (MNPs), nano-imprinted polymers (NIPs), nano-based metal-organic frameworks (N-MOFs), and silica nanoparticles (SiNPs) are most prominent nanomaterials used in the preconcentration and determination of heavy metals. The most popular sorbent-based techniques for the extraction of heavy metals are solid phase extraction (SPE) and solid phase microextraction (SPME). The use of these nanomaterial sorbents increases the extraction efficiency of both techniques. This review summarizes the nanomaterial sorbents (published 2015 to May-2020) used in solid phase extraction (SPE) and solid phase microextraction (SPME) for heavy metals extraction in food.

Hollow fiber-based liquid phase microextraction followed by analytical instrumental techniques for quantitative analysis of heavy metal ions and pharmaceuticals.

Hollow-fiber liquid-phase microextraction (HF-LPME) and electromembrane extraction (EME) are miniaturized extraction techniques, and have been coupled with various analytical instruments for trace analysis of heavy metals, drugs and other organic compounds, in recent years. HF-LPME and EME provide high selectivity, efficient sample cleanup and enrichment, and reduce the consumption of organic solvents to a few micro-liters per sample. HF-LPME and EME are compatible with different analytical instruments for chromatography, electrophoresis, atomic spectroscopy, mass spectrometry, and electrochemical detection. HF-LPME and EME have gained significant popularity during the recent years. This review focuses on hollow fiber based techniques (especially HF-LPME and EME) of heavy metals and pharmaceuticals (published 2017 to May 2019), and their combinations with atomic spectroscopy, UV-VIS spectrophotometry, high performance liquid chromatography, gas chromatography, capillary electrophoresis, and voltammetry.

Comparison of Changes in Central Corneal Thickness During Corneal Collagen Cross-Linking, Using Isotonic Riboflavin Solutions With and Without Dextran, in the Treatment of Progressive Keratoconus.

PURPOSE: To compare intraoperative changes in central corneal thickness (CCT) during corneal cross-linking, using 2 different isotonic riboflavin solutions either with dextran or with hydroxy propyl methylcellulose, in the treatment of progressive keratoconus. METHODS: In this retrospective study, we analyzed records of corneal thickness measurements, taken during various steps of cross-linking. Cross-linking was performed using either isotonic riboflavin with dextran (group A) or isotonic riboflavin with hydroxy propyl methylcellulose (without dextran) (group B). CCT measurements were recorded before and after epithelial removal, after saturation with respective isotonic riboflavin solution, after use of hypotonic riboflavin in selected cases, and after ultraviolet A (UV-A) application. A mixed-way analysis of variance was conducted on CCT readings within each group and between both groups, and p < 0.05 was considered significant. RESULTS: In group A (100 cases), after saturation with isotonic riboflavin, CCT was decreased by a mean of 51.4 µm (12.1%). In 64%, CCT was <400 µm and additional hypotonic riboflavin was used. After UV-A irradiation, CCT was decreased by a mean of 46.7 µm (11.4%). In group B (100 cases), after saturation with isotonic riboflavin, CCT was increased by a mean of 109.4 µm (26.1%). After UV-A exposure, CCT was increased by a mean of 59.2 µm (11.2%). There was a substantial main effect for time on CCT during corneal cross-linking (CXL), p < 0.001, within both groups. The main effect comparing CCT readings between groups A and B was also significant, p < 0.001. CONCLUSIONS: During cross-linking, isotonic riboflavin with dextran causes a significant decrease in corneal thickness, whereas dextran-free isotonic riboflavin causes a significant increase in corneal thickness, thus facilitating the procedure.

TNF-α Genetic Predisposition and Higher Expression of Inflammatory Pathway Components in Keratoconus.

Purpose: To date keratoconus (KC) pathogenesis is undefined; however, the involvement of inflammatory pathways in disease development is becoming apparent. In the present study, we investigated the role of a promoter region polymorphism rs1800629 (-308G>A) in the inflammatory pathway component TNF-α and its effects on the expression of TNF-α and downstream molecules tumor necrosis factor receptor 1 and 2 (TNFR1 and TNFR2), v-rel avian reticuloendotheliosis viral oncogene homolog A (RELA), and interleukin 6 (IL-6) in KC development. Methods: TNF-α promoter polymorphism rs1800629 (-308G>A), was genotyped in 257 sporadic KC patients and 253 healthy controls. Enzyme-linked immunosorbent assay (ELISA) was performed to assess for the -308G>A genotypes. Quantitative polymerase chain reaction (qPCR) was carried out to compare the mRNA expression of TNF-α, TNFR1, TNFR2, RELA, and IL6 in the corneal tissues of 20 KC patients and 20 donor controls. Results: The -308G>A genotype GA was found to be significantly associated with KC development (dominant model [odds ratio (OR) = 6.67 (95% confidence interval [CI] = 4.28-10.42), P < 0.001]) and allele-A (OR = 4.30, 95%CI = 2.93-6.34, P < 0.001). TNF-α serum levels were significantly raised in patients with GA genotype (196.5 ± 69.5 pg/mL) compared to reference genotype GG (21.7 ± 8.2 pg/mL) (P < 0.0001). There was a significant overexpression of TNF-α (P = 0.002), TNFR2 (P = 0.0001), RELA (P = 0.0117), and IL6 (P = 0.0007) in the KC corneal tissues as compared to the control. Conclusions: The GA genotype of the TNF-α -308G>A polymorphism is a significant genetic risk factor for the pathogenesis of KC. Moreover, this single nucleotide polymorphism (SNP) was observed to be associated with deregulated expression of downstream molecules, thus further reinforcing the role of the inflammatory pathway components in the development of KC.

Variants in the ASB10 Gene Are Associated with Primary Open Angle Glaucoma.

BACKGROUND: Recently nonsynonymous coding variants in the ankyrin repeats and suppressor of cytokine signaling box-containing protein 10 (ASB10) gene were found to be associated with primary open angle glaucoma (POAG) in cohorts from Oregon and Germany, but this finding was not confirmed in an independent cohort from Iowa. The aim of the current study was to assess the role of ASB10 gene variants in Pakistani glaucoma patients. METHODS: Sanger sequencing of the coding exons and splice junctions of the ASB10 gene was performed in 30 probands of multiplex POAG families, 208 sporadic POAG patients and 151 healthy controls from Pakistan. Genotypic associations of individual variants with POAG were analyzed with the Fisher's exact or Chi-square test. RESULTS: In total 24 variants were identified in POAG probands and sporadic patients, including 11 novel variants and 13 known variants. 13 of the variants were nonsynonymous, 6 were synonymous, and 5 were intronic. Three nonsynonymous variants (p.Arg49Cys, p.Arg237Gly, p.Arg453Cys) identified in the probands were not segregating in the respective families. This is not surprising since glaucoma is a multifactorial disease, and multiple factors are likely to be involved in the disease manifestation in these families. However a nonsynonymous variant, p.Arg453Cys (rs3800791), was found in 6 sporadic POAG patients but not in controls, suggesting that it infers increased risk for the disease. In addition, one synonymous variant was found to be associated with sporadic POAG: p.Ala290Ala and the association of the variant with POAG remained significant after correction for multiple testing (uncorrected p-value 0.002, corrected p-value 0.047). The cumulative burden of rare, nonsynonymous variants was significantly higher in sporadic POAG patients compared to control individuals (p-value 0.000006). CONCLUSIONS: Variants in ASB10 were found to be significantly associated with sporadic POAG in the Pakistani population. This supports previous findings that sequence variants in the ASB10 gene may act as a risk factor for glaucoma.

Corneal collagen cross-linking for keratoconus: results of 3-year follow-up in Pakistani population.

OBJECTIVE: To assess the effectiveness and safety of corneal collagen cross-linking with riboflavin and ultraviolet A (UV-A) light in arresting the progression of keratoconus. DESIGN: Prospective, nonrandomized experimental study. PARTICIPANTS: Seventy-one eyes of 66 patients with progressive keratoconus. METHODS: Corneal cross-linking was carried out with riboflavin and UV-A light in patients with progressive keratoconus at Al-Shifa Trust Eye Hospital, Pakistan. Standard protocol of cross-linking comprising epithelial debridement, instillation of isotonic riboflavin (0.1%) for 30 minutes, followed by application of UV-A light for 30 minutes with riboflavin was followed. Variables of interest were uncorrected and best corrected visual acuity (BCVA) with spectacles, spherical equivalent refraction, maximum keratometric reading, and central corneal thickness. Three-year results of these variables after cross-linking were analyzed. RESULTS: Mean age of patients was 19.79 ± 3.71 years; 75.8% were male and 24.2% were female. After 3 years, uncorrected visual acuity improved in 31.0% by mean 2.0 ± 1.06 Snellen lines, remained same in 64.8%, and deteriorated in 4.2% by mean 1.33 ± 0.57 lines. BCVA improved in 56.3% by mean 2.37 ± 1.10 Snellen lines, remained the same in 40.8%, and deteriorated in 2.8% by mean 1.50 ± 0.70 lines. Spherical equivalent refraction decreased in 33.8% by mean 2.29 ± 1.48 D, remained stable in 60.6%, and increased in 5.6% by mean 1.43 ± 0.42 D. Maximum keratometric reading showed mean regression of 2.64 ± 1.42 D in 60.6%, stabilization in 35.2%, and mean progression of 2.0 ± 0.17 D in 4.2%. In 95.8% of cases, progression of keratoconus halted. Central corneal thickness was decreased by mean 10.32 ± 21.19 µm. CONCLUSIONS: Cross-linking is an effective and safe treatment option in halting the progression of keratoconus.

Association of known common genetic variants with primary open angle, primary angle closure, and pseudoexfoliation glaucoma in Pakistani cohorts.

PURPOSE: Despite the different etiology of primary open angle glaucoma (POAG), primary angle closure glaucoma (PACG), and pseudoexfoliative glaucoma (PEXG), several studies have suggested that these forms of glaucoma have overlapping genetic risk factors. Therefore, the aim of this study was to evaluate the role of genetic variants recently associated with POAG in different types of glaucoma in Pakistani POAG, PACG, and PEXG patient cohorts. METHODS: Six variants in CDKN2B-AS1 (rs4977756), CDKN2B (rs1063192), ATOH7 (rs1900004), CAV1 (rs4236601), TMCO1 (rs4656461), and SIX1 (rs10483727) were genotyped using TaqMan assays. A total of 513 unrelated patients with glaucoma (268 with POAG, 125 with PACG, and 120 with PEXG) and 233 healthy controls were included in the study. Genotypic and allelic associations were analyzed with a chi-square test. RESULTS: The frequency of the G allele of TMCO1 rs4656461 was significantly lower in the patients with POAG (p=0.003; OR [odds ratio]=0.57), PACG (p=0.009; OR=0.52), and PEXG (p=0.01; OR=0.54) compared to the control individuals. The T allele of ATOH7 rs1900004 was observed less frequently in the patients with PACG (p=0.03; OR=0.69) compared to the control individuals. The A allele of CAV1 rs4236601 was found more frequently in the patients with POAG (p=0.008; OR=1.49) compared to the control individuals. This study demonstrates that the TMCO1 rs4656461 variant is associated with POAG, PACG and PEXG in the Pakistani population. Our study was unable to confirm previous associations reported for variants in CDKN2B-AS1, CDKN2B, and SIX1 with any type of glaucoma. CONCLUSIONS: In conclusion, we found consistent evidence of the significant association of three common variants in TMCO1, ATOH7, and CAV1.

Assessment of serum lipids in patients with age related macular degeneration from Pakistan.

OBJECTIVE: To determine serum lipids in patients with age related macular degeneration from Pakistani population. METHODS: The study was a cross sectional, randomized and case-control. Selected subjects ages were > or = 50 years and were normotensive, non-diabetic with no family history of any such disease and no complication of posterior ocular chamber other than age related macular degeneration (AMD). Controls were age matched healthy individuals with no symptoms of AMD. Diagnosis of AMD was done through conventional diagnostic techniques by professional ophthalmologists. Serum samples were analyzed for total cholesterol, triglycerides, LDL and HDL using commercially available kits. Data were compared with Student's t-test. Pearson correlation was calculated for relationship between different parameters. P < 0.05 was considered significant. RESULTS: Compared to controls, AMD patients had significantly greater total cholesterol concentration (p < 0.041), and power HDL/LDL ratio (p < 0.038), while serum triglycerides, HDL and LDL were non-significantly different from control subjects. Total cholesterol in AMD patients was significantly correlated with TG, LDL and HDL (p < 0.0001). CONCLUSION: The study indicates that high cholesterol might be a predictor of AMD and can be a diagnostic parameter.

Polymorphisms in matrix metalloproteinases MMP1 and MMP9 are associated with primary open-angle and angle closure glaucoma in a Pakistani population.

PURPOSE: Matrix metalloproteinases (MMPs) play an important role in remodeling of the extracellular matrix during development and growth of various tissues including the eye. Various functional polymorphisms in MMPs have been implicated in the pathogenesis of different types of glaucoma. The aim of the present study was to investigate the role of various polymorphisms in Pakistani patients with glaucoma. METHODS: The present case-control study included 112 patients with primary open-angle glaucoma (POAG), 82 patients with primary angle closure glaucoma (PACG), and 118 control subjects. Genotyping of polymorphisms was done using PCR followed by restriction fragment length polymorphism analysis. RESULTS: A significant difference in the genotype frequencies of MMP1 rs1799750 (-1607 1G/2G) was observed between the patients with POAG and the control subjects (p = 0.001). This was attributed to the female subjects (p < 0.001), while the association was not significant in male subjects (p > 0.47). In addition, a significant difference was observed in genotype frequencies of MMP9 rs17576 (c.836A>G) in patients with PACG compared to the control subjects (p < 0.001), which after gender stratification remained significant in men (p = 0.009) but not in women (p = 0.14). No significant associations were found for MMP7 (c.-181T>C) and MMP9 (c.-1562C>T) polymorphisms. CONCLUSIONS: Our data suggest that the MMP1 rs1799750 (-1607 1G/2G) and MMP9 rs17576 polymorphisms might be of value for further study as potential gender-dependent risk factors for developing POAG and PACG, respectively, in Pakistan.

MTHFR gene C677T and A1298C polymorphisms and homocysteine levels in primary open angle and primary closed angle glaucoma.

PURPOSE: To investigate the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C genotypes and plasma concentrations of total homocysteine (tHcy) in Pakistani patients with primary open angle glaucoma (POAG) and primary closed angle glaucoma (PCAG). METHODS: This was a prospective case-control study. A total of 295 patients (173 POAG, 122 PCAG) and 143 age- and sex-matched controls were subdivided into two ethnic groups, Punjabis (Punjab province, central Pakistan) and Pathans (North-West Frontier Province, northern Pakistan). Genotypes of the MTHFR C677T and A1298C polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). An enzyme-linked immunosorbent assay was used to determine the total serum homocysteine (tHcy) levels. Associations were determined by logistic regression analysis. RESULTS: Frequency distributions of genotypes and combined genotypes as well as homocysteine levels were obtained. The overall distribution of the C677T genotype was found to be significantly associated with PCAG (CC 69%, CT 21%, TT 10%; p=0.001, chi(2)=12.6), but not with POAG (CC 71%, CT 28%, TT 1%; p=0.98, chi(2)=0.02) as compared to the controls (CC 71%, CT 29%, TT 1%). The Pathan cohorts revealed no association with the disease; however, the Punjabis demonstrated a significant association with PCAG (CC 75%, CT 11%, TT 13%; p<0.001, chi(2)=17.2). PCAG in the Punjabi subjects was also significantly associated with the A1298C polymorphism (AA 43%, AC 54%, CC 3%; p<0.001, chi(2)=33.9) as compared to the controls. Combined genotype data showed no association with POAG; however, a significant association with all combined genotypes was observed in the overall PCAG subjects (p<0.05, chi(2)=20.1). This difference was particularly apparent in the TTAA and TTAC combinations that were completely absent in the control groups (p<0.05. chi(2)=49.6). Mean serum tHcy levels were found to be significantly increased in the POAG (15.2+/-1.28 micromol/l, p<0.001) and PCAG (20.8+/-4.8 micromol/l) groups as compared to the controls (10.0+/-0.97 micromol/l). The tHcy levels in the TT and AC genotype were significantly elevated in the PCAG group (67+/-12.39 micromol/l, p<0.001; 23+/-5.94 micromol/l, p=0.027) as compared to the controls. CONCLUSION: The TT and AC genotypes of MTHFR C677T and A1298C polymorphisms and the combined genotype TTAC were associated with PCAG in Punjabi subjects of Pakistani origin and correlated with the high serum tHcy levels seen in these patients.

Enhanced binding of circulating SLE autoantibodies to catecholestrogen-copper-modified DNA.

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease characterized by circulating and tissue fixed autoantibodies reactive with self-antigens, including nucleic acid and other nuclear components. The pathways by which these autoantibodies act as a pathogenic factor remain elusive. Present study has investigated the role of estrogens in SLE etiopathogenesis. Estrogen-modified DNA [4-OHE(2)-Cu(II)-DNA] showed single- and double-strand breaks, hyperchromicity, decrease in Tm, and modification of bases. The 4-OHE(2)-Cu(II)-DNA exhibited increased binding with naturally occurring anti-DNA autoantibodies as compared to the unmodified native form (P < 0.001) as assessed by ELISA, quantitative precipitin titration, and gel retardation assay. The relative affinity of anti-DNA antibodies for modified and native DNA was in the order of 2.1 x 10(-7) M and 1.3 x 10(-6) M, respectively. The data suggested that DNA modified with 4-OHE(2) and Cu(II) may be one of the factors for the induction of circulating anti-DNA autoantibodies in SLE.

C677T polymorphism in the methylenetetrahydrofolate reductase gene is associated with primary closed angle glaucoma.

PURPOSE: To determine whether or not there is an association of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism with disease in cohorts of primary open-angle glaucoma (POAG) and primary closed-angle glaucoma (PCAG) from Pakistan. METHODS: This was a prospective study consisting of 150 patients (90 POAG and 60 PCAG) and 70 control subjects. Genomic DNA was extracted from leukocytes of the peripheral blood. MTHFR C677T polymorphism analysis was performed by the polymerase chain reaction-restriction fragment length polymorphism (RFLP) technique. RESULTS: The prevalence of the MTHFR C/T genotype was 22.2% in POAG, 13.3% in PACG, and 18.6% in controls whereas the MTHFR T/T genotype was present solely in the PACG group (6.9%). The difference regarding the T/T genotype between PACG and controls was statistically significant (p<0.01). CONCLUSIONS: The MTHFR C677T polymorphism was found to be associated with PCAG but not POAG in patients of Pakistani origin.