Targeted Gene Candidates for Treatment and Early Diagnosis of Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is an eye disease that impairs the sharp and central vision need for daily activities. Recent advances in molecular biology research not only lead to a better understanding of the genetics and pathophysiology of AMD but also to the development of applications based on targeted gene expressions to treat the disease. Clarification of molecular pathways that causing to development and progression in dry and wet types of AMD needs comprehensive and comparative investigations in particular precious biopsies involving peripheral blood samples from the patients. Therefore, in this investigation, dry and wet types of AMD patients and healthy individuals were aimed at investigating in regard to targeted gene candidates by using gene expression analysis for the first time. 13 most potent candidate genes involved in neurodegeneration were selected via in silico approach and investigated through gene expression analysis to suggest new targets for disease therapy. For the analyses, 30 individuals (10 dry and 10 wet types AMD patients and 10 healthy people) were involved in the study. SYBR-Green based Real-Time PCR analysis was performed on isolated peripheral blood mononuclear cells (PBMCs) to analyze differentially expressed genes related to these cases. According to the investigations, only the CRP gene was found to be upregulated for both dry and wet disease types. When the downregulated genes were analyzed, it was found that 11 genes were commonly decreased for both dry and wet types in the aspect of expression pattern. From these genes, CFH, CX3CR1, FLT1, and TIMP3 were found to have the most downregulated gene expression properties for both diseases. From these results, it might be concluded that these common upregulated and downregulated genes could be used as targets for early diagnosis and treatment for AMD.

Blood thiamine pyrophosphate concentration and its correlation with the stage of diabetic retinopathy.

PURPOSE: To assess the possible relationship between blood thiamine pyrophosphate (TPP) concentration and stage of diabetic retinopathy (DR). METHODS: This comparative cross-sectional study included 80 patients with type 2 diabetes mellitus (T2DM) and 20 age- and gender-matched healthy controls. Diabetic patients were subclassified into four groups each consisting of 20 subjects: no DR, mild-moderate non-proliferative DR (mild-moderate NPDR), severe NPDR, and proliferative DR (PDR). Blood TPP concentration was assessed with high-performance liquid chromatography (HPLC) assay and was correlated with the stage of DR. RESULTS: Mean blood TPP concentration was 80.2 ± 14.8 nmol/L in control group. It was, respectively, 69.85 ± 18.1, 64.95 ± 13.4, 61.9 ± 13.4 and 60.75 ± 14.3 nmol/L in no DR, mild-moderate NPDR, severe NPDR and PDR groups. For mild-moderate NPDR, severe NPDR and PDR groups, TPP concentrations were significantly lower compared with controls (p: 0.014, 0.002, 0.001, respectively). Mean TPP concentration for NPDR patients was higher than for PDR patients, but the difference was not significant (p: 0.478). ANOVA revealed a significant difference between TPP concentrations of groups (p: 0.001). Mean TPP concentration decreased with the stage of DR, and number of patients with thiamine deficiency increased gradually with the stage of DR. A negative correlation was found between the TPP level and occurrence of DR (p: 0.000). CONCLUSION: The results suggest that lower blood TPP concentrations were associated with higher risk of DR. Thiamine might play an important role in the pathophysiology and progression of DR. Thiamine and its derivatives might represent an approach to the prevention and/or treatment of early DR.

Carvacrol Protects Against Paclitaxel-Induced Retinal and Optic Nerve Cytotoxicity: A Histopathological Study.

OBJECTIVES: Carvacrol (CV) is a phenolic monoterpenoid found in the essential oil of a number of aromatic plants and herbs. The present study was an investigation of the potential protective effect of CV against paclitaxel (PTX)-induced retinal and optic nerve cytotoxicity in rats. METHODS: A total of 18 adult male Wistar albino rats (250-400g) were randomized into 3 equal groups comprising 6 animals each. Group 1 (control group) received intraperitoneal (IP) saline solution (0.5 mL/200 g) weekly for 4 weeks. Group 2 received an IP dose of PTX (5 mg/kg), and Group 3 received CV (25 mg/kg) 30 minutes after an IP dose of PTX (5 mg/kg) weekly for 4 weeks. At the conclusion of the experimental period, the retinal and optic nerve tissues of the subjects were evaluated histopathologically. RESULTS: All of the retinal specimens in Group 1 (control) were histopathologically normal. In Group 2 (PTX), all of the eyes (6/6) revealed increased retinal vascularity and rosette-like structures in the outer nuclear layer, and in Group 3 (PTX-CV), all of the eyes (6/6) demonstrated normal retinal vascularity and the absence of rosette-like structures. All of the optic nerve specimens in Group 1 (control) were histopathologically normal. In Group 2 (PTX), all of the eyes (6/6) demonstrated severe vacuolization and a decreased number of astrocytes and oligodendrocytes in the optic nerve specimens, while 3 eyes (3/6) showed marked single cell necrosis. None of the eyes in Group 3 (PTX-CV) demonstrated either vacuolization or a reduction in the number of astrocytes and oligodendrocytes. No remarkable single cell necrosis was observed in the optic nerve specimens of Group 3 (PTX-CV). CONCLUSION: The histopathological findings indicated that CV played a protective role against PTX-induced cytotoxicity. CV might be a promising resource to counteract oxidative stress-based cytotoxicity in the field of retinal and optic nerve disorders.

Carvone protects against paclitaxel-induced retinal and optic nerve cytotoxicity: a histopathological study.

Purpose: Carvone (CVN) is a natural monoterpene found in essential oils of many aromatic plant species. In this study, we investigated the protective effect of CVN against paclitaxel (PTX)-induced retinal and optic nerve cytotoxicity in rats. Methods: Twenty-four male adult Wistar albino rats (250-400 g) were randomized into four equal groups comprising six animals in each. Group 1 (control group) received intraperitoneal (i.p.) saline solution (0.5 mL/200 g) weekly for 4 weeks. Group 2 received i.p. CVN [(S)-(+)- CVN, (5S)-5-Isopropenyl-2-methyl-2-cyclohexen-1-one, C10H14, 25 mg/kg], while Group 3 received i.p. PTX (5 mg/kg) weekly for 4 weeks. Group 4 received i.p. CVN (25 mg/kg) 30 min after i.p. PTX (5 mg/kg) weekly for 4 weeks. At the end of the experimental period, retinal and optic nerve tissues were evaluated histopathologically. Results: All retinal specimens in control and CVN groups were histopathologically normal. In PTX group all eyes (6/6) demonstrated increased retinal vascularity and rosette-like structures in the outer nuclear layer, while in PTX-CVN group all eyes (6/6) demonstrated normal retinal vascularity and absence of rosette-like structures. All optic nerve specimens in control and CVN groups were histopathologically normal. In PTX group all eyes (6/6) demonstrated severe vacuolization and decrease in the number of astrocytes and oligodendrocytes, while 3 eyes (3/6) demonstrated marked single cell necrosis. In PTX-CVN group, 4 eyes (4/6) demonstrated moderate vacuolization while, 2 eyes (2/6) had none. Compared with PTX group, 1 eye (1/6) in PTX-CVN group demonstrated a decrease in numbers of astrocytes and oligodendrocytes while 5 eyes (5/6) were normal. No remarkable single cell necrosis was observed in PTX-CVN group. Conclusions: Our histopathological findings demonstrated the potential protective role of CVN against PTX-induced retinal and optic nerve cytotoxicity. CVN might be a promising molecule in counteracting oxidative stress-based cytotoxicity in the field of retinal and optic nerve disorders.

Nitrite, neopterin levels and tryptophan degradation in allergic conjunctivitis.

PURPOSE: The study aims to evaluate changes in neopterin levels and tryptophan degradation which are induced by Th1-type immune response and nitric oxide metabolism which may be involved in allergic inflammation. METHODS: Serum nitrite, kynurenine, tryptophan and neopterin levels were evaluated in 36 patients with seasonal allergic conjunctivitis, along with these values in 41 healthy subjects. All these parameters have been compared with symptom and sign scores. RESULTS: Tryptophan and kynurenine concentrations were not significantly changed, while serum nitrite concentrations were significantly low, and neopterin levels were significantly increased in patients compared to healthy subjects (p < 0.05). There was a significant relationship between symptom scores and serum nitrite levels in patients. CONCLUSIONS: This preliminary study demonstrates that serum nitric oxide metabolism might have a role in allergic conjunctivitis. Serum neopterin levels but not tryptophan metabolism could serve as a biomarker in patients with seasonal allergic conjunctivitis.

The Protective Effect of Thiamine Pryophosphate Against Sugar-Induced Retinal Neovascularisation in Rats.

The aim of this study was to investigate the effect of thiamine pyrophosphate (TPP), administered via sugar water, on retinal neovascularisation in rats. Animals were assigned to three groups, namely the TPP sugar-water group (TPSWG, n = 12), the control group (CG, n = 12) and the healthy group (HG, n = 12). The TPSWG was injected intraperitoneally with TPP once a day for 6 months. CG and HG rats were given distilled water in the same way. TPSWG and CG rats were left free to access an additional 0.292 mmol /ml of sugar water for 6 months. The fasting blood glucose (FBG) levels of the animals were measured monthly. After 6 months, biochemical, gene expression and histopathologic analyses were carried out in the retinal tissues removed from the animals after they were killed. The measured FBG levels were 6.96 ± 0.09 mmol/ml (p < 0.0001 vs. HG), 6.95 ± 0.06 mmol/ml (p < 0.0001 vs. HG) and 3.94 ± 0.10 mmol/ml in the CG, TPSWG and HG groups, respectively. The malondialdehyde (MDA) levels were found to be 2.82 ± 0.23 (p < 0.0001 vs. HG), 1.40 ± 0.32 (p < 0.0001 vs. HG) and 1.66 ± 0.17 in the CG, TPSWG and HG, respectively. Interleukin 1 beta (IL-1ß) gene expression was increased (3.78 ± 0.29, p < 0.0001) and total glutathione (tGSH) was decreased (1.32 ± 0.25, p < 0.0001) in the retinal tissue of CG compared with TPSWG (1.92 ± 0.29 and 3.18 ± 0.46, respectively). Increased vascularisation and oedema were observed in the retinal tissue of CG, while the retinal tissues of TPSWG and HG rats had a normal histopathological appearance. A carbohydrate-rich diet may lead to pathological changes in the retina even in nondiabetics, but this may be overcome by TPP administration.

Infantile Nephropathic Cystinosis: A Novel CTNS Mutation.

Cystinosis is a rare autosomal recessive metabolic disorder characterized by the accumulation of cystine in lysosomes, which results from defects in the carrier-mediated transport protein encoded by the CTNS gene. Infantile nephropathic cystinosis (INC) is one of the major complications of cystinosis. It is characterized by findings of Fanconi's syndrome within the first year of life. Here we report two patients with INC presenting with signs of Fanconi's syndrome and describe a novel CTNS mutation.

Gene expression and histopathological evaluation of thiamine pyrophosphate on optic neuropathy induced with ethambutol in rats.

AIM: To compare the effects of thiamine pyrophosphate (TPP) and thiamine (TM) in oxidative optic neuropathy in rats induced by ethambutol. METHODS: The animals were divided into four groups: a control group (CG), an ethambutol control (ETC) group, TM plus ethambutol group (TMG), and TPP plus ethambutol group (TPPG). One hour after intraperitoneal administration of TM 20 mg/kg to the TMG group and TPP 20 mg/kg to TPPG group, 30 mg/kg ethambutol was given via gavage to all the groups but the CG. This procedure was repeated once daily for 90d. After that period, all rats were exposed to high levels of anaesthesia in order to investigate the gene expression of malondialdehyde and glutathione in removed optic nerve tissue and histopathologically to examine these tissues. RESULTS: Malondialdehyde gene expression significantly increased, whereas glutathione gene expression significantly decreased in the ETC group compared to the CG. TM could not prevent the increase of malondialdehyde gene expression and the decrease of glutathione, while TPP significantly could suppress. Histopathologically, significant vacuolization in the optic nerve, single-cell necrosis in the glial cells, and a decrease in oligodendrocytes were observed in the ETC group. Vacuolization in the optic nerve, a decrease in oligodendrocytes and single-cell necrosis were found in the TMG group, while no pathological finding was observed in the TPPG group except for mild vacuolization. CONCLUSION: TPP protects the optic nerve against the ethambutol-induced toxicity but TM does not. TPP can be beneficial in prophilaxis of optic neuropathy in ethambutol therapy.

Effect of thiamine pyrophosphate on retinopathy induced by hyperglycemia in rats: A biochemical and pathological evaluation.

PURPOSE: Information is lacking on the protective effects of thiamine pyrophosphate (TPP) against hyperglycemia-induced retinopathy in rats. This study investigated the biochemical and histopathological aspects of the effect of TPP on hyperglycemia-induced retinopathy induced by alloxan in rats. MATERIALS AND METHODS: The rats were separated into a diabetic TPP-administered group (DTPG), a diabetes control group (DCG) and a healthy group (HG). While the DTPG was given TPP, the DCG and HG were administered distilled water as a solvent at the same concentrations. This procedure was repeated daily for 3 months. At the end of this period, all of the rats were euthanized under thiopental sodium anesthesia, and biochemical and histopathological analyses of the ocular retinal tissues were performed. The results of the DTPG were compared with those of the DCG and HG. RESULTS: TPP prevented hyperglycemia by increasing the amount of malondialdehyde and decreasing endogen antioxidants, including total glutathione, glutathione reductase, glutathione S-transferase and superoxide dismutase. In addition, the amounts of the DNA oxidation product 8-hydroxyguanine were significantly lower in the retinas of the DTPG compared to the DCG. In the retinas of the DCG, there was a marked increase in vascular structures and congestion, in addition to edema. In contrast, little vascularization and edema were observed in the DTPG, and there was no congestion. The results suggest that TPP significantly reduced the degree of hyperglycemia-induced retinopathy. CONCLUSIONS: The results of this study indicate that TPP may be useful for prophylaxis against diabetic retinopathy.

The effect of thiamine pyrophosphate on ethambutol-induced ocular toxicity.

CONTEXT: Ethambutol-induced retinal oxidative damage in patients with tuberculosis is still not being adequately treated. The protective effect of thiamine pyrophosphate against oxidative damage in some tissues has been reported, but no information on the protective effects of thiamine pyrophosphate against ethambutol-induced oxidative retinal damage has been found in the medical literature. OBJECTIVE: The objective is to investigate whether thiamine pyrophosphate has a protective effect against oxidative retinal damage in rats induced by ethambutol. MATERIALS AND METHODS: Experimental animals divided into four groups (n = 10): the healthy group (HG), the ethambutol control group (EMB), thiamine + ethambutol group (Thi-EMB) and thiamine pyrophosphate + ethambutol group (TPP-EMB). The rats in the TPP-EMB and Thi-EMB groups were administered thiamine pyrophosphate and thiamine, respectively, at doses of 20 mg/kg intraperitoneally. Distilled water was administered intraperitoneally to the HG and the EMB groups as a solvent in the same volumes. One hour after drug injection, 30 mg/kg ethambutol was administered via an oral gavage to the TPP-EMB, Thi-EMB and EMB groups. This procedure was repeated once a day for 90 days. At the end of this period, all rats were euthanized under high-dose thiopental sodium anesthesia, and biochemical and histopathological investigations of the retinal tissue were performed. RESULTS: Malondialdehyde (MDA) and DNA damage product 8-hydroxyguanine levels were significantly lower in the retinal tissue of TPP-EMB and HG groups compared to those of the Thi-EMB and EMB groups, and total glutathione (tGSH) was also found to be higher. In addition, severe retinal tissue vascularization, edema and loss of ganglion cells were observed in the Thi-EMB and EMB groups, whereas histopathological findings for the TPP-EMB group were observed to be close to normal. DISCUSSION AND CONCLUSION: These findings suggest that thiamine pyrophosphate protects retinal tissues from ethambutol-induced oxidative damage, and thiamine does not. This positive effect of thiamine pyrophosphate may be useful in the prevention of ocular toxicity that occurs during ethambutol use.

The ocular surface side effects of an anti-psychotic drug, clozapine.

PURPOSE: The purpose of this study is to investigate the effects of long-term clozapine usage on tear film stability and corneal topographic parameters. MATERIAL AND METHODS: The study was conducted between March 2014 and November 2014. Thirty patients who were diagnosed of schizophrenia and have been under clozapine treatment for 2.73 ± 0.73 years (range 2-4 years) were involved in this study (group 1). Thirty healthy subjects (group 2) who have statistically similar demographic features compared with the group 1, were involved as a control group. Full ophthalmologic examination with biomicroscopy and indirect ophthalmoscopy was applied. Corneal topographic parameters were measured using the Pentacam HR and Schirmer test was done. Statistical analysis of the subjects was evaluated by using SPSS (for Windows version 16.0; SPSS Inc., Chicago, IL) program. RESULTS: K1 value was measured as 43.39 ± 0.17 D (43-43.50 D) and K2 value was measured as 43.39 ± 0.06 D (43.30-43.50 D) in groups 1 and 2, respectively. In groups 1 and 2, K2 values were noted as 43.86 ± 0.27 D (43.50-44.50 D) and 43.72 ± 0.18 D (43.50-44.00 D), respectively. Central corneal thickness was found to be 523.93 ± 15.66 µm (495-554 µm) and 550.13 ± 1.03 µm (520-580 µm) in groups 1 and 2, respectively. Corneal apex thickness was 525.86 ± 15.75 µm (497-556 µm) in group 1 and 551.60 ± 14.99 µm (521-581 µm) in group 2. The corneal thickness of thinnest location was 520.93 ± 15.60 µm (492-551 µm) and 548.06 ± 15.17 µm (518-578 µm) in groups 1 and 2, respectively. Corneal volume was determined as 58.13 ± 3.46 mm(3) (52-64 mm(3)) in group 1 and 60.73 ± 3.76 mm(3) (54-66 mm(3)) in group 2. The Schirmer test showed thickness of 3.33 ± 0.72 mm (2-4 mm) and 13.60 ± 1.59 mm (11-16 mm) in groups 1 and 2, respectively. The mean fluorescein break-up time was 5.40 ± 1.50 s (3-8 s) and 12.46 ± 1.40 s (10-14 s) in groups 1 and 2, respectively. There was a statistically significant difference in the Schirmer test, fluorescein break-up time, central corneal thickness, corneal apex, and the thinnest corneal location thickness between the two groups. CONCLUSION: Clozapine may induce dry eye syndrome and thus may lead to morphological alterations in corneal parameters through its anticholinergic and antidopaminergic activities. Because of these corneal alterations, one should be aware of evaluating patients having diseases like glaucoma or preoperative selection of corneal refractive surgery candidates.

Thickness alterations of retinal nerve fiber layer in children with sleep-disordered breathing due to adenotonsillar hypertrophy.

OBJECTIVE: This study is designed to assess whether hypoxia which is caused by apnea and hypopnea episodes, has an effect on retinal nerve fiber layer (RNFL) thickness, using optical coherence tomography (OCT) in pediatric patients with Adenotonsillar hypertrophy (ATH). METHODS: Fifty-seven children patient with AHT, and 31 healthy non-AHT children (between 6 and 12 ages) were enrolled in this study. Obstructive symptoms of the patients with ATH were assessed by using OSA-18 survey. The patients were divided into 2 groups as mild (>60 and <80) and severe (>80) OSAS patients, according to OSA-18 survey total scores. RNFL thickness, in the four quadrants (superior, nasal, inferior and temporal) patient's both eyes, was measured by optical coherence tomography. RNFL parameters of control and patient groups were compared. Correlation between OSA survey scores and RNFL thickness of the patient groups were examined. RESULTS: A positive correlation was found between ages and RNLF thickness of all subjects enrolled in this study (r=+0.107, p<0.05). And also a poor correlation was found between OSA-18 survey scores and RNFL parameters in patient group (between -0.031 and +0.016 at right and left eyes, p>0.05). No statistically significant alteration in RNFL thickness was found between the patient and control groups (p>0.05). CONCLUSION: Age range (6-12) of the patients with ATH in our study considers that possible OSAS time was not long enough to affect RNLF thickness. Remembering the risk of optic injury development in children with ATH (in a long term), tonsillectomy and/or adenoidectomy operations shouldn't be delayed.

Peripapillary Retinal Nerve Fibre Layer Thinning Secondary to Nutritional Folic Acid Deficiency.

Folic acid has a fundamental role in central nervous system (CNS) function at all ages, especially the methionine synthase-mediated conversion of homocysteine to methionine, which is essential for nucleotide synthesis and genomic and non-genomic methylation. Folic acid and vitamin B12 may have roles in the prevention of disorders of CNS development, mood disorders, and dementias, including Alzheimer disease and vascular dementia in elderly people. The authors examined the peripapillary retinal nerve fibre layer thickness (RNFLT) in patients with nutritional folic acid deficiency using optical coherence tomography (OCT). Patients were divided into two groups according to blood folic acid levels: blood folic acid <7 nmol/L as Group 1 and >7 nmol/L as Group 2. Peripapillary RNFL measurements were performed. There were significant positive correlations between serum folate levels and RNFLT in all quadrants (p < 0.05), except for the temportal quadrant (p = 0.41).

Decreased serum paraoxonase 1 activity and increased serum homocysteine and malondialdehyde levels in age-related macular degeneration.

Age-related macular degeneration (AMD) is one of the most common causes of vision loss. AMD has been classified into two forms: atrophic and exudative forms. The exudative form is associated with choroidal neovascularization of the subretinal macular region, resulting in a sudden loss of central vision. However, the exact cause of AMD remains unknown. Several risk factors have been postulated, including smoking, atherosclerosis, and low levels of antioxidant enzymes. Malondialdehyde (MDA), a lipid peroxidation product, is used as a marker of oxidative stress. Paraoxonase 1 (PON1) metabolizes lipid peroxides and prevents oxidation of low-density lipoprotein. Increased levels of homocysteine may cause vascular endothelial injury by releasing free radicals. The purpose of this study is to investigate the relationships between serum PON1 activity and the serum levels of homocysteine and MDA in AMD. Forty patients with exudative-type AMD (63.3 +/- 5 years) and 40 controls (61+/- 4 years) were assessed in a cross-sectional study. The serum PON1 activity was significantly lower in the patients with AMD than that in the controls (p < 0.001). In contrast, the serum levels of MDA and homocysteine were significantly higher in the patients than those in the controls (p < 0.001, for both). In AMD patients, significant negative correlation was found between PON1 activity and MDA level (r = -0.493, p < 0.05) and between PON1 activity and homocysteine level (r = -0.557, p < 0.05). Increased serum homocysteine and MDA levels may be responsible for the decreased PON1 activity in patients with AMD.

The effect of L-carnitine treatment on levels of malondialdehyde and glutathione in patients with age related macular degeneration.

OBJECTIVE: The aim of this study was to determine the antioxidant properties of the L-carnitine (LC) in the treatment of patients with age-related macular degeneration (AMD). MATERIALS AND METHODS: This study involved 60 patients diagnosed with early AMD. The patients were divided into two groups. Group I was the study group that received LC supplementation for 3 months. Group II was the control group and did not consent to LC supplementation over the 3 months. At the end of the 3-month period, markers of lipid peroxidation, malondialdehyde (MDA) and reduced glutathione (GSH) were measured in the two groups. RESULTS: In the study group, the MDA level was significantly reduced, while the GSH level was significantly increased at the end of the 3-month period (P<0.001). CONCLUSION: Our results suggest that LC may protect against oxidative damage by decreasing the MDA level, a marker of lipid peroxidation, and increasing GSH.