Novel compound heterogeneous mutations in CYB5R3 gene leading to methemoglobinemia (type I) in a Chinese boy.

INTRODUCTION: Congenital methemoglobinemia (RCM) caused by CYB5R3 deficiency due to the mutations in the reduced nicotinamide adenine dinucleotide (NADH) cytochrome b5 reductase (CYB5R) gene is an autosomal recessive inherited disease. Clinically, it can be divided into two types, namely red blood cell affected type (RCM I) and systemically affected type (RCM II). CASE PRESENTATION: A 5-year-old male patient was diagnosed with cyanosis for 5 years. Physical examination showed cyanosis in areas such as lips, fingers, and toes. Laboratory examination revealed low pulse oxygen saturation (81%) and increased blood methemoglobin (23.6%). Gene testing revealed the compound heterozygous mutations in the CYB5R3 gene, c.149G>A (p.Arg50Gln) and c.331A>G (p.Lys111Glu), respectively originating from his parents. By constructing 3D models of CYB5R3 wild-type and mutant types using SWISS-MODEL software, it was found that the mutation caused significant structural abnormalities in the CYB5R protein. The relationship between CYB5R3 gene mutation sites, amino acid change, enzyme activity, and methemoglobinemia types I and II were listed and analyzed. CONCLUSION: A case of congenital RCM type I caused by compound heterozygous mutations in the CYB5R3 gene was reported, with c.331A>G (p.Lys111Glu) being the newly reported mutation. The homozygosity or heterozygosity of CYB5R3 gene mutations that lead to premature termination, loss of exons, and change in amino acid properties in FAD or NADH binding domains, is positively correlated with the severity (from type I to type II) of methemoglobinemia.

Complement components regulates ferroptosis in CVB3 viral myocarditis by interatction with TFRC.

BACKGROUND: Dysregulated cell death machinery and an excessive inflammatory response in Coxsackievirus B3(CVB3)-infected myocarditis are hallmarks of an abnormal host response. Complement C4 and C3 are considered the central components of the classical activation pathway and often participate in the response process in the early stages of virus infection. METHODS: In our study, we constructed a mouse model of CVB3-related viral myocarditis via intraperitoneal injection of Fer-1 and detected myocarditis and ferroptosis markers in the mouse myocardium. Then, we performed co-IP and protein mass spectrometry analyses to explore which components interact with the ferroptosis gene transferrin receptor (TFRC). Finally, functional experiments were conducted to verify the role of complement components in regulating ferroptosis in CVB3 infection. RESULTS: It showed that the ferroptosis inhibitor Fer-1 could alleviate the inflammation in viral myocarditis as well as ferroptosis. Mechanistically, during CVB3 infection, the key factor TFRC was activated and inhibited by Fer-1. Fer-1 effectively prevented the consumption of complement C3 and overload of the complement product C4b. Interestingly, we found that TFRC directly interacts with complement C4, leading to an increase in the product of C4b and a decrease in the downstream complement C3. Functional experiments have also confirmed that regulating the complement C4/C3 pathway can effectively rescue cell ferroptosis caused by CVB3 infection. CONCLUSIONS: In this study, we found that ferroptosis occurs through crosstalk with complement C4 in viral myocarditis through interaction with TFRC and that regulating the complement C4/C3 pathway may rescue ferroptosis in CVB3-infected cardiomyocytes.

Homocysteine in retinal artery occlusive disease: A meta-analysis of cohort studies.

Few studies have reported the relationship between retinal artery occlusion (RAO) and plasma homocysteine (Hcy) levels. Our goal was to evaluate the association between the plasma Hcy level and the risk of RAO disease. Several databases were searched for all published studies that involved Hcy and RAO. Six studies evaluated hyperhomocysteinemia (hHcy) in retinal artery occlusion patients and controls; the incidence of hHcy in patients with RAO was higher than the control and the pooled odds ratio (OR) was 6.64 (95% confidence interval (CI): 3.42, 12.89). Subgroup analyses showed that the ORs were 4.77 (95% CI: 2.69, 8.46) in Western countries, 22.19 (95% CI: 2.46, 200.37) in Asian countries, 9.70 (95% CI: 4.43, 21.20) in the age matched group, 11.41 (95% CI: 3.32, 39.18) in the sex matched group, 9.70 (95% CI: 4.37, 21.53) in the healthy control group, and 6.82 (95% CI: 4.19, 11.10) in the sample size >30. The mean plasma Hcy level from 5 case-control studies was higher than controls, and the weighted mean difference (WMD) was 6.54 (95% CI: 2.79, 10.29). Retinal artery occlusion is associated with elevated plasma Hcy levels. Our study results suggest that hHcy is probably an independent risk factor for RAO.

Dexamethasone distribution characteristic following controllable continuous sub-tenon drug delivery in rabbit.

Drug delivery systems are required to be safe, minimally invasive and effectively delivery drug to the target tissues. But delivery drugs to the eye has not yet satisfied this need. Here, we focused on examining the distribution of dexamethasone (DEX) in ocular and plasmic samples following controllable continuous sub-Tenon drug delivery (CCSDD) of dexamethasone disodium phosphate (DEXP) in rabbit, and to compare that with two traditional routes: subconjunctival injection and intravenous injection. The DEX concentration was analyzed by Shimadzu LC-MS 2010 system. In CCSDD group, during observed 24 h, the mean DEX level in collected samples from highest to lowest following in order: sclera, cornea, retina/choroid, iris, plasma, aqueous humor, lens and vitreous body. In ocular solid tissue, the DEX level in posterior segment is higher than in anatomic corresponding anterior segment, but it is opposite in ocular fluid tissue. High levels of DEX were maintained at 12 h in the ocular tissue immediately after the administration. Even at 24 h, the mean DEX concentration was 31.72 ng/ml and 22.40 ng/ml in aqueous and vitreous, respectively. In CCSDD group, the ocular DEX exposure (AUC0-24) is much higher and plasma exposure is much less than IV group, and it is also similar in SC group except iris. The amount of DEX levels are markedly increased in ocular tissues but it yield lower plasma levels indicating reduction of systemic absorption by CCSDD. Thus, CCSDD is an effective method of delivering DEX into anterior and posterior segment of the eye.

Preliminary study of a controllable device for subtenon drug infusion in a rabbit model.

BACKGROUND AND OBJECTIVE: Conventional methods to treat intraocular diseases are invasive or associated with adverse effects. A minimally invasive means of sustained-release drug delivery to the vitreous is required. This study evaluated a novel device for subtenon drug delivery to the vitreous, relative to a single subconjunctival injection. METHODS: Sixty adult New Zealand White rabbits were randomly assigned to receive demethylvancomycin (DMV) by continuous subtenon delivery with the flow rate of 0.1 ml/hr for 24 hr, or as a single 0.3 ml subconjunctival injection in the right eyes. Rabbits were killed in subgroups of six at 1, 3, 6, 12 and 24 hr. The DMV concentration of the vitreous humour of the right eye was analysed by high-performance liquid chromatography. RESULTS: Overall, the vitreous DMV concentration of the subtenon group was significantly higher than that of the subconjunctival group (F = 25.928, p = 0.001). The DMV concentration of the subtenon group was also significantly higher than that of the subconjunctival group at 3, 6, 12 and 24 hr (t = 2.457, 5.064, 3.085, 4.207; p = 0.04, 0.01, 0.018, 0.004, respectively). In the subtenon group, the DMV concentration reached maximum (2.41 ± 0.67 µg/ml) at 6 hr, and at 24 hr was 2.37 ± 1.23 µg/ml. In the subconjunctival group, the DMV concentration reached maximum (0.48 ± 0.27 µg/ml) at 1 hr and declined to 0.09 ± 0.05 µg/ml at 24 hr. CONCLUSION: Subtenon application with this novel minimally invasive design is an effective method for delivering an appropriate drug to the vitreous in a sustained and controllable amount.

Opacification of a Hydrophilic Acrylic Intraocular Lens.

Opacification of a hydrophilic acrylic intraocular (IOL) lens is a rare phenomenon. We herein report a case of a 57-year man complaining of decreased vision at left eye for the last 4 months. He had undergone phacoemulsification with IOL implantation 2 years back. IOL opacification was observed through slit-lamp. IOL exchange was carried out. The exchanged IOL and a new lens of the same model were sent to laboratory for pathologic analysis. Confocal microscopy showed uniformly distributed granules from the surface to 80 µm internal surface. Scanning electron microscopy (SEM) showed the details of granules. X-ray photoelectron spectroscopy (XPS) confirmed the presence of calcium and silicon in the deposits. Aqueous humor biochemical analysis revealed a normal result. We discuss the possible causes of opacification of IOL in this report.

Research on the comparison of the demethylvancomycin's diffusion-deposition characteristics in the ocular solid tissues of sustained subtenon drug delivery with subconjunctival injection.

PURPOSE: To compare the demethylvancomycin's diffusion-deposition characteristics in the ocular solid tissues of sustained subtenon drug delivery with subconjunctival injection. METHOD: Sixty adult white rabbits were randomly assigned to the subtenon drug delivery group and the subconjunctival injection group. The subtenon drug delivery group was continuously infused demethylvancomycin to the subtenon of rabbits. The subconjunctival injection group was injected demethylvancomycin to the subconjunctival of rabbits. Cornea, iris and sclera were collected for high-performance liquid chromatography analyses to determine drug concentrations at one hour, three hours, six hours, 12 h and 24 h of drug administration. WinNonlin 6.3 was used to calculate the parameters of cumulative area under the curve (AUCcum) of demethylvancomycin. RESULTS: The peak levels of demethylvancomycin concentration of the subtenon drug delivery group and the subconjunctival injection group were 92.406 ± 21.555 and 51.778 ± 14.001 µg/g in cornea, 28.451 ± 10.229 µg/g and 42.271 ± 27.291 µg/g in iris, 153.166 ± 51.738 µg/g and 57.423 ± 18.480 µg/g in sclera. The differences of concentrations between the two groups in cornea and sclera were statistically significant (F = 487.775, p < 0.001; F = 132.748, p < 0.001). The difference in iris was not statistically significant (F = 4.848, p = 0.064). The maximum of AUCcum of the subtenon drug delivery group and the subconjunctival injection group was 1808.23 h * µg/g and 273.73 h * µg/g in cornea, 489.12 h * µg/g and 216.16 h * µg/g in iris and 2166.34 h * µg/g and 392.57 h * µg/g in sclera at 24 h of drug administration. CONCLUSION: The sustained subtenon drug delivery had a better drug permeability and accumulation in the intraocular solid tissue compared to subconjunctival injection, which demonstrated it was probably a promising and effective approach for treating posterior segment diseases and endophthalmitis.

Controllable continuous sub-tenon drug delivery of dexamethasone disodium phosphate to ocular posterior segment in rabbit.

Corticosteroids have been used for treatment of posterior segment eye diseases, but the delivery of drug to the posterior segments is still a problem to resolve. In our study, we explore the feasibility of Sub-tenon's Controllable Continuous Drug Delivery to ocular posterior segment. Controllable continuous sub-tenon drug delivery (CCSDD) system, intravenous injections (IV) and sub-conjunctival injections (SC) were used to deliver dexamethasone disodium phosphate (DEXP) in rabbits, the dexamethasone concentration was measured in the ocular posterior segment tissue by Shimadzu LC-MS 2010 system at different time points in 24 h after first dose injection. Levels of dexamethasone were significantly higher at 12, 24 h in CCSDD than two other approaches, and at 3, 6 h in CCSDD than IV in vitreous body (p < 0.01); at 6, 12, 24 h in CCSDD than two other approaches, and at 1, 3 h in CCSDD than IV in retinal/choroidal compound (p < 0.01); at 3, 6, 12, 24 h in CCSDD than two other approaches, and at 1 h in CCSDD than IV in sclera (p < 0.05). The AUC0-24 in CCSDD group is higher than two other groups in all ocular posterior segment tissue. Our results demonstrated that dexamethasone concentration could be sustained moderately higher in the posterior segment by CCSDD than SC and IV, indicating that CCSDD might be a therapeutic alternative to treat a variety of intractable posterior segment diseases.

Clinical and genetic identification of a large chinese family with autosomal dominant retinitis pigmentosa.

BACKGROUND: Retinitis pigmentosa (RP) is a group of inherited retinal dystrophies characterized by night blindness, progressive peripheral visual field loss, and loss of central vision. Fifty-three RP pathogenic genes are responsible for RP. Pre-mRNA processing factor 31(PRPF31) gene is the third most common cause of autosomal dominant retinitis pigmentosa (adRP), and so far more than 40 mutations in PRPF31 have been detected. PURPOSE: To identify the underlying genetic defect in a five-generation Chinese family affected with adRP and to study the genotype-phenotype relationship of this family. METHODS: Detailed clinical investigations were undertaken and peripheral blood samples were collected from 25 individuals. Microsatellite (STR) markers tightly linked to genes known to be responsible for adRP were selected for linkage analysis. Exons and adjacent splice junctions of the candidate gene were amplified and sequenced. RESULTS: This adRP family exhibited an incomplete penetrance of the RP phenotype. In affected individuals, age of disease onset was from infancy to 4 years of age. Typical RP features were associated with this mutation. Linkage analysis identified a maximum two-point LOD score of 3.20 with D19S418, which is close to PRPF31. A mutation PRPF31: (c.358-359 del AA) was identified by linkage analysis. CONCLUSIONS: A PRPF31 mutation was identified to be responsible for adRP in a large Chinese family. Our findings expand the mutation spectrum of RP in the Chinese population.

Effect of advanced glycation end products on the expression of hypoxia-inducible factor-1α and vascular endothelial growth factor proteins in RF/6A cells.

The aim of this study was to investigate the effect of advanced glycation end products (AGEs) on the expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) proteins in RF/6A cells cultured in vitro, and to investigate the association between the expression of HIF-1α and VEGF proteins. RF/6A cells were cultured in vitro and treated with AGEs and non-glycated albumin control at various concentrations (0, 50, 100, 200, 400 and 800 mg/l) for 24 h. The expression of the VEGF protein was detected by ELISA, and western blot analysis was used to determine the levels of HIF-1α protein. The expression of HIF-1α and VEGF proteins was significantly higher in the AGE group compared with the non-glycated control group (all P<0.05). With the increase in concentration of AGEs, the expression levels of HIF-1α and VEGF protein increased and reached a maximum at 200 mg/l AGE, then decreased at 400 and 800 mg/l. However this effect was not observed in the non-glycated control groups. There was a positive correlation between the expression of HIF-1α and VEGF (P<0.05). AGEs induced the expression of HIF-1α and VEGF proteins in RF/6A cells in a concentration-dependent manner. AGEs may upregulate the expression of VEGF protein by increasing the levels of HIF-1α protein, demonstrating the potential role of HIF-1α-targeted therapy in neovascularization.