Effectiveness of carbonic anhydrase inhibitor loaded nanoparticles in the treatment of diabetic retinopathy

Diabetic Retinopathy (DRP) is a disease consisting of all the structural and functional changes that develop in the retinal layer of the eye due to diabetes. DRP is the most important cause of blindness between the ages of 20-74 in the world, and the most successful standard treatment option in the treatment of DRP is intravitreal injections. To synthesize acetazolamide loaded nanoparticles to be applied intravitreal treatment of DRP and to examine thein vitroefficacy of the nanoparticles. ACZ loaded PHBV nanoparticles (PHBV-ACZ NPs) formulations were prepared. Nanoparticles with a particle size of 253.20 ± 0.55 nm. A DRP model was established and characterized in HRMEC cells. The effect of the nanoparticles on permeability has been investigated and carrier proteins in BRB due to the development of DRP has been investigated. To establish thein vitroDRP model, HRMEC was stimulated with Recombinant human 165 Vascular Endothelial Growth Factor (VEGF), thereby temporarily reducing the expression levels of endothelial junction proteins, increasing the number of intercellular spaces in the monolayers of HRMECs. It was determined that after the cells were exposed to Carbonic anhydrase inhibitors (CAI) loaded nanoparticles, permeability decreased and protein expression increased.

Ocular pharmacokinetics and toxicity of nanoparticular acetazolamide: In vivo distribution and safety of PHBV-ACZ nanoparticle

Diabetic macular edema (DME) is defined as fluid accumulation in the macular region, between the retinal layers, due to many diseases, especially diabetes. DME is one of the major complications of diabetic retinopathy (DRP). Carbonic anhydrase inhibitors (CAI) are a pharmaceutical agent used in different fields, especially glaucoma treatment. Acetazolamide (ACZ), which is a CAI, is an active substance that has been used off-label for many years in the treatment of macular edema due to diabetes and many other diseases. The low solubility and bioavailability of ACZ limit its use in the treatment of DME. In this study, a nanoparticulate formulation was developed that would increase the solubility and bioavailability of ACZ and allow it to be administered intravitreally. ACZ was loaded on poly(3-hydroxybutyrate-co-3-Hydroxyvalerate) (PHBV) nanoparticles and the loading efficiency was 71.58 ± 1.22%. Toxicity of nanoparticles after intravitreal application was evaluated with anterior segment and posterior segment examination findings, intraocular pressure (IOP) measurements and electrophysiological tests. At the end of the 3-month follow-up, electroretinography (ERG) measurements demonstrated that ACZ loaded PHBV (PHBV-ACZ) nanoparticles did not cause loss of function in retinal cells. On histological examination, rare degenerative changes were observed in several cell groups. In addition, pharmacokinetic studies were performed to determine the tissue distribution of ACZ at various periods. ACZ was identified in vitreous humor and retina at the highest concentration. Based on our results, the prepared nanoparticle formulation can release long-term CAI for DRP therapy and accordingly can reduce the need for monthly intravitreal injections.

Tamoxifen related chorioretinal structural changes

PURPOSE

To evaluate the vascular structure of the choroid and each retinal layer in patients with breast cancer on tamoxifen therapy and compare them with healthy subjects.

MATERIALS AND METHODS

124 eyes of 62 patients with breast cancer who were on tamoxifen therapy (group 1) and 80 eyes of 40 healthy controls (group 2) were included in this prospective cohort study. The structure of the choroid was evaluated using enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) and choroidal binarisation. Spectral-domain OCT (SD-OCT) was performed to analyse the peripapillary nerve fibre layer thickness (pRNFL) and each retinal layer thickness. A subgroup analysis was performed based on chemotherapy history in Group 1. All parameters were compared between Group 1 and the healthy controls and between the subgroups of Group 1.

RESULTS

The subfoveal choroidal thickness and temporal and nasal directions were increased in Group 1 when compared with Group 2 (p < 0.05, each comparison). Choroidal vascularity index was significantly decreased in Group 1 compared with Group 2 (63.15 ± 3.11% and 65.37 ± 4.63%, p < 0.001). There were no significant differences in each retinal layer, pRNFL thickness, and choroid structural parameters between the subgroups of Group 1.

CONCLUSIONS

Increased choroidal thickness may be the initial finding of subclinical tamoxifen-induced retinopathy. Patients with breast cancer undergoing tamoxifen therapy may be screened prior to tamoxifen therapy and followed during treatment by SD-OCT.

The relation between serum inflammatory marker levels and serous retinal detachment in macular edema secondary to retinal vein occlusion Serum inflammatory marker levels in serous retinal detachment secondary to retinal vein occlusion

PURPOSE

To assess blood-derived inflammatory markers in macular edema (ME) secondary to retinal vein occlusion (RVO) with and without serous retinal detachment (SRD).

MATERIALS-METHODS

Treatment-naive patients with ME secondary to RVO were divided into two groups according to the existence of SRD in optical coherence tomography (OCT) images; group 1 consisted of 60 patients with SRD, and group 2 consisted of 60 patients without SRD. Age and gender-matched 60 patients formed group 3 as healthy controls. Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic inflammation index (SII) were calculated from blood samples to assess the differences in the levels of blood-derived inflammatory markers and the presence of SRD.

RESULTS

The PLR, NLR, and SII values were higher in groups 1 and 2 than in group 3 (p<0.05, each comparison). The NLR and SII values were also significantly elevated in group 1 compared to group 2 (p = 0.000 and p = 0.000, respectively). The optimal cutoff value to estimate SRD in patients with ME secondary to RVO for NLR was 2.08 with 66.7% sensitivity and 65% specificity; for SII was 530.93 with 68.3% sensitivity and specificity.

CONCLUSION

SII is a reliable and cost-effective tool for predicting SRD, an inflammatory OCT biomarker in ME secondary to RVO.

Evaluation of sphingolipid metabolism on diabetic retinopathy

Purpose:

To evaluate the aqueous and serum levels of sphingolipid metabolism mediators such as sphingosine 1 phosphate (S1P), sphingosine kinase 1 (SK1), sphingosine kinase 2 (SK2), ceramide kinase (CK), and acid sphingomyelinase (ASM) which are thought to take part in diabetic retinopathy (DR) pathogenesis, and development and severity of diabetic retinopathy (DR) in patients with type 2 diabetes.

Methods:

A prospective cross-sectional study was conducted on type 2 diabetic and control patients who underwent cataract surgery. Three different subgroups, namely, non-diabetic retinopathy (NDR), non-proliferative diabetic retinopathy (NPDR), and proliferative diabetic retinopathy (PDR), were allocated and the S1P, SK1, SK2, CK, and ASM levels in the serum and aqueous humor samples of diabetic and control patients were evaluated. Kolmogorov-Smirnov test, Student's t-test, and Mann-Whitney U test were used for the statistical analysis of the study.

Results:

Among a total of 45 patients, including diabetic and control patients, the mean aqueous levels of SK1 (P < 0.001), SK2 (P = 0.012), ASM (P = 0.006), and CK (P = 0.002) were higher in all diabetic patients. The mean aqueous level of S1P was significantly higher in the PDR group than in other groups (P = 0.003). The mean aqueous levels of SK2 and ASM also increased in the NDR, NPDR, and PDR subgroups, respectively (P < 0.001). In addition, the mean serum levels of S1P, SK1, and ASM were higher in the diabetic patients (P = 0.015, P = 0.034, and P = 0.006, respectively).

Conclusion:

According to our findings, both aqueous and serum levels of S1P, SK1, and ASM and only the aqueous levels of SK2 and CK were higher in diabetic patients. This study suggested that sphingolipid metabolism may play an important role in DR pathogenesis.

Evaluation of the correlation between quantitative measurement of the foveal avascular zone and retinal vessel density and outer retinal disruptions in diabetic patients

Background/aim

The aim of the current study was to evaluate the correlation between the integrity of the outer retinal layers on optical coherence tomography (OCT) and objective parameters of retinal microvascular perfusion on optical coherence tomography angiography (OCTA).

Materials and methods

A total of 105 eyes of 54 diabetic patients were included in the study. Integrity of the outer retinal layers including the external limiting membrane (ELM), ellipsoid zone (EZ), and interdigitation zone (IZ) was assessed by spectral-domain optical coherence tomography. The foveal avascular zone (FAZ) area and vessel density (VD) measurements in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in all the Early Treatment Diabetic Retinopathy Study (ETDRS) sectors were evaluated by OCTA. Associations between the quantitative measurement of the FAZ and retinal VD measurements and outer retinal disruptions were evaluated.

Results

The FAZ area was correlated with outer retinal layer disruption both in the superficial plexus (r = 0.244, 0.228, 0.212, P = 0.013, 0.02, 0.031 for the ELM, EZ, and IZ, respectively) and the deep capillary plexus (r = 0.298, 0.234, 0.197, P = 0.002, 0.019, 0.048 for the ELM, EZ, and IZ, respectively). A significant relationship was also found between the VD measurements in the SCP and DCP in ETDRS sectors and the outer retinal layers disruption.

Conclusion

The results of the current study show a significant relationship between the quantitative OCTA parameters and the integrity of the outer retinal layers. This finding reveals a correlation between retinal capillary nonperfusion and outer retinal disruption in eyes with diabetic retinopathy.

The levels of the circulating cellular adhesion molecules ICAM-1, VCAM-1 and endothelin-1 and the flow-mediated vasodilatation values in patients with type 1 diabetes mellitus with early-stage diabetic retinopathy

OBJECTIVE

Endothelial dysfunction plays an important role in the development of diabetic retinopathy. The aim of this study was to evaluate endothelial dysfunction using different approaches in patients with type 1 diabete mellitus with early stages of diabetic retinopathy. For this purpose, we investigated the serum levels of cellular adhesion molecules, including intercellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1) and endothelin-1 (ET-1), which have emerged as specific markers of endothelial dysfunction, and measured the flow-mediated dilatation (FMD), a noninvasive technique used to evaluate endothelial dysfunction.

METHODS

The study group included 59 patients with type 1 diabetes mellitus (DM) and 30 age-matched healthy control subjects. The diabetic patients were divided into two groups according to the ophthalmoscopic findings: Group 1, composed of type 1 diabetic patients having no signs of diabetic retinopathy (DRP), and Group 2, composed of type 1 diabetic patients having findings of the early stages of nonproliferative diabetic retinopathy (NPDR).

RESULTS

The serum levels of ET-1 (fmol/mL), ICAM-1 (ng/mL) and VCAM-1 (ng/mL) were 8.52±0.699 vs. 478.39±46.22 vs. 728.64±35.081 in the patients without retinopathy, 8.91±1.354 vs. 451.79±48.262 vs. 863.59±62.37 in the diabetic patients with NPDR and 10.73±1.04 vs. 608.15±74.92 vs. 872.95±57.63 in the control group. There were no significant differences in the serum levels of the three molecules between the groups. The FMD values were 6.51±0.46% in the diabetic patients without retinopathy, 6.66±0.29% in the diabetic patients with NPDR and 6.68±0.51% in the control group. No significant differences were found between the groups.

CONCLUSION

The early stages of diabetic retinopathy cannot be considered in the evaluation of systemic markers of endothelial dysfunction.

Examination of the personalities and anxiety levels of children in prison: a sample of crime in Muğla, Turkey

Child crime and their feelings of guilt have special importance because of their impact on children's development and future life. In the last few years, the number of young and child criminals has increased in Turkey. The sample for this study is from Düğerek prison in Muğla, one of the cities of the Aegean region of Turkey, from 18 February 2007 to 22 February 2007. The sampling group was randomly chosen and consisted of 41 boys aged 15-18 from the child section of the prison. There were no girls in that section. After a one-to-one oral interview with the children, a questionnaire containing the Cornell Index, Inertial Anxiety Inventory and demographic questions was administered. There was a highly positive, meaningful relationship (r: 0.771, P < 0.05) between state anxiety and trait anxiety levels. Our recommendation is that juvenile delinquents need more psychological support than their peers with normal lives, so in order to rehabilitate them, the number of the psychologists should be increased in this prison.