Role of innate immunity and oxidative stress in steroid-induced cataracts in developing chick embryos

Novel molecular, structural and clinical findings in an Italian cohort of congenital cataract

The current genetic diagnostic workup of congenital cataract (CC) is mainly based on NGS panels, whereas exome sequencing (ES) has occasionally been employed. In this multicentre study, we investigated by ES the detection yield, mutational spectrum and genotype-phenotype correlations in a CC cohort recruited between 2020 and mid-2022. The cohort consisted of 67 affected individuals from 51 unrelated families and included both non-syndromic (75%) and syndromic (25%) phenotypes, with extra-CC ocular/visual features present in both groups (48% and 76%, respectively). The functional effect of variants was predicted by 3D modelling and hydropathy properties changes. Variant clustering was used for the in-depth assessment of genotype-phenotype correlations. A diagnostic (pathogenic or likely pathogenic) variant was identified in 19 out of 51 probands/families (~37%). In a further 14 probands/families a candidate variant was identified: in 12 families a VUS was detected, of which 9 were considered plausibly pathogenic (i.e., 4 or 5 points according to ACMG criteria), while in 2 probands ES identified a single variant in an autosomal recessive gene associated with CC. Eighteen probands/families, manifesting primarily non-syndromic CC (15/18, 83%), remained unsolved. The identified variants (8 P, 12 LP, 10 VUS-PP, and 5 VUS), half of which were unreported in the literature, affected five functional categories of genes involved in transcription/splicing, lens formation/homeostasis (i.e., crystallin genes), membrane signalling, cell-cell interaction, and immune response. A phenotype-specific variant clustering was observed in four genes (KIF1A, MAF, PAX6, SPTAN1), whereas variable expressivity and potential phenotypic expansion in two (BCOR, NHS) and five genes (CWC27, KIF1A, IFIH1, PAX6, SPTAN1), respectively. Finally, ES allowed to detect variants in six genes not commonly included in commercial CC panels. These findings broaden the genotype-phenotype correlations in one of the largest CC cohorts tested by ES, providing novel insights into the underlying pathogenetic mechanisms and emphasising the power of ES as first-tier test.

Anti-Cataract Effect of the Traditional Aqueous Extract of Yerba Mate (Ilex paraguariensis A. St.-Hil.): An In Ovo Perspective

INTRODUCTION

The therapeutic effect of different doses of the traditional aqueous extract of dried leaves of yerba mate (Ilex paraguariensis A. St.-Hil.) was investigated in an experimental cataract model in chicken embryos.

METHODS AND RESULTS

LC-MS/MS analysis allowed the identification and quantification of 53 metabolites. In the hydrocortisone-induced cataract model, lenses were examined morphologically after treatment and parameters related to oxidative stress (total antioxidant/oxidant status (TAS/TOS), glutathione (GSH), and malondialdehyde (MDA)) were evaluated. Antiproliferative cell nuclear antigen (PCNA) and caspase-3 H-scores were determined and crystallin alpha A (CRYAA) gene expression in the lenses was measured by RT-PCR. The degree of cataract decreased in all treatment groups. While there was no significant difference in TAS levels compared to the negative control, TOS, GSH, and MDA levels were dose-dependently regulated. Treatment groups other than the high-dose group regulated the decrease in PCNA and the increase in caspase-3. CRYAA gene expression increased significantly only at the lowest dose.

CONCLUSION

YM, which is becoming increasingly popular as a traditional tea, showed a therapeutic effect on hydrocortisone-induced cataracts in chicken embryos at relatively low doses.

Effects of vitamin E in a glucocorticoid induced cataract model in chicken embryos

We investigated the antioxidant effects of vitamin E on a glucocorticoid (GC) induced model of cataracts in chick embryos. We used 70 fertilized eggs divided into seven groups as follows: phosphate-buffered saline (PBS) group, olive oil treatment (OO) group, hydrocortisone treatment (HC) group, olive oil and hydrocortisone treatment (OO + HC) group, 50 mg/kg vitamin E and hydrocortisone treatment (HC + VE (50)) group, 25 mg/kg vitamin E and hydrocortisone treatment (HC + VE (25)) group and 15 mg/kg vitamin E and hydrocortisone treatment (HC + VE (15)) group. On day 17, chick embryos were removed from the eggs and lens and liver tissues were excised. Cataract formation was evaluated and total antioxidant status (TAS), total oxidant status (TOS), malondialdehyde (MDA) and glutathione peroxidase (GPx) were measured in lens and liver tissues; MDA was measured only in liver. The lenses in the HC + VE (50) group exhibited significantly higher levels of GPx and TAS, and lower levels of TOS than for HC and OO + HC groups. The livers of the HC + VE (50) group exhibited significantly higher levels of GPx and lower levels of MDA than for the HC and OO + HC groups. The HC + VE (50) group lenses were evaluated as grade 1, because the nuclei were completely free of cataracts, likely due to the antioxidative effect of high dose VE. VE is an effective antioxidant agent that exhibits a dose-response effect, for ameliorating the negative effects of GCs.

Ozone treatment for high-dose systemic Steroid-Induced retinal injury

OBJECTIVE

To investigate the effect of high-dose systemic steroids on retinal tissues and the effectiveness of ozone (O3) therapy.

METHODS

Twenty-four New Zealand white rabbits were divided into three groups of eight. Group 1 was accepted as the control group, Group 2 received intramuscular 20 mg/kg methylprednisolone acetate and Group 3 received 14 sessions of ozone treatment in addition to methylprednisolone acetate. The subjects were sacrificed on the 30th day. Retinal tissues were removed. Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), total antioxidant status (TAS) and total oxidant status (TOS) levels were evaluated for tissue biochemistry and serum ischaemic modified albumin (IMA), interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) levels were evaluated with the ELISA method. Haematoxylin-eosin staining and TUNEL evaluation for apoptosis were evaluated as histopathological methods.

RESULTS

In the treatment group, antioxidant parameters of TAS, SOD and CAT were higher, oxidative and ischaemic parameters of MDA, TOS and IMA were lower, inflammatory parameters of IL-6 and TNF-α were lower, retinal thickness was better and apoptosis amount was lower.

CONCLUSION

Apoptosis increases in retinal tissues due to high dose systemic steroid administration and the retina becomes thinner. With biochemical examination, oxidation parameters increased while antioxidant parameters decreased. Both histopathological and biochemical parameters improved significantly with ozone treatment.

Antioxidant effects of piperine in in-vivo chick embryo cataract model induced by steroids

PURPOSE

The etiopathogenesis of steroid-induced cataracts is unknown. One hypothesis is that the higher reactive oxygen species (ROS) levels play an important role in the pathogenesis of several disorders, including the evolution of cataracts. This study investigated the antioxidant effects of piperine in our steroid-induced chick embryo lens model.

METHODS

The study included 36 specific pathogen-free (SPF) fertilized eggs divided into six groups: phosphate buffer saline (PBS, pH 7.4 Saline Solution (0.9%) isotonic) group (G1), hydrocortisone succinate sodium (HC)-treated group (G2), 100 mg/kg piperine and HC treated group (G3), 50 mg/kg piperine and HC treated group (G4), 25 mg/kg piperine and HC treated group (G5), and 10 mg/kg piperine and HC treated group (G6). On the 15th day of incubation, the SPF eggs in the six groups were removed from the incubator; all were injected using insulin injectors into the chorioallantoic membrane. On day 17, all of the chick embryos were removed from the eggs and all lenses were dissected from the embryos. Cataract formation was evaluated in all lenses, and total antioxidant status (TAS), total oxidant status (TOS), reduced glutathione (GSH), and lipid peroxidation (MDA, malondialdehyde) levels were measured in all lens.

RESULTS

The lenses in the G1 group had higher levels of GSH and TAS (p < 0.01), and lower levels of MDA and TOS than the G2 group (p < 0.05 and p < 0.01, respectively). Group 3 had higher levels of GSH and TAS (p < 0.001 and p < 0.001 respectively), and lower levels of MDA and TOS than the G2 group (p < 0.01 and p < 0.001, respectively).

CONCLUSION

Steroid therapy causes a decrease in GSH and TAS levels and an increase in TOS and MDA levels in lens tissues, indicating increased oxidative stress. Piperine exerts its effects as an antioxidant substance, in increasing doses.