Diabetic cataract-pathogenesis, epidemiology and treatment. J Ophthalmol. 2010;2010:608751. [PMID: 20634936 PMCID: PMC2903955 DOI: 10.1155/2010/608751]

Global trends in diabetic eye disease research from 2012 to 2021

JOURNAL/nrgr/04.03/01300535-202410000-00032/figure1/v/2024-02-06T055622Z/r/image-tiff Diabetic eye disease refers to a group of eye complications that occur in diabetic patients and include diabetic retinopathy, diabetic macular edema, diabetic cataracts, and diabetic glaucoma. However, the global epidemiology of these conditions has not been well characterized. In this study, we collected information on diabetic eye disease-related research grants from seven representative countries--the United States, China, Japan, the United Kingdom, Spain, Germany, and France--by searching for all global diabetic eye disease journal articles in the Web of Science and PubMed databases, all global registered clinical trials in the ClinicalTrials database, and new drugs approved by the United States, China, Japan, and EU agencies from 2012 to 2021. During this time period, diabetic retinopathy accounted for the vast majority (89.53%) of the 2288 government research grants that were funded to investigate diabetic eye disease, followed by diabetic macular edema (9.27%). The United States granted the most research funding for diabetic eye disease out of the seven countries assessed. The research objectives of grants focusing on diabetic retinopathy and diabetic macular edema differed by country. Additionally, the United States was dominant in terms of research output, publishing 17.53% of global papers about diabetic eye disease and receiving 22.58% of total citations. The United States and the United Kingdom led international collaborations in research into diabetic eye disease. Of the 415 clinical trials that we identified, diabetic macular edema was the major disease that was targeted for drug development (58.19%). Approximately half of the trials (49.13%) pertained to angiogenesis. However, few drugs were approved for ophthalmic (40 out of 1830; 2.19%) and diabetic eye disease (3 out of 1830; 0.02%) applications. Our findings show that basic and translational research related to diabetic eye disease in the past decade has not been highly active, and has yielded few new treatment methods and newly approved drugs.

Dichloroacetate ameliorates apoptosis, EMT and oxidative stress in diabetic cataract via inhibiting the IDO1-dependent p38 MAPK pathway

As an oral antidiabetic agent, dichloroacetate (DCA) has been proven to improve diabetes and related complications. However, its functional role in diabetic cataract (DC) remains to be elucidated. This study was to define the role of DCA and its underlying molecular mechanism in DC in vitro and in vivo. In this study, it was shown that DCA dose-dependently ameliorated DC formation and development in DM rats. In addition, DCA significantly increased cell viability, reduced apoptosis, and inhibited EMT and oxidative stress of high glucose (HG)-treated SRA-01/04 cells in a concentration-dependent manner. Besides, it was revealed that Indoleamine 2,3-dioxygenase 1 (IDO1) expression was upregulated in lenses of DM rats and HG-treated SRA-01/04 cells, which was reversed by DCA. In addition, DCA abrogated the activation of the p38 MAPK signaling in the lenses of DM rats and HG-treated SRA-01/04 cells. Further experiments showed that IDO1 upregulation activated the p38 MAPK signaling in HG-challenged SRA-01/04 cells. Moreover, IDO1 overexpression partially reversed DCA-mediated inactivation of p38 MAPK signaling and suppression of HG-induced damage to SRA-01/04 cells. To sum up, our findings showed that DCA prevented DC-related apoptosis, EMT, and oxidative stress via inactivating IDO1-dependent p38 MAPK signaling.

Potential therapeutic effects of green tea (Camellia sinensis) in eye diseases, a review

This review aims to evaluate the therapeutic potential of green tea (GT), scientifically named Camellia sinensis, in treating eye diseases. We provide an overview of the ingredients and traditional use of Camellia sinensis, followed by a detailed discussion of its therapeutic uses in various eye diseases, including ocular surface diseases (allergic diseases, dry eye, pterygium, and infections), cataract, glaucoma, uveitis, retinal diseases, and optic nerve diseases. The pharmacologic activities related to ocular diseases, such as anti-vascular endothelial growth factor, aldose reductase inhibitor activity, anti-bacterial, anti-inflammatory, and antioxidant effects are also explored in this review. The dose and route of administration of GT in various studies are discussed. Safety issues related to the use of GT, such as the side effects associated with high doses and long-term use, are also addressed. The review highlights the potential of GT as a natural therapeutic agent for a variety of ocular diseases. Its various pharmacologic activities make it a promising treatment option. However, more well-designed studies are needed to determine the optimal dose and route of administration and to assess its long-term safety and efficacy. Overall, GT appears to be a promising adjunct therapy for various ocular diseases.

High incidence of sebaceous gland inflammation in aldose reductase-deficient mice

Aldose reductase is a member of the 1B1 subfamily of aldo-keto reductase gene superfamily. The action of aldose reductase (AR) has been implicated in the pathogenesis of a variety of disease states, most notably complications of diabetes mellitus including neuropathy, retinopathy, nephropathy, and cataracts. To explore for mechanistic roles for AR in disease pathogenesis, we established mutant strains produced using Crispr-Cas9 to inactivate the AKR1B3 gene in C57BL6 mice. Phenotyping AR-knock out (ARKO) strains confirmed previous reports of reduced accumulation of tissue sorbitol levels. Lens epithelial cells in ARKO mice showed markedly reduced epithelial-to-mesenchymal transition following lens extraction in a surgical model of cataract and posterior capsule opacification. A previously unreported phenotype of preputial sebaceous gland swelling was observed frequently in male ARKO mice homozygous for the mutant AKR1B3 allele. This condition, which was shown to be accompanied by infiltration of proinflammatory CD3+ lymphocytes, was not observed in WT mice or mice heterozygous for the mutant allele. Despite this condition, reproductive fitness of the ARKO strain was indistinguishable from WT mice housed under identical conditions. These studies establish the utility of a new strain of AKR1B3-null mice created to support mechanistic studies of cataract and diabetic eye disease.

Management after cataract surgery for patients with diabetic retinopathy: a systematic review and meta-analysis

PURPOSE

To evaluate the safety and effectiveness of various treatment modalities in patients with diabetic retinopathy (DR) who underwent cataract surgery.

METHODS

A comprehensive search for randomized controlled trials (RCTs) was conducted using the PubMed, Embase, Cochrane Library, and CNKI databases up to December 22, 2021. The safety and efficacy of treatment modalities were assessed using the risk ratio (RR) to compare the progression of DR and the mean difference to evaluate the best corrected visual acuity (BCVA) and macular thickness (MT).

RESULTS

The meta-analysis of the RCTs revealed that anti-VEGF (anti-vascular endothelial growth factor) drugs significantly reduced the progression of DR [RR: 0.37 (95%CI 0.19, 0.70), P = 0.002] and improved BCVA [mean difference = - 0.06 (- 0.12, - 0.01), P = 0.03] in patients with pre-existing DR who underwent cataract surgery. Steroid drugs also showed a significant reduction in macular thickness [mean difference = - 55.63 (- 90.73, - 20.53), I2 = 56%, P = 0.002] in DR patients two weeks after cataract surgery compared to the control group. The safety profiles of different management options did not differ significantly.

CONCLUSION

The present meta-analysis suggests that anti-VEGF drugs can effectively slow down the progression of diabetic retinopathy, improve BCVA, and reduce MT in DR patients who underwent cataract surgery. Steroid drugs also show promise in reducing MT. However, further studies with larger sample sizes are required to compare the efficacy and safety of different management options in a multi-center clinical setting.

Macrophakia: The characterization of a novel lens condition

Purpose

To present a novel characterization of a lens condition termed macrophakia which includes large or proportionally large lenses with shallow anterior chamber dimensions that are statistically deviant of a normal population.

Observations

We identified five eyes from three cases to have significantly large lens parameters and small anterior chamber depths. In all five eyes, the anterior chamber depth was less than 2 mm and the anterior chamber depth to lens thickness ratio was two standard deviations outside the normative range of lens and chamber measurements. These large lenses were all observed in the absence of typical pathology and other biometric abnormalities.

Conclusions and importance

A novel lens characterization termed macrophakia is proposed to describe large or proportionately large lenses. Naming this condition is clinically relevant and will enhance cataract evaluations and patient education.

Inhibitory effect of Nifedipine on aldose reductase delays cataract progression

Aldose reductase (ALR2) is a rate-limiting component of the polyol pathway, which is essential for the NADPH-mediated conversion from glucose to sorbitol. ALR2 dysregulation has been linked to α-crystallin aggregation, increased oxidative stress, and calcium inflow, all of which contribute to a diabetic cataract. Given its crucial role in occular pathologies, ALR2 has emerged as a promising target to treat oxidative stress and hyperglycaemic condition which form the underlying cause of diabetic cataracts. However, several of them had issues with sensitivity and specificity to ALR2, despite being screened as effective ALR2 inhibitors from a wide range of structurally varied molecules. The current study investigates the inhibitory potential of Nifedipine, an analog of the dihydro nicotinamide class of compounds against ALR2 activity. The enzyme inhibition studies were supported by in vitro biomolecular interactions, molecular modeling approaches, and in vivo validation in diabetic rat models. Nifedipine demonstrated appreciable inhibitory potential with the purified recombinant hAR (human aldose reductase; with an IC50 value of 2.5 µM), which was further supported by Nifedipine-hAR binding affinity (Kd = 2.91 ± 1.87 × 10-4 M) by ITC and fluorescence quenching assays. In the in vivo models of STZ-induced diabetic rats, Nifedipine delayed the onset progression of cataracts by preserving the antioxidant enzyme activity (SOD, CAT, and GPX GSH, TBARS, and protein carbonyls) and was shown to retain the α-crystallin chaperone activity by reducing the calcium levels in the diabetic rat lens. In conclusion, our results demonstrate effective inhibition of ALR2 by Nifedipine, resulting in amelioration of diabetic cataract conditions by lowering oxidative and osmotic stress while retaining the chaperone activity of α-crystallins. The present study could be envisaged to improve the eye condition in older adults upon Nifedipine treatment.

Fennel Essential Oil as a Complementary Therapy in the Management of Diabetes

Diabetes is a serious pathology that affects a significant number of people worldwide. Its progression is rapid and leads to serious complications if glycemic control is missing. The micro and macrovascular complications of diabetes produce disabilities over time that affect the daily lives of patients. The major challenge of diabetes therapy is to reach a stable glycemic state and to delay the onset of specific complications. Aromatherapy is considered an alternative or complementary therapy, but in recent years, there has been a tendency to overuse essential oils. The present study was designed to evaluate and compare the effects produced by the topical and oral administration of fennel essential oil to diabetic rats. Eighteen compounds in fennel essential oil were identified by gas chromatography-mass spectrometry (GC-MS) analysis. The major compounds were trans-anethole (64.6%) and fenchone (24.5%). The in vivo study revealed that after a four-week treatment with fennel essential oil, the rats' glycemic levels were significantly reduced (p ≤ 0.05). Furthermore, there were no differences between the two routes of administration. In addition, an ex vivo study underlined the potential effect of this essential oil in the prevention of cataract formation.

Dissecting causal associations of type 2 diabetes with 111 types of ocular conditions: a Mendelian randomization study

Background

Despite the well-established findings of a higher incidence of retina-related eye diseases in patients with diabetes, there is less investigation into the causal relationship between diabetes and non-retinal eye conditions, such as age-related cataracts and glaucoma.

Methods

We performed Mendelian randomization (MR) analysis to examine the causal relationship between type 2 diabetes mellitus (T2DM) and 111 ocular diseases. We employed a set of 184 single nucleotide polymorphisms (SNPs) that reached genome-wide significance as instrumental variables (IVs). The primary analysis utilized the inverse variance-weighted (IVW) method, with MR-Egger and weighted median (WM) methods serving as supplementary analyses.

Results

The results revealed suggestive positive causal relationships between T2DM and various ocular conditions, including "Senile cataract" (OR= 1.07; 95% CI: 1.03, 1.11; P=7.77×10-4), "Glaucoma" (OR= 1.08; 95% CI: 1.02, 1.13; P=4.81×10-3), and "Disorders of optic nerve and visual pathways" (OR= 1.10; 95% CI: 0.99, 1.23; P=7.01×10-2).

Conclusion

Our evidence supports a causal relationship between T2DM and specific ocular disorders. This provides a basis for further research on the importance of T2DM management and prevention strategies in maintaining ocular health.

Macular changes following cataract surgery in eyes with early diabetic retinopathy: an OCT and OCT angiography study

Background

To evaluate changes in macular status and choroidal thickness (CT) following phacoemulsification in patients with mild to moderate nonproliferative diabetic retinopathy (NPDR) using optical coherence tomography.

Methods

In this prospective study, all of the patients underwent uncomplicated phacoemulsification. Retinal superficial capillary plexus vascular density (SCP-VD), macular thickness (MT), and CT were measured pre- and postoperatively.

Results

Twenty-two eyes of 22 cataract patients with mild to moderate NPDR without diabetic macular edema (DME) and 22 controls were enrolled. BCVA increased in two groups at 3 months postoperatively. At 1 and 3 months postoperatively, SCP-VD in the diabetic retinopathy (DR) group significantly increased; changes in SCP-VD in parafovea were significantly greater in the DR group than in the control group. MT and CT in the DR group significantly increased at all visits postoperatively in the fovea and perifovea. Changes in parafoveal MT were significantly greater in the DR group than in the control group at all visits postoperatively. Changes in CT and MT in the fovea were significantly greater in patients with DR than in the controls 1 and 3 months postoperatively.

Conclusion

Uncomplicated phacoemulsification resulted in greater increases in SCP-VD, MT and CT in patients with early DR without preoperative DME than in controls.

KLF5/MDM2 Axis Modulates Oxidative Stress and Epithelial-Mesenchymal Transition in Human Lens Epithelial Cells: The Role in Diabetic Cataract

Diabetic cataract (DC) is a common cause of visual loss in older diabetic subjects. Krüppel-like factor 5 (KLF5) plays an essential role in migration and the epithelial-mesenchymal transition (EMT) in diverse cells and is involved in oxidative stress. However, the effects of KLF5 on DC remain unknown. This study aimed to examine the biological function of KLF5 in DC and its underlying mechanism. The expression patterns of KLF5 were detected in vivo and in vitro. Then, KLF5 was knocked down in human lens epithelial cells (HLECs) to explore its functional roles and underlying mechanisms. Dual-luciferase reporter assay and chromatin immunoprecipitation analysis were used to detect whether KLF5 could bind the promoter of E3 ubiquitin ligase mouse double minute 2 (MDM2), a key regulator of EMT. Lastly, the regulation of KLF5 in the biological behaviors of HLECs via MDM2 was analyzed. We found a significant increase of KLF5 in the DC lens anterior capsular, diabetic rat lens, and high glucose (HG)-stimulated HLECs. Knockdown of KLF5 inhibited oxidative stress, inflammation, migration, and EMT of HG-stimulated HLECs. KLF5 silencing impeded MDM2 expression and restricted the activation of MARK1/FAK and NF-κB signaling pathways in HLECs under HG condition. Additionally, KLF5 was found to bind the MDM2 promoter and enhance the transcriptional activity of MDM2. The protective effects by silencing KLF5 on HG-cultured HLECs could be offset by MDM2 overexpression. We demonstrated that knockdown of KLF5 alleviated oxidative stress, migration, and EMT of HG-cultured HLECs by regulating MDM2, suggesting a potential therapeutic strategy for DC.

Effects of Angiotensin Receptor Blockers on Streptozotocin-Induced Diabetic Cataracts

This study aimed to determine the role of oxidative stress produced by the renin-angiotensin system (RAS) in cataract formation in streptozotocin-induced diabetic rats (STZ) using angiotensin II receptor blockers (ARBs). Rats were treated with streptozotocin and orally administered candesartan (2.5 mg/kg/day) or a normal diet for 10 weeks until sacrifice. Cataract progression was assessed through a slit-lamp examination. Animals were euthanized at 18 weeks, and the degree of cataract progression was evaluated. Oxidative stress was also assessed. In STZ-treated rats, lens opacity occurred at 12 weeks. Cataract progression was inhibited in the ARB-treated group compared with the placebo group (p < 0.05). STZ-treated rats exhibited upregulated angiotensin-converting enzyme (ACE) gene expression than control rats. Oxidative stress-related factors were upregulated in the placebo-treated group but suppressed in the ARB-treated group. A correlation coefficient test revealed a positive correlation between ACE gene expression and oxidative stress-related factors and a negative correlation between ACE and superoxide dismutase. Immunostaining revealed oxidative stress-related factors and advanced glycation end products in the lens cortex of the placebo-treated group. The mechanism of diabetic cataracts may be related to RAS, and the increase in focal ACE and angiotensin II in the lens promotes oxidative stress-related factor production.

Attenuation of epithelial-mesenchymal transition via SGLT2 inhibition and diabetic cataract suppression by dapagliflozin nanoparticles treatment

AIMS

Chronic hyperglycemia triggers overproduction of AKR1B1 (aldo-keto reductase family 1 member B) and receptor for advanced glycation end product (RAGE), which causes epithelial-mesenchymal transition (EMT) in the lens epithelial cells (LECs) of diabetic mellitus (DM) cataracts. However, it is unclear whether EMT in LECs is related to abnormal increase of SGLT2. Sodium glucose cotransporter 2 (SGLT2) inhibitor, also known as dapagliflozin (Dapa) can be used to treat diabetes. Here, we examined how Dapa or nano eye-drops (DapaN) reduce EMT in LECs of DM cataracts. The nano eye-drop provides an ophthalmic treatment that suppressed diabetic cataract progression and improved potency with reduced side effects.

MAIN METHODS

SD rats were injected with streptozocin (STZ) (65 mg/kg, ip), nano-Dapa drops (0.456 mg/10 ml/eye) or Dapa (1.2 mg/kg/day) treatment for 6-12 weeks. Immunofluorescence staining was used for protein quantification of RAGE, SGLT2, N-cadherin and E-cadherin in the LECs of rats.

KEY FINDINGS

In this study, Dapa applies nanotechnology-based delivery system and it contains polyvinylpyrrolidone (PVP) and HPBCD. Dapa showed therapeutic effect on DM cataracts, wherein it targeted EMT biomarker, E-cadherin. The nano-Dapa drops or oral Dapa inhibited SGLT2, suppressed AKR1B1 expression, decreased AcSOD2- and RAGE-induced EMT in diabetic cataracts. Our findings suggest that nanotechnology-based Dapa eye drops (Dapa-PVP-HPBCD) can effectively improve solubility of Dapa in aqueous solution.

SIGNIFICANCE

Taken together, results suggest that the SGLT2-mediated DM cataract therapy may involve the AKR1B1-RAGE-AcSOD2-EMT pathway. The nano eye drops and Dapa show potential beneficial effects for cataract prevention. This study conveys new insights into cataract treatment and supplementation of nano-Dapa drops shows promising result in preventing diabetic cataracts.

Analysis of N6-methyladenosine-modified mRNAs in diabetic cataract

BACKGROUND

Cataracts remain a prime reason for visual disturbance and blindness all over the world, despite the capacity for successful surgical replacement with artificial lenses. Diabetic cataract (DC), a metabolic complication, usually occurs at an earlier age and progresses faster than age-related cataracts. Evidence has linked N6-methyladenosine (m6A) to DC progression. However, there exists a lack of understanding regarding RNA m6A modifications and the role of m6A in DC pathogenesis.

AIM

To elucidate the role played by altered m6A and differentially expressed mRNAs (DEmRNAs) in DC.

METHODS

Anterior lens capsules were collected from the control subjects and patients with DC. M6A epitranscriptomic microarray was performed to investigate the altered m6A modifications and determine the DEmRNAs. Through Gene Ontology and pathway enrichment (Kyoto Encyclopedia of Genes and Genomes) analyses, the potential role played by dysregulated m6A modification was predicted. Real-time polymerase chain reaction was further carried out to identify the dysregulated expression of RNA methyltransferases, demethylases, and readers.

RESULTS

Increased m6A abundance levels were found in the total mRNA of DC samples. Bioinformatics analysis predicted that ferroptosis pathways could be associated with m6A-modified mRNAs. The levels of five methylation-related genes-RBM15, WTAP, ALKBH5, FTO, and YTHDF1-were upregulated in DC samples. Upregulation of RBM15 expression was verified in SRA01/04 cells with high-glucose medium and in samples from DC patients.

CONCLUSION

M6a mRNA modifications may be involved in DC progression via the ferroptosis pathway, rendering novel insights into therapeutic strategies for DC.

REAL WORLD STUDY COMPARING PHAKIC VERSUS PSEUDOPHAKIC EYES IN DIABETIC MACULAR EDEMA TREATED WITH DEXAMETHASONE IMPLANT: The PHAKIDEX Study

PURPOSE

Dexamethasone implant (DEX-implant) is one treatment choice in diabetic macular edema. However, steroid-induced cataract is a common complication when treating a chronic disease and could lead to vision loss. Because of the lack of studies specifically focused on the functional outcomes according to the lens status, the authors therefore aim to analyze the effectiveness and safety of DEX-implant treatment for diabetic macular edema in phakic versus pseudophakic eyes.

METHODS

This multicenter, retrospective study conducted in France included eyes of consecutive patients who had received a DEX-implant for diabetic macular edema.

RESULTS

A total of 328 eyes were included: 158 eyes (48.2%) were phakic, 167 eyes (50.9%) were pseudophakic and three were unknown. According to the lens status, mean change in best-corrected visual acuity from baseline was never significantly different between phakic and pseudophakic eyes (likelihood ratio test, P = 0.09) nor in the change in central macular thickness (likelihood ratio test, P = 0.79) in multivariate analysis. Cataract surgery was performed in 63 phakic eyes (39.9%) during the study period with a mean delay of 8.1 months (CI95% [6.59-9.69]). The mean change in best-corrected visual acuity between phakic eyes who underwent cataract surgery and those who did not, was not significantly different during the follow-up at each visit. The risk of ocular hypertension was not statistically different between phakic and pseudophakic subsets ( P = 0.9).

CONCLUSION

The authors showed here that phakic eyes treated with DEX-implant for diabetic macular edema did not have a significant difference in visual gain in comparison to pseudophakic eyes, with a comparable safety profile.

Enzymatic and biochemical properties of lens in age-related cataract versus diabetic cataract: A narrative review

Cataract is the leading cause of blindness worldwide. There is an increased incidence of cataract formation in the diabetic population due to several factors. Diabetes mellitus accelerates the development of cataract. Oxidative stress results in most of the diabetic complications including diabetic cataract. Oxidative stress leading to the expression of various enzymes has also been proven as crucial for cataractous changes in the lens in old age. A narrative review was undertaken to investigate the expression of different biochemical parameters as well as enzymes in diabetic and senile cataracts. Identification of these parameters is crucial for the prevention and treatment of blindness. Combinations of MeSH terms and key words were used to do literature search in PubMed. The search resulted 35 articles and among them, 13 were relevant to the topic and were included in synthesis of results. Seventeen different types of enzymes were identified in the senile and diabetic cataracts. Seven biochemical parameters were also identified. Alteration in biochemical parameters and expression of enzymes were comparable. Majority of the parameters were raised or altered in diabetic cataract compared to senile cataract.

The role of lutein-rich purple sweet potato leaf extract on the amelioration of diabetic retinopathy in streptozotocin-induced Sprague-Dawley rats

The objective of this study is to access the effect of purple sweet potato leaf (PSPL) extract on diabetic retinopathy (DR) of streptozotocin (STZ)-induced male Sprague-Dawley (SD) rats. In this study, rats were injected intraperitoneally with a single dose of 60 mg/kg STZ, and diabetes was confirmed on day 7. Rats were further divided into a few groups, which were then orally administered with one of the following treatments: 25 mg/kg of gliclazide (D25G), 200 mg/kg of PSPL extract (DT 200), and 400 mg/kg of PSPL extract (DT 400). However, the normal control (NS) and control group for diabetic (DNS) were given normal saline (NS) for 12 weeks. The results show that the treated group demonstrated a reduction in serum oral glucose tolerance test (OGTT) levels of DT 200 and DT 400, and an increase in the serum and retinal insulin levels, and restored oxidative stress markers in serum and retina on week 12. The PSPL extract exhibited protective effects in maintaining the kidney, liver, retina, and pancreas architecture in 400 mg/kg compared to the 200 mg/kg treated group and D25G, thereby restoring fully transparent lenses in diabetes-induced rats. In conclusion, 400 mg/kg PSPL is the most effective dose for the amelioration of STZ-induced DR pathology in male SD rats.

Systemic Anti-Inflammatory Therapy Aided by Curcumin-Laden Double-Headed Nanoparticles Combined with Injectable Long-Acting Insulin in a Rodent Model of Diabetes Eye Disease

Therapeutic interventions that counter emerging targets in diabetes eye diseases are lacking. We hypothesize that a combination therapy targeting inflammation and hyperglycemia can prevent diabetic eye diseases. Here, we report a multipronged approach to prevent diabetic cataracts and retinopathy by combining orally bioavailable curcumin-laden double-headed (two molecules of gambogic acid conjugated to terminal carboxyl groups of poly(d,l-lactide-co-glycolide)) nanoparticles and injectable basal insulin. The combination treatment led to a significant delay in the progression of diabetic cataracts and retinopathy, improving liver function and peripheral glucose homeostasis. We found a concurrent reduction in lens aggregate protein, AGEs, and increased mitochondrial ATP production. Importantly, inhibition of Piezo1 protected against hyperglycemia-induced retinal vascular damage suggesting possible involvement of Piezo1 in the regulation of retinal phototransduction. Histologic evaluation of murine small intestines revealed that chronic administration of curcumin-laden double-headed nanoparticles was well tolerated, circumventing the fear of nanoparticle toxicity. These findings establish the potential of anti-inflammatory and anti-hyperglycemic combination therapy for the prevention of diabetic cataracts and retinopathy.

Current Approach to the Pathogenesis of Diabetic Cataracts

Cataracts remain the first or second leading cause of blindness in all world regions. In the diabetic population, cataracts not only have a 3–5 times higher incidence than in the healthy population but also affect people at a younger age. In patients with type 1 diabetes, cataracts occur on average 20 years earlier than in the non-diabetic population. In addition, the risk of developing cataracts increases with the duration of diabetes and poor metabolic control. A better understanding of the mechanisms leading to the formation of diabetic cataracts enables more effective treatment and a holistic approach to the patient.

Clinical observation of femtosecond laser-assisted cataract surgery for diabetic cataract

OBJECTIVE

To observe the clinical efficacy of femtosecond laser-assisted cataract surgery (FLACS) for diabetic cataract (DC).

METHODS

One hundred and seven cases of DC admitted between August 2018 and August 2021 were enrolled, and their clinical data were retrospectively analyzed. Of them, 53 cases treated with conventional phacoemulsification (Phaco) cataract surgery (CPS) were set as the control group (the Con) and 54 cases receiving FLACS were set as the observation group (the Obs). Clinical data such as effective phaco time (EPT), color doppler energy (CDE), best corrected visual acuity (BCVA), visual quality, corneal endothelial cell (CEC) count (CECC), and complication rate were compared and analyzed. Finally, multivariate Cox regression analysis was performed to analyze the prognostic factors based on the incidence of complications in DC patients.

RESULTS

The Obs had significantly lower EPT and CDE compared to the Con, as well as markedly elevated BCVA and visual quality at one month after operation compared to the preoperative levels and the Con. The CECC of the Obs differed insignificantly from that before surgery and was higher versus the Con. Moreover, the incidence of postoperative complications (corneal edema, fibrin exudation, pigment dispersion, and posterior synechia of the iris) was lower in the Obs. Moreover, the treatment method was an independent prognostic factor affecting the prognosis of DC patients.

CONCLUSIONS

The above analysis suggests the superior efficacy of FLACS to CPS for DC, as it can more significantly reduce EPT, CDE, CEC loss, and the incidence of postoperative complications with a positive effect on improving BCVA, visual quality, and patient prognosis.

Evaluation of Systemic Medications Associated With Surgically Treated Cataract Among US Adults

PURPOSE

To comprehensively determine the associations between systemic medications and surgically treated cataract in the US population.

DESIGNS

Retrospective cross-sectional study.

METHODS

Participants aged ≥40 years from the 1999-2008 National Health and Nutrition Examination Survey (NHANES) were included. Surgically treated cataract was defined as cataract requiring a procedure. Data on prescription drug use over the past 30 days were collected via home interviews. Drug categories for ophthalmic indications and those prescribed in less than 0.5% of the participants were excluded from the analysis. Separate logistic regression models were used to explore associations between each drug category and surgically treated cataract. The Benjamin-Hochberg procedure was used to control the false discovery rate.

RESULTS

A total of 14,931 were included in the present analysis. The weighted prevalence of surgically treated cataract was 9.6% (n=2010). We identified 20 drug categories that had significant associations with surgically treated cataract, of which 8 associations remained statistically significant after further adjustment for pertinent comorbidities. The 3 drug categories with the highest odds ratio (OR) values were tricyclic antidepressants (OR, 2.21; 95% CI, 1.38-3.51; P = .001), insulin (OR, 2.13; 95% CI, 1.48-3.07; P = 9.41×10^-5) and group III antiarrhythmic agents (OR, 2.00; 95% CI, 1.25-3.19; P = .004). The use of sex hormone combinations among women reduced the risk of having surgically treated cataract (OR, 0.011; 95% CI, 0.001-0.089; P = 5.98×10^-5). Dose-response relationships were observed for all 8 drug categories.

CONCLUSIONS

Our comprehensive evaluation provides new knowledge on the complex relationships between systemic medications and surgically treated cataract.

Optimizing treatment for diabetic macular edema during cataract surgery

Diabetic macular edema (DME) causes visual impairment in diabetic retinopathy (DR). Diabetes mellitus is a global epidemic and diabetic individuals are at risk of developing DR. Approximately 1 in 10 diabetic patients suffers from DME, which is the commonest cause of vision-threatening DR at primary-care screening. Furthermore, diabetes predisposes to a higher frequency and a younger onset of cataract, which further threatens vision in DME patients. Although cataract extraction is an effective cure, vision may still deteriorate following cataract surgery due to DME progression or recurrence, of which the risks are significantly higher than for patients without concurrent or previous history of DME at the time of operation. The management of pre-existing DME with visually significant cataract is a clinical conundrum. Deferring cataract surgery until DME is adequately treated is not ideal because of prolonged visual impairment and maturation of cataract jeopardizing surgical safety and monitoring of DR. On the other hand, the progression or recurrence of DME following prompt cataract surgery is a profound disappointment for patients and ophthalmic surgeons who had high expectations for postoperative visual improvement. Prescription of perioperative anti-inflammatory eye drops is effective in lowering the risk of new-onset DME after cataract surgery. However, management of concurrent DME at the time of cataract surgery is much more challenging because DME is unlikely to resolve spontaneously even with the aid of anti-inflammatory non-steroidal or steroid eye drops. A number of clinical trials using intravitreal injection of corticosteroids and anti-vascular endothelial growth factor (anti-VEGF) as first-line therapy have demonstrated safety and efficacy to treat DME. These drugs have also been administered perioperatively for the prevention of DME worsening in patients undergoing cataract surgery. This article reviews the scientific evidence to guide ophthalmologists on the efficacy and safety of various therapies for managing patients with DME who are particularly vulnerable to cataract surgery-induced inflammation, which disintegrates the blood-retinal barrier and egression of fluid in macular edema.

Evaluation of Macular Thickness Changes after Uncomplicated Phacoemulsification Surgery in Healthy Subjects and Diabetic Patients without Retinopathy by Spectral Domain OCT

PURPOSE

To assess differences in the evolution of macular thickness after uncomplicated phacoemulsification surgery between non-diabetic subjects and patients with diabetes mellitus (DM) without diabetic retinopathy (DR), using Spectral Domain OCT (SD-OCT).

METHODS

We performed a unicentric prospective study including one hundred and thirty-one eyes of 70 patients divided into two groups-34 well-controlled DM patients without DR and 36 non-diabetic subjects-who underwent phacoemulsification for cataract surgery. Eyes that developed pseudophakic cystoid macular edema (PCME) were excluded from the study, leaving us with 64 patients. Macular thickness was analyzed using Cirrus HD-OCT (Macular Cube 512 × 128 protocol) preoperatively and on postoperative days 7, 30, 90, and 180. For cases with information available for both eyes, one eye was randomly selected for analysis.

RESULTS

A total of 64 eyes from 64 patients were analyzed in this study. The mean value of HbA1c in the diabetic group was 7%. After uncomplicated cataract surgery, patients showed no increase of the foveal, parafoveal, and perifoveal retinal thickness on postoperative day 7. However, thickness values increased on days 30, 90, and 180 after surgery in both groups, and peak at 90 days. There was no difference in macular thickness before or after surgery between DM and non-diabetic patients (p = 0.540).

CONCLUSION

Macular thickness increases up to 6 months after uncomplicated cataract surgery in both DM patients without DR and non-diabetic subjects, with no differences between increases in both groups.

Alcohol use patterns and risk of incident cataract surgery: a large scale case-control study in Japan

To examine the risk of incident cataract surgery associated with alcohol use patterns among Japanese adults. This was a case-control study evaluating 14,861 patients with incident cataract surgery and 14,861 matched controls. Subjects admitted to any of the 34 hospitals in Japan and aged between 40 and 69 years were included. Drinking patterns (drinking frequency, daily average drinks, and total amount of lifetime drinking), smoking history, lifestyle-related comorbidities, and occupational factors were surveyed by trained interviewers. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression models. For drinking frequency, ORs in the 1-3 days/week and 4-7 days/week groups were 1.10 (95% CI 1.03-1.17) and 1.30 (1.21-1.40), respectively. For average drinks, ORs in > 0-2 drinks/day, > 2-4 drinks/day, and > 4 drinks/day were 1.13 (1.06-1.20), 1.23 (1.12-1.35), and 1.16 (1.03-1.31), respectively. Both men and women had an increased risk of incident cataract surgery with increased total lifetime drinking, with a significant increase in risk occurring at > 90 drink-years for men and > 40 drink-years for women. A positive dose-response relationship was observed between alcohol consumption and cataract. Restricted drinking may help to reduce the progression of cataracts.

Study of the Natural Crystalline Lens Characteristics Using Dual-Energy Computed Tomography

There is a paucity of radiologic literature regarding age-related cataract, and little is known about any differences in the imaging appearance of the natural crystalline lens on computed tomography (CT) exams among different demographic groups. In this retrospective review of 198 eyes in 103 adults who underwent dual-energy computed tomography (DECT) exams of the head, regions of interest spanning 3−5 mm were placed over the center of the lens, and the x-ray attenuation of each lens was recorded in Hounsfield Units (HU) at 3 energy levels: 40 keV, 70 keV, and 190 keV. Generalized estimating equations (GEEs) were used to assess the association of clinical or demographic data with lens attenuation. The mean HU values were significantly lower for the older vs. younger group at 40 keV (GEE p-value = 0.022), but there was no significant difference at higher energy levels (p > 0.05). Mean HU values were significantly higher for females vs. males and non-whites vs. non-Hispanic whites at all 3 energy levels in bivariate and multivariable analyses (all p-value < 0.05). There was no significant association between lens attenuation and either diabetes or smoking status. The crystalline lens of females and non-whites had higher attenuation on DECT which may suggest higher density or increased concentration of materials like calcium and increased potential for cataract formation. Given the large scope of cataracts as a cause of visual impairment and the racial disparities that exist in its detection and treatment, further investigation into the role of opportunistic imaging to detect cataract formation is warranted.

Circadian rhythms-related disorders in diurnal fat sand rats under modern lifestyle conditions: A review

Modern lifestyle reduces environmental rhythmicity and may lead to circadian desynchrony. We are exposed to poor day-time lighting indoors and excessive night-time artificial light. We use air-conditioning to reduce ambient temperature cycle, and food is regularly available at all times. These disruptions of daily rhythms may lead to type 2 diabetes mellitus (T2DM), obesity, cardiometabolic diseases (CMD), depression and anxiety, all of which impose major public health and economic burden on societies. Therefore, we need appropriate animal models to gain a better understanding of their etiologic mechanisms, prevention, and management.We argue that the fat sand rat (Psammomys obesus), a diurnal animal model, is most suitable for studying the effects of modern-life conditions. Numerous attributes make it an excellent model to study human health disorders including T2DM, CMD, depression and anxiety. Here we review a comprehensive series of studies we and others conducted, utilizing the fat sand rat to study the underlying interactions between biological rhythms and health. Understanding these interactions will help deciphering the biological basis of these diseases, which often occur concurrently. We found that when kept in the laboratory (compared with natural and semi-wild outdoors conditions where they are diurnal), fat sand rats show low amplitude, nocturnal or arrhythmic activity patterns, dampened daily glucose rhythm, glucose intolerance, obesity and decreased survival rates. Short photoperiod acclimation exacerbates these pathologies and further dampens behavioral and molecular daily rhythms, resulting in CMD, T2DM, obesity, adipocyte dysfunction, cataracts, depression and anxiety. Increasing environmental rhythmicity by morning bright light exposure or by access to running wheels strengthens daily rhythms, and results in higher peak-to-trough difference in activity, better rhythmicity in clock genes expression, lower blood glucose and insulin levels, improved glucose tolerance, lower body and heart weight, and lower anxiety and depression. In summary, we have demonstrated that fat sand rats living under the correspondent of “human modern lifestyle” conditions exhibit dampened behavioral and biological rhythms and develop circadian desynchrony, which leads to what we have named “The Circadian Syndrome”. Environmental manipulations that increase rhythmicity result in improvement or prevention of these pathologies. Similar interventions in human subjects could have the same positive results and further research on this should be undertaken.

Noncoding RNAs in cataract formation: star molecules emerge in an endless stream

For decades, research on the pathological mechanism of cataracts has usually focused on the abnormal protein changes caused by a series of risk factors. However, an entire class of molecules, termed non-coding RNA (ncRNA), was discovered in recent years and proven to be heavily involved in cataract formation. Recent studies have recognized the key regulatory roles of ncRNAs in cataracts by shaping cellular activities such as proliferation, apoptosis, migration and epithelial-mesenchymal transition (EMT). This review summarizes our current insight into the biogenesis, properties and functions of ncRNAs and then discusses the development of research on ncRNAs in cataracts. Considering the significant role of ncRNA in cataract formation, research on novel associated regulatory mechanisms is urgently needed, and the development of therapeutic alternatives for the treatment of cataracts seems promising.

The Possible Positive Mechanisms of Pirenoxine in Cataract Formation

Cataract is the leading cause of blindness worldwide. A diverse range of medication has been invented to prevent or treat cataract. Pirenoxine (PRX), a drug with strong antioxidant properties, has been used topically to treat cataract, and there is much evidence to demonstrate the beneficial effects of PRX on lens opacity from in vitro and in vivo models. In clinical use, PRX has been prescribed worldwide by ophthalmologists for over six decades; however, there is still controversy with regard to its efficacy, and thus PRX remains an off-label use for cataract treatment. This comprehensive review summarizes and discusses evidence pertinent to the mechanisms of PRX and its efficacy mainly on cataract models. The issues that have been deemed uncertain over the six-decade use of PRX are examined. The information summarized in this review should provide insights into contriving novel approaches for the treatment of cataract.

Some sulfonamides as aldose reductase inhibitors: therapeutic approach in diabetes

In this study, aldose reductase (AR) was purified from sheep kidney using chromatographic methods and examined the interactions between some sulfonamides and the enzyme. According to results, sulfonamides display effective inhibitor features for sheep kidney AR with IC₅₀ values in the range of 37.27-87.65 μM and K_is in the range of 25.72 ± 6.45 to 73.56 ± 17.49 μM. The sulfonamides displayed different inhibition mechanisms. It was found that studied all compounds displayed non-competitive inhibition type except for 5-chlorothiophene-2-sulfonamide (1). It showed competitive inhibition. Among these compounds, 2,5-dichlorothiophene-3-sulfonamide compound (2) was showed the most potent AR inhibitor (K_i: 25.72 ± 6.45). These compounds may be useful in the treatment of diabetic complications.

Blocking of SGLT2 to Eliminate NADPH-Induced Oxidative Stress in Lenses of Animals with Fructose-Induced Diabetes Mellitus

Chronic hyperglycemia triggers an abnormal rise in reactive oxygen species (ROS) that leads to blindness in patients with diabetes mellitus (DM) and cataracts. In this study, the effects of dapagliflozin, metformin and resveratrol on ROS production were investigated in lens epithelial cells (LECs) of animals with fructose-induced DM. LECs were isolated from patients without DM, or with DM devoid of diabetic retinopathy. Animals were treated with 10% fructose for 8 weeks to induce DM, which was verified by monitoring blood pressure and serum parameters. For drug treatments, 1.2 mg/day of dapagliflozin was given for 2 weeks, 500 mg/kg/day of metformin was given, and 10 mg/kg/day of resveratrol was given. Dihydroethidium was used to stain endogenous O2˙− production in vivo of the LECs. Superoxide production was expressed in the cataract of DM, or patients without DM. Sodium–glucose cotransporter 2 (SGLT2), glucose transporter 1 (GLUT1), GLUT5, the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit p47/p67-phox, NOX4 and RAGE were significantly increased in LECs with DM. In addition, the dapagliflozin treatment reduced GLUT5, p47/p67-phox, NADPH oxidase 4 (NOX4) and receptor for advanced glycation end products (RAGE) expressions. On the contrary, metformin or resveratrol inhibited p47-phox, GLUT5, and SGLT2 expressions, but not nuclear factor erythroid 2–related factor 2 (NRF2). In summary, dapagliflozin, metformin or resveratrol down-regulated p47-phox expression through SGLT2 inactivation and ROS reduction. These important findings imply that SGLT2 can be blocked to ameliorate oxidative stress in the cataracts of DM patients.

TFEB-Mediated Lysosomal Restoration Alleviates High Glucose-Induced Cataracts Via Attenuating Oxidative Stress

Purpose

Diabetic cataract (DC) is a visual disorder arising from diabetes mellitus (DM). Autophagy, a prosurvival intracellular process through lysosomal fusion and degradation, has been implicated in multiple diabetic complications. Herein, we performed in vivo and in vitro assays to explore the specific roles of the autophagy-lysosome pathway in DC.

Methods

Streptozotocin-induced DM and incubation in high glucose (HG) led to rat lens opacification. Protein Simple Wes, Western blot, and immunoassay were utilized to investigate autophagic changes in lens epithelial cells (LECs) and lens fiber cells (LFCs). RNA-sequencing (RNA-seq) was performed to explore genetic changes in the lenses of diabetic rats. Moreover, autophagy-lysosomal functions were examined using lysotracker, Western blot, and immunofluorescence analyses in HG-cultured primary rabbit LECs.

Results

First, DM and HG culture led to fibrotic LECs, swelling LFCs, and eventually cataracts. Further analysis showed aberrant autophagic degradation in LECs and LFCs during cataract formation. RNA-seq data revealed that the differentially expressed genes (DEGs) were enriched in the lysosome pathway. In primary LECs, HG treatment resulted in decreased transcription factor EB (TFEB) and cathepsin B (CTSB) activity, and increased lysosomal size and pH values. Moreover, TFEB-mediated dysfunctional lysosomes resulted from excessive oxidative stress in LECs under HG conditions. Furthermore, TFEB activation by curcumin analog C1 alleviated HG-induced cataracts through enhancing lysosome biogenesis and activating protective autophagy, thereby attenuating HG-mediated oxidative damage.

Conclusions

In summary, we first identified that ROS-TFEB-dependent lysosomal dysfunction contributed to autophagy blockage in HG-induced cataracts. Additionally, TFEB-mediated lysosomal restoration might be a promising therapeutic method for preventing and treating DC through mitigating oxidative stress.

Natural aldose reductase inhibitors for treatment and prevention of diabetic cataract: A review

Introduction: Aldose reductase (AR) is an enzyme that catalyzes the reduction of glucose to sorbitol responsible for the development of diabetic complications like cataracts. Medicinal plants contain several phytocompounds that can inhibit this enzyme.

Objective: The purpose of this review is to cite medicinal plants that have been tested for their ability to inhibit aldose reductase and consequently prevent cataracts and classify the major isolated compounds that have this activity.

Methods: We reviewed 154 articles published between 1954 and 2020 in English via three databases: ScienceDirect, Web of Science, and PubMed. We have classified the plants that showed a significant anti-cataract effect, in the form of a list including the scientific and family names of each plant. Also, we have cited the IC50 values and the active constituents of each plant that showed inhibitory activity towards AR.

Results: We have described 38 herbs belonging to 29 families. Besides, 47 isolated compounds obtained from the cited herbs have shown an AR inhibitory effect: luteolin, luteolin-7-O-β-D-glucopyranoside, apigenin, 3,5-di-O-caffeoyl-epi-quinic acid, delphinidin 3-O-β-galactopyranoside-3’-O-β-glucopyranoside, 3,5-di-O-caffeoylquinic acid methyl ester, andrographolide, 1,2,3,6-tetra-O-galloyl-β-D-glucose, 1,2,4,6-tetra-O-galloyl-β-D-glucose, 7-(3-hydroxypropyl)-3-methyl-8-β-O-D-glucoside-2H-chromen-2-one, E-4-(60-hydroxyhex-30-en-1-yl)phenyl propionate, delphinidin 3-O-β-galactopyranoside-3’,5’-di-O-β-glucopyranoside, 1,2,3-tri-O-galloyl-β-D-glucose, 1,2,3,4,6-penta-O-galloyl-β-D-glucose, 1,2,6-tri-O-galloyl-β-D-glucose, 2-(4-hydroxy-3-methoxyphenyl)ethanol, (4-hydroxy-3-methoxyphenyl)methanol, trans-anethole, gallic acid 4-O-β-D-(6’-O-galloyl)-glucoside, β-glucogallin, puerariafuran, quercetin, gallic acid 4-O-β-D-glucoside, 2,5-dihydroxybenzoic acid, 4-(4-hydroxy-3-methoxyphenyl)-2-butanone, protocatechuic acid, trans-cinnamic acid, gallic acid, p-coumaric acid and syringic acid.

Conclusion: natural therapy becomes an interesting alternative in the treatment and prevention of cataract by using medicinal plants rich in active compounds considered as AR inhibitors.

MDM2-mediated ubiquitination of LKB1 contributes to the development of diabetic cataract

Diabetic cataract (DC) is a common complication of diabetes mellitus. The epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) is a crucial event in the development of DC. Murine double minute 2 (MDM2) is an E3 ubiquitin ligase that promotes EMT by regulating diverse targets. However, little is known about how MDM2 is involved in the pathogenesis of DC. We found the mRNA and protein levels of MDM2 were up-regulated in the lens of DC patients and rats. Thus, high glucose (HG)-induced human lens epithelial cells (HLECs) were constructed for further investigation. The results showed that the level of MDM2 was increased in HG-cultured HLECs, and the MDM2 knockdown alleviated HG-induced abnormal migration, EMT, and oxidative stress damage. Moreover, co-immunoprecipitation and ubiquitination assays demonstrated that MDM2 down-regulated LKB1 expression by ubiquitination degradation. LKB1 was found to be lower expressed in human and rat DC lenses, and HG-stimulated HLECs. Also, LKB1 overexpression mitigated HG-induced dysfunction of HLECs. Finally, our data showed that the changes related to EMT and oxidative stress induced by MDM2 knockdown were restored by down-regulation of LKB1. Together, MDM2 may involve in the pathogenesis of DC through down-regulating LKB1. MDM2 might be an effective therapeutical target of DC.

Cataract in children and adolescents with type 1 diabetes. Insights from the German/Austrian DPV registry

OBJECTIVE

To study diabetic cataract in type 1 diabetes in a large pediatric cohort.

METHODS

The 92,633 patients aged 0.5-21 years from German/Austrian multicenter diabetes registry (DPV) were analyzed. The 235 patients (0.25%) with diabetic cataract were found, 200 could be categorized: 67 with early cataract (3 months before diabetes onset - 12 months afterwards), 133 with late cataract (>12 months after diabetes onset). Regression models adjusted for age and gender were used to compare clinical parameters at diabetes onset. Regression models for patients with late cataract were implemented for the total documentation period and additionally adjusted for diabetes duration.

RESULTS

Rate of cataract development shows a peak at diabetes onset and declines with longer diabetes duration. Patients with cataract showed strong female preponderance. Patients developing early cataract were older at diabetes onset (12.8 years [11.8/13.9] vs. 8.9 [8.9/9.0]; p < 0.001) and showed higher HbA1c than patients without cataract (9.0% [8.55/9.38] vs. 7.6% [7.60/7.61]; p < 0.001). They had lower height-SDS, (-0.22 [-0.48/0.04] vs. 0.25 [0.24/0.26]; p < 0.001), lower weight-SDS (-0.31 [-0.55/-0.08] vs. 0.21 [0.20/0.21]; p < 0.001) and lower BMI-SDS (-0.25 [-0.49/-0.02] vs. 0.12 [0.12/0.13); p = 0.002). Patients with late cataract showed higher HbA1c at diabetes onset (8.35% [8.08/8.62] vs. 8.04% [8.03/8.05]; p = 0.023) and higher mean HbA1c during total documentation period (8.00% [7.62/8.34] vs. 7.62% [7.61/7.63]; p = 0.048).

CONCLUSIONS

Our data confirm known demographic and clinical characteristics of patients developing early cataract. Hyperglycemia-induced osmotic damage to lens fibers at diabetes onset might be the main pathomechanism. Long term glycemic control is associated with cataract development.

The Association Between Glycaemic Control, Renal Function and Post-operative Ophthalmic Complications in People With Diabetes Undergoing Cataract Surgery-A Single-Centre Retrospective Analysis

INTRODUCTION

In general surgery, it has been shown that poor peri-operative diabetes control, as measured by glycated haemoglobin (HbA_1c), is associated with adverse post-operative outcomes. National data for the UK suggest that the post-operative complication rate for cataract surgery is 2.8%. It is unknown whether people with diabetes who undergo cataract surgery are also at increased risk.

METHODS

This single-centre retrospective study looked at the association of peri-operative HbA_1c and estimated glomerular filtration rate (eGFR) with the risk of post-operative complications in people undergoing phacoemulsification and intraocular lens implantation under local anaesthesia during 2016.

RESULTS

4401 individuals had cataract surgery. Of these, 34.6% (1525) had diabetes. Of those with diabetes, 114 (7.5%) developed a post-operative ophthalmological complication (as defined by the Royal College of Ophthalmologists) necessitating at least one eye clinic appointment. Mean HbA_1c did not differ between those who did and those who did not develop complications (52 vs 50 mmol/mol, p = 0.12). After adjustment, HbA_1c was not a significant risk (OR 1.00; 95% CI: 0.99-1.05; p = 0.85). However, eGFR had a small but statistically significant effect on outcome (OR 0.99; 95% CI: 0.98-1.00; p = 0.02).

CONCLUSIONS

This study has shown that more people who undergo cataract surgery have diabetes than previously reported. Also, people with diabetes are at higher risk of developing complications than previously reported. HbA_1c concentration was not a factor in these adverse post-operative outcomes. However, eGFR was a predictor of risk. More focus should be placed on pre-operatively optimising co-morbidities than diabetes control in those undergoing cataract surgery.

Paeoniflorin inhibits epithelial mesenchymal transformation and oxidative damage of lens epithelial cells in diabetic cataract via sirtuin 1 upregulation

Paeoniflorin (Pae) has been reported to serve an important role in complications associated with diabetes. To the best of our knowledge, the role of Pae in diabetic cataracts has not yet been reported. Human lens epithelial SRA01/04 cells were induced by high glucose (HG) and subsequently treated with Pae. Cell viability was detected using the MTT assay. Moreover, LDH levels were detected. Immunofluorescence (IF) and Western blotting were used to determine the protein expression levels of N-cadherin and E-cadherin. ELISA was performed to determine oxidative stress-related indicator levels. TUNEL and Western blotting detected the apoptotic rate. The mRNA and protein expression levels of sirtuin 1 (SIRT1) in SRA01/04 cells were measured via reverse transcription-quantitative PCR and Western blotting, respectively. Subsequently, cell transfection techniques were used to inhibit the expression of SIRT1 in cells. MTT, ELISA, IF, Western blotting and TUNEL assays were used to investigate the mechanisms of epithelial-mesenchymal transition (EMT) and oxidative damage with Pae in the diabetic cataract. Pae significantly increased cell viability and possibly inhibit the EMT and oxidative damage of SRA01/04 cells induced by HG. Pae was demonstrated to upregulate SIRT1 expression levels. The results therefore suggested that the downregulation of SIRT1 reversed the protective effect of Pae on EMT and oxidative damage in SRA01/04 cells induced by HG. In conclusion, Pae may inhibit EMT of lens epithelial cells and reduce oxidative damage in diabetic cataracts via the upregulation of SIRT1.

Peperomia pellucida (L.) Kunth and eye diseases: A review on phytochemistry, pharmacology and toxicology

Peperomia pellucida (L.) Kunth is a medicinal plant used to manage inflammatory illnesses such as conjunctivitis, and gastrointestinal and respiratory tract disorders in tropical and subtropical regions. However, little is known about its pharmacological mechanism of action against eye diseases. This review aims to critically discuss the phytochemistry, pharmacology and toxicology of P. pellucida as well as its roles in the treatment of cataract, glaucoma and diabetic retinopathy. Recent developments in the uses of P. pellucida for healthcare and nutraceutical products by the pharmaceutical industry are also covered in this review. For this review, a literature search was performed with PubMed, ScienceDirect, SciFinder Scholar and Scopus databases, using relevant keywords. Among the various phytochemicals identified from P. pellucida, β-caryophyllene, carotol, dillapiole, ellagic acid, pellucidin A, phytol and vitexin exhibit strong pharmacological activities within the mitogen-activated protein kinase and nuclear factor-κB signalling pathways in inflammatory eye diseases. The antihypertensive, anti-inflammatory, antioxidant, antihyperglycemic and anti-angiogenic activities displayed by P. pellucida extracts in many in vitro, in vivo and clinical studies suggest its potential role in the management of inflammatory eye diseases. P. pellucida extract was non-toxic against normal cell lines but displayed mild toxicity in animal models. The growing public interest in P. pellucida has inspired the nutraceutical and pharmaceutical industries to process the plant into health products. Although the potential pharmacological mechanisms against eye diseases have been summarized, further studies of the interactions among constituent phytochemicals from P. pellucida within various signalling pathways shall support the use of the plant as an alternative therapeutic source.

The impact of concurrent training and antioxidant supplementation on the factors associated with the ocular lens opacity in diabetic rats

The current study was aimed to investigate the protective effect of vitamins C and E (VCE) supplementation, exercise, and their concurrent application against cataract incidence in the diabetic rats. The obtained results indicated that different supplementation and training treatments were capable to preserve the lens transparency in the diabetic rats. Also, upon applying different supplementation and training treatments, the level of glutathione (GSH) and activity of antioxidant enzymes in the diabetic rats was preserved approximately close to their control levels. In addition, different treatments were capable to maintain the structural integrity of the lens proteins in diabetic rats. Moreover, VCE supplementation, exercise and their simultaneous application prevented lens crystallins of diabetic rats against fibrillation and formation of the increased oligomeric sizes. The results of this study signify the importance of antioxidant supplementation and exercise in reducing the detrimental effects of hyperglycemia on the eye lenses.

Progression to severe visual impairment and blindness in POAG patients: pace and risk factors—a cohort study using German health claims data

Objective

Glaucoma is a leading cause of severe visual impairment and blindness (SVI/B) worldwide. Hence, it is of utmost importance to explore relevant risk factors and study the pace of progression to SVI/B.

Methods and analysis

We used a random sample of 250 000 persons from administrative individual-level health records of the Allgemeine Ortskrankenkassen between 2004 and 2015. We identified 3535 primary open-angle glaucoma (POAG) patients aged 55 and older and followed them for up to 10 years. Monocular and binocular SVI/B were defined by the ICD-10 classifications H54.0 and H54.4. Ophthalmological and chronic disease risk factors were analysed by applying a multivariable Cox proportional hazard model.

Results

The risk of SVI/B in POAG patients was significantly increased by the presence of specific additional eye diseases such as secondary glaucoma (HR: 3.08, p<0.001), retinal vascular occlusion (HR: 3.00, p<0.001) or age-related macular degeneration (AMD) (HR: 2.26, p<0.001). The risk was highest in the first 2 years after the POAG diagnosis and significantly decreased after the fifth year (HR: 0.36, p=0.002). Ocular injuries, other ocular diseases, non-ophthalmological comorbidities, and age and sex had no significant influence (p>0.05).

Conclusion

Although progression to SVI/B is relatively rare in POAG patients in Germany, one must be aware of additional risk factors, such as secondary glaucoma, retinal vascular occlusion and AMD. Regular ophthalmological examinations help prevent the progression of SVI/B, especially in the first years after the POAG diagnosis. Specific, targeted, and timely treatments for the other eye diseases could help prevent or delay SVI/B.

Genistein-Opportunities Related to an Interesting Molecule of Natural Origin

Nowadays, increasingly more attention is being paid to a holistic approach to health, in which diet contributes to disease prevention. There is growing interest in functional food that not only provides basic nutrition but has also been demonstrated to be an opportunity for the prevention of disorders. A promising functional food is soybean, which is the richest source of the isoflavone, genistein. Genistein may be useful in the prevention and treatment of such disorders as psoriasis, cataracts, cystic fibrosis, non-alcoholic fatty liver disease and type 2 diabetes. However, achievable concentrations of genistein in humans are low, and the use of soybean as a functional food is not devoid of concerns, which are related to genistein's potential side effects resulting from its estrogenic and goitrogenic effects.

Relationship Between SGLT-2i and Ocular Diseases in Patients With Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

This meta-analysis was conducted to explore the association between sodium-glucose cotransporter 2 inhibitors (SGLT-2is) and ocular diseases in type 2 diabetes mellitus (T2DM) patients.

METHODS

PubMed, Cochrane Central Registry of Controlled Trials, Web of Science and Springer were searched for articles on randomized controlled trials (RCTs) involving T2DM patients treated with SGLT-2i versus placebo or other hypoglycemic agents published prior to August 2021. The primary outcome of this meta-analysis was incidence of ocular diseases, which was assessed using risk ratios (RR) and 95% confidence intervals (CI). We reviewed 47 papers and compared the effect of SGLT-2i with the effect of the control groups (placebo and other hypoglycemic drugs) on the incidence of ocular diseases.

RESULTS

Compared with controls, overall SGLT-2i use in T2DM patients was not associated with incidences of cataract, glaucoma, retinal disease and vitreous disease. Ertugliflozin (RR=0.47, P=0.01) reduced the risk for retinal disease, while empagliflozin (RR=0.44, P=0.05) reduced the risk for diabetic retinopathy (DR) compared with controls. SGLT-2i (RR=0.50, P=0.02), perhaps empagliflozin (RR=0.47, P=0.06), reduced the risk of retinal disease compared with active hypoglycemic agents. Canagliflozin (RR=4.50, P=0.03) increased the risk for vitreous disease compared with placebo.

CONCLUSIONS

There was no significant correlation between overall SGLT-2i and ocular diseases (cataract, glaucoma, retinal disease, vitreous disease, corneal disease, conjunctival disease, uveal disease, eye haemorrhage and vision problems) in T2DM patients. Ertugliflozin and empagliflozin may protect against ocular diseases, but canagliflozin may promote ocular diseases.

Senile Cataract in Patients with Diabetes with and Without Diabetic Retinopathy: A Community-Based Comparative Study

Aim

We compare the incidence rates of cataract in persons with diabetes with and without diabetic retinopathy in Saudi Arabia, for the first time. In addition, we explored the role of new factor, diabetes age of onset and several other known factors.

Methods

In a community-based cross-sectional study, 334 persons with diabetes type 2 were randomly selected from a diabetic register. Detailed history and comprehensive ophthalmic examination was done at an eye clinic. Body Mass Index, blood pressure and glycosylated hemoglobin were also recorded.

Results

In 668 eyes, cataract and diabetic retinopathy were present in 35.5% and 32.2%, respectively. Diabetic retinopathy, age, duration of diabetes and systolic BP were found to be independent risk factors for cataract. Whereas, gender, BMI, HbA1c use of insulin and diastolic BP have no significant association with cataract. Persons with cataract had significantly higher age of onset of diabetes. Most of the cataracts were cortical followed by PSC, while minority were nuclear.

Conclusion

DR is an independent risk factor of developing cataract in persons with diabetes. Others are age, duration of DM and hypertension. Age-of-onset of DM is a new factor we report it to be significantly associated with cataract.

Comparison of methods to experimentally induce opacification and elasticity change in ex vivo porcine lenses

At the moment, cataract, which is the opacification of the eye’s lens, can only be treated by surgery. In order to develop and test new pharmacological treatment strategies for the disease, there is a need for an appropriate in vitro model using ex vivo animal lenses. In this study, porcine lenses were incubated in either culture medium, glucose, triamcinolone acetonide, sodium chloride, hydrogen peroxide, sodium selenite, neutral buffered formalin, or were exposed to microwave heating to experimentally induce lens opacification. Changes in the lens morphology, weight, size, and elasticity were monitored 7 days after treatment. The fastest induction of dense opacification was seen in lenses exposed to sodium chloride, neutral buffered formalin, and microwave heating. No change in the size and weight of the lenses were detected, whereas loss in elasticity could be detected in lenses treated with formalin solution or microwave heating. Thus, neutral buffered formalin- and microwave-treated ex vivo porcine lenses seem to be a suitable model for mature cataracts, whereas hypertonic sodium chloride may be useful for studies on osmolarity-induced lens opacification.

lncRNA XIST knockdown suppresses cell proliferation and promotes apoptosis in diabetic cataracts through the miR‑34a/SMAD2 axis

According to emerging evidence, long non-coding RNAs (lncRNAs) play critical roles in diabetes. The aim of the present study was to investigate the role and mechanism of X-inactive specific transcript (XIST) in cell proliferation, migration and apoptosis in diabetic cataracts (DC). SRA01/04 lens epithelial cells were treated with high glucose (HG). The levels of XIST, microRNA (miR)-34a and SMAD family member 2 (SMAD2) were examined via reverse transcription-quantitative PCR. MTT, Transwell, wound healing and TUNEL assays were performed to examine cell proliferation, invasion, migration and apoptosis, respectively. The interaction between miR-34a and XIST or SMAD2 was verified by luciferase reporter assay. It was found that the expression of XIST was increased and that of miR-34a was decreased in DC tissues and HG-treated SRA01/04 cells. XIST knockdown or miR-34a overexpression attenuated cell proliferation and migration, and induced apoptosis in HG-treated SRA01/04 cells. XIST targeted miR-34a and regulated DC progression through miR-34a. SMAD2 was identified as a target gene of miR-34a and was positively modulated by XIST. XIST knockdown inhibited cell proliferation and migration, and accelerated apoptosis in HG-stimulated SRA01/04 cells, and these effects were abrogated by SMAD2 overexpression. In conclusion, XIST promoted cell proliferation, migration and invasion, and inhibited apoptosis, through the miR-34a/SMAD2 axis in DC.

The elevated risk of sight-threatening cataract in diabetes with retinopathy: a retrospective population-based cohort study

Background

The effect of diabetic retinopathy (DR) on the development of sight-threatening cataracts was assessed using the National Health Insurance Research Database of Taiwan.

Methods

Patients diagnosed with diabetes mellitus (DM) and DR were enrolled in the study group. Age- and sex-matched DM individuals without DR and patients without DM served as the DM control group and non-DM control group, respectively, both with 1:4 ratios. The outcome was set as the performance of cataract surgery. Cox proportional hazard regression was used to calculate the adjusted hazard ratio (aHR) of DR considering multiple factors underlying cataract formation.

Results

A total of 3297 DR patients, 13,188 DM control patients and 13,188 non-DM control subjects were enrolled. The study group included 919 events of sight-threatening cataracts (27.87%), the DM control group included 1108 events (8.40%), and the non-DM control group included 957 events (7.26%). A multivariable analysis indicated that the study group presented a higher aHR of cataract surgery (2.93, 95% CI: 2.60–3.30) and a higher cumulative probability of cataract surgery than both the DM control and non-DM control groups (both log rank P < 0.001). In addition, both the proliferative DR (3.90, 95% CI: 3.42–4.45) and nonproliferative DR (2.35, 95% CI: 2.08–2.65) subgroups showed a higher aHR of cataract surgery than the DM control group.

Conclusion

The presence of DR increases the risk of sight-threatening cataracts that warrant surgery, and the effect is prominent among patients with both proliferative DR and nonproliferative DR.

Diabetic eye: associated diseases, drugs in clinic, and role of self-assembled carriers in topical treatment

Introduction: Diabetes is a pandemic disease that causes relevant ocular pathologies. Diabetic retinopathy, macular edema, cataracts, glaucoma, or keratopathy strongly impact the quality of life of the patients. In addition to glycemic control, intense research is devoted to finding more efficient ocular drugs and improved delivery systems that can overcome eye barriers. Areas covered: The aim of this review is to revisit first the role of diabetes in the development of chronic eye diseases. Then, commercially available drugs and new candidates in clinical trials are tackled together with the pros and cons of their administration routes. Subsequent sections deal with self-assembled drug carriers suitable for eye instillation combining patient-friendly administration with high ocular bioavailability. Performance of topically administered polymeric micelles, liposomes, and niosomes for the management of diabetic eye diseases is analyzed in the light of ex vivo and in vivo results and outcomes of clinical trials. Expert opinion: Self-assembled carriers are being shown useful for efficient delivery of not only a variety of small drugs but also macromolecules (e.g. antibodies) and genes. Successful design of drug carriers may offer alternatives to intraocular injections and improve the treatment of both anterior and posterior segments diabetic eye diseases.