An Overview of the Eye in Diabetes

Clinic-oriented injectable smart material for the treatment of diabetic wounds: Coordinating the release of GM-CSF and VEGF

Chronic wounds are often caused by diabetes and present a challenging clinical problem due to vascular problems leading to ischemia. This inhibits proper wound healing by delaying inflammatory responses and angiogenesis. To address this problem, we have developed injectable particle-loaded hydrogels which sequentially release Granulocyte-macrophage- colony-stimulating-factor (GM-CSF) and Vascular endothelial growth factor (VEGF) encapsulated in polycaprolactone-lecithin-geleol mono-diglyceride hybrid particles. GM-CSF promotes inflammation, while VEGF facilitates angiogenesis. The hybrid particles (200-1000 nm) designed within the scope of the study can encapsulate the model proteins Bovine Serum Albumin 65 ± 5 % and Lysozyme 77 ± 10 % and can release stably for 21 days. In vivo tests and histological findings revealed that in the hydrogels containing GM-CSF/VEGF-loaded hybrid particles, wound depth decreased, inflammation phase increased, and fibrotic scar tissue decreased, while mature granulation tissue was formed on day 10. These findings confirm that the hybrid particles first initiate the inflammation phase by delivering GM-CSF, followed by VEGF, increasing the number of vascularization and thus increasing the healing rate of wounds. We emphasize the importance of multi-component and sequential release in wound healing and propose a unifying therapeutic strategy to sequentially deliver ligands targeting wound healing stages, which is very important in the treatment of the diabetic wounds.

Follow-up in a point-of-care diabetic retinopathy program in Pittsburgh: a non-concurrent retrospective cohort study

BACKGROUND

The Point-of-Care Diabetic Retinopathy Examination Program (POCDREP) was initiated in 2015 at the University of Pittsburgh/UPMC in response to low diabetic retinopathy (DR) examination rates, a condition affecting a quarter of people with diabetes mellitus (PwDM) and leading to blindness. Early detection and treatment are critical with DR prevalence projected to triple by 2050. Approximately, half of PwDM in the U.S. undergo yearly examinations, and there are reported varying follow-up rates with eye care professionals, with limited data on the factors influencing these trends. POCDREP aimed to address screening and follow-up gap, partnering with diverse healthcare entities, including primary care sites, free clinics, and federally qualified health centers.

METHODS

A non-concurrent retrospective cohort study spanning 2015-2018 examined data using electronic health records of patients who underwent retinal imaging. Imaging was performed using 31 cameras across various settings, with results interpreted by ophthalmologists. Follow-up recommendations were made for cases with vision-threatening DR (VTDR), incidental findings, or indeterminate results. Factors influencing follow-up were analyzed, including demographic, clinical, and imaging-related variables. We assessed the findings at follow-up of patients with indeterminate results.

RESULTS

Out of 7,733 examinations (6,242 patients), 32.25% were recommended for follow-up. Among these, 5.57% were classified as having VTDR, 14.34% had other ocular findings such as suspected glaucoma and age-related macular degeneration (AMD), and 12.13% were indeterminate. Of those recommended for follow-up, only 30.87% were assessed by eye care within six months. Older age, marriage, and severe DR were associated with higher odds of following up. Almost two thirds (64.35%) of the patients with indeterminate exams were found with a vision-threatening disease at follow-up.

CONCLUSION

The six-month follow-up rate was found to be suboptimal. Influential factors for follow-up included age, marital status, and the severity of diabetic retinopathy (DR). While the program successfully identified a range of ocular conditions, screening initiatives must extend beyond mere disease detection. Ensuring patient follow-up is crucial to DR preventing programs mission. Recommended strategies to improve follow-up adherence include education, incentives, and personalized interventions. Additional research is necessary to pinpoint modifiable factors that impact adherence and to develop targeted interventions.

Comprehensive insights into a decade-long journey: The evolution, impact, and human factors of an asynchronous telemedicine program for diabetic retinopathy screening in Pennsylvania, United States

Diabetic Retinopathy stands as a leading cause of irreversible blindness, necessitating frequent examinations, especially in the early stages where effective treatments are available. However, current examination rates vary widely, ranging from 25-60%. This study scrutinizes the Point-of-Care Diabetic Retinopathy Examination Program at the University of Pittsburgh/UPMC, delving into its composition, evolution, challenges, solutions, and improvement opportunities. Employing a narrative approach, insights are gathered from key stakeholders, including ophthalmologists and staff from primary care clinics. A quantitative analysis from 2008 to 2020 provides a comprehensive overview of program outcomes, covering 94 primary care offices with 51 retinal cameras. Program components feature automated non-mydriatic 45° retinal cameras, a dedicated coordinator, rigorous training, and standardized workflows. Over this period, the program conducted 21,960 exams in 16,458 unique individuals, revealing a diverse population with an average age of 58.5 and a balanced gender distribution. Average body mass index (33.96±8.02 kg/m2) and hemoglobin A1c (7.58%±1.88%) surpassed normal ranges, indicating prevalent risk factors for diabetes-related complications. Notably, 24.2% of patients underwent more than one exam, emphasizing program engagement. Findings indicated that 86.3% of exams were gradable, with 59.0% within normal limits, 12.1% showing some evidence of diabetic retinopathy, and 6.4% exhibiting vision-threatening diabetic retinopathy. Follow-up appointments with ophthalmologists were recommended in 31.5% of exams due to indeterminate results, positive diabetic retinopathy (≥moderate or macular exudate), or other findings like age-related macular degeneration or suspected glaucoma. The program demonstrated high reproducibility across diverse healthcare settings, featuring a sustainable model with minimal camera downtime, standardized workflows, and financial support from grants, health systems, and clinical revenues. Despite COVID-19 pandemic challenges, this research emphasizes the program's reproducibility, user-friendly evolution, and promising outcomes. Beyond technical contributions, it highlights human factors influencing program success. Future research could explore adherence to follow-up ophthalmological recommendations and its associated factors.

Morusacerane: A new gammacerane triterpenoid from the trunk of Morus Alba linn. with α-glucosidase inhibitory activity

This phytochemistry investigation on the trunk of Morus alba L. resulted in the isolation of three triterpenoids, including a new gammacerane triterpenoid - morusacerane (1); along with two known compounds of betulinic acid (2) and ursolic acid (3). The structure elucidation was thoroughly conducted based on 1D, 2D-NMR and HRESIMS spectra, followed by a comparison with existing literatures. The evaluation on α-glucosidase inhibitory exhibited the great potential of the application of these isolated compounds in diabetes treatments. The results show that morusacerane (1), betulinic acid (2), and ursolic acid (3) demonstrate the strong inhibitory with the IC50 values of 106.1, 11.12, and 7.20 μM, respectively. All of these compounds interacted well with the allosteric site enzyme α-glucosidase MAL32 through H-bonds and hydrophobic interaction.

Effects of Diabetes Mellitus on Corneal Immune Cell Activation and the Development of Keratopathy

Diabetes mellitus (DM) is one of the most prevalent diseases globally, and its prevalence is rapidly increasing. Most patients with a long-term history of DM present with some degree of keratopathy (DK). Despite its high incidence, the underlying inflammatory mechanism of DK has not been elucidated yet. For further insights into the underlying immunopathologic processes, we utilized streptozotocin-induced mice to model type 1 DM (T1D) and B6.Cg-Lepob/J mice to model type 2 DM (T2D). We evaluated the animals for the development of clinical manifestations of DK. Four weeks post-induction, the total frequencies of corneal CD45+CD11b+Ly-6G- myeloid cells, with enhanced gene and protein expression levels for the proinflammatory cytokines TNF-α and IL-1β, were higher in both T1D and T2D animals. Additionally, the frequencies of myeloid cells/mm2 in the sub-basal neural plexus (SBNP) were significantly higher in T1D and T2D compared to non-diabetic mice. DK clinical manifestations were observed four weeks post-induction, including significantly lower tear production, corneal sensitivity, and epitheliopathy. Nerve density in the SBNP and intraepithelial terminal endings per 40x field were lower in both models compared to the normal controls. The findings of this study indicate that DM alters the immune quiescent state of the cornea during disease onset, which may be associated with the progressive development of the clinical manifestations of DK.

Effects of hypoxia in the diabetic corneal stroma microenvironment

Corneal dysfunctions associated with Diabetes Mellitus (DM), termed diabetic keratopathy (DK), can cause impaired vision and/or blindness. Hypoxia affects both Type 1 (T1DM) and Type 2 (T2DM) surprisingly, the role of hypoxia in DK is unexplored. The aim of this study was to examine the impact of hypoxia in vitro on primary human corneal stromal cells derived from Healthy (HCFs), and diabetic (T1DMs and T2DMs) subjects, by exposing them to normoxic (21% O2) or hypoxic (2% O2) conditions through 2D and 3D in vitro models. Our data revealed that hypoxia affected T2DMs by slowing their wound healing capacity, leading to significant alterations in oxidative stress-related markers, mitochondrial health, cellular homeostasis, and endoplasmic reticulum health (ER) along with fibrotic development. In T1DMs, hypoxia significantly modulated markers related to membrane permeabilization, oxidative stress via apoptotic marker (BAX), and protein degradation. Hypoxic environment induced oxidative stress (NOQ1 mediated reduction of superoxide in T1DMs and Nrf2 mediated oxidative stress in T2DMs), modulation in mitochondrial health (Heat shock protein 27 (HSP27), and dysregulation of cellular homeostasis (HSP90) in both T1DMs and T2DMs. This data underscores the significant impact of hypoxia on the diabetic cornea. Further studies are warranted to delineate the complex interactions.

Exploring exercise-driven inhibition of pyroptosis: novel insights into treating diabetes mellitus and its complications

Diabetes mellitus (DM) and its complications are important, worldwide public health issues, exerting detrimental effects on human health and diminishing both quality of life and lifespan. Pyroptosis, as a new form of programmed cell death, plays a critical role in DM and its complications. Exercise has been shown to be an effective treatment for improving insulin sensitivity or preventing DM. However, the molecular mechanisms underlying the effects of exercise on pyroptosis-related diseases remain elusive. In this review, we provided a comprehensive elucidation of the molecular mechanisms underlying pyroptosis and the potential mechanism of exercise in the treatment of DM and its complications through the modulation of anti-pyroptosis-associated inflammasome pathways. Based on the existing evidence, further investigation into the mechanisms by which exercise inhibits pyroptosis through the regulation of inflammasome pathways holds promising potential for expanding preventive and therapeutic strategies for DM and facilitating the development of novel therapeutic interventions.

TFOS Lifestyle: Impact of nutrition on the ocular surface

Nutrients, required by human bodies to perform life-sustaining functions, are obtained from the diet. They are broadly classified into macronutrients (carbohydrates, lipids, and proteins), micronutrients (vitamins and minerals) and water. All nutrients serve as a source of energy, provide structural support to the body and/or regulate the chemical processes of the body. Food and drinks also consist of non-nutrients that may be beneficial (e.g., antioxidants) or harmful (e.g., dyes or preservatives added to processed foods) to the body and the ocular surface. There is also a complex interplay between systemic disorders and an individual's nutritional status. Changes in the gut microbiome may lead to alterations at the ocular surface. Poor nutrition may exacerbate select systemic conditions. Similarly, certain systemic conditions may affect the uptake, processing and distribution of nutrients by the body. These disorders may lead to deficiencies in micro- and macro-nutrients that are important in maintaining ocular surface health. Medications used to treat these conditions may also cause ocular surface changes. The prevalence of nutrition-related chronic diseases is climbing worldwide. This report sought to review the evidence supporting the impact of nutrition on the ocular surface, either directly or as a consequence of the chronic diseases that result. To address a key question, a systematic review investigated the effects of intentional food restriction on ocular surface health; of the 25 included studies, most investigated Ramadan fasting (56%), followed by bariatric surgery (16%), anorexia nervosa (16%), but none were judged to be of high quality, with no randomized-controlled trials.

Computational intelligence in eye disease diagnosis: a comparative study

In recent years, eye disorders are an important health issue among older people. Generally, individuals with eye diseases are unaware of the gradual growth of symptoms. Therefore, routine eye examinations are required for early diagnosis. Usually, eye disorders are identified by an ophthalmologist via a slit-lamp investigation. Slit-lamp interpretations are inadequate due to the differences in the analytical skills of the ophthalmologist, inconsistency in eye disorder analysis, and record maintenance issues. Therefore, digital images of an eye and computational intelligence (CI)-based approaches are preferred as assistive methods for eye disease diagnosis. A comparative study of CI-based decision support models for eye disorder diagnosis is presented in this paper. The CI-based decision support systems used for eye abnormalities diagnosis were grouped as anterior and retinal eye abnormalities diagnostic systems, and numerous algorithms used for diagnosing the eye abnormalities were also briefed. Various eye imaging modalities, pre-processing methods such as reflection removal, contrast enhancement, region of interest segmentation methods, and public eye image databases used for CI-based eye disease diagnosis system development were also discussed in this paper. In this comparative study, the reliability of various CI-based systems used for anterior eye and retinal disorder diagnosis was compared based on the precision, sensitivity, and specificity in eye disease diagnosis. The outcomes of the comparative analysis indicate that the CI-based anterior and retinal disease diagnosis systems attained significant prediction accuracy. Hence, these CI-based diagnosis systems can be used in clinics to reduce the burden on physicians, minimize fatigue-related misdetection, and take precise clinical decisions.

Animal models of diabetic microvascular complications: Relevance to clinical features

Diabetes has become more common in recent years worldwide, and this growth is projected to continue in the future. The primary concern with diabetes is developing various complications, which significantly contribute to the disease's mortality and morbidity. Over time, the condition progresses from the pre-diabetic to the diabetic stage and then to the development of complications. Years and enormous resources are required to evaluate pharmacological interventions to prevent or delay the progression of disease or complications in humans. Appropriate screening models are required to gain a better understanding of both pathogenesis and potential therapeutic agents. Different species of animals are used to evaluate the pharmacological potentials and study the pathogenesis of the disease. Animal models are essential for research because they represent most of the structural, functional, and biochemical characteristics of human diseases. An ideal screening model should mimic the pathogenesis of the disease with identifiable characteristics. A thorough understanding of animal models is required for the experimental design to select an appropriate model. Each animal model has certain advantages and limitations. The present manuscript describes the animal models and their diagnostic characteristics to evaluate microvascular diabetic complications.

Comprehensive Proteomic Profiling of Aqueous Humor Proteins in Proliferative Diabetic Retinopathy

Purpose

Proliferative diabetic retinopathy (PDR) is a serious ocular disease that can lead to retinal microvascular complications in patients with diabetes mellitus. To date, no studies have explored PDR development by analyzing the aqueous humor (AH). Therefore we carried out tandem mass tag (TMT) proteomic quantification to compare AH protein profiles between PDR and non-PDR subjects.

Methods

We enrolled six PDR and six control (senile cataract) subjects. AH samples were collected during surgery and stored at –80°C. Proteins were extracted, trypsin-digested, and labeled with TMTs for mass spectrometric analysis.

Results

We found 191 proteins to be changed with |log₂ (fold change)| ≥1 (P < 0.05 and identification with at least two peptides per protein). Of them, 111 were downregulated, whereas 80 were upregulated in the PDR group. Proteomic bioinformatic analysis indicated that PDR development was related to complement and coagulation cascades, platelet activation, extracellular matrix–receptor interaction, focal adhesion, protein digestion and absorption, human papillomavirus infection, PI3K-Akt signaling pathway, cholesterol metabolism, peroxisome proliferator-activated receptor signaling pathways, fat digestion and absorption, and vitamin digestion and absorption pathways.

Conclusions

Comprehensive proteomic profiling of the AH revealed 191 differentially expressed proteins between the two groups. Most of these proteins belong to secretory pathways, and therefore can be used as biomarkers in clinical testing and basic research.

Translational Relevance

Pathway analysis and a review of the literature enabled us to draw a novel biological map that will support further studies on the underlying mechanisms and therapeutic control of PDR development.

Atorvastatin-Eluting Contact Lenses: Effects of Molecular Imprinting and Sterilization on Drug Loading and Release

Statins are receiving increasing attention in the ophthalmic field. Their activity as 3-hydroxy-3-methylglutaryl–CoA (HMG–CoA) reductase inhibitors is clinically used to regulate cholesterol levels and leads to pleiotropic effects, which may help in the management of diabetes-related ocular pathologies. This work aims to design bioinspired contact lenses (CLs) with an affinity for atorvastatin by mimicking the active site of HMG–CoA reductase. Sets of imprinted and nonimprinted 2-hydroxyethyl methacrylate (HEMA) hydrogels were synthesized, varying the contents in functional monomers that bear chemical groups that resemble those present in HMG–CoA reductase, namely, ethylene glycol phenyl ether methacrylate (EGPEM), 2-aminoethyl methacrylate hydrochloride (AEMA), and N-(3-aminopropyl) methacrylamide hydrochloride (APMA). The hydrogels were characterized in terms of suitability as CLs (solvent uptake, light transmission, mechanical properties, and biocompatibility) and capability to load and release atorvastatin. Three sterilization protocols (steam heat, gamma radiation, and high hydrostatic pressure) were implemented and their effects on hydrogel properties were evaluated. Copolymerization of AEMA and, particularly, APMA endowed the hydrogels with a high affinity for atorvastatin (up to 11 mg/g; K_N/W > 200). Only high hydrostatic pressure sterilization preserved atorvastatin stability and hydrogel performance. Permeability studies through the porcine cornea and sclera tissues revealed that the amount of atorvastatin accumulated in the cornea and sclera could be effective to treat ocular surface diseases.

Systemic diseases and the cornea

There is a number of systemic diseases affecting the cornea. These include endocrine disorders (diabetes, Graves' disease, Addison's disease, hyperparathyroidism), infections with viruses (SARS-CoV-2, herpes simplex, varicella zoster, HTLV-1, Epstein-Barr virus) and bacteria (tuberculosis, syphilis and Pseudomonas aeruginosa), autoimmune and inflammatory diseases (rheumatoid arthritis, Sjögren's syndrome, lupus erythematosus, gout, atopic and vernal keratoconjunctivitis, multiple sclerosis, granulomatosis with polyangiitis, sarcoidosis, Cogan's syndrome, immunobullous diseases), corneal deposit disorders (Wilson's disease, cystinosis, Fabry disease, Meretoja's syndrome, mucopolysaccharidosis, hyperlipoproteinemia), and genetic disorders (aniridia, Ehlers-Danlos syndromes, Marfan syndrome). Corneal manifestations often provide an insight to underlying systemic diseases and can act as the first indicator of an undiagnosed systemic condition. Routine eye exams can bring attention to potentially life-threatening illnesses. In this review, we provide a fairly detailed overview of the pathologic changes in the cornea described in various systemic diseases and also discuss underlying molecular mechanisms, as well as current and emerging treatments.

Optical Coherence Tomography Angiography in Diabetes and Diabetic Retinopathy

Diabetic retinopathy (DR) is a common complication of diabetes mellitus that disrupts the retinal microvasculature and is a leading cause of vision loss globally. Recently, optical coherence tomography angiography (OCTA) has been developed to image the retinal microvasculature, by generating 3-dimensional images based on the motion contrast of circulating blood cells. OCTA offers numerous benefits over traditional fluorescein angiography in visualizing the retinal vasculature in that it is non-invasive and safer; while its depth-resolved ability makes it possible to visualize the finer capillaries of the retinal capillary plexuses and choriocapillaris. High-quality OCTA images have also enabled the visualization of features associated with DR, including microaneurysms and neovascularization and the quantification of alterations in retinal capillary and choriocapillaris, thereby suggesting a promising role for OCTA as an objective technology for accurate DR classification. Of interest is the potential of OCTA to examine the effect of DR on individual retinal layers, and to detect DR even before it is clinically detectable on fundus examination. We will focus the review on the clinical applicability of OCTA derived quantitative metrics that appear to be clinically relevant to the diagnosis, classification, and management of patients with diabetes or DR. Future studies with longitudinal design of multiethnic multicenter populations, as well as the inclusion of pertinent systemic information that may affect vascular changes, will improve our understanding on the benefit of OCTA biomarkers in the detection and progression of DR.

Knowledge, awareness and perceptions of diabetes mellitus among the Saudi population

Background: High prevalence of undiagnosed cases of diabetes mellitus (DM) has increased over the last two decades, most patients with DM only become aware of their condition once they develop a complication. Limited data are available regarding the knowledge and awareness about DM and the associated risk factors, complications and management in Saudi society. Aim: This study aimed to assess knowledge of DM in general Saudi society and among Saudi healthcare workers. Results: Only 37.3% of the participants were aware of the current DM prevalence. Obesity was the most frequently identified risk factor for DM. Most comparisons indicated better awareness among health workers. Conclusion: A significant lack of knowledge about DM in Saudi society was identified. Social media and educational curriculum can improve knowledge and awareness of DM.

Gender-related differences in patients treated with intravitreal anti-vascular endothelial growth factor medication for diabetic macular oedema

BACKGROUND

Diabetes prevalence is constantly rising, involving the eyes with damage including development of diabetic macular oedema. Since 2012, intravitreal anti-vascular endothelial growth factor medication is available for diabetic macular oedema treatment. Endocrinological studies have shown that fewer women are affected by diabetes. However, when affected, they exhibit more severe diabetic complications than men. We have investigated gender-related differences in diabetic macular oedema and outcome in an ophthalmological tertiary referral hospital.

METHODS

We included 88 patients (54 males and 34 females) with 112 eyes (68 male and 44 female) having clinically significant diabetic macular oedema, treated with anti-vascular endothelial growth factor medication. A 1 year follow-up was performed in all patients (visual acuity and optical coherence tomography). Previous retinal surgery was an exclusion criterion, as were other retinal pathologies.

RESULTS

The mean visual acuity and mean central retinal thickness at baseline were 0.53 logMAR (male 0.49 and female 0.595) and 469 μm (male 452 μm and female: 494 μm), respectively. After 360 days, mean visual acuity changed by -0.07 (±0.36) logMAR (male -0.11 and female +0.01) and mean central retinal thickness changed by -119 μm (male -113 μm and female -127 μm). For visual acuity, a significant difference was noted at baseline (p = 0.02) and at 1 year (p < 0.001). Males received 5.6 injections and females received 5.68 injections in 1 year.

CONCLUSION

Our study showed that female patients with diabetic macular oedema were diagnosed with and treated for diabetic macular oedema at a stage when visual acuity and optical coherence tomography were worse than those in their male counterparts. This gender difference could not be reduced, despite similar numbers of injections. Female diabetic patients should therefore be assessed early for ophthalmological pathologies.

Diabetic complications in the cornea

Diabetic corneal alterations, such as delayed epithelial wound healing, edema, recurrent erosions, neuropathy/loss of sensitivity, and tear film changes are frequent but underdiagnosed complications of both type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetes mellitus. The disease affects corneal epithelium, corneal nerves, tear film, and to a lesser extent, endothelium, and also conjunctiva. These abnormalities may appear or become exacerbated following trauma, as well as various surgeries including retinal, cataract or refractive. The focus of the review is on mechanisms of diabetic corneal abnormalities, available animal, tissue and organ culture models, and emerging treatments. Changes of basement membrane structure and wound healing rates, the role of various proteinases, advanced glycation end products (AGEs), abnormal growth and motility factors (including opioid, epidermal, and hepatocyte growth factors) are analyzed. Experimental therapeutics under development, including topical naltrexone, insulin, inhibitors of aldose reductase, and AGEs, as well as emerging gene and cell therapies are discussed in detail.

CORRELATION OF INCREASED INTRAVITREOUS WNT3A WITH VASCULAR ENDOTHELIAL GROWTH FACTOR IN PROLIFERATIVE DIABETIC RETINOPATHY

PURPOSE

To investigate Wnt3a and vascular endothelial growth factor (VEGF) levels in the vitreous fluid of patients with proliferative diabetic retinopathy (PDR) and to examine their correlation with PDR activity.

METHODS

Vitreous samples from 45 eyes with PDR and 28 eyes with nondiabetic macular disease were collected. Active PDR was present in 24 patients and inactive PDR in 21 patients, according to retinal neovascularization. The Wnt3a and VEGF level of vitreous fluid samples were measured by enzyme-linked immunosorbent assay.

RESULTS

Comparison revealed that mean intravitreal levels of Wnt3a increased significantly in PDR eyes compared with control eyes (13.55 ng/mL vs. 1.57 ng/mL, P < 0.001). The mean VEGF concentrations in the vitreous fluid of patients with PDR were also higher than those in nondiabetic controls, with the values being 723.21 pg/mL and 20.81 pg/mL, respectively (P < 0.001). In addition, vitreous concentrations of Wnt3a and VEGF were significantly higher in active PDR than in eyes with inactive PDR (P = 0.016 and P = 0.008, respectively). Furthermore, a significant positive correlation was detected between Wnt3a and VEGF levels in the vitreous.

CONCLUSION

Intravitreous levels of Wnt3a and VEGF in patients with PDR are increased and correlated mutually. Wnt3a may be an important player in the development of diabetic retinopathy and its activity in vitreous fluid can be biomarker of PDR.

Association of serum and vitreous concentrations of osteoprotegerin with diabetic retinopathy

BACKGROUND

Angiogenesis is involved in the pathogenesis of diabetic retinopathy. Osteoprotegerin, a recently identified glycoprotein belonging to the tumour necrosis factor receptor superfamily, has been implicated to be correlated with angiogenesis. This study aims to determine whether serum and vitreous concentrations of osteoprotegerin are associated with diabetic retinopathy.

METHODS

This study consisted of 254 diabetic patients (100 without diabetic retinopathy, 64 with non-proliferative diabetic retinopathy and 90 with proliferative diabetic retinopathy) and 62 control subjects. Serum and vitreous concentrations of osteoprotegerin were evaluated using enzyme-linked immunosorbent assay method.

RESULTS

Serum and vitreous osteoprotegerin concentrations in proliferative diabetic retinopathy patients were significantly elevated compared with those of the other three groups. Non-proliferative diabetic retinopathy patients showed elevated concentrations of serum and vitreous osteoprotegerin compared with patients without diabetic retinopathy. In addition, control subjects had significantly lower serum and vitreous osteoprotegerin concentrations compared with diabetic patients without retinopathy, non-proliferative diabetic retinopathy patients and proliferative diabetic retinopathy patients.

CONCLUSIONS

Serum and vitreous osteoprotegerin concentrations are associated with the presence and severity of diabetic retinopathy.

Intraocular expression of serum amyloid a and interleukin-6 in proliferative diabetic retinopathy

PURPOSE

Because serum amyloid A can regulate angiogenesis, we searched for an association between serum amyloid A and interleukin-6 (IL-6), as proinflammatory factors, and proliferative diabetic retinopathy (PDR).

DESIGN

Retrospective, comparative study.

METHODS

Seventy-six patients (76 eyes) with PDR and 31 patients (31 eyes) with nondiabetic ocular disease (control group), including idiopathic epiretinal membranes (8 eyes) and idiopathic macular holes (23 eyes), were enrolled. Enzyme-linked immunosorbent assay, dual-color immunofluorescence staining, and semiquantitative reverse-transcription polymerase chain reaction were used to examine the serum amyloid A and IL-6 levels in vitreous and plasma, expression of protein and mRNA of serum amyloid A in the excised membranes, respectively.

RESULTS

Vitreous serum amyloid A and IL-6 levels in the study group were significantly higher than those in the control group (both P < .001), whereas the plasma concentrations of serum amyloid A and IL-6 did not vary significantly between the groups (P = .555 and P = .621, respectively). A significant correlation was observed between the vitreous and plasma levels of serum amyloid A in subjects with PDR (r = 0.525; P < .001). In fibrovascular membranes of the study group, colocalization of endothelial marker CD31 with serum amyloid A and colocalization of fibrillar structure markers fibronectin with serum amyloid A were observed. Expression of serum amyloid A mRNA was significantly higher in fibrovascular membranes with PDR than in idiopathic epiretinal membranes (P = .004).

CONCLUSIONS

Serum amyloid A and IL-6 may be involved with the inflammatory process in the development of PDR. Local expression of serum amyloid A may exist in PDR.

The role of vitamin E and oxidative stress in diabetes complications

Diabetes is a disease characterized by poor glycemic control for which risk of the type 2 form increases with age. A rise in blood glucose concentration causes increased oxidative stress which contributes to the development and progression of diabetes-associated complications. Studies have shown that primary antioxidants or genetic manipulation of antioxidant defenses can at least partially ameliorate this oxidative stress and consequentially, reduce severity of diabetic complications in animal models. Data from humans is less clear and will be summarized in this review. We highlight results from studies performed to investigate the role of vitamin E in preventing diabetes-induced oxidative damage in cell culture, animal models, and human participants, and summarize evidence testing whether this nutrient has an effect on outcomes related to the diabetic complications of nephropathy, retinopathy, and neuropathy. The most compelling evidence for an effect of vitamin E in diabetes is on protection against lipid peroxidation, whereas effects on protein and DNA oxidation are less pronounced. More studies are required to make definitive conclusions about the effect of vitamin E treatment on diabetes complications in human subjects.