The Vitreomacular Interface in Diabetic Retinopathy

Liquid Biopsy for Proliferative Diabetic Retinopathy: Single-Cell Transcriptomics of Human Vitreous Reveals Inflammatory T-Cell Signature

Purpose

Current therapies for proliferative diabetic retinopathy (PDR) do not specifically target VEGF-independent, cell-type-specific processes that lead to vision loss, such as inflammatory pathways. This study aimed to identify targetable cell types and corresponding signaling pathways by elucidating the single-cell landscape of the vitreous of patients with PDR.

Design

Case series.

Subjects

Vitreous and peripheral blood obtained from 5 adult patients (6 eyes) undergoing pars plana vitrectomy for vision-threatening PDR.

Methods

Single-cell RNA sequencing (scRNA-seq) was performed on vitreous cells obtained from diluted cassette washings during vitrectomy from 6 eyes and peripheral blood mononuclear cells (PBMCs, n = 5). Droplet-based scRNA-seq was performed using the Chromium 10x platform to obtain single-cell transcriptomes. Differences in tissue compartments were analyzed with gene ontology enrichment of differentially expressed genes and an unbiased ligand-receptor interaction analysis.

Main Outcome Measures

Single-cell transcriptomic profiles of vitreous and peripheral blood.

Results

Transcriptomes from 13 675 surgically harvested vitreous cells and 22 636 PBMCs were included. Clustering revealed 4 cell states consistently across all eyes with representative transcripts for T cells (CD2, CD3D, CD3E, and GZMA), B cells (CD79A, IGHM, MS4A1 (CD20), and HLA-DRA), myeloid cells (LYZ, CST3, AIF1, and IFI30), and neutrophils (BASP1, CXCR2, S100A8, and S100A9). Most vitreous cells were T cells (91.6%), unlike the peripheral blood (46.2%), whereas neutrophils in the vitreous were essentially absent. The full repertoire of adaptive T cells including CD4+, CD8+ and T regulatory cells (Treg) and innate immune system effectors (i.e., natural killer T cells) was present in the vitreous. Pathway analysis also demonstrated activation of CD4+ and CD8+ memory T cells and ligand-receptor interactions unique to the vitreous.

Conclusions

In the first single-cell transcriptomic characterization of human vitreous in a disease state, we show PDR vitreous is primarily composed of T cells, a critical component of adaptive immunity, with activity and proportions distinct from T cells within the peripheral blood, and neutrophils are essentially absent. These results demonstrate the feasibility of liquid vitreous biopsies via collection of otherwise discarded, diluted cassette washings during vitrectomy to gain mechanistic and therapeutic insights into human vitreoretinal disease.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Evaluation of the effect of vitreomacular interface disorders on anti-VEGF treatment in patients with diabetic macular edema in real life: MARMASIA study group report No. 10

PURPOSE

The aim of this study is to investigate the effect of vitreomacular interface disorders (VMID) on treatment response in patients treated with anti-vascular endothelial growth factor (anti-VEGF) due to diabetic macular edema (DME).

METHODS

Three hundred seventy-seven eyes of 239 patients in the MARMASIA Study Group who received intravitreal anti-VEGF treatment (IVT) due to DME were included in the study. The group 1 consisted of 44 eyes of the patients who had not received any treatment before, were followed up regularly for 24 months after at least a 3-month loading dose, and suffered from VMID such as epiretinal membrane, vitreomacular adhesion or traction, and lamellar hole. The group 2 consisted of 333 eyes of the patients without VMID. Best-corrected visual acuity (BCVA) and central macular thickness (CMT) of the patients at baseline, 3rd month, 6th month, 1st year and 2nd year follow-ups were measured.

RESULTS

The mean age of the Groups 1 and 2 was 67.1 ± 11.3 and 61.9 ± 10.2 years, respectively. 61.3% of the group 1 and 58.8% of the group 2 were female (p > 0.05). The duration of diabetes was 19.2 ± 3.7 and 15.8 ± 3.2 years, respectively, and the number of follow-ups was 16.09 ± 4.68 and 12.06 ± 4.58, respectively in the groups (p < 0.001, 0.001, respectively). The number of IVT was 7.13 ± 2.71 and 7.20 ± 2.22, respectively in the groups 1 and 2 and no statistically significant difference was observed between them (p = 0.860). According to logMAR, BCVA values at baseline were 0.63 ± 0.24 and 0.59 ± 0.26 (p = 0.29), respectively, in the groups and the amount of change in BCVA at the end of the 2nd year was - 0.02 ± 0.48 in the group 1 and - 0.12 ± 0.48 in the group 2. It was observed as 0.48 (p = 0.13). Although the increase in BCVA was greater at all follow-ups in the group 2 compared to their initial examination, no significant difference was observed between the groups in terms of BCVA change. The CMT values of the groups at baseline were 442.5 ± 131.3 µm and 590.9 ± 170.6 µm, respectively (p = 0.03) The decrease in CMT after IVT was significantly greater in the group 2 at all follow-ups when compared to the first group (p < 0.05).

CONCLUSION

While the presence of VMID in DME patients receiving IVT did not affect visual results, it negatively affected the anatomical response and macular edema morphology. The presence of VMID at baseline affected the success of IVT. It should be taken into consideration that VMID may resolve spontaneously or with IVT, and new cases of VMID may occur in patients during the treatment process.

Predictors of Diabetic Retinopathy in Type 2 Diabetes: A Cross-Sectional Study

BACKGROUND

Type 2 diabetes mellitus (T2DM) represents one of the most impacting health issues of the modern era, as it is associated with an extensive range of comorbidities. Diabetic retinopathy (DR) is one the utmost severe diabetes complications as it is one of the major causes of vision loss among these patients. Our present research aims to evaluate the most frequent risk factors related to the occurrence of DR in T2DM patients.

METHOD

This study consisted of a research group of 302 participants, priorly diagnosed with T2DM, that were evaluated for the most important risk factors related to the occurrence of DR.

RESULTS

Patients had a median age of 64 years, 48% of them being women, with a 12-year median duration of DM and presenting a deficient glycaemic control echoed by a median HbA1C value of 7.5%. From the total number of participants, the total prevalence of DR in different stages of severity was 34.8% with a 95% CI. Statistically significant values were found regarding DM duration (p = 0.007), HbA1c > 7.2% (p = 0.001) and patients aged over 67 years (p = 0.0035), all these parameters being directly linked to DR.

CONCLUSIONS

Older patients with T2DM that have a longer disease duration and simultaneous comorbidities present a higher risk of DR development, consequently a stringent management of these pathologies is needed.

Colorimetric Analyses of the Optic Nerve Head and Retina Indicate Increased Blood Flow After Vitrectomy

Purpose

The purpose of this study was to evaluate the impact of vitrectomy and posterior hyaloid (PH) peeling on color alteration of optic nerve head (ONH) and retina as a surrogate biomarker of induced perfusion changes.

Methods

Masked morphometric and colorimetric analyses were conducted on preoperative (<1 month) and postoperative (<18 months) color fundus photographs of 54 patients undergoing vitrectomy, either with (44) or without (10) PH peeling and 31 years of age and gender-matched control eyes. Images were calibrated according to the hue and saturation values of the parapapillary venous blood column. Chromatic spectra of the retinal pigment epithelium and choroid were subtracted to avoid color aberrations. Red, green, and blue (RGB) bit values over the ONH and retina were plotted within the constructed RGB color space to analyze vitrectomy-induced color shift. Vitrectomy-induced parapapillary vein caliber changes were also computed morphometrically.

Results

A significant post-vitrectomy red hue shift was noted on the ONH (37.1 degrees ± 10.9 degrees vs. 4.1 degrees ± 17.7 degrees, P < 0.001), which indicates a 2.8-fold increase in blood perfusion compared to control (2.6 ± 1.9 vs. 0.9 ± 1.8, P < 0.001). A significant post-vitrectomy increase in the retinal vein diameter was also noticed (6.8 ± 6.4% vs. 0.1 ± 0.3%, P < 0.001), which was more pronounced with PH peeling (7.9 ± 6.6% vs. 3.1 ± 4.2%, P = 0.002).

Conclusions

Vitrectomy and PH peeling increase ONH and retinal blood flow. Colorimetric and morphometric analyses offer valuable insights for future artificial intelligence and deep learning applications in this field.

Translational Relevance

The methodology described herein can easily be applied in different clinical settings and may enlighten the beneficial effects of vitrectomy in several retinal vascular diseases.

The additive effect of intravitreal dexamethasone combined with bevacizumab in refractory diabetic macular edema

PURPOSE

To evaluate the short-term structural and visual outcomes and side effects associated with intravitreal dexamethasone (IVD) combined with bevacizumab (IVB) in treating patients with diabetic macular edema (DME) and an inadequate response to anti-vascular endothelial growth factor (anti-VEGF) agents.

METHODS

In this prospective interventional case series, a total of 81 eyes of 81 patients with type 2 diabetes mellitus (T2DM) and refractory DME were included and assigned to one of two groups: I) those receiving three monthly intravitreal injections of combined bevacizumab and dexamethasone (IVB+IVD) and II) those receiving three monthly intravitreal injections of bevacizumab alone (IVB). The primary outcome was the inter-group difference in central macular thickness (CMT); secondary outcomes included best-corrected visual acuity (BCVA), baseline optical coherence tomography (OCT) biomarkers, and intraocular pressure (IOP) one month after the last injection.

RESULTS

Reduction in CMT and improvement in BCVA were significantly greater in the IVB+IVD group than the IVB group (109.88±156.25 vs. 43±113.67, respectively, P=0.03; and -0.13±0.23 vs. -0.01±0.17, respectively, P=0.008). Presence of neurosensory retinal detachment (NSD) (P<0.001) and complete inner segment/outer segment junction (IS-OS) disruption (P=0.049) on baseline OCT scans were associated with further CMT reductions in response to IVD. Conversely, identifiable epiretinal membrane (ERM) (P=0.002) and multiple hyperreflective foci (>20) (P=0.049) were associated with smaller reductions in CMT. Vitreomacular traction correlated with worse visual outcomes in the IVB+IVD group (P=0.003). The intergroup IOP difference was not clinically significant.

CONCLUSION

In patients with refractory DME, addition of IVD to the standard IVB regimen can improve visual and structural outcomes without increasing the risk of endophthalmitis, IOP rise, or intraocular inflammation. Patients with NSD are more likely to respond well to IVD. The presence of ERM may predict poor treatment response.

Hyalocytes in proliferative vitreo-retinal diseases

Introduction

Hyalocytes are sentinel macrophages residing within the posterior vitreous cortex anterior to the retinal inner limiting membrane (ILM). Following anomalous PVD and vitreoschisis, hyalocytes contribute to paucicellular (vitreo-macular traction syndrome, macular holes) and hypercellular (macular pucker, proliferative vitreo-retinopathy, proliferative diabetic vitreo-retinopathy) diseases.

Areas covered

Studies of human tissues employing dark-field, phase, and electron microscopy; immunohistochemistry; and in vivo imaging of human hyalocytes.

Expert opinion

Hyalocytes are important in early pathophysiology, stimulating cell migration and proliferation, as well as subsequent membrane contraction and vitreo-retinal traction. Targeting hyalocytes early could mitigate advanced disease. Ultimately, eliminating the role of vitreous and hyalocytes may prevent proliferative vitreo-retinal diseases entirely.

NATURAL COURSE OF VITREOMACULAR TRACTION IN EYES WITH DIABETIC RETINOPATHY AND FACTORS ASSOCIATED WITH SPONTANEOUS RELEASE

PURPOSE

The aim of this study was to determine the natural course of vitreomacular traction (VMT) in patients with diabetic retinopathy and to evaluate the factors associated with VMT relief.

METHODS

Seventy-four eyes of 65 patients with VMT accompanying diabetic retinopathy were evaluated retrospectively. The presence of intravitreal injection and the presence of panretinal photocoagulation were obtained from the medical records of the patients. Spontaneous release of VMT, the horizontal length of vitreomacular traction, the presence of hyperreflective retinal spots, the presence of the epiretinal membrane, and the grade of VMT were evaluated from the spectral-domain optical coherence tomography images. Factors associated with the spontaneous release of VMT were evaluated by logistic regression analysis.

RESULTS

Spontaneous release was observed in 28 eyes (37.8%). The horizontal length of VMT was lower in the release of the VMT group compared with the persistent VMT group (P = 0.03). The persistent VMT group had a higher rate of hyperreflective retinal spots and epiretinal membrane compared with the release of the VMT group (respectively; P = 0.003 and P = 0.031). No statistically significant difference was observed between the release of VMT and persistent VMT groups in terms of intravitreal injection and panretinal photocoagulation treatment (respectively; P = 0.938 and P = 0.36). The absence of hyperreflective retinal spots was the most important prognostic factor for the spontaneous release of VMT (P = 0.029).

CONCLUSION

Spontaneous release of VMT observed higher rates of patients without hyperreflective retinal spots, epiretinal membrane, and patients with lower horizontal length of VMT.

Why Miss the Chance? Incidental Findings while Telescreening for Diabetic Retinopathy

PURPOSE

To report on incidental pathological findings met while screening for Diabetic Retinopathy (DR) in Diabetes Clinics (DC) by ophthalmologist-graded digital fundus imaging.

METHODS

At the DC of Pescara (central Italy), for 3,859 eyes of 1,930 consecutive patients having not undergone fundus examination in the last year, two mydriatic fundus digital images, taken with a CenterVue DRS Digital Retinal Camera, were sent along with Best Corrected Visual Acuity, on a "store-and-forward" basis, to an ophthalmologist trained in DR screening, and graded according to the UK Diabetic Eye Screening Programme. Incidental fundus abnormalities other than DR were reported.

RESULTS

No adverse event to mydriasis was reported. One hundred and eighty eyes (4.66%) were ungradable. Among the 3,679 gradable ones, 1,105 (30.04%) showed different degrees of DR (R1 to R3), and 126 (3.42%) maculopathy (M1). Any Age-Related Macular Degeneration was present in 387 eyes (10.52%), any optic disc and parapapillary area features suspect for glaucoma in 562 eyes (15.27%), any hypertensive retinopathy in 1,263 eyes (34.33%), vitreoretinal interface disease in 252 eyes (6.84%), myopic choroidopathy in 92 eyes (2.50%), disc pallor in 31 eyes (0.84%). Mean time was 5 min for screening, 2 min for grading.

CONCLUSION

Teleretinography is a well-established, cost-effective procedure in DR screening. Along with increased attendance, locating a digital camera in a DC with a retina-specialist grader results in finding fundus pathologies also beyond DR, very similarly to fundus examination in an outpatient ophthalmic setting.

Complete Posterior Vitreous Detachment Reduces the Need for Treatment of Diabetic Macular Edema

BACKGROUND AND OBJECTIVE

To evaluate the vitreomacular interface and its relation to treatment burden for diabetic macular edema (DME) in patients without overt vitreomacular traction (VMT).

PATIENTS AND METHODS

A retrospective cohort study of 494 eyes from 274 patients who had macular spectral-domain optical coherence tomography (SD-OCT) and did not have proliferative diabetic retinopathy, DME, or VMT at the initial visit. Posterior vitreous detachment (PVD) was categorized at the initial visit into five stages (0-4) using SD-OCT parameters alone.

RESULTS

Two of 34 eyes (6.9%) presenting with a complete PVD required DME treatment during follow-up, whereas 144 of 460 eyes (31.3%) without a complete PVD at baseline required treatment (P = .001, Chi-squared). After adjusting for age, ethnicity, gender, and HbA1c, complete PVD at baseline was associated with a significant reduction in risk of DME therapy (hazard ratio: 0.18; 95% confidence interval, 0.05-0.73; P = .02).

CONCLUSION

Complete PVD is independently associated with a reduced need for DME treatment. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e266-e273.].

Diabetes and Phacoemulsification Cataract Surgery: Difficulties, Risks and Potential Complications

Diabetes mellitus is one of the most prevalent chronic diseases worldwide. Diabetic patients are at risk of developing cataract and present for surgery at an earlier age than non-diabetics. The aim of this study was to review the problems associated with cataract surgery in a diabetic patient. Corneal complications in diabetic patients include delayed wound healing, risk of developing epithelial defects or recurrent erosions due to the impairment of epithelial basement membranes and epithelial-stromal interactions. Diabetic patients present lower endothelial cell density and their endothelium is more susceptible to trauma associated with cataract surgery. A small pupil is common in diabetic patients making cataract surgery technically challenging. Finally diabetic patients have an increased risk for developing postoperative pseudophakic cystoid macular edema, posterior capsule opacification or endophthalmitis. In patients with pre-proliferative or proliferative diabetic retinopathy, diabetic macular edema or iris neovascularization adjunctive therapy such as an intravitreal anti-vascular endothelial growth factor injection, can inhibit exacerbation related to cataract surgery.

Human vitreous in proliferative diabetic retinopathy: Characterization and translational implications

Diabetic retinopathy (DR) is one of the leading causes of visual impairment in the working-age population. DR is a progressive eye disease caused by long-term accumulation of hyperglycaemia-mediated pathological alterations in the retina of diabetic patients. DR begins with asymptomatic retinal abnormalities and may progress to advanced-stage proliferative diabetic retinopathy (PDR), characterized by neovascularization or preretinal/vitreous haemorrhages. The vitreous, a transparent gel that fills the posterior cavity of the eye, plays a vital role in maintaining ocular function. Structural and molecular alterations of the vitreous, observed during DR progression, are consequences of metabolic and functional modifications of the retinal tissue. Thus, vitreal alterations reflect the pathological events occurring at the vitreoretinal interface. These events are caused by hypoxic, oxidative, inflammatory, neurodegenerative, and leukostatic conditions that occur during diabetes. Conversely, PDR vitreous can exert pathological effects on the diabetic retina, resulting in activation of a vicious cycle that contributes to disease progression. In this review, we recapitulate the major pathological features of DR/PDR, and focus on the structural and molecular changes that characterize the vitreal structure and composition during DR and progression to PDR. In PDR, vitreous represents a reservoir of pathological signalling molecules. Therefore, in this review we discuss how studying the biological activity of the vitreous in different in vitro, ex vivo, and in vivo experimental models can provide insights into the pathogenesis of PDR. In addition, the vitreous from PDR patients can represent a novel tool to obtain preclinical experimental evidences for the development and characterization of new therapeutic drug candidates for PDR therapy.

ILM peeling in nontractional diabetic macular edema: review and metanalysis

PURPOSE

To evaluate the effect of internal limiting membrane (ILM) peeling during vitrectomy for nontractional diabetic macular edema.

METHODS

PUBMED, MEDLINE and CENTRAL were reviewed using the following terms (or combination of terms): diabetic macular edema, nontractional diabetic macular edema, internal limiting membrane peeling, vitrectomy, Müller cells. Randomized and nonrandomized studies were included. The eligible studies compared anatomical and functional outcomes of vitrectomy with or without ILM peeling for tractional and nontractional diabetic macular edema. Postoperative best-corrected visual acuity and central macular thickness were considered, respectively, the primary and secondary outcomes. Meta-analysis on mean differences between vitrectomy with and without ILM peeling was performed using inverse variance method in random effects.

RESULTS

Four studies with 672 patients were eligible for analysis. No significant difference was found between postoperative best-corrected visual acuity or best-corrected visual acuity change of ILM peeling group compared with nonpeeling group. There was no significant difference in postoperative central macular thickness and central macular thickness reduction between the two groups.

CONCLUSIONS

The visual acuity outcomes in patients affected by nontractional diabetic macular edema using pars plana vitrectomy with ILM peeling versus no ILM peeling were not significantly different. A larger prospective and randomized study would be necessary.