The diagnostic function of OCT in diabetic maculopathy. Mediators Inflamm. 2013;2013:434560. [PMID: 24369444 PMCID: PMC3863575 DOI: 10.1155/2013/434560]

Artificial intelligence in retinal screening using OCT images: A review of the last decade (2013-2023)

BACKGROUND AND OBJECTIVES

Optical coherence tomography (OCT) has ushered in a transformative era in the domain of ophthalmology, offering non-invasive imaging with high resolution for ocular disease detection. OCT, which is frequently used in diagnosing fundamental ocular pathologies, such as glaucoma and age-related macular degeneration (AMD), plays an important role in the widespread adoption of this technology. Apart from glaucoma and AMD, we will also investigate pertinent pathologies, such as epiretinal membrane (ERM), macular hole (MH), macular dystrophy (MD), vitreomacular traction (VMT), diabetic maculopathy (DMP), cystoid macular edema (CME), central serous chorioretinopathy (CSC), diabetic macular edema (DME), diabetic retinopathy (DR), drusen, glaucomatous optic neuropathy (GON), neovascular AMD (nAMD), myopia macular degeneration (MMD) and choroidal neovascularization (CNV) diseases. This comprehensive review examines the role that OCT-derived images play in detecting, characterizing, and monitoring eye diseases.

METHOD

The 2020 PRISMA guideline was used to structure a systematic review of research on various eye conditions using machine learning (ML) or deep learning (DL) techniques. A thorough search across IEEE, PubMed, Web of Science, and Scopus databases yielded 1787 publications, of which 1136 remained after removing duplicates. Subsequent exclusion of conference papers, review papers, and non-open-access articles reduced the selection to 511 articles. Further scrutiny led to the exclusion of 435 more articles due to lower-quality indexing or irrelevance, resulting in 76 journal articles for the review.

RESULTS

During our investigation, we found that a major challenge for ML-based decision support is the abundance of features and the determination of their significance. In contrast, DL-based decision support is characterized by a plug-and-play nature rather than relying on a trial-and-error approach. Furthermore, we observed that pre-trained networks are practical and especially useful when working on complex images such as OCT. Consequently, pre-trained deep networks were frequently utilized for classification tasks. Currently, medical decision support aims to reduce the workload of ophthalmologists and retina specialists during routine tasks. In the future, it might be possible to create continuous learning systems that can predict ocular pathologies by identifying subtle changes in OCT images.

Impact of COVID-19-related lifestyle changes on diabetic macular edema

AIM

To assess diabetic macular edema (DME) progression during the early phases of the COVID-19 pandemic, when severe societal restrictions raised the concern of possible deterioration of health in patients with systemic conditions, particularly those requiring frequent office visits.

METHODS

This is a multicenter retrospective chart review of 370 patients (724 eyes) with an established diagnosis of DME seen on 3 separate visits between January 2019 and July 2021. Period 1 was January 2019 to February 2020 (considered pre-COVID-19), period 2 was March 2020 to December 2020 (considered the height of the pandemic; highest level of pandemic-related clinical and societal regulations) and period 3 was January 2021 to July 2021 (re-adjustment to the new "pandemic norms"). Main outcome measures included visual acuity, body mass index (BMI), blood pressure (BP), hemoglobin A1c (HbA1c), macular thickness, patient adherence to scheduled ophthalmology visits, and DME treatment(s) received at each visit. To facilitate measurement of macular thickness, each macula was divided into 9 Early Treatment Diabetic Retinopathy Study (ETDRS)-defined macular sectors as measured by OCT imaging.

RESULTS

There was no change of BMI, systolic BP, and diastolic BP between any of the time periods. HbA1c showed a very small increase from period 1 (7.6%) to period 2 (7.8%, P=0.015) and decreased back to 7.6% at period 3 (P=0.12). Macular thickness decreased for 100% of macular regions. The central macular thickness decreased across all 3 periods from 329.5 to 316.6 µm (P=0.0045). After analysis of multiple variables including HbA1c, BMI, adherence to scheduled appointments, different clinic centers, and treatment interventions, there was no easily identifiable subgroup of patients that experienced the increase in DME.

CONCLUSION

DME doesn't worsen during the COVID-19 pandemic, instead sustaining a very small but statistically significant improvement. While identifying a mechanism behind our findings is beyond the scope of this study, potential explanations may include a delay in retinal changes beyond our study period, an unexpected increase in treatment frequency despite pandemic restrictions, and an unanticipated pandemic-related improvement in some lifestyle factors that may have had a positive impact on DME.

Methylomic, proteomic, and metabolomic correlates of traffic-related air pollution: A systematic review, pathway analysis, and network analysis relating traffic-related air pollution to subclinical and clinical cardiorespiratory outcomes

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease, and highlight contemporary challenges and opportunities associated with such efforts.

Frequency-aware optical coherence tomography image super-resolution via conditional generative adversarial neural network

Optical coherence tomography (OCT) has stimulated a wide range of medical image-based diagnosis and treatment in fields such as cardiology and ophthalmology. Such applications can be further facilitated by deep learning-based super-resolution technology, which improves the capability of resolving morphological structures. However, existing deep learning-based method only focuses on spatial distribution and disregards frequency fidelity in image reconstruction, leading to a frequency bias. To overcome this limitation, we propose a frequency-aware super-resolution framework that integrates three critical frequency-based modules (i.e., frequency transformation, frequency skip connection, and frequency alignment) and frequency-based loss function into a conditional generative adversarial network (cGAN). We conducted a large-scale quantitative study from an existing coronary OCT dataset to demonstrate the superiority of our proposed framework over existing deep learning frameworks. In addition, we confirmed the generalizability of our framework by applying it to fish corneal images and rat retinal images, demonstrating its capability to super-resolve morphological details in eye imaging.

Ocular complications of diabetes mellitus in a pediatric population and proposals for screening and follow-up programs

Background

Diabetes mellitus (DM) is one of the world's greatest health emergencies of the 21st century. Ocular complications of DM are commonly chronic and progressive, but vision loss can be effectively prevented or delayed with early detection and timely treatment. Therefore, regular comprehensive ophthalmologic examinations are mandatory. Ophthalmic screening and dedicated follow-up for adults with DM are well established, whereas, there is no consensus on optimal recommendations for the pediatric population, reflecting the lack of clarity about the current burden of disease in this age group.

Objectives

To determine the epidemiology of ocular complications of diabetes and to assess optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) macular features in a pediatric population with DM. To review ophthalmological screening and follow-up plans for the diabetic pediatric population.

Design

Observational study.

Methods

Retrospective consecutive cohort study of all 165 diabetic patients (330 eyes) aged 0-18 years, examined between January 2006 and September 2018 at the Pediatric Department of 'S. Maria della Misericordia' Udine Hospital who underwent at least one complete ophthalmologic examination at the Ophthalmology University Clinic at the Udine Hospital. OCT and OCTA data were available for 37 patients (72 eyes, 2 excluded). The associations between ocular complications and selected potential risk factors were evaluated by univariate analyses.

Results

No patient had signs of ocular diabetic complications or any macular morphological or micro-vascular impairment, regardless of any potential risk factor. The prevalence of strabismus and refractive errors in the study group, was found to be similar to non-diabetic pediatric populations.

Conclusion

Screening and follow-up of ocular diabetic complications in children and adolescents could be performed less frequently than in adults with diabetes. There is no need to screen potentially treatable visual disorders in diabetic children earlier or more frequently than in the healthy children thus reducing time spent in hospital and permitting a better tolerance to medical examinations in diabetic pediatric patients. We described the OCT and OCTA patterns in a pediatric population with DM.

Study protocol to determine the effects of highly absorbable oral curcumin on the indicators of cognitive functioning: a double-blind randomised controlled trial

INTRODUCTION

Mild cognitive impairment (MCI) refers to a state in which cognitive functions, such as memory, have diminished but daily activities are largely unhampered. MCI is often overlooked but carries the risk of leading to development of dementia later. Curcumin is the main component of the natural herbal medicine turmeric. Curcumin is widely used as a health food and is an antioxidant that has anti-inflammatory and anti-amyloid actions. The current trial was designed to determine the effects of curcumin on indicators of cognitive functioning.

METHODS AND ANALYSIS

The current trial will be a single-centre randomised placebo-controlled double-blind parallel group trial. The participants will be 60 members of the general public with potential MCI, based on dementia screening using the Japanese version of the Mini Mental State Examination (MMSE-J). The investigational health food used in this trial will be a recently developed preparation for highly absorbable oral curcumin. This trial will determine the effects of the highly absorbable oral curcumin (brand name: curcuRouge) on the indicators of cognitive functioning, including the scores obtained with the MMSE-J, which is an interview-based measure of cognitive functioning, and the blood biomarkers that have been reported to be associated with dementia.

ETHICS AND DISSEMINATION

Informed written consent will be obtained from all the participants. The Ethical Review Board of the National Hospital Organization Kyoto Medical Center approved the study protocol.

TRIAL REGISTRATION NUMBER

University Hospital Medical Information Network (UMIN000042471).

Lactobacillus rhamnosus sepsis, endocarditis and septic emboli in a patient with ulcerative colitis taking probiotics

A man in his 60s presented to the emergency room with fever and fatigue after a 2.5-month course of corticosteroids. His medical history was significant for bioprosthetic aortic valve replacement and moderately severe ulcerative colitis treated with balsalazide and daily lactobacillus-containing probiotics. Initial investigations revealed Lactobacillus rhamnosus bacteraemia without complication. Four days after hospital discharge, the patient experienced acute-onset right-sided paraesthesia and lower-limb paresis. On return to the emergency room, MRI of the brain demonstrated innumerable ring-enhancing lesions with haemorrhagic transformation. Transoesophageal echocardiogram revealed a small mobile density on the bioprosthetic aortic valve, raising the suspicion for L. rhamnosus infective endocarditis with secondary septic emboli to the brain. The patient was subsequently treated with intravenous gentamycin and ampicillin, with transition to indefinite oral amoxicillin suppressive therapy. The current case highlights the potential risk of lactobacilli translocation in an immunosuppressed patient with ulcerative colitis taking probiotics.

Effect of anaesthetic depth on primary postoperative ileus after laparoscopic colorectal surgery: protocol for and preliminary data from a prospective, randomised, controlled trial

INTRODUCTION

Primary postoperative ileus is one of the principal factors affecting in-hospital recovery after colorectal surgery. Research on the relationship between anaesthetic depth and perioperative outcomes has been attracting growing attention. However, the impact of anaesthetic depth on the recovery of gastrointestinal function after surgery is unclear. We aimed to conduct a single-centre, prospective, randomised, controlled trial to explore the effect of anaesthetic depth on primary postoperative ileus after laparoscopic colorectal surgery.

METHODS AND ANALYSIS

In this single-centre, prospective, patient-blinded and assessor-blinded, parallel, randomised, controlled trial, a total of 854 American Society of Anesthesiologists physical status I-III patients, aged between 18 and 65 years and scheduled for laparoscopic colorectal surgery lasting ≥2 hours, will be randomly assigned to deep anaesthesia group (Bispectral Index (BIS) 30-40) or light anaesthesia group (BIS 45-55). The primary outcome is primary postoperative ileus during the hospital stay. Secondary outcomes were time to gastrointestinal function recovery, another defined postoperative ileus, 15-item quality of recovery score, length of postoperative stay, postoperative 30-day complications and serum concentrations of intestinal fatty acid-binding protein at 6 hours after surgery.

ETHICS AND DISSEMINATION

The protocol was approved by Medical Ethics Committee of Nanfang Hospital, Southern Medical University (Approval number: NFEC-2018-107) prior to recruitment. All participants will provide written informed consent before randomisation. Findings of the trial will be disseminated through peer-reviewed journals and scientific conferences.

TRIAL REGISTRATION NUMBER

ChiCTR1800018725.

Cell membrane-anchored and tumor-targeted IL-12 (attIL12)-T cell therapy for eliminating large and heterogeneous solid tumors

BACKGROUND

Adoptive T-cell transfer has become an attractive therapeutic approach for hematological malignancies but shows poor activity against large and heterogeneous solid tumors. Interleukin-12 (IL-12) exhibits potent antitumor efficacy against solid tumors, but its clinical application has been stalled because of toxicity. Here, we aimed to develop a safe approach to IL-12 T-cell therapy for eliminating large solid tumors.

METHODS

We generated a cell membrane-anchored IL-12 (aIL12), a tumor-targeted IL-12 (ttIL12), and a cell membrane-anchored and ttIL-12 (attIL12) and a cell membrane-anchored and tumor-targeted ttIL-12 (attIL12) armed T cells, chimeric antigen receptor-T cells, and T cell receptor-T (TCR-T) cells with each. We compared the safety and efficacy of these armed T cells in treating osteosarcoma patient-derived xenograft tumors and mouse melanoma tumors after intravenous infusions of the armed T cells.

RESULTS

attIL12-T cell infusion showed remarkable antitumor efficacy in human and mouse large solid tumor models. Mechanistically, attIL12-T cells targeted tumor cells expressing cell-surface vimentin, enriching effector T cell and interferon γ production in tumors, which in turn stimulates dendritic cell maturation for activating secondary T-cell responses and tumor antigen spreading. Both attIL12- and aIL12-T-cell transfer eliminated peripheral cytokine release and the associated toxic effects.

CONCLUSIONS

This novel approach sheds light on the safe application of IL-12-based T-cell therapy for large and heterogeneous solid tumors.

Early-life famine exposure and rheumatoid arthritis in Chinese adult populations: a retrospective cohort study

OBJECTIVE

This study aimed to explore the association between famine exposure in early life and the odds of rheumatoid arthritis (RA) in adulthood.

DESIGN

A population-based retrospective cohort study.

SETTING

China.

PARTICIPANTS

A total of 111 706 participants (1775 with RA) born from 1956 to 1964 were selected from the baseline survey of a large cohort in China.

PRIMARY AND SECONDARY OUTCOME MEASURES

Four famine exposure groups were generated based on dates of birth, namely prenatal-exposed, infant-exposed, preschool-exposed and non-exposed groups. Logistic regressions were used to explore the association between famine exposure and self-reported RA in adulthood, adjusting for sex, region, monthly income, highest education, alcohol consumption, tobacco use, body mass index (BMI) and metabolic equivalent tasks. Analyses were also performed with stratification for sex (female or male), residing region (urban or rural), famine severity (severe or non-severe) and BMI (≥24 or <24).

RESULTS

The study included 1775 (1.59%) RA cases and 109 931 (98.41%) non-RA controls. Among them, 22 413 (20.06%) were prenatal-exposed, 14 899 (13.34%) were infant-exposed and 34 356 (30.76%) were preschool-exposed. Prenatal exposure to famine was not associated with onset of RA in adulthood. Infant-exposed group and preschool-exposed group had significantly elevated odds of getting RA compared with non-exposed group (infant-exposed: OR=1.44, 95% CI 1.24 to 1.67; preschool-exposed: OR=1.38, 95% CI 1.22 to 1.57, p<0.001), and the relationship was stronger among women, urban residents and participants with BMI ≥24. Similar results were additionally observed when an age-balanced control group was used.

CONCLUSIONS

Exposure to the Great Chinese Famine in early life after birth especially in infancy may be associated with a higher risk of RA in adulthood. Strengthening early-life nutrition could be an implication to prevent future RA.

Effect of resolvins on sensitisation of TRPV1 and visceral hypersensitivity in IBS

OBJECTIVE

Resolvins (RvD1, RvD2 and RvE1) are endogenous anti-inflammatory lipid mediators that display potent analgesic properties in somatic pain by modulating transient receptor potential vanilloid 1 (TRPV1) activation. To what extent these molecules could also have a beneficial effect on TRPV1 sensitisation and visceral hypersensitivity (VHS), mechanisms involved in IBS, remains unknown.

DESIGN

The effect of RvD1, RvD2 and RvE1 on TRPV1 activation and sensitisation by histamine or IBS supernatants was assessed on murine dorsal root ganglion (DRG) neurons using live Ca²⁺ imaging. Based on the results obtained in vitro, we further studied the effect of RvD2 in vivo using a murine model of post-infectious IBS and a rat model of post-inflammatory VHS. Finally, we also tested the effect of RvD2 on submucosal neurons in rectal biopsies of patients with IBS.

RESULTS

RvD1, RvD2 and RvE1 prevented histamine-induced TRPV1 sensitisation in DRG neurons at doses devoid of an analgesic effect. Of note, RvD2 also reversed TRPV1 sensitisation by histamine and IBS supernatant. This effect was blocked by the G protein receptor 18 (GPR18) antagonist O-1918 (3-30 µM) and by pertussis toxin. In addition, RvD2 reduced the capsaicin-induced Ca²⁺ response of rectal submucosal neurons of patients with IBS. Finally, treatment with RvD2 normalised pain responses to colorectal distention in both preclinical models of VHS.

CONCLUSIONS

Our data suggest that RvD2 and GPR18 agonists may represent interesting novel compounds to be further evaluated as treatment for IBS.

Pro-inflammatory cytokine profile is present in the serum of Mexican patients with different stages of diabetic retinopathy secondary to type 2 diabetes

Aim

It’s been reported that pro-inflammatory cytokines are elevated in patients with diabetic retinopathy (DR); this may contribute to the pathophysiology of the disease. The aim of this study is to measure the concentration of various inflammatory cytokines from the main CD4+ T helper inflammatory responses in blood serum from Mexican patients with DR in different stages using cytometric bead array (CBA) technology and correlate them with the presence and severity of DR in order to find possible DR biomarkers that serve as diagnostic or therapeutic predictors.

Methods

64 subjects were included in the study, 16 in the control group, 16 in the type 2 diabetes mellitus no DR (NDR) group, 16 in the non-proliferative DR (NPDR) group and 16 in the proliferative DR (PDR) group. Cytokine concentrations of interleukin (IL) 1ß, IL‐2, IL‐4, IL‐6, IL‐8, IL‐10, IL‐12, IL‐17A, tumour necrosis factor alpha (TNFα) and interferon-gamma in serum samples were measured using Human Inflammatory and TH1/TH2/TH17 CBA Kit.

Results

IL-6, IL-12, IL-17a and TNFα were significantly higher in the patients with DR compared with the control group. The PDR group showed a slightly lower concentration of serum cytokines IL-6, IL-12 and IL-17a. TNFα showed a higher concentration compared with healthy controls, NDR and NPDR subjects. We also found a positive statistical correlation between the presence and severity of DR with the clinical parameters haemoglobin A1c, body mass index and serum creatinine and the concentration of serum cytokines IL-6 and TNFα.

Conclusion

Our findings suggest that patients with diabetes and DR have a stronger chronic inflammatory profile compared with non-diabetic subjects.

Oxidized LDL, insulin sensitivity and beta-cell function in newborns

INTRODUCTION

Oxidized low-density lipoprotein (OxLDL), a biomarker of oxidative stress, itself possesses proatherogenic and proinflammatory effects. Elevated circulating OxLDL levels have been consistently associated with insulin resistance and diabetes in adults. We sought to assess whether OxLDL may be associated with insulin sensitivity and beta-cell function in early life.

RESEARCH DESIGN AND METHODS

In a birth cohort study, we assessed cord plasma OxLDL concentration and OxLDL to total LDL ratio in relation to glucose to insulin ratio (an indicator of fetal insulin sensitivity), proinsulin to insulin ratio (an indicator of fetal beta-cell function), and leptin and adiponectin concentrations in 248 singleton newborns.

RESULTS

Cord plasma OxLDL concentration was positively correlated with glucose to insulin ratio (r=0.24, p<0.001) and proinsulin to insulin ratio (r=0.20, p<0.001) and was not correlated with leptin or adiponectin. Adjusting for maternal and neonatal characteristics, each log unit increase in cord plasma OxLDL concentration was associated with a 25.8% (95% CI 12.8% to 40.3%) increase in glucose to insulin ratio and a 19.0% (95% CI 6.8% to 32.9%) increase in proinsulin to insulin ratio, respectively. Similar associations were observed for cord plasma OxLDL to LDL ratio in relation to cord plasma glucose to insulin ratio and proinsulin to insulin ratio.

CONCLUSIONS

Higher OxLDL levels were associated with lower fetal beta-cell function (higher proinsulin to insulin ratio) but higher insulin sensitivity (higher glucose to insulin ratio). The study is the first to demonstrate that OxLDL may affect glucose metabolic health in early life in humans.

Saudi Arabia Guidelines for diabetic macular edema: A consensus of the Saudi Retina Group

Diabetes mellitus (DM) and its complications are major public health burdens in Saudi Arabia. The prevalence of diabetic retinopathy (DR) is 19.7% and the prevalence of diabetic macular edema (DME) is 5.7% in Saudi Arabia. Diabetic macular edema is a vision-threatening complication of DR and a major cause of vision loss worldwide. Ocular treatments include retinal laser photocoagulation, anti-vascular endothelial growth factor (anti-VEGF) agents, intravitreal corticosteroids, and vitreoretinal surgery when necessary. The present consensus was developed as a part of the Saudi Retina Group's efforts to generate Saudi guidelines and consensus for the management of DME, including recommendations for its diagnosis, treatment, and best practice. The experts' panel stipulates that the treatment algorithm should be categorized according to the presence of central macula involvement. In patients with no central macular involvement, laser photocoagulation is recommended as the first-line option. Patients with central macular involvement and no recent history of cardiovascular (CVS) or cerebrovascular disorders can be offered anti-VEGF agents as the first-line option. In the case of non-responders (defined as an improvement of <20% in optical coherence tomography or a gain of fewer than 5 letters in vision), switching to another anti-VEGF agent or steroids should be considered after 3 injections. Within the class of steroids, dexamethasone implants are recommended as the first choice. In patients with a recent history of CVS events, the use of anti-VEGF agents is not recommended, regardless of their lens status. The experts' panel recommends that a future study be conducted to provide a cut-off point for early switching to steroid implants in pseudo-phakic eyes.

Differential associations between body mass index with diabetes and vision-threatening diabetic retinopathy in an adult Chinese population

PURPOSE

To investigate the associations between body mass index (BMI) with diabetes mellitus (DM) and vision-threatening diabetic retinopathy (VTDR).

METHODS

This was a longitudinal study which included DM-free participants aged ≥40 years from the Lingtou Eye Cohort Study at baseline (2008-2010). Physical and ocular examinations were performed at baseline and annual follow-ups under standardised protocol. Two 45° non-mydriatic colour digital retinal photographs were obtained for each eye at all study visits, and presence of VTDR at the 2016 follow-up was graded by a deep-learning algorithm (LableMe) with proved high accuracy for detection of VTDR.

RESULTS

A total of 2934 participants were included with a mean (SD) age of 59.5 (7.3) years (58.3% men). Participants with incident DM (441/2934, 15%) were significantly older (p<0.001), had higher obesity levels (p<0.001), higher systolic blood pressure (SBP) (p<0.001), diastolic blood pressure (p<0.001), fasting plasma glucose (FPG) (p<0.001), triglycerides (p=0.002) and high-density lipoprotein cholesterol (p<0.001), as compared with those without. Participants with incident VTDR (48/2934, 1.63%) were also older (p<0.001), had higher SBP (p=0.013) and FPG (p<0.001), but did not differ in baseline BMI, comparing with those without. Regression analysis showed that higher baseline BMI was significantly related to incident DM (p<0.005), but not incident VTDR, during the follow-up. Subgroup analysis among participants with incident DM also revealed no association between BMI and VTDR.

CONCLUSIONS

Higher baseline BMI increased the risk of incident DM, but was not related to the risk of VTDR in this adult Chinese population.

Effects of modified lipoproteins on human trophoblast cells: a role in pre-eclampsia in pregnancies complicated by diabetes

INTRODUCTION

Pre-eclampsia (PE) is increased ~4-fold by maternal diabetes. Elevated plasma antiangiogenic factors, soluble fms-like tyrosine kinase (sFLT-1) and soluble endoglin (sENG), precede PE onset. We investigated whether diabetes-related stresses, modified lipoproteins and elevated glucose enhance trophoblast sFLT-1 and sENG release and/or alter placental barrier function and whether oxidized low-density lipoprotein (Ox-LDL) is in placental tissue.

RESEARCH DESIGN AND METHODS

HTR8/SVneo cells were exposed to 'heavily-oxidized, glycated' LDL (HOG-LDL) versus native LDL (N-LDL) (10-200 mg protein/L) for 24 hours ±pretreatment with glucose (30 mmol/L, 72 hours). Concentrations of sFLT-1 and sENG in supernatants (by ELISA) and expressions of sFLT-1-I13 and sFLT-1-E15A isoforms, endoglin (ENG) and matrix metalloproteinase-14 (MMP-14; by RT-PCR) were quantified. For barrier studies, JAR cells were cultured in Transwell plates (12-14 days), then exposed to LDL. Transepithelial electrical resistance (TEER) was measured after 6, 12 and 24 hours. In placental sections from women with and without type 1 diabetes, immunostaining of apolipoprotein B100 (ApoB, a marker of LDL), Ox-LDL and lipoxidation product 4-hydroxynonenal was performed.

RESULTS

HOG-LDL (50 mg/L) increased sFLT-1 (2.7-fold, p<0.01) and sENG (6.4-fold, p<0.001) in supernatants versus N-LDL. HOG-LDL increased expression of sFLT-1-I13 (twofold, p<0.05), sFLT-1-E15A (1.9-fold, p<0.05), ENG (1.6-fold, p<0.01) and MMP-14 (1.8-fold, p<0.05) versus N-LDL. High glucose did not by itself alter sFLT-1 or sENG concentrations, but potentiated effects of HOG-LDL on sFLT-1 by 1.5-fold (p<0.05) and on sENG by 1.8-fold (p<0.01). HOG-LDL (200 mg/L) induced trophoblast barrier impairment, decreasing TEER at 6 hours (p<0.01), 12 hours (p<0.01) and 24 hours (p<0.05) versus N-LDL. Immunostaining of term placental samples from women both with and without diabetes revealed presence of intravillous modified lipoproteins.

CONCLUSION

These findings may explain, in part, the high risk for PE in women with diabetes. The trophoblast culture model has potential for evaluating novel therapies targeting barrier dysfunction.

Optical Coherence Tomography for Ophthalmology Imaging

Optical coherence tomography (OCT) is a depth-resolved imaging modality, which is able to achieve micrometer-scale resolution within biological tissue noninvasively. In the past 30 years, researchers all around the world had made several essential efforts on techniques relevant to OCT. OCT has become a routine process for eye diseases with different types. In this chapter, the three important stages in the development of OCT are briefly illustrated, including the time domain OCT (TD-OCT), the frequency domain OCT (FD-OCT) and the optical coherence tomography angiography (OCTA). Each of the technique has made great progress for use on living human eye imaging in clinical applications. TD-OCT was first proposed and commercialized, which is able to achieve acceptable 2D depth-resolved cross-sectional images of human retina in vivo. FD-OCT was the upgraded OCT technique compared with TD-OCT. By capturing the coherent signal within the Fourier space, the FD-OCT could improve the image sensitivity compared with TD-OCT, and achieve dozens of kilo hertz imaging speed. OCTA is the newest developments of OCT technique, which is able to visualize the micro vasculature networks of human retina in vivo. With OCTA technique, the newest ophthalmologic OCT system is able to achieve detailed diagnosis for both micro-structure and vasculature abnormalities for clinical applications. The further development of OCT technique on imaging speed, contrast, resolution, field of view, and so on will make OCT to be a more powerful tool for clinical usages.

Storm, typhoon, cyclone or hurricane in patients with COVID-19? Beware of the same storm that has a different origin

Some of the articles being published during the severe acute respiratory syndrome-coronavirus (SARS-CoV)-2 pandemic highlight a link between severe forms of coronavirus disease 2019 (COVID-19) and the so-called cytokine storm, also with increased ferritin levels. However, this scenario is more complex than initially thought due to the heterogeneity of hyperinflammation. Some patients with coronavirus 2019 disease (COVID-19) develop a fully blown secondary haemophagocytic lymphohistiocytosis (sHLH), whereas others, despite a consistent release of pro-inflammatory cytokines, do not fulfil sHLH criteria but still show some features resembling the phenotype of the hyperferritinemic syndrome. Despite the final event (the cytokine storm) is shared by various conditions leading to sHLH, the aetiology, either infectious, autoimmune or neoplastic, accounts for the differences in the various phases of this process. Moreover, the evidence of a hyperinflammatory microenvironment provided the rationale to employ immunomodulating agents for therapeutic purposes in severe COVID-19. This viewpoint aims at discussing the pitfalls and issues to be considered with regard to the use of immunomodulating agents in COVID-19, such as timing of treatment based on the viral load and the extent of cytokine/ferritin overexpression. Furthermore, it encompasses recent findings in the paediatric field about a novel multisystem inflammatory disease resembling toxic shock syndrome and atypical Kawasaki disease observed in children with proven SARS-CoV2 infection. Finally, it includes arguments in favour of adding COVID-19 to the spectrum of the recently defined 'hyperferritinemic syndrome', which already includes adult-onset Still's disease, macrophage activation syndrome, septic shock and catastrophic anti-phospholipid syndrome.

Detection of Diabetic Macular Edema in Optical Coherence Tomography Image Using an Improved Level Set Algorithm

Diabetic macular edema (DME) is a major cause of visual loss in the patients with diabetic retinopathy. DME detection in Optical Coherence Tomography (OCT) image contributes to the early diagnosis of diabetic retinopathy and blindness prevention. Currently, DME detection in the OCT image mainly relies on the handwork by the experienced clinician. It is a laborious, time-consuming, and challenging work to organize a comprehensive DME screening for diabetic patients. In this study, we proposed a novel algorithm for the detection and segmentation of DME region in OCT image based on the K-means clustering algorithm and improved Selective Binary and Gaussian Filtering regularized level set (SBGFRLS) algorithm named as SBGFRLS-OCT algorithm. SBGFRLS-OCT algorithm was compared with the current level set algorithms, including C-V (Chan-Vese), GAC (geodesic active contour), and SBGFRLS, to estimate the performance of DME detection. SBGFRLS-OCT algorithm was also compared with the clinician to estimate the precision, sensitivity, and specificity of DME segmentation. Compared with C-V, GAC, and SBGFRLS algorithm, the SBGFRLS-OCT algorithm enhanced the accuracy and reduces the processing time of DME detection. Compared with manual DME segmentation, the SBGFRLS-OCT algorithm achieved a comparable precision (97.7%), sensitivity (91.8%), and specificity (99.2%). Collectively, this study presents a novel algorithm for DME detection in the OCT image, which can be used for mass diabetic retinopathy screening.

ASSOCIATION BETWEEN EARLY ANATOMIC RESPONSE TO ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY AND LONG-TERM OUTCOME IN DIABETIC MACULAR EDEMA: An Independent Analysis of Protocol i Study Data

This retrospective analysis of Protocol I study data demonstrates a significant positive association between early (Week 12) retinal anatomical response and long-term (1- and 3-year) anatomical response with ranibizumab in center-involved diabetic macular edema. By contrast, early anatomical response was not significantly associated with long-term visual acuity response.

Purpose:

This post hoc analysis explores the relationship between early retinal anatomical response and long-term anatomical and visual outcomes with ranibizumab in center-involved diabetic macular edema.

Methods:

Eyes randomized to the ranibizumab plus prompt laser and ranibizumab plus deferred laser treatment arms in the Protocol I study were categorized according to their proportional reduction (<20 vs. ≥20%) in central retinal thickness (CRT) after 12 weeks. Adjusted and unadjusted analyses assessed the association between early (Week 12) anatomical response and long-term (Weeks 52 and 156) anatomical and best-corrected visual acuity outcomes.

Results:

Of 335 study eyes, 118 showed limited (<20%) and 217 showed strong (≥20%) CRT reduction at Week 12. In unadjusted and adjusted analyses, limited early CRT response was negatively and significantly associated with strong CRT response at Weeks 52 and 156. Sensitivity analyses indicated that this association was robust and unrelated to any “floor effect.” In unadjusted analyses, a strong early CRT response was associated with greater long-term improvement in best-corrected visual acuity; after controlling for confounders, the association lost statistical significance.

Conclusion:

Early CRT response to ranibizumab is a significant prognostic indicator of medium- to long-term anatomical outcome in center-involved diabetic macular edema.

Optical Coherence Tomography Biomarkers of the Outer Blood-Retina Barrier in Patients with Diabetic Macular Oedema

BACKGROUND

Numerous studies confirmed the main role of the inner blood-retinal barrier in the development of Diabetic Macular Oedema (DMO). Lately, the focus of research shifted towards the external retinal barrier with potential involvement in the pathogenesis of DMO.

OBJECTIVE

We aim to identify the OCT changes of the external blood-retinal barrier in patients with DMO and to define them as biomarkers with predictive value. Materials and method. We set up retrospectively 3 groups of patients diagnosed with nonproliferative diabetic retinopathy (NPDR) and DMO, proliferative diabetic retinopathy (PDR) and DMO, and controls. We compared the RPE thickness in every quadrant between groups and performed correlations between best-corrected visual acuity (BCVA) and the thickness of the retinal layers. The Social Science Statistics platform was used for statistical tests.

RESULTS

The NPDR-DMO group consisted of 18 eyes, the PDR-DMO group consisted of 19 eyes, and the control group included 36 eyes. In the PDR-DMO group, RPE thickness was decreased in almost all quadrants (p < 0.001); in the NPDR-DMO group, only the central minimum and central maximum values of the RPE thickness were significantly different from the control group. We did not find any strong correlation between BCVA and the thickness of the retinal layers.

CONCLUSION

The thickness of the RPE layer is an OCT biomarker able to predict the functioning of the outer BRB. Eyes with PDR-DMO exhibited decreased thickness of the RPE layer in almost all quadrants, highlighting the degenerative changes occurring in a hypoxic environment. The thickness of a specific layer could not be identified as a biomarker to correlate significantly with BCVA, most likely because we did not analyze specific morphologic features, such as continuity and reflectivity. The analysis of the RPE thickness could clarify the unexplained decrease of BCVA and predict early the evolution of DR.

Atrophy of the central neuroretina in patients treated for diabetic macular edema

Purpose

To examine the prevalence of central retinal atrophy in patients treated for diabetic macular edema (DME) in a clinical setting.

Methods

Retrospective data analysis of patients with DME, focusing on those who developed central retinal thinning after DME treatment at the Department of Ophthalmology, Medical University Vienna. Patient characteristics and clinical data including best‐corrected visual acuity (BCVA), spectral domain optical coherence tomography and fluorescence angiography images were reviewed and DME treatment strategies analysed using descriptive statistics. The correlation between visual acuity and ocular, systemic or DME treatment factors was calculated using linear regression models and ancovas.

Results

A total of 6684 outpatient visits by 1437 patients with diabetes were analysed. Out of 149 patients, who had had a central subfield thickness (CST) below 200 μm, 32 (36 eyes) had previously been diagnosed with a centre involving DME with an average CST of 473 ± 103 μm and average visual acuity of 0.62 ± 0.44 logMAR at first presentation. At the time of central atrophy, 29 (81%) out of 36 eyes had a history of laser treatment, 11 (31%) a vitrectomy, 32 (88%) repeated intravitreal injections of anti‐vascular endothelial growth factor (VEGF; mean 5.3 ± 3.8) and 22 (61%) intravitreal corticosteroid injections (mean 2.5 ± 2.7). Visual function (0.67 ± 0.43 logMAR) at the time of atrophy was not significantly correlated to central retinal thickness (191 ± 7 μm) or any other ocular, systemic or treatment factors.

Conclusions

Only 4% of patients treated for DME developed central retinal thinning in our observation period. On average, our atrophy patients had higher CST and lower BCVA when they first presented with DME compared to the overall DME cohort, and they received a combination of intravitreal injections and laser for DME treatment. Central retinal atrophy might not be attributed to excessive use of intravitreally applied anti‐VEGF or any other DME therapy alone.

Current methods for the assessment of skin microcirculation: Part 2

Microcirculation accounts for about 99% of blood vessels in adults and mediates between the arterial and venous parts of the cardiovascular system, both structurally and functionally. Skin microcirculation consists of two vascular plexuses: superficial and deep. Microcirculation includes vessels with a diameter of less than 150 μm, i.e. arteries, small veins, lymphatic vessels and arteriovenous anastomoses, which build the microcirculation unit. Skin microcirculation may be affected both in systemic pathologies and specific skin disorders. Several non-invasive techniques are available to assess the skin microcirculation. Methods used in clinical practice were presented previously in Advances in Dermatology and Allergology. The current article describes methods that may be used in clinical research.

Prevalence, Incidence and Ecological Determinants of Diabetic Retinopathy in Iran: Systematic Review and Meta-analysis

Purpose

To estimate the pooled prevalence and incidence of diabetic retinopathy (DR) in Iran and to investigate their correlations with the Human Development Index (HDI), healthcare access (i.e., density of specialists and sub-specialists), and methodological issues.

Methods

Electronic databases such as PubMed, Embase, Scopus, Web of Science, Google Scholar, and local databases were searched for cohort and cross-sectional studies published prior to January 2018. Prevalence and incidence rates of DR were extracted from January 2000 to December 2017 and random effects models were used to estimate pooled effect sizes. The Joanna Briggs Institute critical appraisal tool was applied for quality assessment of eligible studies.

Results

A total of 55,445 participants across 33 studies were included. The pooled prevalence (95% CI) of DR in diabetic clinics (22 studies), eye clinics (4 studies), and general population (7 studies) was 31.8% (24.5 to 39.2), 57.8% (50.2 to 65.3), and 29.6% (22.6 to 36.5), respectively. It was 7.4% (3.9 to 10.8) for proliferative DR and 7.1% (4.9 to 9.4) for clinically significant macular edema. The heterogeneity of individual estimates of prevalence was highly significant. HDI (P < 0.001), density of specialists (P = 0.004), subspecialists (P < 0.001), and sampling site (P = 0.041) were associated with heterogeneity after the adjustment for type of DR, duration of diabetes, study year, and proportion of diabetics with controlled HbA1C.

Conclusion

Human development and healthcare access were correlated with the prevalence of DR. Data were scarce on the prevalence of DR in less developed provinces. Participant recruitment in eye clinics might overestimate the prevalence of DR.

Increased risk of non-multiple sclerosis demyelinating syndromes in patients with preexisting septicaemia: a nationwide retrospective cohort study

Background

Growing evidence shows links between septicaemia and non-multiple sclerosis demyelinating syndromes (NMSDS); nevertheless, epidemiological data are still very limited. This study aimed to explore the relationship between septicaemia and NMSDS in a general population.

Methods

The study included 482 781 individuals diagnosed with septicaemia and 1 892 825 age/sex-matched non-septicaemia patients for the comparison. Data were drawn from a population-based nationwide National Health Insurance Research Database Taiwan, from 1 January 2002 to 31 December 2011. The two cohorts of patients with and without septicaemia were followed up for the occurrence of NMSDS. The Cox-proportional hazard regression model was performed to estimate adjusted HR after multivariate adjustment.

Results

Individuals with septicaemia had a 4.17-fold (95% CI 3.21 to 5.4, p < 0.001) higher risk to develop NMSDS compared with those without septicaemia. Patients aged <65 years had a greater NMSDS risk (<45 years: HR = 6.41, 95% CI 3.65 to 11.3, p < 0.001; 45–64 years: HR = 6.66, 95% CI 3.98 to 11.2, p < 0.001). Furthermore, females with septicaemia and individuals with higher severity of septicaemia were associated with increased risks of developing NMSDS.

Conclusions

Our results indicated that patients with septicaemia were likely to develop NMSDS. A possible contributing role of septicaemia in increasing the hazard of NMSDS is proposed, based on the outcome that individuals with higher severity of septicaemia carried elevated threat of encountering NMSDS.

Low-density granulocytes activate T cells and demonstrate a non-suppressive role in systemic lupus erythematosus

OBJECTIVES

The presence of proinflammatory low-density granulocytes (LDG) has been demonstrated in autoimmune and infectious diseases. Recently, regulatory neutrophilic polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) were identified in systemic lupus erythematosus (SLE). Because LDG and PMN-MDSC share a similar phenotype with contrasting functional effects, we explored these cells in a cohort of patients with SLE.

METHODS

LDG and normal-density granulocytes (NDG) were isolated from fresh blood of healthy donors (HD) and patients with SLE. Associations between LDG and clinical manifestations were analysed. Multicolor flow cytometry and confocal imaging were performed to immunophenotype the cells. The ability of LDG and NDG to suppress T cell function and induce cytokine production was quantified.

RESULTS

LDG prevalence was elevated in SLE versus HD, associated with the interferon (IFN) 21-gene signature and disease activity. Also, the LDG-to-lymphocyte ratio associated better with SLE disease activity index than neutrophil-to-lymphocyte ratio. SLE LDG exhibited significantly heightened surface expression of various activation markers and also of lectin-like oxidised low-density lipoprotein receptor-1, previously described to be associated with PMN-MDSC. Supernatants from SLE LDG did not restrict HD CD4⁺ T cell proliferation in an arginase-dependent manner, suggesting LDG are not immunosuppressive. SLE LDG supernatants induced proinflammatory cytokine production (IFN gamma, tumour necrosis factor alpha and lymphotoxin alpha) from CD4⁺ T cells.

CONCLUSIONS

Based on our results, SLE LDG display an activated phenotype, exert proinflammatory effects on T cells and do not exhibit MDSC function. These results support the concept that LDG represent a distinct proinflammatory subset in SLE with pathogenic potential, at least in part, through their ability to activate type 1 helper responses.

Optical coherence tomography patterns of diabetic macular edema in a Saudi population

Purpose: The study aims to describe the patterns of diabetic macular edema (DME) and their association with visual acuity using optical coherence tomography (OCT). Patients and methods: This is a retrospective observational study with chart review of patients with DME including both type 1 and 2 diabetics seen between January 2015 and January 2016. Main Outcome Measures: Type of diabetes, diabetes duration, best-corrected visual acuity, DME pattern, central macular thickness (CMT), and stage of diabetic retinopathy. DME was classified based on OCT scans into: sponge-like diffuse retinal thickness (SLDRT), cystoids macular edema (CME), and sub-retinal fluid (SRF). Results: 227 eyes (144 patients) were included. The SLDRT represented 67.84%, CME 19.82%, and presence of SRF 2.20%. OCT scan from 21 patients (22 eyes) displayed more than a single pattern. The CMT and visual acuities varied depending on the DME morphologic patterns. SLDRT was associated with the least affected mean visual acuity of 0.2±0.21. SRF signified the worst mean visual acuities. Increase in CMT significantly correlated with reduced visual acuity (P=0.005). A statistically significant positive correlations between diabetic stage-high risk proliferative diabetic retinopathy (PDR) and severe non-proliferative diabetic retinopathy (NPDR)-with the CMT (P=0.050) and (P=0.021) respectively, were observed. A significant positive correlation between the duration of diabetes, age and type 1 diabetes with visual acuity in LogMAR (P=0.003), (P=0.03), and (P=0.0005) respectively. Conclusions: SLDRT was the most common morphological subtype of DME patterns and increasing retinal thickness impaired the visual acuity. Older ages, longer diabetic duration and type 1 diabetes are considered significant risk factors for visual acuity impairment. The study also suggests that there is a significant correlation between the DME patterns and visual acuity.

Multimodal OCT Reflectivity Analysis of the Cystoid Spaces in Cystoid Macular Edema

Purpose

To compare and evaluate images of macular cysts with different degrees of reflectivity (from gray to black signal) as observed in B scan spectral domain OCT (SDOCT) and EnFace OCT with decorrelation signal obtained with OCT-angiography (OCTA) in eyes with cystoid macular edema (CME) secondary to diabetic retinopathy (DR) and retinal vein occlusion (RVO).

Methods

Images from 3033 patients affected by CME secondary to diabetes or RVO examined OCTA (Optovue XR Avanti, Optovue, USA) at the University Eye Clinic of Créteil, Hôpital Intercommunal, France, and at the University Eye Clinic of Cagliari, “San Giovanni di Dio” Hospital, Italy, were retrospectively examined. The deep capillary plexus OCTA images and the corresponding EnFace OCT images, both acquired with the same automatic segmentation, had been overlapped to compose RGB color images as red and green channels, respectively, using ImageJ software (National Institutes of Health, Bethesda, MD). Afterward, linear regions of interest were traced on the color images to obtain the profiles of OCTA and EnFace gray values. Number of pixels, mean gray value and standard deviation of the area traced in OCT-A, and EnFace image were analyzed and statistically correlated. Data were exported to Excel to create the plots.

Results

94 patients with DME and 27 patients with RVO showed intraretinal macular cystoid spaces with similar homogeneous, gray-looking content; 73 patients with DME and 113 patients with RVO showed macular cystoid spaces with homogeneous, black-looking content, as observed at SD-OCT, EnFace and OCTA scans. Interestingly, the limits of macular cystoid spaces were clearly detectable with OCTA. The analysis of red and green profiles demonstrated a clearly visible overlap between average OCTA and EnFace signal observed around cystoid spaces that could be attributed to a relationship between the dynamic vascularization and the structural density of the tissue.

Conclusions

This is the first investigation that characterizes and correlates OCTA and EnFace signals on images of macular cystoid spaces in DR and RVO. The low intensity OCTA signals observed inside cystoid spaces raise a relevant question about their nature, as to whether they are due to the presence of corpusculated material pouring out from bloodocular-barrier or they should be considered OCTA artifacts.

Observational study of the status of coronary risk biomarkers among Negritos with metabolic syndrome in the east coast of Malaysia

OBJECTIVES

To determine the prevalence of metabolic syndrome (MS), ascertain the status of coronary risk biomarkers and establish the independent predictors of these biomarkers among the Negritos.

SETTINGS

Health screening programme conducted in three inland settlements in the east coast of Malaysia and Peninsular Malaysia.

SUBJECTS

150 Negritos who were still living in three inland settlements in the east coast of Malaysia and 1227 Malays in Peninsular Malaysia. These subjects were then categorised into MS and non-MS groups based on the International Diabetes Federation (IDF) consensus worldwide definition of MS and were recruited between 2010 and 2015. The subjects were randomly selected and on a voluntary basis.

PRIMARY AND SECONDARY OUTCOME MEASURES

This study was a cross-sectional study. Serum samples were collected for analysis of inflammatory (hsCRP), endothelial activation (sICAM-1) and prothrombogenesis [lp(a)] biomarkers.

RESULTS

MS was significantly higher among the Malays compared with Negritos (27.7%vs12.0%). Among the Malays, MS subjects had higher hsCRP (p=0.01) and sICAM-1 (p<0.05) than their non-MS counterpart. There were no significant differences in all the biomarkers between MS and the non-MS Negritos. However, when compared between ethnicity, all biomarkers were higher in Negritos compared with Malays (p<0.001). Binary logistic regression analysis affirmed that Negritos were an independent predictor for Lp(a) concentration (p<0.001).

CONCLUSIONS

This study suggests that there may possibly be a genetic influence other than lifestyle, which could explain the lack of difference in biomarkers concentration between MS and non-MS Negritos and for Negritos predicting Lp(a).

Multilayered Deep Structure Tensor Delaunay Triangulation and Morphing Based Automated Diagnosis and 3D Presentation of Human Macula

Maculopathy is the group of diseases that affects central vision of a person and they are often associated with diabetes. Many researchers reported automated diagnosis of maculopathy from optical coherence tomography (OCT) images. However, to the best of our knowledge there is no literature that presents a complete 3D suite for the extraction as well as diagnosis of macula. Therefore, this paper presents a multilayered convolutional neural networks (CNN) structure tensor Delaunay triangulation and morphing based fully autonomous system that extracts up to nine retinal and choroidal layers along with the macular fluids. Furthermore, the proposed system utilizes the extracted retinal information for the automated diagnosis of maculopathy as well as for the robust reconstruction of 3D macula of retina. The proposed system has been validated on 41,921 retinal OCT scans acquired from different OCT machines and it significantly outperformed existing state of the art solutions by achieving the mean accuracy of 95.27% for extracting retinal and choroidal layers, mean dice coefficient of 0.90 for extracting fluid pathology and the overall accuracy of 96.07% for maculopathy diagnosis. To the best of our knowledge, the proposed framework is first of its kind that provides a fully automated and complete 3D integrated solution for the extraction of candidate macula along with its fully automated diagnosis against different macular syndromes.

Assessment of Global and Local Alterations in Retinal Layer Thickness in Ins2 (Akita) Diabetic Mice by Spectral Domain Optical Coherence Tomography

PURPOSE/AIM

The Ins2 (Akita) mouse is a spontaneous diabetic mouse model with a heterozygous mutation in the insulin 2 gene that results in sustained hyperglycemia. The purpose of the study was to assess global and local retinal layer thickness alterations in Akita mice by analysis of spectral domain optical coherence tomography (SD-OCT) images.

MATERIALS AND METHODS

SD-OCT imaging was performed in Akita and wild-type mice at 12 and 24 weeks of age. Inner retinal thickness (IRT), outer retinal thickness (ORT), total retinal thickness (TRT), and photoreceptor outer segment length (OSL) were measured. Mean global thickness values were compared between Akita and wild-type mice. Local thickness variations in Akita mice were assessed based on normative values in wild-type mice.

RESULTS

Akita mice had higher blood glucose levels and lower body weights (p < 0.001). On average, IRT, ORT, and TRT were approximately 2% lower in Akita mice than in wild-type mice (p ≤ 0.02). In Akita mice, the percent difference between retinal areas with thickness below and above normative values for IRT, ORT, and TRT was 22%, 32%, and 38%, respectively.

CONCLUSIONS

These findings support the use of the Akita mouse model to study the retinal neurodegenerative effects of hyperglycemia.

Nintedanib inhibits macrophage activation and ameliorates vascular and fibrotic manifestations in the Fra2 mouse model of systemic sclerosis

Background

Nintedanib is an inhibitor targeting platelet-derived growth factor receptor, fibroblast growth factor receptor and vascular endothelial growth factor receptor tyrosine kinases that has recently been approved for the treatment of idiopathic pulmonary fibrosis. The aim of this study was to analyse the effects of nintedanib in the fos-related antigen-2 (Fra2) mouse model of systemic sclerosis (SSc).

Methods

The effects of nintedanib on pulmonary arterial hypertension with proliferation of pulmonary vascular smooth muscle cells (PVSMCs) and luminal occlusion, on microvascular disease with apoptosis of microvascular endothelial cells (MVECs) and on fibroblast activation with myofibroblast differentiation and accumulation of extracellular matrix were analysed. We also studied the effects of nintedanib on the levels of key mediators involved in the pathogenesis of SSc and on macrophage polarisation.

Results

Nintedanib inhibited proliferation of PVSMCs and prevented thickening of the vessel walls and luminal occlusion of pulmonary arteries. Treatment with nintedanib also inhibited apoptosis of MVECs and blunted the capillary rarefaction in Fra2-transgenic mice. These effects were associated with a normalisation of the serum levels of vascular endothelial growth factor in Fra2 mice on treatment with nintedanib. Nintedanib also effectively blocked myofibroblast differentiation and reduced pulmonary, dermal and myocardial fibrosis in Fra2-transgenic mice. The antifibrotic effects of nintedanib were associated with impaired M2 polarisation of monocytes and reduced numbers of M2 macrophages.

Conclusion

Nintedanib targets core features of SSc in Fra2-transgenic mice and ameliorates histological features of pulmonary arterial hypertension, destructive microangiopathy and pulmonary and dermal fibrosis. These data might have direct implications for the ongoing phase III clinical trial with nintedanib in SSc-associated interstitial lung disease.

Comparing Macular Thickness Measurements in Patients with Diabetic Macular Edema with the Optos Spectral OCT/SLO and Heidelberg Spectralis HRA + OCT

The aim of this study was to compare measurements of macular thickness, obtained from patients with diabetic macular edema, using two spectral-domain optical coherence tomography (SD-OCT) devices. These were the Spectralis Heidelberg Retina Angiograph + Optical Coherence Tomography (HRA + OCT) (Heidelberg Engineering), which is often considered the gold-standard for OCT measurement, and the Spectral Optical Coherence Tomography/Scanning Laser Ophthalmoscopy (OCT/SLO) (Optos plc), which can additionally perform microperimetry, a useful measure of visual function. In this prospective observational study, each eye had SD-OCT performed with both devices on the same day by the same investigator. Mean retinal thickness was calculated, and compared between the devices, for central and parafoveal zones within 3 mm of the fovea. 62 eyes were included. In the central, superior, temporal, inferior and nasal zones respectively, mean retinal thickness with Spectralis HRA+OCT was (in microns) 310, 343, 344, 332 and 340; measurements with Spectral OCT/SLO were 237, 298, 297, 289 and 290. Pearson correlations between the devices were 0.752, 0.85, 0.928, 0.839, and 0.823 (p < 0.0001). Although absolute measurements between the devices were significantly different and therefore not interchangeable, the correlation between the devices was over 75% and statistically significant in all zones. Thus, the Spectral OCT/SLO could reliably be used for SD-OCT in patients who may also require microperimetry assessment.

Novel strategies for the treatment of diabetic macular edema

Macular edema such as diabetic macular edema (DME) and diabetic retinopathy are devastating back-of-the-eye retinal diseases leading to loss of vision. This area is receiving considerable medical attention. Posterior ocular diseases are challenging to treat due to complex ocular physiology and barrier properties. Major ocular barriers are static (corneal epithelium, corneal stroma, and blood-aqueous barrier) and dynamic barriers (blood-retinal barrier, conjunctival blood flow, lymph flow, and tear drainage). Moreover, metabolic barriers impede posterior ocular drug delivery and treatment. To overcome such barriers and treat back-of-the-eye diseases, several strategies have been recently developed which include vitreal drainage, laser photocoagulation and treatment with biologics and/or small molecule drugs. In this article, we have provided an overview of several emerging novel strategies including nanotechnology based drug delivery approach for posterior ocular drug delivery and treatment with an emphasis on DME.

Contemporary retinal imaging techniques in diabetic retinopathy: a review

Over the last decade, there has been an expansion of imaging modalities available to clinicians to diagnose and monitor the treatment and progression of diabetic retinopathy. Recently, advances in image technologies related to OCT and OCT angiography have enabled improved visualization and understanding of this disease. In this review, we will describe the use of imaging techniques such as colour fundus photography, fundus autofluorescence, fluorescein angiography, infrared reflectance imaging, OCT, OCT-Angiography and techniques in adaptive optics and hyperspectral imaging in the diagnosis and management of diabetic retinopathy.

New Diagnostic and Therapeutic Approaches for Preventing the Progression of Diabetic Retinopathy

Diabetic retinopathy (DR) is a severe sight-threatening complication of diabetes mellitus. Retinal laser photocoagulation, antivascular endothelial growth factors, steroid therapy, and pars plana vitrectomy are now used extensively to treat advanced stages of diabetic retinopathy. Currently, diagnostic devices like ultrawide field fundus fluorescein angiography and the improvement of optical coherence tomography have provided quicker and more precise diagnosis of early diabetic retinopathy. Thus, treatment protocols have been modified accordingly. Various types of lasers, including the subthreshold micropulse laser and RPE-targeting laser, and selective targeted photocoagulation may be future alternatives to conventional retinal photocoagulation, with fewer complications. The new developed intravitreal medications and implants have provided more therapeutic options, with promising results.

Enface Thickness Mapping and Reflectance Imaging of Retinal Layers in Diabetic Retinopathy

Purpose

To present a method for image segmentation and generation of enface thickness maps and reflectance images of retinal layers in healthy and diabetic retinopathy (DR) subjects.

Methods

High density spectral domain optical coherence tomography (SDOCT) images were acquired in 10 healthy and 4 DR subjects. Customized image analysis software identified 5 retinal cell layer interfaces and generated thickness maps and reflectance images of the total retina (TR), inner retina (IR), outer retina (OR), and the inner segment ellipsoid (ISe) band. Thickness maps in DR subjects were compared to those of healthy subjects by generating deviation maps which displayed retinal locations with thickness below, within, and above the normal 95% confidence interval.

Results

In healthy subjects, TR and IR thickness maps displayed the foveal depression and increased thickness in the parafoveal region. OR and ISe thickness maps showed increased thickness at the fovea, consistent with normal retinal anatomy. In DR subjects, thickening and thinning in localized regions were demonstrated on TR, IR, OR, and ISe thickness maps, corresponding to retinal edema and atrophy, respectively. TR and OR reflectance images showed reduced reflectivity in regions of increased thickness. Hard exudates appeared as hyper-reflective spots in IR reflectance images and casted shadows on the deeper OR and ISe reflectance images. The ISe reflectance image clearly showed the presence of focal laser scars.

Conclusions

Enface thickness mapping and reflectance imaging of retinal layers is a potentially useful method for quantifying the spatial and axial extent of pathologies due to DR.

Application of different imaging modalities for diagnosis of Diabetic Macular Edema: A review

Diabetic Macular Edema (DME) is caused by accumulation of extracellular fluid from hyperpermeable capillaries within the macula. DME is one of the leading causes of blindness among Diabetes Mellitus (DM) patients. Early detection followed by laser photocoagulation can save the visual loss. This review discusses various imaging modalities viz. biomicroscopy, Fluorescein Angiography (FA), Optical Coherence Tomography (OCT) and colour fundus photographs used for diagnosis of DME. Various automated DME grading systems using retinal fundus images, associated retinal image processing techniques for fovea, exudate detection and segmentation are presented. We have also compared various imaging modalities and automated screening methods used for DME grading. The reviewed literature indicates that FA and OCT identify DME related changes accurately. FA is an invasive method, which uses fluorescein dye, and OCT is an expensive imaging method compared to fundus photographs. Moreover, using fundus images DME can be identified and automated. DME grading algorithms can be implemented for telescreening. Hence, fundus imaging based DME grading is more suitable and affordable method compared to biomicroscopy, FA, and OCT modalities.

Imaging in diabetic retinopathy

While the primary method for evaluating diabetic retinopathy involves direct and indirect ophthalmoscopy, various imaging modalities are of significant utility in the screening, evaluation, diagnosis, and treatment of different presentations and manifestations of this disease. This manuscript is a review of the important imaging modalities that are used in diabetic retinopathy, including color fundus photography, fluorescein angiography, B-scan ultrasonography, and optical coherence tomography. The article will provide an overview of these different imaging techniques and how they can be most effectively used in current practice.

In vivo microvascular network imaging of the human retina combined with an automatic three-dimensional segmentation method

Microvascular network of the retina plays an important role in diagnosis and monitoring of various retinal diseases. We propose a three-dimensional (3-D) segmentation method with intensity-based Doppler variance (IBDV) based on swept-source optical coherence tomography. The automatic 3-D segmentation method is used to obtain seven surfaces of intraretinal layers. The microvascular network of the retina, which is acquired by the IBDV method, can be divided into six layers. The microvascular network of the six individual layers is visualized, and the morphology and contrast images can be improved by using the segmentation method. This method has potential for earlier diagnosis and precise monitoring in retinal vascular diseases.

Schizophrenia and the eye

Although visual processing impairments are common in schizophrenia, it is not clear to what extent these originate in the eye vs. the brain. This review highlights potential contributions, from the retina and other structures of the eye, to visual processing impairments in schizophrenia and high-risk states. A second goal is to evaluate the status of retinal abnormalities as biomarkers for schizophrenia. The review was motivated by known retinal changes in other disorders (e.g., Parkinson’s disease, multiple sclerosis), and their relationships to perceptual and cognitive impairments, and disease progression therein. The evidence reviewed suggests two major conclusions. One is that there are multiple structural and functional disturbances of the eye in schizophrenia, all of which could be factors in the visual disturbances of patients. These include retinal venule widening, retinal nerve fiber layer thinning, dopaminergic abnormalities, abnormal ouput of retinal cells as measured by electroretinography (ERG), maculopathies and retinopathies, cataracts, poor acuity, and strabismus. Some of these are likely to be illness-related, whereas others may be due to medication or comorbid conditions. The second conclusion is that certain retinal findings can serve as biomarkers of neural pathology, and disease progression, in schizophrenia. The strongest evidence for this to date involves findings of widened retinal venules, thinning of the retinal nerve fiber layer, and abnormal ERG amplitudes. These data suggest that a greater understanding of the contribution of retinal and other ocular pathology to the visual and cognitive disturbances of schizophrenia is warranted, and that retinal changes have untapped clinical utility.

Kernel regression based segmentation of optical coherence tomography images with diabetic macular edema

We present a fully automatic algorithm to identify fluid-filled regions and seven retinal layers on spectral domain optical coherence tomography images of eyes with diabetic macular edema (DME). To achieve this, we developed a kernel regression (KR)-based classification method to estimate fluid and retinal layer positions. We then used these classification estimates as a guide to more accurately segment the retinal layer boundaries using our previously described graph theory and dynamic programming (GTDP) framework. We validated our algorithm on 110 B-scans from ten patients with severe DME pathology, showing an overall mean Dice coefficient of 0.78 when comparing our KR + GTDP algorithm to an expert grader. This is comparable to the inter-observer Dice coefficient of 0.79. The entire data set is available online, including our automatic and manual segmentation results. To the best of our knowledge, this is the first validated, fully-automated, seven-layer and fluid segmentation method which has been applied to real-world images containing severe DME.

Polycystic ovary syndrome: aggressive or protective factor for the retina? Evaluation of macular thickness and retinal nerve fiber layers using high-definition optical coherence tomography

Objective. To compare macular thickness (MT) and retinal nerve fiber layers (RNFL) between women with polycystic ovary syndrome (PCOS) and healthy women. Materials and Methods. The study included 45 women with PCOS and 47 ovulatory women undergoing clinical-gynecological and ophthalmic evaluations, including measurement of MT, RNFL, and optic disc parameters using optical coherence tomography. Results. The superior RNFL around the optic nerve was significantly thicker in PCOS than in healthy volunteers (P = 0.036). After stratification according to insulin resistance, the temporal inner macula (TIM), the inferior inner macula (IIM), the nasal inner macula (NIM), and the nasal outer macula (NOM) were significantly thicker in PCOS group than in control group (P < 0.05). Both the presence of obesity associated with insulin resistance (P = 0.037) and glucose intolerance (P = 0.001) were associated with significant increase in the PC1 mean score, relative to MT. A significant increase in the PC2 mean score occurred when considering the presence of metabolic syndrome (P < 0.0001). There was a significant interaction between obesity and inflammation in a decreasing mean PC2 score relative to macular RNFL thickness (P = 0.034). Conclusion. Decreased macular RNFL thickness and increased total MT are associated with metabolic abnormalities, while increased RNFL thickness around the optic nerve is associated with hormonal changes inherent in PCOS.

Application of an OCT data-based mathematical model of the foveal pit in Parkinson disease

Spectral-domain Optical coherence tomography (OCT) has shown remarkable utility in the study of retinal disease and has helped to characterize the fovea in Parkinson disease (PD) patients. We developed a detailed mathematical model based on raw OCT data to allow differentiation of foveae of PD patients from healthy controls. Of the various models we tested, a difference of a Gaussian and a polynomial was found to have "the best fit". Decision was based on mathematical evaluation of the fit of the model to the data of 45 control eyes versus 50 PD eyes. We compared the model parameters in the two groups using receiver-operating characteristics (ROC). A single parameter discriminated 70 % of PD eyes from controls, while using seven of the eight parameters of the model allowed 76 % to be discriminated. The future clinical utility of mathematical modeling in study of diffuse neurodegenerative conditions that also affect the fovea is discussed.