Safety of indocyanine green angiography during pregnancy: a survey of the retina, macula, and vitreous societies

Indocyanine Green-Labeled Platelets for Survival and Recovery Studies

Introduction

Before being implemented in daily clinical routine, new production strategies for platelet concentrates (PCs) must be validated for their efficacy. Besides in vitro testing, the establishment of new methods requires the labeling of platelets for in vivo studies of platelets' survival and recovery. Indocyanine green (ICG) is a Food and Drug Administration-approved near-infrared (NIR) fluorescent dye for diagnostic use in vivo, suitable for non-radioactive direct cell labeling of platelets.

Methods

Platelets from PCs in storage solutions with different plasma concentrations were labeled with ICG up to concentrations of 200 μm. Whole blood (WB) was used as an ex vivo matrix to monitor the labeling stability of ICG-labeled platelets. The impact of labeling processes was assessed by the quantification of CD62P expression and PAC-1 binding as platelet function markers. Platelet aggregation was analyzed by light transmission aggregometry. ICG-labeling efficiency and stability of platelets were determined by flow cytometry.

Results

Platelets from PCs could be successfully labeled with 10 μm ICG after 1 and 4 days of storage. The best labeling efficiency of 99.8% ± 0.1% (immediately after labeling) and 81% ± 6.2% (after 24 h incubation with WB) was achieved by plasma replacement by 100% platelet additive solution for the labeling process. Since the washing process slightly impaired platelet function, ICG labeling itself did not affect platelets. Immediately after the ICG-labeling process, plasma was re-added, resulting in a recovered platelet function.

Conclusion

We developed a Good Manufacturing Practice compatible protocol for ICG fluorescent platelet labeling suitable for survival and recovery studies in vivo as a non-radioactive labeling alternative.

Respiratory and locomotor muscle blood flow measurements using near-infrared spectroscopy and indocyanine green dye in health and disease

Measuring respiratory and locomotor muscle blood flow during exercise is pivotal for understanding the factors limiting exercise tolerance in health and disease. Traditional methods to measure muscle blood flow present limitations for exercise testing. This article reviews a method utilising near-infrared spectroscopy (NIRS) in combination with the light-absorbing tracer indocyanine green dye (ICG) to simultaneously assess respiratory and locomotor muscle blood flow during exercise in health and disease. NIRS provides high spatiotemporal resolution and can detect chromophore concentrations. Intravenously administered ICG binds to albumin and undergoes rapid metabolism, making it suitable for repeated measurements. NIRS-ICG allows calculation of local muscle blood flow based on the rate of ICG accumulation in the muscle over time. Studies presented in this review provide evidence of the technical and clinical validity of the NIRS-ICG method in quantifying respiratory and locomotor muscle blood flow. Over the past decade, use of this method during exercise has provided insights into respiratory and locomotor muscle blood flow competition theory and the effect of ergogenic aids and pharmacological agents on local muscle blood flow distribution in COPD. Originally, arterial blood sampling was required via a photodensitometer, though the method has subsequently been adapted to provide a local muscle blood flow index using venous cannulation. In summary, the significance of the NIRS-ICG method is that it provides a minimally invasive tool to simultaneously assess respiratory and locomotor muscle blood flow at rest and during exercise in health and disease to better appreciate the impact of ergogenic aids or pharmacological treatments.

Vortex Veins in Eyes With Pachychoroid Spectrum Disorders Evaluated by the Adjusted Reverse 3-Dimensional Projection Model

Purpose

To compare the distribution of vortex vein ampulla (VVA) between pachychoroid spectrum disorder (PSD) and controls.

Design

A single-center, case-control study.

Participants

This study included 75 PSD, 35 fellow, and 65 control eyes.

Methods

We quantified VVA distribution using a 3-dimensional reverse projection model corrected for image distortion. We investigated the distribution of major drainage veins (MDV), in which macular Haller's vessels directly influx.

Main Outcome Measures

The mean distances from the optic disc to VVAs and the mean angles between VVAs and the fovea-disc line.

Results

The PSD group had significantly fewer VVA in infranasal sector (PSD, fellow, control; 1.6 ± 0.6, 1.8 ± 0.6, 1.9 ± 0.6, respectively, P = 0.026). In supralateral sector, for PSD, fellows, and controls, the mean distances from the optic disc to VVAs were 14.1 ± 1.0 mm, 14.1 ± 1.1 mm, and 13.6 ± 1.4 mm, respectively, and were significantly farther in PSD than in controls (P = 0.023). The mean angles between VVAs and the fovea-disc line were 64.8 ± 5.9°, 66.4 ± 6.4°, and 61.7 ± 6.4°, respectively, and were significantly higher in PSD and fellows than in controls (P = 0.008). The mean distances from the optic disc to MDV in supratemporal sector were 14.1 ± 1.2 and 13.7 ± 1.2 in eyes whose Haller's vessels extended beyond the fovea-disc line (asymmetry), and those that did not, respectively, with the asymmetric eyes significantly farther (P = 0.016).

Conclusions

The VVA position in supralateral sector was farther and higher in PSD than in controls, suggesting that the distribution of VVA may be associated with the development of PSD.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Feasibility of indocyanine green-guided localization of pulmonary nodules in children with solid tumors

BACKGROUND

Clearing all pulmonary metastases is essential for curing pediatric solid tumors. However, intraoperative localization of such pulmonary nodules can be challenging. Therefore, an intraoperative tool that localizes pulmonary metastases is needed to improve diagnostic and therapeutic resections. Indocyanine green (ICG) real-time fluorescence imaging is used for this purpose in adult solid tumors, but its utility in pediatric solid tumors has not been determined.

METHODS

A single-center, open-label, nonrandomized, prospective clinical trial (NCT04084067) was conducted to assess the ability of ICG to localize pulmonary metastases of pediatric solid tumors. Patients with pulmonary lesions who required resection, either for therapeutic or diagnostic intent, were included. Patients received a 15-minute intravenous infusion of ICG (1.5 mg/kg), and pulmonary metastasectomy was performed the following day. A near-infrared spectroscopy iridium system was optimized to detect ICG, and all procedures were photo-documented and recorded.

RESULTS

ICG-guided pulmonary metastasectomies were performed in 12 patients (median age: 10.5 years). A total of 79 nodules were visualized, 13 of which were not detected by preoperative imaging. Histologic examination confirmed the following histologies: hepatoblastoma (n = 3), osteosarcoma (n = 2), and one each of rhabdomyosarcoma, Ewing sarcoma, inflammatory myofibroblastic tumor, atypical cartilaginous tumor, neuroblastoma, adrenocortical carcinoma, and papillary thyroid carcinoma. ICG guidance failed to localize pulmonary metastases in five (42%) patients who had inflammatory myofibroblastic tumor, atypical cartilaginous tumor, neuroblastoma, adrenocortical carcinoma, or papillary thyroid carcinoma.

CONCLUSIONS

ICG-guided identification of pulmonary nodules is not feasible for all pediatric solid tumors. However, it may localize most metastatic hepatic tumors and high-grade sarcomas in children.

Clinical Applications of Optical Coherence Tomography Angiography in Inherited Retinal Diseases: An Up-to-Date Review of the Literature

Optical coherence tomography angiography (OCT-A) is a valuable imaging technique, allowing non-invasive, depth-resolved, motion-contrast, high-resolution images of both retinal and choroidal vascular networks. The imaging capabilities of OCT-A have enhanced our understanding of the retinal and choroidal alterations that occur in inherited retinal diseases (IRDs), a group of clinically and genetically heterogeneous disorders that may be complicated by several vascular conditions requiring a prompt diagnosis. In this review, we aimed to comprehensively summarize all clinical applications of OCT-A in the diagnosis and management of IRDs, highlighting significant vascular findings on retinitis pigmentosa, Stargardt disease, choroideremia, Best disease and other less common forms of retinal dystrophies. All advantages and limitations of this novel imaging modality will be also discussed.

Idiopathic multifocal choroiditis and punctate inner choroidopathy: an evaluation in pregnancy

Purpose

To evaluate the clinical course of idiopathic multifocal choroiditis (MFC) and punctate inner choroidopathy (PIC) and the efficacy and safety of treatment options during pregnancy.

Methods

Patients with MFC or PIC and a pregnancy in 2011–2019 from two academic centres were enrolled. For the most recent pregnancy, data on best‐corrected visual acuity (BCVA) before and after pregnancy, relapse rate in pregnancy and postpartum period and obstetric, maternal and neonatal outcomes were collected. Treatment regimens consisted of a wait‐and‐see regime and an immunosuppressive treatment regime with systemic corticosteroids and/or azathioprine, both combined with intravitreal antivascular endothelial growth factor injections when indicated.

Results

Sixteen women (26 affected eyes) were included. Median Snellen BCVA was 20/19 before pregnancy and 20/18 after delivery. In seven pregnancies a wait‐and‐see regime and in nine pregnancies an immunosuppressive treatment regime was carried out. Fourteen intravitreal anti‐VEGF injections were given in six pregnancies. The relapse rate during pregnancy was 44% and in the postpartum period 31%. Maternal/obstetrical and fetal complications occurred in 31% and 13% of the pregnancies, respectively. Fifteen healthy children were born and one pregnancy ended in a stillbirth in a patient with a complicated obstetrical history. One patient treated with azathioprine developed intrahepatic cholestasis of pregnancy (ICP).

Conclusions

Among women with MFC and PIC BCVA remained stable during pregnancy despite a relapse rate of 44% in pregnancy. No major maternal, obstetric and fetal complications occurred in pregnant patients treated with systemic corticosteroids, azathioprine or intravitreal anti‐VEGF injections, though one patient developed ICP while treated with azathioprine.

Diabetic retinopathy in pregnancy - A review

Diabetes and gestational diabetes (GD) are areas of concern worldwide. GD can eventually lead to serious development of diabetic retinopathy (DR) during pregnancy or worsening of an already existing DR. GD confers future risk of diabetes, both in the mother and fetus, further complicating their lives. DR in pregnant women has been intriguing in terms of understanding the prevalence, assessing risk factors causing pathogenesis, and problems associated with treating them. Pregnancy itself is a risk factor for progression of DR. Physiological changes such as metabolic, vascular, immunologic, and hormonal changes that occur during pregnancy can cause development as well as worsening of DR. This can eventually lead to permanent visual loss if not addressed on time. Timing of laser, choice of treatment for diabetic macular edema with laser, intravitreal anti-vascular endothelial growth factor agents (VEGF), and intravitreal steroids pose a serious challenge in managing these patients without causing damage to the mother and fetus. This review article showcases the prevalence, risk factors, and pathogenesis, outlines the management of DR in pregnancy, and recommends guidelines based on the available evidence. PubMed and MEDLINE searches were performed pertaining to the prevalence of GD in India, DR in pregnancy, risk factors for progression of DR, role of vasoactive mediators in DR, role of angiopoietic factors in DR, hormonal influence of DR, role of growth factors in DR, use of fluorescein and indocyanine green angiography, retinal lasers, anti-VEGF agents, intravitreal steroids, anesthesia, and retinal surgery, all pertaining to pregnancy and guidelines and recommendations for managing DR in pregnancy.

Maternal-fetal transfer of indocyanine green: a systematic review

RATIONAL

In a survey of 1101 members of vitreoretinal trained physicians regarding the use of ICG angiography during pregnancy, 434 (83%) of 520 respondents had seen at least one pregnant woman requiring ICG angiography or fluorescein angiography. One hundred and five (24%) withheld ICG angiography, mostly because of fear of teratogenicity or lawsuit. Adverse reactions to fluorescein and ICG are rare and may be classified as toxic, hypersensitivity, and non-specific. This literature review aimed to review evaluate the maternal-to-fetal transfer of ICG and resume the most recent recommendations for ICG use in its obstetric applications.

METHODS

The available literature was examined using PubMed-Medline, and web of science, and using the MeSH terms "fluorescein," "Indocyanine green," and "pregnancy" according to PRISMA-P guidelines.

RESULTS

Studies in humans demonstrated that ICG is not detectable in fetal cord blood or umbilical vein blood collected immediately after birth. ICG maternal-to-fetal transfer is slow and is safe during pregnancy. ICG in the fetus accumulates in the liver and accumulation is enhanced by the administration of OATPs or P-gp inhibitors.

CONCLUSIONS

ICG's transplacental transfer is minimal and is probably medicine-mediated, like rifampin. The placenta is an effective protective barrier to ICG's distribution into the fetus.

Comprehensive Review of Fluorescence Applications in Gynecology

Since the introduction of indocyanine green (ICG) as a fluorophore in near-infrared imaging, fluorescence visualization has become an essential tool in many fields of surgery. In the field of gynecology, recent new applications have been proposed and found their place in clinical practice. Different applications in gynecology were investigated, subcategorized, and overviewed concerning surgical applications and available dyes. Specific applications in which fluorescence-guided surgery was implemented in gynecology are described in this manuscript—namely, sentinel node biopsy, mesometrium visualization, angiography of different organs, safety issues in pregnant women, ureters visualization, detection of peritoneal metastases, targeted fluorophores for cancer detection, fluorescent contamination hysterectomy, lymphography for lower limb lymphedema prevention, tumor margin detection, endometriosis, and metastases mapping. With evolving technology, further innovative research on the new applications of fluorescence visualization in cancer surgery may help to establish these techniques as standards of high-quality surgery in gynecology. However, more investigations are necessary in order to assess if these innovative tools can also be effective to improve patient outcomes and quality of life in different gynecologic malignancies.

Quantitative evaluations of vortex vein ampullae by adjusted 3D reverse projection model of ultra-widefield fundus images

The purpose of this study was to determine the number and location of vortex vein ampullae (VVA) in normal eyes. This was an observational retrospective study. Montage images of one on-axis and two off-axis ultra-widefield images of 74 healthy eyes were enhanced, and reverse projected onto a 3D model eye. The number and distance between the optic disc to each VVA in the four sectors were compared. The significance of correlations between these values and age, sex, visual acuity, refractive error, and axial length was determined. The mean number of VVA was 8.10/eye with 1.84, 2.12, 2.19 and 1.95 in upper lateral, lower lateral, upper nasal, and lower nasal sectors, respectively. The mean number of VVA/eye was significantly greater in men at 8.43 than women at 7.76 (P = 0.025). The mean distance between the optic disc and VVA was 14.15 mm, and it was 14.04, 15.55, 13.29 and 13.66 mm in the upper lateral, lower lateral, upper nasal and lower nasal sectors, respectively (all P < 0.05). The number and location of VVA can be obtained non-invasively, and the number was significantly higher in men than women. This technique can be used to determine whether these values are altered in a retinochoroidal disease.

Assessment of the choroidal structure in pregnant women in the first trimester

We investigated the anatomical differences in the choroidal structure between pregnant women in the first trimester of pregnancy and age-matched healthy nonpregnant women using enhanced depth imaging optical coherence tomography (EDI-OCT) and choroidal binarization analysis. The main parameters measured in the two study groups, namely, pregnant women in the first trimester and healthy nonpregnant women, were choroidal thickness and the choroidal luminal area. Binarization of the EDI-OCT images from each patient was performed, and the choroidal vascularity index (CVI) was calculated. The correlations between the baseline characteristics of the subjects and the CVI were investigated using linear mixed model analysis. As a result, there was no statistically significant difference in the mean age, best-corrected visual acuity, axial length, central retinal thickness, subfoveal choroidal thickness, systolic blood pressure (BP), or diastolic BP between the two study groups. Conversely, a significant difference was observed in the CVI (P = 0.012) between the two groups. The multivariate analysis identified a significant correlation between the CVI and the systolic BP (P = 0.0044, linear mixed test). Taken together, a larger choroidal luminal area was associated with a higher systolic BP, especially in the first trimester of pregnancy. Our findings may provide further insight into the choroidal changes that occur during pregnancy.

Evaluation of choroidal thickness and choroidal vascularity index during pregnancy

OBJECTIVE

To assess the choroidal structural characteristics in the first and third trimesters in pregnant women using enhanced depth imaging optical coherence tomography and binarization method.

DESIGN

Prospective study.

PARTICIPANTS

Twenty-five eyes of 25 pregnant women in the first trimester (group 1) and 25 eyes of 25 pregnant women in the third trimester (group 2) were examined. Healthy age-matched 25 participants were enrolled as a control group (group 3).

METHODS

The choroidal thickness (CT) was measured at 3 points; subfoveal, 1500 μm nasal to the fovea, and 1500 μm temporal to the fovea. Total choroidal area, luminal area, stromal area, stroma/lumen ratio, and choroidal vascularity index (CVI) were measured by Image-J software.

RESULTS

The mean subfoveal and nasal CT were statistically significantly increased in group 1 compared with controls (p = 0.005 and p = 0.004, respectively). The mean temporal CT was statistically significantly increased in group 1 compared with groups 2 and 3 (group 1 vs group 2, p = 0.043; group 1 vs group 3, p = 0.011). The mean total choroidal area, stromal area, and luminal area were significantly increased in groups 1 and 2 compared with control group (p < 0.001, p < 0.001, p < 0.001, and p < 0.001, p = 0.002, p = 0.002, respectively). There were no statistically significant differences among groups in terms of mean stroma/lumen ratio and CVI (p = 0.148 and p = 0.312, respectively).

CONCLUSIONS

There was a significant increase in subfoveal, temporal, and nasal CT in the first trimester. Total choroidal, stromal, and luminal areas were significantly increased in the first and third trimesters.

Indocyanine Green-Guided Pediatric Tumor Resection: Approach, Utility, and Challenges

Incomplete tumor resection increases the risk of local recurrence. However, the standard of care approach to distinguishing tumor tissue is less than optimal, as it depends on a conglomeration of preoperative imaging and visual and tactile indicators in real time. This approach is associated with a significant risk of inadequate resection; therefore, a novel approach that delineates the accurate intraoperative definition of pediatric tumors is urgently needed. To date, there is no reliable method for the intraoperative assessment of tumor extent and real-time differentiation between tumor- involved tissues and tumor-free tissues. Use of intraoperative frozen sections is challenging, time consuming, and covers a small surface area. Increased vascular permeability and impaired lymphatic drainage in the tumor microenvironment leads to an enhanced permeability and retention effect of small molecules. ICG is a fluorescent dye that when administered intravenously accumulates passively in the tumor because of EPR, thereby providing some tumor contrast for intraoperative real-time tumor recognition. Preclinical and clinical studies suggest that the tumor-to-background fluorescence ratio is optimized when imaging is obtained 24 h after dye injection, and many studies suggest using a high dose of ICG to optimize dye retention in the tumor tissue. However, in childhood cancers, little is known about the ideal dosing, applications, and challenges of ICG-guided tumor resection. This retrospective study examines the feasibility of ICG-guided tumor resection in common childhood solid tumors such as neuroblastoma, sarcomas, hepatic tumors, pulmonary metastases, and other rare tumors. Pediatric dosing and challenges related to the optimization of tumor-to-background ratio are also examined.

Indocyanine Green Fluorescence Versus Blue Dye or Radioisotope Regarding Detection Rate of Sentinel Lymph Node Biopsy and Nodes Removed in Breast Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Either blue dye (BD) or radioisotope (RI) is mainly used for sentinel lymph node biopsy (SLNB) in breast cancer patients. Unlike the BD, RI has lower false-negative rate of SLNB. However, its lymphoscintigraphy, difficulty in preoperative injection, and undetected sentinel lymph nodes in some cases cause surgeons to rely only on BD. Currently, indocyanine green (ICG) fluorescence method (ICG-SLNB) is increasingly used as an alternative to the conventional mapping methods in many centers. This systematic review compared ICG with the conventional method of BD or RI in terms of detection rate of SLNB and the number of sentinel lymph nodes (SLNs) removed in.

METHODS

  We searched all relevant studies published between January 2000 and October 2019. All data on for evaluation of SLN detection rate, number of SLNs removed per patient, and tumor positive rate of SLNB were extracted.

RESULTS

A total of 30 studies, including 4,216 SLN procedures were retrieved. There was a statistically significant difference between ICG and BD method in terms of SLN detection rate (OR, 6.73; 95% CI, 4.20-10.78). However, there was no significant difference between ICG and RI in this regard (OR, 0.90; 95% CI, 0.40-2.03). The number of SLNs removed per patient were 2.35 (1.46-5.4), 1.92 (1.0-3.64), and 1.72 (1.35-2.08) for ICG, BD, and RI, respectively. Only in 8 studies, the tumor positive rates in SLNB could be analyzed (ICG, 8.5-20.7%; BD, 12.7-21.4%; RI, 11.3-16%).

CONCLUSION

ICG-SLNB could be an additional or an alternative method for axillary node mapping in breast cancer.<br />.

Near-Infrared-Fluorescent Erythrocyte-Mimicking Particles: Physical and Optical Characteristics

Exogenous fluorescent materials activated by near-infrared (NIR) light can offer deep optical imaging with subcellular resolution, and enhanced image contrast. We have engineered NIR particles by doping hemoglobin-depleted erythrocyte ghosts (EGs) with indocyanine green (ICG). We refer to these optical particles as NIR erythrocyte-mimicking transducers (NETs). A particular feature of NETs is that their diameters can be tuned from micrometer to nanometer scale, thereby, providing a capability for broad NIR biomedical imaging applications. Herein, we investigate the effects of ICG concentration on key material properties of micrometer-sized NETs, and nanometer-sized NETs fabricated by either sonication or mechanical extrusion of EGs. The zeta potentials of NETs do not vary significantly with ICG concentration, suggesting that ICG is encapsulated within NETs regardless of particle size or ICG concentration. Loading efficiency of ICG into the NETs monotonically decreases with increasing values of ICG concentration. Based on quantitative analyses of the fluorescence emission spectra of the NETs, we determine that 20 μM ICG utilized during fabrication of NETs presents an optimal concentration that maximizes the integrated fluorescence emission for micrometer- and nanometer-sized NETs. Encapsulation of the ICG in these constructs also enhances the fluorescence stability and quantum yield of ICG. These results guide the engineering of NETs with maximal NIR emission for imaging applications such as fluorescence-guided tumor resection and real-time angiography.

Ocular Changes During Pregnancy

Pregnancy is needed for the perpetuation of the human species, and it leads to physiological adaptations of the various maternal organs and systems. The eye, although a closed space, also undergoes some modifications, most of which are relatively innocuous, but they may occasionally become pathological. For women, pregnancy is a susceptibility period; however, for many obstetricians, their knowledge of the ocular changes that occur during pregnancy tends to be limited. For this reason, this is a important area of study as is necessary the development of guidelines to approach those changes. Of equal importance are the knowledge of the possible therapies for ophthalmological problems in this period and the evaluation of the mode of delivery in particular conditions. For this article, an extensive review of the literature was performed, and a summary of the findings is presented.

Choroidal Thickness in Women with Uncomplicated Pregnancy: Literature Review

Pregnancy is a time when many changes occur in a woman's body. The goal of these changes is the provision of optimum conditions for the development of the foetus. Pregnancy also affects eye physiology. Well recognized physiological changes include a reduced corneal sensitivity, an increase in its central thickness and curvature, and a decrease in intraocular pressure. The association between choroidal thickness and pregnancy is not clear. Haemodynamic and hormonal changes taking place during pregnancy and the question of whether these changes are reflected by choroidal thickness are especially important. It is assumed that the choroid, which is one of the most highly vascularized tissues characterized by the highest blood flow to tissue volume ratio in the whole body, should respond by an increase in its thickness to an increase in blood flow and drop in the value of peripheral resistance. Measurement of choroidal thickness using enhanced depth imaging optical coherence tomography (EDI-OCT) in women with uncomplicated pregnancy provides important information concerning the effects of physiological changes in the eye.

Review of near-infrared methods for wound assessment

Wound management is a challenging and costly problem that is growing in importance as people are living longer. Instrumental methods are increasingly being relied upon to provide objective measures of wound assessment to help guide management. Technologies that employ near-infrared (NIR) light form a prominent contingent among the existing and emerging technologies. We review some of these technologies. Some are already established, such as indocyanine green fluorescence angiography, while we also speculate on others that have the potential to be clinically relevant to wound monitoring and assessment. These various NIR-based technologies address clinical wound management needs along the entire healing trajectory of a wound.

Evaluation of antimicrobial photodynamic therapy with indocyanine green and curcumin on human gingival fibroblast cells: An in vitro photocytotoxicity investigation

Recent investigations have suggested that antimicrobial photodynamic therapy (aPDT) can be an alternative treatment for the management of periodontal infections. However, currently there is very limited data regarding the photocytotoxicity of this method on human gingival fibroblast (HuGu) cells.

AIM

The in vitro optimal concentrations of indocyanine green (ICG) and curcumin as photosensitizers (PSs) and the irradiation time of diode laser emission were evaluated by assessing the photocytotoxicity of the treatment on HuGu cells.

MATERIALS AND METHOD

Monolayers of HuGu cells were incubated with various final concentrations of ICG (500, 750, 1000, 1250, 1500, 1750, and 2000μg/ml) and curcumin (3, 4, 5, 10, and 20mM). Three exposure times of the diode laser (30s, 60s, and 2×30s irradiation with an interval of 1min between each) and one of exposure time of 5min for LED were tested; cell viability was determined using neutral red assay. Chlorhexidine (CHX) as a gold standard antimicrobial agent for periodontal disease was considered as a control group.

RESULTS

ICG and curcumin significantly reduced HuGu cell viability at concentrations below 1000μg/ml and 10mM, respectively (P<0.01). Cytotoxicity was higher when the cells were treated for 2×30s irradiation with an interval of 1min and then again exposed to the laser for 30s (2% and 0.1%). CHX demonstrated no significant reduction in HuGu cell survival.

CONCLUSION

Photocytotoxicity is influenced by PS concentration, exposure time of PS, and time of irradiation. High doses of ICG and curcumin with lowest exposure time of light source and without cytotoxic effects may be an effective strategy for aPDT as an alternative treatment for periodontal disease.

Maternal-fetal transfer of indocyanine green across the perfused human placenta

Indocyanine green (ICG) is an FDA-approved near-infrared imaging probe, given also to pregnant women. We aimed to characterize ICG's transplacental transfer using the ex-vivo perfusion model. Placentas were obtained from caesarean deliveries. Cotyledons were cannulated and dually perfused. ICG, 9.6μg/mL and antipyrine (50μg/mL) were added to the maternal circulation in the absence (n=4) or the presence of the organic anion transporting polypeptide (OATPs) inhibitor rifampin (10μg/mL; n=5) or the P-glycoprotein inhibitor valspodar (2μg/mL; n=3). ICG's maternal-to-fetal transfer was evaluated over 180min. The cumulative percent of ICG in the fetal reservoir was minor. When ICG transfer was normalized to that of antipyrine, it was lower in the presence of rifampin (a 41% decrease; p<0.05). Valspodar did not appear to modify the kinetics of ICG. ICG's transplacental transfer is minimal and is probably OATP-mediated. The placenta is an effective protective barrier to ICG's distribution into the fetus.

Specialized Diagnostic Investigations to Assess Ocular Status in Hypertensive Diseases of Pregnancy

This review describes specialized diagnostic investigations to assess ocular status in hypertensive diseases of pregnancy. Ocular assessment can aid in early detection for prompt multidisciplinary treatment, obstetric intervention and follow-up. The investigations accurately predict the possible causes of blindness in hypertensive diseases of pregnancy. The investigations include fluorescein angiography, ophthalmodynamometry, fluorophotometry, imaging modalities, OCT, ultrasonography, doppler velocimetry and blood chemistry analysis. The review includes a summary of imaging techniques and related recent developments to assess the neuro-ophthalmic aspects of the disease. The imaging modalities have been instrumental in understanding the complex neuropathophysiological mechanisms of eclamptic seizures. The importance of blood chemistry analysis in hypertensive diseases of pregnancy has been emphasized. The investigations have made a significant contribution in improving the standards of antenatal care and reducing maternal and fetal morbidity and mortality.

Polymer-Protein Hydrogel Nanomatrix for Stabilization of Indocyanine Green towards Targeted Fluorescence and Photoacoustic Bio-imaging

Indocyanine green (ICG) is an optical contrast agent commonly used for a variety of imaging applications. However, certain limitations of the free dye molecule, concerning its low stability, uncontrolled aggregation and lack of targeting ability, have limited its use. Presented here is a method of embedding ICG in a novel polymer/protein hybrid nanocarrier so as to overcome the above inherent drawbacks of the free molecule. The hybrid nanocarrier consists of a non-toxic and biocompatible polyacrylamide nanoparticle (PAA NP) matrix that incorporates human serum albumin (HSA). This nanocarrier was synthesized through pre-conjugation with HSA and amine functionalized monomer, followed by polymerization using biodegradable cross-linkers, in a water-in-oil emulsion. The ICG dye is loaded into the HSA conjugated PAA nanoparticles (HSA-PAA NPs) through post-loading. Compared to the PAA polymer matrix, the presence of hydrophobic pockets in the HSA-PAA NPs further increases the chemical and physical stability of ICG. This is manifested by lowering the chemical degradation rates under physiological conditions, as well as by improving the thermal- and photo-stability of the dye. A targeting moiety, F3-Cys peptide, was attached to the surface of the NPs, for selective delivery to specific cancer cell lines. The suitability of these NPs for optical imaging applications was demonstrated by performing fluorescence imaging on a rat gliosarcoma cell line (9L). We also present the photoacoustic response of the HSA-PAA NPs, used as imaging contrast agents, in the spectral window of 700 nm to 800 nm.

Choroidal thickness in pregnant women measured by enhanced depth imaging optical coherence tomography

PURPOSE

To measure choroidal thickness in healthy pregnant women using enhanced depth imaging optical coherence tomography (EDI-OCT) and compare the measurements with those of healthy non-pregnant women.

METHODS

Choroidal thickness was measured at the fovea and at 3 mm superior, inferior, temporal, and nasal to the fovea using EDI-OCT in both healthy pregnant and non-pregnant women.

RESULTS

The mean choroidal thickness in pregnant women was 275 ± 84 μm at the subfoveal and 307 ± 89, 277 ± 89, 274 ± 74, and 159 ± 60 μm at 3 mm superior, inferior, temporal, and nasal to the fovea, respectively. In comparison, the mean choroidal thickness in non-pregnant women was 273 ± 92 μm at the subfoveal and 301 ± 73, 290 ± 76, 293 ± 77, and 149 ± 55 μm at 3 mm superior, inferior, temporal, and nasal to the fovea, respectively. No significant statistical differences were found for choroidal thickness between the pregnant and non-pregnant women at any of the measurement points.

CONCLUSIONS

The results of this study demonstrate that the choroidal thickness was not significantly different between healthy pregnant and non-pregnant women.

Morphologic differences, according to etiology, in pigment epithelial detachments by means of en face optical coherence tomography

PURPOSE

To assess morphologic differences in pigment epithelial detachment (PED) with en face optical coherence tomography in central serous chorioretinopathy (CSC) and age-related macular degeneration (AMD).

METHODS

We recruited 30 eyes of 22 patients with PED. Nine eyes had a clinical diagnosis of CSC and 21 had AMD. All patients were assessed with en face optical coherence tomography. Morphologic PED aspects were estimated on C-scans and classified according to shape, inner silhouette, content, wall aspects, wall thickness, and size.

RESULTS

Pigment epithelial detachment shape was predominantly circular (88.8%) in CSC and irregular or with multilobular features in AMD (76.2%). The PED inner silhouette had a smooth aspect (88.9%) in CSC and a slightly granular aspect or granular profile in AMD (100%). Clear PED content was the most characteristic feature of CSC (88.9%) but not of AMD. In CSC, PED morphologic wall aspect was uniform or slightly irregular (100%), while in AMD, it was slightly irregular (52.4%) or irregular (47.6%). Pigment epithelial detachment wall thickness and dimensions were larger in AMD than in CSC. Statistically significant differences were observed between CSC and AMD concerning PED inner silhouette, contents, wall aspects, and wall thickness measurements.

CONCLUSION

En face optical coherence tomography scanning is a valuable tool for showing important morphologic differences between CSC and AMD.

The use of dye in ophthalmology

Dyes are used in current ophthalmological practice, both as diagnostic and therapeutic aids. Commonly used dyes include sodium fluorescein, indocyanine green, rose bengal and methylene blue. The properties of these agents are outlined, along with indications for their use. The article concentrates mainly on intravenous sodium fluorescein and fundus fluorescein angiography, although topical and intracameral use of other dyes is highlighted. Ocular tissue responses are discussed, in particular those of the retinal vasculature and choroidal circulation. The normal blood-retinal barriers and pathology of abnormal angiography findings is presented. Pharmacokinetics and pharmacodynamics of intravenous dye are discussed, along with potential systemic complications.

DIGITAL SIMULTANEOUS FLUORESCEIN AND INDOCYANINE GREEN ANGIOGRAPHY, AUTOFLUORESCENCE, AND RED-FREE IMAGING WITH A SOLID-STATE LASER-BASED CONFOCAL SCANNING LASER OPHTHALMOSCOPE

PURPOSE

To describe and to evaluate a novel confocal scanning laser ophthalmoscope (cSLO) for fluorescence angiography, fundus autofluorescence (FAF), and red-free imaging.

METHODS

Digital infrared, red-free, FAF, fluorescein, and indocyanine green (ICG) angiography images were obtained with a cSLO in 766 patients. An optically pumped solid-state laser generates the excitation wavelength (488 nm) required for red-free, FAF, and fluorescein angiography images. For ICG angiography and infrared imaging, diode laser sources at 790 and 820 nm are used. Further features include an internal fixation control and a focus range of -24 to +30 diopters.

RESULTS

High-image quality is achieved with a resolution of up to 5 microm per pixel in 30- x 30-degree images and allows for accurate delineation of normal and pathologic features. Simultaneous angiography offers high-contrast images. Corresponding display of quasi-simultaneous frames facilitates interpretation. A small focus difference between fluorescein and ICG scans occurs because of chromatic aberrations. Automated alignment and generation of mean images from several single frames allow for acquisition of high-resolution FAF images.

CONCLUSION

Various laser-source related, optical, and electronic innovations improve cSLO fundus imaging for routine clinical application. A solid-state laser has advantages compared to argon gas laser sources, including less space occupation, heat emission, and noise production.

Ocular complications of pregnancy

Pregnancy is often associated with ocular changes, most often transient in nature, though occasionally permanent. It can be associated with development of new conditions, or can exacerbate pre-existing conditions. The ocular effects of pregnancy may be divided into physiologic changes, pathologic conditions or modifications of pre-existing conditions. Pathologic conditions include entities such as pre-eclampsia and eclampsia, along with conditions that are seen with increased frequency during pregnancy such as central serous retinopathy. The most significant modified pre-existing condition is diabetes mellitus. The various effects of pregnancy on the eye will be reviewed in this article.