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Journal of Biomedical Materials... Aug 2021Vitreous or vitreous humor is a complex transparent gel that fills the space between the lens and retina of an eye and acts as a transparent medium that allows light to... (Review)
Review
Vitreous or vitreous humor is a complex transparent gel that fills the space between the lens and retina of an eye and acts as a transparent medium that allows light to pass through it to reach the photoreceptor layer (retina) of the eye. The vitreous humor is removed in ocular surgery (vitrectomy) for pathologies like retinal detachment, macular hole, diabetes-related vitreous hemorrhage detachment, and ocular trauma. Since the vitreous is not actively regenerated or replenished, there is a need for a vitreous substitute to fill the vitreous cavity to provide a temporary or permanent tamponade to the retina following some vitreoretinal surgeries. An ideal vitreous substitute could probably be left inside the eye forever. The vitreous humor is transparent, biocompatible, viscoelastic and highly hydrophilic; polymeric hydrogels with these properties can be a potential candidate to be used as vitreous substitutes. To meet the tremendous demand for the vitreous substitute, many scientists all over the world have developed various kinds of vitreous substitutes or tamponade agent. Vitreous substitutes, whatsoever developed till date, are associated with several advantages and disadvantages, and there is no ideal vitreous substitute available till date. This review highlights the polymer-based vitreous substitutes developed so far, along with their advantages and limitations. The gas-based and oil-based substitutes have also been discussed but very briefly.
Topics: Biocompatible Materials; Eye Diseases; Humans; Hydrogels; Vitrectomy; Vitreous Body
PubMed: 33319466
DOI: 10.1002/jbm.b.34778 -
Investigative Ophthalmology & Visual... Dec 2023Vitreoretinal lymphoma is a high-grade malignant non-Hodgkin lymphoma with poor prognosis. The objective of this study was to elucidate the proteome profile of the...
PURPOSE
Vitreoretinal lymphoma is a high-grade malignant non-Hodgkin lymphoma with poor prognosis. The objective of this study was to elucidate the proteome profile of the vitreous in patients with vitreoretinal lymphoma (VRL), aiming to advance understanding of the pathophysiology of VRL.
METHODS
Comprehensive proteomic analyses of vitreous humor using liquid chromatography with tandem mass spectrometry were performed for 10 patients with VRL, 10 control patients with idiopathic epiretinal membrane or macular hole, and 10 patients with ocular sarcoidosis. Differentially expressed proteins (DEPs) were identified by comparing VRL with controls and sarcoidosis, and functional pathway analysis was performed. Finally, vitreous concentrations of representative DEPs that were significantly upregulated in proteomics study were measured by ELISA using a separate cohort.
RESULTS
In total, 1594 proteins were identified in the vitreous humor of VRL, control, and sarcoidosis samples. Also, 282 DEPs were detected in VRL, 249 upregulated and 33 downregulated, compared with controls. Enrichment pathway analysis showed alterations in proteasome-related pathways. Compared to controls and sarcoidosis, 14 DEPs in VRL showed significant upregulation. In the validation study, ELISA confirmed significantly higher vitreous concentrations of PSAT1, YWHAG, and 20S/26S proteasome complex in VRL compared with controls and sarcoidosis. Among the upregulated DEPs, vitreous PITHD1 and NCSTN concentrations correlated positively with vitreous IL-10 concentrations.
CONCLUSIONS
This study highlights aberrations in protein expression pattern in the vitreous of patients with VRL. The DEPs identified in this study may play pivotal roles in VRL pathogenesis, providing insights to enhance understanding of VRL pathophysiology and contribute to the development of VRL biomarkers.
Topics: Humans; Vitreous Body; Retinal Neoplasms; Proteomics; Lymphoma, Non-Hodgkin; Sarcoidosis; Proteins; 14-3-3 Proteins
PubMed: 38038618
DOI: 10.1167/iovs.64.15.2 -
Journal of Analytical Toxicology Feb 2021Vitreous humor is a potential alternative matrix for postmortem toxicology drug screens when peripheral blood is unavailable. It is easily and reliably collected and may...
Vitreous humor is a potential alternative matrix for postmortem toxicology drug screens when peripheral blood is unavailable. It is easily and reliably collected and may not suffer from the same postmortem redistribution as seen in blood. Here, we compared the concentrations of 7 acidic drugs (acetaminophen, ibuprofen, naproxen, salicylic acid, carbamazepine, phenobarbital and phenytoin) in peripheral blood and vitreous fluid collected in 89 autopsy cases. Analysis was done by high-performance liquid chromatography with diode-array detection. Overall, we found that vitreous drug concentrations were significantly lower than peripheral blood with median vitreous to peripheral blood (V/PB) ratios ranging from 0.0 to 0.6 (mean, 0.1-0.6). The correlations between the concentrations of over-the-counter analgesics in peripheral blood versus vitreous fluid were poor, with acetaminophen exhibiting the best linearity (R2 = 0.72). The antiepileptic drugs (carbamazepine, phenytoin and phenobarbital) exhibited good correlations between peripheral blood and vitreous humor, with all exhibiting an R2 ≥ 0.95. Overall, we have demonstrated the potential of vitreous fluid as an alternative matrix for the detection of select acidic drugs.
Topics: Autopsy; Benzodiazepines; Body Fluids; Forensic Toxicology; Humans; Pharmaceutical Preparations; Postmortem Changes; Substance Abuse Detection; Vitreous Body
PubMed: 31696920
DOI: 10.1093/jat/bkz076 -
Experimental Eye Research Jun 2020The complement system may be activated in the posterior segment of the eye with chorioretinal disease, which may be reflected to the concentration of anaphylatoxins in... (Review)
Review
The complement system may be activated in the posterior segment of the eye with chorioretinal disease, which may be reflected to the concentration of anaphylatoxins in the aqueous humor. Little is known about the distribution of anaphylatoxins in the aqueous and vitreous humor. The aim of the present study was to investigate the distribution of anaphylatoxin concentration in the aqueous and vitreous humor of the eyes with idiopathic epiretinal membrane or idiopathic macular hole. This was an experimental, observational case series. This study included 43 eyes from 43 patients; 29 eyes with idiopathic epiretinal membrane, and 14 eyes with idiopathic macular hole. All 43 eyes underwent cataract surgery and vitrectomy. The aqueous and vitreous humor were collected at the surgery. The anaphylatoxin concentrations were measured by using a cytometric beads array, and the respective C3a, C4a, and C5a concentrations were 2.003 ± 0.679 (mean ± standard deviation) ng/ml, 1.389 ± 0.419 ng/ml, and 0.003 ± 0.004 ng/ml in the aqueous humor, and 1.236 ± 0.642 ng/ml, 1.250 ± 0.542 ng/ml, and 0.048 ± 0.069 ng/ml in the vitreous humor. The mean C3a concentration in the aqueous humor was significantly higher than in the vitreous humor in 43 eyes of iMH and iERM (P < 0.001). The mean C4a concentration showed no significant difference between the aqueous humor and vitreous humor (P = 0.282), and the mean C5a in the aqueous humor was significantly lower than in the vitreous humor overall (P < 0.001). The C3a concentration in the aqueous humor strongly correlated with that in the vitreous humor (R = 0.510, P < 0.001). The concentrations of C4a and C5a in the aqueous humor moderately correlated with those in the vitreous humor (C4a; R = 0.356, P = 0.019, C5a; R = 0.464, P = 0.022). In conclusion, the anaphylatoxin concentrations measured by cytometric beads array in the aqueous humor may be associated with those measured in the vitreous humor.
Topics: Anaphylatoxins; Aqueous Humor; Humans; Retinal Degeneration; Vitreous Body
PubMed: 32224205
DOI: 10.1016/j.exer.2020.108025 -
Current Eye Research Apr 2021Research on the vitreous humor and development of hydrogel vitreous substitutes have gained a rapid increase in interest within the past two decades. However, the... (Review)
Review
Research on the vitreous humor and development of hydrogel vitreous substitutes have gained a rapid increase in interest within the past two decades. However, the properties of the vitreous humor and vitreous substitutes have yet to be consolidated. In this paper, the mechanical properties of the vitreous humor and hydrogel vitreous substitutes were systematically reviewed. The number of publications on the vitreous humor and vitreous substitutes over the years, as well as their respective testing conditions and testing techniques were analyzed. The mechanical properties of the human vitreous were found to be most similar to the vitreous of pigs and rabbits. The storage and loss moduli of the hydrogel vitreous substitutes developed were found to be orders of magnitude higher in comparison to the native human vitreous. However, the reported modulus for human vitreous, which was most commonly tested , has been hypothesized to be different . Future studies should focus on testing the mechanical properties of the vitreous or . In addition to its mechanical properties, the vitreous humor has other biotransport mechanisms and biochemical functions that establish a redox balance and maintain an oxygen gradient inside the vitreous chamber to protect intraocular tissues from oxidative damage. Biomimetic hydrogel vitreous substitutes have the potential to provide ophthalmologists with additional avenues for treating and controlling vitreoretinal diseases while preventing complications after vitrectomy. Due to the proximity and interconnectedness of the vitreous humor to other ocular tissues, particularly the lens and the retina, more interest has been placed on understanding the properties of the vitreous humor in recent years. A better understanding of the properties of the vitreous humor will aid in improving the design of biomimetic vitreous substitutes and enhancing intravitreal biotransport.
Topics: Biocompatible Materials; Biological Transport; Biomechanical Phenomena; Biomimetic Materials; Humans; Hydrogels; Viscoelastic Substances; Vitreous Body
PubMed: 33040616
DOI: 10.1080/02713683.2020.1826977 -
Cellular and Molecular Life Sciences :... Dec 2022Proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), and neovascular age-related macular degeneration (nAMD) are among the leading causes of... (Review)
Review
Proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), and neovascular age-related macular degeneration (nAMD) are among the leading causes of blindness. Due to the multifactorial nature of these vitreoretinal diseases, omics approaches are essential for a deeper understanding of the pathophysiologic processes underlying the evolution to a proliferative or neovascular etiology, in which patients suffer from an abrupt loss of vision. For many years, it was thought that the function of the vitreous was merely structural, supporting and protecting the surrounding ocular tissues. Proteomics studies proved that vitreous is more complex and biologically active than initially thought, and its changes reflect the physiological and pathological state of the eye. The vitreous is the scenario of a complex interplay between inflammation, fibrosis, oxidative stress, neurodegeneration, and extracellular matrix remodeling. Vitreous proteome not only reflects the pathological events that occur in the retina, but the changes in the vitreous itself play a central role in the onset and progression of vitreoretinal diseases. Therefore, this review offers an overview of the studies on the vitreous proteome that could help to elucidate some of the pathological mechanisms underlying proliferative and/or neovascular vitreoretinal diseases and to find new potential pharmaceutical targets.
Topics: Humans; Vitreous Body; Proteome; Vitreoretinopathy, Proliferative; Retina; Diabetic Retinopathy
PubMed: 36585968
DOI: 10.1007/s00018-022-04670-y -
Journal of Controlled Release :... Jan 2021Age-related macular degeneration (AMD) is the third leading cause worldwide blindness that causes permanent central vision impairment in older people. Over the past few... (Review)
Review
Age-related macular degeneration (AMD) is the third leading cause worldwide blindness that causes permanent central vision impairment in older people. Over the past few years, there has been significant progress in the diagnosis and therapy of AMD. Currently available diagnostic and therapeutic strategies are clinically limited to manage AMD. The intravitreal (IVT) injection therapy has its shortcomings due to the ocular barriers and frequent administration of drugs into the vitreous humor of the eye. The safe and effective formulations will address the unmet medical needs of AMD. Various engineered nanoformulations, composed of polymers, lipids, proteins, inorganic materials, have been significantly investigated for the management of AMD over the past decade. The purpose of the review was to provide a comprehensive overview of the current state-of-the-art clinical diagnosis and treatment modalities for AMD. This review highlights the progress and future perspectives of nanodiagnostics and nanotherapeutics.
Topics: Aged; Humans; Macular Degeneration; Vitreous Body
PubMed: 33129920
DOI: 10.1016/j.jconrel.2020.10.054 -
Journal of Analytical Toxicology Apr 2020Gamma-hydroxybutyrate (GHB) is a naturally occurring molecule present in the human body as a catabolite of the neurotransmitter gamma-aminobutyrate (GABA). In the USA,...
Gamma-hydroxybutyrate (GHB) is a naturally occurring molecule present in the human body as a catabolite of the neurotransmitter gamma-aminobutyrate (GABA). In the USA, GHB has a history of being manufactured illicitly and abused, with misguided proposed benefits for the body-building community and a persistent party drug with reported GHB overdoses occurring worldwide. The interpretation of GHB in postmortem biological fluids is complicated by the endogenous nature of the molecule. Analysis often requires more than one biological matrix to detect exogenous exposure, typically in urine. The analysis is further complicated by the endogenous de novo production of GHB in postmortem specimens. This work sought to examine the prevalence of endogenous GHB concentrations in postmortem toxicology samples from Orange County, CA, and to establish suitable in-house secondary matrices to confirm or rule out exogenous GHB exposure. A total of 348 postmortem heart blood samples were randomly selected and analyzed for GHB using liquid-liquid extraction followed by gas chromatography-mass spectrometry with selective ion monitoring and GHB-d6 as an internal standard. Of the 348 cases analyzed, 39 cases resulted in positive GHB detection with the median concentration of 22.45 mg/L (10.4-62.16 mg/L). None of the positive samples had suspected GHB ingestion or usage from the case report. GHB concentrations were then examined in secondary matrices collected at autopsy from the positive cases that included (when available) peripheral blood, urine, vitreous humor, liver homogenate and brain homogenate. Within the secondary matrices, GHB levels in peripheral blood compared to that of heart blood, while liver homogenate levels were variable. Quantifiable GHB levels were not identified in vitreous humor and brain homogenate samples. Our findings reaffirm the importance of multi-matrix analysis in postmortem toxicology and further confirm the utility of vitreous humor and brain tissue to distinguish exogenous GHB exposure from endogenous production.
Topics: Autopsy; Body Fluids; Humans; Illicit Drugs; Postmortem Changes; Sodium Oxybate; Substance Abuse Detection; Vitreous Body
PubMed: 31776561
DOI: 10.1093/jat/bkz094 -
Journal of Forensic and Legal Medicine Oct 2021Vitreous humor has been extensively used in forensic practice to assess hyperglycemia after death. The results from different articles, for various hyperglycemia markers... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Vitreous humor has been extensively used in forensic practice to assess hyperglycemia after death. The results from different articles, for various hyperglycemia markers are highly variable, and a systematic analysis of the results from studies currently used in forensic practice as landmarks has not yet been performed. Therefore, we aimed to evaluate to usefulness and limits of using the values of vitreous glucose, lactic acid, beta-hydroxybutyrate, and 1,5 Anhydro-d-glucitol to detect postmortem hyperglycemia.
MATERIALS AND METHODS
For this purpose, we performed a systematic review and a meta-analysis using the random-effects model to identify the threshold values and average differences for the markers mentioned above in the vitreous humor of diabetic versus nondiabetic subjects.
RESULTS
We included eleven studies in the meta-analysis and found the following mean differences between the diabetic and nondiabetic groups: for glucose - 91.4 mg/dl, for lactate - 34.17 mg/dl, for the Traub formula - 111 mg/dl, for fructosamine - 0.71 mmol/L, for beta-hydroxybutyrate - 36.55 mg/dl and 1,5 Anhydro-d-glucitol - -15.2 mg/dl. We also gave practical recommendations, based on the range of values and 95% confidence intervals in normal subjects and controls to identify antemortem hyperglycemia and evaluated, whenever possible, threshold values for fatal diabetes.
CONCLUSIONS
Glucose, Traub formula, fructosamine, and beta-hydroxy-butyrate can be used to detect postmortem hyperglycemia with some limitations; 1,5 Anhydro-d-glucitol can only be used to suggest the absence of a hyperglycemic status before death.
Topics: 3-Hydroxybutyric Acid; Biomarkers; Deoxyglucose; Forensic Medicine; Fructosamine; Glucose; Humans; Hyperglycemia; Lactic Acid; Postmortem Changes; Vitreous Body
PubMed: 34488176
DOI: 10.1016/j.jflm.2021.102250 -
Forensic Science International May 2020The chemical and biochemical analysis of bodily fluids after death is an important thanatochemical approach to assess the cause and time since death. Vitreous humor (VH)... (Review)
Review
The chemical and biochemical analysis of bodily fluids after death is an important thanatochemical approach to assess the cause and time since death. Vitreous humor (VH) has been used as a biofluid for forensic purposes since the 1960s. Due to its established relevance in toxicology, a literature review highlighting the use of VH with an emphasis on endogenous compounds has not yet been undertaken. VH is a chemically complex aqueous solution of carbohydrates, proteins, electrolytes and other small molecules present in living organisms; this biofluid is useful tool for its isolated environment, preserved from bacterial contamination, decomposition, autolysis, and metabolic reactions. The post-mortem analysis of VH provides an important tool for the estimation of the post-mortem interval (PMI), which can be helpful in determining the cause of death. Consequently, the present review evaluates the recent chemical and biochemical advances with particular importance on the endogenous compounds present at the time of death and their modification over time, which are valuable for the PMI prediction and to identify the cause of death.
Topics: Autopsy; Forensic Pathology; Humans; Illicit Drugs; Postmortem Changes; Vitreous Body
PubMed: 32169668
DOI: 10.1016/j.forsciint.2020.110235