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Clinical & Experimental Optometry May 2018
Topics: Conjunctiva; Conjunctival Diseases; Diagnosis, Differential; Female; Humans; Lymphangiectasis; Slit Lamp Microscopy; Tomography, Optical Coherence; Young Adult
PubMed: 29232763
DOI: 10.1111/cxo.12647 -
Survey of Ophthalmology 2022There are currently no effective methods to prevent or durably treat ocular symblephara, the adhesions between the palpebral and bulbar conjunctiva. How symblephara form... (Review)
Review
There are currently no effective methods to prevent or durably treat ocular symblephara, the adhesions between the palpebral and bulbar conjunctiva. How symblephara form at the molecular level is largely unknown. We present here an overview of current clinical symblephara treatments and describe potential molecular mechanisms behind conjunctival adhesion formation that may inform future symblephara treatment and prevention options. Understanding how symblephara form at the molecular level will facilitate treatment development. Preventative therapies may be possible by targeting symblephara progenitor cells immediately after injuries, while novel therapeutics should be aimed at modulating TGF-β pathways and effector cells in conjunctival scarring to treat symblephara formation more effectively.
Topics: Conjunctiva; Conjunctival Diseases; Eyelid Diseases; Humans; Stem Cells
PubMed: 33932469
DOI: 10.1016/j.survophthal.2021.04.008 -
The Anatomical Record May 1996Epithelial proliferation is linked with cell displacement. When a cell divides, one of its progeny replaces the dividing ancestor and the other is displaced into a more...
BACKGROUND
Epithelial proliferation is linked with cell displacement. When a cell divides, one of its progeny replaces the dividing ancestor and the other is displaced into a more remote location that has to be vacated first by peripheral cells. As cells are neither pushed nor pulled in a mechanical sense, and since they do not move by their own means, this displacement is best regarded as streaming. The purpose of the present study was to measure epithelial cell streaming in adult rat conjunctiva.
METHODS
Twenty-seven female adult rats were injected i.p. with 18.5 KBq [3H]-thymidine/g body weight, specific activity 185 GBq/mMol. Three rats were killed at different times up to 28 d. Eyes and eyelids were removed in one piece, cut along the pupillary-optic nerve line into 5-microns-thick sections, and prepared for autoradiography. In each eye, the entire upper conjunctiva extending from limbus to the palpebral muco-cutaneous junction was scanned with an ocular micrometer grid. The limbus served as point of origin. The x, y coordinate of each nucleus with two grains or more and its grain content were recorded.
RESULTS
One hour after labeling, labeled cells were spread evenly along the basal layer. Cells of the upper layers were not labeled. As time passed by, labeled cells in the fornix became more abundant, while in the limbus and palpebral margin, their frequency declined. Labeled cells streamed from the limbus and palpebral muco-cutaneous junction to the fornix. Bulbar conjunctival epithelia streamed at a velocity of 13.2 microns/day. Epithelia in the palpebral conjunctiva streamed at a velocity of 11.8 microns/day. At the same time cells streamed from the basal layer to the epithelial surface at a velocity of 0.4 microns/day. Generation time was 3.9 days.
CONCLUSIONS
Bulbar and palpebral conjunctivae are two independent cell kinetic systems that originate in two stem cell regions, one in the limbus and the other in the muco-cutaneous junction. Each system is made of two compartments, a progenitor where cells proliferate, and a compartment of non proliferating end cells. Progenitors created in the first, enter the second and turn into end cells. Ultimately they die in the fornix. The undetermined limbus stem cell generates two epithelial cell lines, a corneal and a conjunctival.
Topics: Animals; Cell Movement; Conjunctiva; Epithelium; Female; Mitosis; Rats; Regression Analysis; Stem Cells; Time Factors
PubMed: 8731037
DOI: 10.1002/(SICI)1097-0185(199605)245:1<36::AID-AR6>3.0.CO;2-D -
Ophthalmic Research 2022Pterygium is a kind of common conjunctival degeneration. The pathogenesis of pterygium is complex, and various biomarkers provide new targets for treatment and... (Review)
Review
Pterygium is a kind of common conjunctival degeneration. The pathogenesis of pterygium is complex, and various biomarkers provide new targets for treatment and prognosis. Currently, the most common treatment for pterygium is surgical excision, but it is invasive risk and has a high recurrence rate. Since the development of sequencing, gene chip technology, and proteomics technologies has been rapid, research on the internal mechanism of disease has been facilitated. This review focuses on recent advances in the discovery of biomarkers from the fields of genetics, proteomics, and epigenetics and their likely functional mechanisms and clinical applications in pterygium.
Topics: Biomarkers; Conjunctiva; Follow-Up Studies; Humans; Pterygium; Recurrence; Transplantation, Autologous
PubMed: 35405677
DOI: 10.1159/000523878 -
Cell Stem Cell Feb 2024The conjunctival epithelium covering the eye contains two main cell types: mucus-producing goblet cells and water-secreting keratinocytes, which present mucins on their...
The conjunctival epithelium covering the eye contains two main cell types: mucus-producing goblet cells and water-secreting keratinocytes, which present mucins on their apical surface. Here, we describe long-term expanding organoids and air-liquid interface representing mouse and human conjunctiva. A single-cell RNA expression atlas of primary and cultured human conjunctiva reveals that keratinocytes express multiple antimicrobial peptides and identifies conjunctival tuft cells. IL-4/-13 exposure increases goblet and tuft cell differentiation and drastically modifies the conjunctiva secretome. Human NGFR+ basal cells are identified as bipotent conjunctiva stem cells. Conjunctival cultures can be infected by herpes simplex virus 1 (HSV1), human adenovirus 8 (hAdV8), and SARS-CoV-2. HSV1 infection was reversed by acyclovir addition, whereas hAdV8 infection, which lacks an approved drug therapy, was inhibited by cidofovir. We document transcriptional programs induced by HSV1 and hAdV8. Finally, conjunctival organoids can be transplanted. Together, human conjunctiva organoid cultures enable the study of conjunctival (patho)-physiology.
Topics: Humans; Mice; Animals; Conjunctiva; Goblet Cells; Epithelium; Interleukin-13; Homeostasis; Organoids
PubMed: 38215738
DOI: 10.1016/j.stem.2023.12.008 -
Arquivos Brasileiros de Oftalmologia 2020The aim of the present study was to measure the free carnitine and acylcarnitine levels in pterygium tissue and normal conjunctival tissue at the metabolomics level...
PURPOSE
The aim of the present study was to measure the free carnitine and acylcarnitine levels in pterygium tissue and normal conjunctival tissue at the metabolomics level using tandem mass spectrometry.
METHODS
In this prospective, clinical randomized study, pterygium tissues and normal conjunctival tissues taken during pterygium excision with autograft were compared regarding their free carnitine and acylcarnitine profiles. After tissue homogenization, carnitine levels were measured using tandem mass spectrometry. The data were statistically analyzed with the Wilcoxon signed-rank test.
RESULTS
Pterygium and normal conjunctival tissue samples from a single eye of 29 patients (16 females, 13 males; mean age, 54.75 ± 11.25 years [range, 21-78 years]) were evaluated. While the free carnitine (C0) level was significantly high in the pterygium tissue (p<0.001), acylcarnitine levels were significantly high in some esterized derivatives (C2, C5, C5:1, C5DC, C16:1, C18, methylglutarylcarnitine) (p<0.05). No statistically significant difference was determined for the other esterized derivatives (p>0.05).
CONCLUSION
That the carnitine levels in pterygium tissue were higher suggests that acceleration of cell metabolism developed secondary to chronic inflammation and the premalignant characteristics of pterygium tissue. High carnitine levels may also effectively suppress the apoptosis process. The data reported in our study indicate that further, more extensive studies of the carnitine profile could help clarify the pathogenesis of pterygium.
Topics: Adult; Aged; Carnitine; Conjunctiva; Female; Humans; Male; Metabolomics; Middle Aged; Prospective Studies; Pterygium; Tandem Mass Spectrometry; Young Adult
PubMed: 31531547
DOI: 10.5935/0004-2749.20200001 -
Scientific Reports Mar 2018Conjunctivochalasis is a common cause of tear dysfunction due to the conjunctiva becoming loose and wrinkly with age. The current solutions to this disease include...
Conjunctivochalasis is a common cause of tear dysfunction due to the conjunctiva becoming loose and wrinkly with age. The current solutions to this disease include either surgical excision in the operating room, or thermoreduction of the loose tissue with hot wire in the clinic. We developed a near-infrared laser thermal conjunctivoplasty system. The system utilizes a 1460-nm programmable laser diode system as the light source. At this wavelength, a water absorption peak exists and the blood absorption is minimal, so the heating of redundant conjunctiva is even and there is no bleeding. A miniaturized handheld probe delivers the laser light and reshapes the laser into a 10 × 1 mm line on the working plane. A foot pedal is used to deliver a preset number of calibrated laser pulses. A fold of loose conjunctiva is grasped by a pair of forceps. The NIR laser light is delivered through an optical fiber and a laser line is aimed exactly on the conjunctival fold by a cylindrical lens. Ex vivo experiments using porcine eye was performed to investigate the induced shrinkage of conjunctiva and decide the optimal laser parameters. It was found that up to 45% of conjunctiva shrinkage could be achieved.
Topics: Animals; Conjunctiva; Conjunctival Diseases; Eye; Laser Therapy; Light; Ophthalmologic Surgical Procedures; Swine
PubMed: 29497112
DOI: 10.1038/s41598-018-22204-0 -
The Indian Journal of Medical Research Nov 2020
Topics: Child; Conjunctiva; Developmental Disabilities; Humans; Vascular Diseases; Veins
PubMed: 35345148
DOI: 10.4103/ijmr.IJMR_2167_19 -
Experimental Eye Research Dec 2020Most patients with chronic dry eye disease (DED) have episodic flares, which can be triggered by a variety of activities and environmental stresses. These flares are... (Review)
Review
Most patients with chronic dry eye disease (DED) have episodic flares, which can be triggered by a variety of activities and environmental stresses. These flares are typically associated with rapid exacerbation of discomfort symptoms, followed by prolonged elevation of inflammation. In an acute flare, ocular surface inflammation begins with a nonspecific innate immune response, in some cases followed by a slower but more specific adaptive immune response. At the ocular surface, epithelial cells are central to the innate immune response, and we discuss their role in DED flares alongside the other core components. Epithelial cells and other cells of the innate response (neutrophils, monocytes, macrophages and dendritic cells) trigger flares in response to increased osmolarity, detected via pattern receptors on their cell surface. Ultimately, downstream signaling pathways activate innate and adaptive immune responses, with consequent inflammation and symptoms. In chronic DED, pathogenic T cells have infiltrated the ocular surface tissues. The established adaptive immune response is likely to lead to flare-ups at lower thresholds of stress, with inflammation maintained over a longer period. Increased understanding of the inflammatory cascades activated during a flare may guide management and improve outcomes.
Topics: Conjunctiva; Cytokines; Dry Eye Syndromes; Humans; Immunity, Innate; Inflammation; T-Lymphocytes
PubMed: 33039458
DOI: 10.1016/j.exer.2020.108294 -
Ophthalmic Surgery, Lasers & Imaging... May 2022To describe conjunctiva and Tenon's capsule handling during the Port Delivery System with ranibizumab (PDS) implant insertion procedure including up-front assessments,...
OBJECTIVES
To describe conjunctiva and Tenon's capsule handling during the Port Delivery System with ranibizumab (PDS) implant insertion procedure including up-front assessments, planning, and instrumentation, with emphasis placed on the peritomy, scleral dissection, and closure steps.
METHODS
Surgical pearls based on experience accumulated in the PDS clinical trial program in patients with retinal diseases.
RESULTS
Preoperative preparation, specific instruments, and meticulous techniques are key to optimizing surgical outcomes. Before surgery, assessment of factors that affect conjunctival integrity and an in-office conjunctiva examination are conducted. Gentle, purposeful conjunctiva and Tenon's capsule handling with nontoothed forceps and suturing with a BV needle are recommended to prevent tissue damage. The peritomy is 6 mm by 6 mm, centered around the planned implant location in the superotemporal quadrant. A complete sub-Tenon's capsule dissection is achieved using a wide, robust lateral and posterior dissection technique to free tissue from the sclera and minimize tension. The globe is stabilized during scleral cutdown by grasping the sclera with fine-toothed forceps away from the incision edge to prevent tissue delamination. When closing the peritomy, both the conjunctiva and Tenon's capsule are completely captured and sutured with scleral anchoring at the apex of the peritomy to help prevent conjunctival retraction and erosion. Mitigation and detection of adverse events is critical to successful surgical outcomes.
CONCLUSIONS
The PDS implant insertion procedure is straightforward, but it requires planned preoperative preparation, specific instruments, and meticulous techniques. The surgical pearls described here offer insights for optimizing outcomes. .
Topics: Conjunctiva; Humans; Ranibizumab; Sclera; Surgical Flaps; Tenon Capsule
PubMed: 35575739
DOI: 10.3928/23258160-20220415-03