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Duct system of the rabbit lacrimal gland: structural characteristics and role in lacrimal secretion.Investigative Ophthalmology & Visual... Jun 2010To develop a nomenclature for the lacrimal duct system in the rabbit, based on the anatomic and structural characteristics of each duct segment, and to provide RT-PCR...
PURPOSE
To develop a nomenclature for the lacrimal duct system in the rabbit, based on the anatomic and structural characteristics of each duct segment, and to provide RT-PCR and immunofluorescence data to support the notion that the duct system plays important roles in lacrimal function.
METHODS
Paraffin-embedded lacrimal glands (LGs) were stained with hematoxylin and eosin (H&E) and evaluated with a stereomicroscope. Cryosections of LG were stained with cresyl violet, and acinar cells and ductal epithelial cells were isolated from each duct segment by laser capture microdissection (LCM). mRNA levels from these cells were analyzed by real-time RT-PCR. Standard protocol was followed for immunofluorescence detection of ionic transporters.
RESULTS
The lacrimal duct system was divided into six segments on the basis of morphologic characteristics: the intercalated, intralobular, interlobular, intralobar, interlobar, and main excretory ducts. Although the morphologic features change incrementally along the entire duct system, the gene expression of ionic transporters and aquaporins, including AE3, AQP4, AQP5, CFTR, ClC2gamma, KCC1, NHE1, NKAalpha1, NKAbeta1, NKAbeta2, NKAbeta3, and NKCC1 varied greatly among duct segments. Immunofluorescence results were generally in accordance with the abundance of mRNAs along the acinus-duct axis.
CONCLUSIONS
Most LG research has focused on the acinar cells, with relatively little attention being paid to the lacrimal ducts. The lack of knowledge regarding the lacrimal ducts was so profound that a precise nomenclature had not been established for the duct system. The present data establish a nomenclature for each segment of the lacrimal duct system and provide evidence that ducts play critical roles in lacrimal secretion.
Topics: Animals; Aquaporins; Epithelial Cells; Female; Fluorescent Antibody Technique, Indirect; Ion Transport; Lacrimal Apparatus; RNA, Messenger; Rabbits; Reverse Transcriptase Polymerase Chain Reaction; Tears; Terminology as Topic
PubMed: 20107177
DOI: 10.1167/iovs.09-4687 -
Scientific Reports Sep 2018Woundhealing disorders characterized by impaired or delayed re-epithelialization are a serious medical problem that is painful and difficult to treat. Gelsolin (GSN), a...
Woundhealing disorders characterized by impaired or delayed re-epithelialization are a serious medical problem that is painful and difficult to treat. Gelsolin (GSN), a known actin modulator, supports epithelial cell regeneration and apoptosis. The aim of this study was to estimate the potential of recombinant gelsolin (rhu-pGSN) for ocular surface regeneration to establish a novel therapy for delayed or complicated wound healing. We analyzed the influence of gelsolin on cell proliferation and wound healing in vitro, in vivo/ex vivo and by gene knockdown. Gelsolin is expressed in all tested tissues of the ocular system as shown by molecular analysis. The concentration of GSN is significantly increased in tear fluid samples of patients with dry eye disease. rhu-pGSN induces cell proliferation and faster wound healing in vitro as well as in vivo/ex vivo. TGF-β dependent transcription of SMA is significantly decreased after GSN gene knockdown. Gelsolin is an inherent protein of the ocular system and is secreted into the tear fluid. Our results show a positive effect on corneal cell proliferation and wound healing. Furthermore, GSN regulates the synthesis of SMA in myofibroblasts, which establishes GSN as a key protein of TGF-β dependent cell differentiation.
Topics: Actins; Animals; Cell Differentiation; Cell Proliferation; Conjunctiva; Cornea; Dry Eye Syndromes; Epithelial Cells; Eyelids; Female; Gelsolin; Gene Expression Regulation; Humans; Lacrimal Apparatus; Male; Mice; Myofibroblasts; Nasolacrimal Duct; RNA, Small Interfering; Re-Epithelialization; Signal Transduction; Transforming Growth Factor beta; Wound Healing
PubMed: 30177722
DOI: 10.1038/s41598-018-31441-2 -
Progress in Retinal and Eye Research May 2009The lacrimal gland is the major contributor to the aqueous layer of the tear film which consists of water, electrolytes and proteins. The amount and composition of this... (Review)
Review
The lacrimal gland is the major contributor to the aqueous layer of the tear film which consists of water, electrolytes and proteins. The amount and composition of this layer is critical for the health, maintenance, and protection of the cells of the cornea and conjunctiva (the ocular surface). Small changes in the concentration of tear electrolytes have been correlated with dry eye syndrome. While the mechanisms of secretion of water, electrolytes and proteins from the lacrimal gland differ, all three are under tight neural control. This allows for a rapid response to meet the needs of the cells of the ocular surface in response to environmental conditions. The neural response consists of the activation of the afferent sensory nerves in the cornea and conjunctiva to stimulate efferent parasympathetic and sympathetic nerves that innervate the lacrimal gland. Neurotransmitters are released from the stimulated parasympathetic and sympathetic nerves that cause secretion of water, electrolytes, and proteins from the lacrimal gland and onto the ocular surface. This review focuses on the neural regulation of lacrimal gland secretion under normal and dry eye conditions.
Topics: Animals; Dry Eye Syndromes; Humans; Lacrimal Apparatus; Neurons, Afferent; Neurons, Efferent; Neurotransmitter Agents; Signal Transduction; Tears; Water-Electrolyte Balance
PubMed: 19376264
DOI: 10.1016/j.preteyeres.2009.04.003 -
Journal of Neural Engineering Feb 2016To study electrical stimulation of the lacrimal gland and afferent nerves for enhanced tear secretion, as a potential treatment for dry eye disease. We investigate the...
OBJECTIVE
To study electrical stimulation of the lacrimal gland and afferent nerves for enhanced tear secretion, as a potential treatment for dry eye disease. We investigate the response pathways and electrical parameters to safely maximize tear secretion.
APPROACH
We evaluated the tear response to electrical stimulation of the lacrimal gland and afferent nerves in isofluorane-anesthetized rabbits. In acute studies, electrical stimulation was performed using bipolar platinum foil electrodes, implanted beneath the inferior lacrimal gland, and a monopolar electrode placed near the afferent ethmoid nerve. Wireless microstimulators with bipolar electrodes were implanted beneath the lacrimal gland for chronic studies. To identify the response pathways, we applied various pharmacological inhibitors. To optimize the stimulus, we measured tear secretion rate (Schirmer test) as a function of pulse amplitude (1.5-12 mA), duration (0.1-1 ms) and repetition rate (10-100 Hz).
MAIN RESULTS
Stimulation of the lacrimal gland increased tear secretion by engaging efferent parasympathetic nerves. Tearing increased with stimulation amplitude, pulse duration and repetition rate, up to 70 Hz. Stimulation with 3 mA, 500 μs pulses at 70 Hz provided a 4.5 mm (125%) increase in Schirmer score. Modulating duty cycle further increased tearing up to 57%, compared to continuous stimulation in chronically implanted animals (36%). Ethmoid (afferent) nerve stimulation increased tearing similar to gland stimulation (3.6 mm) via a reflex pathway. In animals with chronically implanted stimulators, a nearly 6 mm increase (57%) was achieved with 12-fold less charge density per pulse (0.06-0.3 μC mm(-2) with 170-680 μs pulses) than the damage threshold (3.5 μC mm(-2) with 1 ms pulses).
SIGNIFICANCE
Electrical stimulation of the lacrimal gland or afferent nerves may be used as a treatment for dry eye disease. Clinical trials should validate this approach in patients with aqueous tear deficiency, and further optimize electrical parameters for maximum clinical efficacy.
Topics: Afferent Pathways; Animals; Dry Eye Syndromes; Electric Stimulation Therapy; Eye Injuries; Lacrimal Apparatus; Peripheral Nerves; Rabbits; Tears; Treatment Outcome
PubMed: 26655141
DOI: 10.1088/1741-2560/13/1/016006 -
Korean Journal of Ophthalmology : KJO Jun 2023A systematic review of the literature on diagnostic and therapeutic indications, techniques, and complications of dacryoendoscopy (DE) was performed.
PURPOSE
A systematic review of the literature on diagnostic and therapeutic indications, techniques, and complications of dacryoendoscopy (DE) was performed.
METHODS
The authors performed a PubMed search of articles published in English on DE. Data were collected and classified according to the categories of the disease. The clinical outcomes and limitations were particularly analyzed.
RESULTS
The lacrimal drainage system from the canaliculus to the inferior meatus could be examined based on the specific anatomical features by DE. The canalicular mucosa is smooth and brightly colored, the lacrimal sac shows covering mucosa with good vascularization and the nasolacrimal duct is lined with bright tubular mucosal folds. DE allows direct visualization of the detailed internal condition of the lacrimal disorders, to directly diagnose the site of obstruction with accuracy and address the causes and recanalize the lacrimal drainage system using assisted micro lacrimal surgical instruments in the tearing patients.
CONCLUSIONS
Better visualization of the lacrimal canal with DE improves the understanding of physiology and precise identification of the obstructing lesions, both of which are the key to a comprehensive management for the tearing patients.
Topics: Humans; Dacryocystorhinostomy; Lacrimal Apparatus Diseases; Nasolacrimal Duct; Lacrimal Apparatus; Tears; Lacerations; Lacrimal Duct Obstruction
PubMed: 37068832
DOI: 10.3341/kjo.2023.0014 -
European Journal of Ophthalmology May 2023Endoscopic (END-DCR) and external dacryocystorhinostomies (EXT-DCR) are nowadays considered the gold standard techniques for non-oncologic distal acquired lacrimal... (Review)
Review
Endoscopic (END-DCR) and external dacryocystorhinostomies (EXT-DCR) are nowadays considered the gold standard techniques for non-oncologic distal acquired lacrimal disorders (DALO). However, no unanimous consensus has been achieved on which of these surgeries is the most suitable to the individual patient. Herein, we review the available literature of the last 30 years with the aim of defining a simple and reproduceable treatment algorithm to treat DALO. A search of PubMed, EMBASE, Scopus and Cochrane databases was last performed in December 2021 to examine evidence regarding the role of END-DCR and EXT-DCR in primary and revision surgeries. If considered primary surgeries, END-DCR should be preferred in case of intranasal comorbidities, given the possibility to directly visualize and treat potential intranasal pathologies. Conversely, EXT-DCR should be chosen in case of need/preference for local anesthesia, given the major historical experience and wider surgical field that helps to resolve intra-operatory complications (e.g., bleeding) in an uncollaborative patient. In the absence of the abovementioned conditions, the decision of one or other approach should be discussed with the patient. In recurrent cases, END-DCR should be considered the treatment of choice given the major likelihood to visualize the causes of primary failure and directly resolve it. In conclusion, END-DCR should be considered the treatment of choice in revision cases or in primary ones associated with intranasal pathologies, whereas EXT-DCR should be chosen if local anesthesia is needed. In the absence of these scenarios, it is still open to debate which of these two approaches should be used.
Topics: Humans; Dacryocystorhinostomy; Lacrimal Apparatus; Endoscopy; Lacrimal Apparatus Diseases; Reoperation; Treatment Outcome; Nasolacrimal Duct; Lacrimal Duct Obstruction
PubMed: 36254409
DOI: 10.1177/11206721221132746 -
Experimental Eye Research May 2006The lacrimal gland is the main contributor to the aqueous layer of the tear film. It secretes proteins, electrolytes and water, which helps to nourish and protect the... (Review)
Review
The lacrimal gland is the main contributor to the aqueous layer of the tear film. It secretes proteins, electrolytes and water, which helps to nourish and protect the ocular surface. Lacrimal gland secretion is primarily under neural control, which is achieved through a neural reflex arc. Stimuli to the ocular surface activate afferent sensory nerves in the cornea and conjunctiva. This in turn activates efferent parasympathetic and sympathetic nerves in the lacrimal gland to stimulate secretion. Sex steroid hormones are also important regulators of lacrimal gland functions. A decrease or lack of lacrimal gland secretion is the leading cause of aqueous tear deficient dry eye syndrome (DES). It has been suggested that DES is an inflammatory disorder that affects the ocular surface and the lacrimal gland. In several pathological instances, the lacrimal gland can become a target of the immune system and show signs of inflammation. This can result from autoimmune diseases (Sjögren's syndrome), organ transplantation (graft versus host disease), or simply as a result of aging. The hallmarks of lacrimal gland inflammation are the presence of focal lymphocytic infiltrates and increased production of proinflammatory cytokines. The mechanisms leading to lacrimal gland dysfunction are still poorly understood. Apoptosis, production of autoantibodies, hormonal imbalance, alterations in signaling molecules, neural dysfunction, and increased levels of proinflammatory cytokines have been proposed as possible mediators of lacrimal gland insufficiency in disease states.
Topics: Animals; Autoimmunity; Autonomic Nervous System; Cytokines; Dacryocystitis; Dry Eye Syndromes; Humans; Inflammation Mediators; Lacrimal Apparatus; Mice; Signal Transduction; Sjogren's Syndrome
PubMed: 16309672
DOI: 10.1016/j.exer.2005.10.018 -
International Journal of Medical... 2016To explore the prevalence of lacrimal duct obstruction in patients with infectious keratitis, and the necessity of lacrimal duct dredge in the treatment of human...
To explore the prevalence of lacrimal duct obstruction in patients with infectious keratitis, and the necessity of lacrimal duct dredge in the treatment of human infectious keratitis. The design is prospective, non-control case series. Thirty-one eyes from twenty-eight continuous patients with infectious keratitis were included in this study. The presence/absence of lacrimal duct obstruction was determined by the lacrimal duct irrigation test. The diagnosis of infectious keratitis was made based on clinical manifestations, cornea scraping microscopic examination and bacterial/fungus culture. Diagnosis of viral keratitis was set up based on the recurrent history, deep neovascularization and typical outlook of the cornea scar. The treatment of keratitis included drugs, eye drops or surgery, while treatment of chronic dacryocystitis was lacrimal duct dredging with supporting tube implantation surgery. In the thirty-one eyes with infectious keratitis, fifteen suffered from fungal keratitis (48%), two bacterial keratitis (6%), and fourteen viral keratitis (45%). Eleven eyes (35%) from ten patients with infectious keratitis also suffered from lacrimal duct obstruction. In those cases, six eyes also suffered from lower canalicular obstruction, three nasolacrimal duct obstruction and chronic dacryocystitis, one a combination of upper and lower canalicular obstruction, one upper canalicular obstruction. After local and systemic applications of anti-bacterial, anti-viral, anti-fungal and anti-inflammatory drugs, twenty-eight eyes (90%) recovered within three weeks, while the ulceration of three patients required the lacrimal duct dredging and supporting tube implantation surgery for the healing. Herein, we first report that the prevalence of infectious keratitis is closely correlated to the occurrence of lacrimal duct obstruction. When both confirmed, simultaneous treatment of keratitis and lacrimal duct obstruction promptly is required. Further evaluation of mechanism, prevention and control of the diseases are warranted.
Topics: Adult; Aged; Aged, 80 and over; Animals; China; Dacryocystitis; Endoscopy; Eye Infections, Fungal; Female; Humans; Keratoconjunctivitis, Infectious; Lacrimal Apparatus; Lacrimal Duct Obstruction; Male; Middle Aged; Prevalence; Prospective Studies; Young Adult
PubMed: 27766030
DOI: 10.7150/ijms.16515 -
Acta Otorhinolaryngologica Italica :... Apr 2021
Topics: Humans; Lacrimal Apparatus
PubMed: 34060525
DOI: 10.14639/0392-100X-suppl.1-41-2021-10 -
Korean Journal of Radiology Oct 2022To compare the clinical and radiological features of various etiologies of chronic diffuse lacrimal gland enlargement.
OBJECTIVE
To compare the clinical and radiological features of various etiologies of chronic diffuse lacrimal gland enlargement.
MATERIALS AND METHODS
We retrospectively reviewed 91 consecutive patients who underwent surgical biopsy for chronic diffuse lacrimal gland enlargement and were diagnosed with non-specific dacryoadenitis (DA) (n = 42), immunoglobulin G4-related dacryoadenitis (IgG4-RD) (n = 33), and lymphoma (n = 16). Data on patient demographics, clinical presentation, and CT imaging findings (n = 73) and MRI (n = 43) were collected. The following radiologic features of lacrimal gland enlargement were evaluated: size, unilaterality, wedge sign, angle with the orbital wall, heterogeneity, signal intensity, degree of enhancement, patterns of dynamic contrast-enhanced, and apparent diffusion coefficient value. Radiological features outside the lacrimal glands, such as extra-lacrimal orbital involvement and extra-orbital head and neck involvement, were also evaluated. The clinical and radiological findings were compared among the three diseases.
RESULTS
Compared to the DA and IgG4-RD groups, the lymphoma group was significantly older (mean 59.9 vs. 46.0 and 49.4 years, respectively; = 0.001) and had a higher frequency of unilateral involvement (62.5% vs. 31.0% and 15.2%, respectively; = 0.004). Compared to the IgG4-RD and lymphoma groups, the DA group had significantly smaller lacrimal glands (2.3 vs. 2.8 and 3.3 cm, respectively; < 0.001) and a lower proportion of cases with a wedge sign (54.8% vs. 84.8% and 87.5%, respectively; = 0.005). The IgG4-RD group showed more frequent involvement of the extra-orbital head and neck structures, including the infraorbital nerve (36.4%), paranasal sinus (72.7%), and salivary gland (58.6%) compared to the DA and lymphoma groups (4.8%-28.6%) (all < 0.005).
CONCLUSION
Patient age, unilaterality, lacrimal gland size, wedge sign, and extra-orbital head and neck involvement differed significantly different between lymphoma, DA, and IgG4-RD. Our results will be useful for the differential diagnosis and proper management of chronic lacrimal gland enlargement.
Topics: Biopsy; Dacryocystitis; Humans; Immunoglobulin G; Immunoglobulin G4-Related Disease; Lacrimal Apparatus; Retrospective Studies
PubMed: 36098340
DOI: 10.3348/kjr.2022.0233