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Biochemistry of human tear film: A review. Exp Eye Res 2022; 220:109101. [DOI: 10.1016/j.exer.2022.109101] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 04/18/2022] [Accepted: 04/26/2022] [Indexed: 12/13/2022]
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2
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Musayeva A, Gericke A, Jäger F, Paulsen F, Braun M, Fabry B, Braun R, Pauly D, Holtmann C, Geerling G. [Results of the Dry Eye Research Grant Award 2016]. Ophthalmologe 2021; 118:337-344. [PMID: 32638094 PMCID: PMC8043874 DOI: 10.1007/s00347-020-01163-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The Sicca-Förderpreis (Dry Eye Award) supports the development of scientific research on the pathogenesis, diagnostics, and treatment of dry eye and ocular surface diseases. It is awarded after a limited call for proposals in German-speaking countries, written application and selection of the award winner after evaluation by a jury of ophthalmologists working in basic and clinical science. In this article examples of the results of funded projects of the Sicca-Förderpreis 2016 are cursorily described, which were presented at the Ophthalmological Academy of Germany 2019 (Augenärztliche Akademie Deutschland 2019) and therefore provide an insight into current scientific developments. The role of muscarinic receptors and those of urea in the pathogenesis of dry eye as well as the (missing) correlation of tear film stability, viscosity and surface tension are highlighted. A project on the early detection of ocular involvement in graft versus host disease and the idea of treating meibomian gland dysfunction with eyelid surgery techniques are also groundbreaking. The outlined projects represent the potential for further substantial developments in the understanding, diagnostics and treatment of dry eye; however, their long-term clinical relevance still needs to be established.
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Affiliation(s)
- A Musayeva
- Augenklinik und Poliklinik, Klinikum der Johannes-Gutenberg-Universität Mainz, Mainz, Deutschland
| | - A Gericke
- Augenklinik und Poliklinik, Klinikum der Johannes-Gutenberg-Universität Mainz, Mainz, Deutschland
| | - F Jäger
- Institut für Funktionelle und Klinische Anatomie, FAU Erlangen-Nürnberg, Erlangen, Deutschland
| | - F Paulsen
- Institut für Funktionelle und Klinische Anatomie, FAU Erlangen-Nürnberg, Erlangen, Deutschland
| | - M Braun
- Institut für Physik der kondensierten Materie, FAU Erlangen-Nürnberg, Erlangen, Deutschland
| | - B Fabry
- Institut für Physik der kondensierten Materie, FAU Erlangen-Nürnberg, Erlangen, Deutschland
| | - R Braun
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Regensburg, Regensburg, Deutschland
| | - D Pauly
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Regensburg, Regensburg, Deutschland
| | - C Holtmann
- Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - G Geerling
- Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland.
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Tóth-Molnár E, Ding C. New insight into lacrimal gland function: Role of the duct epithelium in tear secretion. Ocul Surf 2020; 18:595-603. [DOI: 10.1016/j.jtos.2020.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/21/2020] [Accepted: 07/07/2020] [Indexed: 02/08/2023]
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4
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Pflugfelder SC, Stern ME. Biological functions of tear film. Exp Eye Res 2020; 197:108115. [PMID: 32561483 DOI: 10.1016/j.exer.2020.108115] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/05/2020] [Accepted: 06/08/2020] [Indexed: 02/06/2023]
Abstract
Tears have a vital function to protect and lubricate the ocular surface. Tear production, distribution and clearance is tightly regulated by the lacrimal functional unit (LFU) to meet ocular surface demands. The tear film consists of an aqueous-mucin layer, containing fluid and soluble factors produced by the lacrimal glands and mucin secreted by the goblet cells, that is covered by a lipid layer. The array of proteins, glycoproteins and lipids in tears function to maintain a stable, well-lubricated and smooth optical surface. Tear factors also promote wound healing, suppress inflammation, scavenge free radicals, and defend against microbial infection. Disease and dysfunction of the LFU leads to tear instability, increased evaporation, inflammation, and blurred and fluctuating vision. The function of tear components and the consequences of tear deficiency on the ocular surface are reviewed.
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Affiliation(s)
- Stephen C Pflugfelder
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States.
| | - Michael E Stern
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States; ImmunEyez, Mission Viejo, CA, United States.
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Murugesan V, Dwivedi R, Saini M, Gupta V, Dada T, Vivekanandhan S. Tear neuromediators in eyes on chronic topical antiglaucoma therapy with and without BAK preservatives. Br J Ophthalmol 2019; 105:141-148. [PMID: 31383648 DOI: 10.1136/bjophthalmol-2019-314234] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 06/18/2019] [Accepted: 07/19/2019] [Indexed: 11/03/2022]
Abstract
PURPOSE To evaluate tear neuropeptides (NPs) (vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP), substance P (SP), nerve growth factor (NGF)) in chronic ocular topical hypotensive therapy with and without benzalkonium chloride (BAK) preservative. METHODS A comparative, open label, cross-sectional study of patients using antiglaucoma medications for >6 months with BAK (group I), without BAK (group II) and controls was done. Tear NPs (ELISA), ocular surface evaluation tests (tear breakup time (TBUT), Schirmer's test, corneal and conjunctival staining score) and confocal central corneal subbasal nerve fibre layer (SBNFL) imaging was done. RESULTS Of 153 eyes evaluated, group 1 (82 eyes (41 patients; mean age 48±14.5 years)) and group 2 (71 eyes (36 patients; mean age 43.11±15 years)) were on therapy for a mean duration of 10.05±2.0 and 9.67±2.3 months, respectively. Tear analysis showed elevated SP and NGF (p<0.01); decreased CGRP (p=0.03), VIP and NPY (p<0.01) compared with controls (n=30, mean age 29.33±5.7 years). Tear NP levels (SP (p=0.1), NGF (p=0.33), CGRP (p=1), VIP (p=0.87), NPY (p=0.83)) and SBNFL (p=0.09) were comparable in both groups. There was no correlation seen between tear NP levels and clinical tests and SBNFL. CONCLUSION Our study analysis points towards altered tear NP levels in eyes on chronic topical hypotensive therapy in comparison with controls with no significant difference in tear NP levels and central corneal SBNFL density between the BAK preservative and BAK-free antiglaucoma therapy.
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Affiliation(s)
- Vanathi Murugesan
- Dr R P Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Delhi, India
| | - Roopa Dwivedi
- Dr R P Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Delhi, India
| | - Manu Saini
- Dr R P Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Delhi, India
| | - Viney Gupta
- Dr R P Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Delhi, India
| | - Tanuj Dada
- Dr R P Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Delhi, India
| | - S Vivekanandhan
- Neurobiochemistry Lab, C N Centre, All India Institute of Medical Sciences, New Delhi, India
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6
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The Intriguing Role of Neuropeptides at the Ocular Surface. Ocul Surf 2017; 15:2-14. [DOI: 10.1016/j.jtos.2016.10.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 10/05/2016] [Accepted: 10/26/2016] [Indexed: 02/02/2023]
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7
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Diadenosine tetraphosphate contributes to carbachol-induced tear secretion. Purinergic Signal 2014; 11:87-93. [PMID: 25398705 DOI: 10.1007/s11302-014-9434-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 11/06/2014] [Indexed: 10/24/2022] Open
Abstract
The purpose of this study is to investigate if the cholinergic stimulation by carbachol on tear secretion is a direct process or if it is also mediated by purinergic mechanisms. Experiments were performed in New Zealand male rabbits. The amount of tear secretion was measured with Schirmer's test and then analyzed by a HPLC protocol in order to study the nucleotide levels. Animal eyes were instilled with carbachol (a cholinergic agonist), pirenzepine, gallamine and 4-DAMP (muscarinic antagonists), PPADS, suramin and reactive blue 2 (purinergic antagonists), and a P2Y2 receptor small interfering RNA (siRNA). Tear secretion increased with the instillation of carbachol, approximately 84 % over control values 20 min after the instillation and so did Ap4A and ATP release. When we applied carbachol in the presence of muscarinic antagonists, tear volume only increased to 4 % with atropine, 12 % in the case of pirenzepine, 3 % with gallamine, and 8 % with 4-DAMP. In the presence of carbachol and purinergic antagonists, tear secretion was increased to 12 % (all values compared to basal tear secretion). By analyzing tear secretion induced with carbachol in presence of a P2Y2 receptor siRNA, we found that tear secretion was diminished to 60 %. The inhibition of tear secretion in the presence of carbachol and purinergic antagonists or P2Y2 siRNA occurred with no apparent change in the tear amount of Ap4A. These experiments demonstrated the participation of Ap4A in lacrimal secretion process.
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Functional and Histologic Changes in the Lacrimal Gland After Botulinum Toxin Injection. J Craniofac Surg 2013; 24:1960-9. [DOI: 10.1097/scs.0b013e31829ac655] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Abstract
Introduction. Dry eye disease or dysfunctional tear syndrome is among the
most frequently established diagnoses in ophthalmology. It can be defined as
a disorder of the tear film resulting in changes in the ocular surface.
Mechanisms in development of dry eye disease. There are many factors causing
dry eye and they can be related to deficiency in any of the components of the
tear film. It has been suggested that dry eye is an inflammatory disorder
that affects the ocular surface and lacrimal gland. Inflammation is the most
important mechanism of corneal and conjunctival cell damage, which is
responsible for the symptoms and signs of ocular surface pathology. Hormonal
imbalance (particularly androgens), neural dysfunction, increased levels of
pro-inflammatory cytokines and loss of immune homeostasis of the lacrimal
gland and ocular surface could be possible mechanisms in the pathogenesis of
dry eye disease. Discussion. The aim of this paper was to review the advances
in the pathogenesis and management of the dry eye disease. The appropriate
dry eye treatment presupposes knowledge of all existing pharmacologic and
non-pharmacologic therapeutic modalities. The mainstay of therapy is still
artificial tears, with anti-inflammatory therapy and punctual occlusion
therapy as second and third line therapies.
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Situ P, Simpson TL, Jones LW, Fonn D. Conjunctival and Corneal Hyperesthesia in Subjects with Dryness Symptoms. Optom Vis Sci 2008; 85:867-72. [DOI: 10.1097/opx.0b013e3181852788] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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12
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Functional expression of the adenosine A1 receptor in rabbit lacrimal gland. Exp Eye Res 2008; 86:110-7. [DOI: 10.1016/j.exer.2007.09.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 09/26/2007] [Accepted: 09/28/2007] [Indexed: 11/24/2022]
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Klenkler B, Sheardown H, Jones L. Growth Factors in the Tear Film: Role in Tissue Maintenance, Wound Healing, and Ocular Pathology. Ocul Surf 2007; 5:228-39. [PMID: 17660896 DOI: 10.1016/s1542-0124(12)70613-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Numerous biologically active growth factors are secreted by the lacrimal gland and distributed via the tears over the ocular surface, where they affect cellular proliferation, migration, differentiation, and survival. The role of growth factors and their receptors in maintenance of tissue homeostasis and wound healing continues to be elucidated, and the effect of growth factor imbalances in ocular surface diseases is just beginning to be understood. For instance, in eyes with ocular surface diseases, including conjunctivitis, corneal erosion, keratitis, and corneal ulcers, epidermal growth factor release rates have been shown to be significantly lower than in normal eyes during reflex tearing. Future research into the mechanisms of dry eye disease will focus on reasons for decreased tear and growth factor production in the neuronal reflex loop or the acinar lacrimal gland cells. Animal models to test therapeutic approaches must be developed.
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Affiliation(s)
- Bettina Klenkler
- Department of Chemical Engineering, McMaster University, Hamilton, ON, Canada
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Wu K, Jerdeva GV, da Costa SR, Sou E, Schechter JE, Hamm-Alvarez SF. Molecular mechanisms of lacrimal acinar secretory vesicle exocytosis. Exp Eye Res 2006; 83:84-96. [PMID: 16530759 DOI: 10.1016/j.exer.2005.11.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 10/12/2005] [Accepted: 11/01/2005] [Indexed: 11/26/2022]
Abstract
The acinar epithelial cells of the lacrimal gland are responsible for the production, packaging and regulated exocytosis of tear proteins into ocular surface fluid. This review summarizes new findings on the mechanisms of exocytosis in these cells. Participating proteins are discussed within the context of different categories of trafficking effectors including targeting and specificity factors (rabs, SNAREs) and transport factors (microtubules, actin filaments and motor proteins). Recent information describing fundamental changes in basic exocytotic mechanisms in the NOD mouse, an animal model of Sjögren's syndrome, is presented.
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Affiliation(s)
- Kaijin Wu
- Department of Pharmaceutical Sciences, School of Pharmacy, 1985 Zonal Avenue, University of Southern California, Los Angeles, CA 90033, USA
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da Costa SR, Wu K, MacVeigh M, Pidgeon M, Ding C, Schechter JE, Hamm-Alvarez SF. Male NOD mouse external lacrimal glands exhibit profound changes in the exocytotic pathway early in postnatal development. Exp Eye Res 2005; 82:33-45. [PMID: 16005870 PMCID: PMC1351294 DOI: 10.1016/j.exer.2005.04.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Revised: 04/14/2005] [Accepted: 04/27/2005] [Indexed: 10/25/2022]
Abstract
The lacrimal glands of male NOD mice exhibit many of the features of the human lacrimal gland in patients afflicted with the autoimmune disease, Sjögren's syndrome, including loss of secretory functions and lymphocytic infiltration into the lacrimal gland. To elucidate the early changes in the secretory pathway associated with development of Sjögren's syndrome, we investigated the organization of the exocytotic pathway in lacrimal glands of age-matched male BALB/c and NOD mice. Cryosections from lacrimal glands from 1 and 4 month male BALB/c and NOD mice were processed for confocal fluorescence and electron microscopic evaluation of different participants in exocytosis. No changes in apical actin filaments were noted in glands from NOD mice, but these glands exhibited thickening of basolateral actin relative to that seen in the BALB/c mice. Rab3D immunofluorescence associated with mature secretory vesicles was distributed abundantly in a continuous vesicular network concentrated beneath the apical plasma membrane in glands from 1 and 4 month BALB/c mice. In glands from 1 month NOD mice, rab3D immunofluorescence exhibited marked discontinuity and irregularity in the vesicular labeling pattern. While this change was also detected in glands from 4 month NOD mice, many of these glands exhibited an additional extension of rab3D labeling through the cell to the basolateral membrane. Electron microscopic analysis confirmed the formation of irregularly shaped, unusually large secretory vesicles in lacrimal glands from NOD mice. Quantitation of multiple secretory vesicles from electron micrographs revealed a significant (p< or =0.05) increase in the percentage of secretory vesicles incorporated into multivesicular aggregates in lacrimal glands from 1 and 4 month NOD mice compared to BALB/c mice. The M3 muscarinic receptor, a key signaling effector of exocytosis, was redistributed away from its normally basolateral locale in glands from BALB/c mice, with concomitant enrichment in intracellular aggregates in glands from NOD mice. These findings show that lacrimal glands in NOD mice as young as 1 month contain aberrant secretory vesicles with altered effector composition that undergo premature cytoplasmic fusion, and that changes in the distribution of the M3 muscarinic receptor occur within the same time frame.
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Affiliation(s)
| | - Kaijin Wu
- Departments of Pharmaceutical Sciences
| | - Michelle MacVeigh
- USC Center for Liver Diseases, University of Southern California, Los Angeles CA 90033
| | | | | | | | - Sarah F. Hamm-Alvarez
- Departments of Pharmaceutical Sciences
- Physiology and Biophysics and
- Ophthalmology and
- *Address correspondence to: Sarah F. Hamm-Alvarez, Ph. D., USC School of Pharmacy, 1985 Zonal Avenue, Los Angeles CA 90033, 323-442-1445 O, 323-442-1390 F,
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Ríos JD, Horikawa Y, Chen LL, Kublin CL, Hodges RR, Dartt DA, Zoukhri D. Age-dependent alterations in mouse exorbital lacrimal gland structure, innervation and secretory response. Exp Eye Res 2005; 80:477-91. [PMID: 15781275 PMCID: PMC3243076 DOI: 10.1016/j.exer.2004.10.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 10/29/2004] [Indexed: 10/26/2022]
Abstract
Several studies investigated the effect of aging on rat and human lacrimal gland physiology. However, in most of these studies, only two age groups were investigated. Furthermore, those studies did not correlate the age-related histological changes that occur in the lacrimal gland to the functional changes (nerve activity and protein secretion) that might occur with aging. Thus, the purpose of the present study was to investigate the effect of aging on lacrimal gland structure, innervation and function using BALB/c mice at different ages. Exorbital lacrimal glands were removed from 3, 8, 12, 24, and 32-month-old, male BALB/c mice, fixed, embedded and processed for histology and immunohistochemistry. Sections were stained with hematoxylin and eosin to determine morphological changes and lymphocytic infiltration; giemsa to identify mast cells; and Kinyoun's carbol fucsin solution to indicate lipofuscin-like inclusions. Parasympathetic and sympathetic nerves were identified by immunofluorescence techniques. To measure acetylcholine release and protein secretion, lacrimal gland pieces were incubated in Krebs Ringer buffer containing 5 mM KCl (control), 75 mM KCl (depolarizing buffer which activates nerves), carbachol (a cholinergic agonist, 10(-4) M), or phenylephrine (an alpha1-adrenergic agonist, 10(-4) M) for 20 min. The media were collected and analysed for acetylcholine and peroxidase using a spectrofluorometric assay. KCl-, carbachol- and phenylephrine-stimulated peroxidase secretion decreased in lacrimal glands from 8, 12, and 24-month-old mice when compared to 3-month-old animals. Both the density and distribution of parasympathetic and sympathetic nerves surrounding the acini decreased with increasing age. Acetylcholine release from lacrimal gland nerves decreased in 24-month-old mice compared to 3- and 12-month-old animals. Similarly, progressive morphological changes, including increased numbers of lipofuscin-like inclusions, mast cells and lymphocytic infiltration occurred in an age-dependent manner. We conclude that structural alterations of mouse lacrimal gland, including increased accumulation of lipofuscin-like inclusions, chronic inflammation and functional alterations including decreased acetylcholine release and protein secretion occurred with aging.
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Affiliation(s)
- José David Ríos
- Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, 20 Staniford St., 02114 Boston, MA, USA.
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Chen LL, Johansson JK, Hodges RR, Zoukhri D, Ghinelli E, Rios JD, Dartt DA. Differential effects of the EGF family of growth factors on protein secretion, MAPK activation, and intracellular calcium concentration in rat lacrimal gland. Exp Eye Res 2005; 80:379-89. [PMID: 15721620 DOI: 10.1016/j.exer.2004.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Accepted: 10/04/2004] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to investigate the expression of the EGF family of growth factors and EGF receptor subtypes (ErbB1-4) present in lacrimal gland and determine the effects of these growth factors on different functions of rat lacrimal gland. RT-PCR was used to detect mRNA expression in the lacrimal gland of selected members of the EGF family of growth factors, namely EGF, transforming growth factor alpha (TGF-alpha), heparin-binding EGF (HB-EGF), and heregulin. The presence of ErbB receptors was investigated by immunofluorescence microscopy and western blot analysis. The effects of EGF, TGF-alpha, HB-EGF, and heregulin on protein secretion from lacrimal gland acini were examined using a fluorescent assay for peroxidase, a marker of protein secretion. Fura-2 tetra-acetoxymethyl ester was used to measure the effects of the growth factors on intracellular [Ca2+] ([Ca2+]i) in acini. MAPK activation in acini by these growth factors was also examined by western blot analysis using antibodies specific to phosphorylated p42/44 MAPK and total p42 MAPK. Rat lacrimal gland expressed EGF, TGF-alpha, HB-EGF, and heregulin mRNA, and all four ErbB receptors were present in the lacrimal gland as detected by western blot analyses. ErbB 1 and ErbB2 were located in basal and lateral membranes of acinar and ductal cells. The location of ErbB3 could not be determined while ErbB4 was found in ductal cells. Heregulin (10(-7) m) significantly increased protein secretion in lacrimal gland acini whereas all growth factors tested significantly increased [Ca2+]i at 10(-7) m. TGF-alpha (10(-9) m), heregulin (10(-7) m), EGF (10(-7) m), and HB-EGF (10(-7) m) significantly increased the amount of phosphorylated MAPK in lacrimal gland acini. We conclude that all members of the EGF family of growth factors studied are synthesised in rat lacrimal gland, could activate all four ErbB receptors that are present in this tissue, and differentially activate lacrimal gland functions.
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Affiliation(s)
- L L Chen
- Schepens Eye Research Institute, Harvard Medical School, Department of Ophthalmology, 20 Staniford Street, Boston, MA 02114, USA
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Grönlund MA, Stenevi U, Lundeberg T. Acupuncture treatment in patients with keratoconjunctivitis sicca: a pilot study. ACTA ACUST UNITED AC 2004; 82:283-90. [PMID: 15115449 DOI: 10.1111/j.1600-0420.2004.00254.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM To evaluate the effects of acupuncture in patients with keratoconjunctivitis sicca (KCS). MATERIAL AND METHODS Twenty-five patients (20 women, five men) with KCS were randomly assigned to an acupuncture treatment group or a control group. The effects of acupuncture were evaluated by a questionnaire on symptoms, visual analogue scale recordings, registration of drop frequency, and dry eye tests. Ten acupuncture sessions were given. Follow-up was carried out after 2-3 weeks and again after a mean period of 8 months. RESULTS Patients receiving acupuncture felt better at the first follow-up compared with the control group (p = 0.036). However, no statistical significance could be found concerning any change, or difference, in the total number of subjective symptoms, dosage frequency or, as indicated by the dry eye tests, tear quality, tear secretion and ocular surface disease. CONCLUSION The results indicate that acupuncture has subjective beneficial effects in patients with KCS and could therefore be tried as a complement to ordinary treatment.
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Affiliation(s)
- Marita Andersson Grönlund
- Institute of Clinical Neuroscience, Section of Ophthalmology, Sahlgrenska Academy at Gothenburg University, Sweden.
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Dartt DA. Interaction of EGF family growth factors and neurotransmitters in regulating lacrimal gland secretion. Exp Eye Res 2004; 78:337-45. [PMID: 15106911 DOI: 10.1016/s0014-4835(03)00202-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The lacrimal gland is the primary source for the aqueous portion of the tear film. This portion contains water, electrolytes and proteins, which are necessary for the health and maintenance of the cells of the ocular surface. Afferent sensory nerves in the cornea and conjunctiva stimulate efferent parasympathetic and sympathetic nerves in the lacrimal gland. Cholinergic agonists, released from parasympathetic nevres, and norepinephrine, released from sympathetic nerves, are major stimuli of lacrimal gland secretion. These neurotransmitters activate distinct, but overlapping signal transduction pathways leading to lacrimal gland secretion. Other stimuli of lacrimal gland secretion are the EGF family of growth factors. In addition to stimulation of secretion, these growth factors can interact with the cells of the lacrimal gland themselves or with the cells of the ocular surface depending upon the location from which these growth factors are released. This review will focus on the effects of the EGF family of growth factors on the lacrimal gland and their interactions with the pathways stimulated by the neurotransmitters released from nerves.
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Affiliation(s)
- Darlene A Dartt
- Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA.
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Xie J, Qian L, Wang Y, Rose CM, Yang T, Nakamura T, Hamm-Alvarez SF, Mircheff AK. Novel biphasic traffic of endocytosed EGF to recycling and degradative compartments in lacrimal gland acinar cells. J Cell Physiol 2004; 199:108-25. [PMID: 14978740 DOI: 10.1002/jcp.10458] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of this study was to delineate the traffic patterns of EGF and EGF receptors (EGFR) in primary cultured acinar epithelial cells from rabbit lacrimal glands. Uptake of [(125)I]-EGF exhibited saturable and non-saturable, temperature-dependent components, suggesting both receptor-mediated and fluid phase endocytosis. Accumulation of [(125)I] was time-dependent over a 120-min period, but the content of intact [(125)I]-EGF decreased after reaching a maximum at 20 min. Analytical fractionation by sorbitol density gradient centrifugation and phase partitioning indicated that within 20 min at 37 degrees C [(125)I] reached an early endosome, basal-lateral recycling endosome, pre-lysosome, and lysosome. Small components of the label also appeared to reach the Golgi complex and trans-Golgi network. Intact [(125)I]-EGF initially accumulated in the recycling endosome; the content in the recycling endosome subsequently decreased, and by 120 min increased amounts of [(125)I]-labeled degradation products appeared in the pre-lysosomes and lysosomes. Confocal microscopy imaging of FITC-EGF and LysoTrackerRed revealed FITC enriched in a dispersed system of non-acidic compartments at 20 min and in acidic compartments at 120 min. Both confocal immunofluorescence microscopy and analytical fractionation indicated that the intracellular EGFR pool was much larger than the plasma membrane-expressed pool at all times. Cells loaded with [(125)I]-EGF released a mixture of intact EGF and [(125)I]-labeled degradation products. The observations indicate that in lacrimal acinar cells, EGFR and EGF-EGFR complexes continually traffic between the plasma membranes and a system of endomembrane compartments; EGF-stimulation generates time-dependent signals that initially decrease, then increase, EGF-EGFR traffic to degradative compartments.
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Affiliation(s)
- Jiansong Xie
- Department of Physiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
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21
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Abstract
Pharmacologically active preparations directed towards modulating muscarinic receptor activity in the eye have been used for over 2000 years when extracts from Atropa belladonna were first applied to enhance eye appearance through pupillary dilation. The first clinically active drugs targeting a specific eye disease were anticholinesterases (e.g. ecothiophate) applied as eye drops to treat glaucoma in the 1960's. However, cataract was soon detected as a relatively frequent side effect and such drugs are now only used to treat glaucoma as a last resort. As muscarinic agonists have been found to reduce intraocular pressure both by decreasing aqueous humour production (through Na,K-ATPase pump inhibition) and increasing outflow (by muscle contraction), it is likely that treatments will be developed that target specific muscarinic subtypes. Recently, it has been shown that the M1 receptor subtype predominates in the lens. It is therefore important that this subtype is not targeted in future ocular therapies so that the side-effect of cataract is avoided. Form-deprived myopia resulting from an increased axial length in the affected eye can be reduced by the application of atropine. This effect has been achieved both in a chick model system and in human clinical trials, and in the former system atropine has been shown to reduce the production of scleral extracellular proteins. Carbachol stimulates tear fluid production through the activation of muscarinic receptors. Interestingly, at least part of the stimulation occurs via epidermal growth factor (EGF) receptors and although the precise signalling mechanisms are not completely understood, it has been shown that calcium mobilisation plays a critical role in both muscarinic and EGF receptor activity. It should be noted that in the four examples described above, the cell types responsible for producing the physiological output are non-neuronal in origin. Therefore cholinergic receptor activation plays diverse roles in the eye and pharmacological intervention based on specific receptor sub-types has potential benefit in a number of ocular problems. However, potential side effects have also recently been identified.
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Affiliation(s)
- G Duncan
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
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22
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Hodges RR, Dartt DA. Regulatory pathways in lacrimal gland epithelium. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 231:129-96. [PMID: 14713005 DOI: 10.1016/s0074-7696(03)31004-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Tears are a complex fluid that continuously cover the exposed surface of the eye, namely the cornea and conjunctiva. Tears are secreted in response to the multitude of environmental stresses that can harm the ocular surface such as cold, mechanical stimulation, physical injury, noxious chemicals, as well as infections from various organisms. Tears also provide nutrients and remove waste from cells of the ocular surface. Because of the varied function of tears, tears are complex and are secreted by several different tissues. Tear secretion is under tight neural control allowing tears to respond rapidly to changing environmental conditions. The lacrimal gland is the main contributor to the aqueous portion of the tear film and the regulation of secretion from this gland has been well studied. Despite multiple redundencies in pathways to stimulate secretion from the lacrimal gland, defects can occur resulting in dry eye syndromes. These diseases can have deleterious effects on vision. In this review, we summarize the latest information regarding the regulatory pathways, which control secretion from the lacrimal gland, and their roles in the pathogenesis of dry eye syndromes.
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Affiliation(s)
- Robin R Hodges
- Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
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23
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Abstract
Tears play a vital role in the health and protection of the cornea and conjunctiva. The tear film consists of multiple layers and different glands secrete each layer. Because of many and varied requirements of the ocular surface cells, the volume, composition and structure of the tear film must be exquisitely controlled. If any layer of the tear film is disrupted or altered, the entire tear film is affected, often with deleterious effects. This chapter reviews the current knowledge of the neural and growth factor regulation of electrolyte, water and protein secretion from the goblet and stratified squamous cells of the conjunctiva as well as the mechanisms used for fluid secretion. The evidence presented in this review suggests that parasympathetic nerves stimulate goblet, but not stratified squamous, cell secretion. Sympathetic nerves stimulate stratified squamous, but not goblet, cell secretion, while P2Y(2) agonists stimulate secretion from both cell types. Growth factors regulate goblet cell secretion, but their effects on stratified squamous cell secretion are unknown.
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Affiliation(s)
- Darlene A Dartt
- The Department of Ophthalmology, The Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA.
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Calcium Signalling in Ocular Tissues: Functional Activity of G-protein and Tyrosine–Kinase Coupled Receptors. Exp Eye Res 2002. [DOI: 10.1006/exer.2002.2033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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