Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 9 de 9
Filter
1.
Biogerontology ; 17(4): 749-61, 2016 08.
Article in English | MEDLINE | ID: mdl-27125427

ABSTRACT

Collagen XVIII has the structural properties of both collagen and proteoglycan. It has been found at the basement membrane/stromal interface where it is thought to mediate their attachment. Endostatin, a proteolytic fragment from collagen XVIII C-terminal end has been reported to possess anti-angiogenic properties. Age-related vision loss in collagen XVIII mutant mice has been accompanied with a pathological accumulation of deposits under the retinal pigment epithelium (RPE). We have recently demonstrated that impaired proteasomal and autophagy clearance are associated with the pathogenesis of age-related macular degeneration. This study examined the staining levels of proteasomal and autophagy markers in the RPE of different ages of the Col18a1 (-/-) mice. Eyes from 3, 6-7, 10-13 and 18 months old mice were enucleated and embedded in paraffin according to the routine protocol. Sequential 5 µm-thick parasagittal samples were immunostained for proteasome and autophagy markers ubiquitin (ub), SQSTM1/p62 and beclin-1. The levels of immunopositivity in the RPE cells were evaluated by confocal microscopy. Collagen XVIII knock-out mice had undergone age-related RPE degeneration accompanied by an accumulation of drusen-like deposits. Ub protein conjugate staining was prominent in both RPE cytoplasm and extracellular space whereas SQSTM1/p62 and beclin-1 stainings were clearly present in the basal part of RPE cell cytoplasm in the Col18a1 (-/-) mice. SQSTM1/p62 displayed mild extracellular space staining. Disturbed proteostasis regulated by collagen XVIII might be responsible for the RPE degeneration, increased protein aggregation, ultimately leading to choroidal neovascularization.


Subject(s)
Aging/metabolism , Collagen/metabolism , Macular Degeneration/metabolism , Proteostasis Deficiencies/metabolism , Retinal Pigment Epithelium/metabolism , Aging/pathology , Animals , Female , Macular Degeneration/pathology , Male , Mice , Mice, Knockout , Proteostasis Deficiencies/pathology , Retinal Pigment Epithelium/pathology
2.
Am J Pathol ; 178(5): 2058-65, 2011 May.
Article in English | MEDLINE | ID: mdl-21514421

ABSTRACT

In the tear fluid the outermost part facing the tear-air interface is composed of lipids preventing evaporation of the tears. Phospholipid transfer protein (PLTP) mediates phospholipid transfer processes between serum lipoproteins and is also a normal component of human tears. To study whether PLTP plays any functional role in tear fluid we investigated PLTP-deficient mice, applying functional and morphologic analyses under normal housing and experimentally induced dry eye conditions. Aqueous tear fluid production, corneal epithelial morphology, barrier function, and occludin expression were assessed. In mice with a full deficiency of functional PLTP enhanced corneal epithelial damage, increased corneal permeability to carboxyfluorescein, and decreased corneal epithelial occludin expression were shown. These pathologic signs were worsened by experimentally induced dry eye both in wild-type and PLTP knock-out mice. Deficiency in the production of tear PLTP in mice is accompanied by corneal epithelial damage, a feature that is typical in human dry eye syndrome (DES). To complement animal experiments we collected tear fluid from human dry eye patients as well as healthy control subjects. Increased tear fluid PLTP activity was observed among DES patients. In conclusion, the presence of PLTP in tear fluid appears to be essential for maintaining a healthy and functional ocular surface. Increased PLTP activity in human tear fluid in DES patients suggests an ocular surface protective role for this lipid transfer protein.


Subject(s)
Dry Eye Syndromes/metabolism , Epithelium, Corneal/metabolism , Phospholipid Transfer Proteins/metabolism , Tears/metabolism , Adult , Aged , Animals , Blotting, Western , Cell Membrane Permeability/physiology , Dry Eye Syndromes/pathology , Epithelium, Corneal/pathology , Female , Humans , Immunohistochemistry , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Middle Aged , Phospholipid Transfer Proteins/deficiency , Tears/chemistry , Tight Junctions/metabolism
3.
J Lipid Res ; 51(11): 3126-34, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20724654

ABSTRACT

In addition to circulation, where it transfers phospholipids between lipoprotein particles, phospholipid transfer protein (PLTP) was also identified as a component of normal tear fluid. The purpose of this study was to clarify the secretion route of tear fluid PLTP and elucidate possible interactions between PLTP and other tear fluid proteins. Human lacrimal gland samples were stained with monoclonal antibodies against PLTP. Heparin-Sepharose (H-S) affinity chromatography was used for specific PLTP binding, and coeluted proteins were identified with MALDI-TOF mass spectrometry or Western blot analysis. Immunoprecipitation assay and blotting with specific antibodies helped to identify and characterize PLTP-mucin interaction in tear fluid. Human tear fluid PLTP is secreted from the lacrimal gland. MALDI-TOF analysis of H-S fractions identified several candidate proteins, but protein-protein interaction assays revealed only ocular mucins as PLTP interaction partners. We suggest a dual role for PLTP in human tear fluid: (1) to scavenge lipophilic substances from ocular mucins and (2) to maintain the stability of the anterior tear lipid film. PLTP may also play a role in the development of ocular surface disease.


Subject(s)
Mucins/metabolism , Phospholipid Transfer Proteins/metabolism , Tears/metabolism , Animals , Cattle , Dry Eye Syndromes/metabolism , Dry Eye Syndromes/pathology , Heparin/metabolism , Humans , Lacrimal Apparatus/metabolism , Protein Binding , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Substrate Specificity
4.
J Nutr ; 140(8): 1462-8, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20554904

ABSTRACT

Dry eye is a common condition that can severely impair the quality of life. We aimed to find out whether oral sea buckthorn (SB) oil, containing (n-3) and (n-6) fatty acids and antioxidants, affects dry eye. In this double-blind, randomized, parallel trial, 20- to 75-y-old women and men experiencing dry eye symptoms consumed 2 g of SB or placebo oil daily for 3 mo from fall to winter. One hundred participants were recruited and 86 completed the study. Clinical dry eye tests and symptom follow-ups were performed. Tear film hyperosmolarity is a focal factor in dry eye. There was a general increase in the osmolarity from baseline to the end of the intervention. Compared with the placebo group, the increase was significantly less in the SB group when all participants were included [intention to treat (ITT), P = 0.04] and when only participants consuming the study products for at least 80% of the intervention days were included [per protocol (PP), P = 0.02]. The maximum intensities of redness and burning tended to be lower in the SB group. In the ITT participants, the group difference was significant for redness (P = 0.04) but not for burning (P = 0.05). In the PP participants, the group difference was significant for burning (P = 0.04) but not for redness (P = 0.11). In conclusion, SB oil attenuated the increase in tear film osmolarity during the cold season and positively affected the dry eye symptoms.


Subject(s)
Dry Eye Syndromes/drug therapy , Hippophae/chemistry , Plant Oils/administration & dosage , Tears/chemistry , Adult , Antioxidants/analysis , Double-Blind Method , Fatty Acids, Omega-3/analysis , Fatty Acids, Omega-6/analysis , Female , Humans , Male , Middle Aged , Osmolar Concentration , Placebos , Plant Oils/chemistry , Seeds/chemistry , Tears/drug effects
5.
Ocul Surf ; 18(4): 936-962, 2020 10.
Article in English | MEDLINE | ID: mdl-32504856

ABSTRACT

The mission of the Tear Film & Ocular Surface Society (TFOS) is to advance the research, literacy, and educational aspects of the scientific field of the tear film and ocular surface. Fundamental to fulfilling this mission is the TFOS Global Ambassador program. TFOS Ambassadors are dynamic and proactive experts, who help promote TFOS initiatives, such as presenting the conclusions and recommendations of the recent TFOS DEWS II™, throughout the world. They also identify unmet needs, and propose future clinical and scientific solutions, for management of ocular surface diseases in their countries. This meeting report addresses such needs and solutions for 25 European countries, as detailed in the TFOS European Ambassador meeting in Rome, Italy, in September 2019.


Subject(s)
Dry Eye Syndromes , Congresses as Topic , Europe , Eye , Humans , Italy , Tears
6.
J Interferon Cytokine Res ; 22(6): 641-51, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12162874

ABSTRACT

We investigated the expression kinetics of several cytokines in trigeminal ganglia (TG) and in brains of BALB/c mice during the course of ocular herpes simplex virus type 1 (HSV-1) infection. All mice recovered from the infection within 2 weeks. The quantitative rapid real-time RT-PCR method was used to analyze interleukin-4 (IL-4), interferon-gamma (IFN-gamma), IL-12p35, IL-12p40, and the recently described IL-23 (p19) mRNA in TG, brain, and splenocyte samples. In TG, we found elevated expression of mRNA for IL-23 (p19) from early acute infection (day 3) to the beginning of the latent phase (day 14). The increase was not detected in brain or in the spleen. IL-4 expression occurred in both TG and brain from the beginning of the experiment to the latent phase. During the latent phase (days 14 and 31), IL-4 expression was significantly elevated in the brain when compared with the uninfected controls (p < 0.05). Considerable expression of IFN-gamma mRNA was detected in TG of mice during acute HSV-1 infection. The expression of IL-23 was detected also in the brains of the mice, even though no significant changes were found during the acute HSV-1 infection. This is, to our knowledge, the first report to show elevated expression of IL-23 (p19) mRNA (p < 0.05) during viral infection in TG of mice.


Subject(s)
Herpes Simplex/metabolism , Interleukins/metabolism , Trigeminal Ganglion/metabolism , Up-Regulation , Acute Disease , Animals , Brain/metabolism , Brain/virology , Chick Embryo , Eye/metabolism , Eye/virology , Female , Herpes Simplex/genetics , Interferon-gamma/metabolism , Interleukin-12/metabolism , Interleukin-12 Subunit p35 , Interleukin-12 Subunit p40 , Interleukin-23 , Interleukin-23 Subunit p19 , Interleukin-4/metabolism , Interleukins/genetics , Mice , Mice, Inbred BALB C , Protein Subunits/metabolism , RNA, Messenger/metabolism , Trigeminal Ganglion/virology
7.
Cornea ; 30(9): 1013-9, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21832964

ABSTRACT

PURPOSE: Evaporative dry eye is associated with meibomian gland dysfunction and abnormalities of the tear film lipids. Dry eye is known to be affected positively by intake of linoleic and γ-linolenic acids and n-3 fatty acids. Oral sea buckthorn (Hippophaë rhamnoides) (SB) oil, which contains linoleic and α-linolenic acids and antioxidants, has shown beneficial effects on dry eye. The objective was to investigate whether supplementation with SB oil affects the composition of the tear film fatty acids in individuals reporting dry eye. METHODS: One hundred participants were randomized to this parallel, double-blind, placebo-controlled study, which 86 of them completed. The participants daily consumed 2 g of SB or placebo oil for 3 months. Tear film samples were collected at the beginning, during, and at the end of the intervention and 1 to 2 months later. Tear film fatty acids were analyzed as methyl esters by gas chromatography. RESULTS: There were no group differences in the changes in fatty acid proportions during the intervention (branched-chain fatty acids: P = 0.49, saturated fatty acids: P = 0.59, monounsaturated fatty acids: P = 0.53, and polyunsaturated fatty acids: P = 0.16). CONCLUSIONS: The results indicate that the positive effects of SB oil on dry eye are not mediated through direct effects on the tear film fatty acids. Carotenoids and tocopherols in the oil or eicosanoids produced from the fatty acids of the oil may have a positive effect on inflammation and differentiation of the meibomian gland cells.


Subject(s)
Dry Eye Syndromes/drug therapy , Fatty Acids/metabolism , Hippophae/chemistry , Phytotherapy , Plant Oils/therapeutic use , Tears/metabolism , Administration, Oral , Adult , Aged , Capsules , Chromatography, Gas , Double-Blind Method , Dry Eye Syndromes/metabolism , Female , Humans , Male , Middle Aged , Plant Oils/administration & dosage , Plant Oils/chemistry , Young Adult
8.
Biochemistry ; 46(5): 1312-9, 2007 Feb 06.
Article in English | MEDLINE | ID: mdl-17260960

ABSTRACT

In circulation the phospholipid transfer protein (PLTP) facilitates the transfer of phospholipid-rich surface components from postlipolytic chylomicrons and very low density lipoproteins (VLDL) to HDL and thereby regulates plasma HDL levels. To study the molecular mechanisms involved in PLTP-mediated lipid transfer, we studied the interfacial properties of PLTP using Langmuir phospholipid monolayers and asymmetrical flow field-flow fractionation (AsFlFFF) to follow the transfer of 14C-labeled phospholipids and [35S]PLTP between lipid vesicles and HDL particles. The AsFlFFF method was also used to determine the sizes of spherical and discoidal HDL particles and small unilamellar lipid vesicles. In Langmuir monolayer studies high-activity (HA) and low-activity (LA) forms of PLTP associated with fluid phosphatidylcholine monolayers spread at the air/buffer interphase. Both forms also mediated desorption of [14C]dipalmitoylphosphatidylcholine (DPPC) from the phospholipid monolayer into the buffer phase, even when it contained no physiological acceptor such as HDL. After the addition of HDL3 to the buffer, HA-PLTP caused enhanced lipid transfer to them. The particle diameter of HA-PLTP was approximately 6 nm and that of HDL3 approximately 8 nm as determined by AsFlFFF analysis. Using this method, it could be demonstrated that in the presence of HA-PLTP, but not LA-PLTP, [14C]DPPC was transferred from small unilamellar vesicles (SUV) to acceptor HDL3 molecules. Concomitantly, [35S]-HA-PLTP was transferred from the donor to acceptor, and this transfer was not observed for its low-activity counterpart. These observations suggest that HA-PLTP is capable of transferring lipids by a shuttle mechanism and that formation of a ternary complex between PLTP, acceptor, and donor particles is not necessary for phospholipid transfer.


Subject(s)
Lipid Metabolism , Phospholipid Transfer Proteins/metabolism , Phospholipids/metabolism , 1,2-Dipalmitoylphosphatidylcholine/metabolism , Carbon Radioisotopes , Humans , Lipoproteins, HDL/metabolism , Liposomes/metabolism , Particle Size , Phospholipid Transfer Proteins/chemistry , Sulfur Radioisotopes
9.
Biochemistry ; 44(22): 8111-6, 2005 Jun 07.
Article in English | MEDLINE | ID: mdl-15924430

ABSTRACT

The human tear fluid film consists of a superficial lipid layer, an aqueous middle layer, and a hydrated mucin layer located next to the corneal epithelium. The superficial lipid layer protects the eye from drying and is composed of polar and neutral lipids provided by the meibomian glands. Excess accumulation of lipids in the tear film may lead to drying of the corneal epithelium. In the circulation, phospholipid transfer protein (PLTP) and cholesteryl ester transfer protein (CETP) mediate lipid transfers. To gain insight into the formation of tear film, we investigated whether PLTP and CETP are present in human tear fluid. Tear fluid samples were collected with microcapillaries. The presence of PLTP and CETP was studied in tear fluid by Western blotting, and the PLTP concentration was determined by ELISA. The activities of the enzymes were determined by specific lipid transfer assays. Size-exclusion and heparin-affinity chromatography assessed the molecular form of PLTP. PLTP is present in tear fluid, whereas CETP is not. Quantitative assessment of PLTP by ELISA indicated that the PLTP concentration in tear fluid, 10.9 +/- 2.4 microg/mL, is about 2-fold higher than that in human plasma. PLTP-facilitated phospholipid transfer activity in tears, 15.1 +/- 1.8 micromol mL(-)(1) h(-)(1), was also significantly higher than that measured in plasma. Inactivation of PLTP by heat treatment (+58 degrees C, 60 min) or immunoinhibition abolished the phospholipid transfer activity in tear fluid. Size-exclusion chromatography of tear fluid indicated that PLTP eluted in a position corresponding to a size of 160-170 kDa. Tear fluid PLTP was quantitatively bound to Heparin-Sepharose and could be eluted as a single peak by 0.5 M NaCl. These data indicate that human tear fluid contains catalytically active PLTP protein, which resembles the active form of PLTP present in plasma. The results suggest that PLTP may play a role in the formation of the tear film by supporting phospholipid transfer.


Subject(s)
Membrane Proteins/isolation & purification , Phospholipid Transfer Proteins/isolation & purification , Tears/chemistry , Apolipoprotein A-I/chemistry , Apolipoproteins E/chemistry , Biological Transport, Active , Blotting, Western/methods , Carrier Proteins/chemistry , Carrier Proteins/immunology , Carrier Proteins/metabolism , Cholesterol Ester Transfer Proteins , Cholesterol Esters/metabolism , Chromatography, Affinity , Chromatography, Gel , Glycoproteins/chemistry , Glycoproteins/immunology , Glycoproteins/metabolism , Heparin/metabolism , Hot Temperature , Humans , Immune Sera/chemistry , Membrane Proteins/antagonists & inhibitors , Membrane Proteins/blood , Membrane Proteins/metabolism , Phospholipid Transfer Proteins/antagonists & inhibitors , Phospholipid Transfer Proteins/blood , Phospholipid Transfer Proteins/metabolism , Phospholipids/metabolism , Sepharose/analogs & derivatives , Sepharose/metabolism , Tears/enzymology , Tears/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL