tear secretion
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2022 ◽  
Vol 23 (2) ◽  
pp. 664
Author(s):  
Takahiro Hirabayashi ◽  
Junko Shibato ◽  
Ai Kimura ◽  
Michio Yamashita ◽  
Fumiko Takenoya ◽  
...  

Dry eye disease (DED) is caused by a reduction in the volume or quality of tears. The prevalence of DED is estimated to be 100 million in the developed world. As aging is a risk factor for DED, the prevalence of DED is expected to grow at a rapid pace in aging populations, thus creating an increased need for new therapies. This review summarizes DED medications currently in clinical use. Most current medications for DED focus on stimulating tear secretion, mucin secretion, or suppressing inflammation, rather than simply replenishing the ocular surface with moisture to improve symptoms. We recently reported that the neuropeptide PACAP (pituitary adenylate cyclase-activating polypeptide) induces tear secretion and suppresses corneal injury caused by a reduction in tears. Moreover, it has been reported that a PACAP in water and a 0.9% saline solution at +4 °C showed high stability and achieved 80–90% effectiveness after 2 weeks of treatment. These results reveal PACAP as a candidate DED medication. Further research on the clinical applications of PACAP in DED is necessary.


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Chao Sun ◽  
Xiaofan Chen ◽  
Yanming Huang ◽  
Huan Zou ◽  
Wei Fan ◽  
...  

Abstract Background To study the effects of aerobic exercise (AE) on tear secretion and tear film stability in dry eye patients. Methods This study consisted of two parts, each part included 3 groups, namely dry eye without AE group, dry eye with AE group and pre-clinical dry eye with AE group. In part 1, we studied the variations of Schirmer I test and six tear compositions before and after AE (34 eyes in each group). In part 2, we studied the variations of tear meniscus height, first and average non-invasive tear breakup time (F-NITBUT and A-NITBUT), lipid layer thickness, number of incomplete and complete blinks, partial blink rate (PBR) and visual acuity before and after AE (30 eyes in each group). Results In dry eye with AE group, Schirmer I test at 0 min after AE increased significantly compared to baseline (P < 0.001), the oxidative stress marker 8-hydroxy-2′-deoxyguanosine after AE decreased significantly compared to baseline (P = 0.035, P = 0.045), F-NITBUT and A-NITBUT after AE prolonged significantly compared to baseline (P < 0.001, P = 0.007, P = 0.036; P < 0.001, P = 0.001, P = 0.044), number of incomplete blinks and PBR at 10 min after AE decreased significantly compared to baseline (P < 0.001; P < 0.001) while number of complete blinks increased significantly (P < 0.001). Besides, significant differences were also found between dry eye with AE group and dry eye without AE group at all above corresponding time point (P < 0.05). Conclusion AE promotes tear secretion and improves tear film stability in dry eye patients. AE may be a potential treatment for dry eye. Trial registration Chinese Clinical Trial Registry, ChiCTR2000038673. Registered 27 September 2020,


Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1801
Author(s):  
Yi-Zhou Chen ◽  
Zhi-Yu Chen ◽  
Yu-Jun Tang ◽  
Cheng-Han Tsai ◽  
Yu-Lun Chuang ◽  
...  

Dry eye syndrome (DES) is a common ophthalmological disease that decreases tear secretion and causes dryness, photophobia, pain, severe corneal rupture, and even blindness. Ocular and lacrimal gland inflammation is one of the pathological mechanisms underlying DES. Therefore, effective suppression of inflammation is a crucial strategy for the treatment of DES. Lutein, commonly found in healthy foods, has anti-inflammatory effects in corneal or retina-related cells and may be a potential therapy for DES. The addition of lutein to artificial tears (AT) as an eye-drop formulation for DES treatment in a mouse model was studied in the present work. Polyvinyl alcohol (PVA) was used as a thickener to increase the viscosity of eye drops to prolong drug retention on the ocular surface. A WST-8 assay in human corneal epithelial cells (HCE-2) showed that a concentration of <5 μM lutein (L5) and <1% PVA (P1) maintained the cell viability at 80%. A real-time PCR showed that the inflamed human corneal epithelial cells (HCECs) cocultured with L5P1 had downregulated expression of inflammatory genes such as IL-1β, IL-6, and TNF-α. In a benzalkonium chloride- (BAC) induced DES mouse model, AT/L5P1 could repair damaged corneas, elevate tear secretion, increase the number of goblet cells, and inhibit the production of inflammatory cytokines, such as IL-1β, IL-6, and TNF-α, in the cornea. In conclusion, we demonstrate that lutein/PVA as eye drops could prolong the drug ocular retention time and effectively to decrease inflammation in DES mice. Therefore, lutein, obtained from eye drops, has a potential therapeutic role for DES.


2021 ◽  
Author(s):  
Xin Wang ◽  
Xiaojing Fan ◽  
Yaying Wu ◽  
Yujie Mou ◽  
Jinjin Min ◽  
...  

Abstract This study was desgined to find a reliable and convenient indicator (a modified Schirmer test) to improve the accuracy of assessing tear secretion and diagnosing dry eye. This is a prospective continuous study on 180 volunteers. Schirmer test I without anesthesia was performed once on both eyes to determine the value of normal Schirmer test. The values of tear secretion were recorded in each minute. Examined individuals also underwent other examinations: the standard patient evaluation of eye dryness (SPEED), the Ocular Surface Disease Index (OSDI), fluorescein stain, tear film breakup time (BUT), and Meibomian gland (MG)grading. The participants were divided into two groups: dry eye (DE) groupand non-dry eye (ND) group. The mean age was 39.41±14.05 years in DE group and 37.62±13.17 in ND group. The value of 2-minute Schirmer test, rear 3-minute Schirmer test, rear 4-minute Schirmer test and 5-minute Schirmer test was 5.36±4.63, 5.57±2.11, 7.21±4.13 and 10.93±6.30 respectively in DE group. And these indicators was 8.25±6.80, 2.73±2.31, 7.36±3.42, 11.84±6.16 in ND group. The rear 4-minute ST has significant correlation with OSDI and SPEED in DE group (r =-0.242/-0.183) and in ND gruop(r =-0.316 /-0.373). Meanwhile, rear 4-minute ST had stronger connection with fBUT(r =0.159) and MG (r =-0.162) in DE gruop. And rear 4-minute ST also had higher accuracy in diagnosing severe dry eye and borderline dry eye.The rear 4-minute Schirmer test may be a supplement indicator in assessing tear secretion and diagnosing dry eye.


Nutrients ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 2536
Author(s):  
Masayuki Yamaga ◽  
Toshihiro Imada ◽  
Hiroko Tani ◽  
Shigeru Nakamura ◽  
Ayanori Yamaki ◽  
...  

Dry eye is a multifactorial disease characterized by ocular discomfort and visual impairment. Our previous studies have shown that royal jelly (RJ) has restored the capacity for tear secretion by modulating muscarinic calcium signaling. RJ contains acetylcholine, which is a major cholinergic neurotransmitter, and a unique set of fatty acids with C 8 to 12 chains, which are expected to be associated with health benefits. The purpose of the present study was to investigate the active components involved in tear secretion capacity, focusing on acetylcholine and fatty acids in RJ. Using the stress-induced dry-eye model mice, it was confirmed that acetylcholine with three fatty acids (10-hydroxydecanoic acid, 8-hydroxyoctanoic acid, and (R)-3,10-dihydroxydecanoic acid) was essential for tear secretion. In ex vivo Ca2+ imaging, these three fatty acids suppressed the decrease in intracellular modulation of Ca2+ in the lacrimal gland by acetylcholine when treated with acetylcholinesterase, indicating that the specific type of RJ fatty acids contributed to the stability of acetylcholine. To our knowledge, this study is the first to confirm that a specific compound combination is important for the pharmacological activities of RJ. Our results elucidate the active molecules and efficacy mechanisms of RJ.


Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1857
Author(s):  
Young-Ho Jung ◽  
Jin-Suk Ryu ◽  
Chang-Ho Yoon ◽  
Mee-Kum Kim

We investigated whether aging-dependent changes in dendritic cell (DC) distributions are distinct in autoimmune dry eye compared with an aging-related murine model. Corneal staining and tear secretion were evaluated in young and aged C57BL/6 (B6) and NOD.B10.H2b mice (NOD). In the corneolimbus, lacrimal gland (LG), and mesenteric lymph node (MLN), CD11b− and CD11b+ DCs, CD103+ DCs and MHC-IIhi B cells were compared between young and aged B6 and NOD mice. With increased corneal staining, tear secretion decreased in both aged B6 and NOD mice (p < 0.001). In both aged B6 and NOD mice, the percentages of corneolimbal CD11b+ DCs were higher (p < 0.05) than those in young mice. While, the percentages of lymph nodal CD103+ DCs were higher in aged B6 and NOD mice (p < 0.05), the percentages of corneolimbal CD103+ DCs were only higher in aged NOD mice (p < 0.05). In aged NOD mice, the proportions of lacrimal glandial and lymph nodal MHC-IIhi B cells were also higher than those in young mice (p < 0.05). It indicates that corneolimbal or lacrimal glandial distribution of CD103+ DCs or MHC-IIhi B cells may be distinct in aged autoimmune dry eye models compared to those in aged immune competent murine models.


Medicina ◽  
2021 ◽  
Vol 57 (6) ◽  
pp. 608
Author(s):  
Yong-Jae Lee ◽  
Han-Sol Choi ◽  
Seong-Jun Park ◽  
Hae-Jung Sun ◽  
Sun-Young Jang

The aim of the present study was to report two cases of refractory dry eye syndrome (DES) after transconjunctival excision of the palpebral lobe of the lacrimal gland. A 25-year-old female patient with a chief complaint of a palpable mass in both upper eyelids visited our medical center. Preoperative orbital computer tomography showed high-attenuation lesions in both lacrimal glands. Incisional biopsy of the lacrimal gland palpebral lobe via transconjunctival incision was performed in January 2019. At 1 month after the biopsy, a lack of tears and persistent corneal erosions were found in both eyes. Artificial tears, punctal occlusion, autologous serum eye drops, and therapeutic contact lenses were applied in an attempt to control the dry eye symptoms. The patient continues to suffer from intractable DES at 2.5 years after the procedure. The second case involved a 52-year-old female patient who visited our medical center with a chief complaint of a palpable mass in both upper eyelids. Bilateral orbital tumors were diagnosed with preoperative magnetic resonance imaging. An incisional biopsy of the lacrimal gland was performed. Immunoglobulin G4-related dacryoadenitis was confirmed through lacrimal palpebral lobe incisional biopsy. Intractable DES and corneal erosion of her left eye persisted thereafter. A transconjunctival incision is an effective approach for minimizing postoperative scars and is suitable for the biopsy of tumors that are visible through the conjunctiva. After a biopsy of the palpebral lobe of the main lacrimal glands, the secretion of reflex tears decreases due to damage to the secreting ducts of the main lacrimal glands. However, total tear secretion can be maintained by basal tear secretion from the accessory lacrimal glands. In this report, we describe two cases of refractory DES due to decreased total tear secretion, although only the palpebral lobes of the main lacrimal glands were biopsied.


2021 ◽  
Vol 22 (11) ◽  
pp. 6133
Author(s):  
Aytan Musayeva ◽  
Subao Jiang ◽  
Yue Ruan ◽  
Jenia Kouchek Zadeh ◽  
Panagiotis Chronopoulos ◽  
...  

The parasympathetic nervous system is critically involved in the regulation of tear secretion by activating muscarinic acetylcholine receptors. Hence, various animal models targeting parasympathetic signaling have been developed to induce dry eye disease (DED). However, the muscarinic receptor subtype (M1–M5) mediating tear secretion remains to be determined. This study was conducted to test the hypothesis that the M3 receptor subtype regulates tear secretion and to evaluate the ocular surface phenotype of mice with targeted disruption of the M3 receptor (M3R−/−). The experimental techniques included quantification of tear production, fluorescein staining of the ocular surface, environmental scanning electron microscopy, assessment of proliferating cells in the corneal epithelium and of goblet cells in the conjunctiva, quantification of mRNA for inflammatory cytokines and prooxidant redox enzymes and quantification of reactive oxygen species. Tear volume was reduced in M3R−/− mice compared to age-matched controls at the age of 3 months and 15 months, respectively. This was associated with mild corneal epitheliopathy in the 15-month-old but not in the 3-month-old M3R−/− mice. M3R−/− mice at the age of 15 months also displayed changes in corneal epithelial cell texture, reduced conjunctival goblet cell density, oxidative stress and elevated mRNA expression levels for inflammatory cytokines and prooxidant redox enzymes. The findings suggest that the M3 receptor plays a pivotal role in tear production and its absence leads to ocular surface changes typical for DED at advanced age.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chang Ho Yoon ◽  
Jin Suk Ryu ◽  
Jayoon Moon ◽  
Mee Kum Kim

Abstract Background While aging is a potent risk factor of dry eye disease, age-related gut dysbiosis is associated with inflammation and chronic geriatric diseases. Emerging evidence have demonstrated that gut dysbiosis contributes to the pathophysiology or exacerbation of ocular diseases including dry eye disease. However, the relationship between aging-related changes in gut microbiota and dry eye disease has not been elucidated. In this pilot study, we investigated the association between aging-dependent microbiome changes and dry eye severity in C57BL/6 male mice. Results Eight-week-old (8 W, n = 15), one-year-old (1Y, n = 10), and two-year-old (2Y, n = 8) C57BL/6 male mice were used. Dry eye severity was assessed by corneal staining scores and tear secretion. Bacterial genomic 16 s rRNA from feces was analyzed. Main outcomes were microbiome compositional differences among the groups and their correlation to dry eye severity. In aged mice (1Y and 2Y), corneal staining increased and tear secretion decreased with statistical significance. Gut microbiome α-diversity was not different among the groups. However, β-diversity was significantly different among the groups. In univariate analysis, phylum Firmicutes, Proteobacteria, and Cyanobacteria, Firmicutes/Bacteroidetes ratio, and genus Alistipes, Bacteroides, Prevotella, Paraprevotella, and Helicobacter were significantly related to dry eye severity. After adjustment of age, multivariate analysis revealed phylum Proteobacteria, Firmicutes/Bacteroidetes ratio, and genus Lactobacillus, Alistipes, Prevotella, Paraprevotella, and Helicobacter to be significantly associated with dry eye severity. Conclusions Our pilot study suggests that aging-dependent changes in microbiome composition are related to severity of dry eye signs in C57BL/6 male mice.


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