Concentration gradient of noradrenaline from the periphery to the centre of the cornea - A clue to its origin

Figueira, Luís; Ferreira, Carla; Janeiro, Catarina; Serrão, Paula; Falcão‐Reis, Fernando; Moura, Daniel

doi:10.1016/j.exer.2018.01.008

Cited by 9 publications

(5 citation statements)

References 39 publications

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“…The higher levels of dopamine observed in the tear fluid than in the plasma could be attributed to the low level of plasma dopamine observed in circulation – derived from biosynthesis in the gastrointestinal tract[26] – or owing to the possibility of an ocular synthesis mechanism existing for dopamine as has been suggested in a very recent report. [27] The mean plasma dopamine level in the current study is 97.2 ± 11.80 pg/ml using ELISA which is comparable to range reported by other studies. Ambade et al .…”

Section: Discussionsupporting

confidence: 90%

Dopamine levels in human tear fluid

Sharma

Acharya

Nair

et al. 2019

Indian J Ophthalmol

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Purpose:To determine the levels of dopamine in tear fluid and demonstrate the use of tear fluid as a non-invasive source for dopamine measurements in humans.Methods:The study cohort included 30 clinically healthy individuals without any pre-existing ocular or systemic conditions. Matched tear fluid (using Schirmer's strips and capillary tubes) and plasma were collected from the subjects. Dopamine levels were evaluated using direct competitive chemiluminescent enzyme-linked immunosorbent assay (ELISA), dopamine kit (Cloud Clone Corp, TX, USA).Results:Significantly higher dopamine levels were found in the tear fluid compared to plasma in the study subjects. The level of dopamine was 97.2 ± 11.80 pg/ml (mean ± SEM), 279 ± 14.8 pg/ml (mean ± SEM), and 470.4 ± 37.64 pg/ml (mean ± SEM) in the plasma and in the tears collected using Schirmer's strips and capillary tubes, respectively.Conclusion:Dopamine was detectable in all the tear fluid samples tested and was also found to be at a higher concentration than in plasma samples. Tear fluid can be used as a non-invasive sample source to monitor dopamine levels.

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Section: Discussionsupporting

confidence: 90%

Dopamine levels in human tear fluid

Sharma

Acharya

Nair

et al. 2019

Indian J Ophthalmol

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“…8 ). Since corneal NA derives mostly from nerves, 46 , 47 we conclude that NA secretion is a direct consequence of SNS activation.…”

Section: Discussionmentioning

confidence: 71%

“…The role of SNS in corneal inflammation has been studied before, and it is generally thought it is mediated by noradrenaline. 46 , 47 Specifically, it is known that after corneal injury, the SNS promotes leukocyte recruitment and inflammation. This has clinical implications, because it results in delayed wound healing, 20 promotion of pain through sensitization of sensory terminals, 50 and persistent inflammation in infectious keratitis.…”

Section: Discussionmentioning

confidence: 99%

A Hypothalamic-Controlled Neural Reflex Promotes Corneal Inflammation

Vitar

Fonteyne

Chaabane³

et al. 2021

Invest. Ophthalmol. Vis. Sci.

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Purpose To test whether an acute corneal injury activates a proinflammatory reflex, involving corneal sensory nerves expressing substance P (SP), the hypothalamus, and the sympathetic nervous system. Methods C57BL6/N (wild-type [WT]) and SP-depleted B6.Cg-Tac1tm1Bbm/J (TAC1-KO) mice underwent bilateral corneal alkali burn. One group of WT mice received oxybuprocaine before alkali burn. One hour later, hypothalamic neuronal activity was assessed in vivo by magnetic resonance imaging and ex vivo by cFOS staining. Some animals were followed up for 14 days to evaluate corneal transparency and inflammation. Tyrosine hydroxylase (TH), neurokinin 1 receptor (NK1R), and neuronal nitric oxide synthase (nNOS) expression was assessed in brain sections. Sympathetic neuron activation was evaluated in the superior cervical ganglion (SCG). CD45 + leukocytes were quantified in whole-mounted corneas. Noradrenaline (NA) was evaluated in the cornea and bone marrow. Results Alkali burn acutely induced neuronal activation in the trigeminal ganglion, paraventricular hypothalamus, and lateral hypothalamic area (PVH and LHA), which was significantly lower in TAC1-KO mice ( P < 0.05). Oxybuprocaine application similarly reduced neuronal activation ( P < 0.05). TAC1-KO mice showed a reduced number of cFOS + /NK1R + /TH + presympathetic neurons ( P < 0.05) paralleled by higher nNOS expression ( P < 0.05) in both PVH and LHA. A decrease in activated sympathetic neurons in the SCG and NA levels in both cornea/bone marrow and reduced corneal leukocyte infiltration ( P < 0.05) in TAC1-KO mice were found. Finally, 14 days after injury, TAC1-KO mice showed reduced corneal opacity and inflammation ( P < 0.05). Conclusions Our findings suggest that stimulation of corneal sensory nerves containing SP activates presympathetic neurons located in the PVH and LHA, leading to sympathetic activation, peripheral release of NA, and corneal inflammation.

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“…The integration of DOPA, a mussel‐inspired peptide, mediates the wet adhesion in this system. Interestingly, given DOPA's role as a nerve‐releasing neurotransmitter, [ 25 ] a DOPA‐containing hydrogel can possibly promote corneal innervation. In this hydrogel system, DOPA residues were linked to hyaluronic acid methacrylate (HAMA) (Figure S1, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Photocurable and Temperature‐Sensitive Bioadhesive Hydrogels for Sutureless Sealing of Full‐Thickness Corneal Wounds

Wang,

Zhao,

et al. 2023

Small Methods

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Penetrating corneal wounds can cause severe vision impairment and require prompt intervention to restore globe integrity and minimize the risk of infection. Tissue adhesives have emerged as a promising alternative to suturing for mitigating postoperative complications. However, conventional water‐soluble adhesives suffer formidable challenges in sealing penetrating corneal wounds due to dilution or loss in a moist environment. Inspired by the robust adhesion of mussels in aquatic conditions, an injectable photocurable bioadhesive hydrogel (referred to as F20HD5) composed of polyether F127 diacrylate and dopamine‐modified hyaluronic acid methacrylate is developed for sutureless closure of corneal full‐thickness wounds. F20HD5 exhibits high transparency, wound‐sealing ability, proper viscosity, biodegradability, and excellent biocompatibility. It allows in situ cross‐linking via visible light, thereby providing sufficient mechanical strength and adhesiveness. In vivo, the adhesive hydrogel effectively closed penetrating linear corneal incisions and corneal injuries with minimal tissue loss in rabbits. During the 56‐day follow‐up, the hydrogel facilitates the repair of the injured corneas, resulting in more symmetrical curvatures and less scarring in distinction to the untreated control. Thus, bioinspired hydrogel holds promise as an effective adhesive for sealing full‐thickness corneal wounds.

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Concentration gradient of noradrenaline from the periphery to the centre of the cornea - A clue to its origin

Cited by 9 publications

References 39 publications

Dopamine levels in human tear fluid

Dopamine levels in human tear fluid

A Hypothalamic-Controlled Neural Reflex Promotes Corneal Inflammation

Photocurable and Temperature‐Sensitive Bioadhesive Hydrogels for Sutureless Sealing of Full‐Thickness Corneal Wounds

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