Background
Activation of innate immunity plays a key role in determining the outcome of an infection. Here, we investigated whether Toll-like receptors (TLRs) are involved in retinal innate response and explored the prophylactic use of TLR2 ligand in preventing bacterial endophthalmitis.
Methods
C57BL/6 (B6) mice were given intravitreal injections of Pam3Cys, a synthetic ligand of TLR2, or vehicle (PBS) 24 h prior to S. aureus (SA) inoculation. The severity of endophthalmitis was graded by slit lamp, electroretinography (ERG), histological examinations and determination of bacterial load in the retina. The expression of cytokines/chemokines and cathelicidin-related antimicrobial peptide (CRAMP) was assessed by ELISA and Western blot respectively.
Results
Intravitreal injections of Pam3Cys up-regulated TLR2 expression in the B6 retina and Pam3Cys pretreatment significantly improved the outcome of SA endophthalmitis, preserved retinal structural integrity and maintained visual function assessed with ERG in B6 mice. Furthermore, Pam3Cys pretreatment activated retinal microglia cells, induced the expression of CRAMP, and remarkably reduced the bacterial load.
Conclusions
This is the first report that highlights the existence and role of TLR2 in retinal innate immune response to SA infection and suggests that modulation of TLR activation provides a novel prophylactic approach to prevent bacterial endophthalmitis.
Chronic intravitreous infusion of FA preserves ONL cell morphology and ERG a- and b-wave amplitudes and reduces retinal neuroinflammation in S334ter rats. Based on these findings, the synthetic corticosteroid FA may promise a therapeutic role in patients with retinal degeneration.
Chronic intravitreal infusion of FA is neuroprotective in RCS rats, preserves ONL morphology and ERG amplitudes and reduces retinal neuroinflammation. These findings may have a therapeutic role in human photoreceptor cell degenerations.
Retinal sensitivity to electrical stimulation was preserved in animals treated with chronic intravitreous infusion of CNTF. These data suggest that CNTF-mediated retinal neuroprotection may be a novel therapy that can lower stimulus thresholds in patients about to undergo retinal prosthesis implantation. Furthermore, it may maintain the long-term efficacy of these devices in patients.
To determine the association between multifocal electroretinogram (mfERG) abnormalities and macular lesions, as shown by retinal photography and optical coherence tomography (OCT), in a 3-generation family with vitelliform macular dystrophy. Methods: Five family members were examined using OCT, mfERG, and retinal photography. To localize mfERG abnormalities in relation to retinal findings, we overlaid the mfERG trace arrays on the retinal images and aligned the mfERGs and OCT images in the 180°m eridian. Results: Family members had typical macular lesions, normal full-field ERGs, and reduced electro-oculogram light-dark ratios. The OCT images demonstrated variable lesion severity. Some individuals with good vision and normal-appearing fundi showed OCT abnormalities of the choroid and retinal pigment epithelium. The overlay technique revealed that the depressed mfERGs corresponded with the lesions detected by OCT and retinal photography. The latencies of mfERG components in the 2 central stimulus rings in our patients were often prolonged. Conclusions: The mfERG abnormalities matched the localization of the macular lesions in our patients. The latencies of the mfERG N1 and P1 components in the first 2 concentric stimulus rings were often significantly (Ͼ2 SDs) delayed, an observation that has not been previously reported, to our knowledge.
SD-OCT, microperimetry, and mfERG can be used to help diagnose, stratify traumatic severity, and follow structural and functional progression over time in patients with Berlin's edema. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:114-121.].
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