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Updated: Oct 9, 2026
Characterization of a Novel Human Organotypic Retinal Culture Technique
Published on: June 9, 2021
Intravitreal invading cells contribute to vitreal cytokine milieu in proliferative vitreoretinopathy
I A El-Ghrably1, H S Dua, G M Orr
1Larry A Donoso Laboratory for Eye Research, Department of Ophthalmology, University of Nottingham, UK.
Aim:
To examine the contribution of infiltrating cells in the local production of cytokines within the vitreous of patients with proliferative vitreoretinopathy (PVR).
Methods:
The presence of mRNA coding for IL-6, IL-8, IL-1beta, IL-1alpha, TNFalpha, IFNgamma, IL-12, and HPRT was investigated in 25 vitreous samples from patients with PVR, 11 vitreous samples from patients with retinal detachment (RD) not complicated by PVR, and 10 vitreous samples from patients with macular hole (MH). A quantitative reverse transcriptase polymerase chain reaction (RT-PCR) using an internal competitor was used to investigate these samples. From these samples, 15 PVR, 8 RD, and 8 MH were analysed for the protein levels of the same cytokines using enzyme linked immunosorbent assay (ELISA). Spearman correlation was used to test any association between mRNA and cytokine protein levels, as an indicator of the contribution these cells make to the intravitreal cytokine milieu.
Results:
A strong correlation was found between mRNA and their respective cytokine levels (protein products) for IL-6, IL-8, IL-1beta, IL-1alpha, TNFalpha, IFNgamma (Spearman r = 0.83, 0.73, 0.67, 0.91, 0.73, and 0.73 respectively), but not for IL-12. The median levels of IL-6, IL-8, IL-1beta, and IFNgamma mRNA and their respective cytokines were significantly higher (p <0.05) in patients with PVR than in those with macular hole. There was no statistically significant difference in the median levels of IL-1alpha mRNA between PVR and MH but the cytokine IL-1alpha was detected at a significantly higher level in PVR compared with MH patients. Between PVR and RD patients, there was no statistically significant difference in mRNA levels for all the investigated cytokines (p >0.05) except for IL-6 where there was a statistical significance (p= 0.038). In contrast, the median levels of IL-6, IL-8, and IL-1beta cytokines were significantly higher (p <0.05) in patients with PVR than in those with RD, whereas for IL-1alpha and IFNgamma no significant statistical difference was detected between PVR and RD patients (p >0.05). When results of RD and MH patients were compared, a statistical difference was only detected in mRNA levels of INFgamma (p = 0.008). However, no difference was detected for INFgamma (protein product) or for any of the other cytokines between RD and MH patients.
Conclusion:
Levels of both protein and mRNA encoding IL-6, IL-8, IL-1beta, and IFNgamma is significantly increased in vitreous samples from patients with PVR. The strong correlation between ELISA detectable cytokines (protein products) and their respective mRNA levels suggest that intravitreal, invasive cells are the major source of these cytokines, with the exception of IL-12. Cells invading the vitreous do not appear to locally produce IL-12 mRNA. This would appear to implicate cells peripheral to the vitreal mass as the major source of this cytokine.
Insights
In proliferative vitreoretinopathy (PVR), infiltrating cells significantly increase local production of cytokines like IL-6, IL-8, IL-1beta, and IFNgamma. These cells are the primary source of these cytokines in the vitreous, except for IL-12.
Area of Science:
- Ophthalmology
- Immunology
- Molecular Biology
Background:
- Proliferative vitreoretinopathy (PVR) is a severe complication of retinal detachment.
- Intraocular inflammation and cytokine production play a critical role in PVR pathogenesis.
- The source of cytokines within the vitreous humor in PVR remains incompletely understood.
Purpose of the Study:
- To investigate the contribution of infiltrating cells to local cytokine production in the vitreous of patients with PVR.
- To quantify mRNA and protein levels of key inflammatory cytokines in vitreous samples.
- To correlate cellular infiltration with cytokine expression profiles in PVR.
Main Methods:
- Vitreous samples were collected from patients with PVR, retinal detachment (RD), and macular hole (MH).
- Quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was used to measure mRNA levels for IL-6, IL-8, IL-1beta, IL-1alpha, TNFalpha, IFNgamma, IL-12, and HPRT.
- Enzyme-linked immunosorbent assay (ELISA) was employed to determine protein levels of the same cytokines.
- Spearman correlation analysis was performed to associate mRNA and protein levels.
Main Results:
- Strong correlations were observed between mRNA and protein levels for IL-6, IL-8, IL-1beta, IL-1alpha, TNFalpha, and IFNgamma.
- Significantly higher median levels of IL-6, IL-8, IL-1beta, and IFNgamma (mRNA and protein) were found in PVR patients compared to MH patients.
- While IL-6 mRNA was significantly higher in PVR vs. RD, protein levels of IL-6, IL-8, and IL-1beta were significantly elevated in PVR compared to RD patients.
Conclusions:
- Intravitreal infiltrating cells are the primary source of locally produced IL-6, IL-8, IL-1beta, and IFNgamma in PVR.
- A strong correlation between mRNA and protein levels supports the role of these cells in cytokine production.
- Cells invading the vitreous do not appear to be the local source of IL-12 mRNA, suggesting a peripheral origin for this cytokine.
