Limits...
Immune response after intermittent minimally invasive intraocular pressure elevations in an experimental animal model of glaucoma.

Gramlich OW, Teister J, Neumann M, Tao X, Beck S, von Pein HD, Pfeiffer N, Grus FH - J Neuroinflammation (2016)

Bottom Line: A wavelike IOP profile led to a significant neurodegeneration of optic nerve axons (-10.6 %, p < 0.001) and RGC (-19.5 %, p = 0.02) in iOHT eyes compared with fellow eyes.Belimumab-treated animals only showed slightly higher axonal survival and reduced serum IgG concentration (-29 %) after iOHT.Neuroinflammatory events, indicated by significantly upregulated microglia activation and IgG autoantibody depositions, were shown in all injured retinas.

View Article: PubMed Central - PubMed

Affiliation: Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg University Mainz, Langenbeckstr. 1, 55131, Mainz, Germany.

ABSTRACT

Background: Elevated intraocular pressure (IOP), as well as fluctuations in IOP, is a main risk factor for glaucoma, but its pathogenic effect has not yet been clarified. Beyond the multifactorial pathology of the disease, autoimmune mechanisms seem to be linked to retinal ganglion cell (RGC) death. This study aimed to identify if intermittent IOP elevations in vivo (i) elicit neurodegeneration, (ii) provokes an immune response and (iii) whether progression of RGC loss can be attenuated by the B lymphocyte inhibitor Belimumab.

Methods: Using an intermittent ocular hypertension model (iOHT), Long Evans rats (n = 21) underwent 27 unilateral simulations of a fluctuating pressure profile. Nine of these animals received Belimumab, and additional seven rats served as normotensive controls. Axonal density was analyzed in PPD-stained optic nerve cross-sections. Retinal cross-sections were immunostained against Brn3a, Iba1, and IgG autoantibody depositions. Serum IgG concentration and IgG reactivities were determined using ELISA and protein microarrays. Data was analyzed using ANOVA and Tukey HSD test (unequal N) or student's independent t test by groups.

Results: A wavelike IOP profile led to a significant neurodegeneration of optic nerve axons (-10.6 %, p < 0.001) and RGC (-19.5 %, p = 0.02) in iOHT eyes compared with fellow eyes. Belimumab-treated animals only showed slightly higher axonal survival and reduced serum IgG concentration (-29 %) after iOHT. Neuroinflammatory events, indicated by significantly upregulated microglia activation and IgG autoantibody depositions, were shown in all injured retinas. Significantly elevated serum autoantibody immunoreactivities against glutathione-S-transferase, spectrin, and transferrin were observed after iOHT and were negatively correlated to the axon density.

Conclusions: Intermittent IOP elevations are sufficient to provoke neurodegeneration in the optic nerve and the retina and elicit changes of IgG autoantibody reactivities. Although the inhibition of B lymphocyte activation failed to ameliorate axonal survival, the correlation between damage and changes in the autoantibody reactivity suggests that autoantibody profiling could be useful as a biomarker for glaucoma.

No MeSH data available.


Related in: MedlinePlus

Systemic immune response. Quantification of different antigen reactivities of control animals (CTRL), animals that received unilateral intermittent ocular hypertension (iOHT), and animals with unilateral intermittent ocular hypertension which received Belimumab treatment (iOHT + Belimumab). The left side (a–c )shows the immunoreactivities in relative intensities [U] per group against glutathione S-transferase (a), spectrin (b), and transferrin (c). Each triangle represents one animal, and the black line indicates the group median. Compared with the relative intensity of CTRL, iOHT was significantly upregulated (**, p < 0.01) for all investigated antigens. Compared with iOHT, all immunoreactivities of iOHT + Belimumab were significantly downregulated (##p < 0.01). All p values were calculated by Tukey’s HSD post hoc test (unequal N). Scatterplots of the number of optic nerve axons in a distinct area (no. of axons/0.05 mm2) against relative intensities of glutathione S-transferase (a), spectrin (b), and transferrin (c) are shown on the right side. For correlation analysis, p values lower than 0.05 were considered as significant. The correlation coefficient r ranged between −0.42 and −0.69 for the investigated antibody reactivities (shown in upper right corner of the diagrams). The gray fitting line shows the negative linear dependence between the number of axons per 0.05 mm2 and the relative intensities. CTRLs are represented as empty circles, iOHT as empty triangle, and iOHT + Belimumab as filled triangle. Significant values are indicated as follows: **p < 0.01 compared with control group, ##p < 0.01 compared with iOHT group
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4836145&req=5

Fig6: Systemic immune response. Quantification of different antigen reactivities of control animals (CTRL), animals that received unilateral intermittent ocular hypertension (iOHT), and animals with unilateral intermittent ocular hypertension which received Belimumab treatment (iOHT + Belimumab). The left side (a–c )shows the immunoreactivities in relative intensities [U] per group against glutathione S-transferase (a), spectrin (b), and transferrin (c). Each triangle represents one animal, and the black line indicates the group median. Compared with the relative intensity of CTRL, iOHT was significantly upregulated (**, p < 0.01) for all investigated antigens. Compared with iOHT, all immunoreactivities of iOHT + Belimumab were significantly downregulated (##p < 0.01). All p values were calculated by Tukey’s HSD post hoc test (unequal N). Scatterplots of the number of optic nerve axons in a distinct area (no. of axons/0.05 mm2) against relative intensities of glutathione S-transferase (a), spectrin (b), and transferrin (c) are shown on the right side. For correlation analysis, p values lower than 0.05 were considered as significant. The correlation coefficient r ranged between −0.42 and −0.69 for the investigated antibody reactivities (shown in upper right corner of the diagrams). The gray fitting line shows the negative linear dependence between the number of axons per 0.05 mm2 and the relative intensities. CTRLs are represented as empty circles, iOHT as empty triangle, and iOHT + Belimumab as filled triangle. Significant values are indicated as follows: **p < 0.01 compared with control group, ##p < 0.01 compared with iOHT group

Mentions: Antigen microarray analysis revealed significantly altered IgG autoantibody reactivities against the antigens glutathione S-transferase (CTRL: 18,280 ± 5752 U, iOHT: 49,091 ± 12,184 U, iOHT + Belimumab: 29,301 ± 11,925 U), spectrin (CTRL: 5391 ± 2519 U, iOHT: 9876 ± 2850 U, iOHT + Belimumab: 5429 ± 2323 U), and transferrin (CTRL: 18,055 ± 3682 U, iOHT: 33,020 ± 10,789 U, iOHT + Belimumab: 19,680 ± 4974 U). All of these changes were statistically significant when compared between iOHT and controls (glutathione S-transferase: p = 0.0002, spectrin: p = 0.006, transferrin: p = 0.003). Treatment of animals with the B lymphocyte inhibitor Belimumab led to significantly decreased immunoreactivity compared with iOHT animals (glutathione S-transferase: p = 0.001, spectrin: p = 0.002, transferrin: p = 0.003, Fig. 6a–c, left row). Importantly, statistically significant changes of the autoantibody reactivity between animals that received Belimumab and controls were not observed.Fig. 6


Immune response after intermittent minimally invasive intraocular pressure elevations in an experimental animal model of glaucoma.

Gramlich OW, Teister J, Neumann M, Tao X, Beck S, von Pein HD, Pfeiffer N, Grus FH - J Neuroinflammation (2016)

Systemic immune response. Quantification of different antigen reactivities of control animals (CTRL), animals that received unilateral intermittent ocular hypertension (iOHT), and animals with unilateral intermittent ocular hypertension which received Belimumab treatment (iOHT + Belimumab). The left side (a–c )shows the immunoreactivities in relative intensities [U] per group against glutathione S-transferase (a), spectrin (b), and transferrin (c). Each triangle represents one animal, and the black line indicates the group median. Compared with the relative intensity of CTRL, iOHT was significantly upregulated (**, p < 0.01) for all investigated antigens. Compared with iOHT, all immunoreactivities of iOHT + Belimumab were significantly downregulated (##p < 0.01). All p values were calculated by Tukey’s HSD post hoc test (unequal N). Scatterplots of the number of optic nerve axons in a distinct area (no. of axons/0.05 mm2) against relative intensities of glutathione S-transferase (a), spectrin (b), and transferrin (c) are shown on the right side. For correlation analysis, p values lower than 0.05 were considered as significant. The correlation coefficient r ranged between −0.42 and −0.69 for the investigated antibody reactivities (shown in upper right corner of the diagrams). The gray fitting line shows the negative linear dependence between the number of axons per 0.05 mm2 and the relative intensities. CTRLs are represented as empty circles, iOHT as empty triangle, and iOHT + Belimumab as filled triangle. Significant values are indicated as follows: **p < 0.01 compared with control group, ##p < 0.01 compared with iOHT group
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4836145&req=5

Fig6: Systemic immune response. Quantification of different antigen reactivities of control animals (CTRL), animals that received unilateral intermittent ocular hypertension (iOHT), and animals with unilateral intermittent ocular hypertension which received Belimumab treatment (iOHT + Belimumab). The left side (a–c )shows the immunoreactivities in relative intensities [U] per group against glutathione S-transferase (a), spectrin (b), and transferrin (c). Each triangle represents one animal, and the black line indicates the group median. Compared with the relative intensity of CTRL, iOHT was significantly upregulated (**, p < 0.01) for all investigated antigens. Compared with iOHT, all immunoreactivities of iOHT + Belimumab were significantly downregulated (##p < 0.01). All p values were calculated by Tukey’s HSD post hoc test (unequal N). Scatterplots of the number of optic nerve axons in a distinct area (no. of axons/0.05 mm2) against relative intensities of glutathione S-transferase (a), spectrin (b), and transferrin (c) are shown on the right side. For correlation analysis, p values lower than 0.05 were considered as significant. The correlation coefficient r ranged between −0.42 and −0.69 for the investigated antibody reactivities (shown in upper right corner of the diagrams). The gray fitting line shows the negative linear dependence between the number of axons per 0.05 mm2 and the relative intensities. CTRLs are represented as empty circles, iOHT as empty triangle, and iOHT + Belimumab as filled triangle. Significant values are indicated as follows: **p < 0.01 compared with control group, ##p < 0.01 compared with iOHT group
Mentions: Antigen microarray analysis revealed significantly altered IgG autoantibody reactivities against the antigens glutathione S-transferase (CTRL: 18,280 ± 5752 U, iOHT: 49,091 ± 12,184 U, iOHT + Belimumab: 29,301 ± 11,925 U), spectrin (CTRL: 5391 ± 2519 U, iOHT: 9876 ± 2850 U, iOHT + Belimumab: 5429 ± 2323 U), and transferrin (CTRL: 18,055 ± 3682 U, iOHT: 33,020 ± 10,789 U, iOHT + Belimumab: 19,680 ± 4974 U). All of these changes were statistically significant when compared between iOHT and controls (glutathione S-transferase: p = 0.0002, spectrin: p = 0.006, transferrin: p = 0.003). Treatment of animals with the B lymphocyte inhibitor Belimumab led to significantly decreased immunoreactivity compared with iOHT animals (glutathione S-transferase: p = 0.001, spectrin: p = 0.002, transferrin: p = 0.003, Fig. 6a–c, left row). Importantly, statistically significant changes of the autoantibody reactivity between animals that received Belimumab and controls were not observed.Fig. 6

Bottom Line: A wavelike IOP profile led to a significant neurodegeneration of optic nerve axons (-10.6 %, p < 0.001) and RGC (-19.5 %, p = 0.02) in iOHT eyes compared with fellow eyes.Belimumab-treated animals only showed slightly higher axonal survival and reduced serum IgG concentration (-29 %) after iOHT.Neuroinflammatory events, indicated by significantly upregulated microglia activation and IgG autoantibody depositions, were shown in all injured retinas.

View Article: PubMed Central - PubMed

Affiliation: Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg University Mainz, Langenbeckstr. 1, 55131, Mainz, Germany.

ABSTRACT

Background: Elevated intraocular pressure (IOP), as well as fluctuations in IOP, is a main risk factor for glaucoma, but its pathogenic effect has not yet been clarified. Beyond the multifactorial pathology of the disease, autoimmune mechanisms seem to be linked to retinal ganglion cell (RGC) death. This study aimed to identify if intermittent IOP elevations in vivo (i) elicit neurodegeneration, (ii) provokes an immune response and (iii) whether progression of RGC loss can be attenuated by the B lymphocyte inhibitor Belimumab.

Methods: Using an intermittent ocular hypertension model (iOHT), Long Evans rats (n = 21) underwent 27 unilateral simulations of a fluctuating pressure profile. Nine of these animals received Belimumab, and additional seven rats served as normotensive controls. Axonal density was analyzed in PPD-stained optic nerve cross-sections. Retinal cross-sections were immunostained against Brn3a, Iba1, and IgG autoantibody depositions. Serum IgG concentration and IgG reactivities were determined using ELISA and protein microarrays. Data was analyzed using ANOVA and Tukey HSD test (unequal N) or student's independent t test by groups.

Results: A wavelike IOP profile led to a significant neurodegeneration of optic nerve axons (-10.6 %, p < 0.001) and RGC (-19.5 %, p = 0.02) in iOHT eyes compared with fellow eyes. Belimumab-treated animals only showed slightly higher axonal survival and reduced serum IgG concentration (-29 %) after iOHT. Neuroinflammatory events, indicated by significantly upregulated microglia activation and IgG autoantibody depositions, were shown in all injured retinas. Significantly elevated serum autoantibody immunoreactivities against glutathione-S-transferase, spectrin, and transferrin were observed after iOHT and were negatively correlated to the axon density.

Conclusions: Intermittent IOP elevations are sufficient to provoke neurodegeneration in the optic nerve and the retina and elicit changes of IgG autoantibody reactivities. Although the inhibition of B lymphocyte activation failed to ameliorate axonal survival, the correlation between damage and changes in the autoantibody reactivity suggests that autoantibody profiling could be useful as a biomarker for glaucoma.

No MeSH data available.


Related in: MedlinePlus