Dawn M. Matteson

Effect of sex hormones on experimental autoimmune uveoretinitis (EAU).

Purpose: Sex hormones have been associated with the prevalence, susceptibility, and severity of autoimmune disease. Although the exact mechanism is unknown, sex hormones are reported to influence cytokine production, specifically by affecting the balance of Th1 and Th2 effector cells. We evaluated the effect of estrogen, progesterone, and testosterone in autoimmune uveoretinitis (EAU), a rodent model of human ocular autoimmune disease. Methods: Lewis rats implanted with either β‐estradiol (estrogen), 5‐dihydrotestosterone (5‐DHT), norgestrel (progesterone), or estrogen plus progesterone were immunized with the retinal antigen interphotoreceptor retinoid binding protein (IRBP) peptide. Evaluation of EAU was based on histology of the eyes and measurement of peripheral immunological responses of DTH and lymphocyte proliferation to S‐antigen. Quantitative RT‐PCR was used to measure IFN‐γ and IL‐10 mRNA in the eyes. Results: In female rats 5‐DHT significantly decreased, estrogen slightly enhanced, but progesterone or estrogen + progesterone did not affect EAU. In contrast, in male rats 5‐DHT slightly decreased, estrogen moderately decreased, progesterone did not effect, but, estrogen + progesterone slightly decreased EAU. The results correlated with the ocular levels of Th1 (IFN‐γ) and Th2 (IL‐10) cytokine messengers. Conclusion: The data support the hypothesis that sex hormones may affect autoimmune diseases by inducing changes in the cytokine balance. This suggests that sex hormone therapy could be considered as an adjunct to anti‐inflammatory agents to treat ocular autoimmune diseases in humans.

Cytokines and apoptotic molecules in experimental melanin-protein induced uveitis (EMIU) and experimental autoimmune uveoretinitis (EAU)

The cytokine profile and occurrence of apoptosis during experimental melanin-protein induced uveitis (EMIU) were investigated and compared with that of experimental autoimmune uveoretinitis (EAU). EMIU or EAU was induced in Lewis rats. Eyes were collected at different time points after immunization. Cytokine mRNA expression was identified in the inflammatory cells in the uvea of EMIU rats; IL-2, IFN-gamma and IL-12 increased at the peak of the inflammation, and then tapered off as inflammation subsided. IL-4 and IL-10 increased at the peak of ocular inflammation, and persisted with inflammation resolved. Fas and FasL were expressed consistently in ocular resident cells of EMIU, but were elevated in EAU. In EAU, Bcl-2 expression showed a sharp peak in inflammatory cells but not in the resident cells. In EMIU, high levels of Bcl-2 were present and persisted in both ocular resident and inflammatory cells. Expression of Bax was relatively stable in both EAU and EMIU. Cellular DNA fragmentation was detected in the retinal glial cells of EAU and some inflammatory cells of EMIU. In EMIU, the dynamics of Th1 cytokines were consistent with the ocular inflammation, whereas persistent expression of Th2 cytokines was consistent with their known regulatory role. The continuous high expression of Bcl-2 and the high ratio of Bcl-2 to Bax in the eyes of EMIU may possibly contribute to prevention of ocular tissue damage, and of inflammatory cells from undergoing apoptosis, thus resulting in chronic recurrent inflammation.

Apoptosis in cytomegalovirus retinitis associated with AIDS.

PURPOSE To determine the role of apoptosis in the pathogenesis of cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome. METHODS Forty-three eyes from patients with cytomegalovirus retinitis treated before the introduction of highly active anti-retroviral therapy were examined by routine histopathology and in situ techniques to detect apoptosis (TUNEL assay). Apoptosis was graded on a scale from 0 to 3+ by quantitating the number of TUNEL positive cells per case using a standard grading procedure. Statistical analysis describing the association between apoptosis grade and the proportions of eyes with active CMV infection, with choroidal inflammation and treated with the sustained-release intravitreal ganciclovir implant was performed using the Armitage procedure. RESULTS Apoptosis in both CMV infected and uninfected retinal cells was detected in 28 of 41 eyes (68%); 13 (45%) with active and 15 (55%) with inactive cytomegalovirus retinitis. The degree of apoptosis was mild (1+) in 14 eyes, moderate (2+) in 6 eyes and severe (3+) in 8 eyes. Apoptosis was not identified in two eyes without CMVR. An increase in apoptosis grade was positively associated with active CMVR (p = 0.014). There was no significant association between apoptosis and choroidal inflammation. The presence and the severity of apoptosis was less in eyes treated with the sustained-release intravitreal ganciclovir implant compared to those treated with systemic anti-viral therapy, however, the difference was not statistically significant. CONCLUSIONS Apoptosis contributes to retinal cell loss in eyes with cytomegalovirus retinitis associated with AIDS but did not correlate with the progressive loss of retinal cell function in patients with treated, inactive CMVR.

Morphologic and genetic analysis of retinal angioma associated with massive gliosis in a patient with von Hippel-Lindau disease

Abstract We report morphologic and genetic analysis of bilateral retinal angiomas in a 35-year-old patient with von Hippel-Lindau (VHL) disease. Enucleation of both eyes revealed extensive intraocular tumor. Whereas the right eye demonstrated large amounts of retinal angioma tissue, the left eye showed small areas of retinal angioma associated with massive diffuse retinal gliosis. Genetic analysis of the angioma showed allelic deletion of the VHL gene locus, suggesting that the origin of the angiomas was directly related to the patient’s underlying VHL disease. Genetic analysis of the pleomorphic glial proliferation showed no allelic VHL gene deletion, which is consistent with the assessment that the glial component represents a reactive process. Apoptosis detected by TUNEL revealed lack of DNA fragmentation in the angioma; in contrast, many positive signals were found in the massive gliosis. We confirmed that the abnormal VHL genes were located in the “stromal” cells of the retinal angioma. Massive gliosis in VHL disease is a true reactive retinal gliosis.