Metronidazole Attenuates the Intensity of Inflammation in Experimental Autoimmune Uveitis.

Autoimmune uveitis is a serious sightthreatening disease that in many cases fails to respond to conventional immunosuppressive or biological therapy. Experimental models used in research allow more detailed study of pathogenesis of the autoimmune process and testing new therapeutic strategies. Recent results show that infection can trigger autoimmune diseases, and some commensal microorganisms are essential in causing disease activity. The aim of this work was to assess the effect of broadspectrum antibiotics - combination of metronidazole and ciprofloxacin or metronidazole alone - on the intensity of intraocular inflammation in experimental autoimmune uveitis (EAU). EAU was induced in mouse strain C57BL/6J by interphotoreceptor retinoid- binding protein in complete Freund's adjuvant and pertussis toxin. The grade of uveitis was assessed clinically and histologically in haematoxylin and eosin- stained tissues. Lymphocytes and macrophages were detected in cryosections using the immunoperoxidase method with antibodies. The therapy was commenced one week before EAU induction and continued throughout the experiment. In addition, metronidazole treatment was also started two weeks before EAU induction. Antibiotics significantly reduced the intensity of uveitis compared to the control group (P < 0.05). The effects of combination of ciprofloxacin and metronidazole and of metronidazole alone were similar when the therapy started one week before EAU induction (P < 0.05). Metronidazole commenced two weeks before EAU induction and throughout the experiment suppressed the intensity of EAU with even higher statistical significance (P < 0.0001). It can be assumed that the high protective effect of metronidazole on EAU intensity may be due not only to its antimicrobial effect, but also to its immunomodulatory activity.

[The Clinical Signs of Experimental Autoimmune Uveitis]. / Klinické projevy experimentální autoimunitní uveitidy.

INTRODUCTION: Autoimmune uveitis is a sight threatening disease which in many cases fails to respond to conventional immunosuppressive or biological therapy. The research in experimental models of autoimmune uveitis helps to find new therapeutical strategies. The aim of this study is to present the clinical and histological signs of experimental autoimmune uveitis (EAU) in mice. METHODS: EAU was induced in C57BL/6 mice by subcutaneous application of IRBP (interphotoreceptor retinoid binding protein) in complete Freunds adjuvant and intraperitoneal application of pertussis toxin. Clinical evaluation of uveitis was performed in vivo using special imaging system with otoscope. Histological evaluation of uveitis was performed at day 35 post induction of EAU on hematoxylin and eosin stained frozen sections. Clinical and histological grading was used to assess the inflammation intensity of EAU. RESULTS: The intensity of inflammation is depicted on representative fundus images and histological images of retina at day 35 post induction. CONCLUSION: The model of EAU is robust and reproducible and allows us to study the immunopathological mechanisms of inflammation and its regulation. The inflammatory signs in our model are similar to findings of posterior uveitis of autoimmune etiology in humans, thus we may apply our experimental results in human medicine.

[Tear Osmolarity in Patients with Severe Dry Eye Syndrome Before and After Autologous Serum Treatment: a Comparison with Tear Osmolarity in Healthy Volunteers]. / Osmolarita slz u pacientu s tezkým syndromem suchého oka pred a po aplikaci autologního séra. Porovnání s hodnotami zdravých dobrovolníku.

INTRODUCTION: Dry eye syndrome (DES) is a multifactorial disease of the tears and ocular surface. Recently, treatment with autologous serum eye drops (AS-ed) has been frequently used in these patients. Significant improvement correlates well with clinical, laboratory and subjective findings. It is assumed that one of the key factors in the development of the disease is increased tear osmolarity. The aims of our study were to test tear osmolarity measurements in clinical practice, to examine if osmolarity values differ before and after a 3-month application of 20% AS-ed, and to determine if the values differ between patients with severe DES and healthy individuals. METHODS: The study included 35 patients with severe DES (Schirmer test<5 mm/5 min) and 23 healthy volunteers. Tear osmolarity values (TearLab Osmolarity System), the Schirmer test (ST1), vital ocular surface staining and subjective feelings (the OSDI questionnaire) were assessed in patients with DES before and after treatment with 20% AS-ed. Further, the tear osmolarity values were compared between healthy subjects and patients with DES before and after treatment with AS-ed. RESULTS: The values of OSDI and vital staining significantly decreased in patients with DES after the treatment (p<0.0001). ST1 and tear osmolarity did not change significantly after the treatment. ST1 values in healthy individuals were significantly higher (p<0.0001) and the OSDI values significantly lower (p<0.0001) than the results obtained in patients before and after treatment. Tear osmolarity was not statistically different between healthy subjects (306 mosmol/l) and patients with DES (302 and 301 mosmol/l before and after treatment respectively). CONCLUSION: We demonstrated a positive effect of AS treatment on the ocular surface in patients with DES. However, the osmolarity values did not differ before and after treatment with AS, and they also did not differ significantly between DES patients and healthy individuals. In accordance with other recent studies, our results raise questions concerning the value of the TearLab Osmolarity System for evaluating therapeutic effect and also as a tool for DES diagnosis.