Anti-Inflammatory Effects of Clarstatin, a Shared-Epitope-Antagonistic Cyclic Peptide, on Experimental Autoimmune Uveitis in Mice.
Clarstatin showed a significant reduction in inflammation in mouse models of uveitis, but its relevance to human treatment remains to be established.
Where it sits
this study against the rest of the cibinetide corpusSummary and findings
The study evaluated the effects of Clarstatin, a cyclic peptide, on experimental autoimmune uveitis (EAU) in mice. Clarstatin was administered intraperitoneally, and its impact was compared to corticosteroids. The results indicated a significant reduction in clinical and histological scores associated with EAU.
Abstract
<h4>Purpose</h4>Polymorphism and mutations of human leukocyte antigens (HLAs) and calreticulin are risk factors for uveitis. Here, we sought to determine the therapeutic effects of Clarstatin, a cyclic peptide antagonist of the HLA shared-epitope-calreticulin interaction, in experimental autoimmune uveitis (EAU) models.<h4>Methods</h4>Mice were injected with Clarstatin intraperitoneally and its effect was compared to that of corticosteroid. EAU was evaluated clinically and histologically. Ocular infiltration of CD45+ hematopoietic cells and splenocyte CD4+ expression were determined using immunofluorescence and flow cytometry (fluorescence-activated cell sorting [FACS]). ELISA was used to measure the ocular level of the proinflammatory cytokines.<h4>Results</h4>Clarstatin significantly ameliorated the severity of EAU in the C57BL/6J mild and the B10.RIII severe mice models. There was a significant dose and time-dependent decrease, in the range of 30% to 80%, in the clinical score (P < 0.05), histological score (P < 0.05), and number of retinal and spleen CD45+ cells (P < 0.05 and P < 0.001, respectively), a comparable effect to corticosteroid. Clarstatin reduced the intraocular levels of interleukin 6 (IL-6; P < 0.05) and monocyte chemoattractant protein-1 (MCP-1; P < 0.01) by 41% and 59%, respectively.<h4>Conclusions</h4>Systemic delivery of Clarstatin significantly improved mild and severe EAU. Its potential anti-inflammatory therapeutic effects represent a novel mode of treatment in ocular inflammation. It may also be a relevant treatment modality in systemic autoimmune conditions in which calreticulin plays a role in their pathogenesis.
Background
The study investigates the role of Clarstatin, a cyclic peptide antagonist of the HLA shared-epitope-calreticulin interaction, in treating experimental autoimmune uveitis (EAU). Previous research has identified polymorphisms in human leukocyte antigens as risk factors for uveitis. This study is significant as it explores a novel therapeutic approach for ocular inflammation, which could have implications for broader autoimmune conditions.
Methods
Mice were injected intraperitoneally with Clarstatin, and its effects were compared to corticosteroids. The study evaluated EAU through clinical and histological assessments, measuring ocular infiltration of CD45+ cells and splenocyte CD4+ expression using immunofluorescence and flow cytometry. Proinflammatory cytokines were quantified via ELISA.
Results
Clarstatin significantly reduced the severity of EAU, with a clinical score decrease ranging from 30% to 80% (P < 0.05). Histological scores also decreased significantly (P < 0.05), alongside reductions in retinal CD45+ cells (P < 0.05) and spleen CD45+ cells (P < 0.001). Intraocular levels of IL-6 and MCP-1 were reduced by 41% (P < 0.05) and 59% (P < 0.01), respectively.
Interpretation
These findings suggest that Clarstatin may have significant anti-inflammatory effects in EAU models, comparable to corticosteroids. However, the effect sizes, while statistically significant, may not be clinically meaningful without further human studies. The study's reliance on mouse models and potential confounding factors limit the generalizability of the results.
Key findings
- 30% to 80% decrease in clinical score, P < 0.05.
- 30% to 80% decrease in histological score, P < 0.05.
- Significant reduction in retinal CD45+ cells, P < 0.05.
- Significant reduction in spleen CD45+ cells, P < 0.001.
- 41% reduction in IL-6 levels, P < 0.05.
- 59% reduction in MCP-1 levels, P < 0.01.
Limitations
- Limited to mouse models, not human data.
- Potential confounding factors in treatment evaluation.
- Short follow-up duration not reported.