Abstract 13: Novel Humanized Recombinant T Cell Receptor Ligand Protects Brain in Females after Experimental Stroke
Background: Recent evidence emphasizes the importance of T lymphocytes of differing subtypes in ischemic cell death mechanisms. RTL, composed of partial major histocompatibility complex (MHC) ClassIImolecules covalently bound to myelin peptides, is currently under clinical study for multiple sclerosis. We have shown that RTL is effective in male mice treated with middle cerebral artery occlusion (MCAO) by inhibiting early accumulation of inflammatory cells. We now show for the first time that post-treatment improves functional outcomes and that efficacy is present in females.
Methods: HLA-DR2 transgenic female mice (17-20g) were subjected to 60 min MCAO (isoflurane). Cortical laser-Doppler flowmetry (LDF) was continuously monitored and only animals with LDF of below 40% of baseline during MCAO were included in study. Mice were treated with RTL1000 RTL 1000 (HLA-DR2 moiety linked to human MOG-35-55 peptide) (0.1mL, 1mg/mL sq) (RTL) or vehicle (VEH) at 3h, 24h, 48h, 72h after reperfusion. Mice were recovered for 96h or 2 weeks post-injury for measurement of histology (TTC staining) or behavioral testing respectively. Sham operated females received either vehicle or RTL and identical testing paradigms.
Results: All sham mice showed no evidence of infarction or behavioral deficit. Mortality rate and general health score were similar between MCAO groups. RTL mice sustained smaller infarcts as compared to VEH group (% of contralateral structure): Total hemisphere: 13.9 ±4.1 % RTL (n=15) vs. 28.3 ±3.0% (p < 0.05) in VEH (n=15); cortex: 19.9 ±6.3 % in RTL vs. 44.2 ±5.0% (p < 0.05) in VEH; striatum 24.2 ±6.8% in RTL vs. 52.4 ± 4.7% (p < 0.05) in VEH. Histological protection was profound; 6 out of 15 in MCAO-RTL group showed no measurable infarction at 96 hours. Using a standard cylinder test repeated at 3, 7 and 14 days post MCAO, we observed that RTL strongly improved functional recovery as compared to MCAO-VEH group (RTL vs. VEH: day 3, p=0.02, day 7 p=0.00 and day 14 p=0.00). By 7days, animal performance in the RTL group was not different from shams. In contrast, recovery in the VEH group remained poor at all time points.
Conclusion: RTL1000 offers strong protection after ischemic injury in females, including prolonged improvement of functional outcomes.
Author Disclosures: J. Pan: None. J. Palmateer: None. T. Schallert: None. H. Offner: Research Grant; Significant; R01 NS076013, R01 NS075887, R42 NS065515. P. Hurn: None.
- © 2014 by American Heart Association, Inc.