Microsphere antioxidant and sustained erythropoietin-R76E release functions cooperate to reduce traumatic optic neuropathy.

Wild-type erythropoietin (EPO) is promising for neuroprotection, but its therapeutic use is limited because it causes a systemic rise in hematocrit. We have developed an EPO-R76E derivative that maintains neuroprotective function without effects on hematocrit, but this protein has a short half-life in vivo. Here, we compare the efficacy and carrier-induced inflammatory response of two polymeric microparticle (MP) EPO-R76E sustained release formulations based on conventional hydrolytically degradable poly(lactic-co-glycolic acid) (PLGA) and reactive oxygen species (ROS)-degradable poly(propylene sulfide) (PPS). Both MP types effectively loaded EPO-R76E and achieved sustained release, providing detectable levels of EPO-R76E at the injection site in the eye in vivo for at least 28 days. Testing in an in vitro oxidative stress assay and a mouse model of blast-induced indirect traumatic optic neuropathy (bITON) showed that PPS and PLGA MP-mediated delivery of EPO-R76E provided therapeutic protection. While unloaded PLGA MPs inherently increase levels of pro-inflammatory cytokines in the bITON model, drug-free PPS MPs have innate antioxidant properties that provide therapeutic benefit both in vitro and in vivo. Both PLGA and PPS MPs enabled sustained release of EPO-R76E, providing therapeutic benefits including reduction in inflammation and axon degeneration, and preservation of visual function as measured by electroretinogram. The PPS-based MP platform is especially promising for further development, as the delivery system provides inherent antioxidant benefits that can be harnessed to work in complement with EPO-R76E or other drugs for neuroprotection in the setting of traumatic eye injury.

In vivo photothermal optical coherence tomography of gold nanorod contrast agents.

Photothermal optical coherence tomography (PT-OCT) is a potentially powerful tool for molecular imaging. Here, we characterize PT-OCT imaging of gold nanorod (GNR) contrast agents in phantoms, and we apply these techniques for in vivo GNR imaging. The PT-OCT signal was compared to the bio-heat equation in phantoms, and in vivo PT-OCT images were acquired from subcutaneous 400 pM GNR Matrigel injections into mice. Experiments revealed that PT-OCT signals varied as predicted by the bio-heat equation, with significant PT-OCT signal increases at 7.5 pM GNR compared to a scattering control (p < 0.01) while imaging in common path configuration. In vivo PT-OCT images demonstrated an appreciable increase in signal in the presence of GNRs compared to controls. Additionally, in vivo PT-OCT GNR signals were spatially distinct from blood vessels imaged with Doppler OCT. We anticipate that the demonstrated in vivo PT-OCT sensitivity to GNR contrast agents is sufficient to image molecular expression in vivo. Therefore, this work demonstrates the translation of PT-OCT to in vivo imaging and represents the next step towards its use as an in vivo molecular imaging tool.

Potentiating effect of HLA matching and blood transfusion on renal allograft survival.

An analysis of HLA (A and B) recipient-donor matching on the outcome of 105 cadaver kidney transplants performed at the Medical College of Virginia transplant center revealed that there is a significant, overall difference (P = 0.03) between recipients receiving kidneys mismatched at two or less HLA loci versus recipients mismatched at three or more loci, the fewer mismatch category showing a better graft survival. The effect of blood transfusion prior to transplantation was studied and found to improve the outlook, especially in the best matched groups. The number of transfusions does show a significant effect (P = 0.04) in the subgroup of patients with two or less mismatches, but for patients with three or more mismatches, the number of transfusions does not seem to matter (P = 0.83). However, in this study even the allografts mismatched at three or more loci had a 1-year graft survival of greater than 65%, indicating that factors other than HLA or blood transfusion play significant roles in the graft outcome. Although the findings are based on a somewhat small number of patients, the statistical significance suggests a potentiating effect of HLA matching and blood transfusion on renal allograft survival.

Relationship of B cell alloantibodies to renal allograft survival.

To define the relationship of donor-specific B lymphocyte alloantibodies to renal allograft survival, longitudinal serum samples obtained pre- and post-transplantation were examined for antibodies cytotoxic to donor B lymphocytes. Ten of 17 renal allograft recipients had antibodies to donor B lymphocytes but not T lymphocytes either pre- and/or post-transplantation. Three patients underwent successful transplants despite preformed B cell antibodies; however, seven who developed B cell antibodies only after transplantation are either undergoing chronic rejection (4) or have had severe rejection crisis (3). Seven patients with no B cell antibodies have functioning grafts. In all cases, B cell antibodies were detected before biochemical and clinical evidence of rejection. Similar findings were noted when sera of 38 renal transplant recipients were examined for B cell antibodies cytotoxic to an unrelated panel of B lymphocytes. These results demonstrate that the development of B cell alloantibodies after transplantation is often associated with rejection and that successful renal transplantation can be performed across a positive B cell crossmatch.