An Acute Retinal Model for Evaluating Blood Retinal Barrier Breach and Potential Drugs for Treatment

A low-cost, easy-to-use and powerful model system is established to evaluate potential treatments that could ameliorate blood retinal barrier breach. An ...

Rowan University School of Osteopathic Medicine

The fathead minnow is a useful species for evaluating the toxicity of wastewater effluents. While this fish is widely used for "survival" studies of metal toxicity, little or no work has been done on the tissue distribution of metals in fathead minnows. To determine the distribution of tissue lead, aquarium studies were conducted for several weeks with fish maintained in soft synthetic freshwater. Lead- (II) nitrate was added to three aquaria attaining concentrations of 20-30 ppb (aquarium B), 100-140 ppb (aquarium C), and roughly 200 ppb (aquarium D). Results were compared to controls (aquarium A). During the initial week, the majority of aquarium D fish died, whereas few deaths occurred in the other groups. Lead accumulation was dose- and tissue-dependent, with highest uptake by the gills. Gill concentrations of aquarium D fish averaged about 4-fold higherthan in skeleton or skin and muscle. In vitro, lead (2.5-25 ppm) caused dose-dependent reductions in the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) in gills incubated in physiological buffer. These findings demonstrate that fathead minnow gills bind and accumulate waterborne lead rapidly and preferentially and raise the possibility that gill lipid peroxidation contributes to lead toxicity at low water hardness.

Tissue lead concentration during chronic exposure of Pimephales promelas (fathead minnow) to lead nitrate in aquarium water.

The aim of the present study was to evaluate oxidative injury in gill pavement cells (GPCs) from fathead minnow (Pimephales promelas) using F2-isoprostane (F2-iP) release as an index of lipid peroxidation. Cells were isolated from pooled gill tissue by collagenase treatment, mechanical sieving, and Percoll density gradient centrifugation. Baseline levels of 8-epi-prostaglandin F2 alpha (8-epi-PGF2 alpha) were measured by incubating GPCs in physiological buffer (10(6) cells/ml) and enzyme immunoassay. After 60 min, the amount of immunoreactive 8-epi-PGF2 alpha (ir8-epi-PGF2 alpha) in control medium ranged from 1,374 to 5,515 pg/ml. Lead nitrate, 0.6 to 120 microM, did not influence ir8-epi-PGF2 alpha release, whereas FeCl3 stimulated release at 500 microM but not at 5 microM. Incubation medium was extracted for acidic lipids and analyzed by liquid chromatography/mass spectrometry/electrospray ionization. A compound in the medium exhibited a retention time on reverse-phase high-performance liquid chromatography nearly identical to that of synthetic 8-epi-PGF2 alpha The mass spectrum taken from the total ion chromatogram from 14.8 to 15.1 min contained a prominent ion at m/z 353, as expected for the molecular ion of 8-epi-PGF2 alpha. Similar results were obtained with tissue subjected to base hydrolysis. Mass spectra of extracted ion chromatograms obtained with gill extracts and authentic standard showed a close correspondence of fragment ions, providing definitive evidence for production and storage of F2-iPs by fish gills. In summary, F2-iP release occurs during lipid peroxidation injury to fish gill epithelium, and its measurement may facilitate aquatic toxicology studies of metallic and nonmetallic contaminants.

Release of the lipid peroxidation marker 8-epi-prostaglandin F2 alpha from isolated gill pavement cells.

The objectives of this study were to determine whether oxidative stress early in pregnancy influenced pregnancy outcome. A combination of assays were used for exogenous and endogenous anti-oxidants together with two well accepted biomarkers for oxidative stress, the urinary excretion of 8-iso-PGF(2alpha) (a biomarker marker for lipid oxidation, n=508) and 8-oxo-7,8 dihydro-2 deoxyguanosine (8-OHdG, a biomarker for DNA oxidation, n=487). The two biomarkers tracked different pregnancy outcomes. Isoprostanes were associated with an increased risk of pre-eclampsia and a decreased proportion of female births. In contrast, 8-OHdG tracked lower infant birthweight and shortened gestation duration. Birth defects were associated with low levels of 8-OHdG.

Oxidative stress early in pregnancy and pregnancy outcome.

Maresin conjugates in tissue regeneration (MCTR) are a new family of evolutionarily conserved chemical signals that orchestrate host responses to promote tissue regeneration and resolution of infections. Herein, we identified the novel MCTR3 and established rank order potencies and matched the stereochemistries of MCTR1, MCTR2 and MCTR3 using material prepared by total organic synthesis and mediators isolated from both mouse and human systems. MCTR3 was produced from endogenous substrate by E. coli activated human macrophages and identified in sepsis patients. Each of the three synthetic MCTR dose-dependently (1-100 nM) accelerated tissue regeneration in planaria by 0.6-0.9 days. When administered at the onset or peak of inflammation, each of the MCTR promoted resolution of E. coli infections in mice. They increased bacterial phagocytosis by exudate leukocytes (~15-50%), limited neutrophil infiltration (~20-50%), promoted efferocytosis (~30%) and reduced eicosanoids. MCTR1 and MCTR2 upregulated human neutrophil and macrophage phagocytic responses where MCTR3 also proved to possess potent actions. These results establish the complete stereochemistry and rank order potencies for MCTR1, MCTR2 and MCTR3 that provide novel resolution moduli in regulating host responses to clear infections and promote tissue regeneration.

Bernd W. Spur

Department of Cell Biology

Rowan University School of Osteopathic Medicine

An Acute Retinal Model for Evaluating Blood Retinal Barrier Breach and Potential Drugs for Treatment

Bernd W. Spur

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Cell Biology

Rowan University School of Osteopathic Medicine

An Acute Retinal Model for Evaluating Blood Retinal Barrier Breach and Potential Drugs for Treatment

Department of Cell Biology