Elevated Fundus Autofluorescence in Monkeys Deficient in Lutein, Zeaxanthin, and Omega-3 Fatty Acids

PURPOSE. We quantified fundus autofluorescence (FAF) in the nonhuman primate retina as a function of age and diets lacking lutein and zeaxanthin (L/Z) and omega-3 fatty acids. METHODS. Quantitative FAF was measured in a cross-sectional study of rhesus macaques fed a standard diet across the lifespan, and in aged rhesus macaques fed lifelong diets lacking L/Z and providing either adequate or deficient levels of omega-3 fatty acids. Macular FAF images were segmented into multiple regions of interest, and mean gray values for each region were calculated using ImageJ. The resulting FAF values were compared across ages within the standard diet animals, and among diet groups and regions. RESULTS. Fundus autofluorescence increased with age in the standard diet animals, and was highest in the perifovea. Monkeys fed L/Z-free diets with either adequate or deficient omega-3 fatty acids had significantly higher FAF overall than age-matched standard diet monkeys. Examined by region, those with adequate omega-3 fatty acids had higher FAF in the fovea and superior regions, while monkeys fed the diet lacking L/Z and omega-3 fatty acids had higher FAF in all regions. CONCLUSIONS. Diets devoid of L/Z resulted in increased retinal autofluorescence, with the highest values in animals also lacking omega-3 fatty acids. The increase was equivalent to a 12-to 20-year acceleration in lipofuscin accumulation compared to animals fed a standard diet. Together these data add support for the role of these nutrients as important factors in lipofuscin accumulation, retinal aging, and progression of macular disease

A multi-tissue, multi-species assessment of lipid and urea stable isotope biases in mesopredator elasmobranchs

The application of stable isotope analysis (SIA) is increasing in elasmobranch trophic ecology, but inconsistency remains in terms of the tissue pre-treatment methods chosen to remove biases introduced by lipids and urea. SIA of a range of non-lethally extracted tissues from a diverse group of elasmobranchs, including mesopredators, is increasing, yet most studies assume that isotope biases from lipid and urea are the same across tissues and species. To determine tissue- and species-specific isotope biases across treatment methods, three tissues and their components [muscle, fin, and blood separated into plasma and red blood cells (RBC)] were non-lethally extracted from three species of mesopredatory elasmobranchs and subjected to one of three treatment methods: (1) deionized water rinse [DW], (2) chloroform/methanol lipid extraction [LE], or (3) deionized water followed by chloroform/methanol [DW+LE]. In muscle δ13C, all treatments displayed minimal variation (∼ 0‰) but large increases in δ15N (∼ 1‰) indicated urea removal. Fin δ13C values decreased with DW but increased with LE and DW+LE, whilst all treatments increased fin δ15N (∼ 0.5‰), suggesting removal of both lipid and urea. Plasma δ13C and δ15N displayed high individual variation; large decreases in δ13C (∼−0.8‰) across all treatments, but particularly DW, suggested the removal of 13C-enriched compounds while a small increase in δ15N (∼ 0.2‰) suggested minimal urea removal. In RBC, all treatments showed small δ13C declines (∼−0.5‰), with no difference in δ15N, suggesting minimal removal of 13C-enriched compounds and urea. For muscle and fin, DW+LE is the most appropriate treatment to standardize δ13C and δ15N consistently across individuals and tissues. The large individual variation in treatment effects on plasma suggests it is unsuitable for current treatment methods. Consistent treatment effects for RBC allow for DW+LE standardization, however, broader species-specific effects are unknown. The importance of treatment choice for accurately estimating prey contributions to elasmobranch diet was highlighted using Bayesian stable isotope mixing model comparisons, with prey contributions varying significantly among treatments. This variability suggests that ecological inferences from elasmobranch tissue SIA are not robust to different treatment methods. It is recommended that studies employ standardized corrections using a combined DW+LE treatment where applicable

Optomotor and immunohistochemical changes in the juvenile S334ter rat

The aim of this study was to examine the temporal relationship between behaviorally measured visual thresholds, photoreceptor degeneration and dysfunction, synaptic and neuronal morphology changes in the retina in the S334ter line 4 rat. Specifically, we examined the optokinetic tracking (OKT) behavior in S334ter rats daily and found that OKT thresholds reflected normal values at eye opening but quickly reduced to a non-response level by postnatal day (P) 22. By contrast, the scotopic electroretinogram (ERG) showed a much slower degeneration, with substantial scotopic function remaining after P90 as previously demonstrated for this line of rats. Photopic b-wave amplitudes revealed functional levels between 70 and 100% of normal between P30 and P90. Histological evidence demonstrated that photoreceptor degeneration occurred over many months, with an outer nuclear layer (ONL) roughly half the thickness of a normal age-matched control at P90. Immunohistochemical analysis revealed a number of changes in retinal morphology in the Tg S334ter line 4 rat that occur at or before P40 including: elevated levels of rod opsin expression in the ONL, cone photoreceptor morphology changes, glial cell activation, inner retinal neuron sprouting, and microglial cell activation. Many of these changes were evident at P30 and in some cases as early as eye opening (P15). Thus, the morphological changes occurred in concert with or before the very rapid loss of the behavioral (OKT) responses, and significantly before the loss of photoreceptors and photoreceptor function

Phagocytosis of Photoreceptor Outer Segments by Transplanted Human Neural Stem Cells as a Neuroprotective Mechanism in Retinal Degeneration

Purpose. Transplantation of human central nervous system stem cells (HuCNS-SC) into the subretinal space of Royal College of Surgeons (RCS) rats preserves photoreceptors and visual function. To explore possible mechanism(s) of action underlying this neuroprotective effect, we performed a detailed morphologic and ultrastructure analysis of HuCNS-SC transplanted retinas. Methods. The HuCNS-SC were transplanted into the subretinal space of RCS rats. Histologic examination of the transplanted retinas was performed by light and electron microscopy. Areas of the retina adjacent to HuCNS-SC graft (treated regions) were analyzed and compared to control sections obtained from the same retina, but distant from the transplant site (untreated regions). Results. The HuCNS-SC were detected as a layer of STEM 121 immunopositive cells in the subretinal space. In treated regions, preserved photoreceptor nuclei, as well as inner and outer segments were identified readily. In contrast, classic signs of degeneration were observed in the untreated regions. Interestingly, detailed ultrastructure analysis revealed a striking preservation of the photoreceptor–bipolar–horizontal cell synaptic contacts in the outer plexiform layer (OPL) of treated areas, in stark contrast with untreated areas. Finally, the presence of phagosomes and vesicles exhibiting the lamellar structure of outer segments also was detected within the cytosol of HuCNS-SC, indicating that these cells have phagocytic capacity in vivo. Conclusions. This study reveals the novel finding that preservation of specialized synaptic contacts between photoreceptors and second order neurons, as well as phagocytosis of photoreceptor outer segments, are potential mechanism(s) of HuCNS-SC transplantation, mediating functional rescue in retinal degeneration.Supported by grants from the Spanish Ministry of Economy and Competitiveness (BFU2012-36845), Instituto de Salud Carlos III (RETICS RD12/0034/0010), Organización Nacional de Ciegos Españoles (ONCE), and StemCells, Inc. (NC)

Pleomorphic adenoma of the parotid gland in children

Objective: To evaluate the presentation, imaging characteristics and treatment outcome of pleomorphic adenoma of the parotid in the pediatric population