Lipid Composition of the Human Eye: Are Red Blood Cells a Good Mirror of Retinal and Optic Nerve Fatty Acids?

International audienceBACKGROUND: The assessment of blood lipids is very frequent in clinical research as it is assumed to reflect the lipid composition of peripheral tissues. Even well accepted such relationships have never been clearly established. This is particularly true in ophthalmology where the use of blood lipids has become very common following recent data linking lipid intake to ocular health and disease. In the present study, we wanted to determine in humans whether a lipidomic approach based on red blood cells could reveal associations between circulating and tissue lipid profiles. To check if the analytical sensitivity may be of importance in such analyses, we have used a double approach for lipidomics. METHODOLOGY AND PRINCIPAL FINDINGS: Red blood cells, retinas and optic nerves were collected from 9 human donors. The lipidomic analyses on tissues consisted in gas chromatography and liquid chromatography coupled to an electrospray ionization source-mass spectrometer (LC-ESI-MS). Gas chromatography did not reveal any relevant association between circulating and ocular fatty acids except for arachidonic acid whose circulating amounts were positively associated with its levels in the retina and in the optic nerve. In contrast, several significant associations emerged from LC-ESI-MS analyses. Particularly, lipid entities in red blood cells were positively or negatively associated with representative pools of retinal docosahexaenoic acid (DHA), retinal very-long chain polyunsaturated fatty acids (VLC-PUFA) or optic nerve plasmalogens. CONCLUSIONS AND SIGNIFICANCE: LC-ESI-MS is more appropriate than gas chromatography for lipidomics on red blood cells, and further extrapolation to ocular lipids. The several individual lipid species we have identified are good candidates to represent circulating biomarkers of ocular lipids. However, further investigation is needed before considering them as indexes of disease risk and before using them in clinical studies on optic nerve neuropathies or retinal diseases displaying photoreceptors degeneration

Rare B-Cell Non-Hodgkin’s Lymphomas in Childhood and Adolescence

Non-Hodgkin’s lymphoma (NHL) results from malignant proliferation of lymphocytes and is generally restricted to lymphoid tissue such as lymph nodes, Peyer’s patches, and spleen. However, pediatric NHL can rarely and solely arise in other anatomical sites, such as the kidney, skin, lung, eye, bone, stomach, or cavities as an effusion. Adult-type lymphomas (chronic lymphocytic leukemia and multiple myeloma) have scarcely been reported in children. Understanding of these rare pediatric B-NHLs is mainly based on small pediatric case series or adult studies. Due to the limited number of cases the exact prevalence of the abovementioned NHL types cannot be easily estimated. Moreover, the index of suspicion is usually low because of the rarity, resulting sometimes in late diagnosis with a significant impact on prognosis. Since these NHL types are often more well-studied in adult population, adult-based therapeutic approaches are also applied in children. Prognosis in pediatric patients may be different from that of adults. So, more international collaborative efforts are needed in order to identify specific prognostic factors, including molecular and cytogenetic variables and define specific pediatric treatment protocols.</p