Jennifer L. Guerin

Jennifer L. Guerin

University of New Hampshire

Nutrition Sciences


1995

Mentor: Dennis J. Bobilya, Ph.D. - Assistant Professor of Nutritional Biochemistry

Characterizing the Method of Zinc Transport Across an In Vitro Model of the Blood-Brain Barrier

Zinc is an essential trace mineral whose presence in the body is necessary for the function of over 200 enzymes, normal DNA synthesis, and the modulation of synaptic transmission in the brain. These studies investigated zinc transport from the blood into the brain across the cells of the brain capillary wall which comprise the blood-brain barrier (BBB).

The goal was to isolate and grow brain capillary cells and to determine the effects of analogous metals on zinc transport across an in vitro model of the BBB. Capillaries were isolated from the brains of miniature swine. The procedure included mechanical and enzymatic digestion of the brain tissue followed by separation of the capillary cells from contaminating cell types based on their size and density. Enzyme concentrations and incubation times were manipulated to increase cell yields.

Our in vitro model consisted of capillary cells grown on porous membranes suspended between two chambers containing whole minipig serum and artificial cerebrospinal fluid to represent the capillary lumen and brain, respectively. The serum had 10 mM zinc and was labeled with 65Zn tracer to measure zinc transport. To determine the specificity of the transport mechanism for zinc, analogous metals (cadmium, copper, manganese, lead, aluminum) were added to the serum at 20 mM concentrations. Characterizing the method of zinc transport across the BBB will enable us to understand disruptions in this mechanism which result in the abnormal zinc concentrations characteristic of neuropathologies such as Alzheimer's Disease.

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