Impact of dietary zinc on stimulated zinc secretion MRI in the healthy and malignant mouse prostate

Previous studies have shown that the zinc-responsive MRI probe, GdL1, can distinguish healthy versus malignant prostate tissues based upon differences in zinc content and secretion. In this study, mice were fed chow containing low, normal, or high zinc content for 3 weeks before imaging glucose stimulated zinc secretion (GSZS) by MRI. The distribution of zinc in prostate tissue in these three groups was imaged by synchrotron radiation X-ray fluorescence (SR-XRF). A zinc deficiency caused systemic and organ-level dysregulation, weight loss, and altered zinc bioavailability. Zinc efflux from the prostate increased in parallel to dietary zinc in healthy mice but not in TRAMP mice, consistent with a lowered capacity to store dietary zinc in malignant cells. This differential zinc efflux suggests that a dietary supplement of zinc prior to a GSZS study may enhance image contrast between healthy and malignant prostate tissue, thereby improving the accuracy of prostate cancer detection in man.