Zinc Deficiency Does Not Correlate With Goblet Cell Depletion at Time of Fecal Transplant for Clostridium difficile Infection

Abstract

Introduction:Clostridium difficile infections (CDI) are characterized by a colon mucus barrier defect facilitating C. difficile adherence and toxin delivery. Zinc deficiency has been associated with recurrence of CDI after fecal microbiota transplant (FMT), but the underlying mechanism is unknown. In mice, zinc deficiency associates with jejunal goblet cell (GC) depletion that reverses with zinc repletion. We hypothesize that zinc deficiency predisposes patients to FMT failure by inhibiting the restoration of a healthy mucus barrier following recurrent CDI (rCDI). We aim to investigate whether zinc deficiency is associated with crypt or surface epithelium GC depletion at time of FMT for rCDI. Methods: We performed a retrospective cohort study of 45 patients (mean age, 65; 36 women) undergoing colon biopsies at time of FMT for rCDI from 9/2013 - 9/2016 at a tertiary care center who had serum zinc measured <30 days before FMT; 30 subjects had a normal level and 15 subjects had a low level (< 0.66 μg/mL). Hematoxylin-eosin-stained histologic slides from formalin-fixed biopsy specimens were reviewed with light microscopy. Primary outcomes were colon crypt epithelium GC density (cells/crypt) and colon surface epithelium GC density (cells/mm). Secondarily, the impact of zinc supplementation in patients with deficiency was analyzed. Results: Zinc deficiency was not associated with reduced crypt GC density: normal zinc subjects had 64+25 GC/crypt (mean+SD) while low zinc subjects had 75+32 GC/crypt (P=0.349, Mann-Whitney U [U]). Likewise, surface GC density did not vary by zinc status: normal zinc subjects had 49+23 GC/mm while low zinc subjects had 53+37 GC/mm (P=0.959, U). Among low zinc subjects, 8/15 received zinc supplements prior to biopsy. Receipt of zinc supplements was not associated with increased crypt GC density (77+41 GC/crypt Supplemented vs. 72+19 GC/crypt Not Supplemented, P=0.855, U) or increased surface GC density (41+19 GC/mm Supplemented vs. 68+48 GC/mm Not Supplemented, P=0.203, U). Conclusion: Zinc deficiency was not associated with depletion of colon crypt or surface epithelium GC. Among low zinc patients, receipt of zinc supplements was not associated with increased GC density. Low serum zinc may reflect both zinc depletion and underlying inflammatory response, and a relationship between zinc and colon mucus production cannot be excluded. Further studies are required to identify whether zinc deficiency contributes mechanistically to FMT failure.