Mohammad Shawaqfeh¹, Jennifer Bonner¹, Shimin Zhang¹, Laura Matarese², Kareem Abu-Elmagd², Raman Venkataramanan^1,2

¹University of Pittsburgh/UPMC, Pittsburgh, PA, United States; ²Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, United States

Small bowel transplantation is increasingly being performed to treat patients with intestinal failure. A recent study of serum micronutrient concentrations in intestinal transplant patients revealed that Vitamin B6  deficiency occurred in 96% of recipients within a median onset of 30 d (range: 4–118 d) after transplantation (Matarese et al Am J Clin Nutr 2009;89:1–6). In this study the Vitamin B6 status was assessed by measuring the serum level of the active metabolite pyridoxal 5’ phosphate (P5P). We hypothesized that increased degradation of P5P in SBT patients secondary to the drugs used or to the status of the graft may be responsible for the low levels of P5P.

Methods: Urine samples from 16 small bowel transplant recipients and 16 healthy control subjects who were part of a pharmacokinetic study were used in the analysis. In the transplant recipients, urine samples were collected during a study session in the early post-transplant period (10-40 days post-transplant) as well as during a study session four months to one year after transplant.  Urinary 4-Pyridoxic acid (4-PA, an inactive metabolite of P5P) was measured by a validated HPLC method.

Results: Tweleve hoururinary4-PA amounts were significantly higher in transplant group (22.8 μg) compared to the control group (2.5 μg) (p<0.05). All transplant patients who did not receive any vitamin supplementation had a significantly higher levels of  urinary 4-PA( P<0.05) than controls. The early session transplant group showed higher (42.51μg) , excretion than the later group (12.97μg) , however excretion in both transplant groups was significantly higher than the control group (P<.05).

Conclusion: The higher urinary 4-PA amounts seen in the transplant groups may indicate increased degradation or higher excretion of P5P in the transplant group than in healthy controls. The underlying reasons for this difference are being explored further.