Changes in serum citrulline and arginine levels of SBS patients

Aim: Short Bowel Syndrome (SBS) patient with a residual small intestine length < 200 cm. The majority of serum citrulline (SC) is produced in the jejunal enterocytes. The cut off value of SC level in parenteral nutrition (PN) dependence was < 20 µmol/l, evaluated after bowel adaptation (BA). BA takes 1 – 3 years. The precursor of citrulline is glutamine (80 per cent), the remaining 20 per cent comprises arginine, proline and ornithine. The aim was to assess changes in SC and arginine levels of SBS patients at the start and end of expected BA period (BAP).

Method: We assessed the SC levels of 9 SBS patients in home parenteral nutrition (HPN) before and 1 – 3 years after residual small intestine adaptation. In the control group 6 patients were administered supplemental parenteral nutrition (SPN), of those three still had enterostomy and two suffered from serious renal insufficiency. Three control group patients received enteral nutrition (EN) only.

Results: There was no significant increase in average SC level before and after BAP. Arginine levels significantly decreased (p:0.048) in the EN group. Those without artificial nutrition and a stoma and/or with renal insufficiency had the lowest starting levels of citrulline and arginine compared to the other two groups (p:0.02). The control citrulline and arginine levels in the EN group, in the stoma and/or renal insufficiency group and in the PN group, citrulline and arginine levels decreased, were unchanged and increased, respectively.

Conclusions: There was no significant increase in the SC level of patients after residual BAP. This can be explained by the fact that after PN was stopped no precursors were administered (arginine: 9 g, proline: 8.7 g). In the case of enterostomy patients the higher level of amino-acid discharge counteracted the SC level increasing effect of the renal insufficiency. Starting citrulline and arginine levels were lowest in the SPN group with no stoma. SC and arginine levels increased in the SPN group, which we explained by the increase of the quantity of active enterocytes, by the venous route of citrulline precursors. Control values should be checked during PN, so that the increase in serum levels may give a timely warning to reduce or stop PN and enable the reduction of the frequency and severity of PN complications in the patient's home.