Recovery From Liver Dysfunction After Adult Isolated Intestinal Transplantation Without Liver Grafting

Pre-emptive Intestinal Transplant: The Surgeon's Point of View

Pre-emptive transplantation is a well-established practice for certain types of end-organ failure such as in the use of kidney transplantation. For irreversible intestinal failure, total parenteral nutrition (TPN) remains the gold standard, due to the suboptimal long-term results of intestinal transplantation. As such, the only role for pre-emptive transplantation, if at all, will be for patients identified to be at high risk of complications and mortality while on definitive long-term TPN. In these patients, the timing of early listing and transplantation could become life-saving, taking into account that mortality on the waiting list is still the highest for intestinal candidates. The development of simulation models or pre-transplant scoring systems could help in selecting patients based on potential outcome on TPN or with transplantation, and recent reports from high-volume centers identify few underlying pathologic conditions and some TPN complications as at higher risk of increased morbidity and mortality. A pre-emptive transplant could be used as a rehabilitative procedure in a well-selected case-by-case scenario, among TPN patients at risk of liver failure, repeated central line infections, mesenteric infarction, short bowel syndrome (SBS) <50 cm or with end stoma, congenital mucosal disease, desmoid tumors: These conditions must be carefully evaluated, not to underestimate the clinical stage nor to over-estimate the impact of a temporary situation. At the present time, diseases with a variable and unpredictable course, such as intestinal dysmotility disorders, or quality of life and financial issues are still far from being considered as indications for a pre-emptive transplant.

Pathogenesis and treatment of parenteral nutrition-associated liver disease

BACKGROUND

Parenteral nutrition-associated liver disease (PNALD) has been common in patients who require long-term parenteral nutrition. PNALD develops in 40%-60% of infants on long-term parenteral nutrition compared with 15%-40% of adults on home parenteral nutrition for intestinal failure. The pathogenesis of PNALD is multifactorial and remains unclear. There is no specific treatment. Management strategies for its prevention and treatment depend on an understanding of many risk factors. This review aims to provide an update on the pathogenesis and treatment of this disease.

DATA SOURCES

A literature search was performed on the MEDLINE and Web of Science databases for articles published up to October 2011, using the keywords: parenteral nutrition associated liver disease, intestinal failure associated liver disease, lipid emulsions and fish oil. The available data reported in the relevant literatures were analyzed.

RESULTS

The literature search provided a huge amount of evidence about the pathogenesis and management strategies on PNALD. Currently, lack of enteral feeding, extended duration of parenteral nutrition, recurrent sepsis, and nutrient deficiency or excess may play important roles in the pathogenesis of PNALD. Recent studies found that phytosterols, present as contaminants in soy-based lipid emulsions, are also an important factor in the pathogenesis. Moreover, the treatment of PNALD is discussed.

CONCLUSIONS

The use of lipid emulsions, phytosterols in particular, is associated with PNALD. Management strategies for the prevention and treatment of PNALD include consideration of early enteral feeding, the use of specialized lipid emulsions such as fish oil emulsions, and isolated small bowel or combined liver and small bowel transplantation. A greater understanding of the pathogenesis of PNALD has led to promising interventions to prevent and treat this condition. Future work should aim to better understand the mechanisms of PNALD and the long-term outcomes of its treatment.

Recent advances in the management of intestinal failure-associated liver disease

PURPOSE OF REVIEW

To summarize the current management of intestinal failure-associated liver disease (IFALD) by reviewing recent advances in our understanding of the condition and the effects of different therapeutic approaches.

RECENT FINDINGS

The importance of gastrointestinal length and continuity in the aetiology and treatment of IFALD has been demonstrated in both retrospective and interventional cohorts. A mechanism for the cholestatic effect of soy-based lipid has been described, and the clinical use of alternative lipid sources has demonstrated benefit. Prevention of IFALD has been shown with the use of erythromycin in neonates, and reversal of established IFALD has been demonstrated with isolated intestinal transplantation.

SUMMARY

A greater understanding of the mechanisms of IFALD has led to promising interventions to prevent and treat the condition. Other possible therapeutic targets require more formal evaluation, and further work is required to develop noninvasive tools for the assessment and prognosis of IFALD that will guide treatment and help in the selection of patients and timing of transplantation.

Managing liver dysfunction in parenteral nutrition

Parenteral nutrition is life saving in patients with intestinal failure but liver dysfunction is commonly encountered, especially in neonates. Although abnormal liver function tests associated with short-term parenteral nutrition are usually benign and transient, liver dysfunction in both children and adults receiving long-term parenteral nutrition can progress to end-stage liver disease and liver failure. The aetiology of parenteral nutrition-associated liver disease is complex and multifactorial, with a range of patient, disease and nutrition-related factors implicated. Sepsis is of particular importance, as is the lack of enteral nutrition and overfeeding with intravenous glucose and/or lipid. Deficiencies of a number of amino acids including choline and taurine have also been implicated. Management of hepatic dysfunction in parenteral nutrition should initially focus on preventing its occurrence. Sepsis should be managed appropriately, enteral nutrition should be encouraged and maximised where possible and parenteral overfeeding should be avoided. Provision of parenteral lipid should be optimised to prevent the adverse effects of both deficiency and excess, and cyclical rather than continuous parenteral feeding should be administered. There is some evidence of benefit in neonates from oral antibiotics to prevent intestinal bacterial overgrowth and from oral ursodeoxycholic acid, but less to support their use in adults. Similarly, data to support widespread use of parenteral choline or taurine supplementation are lacking at present. Ultimately, severe parenteral nutrition-associated liver disease may necessitate referral for small intestine and/or liver transplantation.