The pathogenesis of growth failure in paediatric liver disease

Insulin-like growth factor and epidermal growth factor treatment: new approaches to protecting steatotic livers against ischemia-reperfusion injury

Hepatic steatosis is a major risk factor in ischemia-reperfusion (I/R). IGF-binding proteins (IGFBPs) modulate IGF-I action by transporting circulating IGF-I to its sites of action. Epidermal growth factor (EGF) stimulates IGF-I synthesis in vitro. We examined the effect of IGF-I and EGF treatment, separately or in combination, on the vulnerability of steatotic livers to I/R. Our results indicated that I/R impaired IGF-I synthesis only in steatotic livers. Only when a high dose of IGF-I (400 microg/kg) was given to obese animals did they show high circulating IGF-I:IGFBP levels, increased hepatic IGF-I levels, and protection against damage. In lean animals, a dose of 100 microg/kg IGF-I protected nonsteatotic livers. Our results indicated that the combined administration of IGF-I and EGF resulted in hepatic injury parameters in both liver types similar to that obtained by IGF-I and EGF separately. IGF-I increased egf expression in both liver types. The beneficial role of EGF on hepatic I/R injury may be attributable to p38 inhibition in nonsteatotic livers and to PPAR gamma overexpression in steatotic livers. In conclusion, IGF-I and EGF may constitute new pharmacological strategies to reduce the inherent susceptibility of steatotic livers to I/R injury.

Treatment options for chronic cholestasis in infancy and childhood

Altered bile flow physiology leads to many complications commonly seen in patients with cholestatic liver disease, regardless of the etiology. For each individual patient, a coordinated and effective treatment strategy must address the presence and the severity spectrum of malabsorption, malnutrition, vitamin and micronutrient deficiencies, pruritus, xanthomata, ascites, and liver failure, which are attributed directly or indirectly to diminished bile flow. An aggressive approach to maximizing the nutritional status of the child is vital to ensure optimal growth and development. Protein-calorie and/or fat supplementation is best discussed early. Decreasing the percentage of dietary long-chain triglycerides, providing medium-chain triglycerides, and ensuring adequate essential fatty acid and adequate protein intake may be helpful. Fat-soluble vitamin (A, D, E, and K) levels and micronutrient levels must be carefully and serially monitored and supplemented as necessary. Because the mechanisms that mediate pruritus of cholestasis remain to be determined, the use of empirical therapies continues to be standard practice. Ursodeoxycholic acid may ameliorate pruritus. Antihistamines and rifampicin may also provide temporary relief for some children. Based on the evidence that increased central opioidergic tone is present in chronic cholestasis, the use of opiate antagonists is promising but has not been evaluated in children. Selected patients with refractory pruritus that have failed maximal medical therapy have benefited from partial external biliary diversion. Ongoing dialogue with the family regarding the indications for liver transplantation is reasonable. Optimization and adherence with the pretransplant medical management enhance the chances for a successful outcome from liver transplantation. Specific to the pediatric patient, optimizing growth, development and nutrition, minimizing discomfort and disability, and aiding the child and family in coping with the stress, social, and emotional effects of chronic liver disease remain paramount.

Cystatin C, an easy and reliable marker for assessment of renal dysfunction in children with liver disease and after liver transplantation

Renal dysfunction of variable severity is being increasingly recognized as a major complication of calcineurin inhibitors (CI), in some patients even necessitating renal transplantation. Close and effective monitoring of the renal function is indicated. Current methods for this monitoring are calculation of the glomerular filtration rate (GFR) based on creatinine or exogenous substances like 51Cr-EDTA. The first method is unreliable in children and the second is expensive and cumbersome. Cystatin C has been shown to be an accurate marker of glomerular filtration but has not been evaluated in a large cohort of pediatric patients before and after liver transplantation (LT). We evaluated the accuracy of cystatin C in 62 children (30 male) with LT, who had their 51Cr-EDTA measured on 40 occasions prior to LT and on 47 occasions after LT. The reciprocal of cystatin C correlated better with 51Cr-EDTA GFR (r = .78) than the reciprocal of creatinine (r = .40). Diagnostic accuracy in the identification of reduced GFR was assessed by ROC analysis. Cystatin C yielded the highest area under the ROC curve (AUC) in all groups assessed. From these data a cutoff level of cystatin C predicting 51Cr-EDTA GFR < 80 ml/min/1.73 m2 was calculated. A level of 1.06 mg/L was found to have a sensitivity of 91% and a specificity of 81%. Applying this cutoff level in our patient group would have avoided 51Cr-EDTA GFR estimation in 43 of the 87 estimations. In conclusion, the use of this simple test could be recommended as screening of renal dysfunction in children with liver disease and after LT.

End-stage Liver Disease in Children

The treatment of children with end-stage liver disease involves the coordinated management of nutritional deficiencies, ascites, pruritus, encephalopathy, and portal hypertension. The implementation of management strategies depends upon a parent or guardian to administer the plan in the context of a child at different stages of developmental, physiologic, emotional, and physical maturity. Fat-soluble vitamins (A, D, E, and K) and micronutrient levels should be monitored routinely and supplemented if deficient. In some patients, supplemental nutrition to provide additional energy and protein is needed to ensure optimal growth and development. Ascites often respond to spironolactone and sodium restriction, but may require the addition of a loop diuretic or even abdominal paracentesis. Pruritus significantly impairs the quality of life of patients and is typically treated with ursodeoxycholic acid, rifampin, or an antihistamine. Partial biliary diversion, or liver transplant in some instances, is necessary for patients with self-mutilating pruritus that results from intrahepatic cholestasis. Hepatic encephalopathy is poorly defined in infants and small children. Elevated serum ammonia serves as a surrogate marker for encephalopathy, which is treated with dietary protein restriction and lactulose. The usefulness of medical prophylaxis for esophageal varices has been noted in adults, though such studies have not been performed in children. If variceal bleeding becomes problematic, treatment with endoscopic variceal banding or sclerotherapy is indicated. A surgical shunt to reduce portal pressure is needed in some cases. Orthotopic liver transplant ultimately may be necessary to overcome the unrelenting consequences of end-stage liver disease.

Percutaneous endoscopic gastrostomy for continuous feeding in children with chronic cholestasis

BACKGROUND

Malnutrition associated with chronic cholestasis in children often requires continuous enteral feeding through a nasogastric tube, which may be poorly tolerated.

METHOD

Percutaneous endoscopic gastrostomy was performed in five children (age range, 20 months to 13 years) with severe cholestasis (Alagille syndrome in four; biliary atresia in one) and severe malnutrition (mean weight, -2.6 standard deviations; mean height, -2.7 standard deviations) who were awaiting liver transplantation. The pull-through technique was used in patients under general anesthesia, and the button was set within 2 months.

RESULTS

Minor wound infection required antibiotic therapy in one patient. In the four children with Alagille syndrome, enteral feeding by means of percutaneous endoscopic gastrostomy was used until liver transplantation for a mean period of 14 months with a mean weight gain of 350 g/mo and a mean height gain of 0.53 cm/mo. Seventeen months to 3 years, 3 months after liver transplantation, all four children were alive and in good clinical condition with normal readings in liver function tests. The technique had to be discontinued in the child with biliary atresia because of secondary occurrence of ascites, gastric intolerance, and refractory wound infection.

CONCLUSION

Percutaneous endoscopic gastrostomy may be a valuable alternative to nasogastric tube for nutritional support in children with cholestasis and mild portal hypertension.