This study was carried out in the Department of Hepatobiliary Surgery of the Affiliated Drum Tower Hospital, Medical School of Nanjing University, China according to the principles and guidelines of the Helsinki Declaration of 1975 revised in 2000. The protocol was approved by the Ethics Committee of the Affiliated Drum Tower Hospital. All patients fully understood the objective and adverse reactions of the study, and signed the written informed consent voluntarily prior to study enrollment.

From January 2006 to July 2010, we prospectively investigated 66 patients (45 men and 21 women; mean age, 51.6 years; range, 34-64 years) who underwent orthotopic liver transplantation in the Department of Hepatobiliary Surgery at the Affiliated Drum Tower Hospital of Medical School of Nanjing University. Recipients with manifest metabolic diseases (e.g., diabetes mellitus and hyperthyroidism) or severe renal abnormality were excluded. No acute rejection, primary transplanted liver dysfunction or second operation, which may affect the evaluation of liver function, were seen during the first 9 d after transplantation. The selection criteria for donors in this study included: (1) age < 50 years, matched ABO blood group and no history of chronic liver disease; (2) no evidence of malignant tumor, viral hepatitis or other viral infections; (3) no cirrhosis, mass or severe fatty degeneration of the donor liver seen during organ harvesting; and (4) liver biopsies of each donor liver taken before transplantation were reviewed by two pathologists. Donor livers with normal pathology or mild fatty change (10%-30%) were included in this study (Figure 1).

Open in New Tab   Full Size Figure   Download Figure

Figure 1 Pathology of liver biopsy of donor liver taken before transplantation. Mild steatosis was observed in donor liver. (Hematoxylin and eosin staining; paraffin-embedded 5 μm thick sections; ×200).

After transplantation, these patients were randomized into two groups based on the randomization chart generated by the Statistical Analysis System (SAS): (1) PN group (33 patients), without supplementation of omega-3 fatty acids in addition to routine treatment; and (2) PUFA group (33 patients), with PN supplemented with omega-3 fatty acids in addition to routine treatment.

This is a randomized controlled clinical study carried out in the Department of Hepatobiliary Surgery of our hospital. Nutrition Risk Screening 2002 (NRS 2002) scoring system was used, and the post-operative NRS 2002 score was ≥ 3 in all the patients, which meant that all the patients need nutritional support.

The PN was given around the clock for seven days from the second day after operation. The two nutritional support groups were isonitrogenous and isocaloric. Nitrogen intake was 0.16 g/kg body weight per day, caloric intake was 104.5 kJ/kg per day, and lipid intake was 1.0 g/kg per day. The nonprotein calories were provided with dextrose (4.0 g/kg per day) and fat emulsion in a ratio of 2:1. The only source of lipids in PN group was the standard lipid emulsion (20% emulsion, with a ratio of long-chain triglycerides to medium-chain triglycerides of 1:1, Huarui Pharmaceuticals, Jiangsu, China), and in PUFA group omega-3 fish oil lipid emulsion (Omegaven, 10%, 2 mL/kg per day, Fresenius Kabi Co., Austria) replaced part of the standard lipid emulsion. Both groups received 1.0 g amino acid/kg per day, and they were administered a commercially available branched-chain amino acid solution (Branched-chain amino acid solution 20%, Huarui Pharmaceuticals, Jiangsu, China). The ratio of nonprotein calories to nitrogen in both nutritional support groups was 653 kJ:1 g. The omega-3 fish oil lipid emulsion-containing solutions were prepared by the clinical pharmacist under aseptic condition and adjusted according to the weight of each individual patient. The amino acids, fat emulsion and dextrose mixture with electrolytes, vitamins, and trace elements were administered through a central venous catheter. As soon as the bowel function returned on days 3 or 4 after transplantation, all patients in the two groups were given liquid carbohydrate and cow’s milk protein.

The surgical treatment was standardized, and modified piggyback orthotopic liver transplantation was performed by three groups of surgeons using the same approach. After operation, all the patients in the two groups were treated with the same antibiotics and antivirutics, and 20 g of albumin was administered intravenously daily for five days to prevent any complications caused by hypoalbuminemia.

Venous heparin blood samples were obtained on days 1 (the day before transplantation), 2 and 9 after surgery and liver function assessment was made. Serum total bilirubin (TB), direct bilirubin (DB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and prothrombin time (PT) were measured by an automatic biochemical analyzer (HITACHI 7600, Japan).

Liver biopsy with fine needle was conducted after reperfusion of donor liver and on day 9 after surgery, respectively. Hepatic specimens for light microscopy were fixed with formalin and embedded in paraffin. Sections were stained with hematoxylin and eosin for histological examination. Portal inflammation in the liver biopsy specimens was semiquantified by calculating inflammatory cells in portal tracts based on the Knodell histology activity index (HAI)[15]. Portal inflammation was scored as 0, no portal inflammation; 1, mild (sprinkling of inflammatory cells in < 1/3 of portal tracts); 3, moderate (increased inflammatory cells in 1/3-2/3 of portal tracts); and 4, marked (dense packing of inflammatory cells in > 2/3 of portal tracts).

The assessment of clinical outcome was based on post-transplant investigations as shown by: (1) post-transplant mechanical ventilation; (2) total hospital stay; (3) infectious morbidities (pneumonia, intra-abdominal abscess, central line sepsis, wound infection, and urinary tract infection); (4) acute and chronic rejection; (5) mortality (intensive care unit mortality, hospital mortality, 28-d mortality, and survival at one year post-transplant surveillance period).

These post-transplant parameters were investigated and documented daily during the patients’ post-transplant hospital stay and the period of one-year postoperative follow-up.

The results were expressed as mean ± SD. Data were analyzed using the SAS. Differences between means were evaluated using Student t test when normal distribution was confirmed by Shapiro-Wilks test. When the hypothesis of normal distribution was rejected, differences between groups were tested by nonparametric statistics using Mann-Whitney test for unpaired samples and Wilcoxon criteria for paired samples. Fisher’s exact test was used for analysis of categorical values when appropriate. A P value of < 0.05 was considered significant.

No significant difference of pre-operative liver function was observed between the two groups. On days 2 and 9 after operation, a significant decrease of ALT (299.16 U/L ± 189.17 U/L vs 246.16 U/L ± 175.21 U/L, P = 0.024) and PT (5.64 s ± 2.06 s vs 2.54 s ± 1.15 s, P = 0.035) was seen in PUFA group compared with PN group. And there was no significant decrease of the following parameters tested on days 2 and 9: AST (116.31 U/L ± 42.19 U/L vs 121.09 U/L ± 53.14 U/L, P=0.682), TB (93.93 μmol/L ± 45.49 μmol/L vs 87.20 μmol/L ± 61.12 μmol/L, P = 1.439), DB (42.74 μmol/L ± 17.36 μmol/L vs 36.22 μmol/L ± 21.63 μmol/L, P = 0.815) and LDH (156.12 U/L ± 89.20 U/L vs 119.10 U/L ± 69.72 U/L, P = 1.112) in PUFA group compared with PN group (Table 2).

The histological examination after reperfusion revealed some swelling hepatocytes and inflammatory cell infiltration in the portal areas, and no significant difference of numerical score of portal inflammation was observed between the two groups.

Histological examination on day 9 in PN group revealed more inflammatory cells aggregating in hepatic sinusoid lumen, extensive swelling and some balloon-like degeneration of hepatocytes, extensive congestion, and bilirubin deposit in the hepatic plasma (Figure 2A). These were ameliorated markedly by parenteral nutritional support with omega-3 fatty acids (Figure 2B), and the numerical score of portal inflammation was significantly lowered in PUFA group (Table 3). There was no sign of acute rejection in both groups.

Open in New Tab   Full Size Figure   Download Figure

Figure 2 Histological appearance of the transplanted liver on day 9 after surgery. A: Extensive swelling, balloon-like degeneration and necrosis of hepatocytes, extensive congestion and bilirubin deposit were observed in the hepatic plasma in parenteral nutrition group; B: The results of histological examination were ameliorated markedly in the polyunsaturated fatty acid group. (Hematoxylin and eosin staining; paraffin-embedded 5 μm thick sections; ×200).

There was no significant difference of post-transplant mechanical ventilation between the two groups (P > 0.05). Compared with PN group, the post-transplant hospital stay was significantly shortened in PUFA group (P < 0.05). Infectious complications occurred in 6 cases of PN group (2 cases of pneumonia, 3 cases of intra-abdominal abscess and 1 case of urinary tract infection), and in 3 cases of PUFA group (2 cases of pneumonia, 1 case of intra-abdominal abscess). No acute or chronic rejection and hospital mortality were found in the two groups. All patients were followed up, and the one-year mortality in PN group was 9.1% (3/33), one died of pulmonary infection, one died of severe intra-hepatic cholangitis and hepatic dysfunction and the other of hepatic cell carcinoma recurrence. Only one patient in PUFA group (1/33, 3.1%) died of biliary complication and hepatic dysfunction during follow-up (Table 4).

The liver recipients with liver insufficiency are known to experience a higher incidence of severe protein/calorie malnutrition, and malnutrition is associated with a greater risk of postoperative complications and mortality in patients undergoing liver transplantation. And ischemia/reperfusion injury associated with liver transplantation often leads to hepatic dysfunction despite the improvements in surgical techniques and perioperative medication.

Omega-3 fatty acids exert anti-inflammatory and immunomodulatory properties through their ability to modulate the synthesis of different eicosanoids. Recent studies have described that supplementation with omega-3 fatty acids decreases the rate of inflammatory complication, the length of hospital stay, and the mortality after major abdominal surgeries.

Although most transplant centers use the similar post-transplant nutritional support as for other major abdominal operations, few studies have elucidated the role of postoperative nutritional support in the organ recipient. Based on the results of this study, the authors have shown that post-transplant nutritional support in the form of a solution enriched with branched-chain amino acids, dextrose, medium-chain triglycerides and omega-3 fatty acids might offer a benefit in terms of preserved liver function and better clinical outcome, including the decreased infectious morbidities and post-transplant hospital stay.

This study has shown that omega-3 fatty acids-supplemented parenteral nutrition (PN) significantly improves the injury of transplanted liver, decreases the infectious morbidities, and shortens the post-transplant hospital stay. The nutritional support strategy is recommended in patients undergoing liver transplantation.

The manuscript evaluates the potential for supplementation with polyunsaturated fatty acid to ameliorate hepatic injury associated with reperfusion and PN. It provides evidences about an efficient nutritional support strategy for liver transplanted patients.