Prospective randomized, placebo-controlled study: role of branched-chain amino acids infusion as adjunct therapy post-liver surgery for patients in the intensive care unit

Abstract

Background and aim

Several animal studies have shown that Branched-chain amino acids (BCAAs) may prevent acute liver injury, although its effects in humans are as yet undetermined. Thus the purpose of this study is to evaluate the impact of intravenous BCAAs infusion on liver profile post-liver surgery in the intensive care unit (ICU).

Methods

A randomized study that was applied for post liver surgery patients who were randomly allocated to receive either intravenous BCAA immediately post-operative or placebo.

Measurements

Follow-up liver profile, Child–Pugh, and SOFA scores during the first week post-surgery.

Main results

A significant decline of bilirubin and ALT on day three and five in the BCAA group compared to the control group respectively. There was a significant improvement of PT on day seven 12.5 in the BCAA group versus 12.9 in the control group, p-value 0.01. Total bilirubin levels decreased by 75% in the BCAA group, whereas in the control group saw an increase of 6.25% from the baseline which was statistically significant, p-value 0.0376. SOFA score was markedly improved in the BCAA group (p-value 0.013). In addition to a significantly shorter ICU stay in the BCAA group than in the control group (p-value 0.018).

Conclusion

There are beneficial effects of BCAAs infusion post-liver surgery; including improved metabolic profile (liver function tests), and shorter ICU stay.

Trial registration

(Clinicaltrials.gov registration number:NCT03448848), 28/02/2018.

Introduction

The branched-chain amino acids (BCAAs) are made up of three essential amino acids; valine, leucine, and isoleucine. The body is unable to synthesize essential amino acids of other amino acids, so they must be supplied to the body through food or supplements [1].

The three BCAAs represent about 40% of the daily requirement of all nine essential amino acids indicating their importance. They make up about 35% of all muscle tissue. All BCAAs or leucine alone can stimulate protein synthesis [2] and as well can inhibit protein degradation depending on the context [3].

BCAAs supplementation has been shown a stimulatory effect on liver regeneration. The proposed mechanism for liver regeneration is, BCAAs; particularly leucine stimulates stellate cells in the liver to secrete hepatocyte growth factor [4].

BCAAs activate rapamycin signaling pathways in the liver that enhance both albumin synthesis in the liver, protein and glycogen synthesis in muscles. Therefore, treatment with BCAAs has been reflected on the chemical profile including recovery of serum albumin and declining of serum bilirubin levels [5].

Oral BCAA treatment has also been reported to improve protein malnutrition especially during the early stages of liver cirrhosis, increasing serum albumin level. BCAA supplementation was reported to improve the quality of life in cirrhotic patients; improved weakness, fatigue, and sleep disturbance [6].

BCAAs (particularly leucine) stimulate insulin release from the pancreatic β-cells thus allowing for better glucose utilization & reversing the catabolic, hyperglucagonemic state of cirrhosis [6].

Recent studies in animal models have shown that BCAAs can induce transcription of the glucose transporter-2(GLUT2) and liver-type glucokinase (L-GK) that facilitate glucose uptake by the liverthus improving glucose utilization [7]. Therefore, BCAAs supplementation inhibits protein breakdown and stimulates protein synthesis [3].

One molecular-level study showed improvement of phagocytic function of neutrophils and possibly natural killer T cell (NKT) activity with BCAAs supplementation, however, it has not been statistically significant [8].

Several animal studies have shown that BCAAs may prevent acute liver injury, although its effects in humans are as yet undetermined. BCAA supplementation after hepatectomy promotes rapid improvement in protein metabolism and inhibits progression to liver cirrhosis [9].

Till the time of our research, there are very limited studies that have discussed the role of BCAA post liver surgery.

Thus the purpose of this study is to evaluate the impact of intravenous BCAAs infusion on liver profile post-liver surgery in the intensive care unit (ICU).

Patients & methods

This was a double-blinded (participants and researcher) randomized controlled, parallel-group study in ICU-NHTMRI. Patients were randomized into 2 groups using a computer-generated random number list and participants were blinded for group allocation.

Eligibility criteria

The eligibility criteria applied in this study were as follows: adults aged between 18 and 75 years who are admitted to the ICU of National Hepatology & Tropical Medicine Research Institute (NHTMRI) post elective liver surgery e.g. hepatocellular carcinoma, liver hemangioma, hydatid cyst resection, donor for living donated liver transplant.

The exclusion criteria were as follows: pregnant patients, hemodynamic instability requiring vasopressor, and severe malnutrition; body mass index (BMI < 16).

Study design

Patients who were admitted to ICU for postoperative care following liver surgery; received the routine postoperative including hemodynamic monitoring, prophylactic antimicrobial for 24h, pain control, and enteral feeding initiation as soon as possible. Patients were randomly allocated to receive immediately postoperative (Day 0) coded bottles either with intravenous (IV) BCAAs in a dose of 0.5-1gm/Kg/day; 0.5gm/Kg/day for intolerant patients (those who developed postoperative hepatic encephalopathy) or 1gm/Kg/day for tolerant patients for 48 h and might be increased for 5 days if the patient stayed in ICU for any medical or surgical cause.

All demographic data will be obtained including the patients’ age, body mass index, associated co-morbidities (diabetes mellitus & hypertension),Child–Pugh score, Sequential Organ Failure Assessment (SOFA), the type of liver surgery, & the nutritional status according to nutritional risk screening 2002 (NRS 2002) [10]; well-nourished if NRS 2002 < 3 while malnourished if NRS 2002 ≥ 3 prior BCAAs infusion.

Vital signs including the heart rate, mean arterial pressure (MAP), central venous pressure (CVP), arterial oxygen saturation (SaO₂), and insulin requirements, urine volume & fluid balance will be recorded on admission (day 0), then will be followed up and recorded for seven days postoperative at regular intervals during treatment.

Laboratory investigations including the complete blood profile, prothrombin time (PT), liver enzymes; Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), serum bilirubin, and serum albumin will be recorded at randomization as a baseline (the baseline was immediately withdrawn postoperative once admitted to ICU prior to the start of BCAA or placebo and this is called day 0) & will be assessed on day 3, 5, and 7 of the study.

Outcome measures of the study

The main outcome is to evaluate the impact of BCAAs on overall liver functions (AST, ALT, serum bilirubin & PT), Child–Pugh & SOFA scores during the first week post-surgery.

Secondary outcomes are to assess the infectious morbidity, the length of antibiotic treatment and non-infectious morbidity; occurrence of hepatic encephalopathy, ruptured esophageal varices, wound dehiscence, nutritional status change, length of ICU stay, length of hospital stay & 28day mortality.

Sample size estimation

This study aims to compare the mean improvement in liver enzymes in both groups. Based on the previous study by Tangkijvanichet al. [11] indicating that SGPT was decreased after treatment with BCAA compared to before treatment (57.5 ± 34.5vs. 36.2 ± 23.9). In the control group, the mean SGPT 50.0 ± 35.8 before treatment compared to 47.6 ± 31.4 after treatment to detect a true difference in means between groups with a power 80% and a level of significance of 5% (two-sided)a total sample size of 52 patients will be needed, i.e. 26 patients in each group.Sample size calculated using g power.

Statistical analysis

The Statistical Package of Social Science (SPSS) (version 26) was used to generate results. The normality of the data was tested using the Kolmogorov–Smirnov single-sample test. Numerical data were summarized as means and standard deviations (SD) or medians and ranges as appropriate. Medians were used mainly for skewness and not normally distributed data. While qualitative data were described as frequencies and percentages. Comparison between two groups for numerical variables was done using the Mann–Whitney –U test (nonparametric t-test) as appropriate. The relation between qualitative data was done using the Chi-square test. Probability (p-value) equal to or less than 0.05 is considered significant.

An intention-to-treat analysis was employed to account for patient dropouts. Missing data due to dropouts were handled using a multiple imputation technique combined with the last observation carried forward (LOCF) approach to ensure that all patients were included in the analysis, thereby preserving the validity of the results.

Results

As shown in Fig. 1, n = 60 of the randomized subjects recruited in the study and were included in the final analysis. The baseline characteristics were similar in patients receiving BCAA infusion or placebo_. However, regarding the type of liver surgery, the benign causes present 36.7% in the BCAA group (four of them were hemangiomas and adenoma, another three had hydatid cysts, and four were donors for liver transplants) and 63.3% in the placebo group (four of them were hemangiomas and adenoma, seven had hydatid cysts, and eight were donors) (Table 1).

Fig. 1.

CONSORT flow diagram showing the flow of patients throughout the study

Table 1.

Demographic, operative, and clinical scores variables

	Total	BCAA	Placebo (Non BCAA)
Characteristic	(n = 60)	(n = 30)	(n = 30)	p-value
Age (years)
Mean ± SD	45.0 ± 15.9	49.1 ± 14.1	41.5 ± 16.7
				0.078
Sex (n = %)
Female	27.0 (45.0)	10.0 (33.3)	17.0 (56.7)
Male	33.0 (55.0)	20.0 (66.7)	13.0 (43.3)	0.069
Diabetes (n = %)
No	49.0 (81.7)	22.0 (73.3)	27.0 (90.0)
Yes	11.0 (18.3)	8.0 (26.7)	3.0 (10.0)	0.095
Hypertension (n = %)
No	48.0 (80.0)	24.0 (80.0)	24.0 (80.0)
Yes	12.0 (20.0)	6.0 (20.0)	6.0 (20.0)	1.000
Weight
Mean ± SD	77.3 ± 14.8	79.1 ± 13.1	75.5 ± 16.6
				0.230
BMI
Mean ± SD	27.9 ± 5.8	28.2 ± 5.7	27.7 ± 5.9
				0.695
Cause of liver surgery (n = %)
Benign cause	30.0 (50.0)	11.0 (36.7)	19.0 (63.3)
Malignant	30.0 (50.0)	19.0 (63.3)	11.0 (36.7)	0.039
Segments removed (n = %)
`Two segments	18.0 (30.0)	10.0 (33.3)	8.0 (26.7)	0.248
One segment	31.0 (51.7)	17.0 (56.7)	14.0 (46.7)
Donor for LDLT	11.0 (18.3)	3.0 (10.0)	8.0 (26.7)
Child–Pugh at day 0 (n = %)
A	10 (16.7%)	7 (23.3%)	3 (10.0%)	0.313
B	43 (71.7%)	19 (63.3%)	24 (80.0%)
C	7 (11.7%)	4 (13.3%)	3 (10.0%)
SOFA at day 0 Median (range)	2.0 (1.0–7.0)	2.5 (1–7)	2.0 (1–7)	0.235
NRS 2002 at day 0 Median (Range)	2.0 (0.0–3.0)	2.0 (1.0–3.0)	2.0 (0.0–3.0)	0.964

All patients underwent total intravenous anaesthesia and there was no need for blood or blood products transfusion intraoperative. There were two patients who underwent laparoscopic resection in the control group; one of them was for hepatocellular carcinoma (HCC) in segment VII and the other was for hemangioma.

During the analysis of the BCAA group, we found that the actual applied time for BCAA infusion in the study has continued for 48 h in twenty-eight patients and for 72 h in two patients with a dose of 1gm/Kg/day.

Baseline readings of liver functions including AST, ALT, serum bilirubin, serum albumin, and prothrombin time were similar in both groups as shown in Table 2.

Table 2.

Liver function tests at the study baseline and subsequent days

	Total	BCAA	Placebo (Non BCAA)
Characteristic Median (range)				p-value
ALT (IU/L)
Day (0)	155.0 (35- 1490)	113.5 (48.0- 1490.0)	203.5 (35.0- 745.0)	0.068
Day (3)	111 (26–698)	88.5 (26–514)	170.5 (46–698)	0.050
Day (5)	89 (19–600)	80 (19–412)	123 (42–600)	0.007*
Day (7)	78 (25–360)	78 (25–206)	108.5 (48–360)	0.022*
AST (IU/L)
Day (0)	169.5 (61–988)	158.5 (61–988)	195 (64–850)	0.584
Day (3)	87 (21–684)	84 (21–684)	91.5 (23–662)	0.918
Day (5)	60 (19–380)	46 (19–320)	62 (22–380)	0.127
Day (7)	40 (17–340)	40 (17–340)	42 (17–340)	0.082
Bilirubin (mg%)
Day (0)	1.4 (0.2–11.0)	1.2 (0.3–11.0)	1.6 (0.2–10.2)	0.135
Day (3)	1.1 (0.3–11.1)	0.8 (0.3–11.1)	1.6 (0.4–10.9)	0.001*
Day (5)	0.8 (0.2–12.5)	0.3 (0.2–12.5)	2.2 (0.2–11.1)	0.002*
Day (7)	0.4 (0.3–9.2)	0.3 (0.3–4)	1.7 (0.3–9.2)	0.001*
PT (seconds)
Day (0)	16.85 (13–43.7	16.9 (13–43.7)	16.7 (13–31.9)	0.336
Day (3)	16 (12.7–41.8)	16 (13.2–41.8)	16.4 (12.7–28.5)	0.824
Day (5)	13.6 (12–56)	13.5 (12–56)	14.75 (12.9–27.8)	0.159
Day (7)	12.6 (11–27.9)	12.5 (11–23.5)	12.9 (11–27.9)	0.01*
Albumin (gm%)
Day (0)	3.1 (2.2–4.4)	3.2 (2.2–4.0)	3.1 (2.2–4.0)	0.853
Day (3)	3 (1.9–3.8)	3 (1.9–3.7)	3.05 (1.9–3.8)	0.557
Day (5)	2.8 (1.9–4)	2.8 (2–4)	2.85 (1.9–4)	0.858
Day (7)	3.1 (2.3–3.8)	3.1 (2.3–3.8)	3.1 (2.3–3.8)	0.669

Day 0 = immediately postoperative

^*statistically significant value

During follow-up, the total number of participants in both groups on days three, five, and seven were 54 (28 in the BCAA group and 26 in the placebo), 29 (15 in the BCAA group and 14 in the placebo), and 16 (6 in the BCAA group and 10 in the placebo) participants respectively and this was related to the stability of their medical and surgical condition so they were discharged from the institute.

To avoid overestimation of the results and to account for this dropout, an intention-to-treat analysis was employed. Missing data due to dropouts were addressed using a multiple imputation technique and the last observation carried forward (LOCF) method, ensuring that all participants were included in the final analysis.

Assessment for the impact of BCAA infusion on liver function tests during the first-week post-liver surgery, we observed that there was a significant decline of ALT on day five and day seven in the BCAA group compared to the control group (p-value = 0.007 and 0.002 respectively) and total bilirubin decline started from day three (p-value = 0.001). There was a significant improvement of PT on day seven 12.5 in the BCAA group versus 12.9 in the control group, p-value 0.01. Albumin did not show any significant difference among the two groups, as shown in Table 2 & Fig. 2A, B & C.

Fig. 2.

Diagrams A, B & C showing the median range of ALT, bilirubin & PT over the study period

The changes in liver enzyme levels from the baseline were as follows: the BCAA group experienced a 31.28% decrease in ALT levels, while the control group showed a reduction of 46.68%. For AST levels, the BCAA group observed a 74.76% decrease, compared to a 78.46% reduction in the control group. Total bilirubin levels decreased by 75% in the BCAA group, whereas the control group saw an increase of 6.25% from the baseline which was statistically significant (P value 0.0376). Additionally, prothrombin time (PT) declined by 26.03% in the BCAA group and by 22.75% in the control group.

Concerning follow-up, the complications and outcomes in Table 3; the infectious morbidity and duration of usage of antimicrobial showed no statistical difference among both groups. Regarding the non-infectious morbidity, the incidence of hyperglycemia and the need for insulin were similar among both groups.

Table 3.

Complications and outcomes among both arms of the study

	Total	BCAA	Placebo
Characteristic Median (range)				p-value
Duration of antimicrobials used (days)	4.0 (1.0–45.0)	5.0 (2.0–10.0)	4.0 (1.0–45.0)	0.969
Insulin units at day (3) Insulin at day (5) Insulin at day (7)	0.0 (0.0–41.0) 0.0 (0.0–15.0) 0.0 (0.0–5.0)	0.0 (0.0–15.0) 0.0 (0.0–15.0) 0.0 (0.0–5.0)	0.0 (0.0–41.0) 0.0 (0.0–0.0) 0.0 (0.0–0.0)	.9860 0.333 0.333
Child–Pugh score at day(7) (n = %)
A	11 (18.3%)	7 (23.3%)	4 (13.3%)
B	47 (78.3%)	22 (73.3%)	25 (83.3%)	0.604
C	2 (3.3%)	1 (3.3%)	1 (3.3%)
SOFA at day (7)	2 (1–9)	2 (1–9)	3.5 (1–9)	0.013*
NRS 2002 at day (7)	3 (1–5)	3 (1–4)	3 (1–5)	1.0
ICU stay (days)	2.0 (1.0–13.0)	2.0 (1.0–4.0)	3.0 (1.0–13.0)	0.018*
Hospital stay (days)	6.0 (2.0–47.0)	6.0 (3.0–14.0)	5.0 (2.0–47.0)	0.709
28-day mortality	2 (3.3)	1 ( 3.3)	1 ( 3.3)	–––-**

^*statistically significant value

^**The comparison could not be performed due to the small number of patients per group

Assessment of clinical scores on day seven SOFA score was markedly reduced in the BCAA group and was statistically significant; p-value 0.013.

Regarding the outcome; ICU stay was shorter in the BCAA group than the control group and was statistically significant; p-value 0.018.

Regarding 28-day mortality, there was a reported case of death in each group, both had underwent right formal hepatectomy for HCC; in the BCAA group the cause of death was pulmonary embolism and in the control group was acute liver cell failure. There is another patient in the control group who developed a surgical complication; portal vein thrombosis three weeks postoperative, so he underwent surgical intervention, reopened, and survived.

Discussion

The present study evaluated the use of BCAA in hepatic patients. It was found that ALT and bilirubin levels were decreased on day 5 and seven. This explained that BCAA may reduce liver cell apoptosis. As it enhanced hepatocyte regeneration and was associated with the increase of secretion of hepatocyte growth factor [12].Regarding albumin there was no difference between the two groups. The current result agrees with the previous study [13].It may be explained by a long half-life of albumin comparing to study duration. Another study showed that increased serum albumin in cirrhotic patients with serum albumin at 3.5 g/dL or less and the presence of ascites, peripheral edema, or hepatic encephalopathy [14]. Also another study showed that usage of BCAA decreased both ascites and pleural effusion [15].

Also, the improvement in the SOFA score at day 7 is related to a significant decrease in bilirubin value in the BCAA group. The improved liver enzymes and SOFA score will be reflected on less ICU stay in the study group.

Many studies proved that BCAA had an effect in improving hyperglycemia in cirrhotic patients, as it increases the liver X receptor/sterol regulatory element-binding protein-1c pathway, activates liver type glucokinase and glucose transporter, and suppress the hepatic expression ofglucose-6- phosphatase [3]. But in the current study, there was no difference between the study and the controlled groups. This may be explained by the short duration of therapy besides the cases involved in the study are post-surgery which had stress-induced hyperglycemia. Their low efficiency of the BCAA in disorders with the presence of SIRS is related to insulin resistance and metabolic alteration associated with inflammation. Studies have shown that inflammatory response blunts the anabolic response to BCAA administration [16].

One case developed hepatic encephalopathy in the control group. This goes with other studies that found BCAA will not improve hepatic encephalopathy but there will be less frequent development of hepatic encephalopathy [13, 17]. However, further researches with more sampling is needed to justify this concept post-liver surgery.

This is explained by concentrations of the aromatic amino acids (AAAs) are increased, in patients with advanced liver diseases, resulting in a low ratio of BCAA to AAAs, a ratio called the Fischer ratio. A low Fischer ratio was associated with hepatic encephalopathy. The imbalance of amino acids becomes manifested with the progression of liver diseases [18].

Limitation

• Single-center study.

• A further study is recommended to compensate for the dropouts that have been occurred during follow-up as patients were discharged from the institute according to the local protocol of discharge from hospital and the cause for these dropouts was that NHTMRI is a tertiary center specialized in liver surgeries up to liver transplant which is why we are receiving patients from different cities in Egypt and sometimes from other Arab countries, so patients were admitted to receive specialized services then discharged with the closed file system and can do follow up in other secondary hospitals, and to ask him to come to do follow up laboratory results in our center will be difficult for them.

• Short duration study. It was 7 days as the primary outcome was the impact of BCAAs on overall liver functions (AST, ALT, serum bilirubin & PT), Child–Pugh & SOFA scores. However, it needed to prolong the duration of the treatment to enable studying the impact on mortality and long-term benefits.

• The study collected different causes of liver surgery together, it is better in the future to enroll a specific liver surgery either for a benign or malignant cause.

Conclusion

BCAA infusion post-liver surgery has improved liver function tests markedly that was associated with improved SOFA score and shorter ICU stay. However, further multicenter studies are recommended to investigate the impact on hospital stay and mortality.

Abbreviations

BCAAs

Branched-chain amino acids

ICU

Intensive Care unit

NHTMRI

National hepatology and tropical medicine research institute

IRB

Institutional review board

BMI

Body mass index

DM

Diabetes mellitus

HTN

Hypertension

CLD

Chronic liver disease

SOFA

Sequential organ failure assessment

NRS

Nutritional Risk Screening

IV

Intravenous

AST

Aspartate aminotransferase (AST)

ALT

Alanine aminotransferase

PT

Prothrombin Time

AAAs

Aromatic amino acids

HCC

Hepatocellular carcinoma

Authors’ contributions

Eman I. El-Desoki Mahmoud performed conceptualization, data gathering, interpreting the results, and writing the original draft. Faten Farid Awdallah performed the review writing.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

The protocol was approved by the institutional review board of the national hepatology and tropical medicine research institute (NHTMRI), Cairo, Egypt. All study procedures were performed in accordance with good clinical practice and the declaration of Helsinki. Written informed consent was obtained from each patient or a legally authorized representative prior to enrollment in the study. The patients' information is kept confidential and not to be viewed except by those who are conducting the research. All patients have the right to refuse to continue the study at any time or not to be included from the start.

Competing interests

The authors declare no competing interests.