Inducibility of microsomal liver function may differentiate cirrhotic patients with maintained compared with severely compromised liver reserve

European guideline on indications, performance and clinical impact of 13 C-breath tests in adult and pediatric patients: An EAGEN, ESNM, and ESPGHAN consensus, supported by EPC

Introduction

¹³C‐breath tests are valuable, noninvasive diagnostic tests that can be widely applied for the assessment of gastroenterological symptoms and diseases. Currently, the potential of these tests is compromised by a lack of standardization regarding performance and interpretation among expert centers.

Methods

This consensus‐based clinical practice guideline defines the clinical indications, performance, and interpretation of ¹³C‐breath tests in adult and pediatric patients. A balance between scientific evidence and clinical experience was achieved by a Delphi consensus that involved 43 experts from 18 European countries. Consensus on individual statements and recommendations was established if ≥ 80% of reviewers agreed and <10% disagreed.

Results

The guideline gives an overview over general methodology of ¹³C‐breath testing and provides recommendations for the use of ¹³C‐breath tests to diagnose Helicobacter pylori infection, measure gastric emptying time, and monitor pancreatic exocrine and liver function in adult and pediatric patients. Other potential applications of ¹³C‐breath testing are summarized briefly. The recommendations specifically detail when and how individual ¹³C‐breath tests should be performed including examples for well‐established test protocols, patient preparation, and reporting of test results.

Conclusion

This clinical practice guideline should improve pan‐European harmonization of diagnostic approaches to symptoms and disorders, which are very common in specialist and primary care gastroenterology practice, both in adult and pediatric patients. In addition, this guideline identifies areas of future clinical research involving the use of ¹³C‐breath tests.

Non-Alcoholic Steatohepatitis Decreases Microsomal Liver Function in the Absence of Fibrosis

The incidence of non-alcoholic fatty liver disease (NAFLD) is rising across the globe, with the presence of steatohepatitis leading to a more aggressive clinical course. Currently, the diagnosis of non-alcoholic steatohepatitis (NASH) is based on histology, though with the high prevalence of NAFLD, a non-invasive method is needed. The 13C-aminopyrine breath test (ABT) evaluates the microsomal liver function and could be a potential candidate. We aimed to evaluate a potential change in liver function in NASH patients and to evaluate the diagnostic power of ABT to detect NASH. We performed a retrospective analysis on patients suspected of NAFLD who underwent a liver biopsy and ABT. 440 patients were included. ABT did not decrease in patients with isolated liver steatosis but decreased significantly in the presence of NASH without fibrosis and decreased even further with the presence of significant fibrosis. The predictive power of ABT as a single test for NASH was low but improved in combination with ALT and ultrasonographic steatosis. We conclude that microsomal liver function of patients with NASH is significantly decreased, even in the absence of fibrosis. The ABT is thus a valuable tool in assessing the presence of NASH; and could be used as a supplementary diagnostic tool in clinical practice.

Design of liver functional reserve monitor based on three-wavelength from red light to IR

BACKGROUND

The preoperative evaluation of liver functional reserve is very important to determine the excision of liver lobe for the patients with liver cancer. There already exist many effective evaluation methods, but these ones have many disadvantages such as large trauma, complicated process and so on.

OBJECTIVE

Therefore, it is essential to develop a fast, accurate and simple detection method of liver functional reserve for the practical application in the clinical engineering field.

METHODS

According to the principle of spectrophotometry, this paper proposes a detection method of liver functional reserve based on three-wavelength from red light to infrared light (IR), in which the artery pulse, the vein pulse and the move of tissue are taken into account.

RESULTS

By using photoelectric sensor technology and excreting experiment of indocyanine green, a minimally invasive, fast and simple testing equipment is designed in this paper.

CONCLUSIONS

The testing result shows this equipment can greatly reduce the interference from human body and ambient, realize continuous and real-time detection of arterial degree of blood oxygen saturation and liver functional reserve.

Noninvasive assessment of liver function

PURPOSE OF REVIEW

It is our opinion that there is an unmet need in hepatology for a minimally or noninvasive test of liver function and physiology. Quantitative liver function tests define the severity and prognosis of liver disease by measuring the clearance of substrates whose uptake or metabolism is dependent upon liver perfusion or hepatocyte function. Substrates with high-affinity hepatic transporters exhibit high 'first-pass' hepatic extraction and their clearance measures hepatic perfusion. In contrast, substrates metabolized by the liver have low first-pass extraction and their clearance measures specific drug metabolizing pathways.

RECENT FINDINGS

We highlight one quantitative liver function test, the dual cholate test, and introduce the concept of a disease severity index linked to clinical outcome that quantifies the simultaneous processes of hepatocyte uptake, clearance from the systemic circulation, clearance from the portal circulation, and portal-systemic shunting.

SUMMARY

It is our opinion that dual cholate is a relevant test for defining disease severity, monitoring the natural course of disease progression, and quantifying the response to therapy.

13C-methacetin breath test for evaluation of liver functional reserve and treatment effectiveness in patients with liver cirrhosis

AIM: To evaluate the value of ¹³C-methacetin breath test in diagnosis and treatment of liver cirrhosis and the association between Child-Pugh score and ¹³C-MBT, and to analyze their advantages and disadvantages.

METHODS: Eighty-eight inpatients and 10 healthy volunteers were enrolled. All of them received ¹³C-MBT and Child-Pugh scoring. According to ¹³C-MBT levels, 88 patients with liver cirrhosis were divided into three subgroups: levelsⅠ(n = 21), Ⅱ(n = 36), and Ⅲ (n = 31). According to Child-Pugh score, the patients were also divided into three subgroups: grade A in 16 cases, grade B in 41 cases and grade C in 31 cases. Liver function changes between before and after treatment were assessed. Sensitivity, specificity and time required to achieve efficacy between two groups were compared.

RESULTS: There was a good consistency (Kappa = 0.84, P < 0.05) between ¹³C-MBT levels (levels Ⅰ, Ⅱ and Ⅲ) and Child-Pugh score (grades A, B and C). Sensitivity and specificity of 13C-MBT were similar to those of Child-Pugh score (93.8%, 75.6%, 87.1% vs 91.7%, 89.4%, 93.0%). Concerning the time required to achieve efficacy, according to Child-Pugh score, there was no statistic significance among three subgroups of patients (P > 0.05), while according to ¹³C-MBT levels, a statistic significance was observed among the three subgroups of patients (P < 0.05). The higher the ¹³C-MBT level, the shorter the time required to achieve efficacy.

CONCLUSION: ¹³C-MBT is a simple, safe and reliable technique, representing a complementary method for Child-Pugh scoring.

Evaluation of quantitative liver function tests in HIV-positive patients under anti-retroviral therapy

Background and aims

Quantitative tests of liver function (QTLF) which are based on the hepatic metabolism or clearance of test substances have been successfully used to predict prognosis of a variety of different liver diseases. Still sufficient data in HIV-patients under anti-retroviral therapy (ART) are lacking. Therefore, the aim of this prospective study was to investigate if and to what extent ART influences a broad panel of quantitative tests of liver function in patients with HIV-infection.

Patients and methods

Nineteen patients (14 males, 5 females, mean age 40 years) with HIV-infection underwent QTLF including lidocaine half-life test (LHT), galactose elimination capacity (GEC), and indocyanine green clearance (IGC). These tests were performed before and 3 to 6 months after initiation of anti-retroviral therapy. Twenty age-matched healthy, medication-and virus-free adults served as controls.

Results

Lidocaine half-life was significantly lower in HIV-patients without ART. Combining anti-retroviral therapies shifted cytochrome p450 activity back into standard ranges. Galactose elimination capacity as a parameter of cytosolic liver function and indocyanine green clearance as a parameter of liver perfusion were not affected by ART.

Conclusions

QTLF may be a tool to predict prognosis or hepatic complications in HIV-infected patients with liver disease. Early determination of lidocaine half-life seems to be useful - this should be considered during the treatment of HIV-positive individuals.

[Breath tests in the diagnosis of gastrointestinal diseases]

Determination of carbon or hydrogen markers in breath has allowed closer investigation of the pathogenic mechanisms of several gastrointestinal diseases. Thus, the 13C-urea breath test is a nonaggressive, simple and safe test with excellent accuracy both in the initial diagnosis of Helicobacter pylori infection and in confirmation of its eradication following treatment. Moreover, because of the simplicity, reproducibility and safety of these types of procedure, they have tended to substitute more uncomfortable and expensive techniques that were traditionally used in gastroenterology. Several breath tests have been developed that allow reliable evaluation of liver or exocrine pancreatic function, gastrointestinal motility, as related to gastric emptying or orocecal transit time, and a diagnostic approach to clinical problems that could be due to bacterial overgrowth or malabsorption of various sugars.

Improvement of quantitative testing of liver function in patients with chronic hepatitis C after installment of antiviral therapy

AIM: To investigate if and to what extent antiviral therapy influenced a broad panel of quantitative testing of liver function (QTLF).

METHODS: Fifty patients with chronic hepatitis C were either treated with interferon (n = 8), interferon/ribavirin (n = 19) or peg-interferon/ribavirin (n = 23). Quantitative testing of liver function, including aminopyrine breath test (ABT), galactose elimination capacity (GEC), sorbitol clearance (SCl) and indocyanine green clearance (ICG) was performed before and 3 mo after initiation of antiviral therapy.

RESULTS: After 3 mo of antiviral treatment, 36 patients showed normal transaminases and were negative for HCV-RNA, 14 patients did not respond to therapy. ABT and GEC as parameters of microsomal and cytosolic liver function were reduced in all patients before therapy initiation and returned to normal values in the 36 therapy responders after 3 mo. Parameters of liver perfusion (SCl and ICG) were not affected by antiviral therapy. In the 14 non-responders, no changes in QTLF values were observed during the treatment period.

CONCLUSION: ICG and SCl remained unaffected in patients with chronic hepatitis C, while ABT and GEC were significantly compromised. ABT and GEC normalized in responders to antiviral therapy. Early determination of ABT and GEC may differentiate responders from non-responders to antiviral treatment in hepatitis C.

13C- mithacetin breath test for assessment of liver functional capacity

AIM: To investigate the clinical significance of ¹³C-mithacetin breath tests for assessment and the classification of liver functional capacity.

METHODS: Twelve healthy volunteers served as a control group. Patients (test group) with different kinds of liver diseases were divided into 4 sub-groups: compensatory period (n = 4), Child-Pugh classification A, B, C (n = 12, 12, 16, respectively). Patients in both groups were examined for liver function by a biochemical test after orally taking ¹³C-mithacetin (75 mg). Gas breathed out was collected at 9 different time within 120 min. The samples were analyzed with mass spectrograph to obtain DOB, MV and CUM curves and CUM120 value.

RESULTS: Biochemical index such as ALB and pre-albumin (PA) in patients of test group (Child-Pugh A, B and C) were significantly decreased as compared with those in patients of control group (ALB: 33.1 ± 3.1, 29.3 ± 6.5, 27.9 ± 5.0 vs 36.6 ± 4.7; PA: 119.7 ± 51.0, 104.3 ± 21.1, 77.4 ± 32.9 vs 176.4 ± 68.2; P < 0.05). The classifications of liver capacity significantly related to the values of ALB and PA (P < 0.05). Peak values of DOB and MV curves negatively related to the peak time in the test group (DOB: r = -0.48, P < 0.01; MV: r = -0.57, P < 0.01). Peak values of DOB, MV and CUM decreased with the development of liver dysfunction. Significant difference existed between the test group (Child-Pugh A, B, and C respectively) and control group (DOB: 10.4 ± 3.39, 6.71 ± 3.58, 4.00 ± 1.40 vs 20.93 ± 7.56; MV: 13.12 ± 9.51, 11.61 ± 8.02, 10.20 ± 4.99 vs 29.53; CUM: 18.09 ± 18.09, 16.60 ± 16.60, 15.82 ± 15.82 vs 30.67 ± 2.85; P < 0.05 repectively). CUM120 values in patients of the test group (Child-Pugh A, B, and C) significantly decreased as compared with those in patients of control group (63.61 ± 36.67, 59.32 ± 24.73, 52.62 ± 23.92 vs 109.45 ± 10.26; P < 0.05), but no significant decrease appeared among sub-groups.

CONCLUSION: ¹³C-mithacetin breath test is a safe, effective method in assessment and classification of liver capacity. Mean peak values of DOB, MV and CUM curves and CUM120 value decrease with the development of liver dysfunctions. Peak values are more clinically significant than peak time.

Validity of the 13C-caffeine breath test as a noninvasive, quantitative test of liver function

The properties of caffeine render it an ideal substrate for a quantitative test of liver function. The aim of this study was to determine whether the caffeine breath test (CBT) using orally administered 13C-caffeine correlates reliably with plasma caffeine clearance and reflects varying degrees of liver dysfunction. The CBT was performed in 25 healthy controls; 20 subjects with noncirrhotic, chronic hepatitis B or C; and 20 subjects with cirrhosis. Plasma caffeine clearance was assayed simultaneously with the CBT in a cohort of these subjects. Over a broad range of caffeine clearances, the CBT exhibited a highly significant correlation with plasma clearance (r = 0.85, P <.001). Cirrhotic patients were characterized by significantly reduced CBT values (1.15 +/- 0.75 delta per thousand mg(-1)) compared with controls (2.23 +/- 0.76; P =.001) and hepatitic patients (1.83 +/- 1.05; P =.04). There was a significant inverse relationship between the CBT and Child-Pugh score (r = -.74, P =.002). The intraclass correlation coefficient between repeated CBTs in 20 subjects with normal and cirrhotic livers was 0.89. Although smoking was associated with an 86% to 141% increase in CBT in all groups, the CBT was able to distinguish control, hepatitic, and cirrhotic smokers (5.36 +/- 0.82, 3.63 +/- 1.21, and 2.14 +/- 1.14, respectively, P =.001). Multivariate analysis revealed that only smoking (P <.001) and disease state (P =.001) were significant predictors of the CBT. In conclusion, the 13C-CBT represents a valid indicator of plasma caffeine clearance and correlates reproducibly with hepatic dysfunction.