Aminopyrine breath test

Peripheral and Hepatic Vein Cytokine Levels in Correlation with Non-Alcoholic Fatty Liver Disease (NAFLD)-Related Metabolic, Histological, and Haemodynamic Features

BACKGROUND

Haemodynamic impairment, inflammatory mediators and glucose metabolism disturbances have been implicated in the pathogenesis of Non-Alcoholic Fatty Liver Disease (NAFLD).

AIM

To investigate the cytokine profile in NAFLD patients in peripheral (P) and hepatic venous (HV) blood and to compare with histology, haemodynamic and metabolic parameters.

METHODS

40 obese patients with an indication for a transjugular liver biopsy were enrolled. Besides an extended liver and metabolic work-up, interleukin (IL) 1B, IL4, IL6, IL10, IL23, tumour necrosis factor (TNF) α and interferon (INF) γ were measured in plasma obtained from P and HV blood by means of multiplex immunoassay. The T helper (Th)1/Th2, the macrophage M1/M2 and the IL10/IL17a ratios were calculated.

RESULTS

A decrease of the P-IL10/IL17-ratio and an increase of the P-M1/M2-ratio (p<0.05) were observed in NASH versus no-NASH patients. A P-M1/M2-ratio increase was detected also in patients with portal hypertension in comparison with patients without it (p<0.05). Moreover diabetic patients showed an increase of the P-Th1/Th2-ratio in comparison with non-diabetic ones (p<0.05). The P-M1/M2 ratio positively correlated with steatosis grade (r = 0.39, p = 0.02) and insulin (r = 0.47, p = 0.003). The HV-M1/M2 ratio positively correlated with fasting insulin and Hepatic Venous Pressure Gradient (r = 0.47, p = 0.003). IL6 correlated with the visceral fat amount (r = 0.36, p = 0.02). The P- and HV-IL10/IL17 ratios negatively correlated with fasting insulin (respectively r = -0.4, p = 0.005 and r = 0.4, p = 0.01).

CONCLUSIONS

A proinflammatory cytokine state is associated with more disturbed metabolic, histological, and haemodynamic features in NAFLD obese patients. An increase of the M1/M2 ratio and a decrease of the IL10/IL17 ratio play a key role in this process.

A comparison of the reproducibility of the parameters of the ¹³C-aminopyrine breath test for the assessment of hepatic function

This study determined the within-subject and between-subject variability of different ways of expressing the results of the (13)C-aminopyrine breath test ((13)C-ABT) and the effect of shortening the test duration. The (13)C-ABT was conducted on three separate occasions in 10 healthy volunteers and on a single occasion in 22 patients with established liver cirrhosis. The within-subject variability of cumulative percentage dose recovered (cPDR), using measured CO(2) production rate (VCO(2)), in the reference group over three trials was 15% over 120 min. Higher within-subject variability in cPDR would have been evident if the test was terminated at either 30 or 60 min. Substitution of predicted VCO(2) to calculate cPDR yielded comparable values at all time points. Significant differences between cirrhotics and reference group were evident after just 10 min using PDR/h, cPDR or enrichment (all P<0.05). The ABT demonstrates clinically acceptable reproducibility. Shortening of the duration may make the test more acceptable clinically, but it is associated with increasing imprecision.

Measurement of hepatic functional mass by means of 13C-methacetin and 13C-phenylalanine breath tests in chronic liver disease: Comparison with Child-Pugh score and serum bile acid levels

AIM: To evaluate and compare the clinical usefulness of ¹³C-phenylalanine and ¹³C-methacetin breath tests in quantitating functional hepatic mass in patients with chronic liver disease and to further compare these results with those of conventional tests, Child-Pugh score and serum bile acid levels.

METHODS: One hundred and forty patients (50 HCV- related chronic hepatitis, 90 liver cirrhosis patients) and 40 matched healthy controls were studied. Both breath test and routine liver test, serum levels of cholic and chenodeoxycholic acid conjugates were evaluated.

RESULTS: Methacetin breath test, expressed as 60 min cumulative percent of oxidation, discriminated the hepatic functional capacity not only between controls and liver disease patients, but also between different categories of chronic liver disease patients. Methacetin breath test was correlated with liver function tests and serum bile acids. Furthermore, methacetin breath test, as well as serum bile acids, were highly predictive of Child-Pugh scores. The diagnostic power of phenylalanine breath test was always less than that of methacetin breath test.

CONCLUSION: Methacetin breath test represents a safe and accurate diagnostic tool in the evaluation of hepatic functional mass in chronic liver disease patients.

13C-aminopyrine breath test to evaluate severity of disease in patients with chronic hepatitis C virus infection

BACKGROUND

There are few data on the use of the 13C-aminopyrine breath test to evaluate the severity of disease in patients with hepatitis C virus-related chronic liver disease, although these patients represent one of the most important problems in clinical hepatology.

AIMS

To compare 13C-aminopyrine breath test results of patients with hepatitis C virus-related chronic hepatitis and Child-Pugh class A cirrhosis with those of normal subjects, and to evaluate different methods of expressing 13C-aminopyrine breath test results.

METHODS

Twenty-four patients with hepatitis C virus-related chronic hepatitis and 17 patients with Child-Pugh class A cirrhosis underwent 13C-aminopyrine breath test. Breath samples were collected every 30 min up to 2 h after 13C-aminopyrine administration. 13C-Aminopyrine breath test results were expressed as a percentage of the administered dose of 13C recovered per hour (% dose/h) and the cumulative percentage of administered dose of 13C recovered over time (% dose cum). Nineteen healthy subjects served as controls. Patients with hepatitis C virus-related chronic hepatitis were divided into subgroups on the basis of histological staging and grading.

RESULTS

The 13C-aminopyrine breath test result (% dose/h) at 30 min was significantly different among the three subgroups of subjects (normal subjects, 11.5 +/- 3.5; chronic hepatitis patients, 8.1 +/- 4.1; cirrhosis patients, 5.0 +/- 3.1; P < 0.0005). Moreover, the differences between chronic hepatitis and cirrhosis patients were statistically significant (P < 0.03). The fibrosis score showed a significant inverse correlation with the 13C-aminopyrine breath test result (% dose/h) at 30 min (rs=- 0.409, P=0.05). The 13C-aminopyrine breath test result (% dose/h) at 30 min also allowed normal subjects and chronic hepatitis patients with low (< or = 2) or high (> 2) fibrosis scores to be distinguished. The 13C-aminopyrine breath test results (% dose cum) at 30, 60 and 90 min allowed discrimination between normal subjects and chronic hepatitis and cirrhosis patients. The 13C-aminopyrine breath test result (% dose cum) was also able to distinguish between normal subjects and chronic hepatitis patients with high but not low fibrosis scores. Both 13C-aminopyrine breath test results (% dose/h and % dose cum) at 120 min allowed the differentiation between normal subjects and chronic hepatitis patients with high (> or = 6) necro-inflammatory activity.

CONCLUSIONS

In patients with hepatitis C virus-related chronic liver disease, the 13C-aminopyrine breath test proved to be safe and easy to perform, and was able to evaluate different degrees of liver function impairment which were partly correlated to clinical and histological evaluation. In future studies, 13C-aminopyrine breath test results should be expressed in a standardized fashion to permit comparison.