Analysis of the deterioration rates of liver function in cirrhosis, based on galactose elimination capacity

Body composition changes after transjugular intrahepatic portosystemic shunt in patients with cirrhosis

AIM: To investigate the effect of transjugular intrahepatic porto-systemic shunt (TIPS) on malnutrition in portal hypertensive cirrhotic patients.

METHODS: Twenty-one patients with liver cirrhosis and clinical indications for TIPS insertion were investigated before and 1, 4, 12, 52 wk after TIPS. For each patient we assayed body composition parameters [dry lean mass, fat mass, total body water (TBW)], routine liver and kidney function tests, and free fatty acids (FFA). Glucose and insulin were measured for the calculation of the homeostasis model assessment insulin resistance (HOMA-IR); liver function was measured by the galactose elimination capacity (GEC); the severity of liver disease was graded by model for end-stage liver disease (MELD).

RESULTS: Porto-systemic gradient decreased after TIPS (6.0 ± 2.1 mmHg vs 15.8 ± 4.8 mmHg, P < 0.001). Patients were divided in two groups according to initial body mass index. After TIPS, normal weight patients had an increase in dry lean mass (from 10.9 ± 5.9 kg to 12.7 ± 5.6 kg, P = 0.031) and TBW (from 34.5 ± 7.6 L to 40.2 ± 10.8 L, P = 0.007), as well as insulin (from 88.9 ± 49.2 pmol/L to 164.7 ± 107.0 pmol/L, P = 0.009) and HOMA-IR (from 3.36% ± 2.18% to 6.18% ± 4.82%, P = 0.023). In overweight patients only FFA increased significantly (from 0.59 ± 0.24 mmol/L to 0.93 ± 0.34 mmol/L, P = 0.023).

CONCLUSION: TIPS procedure is effective in lowering portal pressure in patients with portal hypertension and improves body composition without significant changes in metabolic parameters.

Review article: breath testing for human liver function assessment

Carbon-labelled breath tests were proposed as tools for the evaluation of human liver function 30 years ago, but have never become part of clinical routine. One reason for this is the complex role of the liver in metabolic regulation, making it difficult to provide essential information for the management of patients with liver disease with a single test and to satisfy the hepatology community. As a result, a battery of breath tests have been developed. Depending on the test compound administered, different metabolic pathways (microsomal, cytosolic, mitochondrial) can be examined. Most available data come from microsomal function tests, whilst information about cytosolic and mitochondrial liver function is more limited. However, breath tests have shown promise in some studies, in particular to predict the outcome of patients with chronic liver disease or to monitor hepatic function after treatment. Whilst we await new substrates that can be used to measure liver function in a more valid manner, and large prospective studies to assess the usefulness of available test compounds, the aim of this review is to describe how far we have come in this controversial and unresolved issue.

The monoethylglycinexylidide test for grading of liver cirrhosis

BACKGROUND

Monoethylglycinexylidide (MEGX) formation following lignocaine injection has recently been proposed as a simple dynamic liver function test based on a single measurement of its serum concentration.

AIM

To determine the optimal sampling time for MEGX determination.

METHODS

A modelling analysis of lignocaine and MEGX kinetics was performed in seven normals and in four patients with compensated liver cirrhosis; a similar study was performed in 74 cirrhotic patients, divided into two groups according to disease severity (Pugh score).

RESULTS

Only the MEGX fractional formation rate (kf) and formation delay (tau) were significantly altered in cirrhotic patients compared to normals: kf = 0.15 +/- 0.03 vs. 0.32 +/- 0.10 min-1 (mean +/- s.d.); tau = 7.7 +/- 2.0 vs. 3.9 +/- 2.9 min-1. A good correlation was found between kf and late (r = 0.82) but not early (r = 0.63) serum MEGX formation, suggesting that late measurements for the clinical MEGX test are preferred. In the second part of our investigation, by discriminant analysis of MEGX test data for 74 cirrhotic patients, the late MEGX concentrations gave the best discrimination between the two classes. In particular, the 60 min MEGX concentration showed the best diagnostic accuracy (81%), sensitivity (75%) and specificity (84%). The association of this with other MEGX parameters, either singly or derived from the whole curve measurements, did not improve the performance of the method.

CONCLUSION

The MEGX test, based on a single determination 60 min after lignocaine injection, may be regarded as a simple and sensitive quantitative liver function test.

Echo enhancers and ultrasound imaging

The quality of diagnostic ultrasound images is sometimes limited by excessive acoustic attenuation within the organs and tissues. Ultrasound echo-enhancers help to overcome that limitation by increasing the intensity of the reflected signal. Acoustic principles dictate that the most effective enhancers are gas-filled microbubbles. The problem of producing a microbubble suspension stable enough for routine clinical use has been overcome in several ways. Newer developments are leading to enhancers with an active acoustic response and that have affinities for specific organs and tissues.

Glutathione kinetics in normal man and in patients with liver cirrhosis

BACKGROUND/AIMS

The dynamics of glutathione in plasma has always been studied by bolus injections. Data are available suggesting that the low plasma levels of cirrhosis are due to decreased production in glutathione-producing tissues, mainly the liver. We aimed to measure the kinetics of glutathione during controlled steady-state conditions, and to determine the reasons for its reduced plasma levels in advanced cirrhosis.

METHODS

The plasma clearance of glutathione was measured in six control subjects and in ten patients with cirrhosis during a 2-step infusion study, producing steady-state levels approximately 5 and 10 times basal values. The plasma disappearance curve after infusion stop was used to determine the apparent volume of distribution and half-life of glutathione, and the estimated basal appearance rate.

RESULTS

The clearance of glutathione did not reject 1st-order kinetics, i.e., it was concentration-independent, and was nearly doubled in cirrhosis. The half-life of exogenous glutathione was not different, whereas the volume of distribution was larger in cirrhosis, in the same range as extracellular water. The endogenous basal appearance rate of glutathione was reduced by 50%, and correlated with liver function, measured by routine and dynamic tests.

CONCLUSIONS

The data confirm that the primary defect responsible for reduced glutathione in liver disease is a reduced production, possibly related to hepatocyte dysfunction and a block along the pathway of methionine metabolism.

Liver function tests

For optimal timing of liver transplantation and for the evaluation of new pharmacotherapeutic options, objective modalities for estimating the liver's functional reserve and prognosis in an individual patient are highly desirable. In the past a number of tests and several scoring systems have been proposed and validated to varying degrees for this purpose. The issues still to be clarified include: (1) any observed prognostic value of individual quantitative function tests and of scoring systems must be validated in independent, large enough and well defined patient populations; (2) it must be prospectively defined which (serially performed) quantitative test(s) add(s) prognostic information for the individual patient to the survival estimates defined by the more universally available scores and in which disease state(s); and (3) existing scoring systems must be validated, or new ones developed, that allow follow-up data to be used in order to adapt the original prognosis estimate to the evolution of the disease, e.g. during therapy.

A simplified method to determine galactose elimination capacity in patients with liver disease

Galactose elimination capacity (GEC) is one of the most widely used liver function tests. It is relatively simple but still involves a number of capillary blood samples and is therefore fairly expensive. In the current study we present a simplified formula, based on GEC investigations in 103 cirrhotic patients, with which it is possible to estimate the GEC with one or two blood samples. Using this formula: GEC = [7.422--corrected B-galactose60 min]/4.575, we could accurately predict GEC in 24 additional patients.

Thyroid gland size and function in patients with cirrhosis of the liver

Thyroid dysfunction has long been reported in patients with liver disease, but limited information is available on thyroid gland size in cirrhosis. Most studies were carried out on small, selected series of patients, and no study has measured thyroid volume in relation to the etiology of liver disease. Thyroid volume was measured at ultrasound in 118 consecutive patients with cirrhosis of different etiology and 48 healthy subjects matched for age and sex. No subjects had evidence of overt thyroid disease. The mean volume was increased by 17% (from 16.0 [SD 5.2] ml in controls to 18.8 [7.6] in cirrhosis; P less than 0.025), and thyroid enlargement (antero-posterior diameter greater than 20 mm) was present in 38% of cases, in the presence of hormone values indicative of low-T3 syndrome. No significant differences in thyroid gland size were observed in relation to the extent of liver dysfunction or to the etiology of liver disease. The prevalence of thyroid nodules was similar in controls and in patients with cirrhosis. In only 8% of cases were laboratory values indicative of hypothyroidism, with low free triiodothyronine and raised thyroid-stimulating hormone levels; in these patients thyroid volume was decreased on average by 26%. This was mainly the case with patients with primary biliary and alcoholic cirrhosis. The largest mean thyroid volume was observed in patients with HBsAg + ve postnecrotic cirrhosis, whose thyroid volume was increased on average by 37%, and 53% of subjects had thyroid enlargement. This finding raises the question of a possible direct involvement of the thyroid in hepatitis B virus infection.