Fatigue in irritable bowel syndrome: characterization and putative role of leptin

OBJECTIVES

Fatigue has received little attention in the irritable bowel syndrome. Emerging evidence exists that leptin may be involved in the pathogenesis of fatigue in several conditions. We aimed to evaluate the occurrence of fatigue and its characteristics in irritable bowel syndrome and to analyze the relationship between fatigue and leptin.

METHODS

We enrolled 51 consecutive irritable bowel syndrome patients and 22 healthy controls without fatigue. None of them were depressed. The Fatigue Impact Scale was used to evaluate fatigue.

RESULTS

In all, 62.7% of irritable bowel syndrome patients verbally expressed fatigue and rated more than 4 on the visual analog scale. The total score of fatigue was significantly higher in irritable bowel syndrome than in controls. In irritable bowel syndrome patients, but not in controls, a significant association was found between the total score of fatigue and leptin and this association was more pronounced in 32 irritable bowel syndrome patients who verbally expressed fatigue (r=0.60; P=0.0003). In irritable bowel syndrome, leptin correlated with fatigue independently from age, sex, fat mass and body mass index.

CONCLUSIONS

Our study shows that fatigue occurs in 62.7% of irritable bowel syndrome patients when systematically asked for. Fatigue influences all three domains of the Fatigue Impact Scale in irritable bowel syndrome, the most being the physical and the psychosocial domains. Fatigue is associated with circulating leptin levels independently from age, sex, fat mass and body mass index in irritable bowel syndrome. The metabolic sequence involved in the occurrence of fatigue remains to be determined.

The severity of liver fibrosis is associated with high leptin levels in chronic hepatitis C

Recent attention has focused on the liver profibrogenic role of leptin in animal models. The purpose of this study was to evaluate the role of leptin and TNF-alpha in the severity of liver fibrosis in patients with chronic hepatitis C (CHC). We used a radioimmunoassay to determine serum leptin concentrations in 77 consecutive patients with CHC and 22 healthy controls. Leptin was correlated with liver histological (METAVIR) and metabolic indices. Sixty five patients had none to moderate liver fibrosis (F0-F2) and twelve severe fibrosis (F3-F4). Steatosis was observed in all but 27 patients. Leptin was significantly increased in patients compared with controls and was significantly more elevated in females both in patients and controls. The age, age at infection, prothrombin index, body mass index (BMI), triglycerides, glycaemia, ferritin, leptin and TNF-alpha, were associated with severe fibrosis. Steatosis was significantly more pronounced in patients with severe than those without or moderate fibrosis (P = 0.04). Only leptin was significantly and independently associated with severe fibrosis (OR = 1.2, CI 95%: 1.1-1.4, P = 0.03). Leptin was significantly associated with BMI (r = 0.64, P < 0.001) and glycaemia (r = 0.43, P < 0.001). Significant correlations were found between steatosis and BMI (r = 0.30, P < 0.01) and glycaemia (r = 0.30, P < 0.01). In patients with CHC and higher BMI and glycaemia levels, the severity of liver fibrosis is associated with serum leptin. TNF-alpha is a putative candidate involved in the mechanism.

Chondrex (YKL-40), a potential new serum fibrosis marker in patients with alcoholic liver disease

OBJECTIVES

Chondrex (YKL-40) is a mammalian member of a protein family that includes bacterial chitinases. The pattern of its expression in certain tissues such as human liver or cartilage suggests a function in remodelling or degradation of extracellular matrix. The purpose of this study was to assess whether circulating YKL-40 might be a serum fibrosis marker in alcoholics.

METHODS

Plasma YKL-40 was determined in 146 consecutive heavy drinkers (106 men, 40 women; mean age, 49.2 +/- 9.0 years). Liver biochemical parameters and serum fibrosis markers such as hyaluronate were also measured. Fibrosis and inflammation in liver biopsy were evaluated using a semi-quantitative scoring system.

RESULTS

Plasma YKL-40 increased in parallel with the severity of fibrosis (P<0.00001). YKL-40 also increased in the presence of hepatic inflammation (P<0.01). Receiver operating characteristic curves of Chondrex revealed that a threshold of 330 microg/l gave a specificity of 88.5%; however, the sensitivity was only 50.8%. Only 11.5% of patients without severe fibrosis displayed a Chondrex plasma level above this threshold. A positive correlation was found between Chondrex and hyaluronate (r=0.40, P<0.0001), and a negative correlation was shown between Chondrex and the prothrombin index (r=-0.37, P<0.0001).

CONCLUSIONS

The severity of liver fibrosis is associated with elevated circulating Chondrex levels. The overlap in YKL-40 values prevents use of Chondrex in a screening programme. High levels of Chondrex (above 330 microg/l) are predictive of severe liver fibrosis. Increased plasma YKL-40 may reflect the remodelling of liver fibrosis in alcoholics.

Non invasive prediction of severe fibrosis in patients with alcoholic liver disease

OBJECTIVES

The aim of this study was to assess the diagnostic accuracy of noninvasive markers of liver fibrosis in alcoholic liver disease.

PATIENTS AND METHODS

Fifty-four clinical and biochemical parameters including serum fibrosis markers (hyaluronate and transforming growth factor beta1) were analyzed in 146 consecutive heavy drinkers (106 men, 40 women; mean age 49.2 years). Following liver biopsy, fibrosis was evaluated using a semi-quantitative scoring system (no fibrosis (0) to severe fibrosis (3 + )). Multivariate analysis was performed to determine the markers that were best correlated with the fibrosis score.

RESULTS

Fifty-nine patients (40.4 %) had severe fibrosis (3 +) while 87 (59.6 %) had no fibrosis or moderate fibrosis (0 to 2 +). In multivariate analysis, serum hyaluronate and the prothrombin index were the best markers for the prediction of severe fibrosis. Hyaluronate and the prothrombin index had a diagnostic accuracy of 91.1 % and 89.7 %, respectively in the whole population. Finally, a significant negative correlation was found between hyaluronate and the prothrombin index (r =- 0.86, P <0.0001).

CONCLUSIONS

Using only hyaluronate and the prothrombin index, 9 out of 10 alcoholic patients can be correctly classified according to the severity of liver fibrosis.