Abstract and Introduction
Abstract
Aim. Serum carnitine level and its associated factors have been evaluated in patients with chronic viral hepatitis.
Methods. Patients with confirmed chronic viral hepatitis based on the serological markers and liver biopsy were included. In total, 86 volunteers and 86 patients with chronic viral hepatitis completed the study. Demographic data, type of treatment regimen and nutritional status of the patients were recorded and one blood sample was collected from each patient after an overnight fasting. A double antibody sandwich ELISA kit was used to measure carnitine serum level.
Results. Mean ± standard deviation of serum carnitine level in the case and control groups were 34.3 ± 15.3 and 55.7 ± 28.4 μmol/l, respectively (p = 0.001). Regarding carnitine deficiency definition, 64 out of 86 patients (74.4%) and 21 out of 86 (24.5%) healthy individuals suffered from carnitine deficiency (p < 0.001). Carnitine dietary intake was significantly lower (p < 0.001). Compared with patients with chronic hepatitis C infection, a more severe form of carnitine deficiency was detected in patients with chronic hepatitis B infection (18.39 ± 15.68 μmol/l vs 42.30 ± 32.92 μmol/l; p = 0.03). In addition, serum carnitine level (41.1 ± 14.8 μmol/l) was significantly higher in the cirrhotic than noncirrhotic patients (31.60 ± 13.2 μmol/l; p = 0.04).
Conclusion. Although the cirrhotic patients had higher serum carnitine level compared with noncirrhotic patients, serum carnitine level in the patients with chronic hepatitis was significantly lower than the healthy individuals. Also compared with the defined cut-off point for normal carnitine serum level, carnitine deficiency was common in Iranian patients with chronic hepatitis.
Introduction
Viral hepatitis is a common infection in the developing countries. Five distinct viruses are responsible for inflammation of hepatocytes: hepatitis A virus, hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus and hepatitis E virus. Among them, HBV and HCV are the leading causes of cirrhosis and hepatocellular carcinoma worldwide.[1,2]
The prevalence of hepatitis B in Europe and the USA was reported to be 0.2–7% and 0.4–0.5%, respectively. In Asia and Africa, known as the highest endemic areas, the prevalence reaches up to 20%.[3] In 2005, it was estimated that approximately 185 million people were infected with HCV globally.[4] The latest epidemiological study in Iran in 2010 announced the prevalence rate to be 3% for hepatitis B and 0.5% for hepatitis C.[5]
Carnitine is a nonessential amino acid, which is synthesized endogenously from lysine and methionine,[6] along with the amount exogenously absorbed from the small intestine.[7] The kidney, liver and brain are the main organs for carnitine synthesis in the human body but most of the body's carnitine requirement is obtained from food.[8] Carnitine has a vital role in β-oxidation and energy production in all body tissues and is provided by liver and kidney biosynthesis and alimentary intake.[7] The heart, skeletal muscle, liver and kidneys have special transportation systems for carnitine uptake, resulting in higher concentration of this substance in these organs.[7]
Depletion in carnitine concentration within cells mainly results in diminished ATP production; the main fuel for the living cells.[9] Furthermore, carnitine is involved in numerous physiological processes, including liver ketogenesis,[10] oxidation of branched chain amino acids,[11] β-oxidation in perioxisomes[12] and balancing acyl-CoA/CoA. Accumulation of acyl-CoA has potential toxic effects on the cells; therefore, carnitine plays a protective role through modulating the amount of acyl-CoA within the cells.[13]
Some studies prove that carnitine compounds have free radical scavenger activities. They rescue the cells from apoptosis through protection on mitochondria by acting against the reactive oxygen species.[14]
Carnitine supplementation has been offered in various diseases: primary and secondary carnitine deficiencies,[15,16] diabetes,[17,18] chronic heart failure,[19,20] nonalcoholic steatohepatitis and dyslipidemia,[21,22,23,24] renal failure,[25,26] anemia, leukopenia and thrombocytopenia,[27,28] and drug-induced hepatotoxicity (e.g., valproate, isoniazid and acetaminophen).[29,30,31,32] Numerous studies have investigated the benefits of carnitine supplementation on improving the complications of viral hepatitis, such as steatosis,[33,34,35] fatigue,[36,37,38] uremia and hepatic encephalopathy.[39,40]
Carnitine also reduced some adverse effects related to the standard therapies, including interferon-induced fatigue[41,42] and neutropenia,[43,44] ribavirin-induced anemia[45,46,47] and increased chance of sustained virological response.[17,18,19]
Although there are a few studies evaluating the level of serum carnitine in chronic hepatitis, results are still controversial.[20,36,37,48,49] To the best of our knowledge, there is no study regarding serum carnitine level in individuals with chronic viral hepatitis in the Iranian population. The aim of this study was to evaluate serum carnitine level and its associated factors in this population.
Future Virology. 2014;9(4):373-383. © 2014 Future Medicine Ltd.
