Intrahepatic cholestasis of pregnancy is a pregnancy-specific disease that significantly increases the risk of fetal complications. It is also known as obstetric cholestasis (OC) [13]. It has been reported that inflammation is responsible for hepatocyte damage, dysfunction of biliary transport system, increased toxicity of bile acids and altered apoptosis [14]. Inflammation seems to be a risk factor for etiological pathology of intrahepatic cholestasis of pregnancy. Similarly, inflammation-related hepatic cell degradation products are probably responsible for the injury to the cellular components of the intercellular matrix, which is very important in maternal-fetal interaction. These events may be the reason for obstetrical complications such as prematurity, chronic impaired fetal perfusion and preeclampsia [15]. The pathogenesis of ICP is investigated. ICP laboratory diagnostics is also underway. The lack of agreement on diagnostic criteria contributes to the differences in the management of ICP. A diagnosis of intrahepatic cholestasis of pregnancy is confirmed by an elevated serum level of total bile acids and symptoms including pruritus and jaundice in the late second or third trimester of pregnancy without any sign of chronic liver disease. Elevated serum total bile acid levels (≥ 10 µmol/l) and increased serum aminotransferases with pruritus are the characteristic findings of this pregnancy-specific disease. Bile acids are a large family of molecules that have a steroidal structure and are synthesized from cholesterol in the liver and actively secreted along into the bile. Bile acid levels are increased in the serum and liver in patients with cholestasis and, perhaps because of their detergent action, they may damage hepatocytes. Thus, increased bile acid levels in hepatocytes may account for some of the liver damage in cholestatic liver diseases [16]. If TBA values are higher than 40 micromoles/L, there is an increased risk of fetal complications, although there seems to be no correlation between the severity of maternal symptoms and the level of the total bile acids [17]. No typical diagnostic biomarker, other than the TBA, is currently available. However, serum TBA could not be used to distinguish the ICP patients with low pruritus from normal pregnant women, and even more, normal serum TBA concentrations have been observed in some cases with ICP [18–19]. New diagnostic and prognostic ICP biomarkers are also urgently required. A new group of potential markers are sphingolipids–structural components of cell membranes. These molecules participate in regulation gene expression as well as cell signaling on such phenomena as cell growth and death. They are regulators of hepatic homeostasis, modulators of liver regeneration and markers of liver injury [20] Mikucka et al. reported that sphingolipids can potentially become screening markers as well as markers for monitoring the treatment of ICP in pregnant women. However, their study do not suggest the use of sphingolipids can substitute TBA as earlier or better markers of ICP [21]. In preliminary studies Zou et al. indicated the usefulness of microRNA as ICP biomarkers [22]. MicroRNAs (miRNAs) are small, single-stranded non-coding RNAs (18–24 nt in length) which affect various biological processes including cell proliferation, metabolism, and tissue patterning during development [23]. The expression levels of three miRNAs (miR-371a- 5p, miR-6865-5p, and miR-1182) were significantly increased in ICP patients and may serve as noninvasive biomarkers of ICP [22].
The ADH profile of ICP patients has not previously been investigated. In present study, we found that the total ADH activity changed in the serum in the course of ICP. The cause for the increase of total alcohol dehydrogenase is an elevation of class I ADH. We showed an increase of ADH I (about 60%) activity in the sera of women with intrahepatic cholestasis of pregnancy. In our study we found that baseline serum total bile acids concentration (one of the major markers of ICP) increased in women with ICP. Additionally, TBA was positively correlated with ADH I and ADH activity. In the our study, we also demonstrated that the serum ADH isoenzyme activity during ICP was similar to the activity of aminotransferases (2-times elevation for alanine and 1,5-times for aspartate aminotransferase). The total ADH and class I isoenzyme activities did not correlate with alkaline phosphatase and γ-glutamyltransferase, which are typical enzymatic markers of cholestasis. It is commonly accepted that ALP and γ-GT are membrane bound enzymes and their increase in the sera of patients indicates dysfunction of hepatocyte membranes and enzyme synthesis in parenchymal cells in the course of cholestasis. The rise of aminotransferases always indicates liver cell injury. In the present study, the ADH activity did not correlate with membrane-bound enzymes but was strongly correlated with cytosolic enzymes (aminotransferases).