The biochemical functions of the renal tubules and glomeruli in the course of intrahepatic cholestasis in pregnancy

Proteinuria is a clinical characteristic of intrahepatic cholestasis of pregnancy but it is not a marker of severity: A retrospective cohort study

OBJECTIVES

To determine the prevalence of proteinuria in patients diagnosed with intrahepatic cholestasis of pregnancy (IHCP), and the association between the presence of proteinuria and adverse pregnancy outcomes.

METHODS

This was a retrospective cohort study. The study included all pregnant patients between July 2014 and January 2022, at gestational age > 24weeks who had been diagnosed with IHCP and had completed a 24-hour protein collection. High order multifetal gestations were excluded. Patients were divided into 3 groups:1. IHCP without proteinuria (Non-proteinuric group);2. IHCP with proteinuria and normal blood pressure (Isolated proteinuria group), and 3. IHCP with proteinuria and elevated blood pressure (IHCP with preeclampsia (PET)). Primary outcome was defined as a composite maternal-fetal outcome including: preterm labor <34 weeks, arterial cord blood ph<7.1, rate of Cesarean delivery due to non-reassuring fetal monitoring. Parametric and non-parametric statistical methods were used for analysis.

RESULTS

A total of 272 met all inclusion criteria and were included, 94 patients (34.5%) had proteinuria; of them, 67 (24.6%) had isolated proteinuria and 27 (9.9%) had PET. Demographic parameters were comparable among the groups. Patients with PET had higher rates of in-vitro fertilization (IVF) treatments, twin gestation and elevated serum creatinine and urea levels. The rate of composite adverse pregnancy outcome was higher in patients with PET compared with patients with and without proteinuria (14/27 (51.9%) vs. 18/67 (26.9%) vs. 49/178 (27.5%), respectively, p = 0.03).

CONCLUSIONS

Approximately 35% of patients with IHCP have proteinuria. The presence of PET, rather than isolated proteinuria, is associated with adverse pregnancy outcome.

Establishment of trimester-specific reference intervals of renal function tests and their predictive values in pregnant complications and perinatal outcomes: A population-based cohort study

Objectives

In this study, we aimed to establish the trimester-specific RIs of renal function tests (RFTs) in singleton pregnant women and investigate the associations between adverse perinatal outcomes and abnormal renal function laboratory results.

Methods

The results of RFTs and the associated medical records were retrieved from 16489 singleton pregnant women who underwent first- and third-trimester prenatal screening and gave a live birth at out institute between August 2018 and December 2019. The RFTs were performed on the automated immunochemistry platform ARCHITECT ci16200 (Abbott Laboratories Ltd, Abbott Park, Illinois, US) in the clinical laboratory of our institute. The nonparametric 2.5th-97.5th percentile intervals and the indirect Hoffmann methods were used to define the trimester-specific RIs. The associations between abnormal RFTs and adverse pregnancy outcomes was assessed statistically by logistic regression.

Results

There was no significant difference between the direct observational and the indirect Hoffmann methods in establishing RIs of RFTs. Compared with RFTs in the first trimester, the concentrations of serum BUN and Crea were slightly decreased (p < 0.001), and the serum UA and Cys C levels were significantly elevated in the third trimester (p < 0.001). In the logistic regression analysis, high concentrations of UA, Crea, and Cys C in late pregnancy were associated with an increased risk of postpartum hemorrhage. Meanwhile, early pregnancy UA was associated with a modestly increased risk of GDM, GH, and PE.

Conclusion

It is necessary to establish trimester-specific RIs for RFTs, in order to appropriately interpret laboratory results and to identify women with high risks of developing various adverse outcomes.

Allopurinol Protects Against Cholestatic Liver Injury in Mice Not Through Depletion of Uric Acid

Cholestasis is one of the most severe manifestations of liver injury and has limited therapeutic options. Allopurinol (AP), an inhibitor of uric acid (UA) synthesis, was reported to prevent liver damage in several liver diseases. However, whether AP protects against intrahepatic cholestatic liver injury and what is the role of UA in the pathogenesis of cholestasis remain unknown. In this study, we reported that AP attenuated liver injury in a mouse model of intrahepatic cholestasis induced by alpha-naphthylisothiocyanate (ANIT). AP showed no significant effect on glutathione depletion, inflammation, or bile acid metabolism in livers of ANIT-treated mice. Instead, AP significantly improved fatty acid β-oxidation in livers of ANIT-treated mice, which was associated with activation of PPARα. The protective effect of AP on cholestatic liver injury was not attributable to the depletion of UA, because both exogenous and endogenous UA prevented liver injury in ANIT-treated mice via inhibition of NF-kB-mediated inflammation. In conclusion, the present study provides a new perspective for the therapeutic use of AP and the role of UA in cholestatic liver injury.

Association between intrahepatic cholestasis of pregnancy and risk of gestational diabetes and preeclampsia: a systematic review and meta-analysis

OBJECTIVE

To investigate the association between intrahepatic cholestasis of pregnancy (ICP) and the risk of gestational diabetes mellitus (GDM) and preeclampsia via meta-analysis.

METHODS

Pooled odds ratio (OR) and confidence interval (CI) of GDM and preeclampsia for women with ICP were calculated using the fixed- or random-effects model.

RESULTS

Women with ICP were more likely to have GDM (pooled OR = 2.19, 95% CI: 1.58, 3.03, I ² = 88.25%) and preeclampsia (pooled OR = 2.58, 95% CI: 2.37, 2.81, I ² = 0%) than women without ICP.

CONCLUSION

The present study supports the concept that ICP is associated with the risk of GDM and preeclampsia.

Intrahepatic Cholestasis of Pregnancy in Women With Twin Pregnancy

The aim of the present work was to determine maternal and fetal outcomes of intrahepatic cholestasis of pregnancy (ICP) in twin pregnancies. All twin pregnancies delivered above 28 gestational weeks in West China Second University Hospital from January 2013 to May 2015 were included. Data on maternal demographics and obstetric complications together with fetal outcomes were collected. The risk of adverse maternal and fetal outcomes were determined in relation to ICP by crude odds ratios (OR) and adjusted ORs (aOR) with 95% confidence intervals (CI). Subgroup analysis concentrated on the effect of assisted reproductive technology (ART), ICP severity, and onset time. A total of 1,472 twin pregnancies were included, of which 362 were cholestasis patients and 677 were conceived by ART. Higher rates of preeclampsia (aOR 1.96; 95% CI 1.35, 2.85), meconium-stained amniotic fluid (aOR 3.10; 95% CI 2.10, 4.61), and preterm deliveries (aOR 3.20; 95% CI 2.35, 4.37) were observed in ICP patients. Subgroup analysis revealed higher incidences of adverse outcomes in severe and early onset ICP groups. In conclusion, adverse maternal and fetal outcomes were strongly associated with ICP in twin patients. Active management and close antenatal monitoring are needed, especially in the early onset and severe groups.

Severe intrahepatic cholestasis of pregnancy is a risk factor for preeclampsia in singleton and twin pregnancies

OBJECTIVE

Intrahepatic cholestasis of pregnancy (ICP) is known to be associated with fetal complications. It recently was suggested to be associated possibly with preeclampsia (PET) as well. The objective of this study was to investigate that possibility.

STUDY DESIGN

The study group included 78 women (54 singleton and 24 twin pregnancies) who had been diagnosed with ICP based on clinical presentation, elevated liver enzymes, and elevated total bile acids (>10 μmol/L). Disease severity was based on total bile acids levels as being severe (>40 μmol/L), moderate (20-40 μmol/L), or mild (10-20 μmol/L). The course of disease was reviewed carefully in each case. The control groups were comprised of apparently healthy women with singleton (n = 200) and twin (n = 100) pregnancies that were drawn randomly from a computerized registry of all the deliveries in our institution during the study period.

RESULTS

The total incidence of PET was significantly higher for the patients with ICP who had singleton and twin pregnancies compared with the control groups (singletons: 7.4% vs 1.5%; P < .05; twins: 33.3% vs 6.2%; P < .05, respectively). The incidence of severe PET was also significantly higher in both singleton (11-fold) and twin (8-fold) pregnancies compared with control subjects. Severe ICP, but not mild ICP, was a major risk factor for PET among women with either singleton or twin pregnancies. The timing of the initial presentation of ICP had no effect on PET incidence rates. Preeclampsia occurred usually 2-4 weeks after the diagnosis of ICP, and proteinuria preceded elevated blood pressure in all cases. Moreover, the total bile acid levels among 33 women who were diagnosed as having PET, but not ICP, were within normal range.

CONCLUSION

ICP increases the incidence of PET; severe disease was a major risk factor for preeclampsia. Therefore, we strongly suggest including routine evaluation for preeclampsia in the treatment of women with moderate and severe ICP.

Elevated plasma levels of hypermethylated RASSF1A gene sequences in pregnant women with intrahepatic cholestasis

Intrahepatic cholestasis of pregnancy (ICP) is associated with increased perinatal mortality and morbidity. Circulating cell-free fetal DNA has been a useful parameter for monitoring of pregnancy-associated diseases. The purpose of this study was to determine the concentrations of hypermethylated RAS-association domain family 1, isoform A (RASSF1A) gene sequences in the plasma of pregnant women with intrahepatic cholestasis. This study included 56 women in their third trimester of pregnancy, of whom 26 had ICP (study group) and 30 were healthy (control group). Real time PCR was performed to detect RASSF1A concentrations after methylation-sensitive restriction digestion with HinpII and HhaI to measure cell-free fetal DNA. Beta-actin was detected as an internal control to confirm complete enzyme digestion. The data show a significant increase in the circulating hypermethylated RASSF1A levels regarding the pregnancies complicated with ICP as compared with normal pregnancies. Circulating hypermethylated RASSF1A levels in maternal plasma related to total bile acid. Based on these observations, we suggest that the circulating hypermethylated RASSF1A levels in maternal plasma may be used as a diagnostic marker for ICP.

Pregnancy-Associated Kidney Injury

A 23-year-old G1P0000 without prior past medical history is 31 weeks pregnant with prenatal care presents with complaints of worsening leg and face swelling for the past 2 days now seeks care because of headache, diarrhea, nausea, and vomiting. On exam she is found to have a blood pressure of 120/86, edema, and brisk deep tendon reflexes. Laboratory testing revealed hemoglobin 11.3 g/dl, platelet count 141,000/μl white blood count 18,000/μl, creatinine 1.1 mg/dl, aspartate aminotransferases (AST) 65 U/l, lactate dehydrogenase (LDH) 400 U/l, total bilirubin 1.1 mg/dl, prothrombin time (PT) 14.7 s, ammonia of 90 mcg/dl, blood glucose 139 mg/dl, calcium 7.3 mg/dl, and uric acid of 6.0 mg/dl. The urinalysis demonstrated WBC’s 3–5/hpf, RBC’s 3–5/hpf—non-dysmorphic, renal tubular epithelial cells were seen and a urine protein to creatinine ratio of 2. One day after hospitalization the patient’s blood pressure was 145/87 with a similar blood pressure 6 h later.

Successful perinatal outcome in an early onset intrahepatic cholestasis of pregnancy with extremely high serum hepatic function tests

We report a case of a 21-year-old pregnant woman with an early onset of intrahepatic cholestasis of pregnancy with very high aminotransferases activity and bilirubin concentration. Viral and autoimmune hepatitis, and other possible causes of liver function impairment were excluded. Treatment with ursodeoxycholic acid improved biochemical markers. The patient delivered a healthy female neonate by caesarean section. Neonatal and postoperative courses were uneventful.

Intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disorder characterized by maternal pruritus in the third trimester, raised serum bile acids and increased rates of adverse fetal outcomes. The etiology of ICP is complex and not fully understood, but it is likely to result from the cholestatic effects of reproductive hormones and their metabolites in genetically susceptible women. Equally unclear are the mechanisms by which the fetal complications occur. This article reviews the epidemiology, clinical features, diagnosis, etiology and management of ICP.

Bile-acid-induced cell injury and protection

Several studies have characterized the cellular and molecular mechanisms of hepatocyte injury caused by the retention of hydrophobic bile acids (BAs) in cholestatic diseases. BAs may disrupt cell membranes through their detergent action on lipid components and can promote the generation of reactive oxygen species that, in turn, oxidatively modify lipids, proteins, and nucleic acids, and eventually cause hepatocyte necrosis and apoptosis. Several pathways are involved in triggering hepatocyte apoptosis. Toxic BAs can activate hepatocyte death receptors directly and induce oxidative damage, thereby causing mitochondrial dysfunction, and induce endoplasmic reticulum stress. When these compounds are taken up and accumulate inside biliary cells, they can also cause apoptosis. Regarding extrahepatic tissues, the accumulation of BAs in the systemic circulation may contribute to endothelial injury in the kidney and lungs. In gastrointestinal cells, BAs may behave as cancer promoters through an indirect mechanism involving oxidative stress and DNA damage, as well as acting as selection agents for apoptosis-resistant cells. The accumulation of BAs may have also deleterious effects on placental and fetal cells. However, other BAs, such as ursodeoxycholic acid, have been shown to modulate BA-induced injury in hepatocytes. The major beneficial effects of treatment with ursodeoxycholic acid are protection against cytotoxicity due to more toxic BAs; the stimulation of hepatobiliary secretion; antioxidant activity, due in part to an enhancement in glutathione levels; and the inhibition of liver cell apoptosis. Other natural BAs or their derivatives, such as cholyl-N-methylglycine or cholylsarcosine, have also aroused pharmacological interest owing to their protective properties.

Alpha-hydroxybutyrate dehydrogenase activity in intrahepatic cholestasis of pregnancy

OBJECTIVES

Intrahepatic cholestasis of pregnancy (ICP) is associated with increased perinatal mortality and morbidity. Alpha-hydroxybutyrate dehydrogenase (alpha-HBDH) is an enzyme that originates in the cytoplasm of hepatocytes and can be detected in the serum. The aim of this study was to determine the characteristics of alpha-HBDH activity in ICP.

METHODS

The study included 100 women in their third trimester of pregnancy, 58 of whom had ICP (the study group) and 42 were healthy (the control group); another group, 26 nonpregnant women, was also analyzed to follow changes in alpha-HBDH activity during pregnancy. The concentrations or activity of fractionated bilirubin; bile acids; total alkaline phosphatase; alanine and aspartate aminotransferases; total high-density and low-density lipoprotein cholesterol; triglycerides; total protein; and alpha-HBDH were assessed.

RESULTS

The activity of serum alpha-HBDH is increased during the third trimester of pregnancies complicated by ICP, and it correlates positively with total and direct bilirubin concentration and total alkaline phosphatase activity.

CONCLUSIONS

Alpha-hydroxybutyrate dehydrogenase serum activity seems to be another biochemical parameter useful in the assessment of ICP severity.

Extremely elevated activity of serum alkaline phosphatase in gestational diabetes: a case report

We report a case of a 25-year-old pregnant woman with gestational diabetes and increased activity (25-fold) of placental isozyme of alkaline phosphatase. Abdominal ultrasonographic scan revealed no hepatobiliary disease. After delivery, the alkaline phosphatase level decreased but did not return to the reference range. Similar abnormalities were found in the patient's first-degree relatives, which included a mother and a sister.