Liver disease in pregnancy and fetal fatty acid oxidation defects

Annonaceous acetogenins mimic AA005 targets mitochondrial trifunctional enzyme alpha subunit to treat obesity in male mice

Obesity and related diseases pose a major health risk, yet current anti-obesity drugs inadequately addressing clinical needs. Here we show AA005, an annonaceous acetogenin mimic, resists obesity induced by high-fat diets and leptin mutations at non-toxic doses, with the alpha subunit of the mitochondrial trifunctional protein (HADHA) as a target identified through proteomics and in vitro validation. Pharmacokinetic analysis shows AA005 enriches in adipose tissue, prompting the creation of adipose-specific Hadha-deficient mice. These mice significantly mitigate diet-induced obesity, echoing AA005's anti-obesity effects. AA005 treatment and Hadha deletion in adipose tissues increase body temperature and energy expenditure in high-fat diet-fed mice. The beneficial impact of AA005 on obesity mitigation is ineffective without uncoupling protein 1 (UCP1), essential for thermogenesis regulation. Our investigation shows the interaction between AA005 and HADHA in mitochondria, activating the UCP1-mediated thermogenic pathway. This substantiates AA005 as a promising compound for obesity treatment, targeting HADHA specifically.

Genetic aetiologies of acute liver failure

Acute liver failure (ALF) is a rare, rapidly evolving, clinical syndrome with devastating consequences where definitive treatment is by emergency liver transplantation. Establishing a diagnosis can be challenging and, historically, the cause of ALF was unidentified in up to half of children. However, recent technological and clinical advances in genomic medicine have led to an increasing proportion being diagnosed with monogenic aetiologies of ALF. The conditions encountered include a diverse group of inherited metabolic disorders each with prognostic and treatment implications. Often these disorders are clinically indistinguishable and may even mimic disorders of immune regulation or red cell disorders. Rapid genomic sequencing for children with ALF is, therefore, a key component in the diagnostic work up today. This review focuses on the monogenic aetiologies of ALF.

A prediction model for the progression from gestational hypertension to pre-eclampsia complicated with HELLP syndrome

OBJECTIVE

HELLP syndrome is a severe complication of hypertensive disorders of pregnancy that can cause multiple organ dysfunction and maternal death in a short period of time. Although HELLP syndrome is more common in patients with pre-eclampsia (PE), there is currently no effective way to identify high-risk individuals who may progress from gestational hypertension (GH) to PE complicated with HELLP syndrome. This study aimed to establish and validate a prediction model for PE complicated with HELLP syndrome, providing a basis for early detection and identification of high-risk individuals in clinical practice.

METHODS

This retrospective case-control study collected data on 326 patients with GH and 139 patients with PE complicated with HELLP syndrome from January 2015 to December 2019. An additional 206 patients with GH and 70 patients with PE complicated with HELLP syndrome who were treated from January 2020 to December 2022 were collected for external validation. General and clinical data were collected, and single-and multiple-factor logistic regression analyses were used to screen for independent factors affecting PE complicated with HELLP syndrome. The diagnostic performance of different indicators was evaluated using ROC curves. A prediction model for PE complicated with HELLP syndrome was constructed, and its efficacy was verified using ROC curves.

RESULTS

The results of single-factor analysis showed that age, SBP, DBP, MAP, hemoglobin, AST, ALT, cholinesterase, alkaline phosphatase, gamma-glutamyl transferase, total protein, total bilirubin, direct bilirubin, indirect bilirubin, BUN, UA, creatinine, APTT, international normalized ratio of prothrombin, D-dimer, fibrinogen, fibrinogen degradation products, Ca, and aspartate-aminotransferase to platelet ratio index (APRI) were factors influencing PE with HELLP syndrome. The results of multiple-factor logistic regression analysis showed that MAP, APRI, CHE, FDP, and Ca were independent factors affecting PE complicated with HELLP syndrome. Based on these results, a prediction model was established, with Y = 9.861 + 2.998APRI + 0.055MAP + 0.014FDP - 0.005CHE - 7.452*Ca.

CONCLUSIONS

The predictive model for PE complicated with HELLP syndrome includes APRI, MAP, FDP, CHE, and Ca. This model can be used as a quantitative tool for predicting and evaluating the development of GH into PE complicated with HELLP syndrome.

Characterization of pregnancy outcome of women with an offspring with inborn errors of metabolism: A population-based study

Introduction: Inborn errors of metabolism (IEM) are scarce, and their diagnosis is often made after birth. This has led to the perception that most fetuses affected by these disorders do not become clinically apparent during pregnancy. Our aim was to determine the obstetrical characteristics of women with an offspring affected by IEM.

Methods: This population-based retrospective cohort study included all women who delivered at the Soroka University Medical Center (SUMC) from 1988 to 2017 who met the inclusion criteria. Mothers who had an offspring with IEM were included in the study group, and those who had offsprings without IEM comprised the comparison group.

Results: A total of 388,813 pregnancies were included in the study, and 184 of them were complicated by a fetus with IEM. The number of Bedouin women was higher in the IEM-affected infant group than in the comparison group (90.8% vs. 53.3%, p < 0.001); women who had a fetus with IEM had a higher rate of polyhydramnios (7.1% vs. 3.2%, p = 0.005), HELLP syndrome (3.3% vs. 1.1%, p = 0.014), and preterm birth (20.7% vs. 10.1%, p < 0.001); neonates with IEM had lower mean birth weight (p < 0.001), lower Apgar scores at 1′ and 5′ minutes (p < 0.001), and a higher rate of fetal growth restriction (FGR) (p < 0.001), postpartum death <28 days (p < 0.001), and neonatal death (p < 0.001) than those in the comparison group. Pregnancies with IEM fetuses were independently associated with preterm birth (OR 2.00; CI 1.4–3), polyhydramnios (OR 2.08; CI 1.17–3.71), and FGR (OR 2.24; CI 1.2–4.19). Each family of metabolic diseases is independently associated with specific pregnancy complications (i.e., mitochondrial diseases are associated with HELLP syndrome (OR 5.6; CI 1.8–17), and lysosomal storage disease are associated with nonimmune hydrops fetalis (OR 26.4; CI 3.39–206).

Conclusion: This study reports for the first time, an independent association of IEM with specific complications of pregnancy. This observation has clinical implications, as the identification of specific pregnancy complications in a population at risk for IEM can assist in the prenatal diagnosis of an affected fetus.

Kidney-Placenta Crosstalk in health and disease

Organ crosstalk allows the interaction between systems to adapt to a constant changing environment, maintaining homeostasis. The process of placentation and the new hormonal environment during pregnancy trigger physiological changes that modulate kidney function to control extracellular volume, acid-base balance, and filtration of metabolic waste products. The bidirectional communication means that acute or chronic dysfunction of one organ can compromise the other. Abnormal placentation in pregnancy-related hypertensive disorders such as pre-eclampsia and HELLP (haemolysis, elevated liver enzymes and low platelet count) syndrome leads to the release of antiangiogenic factors that may cause kidney injury (thrombotic microangiopathy, glomeruloendotheliosis, mesangiolysis and vasoconstriction of peritubular vessels). These hypertensive disorders are a key cause of kidney injury in gestation, which increases maternal morbi-mortality and adverse foetal outcomes. Conversely, prior kidney injury or causes of kidney injury (diabetes, lupus, glomerulonephritis or other form of chronic kidney disease) increase the risk of developing hypertensive pregnancy disorders, providing a baseline higher risk. Inherited kidney diseases are a special concern, given the potential for genetic predisposition to kidney disease in the foetus. Understanding the bidirectional potential for compromise from placenta to kidney and vice versa provides a better framework to limit damage to both organs and improve maternal and foetal outcomes.

Laboratory analysis of acylcarnitines, 2020 update: a technical standard of the American College of Medical Genetics and Genomics (ACMG)

Acylcarnitine analysis is a useful test for identifying patients with inborn errors of mitochondrial fatty acid β-oxidation and certain organic acidemias. Plasma is routinely used in the diagnostic workup of symptomatic patients. Urine analysis of targeted acylcarnitine species may be helpful in the diagnosis of glutaric acidemia type I and other disorders in which polar acylcarnitine species accumulate. For newborn screening applications, dried blood spot acylcarnitine analysis can be performed as a multiplex assay with other analytes, including amino acids, succinylacetone, guanidinoacetate, creatine, and lysophosphatidylcholines. Tandem mass spectrometric methodology, established more than 30 years ago, remains a valid approach for acylcarnitine analysis. The method involves flow-injection analysis of esterified or underivatized acylcarnitines species and detection using a precursor-ion scan. Alternative methods utilize liquid chromatographic separation of isomeric and isobaric species and/or detection by selected reaction monitoring. These technical standards were developed as a resource for diagnostic laboratory practices in acylcarnitine analysis, interpretation, and reporting.

Crystal structure of human mitochondrial trifunctional protein, a fatty acid β-oxidation metabolon

Membrane-bound mitochondrial trifunctional protein (TFP) catalyzes β-oxidation of long chain fatty acyl-CoAs, employing 2-enoyl-CoA hydratase (ECH), 3-hydroxyl-CoA dehydrogenase (HAD), and 3-ketothiolase (KT) activities consecutively. Inherited deficiency of TFP is a recessive genetic disease, manifesting in hypoketotic hypoglycemia, cardiomyopathy, and sudden death. We have determined the crystal structure of human TFP at 3.6-Å resolution. The biological unit of the protein is α₂β₂ The overall structure of the heterotetramer is the same as that observed by cryo-EM methods. The two β-subunits make a tightly bound homodimer at the center, and two α-subunits are bound to each side of the β₂ dimer, creating an arc, which binds on its concave side to the mitochondrial innermembrane. The catalytic residues in all three active sites are arranged similarly to those of the corresponding, soluble monofunctional enzymes. A structure-based, substrate channeling pathway from the ECH active site to the HAD and KT sites is proposed. The passage from the ECH site to the HAD site is similar to those found in the two bacterial TFPs. However, the passage from the HAD site to the KT site is unique in that the acyl-CoA intermediate can be transferred between the two sites by passing along the mitochondrial inner membrane using the hydrophobic nature of the acyl chain. The 3'-AMP-PPi moiety is guided by the positively charged residues located along the "ceiling" of the channel, suggesting that membrane integrity is an essential part of the channel and is required for the activity of the enzyme.

Role of 3-Hydroxy Fatty Acid-Induced Hepatic Lipotoxicity in Acute Fatty Liver of Pregnancy

Acute fatty liver of pregnancy (AFLP), a catastrophic illness for both the mother and the unborn offspring, develops in the last trimester of pregnancy with significant maternal and perinatal mortality. AFLP is also recognized as an obstetric and medical emergency. Maternal AFLP is highly associated with a fetal homozygous mutation (1528G>C) in the gene that encodes for mitochondrial long-chain hydroxy acyl-CoA dehydrogenase (LCHAD). The mutation in LCHAD results in the accumulation of 3-hydroxy fatty acids, such as 3-hydroxy myristic acid, 3-hydroxy palmitic acid and 3-hydroxy dicarboxylic acid in the placenta, which are then shunted to the maternal circulation leading to the development of acute liver injury observed in patients with AFLP. In this review, we will discuss the mechanistic role of increased 3-hydroxy fatty acid in causing lipotoxicity to the liver and in inducing oxidative stress, mitochondrial dysfunction and hepatocyte lipoapoptosis. Further, we also review the role of 3-hydroxy fatty acids in causing placental damage, pancreatic islet β-cell glucolipotoxicity, brain damage, and retinal epithelial cells lipoapoptosis in patients with LCHAD deficiency.

[Acute fatty liver of pregnancy and mitochondrial fatty acid oxidation. Consequences for the offspring]

Acute fatty liver of pregnancy (AFLP) is a rare liver disease unique to pregnancy that can lead to acute liver failure. The prognosis, initially often fatal for both mother and child, has been improved by prompt delivery. The diagnosis should be highly suspected if the mother presents epigastric pain, nausea and/or vomiting, or polyuria-polydipsia in the third trimester of pregnancy. AFLP has been found associated with a genetic deficiency of fatty acid beta-oxidation, which may cause sudden death in infancy. Consequently, the mother and her newborn should undergo screening for this deficiency.

Acute Fatty Liver Disease of Pregnancy: Updates in Pathogenesis, Diagnosis, and Management

Acute fatty liver of pregnancy (AFLP) is an obstetric emergency characterized by maternal liver failure and may have complications for the mother and fetus, including death. This review examines recent literature on the epidemiology, pathogenesis, diagnosis, and treatment of acute fatty liver of pregnancy. Pathogenesis of this disease has been linked to defects in fatty acid metabolism during pregnancy, especially in the setting of fetal genetic defects in fatty acid oxidation. The value of screening all patients for these genetic defects remains to be determined. Distinguishing AFLP from other high-risk liver diseases of pregnancy that have overlap features, such as HELLP and preeclampsia, can be challenging. Although sensitive diagnostic tools such as the Swansea criteria have been developed, further work is needed to diagnose AFLP more quickly. Although survival rates have improved in the past 30 years, delay in diagnosis and treatment of AFLP has life-threatening consequences; an algorithmic approach to AFLP may be a valuable resource for clinicians. Future epidemiological and long-term studies will improve our prediction of women at risk for developing AFLP and determine the long-term consequences of this condition.

Obstetric care in women with genetic disorders

The management of pregnant women who are themselves affected with genetic diseases is an increasingly relevant and important issue. Improvements in early diagnosis and management of genetic disease, as well as advances in assisted reproductive technology have impacted pregnancy rates in a cohort of women who may not have otherwise been able to conceive. A multidisciplinary approach is key to the management of pregnant women with complex health conditions, including genetic diseases. Pertinent issues should be addressed in the preconception, antepartum, intrapartum and postpartum periods to optimize maternal and fetal health. Additionally, counseling regarding risk of inheritance in offspring and options for prenatal diagnosis should be reviewed if available. This reviews aims to help provide background and insight into the management strategies for various commonly encountered and complex genetic conditions in the setting of pregnancy.

Strategies for the prevention of mother to child transmission in Western countries: an update

BACKGROUND

During the last decades remarkable scientific advances have been made toward the prevention of HIV mother-to-child transmission, in particular in developed nations. The aim of this review was to analyze the latest findings and available international recommendations on the prevention of HIV mother-to-child transmission in high-income countries.

METHODS

We performed a literature search of the Cochrane Library, MEDLINE by PubMed and EMBASE from database inception through June 2014, using the following terms: HIV, mother-to-child transmission and mother-to-child-transmission prevention. All types of articles in the English language were included. US and available European guidelines were searched and included in the analysis.

RESULTS

One hundred fifty articles were selected for inclusion in this review.

CONCLUSIONS

Global epidemiology of HIV infection is rapidly evolving, in particular in high-resource countries. The interpretation of clinical and epidemiological studies is crucial for the development of evidence-based recommendations to guide the management of HIV mother-to-child transmission. Although significant progress has been made, heterogeneity between countries in specific interventions still exists, which may address future research.

HELLP syndrome preceded by intrahepatic cholestasis of pregnancy: one serious itch

We present four women with seven ongoing pregnancies. Five pregnancies were complicated by intrahepatic cholestasis of pregnancy (ICP) and severe haemolysis, elevated liver enzymes and low platelets (HELLP) syndrome with uncommon maternal morbidity. The combination of ICP and HELLP syndrome has not previously been reported. Awareness is warranted to accurately identify this combination of pregnancy-specific diseases with severe maternal morbidity.

Liver diseases in pregnancy: Diseases unique to pregnancy

Pregnancy is a special clinical state with several normal physiological changes that influence body organs including the liver. Liver disease can cause significant morbidity and mortality in both pregnant women and their infants. This review summarizes liver diseases that are unique to pregnancy. We discuss clinical conditions that are seen only in pregnant women and involve the liver; from Hyperemesis Gravidarum that happens in 1 out of 200 pregnancies and Intrahepatic Cholestasis of Pregnancy (0.5%-1.5% prevalence), to the more frequent condition of preeclampsia (10% prevalence) and its severe form; hemolysis, elevated liver enzymes, and a low platelet count syndrome (12% of pregnancies with preeclampsia), to the rare entity of Acute Fatty Liver of Pregnancy (incidence of 1 per 7270 to 13000 deliveries). Although pathogeneses behind the development of these aliments are not fully understood, theories have been proposed. Some propose the special physiological changes that accompany pregnancy as a precipitant. Others suggest a constellation of factors including both the mother and her fetus that come together to trigger those unique conditions. Reaching a timely and accurate diagnosis of such conditions can be challenging. The timing of the condition in relation toward which trimester it starts at is a key. Accurate diagnosis can be made using specific clinical findings and blood tests. Some entities have well-defined criteria that help not only in making the diagnosis, but also in classifying the disease according to its severity. Management of these conditions range from simple medical remedies to measures such as immediate termination of the pregnancy. In specific conditions, it is prudent to have expert obstetric and medical specialists teaming up to help improve the outcomes.

Pathophysiology of fatty acid oxidation disorders and resultant phenotypic variability

Fatty acids are a major fuel for the body and fatty acid oxidation is particularly important during fasting, sustained aerobic exercise and stress. The myocardium and resting skeletal muscle utilise long-chain fatty acids as a major source of energy. Inherited disorders affecting fatty acid oxidation seriously compromise the function of muscle and other highly energy-dependent tissues such as brain, nerve, heart, kidney and liver. Such defects encompass a wide spectrum of clinical disease, presenting in the neonatal period or infancy with recurrent hypoketotic hypoglycaemic encephalopathy, liver dysfunction, hyperammonaemia and often cardiac dysfunction. In older children, adolescence or adults there is often exercise intolerance with episodic myalgia or rhabdomyolysis in association with prolonged aerobic exercise or other exacerbating factors. Some disorders are particularly associated with toxic metabolites that may contribute to encephalopathy, polyneuropathy, axonopathy and pigmentary retinopathy. The phenotypic diversity encountered in defects of fat oxidation is partly explained by genotype/phenotype correlation and certain identifiable environmental factors but there remain many unresolved questions regarding the complex interaction of genetic, epigenetic and environmental influences that dictate phenotypic expression. It is becoming increasingly clear that the view that most inherited disorders are purely monogenic diseases is a naive concept. In the future our approach to understanding the phenotypic diversity and management of patients will be more realistically achieved from a polygenic perspective.

Genetics and metabolic cardiomyopathies

Metabolic disorders encompass a heterogeneous group of conditions that commonly affect the heart and contribute adversely to cardiovascular outcomes. As the heart is a metabolically active organ, inborn errors in metabolism (IEMs) often present with cardiac manifestations such as cardiomyopathy, arrhythmia, and valvular dysfunction. More than 40 IEMs are reported to cause cardiomyopathy, including fatty acid oxidation defects, glycogen, lysosomal and perioxisome storage diseases, mitochondrial cardiomyopathies, organic acidaemias, aminoacidopathies and congenital disorders of glycosylation. Studies suggest that IEM account for only 5% of cardiomyopathies; however, their diagnosis is imperative to enable the effective institution of disease-specific management strategies. This review describes the more common genetic defects that affect metabolic pathways and give rise to heart muscle disease.

Metabolic and mitochondrial effects of antiretroviral drug exposure in pregnancy and postpartum: implications for fetal and future health

Antiretroviral drugs (ARVs) are indispensable in the treatment and prevention of human immunodeficiency virus infection. Although their use before, during and after pregnancy is considered safe for mother and child, there are still lingering concerns about their long-term health consequences and the ramifications of their effects on lipid, glucose, intermediary and mitochondrial metabolism. This article reviews the known effects of ARVs on macromolecular and mitochondrial metabolism as well as the potential maternal, fetal, neonatal and adult health risks associated with abnormal energy metabolism during gestation. Recommendations about enhanced monitoring for these risks in affected populations are being provided.

[Acute fatty liver in pregnancy: revealing fetal fatty acid oxidation disorders]

Acute fatty liver of pregnancy (AFLP) and hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome are serious maternal illnesses occurring in the third trimester of pregnancy with significant perinatal and maternal mortality. AFLP may result from mitochondrial defects in the beta-oxidation of fatty acids, in particular a deficiency of the long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) in the fetus. Clinical findings in AFLP vary and its diagnosis is complicated by a significant overlap in clinical and biochemical features with HELLP syndrome. We report the case of 2 siblings who died, the first one in the neonatal period of asphyxia with multivisceral presentation and the second one from sudden death at 7 months. Autopsy of the latter infant revealed hepatic steatosis associated with cardiomyopathy, which led to suspicion of a fatty acid oxidation deficiency. Mutation analysis demonstrated that both children were homozygous for the common mutation c.1528G>C and the parents were heterozygous for this same mutation. This case demonstrates the importance of screening mothers with acute fatty liver disease of pregnancy and their children at birth for a metabolic disease. This article proposes several metabolic tests for mother and child suspected of having beta-oxidation of a fatty acid disorder.

Fatty acid oxidation disorders: outcome and long-term prognosis

Assessing the outcome of fatty acid oxidation disorders is difficult, as most are rare. For diagnosis by newborn screening, the situation is compounded: far more cases are diagnosed by screening than by clinical presentation, representing a somewhat different cohort. The literature on outcome was reviewed. For disorders other than medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) deficiency there was insufficient evidence to make many firm statements. In MCAD deficiency, risk of death in the first 72 h is around 4%, with a further approximately 5-7% fatality rate in the first 6 years but very low subsequent risk in previously undiagnosed patients. The risk of death after diagnosis is very low at any age, with good management. The long-term outcome is good nowadays. Very-long-chain acyl-CoA dehydrogenase deficiency poses a risk of death in early infancy, but the condition is generally treatable, with a good outcome after diagnosis. Approximately 10-20% of patients diagnosed by newborn screening and treated nevertheless suffer episodic rhabdomyolysis. Some patients never become symptomatic. Isolated long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency is treatable, but most patients suffer episodic hypoketotic hypoglycaemia and rhabdomyolysis. Generalised mitochondrial tri-functional protein deficiency has high early mortality rate. A more insidious presentation also occurs, with symptoms sometimes confined to progressive axonal neuropathy. Among carnitine cycle disorders, carnitine transporter deficiency, potentially lethal, is uniformly successfully treated orally with carnitine. Carnitine-acylcarnitine translocase and early-onset carnitine palmitoyl transferase type II (CPT II) deficiencies have an extremely high neonatal mortality rate. Late-onset CPT II is characterised only by episodic rhabdomyolysis on severe exercise. CPT type IA deficiency may often be benign, although early presentation with hypoketotic hypoglycaemia certainly occurs.

Fatty acid oxidation disorders: maternal health and neonatal outcomes

Mitochondrial fatty acid beta-oxidation (FAO) disorders have become an important group of inherited metabolic disorders causing serious pediatric and maternal morbidity and mortality. More than 20 defects affecting beta-oxidation have been discovered, characterized by distinct enzyme or transporter deficiencies. This growing number of FAO disorders covers a wide spectrum of phenotypes and are characterized by a wide array of clinical presentations. We discuss the major mitochondrial FAO disorders and the impact they have on maternal health and neonatal outcomes; diagnostic tools and the value of genetic screening are reviewed; and current therapeutic approaches and management strategies are discussed.

Proteomic analysis of liver tissue from HBx-transgenic mice at early stages of hepatocarcinogenesis

The hepatitis B virus X-protein (HBx), a multifunctional viral regulator, participates in the viral life cycle and in the development of hepatocellular carcinoma (HCC). We previously reported a high incidence of HCC in transgenic mice expressing HBx. In this study, proteomic analysis was performed to identify proteins that may be involved in hepatocarcinogenesis and/or that could be utilized as early detection biomarkers for HCC. Proteins from the liver tissue of HBx-transgenic mice at early stages of carcinogenesis (dysplasia and hepatocellular adenoma) were separated by 2-DE, and quantitative changes were analyzed. A total of 22 spots displaying significant quantitative changes were identified using LC-MS/MS. In particular, several proteins involved in glucose and fatty acid metabolism, such as mitochondrial 3-ketoacyl-CoA thiolase, intestinal fatty acid-binding protein 2 and cytoplasmic malate dehydrogenase, were differentially expressed, implying that significant metabolic alterations occurred during the early stages of hepatocarcinogenesis. The results of this proteomic analysis provide insights into the mechanism of HBx-mediated hepatocarcinogenesis. Additionally, this study identifies possible therapeutic targets for HCC diagnosis and novel drug development for treatment of the disease.

Adult presentations of medium-chain acyl-CoA dehydrogenase deficiency (MCADD)

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is an autosomal recessive disorder of mitochondrial fatty acid oxidation which is usually diagnosed in infancy or through neonatal screening. In the absence of population screening, adults with undiagnosed MCADD can be expected. This review discusses 14 cases that were identified during adulthood. The mortality of infantile patients is approximately 25% whereas in this adult case series it was shown it to be 50% in acutely presenting patients and 29% in total. Therefore, undiagnosed individuals are at risk of sudden fatal metabolic decompensation with high mortality. This review illustrates the need to consider the possibility of a fatty acid oxidation defect in an adult who presents with unexplained sudden clinical deterioration, particularly if precipitated by fasting or alcohol consumption. A history of unexplained sibling death may also raise the index of suspicion. There also needs to be appropriate clinical support for those patients identified clinically or as a result of family studies (sibling or parent).

[Recurrent acute fatty liver of pregnancy]

Acute fatty liver of pregnancy (AFLP) is a rare liver disease unique to pregnancy potentially fatal for both mother and child. Only a few cases of recurrence have been published. We report a new case. A 27-year-old primiparous patient presented a first episode of AFLP in 1991 at 37 week's gestation. Diagnosis was suspected because of vomiting, thrombocytopenia, and liver function tests abnormalities. It was confirmed by liver ultrasonography and abdominal computed tomography. Clinical and biological improvement was observed after caesarean delivery. Six years later, the woman began a second pregnancy. Liver function tests and complete blood count were regularly checked. At 30 weeks' gestation, recurrent AFLP occurred and caesarean section was performed. Again, diagnosis was confirmed by both ultrasonography and abdominal computed tomography. In 2006, the mother and the two girls, 15 and 8-year-old respectively, were in good health. The study of the HADHA gene, coding alpha subunit long chain 3-hydroxyacyl coenzyme A dehydrogenase (LCHAD) in the patient failed to find mutations, particularly the common mutation c.1528G>C (Glu474-Gln, p.E474Q). In conclusion, after an episode of AFLP, women should be clearly warned of the risk of recurrence and regularly monitored during the next pregnancy, even if the search of HADHA gene mutation is negative.

Anesthesia for the pregnant HIV patient

Numbers of HIV-infected individuals across the globe are increasing, as is the proportion of women infected with HIV. However, better understanding of the HIV virus, and rapidly evolving treatments has provided hope for millions of people world-wide. In the pregnant population, recent understanding of factors influencing vertical transmission has enabled dramatic reductions in mother-to-child transmission. The anesthesiologist is likely to encounter HIV-infected parturients in the delivery suite as part of routine practice, and should be aware of the current trends in obstetric -- as well as anesthetic -- best practice and management.

Role of short-chain hydroxyacyl CoA dehydrogenases in SCHAD deficiency

Short-chain hydroxyacyl CoA dehydrogenase deficiency is an ill-defined, severe pediatric disorder of mitochondrial fatty acid beta-oxidation of short-chain hydroxyacyl CoAs. To understand the relative contributions of the two known short-chain hydroxyacyl CoA dehydrogenases (HADH) tissue biopsies of six distinct family individuals were analyzed and kinetic parameters were compared. Steady-state kinetic constants for HADH 1 and HADH 2 suggest that type 1 is the major enzyme involved in mitochondrial beta-oxidation of short-chain hydroxyacyl-CoAs. Two patients are heterozygous carriers of a HADH 1 polymorphism, whereas no mutation is detected in the HADH 2 gene of all patients. The data suggest that protein interactions rather than HADH mutations are responsible for the disease phenotype. Pull-down experiments of recombinant HADH 1 and 2 with human mitochondrial extracts reveal two proteins interacting with HADH 1, one of which was identified as glutamate dehydrogenase. This association provides a possible link between fatty acid metabolism and the hyperinsulinism/hyperammonia syndrome.

Mechanisms of hepatic regeneration following portal vein embolization and partial hepatectomy: a review

BACKGROUND

Portal vein embolization (PVE) improves outcome following major hepatectomy, and basic studies have presented evidence related to the mechanisms responsible for hepatic regeneration. Hemodynamic changes following PVE are similar to, but slightly different from, those of partial hepatectomy (PH) because arterial flow to the embolized lobe is preserved. However, the process of hepatic regeneration is essentially the same after both PVE and PH. A number of mediators are involved in PVE or PH-induced hepatic regeneration. These include inflammatory cytokines, vasoregulators, growth factors, eicosanoids, and various hormones. These mediators activate a complex network of signal transduction that promotes hepatic regeneration. A variety of conditions have been shown to modulate the function of these mediators and inhibit regeneration. These include biliary obstruction, diabetes, chronic ethanol consumption, malnutrition, gender, aging, and infection.

CONCLUSION

Optimizing these factors, where possible, before PVE or PH, is essential to maximize hypertrophy of the liver. A fuller understanding of hepatic physiology and pathophysiology following PVE or PH may lead to greater functional capacity of the remaining liver and extend the indications for hepatectomy in patients who require large liver volume resection.

Neither maternal nor fetal mutation (E474Q) in the alpha-subunit of the trifunctional protein is frequent in pregnancies complicated by HELLP syndrome

OBJECTIVE

An association between maternal HELLP syndrome and fetal long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency has been proposed. LCHAD catalyzes the third step in the beta-oxidation of fatty acids in mitochondria. Whereas about 75% of LCHAD-deficient patients carry a G-to-C mutation at nucleotide position 1528 (Glu474Gln, E474Q) on both chromosomes, compound heterozygosity for E474Q on one chromosome and a second different LCHAD mutation on the other can be observed in up to 25% of LCHAD-deficiency cases; only very few patients carry two mutations different from E474Q. Genetic analysis of the mother alone is insufficient in case of compound heterozygosity. Since information on the fetal carrier status of the E474Q mutation in maternal HELLP syndrome is rare, we investigated the frequency of the E474Q mutation in families where the mother had HELLP syndrome.

METHODS

The occurrence of the E474Q mutation was analyzed by PCR and RFLP in 103 mothers with HELLP syndrome, in 82 children of affected pregnancies and in 21 fathers in families where fetal DNA was not available. In addition, 103 control women with only uncomplicated pregnancies were investigated.

RESULTS

The mutation E474Q was not detected in the study population.

CONCLUSION

Neither maternal nor fetal heterozygosity for the E474Q mutation is a relevant factor of HELLP syndrome.

Mechanism of impaired hepatic regeneration in cholestatic liver

The regenerative capacity of the liver is an important factor following liver surgery. The dramatic change in portal venous flow, due to either portal vein embolization or partial hepatectomy, induces a rapid change in liver volume. In response to these stresses, hepatocytes are primed, through the release of inflammatory cytokines, to increase the expression of immediate early genes and increase the activation of transcriptional factors. The primed hepatocytes then respond to growth factors, including hepatocyte growth factor, epidermal growth factor, and transforming growth factor-alpha. Several pathologic conditions have been shown to inhibit hepatic regeneration. These include diabetes mellitus, malnutrition, aging, infection, chronic ethanol consumption, and biliary obstruction. Impaired hepatic regeneration in the setting of biliary obstruction is an especially serious problem because it can be a major determinant in not considering surgical treatment. The mechanism responsible for impaired hepatic regeneration in patients with biliary obstruction includes decreased portal venous flow, attenuated production of liver proliferation-associated factors, an increased rate of apoptosis, and lack of enterohepatic circulation. Restoring these factors may lead to an improvement in regeneration in a cholestatic liver following portal vein embolization or partial hepatectomy. This review article summarizes the current understanding of the mechanism of hepatic regeneration, with particular emphasis on that in the cholestatic liver.

Heterozygosity for a Mendelian disorder as a risk factor for complex disease

While genetic diseases are generally classified as being either 'simple' monogenic or 'complex' polygenic, the distinction between Mendelian and complex disorders is becoming increasingly blurred. Mendelian disorders may demonstrate qualities more typical of multifactorial diseases through shared clinical presentations, the effect of genetic modifiers, moonlighting proteins, synergistic heterozygosity, disease manifestations in heterozygotes and situations where heterozygosity for a 'simple' disorder proves to be a risk factor for seemingly unrelated complex diseases. A recent example of the last instance is the observation that mutations in glucocerebrosidase, the enzyme deficient in Gaucher disease, may be a risk factor for the development of Parkinson disease and other synucleinopathies. Insights gleaned from the study of Mendelian disorders may ultimately lead to a better understanding of factors influencing complex diseases.

Acute fatty liver of pregnancy

Acute fatty liver of pregnancy (AFLP) is a rare, potentially fatal complication that occurs in the third trimester or early postpartum period. Although the exact pathogenesis is unknown, this disease has been linked to an abnormality in fetal fatty acid metabolism. Early diagnosis of AFLP sometimes can be difficult because it shares features with other common conditions such as pre-eclampsia, viral hepatitis and cholestasis of pregnancy. However, a careful history and physical examination, in conjunction with compatible laboratory and imaging results, are often sufficient to make the diagnosis, and liver biopsy is rarely indicated. Supportive care and expeditious delivery are essential to optimal maternal-fetal outcomes and remain as the mainstay treatment for AFLP.

Gender-specific considerations in the antiretroviral management of HIV-infected women

The vast majority of HIV-infected women are of childbearing potential, so issues surrounding reproduction and mother-to-child transmission of the virus are critical in the management of this population. Optimal antiretroviral management of pregnant women is a major global issue since antiretroviral regimens offered to pregnant women to decrease mother-to-child transmission in many countries are often not highly active against HIV. The subsequent emergence of resistant virus can have long-term sequelae for the mother, child, and ultimately, other exposed individuals. The efficacy of antiretroviral therapy appears similar in men and women, although women may experience higher toxicity profiles, which may, in turn, be related to the higher antiretroviral concentrations shown in pharmacokinetic studies. Further investigation into gender-related issues, including sex-associated antiretroviral toxicities, unique pharmacokinetic profiles and optimal antiretroviral management during pregnancy is needed.

Fetal fatty acid oxidation defects and maternal liver disease in pregnancy

OBJECTIVE

The objective was to evaluate the relationships between all types of fetal fatty acid oxidation defects and maternal liver disease, including acute fatty liver of pregnancy and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome.

METHODS

This was a case-control study comparing fetal fatty acid oxidation defects to the outcome of maternal liver disease. Fifty case infants with fatty acid oxidation defects were identified, with 25 matched controls collected per case. This generated a total of 50 case infants and 1,250 control infants. Pregnancies were evaluated for the presence of maternal liver disease (comprised of acute fatty liver of pregnancy, HELLP syndrome, and preeclampsia evolving into HELLP syndrome) using a conditional logistic regression model. Subgroup analysis compared long chain to short and medium chain fatty acid defects.

RESULTS

Maternal liver disease was noted in 16.00% of all fatty acid oxidation defect pregnancies compared with 0.88% in the general population (odds ratio 20.4, 95% confidence interval 7.82-53.2). These pregnancies demonstrated an 18.1-fold increase in maternal liver disease when compared with our matched population controls with unaffected fetuses. All classifications of fatty acid oxidation defects were at high risk of developing maternal liver disease. Long chain defects were 50 times more likely than controls to develop maternal liver disease and short and medium chain defects were 12 times more likely to develop maternal liver disease.

CONCLUSION

Maternal liver disease is significantly higher across the entire spectrum of fatty acid oxidation defects pregnancies compared with the matched control population. Notably, there is significant risk to the pregnancies with fetuses affected with short and medium chain defects, not just those with fetal long chain fatty acid oxidation defects as previously reported. Future studies should examine the pathophysiology of all infant fatty acid oxidation defects and its implications for maternal liver disease for improved future health outcomes.

LEVEL OF EVIDENCE

II-2.

Impaired fatty acid utilization in thioredoxin binding protein-2 (TBP-2)-deficient mice: a unique animal model of Reye syndrome

Thioredoxin binding protein-2 (TBP-2) is a negative regulator of thioredoxin and has multiple regulatory functions in cellular redox, growth, differentiation, apoptosis, and aging. To investigate the function of TBP-2 in vivo, we generated mice with targeted inactivation of TBP-2 (TBP-2-/- mice). Here, we show that TBP-2 expression is markedly up-regulated during fasting in wild-type mice, while TBP-2-/- mice were predisposed to death with bleeding tendency, as well as hepatic and renal dysfunction as a result of 48 h of fasting. The fasting-induced death was rescued by supplementation of glucose but not by that of oleic acid, suggesting that inability of fatty acid utilization plays an important role in the anomaly of TBP-2-/- mice. In these mice, plasma free fatty acids levels are higher, whereas glucose levels are lower than those of wild-type mice. Compared with wild-type mice, TBP-2-/- mice showed increased levels of plasma ketone bodies, pyruvate and lactate, indicating that Krebs cycle-mediated fatty acid utilization is impaired. Because the fatal impairment of fatty acid utilization is a characteristically metabolic feature of Reye (-like) syndrome, TBP-2-/- mouse may represent a novel model for investigating the pathophysiology of these disorders.

Homogeneous amplification nucleobase quenching assay to detect the E474Q LCHAD deficiency mutation

Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency is a rare and potentially fatal autosomal recessive disorder of fatty acid metabolism. Early institution of dietary therapy is essential and places a premium on rapid diagnosis. Pregnancy with an LCHAD-deficient fetus is often complicated in the third trimester by liver disease, particularly acute fatty liver of pregnancy. All cases of isolated LCHAD deficiency have at least one copy of the E474Q mutation in the gene encoding the alpha-subunit of the mitochondrial trifunctional protein. Previously published methods for detecting this mutation are based upon allele-specific restriction enzyme digestion of a DNA fragment generated by PCR, followed by gel electrophoresis to resolve the products. We have developed a faster and less expensive assay for the E474Q mutation using PCR followed directly by differential melting of a fluorescently labeled oligodeoxyribonucleotide probe, using nucleobase quenching to detect probe hybridization.

Impaired fatty acid oxidation as a cause of liver disease associated with hyperemesis gravidarum

Hyperemesis gravidarum (HG) is the most severe form of illness within the spectrum of nausea and vomiting of pregnancy. Liver disease, usually consisting of mild serum transaminase elevation, occurs in almost 50% of patients with HG. While multiple risk factors have been proposed, the etiology and underlying mechanism of maternal liver disease associated with HG remains unclear. In this report, we hypothesize that impairment of mitochondrial fatty acid oxidation (FAO) plays a role in the pathogenesis of maternal liver disease associated with HG. We hypothesize that women heterozygous for FAO defects develop HG associated with liver disease while carrying fetuses with FAO defects due to accumulation of fatty acids in placenta and subsequent generation of reactive oxygen species. Alternatively, it is possible that starvation leading to peripheral lipolysis and increased load of fatty acids in maternal-fetal circulation, combined with reduced capacity of the mitochondria to oxidize fatty acids in mothers heterozygous for FAO defects, can also cause HG and liver injury while carrying non-affected fetuses. The rationale for this hypothesis is discussed.

Maternal complications of multifetal pregnancy

This article reviews the common maternal complications encountered in multifetal gestations.

Neonatal screening for defects of the mitochondrial trifunctional protein

Long-chain l-3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency has been included in the routine neonatal screening program by the German screening commission. As tandem mass spectrometry (TMS) does not discriminate between the different defects of the mitochondrial trifunctional protein (MTP) screening for isolated LCHAD deficiency includes the detection of long-chain 3-ketoacyl-CoA thiolase and complete MTP deficiencies as well. We identified 11 patients with abnormalities of the MTP out of 1.2 million newborns screened in our laboratory during the last 6 years. Treatment was started on the day the screening result was obtained (day 3 to day 9 of life). Seven of these newborns developed satisfactorily during an observation period of up to 64 months. They had isolated LCHAD deficiency, four of them caused by the typical mutation (1528 G>C), three others had no molecular genetic analysis done or were shown to have previously unknown mutations. Four children did not survive, two of them showing complete deficiency of MTP and two showing deficiency of long-chain 3-ketoacyl-CoA thiolase. We conclude that, despite the rarity of the disease, screening for MTP deficiencies is justified based on the following criteria: improved quality of life for patients with isolated LCHAD deficiency, absence of stigmatisation of babies showing mild variants without necessity of treatment, no significant increase of the total number of false positive screening results, no false negative results to our knowledge. Finally, extension of analysis to MTP deficiencies is achieved without additional costs for screening laboratories already using TMS.

Sex Differences in Antiretroviral Therapy-Associated Intolerance and Adverse Events

Although women account for a substantial proportion of the global population infected with HIV, most clinical trials evaluating the safety and efficacy of specific antiretroviral therapy regimens have been preformed in predominantly male cohorts. Our knowledge of the sex differences associated with responses to these treatments is therefore limited. Potentially sex-specific influences, such as endogenous or exogenous hormones, could impact antiretroviral tolerance. Women also have different pharmacokinetic profiles for selected antiretrovirals compared with men. These factors could influence how women respond and react to antiretrovirals. Several observational studies have described a higher frequency of antiretroviral-related adverse effects among women compared with men. Women appear to be at an especially high risk for lactic acidosis, nevirapine-associated rashes and hepatotoxicity, and fat redistribution after highly active antiretroviral therapy exposure. Although a statistical association between antiretroviral toxicity and pregnancy has not been described, pregnancy may provide an additional influence on the toxicity of several antiretrovirals or antiretroviral combinations. Potential tolerability should be an important component in discussions of antiretroviral options among women.

Maternal heterozygosity for a mitochondrial trifunctional protein mutation as a cause for liver disease in pregnancy

Acute fatty liver of pregnancy (AFLP) and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome are serious complications of pregnancy associated with significant maternal and perinatal morbidity and mortality. In previous reports, we have documented an association between AFLP and fetal deficiency of long-chain 3-hydroxyacyl coenzyme A dehydrogenase (LCHAD) [N. Engl. J. Med. 340 (1999) 1723-1731; JAMA 288 (2002) 2163-2166]. LCHAD activity resides in the alpha-subunit of the mitochondrial trifunctional protein (MTP), a complex protein that catalyzes beta-oxidation of long chain fatty acids. In all reported cases, the fetus carried a common alpha-subunit MTP mutation (G1528C, E474Q) on one or both alleles. However, the association between fetal LCHAD deficiency and the maternal HELLP syndrome has been limited. Here, we report a case history of a 27-year-old black female who underwent Cesarean section for placenta previa and fetal distress at 36 weeks gestation. The newborn was a healthy male child. Post-delivery, the mother developed severe HELLP syndrome with complications resulting in death of the patient. We used single strand conformation variance and nucleotide sequence analyses to screen DNA isolated from the mother and the newborn for mutations in the MTP alpha-subunit. The mother was heterozygous for a novel mutation (C1072A, Q322K) in exon 11 of the LCHAD domain of the MTP, while the fetal genotype was completely normal. We hypothesize that, in some cases, maternal heterozygosity for an MTP mutation maybe sufficient to cause the development of maternal liver disease without carrying an affected fetus. Combination of the metabolic stress of pregnancy and other environmental stresses may overwhelm the heterozygous mother's capacity for effective metabolism of long chain fatty acids, leading to an accumulation of potentially toxic fatty acid metabolites in the maternal circulation with subsequent damage to the maternal liver.

The Association Between Acute Fatty Liver of Pregnancy and Fatty Acid Oxidation Disorders

Acute fatty liver of pregnancy is a relatively rare but potentially fatal liver disorder of late pregnancy. Recent advances in molecular diagnostic procedures provide evidence of a genetic basis for this condition and a link to offspring disorders in fatty acid oxidation. This relationship implies the need for genetic testing and follow-up of at-risk women and their neonates.

Carnitine content and expression of mitochondrial beta-oxidation enzymes in placentas of wild-type (OCTN2(+/+)) and OCTN2 Null (OCTN2(-/-)) Mice

Placenta requires energy to support its rapid growth, maturation, and transport function. Fatty acids are used as energy substrates in placenta, but little is known about the role played by carnitine in this process. We have investigated the role of carnitine in the expression of the enzymes involved in fatty acid beta-oxidation in placenta of OCTN2(-/-) mice with defective carnitine transporter (OCTN2). Heterozygous (OCTN2(+/-)) female mice were mated with heterozygous (OCTN2(+/-)) male mice. Pregnant mice were killed and fetuses and placentas were collected. Carnitine was measured using HPLC and tandem mass spectrometry. Immunohistochemistry was used to detect enzyme expression. Enzyme activities were measured spectrophotometrically. The fetal and placental weights were similar among the three genotypes (OCTN2(+/+), OCTN2(+/-), and OCTN2(-/-)). The levels of carnitine were markedly reduced (<20%) in homozygous OCTN2(-/-) null fetuses and placentas compared with wild-type OCTN2(+/+) controls. However, carnitine concentration in placenta was 2- to 7-fold higher than in the fetus in all three genotypes. Immunohistochemistry revealed that beta-oxidation enzymes are expressed in trophoblast cells. Catalytic activities of these enzymes were present at comparable levels in wild-type (OCTN2(+/+)) and homozygous (OCTN2(-/-)) mouse placentas, with the exception of SCHAD, for which activity was significantly higher in OCTN2(-/-) placentas than in OCTN2(+/+) placentas. These data show that placental OCTN2 is obligatory for accumulation of carnitine in placenta and fetus, that fatty acid beta-oxidation enzymes are expressed in placenta, and that reduced carnitine levels up-regulate the expression of SCHAD in placenta.