Pediatric metabolic liver diseases: Evolving role of liver transplantation

Special Techniques of Liver Transplantation: Living Donor Liver Transplantation With Right Posterior Sector Grafts and Extended Left Lobe Grafts; Auxiliary Partial Orthotopic Liver Transplantation, and Dual-Lobe Liver Transplantation

Living donor liver transplantation (LDLT) constitutes the majority of liver transplants in Asia and advancements in LDLT techniques have expanded the range of allografts beyond the commonly used right lobe (RL). This review provides a comprehensive overview of lesser-known variants of allografts and LDLT techniques which include right posterior sector grafts (RPSG), dual-lobe liver transplantation (DLLT), auxiliary partial orthotopic liver transplantation (APOLT), and extended left lobe grafts with caudate concentrating on the technical aspects, current evidence, and their indications in contemporary practice of LDLT. The first section examines RPSGs, focussing on their potential as an alternative to RL grafts particularly when volumetric studies indicate a larger right posterior sector in donors. It addresses donor selection, surgical techniques, and potential complications. Next, the article explores DLLT, which optimizes graft volume through partial grafts from two donors. The emphasis is on the ethical considerations, surgical challenges, and haemodynamic risks, such as graft atrophy, highlighting the importance of careful donor selection and meticulous planning. The section on APOLT covers its application in treating acute liver failure (ALF) and metabolic liver diseases. The technique's ability to support liver function in ALF while avoiding long-term immunosuppression when the native liver regenerates is discussed, along with patient selection criteria and follow-up requirements. Finally, the review addresses left lobe grafts with caudate used in smaller adults and older children to increase functional graft volume and improve outcomes.

Identification of a biallelic MMUT variant (p.Thr230Arg) and its global perspective on clinical management

BACKGROUND

Methylmalonic acidemia (MMA), type mut (0) is a rare type of genetic inborn error of metabolism (IEM) that is caused by aberrant malonyl-CoA mutase activity. Diagnosing IEM can be challenging due to its inherited onset and varying degrees of severity.

METHODS AND RESULTS

In the present study, a consanguineous Pakistani family suspected of IEM was genetically analyzed using whole exome sequencing. A biallelic variant c.689 C > G (p.Thr230Arg) in MMUT was identified to be the causative factor of the disease, which helped in establishing the accurate diagnosis in the family to be MMA mut(0) type. On the basis of the genetic findings, the patient's condition was appropriately managed through a supportive nutrition plan and administration of oral L-carnitine.

CONCLUSIONS

Identification of MMUT mutation through whole exome sequencing was helpful in solving the family and devising targeted management strategies. This study highlights the utility of genetic analysis in diagnosing and treating metabolic disorders like MMA in Pakistani inbred population.

Lipid nanoparticles as the drug carrier for targeted therapy of hepatic disorders

The liver, a complex and vital organ in the human body, is susceptible to various diseases, including metabolic disorders, acute hepatitis, cirrhosis, and hepatocellular carcinoma. In recent decades, these diseases have significantly contributed to global morbidity and mortality. Currently, liver transplantation remains the most effective treatment for hepatic disorders. Nucleic acid therapeutics offer a selective approach to disease treatment through diverse mechanisms, enabling the regulation of relevant genes and providing a novel therapeutic avenue for hepatic disorders. It is expected that nucleic acid drugs will emerge as the third generation of pharmaceuticals, succeeding small molecule drugs and antibody drugs. Lipid nanoparticles (LNPs) represent a crucial technology in the field of drug delivery and constitute a significant advancement in gene therapies. Nucleic acids encapsulated in LNPs are shielded from the degradation of enzymes and effectively delivered to cells, where they are released and regulate specific genes. This paper provides a comprehensive review of the structure, composition, and applications of LNPs in the treatment of hepatic disorders and offers insights into prospects and challenges in the future development of LNPs.

Impact of citrulline substitution on clinical outcome after liver transplantation in carbamoyl phosphate synthetase 1 and ornithine transcarbamylase deficiency

Carbamoyl phosphate synthetase 1 (CPS1) and ornithine transcarbamylase (OTC) deficiencies are rare urea cycle disorders, which can lead to life-threatening hyperammonemia. Liver transplantation (LT) provides a cure and offers an alternative to medical treatment and life-long dietary restrictions with permanent impending risk of hyperammonemia. Nevertheless, in most patients, metabolic aberrations persist after LT, especially low plasma citrulline levels, with questionable clinical impact. So far, little is known about these alterations and there is no consensus, whether l-citrulline substitution after LT improves patients' symptoms and outcomes. In this multicentre, retrospective, observational study of 24 patients who underwent LT for CPS1 (n = 11) or OTC (n = 13) deficiency, 25% did not receive l-citrulline or arginine substitution. Correlation analysis revealed no correlation between substitution dosage and citrulline levels (CPS1, p = 0.8 and OTC, p = 1). Arginine levels after liver transplantation were normal after LT independent of citrulline substitution. Native liver survival had no impact on mental impairment (p = 0.67). Regression analysis showed no correlation between l-citrulline substitution and failure to thrive (p = 0.611) or neurological outcome (p = 0.701). Peak ammonia had a significant effect on mental impairment (p = 0.017). Peak plasma ammonia levels correlate with mental impairment after LT in CPS1 and OTC deficiency. Growth and intellectual impairment after LT are not significantly associated with l-citrulline substitution.

mRNA vaccines in disease prevention and treatment

mRNA vaccines have emerged as highly effective strategies in the prophylaxis and treatment of diseases, thanks largely although not totally to their extraordinary performance in recent years against the worldwide plague COVID-19. The huge superiority of mRNA vaccines regarding their efficacy, safety, and large-scale manufacture encourages pharmaceutical industries and biotechnology companies to expand their application to a diverse array of diseases, despite the nonnegligible problems in design, fabrication, and mode of administration. This review delves into the technical underpinnings of mRNA vaccines, covering mRNA design, synthesis, delivery, and adjuvant technologies. Moreover, this review presents a systematic retrospective analysis in a logical and well-organized manner, shedding light on representative mRNA vaccines employed in various diseases. The scope extends across infectious diseases, cancers, immunological diseases, tissue damages, and rare diseases, showcasing the versatility and potential of mRNA vaccines in diverse therapeutic areas. Furthermore, this review engages in a prospective discussion regarding the current challenge and potential direction for the advancement and utilization of mRNA vaccines. Overall, this comprehensive review serves as a valuable resource for researchers, clinicians, and industry professionals, providing a comprehensive understanding of the technical aspects, historical context, and future prospects of mRNA vaccines in the fight against various diseases.

mRNA-Based Approaches to Treating Liver Diseases

Diseases that affect the liver account for approximately 2 million deaths worldwide each year. The increasing prevalence of these diseases and the limited efficacy of current treatments are expected to stimulate substantial growth in the global market for therapeutics that target the liver. Currently, liver transplantation is the only curative option available for many liver diseases. Gene therapy represents a valuable approach to treatment. The liver plays a central role in a myriad of essential metabolic functions, making it an attractive organ for gene therapy; hepatocytes comprise the most relevant target. To date, viral vectors constitute the preferred approach to targeting hepatocytes with genes of therapeutic interest. Alternatively, mRNA-based therapy offers a number of comparative advantages. Clinical and preclinical studies undertaken to treat inherited metabolic diseases affecting the liver, cirrhosis and fibrosis, hepatocellular carcinoma, hepatitis B, and cytomegalovirus using lipid nanoparticle-encapsulated mRNAs that encode the therapeutic or antigenic protein of interest are discussed.

A look into hemostatic characteristics during pediatric liver transplantation using the thromboelastometry (ROTEM® ) test

There is a paucity of evidence about the coagulation profile regarding the complexity of children undergoing liver transplantation (LT). This study aimed to investigate intraoperative hemostatic changes during pediatric LT according to the etiology for LT and examine the ability of rotational thromboelastometry (ROTEM^® , TEM International GmbH, Munich, Germany) as a point-of-care monitoring method. We evaluated 106 patients aged 3 months to 17 years undergoing LT for acute liver failure (ALF) and chronic liver disease, which consists of patients with cholestatic disease, metabolic/genetic disease, and cancer. A total of 731 ROTEM^® measurements, including 301 ellagic acid to initiate clotting via the intrinsic pathway, 172 tissue factor to initiate the extrinsic clotting cascade (EXTEM), and 258 cytochalasin D to inhibit platelet activity reflecting fibrinogen (FIBTEM), were analyzed at predetermined time points (the preanhepatic, anhepatic, and postreperfusion phases). We simultaneously conducted conventional coagulation tests. In children with ALF, preanhepatic measurements of conventional coagulation tests and ROTEM^® showed a more hypocoagulable state than other diseases. During LT, the coagulation profile was deranged, with a prolonged clotting time and reduced clot firmness, changes that were more profound in the cholestatic disease group. Maximum clot firmness (MCF) on EXTEM and FIBTEM were well correlated with the platelet count and fibrinogen concentration (r = 0.830, p < 0.001 and r = 0.739, p < 0.001, respectively). On the EXTEM, MCF with 30 mm predicted a platelet count <30,000/mm³ (area under the curve, 0.985), and 6 mm predicted a fibrinogen concentration <100 mg/dl on the FIBTEM (area under the curve, 0.876). However, the activated partial thromboplastin time and prothrombin time were significant but only weakly correlated with the clotting time on the ROTEM^® . In children undergoing LT, coagulation profiles depend on the etiology for LT. During LT, ROTEM^® parameters could help detect thrombocytopenia and hypofibrinogenemia and guide transfusion therapy as a point-of-care monitoring method.

Giant Cell Hepatitis in Copper Toxicosis

Cholestatic jaundice in new born and infants results from biliary obstruction or hepatocellular dysfunction. Biliary atresia (BA) and Idiopathic neonatal hepatitis comprises the major aetiology. Cholestasis due to toxins is rare in infants. Indian childhood cirrhosis (ICC) and ICC like diseases have been described in infants. Herein, authors are describing a case of infantile cholestasis presenting at 4 months of age who was diagnosed to have copper related hepatotoxicosis on liver biopsy. Copper tumblers were used for preparation of formula milk that likely was the source of exogenous copper and the child improved well after removing the source of exogenous copper.

An Italian expert consensus on the management of alpha1-antitrypsin deficiency: a comprehensive set of algorithms

BACKGROUND

Alpha1-antitrypin deficiency (AATD) is a genetic-based risk condition, mainly affecting the lungs and liver. Despite its wide distribution, it is largely underdiagnosed, thus being considered a rare disease, and is consequently managed in ad hoc reference centers. Unfortunately, an easy-to-use algorithm for managing such a complex disease is still lacking.

METHODS

An expert consensus meeting was conducted among experts in the management of AATD to build a comprehensive algorithm, including diagnosis, monitoring, AAT therapy, rehabilitation and lung transplantation, and liver disease, that could serve as a guide for physicians and treating centers. A panel of AATD specialists evaluated the results of their work.

RESULTS

Diagnosis is the most delicate phase, and awareness about this condition should be raised among GPs. A set of recommendations has been written about the most suitable follow-up visits. Augmentation therapy with AAT may be useful to reduce the progression of emphysema and lung function decline in selected patients. Exercise capacity may be improved by pulmonary rehabilitation and, in selected cases, by lung volume reduction or lung transplantation. Support therapies are needed for those who develop liver disease, and, in selected cases, liver transplantation may be considered. Patients should be carefully educated about their lifestyle, including smoking cessation, body weight control, and reduced alcohol intake.

CONCLUSIONS

The proposed algorithm obtained the endorsement of the Italian Society of Pneumology (SIP). However, further studies and additional clinical data are required to confirm the validity of these recommendations.

Not only a small liver - The pathologist's perspective in the pediatric liver transplant setting

Pediatric liver transplantation represents a safe and long-lasting treatment option for various disease types, requiring the pathologist's input. Indeed, an accurate and timely diagnosis is crucial in reporting and grading native liver diseases, evaluating donor liver eligibility and identifying signs of organ injury in the post-transplant follow-up. However, as the procedure is more frequently and widely performed, deceptive and unexplored histopathologic features have emerged with relevant consequences on patient management, particularly when dealing with long-term treatment and weaning of immunosuppression. In this complex and challenging scenario, this review aims to depict the most relevant histopathologic conditions which could be encountered in pediatric liver transplantation. We will tackle the conditions representing the main indications for transplantation in childhood as well as the complications burdening the post-transplant phases, either immunologically (i.e., rejection) or non-immunologically mediated. Lastly, we hope to provide concise, yet significant, suggestions related to innovative pathology techniques in pediatric liver transplantation.