Mitochondrial DNA depletion syndrome (MTDPS) is a group of severe mitochondrial disorders caused by nuclear gene variants that affect mitochondrial DNA (mtDNA) replication and nucleotide synthesis. Deoxyguanosine kinase deficiency is one of the most common subtypes, typically presenting with liver dysfunction in infancy and having a poor prognosis. We report a case of MTDPS presenting with cholestasis and mild hyperlactatemia in the neonatal period, which complicated early diagnosis. Histopathological and genetic analyses established the diagnosis. The patient, a female born at 36 weeks and 1 day of gestation, weighing 2124 g, developed cholestasis, poor feeding, and failure to thrive. Hyperlactatemia was not evident at presentation but gradually increased during the clinical course. Based on suspected mitochondrial disease, mitochondrial cocktail therapy was initiated on day 64. Liver transplantation was not feasible owing to cardiac and neurological complications, and conservative treatment was continued. However, the patient died of multiple organ failure on day 89. Postmortem liver biopsy showed a markedly reduced mtDNA copy number (8.1% of control), and genetic testing revealed a homozygous c.609_610del (p.Tyr204fs) variant in the DGUOK gene (NM_080916.3), confirming the diagnosis of DGUOK-related MTDPS. This case highlights that hyperlactatemia may be absent or only mild in the early stages of MTDPS, making timely diagnosis challenging. Mitochondrial functional analysis and genetic testing should be considered early in infants with unexplained cholestasis and liver failure, regardless of the lactate levels.

Liver fibrosis is a common pathological process, leading to the development of end-stage liver diseases. It is triggered by various etiological drivers including viral hepatitis, metabolic-associated steatotic liver disease (MASLD), and cholestasis. Given the substantial impact of liver fibrosis on individuals and its associated mortality rates, effective management of this condition is crucial for improving public health. Despite a growing number of preclinical studies and clinical trials, a systematic synthesis remains lacking. In this review, the molecular panorama of liver fibrogenesis is summarized at first, encompassing etiological drivers of chronic liver injury, key cellular players, core signaling pathways, and extracellular matrix dynamics. Therapeutic interventions in preclinical or clinical stages are systematically classified into two main categories: etiological treatment as the foundational approach and mechanism-based antifibrotic therapies. Emerging and future therapeutic strategies, including those targeting gut-liver axis, gut microbiota, and cell-based therapies, are also addressed along with inherent challenges. Furthermore, future perspectives centered on precision medicine, combination therapies, novel target discovery, and advanced drug delivery systems are emphasized. This review offers a comprehensive overview of the etiologies, diagnostic approaches, pathogenic mechanisms, current development of antifibrotic agents, and prospects for future therapeutic directions of liver fibrosis.

Bile acids are crucial indicators for the diagnosis of liver diseases, including cholestasis, which necessitates robust and versatile analytical methods for comprehensive analysis. This study presents a validated UPLC-MS/MS method for the quantitative determination of 23 bile acids in rat plasma, ileal tissues, and feces, encompassing free primary and secondary bile acids as well as taurine-conjugated and glycine-conjugated bile acids. All bile acids were qualitatively and quantitatively assessed within 24 min. The method demonstrated detection limits of 0.01-0.1 ng/mL, and quantification limits of 0.1-1 ng/mL. Performance evaluation demonstrated excellent specificity and good method robustness. Both intra-day and inter-day precision were below 12.4%, with accuracy ranging from 86.8% to 113%. Extraction recoveries were 90.7-108% with RSD of 1.11-11.9%, while matrix effects were 93.5-109% with RSD of 0.30-11.6%, indicating high extraction efficiency and negligible matrix interference. The analytes were stable under the tested conditions, with stability values from 86.1% to 113%. In an estrogen-induced cholestatic rat model, the UPLC-MS/MS method detected increased conjugated bile acids in plasma and a disturbed primary-to-secondary bile acid ratio in ileal and fecal samples, indicating impaired enterohepatic circulation. The method was fully validated in accordance with the Guideline on Bioanalytical Method Validation and demonstrated reliable, stable, and consistent quantification of bile acids across complex biological matrices. This work supports mechanistic studies of cholestasis and facilitates the identification of potential clinical biomarkers.

Intrahepatic cholestasis of pregnancy (ICP) is a gestational metabolic disorder characterized by impaired maternal bile acid homeostasis. Emerging evidence suggests that dysregulated iron metabolism may contribute to the pathophysiology of ICP. Nevertheless, the specific alterations in iron metabolism among ICP patients remain unexplored.

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disorder characterized by elevated total bile acid (TBA) levels, leading to adverse maternal and fetal outcomes. While genetic factors contribute to ICP and bile acid metabolism, the underlying mechanisms remain incompletely understood, particularly in East Asian populations. We conducted a genome-wide association study (GWAS) in 13,357 pregnant women from a Chinese cohort to investigate genetic determinants of TBA levels and ICP. Meta-analysis was performed by combining our data with the Shenzhen cohort. Post-GWAS analyses included pathway enrichment, integrative analysis with liver single-cell RNA sequencing (scRNA-seq) data, and Mendelian randomization (MR). We identified genome-wide significant associations at CYP7A1 (rs4738680, p = 1.08 × 10-10) and SLC39A9 (rs17107007, p = 3.46 × 10-28) for TBA, and at SLC39A9 (rs17107007, p = 3.34 × 10-16) for ICP. Pathway analysis highlighted bile acid synthesis and metabolism pathways for TBA and immune-related pathways for ICP. Integrative scRNA-seq analysis revealed enrichment of TBA-associated genes in hepatocytes and ICP-associated genes in neutrophils. MR analysis suggested a potential causal effect of estrone on TBA levels. Our findings provide novel insights into the genetic architecture of TBA and ICP, emphasizing the roles of bile acid metabolism in hepatocytes and immune dysregulation in ICP pathogenesis. The identified genetic loci and pathways may inform future research on risk prediction and targeted therapies for ICP.

Autoimmune liver diseases (AILDs) are a group of liver diseases characterized by immune dysfunction. Recent studies have proposed a potential correlation among immune cells, cytokines, and AILDs. However, the causal nature of this relationship remains to be elucidated. Summary-level Genome-Wide Association Studies (GWAS) statistical data for primary biliary cholangitis and primary sclerosing cholangitis were obtained from FinnGen, while autoimmune hepatitis and immune trait statistics were sourced from the GWAS Catalog. GWAS data for 41 inflammatory cytokines were acquired from the University of Bristol. The inverse-variance weighted method was the primary Mendelian randomization (MR) analysis method, with sensitivity and inverse MR analyses performed to assess result stability. Under the premise of satisfying the MR hypothesis, our analysis supported the existence of potential causal relationships between different immunophenotypes, cytokines, and AILDs. 10 immune cell phenotypes and 7 cytokines with potential causal relationships with AILDs were identified. For different types of AILDs, 4 immune phenotypes and 4 cytokines were found to be associated with primary biliary cholangitis, 4 immune phenotypes and 2 immune factors were associated with primary sclerosing cholangitis, and 3 immune phenotypes and 1 cytokine were associated with autoimmune hepatitis. However, we did not find any evidence of reverse causality between immunophenotypes, cytokines, and AILDs. MR analysis found a potential causal relationship between several immune phenotypes, cytokines, and AILDs, suggesting differences in immune responses across various types of AILDs.