Dysfunction of drug transporters significantly affects therapeutic outcomes and drug efficacy in patients with liver injury. Clinical and experimental evidence demonstrates that liver injury involves complex inter-organ interactions among the brain, eye, liver, intestine, and kidney. Recent advances in basic and clinical research have illuminated the physiologic and molecular mechanisms underlying transporter alterations in liver injury, particularly those associated with bilirubin, reactive oxygen species, ammonia, bile acid, and inflammatory factors. Notably, the influence of these transporter modifications on drug pharmacokinetics in liver injury patients remains inadequately understood. Additional research is necessary to fully comprehend these effects and their therapeutic implications. The documented alterations of transporters in distant organs across various liver diseases indicate that dosage modifications may be required when administering transporter-substrate drugs, including both traditional Chinese and Western medicines, to patients with liver dysfunction. This strategy helps maintain drug concentrations within therapeutic ranges while reducing adverse reactions. Furthermore, when utilizing transporter inducers or inhibitors clinically, consideration of their long-term effects on transporters and subsequent therapeutic impact is essential. Careful attention must be paid to avoid compromising the elimination of toxic metabolites and proteins when inhibiting these transporters. Similarly, prudent use of inducers or inducer-type therapeutic drugs is necessary to prevent enhanced drug resistance. This review examines recent clinical and experimental findings regarding the inter-organ interaction of drug transporters in liver injury conditions and their clinical relevance.
Humans ; Liver/drug effects* ; Animals ; Chemical and Drug Induced Liver Injury/metabolism* ; Membrane Transport Proteins/metabolism* ; Biological Transport ; Liver Diseases/drug therapy* ; Pharmaceutical Preparations/metabolism*

Type 2 diabetes (T2D) is often accompanied with an induction of retinaldehyde dehydrogenase 1 (RALDH1 or ALDH1A1) expression and a consequent decrease in hepatic retinaldehyde (Rald) levels. However, the role of hepatic Rald deficiency in T2D progression remains unclear. In this study, we demonstrated that reversing T2D-mediated hepatic Rald deficiency by Rald or citral treatments, or liver-specific Raldh1 silencing substantially lowered fasting glycemia levels, inhibited hepatic glucogenesis, and downregulated phosphoenolpyruvate carboxykinase 1 (PCK1) and glucose-6-phosphatase (G6PC) expression in diabetic db/db mice. Fasting glycemia and Pck1/G6pc mRNA expression levels were strongly negatively correlated with hepatic Rald levels, indicating the involvement of hepatic Rald depletion in T2D deterioration. A similar result that liver-specific Raldh1 silencing improved glucose metabolism was also observed in high-fat diet-fed mice. In primary human hepatocytes and oleic acid-treated HepG2 cells, Rald or Rald + RALDH1 silencing resulted in decreased glucose production and downregulated PCK1/G6PC mRNA and protein expression. Mechanistically, Rald downregulated direct repeat 1-mediated PCK1 and G6PC expression by antagonizing retinoid X receptor α, as confirmed by luciferase reporter assays and molecular docking. These results highlight the link between hepatic Rald deficiency, glucose dyshomeostasis, and the progression of T2D, whilst also suggesting RALDH1 as a potential therapeutic target for T2D.