Albumin in Chronic Liver Disease: Structure, Functions and Therapeutic Implications

Bibliographic info

• Authors: Rosaria Spinella, Rohit Sawhney, Rajiv Jalan
• Journal: Hepatology International, 2016 (published online September 2015; Asian Pacific Association for the Study of the Liver)
• Institution: University College London / Royal Free Hospital, UK (Jalan group — UCL Liver Failure Group)

Key question (review scope)

What are the structural, functional, and therapeutic implications of albumin abnormalities in chronic liver disease?

Content summary

HSA structure (review)

• 585 aa; three domains (I, II, III); 34 disulfide bonds; Cys34 = only free thiol
• Synthesized by hepatocytes; ~10–15 g/day; half-life 16–20 days
• Flexible structure enabling binding of diverse ligands (fatty acids, bilirubin, drugs, metals, hormones)

Key non-oncotic functions reviewed

Function	Mechanism	Clinical relevance in CLD
Antioxidant	Cys34 thiol scavenges ROS/RNS; binds free metals (Cu, Fe) at N-terminus; inhibits lipid peroxidation	HNA1/HNA2 rise = antioxidant capacity lost
Drug/toxin binding	Two Sudlow sites (I: bilirubin/warfarin; II: benzodiazepines/fatty acids); N-terminal metal binding	Impaired in cirrhosis → drug toxicity ↑
Immunomodulation	Binds and neutralizes bacterial endotoxin; inhibits complement activation; modulates neutrophil function	Reduced in CLD → immune dysfunction
Endothelial stabilization	Direct interaction with endothelial cells → preserves vascular permeability; reduces capillary leak	Loss → ascites, edema
Oncotic/volume	High MW; negative charge	Reduced in cirrhosis → ascites formation

Structural changes in CLD

• HNA1 (reversible oxidation): increases in CLD; related to oxidative stress
• HNA2 (irreversible oxidation): elevated, correlates with severity; non-recoverable
• Glycation: non-enzymatic, usually modest in CLD (see biphasic pattern)
• Truncations (N/C-terminal)
• Concept of “effective albumin”: fraction with intact structure and function — introduced here as a key concept for CLD management
• Jalan et al. (2009): EPR spectroscopy shows reduced fatty acid binding in decompensated cirrhosis → seminal EPR paper

Therapeutic implications

• Albumin infusion indications: SBP, large-volume paracentesis, hepatorenal syndrome — established
• Beyond volume expansion: immunomodulatory, antioxidant, endothelial effects of functional albumin
• TARGET study and ATTIRE study concept (at time of writing): long-term albumin infusion to maintain serum albumin >30–35 g/L
• Distinction between albumin as volume expander (oncotic) vs multi-functional therapeutic (non-oncotic)

Clinical context

• Disease: Liver fibrosis / cirrhosis (compensated and decompensated)
• Implication: A single molecule (albumin) serves as both a biomarker (measuring structural damage) and a therapeutic target (restoring functional capacity)

Connections

• HSA — comprehensive functional and structural reference
• Oxidation — HNA1/HNA2 clinical significance reviewed
• Liver fibrosis — CLD context throughout
• domenicali-2014 — seminal paper cited for isoform profiling and native HSA as survival predictor
• baldassarre-2021-ealb — effective albumin concept operationalized 5 years later; this review previews it
• naldi-2017-review — complementary analytical-focused review (same year, different focus)
• fernandez-2019 — albumin therapy RCT testing the non-oncotic effects hypothesized here
• bernardi-2023 — effective albumin paradigm perspective article from Bologna group senior author

Take home notes

• This is the Jalan group’s (UCL) perspective on albumin in CLD — important because Jalan is one of the main champions of long-term albumin infusion as a disease-modifying therapy (PILOT/TARGET/ATTIRE studies).
• The review articulates the “effective albumin” concept clearly before it was operationalized by baldassarre-2021-ealb — shows that the concept was in the air across multiple European groups simultaneously.
• The endothelial stabilization function of albumin is underappreciated — loss of this function could contribute to the capillary leak and ascites formation in advanced cirrhosis independently of low oncotic pressure.
• For ALBOM context: Spinella/Jalan reinforce that albumin measurement by concentration alone is insufficient. This provides the clinical justification for why an isoform-based approach (ALBOM) is superior.