ALTERATIONS in bile acid metabolism may play an underappreciated role in the progression of chronic kidney disease (CKD), according to new research analysing serum and urine bile acid profiles in patients with advanced disease.
Dysbiosis of the gut microbiota is increasingly recognised as a contributor to systemic inflammation and the accumulation of uremic toxins in CKD. Bile acids, which are key metabolic products of gut bacteria, have been implicated in metabolic and inflammatory pathways, but their specific involvement in CKD remains poorly defined. To address this gap, researchers conducted a cross-sectional study comparing bile acid profiles in patients with advanced CKD and individuals with normal renal function.
The study included 29 patients with advanced CKD and 30 age- and sex-matched controls with normal renal function. Comprehensive profiling of serum and urinary bile acids was performed to assess differences between the groups and explore associations with kidney function.
Sulfate-Conjugated Bile Acids Increased in CKD
Total serum bile acid concentrations did not differ significantly between patients with CKD and controls. However, marked differences were observed in bile acid composition. Patients with CKD had significantly lower serum levels of unconjugated bile acids and substantially higher levels of sulfate-conjugated bile acids compared with individuals with normal renal function. These findings suggest altered bile acid processing or clearance in advanced kidney disease.
In contrast to serum findings, urinary bile acid excretion was markedly reduced in CKD. Total urinary bile acid levels, along with most bile acid subgroups, were significantly lower in patients with CKD, consistent with impaired renal handling of these metabolites.
Importantly, several specific serum bile acids showed significant associations with declining kidney function. Higher levels of ursodeoxycholic acid, chenodeoxycholic acid, and sulfate-conjugated bile acids were independently associated with lower estimated glomerular filtration rate, even after adjusting for demographic factors and diabetes status.
The authors conclude that while overall serum bile acid levels may remain unchanged, the composition and conjugation patterns of bile acids are significantly altered in advanced CKD. These findings support the concept that disrupted bile acid metabolism is linked to kidney disease progression.
Implications for Future CKD Research
Although limited by its small sample size and cross-sectional design, the study provides novel insights into bile acid dysregulation in CKD. The authors suggest that bile acid profiling could help clarify disease mechanisms and may point towards new therapeutic targets aimed at modulating gut–kidney metabolic pathways.
Reference
Koshida T et al. A comprehensive analysis of serum and urine bile acid profiles in chronic kidney disease: an exploratory study of clinical associations. Nephrology. 2026; ;31(1):e70156.
