Total bile acid concentration a possible biomarker for coronary artery disease

29th November 2021

The total bile acid concentration is lower in patients with visible coronary artery disease and could be an important disease biomarker

The total bile acid concentration among those with visible coronary artery disease (CAD) as seen with coronary angiography was approximately 50% lower than in patients without CAD, indicating that this might serve as an important biomarker for the disease. This was the finding of a study by researchers from the department of Cardiology, Cochin Hospital, Paris, France.

Cardiovascular disease is the leading cause of death globally, accounting for an estimated 17.9 million deaths every year. Moreover, other evidence shows that in patients with non-alcoholic fatty liver disease (NAFLD), who have an excessive fat deposition in the liver, there is a dysregulation of bile acid (BA) metabolism. Finally, one systematic review in 2013, revealed how NAFLD is a strong independent predictor of cardiovascular disease. Taken together, these findings might suggest that dysfunctional BA metabolism could be indicative of CAD.

For the present study, the French team sought to explore the relationship between total bile acid concentration and CAD by measuring the level of acids in patients referred for coronary angiography and who could well have CAD. In addition, the team also measured the concentration of 7-alpha C4, which serves as a marker for the production of bile acids by the liver to determine whether there was any correlation with CAD.

Findings

A total of 80 patients with a mean age of 61.5 years (61% male) were recruited, 45 who presented with significant CAD on angiography and the remainder who were normal. Both groups were comparable apart from the CAD group being significantly older (66 vs 57 years, p = 0.004), including more men (73% vs 49%, p = 0.02) and with a significantly higher diastolic pressure (77 vs 72 mmHg, p = 0.04).

After adjustment for age and gender, the total bile acid concentration was highly predictive of CAD, with an area under the curve of 83.6% (95% CI 74.5% – 92.8%) and an odds ratio, OR of 0.51 (95% CI 0.31 – 0.85, p = 0.01). In other words, bile acid levels were approximately 50% lower in patients with CAD. From a total of 28 different bile acids, the researchers identified that one particular BA, GCDCA acid, was also predictive of CAD (AUC = 83.6%) and with a similar odds ratio (OR = 0.60, 95% CI 0.01 – 0.51, p = 0.01). A further observation was how the levels of 7-alpha C4 was similar in both groups (0.13 vs 0.12 micromol/L). One interesting finding was how among 17 patients who had been prescribed statins, the mean concentration of total bile acid, doubled (0.68 to 1.37 micromol/L, p = 0.01) after one month of treatment.

In discussing these results, the authors suggested that the total bile acid concentration might serve as a natural braking mechanism and which protected against the development of atheromatous plaques. They concluded by proposing that GCDCA could serve as a biomarker and predictor of visible atheroma in patients with CAD.

Citation

Nguyen CC et al. Circulating bile acids concentration is predictive of coronary artery disease in human Sci Rep 2021