Is there an association between the plasma levels of uremic toxins from gut microbiota and anemia in patients on hemodialysis?

Abstract

Background: Anemia is one of the most frequent complications in patients with chronic kidney disease (CKD). Despite being multifactorial, the relative or absolute deficiency of erythropoietin production is the leading cause. Recent studies have shown that uremic toxins produced by the gut microbiota also may play a role in the genesis of anemia in these patients.

Objective: To evaluate the possible association between uremic toxins plasma levels and anemia in patients with CKD on hemodialysis (HD).

Methods: This cross-sectional study evaluated one hundred fifty-four patients (53.2% men, 51.2 ± 11.2 years, hemoglobin (Hb) levels of 11.2 ± 1.6 g/dL). Biochemical variables such as urea, creatinine, hemoglobin, hematocrit, were measured according to standard methods and uremic toxins such as indoxyl sulfate (IS), indole-3-acetic acid (IAA), p-cresyl sulfate (p-CS) plasma levels were measured by reverse-phase high-performance liquid chromatography (RP-HPLC).

Results: The levels of uremic toxins such as IS, IAA, p-CS were increased in all patients. However, no correlation was found between uremic toxins plasma levels and anemia parameters. Only patients with Hb < 11 g/dL presented a negative correlation between hematocrit and IAA plasma levels.

Conclusion: There is no strong evidence that uremic toxins produced by the gut microbiota may be associated with anemia in patients with CKD on HD.

Keywords: Anemia; Chronic kidney disease; Erythropoiesis; Indole-3-acetic acid, p-cresyl sulfate; Indoxyl sulfate; Iron; Uremic toxins.