Efficacy of novel activated bamboo charcoal in reducing uremic toxins and enhancing kidney function in chronic kidney disease patients: a pilot randomized controlled trial

Abstract

Background: The role of uremic toxins in the progression of chronic kidney disease (CKD) and novel treatments to mitigate their effects are critical areas of research. This pilot study investigated the efficacy of a novel activated bamboo charcoal and/or probiotics in reducing uremic toxins and improving renal function in CKD patients.

Methods: This prospective, randomized, open, blinded end-point (PROBE) study included patients with stage 3 CKD. Patients were randomly assigned to one of four groups: activated bamboo charcoal (ABC), probiotics, ABC with probiotics, or standard treatment for 3 months.

Results: A total of 46 patients were enrolled (mean age 66.7 ± 11.5 years, 71.7% male). The ABC and ABC with probiotics groups showed a significant reduction in serum levels of the uremic toxins trimethylamine N-oxide (TMAO), p-cresyl sulfate (PCS), indoxyl sulfate (IS), and phenyl sulfate (PS) after 3 months of treatment (all p < 0.05). There was a particularly pronounced decrease in the percentage of IS in both the ABC group (-23.9 ± 28.9% vs. 33.9 ± 63.4%, p = 0.005) and the ABC with probiotics group (-29.3 ± 30.6% vs. 33.9 ± 63.4%, p = 0.009). The eGFR change ratio also significantly improved in the ABC group compared to the control group (4.6 ± 10.2% vs. -8.6 ± 12.5%, p = 0.011). However, the probiotics group did not exhibit a similar reduction in uremic toxins or an improvement in the eGFR.

Conclusion: This study suggested that ABC significantly reduced uremic toxins and might have potential in improving eGFR in CKD stage 3 patients over a 3-month period. These findings suggest a potential protective effect of ABC on kidney function, highlighting the need for further large-scale, long-term randomized controlled trials to confirm these results.

Keywords: Activated bamboo charcoal; Chronic kidney disease; Indoxyl sulphate; Phenyl sulfate; Probiotics; TMAO; p-Cresyl sulfate.

Figure 1. Flow diagram of the CONSORT study.

The stages of the CONSORT study, beginning with the recruitment of the patients, followed by their allocation into intervention, and analysis.

Figure 2. Correlation matrix and scatter plot matrix of clinical and biochemical parameters.

Upper triangular panels display the Pearson correlation coefficients between pairs of parameters. The lower triangular panels contain scatter plots with fitted regression lines and 95% confidence intervals, showing the relationships between pairs of parameters. Significant correlations are highlighted with asterisks: ***p < 0.001, **p < 0.01, *p < 0.05.

Figure 3. Differential changes in percentage of biomarkers illustrated by circular bar plot.

This illustrates the percentage changes (delta %) in various biomarkers across the four distinct treatment groups. The biomarkers assessed include TMAO, PCS, PS, IS, eGFR, and UACR. The bars represent the delta (%) from baseline (V0) to follow-up (V1), with each treatment group denoted by a different color: P+A (red), A (dark blue), P (light blue), and C (beige). TMAO, PCS, PS, and UACR exhibited no significant variations. IS exhibited a significant reduction in the P+A groups and P groups; the other groups showed less pronounced changes. eGFR changes were improved in group A compared with group C. Asterisks indicate statistically significant changes (*p < 0.05) within each biomarker. The plot highlights the differential impacts of various treatment regimens on key metabolic and kidney function biomarkers. Red asterisks indicate statistically significant differences between V0 and V1 within each treatment group (*p < 0.05). The treatment groups are denoted as follows: P+A, combined probiotic active bamboo charcoal; A, active bamboo charcoal; P, probiotic; C, control.

Figure 4. Changes in biomarkers over time in different treatment groups.

This figure depicts the distribution and changes in different biomarkers across treatment groups at two time points (baseline (V0) and 3 months after treatment (V1)). (A–F) The log-transformed levels of specific biomarkers. Violin plots display the density of the data points, while the central black dot and vertical line indicate the median and interquartile range, respectively. Orange and green represent the baseline and follow-up measurements, respectively. (A) Log(TMAO)—TMAO levels significantly decreased in the P+A and A groups (*p < 0.05), while no significant changes were observed in the P, and C groups. (B) Log(PCS)—PCS levels showed a significant reduction in the P+A and A groups (*p < 0.05), with stable levels in the P and C groups. (C) Log(IS)—IS levels were significantly reduced in the P+A and A groups (*p < 0.05). The P and C groups did not exhibit significant changes. (D) Log(PS)—PS decreased significantly in the P+A and A groups (*p < 0.05), with no significant change in the P and C groups. (E) Log(eGFR)—eGFR did not show significant changes in any groups, indicating stable kidney function over time. (F) Log(uACR)—UACR remained stable across all groups, with no significant differences between V0 and V1.