Gut microbiome alterations at acute myeloid leukemia diagnosis are associated with muscle weakness and anorexia

Abstract

The gut microbiota makes critical contributions to host homeostasis, and its role in the treatment of acute myeloid leukemia (AML) has attracted attention. We investigated whether the gut microbiome is affected by AML, and whether such changes are associated with hallmarks of cachexia. Biological samples and clinical data were collected from 30 antibiotic- free AML patients at diagnosis and matched volunteers (1:1) in a multicenter, cross-sectional, prospective study. The composition and functional potential of the fecal microbiota were analyzed using shotgun metagenomics. Fecal, blood, and urinary metabolomics analyses were performed. AML patients displayed muscle weakness, anorexia, signs of altered gut function, and glycemic disorders. The composition of the fecal microbiota differed between patients with AML and control subjects, with an increase in oral bacteria. Alterations in bacterial functions and fecal metabolome support an altered redox status in the gut microbiota, which may contribute to the altered redox status observed in patients with AML. Eubacterium eligens, reduced 3-fold in AML patients, was strongly correlated with muscle strength and citrulline, a marker of enterocyte mass and function. Blautia and Parabacteroides, increased in patients with AML, were correlated with anorexia. Several bacterial taxa and metabolites (e.g., Blautia, Prevotella, phenylacetate, and hippurate) previously associated with glycemic disorders were altered. Our work revealed important perturbations in the gut microbiome of AML patients at diagnosis, which are associated with muscle strength, altered redox status, and anorexia. These findings pave the way for future mechanistic work to explore the function and therapeutic potential of the bacteria identified in this study.

Figure 1.

The composition and function of the gut microbiota of patients with acute myeloid leukemia differ from those of control subjects (results of the metagenomics sequencing). (A) Principal component analysis (PCA) at the genus level (metagenomics results). Permutational multivariate analysis of variance (PERMANOVA): R = 3.1%, P<0.01. (B) Contribution of disease, body mass index, muscle strength, hemoglobin, sex, and age to the variance in the PCA at the genus level (PERMANOVA results). ^**P<0.01; ^$P=0.055. (C) Significantly changed taxa at the lowest taxonomical level from metagenomics results. Mann-Whitney U-tests with a false discovery rate correction were applied. Data are expressed as median with interquartile range. *q value <0.1. (D) Oral species and obligate anaerobe genera. ^**P<0.01; ^*P<0.05. (E) PCA on bacterial EC (Enzyme Commission) enzyme functions. PERMANOVA: R²=2.1%, not significant. (F) Significantly changed bacterial EC enzyme functions in control subjects (represented in gray) and patients with acute myeloid leukemia (represented in orange). N=30. PCA: principal component analysis; BMI: body mass index; CT: controls; AML: acute myeloid leukemia.

Figure 2.

Acute myeloid leukemia patients display anorexia, muscle weakness and glycemic disorders compared to control subjects. (A) C-reactive protein, albumin and modified Glasgow prognostic score in controls and patients with acute myeloid leukemia (AML). (B) Appetite (SNAQ score) and muscle strength in controls and AML. (C) Glycemia (fasted), insulin and HOMA-IR2 in controls and patients with AML. (A, B) N=30. (C) Fasted glycemia, N=20; insulin and HOMA-IR2: N=19. AML patients are represented in orange, controls in gray. Variables that are normally distributed are expressed as mean (standard deviation) and are tested using a Student t test or a Welch t test. Variables that are non-normally distributed are expressed as median (interquartile range) and are tested by a Mann-Whitney U-test. Differences in modified Glasgow prognostic scores are tested using a χ test. ^*P<0.05; ^**P<0.01; ^***P<0.001. CT: control subjects; AML: acute myeloid leukemia patients; CRP: C-reactive protein; mGPS: modified Glasgow prognostic score; SNAQ: Simplified Nutritional Appetite Questionnaire; HOMA-IR2: second homeostatic model assessment for insulin resistance.

Figure 3.

Acute myeloid leukemia patients display inflammation and signs of gut dysfunction compared to control subjects. (A) Inflammatory markers in control subjects and patients with acute myeloid leukemia (AML). (B) Metabolic markers in controls and AML patients. (C) Gut function markers in controls and AML patients. Variables that are normally distributed are expressed as mean (standard deviation) and are tested using a Student t test or a Welch t test. Variables that are non-normally distributed are expressed as median (interquartile range) and are tested by a Mann-Whitney U-test. AML patients are represented in orange and control subjects in gray. ^*P<0.05; ^**P<0.01; ^***P<0.001; ^****P<0.0001. CT: control subjects; AML: acute myeloid leukemia patients; IL6: interleukin-6; IL8: interleukin-8; IL10: interleukin-10; MCP1: monocyte chemoattractant protein 1; TNFα: tumor necrosis factor alpha-1; TGFβ1: transforming growth factor beta-1; GDF15: growth differentiation factor 15; FGF21: fibroblast growth factor 21; LBP: lipopolysaccharide-binding protein.

Figure 4.

Univariate analyses pinpoint differences in the relative concentrations of identified metabolites in the three analyzed compartments (feces, blood and urine). In the bubble plot. bubble size depicts concentration fold change based on the group median. Colored bubbles correspond to affected metabolites. Light and dark orange are used for metabolites increased in the acute myeloid leukemia (AML) group (with P<0.05 and a false discovery rate (FDR)-corrected q-value <0.1). Light and dark gray are used for metabolites decreased in the AML group (P<0.05 and FDR-corrected q-value <0.1). Uncol-ored bubbles represent unaffected metabolites. N=30 per group.

Figure 5.

The top altered bacteria correlate with several blood and fecal metabolites. Spearman correlations. Metabolites with at least one correlation with an altered taxon are present. Microbial taxa are ordered by fold change. ‘+’ symbolizes P<0.05 and ‘*’ symbolizes a false discovery rate-corrected q-value <0.1. AML: acute myeloid leukemia.

Figure 6.

Top altered bacteria correlate with clinical, dietary, inflammatory, and metabolic parameters in control subjects and patients with acute myeloid leukemia. Spearman correlations. ‘+’ symbolizes P<0.05 and ‘*’ symbolizes a false discovery rate-corrected q-value <0.1. Parameters with at least one correlation with an altered taxon are present. Microbial taxa are ordered by fold change. BMI: body mass index; WBCC: white blood cell count; appetite (SNAQ score); CRP: C-reactive protein; mGPS: modified Glasgow prognostic score; HOMA-IR2: second homeostatic model assessment for insulin resistance; IL6: interleukin-6; IL8: interleukin-8; IL10: interleukin-10; MCP1: monocyte chemoattractant protein 1; TNFα: tumor necrosis factor alpha; TGFβ1: transforming growth factor beta-1; GDF15: growth differentiation factor 15; FGF21: fibroblast growth factor 21; LBP: lipopolysaccha-ride-binding protein; AML: acute myeloid leukemia.

Figure 7.

Summary of altered bacteria and functions in acute myeloid leukemia patients and their associations with hallmarks of cachexia and altered host redox status. Full two-way arrows represent significant correlations, dashed two-way arrows signify associations and simple way arrows indicate contributions based on literature. Created with BioRender.com. GDF15: growth differentiation factor 15.