Metataxonomics and Metabolomics Profiles in Metabolic Dysfunction-Associated Fatty Liver Disease Patients on a "Navelina" Orange-Enriched Diet

Abstract

Background/objectives: Metabolic dysfunction-associated fatty liver disease (MAFLD) is currently the most common cause of chronic liver disease. Systemic inflammatory status and peripheral metabolic symptoms in the clinical picture have an impact on gut commensal bacteria.

Methods: Our designed clinical trial was based on a cohort of patients with MAFLD whose diet included the daily consumption of 400 g of "Navelina" oranges for 28 days, compared with a control group of patients with the same pathologic conditions whose diet did not include the consumption of oranges and other foods containing similar nutrients/micronutrients. We used 16S metataxonomics and GC/MS analyses to identify taxa and urine/fecal VOCs, respectively.

Results: A set of micronutrients from the diet were inspected, and some specific fatty acids were identified as the main contributors in terms of cluster sample separation. Metataxonomics and metabolomics profiles were obtained, and a stringent statistical approach allowed for the identification of significant taxa/VOCs, which emerged from pairwise group comparisons in both fecal and urine samples.

Conclusions: In conclusion, a set of taxa/VOCs can be directly referred to as a marker of dysbiosis status and other comorbidities that, together, make up the pathologic burden associated with MAFLD. The investigated variables can be a target of therapeutic strategies.

Keywords: 16S metataxonomics; fecal metabolomics; metabolic dysfunction-associated fatty liver disease; orange diet.

Figure 1

(A) The a priori and a posterior DAPCs based on anthropometric and micronutrients/vitamins varying in dietary regimens. (B) The minimum in the BIC curve indicated the number of identified clusters in the a priori analysis. (C) A posterior DAPC analysis based on known group belonging. (D) Loading plot with variables that most contributed to the analysis. (E) Assign plot; proportions of successful reassignments: heat colors represent membership probabilities (red = 1, white = 0, orange/yellow = non completely succeeded reassignment) and blue crosses represent the DAPC prior cluster.

Figure 2

(A) DAPC based on genus relative abundances. (B): DAPC loading plots reporting most impacting genera over the arbitrary threshold of 0.02.

Figure 3

Group comparison based on the Welch test joined with the fold change analyses. Panel (A): Pairwise comparison between T2 orange-treated and T2 control. Panel (B): Pairwise comparison between T2 orange-treated versus controls. For both the panels, increased (red) and decreased (violet) in orange-administered samples at T2 genera were compared with T2 control (Panel (A)) and control samples at T1 (Panel (B)), respectively.

Figure 4

Urine and fecal VOC DAPC plot. Matrices of ppm concentration values from each identified VOC have been merged and used as inputs for the DAPC. (A): DAPC plot with used eigenvalues. (B): DAPC loading plot with most contributing VOCs above the 0.01 arbitrary threshold. Urine and fecal VOC names have been marked by red and blue fonts, respectively.