Effects of Maqui Supplementation on Gut Microbiota, Inflammation, and Oxidative Stress in Patients With Chronic Kidney Disease

Effects of Maqui Supplementation on Gut Microbiota, Inflammation, and Oxidative Stress in Patients With Chronic Kidney Disease: A Gender-Based Approach

Chronic kidney disease (CKD) is a highly prevalent condition in Chile and worldwide and is associated with a substantial burden of morbidity, particularly cardiovascular morbidity. In the early stages of CKD, treatment aims to preserve kidney function and slow the progression of associated complications. Several conditions have been reported in association with CKD, including impaired antioxidant capacity, inflammation, and alterations in the gut microbiota (GM), which contribute, among other complications, to the loss of kidney function and cardiovascular damage. In the search for therapeutic approaches to modulate CKD-related complications, there is growing interest in complementary non-pharmacological interventions, including nutritional strategies within the "Food as Medicine" concept. In this context, maqui remains largely unexplored in CKD. Maqui contains phenolic compounds with bioactive properties and strong antioxidant activity, which have also been associated with anticancer, antimicrobial, and anti-inflammatory effects, as well as inhibition of enzymes involved in metabolic syndrome, making this fruit of particular interest for human health. To date, no studies have evaluated the therapeutic potential of maqui in relation to oxidative stress, inflammation, gut microbiota, and CKD progression, or whether these biomarkers and the response to maqui supplementation differ according to biological sex.

To evaluate the effects of maqui supplementation in men and women on the modulation of gut microbiota, inflammatory parameters, and oxidative stress in patients with stage 3 and 4 chronic kidney disease.

A longitudinal, randomized, double-blind clinical trial will be conducted in patients with CKD recruited from healthcare centers in the Metropolitan Region of Santiago, Chile. Participants will receive either a dietary supplement containing dried maqui extract in powder form, equivalent to 200 mg of Delphinol, or placebo for three months. At baseline and after three months of intervention, gut microbiota composition, uremic toxins, inflammatory and oxidative stress markers (plasma antioxidant capacity, urinary polyphenols, IL-6, high-sensitivity C-reactive protein [hs-CRP], NGAL, and uremic toxins), parameters of CKD progression, and anthropometric and dietary parameters will be assessed.

Inclusion Criteria:

• Men and women.
• Age between 40 and 75 years.
• Normal weight or overweight nutritional status.
• Regular attendance at healthcare follow-up visits.
• CKD stage 3-4 (eGFR 59-15)

Exclusion Criteria:

• Acute kidney injury within the three months preceding the intervention.
• Inflammatory or infectious disease within the three months preceding the intervention.
• Current smoking.
• Use of oral anticoagulant therapy.
• Pregnancy.
• Current use of dietary supplements containing maqui.
• Cancer.
• Current antibiotic treatment or antibiotic use within the two weeks preceding the intervention.