Diet has been associated with several
metabolic diseases and may impact immunity. Increased consumption of meals with high
oxalate content may stimulate urinary
calcium oxalate (CaOx) crystals, which are precursors to CaOx
kidney stones. We previously reported that CaOx stone formers have decreased monocyte cellular bioenergetics compared to healthy participants and
oxalate reduces monocyte metabolism and redox status in vitro. The purpose of this study was to investigate whether dietary
oxalate loading impacts monocyte cellular bioenergetics, mitochondrial complex activity, and inflammatory signaling in humans. Healthy participants (n = 40; 31.1 ± 1.3 years) with a BMI of 24.9 ± 0.6 kg/m2 consumed a controlled low
oxalate diet for 3 days before drinking a blended preparation of fruits and vegetables containing a large amount of
oxalate. Blood and urine were collected before (pre-
oxalate) and for 5 h after the
oxalate load to assess urinary
oxalate levels, monocyte cellular bioenergetics and mitochondrial complex activity, and plasma
cytokine/
chemokine levels. Urinary
oxalate levels significantly increased in post-
oxalate samples compared to pre-
oxalate samples. Monocyte cellular bioenergetics, mitochondrial complex I activity, and plasma
cytokine and
chemokine levels were altered to varying degrees within the study cohort. We demonstrate for the first time that dietary
oxalate loading may impact monocyte metabolism and immune response in a cohort of healthy adults, but these response are variable. Further studies are warranted to understand
oxalate mediated mechanisms on circulating monocytes and how this potentially influences CaOx
kidney stone formation.
Clinical Trial Registration: ClinicalTrials.gov, identifier NCT03877276.