Long Term High Protein Diet Feeding Alters the Microbiome and Increases Intestinal Permeability, Systemic Inflammation and Kidney Injury in Mice.

SCOPE: This study evaluates the effects of a chronic high protein diet (HPD) on kidney injury, intestinal permeability and gut microbiota perturbations in a mouse model. METHOD AND RESULTS: Mice are fed a diet containing either 20% or 52% energy from protein for 24 weeks; protein displaced an equivalent amount of wheat starch. The HPD does not alter glycemic control or body weight. The HPD induces kidney injury as evidenced by increase in albuminuria, urinary kidney injury molecule-1, blood urea nitrogen, urinary isoprostanes and renal cortical NF-κB p65 gene expression. HPD decreases intestinal occludin gene expression, increases plasma endotoxin and plasma monocyte chemoattractant protein-1, indicating intestinal leakiness and systemic inflammation. Cecal microbial analysis reveals that HPD feeding does not alter alpha diversity; however, it does alter beta diversity, indicating an altered microbial community structure with HPD feeding. Predicted metagenome pathway analysis demonstrates a reduction in branched-chain amino acid synthesis and an increase of the urea cycle with consumption of a HPD. CONCLUSION: These results demonstrate that long term HPD consumption in mice causes albuminuria, systemic inflammation, increase in gastrointestinal permeability and is associated with gut microbiome remodeling with an increase in the urea cycle pathway, which may contribute to renal injury.

Mitochondrial Dysfunction and Signaling in Diabetic Kidney Disease: Oxidative Stress and Beyond.

The kidneys are highly metabolic organs that produce vast quantities of adenosine triphosphate via oxidative phosphorylation and, as such, contain many mitochondria. Although mitochondrial reactive oxygen species are involved in many physiological processes in the kidneys, there is a plethora of evidence to suggest that excessive production may be a pathologic mediator of many chronic kidney diseases, including diabetic kidney disease. Despite this, results from clinical testing of antioxidant therapies have been generally underwhelming. However, given the many roles of mitochondria in cellular functioning, pathways other than reactive oxygen species production may prevail as pathologic mediators in diabetic kidney disease. Accordingly, in this review, mitochondrial dysfunction in a broader context is discussed, specifically focusing on mitochondrial respiration and oxygen consumption, intrarenal hypoxia, oxidative stress, mitochondrial uncoupling, and networking.