The Highs and Lows of Potassium Intake in CKD-Does One Size Fit All?

The Role of Dietary Potassium in the Cardiovascular Protective Effects of Plant-Based Diets

Dietary intervention is an essential factor in managing a multitude of chronic health conditions such as cardiovascular and chronic kidney disease. In recent decades, there has been a host of research suggesting the potential benefit of plant-based diets in mitigating the health outcomes of these conditions. Plant-based diets are rich in vegetables and fruits, while limiting processed food and animal protein sources. The underlying physiological mechanism involves the interaction of several macronutrients and micronutrients such as plant protein, carbohydrates, and dietary potassium. Specifically, plant-based foods rich in potassium provide cardiorenal protective effects to include urinary alkalization and increased sodium excretion. These diets induce adaptive physiologic responses that improve kidney and cardiovascular hemodynamics and improve overall metabolic health. A shift toward consuming plant-based diets even in subjects with cardiorenal decrements may reduce their morbidity and mortality. Nonetheless, randomized controlled trials are needed to confirm the clinical benefits of plant-based diets.

Diet and Proteinuria: State of Art

Proteinuria is a broad term used to describe the pathological presence of proteins, including albumin, globulin, Bence-Jones protein, and mucoprotein in the urine. When persistent, proteinuria is a marker of kidney damage and represents a reliable predictor of the risk of progression of renal failure. Medical nutrition therapy is imperative for patients with proteinuria because it may slow the progression of renal disease. The aim of this review is to explore different nutritional approaches in the management of proteinuria and their influence on pathophysiological processes. As such, protein restriction is the main dietary intervention. Indeed, other management approaches are frequently used to reduce it regarding micro and macronutrients, but also the dietary style. Among these, the nutritional approach represents one of the most used and controversial interventions and the studies rarely take the form of randomized and controlled trials. With this work we aspire to analyze current clinical knowledge of how nutrition could influence proteinuria, potentially representing a useful tool in the management of proteinuric nephropathy.

Kir4.2 mediates proximal potassium effects on glutaminase activity and kidney injury

Inadequate potassium (K+) consumption correlates with increased mortality and poor cardiovascular outcomes. Potassium effects on blood pressure have been described previously; however, whether or not low K+ independently affects kidney disease progression remains unclear. Here, we demonstrate that dietary K+ deficiency causes direct kidney injury. Effects depend on reduced blood K+ and are kidney specific. In response to reduced K+, the channel Kir4.2 mediates altered proximal tubule (PT) basolateral K+ flux, causing intracellular acidosis and activation of the enzyme glutaminase and the ammoniagenesis pathway. Deletion of either Kir4.2 or glutaminase protects from low-K+ injury. Reduced K+ also mediates injury and fibrosis in a model of aldosteronism. These results demonstrate that the PT epithelium, like the distal nephron, is K+ sensitive, with reduced blood K+ causing direct PT injury. Kir4.2 and glutaminase are essential mediators of this injury process, and we identify their potential for future targeting in the treatment of chronic kidney disease.