Previous studies have suggested the benefits of physical exercise for patients on dialysis. We conducted the Exercise Introduction to Enhance Performance in Dialysis trial, a 6-month randomized, multicenter trial to test whether a simple, personalized walking exercise program at home, managed by dialysis staff, improves functional status in adult patients on dialysis. The main study outcomes included change in physical performance at 6 months, assessed by the 6-minute walking test and the five times sit-to-stand test, and in quality of life, assessed by the Kidney Disease Quality of Life Short Form (KDQOL-SF) questionnaire. We randomized 296 patients to normal physical activity (control; n=145) or walking exercise (n=151); 227 patients (exercise n=104; control n=123) repeated the 6-month evaluations. The distance covered during the 6-minute walking test improved in the exercise group (mean distance±SD: baseline, 328±96 m; 6 months, 367±113 m) but not in the control group (baseline, 321±107 m; 6 months, 324±116 m; P<0.001 between groups). Similarly, the five times sit-to-stand test time improved in the exercise group (mean time±SD: baseline, 20.5±6.0 seconds; 6 months, 18.2±5.7 seconds) but not in the control group (baseline, 20.9±5.8 seconds; 6 months, 20.2±6.4 seconds; P=0.001 between groups). The cognitive function score (P=0.04) and quality of social interaction score (P=0.01) in the kidney disease component of the KDQOL-SF improved significantly in the exercise arm compared with the control arm. Hence, a simple, personalized, home-based, low-intensity exercise program managed by dialysis staff may improve physical performance and quality of life in patients on dialysis.

We examined the effect of insulin and plasma amino acid concentrations on leucine kinetics in 15 healthy volunteers (age 22 +/- 2 yr) using the euglycemic insulin clamp technique and an infusion of [1-14C]leucine. Four different experimental conditions were examined: (a) study one, high insulin with reduced plasma amino acid concentrations; (b) study two, high insulin with maintenance of basal plasma amino acid concentrations; (c) study three, high insulin with elevated plasma amino acid concentrations; and (d) study four, basal insulin with elevated plasma amino acid concentrations. Data were analyzed using both the plasma leucine and alpha-ketoisocaproate (the alpha-ketoacid of leucine) specific activities. In study one total leucine flux, leucine oxidation, and nonoxidative leucine disposal (an index of whole body protein synthesis) all decreased (P less than 0.01) regardless of the isotope model utilized. In study two leucine flux did not change, while leucine oxidation increased (P less than 0.01) and nonoxidative leucine disposal was maintained at the basal rate; endogenous leucine flux (an index of whole body protein degradation) decreased (P less than 0.01). In study three total leucine flux, leucine oxidation, and nonoxidative leucine disposal all increased significantly (P less than 0.01). In study four total leucine flux, leucine oxidation, and nonoxidative leucine disposal all increased (P less than 0.001), while endogenous leucine flux decreased (P less than 0.001). We conclude that: (a) hyperinsulinemia alone decreases plasma leucine concentration and inhibits endogenous leucine flux (protein breakdown), leucine oxidation, and nonoxidative leucine disposal (protein synthesis); (b) hyperaminoacidemia, whether in combination with hyperinsulinemia or with maintained basal insulin levels decreases endogenous leucine flux and stimulates both leucine oxidation and nonoxidative leucine disposal.

Heavy metals are extensively used in agriculture and industrial applications such as production of pesticides, batteries, alloys, and textile dyes. Prolonged, intensive or excessive exposure can induce related systemic disorders. Kidney is a target organ in heavy metal toxicity for its capacity to filter, reabsorb and concentrate divalent ions. The extent and the expression of renal damage depends on the species of metals, the dose, and the time of exposure. Almost always acute kidney impairment differs from chronic renal failure in its mechanism and in the magnitude of the outcomes. As a result, clinical features and treatment algorithm are also different. Heavy metals in plasma exist in an ionized form, that is toxic and leads to acute toxicity and a bound, inert form when metal is conjugated with metallothionein and are then delivered to the liver and possible causing the kidney chronic damage. Treatment regimens include chelation therapy, supportive care, decontamination procedures and renal replacement therapies. This review adds specific considerations to kidney impairment due to the most common heavy metal exposures and its treatment.

CKD frequently leads to chronic cardiac dysfunction. This complex relationship has been termed as cardiorenal syndrome type 4 or cardio-renal link. Despite numerous studies and reviews focused on the pathophysiology and therapy of this syndrome, the role of arterial stiffness has been frequently overlooked. In this regard, several pathogenic factors, including uremic toxins (i.e., uric acid, phosphates, endothelin-1, advanced glycation end-products, and asymmetric dimethylarginine), can be involved. Their effect on the arterial wall, direct or mediated by chronic inflammation and oxidative stress, results in arterial stiffening and decreased vascular compliance. The increase in aortic stiffness results in increased cardiac workload and reduced coronary artery perfusion pressure that, in turn, may lead to microvascular cardiac ischemia. Conversely, reduced arterial stiffness has been associated with increased survival. Several approaches can be considered to reduce vascular stiffness and improve vascular function in patients with CKD. This review primarily discusses current understanding of the mechanisms concerning uremic toxins, arterial stiffening, and impaired cardiac function, and the therapeutic options to reduce arterial stiffness in patients with CKD.