Dietary phosphate supplementation delays the onset of iron deficiency anemia and affects iron status in rats

Hyperphosphatemia increases inflammation to exacerbate anemia and skeletal muscle wasting independently of FGF23-FGFR4 signaling

Elevations in plasma phosphate concentrations (hyperphosphatemia) occur in chronic kidney disease (CKD), in certain genetic disorders, and following the intake of a phosphate-rich diet. Whether hyperphosphatemia and/or associated changes in metabolic regulators, including elevations of fibroblast growth factor 23 (FGF23) directly contribute to specific complications of CKD is uncertain. Here, we report that similar to patients with CKD, mice with adenine-induced CKD develop inflammation, anemia, and skeletal muscle wasting. These complications are also observed in mice fed high phosphate diet even without CKD. Ablation of pathologic FGF23-FGFR4 signaling did not protect mice on an increased phosphate diet or mice with adenine-induced CKD from these sequelae. However, low phosphate diet ameliorated anemia and skeletal muscle wasting in a genetic mouse model of CKD. Our mechanistic in vitro studies indicate that phosphate elevations induce inflammatory signaling and increase hepcidin expression in hepatocytes, a potential causative link between hyperphosphatemia, anemia, and skeletal muscle dysfunction. Our study suggests that high phosphate intake, as caused by the consumption of processed food, may have harmful effects irrespective of pre-existing kidney injury, supporting not only the clinical utility of treating hyperphosphatemia in CKD patients but also arguing for limiting phosphate intake in healthy individuals.

The effect of ethion on erythrocyte deformability

Organophosphates cause increased oxidative susceptibility of erythrocytes and changes in erythrocyte deformability ability. We aim is to investigate the role of ethion (ETH) on erythrocyte deformability and to show whether vinpocetine (VIN) and carnosine (CAR) are protective against these changes. The study was performed on Sprague Dawley rats with an average weight of 220 ± 40 g and 4-5 months old. Six experimental groups were composed of 10 rats per group. Hematological parameters, erythrocyte deformability, % hemolysis, 2.3bisphosphoglycerate, and methemoglobin values were measured in blood samples taken after 10 days of drug application. Erythrocyte count, hemoglobin amount, hematocrit value, serum potassium level, and erythrocyte deformability decreased in the ETH group. Leukocyte, platelet count, methemoglobin amount, and % hemolysis rates increased in the ETH group. The values of the ETH + CAR and ETH + VIN groups were found to be closer to the control group. In organophosphate poisoning such as ETH, the deformability ability of erythrocytes exposed to constant oxidative stress is changing, and therefore their ability to deliver oxygen to tissues is negatively affected. VIN and CAR may have improve on erythrocyte deformability in this type of intoxication.

Dietary phosphate exacerbates intestinal inflammation in experimental colitis

The recent widespread consumption of Western diets and food additives worldwide is associated with excessive inorganic phosphate intake. However, researchers have known little about the impact of dietary phosphate intake on the development of inflammatory bowel disease to date. In this study, we investigated the effects of dietary phosphate on intestinal inflammation in experimental colitis. Sprague-Dawley rats were fed different phosphate diets (0.5%, 1.0% and 1.5% phosphate) with or without dextran sulfate sodium. For in vitro study, the effects of phosphate on proinflammatory cytokine induction and reactive oxygen species production in RAW264.7 macrophage were examined. Dietary phosphate exacerbated intestinal inflammation in experimental colitis in a dose-dependent manner, as assessed by the clinical disease activity score, colon length, and histology. Furthermore, the high phosphate diet increased myeloperoxidase activity and proinflammatory cytokine mRNA expression through the activation of nuclear factor κB in the inflamed colon. In addition, high phosphate loading in RAW264.7 cells directly enhanced reactive oxygen species production and proinflammatory cytokine gene expression. Our results demonstrated that the high phosphate diet exacerbated intestinal inflammation in experimental colitis. These findings have important therapeutic implications for inflammatory bowel disease patients.