Effect of calcium citrate in calcium carbonate nanoparticles on HK-2 cells in acidic environment

Abstract

Metabolic acidosis exerts several cellular and tissue dysfunctions, such as increases mineral bone and protein degradation, induces inflammation, oxidative stress and cell death. These complications lead to multiple organ failure, including chronic kidney disease. Sodium bicarbonate and Shohl’s solution are commonly used to treat metabolic acidosis. However, these agents cause frequent gastrointestinal adverse effects. Hence, we invented the new calcium carbonate nanoparticles to use as a drug delivery system for carrying citrate to renal cell which we hypothesize to reduce adverse effects of metabolic acidosis. We studied the physical characteristics and pharmacological effects of calcium citrate nanoparticle (Cacit) and calcium citrate in calcium carbonate nanoparticles (CCN) on HK-2 cells in acidic environment on the aspect of cytotoxicity, ROS and bicarbonate generation, pH modification and cell death. Our results showed that the Cacit and CCN has spherical molecule with diameter between 50-70 and 60-80 nm, respectively. Cacit has surface charge about -16.1 mV and CCN has -13.0 mV. Citrate content in Cacit and CCN was approximately 31% and 25%, and both nanoparticles was uptake into the cell freely in normal and acidic condition. Cacit and CCN had very low cytotoxicity at the concentration up to 1 mg/ml. Pharmacological characterization revealed that both Cacit and CCN contained antioxidant properties which was appeared to be more potent than standard drug sodium citrate (Nacit). Cacit and CCN treatment did not alkalinize extracellular pH, or extracellular and intracellular bicarbonate concentration. We found that Cacit and CCN treatment ameliorated acidosis-induced cell death similar to Nacit. In conclusion, Cacit and CCN were a potential medication to use as an adjuvant therapy with standard drug in chronic acidosis. Further study is required to elucidate the systemic pharmacological effects of these nanoparticles in animal.