Calcification In Rat Model Research Articles

Pharmacological TNAP inhibition efficiently inhibits arterial media calcification in a warfarin rat model but deserves careful consideration of potential physiological bone formation/mineralization impairment.

Arterial media calcification is frequently seen in elderly and patients with chronic kidney disease (CKD), diabetes and osteoporosis. Pyrophosphate is a well-known calcification inhibitor that binds to nascent hydroxyapatite crystals and prevents further incorporation of inorganic phosphate into these crystals. However, the enzyme tissue-nonspecific alkaline phosphatase (TNAP), which is expressed in calcified arteries, degrades extracellular pyrophosphate into phosphate ions, by which pyrophosphate loses its ability to block vascular calcification. Here, we aimed to evaluate whether pharmacological TNAP inhibition is able to prevent the development of arterial calcification in a rat model of warfarin-induced vascular calcification. To investigate the effect of the pharmacological TNAP inhibitor SBI-425 on vascular calcification and bone metabolism, a 0.30% warfarin rat model was used. Warfarin exposure resulted in distinct calcification in the aorta and peripheral arteries. Daily administration of the TNAP inhibitor SBI-425 (10mg/kg/day) for 7weeks significantly reduced vascular calcification as indicated by a significant decrease in calcium content in the aorta (vehicle 3.84±0.64mg calcium/g wet tissue vs TNAP inhibitor 0.70±0.23mg calcium/g wet tissue) and peripheral arteries and a distinct reduction in area % calcification on Von Kossa stained aortic sections as compared to vehicle. Administration of SBI-425 resulted in decreased bone formation rate and mineral apposition rate, and increased osteoid maturation time and this without significant changes in osteoclast- and eroded perimeter. Administration of TNAP inhibitor SBI-425 significantly reduced the calcification in the aorta and peripheral arteries of a rat model of warfarin-induced vascular calcification. However, suppression of TNAP activity should be limited in order to maintain adequate physiological bone mineralization.

Site-specific chelation therapy with EDTA-loaded albumin nanoparticles reverses arterial calcification in a rat model of chronic kidney disease

Medial arterial calcification (MAC) is a common outcome in diabetes and chronic kidney disease (CKD). It occurs as linear mineral deposits along the degraded elastin lamellae and is responsible for increased aortic stiffness and subsequent cardiovascular events. Current treatments for calcification, particularly in CKD, are predominantly focused on regulating the mineral disturbance and other risk factors. Ethylene diamine tetraacetic acid (EDTA), a chelating agent, can resorb mineral deposits, but the systemic delivery of EDTA may cause side effects such as hypocalcemia and bone resorption. We have developed elastin antibody conjugated albumin nanoparticles that target only degraded elastin in vasculature while sparing healthy tissues. In this study, we tested a targeted nanoparticle-based EDTA chelation therapy to reverse CKD-associated MAC. Renal failure was induced in Sprague-Dawley rats by a high adenine diet supplemented by high P and Ca for 28 days that led to MAC. Intravenous delivery of DiR dye-loaded nanoparticles confirmed targeting to vascular degraded elastin and calcification sites within 24 hours. Next, EDTA-loaded albumin nanoparticles conjugated with an anti-elastin antibody were intravenously injected twice a week for two weeks. The targeted nanoparticles delivered EDTA at the site of vascular calcification and reversed mineral deposits without any untoward effects. Systemic EDTA injections or blank nanoparticles were ineffective in reversing MAC. Reversal of calcification seems to be stable as it did not return after the treatment was stopped for an additional four weeks. Targeted EDTA chelation therapy successfully reversed calcification in this adenine rat model of CKD. We consider that targeted NP therapy will provide an attractive option to reverse calcification and has a high potential for clinical translation.

Tanshinone II A attenuates atherosclerotic calcification in rat model by inhibition of oxidative stress

Aim We have previously proved that oxidized low-density lipoprotein (oxLDL), a proatherogenic lipoprotein, plays a pivotal role in the development of atherosclerotic calcification (AC). The present study was performed to investigate whether tanshinone II A (TS II A), an anti-oxidant which has been shown to inhibit in vitro oxidation of LDL, has the effects to inhibit AC in rat model and by which, if any, mechanisms. Methods Rat AC model was induced by excessive vitamin D 2 (VD) and high cholesterol diet (HCD), which was proven to be successful histopathologically and biochemically. Results Administration of AC rats with TS II A (35, 70 mg/kg) dose-dependently attenuated the AC pathological changes, meanwhile reduced the vessel contents of lipid and calcium. However, TS II A had no effects on serum levels of lipids, calcium and 25-OH VD. Further studies revealed that TS II A decreased serum concentration of oxLDL, reduced the superoxide anion production and malondialdehyde (MDA) in vessel. In addition, TS II A increased vessel Cu/Zn SOD activity, upregulated vessel mRNA and protein expression of Cu/Zn SOD. Conclusion The results suggested that TS II A significantly attenuated the AC in rat model, which might be attributed to its inhibition of oxLDL production independent of the serum levels of lipids, calcium and 25-OH VD, and that increasing of Cu/Zn SOD activity as well as mRNA and protein expression by TS II A might protect LDL against oxidation induced by superoxide anion in vessel.