oxalates and Vascular-Calcification

Cardiovascular disease is the most common cause of morbidity and mortality in patients with ESRD. In addition to phosphate overload, oxalate, a common uremic toxin, is also involved in vascular calcification in patients with ESRD. The present study investigated the role and mechanism of hyperoxalemia in vascular calcification in mice with uremia.. A uremic atherosclerosis (UA) model was established by left renal excision and right renal electrocoagulation in apoE-/- mice to investigate the relationship between oxalate loading and vascular calcification. After 12 weeks, serum and vascular levels of oxalate, vascular calcification, inflammatory factors (TNF-α and IL-6), oxidative stress markers (malondialdehyde [MDA], and advanced oxidation protein products [AOPP]) were assessed in UA mice. The oral oxalate-degrading microbe Oxalobacter formigenes (O. formigenes) was used to evaluate the effect of a reduction in oxalate levels on vascular calcification. The mechanism underlying the effect of oxalate loading on vascular calcification was assessed in cultured human aortic endothelial cells (HAECs) and human aortic smooth muscle cells (HASMCs).. Serum oxalate levels were significantly increased in UA mice. Compared to the control mice, UA mice developed more areas of aortic calcification and showed significant increases in aortic oxalate levels and serum levels of oxidative stress markers and inflammatory factors. The correlation analysis showed that serum oxalate levels were positively correlated with the vascular oxalate levels and serum MDA, AOPP, and TNF-α levels, and negatively correlated with superoxide dismutase activity. The O. formigenes intervention decreased serum and vascular oxalate levels, while did not improve vascular calcification significantly. In addition, systemic inflammation and oxidative stress were also improved in the O. formigenes group. In vitro, high concentrations of oxalate dose-dependently increased oxidative stress and inflammatory factor expression in HAECs, but not in HASMCs.. Our results indicated that hyperoxalemia led to the systemic inflammation and the activation of oxidative stress. The reduction in oxalate levels by O. formigenes might be a promising treatment for the prevention of oxalate deposition in calcified areas of patients with ESRD.

Topics: Animals; Atherosclerosis; Cell Line; Disease Models, Animal; Endothelial Cells; Humans; Male; Mice; Oxalates; Oxidative Stress; Renal Insufficiency, Chronic; Uremia; Vascular Calcification

Chaga mushrooms are widely used in folk remedies and in alternative medicine. Contrary to many beneficial effects, its adverse effect is rarely reported. We here report a case of end-stage renal disease after long-term taking Chaga mushroom. A 49-year-old Korean man with end stage renal disease (ESRD) was transferred to our hospital. Review of kidney biopsy finding was consistent with chronic tubulointerstitial nephritis with oxalate crystal deposits and drug history revealed long-term exposure to Chaga mushroom powder due to intractable atopic dermatitis. We suspected the association between Chaga mushroom and oxalate nephropathy, and measured the oxalate content of remained Chaga mushroom. The Chaga mushroom had extremely high oxalate content (14.2/100 g). Estimated daily oxalate intake of our case was 2 times for four years and 5 times for one year higher than that of usual diet. Chaga mushroom is a potential risk factor of chronic kidney disease considering high oxalate content. Nephrologist should consider oxalate nephropathy in ESRD patients exposed to Chaga mushrooms.

Topics: Humans; Inonotus; Kidney; Kidney Failure, Chronic; Male; Middle Aged; Oxalates; Risk Factors; Tomography, X-Ray Computed; Vascular Calcification