Protective Effect of Calcium Dobesilate on Induced AKI in Severely Burned Mice.

BACKGROUND: Early acute kidney injury (AKI) predicts a high mortality rate in severely burned patients. However, the pathophysiology of early AKI induced by severe burn has not been well-defined. This study was designed to examine the protective effects of calcium dobesilate (CaD) against severe burn-induced early AKI in mice and explore the mechanism. METHODS: The shaved backs of mice were immersed in 100°C water for 10 s to make severe burn (40% of the total body surface area). CD-57 male mice were randomly divided into sham, burn, burn + vehicle, and burn + CaD groups. Renal function, reactive oxygen species generation, tubular necrosis, and phosphorylation of mitogen-activated protein kinase, protein kinase B (Akt), and nuclear factor (NF)-κB were measured at 24 and 48 h after the burn. Renal histology, ELISA, qRT-PCR, and Western blotting were performed on the renal tissue of mice to examine the effects and mechanisms at 24 and 48 h after the burn. RESULTS: Tubular damage, cast formation, and elevations of serum creatinine, BUN, and renal tissue kidney injury molecule 1 levels were all observed in the burned mice, and these were all alleviated in the mice with CaD treatment. In addition, the levels of oxidation-reduction potential and malondialdehyde were decreased, while the activities of the endogenous antioxidative enzymes were increased in the kidney tissues from the mice after CaD treatment. Furthermore, the activities of Akt, p38, extracellular sign-regulated kinase, Jun N-terminal kinase, and NF-κB signaling were increased in the kidney of burned mice and normalized after CaD treatment. CONCLUSION: This study has established, for the first time, the protective effect of CaD against early AKI in severely burned mice. CaD may exert its protective effect through alleviating oxidative stress, apoptosis, and inflammation, as well as modulating some signaling pathways in the kidney.

First identification of PODXL nonsense mutations in autosomal dominant focal segmental glomerulosclerosis.

Recently, a novel heterozygous missense mutation c.T1421G (p. L474R) in the PODXL gene encoding podocalyxin was identified in an autosomal dominant focal segmental glomerulosclerosis (AD-FSGS) pedigree. However, this PODXL mutation appeared not to impair podocalyxin function, and it is necessary to identify new PODXL mutations and determine their causative role for FSGS. In the present study, we report the identification of a heterozygous nonsense PODXL mutation (c.C976T; p. Arg326X) in a Chinese pedigree featured by proteinuria and renal insufficiency with AD inheritance by whole exome sequencing (WES). Total mRNA and PODXL protein abundance were decreased in available peripheral blood cell samples of two affected patients undergoing hemodialysis, compared with those in healthy controls and hemodialysis controls without PODXL mutation. We identified another novel PODXL heterozygous nonsense mutation (c.C1133G; p.Ser378X) in a British-Indian pedigree of AD-FSGS by WES. In vitro study showed that, human embryonic kidney 293T cells transfected with the pEGFP-PODXL-Arg326X or pEGFP-PODXL-Ser378X plasmid expressed significantly lower mRNA and PODXL protein compared with cells transfected with the wild-type plasmid. Blocking nonsense-mediated mRNA decay (NMD) significantly restored the amount of mutant mRNA and PODXL proteins, which indicated that the pathogenic effect of PODXL nonsense mutations is likely due to NMD, resulting in podocalyxin deficiency. Functional consequences caused by the PODXL nonsense mutations were inferred by siRNA knockdown in cultured podocytes and podocalyxin down-regulation by siRNA resulted in decreased RhoA and ezrin activities, cell migration and stress fiber formation. Our results provided new data implicating heterozygous PODXL nonsense mutations in the development of FSGS.

The effects of Salvia przewalskii total phenolic acid extract on immune complex glomerulonephritis.

CONTEXT: Salvia przewalskii Maxim. (Lamiaceae) is a Chinese herbal medicine that has long been used for the treatment of cardiovascular disease. OBJECTIVE: The study investigated the therapeutic efficacy of S. przewalskii total phenolic acid extract (SPE) on immune complex glomerulonephritis (ICG) in rats. MATERIALS AND METHODS: Sixty-two Wistar rats were randomized into six groups. ICG was induced in all groups except normal control group. SPE was administered intragastrically at 24 h intervals for 40 consecutive days. Urine protein (UP), total serum protein (TSP), serum albumin (SA), serum cholesterol (SC) and serum urea nitrogen (SUN) were measured one day before, on day 20 and 40 after SPE administration. On day 40 after SPE administration, the kidneys were removed and prepared into pathologic sections. In addition, kidney wet mass was measured for calculating the kidney wet mass coefficient (KWMC). RESULTS: UP excretion was reduced significantly on day 20 after SPE administration in all three SPE groups as compared with that in medium group, and this effect was observable continuously until 40 days after SPE administration. Compared with medium group, TSP and SA were increased in all three SPE groups after 40 days treatment, while SC and SUN were decreased. KWMC was decreased significantly in 100 mg/kg SPE group after 40 days treatment compared with that in medium group. Histopathologic analyses showed that renal inflammatory infiltration and kidney intumesce were alleviated in all three SPE groups. CONCLUSIONS: SPE may be a potential therapeutic drug for glomerulonephritis.

Protective Effect of Salvia Przewalskii Extract on Puromycin-Induced Podocyte Injury.

BACKGROUND: To determine the effect of Salvia przewalskii extract (SPE) from total phenolic acids on puromycin aminonucleoside (PAN)-induced rat podocyte injury. METHODS: The rats were divided into groups that were treated with either PAN only or PAN followed by tacrolimus or SPE. We evaluated the effects of SPE on podocyte injury 5, 10, 15 and 21 days following treatment. RESULTS: (1) Proteinuria was observed starting on day 5 in all groups. The peak levels of proteinuria differed among the groups with tacrolimus and high-dose SPE, which significantly decreased proteinuria relative to the PAN and low- and medium-dose SPE groups. The proteinuria in each group decreased by day 15 and returned to a normal level by day 21. (2) H&E and PAS staining revealed no abnormality in glomerular morphology. With electron microscopy, we observed foot process effacement in the rats of all groups starting on day 5, but rats in the tacrolimus and high-dose SPE groups exhibited a lower degree. (3) IHC staining of nephrin and podocin revealed unaffected expression and better linear distributions in the high-dose SPE and tacrolimus groups. Western blot analysis confirmed that SPE could improve the expression of proteins. (4) The mRNA levels of nephrin and podocin in the tacrolimus and high-dose SPE groups were significantly higher than that in the others. CONCLUSION: In our study, we first demonstrated the ability of SPE to reduce proteinuria, preserve the morphology and structure of podocytes and retain the levels of slit diaphragm proteins on PAN-induced rat podocytes injury.

Risk factors for carotid artery distensibility in middle-aged and elderly hemodialysis patients.

BACKGROUND: Carotid intima media thickness (CIMT) and stiffness are taken as useful surrogate markers of atherosclerosis. In China, the number of elderly patients undergoing hemodialysis has increased year by year, with the increase of dialysis-related cardiovascular events. This study was undertaken to examine carotid stiffness in elderly hemodialysis patients by the ultrasound techniques in order to find out the possible risk factors. METHODS: From January 2006 to February 2010, a total of 87 patients (41 males and 46 females) treated with routine hemodialysis at the 97th Hospital of People's Liberation Army were enrolled in this study. The distensibility coefficient (DC) of the carotid artery was detected by Doppler ultrasonic diagnosis apparatus (Philips HBI5000, frequency 12 MHz) for evaluation of arterial stiffness. Serum albumin, total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL), triglyceride (TG), glucose, creatinine, calcium, phosphorus, and intact parathyroid hormone (iPTH) were examined with standard methods. The liner correlation and multiple stepwise regression analysis were used to find correlations between them. RESULTS: In this study, the systolic blood pressure was 153.33±25.98 mmHg, DBP 84.22± 10.39 mmHg, TC 4.39±1.05 mmol/L, TG 1.36±0.72 mmol/L, LDL 2.47±0.77 mmol/L, Cr 889.82± 207.38 Mmol/L, Glu 5.36±1.87 mmol/L, Ca I 2.00±2.19±0.21 mmol/L, and DC 13.39±5.32×10(-3)/kPa. DC was associated with age (r=-0.459, P<0.001), SBP (r=-0.527, P<0.001), and serum calcium (r=-0.273, P=0.011). The multiple stepwise regression analysis showed that SBP, age, increased serum calcium level, and diabetes were independent risk factors for decreasing DC. CONCLUSION: Systolic blood pressure, age, increased serum calcium level and diabetes in elderly hemodialysis patients are independent risk factors for increased carotid arterial stiffness.