Quercetin Ameliorates Diabetic Kidney Injury by Inhibiting Ferroptosis via Activating Nrf2/HO-1 Signaling Pathway.

Diabetic nephropathy (DN) is thought to be the major cause of end-stage renal disease. Due to its complicated pathogenesis and the low efficacy of DN treatment, a deep understanding of new etiological factors may be useful. Ferroptosis, a nonapoptotic form of cell death, is characterized by the accumulation of iron-dependent lipid peroxides to lethal levels. Ferroptosis-triggered renal tubular injury is reported to participate in the development of DN, and blocking ferroptosis might be an effective strategy to prevent the development of DN. Quercetin (QCT), a natural flavonoid that is present in a variety of fruits and vegetables, has been reported to ameliorate DN. However, its underlying nephroprotective mechanism is unclear. Herein, we explored the antiferroptosic effect of QCT and verified its nephroprotective effect using DN mice and high glucose (HG)-incubated renal tubular epithelial cell models. We found HG-induced abnormal activation of ferroptosis of renal tubular epithelial cells, and QCT treatment inhibited ferroptosis by downregulating the expression of transferrin receptor 1 (TFR-1) and upregulating the expression of glutathione peroxidase 4 (GPX4), ferritin heavy chain 1 (FTH-1), and the cystine/glutamate reverse antiporter solute carrier family 7 member (SLC7A11) in DN mice and HG-incubated HK-2 cells. Subsequently, both in vitro and in vivo results confirmed that QCT activated the NFE2-related factor 2 (Nrf2)/Heme oxygenase-1(HO-1) signaling pathway by increasing the levels of Nrf2 and HO-1. Therefore, this study supports that QCT inhibits the ferroptosis of renal tubular epithelial cells by regulating the Nrf2/HO-1 signaling pathway, providing a novel insight into the protective mechanism of QCT in DN treatment.

Down-regulation of Risa improves podocyte injury by enhancing autophagy in diabetic nephropathy.

BACKGROUND: LncRNA AK044604 (regulator of insulin sensitivity and autophagy, Risa) and autophagy-related factors Sirt1 and GSK3ß play important roles in diabetic nephropathy (DN). In this study, we sought to explore the effect of Risa on Sirt1/GSK3ß-induced podocyte injury. METHODS: Diabetic db/db mice received Risa-inhibition adeno-associated virus (AAV) via tail vein injection, and intraperitoneal injection of lithium chloride (LiCl). Blood, urine, and kidney tissue samples were collected and analyzed at different time points. Immortalized mouse podocyte cells (MPCs) were cultured and treated with Risa-inhibition lentivirus (LV), EX-527, and LiCl. MPCs were collected under different stimulations as noted. The effects of Risa on podocyte autophagy were examined by qRT-PCR, Western blotting analysis, transmission electron microscopy, Periodic Acid-Schiff staining, and immunofluorescence staining. RESULTS: Risa and activated GSK3ß were overexpressed, but Sirt1 was downregulated in DN mice and high glucose-treated MPCs (P < 0.001, db/m vs. db/db, NG or HM vs. HG), which was correlated with poor prognosis. Risa overexpression attenuated Sirt1-mediated downstream autophagy levels and aggravated podocyte injury by inhibiting the expression of Sirt1 (P < 0.001, db/m vs. db/db, NG or HM vs. HG). In contrast, Risa suppression enhanced Sirt1-induced autophagy and attenuated podocyte injury, which could be abrogated by EX-527 (P < 0.001, db/db + Risa-AAV vs. db/db, HG + Risa-LV vs. HG). Furthermore, LiCl treatment could restore GSK3ß-mediated autophagy of podocytes (P < 0.001, db/db + LiCl vs. db/db, HG + LiCl vs. HG), suggesting that Risa overexpression aggravated podocyte injury by decreasing autophagy. CONCLUSION: Risa could inhibit autophagy by regulating the Sirt1/GSK3ß axis, thereby aggravating podocyte injury in DN. Risa may serve as a therapeutic target for the treatment of DN.

High prevalence of hypovitaminosis D of patients with autoimmune rheumatic diseases in China.

We aimed to determine the prevalence of hypovitaminosis D in patients with autoimmune rheumatic diseases (ARDs) in China and its association with demographic characteristics of the patients. We recruited 384 patients in this cross-sectional study including 121 cases of systemic lupus erythematosus (SLE), 131 rheumatoid arthritis (RA), 102 spondyloarthritis (SpA) and 30 other ARDs. For each patient, demographic information was collected and serum concentration of 25OHD3 was measured by electrochemiluminescence immunoassay (ECLIA). The multivariate logistic regression model was used to investigate the association between vitamin D deficiency and patient characteristics. The mean serum vitamin D level of the 384 patients was 18.91 (8.12) ng/mL, and the median age was 37.33 (12.01) yrs. Among these patients, 222 (57.81%) and 127 (33.07%) were found to be vitamin D deficiency and insufficiency, respectively. From the disease perspective, the percentages of insufficiency and deficiency were as follow: 97.52% and 84.30% in SLE, 87.02% and 48.85% in RA, 88.24% and 40.20% in SpA, 90.89% and 57.81% in other ARDs patients. The causative factors for vitamin D deficiency included SLE per se (OR 12.54, P < 0.001) and high body mass index (BMI) (OR 1.88, P < 0.001). However, the seniors were less likely to have vitamin D deficiency (OR 0.95, P = 0.005). No correlation was disclosed between vitamin D deficiency and gender or disease duration. Hypovitaminosis D is highly prevalent among autoimmune rheumatic diseases population in China. The SLE per se and the obesity are the risk factors for vitamin D deficiency. Clinicians are advised to supplement vitamin D in these patients.

The Expression of Tristetraprolin and Its Relationship with Urinary Proteins in Patients with Diabetic Nephropathy.

OBJECTIVE: Tristetraprolin (TTP), also known as zinc finger protein 36, is an RNA binding protein that has a significant role in regulating the expression of mRNAs containing AU-rich elements. We postulated that TTP might regulate interleukin (IL)-6 and IL-18 expression in diabetes. This study aimed to test the hypothesis that the levels of TTP are correlated with nephropathy in patients with type 2 diabetes. METHODS: Eighty-seven patients (61.3±9.6 years old) who had been diagnosed with type 2 diabetes mellitus and 41 age and sex matched healthy control subjects were enrolled. The diabetes patients were classified into those without proteinuria, with microalbuminuria, and with clinical proteinuria groups according to the ratio of urinary excretion of albumin/creatinine (ACR). RESULTS: Serum and urinary levels of IL-6 and IL-18 were significantly elevated, but those of TTP were significantly decreased in patients with diabetes as compared with control subjects. In addition, serum and urinary levels of IL-6 and IL-18 were significantly higher, but those of TTP were significantly lower in patients with proteinuria than in patients without proteinuria or with microalbuminuria. There was a significant correlation between serum TTP and IL-6/IL-18 (correlation coefficients of -0.572 and -0.685, P < 0.05). CONCLUSION: These results show that diabetes with clinical proteinuria is accompanied by decreased urinary and serum level of TTP and increased levels of IL-6 and IL-18. Decreased TTP expression might occur prior to the increase in IL-6 and IL-18, and decrease of TTP might provide an earlier marker for glomerular dysfunction than IL-6 and IL-18.

Epidemiology and Clinical Correlates of AKI in Chinese Hospitalized Adults.

BACKGROUND AND OBJECTIVES: Comprehensive epidemiologic data on AKI are particularly lacking in Asian countries. This study sought to assess the epidemiology and clinical correlates of AKI among hospitalized adults in China. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This was a multicenter retrospective cohort study of 659,945 hospitalized adults from a wide range of clinical settings in nine regional central hospitals across China in 2013. AKI was defined and staged according to Kidney Disease Improving Global Outcomes criteria. The incidence of AKI in the cohort was estimated using a novel two-step approach with adjustment for the frequency of serum creatinine tests and other potential confounders. Risk factor profiles for hospital-acquired (HA) and community-acquired (CA) AKI were examined. The in-hospital outcomes of AKI, including mortality, renal recovery, length of stay, and daily cost, were assessed. RESULTS: The incidence of CA-AKI and HA-AKI was 2.5% and 9.1%, respectively, giving rise to an overall incidence of 11.6%. Although the risk profiles for CA-AKI and HA-AKI differed, preexisting CKD was a major risk factor for both, contributing to 20% of risk in CA-AKI and 12% of risk in HA-AKI. About 40% of AKI cases were possibly drug-related and 16% may have been induced by Chinese traditional medicines or remedies. The in-hospital mortality of AKI was 8.8%. The risk of in-hospital death was higher among patients with more severe AKI. Preexisting CKD and need for intensive care unit admission were associated with higher death risk in patients at any stage of AKI. Transiency of AKI did not modify the risk of in-hospital death. AKI was associated with longer length of stay and higher daily costs, even after adjustment for confounders. CONCLUSION: AKI is common in hospitalized adults in China and is associated with significantly higher in-hospital mortality and resource utilization.

Chinese herbal medicines for benign thyroid nodules in adults.

BACKGROUND: A thyroid nodule is a discrete lesion within the thyroid gland that might be palpable and is ultrasonographically distinct from the surrounding thyroid parenchyma. Thyroid nodules are more common as age increases and occur more frequently in women. Benign thyroid nodules often cause pressure symptoms and cosmetic complaints. In China and many other countries, doctors use Chinese herbal medicines (CHM) to treat thyroid nodules. OBJECTIVES: To assess the effects of Chinese herbal medicines in the treatment of benign thyroid nodules in adults. SEARCH METHODS: Review authors searched the following electronic databases: The Cochrane Library, MEDLINE, EMBASE, the Chinese Biomedical Literature Database (CBM), the China National Knowledge Infrastructure (CNKI), VIP information (a Chinese database), WANFANG Data (a Chinese database), the Chinese Conference Papers Database and the Chinese Dissertation Database (all searched up to April 2013). SELECTION CRITERIA: Randomised controlled trials comparing CHM or CHM plus levothyroxine versus levothyroxine, placebo or no treatment in adults with benign thyroid nodules. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data, assessed studies for risk of bias and evaluated overall study quality according to GRADE (Grading of Recommendations Assessment, Development and Evaluation), with differences resolved by consensus. MAIN RESULTS: We included one randomised trial involving 152 participants with a randomisation ratio of 2:1 (CHM vs no treatment). The trial applied adequate sequence generation; however, allocation concealment was unclear. Duration of treatment was three months, and follow-up six months. Our a priori defined outcomes of interest (i.e. nodule volume reduction ≥ 50%; pressure symptoms, cosmetic complaints or both; health-related quality of life; all-cause mortality; cancer occurrence; changes in number and size of thyroid nodules; changes in thyroid volume; and socioeconomic effects) were not investigated in the included study. Thyrotropin (TSH), thyroxine (T4) and tri-iodothyronine (T3) serum levels were normal in both groups before and after the trial was conducted. No adverse events were reported (low quality evidence). AUTHORS' CONCLUSIONS: Firm evidence cannot be found to support or refute the use of Chinese herbal medicines for benign thyroid nodules in adults.

Efficacy and safety of Abelmoschus manihot for primary glomerular disease: a prospective, multicenter randomized controlled clinical trial.

BACKGROUND: Abelmoschus manihot, a single medicament of traditional Chinese medicine, has been widely used to treat kidney disease. This is the first randomized controlled clinical trial to assess its efficacy and safety in patients with primary glomerular disease. STUDY DESIGN: Prospective, open-label, multicenter, randomized, controlled, clinical trial. SETTING & PARTICIPANTS: From May 2010 to October 2011, a total of 417 patients with biopsy-proven primary glomerular disease from 26 hospitals participated in the study. INTERVENTIONS: A manihot in the form of a huangkui capsule, 2.5 g, 3 times per day; losartan potassium, 50mg/d; or combined treatment, a huangkui capsule at 2.5 g 3 times per day, was combined with losartan potassium, 50mg/d. The duration of intervention was 24 weeks. OUTCOMES & MEASUREMENTS: The primary outcome was change in 24-hour proteinuria from baseline after treatment. Change in estimated glomerular filtration rate (eGFR) from baseline after treatment was a secondary outcome. The 24-hour proteinuria was measured every 4 weeks and eGFR was measured at 0, 4, 12, and 24 weeks. RESULTS: Mean baseline urine protein excretion was 1,045, 1,084, and 1,073 mg/d in the A manihot, losartan, and combined groups, respectively, and mean eGFR was 108, 106, and 106 mL/min/1.73 m2, respectively. After 24 weeks of treatment, mean changes in proteinuria were protein excretion of -508, -376, and -545 mg/d, respectively (P=0.003 for A manihot vs losartan and P<0.001 for the combined treatment vs losartan). Mean eGFR did not change significantly. The incidence of adverse reactions was not different among the 3 groups (P>0.05), and there were no severe adverse events in any group. LIMITATIONS: Results cannot be generalized to those with nephrotic syndrome or reduced eGFR. CONCLUSIONS: A manihot is a promising therapy for patients with primary kidney disease (chronic kidney disease stages 1-2) with moderate proteinuria.