Astragalus polysaccharides attenuate rat aortic endothelial senescence via regulation of the SIRT-1/p53 signaling pathway.

BACKGROUND: Astragalus polysaccharides (APS) have been verified to have antioxidative and antiaging activities in the mouse liver and brain. However, the effect of APS on aortic endothelial senescence in old rats and its underlying mechanism are currently unclear. Here, we aimed to elucidate the effects of APS on rat aortic endothelial oxidative stress and senescence in vitro and in vivo and investigate the potential molecular targets. METHODS: Twenty-month-old natural aging male rats were treated with APS (200 mg/kg, 400 mg/kg, 800 mg/kg daily) for 3 months. Serum parameters were tested using corresponding assay kits. Aortic morphology was observed by staining with hematoxylin and eosin (H&E) and Verhoeff Van Gieson (VVG). Aging-related protein levels were evaluated using immunofluorescence and western blot analysis. Primary rat aortic endothelial cells (RAECs) were isolated by tissue explant method. RAEC mitochondrial function was evaluated by the mitochondrial membrane potential (MMP) measured with the fluorescent lipophilic cationic dye JC­1. Intracellular total antioxidant capacity (T-AOC) was detected by a commercial kit. Cellular senescence was assessed using senescence-associated-ß-galactosidase (SA-ß-Gal) staining. RESULTS: Treatment of APS for three months was found to lessen aortic wall thickness, renovate vascular elastic tissue, improve vascular endothelial function, and reduce oxidative stress levels in 20-month-old rats. Primary mechanism analysis showed that APS treatment enhanced Sirtuin 1 (SIRT-1) protein expression and decreased the levels of the aging marker proteins p53, p21 and p16 in rat aortic tissue. Furthermore, APS abated hydrogen peroxide (H2O2)-induced cell senescence and restored H2O2-induced impairment of the MMP and T-AOC in RAECs. Similarly, APS increased SIRT-1 and decreased p53, p21 and p16 protein levels in senescent RAECs isolated from old rats. Knockdown of SIRT-1 diminished the protective effect of APS against H2O2-induced RAEC senescence and T-AOC loss, increased the levels of the downstream proteins p53 and p21, and abolished the inhibitory effect of APS on the expression of these proteins in RAECs. CONCLUSION: APS may reduce rat aortic endothelial oxidative stress and senescence via the SIRT-1/p53 signaling pathway.

Low BMI, blood calcium and vitamin D, kyphosis time, and outdoor activity time are independent risk factors for osteoporosis in postmenopausal women.

Aim: To explore the risk factors of osteoporosis in postmenopausal women in China. Method: This study collected all patient data from January 2014 to December 2015. Basic information and questionnaires were collected from 524 postmenopausal women in Sanya and Hainan Province. The questionnaire was administered to the enrolled participants by endocrinologists. Biochemical parameters were measured using fasting blood samples, and bone density was measured by dual energy X-ray absorptiometry at the department of radiology of Hainan hospital, PLA General Hospital. Participants with an R-value of ≤-2.5 were diagnosed with osteoporosis. After deleting missing values for each factor, 334 participants were divided into the osteoporosis (n=35) and non-osteoporosis (n=299) groups according to the R-values. Results: The participants had a median age of 60.8 years (range: 44-94 years). Among the 334 postmenopausal women included in this study, 35 (10.5%) were diagnosed with osteoporosis. Univariate analysis showed statistically significant differences in age, BMI, type of work, alkaline phosphatase, years of smoking, blood calcium levels, kyphosis, fracture, and asthma between the two groups (P<0.05). In addition, multivariate logistic analysis showed that age (odds ratio [OR]: 1.185, 95% confidence interval [CI]: 1.085-1.293, P<0.001) and kyphosis times (OR:1.468, 95% CI: 1.076-2.001, P=0.015) were positively correlated with postmenopausal osteoporosis, whereas BMI (OR: 0.717, 95% CI: 0.617-0.832, P<0.001), blood calcium levels (OR: 0.920, 95% CI: 0.854-0.991, P=0.027), vitamin D levels (OR: 0.787, 95% CI: 0.674-0.918, P=0.002), and outdoor activity time (OR: 0.556, 95% CI: 0.338-0.915, P=0.021) were negatively correlated with postmenopausal osteoporosis. Conclusion: Low BMI, blood calcium and vitamin D levels, kyphosis time, and outdoor activity time are independent risk factors for osteoporosis in postmenopausal women.

Occurrence and depositional history of organochlorine pesticides in the sediments of the Zayandehrud River in the arid region of Central Iran.

In this study, surface sediments along the Zayandehrud River (14 samples), and two dated core sediments (46 samples) from small artificial urban lakes at the middle section of the Zayandehrud River in the Gavkhooni basin in the central arid regions of Iran were analyzed for residual levels of 20 organochlorine pesticide (OCP) compounds. Total OCP concentrations ranged from 0.1 to 50.1 ng g-1 dry weight and from 1.9 to 51.5 ng g-1 dry weight in surface and core sediments, respectively. Dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) were found to be the predominant OCPs in these sediments. The calculated metabolic and isomeric ratios confirmed the aged nature of residual dichlorodiphenyltrichloroethane (DDT) in sediments. Moreover, the isomeric ratios indicated the aged nature of technical HCH (hexachlorocyclohexane), while the contribution of γ- HCH (lindane) as a main source has increased, especially in the last two decades. Past usage, as well as current usage of endosulfan technical mixture in the Gavkhooni basin, has been found in the last four decades. Analyses of sedimentary cores, as natural archives, have shown the successful ban on the use of organochlorine pesticides (especially DDT) in the Gavkhooni basin, and to some extent, in the central plateau of Iran. In general, it can be concluded that natural factors (i.e., floods and wet years) lead to soil leachate and play an essential role in remobilization and transfer of residual OCPs from soil to inland aquatic ecosystems in the Gavkhooni basin, which is an arid region.

[Establishment of senescent cell model in primary rat aortic endothelial cells].

Objective To establish senescent models in rat aortic endothelial cells (RAECs) induced by high glucose (HG), angiotensin II (AngII), hydrogen peroxide and palmitic acid (PA), and compare the senescence-induced effects of these factors. Methods Primary RAECs were extracted from two-month-old male Wistar rats by issue explant method and identified by CD31 immunofluorescence cytochemistry. RAECs were treated separately by 30 mmol/L (HG), 10 µmol/L AngII, 100 umol/L hydrogen peroxide (H2O2) and 0.5 mmol/L PA. Twenty-four hours later, senescence-associated ß-galactosidase (SA-ß-gal) staining was used to evaluate the senescent state. Real-time quantitative PCR was used to investigate mRNA expression level of senescence-related gene P16. Western blot analysis was performed to determine protein expression levels of P16, P21 and P53. Immunofluorescence cytochemistry was used to detect the expression of P16 protein in cells. The cell viability of RAECs was tested via CCK-8 assay. Results Compared with the control group, positive rate of SA-ß-gal staining in each treatment group increased, especially in H2O2 and PA groups. And mRNA expression level of P16 increased in all four groups. P16 and P21 proteins had high expression in AngII, H2O2 and PA groups, most obviously in H2O2 group. P16 immunofluorescence expression level was enhanced in all groups. The cell viability in HG and AngII groups was similar with the control group, while H2O2 and PA groups had low cell viability. Conclusion The aging mode of RAECs is successfully established by HG, AngII, H2O2 or PA treatment, and H2O2 treatment shows the strongest effect.

Melatonin attenuates renal fibrosis in diabetic mice by activating the AMPK/PGC1α signaling pathway and rescuing mitochondrial function.

Mitochondrial homeostasis is a highly regulated process that serves a critical role in the maintenance of renal structure and function. The growing interest in the field of mitochondrial homeostasis promises to provide more information regarding the mechanisms involved in diabetic renal fibrosis, and aid in the development of novel strategies to combat the disease. In the present study, the effects of melatonin on renal damage in mice with diabetes were evaluated and the underlying mechanisms were investigated. Cellular apoptosis was determined using TUNEL assay and western blotting. Mitochondrial function was measured using fluorescence assay and western blotting. The results indicated that diabetic renal fibrosis was associated with 5'adenosine monophosphate­activated protein kinase (AMPK) downregulation. However, melatonin administration rescued AMPK activity, reduced diabetic renal fibrosis, alleviated glomerular apoptosis and preserved kidney function. The functional experiments demonstrated that melatonin­induced AMPK activation enhanced peroxisome proliferator­activated receptor γ coactivator 1­α (PGC1α) expression, sustained mitochondrial function and blocked mitochondrial apoptosis, leading to protection of the glomerulus against glucotoxicity. However, loss of AMPK and PGC1α negated the protective effects of melatonin on mitochondrial homeostasis, glomerular survival and diabetic renal fibrosis. In summary, the present study revealed that melatonin rescued impaired mitochondrial function and reduced glomerular apoptosis in the context of diabetic renal fibrosis by activating the AMPK/PGC1α pathway.

Edwardsiella piscicida virulence effector trxlp promotes the NLRC4 inflammasome activation during infection.

Edwardsiella piscicida is an important pathogenic bacterium that causes hemorrhagic septicemia in fish. This bacterium could activate NLRC4 and NLRP3 inflammasomes via type III secretion system (T3SS), and inhibit NLRP3 inflammasome via type VI secretion system (T6SS) effector during infection in macrophages. However, the roles of other virulence factors in regulating inflammasome activation during E. piscicida infection remain poorly understood. In this study, we focused on clarification the role of ETAE_RS10155, a thioredoxin-like protein (Trxlp), during bacterial infection in macrophages. We found that mutation of this gene barely influences the bacteria growth and infection capability. Interestingly, the inflammasome activation was reduced in Δtrxlp-infected macrophages, compared with wild-type E. piscicida did. Moreover, Trxlp mainly promotes the NLRC4, but not NLRP3 inflammasome activation during E. piscicida infection. Finally, Trxlp-mediated NLRC4 inflammasome activation is crucial for host surveillance in vivo. Taken together, our results clarify the complex and contextual role of bacterial virulence effector in modulating inflammasome activation, and offer new insights into the warfare between the fish bacterial weapons and host innate immunological surveillance.

Vitamins for Prevention of Contrast-induced Acute Kidney Injury: A Systematic Review and Trial Sequential Analysis.

BACKGROUND: To date, universally accepted preventive measures for contrast-induced acute kidney injury (CI-AKI) do not exist, and they warrant further research. OBJECTIVE: The purpose of this study was to evaluate the efficacy of vitamins, including vitamin C and E, for prevention of CI-AKI. METHODS: We electronically searched the MEDLINE, EMBASE, and Cochrane databases. The outcome of interest was the incidence of CI-AKI. RESULTS: A total of 19 studies were included in this meta-analysis. Pooled analysis showed that vitamin C plus saline [relative risk (RR) = 0.63, 95% confidence interval (CI) 0.49-0.82, p = 0.0005] and vitamin E plus saline (RR = 0.39, 95% CI 0.24-0.62, p < 0.0001) significantly reduced the incidence of CI-AKI compared to saline alone. The effect of vitamin C plus saline was further confirmed by trial sequential analysis (TSA). However, TSA indicated that more trials are required to confirm the efficacy of vitamin E plus saline. There was no significant difference in preventing CI-AKI between vitamin C and N-acetylcysteine (NAC) (RR = 0.90, 95% CI 0.47-1.71, p = 0.75), between vitamin C plus NAC and saline (RR = 0.62, 95% CI 0.30-1.30, p =  0.20), as well as between vitamin C plus NAC and NAC (RR = 0.97, 95% CI 0.49-1.92, p = 0.93). CONCLUSIONS: Vitamin C plus saline administration is effective at reducing the risk of CI-AKI. Evidence for the use of vitamin E plus saline in this context is encouraging, but more trials are required. Furthermore, this meta-analysis and TSA indicated insufficient power to draw a definitive conclusion on the effect of vitamin C plus NAC, versus saline or NAC alone, which needs to be explored further.

L-Carnitine Ameliorates the Decrease of Aquaporin 2 Levels in Rats with Cisplatin-Induced Kidney Injury.

BACKGROUND: It has been found that L-carnitine ameliorated cisplatin-induced acute kidney injury (AKI) in rats. However, the detailed role of L-carnitine in improving the renal urinary concentration function in cisplatin-induced AKI is not fully understood. METHODS: In this study, 30 Sprague-Dawley rats were divided randomly into 5 groups: control, cisplatin (CIS), L-carnitine (CAR), L-carnitine plus cisplatin (CAR + CIS), and cisplatin plus L-carnitine (CIS + CAR) groups. Cisplatin (7 mg/kg) and L-carnitine (300 mg/kg) were injected intraperitoneally. Urine (24 h) and blood samples were collected to analyze renal urinary concentrating function. Immunoblotting, confocal laser microscopy, and enzyme-linked immunosorbent assays were used to assess the level and localization of the water channel aquaporin (AQP) 2, and levels of stimulatory G protein α subunit (GSα protein), arginine vasopressin (AVP) receptor 2, adenylyl cyclase and serum AVP. RESULTS: Renal urinary concentrating function was improved by L-carnitine in rats with cisplatin-induced AKI. AQP2 expression, which decreased after cisplatin treatment, was improved by L-carnitine in different regions of the kidney. Moreover, our data indicated that L-carnitine could increase AQP2 accumulation at the apical plasma membranes of the renal-collecting ducts. Finally, intervention with L-carnitine effectively improved the expression of AQP2 upstream signaling proteins, such as GSα protein, adenylyl cyclase, and serum AVP levels in rats with cisplatin-induced AKI. CONCLUSION: L-carnitine resolves the cisplatin-induced urinary concentration defect, which may occur by increasing AVP/cyclic adenosine monophosphate/AQP2 levels, indicating the potential use of L-carnitine to ameliorate the renal urinary concentration effect in cancer patients treated with cisplatin.

The human glucagon-like peptide-1 analogue liraglutide regulates pancreatic beta-cell proliferation and apoptosis via an AMPK/mTOR/P70S6K signaling pathway.

Glucagon-like peptide-1 (GLP-1), an effective therapeutic agent for the treatment of diabetes, has been proven to protect pancreatic beta cells through many pathways. Recent evidence demonstrates that AMP-activated protein kinase (AMPK), as a metabolic regulator, coordinates beta-cell protein synthesis through regulation of the mammalian target of rapamycin (mTOR) signaling pathway. The purpose of the present study was to explore whether liraglutide, a human GLP-1 analogue, protects beta cells via AMPK/mTOR signaling. We evaluated INS-1 beta-cell line proliferation using the Cell Counting Kit-8, and examined the effect of GLP-1 on cellular ATP levels using an ATP assay kit. mTOR pathway protein expression levels were tested by Western blotting and glucolipotoxicity-induced cell apoptosis was evaluated by flow cytometry. Liraglutide increased beta-cell viability at an optimum concentration of 100 nmol/L in the presence of 11.1 or 30 mmol/L glucose. Liraglutide (100 nmol/L) activated mTOR and its downstream effectors, 70-kDa ribosomal protein S6 kinase and eIF4E-binding protein-1, in INS-1 cells. This effect was abated by pathway blockers: the AMPK activator AICAR and the mTOR inhibitor rapamycin. Furthermore, the effect of liraglutide on beta-cell proliferation was inhibited by AICAR and rapamycin. Liraglutide increased cellular ATP levels. In addition, liraglutide protected beta cells from glucolipotoxicity-induced apoptosis. This response was also prevented by rapamycin treatment. These results suggest that the enhancement of beta-cell proliferation by that GLP-1 receptor agonist liraglutide is mediated, at least in part, by AMPK/mTOR signaling. Liraglutide also prevents beta-cell glucolipotoxicity by activating mTOR.