Renal Medullary Overexpression of Sphingosine-1-Phosphate Receptor 1 Transgene Attenuates Deoxycorticosterone Acetate (DOCA)-Salt Hypertension.

BACKGROUND: Our previous studies showed that renal medullary sphingosine-1-phosphate receptor 1 (S1PR1) mediated sodium excretion, high salt intake increased S1PR1 level, deoxycorticosterone acetate (DOCA) blocked high salt-induced S1PR1 in the renal medulla, and that conditional knockout of S1PR1 in the collecting duct aggravated DOCA-salt hypertension. The present study tested the hypothesis that overexpression of S1PR1 transgene in the renal medulla attenuates the sodium retention and hypertension in DOCA-salt mouse model. METHODS: Male C57BL/6J mice received renal medullary transfection of control or S1PR1-expressing plasmids and then DOCA-salt treatment. Renal sodium excretion and arterial pressure were compared between control and S1PR1-overexpressed mice in response to high salt loading or pressure natriuresis. RESULTS: S1PR1-transfected mice showed significantly enhanced urinary sodium excretion in response to acute sodium loading (0.93 ± 0.27 in control vs. 4.72 ± 1.12 µmol/min/gKW in S1PR1-overexpressed mice, P < 0.05) and the pressure natriuresis (3.58 ± 1.77 vs. 9.52 ± 1.38, P < 0.05), less positive sodium balance in response to chronic high-salt intake (3.05 ± 0.39 vs. 1.65 ± 0.39 mmol/72 hr, P < 0.05), and consequently, the attenuation of DOCA-salt hypertension (134.2 ± 6.79 vs. 109.8 ± 3.54 mm Hg, P < 0.05). The αENaC protein amount in the renal medulla was not changed, however, the ßENaC was significantly decreased and the γENaC was significantly increased in S1PR1-overexpressed mice. The immunostaining showed apical membrane translocation of γENaC, while no change of αENaC and ßENaC in control mice, and that the apical membrane translocation of γENaC was blocked in S1PR1-treasffected mice. CONCLUSIONS: These results suggested that activation of S1PR1 in the renal medulla attenuates DOCA-induced sodium retention and salt-sensitive hypertension associated with inhibition of ENaC.

Genetic Knockout of Fatty Acid Amide Hydrolase Ameliorates Cisplatin-Induced Nephropathy in Mice.

Cisplatin is a potent first-line therapy for many solid malignancies, such as breast, ovarian, lung, testicular, and head and neck cancer. However, acute kidney injury (AKI) is a major dose-limiting toxicity in cisplatin therapy, which often hampers the continuation of cisplatin treatment. The endocannabinoid system, consisting of anandamide (AEA) and 2-arachidonoylglycerol and cannabinoid receptors, participates in different kidney diseases. Inhibition of fatty acid amide hydrolase (FAAH), the primary enzyme for the degradation of AEA and AEA-related N-acylethanolamines, elicits anti-inflammatory effects; however, little is known about its role in cisplatin nephrotoxicity. The current study tested the hypothesis that genetic deletion of Faah mitigates cisplatin-induced AKI. Male wild-type C57BL6 (WT) and Faah-/- mice were administered a single dose of intraperitoneal injection of cisplatin (30 mg/kg) and euthanatized 72 hours later. Faah-/- mice showed a reduction of cisplatin-induced blood urea nitrogen, plasma creatinine levels, kidney injury markers, and tubular damage in comparison with WT mice. The renal protection from Faah deletion was associated with enhanced tone of AEA-related N-acylethanolamines (palmitoylethanolamide and oleoylethanolamide), attenuated nuclear factor-κB/p65 activity, DNA damage markers p53 and p21, and decreased expression of the inflammatory cytokine interleukin-1ß, as well as infiltration of macrophages and leukocytes in the kidneys. Notably, a selective FAAH inhibitor (PF-04457845) did not interfere with or perturb the antitumor effects of cisplatin in two head and neck squamous cell carcinoma cell lines, HN30 and HN12. Our work highlights that FAAH inactivation prevents cisplatin-induced nephrotoxicity in mice and that targeting FAAH could provide a novel strategy to mitigate cisplatin-induced nephrotoxicity. SIGNIFICANCE STATEMENT: Mice lacking the Faah gene are protected from cisplatin-induced inflammation, DNA damage response, tubular damage, and kidney dysfunction. Inactivation of FAAH could be a potential strategy to mitigate cisplatin-induced nephrotoxicity.

Nephrotoxicity in cancer treatment: An update.

It has been estimated that nearly 80% of anticancer drug-treated patients receive potentially nephrotoxic drugs, while the kidneys play a central role in the excretion of anticancer drugs. Nephrotoxicity has long been a serious complication that hampers the effectiveness of cancer treatment and continues to influence both mortality and length of hospitalization among cancer patients exposed to either conventional cytotoxic agents or targeted therapies. Kidney injury arising from anticancer drugs tends to be associated with preexisting comorbidities, advanced cancer stage, and the use of concomitant non-chemotherapeutic nephrotoxic drugs. Despite the prevalence and impact of kidney injury on therapeutic outcomes, the field is sorely lacking in an understanding of the mechanisms driving cancer drug-induced renal pathophysiology, resulting in quite limited and largely ineffective management of anticancer drug-induced nephrotoxicity. Consequently, there is a clear imperative for understanding the basis for nephrotoxic manifestations of anticancer agents for the successful management of kidney injury by these drugs. This article provides an overview of current preclinical research on the nephrotoxicity of cancer treatments and highlights prospective approaches to mitigate cancer therapy-related renal toxicity.

Loss of sphingosine kinase 2 protects against cisplatin-induced kidney injury.

Cisplatin is an established chemotherapeutic drug for treatment of solid-organ cancers and is the primary drug used in the treatment of head and neck cancer; however, cisplatin-induced nephrotoxicity largely limits its clinical use. Inhibition of sphingosine kinase 2 (SphK2) has been demonstrated to alleviate various kidney diseases. Therefore, we hypothesized that inhibition of SphK2 could also protect against cisplatin-induced nephrotoxicity. Results from the present study showed that the SphK2 inhibitor ABC294640 or knockdown of SphK2 by siRNA blocked the cisplatin-induced increase of cellular injury markers (neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, and cleaved caspase-3) by Western blot analysis in HK-2 cells, a human renal tubular cell line. In addition, SphK2 inhibition blocked cisplatin-induced activation of NF-κB by Western blot analysis and immunostaining analysis. Furthermore, SphK2 inhibition suppressed cisplatin-induced increases of proinflammatory markers (NLR family pyrin domain containing 3, interleukin-1ß, and interleukin-6). Genetic deletion of the SphK2 gene in mice further confirmed that inhibition of SphK2 protected against cisplatin-induced kidney damage in vivo. Compared with wild-type mice, SphK2 knockout mice exhibited less renal dysfunction and reduced promotion of kidney injury markers, inflammatory factors, tubular morphology damage, and fibrotic staining. At the same time, the SphK2 inhibitor ABC294640 failed to interfere with the activity of cisplatin or radiation in two cell culture models of head and neck cancer. It is concluded that inhibition of Sphk2 protects against cisplatin-induced kidney injury. SphK2 may be used as a potential therapeutic target for the prevention or treatment of cisplatin-induced kidney injury.NEW & NOTEWORTHY The present study provides new findings that sphingosine kinase 2 (SphK2) is highly expressed in renal tubules, cisplatin treatment increases the expression of SphK2 in proximal tubular cells and kidneys, and inhibition of SphK2 alleviates cisplatin-induced kidney injury by suppressing the activation of NF-κB, production of inflammatory factors, and apoptosis. SphK2 may serve as a potential therapeutic target for the prevention or treatment of cisplatin-induced nephrotoxicity.

Inactivation of fatty acid amide hydrolase protects against ischemic reperfusion injury-induced renal fibrogenesis.

Although cannabinoid receptors (CB) are recognized as targets for renal fibrosis, the roles of endogenous cannabinoid anandamide (AEA) and its primary hydrolytic enzyme, fatty acid amide hydrolase (FAAH), in renal fibrogenesis remain unclear. The present study used a mouse model of post-ischemia-reperfusion renal injury (PIR) to test the hypothesis that FAAH participates in the renal fibrogenesis. Our results demonstrated that PIR showed upregulated expression of FAAH in renal proximal tubules, accompanied with decreased AEA levels in kidneys. Faah knockout mice recovered the reduced AEA levels and ameliorated PIR-triggered increases in blood urea nitrogen, plasma creatinine as well as renal profibrogenic markers and injuries. Correspondingly, a selective FAAH inhibitor, PF-04457845, inhibited the transforming growth factor-beta 1 (TGF-ß1)-induced profibrogenic markers in human proximal tubular cell line (HK-2 cells) and mouse primary cultured tubular cells. Knockdown of FAAH by siRNA in HK-2 cells had similar effects as PF-04457845. Tubular cells isolated from Faah-/- mice further validated the protection against TGF-ß1-induced damages. The CB 1 or CB2 receptor antagonist and exogenous FAAH metabolite arachidonic acid failed to reverse the protective effects of FAAH inactivation in HK-2 cells. However, a substrate-selective inhibitor of AEA-cyclooxygenase-2 (COX-2) pathway significantly suppressed the anti-profibrogenic actions of FAAH inhibition. Further, the AEA-COX-2 metabolite, prostamide E2 exerted anti-fibrogenesis effect. These findings suggest that FAAH activation and the consequent reduction of AEA contribute to the renal fibrogenesis, and that FAAH inhibition protects against fibrogenesis in renal cells independently of CB receptors via the AEA-COX-2 pathway by the recovery of reduced AEA.

Kidney-Targeted Delivery of Prolyl Hydroxylase Domain Protein 2 Small Interfering RNA with Nanoparticles Alleviated Renal Ischemia/Reperfusion Injury.

Inhibition of hypoxia-inducible factor-prolyl hydroxylase (PHD) has been shown to protect against various kidney diseases. However, there are controversial reports on the effect of PHD inhibition in renoprotection. The present study determined whether delivery of PHD2 small interfering RNA (siRNA) using an siRNA carrier, folic acid (FA)-decorated polyamidoamine dendrimer generation 5 (G5-FA), would mainly target kidneys and protect against renal ischemia/reperfusion injury (I/R). The renal I/R was generated by clipping the renal pedicle for 30 minutes in uninephrectomized mice. Mice were sacrificed 48 hours after I/R. Normal saline or G5-FA complexed with control or PHD2 siRNA was injected via tail vein 24 hours before ischemia. After the injection of near-infrared fluorescent dye-labeled G5-FA, the fluorescence was mainly detected in kidneys but not in other organs. The reduction of PHD2 mRNA and protein was only observed in kidneys but not in other organs after injection of PHD2-siRNA-G5-FA complex. The injection of PHD2-siRNA-G5-FA significantly alleviated renal I/R injury, as shown by the inhibition of increases in serum creatinine and blood urea nitrogen, the blockade of increases in kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin, and the improvement of histologic damage compared with mice treated with control siRNA. PHD2 siRNA can be delivered specifically into kidneys using G5-FA, and that local knockdown of PHD2 gene expression within the kidney alleviates renal I/R injury. Therefore, G5-FA is an efficient siRNA carrier to deliver siRNA into the kidney, and that local inhibition of PHD2 within the kidney may be a potential strategy for the management of acute I/R injury. SIGNIFICANCE STATEMENT: Folic acid (FA)-decorated polyamidoamine dendrimer generation 5 (G5-FA) was demonstrated to be an effective carrier to deliver small interfering RNA (siRNA) into kidneys. Delivery of prolyl hydroxylase domain protein 2 siRNA with G5-FA effectively protected the kidneys against the acute renal ischemia/reperfusion injury.

Collecting duct-specific knockout of sphingosine-1-phosphate receptor 1 aggravates DOCA-salt hypertension in mice.

OBJECTIVE: We have previously reported that renal medullary sphingosine-1-phosphate (S1P) regulates sodium excretion via the S1P type-1 receptor (S1PR1). As S1PR1 is predominantly expressed in collecting ducts (CD), the present study tested the hypothesis that the CD-S1PR1 pathway plays a critical role in sodium excretion and contributes to salt-sensitive hypertension. METHODS: CD-specific S1PR1 knockout mice were generated by crossing aquaporin-2-Cre mice with S1PR1-floxed mice. Renal sodium excretion and arterial pressure were compared between wild type and KO mice in response to high-salt challenges and treatment of deoxycorticosterone acetate (DOCA) salt. RESULTS: Protein levels of renal medullary S1PR1 were increased by 100% after high-salt intake, whereas DOCA treatment with high-salt intake blocked the increase of S1PR1 levels. Urinary sodium excretions in knockout mice were decreased by 60% compared with wild type mice after acute intravenous sodium loading (0.84 ±â€Š0.16 vs. 2.22 ±â€Š0.62 µmole/min per g kwt). The pressure natriuresis was impaired in knockout mice compared with wild type mice (4.32 ±â€Š1.04 vs. 8.73 ±â€Š0.19 µmole/min per g kwt). The chronic high-salt intake-induced positive sodium balance was enhanced in knockout mice compared with wild type mice (5.27 ±â€Š0.39 vs. 2.38 ±â€Š1.04 mmol/100 g BW per 24 h). After 10-day DOCA-salt treatment, knockout mice developed more severe hypertension than wild type mice (SBP 142 ±â€Š8 vs. 115 ±â€Š4 mmHg). CONCLUSION: The deletion of CD-S1PR1 reduced sodium excretion, promoted sodium retention, and accelerated DOCA-salt-induced salt-sensitive hypertension, suggesting that the CD-S1PR1 signaling is an important antihypertensive pathway by promoting sodium excretion and that impairment of renal medullary S1PR1 may represent a novel mechanism for salt-sensitive hypertension.

Long-Term Surveillance of Antibiotic Prescriptions and the Prevalence of Antimicrobial Resistance in Non-Fermenting Gram-Negative Bacilli.

The increasing emergence of multidrug-resistant (MDR) bacteria has been recognized as a public health threat worldwide. Hospitalized patients and outpatients are commonly infected by non-fermenting Gram-negative bacilli (NFGNB), particularly the Acinetobacter calcoaceticus-Acinetobacter baumannii complex (ACB) and Pseudomonas aeruginosa. Antimicrobial agents are critical for treating the nosocomial infections caused by NFGNB. The aim of this study was to assess antimicrobial resistance and the use of antimicrobial agents. The bacterial isolates of 638,152 specimens from both inpatients and outpatients, retrieved from 2001 to 2008 at a medical center in central Taiwan, were examined for their susceptibility to various antimicrobial agents, including cefepime, imipenem, ciprofloxacin, gentamicin, amikacin, meropenem, and levofloxacin. Administrated prescriptions of the monitored antibiotics were analyzed using the Taiwan National Health Insurance Research Database (NHIRD). Our results show that the defined daily doses (DDDs) for cefepime, imipenem, and ciprofloxacin increased with time, and a trend toward reduced antimicrobial sensitivities of both ACB and P. aeruginosa was noticeable. In conclusion, the antimicrobial sensitivities of ACB and P. aeruginosa were reduced with the increased use of antibiotics. Continuous surveillance of antibiotic prescriptions and the prevalence of emerging resistance in nosocomial infections is warranted.

Endoplasmic Reticulum Protein TXNDC5 Augments Myocardial Fibrosis by Facilitating Extracellular Matrix Protein Folding and Redox-Sensitive Cardiac Fibroblast Activation.

RATIONALE: Cardiac fibrosis plays a critical role in the pathogenesis of heart failure. Excessive accumulation of extracellular matrix (ECM) resulting from cardiac fibrosis impairs cardiac contractile function and increases arrhythmogenicity. Current treatment options for cardiac fibrosis, however, are limited, and there is a clear need to identify novel mediators of cardiac fibrosis to facilitate the development of better therapeutics. Exploiting coexpression gene network analysis on RNA sequencing data from failing human heart, we identified TXNDC5 (thioredoxin domain containing 5), a cardiac fibroblast (CF)-enriched endoplasmic reticulum protein, as a potential novel mediator of cardiac fibrosis, and we completed experiments to test this hypothesis directly. OBJECTIVE: The objective of this study was to determine the functional role of TXNDC5 in the pathogenesis of cardiac fibrosis. METHODS AND RESULTS: RNA sequencing and Western blot analyses revealed that TXNDC5 mRNA and protein were highly upregulated in failing human left ventricles and in hypertrophied/failing mouse left ventricle. In addition, cardiac TXNDC5 mRNA expression levels were positively correlated with those of transcripts encoding transforming growth factor ß1 and ECM proteins in vivo. TXNDC5 mRNA and protein were increased in human CF (hCF) under transforming growth factor ß1 stimulation in vitro. Knockdown of TXNDC5 attenuated transforming growth factor ß1-induced hCF activation and ECM protein upregulation independent of SMAD3 (SMAD family member 3), whereas increasing expression of TXNDC5 triggered hCF activation and proliferation and increased ECM protein production. Further experiments showed that TXNDC5, a protein disulfide isomerase, facilitated ECM protein folding and that depletion of TXNDC5 led to ECM protein misfolding and degradation in CF. In addition, TXNDC5 promotes hCF activation and proliferation by enhancing c-Jun N-terminal kinase activity via increased reactive oxygen species, derived from NAD(P)H oxidase 4. Transforming growth factor ß1-induced TXNDC5 upregulation in hCF was dependent on endoplasmic reticulum stress and activating transcription factor 6-mediated transcriptional control. Targeted disruption of Txndc5 in mice (Txndc5-/-) revealed protective effects against isoproterenol-induced cardiac hypertrophy, reduced fibrosis (by ≈70%), and markedly improved left ventricle function; post-isoproterenol left ventricular ejection fraction was 59.1±1.5 versus 40.1±2.5 (P<0.001) in Txndc5-/- versus wild-type mice, respectively. CONCLUSIONS: The endoplasmic reticulum protein TXNDC5 promotes cardiac fibrosis by facilitating ECM protein folding and CF activation via redox-sensitive c-Jun N-terminal kinase signaling. Loss of TXNDC5 protects against ß agonist-induced cardiac fibrosis and contractile dysfunction. Targeting TXNDC5, therefore, could be a powerful new therapeutic approach to mitigate excessive cardiac fibrosis, thereby improving cardiac function and outcomes in patients with heart failure.

Analyses of antibacterial activity and cell compatibility of titanium coated with a Zr-C-N film.

OBJECTIVE: The purpose of this study was to verify the antibacterial performance and cell proliferation activity of zirconium (Zr)-carbon (C)-nitride (N) coatings on commercially pure titanium (Ti) with different C contents. MATERIALS AND METHODS: Reactive nitrogen gas (N(2)) with and without acetylene (C(2)H(2)) was activated by Zr plasma in a cathodic-arc evaporation system to deposit either a zirconium nitride (ZrN) or a Zr-C-N coating onto Ti plates. The bacterial activity of the coatings was evaluated against Staphylococcus aureus with the aid of SYTO9 nucleic acid staining and scanning electron microscopy (SEM). Cell compatibility, mRNA expression, and morphology related to human gingival fibroblasts (HGFs) on the coated samples were also determined by using the MTT assay, reverse transcriptase-polymerase chain reaction, and SEM. RESULTS: The Zr-C-N coating with the highest C content (21.7 at%) exhibited the lowest bacterial preservation (P<0.001). Biological responses including proliferation, gene expression, and attachment of HGF cells to ZrN and Zr-C-N coatings were comparable to those of the uncoated Ti plate. CONCLUSIONS: High-C-content Zr-C-N coatings not only provide short-term antibacterial activity against S. aureus but are also biocompatible with HGF cells.

Inhibition of enterovirus 71 infections and viral IRES activity by Fructus gardeniae and geniposide.

Fructus gardeniae has long been used by traditional Chinese medical practitioners for its anti-inflammatory, anti-oxidant, anti-tumor and anti-hyperlipidemic characteristics. Here we describe our finding that F. gardeniae greatly reduces anti-enterovirus 71 (EV71) activity, resulting in significant decreases in EV71 virus yields, EV71 infections, and internal ribosome entry site activity. We also found that geniposide, a primary F. gardeniae component, inhibited both EV71 replication and viral IRES activity. Our data suggest the presence of a mechanism that blocks viral protein translation. According to our findings, F. gardeniae and geniposide deserve a closer look as potential chemopreventive agents against EV71 infections.

Simple organic molecules bearing a 3,4-ethylenedioxythiophene linker for efficient dye-sensitized solar cells.

3,4-Ethylenedioxythiophene and bis[2-(2-methoxyethoxy)ethoxy]thiophene bridged donor-acceptor molecules for dye-sensitized solar cells have been synthesized, one of which achieved a solar-to-energy conversion efficiency of 7.3%, compared to 7.7% optimized for N719 dye.

Use of acupressure to improve gastrointestinal motility in women after trans-abdominal hysterectomy.

The purpose of this study was to evaluate the effectiveness of acupressure on gastrointestinal (GI) motility in women after trans-abdominal hysterectomy (TAH). Patients were randomly assigned into two groups of 21 and 20 patients each. The experimental group received acupressure for 3 minutes at each of three meridian points: Neiguan (PC-6), Zusanli (ST-36) and Sanyinjiao (SP-6). The control group received 3 minutes of acupressure on sham points. Acupressure was performed twice a day. A questionnaire was used to determine patients' satisfaction prior to and after afternoon acupressure. GI contractions were measured with a multifunctional stethoscope before and after acupressure. Acupressure of these three meridian points significantly (p < 0.05) increased GI motility in the experimental group, but there was little change in the control group (p > 0.05). Our conclusions are that non-invasive acupressure of these meridian points can significantly improve GI motility and can be incorporated into the technical curriculum and clinical education program of nursing schools. Patients and their family members can be taught to continue this procedure at home to enhance GI motility in patients who have undergone TAH.