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Summary This study was conducted to determine the phenotypic and genotypic characteristics of multidrug-resistant (MDR) avian pathogenic Escherichia coli (APEC). A total of 54 MDR APEC were divided into 23 serotypes, and O78 (16.6%) was the most frequently observed. The MDR APEC carried β-lactamase–encoding genes (38.9%), integrons (61.6%), plasmid-mediated quinolone–resistant genes (20.4%), tetracycline-resistant genes (79.6%), sulfonamide-resistant genes (40.7%), and chloramphenicol-resistant genes (18.5%). Phylogenetic group D (44.4%), which is associated with extraintestinal strains, was the most frequently observed, but all MDR APEC, including groups A, B1, and B2, carried one or more virulence genes. This study analyzed the phenotypic and genotypic characterization in MDR APEC isolated from broilers with colibacillosis in Korea. It is important to monitor the occurrence of resistance genes in APEC. These bacteria may pose serious therapeutic problems when treating sick broilers. The MDR strains carried by animals and birds can enter the human food chain through the consumption of meat or other animal or poultry products.

Oxidative stress is one of the principal causes of hypoxia-induced kidney injury. The ceria nanoparticle (CNP) is known to exhibit free radical scavenger and catalytic activities. When zirconia is attached to CNPs (CZNPs), the ceria atom tends to remain in a Ce3+ form and its efficacy as a free radical scavenger thus increases. We determined the effectiveness of CNP and CZNP antioxidant activities against hypoxia-induced acute kidney injury (AKI) and observed that these nanoparticles suppress the apoptosis of hypoxic HK-2 cells by restoring autophagy flux and alleviating mitochondrial damage. In vivo experiments revealed that CZNPs effectively attenuate hypoxia-induced AKI by preserving renal structures and glomerulus function. These nanoparticles can successfully diffuse into HK-2 cells and effectively counteract reactive oxygen species (ROS) to block hypoxia-induced AKI. This suggests that these particles represent a novel approach to controlling this condition.

Cancer-associated fibroblasts (CAFs) are key structural components of the tumor microenvironment and are closely associated with tumor invasion and metastasis. Lysophosphatidic acid (LPA) is a biolipid produced extracellularly and involved in tumorigenesis and metastasis. LPA has recently been implicated in the education and transdifferentiation of normal fibroblasts (NFs) into CAFs. However, little is known about the effects of LPA on CAFs and their participation in cancer cell invasion. In the present study, we identified a critical role of LPA-induced amphiregulin (AREG) secreted from CAFs in cancer invasiveness. CAFs secrete higher amounts of AREG than NFs, and LPA induces AREG expression in CAFs to augment their invasiveness. Strikingly, knocking out the AREG gene in CAFs attenuates cancer invasiveness and metastasis. Mechanistically, LPA induces Yes-associated protein (YAP) activation and Zinc finger E-box binding homeobox 1 (Zeb1) expression through the LPAR1 and LPAR3/Gi/Rho signaling axes, leading to AREG expression. Furthermore, we provide evidence that metformin, a biguanide derivative, significantly inhibits LPA-induced AREG expression in CAFs to attenuate cancer cell invasiveness. Collectively, the present data show that LPA induces AREG expression through YAP and Zeb1 in CAFs to promote cancer cell invasiveness, with the process being inhibited by metformin, providing potential biomarkers and therapeutic avenues to interdict cancer cell invasion.

BACKGROUND Hypernatremia is associated with poor outcomes in critically ill patients, and an accurate assessment of water volume is important to determine appropriate fluid hydration. Bioelectrical impedance analysis (BIA) is a new, noninvasive, and relatively easy method for measuring hydration status. This study aimed to investigate whether bioelectrical impedance measurements of body water could reduce the frequency of blood sampling for fluid replacement in patients with hypernatremia. MATERIAL AND METHODS Fifty-one hospitalized patients were studied with hypernatremia, defined as a serum sodium ≥150 mmol/L determined by laboratory testing. Laboratory and BIA measurements were compared, and water deficiency was calculated with a conventional formula (sodium-corrected Watson formula) and measured by BIA. RESULTS The value of the absolute fluid overload (AFO) equivalent to the overhydration (OH) value, determined using BIA, did not accurately represent water deficit in patients with hypernatremia (r=0.137, P=0.347). Although the total body water (TBW) measured by BIA showed a significant correlation with that determined by the conventional formula (r=0.861, P

Lysophosphatidic acid (LPA), a bioactive lipid produced extracellularly by autotaxin (ATX), has been known to induce various pathophysiological events, including cancer cell invasion and metastasis. Discoidin domain receptor 2 (DDR2) expression is upregulated in ovarian cancer tissues, and is closely associated with poor clinical outcomes in ovarian cancer patients. In the present study, we determined a critical role and signaling cascade for the expression of DDR2 in LPA-induced ovarian cancer cell invasion. We also found ectopic expression of ATX or stimulation of ovarian cancer cells with LPA-induced DDR2 expression. However, the silencing of DDR2 expression significantly inhibited ATX- and LPA-induced ovarian cancer cell invasion. In addition, treatment of the cells with pharmacological inhibitors of phosphoinositide 3-kinase (PI3K), Akt, and mTOR abrogated LPA-induced DDR2 expression. Moreover, we observed that HIF-1α, located downstream of the mTOR, is implicated in LPA-induced DDR2 expression and ovarian cancer cell invasion. Finally, we provide evidence that LPA-induced HIF-1α expression mediates Twist1 expression to upregulate DDR2 expression. Collectively, the present study demonstrates that ATX, and thereby LPA, induces DDR2 expression through the activation of the PI3K/Akt/mTOR/HIF-1α/Twist1 signaling axes, aggravating ovarian cancer cell invasion.

Background Prior studies have explored the use of regular reminders to improve adherence among kidney transplant recipients (KTRs), but none have included real-time alarms about drug dosage, frequency, and interval. In the present study, we aimed to evaluate the efficacy and stability of an information and communication technology (ICT)-based centralized monitoring system for increasing medication adherence among Korean KTRs. Methods In this prospective, multicenter, randomized controlled study, enrolled KTRs were randomized to either the ICT-based centralized monitoring group or control group. The ICT-based centralized monitoring system alerted both patients and medical staff with texts and pill box alarms if there was a missed dose or a dosage/time error. We compared the two groups in terms of medication adherence and transplant outcomes over 6 months, and evaluated patient satisfaction with the ICT-based monitoring system. Results Among 114 enrolled KTRs, 57 were assigned to the ICT-based centralized monitoring group and 57 to the control group. The two groups did not significantly differ in mean adherence at each follow-up visit. The intrapatient variability of tacrolimus and mycophenolic acid levels, renal function, and adverse transplant outcomes did not differ between the intervention and control groups, or between the intervention group with feedback generation and the intervention group without feedback generation. Patients showed high overall satisfaction with the ICT-based centralized monitoring system, which significantly improved across the study period (p = 0.012). Conclusions Due to high baseline adherence, the ICT-based centralized monitoring system did not maximize medication adherence or enhance transplant outcomes among Korean KTRs. However, patients were highly satisfied with the system. Our results suggest that the ICT-based centralized monitoring system could be successfully applied in clinical trials. Trial registration ClinicalTrials.gov, NCT03136588. Registered 20 April 2017 - Retrospectively registered.

Background and Aims Innovative strategies to promote adherence to immunosuppressants in kidney transplant recipients (KTRs) is imperative. This study aimed to evaluate the efficacy and stability of the information and communication technology (ICT)-based centralized monitoring system in increasing medication adherence in Korean KTRs. Method A prospective, multicenter, randomized controlled study was conducted (ClinicalTrials.gov Identifier: NCT03136588). All KTRs were randomized into the ICT-based centralized monitoring or the control group and had follow-up visits every 4 weeks during 6 months. The ICT-based centralized monitoring system alerted both patients and medical staff with texts and pill box alarms if there was a dosage/dosing time error or a missed dose. Medication adherence and transplant outcomes were compared between the two groups, and patient satisfaction on the ICT-based monitoring system was evaluated. Results Among enrolled 114 KTRs, 57 patients were assigned to the ICT-based centralized monitoring group and 57 patients to the control group. Mean adherence at each follow-up visit was not significantly different between groups. No differences in intrapatient variability of tacrolimus and mycophenolic acid levels, renal function, and adverse transplant outcomes were observed between the intervention and control groups, as well as between the intervention group with feedback generation and the intervention group without feedback generation. Overall patient satisfaction with the ICT-based centralized monitoring system was high and significantly improved during the study period (P = 0.012). Conclusion Although the ICT-based centralized monitoring system did not maximize mediation adherence or enhance transplant outcomes in Korean KTRs due to high baseline adherence, patient satisfaction with the system was high. We identified the future possibility that the ICT-based centralized monitoring system could be successfully applied in clinical trials targeting other disease groups with impaired adherence.

Background Colistin (polymyxin E) is an important constituent of the polymyxin class of cationic polypeptide antibiotics. Intrarenal oxidative stress can contribute to colistin-induced nephrotoxicity. Nicotinamide adenine dinucleotide 3-phosphate oxidases (Noxs) are important sources of reactive oxygen species. Among the various types of Noxs, Nox4 is predominantly expressed in the kidney. Objectives We investigated the role of Nox4 and benefit of Nox4 inhibition in colistin-induced acute kidney injury using in vivo and in vitro models. Methods Human proximal tubular epithelial (HK-2) cells were treated with colistin with or without NOX4 knockdown, or GKT137831 (most specific Nox1/4 inhibitor). Effects of Nox4 inhibition on colistin-induced acute kidney injury model in Sprague-Dawley rats were examined. Results Nox4 expression in HK-2 cells significantly increased following colistin exposure. SB4315432 (transforming growth factor-β1 receptor I inhibitor) significantly inhibited Nox4 expression in HK-2 cells. Knockdown of NOX4 transcription reduced reactive oxygen species production, lowered the levels of pro-inflammatory markers (notably mitogen-activated protein kinases) implicated in colistin-induced nephrotoxicity and attenuated apoptosis by altering Bax and caspase 3/7 activity. Pretreatment with GKT137831 replicated these effects mediated by downregulation of mitogen-activated protein kinase activities. In a rat colistin-induced acute kidney injury model, administration of GKT137831 resulted in attenuated colistin-induced acute kidney injury as indicated by attenuated impairment of glomerulus function, preserved renal structures, reduced expression of 8-hydroxyguanosine and fewer apoptotic cells. Conclusions Collectively, these findings identify Nox4 as a key source of reactive oxygen species responsible for kidney injury in colistin-induced nephrotoxicity and highlight a novel potential way to treat drug-related nephrotoxicity.

Additional file 1.

Background Amyloidosis is a very rare disease that is difficult to diagnose because of the unspecific early clinical manifestations of the disease. Accurate and early diagnosis is extremely important because the effect of treatment is dependent on the extent of disease progression. Sicca syndrome and nail dystrophy are very rare symptoms of amyloidosis. We report here a case of sicca syndrome and nail dystrophy with renal dysfunction in a 52-year-old Korean woman who was diagnosed as having systemic amyloidosis. Case presentation We present the case of a 52-year-old Korean woman complaining of dry mouth and nail dystrophy for 4 months as an initial symptom. A slit lamp examination revealed superficial keratoconjunctival erosion in both eyes. A laboratory test showed anemia, azotemia, and proteinuria. Urine protein electrophoresis showed increased gamma globulin excretion. Serum free light chain of kappa and lambda were increased. Histopathological studies of biopsy specimens of minor salivary glands and kidney revealed deposits of amyloid fibrils. A bone marrow aspiration biopsy showed hypercellular marrow with 5% plasma cells. She was diagnosed as having primary systemic amyloidosis then started on chemotherapy. Conclusion Such atypical mucocutaneous manifestations of amyloidosis can serve as important early diagnostic signs with less invasive biopsy confirmation in patients with systemic amyloidosis.

Background: The aim of this study is to evaluate the clinical outcomes between anti-thymocyte globulin (ATG) and basiliximab induction in deceased donor kidney transplantation (DDKT). Methods: Between May 2006 and February 2015, 40 patients underwent DDKT at our institution. Three cases (7.5%) of them were lost during the following-up schedule. In this study, ATG induction criteria were donor age >50 years old or donor creatinine level >1.3 mg/dL except hepatitis B virus positive and hepatitis C virus positive recipients. Recipients were divided into two groups: the ATG group (n=20) and the basiliximab group (n=17). Results: The 1-year patient survival in the ATG group was 89.4% compared to 93.8% in the basiliximab group (P=0.989). Graft survival for a 1 year in the ATG and the basiliximab group was 89.1% and 93.8%, respectively (P=0.967). Incidences of acute rejection episodes were more prevalent in the basiliximab group (15.0% vs. 29.4%, P=0.428). The glomerular filtration rate level by period of recipients was not different in both group (12th month, 64.60±16.17 mg/dL vs. 68.51±18.60 mg/dL, P=0.544). The overall complications during the follow-up were not significantly different in both groups (90.0% vs. 76.5%, P=0.383). Conclusions: The results showed that there was no difference in the patient survival and graft survival between induction of ATG and basiliximab of the DDKT were not different. Therefore, use of both induction agents led to a good patient and graft survival and ATG might be a safe and preferable agent for relatively poor renal function of donor in kidney transplantation.

Background The objective of this study was to investigate the clinical impact of BK virus surveillance on graft injury in kidney transplantation. Methods BK viremia in kidney transplant recipients was evaluated by use of plasma quantitative polymerase chain reaction. The prevalence of BK viremia and BK virus–associated nephropathy (BKVAN) and the clinical impact of BK viremia on graft outcomes were assessed. Results This study took place between January 2008 and June 2013. A total of 213 kidney transplant recipients were included. The prevalence of BK viremia and high BK viremia (≥1 × 10 4 copies/mL) was 66.7% (142/213) and 17.4% (37/213), respectively. A diagnosis of BKVAN was confirmed by means of allograft biopsy in 9 patients (4.2%). The estimated glomerular filtration rate after transplantation was similar in both the low BK viremia ( 4 copies/mL) and non–BK viremia groups but was significantly lower in the high BK viremia group after 18 months. In receiver operating characteristic curve analysis, the area under the curve value of plasma polymerase chain reaction was 0.980. We found that a viral load >92,850 copies/mL was able to predict BKVAN with 89% sensitivity and 94.6% specificity. The risk factors for viral loads ≥1 × 10 4 copies/mL were cytomegalovirus infection, steroid pulse therapy, and acute rejection. Conclusions High BK viremia was associated with poor graft function after kidney transplantation. The serial monitoring of BK viremia in kidney transplant recipients was helpful in predicting BKVAN and might prevent further progression.

Potential diseased donors manifest altered physiological changes associated with pulmonary edema, profound hemodynamic and metabolic abnormalities. These derangements may be more significant after apnea tests which result in severe hypoxemia and cardiovascular complications. Nitric oxide (NO) inhalation therapy can be applied following apnea tests in the brain-dead donor whose ventilator support has been maintained with high positive end-expiratory pressure. Inhalation of NO gas causes selective dilation of blood vessels in only those lung segments that are actively participating in gas exchange (oxygen and carbon dioxide) at the alveolar capillary level. In other words, this increases the blood flow to areas of the lung where oxygen is being provided and thus improves oxygen levels in the body. We report on the case of a 14-year-old organ donor with inhaled NO therapy after apnea testing. The duration of NO inhalation therapy was 14 hours. This deceased donor, who suffered with severe hypoxemia and hemodynamic instability after apnea tests, improved after NO gas therapy and adequate vasoactive drugs. NO gas therapy will be helpful for improving oxygen delivery to pulmonary vessels. Two kidneys and one liver were successfully retrieved from donors. These recipients had well preserved function of allografts. Therefore, NO inhalation can be help¬ful in improvement of hypoxemia and increasing organ availability in deceased organ donors.

Satisfaction Questionnaire â information and communication technology (ICT)-based centralized monitoring system. (DOCX 86Â kb)

SPIRIT 2013 Checklist: recommended items to address in a clinical trial protocol and related documents*. (DOC 123Â kb)

Background/Aims: Circulatory asymmetric dimethylarginine (ADMA) is correlated with proteinuria and endothelial dysfunction in patients with proteinuric renal diseases. However, it is not known whether proteinuria itself affects expression of dimethylarginine dimethylaminohydrolase (DDAH), a degrading enzyme of ADMA, in kidney. The aim of this study is to evaluate the direct effects of losartan and/or pentoxifylline on expression of renal DDAH-1 and its relation to oxidative stress in the setting of albuminuria. Methods: Using NRK52E cells, DDAH-1 mRNA and protein were determined after exposure to albumin with losartan and/or pentoxifylline. Reactive oxygen species (ROS), PKC activity, and NOX-4 mRNA were also measured. In addition, the effect of losartan and/or pentoxifylline on renal expression of DDAH-1 and serum ADMA were evaluated in a rat model of proteinuric nephropathy. Results: Exposure to albumin resulted in increased release of N-acetyl-β-D-glucosaminidase along with an increase of TNF-α, 8-hydroxy-2′-deoxyguanosine, and angiotensin II in NRK52E cells. Losartan and pentoxifylline reversed albumin-induced decrease of DDAH-1 mRNA and protein expression and DDAH-1 activity. The effects of losartan and pentoxifylline on DDAH-1 mRNA were associated with reduction of ROS. In addition, treatment with losartan and pentoxifylline resulted in an attenuated change of renal DDAH-1 protein expression and serum ADMA levels in vivo. Conclusion: DDAH-1 was positively regulated by losartan and pentoxifylline with its antioxidative effect in albumin-exposed renal proximal tubular cells. Combined treatment with losartan and pentoxifylline has a direct beneficial effect on expression of renal DDAH-1, and, thus, at least in part, modulates the circulatory levels of ADMA in proteinuric nephropathy.

Background We investigated the effects of gene polymorphisms on the development of IgA nephropathy and thin glomerular basement membrane (GBM) disease by analyzing polymorphisms in the interleukin (IL)-18, transforming growth factor (TGF)-β, and vascular endothelial growth factor (VEGF) genes in Korean patients. Methods This study included 146 normal individuals and 69 biopsy-proven IgA nephropathy and 44 thin GBM disease patients. The gene polymorphisms −607 A/C and −137 G/C in IL-18, −509C/T and T869C in TGF-β, and −2578C/A and 405C/G in VEGF were investigated in DNA extracted from peripheral blood. Results The frequencies of the IL-18 −607CC genotype (43.5% vs. 21.2%, P =0.002, P corrected =0.012) and the VEGF 405 GG genotype (37.7% vs. 21.2%, P =0.002, P corrected =0.012) were significantly increased in the IgA nephropathy group compared with the control group, whereas no significant differences in genotype frequency were observed between the thin GBM disease and control groups. However, there were no significant differences in genotype and allele frequencies between the IgA nephropathy and thin GBM disease groups. Conclusion This study did not show any statistically significant differences of six selected gene polymorphisms of the IL-18, TGF-β, and VEGF genes between IgA nephropathy and thin GBM disease. Additional extensive studies are required to clarify the potential role of gene polymorphism to discriminate IgA nephropathy and thin GBM disease without renal biopsy.

Background Tacrolimus is a substrate of cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp), encoded by the CYP3A and ATP-binding cassette subfamily B member 1 (ABCB1) genes, respectively. This study was aimed to investigate the impact of CYP3A and ABCB1 polymorphisms on the tacrolimus pharmacokinetics and clinical outcomes in Korean renal transplant recipients. Methods We analyzed data from a cohort of 70 renal transplant recipients receiving tacrolimus. CYP3A4*4, CYP3A4*5, CYP3A4*18, CYP3A5*3, ABCB1 C1236>T, ABCB1 G2677>T/A, and ABCB1 C3435>T polymorphisms were genotyped and correlated to dose-adjusted tacrolimus trough concentration at months 1, 3, 6, and 12 after transplantation. Results Patients with the CYP3A5*3 alleles showed higher dose-adjusted tacrolimus concentrations for 12 months and higher trough levels until 6 months after transplantation. ABCB1 polymorphisms and haplotypes were not associated with tacrolimus concentrations. In a multivariate analysis, the presence of ≥1 CYP3A5*3 allele was a significant independent variable affecting dose-adjusted tacrolimus concentrations. Glomerular filtration rate, acute rejection, opportunistic infection, and graft survival were not affected by CYP3A5 polymorphisms. Calcineurin inhibitor toxicity, which showed higher tendency in patients with CYP3A5*1 alleles, might be associated with higher tacrolimus dose per kilogram. Conclusions The CYP3A5 genotype is a major factor in determining the dose requirement of tacrolimus, and genotyping may be of value in individualization of immunosuppressive therapy of renal transplant patients.

Although erythropoietin (EPO)-related pure red-cell aplasia (PRCA) is a rare disorder, attention still needs to be paid because underline mechanism of EPO immunogenicity is various and controversial. Among several assay systems for screening of anti-EPO binding antibodies (Abs), we adopted and setup the bridging ELISA using streptavidin-coated plate. To test their neutralizing activities, cell-based neutralizing (NT) bioassay was setup. When we analyzed serum samples by using these two assays, we found two positive results in the two samples. In the sample 1, 411.9 ng/ml of anti-EPO Abs were found and neutralizing activity of 36.2% at 1:5 serum dilution was detected. In the sample 2, 40.5 ng/ml of anti-EPO Abs were found and neutralizing activity of 96.7% was detected. Our results indicate that the higher anti-EPO antibody (Ab) level in a serum does not always lead to the stronger neutralizing activity. This report gives crucial consideration to the needs of establishing clear criteria to link various assay parameters with the onset of PRCA and its progression.

Aims Ischemia/reperfusion injury, resulting from hypoxic damage within a graft, is the leading cause of cell death and graft rejection. In this study, we investigated whether Ceria-Zirconia nanoparticles (CZ NPs) as an enhanced multi-antioxidant have a great role in ischemic injury in a cellular model in which experimental hypoxia was induced using CoCl2. Main methods The ischemic injury induced in HK-2 cells by CoCl2 was validated by reduced cell viability at different times and doses. CZ NPs with size 2–3 nm were synthesized using non-hydrolytic sol-gel reaction. Results Cellular survival was reduced in a dose-dependent manner for 24 h after CoCl2 exposure. Because approximately 70% of cells survived after treatment with 300 µM of CoCl2 for 24 h, this dose was chosen for further study. CoCl2 caused a significant increase in ROS production 2 h after CoCl2. The extent of the effect of CoCl2 on ROS levels was significantly reduced by CZ NPs treatment. CZ NPs down-regulated proinflammatory markers and reduced caspase 3/7 activity in hypoxic HK-2 cells. CZ NPs also improved the survival of HK-2 cells in response to hypoxia. Conclusions CZ NPs have the potential as a therapeutic medicine for preventing ROS-related ischemia reperfusion injury after transplantation.

Background: Various studies have indicated that malnutrition and chronic inflammation are strong predictors of morbidity and mortality in patients with chronic kidney disease (CKD). The purpose of this study was to investigate the relationship between pulmonary function, malnutrition and chronic inflammation in patients with CKD. Methods: One hundred and six consenting patients with CKD were enrolled in the study between 2005 and 2007. Pulmonary function was assessed by forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and peak expiratory flow (PEF), expressed as the normal percentage of predicted values (%FEV1, %FVC and %PEF, respectively). Nutritional status was evaluated by skeletal muscle index (SMI), subjective global nutritional assessment (SGA), lean body mass, body mass index and serum albumin. Inflammation was assessed by the serum measurement of high-sensitive C reactive protein (hsCRP) levels. Results: Malnutrition (defined as SMI ≥1) and inflammation (defined as hsCRP >2 mg/l) in ESRD patients had significant negative associations with percentage predicted values for pulmonary function tests except %PEF (SMI: %FEV1, p = 0.009, %FVC, p = 0.001; hsCRP: %FEV1, p = 0.025, %FVC, p = 0.022). Multivariate Cox analysis showed that the ejection fraction in echocardiography and SGA were associated with poor survival, but there was no association for %FEV1. Conclusions: Impaired pulmonary function was associated with malnutrition and inflammation in these dialysis patients. We were not able to determine a significant relationship between pulmonary function and mortality.

Contrast-induced acute kidney injury (CIAKI) is a leading cause of acute kidney injury following radiographic procedures. Intrarenal oxidative stress plays a critical role in CIAKI. Nicotinamide adenine dinucleotide 3-phosphate (NADPH) oxidases (Noxs) are important sources of reactive oxygen species (ROS). Among the various types of Noxs, Nox4 is expressed predominantly in the kidney in rodents. Here, we evaluated the role of Nox4 and benefit of Nox4 inhibition on CIAKI using in vivo and in vitro models. HK-2 cells were treated with iohexol, with or without Nox4 knockdown, or the most specific Nox1/4 inhibitor (GKT137831). Effects of Nox4 inhibition on CIAKI mice were examined. Expression of Nox4 in HK-2 cells was significantly increased following iohexol exposure. Silencing of Nox4 rescued the production of ROS, downregulated pro-inflammatory markers (particularly phospho-p38) implicated in CIAKI, and reduced Bax and caspase 3/7 activity, which resulted in increased cellular survival in iohexol-treated HK-2 cells. Pretreatment with GKT137831 replicated these effects by decreasing levels of phospho-p38. In a CIAKI mouse model, even though the improvement of plasma blood urea nitrogen was unclear, pretreatment with GKT137831 resulted in preserved structure, reduced expression of 8-hydroxy-2’-deoxyguanosine (8OHdG) and kidney injury molecule-1 (KIM-1), and reduced number of TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling)-positive cells. These results suggest Nox4 as a key source of reactive oxygen species responsible for CIAKI and provide a novel potential option for prevention of CIAKI.

Background We prospectively studied renal transplant recipients receiving tacrolimus to determine the relationship between the CYP3A4, CYP3A5, and ABCB1 genetic polymorphisms and the pharmacokinetics (PK) and pharmacodynamics (PD) of tacrolimus and its metabolites. Methods Renal transplant recipients receiving tacrolimus were genotyped for CYP3A4*4, CYP3A4*5, CYP3A4*18, CYP3A5*3, ABCB1 c.1236C→T, ABCB1 c.2677G→A/T, and ABCB1 c.3435C→T. Dose-adjusted trough concentration (C0) of tacrolimus and its metabolites (M-I and M-III) and PK and PD (T-cell and monocyte subsets) were determined on transplantation days -2, 5, 30, and 90 and correlated with the corresponding genotypes. Results The dose-adjusted C0 of tacrolimus and its metabolites and AUC0-12 were significantly higher and the mean fluorescence intensity (MFI) of HLA/DR in monocytes was significantly lower in patients with CYP3A5*3/*3 than in patients with CYP3A5*1/*1 or CYP3A5*1/*3. However, there was no significant difference in the dose-adjusted C0 of tacrolimus and its metabolites, PK and PD among the ABCB1 genotypes. The MFI of HLA/DR in monocytes showed a significant negative correlation with dose-adjusted C0 of tacrolimus and its metabolites and AUC0-12. In a multiple regression analysis, the presence of the CYP3A5*3/*3 genotype was a significant independent variable determining the dose-adjusted C0 of tacrolimus and its metabolites, AUC0-12, and the MFI of HLA/DR in monocytes. Conclusions This study demonstrates that the CYP3A5 genetic polymorphisms are associated with the individual differences in PK and PD as well as in C0 of tacrolimus and its metabolites. The MFI of HLA/DR in monocytes might be considered to be a significant tool for monitoring tacrolimus efficacy.