Luminal pressure gradient and risk of arteriovenous fistula nonmaturation.

While arteriovenous fistula (AVF) nonmaturation is a major issue of hemodialysis care, an effective treatment to improve AVF maturation remains lacking. AVF introduces pulsatile arterial blood flow into its venous limb and produces high luminal pressure gradient, which may have adverse effect on vascular remodeling. As such, the aim of the present study is to investigate effect of luminal pressure gradient on AVF nonmaturation. This single-center, prospective observational study includes patients receiving autologous AVF creation. Participants received early postoperative ultrasound 5-7 days after surgery to collect parameters including diameters, flow rates, and volume at inflow and outflow sites. Luminal pressure gradient was estimated by using modified Bernoulli equation. The outcome was spontaneous AVF maturation within 8 weeks after surgery without intervention. Thirty patients were included, of which the mean age was 66.9 years and 70% were male. At the end of study, 13 (43.3%) patients had spontaneous AVF maturation. All demographic and laboratory characteristics were similar between patients with mature and nonmature AVF. Regarding ultrasonographic parameters, nonmature AVF showed significantly higher inflow/outflow diameter ratio, inflow velocity, and luminal pressure gradient. While these 3 parameters were significantly correlated, multivariate logistic regression showed their significant association with AVF nonmaturation. Receiver operating characteristic curve exhibited their high predictive value for AVF nonmaturation. Our findings showed that higher inflow/outflow ratio, inflow velocity, and AVF luminal pressure gradient in early postoperative ultrasound predicted risk of AVF nonmaturation. Reducing inflow/outflow diameter ratio or inflow rate may be an approach to improve AVF maturation. The predictive value of this early assessment might have impact on the clinical practice of AVF care.

Oligosaccharides Ameliorate Acute Kidney Injury by Alleviating Cluster of Differentiation 44-Mediated Immune Responses in Renal Tubular Cells.

Acute kidney injury (AKI) is a sudden episode of kidney damage that commonly occurs in patients admitted to hospitals. To date, no ideal treatment has been developed to reduce AKI severity. Oligo-fucoidan (FC) interferes with renal tubular cell surface protein cluster of differentiation 44 (CD44) to prevent renal interstitial fibrosis; however, the influence of oligosaccharides on AKI remains unknown. In this study, FC, galacto-oligosaccharide (GOS), and fructo-oligosaccharide (FOS) were selected to investigate the influence of oligosaccharides on AKI. All three oligosaccharides have been proven to be partially absorbed by the intestine. We found that the oligosaccharides dose-dependently reduced CD44 antigenicity and suppressed the hypoxia-induced expression of CD44, phospho-JNK, MCP-1, IL-1ß, and TNF-α in NRK-52E renal tubular cells. Meanwhile, CD44 siRNA transfection and JNK inhibitor SP600125 reduced the hypoxia-induced expression of phospho-JNK and cytokines. The ligand of CD44, hyaluronan, counteracted the influence of oligosaccharides on CD44 and phospho-JNK. At 2 days post-surgery for ischemia-reperfusion injury, oligosaccharides reduced kidney inflammation, serum creatine, MCP-1, IL-1ß, and TNF-α in AKI mice. At 7 days post-surgery, kidney recovery was promoted. These results indicate that FC, GOS, and FOS inhibit the hypoxia-induced CD44/JNK cascade and cytokines in renal tubular cells, thereby ameliorating AKI and kidney inflammation in AKI mice. Therefore, oligosaccharide supplementation is a potential healthcare strategy for patients with AKI.

Gender and Age Differences of Genitourinary Cancers Among Chronic Dialysis Patients in Taiwan.

BACKGROUND: To investigate the age and gender differences among chronic dialysis patients who developed genitourinary cancers in Taiwan. PATIENTS AND METHODS: Incident hemodialysis patients aged 20 years or older were selected for retrospective cohort study from the National Health Insurance Research Database between 2002 and 2015, and the Taiwan Cancer Registry Database between 2007 and 2015. A two-step approach was employed to find the respective matched controls of non-dialysis patients. Finally, 65,450 dialysis patients and 261,800 non-dialysis patients were matched for further analysis. New diagnosis of genitourinary cancers during follow-up was the primary outcome of interest. RESULTS: Dialysis was significantly associated with increased risk of all types of genitourinary cancers (P < .001), substantially within the first two years after dialysis initiation. Cox proportional hazard analysis showed a significantly increased hazard ratio (HR 6.58, 95% CI 6.05-7.16) among dialysis patients after multivariate adjustment, and the highest risk was bladder cancer (HR 7.85, 95% CI 6.97-8.84). Subgroup analysis showed younger dialysis patients (20-49 years old) had the highest risk of genitourinary cancer, especially females, in this subgroup with the highest risk of bladder cancer (HR 58.08, 95% CI 13.88-243.06). CONCLUSION: The risks of all site-specific genitourinary cancers were increased in chronic dialysis patients, especially in younger females. Developing different screening strategies for these high-risk patients is necessary. MICRO ABSTRACT: This study compared the effect of sex, age and dialysis duration on the susceptibility to develop genitourinary cancers in dialysis patients through the national health database linkage in Taiwan. We matched 65,450 dialysis patients and 261,800 non-dialysis patients for further analysis. Younger and female dialysis patients were at higher risk of kidney and bladder cancers.

Renal protective effect of sacubitril/valsartan in patients with heart failure.

Sacubitril/valsartan is a combined neprilysin inhibitor/angiotensin II receptor blocker designed for treatment of heart failure (HF). Nonetheless, its renal protective effect remained an issue of debate. This retrospective cohort study investigated the renal protective effect of sacubitril/valsartan in HF patients. HF patients on sacubitril/valsartan or valsartan for > 30 days were matched for gender, age, estimated glomerular filtration rate (eGFR), and left ventricular ejection fraction (LVEF) to be enrolled into analysis. The follow-up period was 18 months. The outcomes included end eGFR, renal function decline defined as 20% reduction of eGFR, mortality, and HF-related hospitalization. Each group had 137 patients after matching. The mean age was 72.7 years and 65.7% were male. Mean eGFR was 70.9 mL/min/1.73 m2 and LVEF was 54.0% at baseline. Overall, the eGFR of sacubitril/valsartan groups was significantly higher than valsartan group at the end (P < 0.01). Subgroup analysis showed that the difference in eGFR was significant in subgroups with LVEF ≥ 40% or eGFR ≥ 60 mL/min/1.73 m2. Multivariate Cox regression model showed that sacubitril/valsartan group had significantly reduced risk for renal function decline (hazard ratio: 0.5, 95% confidence interval: 0.3-0.9). Kaplan-Meier curve showed no difference in the risk for cardiovascular mortality, all-cause mortality or HF-related hospitalization. We showed renal protective effect of neprilysin inhibition in HF patients and specified that subgroups with LVEF ≥ 40% or eGFR ≥ 60 mL/min/1.73 m2 were sensitive to this effect, suggesting an optimal subgroup of this treatment.

Parathyroid Hormone Induces Transition of Myofibroblasts in Arteriovenous Fistula and Increases Maturation Failure.

CONTEXT: Arteriovenous fistula (AVF) maturation failure remains a clinical dilemma, and its pathobiology is largely unclear. Secondary hyperparathyroidism is a complication of chronic renal failure that is associated with cardiovascular disease. While parathyroid hormone (PTH) has a prosclerotic effect on vascular smooth muscle cells (VSMCs), its role in AVF maturation failure remained unknown. OBJECTIVE: This work aimed to investigate the association between plasma PTH and AVF maturation. METHODS: Patients receiving AVF creation were enrolled retrospectively. A mouse model of secondary hyperparathyroidism and aortocaval AVF was used to investigate the effect of PTH on an AVF lesion. A cell model of VSMCs treated with PTH in a pressurized culture system was used to disclose the signaling pathway underlying the effect of PTH on an AVF lesion. RESULTS: In patients receiving AVF creation, higher PTH was associated with an increased risk for maturation failure. In a mouse model, vascular wall thickness and myofibroblasts of AVF significantly increased with higher PTH. When the same mice were treated with cinacalcet, AVF lesions were attenuated by suppression of PTH. A cell model showed that PTH increased the marker of myofibroblasts, integrin ß6 subunit (ITGB6), via the phosphorylated protein kinase B pathway. Finally, in the same model of mice AVF, higher PTH also increased the expression of ITGB6 in the smooth muscle layer of AVF, suggesting the transition to myofibroblast. CONCLUSION: Overall, our results suggest that higher PTH increased the risk of AVF maturation failure through increasing the transition of VSMCs to myofibroblasts. Lowering PTH may be a strategy to enhance AVF maturation.

Combined protective effects of oligo-fucoidan, fucoxanthin, and L-carnitine on the kidneys of chronic kidney disease mice.

Chronic kidney disease (CKD) is a common global progressive disease, but there are no ideal drugs for the treatment. Fucoidan and fucoxanthin, and L-carnitine are one of the very few natural products that have a therapeutic effect on CKD in animal experiments. However, the combined effects of these compounds on CKD are unknown. We established a mouse CKD model by right nephrectomy with transient ischemic injury to the left kidney. Oligo-fucoidan and fucoidan were extracted from Laminaria japonica. We fed CKD mice with the two compounds and L-carnitine to evaluate the combined effects on CKD. Oligo-fucoidan and fucoidan inhibited renal fibrosis and reduced serum creatine in CKD mice to a greater extent than any single compound. L-carnitine had no measurable effect on renal fibrosis but promoted the protective effect of the mixture of oligo-fucoidan and fucoidan on renal function in CKD mice. In the two-month safety test, the combined mixture further improved renal function and did not elevate serum aspartate aminotransferase and alanine aminotransferase levels in CKD mice. Furthermore, the weights of CKD mice treated with the combination increased to the normal level. We also found that all oligo-fucoidan, fucoxanthin, and L-carnitine inhibit H2O2-induced apoptosis and activated Akt in rat renal tubular cells. Our results confirm that oligo-fucoidan, fucoxanthin, and L-carnitine have a combined protective effect on the kidneys. The combined mixture may be beneficial for CKD patients.

Author Correction: Simvastatin reduces the carcinogenic effect of 3-methylcholanthrene in renal epithelial cells through histone deacetylase 1 inhibition and RhoA reactivation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Increased Risk of Cutaneous Squamous Cell Carcinoma in Organ Transplant Recipients and Patients on Chronic Dialysis: A Cancer Registry-based Study in Taiwan.

This study investigated the predominant skin cancer subtype among organ transplant recipients, patients on chronic dialysis, and patients with chronic kidney disease in Asian subjects. Among 23,644 patients with skin cancer, identified from Taiwan Cancer Registry Database, 53 were organ transplant recipients, 255 were on chronic dialysis, 1,792 had chronic kidney disease, and 21,544 were in the control group. The proportions of squamous cell carcinoma were 52.8%, 47.8%, 40.1%, and 33.5%, respectively. Compared with the control group, organ transplant recipients (1.99-fold) and patients on chronic dialysis (1.25-fold) were at higher risk of developing squamous cell carcinoma than other skin cancers after adjustment for potential confounders. Subgroups or covariates associated with increased squamous cell carcinoma compared with other skin cancer risk included patients with chronic kidney disease aged < 70 years (vs. control group; 1.3-fold), old age (vs. young age; 2.8-fold), male sex (vs. female sex; 1.1-fold), and south Taiwan residency (vs. north Taiwan residency; 1.1-fold). Organ transplant recipients and patients on chronic dialysis had immune dysregulation, resulting in a higher risk of squamous cell carcinomas.

Study protocol for a prospective observational study to investigate the role of luminal pressure on arteriovenous fistula maturation.

INTRODUCTION: Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis due to its higher patency and lower infection rate. However, its suboptimal maturation rate is a major weakness. Although substantial risk factors for AVF maturation failure have been disclosed, modifiable risk factors remain unknown. During the AVF maturation process, an elevated luminal pressure is required for outward remodeling; however, excessively high luminal pressure may also be detrimental to AVF maturation, which remains to be defined. We hypothesized that higher AVF luminal pressure is harmful to its maturation, and investigate its potential as a modifiable factor to improve AVF maturation. METHODS AND ANALYSIS: This prospective study includes patients undergoing surgical creation for a native AVF. The exclusion criteria were as follows: age <20 years, inability to sign an informed consent, and failure to create a native AVF due to technical difficulties. Demographic and laboratory profiles will be collected before AVF surgery. Vascular sonography will be performed within 1 week of AVF creation to measure the diameters, flow rates, and flow volumes of AVF and its branched veins. The pressure gradient within AVF will be estimated from the blood flow rates using the modified Bernoulli equation. The primary outcome is spontaneous AVF maturation defined as provision of sufficient blood flow for hemodialysis within 2 months of its creation without any interventional procedures. The secondary outcome is assisted AVF maturation, which is defined as AVF maturation within 2 months from its creation aided by any interventional procedure before the successful use of AVF. DISCUSSION: While contemporary theory for AVF maturation failure focuses on disturbed wall shear stress, complicate assumptions and measurement preclude its clinical applicability. AVF luminal pressure, which may be manipulated pharmaceutically and surgically, may be a target to improve the outcome of AVF maturation. TRIAL REGISTRATION: This study has been registered at the protocol registration and results system. The Protocol ID: NCT04017806.

Simvastatin reduces the carcinogenic effect of 3-methylcholanthrene in renal epithelial cells through histone deacetylase 1 inhibition and RhoA reactivation.

The therapeutic effects of simvastatin for renal cell carcinoma (RCC) are controversial. In this study, the effects of simvastatin on the carcinogenic properties of 3-methylcholanthrene (3MC; an aryl-hydrocarbon receptor [AhR] agonist) in human renal epithelial cells (hRECs) were investigated. We exposed in vitro and in vivo models to 3MC to induce RCC onset. 3MC upregulated the epithelial-mesenchymal transition (EMT) and tumor biomarkers; the models exhibited the reciprocal expression of histone deacetylase 1 (HDAC1) and RhoA, namely increased HDAC1 and decreased RhoA expression, through hypoxia-inducible-factor (HIF)- and AhR-dependent mechanisms. In addition to inducing EMT biomarkers, 3MC decreased von Hippel-Lindau protein levels (a risk factor for RCC) and increased CD44 expression in hRECs, which were reversed by digoxin (a HIF inhibitor) and HDAC inhibitors (suberoylanilide hydroxamic acid and trichostatin A [TSA]). Simvastatin abolished the detrimental effects of 3MC by reducing HDAC1 expression, with resulting RhoA upregulation, and reactivating RhoA in vitro and in vivo. Notably, the protective effects of simvastatin were negated by an HDAC activator (ITSA) through TSA suppression. The crucial role of RhoA in RCC carcinogenesis was verified by the overexpression of constitutively active RhoA. Collectively, these results demonstrate that simvastatin restores RhoA function through HDAC1 inhibition; therefore, simvastatin might serve as adjunct therapy for RCC induced by 3MC.

Synergistic effects of cAMP-dependent protein kinase A and AMP-activated protein kinase on lipolysis in kinsenoside-treated C3H10T1/2 adipocytes.

BACKGROUND: We previously showed that 3-O-ß-D-glucopyranosyl-(3R)-hydroxybutanolide (kinsenoside), a major compound of Anoectochilus formosanus, increased lipolysis through an AMP-activated protein kinase (AMPK)-dependent pathway. PURPOSE: To extend our previous finding, we investigated the in vivo and in vitro effects of kinsenoside on lipolysis and the involvement of cyclic AMP (cAMP)-dependent protein kinase A (PKA) and AMPK in kinsenoside-mediated lipolysis. STUDY DESIGN/METHODS: Mice were fed a high-fat diet for six weeks to induce lipid deposition and then treated with 50 and 100  mg/kg kinsenoside for two weeks. The coordination of PKA and AMPK activation in lipolysis in C3H10T1/2 adipocytes was evaluated in vitro by using PKA and AMPK's corresponding inhibitors, oil-red O staining, a glycerol production assay, and Western blot analysis. RESULTS: Kinsenoside reduced body weight, fat pad mass, and hepatic lipid accumulation in obese mice, and concurrently increased the induction and activation of hormone-sensitive lipase (HSL), perilipin, adipose triglyceride lipase (ATGL), and carnitine palmitoyltransferase I (CPT1). Kinsenoside concentration-dependently increased PKA activation by increasing the phosphorylation of Ser/Thr-PKA substrates in vitro. These increases were accompanied by a reduction in fat accumulation. Using H89 and Rp-8-Br-cAMPs to inhibit PKA reduced the release of glycerol but did not alter the activation of peroxisome proliferator-activated receptor alpha or the expression of CPT1 or ATGL. By contrast, compound C, an AMPK inhibitor, inhibited CPT1 and ATGL expression in kinsenoside-treated C3H10T1/2 adipocytes. In addition, H89 caused the reactivation of AMPK downstream targets by increasing the levels of the active form of pAMPK-Thr172, suggesting that PKA negatively modulates AMPK activity. CONCLUSION: Kinsenoside increased HSL activation through PKA-mediated phosphorylation at Ser660/563 and concomitantly increased perilipin activation in lipolysis. These lipolytic effects of kinsenoside were validated using 6-Bnz-cAMPs, a PKA agonist. In this study, we demonstrated that in addition to AMPK, PKA also plays a crucial role in kinsenoside-mediated lipolysis.

Alleviative effect of fucoxanthin-containing extract from brown seaweed Laminaria japonica on renal tubular cell apoptosis through upregulating Na+/H+ exchanger NHE1 in chronic kidney disease mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Brown seaweed is a common food for Asians, and the bioactive ingredient fucoxanthin exerts anti-apoptotic activities in several cell types. Renal tubular cell apoptosis is one of the common cellular events leading to renal fibrosis and chronic kidney disease (CKD). However, the influence of fucoxanthin-containing brown seaweed extract on CKD is still unknown. We intended to evaluate the inhibitory effect of fucoxanthin-containing extract from brown seaweed on renal apoptosis under CKD condition and its molecular mechanism. MATERIALS AND METHODS: The fucoxanthin-containing brown seaweed extract (LJE) was prepared from Laminaria japonica. We investigated how LJE influences on both doxorubicin-treated rat renal tubular cells (NRK-52E) and the renal symptoms of nephrectomy-induced CKD mice. RESULTS: LJE inhibited doxorubicin-induced apoptosis and upregulated Na+/H+ exchanger isoform 1 (NHE1) expression in NRK-52E cells, which were blocked by the NHE1 inhibitor cariporide. LJE also upregulated peroxisome proliferator-activated receptor alpha (PPARα). PPARα siRNA transfection inhibited LJE-induced NHE1 expression and anti-apoptotic effect. In CKD mice, LJE increased NHE1 expression in renal tubules and reduced apoptotic renal tubular cells, but not in PPARα knockout mice. The inhibitory effect of LJE on apoptosis also reduced renal tubulointerstitial fibrosis and improved renal function in CKD mice. CONCLUSION: We demonstrated that LJE inhibits renal apoptosis via NHE1 upregulation. The anti-apoptotic effect of LJE also improves renal function in CKD mice. Therefore, fucoxanthin-containing brown seaweed may have a therapeutic potential for CKD patients.

Role of activating transcription factor 3 in fructose-induced metabolic syndrome in mice.

Activating transcription factor 3 (ATF3) has been implicated in cardiovascular disease and inflammation. This study examined the effects of ATF3 knockout (KO) on blood pressure, glucose intolerance, dyslipidemia, inflammation, and visceral adiposity in mice fed who did and did not consume a high-fructose diet. Male mice were divided into four groups (N = 15 for each group): the Con (control) group (wild-type mice fed a standard chow diet), Fru group (wild-type mice fed a high-fructose [60% fructose] diet), ATF3KO-Con group (ATF3 KO mice fed a standard chow diet), and ATF3KO-Fru group (ATF3 KO mice fed a high-fructose [60% fructose] diet). Experiments were conducted for 8 weeks. Our data demonstrated that ATF3 KO mice have lower systolic blood pressure (SBP) levels than do wild-type mice, and that high-fructose diets increase SBP levels in both wild-type and ATF3 KO mice. ATF3 KO in mice increased the serum levels of glucose, insulin, triglycerides, tumor necrosis factor-alpha, and intercellular adhesion molecule-1, impaired endothelium-dependent aortic relaxation, increased aorta wall thickness and lipid peroxide, and expanded visceral adiposity. These symptoms resembled those exhibited by the wild-type mice fed a high-fructose diet, which caused hyperglycemia, insulin resistance, dyslipidemia, endothelium-dependent aortic dysfunction, inflammation, aorta remodeling, and visceral adiposity. A high-fructose diet among ATF3 KO mice deteriorated metabolic parameters and inflammatory cytokines. The present results therefore suggest that ATF3 deficiency is involved in the pathogenesis of metabolic syndrome and ATF3 might have a therapeutic role in fructose-induced impairment of endothelium-dependent aortic relaxation, a rising of inflammatory cytokines, and metabolic syndrome.

Risk of Non-melanoma Skin Cancer in Patients with Chronic Kidney Disease and its Relationship to Uraemic Pruritus.

This study investigated the risk of non-melanoma skin cancer (NMSC) in pre-dialysis patients with chronic kidney disease (CKD) and explored associated risk factors. A population-based cohort of 1,515,858 Taiwanese CKD patients was included. The standardized incidence ratio (SIR) for incident NMSC was determined. Compared with the general population, a 1.14-fold risk of NMSC was found in the CKD cohort. NMSC risk was significant in patients with pre-dialysis stage 5 CKD and anaemia (1.48-fold), and in those with uraemic pruritus after long-term antihistamine treatment (1.38-fold). A higher SIR for NMSC was found in younger patients with CKD (age < 70 years, 1.34-fold; age 20-39 years, 1.63-fold), stage 5 CKD with anaemia (age < 70 years, 2.09-fold), and uraemic pruritus (age <70 years, 2.22-fold). Pre-dialysis patients with CKD are at higher risk of NMSC, especially those with advanced-stage CKD, and those with uraemic pruritus.

Oligo-fucoidan prevents renal tubulointerstitial fibrosis by inhibiting the CD44 signal pathway.

Tubulointerstitial fibrosis is recognized as a key determinant of progressive chronic kidney disease (CKD). Fucoidan, a sulphated polysaccharide extracted from brown seaweed, exerts beneficial effects in some nephropathy models. The present study evaluated the inhibitory effect of oligo-fucoidan (800 Da) on renal tubulointerstitial fibrosis. We established a mouse CKD model by right nephrectomy with transient ischemic injury to the left kidney. Six weeks after the surgery, we fed the CKD mice oligo-fucoidan at 10, 20, and 100 mg/kg/d for 6 weeks and found that the oligo-fucoidan doses less than 100 mg/kg/d improved renal function and reduced renal tubulointerstitial fibrosis in CKD mice. Oligo-fucoidan also inhibited pressure-induced fibrotic responses and the expression of CD44, ß-catenin, and TGF-ß in rat renal tubular cells (NRK-52E). CD44 knockdown downregulated the expression of ß-catenin and TGF-ß in pressure-treated cells. Additional ligands for CD44 reduced the anti-fibrotic effect of oligo-fucoidan in NRK-52E cells. These data suggest that oligo-fucoidan at the particular dose prevents renal tubulointerstitial fibrosis in a CKD model. The anti-fibrotic effect of oligo-fucoidan may result from interfering with the interaction between CD44 and its extracellular ligands.

L-carnitine protects against carboplatin-mediated renal injury: AMPK- and PPARα-dependent inactivation of NFAT3.

We have previously shown that carboplatin induces inflammation and apoptosis in renal tubular cells (RTCs) through the activation of the nuclear factor of activated T cells-3 (NFAT3) protein by reactive oxygen species (ROS), and that the ROS-mediated activation of NFAT3 is prevented by N-acetyl cysteine and heme oxygenase-1 treatment. In the current study, we investigated the underlying molecular mechanisms of the protective effect of L-carnitine on carboplatin-mediated renal injury. Balb/c mice and RTCs were used as model systems. Carboplatin-induced apoptosis in RTCs was examined using terminal-deoxynucleotidyl-transferase-mediated dUTP nick end labeling. We evaluated the effects of the overexpression of the peroxisome-proliferator-activated receptor alpha (PPARα) protein, the knockdown of PPARα gene, and the blockade of AMPK activation and PPARα to investigate the underlying mechanisms of the protective effect of L-carnitine on carboplatin-mediated renal injury. Carboplatin reduced the nuclear translocation, phosphorylation, and peroxisome proliferator responsive element transactivational activity of PPARα. These carboplatin-mediated effects were prevented by L-carnitine through a mechanism dependent on AMPK phosphorylation and subsequent PPARα activation. The activation of PPARα induced cyclooxygenase 2 (COX-2) and prostacyclin (PGI2) synthase expression that formed a positive feedback loop to further activate PPARα. The coimmunoprecipitation of the nuclear factor (NF) κB proteins increased following the induction of PPARα by L-carnitine, which reduced NFκB transactivational activity and cytokine expression. The in vivo study showed that the inactivation of AMPK suppressed the protective effect of L-carnitine in carboplatin-treated mice, indicating that AMPK phosphorylation is required for PPARα activation in the L-carnitine-mediated protection of RTC apoptosis caused by carboplatin. The results of our study provide molecular evidence that L-carnitine prevents carboplatin-mediated apoptosis through AMPK-mediated PPARα activation.

MicroRNA-328 inhibits renal tubular cell epithelial-to-mesenchymal transition by targeting the CD44 in pressure-induced renal fibrosis.

Epithelial-mesenchymal transition (EMT) occurs in stressed tubular epithelial cells, contributing to renal fibrosis. Initial mechanisms promoting EMT are unknown. Pressure force is an important mechanism contributing to the induction and progression of renal fibrogenesis in ureteric obstruction. In our study of cultured rat renal tubular cells (NRK-52E) under 60 mmHg of pressure, we found that the epithelial marker E-cadherin decreased and mesenchymal markers, e.g., α-smooth muscle actin, fibronectin and Snail, increased. Pressure also induced the expression of connective tissue growth factor and transforming growth factor-ß. MicroRNA array assays showed that pressure reduced miR-328 at the initial stage of pressurization. We identified a potential target sequence of miR-328 in rat CD44 3'-untranslated regions. In contrast with the miR-328 expression, CD44 expression was up-regulated at the initial pressurization stage. We also found that miR-328 expression decreased and CD44 increased in ureteric obstruction kidneys in the animal study. CD44 siRNA transfection significantly increased E-cadherin expression and inhibited pressure-induced EMT. Both hyaluronan binding peptide pep-1 and osteopontin neutralizing antibody inhibited pressure-induced EMT. Our results suggest that miR-328-mediated CD44 transient upregulation is an important trigger of the pressure-induced EMT in renal fibrosis.

3-Methylcholanthrene, an AhR agonist, caused cell-cycle arrest by histone deacetylation through a RhoA-dependent recruitment of HDAC1 and pRb2 to E2F1 complex.

We previously showed that treating vascular endothelial cells with 3-methylcholanthrene (3MC) caused cell-cycle arrest in the Go/G1 phase; this resulted from the induction of p21 and p27 and a decreased level and activity of the cyclin-dependent kinase, Cdk2. We further investigated the molecular mechanisms that modulate cell-cycle regulatory proteins through the aryl-hydrocarbon receptor (AhR)/Ras homolog gene family, member A (RhoA) dependent epigenetic modification of histone. AhR/RhoA activation mediated by 3MC was essential for the upregulation of retinoblastoma 2 (pRb2) and histone deacetylase 1 (HDAC1), whereas their nuclear translocation was primarily modulated by RhoA activation. The combination of increased phosphatase and tensin homolog (PTEN) activity and decreased phosphatidylinositide 3-kinase (PI3K) activation by 3MC led to the inactivation of the Ras-cRaf pathway, which contributed to pRb2 hypophosphorylation. Increased HDAC1/pRb2 recruitment to the E2F1 complex decreased E2F1-transactivational activity and H3/H4 deacetylation, resulting in the downregulation of cell-cycle regulatory proteins (Cdk2/4 and Cyclin D3/E). Co-immunoprecipitation and electrophoretic mobility shift assay (EMSA) results showed that simvastatin prevented the 3MC-increased binding activities of E2F1 proteins in their promoter regions. Additionally, RhoA inhibitors (statins) reversed the effect of 3MC in inhibiting DNA synthesis by decreasing the nuclear translocation of pRb2/HDAC1, leading to a recovery of the levels of cell-cycle regulatory proteins. In summary, 3MC decreased cell proliferation by the epigenetic modification of histone through an AhR/RhoA-dependent mechanism that can be rescued by statins.

Urotensin II exerts antiapoptotic effect on NRK-52E cells through prostacyclin-mediated peroxisome proliferator-activated receptor alpha and Akt activation.

Urotensin II (UII) is a cyclic vasoactive peptide which is mainly expressed in kidneys. Although elevated plasma UII levels are associated with renal impairment, the influence of UII on renal injury is unclear. In this study, we monitored the influence of UII on gentamicin-induced apoptosis in rat tubular cells (NRK-52E). We found that UII significantly reduced gentamicin-induced apoptosis and apoptotic signals. Blocking endogenous UII secretion caused cells to be more susceptible to gentamicin. In gentamicin-treated mice, UII also expressed protective effect on renal tubular cells. UII was also found to induce prostacyclin (PGI2) production, which caused peroxisomal proliferator-activated receptor α (PPARα) activation as revealed by both PGI2 synthase siRNA transfection and piroxicam treatment. Blockage of PPARα by siRNA transfection inhibited UII-induced Akt phosphorylation and the antiapoptotic effect of UII. Our results suggest that UII can protect renal tubular cells from gentamicin-induced apoptosis through PGI2-mediated PPARα and Akt activation.

Treatment of cosmetic tattoos with nonablative fractional laser in an animal model: a novel method with histopathologic evidence.

BACKGROUND AND OBJECTIVE: Cosmetic tattoos are difficult to treat using Q-switched lasers. We introduce a novel method for the treatment of cosmetic tattoos using a nonablative fractional laser and investigate the underlying pathophysiological mechanisms in an animal model. STUDY DESIGN/MATERIALS AND METHODS: Ten rats were tattooed on their backs with white and flesh-colored pigments. One-half of each tattoo was treated with a 1,550-nm, erbium:glass fractional laser system with energy settings of 17 mJ and 169 MTZ/cm(2) × 2 passes for five sessions at 1-month intervals. The untreated half of each tattoo served as the control. An independent physician reviewed the photographs and scored the clinical response. Serial skin samples were obtained at baseline and at various times after laser treatment. These tissue sections were stained with hematoxylin and eosin, and immunostained for types I, III, and IV collagen; laminin; fibronectin; and α-smooth muscle actin. RESULTS: White tattoos showed excellent responses in two rats and good responses in eight rats, whereas flesh-colored tattoos showed excellent responses in four rats and good responses in six rats (P = 0.001 in both cases compared with baseline). Both tattoos exhibited a similar clearance rate (P > 0.05) and histological reactions. Microscopic epidermal necrotic debris (MEND) containing tattoo pigments and collagen fibrils appeared on day 1, increased on day 2, and was exfoliated after 5 days. The dermal-epidermal junction lost integrity 30 minutes after treatment, but recovered completely on day 3. The expression of fibronectin and collagen-III, which play key roles in wound healing, increased around the microscopic treatment zone on days 1-5 and 4-7, respectively. A few myofibroblasts appeared on days 4-7. CONCLUSION: Nonablative fractional lasers (NAFLs) successfully remove cosmetic tattoos by transepidermal elimination of tattoo pigments through the disrupted dermal-epidermal junction. This action is facilitated by the wound healing process.