Dual-responsive antibiotic and baicalein co-delivery nanoparticles with enhanced synergistic antibacterial activity.

Globally, due to the rapid development of bacterial resistance, bacterial infections lead to significant mortality and morbidity which require efficient strategies to eradicate these infections. Herein, we prepared a dual-responsive synergistic drug delivery nanoparticle carrier (NPS@Bai/Cip), which responds to sub-acid bacterial microenvironments and targets phosphatase or phospholipase at infection sites. Nanoparticles surfaces were positively (10.0 mV) charged under acidic conditions, leading to good bacterial adhesion and enhanced drug accumulation. NPS@Bai/Cip showed good antibacterial and anti-biofilm activity against drug-resistant Pseudomonas aeruginosa. NPS@Bai/Cip could inhibit the biofilm formation via affecting the swimming, swarming, and twitching motilities of P. aeruginosa. NPS@Bai/Cip was used to treat drug-resistance P. aeruginosa-induced infection in rats by improving wound healing and reducing inflammatory responses. Thus, NPS@Bai/Cip functioned as an antibacterial and antibiofilm agent with good potential for treating bacteria-induced infections.

PM2.5 and water-soluble inorganic ion concentrations decreased faster in urban than rural areas in China.

We investigated variations of PM2.5 and water-soluble inorganic ions chemical characteristics at nine urban and rural sites in China using ground-based observations. From 2015 to 2019, mean PM2.5 concentration across all sites decreased by 41.9 µg/m3 with a decline of 46% at urban sites and 28% at rural sites, where secondary inorganic aerosol (SIAs) contributed to 21% (urban sites) and 17% (rural sites) of the decreased PM2.5. SIAs concentrations underwent a decline at urban locations, while sulfate (SO42-), nitrate (NO3-), and ammonium (NH4+) decreased by 49.5%, 31.3% and 31.6%, respectively. However, only SO42- decreased at rural sites, NO3- increased by 21% and NH4+ decreased slightly. Those changes contributed to an overall SIAs increase in 2019. Higher molar ratios of NO3- to SO42- and NH4+ to SO42- were observed at urban sites than rural sites, being highest in the heavily polluted days. Mean molar ratios of NH3/NHx were higher in 2019 than 2015 at both urban and rural sites, implying increasing NHx remained as free NH3. Our observations indicated a slower transition from sulfate-driven to nitrate-driven aerosol pollution and less efficient control of NOx than SO2 related aerosol formation in rural regions than urban regions. Moreover, the common factor at urban and rural sites appears to be a combination of lower SO42- levels and an increasing fraction of NO3- to PM2.5 under NH4+-rich conditions. Our findings imply that synchronous reduction in NOx and NH3 emissions especially rural areas would be effective to mitigate NO3--driven aerosol pollution.

The role of AMP-activated protein kinase α1-mediated endoplasmic reticulum stress in alleviating the toxic effect of uremic toxin indoxyl sulfate on vascular endothelial cells by Klotho.

Recently, the Klotho protein (Klotho) has received substantial attention as protective factor against cardiovascular complications of chronic kidney disease (CKD). However, the direct effect and mechanism of Klotho on endothelial cells injury are not well-known. In this study, we incubated human vein umbilical endothelial cells (HUVECs) with uremic toxin indoxyl sulfate (IS) to mimic CKD internal environment and investigated the direct effect of Klotho on the HUVECs injury induced by IS and to explore the mechanism in this process. We found IS inhibited cell viability, increased endoplasmic reticulum stress, and mediated apoptosis of HUVECs. Treatment with Klotho significantly attenuated IS-induced above effects. Furthermore, Klotho alleviated the IS toxic effect on HUVECs via promoting AMP-activated protein kinase (AMPK) α1 phosphorylation instead of directly upregulating AMPKα1, which could be partly blocked by AMPK pathway inhibitor-Compound C. In addition, Klotho also inhibited intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression induced by IS. Altogether, these results indicated that Klotho can protect HUVECs from IS-induced injury by alleviating AMPKα1-mediated endoplasmic reticulum stress.

IgG4-related nephritis and interstitial pulmonary disease complicated by invasive pulmonary fungal infection: a case report.

BACKGROUND: IgG4-related kidney disease (IgG4-RKD) can affect multiple organs, which was first reported as a complication or extra-organ manifestation of autoimmune pancreatitis in 2004. It is characterized by abundant IgG4-positive plasma cells infiltration in tissues involved. CASE PRESENTATION: A 69-year-old man presented with cough and renal dysfunction with medical history of hypertension and diabetes. Pathological findings revealed interstitial nephritis and he was initially diagnosed with IgG4-RKD. Prednisone helped the patient to get a remission of cough and an obvious decrease of IgG4 level. However, he developed invasive pulmonary fungal infection while steroid theatment. Anti-fungal therapy was initiated after lung puncture (around cavitary lung lesion). Hemodialysis had been conducted because of renal failure and he got rid of it 2 months later. Methylprednisolone was decreased to 8 mg/day for maintenance therapy. Anti-fungal infection continued for 4 months after discharge home. On the 4th month of follow-up, Chest CT revealed no progression of lung lesions. CONCLUSIONS: The corticosteroids are the first-line therapy of IgG4-RD and a rapid response helps to confirm the diagnosis. This case should inspire clinicians to identify IgG4-related lung disease and secondary pulmonary infection, pay attention to the complications during immunosuppressive therapy for primary disease control.

Association of Glomerular Complement C4c Deposition With the Progression of Diabetic Kidney Disease in Patients With Type 2 Diabetes.

Objectives: As accumulating data supporting the potential role of the complement system in the pathogenesis of diabetic kidney disease (DKD), the present study aimed to explore the association of glomerular complement C4c deposition with the baseline clinicopathological characteristics and the prognosis of DKD in type 2 diabetes (T2DM) patients. Methods: A total of 79 T2DM patients with biopsy-proven DKD were enrolled. Clinicopathological features and renal outcomes were compared between groups divided by the glomerular C4c deposition patterns and median values of serum C4. Renal outcomes were defined by doubling of serum creatinine level or progression to end-stage renal disease (ESRD). A Cox proportional hazards model was employed to identify the risk factors associated with renal events. Results: Patients with glomerular C4c deposition had worse renal insufficiency than those without C4c deposits, along with higher 24-h urinary protein, triglyceride, but lower serum albumin and higher interstitial inflammation score. Besides, serum C4 levels positively correlated with urinary protein and serum C3 levels. During 21.85 ± 16.32 months of follow-up, Kaplan-Meier curve analysis showed significantly faster deterioration of renal function for patients with positive glomerular C4c deposition as well as higher levels of serum C4. More specifically, more than 50% of the patients with glomerular C4c had co-deposition of C3c or C1q, and patients with glomerular complement complex of C4c and one or two of C3/C1q deposition had more severe proteinuria and a higher rate of DKD progression than those with negative C4c deposits. The univariate Cox regression indicated that factors of combined serum and glomerular C4, urinary protein, serum creatinine, serum C3, combined glomerular C4c and IgM and interstitial inflammation were associated with an increased risk of DKD, but only glomerular C4c intensity (HR 1.584, 95% CI [1.001, 2.508], p = 0.0497), as well as baseline age and diabetic neuropathy, were independent risk factors for renal survival by the multivariate Cox analysis. Conclusions: Glomerular C4c deposition was associated with deteriorated renal function and outcomes in patients with T2DKD. Glomerular C4c deposition was an independent risk factor for DKD progression.

The suppressive effect of soluble Klotho on fibroblastic growth factor 23 synthesis in UMR-106 osteoblast-like cells.

Fibroblastic growth factor 23 (FGF23) is a hormone secreted primarily by bone. FGF23 is elevated in the serum of chronic kidney disease (CKD) patients, but the exact mechanism is not well known. Klotho is identified as an aging suppressor, which is mainly expressed in the kidney, and the level of soluble Klotho is negatively associated with FGF23 in CKD. The aim of this study was to investigate the effect and possible mechanism of Klotho on FGF23 synthesis in osteoblast-like UMR-106 cells. UMR-106 cells were divided into five groups: (i) control group; (ii) ß-glycerophosphate (ß-GP) group; (iii) ß-GP + Klotho group; (iv) ß-GP+ lithium chloride (LiCl, a Wnt/ß-catenin pathway agonist) group; and (v) ß-GP + Klotho + LiCl group. Subsequently, UMR-106 cells were cultured for 72 h, and the expression of FGF23, P-glycogen synthase kinase-3ß (P-GSK-3ß), and glycogen synthase kinase-3ß(GSK-3ß) were measured with Western blot analysis. The mRNA levels of FGF23 and the Wnt/ß-catenin pathway target gene c-myc were determined with RT-qPCR. The results showed that ß-GP induced increased expression of FGF23 mRNA and protein. Compared with the ß-GP group, expression of FGF23 mRNA and protein expression were downregulated in the ß-GP + Klotho group. In addition, ß-GP induced increased expression of P-GSK-3ß/GSK-3ß and c-myc, which were all downregulated in the ß-GP + Klotho group. Moreover, the expression of FGF23, P-GSK-3ß/GSK-3ß, and c-myc mRNA were upregulated when treated with LiCl. These results demonstrate that soluble Klotho suppresses FGF23 synthesis in osteoblast-like UMR-106 cells. The mechanism of this suppression may be partially through the inhibition of the Wnt/ß-catenin pathway.

Core-shell structure of Fe3O4@MTX-LDH/Au NPs for cancer therapy.

Nearly monodispersed magnetic Fe3O4@MTX-LDH/Au nanoparticles (NPs) containing the anticancer agent of methotrexate (MTX) were prepared via a coprecipitation-electrostatic interaction strategy. Firstly, layered double hydroxide (LDH) materials were deposited over the surface of Fe3O4 NPs by the coprecipitation method. Secondly, Au NPs were successfully conjugated onto the surface of LDH through electrostatic interaction. Herein, MTX was used both as the agent for surface modification and the anticancer drug for chemotherapy. These particles presented well-defined core-shell structure, strong magnetization and a high drug-loading capacity. Furthermore, the combined treatment of cancer cells by using Fe3O4@MTX-LDH/Au for synergistic hyperthermia ablation and chemotherapy was demonstrated to exhibit higher therapeutic efficacy than either single treatment alone, underscoring the great potential of the platform for cancer therapy.

Plasma microRNA signature of patients with IgA nephropathy.

We looked for differentially expressed MicroRNAs (miRNAs) in Immunoglobulin A nephropathy (IgAN). Forty-eight miRNAs were identified through the initial screening phase (2 IgAN pools vs. 1 normal control (NC) pool) using quantitative reverse transcription polymerase chain reaction (qRT-PCR) based Exiqon panel (miRCURY-Ready-to-Use-PCR-Human-panel-I + II-V1.M). By qRT-PCR, these miRNAs were further assessed in the training (32 IgAN VS. 31 NCs) and testing stages (51 IgAN VS. 51 NCs). The renal pathological lesions of patients with IgAN were evaluated according to Lee's grading system. We discovered a plasma miRNA signature including four up-regulated miRNAs (miR-148a-3p, miR-150-5p, miR-20a-5p and miR-425-3p) and the areas under the receiver operating characteristic (ROC) curve (AUC) were 0.80 and 0.76 for the training and testing stage, respectively. The expression of the four miRNAs in IgAN grade I-II subgroups (according to Lee's grading system) was obviously higher than that in IgAN grade III-V (P < .05). In summary, the plasma expression of miR-148a-3p, miR-150-5p, miR-20a-5p and miR-425-3p were up-regulated in patients with IgAN, especially the early-stage disease. Further studies are needed to explore the roles of the four miRNAs in the pathogenesis and progression of IgAN.

Induction of Au-methotrexate conjugates by sugar molecules: production, assembly mechanism, and bioassay studies.

Au-methotrexate (Au-MTX) conjugates induced by sugar molecules were produced by a simple, one-pot, hydrothermal growth method. Herein, the Au(III)-MTX complexes were used as the precursors to form Au-MTX conjugates. Addition of different types of sugar molecules with abundant hydroxyl groups resulted in the formation of Au-MTX conjugates featuring distinct characteristics that could be explained by the diverse capping mechanisms of sugar molecules. That is, the instant-capping mechanism of glucose favored the generation of peanut-like Au-MTX conjugates with high colloidal stability while the post-capping mechanism of dextran and sucrose resulted in the production of Au-MTX conjugates featuring excellent near-infrared (NIR) optical properties with a long-wavelength plasmon resonance near 630-760 nm. Moreover, in vitro bioassays showed that cancer cell viabilities upon incubation with free MTX, Au-MTX conjugates doped with glucose, dextran and sucrose for 48 h were 74.6%, 55.0%, 62.0%, and 63.1%, respectively. Glucose-doped Au-MTX conjugates exhibited a higher anticancer activity than those doped with dextran and sucrose, therefore potentially presenting a promising treatment platform for anticancer therapy. Based on the present study, this work may provide the first example of using biocompatible sugars as regulating agents to effectively guide the shape and assembly behavior of Au-MTX conjugates. Potentially, the synergistic strategy of drug molecules and sugar molecules may offer the possibility to create more gold-based nanocarriers with new shapes and beneficial features for advanced anticancer therapy.

Effects of Glycyrrhizic Acid on the Pharmacokinetics of Pristimerin in Rats and its Potential Mechanism.

BACKGROUND AND OBJECTIVES: Pristimerin has been reported to possess a wide range of pharmacological activities. This study investigates the effects of glycyrrhizic acid on the pharmacokinetics of pristimerin in rats. METHODS: The pharmacokinetics of orally administered pristimerin (2 mg/kg) with or without glycyrrhizic acid pretreatment (at a dose of 100 mg/kg/day for 7 days) were investigated. The plasma concentration of pristimerin was determined using a sensitive and reliable LC-MS/MS method, and the pharmacokinetics profiles were calculated and compared. Additionally, Caco-2 cell transwell model and rat liver microsome incubation experiments were also conducted to investigate its potential mechanism. RESULTS: The results showed that when the rats were pretreated with glycyrrhizic acid, the maximum concentration (C max) of pristimerin decreased from 186.43 ± 14.18 to 124.62 ± 18.49 ng/mL, and area under the concentration-time curve from zero to infinity (AUC0-inf) also decreased from 918.54 ± 144.72 to 504.72 ± 115.63 µg·h/L. The elimination half-life (t 1/2) value of pristimerin decreased from 3.16 ± 1.18 to 1.88 ± 0.76 h (P < 0.05). The Caco-2 cell transwell experiments indicated that glycyrrhizic acid could increase the efflux ratio of pristimerin from 2.39 to 3.64, and the rat liver microsome incubation experiments showed that glycyrrhizic acid could significantly increase its intrinsic clearance rate from 51.87 ± 5.34 to 76.79 ± 8.52 µL/min/mg protein. CONCLUSIONS: In conclusion, these results indicated that glycyrrhizic acid could affect the pharmacokinetics of pristimerin, and it might work through decreasing the absorption of pristimerin by inducing the activity of P-gp or through increasing the clearance rate in rat liver by inducing the activity of cytochrome P450 enzyme.

Novel morphologies of poly(allyamine hydrochloride)-methotrexate nanoassemblies for methotrexate delivery.

Poly(allylamine hydrochloride)-methotrexate (PAH-MTX) nanoassemblies with novel morphologies (i.e. nanostrips, nanorolls, nanosheets, and nanospheres) were achieved for the first time via supramolecular self-assembly directed by the synergistic action of various non-covalent interactions between PAH and MTX molecules in aqueous solution. Herein, MTX acted in a versatile manner as both a morphology-regulating agent and a small molecular hydrophobic anticancer drug. Moreover, different morphologies presented diverse drug release profiles, which may be caused by the distinctive interactions between PAH and MTX molecules. Synergistically non-covalent interactions, including electrostatic interactions, van der Waals forces, and hydrogen bonding, favored easier matrix corrosion and more rapid drug release of non-spherical structures (i.e. nanostrips, nanorolls, and nanosheets) through the ligand exchange process. On the other hand, the highly sealed encapsulation mode for hydrophobic MTX molecules made the nanospheres exhibit slower and better controlled release. In addition, in vitro bioassay tests showed that nanostrips displayed the most obvious suppression on the viability of cancer cells among other morphologies, especially after a longer duration. The strategy of using small molecular anticancer drugs not as passively delivered cargoes but as effective molecular building blocks, opens up a new way to develop self-delivering drugs for anticancer therapy.

Effect of pioglitazone on the calcification of rat vascular smooth muscle cells through the downregulation of the Wnt/ß­catenin signaling pathway.

The aim of the present study was to investigate the effect and possible mechanism of pioglitazone (PIO) on the calcification of rat vascular smooth muscle cells (VSMCs) in vitro. ß­glycerophosphate (ß­GP; 10 mmol/l) was used to induce calcification of VSMCs treated with a range of concentrations (5, 10, 15 and 20 µmol/l) of PIO for 12 days. Calcium deposits were revealed by Alizarin red staining. Extracellular calcium content was detected using a calcium assay kit. Western blotting was used to measure the expression of α­smooth muscle actin (α­SMA), runt­related transcription factor 2 (Runx2), bone morphogenetic protein­2 (BMP2), ß­catenin, glycogen synthase kinase­3ß (GSK­3ß), phosphorylated (p)­GSK­3ß and cyclin­D1. A total of 10 mmol/l ß­GP, 20 µmol/l PIO and 20 µmol/l peroxisome proliferator­activated receptor γ (PPAR γ) antagonist GW9662, was added to the cell culture media. The changes of the above indexes were observed. The calcium content in the calcification group, treated with high phosphorus, increased significantly compared with the controls (P<0.05) and all different concentrations of PIO reduced extracellular calcium content (P<0.05). Alizarin red staining was positive in calcified VSMCs and PIO (20 µmol/l) intervention group was almost negative. The expressions of Runx2, ß­catenin, p­GSK­3ß, BMP2 and cyclin­D1 increased significantly in the calcification group, and treatment with 20 µmol/l PIO downregulated the expression of all the above proteins, while upregulating the expression of α­SMA. The PPAR γ antagonist GW9662 could partly inhibit the effect of PIO on calcified VSMCs. The results of the present study indicated that PIO can alleviate the calcification of rat aortic VSMCs induced by ß­GP via inhibiting the activity of the Wnt/ß­catenin signaling pathway.

ß-Aminoisobutyric acid ameliorates the renal fibrosis in mouse obstructed kidneys via inhibition of renal fibroblast activation and fibrosis.

Renal fibrosis is a hallmark feature of chronic kidney disease, which is reflected by proliferation and migration of interstitial fibroblasts and extracellular matrix (ECM) accumulation. ß-Aminoisobutyric acid (BAIBA) is recently demonstrated to exert a protective role from metabolic diseases. However, whether and how BAIBA on fibroblast activation and renal fibrosis response to angiotensin II (Ang II) remains largely obscure. Herein, we showed that BAIBA significantly depressed the proliferation and migration of NRK-49F cells in vitro. Treatment with Ang II remarkably up-regulated the expressions of fibronectin (FN), collagen 1 (COL 1), α-smooth muscle actin (α-SMA), interleukin-17 (IL-17) and nicotinamide adenine dinucleotide phosphate oxidase (NOX2)-derived reactive oxygen species (ROS) production in cultured NRK-49F cells. Pretreatment with BAIBA almost blocked Ang II-induced ECM production and IL-17-mediated oxidative stress in NRK-49F cells. BAIBA treatment ameliorates fibroblasts activation and renal fibrosis in rat obstructed kidneys involving inhibition of Ang II/IL-17/ROS signaling transduction, which may be considered as a therapeutic candidate for fibrosis-related diseases.

Albumin-based nanoparticles as methylprednisolone carriers for targeted delivery towards the neonatal Fc receptor in glomerular podocytes.

Glucocorticoids (GCs) are commonly used in the treatment of nephrotic syndrome. However, high doses and long periods of GC therapy can result in severe side effects. The present study aimed to selectively deliver albumin­methylprednisolone (MP) nanoparticles towards glomerular podocytes, which highly express the specific neonatal Fc receptor (FcRn) of albumin. Bovine serum albumin (BSA) was labeled with a fluorescent dye and linked with modified MP via an amide bond. The outcome nanoparticle named BSA633­MP showed a uniform size with a diameter of approximately 10 nm and contained 12 drug molecules on average. The nanoconjugates were found to be stable at pH 7.4 and acid­sensitive at pH 4.0, with approximately 72% release of the MP drug after 48 h of incubation. The nanoparticle demonstrated a 36­fold uptake in receptor­specific cellular delivery in the FcRn­expressing human podocytes compared to the uptake in the non-FcRn-expressing control cells. Co­localization further confirmed that uptake of the nanoconjugates involved receptor­mediated endocytosis followed by lysosome associated transportation. In vitro cellular experiments indicated that the BSA633­MP ameliorated puromycin aminonucleoside­induced podocyte apoptosis. Moreover, in vivo fluorescence molecular imaging showed that BSA633-MP was mainly accumulated in the liver and kidney after intravenous dosing for 24 h. Collectively, this study may provide an approach for the effective and safe therapy of nephrotic syndrome.

Novel morphology change of Au-Methotrexate conjugates: From nanochains to discrete nanoparticles.

A novel morphology change of Au-methotrexate (Au-MTX) conjugates that could transform from nanochains to discrete nanoparticles was achieved by a simple, one-pot, and hydrothermal growth method. Herein, MTX was used efficiently as a complex-forming agent, reducing agent, capping agent, and importantly a targeting anticancer drug. The formation mechanism suggested a similarity with the molecular imprinting technology. The Au-MTX complex induced the MTX molecules to selectively adsorb on different crystal facets of gold nanoparticles (AuNPs) and then formed gold nanospheres. Moreover, the abundantly binding MTX molecules promoted directional alignment of these gold nanospheres to further form nanochains. More interestingly, the linear structures gradually changed into discrete nanoparticles by adding different amount of ethylene diamine tetra (methylene phosphonic acid) (EDTMPA) into the initial reaction solution, which likely arose from the strong electrostatic effect of the negatively charged phosphonic acid groups. Compared with the as-prepared nanochains, the resultant discrete nanoparticles showed almost equal drug loading capacity but with higher drug release control, colloidal stability, and in vitro anticancer activity.

Downregulation of paraoxonase 3 contributes to aggressive human hepatocellular carcinoma progression and associates with poor prognosis.

Paraoxonase (PON) enzymes possess antioxidant properties and protect against cardiovascular diseases. As a member of PON family, PON3 is primarily synthesized in the liver and poorly investigated. This study aimed to examine the expression of PON3 in human hepatocellular carcinoma (HCC) and investigate the clinical significance and biological function of PON3 in HCC patients. We first analyzed PON3 expression in 50 paired HCC samples (HCC tissues vs matched para-cancerous tissues) and 160 clinical HCC specimens by using immunohistochemistry (IHC). Our results showed that the expression of PON3 was downregulated in HCC and significantly associated with tumor-node-metastasis (TNM) stage, tumor size, and tumor number. Kaplan-Meier survival and Cox regression analyses showed that PON3 was an independent prognostic factor for overall survival (OS) and time to recurrence (TTR). Finally, we aimed to reveal the biological function of PON3 in HCC growth and metastasis, and our results showed that overexpression of PON3 potently inhibited growth and metastasis of HCC. Collectively, our study demonstrated that PON3 exhibited tumor-suppressive effects toward HCC and it might serve as a novel prognostic marker in HCC.

The Role and Mechanism of α-Klotho in the Calcification of Rat Aortic Vascular Smooth Muscle Cells.

OBJECTIVE: To investigate the role and possible mechanism of α-Klotho in the calcification and the osteogenic transition of cultured VSMCs. METHODS: VSMCs were cultured in vitro and divided into 5 groups, each using a different medium: (1) control; (2) ß-GP; (3) ß-GP + Klotho; (4) ß-GP + LiCl; (5) ß-GP + Klotho + LiCl. Calcium deposits were visualized using Alizarin Red S staining. The calcium concentrations were determined by the o-cresolphthalein complexone method. BMP2, Runx2 and ß-catenin levels were estimated by western blotting, and the level of α-SMA was determined by using immunofluorescence at day 12. RESULTS: ß-GP induced an increase in the expression of BMP2, Runx2, and ß-catenin. The calcium content increased, and the expression of α-SMA decreased. Alizarin Red S staining was positive under the high phosphorus conditions. BMP2, Runx2, and ß-catenin levels and the calcium content decreased when the cells were cultured with rmKlotho; however, the levels of each were upregulated after treatment with the LiCl. CONCLUSIONS: Klotho can ameliorate the calcification and osteogenic transition of VSMCs induced by ß-GP. The mechanism of Klotho in preventing calcification in VSMCs may be partially mediated by the inhibition of the Wnt/ß-catenin signaling pathway.

Mechanical and biological properties of the micro-/nano-grain functionally graded hydroxyapatite bioceramics for bone tissue engineering.

Functionally graded materials (FGM) open the promising approach for bone tissue repair. In this study, a novel functionally graded hydroxyapatite (HA) bioceramic with micrograin and nanograin structure was fabricated. Its mechanical properties were tailored by composition of micrograin and nanograin. The dynamic mechanical analysis (DMA) indicated that the graded HA ceramics had similar mechanical property compared to natural bones. Their cytocompatibility was evaluated via fluorescent microscopy and MTT colorimetric assay. The viability and proliferation of rabbit bone marrow mesenchymal stem cells (BMSCs) on ceramics indicated that this functionally graded HA ceramic had better cytocompatibility than conventional HA ceramic. This study demonstrated that functionally graded HA ceramics create suitable structures to satisfy both the mechanical and biological requirements of bone tissues.

Effect of secondary hyperparathyroidism serum on endothelial cells and intervention with Klotho.

The aim of the present study was to investigate the effect of the serum of patients with secondary hyperparathyroidism (SHPT) on endothelial cells and to examine the protective effect and the possible mechanism of Klotho. A total of three types of mixed serum from 15 patients with SHPT scheduled for parathyroidectomy, 10 chronic kidney disease (CKD) patients at stage 5 without SHPT and 15 healthy volunteers were collected. Initially, human umbilical vein endothelial cells (HUVECs) were incubated in vitro with the three types of serum and levels of proliferation were compared by assessing viable cell numbers with cell counting kit-8 (CCK-8). Subsequently, HUVECs were divided into three groups: Control group (healthy serum medium), SHPT group (SHPT serum) and Klotho treatment group (SHPT serum and Klotho). The proliferative and apoptotic levels of endothelial cells were evaluated by CCK-8 and flow cytometry, respectively. The levels of extracellular signal-regulated kinase (ERK1/2) and phosphorylated forms of ERK1/2 (p-ERK1/2) were detected using western blotting (with or without ERK1/2 inhibitor PD98059). The synthesis of nitric oxide (NO) was measured using the nitrate reduction method. The proliferation of HUVECs was inhibited by the serum from SHPT patients and CKD-5 patients without SHPT and the inhibitory effects of the SHPT serum were the most marked (P<0.05). Inhibition of HUVEC proliferation by SHPT serum occurred in a concentration-dependent manner within a specific range (5-20%; P<0.05) and also in a time-dependent manner within 6-24 h. Proliferation was partly restored and apoptosis was inhibited when 50-100 ng/ml Klotho was added into 10% SHPT serum (P<0.05). At the same time, the expression of p-ERK1/2 was upregulated, which may be inhibited by PD98059. The synthesis of NO was decreased in the SHPT group (P<0.05) and increased following treatment with Klotho (P<0.05). The results of the present study indicated that the proliferation of HUVECs was inhibited by the serum from SHPT patients. Klotho may partly antagonize this effect due to its inhibition of HUVEC apoptosis and upregulation of p-ERK1/2.

Fluvastatin inhibits the expression of fibronectin in human peritoneal mesothelial cells induced by high-glucose peritoneal dialysis solution via SGK1 pathway.

BACKGROUND: Previous studies showed that statins may have protective effects on peritoneal mesothelial cells (PMC) cultured in high glucose. However, the mechanisms are not clear yet. Several studies demonstrated that serum- and glucocorticoid-inducible kinase 1 (SGK1) is implicated in tissue fibrosis of liver, lung and kidney by regulating the expression of many profibrogenic cytokines and extracellular matrix (e.g., fibronectin). However, few available reports elucidated whether the SGK1 is involved in the pathogenesis of peritoneal fibrosis (PF) in patients with peritoneal dialysis (PD). So far, there is no study about the interaction between the statins and SGK1 in PMC. The purpose of this study was to identify whether fluvastatin may decrease the expression of fibronectin (FN) in human peritoneal mesothelial cells (HPMC) cultured with high-glucose peritoneal dialysis solution (HGPDS) by affecting SGK1 signal pathway. METHODS: Cultured HPMC were divided into groups of control, high-glucose peritoneal dialysis solution (HGPDS), HGPDS with fluvastatin (10(-8) mol/L ~ 10(-6) mol/L) or GSK650394 10(-5) mol/L (the competitive inhibitor of SGK1), fluvastatin 10(-6) mol/L or GSK650394 10(-5) mol/L alone. The expression of SGK1 and FN was detected by RT-PCR, western immunoblotting or ELISA. RESULTS: Compared with the control, the mRNA and protein expression of SGK1 and FN increased significantly in HPMC treated with HGPDS (p < 0.05). GSK650394 significantly decreased the upregulated mRNA and protein expression of SGK1 and FN induced by HGPDS (p < 0.05), and fluvastatin had the same effects as GSK650394 in a dose-dependent manner (p < 0.05). CONCLUSIONS: Expression of SGK1 and FN increased in HPMC induced by HGPDS. Treated with fluvastatin and the SGK1-inhibitor GSK650394, abnormalities of SGK1 and FN could be corrected partially, which suggested that the SGK1 pathway was implicated in the pathogenesis of PF, and that fluvastatin might decrease the expression of SGK1 so as to meliorate the progression of PF.