Normal Physiological Concentrations Research Articles

Electrochemical biosensor with ceria–polyaniline core shell nano-interface for the detection of carbonic acid in blood

The normal physiological concentration of carbonic acid in human blood is in the range of 1.08–1.32mM. However, if the concentration of carbonic acid rises above 3.45mM, it may lead to respiratory acidosis. In this context, an electrochemical biosensor with CeO2–PANI (polyaniline) core–shell nano-interface was developed for sensing carbonic acid using carbonic anhydrase (CA). CA was immobilized on CeO2–PANI via chitosan on a glassy carbon electrode (GCE/CeO2–PANI/CA/chitosan). The X-ray diffraction (XRD) patterns confirmed the polycrystalline nature of CeO2 and CeO2–PANI nanoparticles. Field emission scanning electron microscopy (FE-SEM) studies showed the aggregation of spherical nanoparticles with size ranging from 37.6 to 47.8nm and Field emission transmission electron microscopy (FE-TEM) study confirmed the presence of core–shell structure of CeO2–PANI. Immobilization of CA on CeO2–PANI was confirmed by Fourier transform infrared (FT-IR) spectra. Electrochemical studies were carried out with the help of GCE/CeO2–PANI/CA as a working electrode, Ag/AgCl saturated with 0.1M KCl as a reference electrode and Pt wire as a counter electrode. This biosensor exhibited sensitivity of 696.49μAcm−2mM−1 with a linear range of 1.32–2.32mM. It also showed a fast response time of less than 1s, lowest detection limit of 19.4μM, Michaelis–Menten constant (KM) of 1.8191mM and dry stability of 96% up to 18days. The observed results revealed the potential of the modified working electrode with CeO2–PANI core–shell nano-interface for carbonic acid sensing. The developed biosensor can be applied for the real time clinical diagnosis of diseases such as obstructive pulmonary diseases (COPD).

Testosterone Rapidly Increases Neural Reactivity to Threat in Healthy Men: A Novel Two-Step Pharmacological Challenge Paradigm

Previous research suggests that testosterone (T) plays a key role in shaping competitive and aggressive behavior in humans, possibly by modulating threat-related neural circuitry. However, this research has been limited by the use of T augmentation that fails to account for baseline differences and has been conducted exclusively in women. Thus, the extent to which normal physiologic concentrations of T affect threat-related brain function in men remains unknown. In the current study, we use a novel two-step pharmacologic challenge protocol to overcome these limitations and to evaluate causal modulation of threat- and aggression-related neural circuits by T in healthy young men (n = 16). First, we controlled for baseline differences in T through administration of a gonadotropin releasing hormone antagonist. Once a common baseline was established across participants, we then administered T to within the normal physiologic range. During this second step of the protocol we acquired functional neuroimaging data to examine the impact of T augmentation on neural circuitry supporting threat and aggression. Gonadotropin releasing hormone antagonism successfully reduced circulating concentrations of T and brought subjects to a common baseline. Administration of T rapidly increased circulating T concentrations and was associated with heightened reactivity of the amygdala, hypothalamus, and periaqueductal grey to angry facial expressions. These findings provide novel causal evidence that T rapidly potentiates the response of neural circuits mediating threat processing and aggressive behavior in men.

Microneedle‐Based Transdermal Sensor for On‐Chip Potentiometric Determination of K+

The determination of electrolytes is invaluable for point of care diagnostic applications. An ion selective transdermal microneedle sensor is demonstrated for potassium by integrating a hollow microneedle with a microfluidic chip to extract fluid through a channel towards a downstream solid-state ion-selective-electrode (ISE). 3D porous carbon and 3D porous graphene electrodes, made via interference lithography, are compared as solid-state transducers for ISE's and evaluated for electrochemical performance, stability, and selectivity. The porous carbon K(+) ISE's show better performance than the porous graphene K(+) ISE's, capable of measuring potassium across normal physiological concentrations in the presence of interfering ions with greater stability. This new microfluidic/microneedle platform shows promise for medical applications.

Extracellular Allosteric Na+ Binding to the Na+,K+-ATPase in Cardiac Myocytes

Whole-cell patch-clamp measurements of the current, Ip, produced by the Na+,K+-ATPase across the plasma membrane of rabbit cardiac myocytes show an increase in Ip over the extracellular Na+ concentration range 0–50 mM. This is not predicted by the classical Albers-Post scheme of the Na+,K+-ATPase mechanism, where extracellular Na+ should act as a competitive inhibitor of extracellular K+ binding, which is necessary for the stimulation of enzyme dephosphorylation and the pumping of K+ ions into the cytoplasm. The increase in Ip is consistent with Na+ binding to an extracellular allosteric site, independent of the ion transport sites, and an increase in turnover via an acceleration of the rate-determining release of K+ to the cytoplasm, E2(K+)2 → E1 + 2K+. At normal physiological concentrations of extracellular Na+ of 140 mM, it is to be expected that binding of Na+ to the allosteric site would be nearly saturated. Its purpose would seem to be simply to optimize the enzyme’s ion pumping rate under its normal physiological conditions. Based on published crystal structures, a possible location of the allosteric site is within a cleft between the α- and β-subunits of the enzyme.

Short cationic antimicrobial peptides bind to human alpha-1 acid glycoprotein with no implications for thein vitrobioactivity

Several drugs interact with the major plasma proteins serum albumin and alpha-1 acid glycoprotein. Such binding may be either beneficial or disadvantageous from a pharmacokinetic perspective. In the present paper, we investigate the thermodynamics involved in the binding of a series of promising cationic antimicrobial peptides to the alpha-1 acid glycoprotein using isothermal titration calorimetry. The drug-like peptides are able to effectively destroy multiresistant bacterial strains, and members of this peptide class are currently in clinical phase II trials. Similar peptides, in a previous study, have been shown to bind to serum albumin resulting in a 10-fold reduction in the peptides ability to kill bacteria in vitro. Here, it is shown that the peptides also are ligands for alpha-1 glycoprotein with moderate binding affinities. The binding mode is investigated in detail using molecular docking, which maps the interaction to sub-pockets I, II and III of the binding site. Despite this interaction, protein binding is shown to have little or no effect on the ability of the peptides to kill bacteria in vitro, either at normal physiological or acute phase concentrations. The results show that although the peptides interact with the binding pocket of alpha-1 acid glycoprotein, the low stoichiometric binding ratio ensures that the interaction is not an obstacle for further development of these promising peptides as antimicrobial therapies.

Hydrogen sulfide induces heme oxygenase-1 in human kidney cells

Hydrogen sulfide (H2S) has been shown to have a potential protective role in a number of disease states including diabetes and various kidney disorders; however, the mechanisms involved are still unclear. The aim of this study was to investigate if H2S effects the expression of the antioxidant enzyme heme oxygenase-1 (HO-1) in human kidney cells. Human mesangial cells and human podocytes were cultured at normal physiological glucose concentration (5.5 mM) and then treated with different H2S donors for a 24-h period. Protein was then extracted from the cells, and the expression levels of HO-1 determined by Western blotting. There was a significant increase in HO-1 expression after treatment with the H2S donors in both mesangial and podocyte cells. These results suggest that H2S has a role in the regulation of HO-1 expression, and the ability to upregulate this antioxidant enzyme maybe a potential mechanism by which H2S exerts its protective effects.

Effects of thyroid hormone on islet β cell function among type 2 diabetics with normal thyroid function

To explore the effects of thyroid hormone on islet β cell function among type 2 diabetics with normal thyroid function. A total of 266 type 2 diabetics with normal thyroid function were recruited. Their clinical, biochemical parameters and thyroid related hormones were measured. And acute insulin response (AIR) was examined by arginine stimulating test. The serum levels of triiodothyronine (T3) ((1.49 ± 0.03), (1.59 ± 0.03), (1.70 ± 0.04) µmol/L) and free triiodothyronine (FT3) ((4.01 ± 0.08), (4.37 ± 0.09), (4.44 ± 0.07) pmol/L) were significantly different among tertile groups of AIR (both P < 0.01) while those of thyroxine (T4), free thyroxine (FT4) and thyroid stimulating hormone (TSH) showed no significant differences among tertile groups of AIR (all P > 0.05). A significant positive correlation existed between lnAIR and T3, FT3 (r = 0.303, 0.302, both P < 0.01). T4 and FT4 were not correlated with lnAIR (both P>0.05). AIR was significantly different among tertile groups of T3 ((2.38 ± 0. 12), (2.64 ± 0.12) and (3.03 ± 0.10) mU/L) and FT3 ((2.34 ± 0.11), (2.69 ± 0.13), (2.99 ± 0.10) mU/L, P < 0.01). AIR were not significantly different among tertile groups of T4, FT4 and TSH (all P > 0.05). Multivariate linear regression demonstrated that T3 and FT3 level were independently associated with AIR (β = 0.686, 95% CI 0.289-0.884, P = 0.001, β = 0.296, 95% CI 0.125-0.467, P = 0.01). Significant positive associations exist between serum T3, FT3 and AIR in type 2 diabetics with normal thyroid function. Serum T3 and FT3 may be the independent risk factors of predicting islet beta cell function in type 2 diabetics with normal thyroid function. However, it remains to be determined whether or not normal physiological concentrations of T3 and FT3 are protective factors for islet β cell functions among type 2 diabetics.

Novel S-Nitrosothiols Have Potential Therapeutic Uses for Cystic Fibrosis

Cystic fibrosis (CF) is a multisystem disease associated with mutations in the gene that encodes the CF transmembrane conductance regulatory (CFTR) protein. The majority of wild-type CFTR and virtually all mutant ΔF508 CFTR are degraded before reaching the cell surface. Certain agents and conditions that increase expression and maturation of CFTR enable the protein to function at the cell surface. We and several research groups have reported that S-nitrosoglutathione (GSNO), a class of endogenous S-nitrosothiols, increases the maturation and function of CFTR in human airway epithelial cells. S-nitrosothiols (SNOs) are endogenous molecules with several cell signaling effects and potential relevance to human lung disease. SNOs are normally present in the human airway and have beneficial effects on lung function. Biochemical evidence suggests that SNOs act on post-translational protein modifications through mechanisms involving S-nitrosylation reactions. S-nitrosylation reactions are increasingly recognized to represent metabolically regulated cell signaling processes. Airway epithelial S-nitrosylation signaling disorders have been observed in a range of diseases, including CF. SNO levels are low in CF patients and normal physiological concentrations are effective in increasing CFTR maturation. The mechanisms by which SNOs improve CFTR expression appear to be novel. However, the precise mechanisms by which SNOs exert their beneficial effects are poorly understood. In the near future, we expect to identify the novel mechanisms by which SNO augments CFTR maturation. This information will be critical for optimizing the design and dosing of SNOs that might be used as CFTR corrector therapies in clinical trials.

In vitro fibrillogenesis of collagen type I in varying ionic and pH conditions

Collagen is the most abundant protein in the human body, and has primary roles in the formation of tendons, cartilage and bone, it provides mechanical strength to skin and indeed almost every organ and muscle is associated with a layer of collagen. It is thus a key component of the extracellular matrix. Here we have studied the in vitro fibrillogenesis of acetic acid-soluble collagen type I under physiological and varying non-physiological conditions by TEM from negatively stained specimens. At pH 2.5 the collagen heterotrimer remains soluble at increasing buffer concentrations and in the presence of increasing NaCl concentrations. At pH 4.5 molecular aggregates form at low NaCl concentrations, but at higher NaCl concentrations fibrils with a diffuse ~11nm banding are formed. At pH 7.0, initial molecular aggregates form at low NaCl concentrations that progressively form characteristic ~67nm D-banded collagen fibrils at intermediate NaCl concentrations that cluster to form thicker multi-fibril D-banded fibres in higher NaCl concentrations. By contrast, increasing concentrations of sodium phosphate at pH 7.0 leads to the formation of flexuous, unbanded fibrils at higher concentrations from the initial, loosely aggregated form of collagen. At higher pHs, the formation of D-banded fibrils is less efficient, particularly at pH 9.0. Thus at neutral pH, the presence of chloride anions, rather than sodium cations, is required for the production of D-banded collagen fibrils; higher than normal physiological chloride concentrations in the form of NaCl or Tris·HCl at neutral pH, but not phosphate buffer, can also lead to the efficient in vitro formation of D-banded collagen fibrils.

Electrode interfaces switchable by physical and chemical signals for biosensing, biofuel, and biocomputing applications

This review outlines advances in designing modified electrodes with switchable properties controlled by various physical and chemical signals. Irradiation of the modified electrode surfaces with various light signals, changing the temperature of the electrolyte solution, application of a magnetic field or electrical potentials, changing the pH of the solutions, and addition of chemical/biochemical substrates were used to change reversibly the electrode activity. The increasing complexity in the signal processing was achieved by integration of the switchable electrode interfaces with biomolecular information processing systems mimicking Boolean logic operations, thus allowing activation and inhibition of electrochemical processes on demand by complex combinations of biochemical signals. The systems reviewed range from simple chemical compositions to complex mixtures modeling biological fluids, where the signal substrates were added at normal physiological and elevated pathological concentrations. The switchable electrode interfaces are considered for future biomedical applications where the electrode properties will be modulated by the biomarker concentrations reflecting physiological conditions.

Is Endogenous GLP-1 the Only Important Enhancer of Glucose-Induced Insulin Secretion in Type 2 Diabetes?

It has been known for over a century that the small intestinal mucosa contains a substance(s) which decreases glucosuria in diabetic patients (1), with the term “incretin” (i.e., the assumption that intestinally derived substances are involved in regulation of postprandial insulin secretion) being first coined by La Barre (2) in 1932. Proof of the incretin concept came with the observation that orally administered glucose gave rise to a much larger insulin response than when the same amount of glucose was given intravenously (3,4). Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the major incretin hormones in humans (5,6). Together, they account for up to 70% of postprandial insulin secretion in healthy subjects (7). In individuals with type 2 diabetes, however, the incretin effect is severely impaired (8). It is now widely accepted that this is largely the result of reductions in the insulinotropic activity of both incretin hormones (9,10), although in some patients an impaired secretion of GLP-1 may also contribute (11). A classic method for establishing the role of a given peptide is to infuse it in such a way as to mimic normal physiological plasma concentrations. By giving GLP-1 and GIP by variable infusion rate to copy their normal postprandial plasma profiles, Vilsboll et al. (12) demonstrated that both incretin hormones contribute almost equally to the incretin effect in healthy subjects. However, …

Enzyme-Based Logic Analysis of Biomarkers at Physiological Concentrations: AND Gate with Double-Sigmoid “Filter” Response

We report the first realization of a biomolecular AND gate function with double-sigmoid response (sigmoid in both inputs). Two enzyme biomarker inputs activate the gate output signal, which can then be used as indicating liver injury, but only when both of these inputs have elevated pathophysiological concentrations, effectively corresponding to logic-1 of the binary gate functioning. At lower, normal physiological concentrations, defined as logic-0 inputs, the liver-injury output levels are not obtained. High-quality gate functioning in handling of various sources of noise, on time scales of relevance to potential applications, is enabled by utilizing "filtering" effected by a simple added biocatalytic process. The resulting gate response is sigmoid in both inputs when proper system parameters are chosen, and the gate properties are theoretically analyzed within a model devised to evaluate its noise-handling properties.

Protection from intracellular oxidative stress by cytoglobin in normal and cancerous oesophageal cells.

Cytoglobin is an intracellular globin of unknown function that is expressed mostly in cells of a myofibroblast lineage. Possible functions of cytoglobin include buffering of intracellular oxygen and detoxification of reactive oxygen species. Previous work in our laboratory has demonstrated that cytoglobin affords protection from oxidant-induced DNA damage when over expressed in vitro, but the importance of this in more physiologically relevant models of disease is unknown. Cytoglobin is a candidate for the tylosis with oesophageal cancer gene, and its expression is strongly down-regulated in non-cancerous oesophageal biopsies from patients with TOC compared with normal biopsies. Therefore, oesophageal cells provide an ideal experimental model to test our hypothesis that downregulation of cytoglobin expression sensitises cells to the damaging effects of reactive oxygen species, particularly oxidative DNA damage, and that this could potentially contribute to the TOC phenotype. In the current study, we tested this hypothesis by manipulating cytoglobin expression in both normal and oesophageal cancer cell lines, which have normal physiological and no expression of cytoglobin respectively. Our results show that, in agreement with previous findings, over expression of cytoglobin in cancer cell lines afforded protection from chemically-induced oxidative stress but this was only observed at non-physiological concentrations of cytoglobin. In addition, down regulation of cytoglobin in normal oesophageal cells had no effect on their sensitivity to oxidative stress as assessed by a number of end points. We therefore conclude that normal physiological concentrations of cytoglobin do not offer cytoprotection from reactive oxygen species, at least in the current experimental model.

Biomolecular Filters for Improved Separation of Output Signals in Enzyme Logic Systems Applied to Biomedical Analysis

Biomolecular logic systems processing biochemical input signals and producing "digital" outputs in the form of YES/NO were developed for analysis of physiological conditions characteristic of liver injury, soft tissue injury, and abdominal trauma. Injury biomarkers were used as input signals for activating the logic systems. Their normal physiological concentrations were defined as logic-0 level, while their pathologically elevated concentrations were defined as logic-1 values. Since the input concentrations applied as logic 0 and 1 values were not sufficiently different, the output signals being at low and high values (0, 1 outputs) were separated with a short gap making their discrimination difficult. Coupled enzymatic reactions functioning as a biomolecular signal processing system with a built-in filter property were developed. The filter process involves a partial back-conversion of the optical-output-signal-yielding product, but only at its low concentrations, thus allowing the proper discrimination between 0 and 1 output values.

In Vitro Assessment of Tobacco Smoke Toxicity at the BBB: Do Antioxidant Supplements Have a Protective Role?

BackgroundTobacco smoke (TS) contains highly reactive oxygen species (such as hydrogen peroxide, peroxynitrite, etc), which cause oxidative damage in vascular tissue and may exacerbate inflammatory events leading to the blood-brain barrier damage (BBBD) which accompanies the development of a variety of neurological disorders. Smokers often have elevated leukocyte counts (primarily neutrophils and monocytes), and significant decreases in plasma alpha-tocopherol (vitamin E) and ascorbic acid (vitamin C) levels due to increased anti-oxidative mobilization in response to oxidative stress evoked by TS. For this purpose, using static culture systems and a well-established dynamic in vitro BBB model (DIV-BBB) we tested the hypothesis that antioxidant vitamin supplementation (E and/or C) can protect the BBB during exposure to whole soluble TS.ResultsTS exacerbates inflammatory events and leads to endothelial overexpression of vascular adhesion molecules (VCAM-1, P-selectin and E-selectin), release of pro-inflammatory cytokines (TNF-α and IL-6) and nitric oxide (NO), release and activation of matrix metalloproteinases (MMP-2 and MMP-9), monocytic maturation into macrophages, and adhesion to the vascular endothelium. Furthermore, TS altered the normal glucose metabolic behaviour of in vitro BBB capillaries and caused a period of transient anaerobic respiration to meet the cellular bioenergetic demand. Pre-treatment with antioxidant vitamins (C and/or E) effectively reduced the pro-inflammatory activity associated with TS, protecting the viability and functions of the BBB.ConclusionOur results have shown that loss of endothelial viability as well as BBB function and integrity caused by TS exposure can be prevented or at least reduced by normal physiologic concentrations of antioxidant vitamins in vitro.

Oxidative stress in earthworms short- and long-term exposed to highly Hg-contaminated soils

Exposure to mercury is often assessed by the measurement of molecular and biochemical antioxidant defences against an excessive production of reactive oxygen species. Here we examined some selected biomarkers of oxidative stress in the earthworm Lumbricus terrestris short- (2 d) and long-term (44 d) exposed to Hg-contaminated soils (up to 1287 mg/kg dry wt). This level of Hg exposure did not cause earthworm mortality, however it yielded organisms to a situation of oxidative stress which was evidenced by the time-dependent responses of biomarkers. The reduced to oxidized glutathione ratio was a sensitive and early biomarker of Hg exposure, although the glutathione reductase activity back returned their normal physiological concentrations. Metallothioneins and total glutathione seemed to have a significant role in reducing Hg-induced oxidative stress when exposure to Hg prolonged up to 44 d. We combined biomarker responses into an integrate biomarker index which positively correlated with the Hg concentrations measured in the postmitochondrial fraction of the earthworm muscle, and with the available Hg fraction in soil. Current results suggest that glutathione redox cycle can be a complementary tool in the exposure and effect assessment of Hg-polluted soils.

The assessment of potentially interfering metabolites and dietary components in blood using an osmotic glucose sensor based on the concanavalin A–dextran affinity assay

Continuous surveillance of blood glucose is a prerogative of maintaining a tight glycaemic control in people suffering from diabetes mellitus. Implantable sensor technology offers the potential of conducting direct long term continuous glucose measurements, but current size restrictions and operational challenges have limited their applications. The osmotic sensor utilises diffusion to create a hydrostatic pressure that is independent of sensor operation and power consumption. This permits ultra-low power architectures to be realized with a minimal start-up time in a package suitable for miniaturization. In contrast, osmotic sensors suffer from the inability of their membranes to discriminate between different constituents in blood or the interstitial fluid that are of comparable size to glucose. By implementing an affinity assay based on the competitive bonding between concanavalin A and dextran, the selectivity of the membrane can be transferred to the glucose specific recognition of the affinity assay. The osmotic effect from the physiological levels of several key metabolites and nutritional components has been addressed identifying in particular ethanol, lactate and amino acids as potential interfering constituents. Both ascorbic acid and mannose would have a normal physiological concentration that is too low to be detected. The studies shows that an osmotic glucose sensor equipped with the con A–dextran affinity assay, is able to filter out potential interfering constituents present in blood, plasma and the interstitial fluid yet retaining a pressure that is proportional to glucose only.

Fibrinogen concentrate for management of bleeding

Fibrinogen concentrate for management of bleeding

Development and validation of 14 human serum protein assays on the Roche cobas® c 501

Many laboratories rely on dedicated nephelometers and turbidimeters for the measurement of serum proteins. There are, however, a number of chemistry analyzers that offer open channel configurations for end-user applications. We developed and validated 14 human serum protein assays (α(1)-antitrypsin, α(2)-macroglobulin, albumin, apolipoproteins AI and B, complement components 3 and 4, haptoglobin, immunoglobulins A, G, and M, orosomucoid, transferrin, and transthyretin) on the Roche cobas(®) c 501. We obtained excellent precision at low, normal, and high physiologic concentrations of each protein (within-run imprecision CVs ≤2.5%, total imprecision CVs ≤3.6%). Linearity for each method was within 5% of the expected value throughout the calibration range, and method comparison studies to commercial assays from Roche or Siemens were in good agreement (r>0.975). We observed no significant interference from bilirubin (up to 414 mg/l), hemoglobin (up to 8.9 g/l), triglyceride (up to 28 g/l), or rheumatoid factor (up to 3,930 IU/ml). Calibration was stable for at least 14 days. The instrument's small reaction cell allowed us to conserve nearly 60% of our specimen and reagent volume compared with our previous system. These newly developed assays provide precise and accurate results with high throughput, but without the associated cost of a dedicated instrument.

1436 SIMVASTATIN INHIBITS THE GROWTH OF ANDROGEN-SENSITIVE AND ANDROGEN-INDEPENDENT CELLS IN VITRO

You have accessJournal of UrologyProstate Cancer: Basic Research VIII1 Apr 20101436 SIMVASTATIN INHIBITS THE GROWTH OF ANDROGEN-SENSITIVE AND ANDROGEN-INDEPENDENT CELLS IN VITRO Elizabeth Masko, Lionel L. Banez, Salvatore V. Pizzo, and Stephen J. Freedland Elizabeth MaskoElizabeth Masko More articles by this author , Lionel L. BanezLionel L. Banez More articles by this author , Salvatore V. PizzoSalvatore V. Pizzo More articles by this author , and Stephen J. FreedlandStephen J. Freedland More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1129AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Statins, the most widely used family of drugs, inhibit the enzyme HMG-coA reductase and effectively lower serum cholesterol at concentrations ranging from 3.2-8.8 ng/ml (∼7-20nM). Statins may be better therapy rather than chemoprevention for prostate cancer (PCa), as recent data suggest statins do not prevent PCa, but instead may prevent its progression. Many studies examined the role of statins in vitro as treatment of various PCa cell lines, but typical doses were well above normal physiological range (2-200μM). METHODS A total of three androgen-sensitive (LAPC-4, LNCaP, and CWR22) and two androgen-independent (PC-3 and DU145) cell lines were treated with varying concentrations of simvastatin (100-1000nM) for 1-5 days. Cell proliferation was measured by MTS assay, and IC50 calculated using BioDataFit 1.02. Cell viability was determined using the androgen-sensitive LAPC-4 and androgen-independent PC-3 cell lines via Trypan Blue exclusion assay. All experiments were completed in triplicate, and results represent the mean value for each treatment. RESULTS For all cell lines, simvastatin inhibited cell growth within the nanomolar range. More specifically, the IC50 for the androgen-sensitive cell lines ranged 250-500nM after 3 days and lower doses after 5 days. As for the androgen-independent cell lines, the 3-day IC50 for DU145 was 628nM. Of all the cell lines, PC-3 was the most sensitive with a 3-day IC50 of 75nM. In the cell viability assays, although simvastatin inhibited growth at concentrations less than 250nM in LAPC-4 and 75nM treatment in PC-3 (as measured by MTS assay), cell death was not induced until higher concentrations. In LAPC-4, cell viability was reduced by 28% at 500nM simvastatin, and by 92% at 750nM simvastatin. In the PC-3 cell line, cell death was not induced until 100nM simvastatin. CONCLUSIONS In this study, simvastatin inhibited cell growth of androgen-sensitive and androgen-independent PCa cell lines in vitro at concentrations slightly higher than normal physiological concentrations, but still dramatically less than most currently published studies. While the results are promising, there are many mechanisms through which statins may inhibit PCa growth that could not be tested in this in vitro model (i.e. lowering serum cholesterol levels, reduced systemicinflammation, anti-angiogenesis, etc.). Thus, statins remain an exciting agent for further testing in PCa therapy and further studies are needed to determine the exact mechanisms of action for statins on PCa cells. Durham, NC© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e553-e554 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Elizabeth Masko More articles by this author Lionel L. Banez More articles by this author Salvatore V. Pizzo More articles by this author Stephen J. Freedland More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...