Flavonoids and fibrate modulate apoE4-induced processing of amyloid precursor protein in neuroblastoma cells.

Introduction: Apolipoprotein (apo) E4, being a major genetic risk factor for Alzheimer's disease (AD), is actively involved in the proteolytic processing of amyloid precursor protein (APP) to amyloid ß (Aß) peptide, the principle constituent of amyloid plaques in Alzheimer Disease (AD) patients. ApoE4 is believed to affect APP processing through intracellular cholesterol homeostasis, whereas lowering the cholesterol level by pharmacological agents has been suggested to reduce Aß production. This study has investigated the effects of hypolipidemic agents fenofibrate, and the flavonoids-naringenin and diosmetin-on apoE4-induced APP processing in rat neuroblastoma cells stably transfected with human wild-type APP 695 (B103-hAPP695wt). Results: B103-hAPP695wt cells were pretreated with different doses of flavonoids and fenofibrate for 1 h prior to apoE4 exposure for 24 h. ApoE4-induced production of intra- and extracellular Aß peptides has been reduced with fenofibrate, naringenin, and diosmetin treatments. Pretreatment with diosmetin has significantly reduced apoE4-induced full-length APP (fl- APP) expression, whereas naringenin and fenofibrate had no effect on it. In addition, the increase in the apoE4-induced secretion of sAPPtotal and sAPPα has been dose-dependently reduced with drug pretreatment. On the other hand, the decrease in the expression of both APP-carboxy terminal fragments (CTF)-α and -ß (generated by the α- or ß-secretase cleavage of APP) by apoE4 was dose-dependently increased in cells pretreated with fenofibrate and naringenin but not diosmetin. Conclusion: Thus, we suggest that fenofibrate, naringenin, and diosmetin treatments can reduce apoE4- induced Aß production by distinct mechanisms that may prove useful in developing drugs for AD patients.

Tigecycline prevents LPS-induced release of pro-inflammatory and apoptotic mediators in neuronal cells.

Pro-inflammatory and pro-apoptotic mediators have been involved in the pathogenesis of neurodegenerative diseases. Tigecycline (Tig), a glycylcycline antibiotic and an analog of Minocycline, is shown to exert anti-inflammatory effects that are distinct from its anti-microbial activity. Its neuroprotective mechanism is unknown. In this study, we investigated the direct protective mechanisms of tigecycline against lipopolysaccharide (LPS)-induced Rat pheochromocytoma (PC12) cells. The results showed that tigecycline significantly attenuated the expression and the release of nuclear factor-kappa beta (NF-κB), tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1ß), as well as nitric oxide (NO) levels in LPS-induced PC12 cells. In addition, tigecycline dose-dependently decreased cytochrome c release and caspase-3 activity. This later finding corroborated the results of decreased pro-apoptotic Bad, and increased anti-apoptotic Bcl-2 protein expression thus, confirming a neuroprotective effect of the drug in differentiated PC12 cells induced with LPS. The findings of our study suggest new targets for tigecycline and support the potential for tigecycline to be investigated as a therapeutic agent for neurodegenerative disorders.

Disposition of ON 01210.Na (Ex-RAD(R)), a novel radioprotectant, in the isolated perfused rat liver: probing metabolic inhibition to increase systemic exposure.

ON 01210.Na (Ex-RAD) is a novel benzyl styryl sulfone analog, developed as a radioprotectant by Onconova Therapeutics Inc. The objectives of this research were to evaluate the hepatobiliary disposition of ON 01210.Na in the isolated perfused rat liver (IPRL) and to determine the effect of coadministration of ethacrynic acid (EA) on the pharmacokinetic profile of ON 01210.Na. EA acid was used as a prototypical inhibitor of glutathione-S-transferase inhibitor. ON 01210.Na was highly bound in IPRL perfusate proteins, and binding was significantly lower in the presence of EA. Dose-escalation studies (bolus dose, target concentrations 10-250 µg/mL) showed that ON 01210.Na followed nonlinear pharmacokinetics with hepatic clearance decreasing from 3.14 to 1.99 mL/min with increasing dose. ON 01210.Na underwent extensive metabolic degradation to its glutathione (GSH) adduct in liver. The GSH metabolite was mainly excreted into the bile. Coadministration of EA (1 mM) significantly inhibited the conversion of ON 01210.Na to its GSH conjugate, resulting in decreased clearance (approx. fivefold lower), and prolonged elimination from the perfusate. These preclinical studies suggest that EA is a potential pharmacoenhancer that can reduce the metabolism of ON 01210.Na in vivo, thereby increasing drug exposure and boosting radioprotective activity.

Pharmacogenomics: assessing educational exposure, confidence in knowledge and training elements of pharmacists.

AIM: This study assessed pharmacist's knowledge and confidence in pharmacogenomics (PGx)-related concepts, and determined their needs with regard to education and training in PGx. METHODS: A cross-sectional survey instrument was sent via postal mail to pharmacists (n = 319) who were randomly selected from the New York State database of licensed pharmacists. Descriptive and bivariate statistics were performed. RESULTS: The response rate was 32% (n = 102). The majority (83%) of respondents had been exposed to basic concepts in genetics, while PGx was not an integral part of their education. Most respondents indicated being somewhat confident in their knowledge of PGx-related concepts. In addition, 64% of respondents reported being interested in attending 1-10 h of continuing education programs in PGx, and 42% of respondents indicated being interested in obtaining a certificate in PGx. CONCLUSION: Educational program development in the format of continuing education or certificate is needed to improve pharmacists' education, confidence and training needs in PGx.

The neuroprotective effect of fisetin in the MPTP model of Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is characterized by excessive deposition of neuritic plaques known as Lewy bodies of which α-synuclein is the major contributor to neuronal death. Both oxidative stress and cytokines signaling have been proposed to play an important role in α-synuclein-induced neuronal death in MPTP and PD-related neuronal cell death. Fisetin, a natural polyphenol, possesses antioxidant, anti-inflammatory, and anti-apoptotic properties. However, the molecular neuroprotective mechanisms of fisetin against MPTP-induced cytotoxicity are still unknown. OBJECTIVE: The present study investigated the inhibitory effect of fisetin on MPTP/MPP+-induced neurotoxicity in PC12 cells. METHODS: Cells were pretreated with varying concentrations of fisetin prior exposure to MPTP/MPP+. Cell viability and apoptosis were investigated using MTT assay and DNA fragmentation. The expression and release of transcription factor, pro-inflammatory cytokines, and apoptotic mediators were assessed using western blot analysis and ELISA. RESULTS: Results showed that a pre-treatment with fisetin before exposure to MPTP/MPP+ significantly decreased MPTP/MPP+-induced cytotoxicity and cell death probably by decreasing α-synuclein expression. Mechanisms study showed that fisetin has the potential to inhibit several apoptotic and inflammatory pathways, which play important roles in the initiation and progression of PD. CONCLUSIONS: Altogether, these observations indicate that fisetin is capable of attenuating α-synuclein levels and promoting neuroprotective effects, meanwhile also present some insights into the potential signaling pathways that are involved. Thus, these findings support the role of natural polyphenols in preventive and/or complementary therapies for neurodegenerative diseases.

Protective effect of diosmin on LPS-induced apoptosis in PC12 cells and inhibition of TNF-α expression.

Several studies have demonstrated a link between increased pro-inflammatory mediators and apoptosis in neurodegenerative diseases. It has been reported that lipopolysaccharide (LPS) induces apoptosis mostly through the production of TNF-α. In this study, we investigated the possible protective and anti-inflammatory mechanisms of diosmin, a natural flavone glycoside, on LPS-induced PC12 cells death through inhibition of TNF-α production. PC12 Cells were pretreated with diosmin for 2h prior to LPS treatment for 48 h to assess PC12 cells viability, TNF-α expression, and cell death mechanisms. Diosmin significantly increased cells survival and suppressed LPS-induced TNF-α in a concentration-dependent manner. Diosmin also significantly reduced the DNA fragmentation of LPS-induced cells, and its anti-apoptotic effect was confirmed by the decrease in the expression of pro-apoptotic protein Bad and the increase in the expression of anti-apoptotic protein Bcl-2 on Western blot analysis. Furthermore, diosmin inhibited LPS-induced caspase-3 activation further confirming its anti-apoptotic effects. This is the first study to report the anti-inflammatory and anti-apoptotic effects of diosmin via inhibition of TNF-α and a caspase-dependent pathway in neuronal PC12 cells. These results support the potential for diosmin to be investigated as a potential agent for the treatment of neurodegenerative diseases.

Silodosin: a selective alpha1A-adrenergic receptor antagonist for the treatment of benign prostatic hyperplasia.

BACKGROUND: Silodosin is a new alpha(1)-adrenergic receptor antagonist that is selective for the alpha(1A)-adrenergic receptor. It was approved by the US Food and Drug Administration (FDA) in 2008 for the treatment of lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH). OBJECTIVE: This article reviews the pharmacology, pharmacokinetics, clinical efficacy, adverse effects, drug interactions, and dosage and administration of silodosin in adult male patients with BPH. METHODS: A search of MEDLINE (1950-October 8, 2009), International Pharmaceutical Abstracts (1970-October 8, 2009), and the Iowa Drug Information Service database (1966-October 8, 2009) was conducted using the terms silodosin, KMD-3213, benign prostatic hyperplasia, and alpha(1)-adrenergic receptor antagonist. Reports of research and review articles published in English were identified and evaluated, and the bibliographies of these articles were reviewed for additional relevant publications. A search of the FDA Web site was performed, and abstracts and posters presented at scientific meetings of the American Urological Association were reviewed. RESULTS: By antagonizing alpha(1A)-adrenergic receptors in the prostate and urethra, silodosin causes smooth muscle relaxation in the LUT. Silodosin has greater affinity for the alpha(1A)-adrenergic receptor than for the alpha(1B)-adrenergic receptor (by a factor of 583), minimizing the propensity for blood pressure-related adverse effects mediated by alpha(1B) blockade. In 3 controlled clinical studies in patients with BPH-related LUTS (1 published; 2 presented in the prescribing information and published in a pooled analysis), patients receiving silodosin at a total daily dose of 8 mg had significant improvements in the International Prostate Symptom Score (IPSS) and maximum urinary flow rate (Q(max)) compared with those receiving placebo (both, P < 0.05). The most commonly reported adverse effect was abnormal or retrograde ejaculation (>22%), and the incidence of orthostatic hypotension was low (<3%). CONCLUSIONS: In the small number of clinical trials reviewed, silodosin was associated with significant reductions in IPSS and Q(max) compared with placebo. To determine whether silodosin's selectivity for the alpha(1A)-adrenergic receptor translates into a clinical advantage relative to other available agents, long-term studies evaluating the comparative efficacy and tolerability of silodosin and other alpha(1)-blockers (specifically tamsulosin) are necessary.