Interpreting the Benefit and Risk Data in Between-Drug Comparisons: Illustration of the Challenges Using the Example of Mefenamic Acid versus Ibuprofen.

Evidence-based pain therapy should rely on precisely defined and personalized criteria. This includes balancing the benefits and risks not only of single drugs but often requires complex between-drug comparisons. Non-steroidal anti-inflammatory drugs (NSAIDs) have been available for several decades and their use is described in an abundance of guidelines. Most of these guidelines recommend that 'the selection of a particular NSAID should be based on the benefit-risk balance for each patient'. However, head-to-head studies are often lacking or of poor quality, reflecting the lower standards for clinical research and regulatory approval at the time. The inconsistency of approved indications between countries due to national applications adds to the complexity. Finally, a fading research interest once drugs become generic points to a general deficit in the post-marketing evaluation of medicines. Far from claiming completeness, this narrative review aimed to illustrate the challenges that physicians encounter when trying to balance benefits and risks in a situation of incomplete and inconsistent data on longstanding treatment concepts. Ibuprofen and mefenamic acid, the most frequently sold NSAIDs in Austria, serve as examples. The illustrated principles are, however, not specific to these drugs and are generalizable to any comparison of older drugs in daily clinical practice.

Dysfunction of the Blood-Brain Barrier-A Key Step in Neurodegeneration and Dementia.

The vascular endothelium in the brain is an essential part of the blood-brain-barrier (BBB) because of its very tight structure to secure a functional and molecular separation of the brain from the rest of the body and to protect neurons from pathogens and toxins. Impaired transport of metabolites across the BBB due to its increasing dysfunction affects brain health and cognitive functioning, thus providing a starting point of neurodegenerative diseases. The term "cerebral metabolic syndrome" is proposed to highlight the importance of lifestyle factors in neurodegeneration and to describe the impact of increasing BBB dysfunction on neurodegeneration and dementia, especially in elderly patients. If untreated, the cerebral metabolic syndrome may evolve into dementia. Due to the high energy demand of the brain, impaired glucose transport across the BBB via glucose transporters as GLUT1 renders the brain increasingly susceptible to neurodegeneration. Apoptotic processes are further supported by the lack of essential metabolites of the phosphocholine synthesis. In Alzheimer's disease (AD), inflammatory and infectious processes at the BBB increase the dysfunction and might be pace-making events. At this point, the potentially highly relevant role of the thrombocytic amyloid precursor protein (APP) in endothelial inflammation of the BBB is discussed. Chronic inflammatory processes of the BBB transmitted to an increasing number of brain areas might cause a lasting build-up of spreading, pore-forming ß-amyloid fragments explaining the dramatic progression of the disease. In the view of the essential requirement of an early diagnosis to investigate and implement causal therapeutic strategies against dementia, brain imaging methods are of great importance. Therefore, status and opportunities in the field of diagnostic imaging of the living human brain will be portrayed, comprising diverse techniques such as positron emissions tomography (PET) and functional magnetic resonance imaging (fMRI) to uncover the patterns of atrophy, protein deposits, hypometabolism, and molecular as well as functional alterations in AD.

Fragment-based solid-phase assembly of oligonucleotide conjugates with peptide and polyethylene glycol ligands.

Ligand conjugation to oligonucleotides is an attractive strategy for enhancing the therapeutic potential of antisense and siRNA agents by inferring properties such as improved cellular uptake or better pharmacokinetic properties. Disulfide linkages enable dissociation of ligands and oligonucleotides in reducing environments found in endosomal compartments after cellular uptake. Solution-phase fragment coupling procedures for producing oligonucleotide conjugates are often tedious, produce moderate yields and reaction byproducts are frequently difficult to remove. We have developed an improved method for solid-phase coupling of ligands to oligonucleotides via disulfides directly after solid-phase synthesis. A 2'-thiol introduced using a modified nucleotide building block was orthogonally deprotected on the controlled pore glass solid support with N-butylphosphine. Oligolysine peptides and a short monodisperse ethylene glycol chain were successfully coupled to the deprotected thiol. Cleavage from the resin and full removal of oligonucleotide protection groups were achieved using methanolic ammonia. After standard desalting, and without further purification, homogenous conjugates were obtained as demonstrated by HPLC, gel electrophoresis, and mass spectrometry. The attachment of both amphiphilic and cationic ligands proves the versatility of the conjugation procedure. An antisense oligonucleotide conjugate with hexalysine showed pronounced gene silencing in a cell culture tumor model in the absence of a transfection reagent and the corresponding ethylene glycol conjugate resulted in down regulation of the target gene to nearly 50% after naked application.

Concise postsynthetic preparation of oligonucleotide-oligopeptide conjugates through facile disulfide bond formation.

BACKGROUND: Despite recent advances, major hurdles still need to be cleared for widespread application of therapeutic antisense technologies. In particular, pharmacokinetic properties and efficient cellular uptake need to be improved through chemical derivatization or bioconjugation. RESULTS: The 2'-O-thioethylene nucleotide building block affords easy implementation into standard oligonucleotide synthesis protocols and was used to attach oligolysine chains to phosphodiester oligonucleotides by direct reaction with S-sulfonate protected peptides. Efficient gene silencing was induced in a cell culture model after transfection reagent-free application of the conjugates. CONCLUSION: A facile optimized procedure for generating oligonucleotide-peptide conjugates was established. The attachment of short basic peptides via a labile linker is sufficient to enhance membrane permeability of oligonucleotides and result in successful gene silencing.

Inflammation Modulates RLIP76/RALBP1 Electrophile-Glutathione Conjugate Transporter and Housekeeping Genes in Human Blood-Brain Barrier Endothelial Cells.

Endothelial cells are often present at inflammation sites. This is the case of endothelial cells of the blood-brain barrier (BBB) of patients afflicted with neurodegenerative disorders such as Alzheimer's, Parkinson's, or multiple sclerosis, as well as in cases of bacterial meningitis, trauma, or tumor-associated ischemia. Inflammation is a known modulator of gene expression through the activation of transcription factors, mostly NF-κB. RLIP76 (a.k.a. RALBP1), an ATP-dependent transporter of electrophile-glutathione conjugates, modulates BBB permeability through the regulation of tight junction function, cell adhesion, and exocytosis. Genes and pathways regulated by RLIP76 are transcriptional targets of tumor necrosis factor alpha (TNF-α) pro-inflammatory molecule, suggesting that RLIP76 may also be an inflammation target. To assess the effects of TNF-α on RLIP76, we faced the problem of choosing reference genes impervious to TNF-α. Since such genes were not known in human BBB endothelial cells, we subjected these to TNF-α, and measured by quantitative RT-PCR the expression of housekeeping genes commonly used as reference genes. We find most to be modulated, and analysis of several inflammation datasets as well as a metaanalysis of more than 5000 human tissue samples encompassing more than 300 cell types and diseases show that no single housekeeping gene may be used as a reference gene. Using three different algorithms, however, we uncovered a reference geneset impervious to TNF-α, and show for the first time that RLIP76 expression is induced by TNF-α and follows the induction kinetics of inflammation markers, suggesting that inflammation can influence RLIP76 expression at the BBB. We also show that MRP1 (a.k.a. ABCC1), another electrophile-glutathione transporter, is not modulated in the same cells and conditions, indicating that RLIP76 regulation by TNF-α is not a general property of glutathione transporters. The reference geneset uncovered herein should aid in future gene expression studies in inflammatory conditions of the BBB.

Quality control and stability studies with the monoclonal antibody, trastuzumab: application of 1D- vs. 2D-gel electrophoresis.

Recombinant monoclonal antibodies (rmAbs) are medicinal products obtained by rDNA technology. Consequently, like other biopharmaceuticals, they require the extensive and rigorous characterization of the quality attributes, such as identity, structural integrity, purity and stability. The aim of this work was to study the suitability of gel electrophoresis for the assessment of charge heterogeneity, post-translational modifications and the stability of the therapeutic, recombinant monoclonal antibody, trastuzumab. One-dimensional, SDS-PAGE, under reducing and non-reducing conditions, and two-dimensional gel electrophoresis were used for the determination of molecular mass (Mr), the isoelectric point (pI), charge-related isoform patterns and the stability of trastuzumab, subjected to stressed degradation and long-term conditions. For the assessment of the influence of glycosylation in the charge heterogeneity pattern of trastuzumab, an enzymatic deglycosylation study has been performed using N-glycosidase F and sialidase, whereas carboxypeptidase B was used for the lysine truncation study. Experimental data documented that 1D and 2D gel electrophoresis represent fast and easy methods to evaluate the quality of biological medicinal products. Important stability parameters, such as the protein aggregation, can be assessed, as well.

Transport rankings of non-steroidal antiinflammatory drugs across blood-brain barrier in vitro models.

The aim of this work was to conduct a comprehensive study about the transport properties of NSAIDs across the blood-brain barrier (BBB) in vitro. Transport studies with celecoxib, diclofenac, ibuprofen, meloxicam, piroxicam and tenoxicam were accomplished across Transwell models based on cell line PBMEC/C1-2, ECV304 or primary rat brain endothelial cells. Single as well as group substance studies were carried out. In group studies substance group compositions, transport medium and serum content were varied, transport inhibitors verapamil and probenecid were added. Resulted permeability coefficients were compared and normalized to internal standards diazepam and carboxyfluorescein. Transport rankings of NSAIDs across each model were obtained. Single substance studies showed similar rankings as corresponding group studies across PBMEC/C1-2 or ECV304 cell layers. Serum content, glioma conditioned medium and inhibitors probenecid and verapamil influenced resulted permeability significantly. Basic differences of transport properties of the investigated NSAIDs were similar comparing all three in vitro BBB models. Different substance combinations in the group studies and addition of probenecid and verapamil suggested that transporter proteins are involved in the transport of every tested NSAID. Results especially underlined the importance of same experimental conditions (transport medium, serum content, species origin, cell line) for proper data comparison.

Exploring the polyamine regulatory site of the NMDA receptor: a parallel synthesis approach.

The elongated structures of polyamine inverse agonists such as 1,12-diaminododecane (N12N) and 5-(4-aminobutyl)-2-thiopheneoctanamine (N4T8N) lend themselves to a combinatorial chemistry approach to explore a potential polyamine pharmacophore at the NMDA receptor. Herein we describe more than 100 new analogues of N4T8N obtained by breaking up the long octanamine arm into a dipeptide chain of equivalent length. Solid-phase parallel synthesis based on cross-linked polystyrene and a Wang anchor allowed the low-scale preparation of four small libraries based on the combination of two amino acid residues (out of Gly, Leu, Phe, Lys, phenylglycine, Tyr, Trp, His, and Arg). The obtained compounds were tested as modulators of [(3) H]MK-801 binding to rat brain membranes and of NMDA-induced currents in cultured rat hippocampal neurons. Compounds with two aromatic residues acted as binding inhibitors (inverse agonists). Compounds with two Lys residues acted as binding stimulators (agonists) and had stimulatory and inhibitory effects on NMDA-induced currents, depending on the holding potential. High sensitivity of binding inhibition to spermine was conferred by a Tyr residue, whereas a His residue favored high potency at acidic pH.

Formaldehyde-a key monad of the biomolecular system.

Experiments will be presented and reviewed to support the hypothesis that the intrinsic reactivity of formaldehyde may lead to the formation of a rather comprehensive set of defined biomolecules, including D-glucose, thus fostering concepts of evolution considering the existence of a premetabolic system as a primordial step in the generation of life.

Rapid determination of diclofenac in pharmaceutical formulations by capillary zone electrophoresis.

Capillary electrophoresis is competitive to HPLC and other chromatographic methods, predominantly when charged analytes have to be separated. The time of analysis can be reduced by the use of very short capillaries applying a high voltage. In most instruments which are commercially available the so-called 'short end' of the capillary can be used for separation, leading to very rapid separations. In this contribution we want to demonstrate this approach by using Diclofenac Sodium as an analyte.

Impact of the pharmaceutical sciences on health care: a reflection over the past 50 years.

During the last century, particularly the latter half, spectacular progress has been made in improving the health and longevity of people. The reasons are many, but the development of medicines has played a critical role. This report documents and reflects on the impressive contribution that those working in the pharmaceutical sciences have made to healthcare over the past 50 years. It is divided into six sections (drug discovery; absorption, distribution, metabolism, and excretion; pharmacokinetics and pharmacodynamics; drug formulation; drug regulation; and drug utilization), each describing key contributions that have been made in the progression of medicines, from conception to use. A common thread throughout is the application of translational science to the improvement of drug discovery, development, and therapeutic application. Each section has been coordinated by a leading scientist who was asked, after consulting widely with many colleagues across the globe, to identify "The five most influential ideas/concepts/developments introduced by 'pharmaceutical scientists' (in their field) over the past 50 years?" Although one cannot predict where the important breakthroughs will come in the future to meet the unmet medical needs, the evidence presented in this report should leave no doubt that those engaged in the pharmaceutical sciences will continue to make their contributions heavily felt.

A Standard Protocol for the Calibration of Capillary Electrophoresis (CE) Equipment.

Calibration of complex analytical systems is always a difficult task. Nevertheless, a suitable approach has to be designed before the systems can be introduced into routine analysis. In literature, many methods have been described for the purpose of calibrating such systems, but only a few of them deal with capillary elctrophoresis. Here, we want to demonstrate a general approach to how the calibration of this type of analytical instrument becomes feasible.

Comparison of two-dimensional gel electrophoresis patterns and MALDI-TOF MS analysis of therapeutic recombinant monoclonal antibodies trastuzumab and rituximab.

The principal objective of this study was the evaluation of two-dimensional gel electrophoresis (2-DE) in combination with MALDI-TOF MS, after tryptic digest with regard to suitability for qualitative characterization and identification of therapeutic recombinant monoclonal antibodies trastuzumab and rituximab. Moreover, the impact of post-translational modifications of these glycoproteins on the electrophoresis behavior has been evaluated. 1-D SDS-PAGE, in reducing and non-reducing conditions, and 2-DE were used for the assessment of M(r) and the monitorization of deglycosylation efficiency. In addition, 2-DE was used for the determination of pIs. 2-DE gels revealed characteristic glycoprotein migration behavior, highly complex spot pattern, typical for recombinant monoclonal antibodies. N-linked oligosaccharides were released with PNGase F; enzymatic desialination was studied with sialidase and carboxypeptidase B was used for the study of lysine truncation. Peptide spots resolved in 2-DE gels were in gel tryptically digested, resulting peptides were subjected to MALDI-TOF MS analysis and peptide mass fingerprinting (PMF) has been used for the identity confirmation of both monoclonal antibodies.

2-DE and MALDI-TOF-MS analysis of therapeutic fusion protein abatacept.

2-DE and MALDI-TOF MS are useful techniques for the quality evaluation of medicinal products derived from recombinant DNA technology. The principal objective of this study has been to evaluate the suitability of 2-DE in combination with MALDI-TOF MS for the quality study of the therapeutic recombinant protein, abatacept. 1-DE SDS-PAGE, under reducing and nonreducing conditions, and 2-DE analysis were used for the assessment of M(r) , pI, and enzymatic deglycosylation efficiency of abatacept. 2-DE allowed the assessment of product identity, purity, charge heterogeneity, isoform pattern, and post-translational modifications. Furthermore, optimization of the deglycosylation procedure, charge heterogeneity, and sample preparation for the subsequent MALDI-TOF MS analysis has been addressed. PMF analysis allowed rapid identity confirmation of abatacept.

Effects of NMDA receptor modulators on a blood-brain barrier in vitro model.

Changes of the functionality of the blood-brain barrier (BBB) have been reported in the context of several brain related diseases such as multiple sclerosis, epilepsy, Alzheimer's disease and stroke. Several publications indicated the presence and functionality of the NMDA receptor (NMDAR) at the brain endothelium and a possible involvement of the NMDAR in the above-mentioned diseases. Recently, it was shown that the application of the NMDAR antagonist MK801 can block several adverse effects at the BBB in vitro, but also that MK801 can significantly change the proteome of brain endothelial cells without simultaneous stimulation of NMDAR by glutamate. Based on these reports we investigated if NMDAR antagonists MK801 and D-APV can affect the intracellular calcium level (Ca²âºi) of an in vitro BBB model based on human cell line ECV304 on their own and compared these results to effects mediated by NMDAR agonists glutamate and NMDA. Treatment of ECV304 cells for 30 min with glutamate resulted in no significant change of Ca²âºi. On the contrary, application of NMDA and NMDAR antagonists D-APV and MK801 led to a significant and concentration dependent decrease of Ca²âºi. Further studies revealed that glutamate was able to decrease the transendothelial electrical resistance (TEER) of the BBB in vitro model, whereas NMDA and D-APV were able to increase TEER. Analysis of the protein expression levels of tight junctional molecules ZO-1 and occludin showed a complex regulation after application of NMDAR modulators. In summary, it was shown that NMDAR antagonists can alter BBB key properties in vitro on their own. Moreover, although qPCR results confirmed the presence of NMDA receptor subunits NR1, NR2A, NR2B and NR2C, membrane binding studies failed to prove the typical plasma membrane localization and functionality in human BBB cell line ECV304.

Off-target effects related to the phosphorothioate modification of nucleic acids.

Phosphorothioate antisense oligonucleotides have been widely used in clinical studies for rational sequence-specific gene silencing. However, several sequence-unspecific off-target effects have been recently described for this compound class. In contrast to siRNA-mediated knockdown of the same gene, the bcl-2-targeted oblimersen (Genasense, G3139) downregulates a number of proteins involved in apoptotic resistance and several glycolytic enzymes in 607B human melanoma cells. Regardless of their target, phosphorothioate-modified antisense and siRNA compounds, but not oligonucleotides with a phosphodiester backbone, resulted in a similar impact on the proteome. Unspecifically downregulated proteins include cancer markers involved in apoptotic resistance and endoplasmatic reticulum (ER) stress such as the 78 kDa glucose regulated protein (GRP 78), protein disulfide isomerase A3 (PDIA3, GRP 58), calumenin, and galectin-1, as well as the glycolytic enzymes triose phosphate isomerase, glyceraldehyde phosphodehydrogenase, and phosphoglycerate mutase. The depletion of the glycolytic enzymes is reflected by a decrease in L-lactate production, indicating a partial reversal of the Warburg effect. Compared with other phosphorothioate oligonucleotides, oblimersen generally led to a more pronounced effect both in terms of the number of influenced proteins and the extent of downregulation, suggesting a synergistic effect of Bcl-2 downregulation.

Blood-brain barrier cell line PBMEC/C1-2 possesses functionally active P-glycoprotein.

The blood-brain barrier (BBB) maintains the homeostasis between the central nervous system and the blood circulation. One of the main efflux transporter proteins at the BBB is P-glycoprotein (P-gP) also known as ABCB1 or MDR1. Due to the important role of P-gP for the transport barrier function of the BBB, the presence and functionality of P-gP was investigated in porcine cell line PBMEC/C1-2. Presence of P-gP was confirmed on the protein level by western blotting and immunofluorescence microscopy as well as on the mRNA level by qPCR. Functional assessment was accomplished by an established 96-well uptake assay using Rhodamine 123 and Doxorubicin as P-gP substrates and Verapamil as moderate P-gP inhibitor. In this regard, fluorescence microscopy confirmed a significant higher uptake of Rhodamine 123 into PBMEC/C1-2 cells when preincubated with Verapamil. Finally, knock-down of P-gP by antisense oligonucleotides revealed an increase of Rhodamine 123 uptake indicating decreased P-gP functionality. In summary, the presence and functionality of P-gP in the immortalised cell line PBMEC/C1-2 was proven with several techniques and assays. Thus, this cell line could be used for P-gP studies in the context of BBB relevant issues.

A proteomic study reveals unspecific apoptosis induction and reduction of glycolytic enzymes by the phosphorothioate antisense oligonucleotide oblimersen in human melanoma cells.

The question of specificity and the elucidation of the exact molecular mechanism of action of post-transcriptional gene silencing agents are two major challenges for their establishment as therapeutics. A proteomic off-target effect study (2-DE with MS) in combination with DIGE comparing the phosphorothioate antisense oligonucleotide oblimersen (Genasense, G3139) to a Bcl-2-targeting siRNA-sequence on human melanoma cells showed that additional off-target effects contribute to the apoptotic effect of oblimersen. When both oligonucleotides were transfected with lipofectamine 2000, only oblimersen increased apoptosis as determined by annexin staining and caspase activity measurement. In contrast to the highly specific siRNA, the expression level of a number of proteins was found to be altered after oblimersen treatment. Several proteins linked to apoptosis and stress response, among those galectin-1, cofilin-1, GRP78, HSP60, nucleophosmin, and peroxiredoxins, were identified and found to be down-regulated after oblimersen treatment. A down-regulation of enolase-1 and three other glycolytic enzymes indicates a reversion of the cancer-related Warburg effect. The observed effects may be caused by a phosphorothioate mediated blockage of the mitochondrial voltage dependent anion channel (VDAC).

Influence of image-analysis software on quantitation of two-dimensional gel electrophoresis data.

Image analysis of two-dimensional gels is a crucial step in a proteomic workflow and has a direct impact on obtained qualitative and quantitative data. Since the analysis is a complex process and creates large data amounts, the use of a respective software is inevitable. There are only a few papers published addressing the issue of analysis-based variance; therefore, our aim was to highlight the discrepancy of received results when different commercially available image-tools are used for gel analysis especially in terms of comparability of the obtained outcome when the same digital image set is used. A set of six gels (three replicates per group) of real-life samples was created and examined with two different versions of PD-Quest (Bio-Rad) (version 6.1 and its update version 8.0) and with an external image-tool Delta 2D (Decodon) (version 3.6). Replicate groups were analyzed and compared with each other with regard to volume ratios of a group of significantly changed spots. The study points out significant variations among results depending on the software package used, underlining the importance of a careful investigation of post-experimental processes to receive comparable and reliable results.

Oligonucleotide-polyamine conjugates: influence of length and position of 2'-attached polyamines on duplex stability and antisense effect.

Tethering cationic ligands to oligonucleotides results in zwitterionic molecules with often improved target affinity and better cell membrane permeation. Due to the ideal distance between cationic groups, polyamines are perfect counter ions for oligonucleotides. Using an easy and versatile procedure for attaching ligands to the 2'-position, polyamines were conjugated to distinct terminal and internal positions of oligonucleotides. With polyamines attached to terminal nucleosides, the affinity to complementary DNA or RNA strands increased with growing number of cationic amines. Tethering polyamines to an internal nucleoside of wild type DNA oligonucleotides resulted in a considerable decrease in duplex stability, but in phosphorothioates, no significant decrease was detected. Conjugates exhibited progressively higher target downregulation ability with increasing polyamine chain length in a human melanoma cell culture assay.