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Gerd Geisslinger

Publications and source records attributed to Gerd Geisslinger.

At least 19 recordsLinked to original sources
PubMed2006

Pharmacological and histopathological characterization of a hyperalgesia model induced by freeze lesion.

Induction of a freeze lesion in human skin is an experimental model of hyperalgesia that allows assessing the antihyperalgesic effects of traditional non-steroidal anti-inflammatory drugs (NSAIDs). We have investigated whether this model is also sensitive to selective cyclooxygenase (COX)-2 inhibitors and have characterized morphological substrates of the generated hyperalgesia in the skin. In eight healthy subjects, a freeze lesion was induced and mechanical pain thresholds (MPT) were tested for 5h following administration of the non-selective COX inhibitor diclofenac (75mg), the COX-2-selective inhibitor parecoxib (40mg) or placebo in a randomized, double-blind cross-over study. In five additional healthy subjects, biopsies were taken from normal skin and the area of freezing injury. Induction of the freeze lesion resulted in hyperalgesia expressed by a decrease of MPT after 24h. Diclofenac and parecoxib, but not placebo, statistically significantly elevated MPT. Histochemical and Western blot analyses of skin biopsies revealed a strong upregulation of COX-2, a slight decrease of COX-1 and activation of nuclear factor kappa B (NF-kappaB) in the area of the freezing injury. These findings indicate that the freeze lesion model is sensitive to NSAIDs including selective COX-2 inhibitors, and that NF-kappaB-dependent COX-2 upregulation contributes to the hyperalgesia in this model.

Adult↗
PubMed2006

Impaired acute and inflammatory nociception in mice lacking the p50 subunit of NF-kappaB.

The transcription factor NF-kappaB is thought to play an essential role in inflammatory processes and pain. However, the in vivo function of individual NF-kappaB subunits in the development and processing of nociceptive responses is not clarified. In this study we investigated the role of the p50 subunit of NF-kappaB in models of acute and persistent nociception using NF-kappaB p50(-/-) mice. We found that these mice showed impaired basal responses to mechanical as well as thermal noxious stimulation in the dynamic plantar as well as the hot plate test, respectively, in comparison with wild-type mice. In the formalin test we observed a decreased nociceptive behavior in the first and the second phase in NF-kappaB p50(-/-) mice. In a model of persistent inflammatory hyperalgesia these mice also showed a reduced hyperalgesia to a thermal stimulus, which was in accordance with a lower cyclooxygenase-2 expression in the spinal cord after peripheral inflammatory stimulation. Taken together, our data indicate that the p50 subunit of NF-kappaB is of importance in acute and persistent inflammatory pain. The participation to persistent pain might rely on activation of NF-kappaB by inflammatory stimuli while the contribution to acute pain responses might be related to constitutive NF-kappaB activity in neurons of the nociceptive system.

Animals↗
PubMed2006

GTP cyclohydrolase and tetrahydrobiopterin regulate pain sensitivity and persistence.

We report that GTP cyclohydrolase (GCH1), the rate-limiting enzyme for tetrahydrobiopterin (BH4) synthesis, is a key modulator of peripheral neuropathic and inflammatory pain. BH4 is an essential cofactor for catecholamine, serotonin and nitric oxide production. After axonal injury, concentrations of BH4 rose in primary sensory neurons, owing to upregulation of GCH1. After peripheral inflammation, BH4 also increased in dorsal root ganglia (DRGs), owing to enhanced GCH1 enzyme activity. Inhibiting this de novo BH4 synthesis in rats attenuated neuropathic and inflammatory pain and prevented nerve injury-evoked excess nitric oxide production in the DRG, whereas administering BH4 intrathecally exacerbated pain. In humans, a haplotype of the GCH1 gene (population frequency 15.4%) was significantly associated with less pain following diskectomy for persistent radicular low back pain. Healthy individuals homozygous for this haplotype exhibited reduced experimental pain sensitivity, and forskolin-stimulated immortalized leukocytes from haplotype carriers upregulated GCH1 less than did controls. BH4 is therefore an intrinsic regulator of pain sensitivity and chronicity, and the GTP cyclohydrolase haplotype is a marker for these traits.

Adult↗
PubMed2006

LC-MS/MS-analysis of sphingosine-1-phosphate and related compounds in plasma samples.

Sphingosine-1-phosphate (S1P) and related compounds are important signaling molecules and are normal constituents of human plasma. So far, only a few methods exist for their determination specifically in plasma demanding radioactive agents, more or less time consuming extraction or derivatization procedures. Here, we describe a very simple, reliable, sensitive standard-addition method for the simultaneous determination of S1P, sphingosine (SPH), sphinganine (SAPH) and sphinganine-1-phosphate (SA1P) in human and rat plasma samples. After methanol precipitation of plasma samples the supernatants were directly assessed by liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS). HPLC analysis was done under gradient conditions using a C18 reversed phase column. The lower limit of quantification (LLOQ) was <10.2, <4.6, <1.9 and 0.57ng/ml for S1P, SPH, SAPH and SA1P, respectively. Variations in accuracy and intraday and interday precision were <15% over the range of calibration. All analytes were normal constituents both in human and rat plasma although the SA1P concentrations in a few rat plasma samples were below the lower limit of quantification. This validated method is suitable to generate new pharmacological findings by monitoring plasma concentrations of S1P and related compounds especially when low amounts of plasma samples are present (e.g. plasma samples from rodents).

Animals↗
PubMed2006

Is mPGES-1 a promising target for pain therapy?

Cyclooxygenase (COX) inhibitors are widely used analgesic and anti-inflammatory drugs. Owing to undesirable effects caused by unselective COX inhibitors and selective COX-2 inhibitors, microsomal prostaglandin E(2) synthase-1 has been considered as an alternative target for the development of analgesic drugs. However, recent findings question the usefulness of this terminal synthase as a promising drug target for pain therapy.

Animals↗
PubMed2006

Cyclooxygenase-2 (COX-2)-independent anticarcinogenic effects of selective COX-2 inhibitors.

Nonsteroidal antiinflammatory drugs (NSAIDs) appear to reduce the risk of developing cancer. One mechanism through which NSAIDs act to reduce carcinogenesis is to inhibit the activity of cyclooxygenase-2 (COX-2), an enzyme that is overexpressed in various cancer tissues. Overexpression of COX-2 increases cell proliferation and inhibits apoptosis. However, selective COX-2 inhibitors can also act through COX-independent mechanisms. In this review, we describe the COX-2-independent molecular targets of these COX-2 inhibitors and discuss how these targets may be involved in the anticarcinogenic activities of these selective COX-2 inhibitors. We also compare the concentrations of these inhibitors used in in vitro and in vivo experiments and discuss the implications of the in vitro studies for clinical management of cancer with these drugs.

Adenomatous Polyposis Coli↗
PubMed2006

The glutamate transporter GLAST is involved in spinal nociceptive processing.

GLAST and GLT-1 are the most abundant glutamate transporters in the CNS and protect neurons from glutamate neurotoxicity. Here, we investigated the role of GLAST in spinal nociceptive processing. GLAST protein expression was not altered after treatment of rats with either formalin or zymosan. Surprisingly, knock-down of GLAST in the spinal cord using antisense-oligonucleotides decreased glutamate concentrations in cerebrospinal fluid (CSF) and reduced the nociceptive behaviour in the rat formalin assay. However, it did not influence thermal hyperalgesia in the zymosan-induced paw inflammation model indicating that GLAST is associated with spontaneous rather than inflammatory nociception. Mechanisms that might explain the decreased response in the formalin assay may include compensatory activation of other glutamate transporters, inhibition of glutamate release or disturbance of glutamate recycling. In conclusion, these data suggest that inhibition of GLAST expression in the spinal cord reduces excitatory synaptic activity and thereby spontaneous responses after nociceptive stimulation of the paw.

Amino Acid Transport System X-AG↗
PubMed2006

Apoptotic cells promote macrophage survival by releasing the antiapoptotic mediator sphingosine-1-phosphate.

Programmed cell death is vital for a number of pathophysiologic settings. Apoptotic cells are rapidly engulfed by phagocytes (ie, macrophages), which in turn acquire an anti-inflammatory phenotype known as alternative activation or the M2-type. Here we show that interaction of apoptotic cells with macrophages attenuates cell death pathways in the latter. Protection of human macrophages required phosphoinositide 3-kinase (PI3K), extracellular signal-regulated kinase 1/2 (ERK1/2), and Ca2+ signaling, and correlated with Bcl-X(L) and Bcl-2 up-regulation as well as Ser136-Bad phosphorylation. Unexpectedly, neither phagocytosis nor binding of apoptotic debris to the phagocyte was necessary to induce protection. Surprisingly, apoptotic cells released sphingosine-1-phosphate (S1P), mainly derived from sphingosine kinase 2, as a survival messenger. This points to an active role of apoptotic cells in preventing cell destruction in their neighborhood, with implications for innate immunity and inflammation.

Animals↗
PubMed2006

Evidence of COX-2 independent induction of apoptosis and cell cycle block in human colon carcinoma cells after S- or R-ibuprofen treatment.

Ibuprofen belongs to the 2-aryl propionic-acid derivatives and consists of two enantiomers, of which S-ibuprofen is a potent cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) inhibitor whereas the R-enantiomer is two to three orders of magnitude less potent to inhibit cyclooxygenases. Beside its positive effects on inflammation and pain several animal studies have shown that ibuprofen also inhibits tumor initiation and proliferation but the molecular mechanisms are not fully understood. To investigate to which extent the antiproliferative effect of ibuprofen depends on COX-inhibition we tested both enantiomers in different human colon carcinoma cell lines (HCA-7 express COX-1, COX-2 and produce high prostaglandin E2 level; HCT-15 express only COX-1 and produce nearly no prostaglandin E2). S- and R-ibuprofen reduced concentration dependently cell survival in both cell lines to a similar extent and caused a G0/G1 phase block as well as apoptosis. The cell cycle block was accompanied by a down regulation of cyclin A and B and an increase of the cell cycle inhibitory protein p27Kip-1. HCA-7 cells were less sensitive against the antiproliferative effects of ibuprofen enantiomers which was probably due to lower ibuprofen concentrations in this cell type. Also in the nude mice model both enantiomers inhibited tumor growth of HCA-7 and HCT-15 xenografts to a similar extent. However, in mice about 54% of R-ibuprofen was unidirectionally inverted to S-ibuprofen, thus the observed antitumorigenic effect of R-ibuprofen in vivo cannot solely be assigned to this enantiomer. In conclusion our data indicate that S- and R-ibuprofen show similar antiproliferative effects in human colon carcinoma cell lines irrespective of its COX-inhibiting potencies.

Animals↗
PubMed2006

High sensitive determination of sufentanil in human plasma of parturients and neonates following patient-controlled epidural analgesia (PCEA).

A validated method for the determination of sufentanil in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is described. Sufentanil was extracted from human plasma with solid-phase-extraction using deuterated sufentanil, [(2)H(5)]-sufentanil, as internal standard. Sufentanil and the internal standard were determined with an API 4000 tandem mass spectrometer equipped with a Turbo-V-Source operating in positive ESI mode on an Alltima HP HILIC straight phase column. The method showed a lower limit of quantification of 0.25 pg/ml (12.5 fg on column). The applicability of the method is shown in a clinical study, in which levels of sufentanil in plasma of parturients and arterial umbilical plasma of their neonates following patient-controlled epidural analgesia (PCEA) under several regimen treatments was analyzed.

Analgesia, Epidural↗
PubMed2006

Different COX-independent effects of the COX-2 inhibitors etoricoxib and lumiracoxib.

Etoricoxib and lumiracoxib are both highly selective COX-2 inhibitors. This drug class has recently been linked to severe side effects in particular within the cardiovascular system. The underlying signal transduction pathway is not clarified at the moment but different COX-independent mechanisms might contribute to wanted and unwanted effects of these drugs. Here, we investigated COX-2-independent effects of etoricoxib and lumiracoxib. Both inhibited the activation of the transcription factor NF-kappaB, but had no effects on activation of the AP-1 subunits c-jun and c-fos. On the other hand, activation of the transcription factor CREB was dose-dependently inhibited only by etoricoxib. Together with NF-kappaB-inhibition this might contribute to the reduced protein expression of the pro-inflammatory proteins COX-2 and iNOS. In contrast, lumiracoxib did not influence CREB activation and showed no effect on iNOS and COX-2 protein expression. In conclusion, we showed that etoricoxib and lumiracoxib have different COX-independent mechanisms which may be of clinical relevance.

Animals↗
PubMed2006

Cardiovascular risk with cyclooxygenase inhibitors: general problem with substance specific differences?

Randomised clinical trials and observational studies have shown an increased risk of myocardial infarction, stroke, hypertension and heart failure during treatment with cyclooxygenase inhibitors. Adverse cardiovascular effects occurred mainly, but not exclusively, in patients with concomitant risk factors. Cyclooxygenase inhibitors cause complex changes in renal, vascular and cardiac prostanoid profiles thereby increasing vascular resistance and fluid retention. The incidence of cardiovascular adverse events tends to increase with the daily dose and total exposure time. A comparison of individual selective and unselective cyclooxygenase inhibitors suggests substance-specific differences, which may depend on differences in pharmacokinetic parameters or inhibitory potency and may be contributed by prostaglandin-independent effects. Diagnostic markers such as N-terminal pro brain natriuretic peptide (NT-proBNP) or high-sensitive C-reactive protein might help in the early identification of patients at risk, thus avoiding the occurrence of serious cardiovascular toxicity.

Cardiovascular Diseases↗
PubMed2006

Evidence for morphine-independent central nervous opioid effects after administration of codeine: contribution of other codeine metabolites.

OBJECTIVE: Our objective was to investigate whether codeine or one of its metabolites contributes substantially to central nervous effects independent from the cytochrome P450 (CYP) 2D6-mediated O-demethylation to morphine. METHODS: After oral administration of codeine, plasma concentrations of codeine and its metabolites, as well as pupil size as a measure of central nervous effects, were measured in 11 healthy volunteers representing poor, intermediate, extensive, and ultrarapid metabolizers for CYP2D6. Subsequently, the observed plasma morphine concentrations were mimicked by use of computerized morphine infusion, and the miotic effects were compared with those observed after codeine administration. The contribution of codeine, codeine-6-glucuronide, norcodeine, morphine, morphine-6-glucuronide, and normorphine to the miotic effects was analyzed by means of pharmacokinetic-pharmacodynamic modeling. RESULTS: The areas under the curve of the miotic effects after codeine were 1.7 +/- 2 times greater than after morphine (P <0.01). This contrasted to similar or even lower morphine concentrations after codeine than after morphine (area under the curve ratio, 0.5 +/- 0.4; P =.21). A pharmacokinetic-pharmacodynamic fit of the miotic effects by use of morphine as the only active moiety was most significantly (P <.0001) improved when codeine-6-glucuronide as a second active moiety was added. CONCLUSION: CYP2D6-dependent formation of morphine does not explain exclusively the central nervous effects of codeine. Codeine-6-glucuronide is the most likely additional active moiety.

Adult↗
PubMed2006

Modulation of the central nervous effects of levomethadone by genetic polymorphisms potentially affecting its metabolism, distribution, and drug action.

AIM: Our aim was to judge the importance of candidate pharmacogenetic modulators of the central nervous effects of levomethadone by both magnitude of the modulatory effect and frequency of the mutation to assess the utility of genotyping for clinical levomethadone therapy in a random sample of subjects that, by distribution of genotypes, resembled the clinical setting. METHODS: Candidate pharmacogenetic modulators were polymorphisms reported to be of functional consequence and therefore potentially important for metabolism, distribution, or pharmacodynamic action of levomethadone, consisting of genes coding for cytochrome P450 (CYP) 2B6 and 3A, as well as 1A2, 2C8, 2C9, 2C19, and 2D6, for P-glycoprotein (ABCB1), and for mu-opioid receptors (OPRM1). The central nervous effects of levomethadone were investigated by means of measuring pupil size in a random sample of 51 healthy volunteers for 9 hours after oral administration of 0.075 mg/kg levomethadone. Plasma concentrations of levomethadone and its metabolites were assessed concomitantly, and to judge the role of metabolites, the affinities of levomethadone and its metabolites at mu-opioid receptors were estimated by use of displacement of the selective mu-opioid receptor agonist [(3)H]-DAMGO ((3)H-[D-Ala(2),N-MePhe(4),Gly-ol(5)]-enkephalin). RESULTS: Pupil size decreased to -41.8% +/- 9.6% from baseline at 3.5 +/- 1.1 hours after levomethadone administration. Miosis was still manifest to a lower degree (-25.1% +/- 12.3%) at the end of the observation period. In carriers of the variant 118G allele (118A>G single-nucleotide polymorphism) of the mu-opioid receptor gene (OPRM1), levomethadone had a 1.74 times (95% confidence interval, 1.4-2.2 times) lower miotic potency (P < .001) as compared with noncarriers (concentration at half-maximum effects, 52.3 nmol/L; 95% confidence interval, 36.7-66.2 nmol/L). The maximum percent decrease in pupil diameter from baseline was 44.9% +/- 7.6%, 33% +/- 6.5%, and 24% +/- 6.9% for carriers of the OPRM1 118AA, AG, and GG genotypes, respectively (P < .001 for AG and GG versus wild type, without significant differences between AG and GG). Other candidate polymorphisms in the ABCB1 or in CYP genes had no significant influence on the effects of levomethadone, either because of lack of functional consequences or because of their low allelic frequency. The metabolites of levomethadone did not contribute to the effects as indicated by low metabolite plasma concentrations and their 120- to 1300-fold lower affinities at mu-opioid receptors as compared with levomethadone. CONCLUSIONS: Among polymorphisms in OPRM1, ABCB1, and CYP genes previously associated with functional consequences in a different context, the most important pharmacogenetic factor modulating the short-term effects of levomethadone is a polymorphism (OPRM1 118A>G) affecting mu-opioid receptors.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2006

The cyclooxygenase 2 genetic variant -765G>C does not modulate the effects of celecoxib on prostaglandin E2 production.

OBJECTIVE: Our objective was to assess the role of the reportedly functional PTGS2 (prostaglandin-endoperoxide synthase 2/cyclooxygenase [COX] 2) promoter mutation -765G>C for the COX-2-inhibiting effects of celecoxib. METHODS: Twenty healthy carriers of the -765GG genotype and -765CC genotype (n = 10 each) received 200 mg of celecoxib orally. Blood samples were drawn at baseline and at 1, 3, 6, 9, and 24 hours after administration. Plasma concentrations of celecoxib and concentrations of prostaglandin E(2) (PGE(2)) produced by peripheral blood monocytes stimulated ex vivo with bacterial lipopolysaccharide (LPS) were analyzed by liquid chromatography-tandem mass spectrometry. Expression of COX-2 messenger ribonucleic acid and protein expression with and without LPS stimulation were analyzed by real-time polymerase chain reaction and Western blotting, respectively. RESULTS: LPS induced PGE(2) production (P < .001), and celecoxib reduced PGE(2) production from 19.3 +/- 7.2 ng/mL at baseline to 7.4 +/- 4.8 ng/mL at 1 hour (P < .001). The effect of celecoxib lasted for 9 hours (repeated-measures ANOVA, P .28). LPS up-regulated COX-2 messenger ribonucleic acid expression (P = .016) but was independent of genotype (P = .36). COX-2 protein expression was similar for both -765G>C genotypes (P = .63). CONCLUSION: The PTGS2 -765G>C single-nucleotide polymorphism does not modulate COX-2 inhibitory effects of celecoxib as assessed by an ex vivo whole blood assay. Thus the results indicate the need for further investigation toward PTGS2 pharmacogenetics-based prescription of celecoxib.

Adult↗
PubMed2006

Inhibition of prostaglandin E2 synthesis by SC-560 is independent of cyclooxygenase 1 inhibition.

Prostaglandin E2 (PGE2) produced by cyclooxygenase-2 (COX-2) and microsomal prostaglandin E2 synthase-1 (mPGES-1) plays an important role in the pathophysiology of inflammation, pain, and fever. We investigated the actions of TNFalpha toward stimulation of PGE2 synthesis in primary spinal cord neurons. TNFalpha induced COX-2 and mPGES-1 expression in neurons, followed by formation of PGE2, which was blocked by a selective COX-2 inhibitor. Surprisingly, the "selective COX-1" inhibitor SC-560 completely inhibited TNFalpha-induced PGE2 synthesis in neurons at nanomolar concentrations. Moreover, SC-560 inhibited PGE2 and thromboxane A2 synthesis in human monocytes and platelets with IC50 of 1.8 nM and 2.5 nM, respectively. SC-560 treatment neither altered TNFalpha-induced COX-2 or mPGES-1 expression nor did the addition of the calcium ionophore A23187 or arachidonic acid reverse the inhibition by SC-560. Moreover, no influence of SC-560 on PGE2 synthase activities or PGE2 transport was seen. Most importantly, SC-560 blocked TNFalpha-induced PGE2 synthesis in COX-1-deficient spinal cord neurons, demonstrating a COX-1-independent inhibition of PGE2 synthesis. Although SC-560 inhibited LPS-induced PGE2 synthesis in neurons and RAW264.7 macrophages in whole cell assays, no inhibition was observed in lysates of the same cells. Taken together our data demonstrate that SC-560 acts at least in some cell types as an unselective COX inhibitor despite its selectivity toward COX-1 under cell-free conditions.

Animals↗