PubMed Health⌕ Search

Biomedical subjects

Gerd Geisslinger

Publications and source records attributed to Gerd Geisslinger.

At least 37 records · Page 2Linked to original sources
PubMed2006

The mu-opioid receptor gene polymorphism 118A>G depletes alfentanil-induced analgesia and protects against respiratory depression in homozygous carriers.

AIM: To investigate whether OPRM1 118A>G polymorphism affects analgesic and respiratory depressive effects of alfentanil and assess its role for the therapeutic range of alfentanil. METHODS: In an open-label, single-occasion design, 10 non-carriers, four heterozygous and six homozygous carriers of the variant OPRM1 118G allele received a computerized infusion of alfentanil to achieve target effect-site concentrations of 0, 33.33, 66.67 and 100 ng/ml. At each concentration level, analgesia was assessed by means of electrically and chemically induced pain, and respiratory depression was quantified by hypercapnic challenge and breathing frequency. RESULTS: The relationship between the percent change of tolerance to electrical stimuli and measured alfentanil concentrations, described by power models, was flatter in carriers of the 118G variant allele than in non-carriers, indicating decreased opioid analgesia (P<0.05). For chemically induced pain, a flatter analgesia versus concentration relationship was found only for homozygous carriers of the 118G allele (P<0.05). The relationship between the percent changes in respiratory parameters was significantly flatter (P<0.01) only in homozygous carriers as compared to heterozygous carriers and non-carriers of the 118G allele. Higher alfentanil concentrations were needed in homozygous carriers as compared to wild-type subjects (2-4 times) to produce the same degree of analgesia, whereas 10-12 times higher alfentanil concentrations were needed to produce the same degree of respiratory depression. CONCLUSION: OPRM1 118A>G polymorphism affects both analgesic and respiratory depressive effects of alfentanil. However, while the analgesic effects are already partly decreased in heterozygous carriers, depending on the pain model, the respiratory depressive effects are decreased in homozygous carriers of the variant 118G allele. The therapeutic range of alfentanil was only broadened in homozygous carriers.

Adult↗
PubMed2006

Nimodipine plasma concentration and retinal blood flow in healthy subjects.

PURPOSE: Calcium antagonists are strong vasodilators, and nimodipine is known to improve cerebral blood flow. The purpose of this study was to measure retinal blood flow and nimodipine plasma concentrations during repeated oral dosing. METHODS: In a double-blind, two-way, crossover study, 20 healthy subjects (mean age, 22.8 +/- 3.7 years) underwent examination of retinal perfusion and nimodipine plasma concentrations. In a placebo-controlled fashion, nimodipine was orally administered at a dosage of 30 mg three times a day for two periods of 5 days including a 9-day washout interval. At days 1, 5, 15, and 19, plasma concentrations of nimodipine and retinal perfusion were measured 11 times within 3 hours. Stereoselective analysis of nimodipine plasma concentrations was performed with the use of liquid chromatography-tandem mass spectrometry. Scanning laser Doppler flowmetry was used to measure the microcirculation of the juxtapapillary retina. Perfusion images were evaluated with the automatic full-field evaluation procedure (AFFPIA). RESULTS: Areas under the plasma concentration versus time curves were similar at day 1 and day 5 of nimodipine administration (t test: P = 0.64). Values of C(max) displayed a large interindividual variance and ranged from 0 ng/mL to 57.5 ng/mL. On average, maximum nimodipine plasma concentrations (C(max)) were 16.6 +/- 14.9 ng/mL and 12.0 +/- 10.3 ng/mL at day 1 and day 5, respectively (P = 0.068). They were observed at 81 +/- 50 and at 93 +/- 40 minutes (t(max)) after the administration of nimodipine at day 1 and day 5, respectively (P = 0.43). Retinal microcirculation was greater after nimodipine than after placebo, as reflected in significantly larger areas under the curves of percentage change in blood flow from baseline versus time (P < 0.01). The maximum increase of retinal blood flow from baseline was significantly more pronounced after nimodipine (28.5% +/- 14.4% and 39.6% +/- 21.4% at day 1 and day 5, respectively) than after placebo (20.5% +/- 16.8% and 31.9% +/- 14.6% at day 1 and day 5, respectively; P = 0.032). CONCLUSIONS: Oral nimodipine significantly increases retinal perfusion in healthy subjects.

Administration, Oral↗
PubMed2006

Fatal respiratory depression after multiple intravenous morphine injections.

A 26-year-old female was treated with morphine within the first 2 hours after knee surgery, in an attempt to titrate analgesia. The patient received a total of four intravenous injections of morphine 35 mg in total. Soon after the last injection the patient had adequate pain relief, was in a good clinical state and had adequate blood oxygenation. However, 40 minutes later, the patient had a deep respiratory depression followed by a fatal cardiac arrest. Solving the case in a medico-legal context was possible by applying results of clinical pharmacokinetic research on opioid analgesics, most importantly morphine, to this particular clinical case. This knowledge made it possible to estimate the probable concentrations of morphine at the site of its effect, the brain, during the time of the fatal event, and to show that these concentrations could have produced respiratory depression. We mainly attribute the fatal intoxication of morphine to the lag period needed for the transfer of morphine across the blood-brain barrier. Because of its slow transfer between plasma and the effect site, the CNS effects of morphine are delayed from its plasma concentrations to a clinically relevant degree. Successive injections at short intervals of relatively high amounts of morphine increase the clinical relevance of this delay. The present report demonstrates an important application of clinical pharmacokinetics for explaining clinical observations at a scientific level and transferring theoretical knowledge from clinical pharmacokinetics into daily clinical practice as a basis for rational opioid selection.

Adult↗
PubMed2006

Rapid identification of three functionally relevant polymorphisms in the OATP1B1 transporter gene using Pyrosequencing.

INTRODUCTION: Clinical evidence suggests there are three single nucleotide polymorphisms (SNPs) of the solute carrier organic anion transporter family member B1 (SLCO1B1) gene for which in vivo evidence for a functional relevance for organic anion transporter polypeptides subgroup C (OATP1B1, formerly OATP-C) has been provided. These genetic variants have been shown to lead to altered pharmacokinetics of OATP1B1 substrates, mainly pravastatin, but also the irinotecan metabolite SN-38, estrone-3-sulfate, and estradiol-17beta-glucuronide. The authors therefore developed reliable and quick screening assays to identify the SLCO1B1 SNPs -11187G>A, 388A>G and 521T>C, in order to facilitate the judgment of their clinical role and to identify allelic frequencies of SNPs and haplotypes in a Caucasian random sample. METHODS: Three simplex Pyrosequencing assays were developed and the three selected SLCO1B1 SNPs were screened for in 250 DNA samples from healthy young female and male unrelated volunteers of Caucasian ethnicity. SLCO1B1 haplotypes involving DNA positions -11187, 388 and 521 were identified by in silico haplotyping. RESULTS: A clear identification of the three single nucleotide polymorphisms in the 250 DNA samples was possible and was verified by routine implementation of 40 control samples obtained by conventional sequencing. The frequencies of the variant alleles -11187A, 388G and 521C were 0.09, 0.47 and 0.12, respectively. All observed frequencies of heterozygous of homozygous carriers of SLCO1B1 alleles were in agreement with the Hardy-Weinberg equilibrium. SLCO1B1 haplotypes reportedly associated with altered substrate pharmacokinetics, i.e., SLCO1B1*15B (-11187G/388G/521C) and *17 (-11187A/388G/521C), were found at allelic frequencies of 0.09 and 0.02, respectively. CONCLUSION: The presently developed Pyrosequencing assays allowed for quick and reliable identification of those SLCO1B1 SNPs that had been proposed to cause functional alternations in OATP1B1 with shown consequences for the pharmacokinetics of drugs that are OATP1B1 substrates.

Adult↗
PubMed2006

Pyrosequencing-based screening for genetic polymorphisms in cytochrome P450 2B6 of potential clinical relevance.

OBJECTIVES: Three exonic single nucleotide polymorphisms (SNPs) in the cytochrome P450 2B6 (CYP2B6) gene, 516G>T, 785A>G and 1459C>T, have been described to be associated with functional changes in the CYP2B6 catalytic activity or protein expression. They are therefore of potential clinical importance for drug efficacy and safety of CYP2B6 substrates, in particular of antiretroviral therapy regimes that include efavirenz. Therefore, we aimed at providing genetic screening assays for these three SNPs. METHODS: Simplex Pyrosequencing assays were developed for the selected CYP2B6 SNPs. A total of 273 DNA samples from healthy volunteers of Caucasian ethnicity were genotyped. RESULTS: The presently developed Pyrosequencing assays afford an accurate determination of the three SNPs in the 273 DNA samples. The assays were verified by routine implementation of control samples obtained by conventional sequencing. The frequencies for the variant alleles 516T, 785G and 1459T were 0.22, 0.24 and 0.13, respectively. All genotype frequencies were in agreement with the Hardy-Weinberg equilibrium. CYP2B6 alleles CYP2B6*5A (1459T), CYP2B6*6 (516T/785G) and *7B (516T/785G/1459T) were found at allelic frequencies of 0.12, 0.20 and 0.01. CONCLUSION: The present reliable and quick Pyrosequencing assays afford facilitating future research on the importance of CYP2B6 pharmacogenetics for personalized drug therapy with CYP2B6 substrates.

Adult↗
PubMed2005

Rapid genotyping for relevant CYP1A2 alleles by pyrosequencing.

OBJECTIVE: To develop a rapid and reliable screening method for identifying the relevant cytochrome P450 (CYP) 1A2 alleles CYP1A2*1D (-2467Tdel), *1F (-163A>C), and *1K (-739T>G, -729C>T, -163A>C) that are in linkage disequilibrium with the functionally relevant CYP1A2 polymorphisms and therefore are considered to be predictive for the CYP1A2 phenotype. METHODS: CYP1A2 single nucleotide polymorphisms (SNPs) -2467Tdel, -739T>G, -729C>T, and -163A>C were screened for in 495 healthy Caucasian volunteers using newly developed pyrosequencing duplex and simplex assays. Conventional sequencing of randomly selected samples served as quality control. RESULTS: Frequencies were 7.9% for CYP1A2*1D, 31.8% for *1F, and 0.4% for *1K. The observed distribution of homozygous and heterozygous carriers of the alleles corresponded to the predicted one according to the Hardy-Weinberg law. It also corresponded to reported allelic frequencies from Caucasians but differed significantly from the distribution seen in other ethnicities. The most frequent haplotype was -2467T/-739T/-729C/-163A (allelic frequency 61.6%), followed by -2467T/-739T/-729C/-163C (30.5%), -2467Tdel/-739T/-729C/-163A (5.1%), -2467Tdel/-739G/-729C/-163A (1.2%), and -2467Tdel/-739T/-729C/-163C (1.1%). Complete linkage disequilibrium (value of D' nearly 1) existed between -2467Tdel, -739T>G, and -729C>T and between -729T>G and -163A>C. CONCLUSIONS: Pyrosequencing facilitates rapid and reliable detection of those CYP1A2 alleles that, based on current knowledge, can be considered predictive for the CYP1A2 phenotype.

Alleles↗
PubMed2005

Downregulation of cytosolic prostaglandin E2 synthase results in decreased nociceptive behavior in rats.

Nociception-evoked prostaglandin E2 (PGE2) release in the spinal cord contributes considerably to the development of hyperalgesia and allodynia. Biosynthesis of PGE2 involves the conversion of arachidonic acid to PGH2 by cyclooxygenases (COXs), followed by an isomerization of PGH2 to PGE2 by PGE2 synthases (PGESs). The roles of COX-1, COX-2, and the inducible microsomal PGES-1 have been studied in models of pain and inflammation. In contrast, in nociceptive processes, very little is known about the role of cytosolic PGES (cPGES), which has been described as being functionally coupled to COX-1. Here we show by in situ hybridization and immunohistological analysis that COX-1 and cPGES are constitutively expressed in neuronal and non-neuronal cells of the dorsal and ventral horns in the spinal cord of adult rats. The protein levels of both enzymes were not regulated by nociceptive stimuli; however, reduction of cPGES in rat spinal cord with intrathecal application of cPGES antisense oligonucleotides reduced the nociceptive behavior in zymosan-evoked thermal hyperalgesia and in the formalin assay. The data indicate that cPGES plays an important role in mediating early responses during spinal nociceptive processing.

Animals↗
PubMed2005

LC-MS/MS-analysis of prostaglandin E2 and D2 in microdialysis samples of rats.

For the determination of prostaglandins in microdialysis samples, usually immunoassays are used. However, these assays may show cross-reactivity among various prostaglandins. To overcome this problem a specific method for the determination of prostaglandin E2 and D2 in rat microdialysis samples by using liquid chromatography-electrospay ionization-tandem mass spectrometry (LC-ESI-MS/MS) is described. Prostaglandin E2 and D2 were extracted from microdialysis samples with liquid-liquid extraction using deuterated prostaglandin D2, [2H4]-PGD2, as internal standard. Subsequently, prostaglandins were separated with a phenomenex Synergi Hydro-RP column and determined with a PE Sciex API 3000 mass spectrometer equipped with a turbo ion spray interface operating in negative ionization mode. The method showed a LLOQ of 25 pg/ml for prostaglandin E2 and 50 pg/ml for prostaglandin D2. The applicability of the method is shown in rat spinal cord microdialysis samples following peripheral nociceptive stimulation.

Animals↗
PubMed2005

Comparative proteomic analysis of the rat spinal cord in inflammatory and neuropathic pain models.

Pathological pain associated either with peripheral tissue damage and inflammation (inflammatory pain) or peripheral nerve injury (neuropathic pain) is characterized by persistent pain hypersensitivity. This hypersensitivity is believed to be mediated by sensitization of nociceptors and spinal dorsal horn neurons leading to hyperalgesia and allodynia. Changes of protein expression and/or phosphorylation are known to contribute to the development of this hyperexcitability of the nociceptive system. In the present study we analyzed protein patterns in the spinal cord following paw inflammation or sciatic nerve injury using two-dimensional (2D) gel electrophoresis combined with MALDI-TOF mass spectrometry. 2D-PAGE revealed nine and five regulated proteins following paw inflammation and sciatic nerve damage, respectively. These regulated proteins had not been identified previously with other methods. There was no overlap of regulated proteins between models except for the small heat shock protein alpha-crystallin, which was decreased in both models. In conclusion, this study illustrates that employment of the proteomic 2D-PAGE approach allows for identification of novel regulated proteins that may be involved in the central sensitization and possibly manifestation of chronic pain.

Animals↗
PubMed2005

Targeting the beta-catenin/APC pathway: a novel mechanism to explain the cyclooxygenase-2-independent anticarcinogenic effects of celecoxib in human colon carcinoma cells.

Celecoxib, a cyclooxygenase-2 (COX-2) selective nonsteroidal anti-inflammatory drug, is a new anticarcinogenic agent. Its antitumor effects depend on the one hand on its COX-2-inhibiting potency, but on the other hand on COX-2-independent mechanisms, which until now have not been fully understood. Here, we investigated whether celecoxib has an impact on the APC/beta-catenin pathway, which has been shown to play a pivotal role in the development of various cancers, especially of the colon. After only 2 h of treatment of human Caco-2 colon carcinoma cells with 100 muM celecoxib, we observed a rapid translocation of beta-catenin from its predominant membrane localization to the cytoplasm. Inhibition of the glycogen-synthase-kinase-3beta (GSK-3beta) by LiCl prevented this celecoxib-induced translocation, suggesting that phosphorylation of beta-catenin by the GSK-3beta kinase was essential for this release. Furthermore, the cytosolic accumulation was accompanied by a rapid increase of beta-catenin in the nuclei, starting already 30 min after celecoxib treatment. The DNA binding activity of beta-catenin time dependently decreased 2 h after celecoxib treatment. After this cellular reorganization, we observed a caspase- and proteasome-dependent degradation of beta-catenin after 8 h of drug incubation. Celecoxib-induced beta-catenin degradation was also observed in various other tumor cell lines (HCT-116, MCF-7, and LNCAP) but was not seen after treatment of Caco-2 cells with either the anticarcinogenic nonsteroidal anti-inflammatory drug R-flurbiprofen or the highly COX-2-selective inhibitor rofecoxib. These findings indicate that the anticarcinogenic effects of celecoxib can be explained, at least partly, by an extensive degradation of beta-catenin in human colon carcinoma cells.

Adenomatous Polyposis Coli Protein↗
PubMed2005

COX-dependent mechanisms involved in the antinociceptive action of NSAIDs at central and peripheral sites.

Despite the diverse chemical structure of aspirin-like drugs, the antinociceptive effect of NSAIDs is mainly due to their common property of inhibiting cyclooxygenases involved in the formation of prostaglandins. Prostaglandins are potent hyperalgesic mediators which modulate multiple sites along the nociceptive pathway and enhance both transduction (peripheral sensitizing effect) and transmission (central sensitizing effect) of nociceptive information. Inhibition of the formation of prostaglandins at peripheral and central sites by NSAIDs thus leads to the normalisation of the increased pain threshold associated with inflammation. The contribution of peripheral and central mechanisms to the overall antinociceptive action of NSAIDs depends on several factors including the location of the targets of drug action, the site of drug delivery and the uptake and distribution to the site of action. The present work reviews the data on the regulation and location of cyclooxygenases at central and peripheral sites of the nociceptive pathway and focuses on the role of COX in the generation and maintenance of pain hypersensitivity. Experimental and clinical evidences are used to evaluate the significance of the peripheral and central antihyperalgesic effects of NSAIDs.

Animals↗
PubMed2005

Induction of apoptosis by R-flurbiprofen in human colon carcinoma cells: involvement of p53.

R-flurbiprofen, a non cyclooxygenase inhibiting non-steroidal anti-inflammatory drug (NSAID), has been found to inhibit tumor growth in various animal models. In vitro experiments have shown that this effect is based on the induction of a cell cycle block and apoptosis. Cell cycle inhibition has been explained by activation of the c-Jun-N-terminal kinase (JNK) and downregulation of cyclin D1 expression. However, the molecular mechanism leading to apoptosis is unknown. Here, we show that treatment of the human colon carcinoma cell line HCT116 with different concentrations of R-flurbiprofen leads to an accumulation of p53 protein which is accompanied by an increase in phosphorylated p53 at serine 15. Mutation of serine 15 to alanine by site directed mutagenesis and overexpression of the mutated p53 gene in HCT116 cells, revealed that these cells are significantly less sensitive to apoptosis induced by R-flurbiprofen than pcDNA control cells, as measured by PARP-cleavage and flow cytometry. By contrast, no difference was detected between HCT116p53ser15ala cells and HCT116 pcDNA cells with respect to induction of a cell cycle block after R-flurbiprofen treatment. Moreover, in nude mice HCT116p53ser15ala overexpressing xenografts were significantly less sensitive to R-flurbiprofen than HCT116 pcDNA control xenografts. In conclusion, we were able to show that induction of apoptosis in HCT116 cells after R-flurbiprofen treatment is at least partly dependent on the tumor suppressor gene p53 and that mutation of p53 at serine 15 impairs the apoptotic potency of R-flurbiprofen.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

The 5-hydroxytryptamine 4 receptor agonist mosapride does not antagonize morphine-induced respiratory depression.

BACKGROUND: On the basis of experiments in rats, serotonin 4 receptor (5-hydroxytryptamine 4 [5-HT4]) agonists have been proposed as a novel therapeutic strategy for the selective treatment of respiratory depression caused by opioids while leaving analgesic effects unaffected. The effects in rats have been seen with the 5-hydroxytryptamine 4a (5-HT4a) agonist BIMU8, which is currently not available for use in humans. METHODS: In a proof-of-applicability study, the clinically recommended dose of 5 mg mosapride, currently the only 5-HT4 agonist available for clinical use, was given in a placebo-controlled manner 3 times daily for 5 days to 12 healthy men and women. During the actual experiments, a further 15 mg mosapride was administered. After baseline measurements of respiratory depression, by use of a carbon dioxide rebreathing method, and of pain, by use of electrical and chemical pain stimuli, 30 mg morphine per 70 kg body weight was administered intravenously within 2 hours. After assessment of respiratory depression and pain, 2 mg naloxone was intravenously administered within 20 minutes, followed by a third assessment of respiratory depression and pain. In ancillary experiments 10 rats received 100 mg/kg mosapride orally or placebo 50 minutes before intraperitoneal injection of 10 mg/kg morphine, followed 20 minutes later by injection of naloxone, and the respiratory frequency was monitored. RESULTS: With placebo coadministration, the slope of the relationship between expiratory volume and CO2 concentration in the inspired air was significantly reduced, from 1.11 +/- 0.46 L/mm Hg CO2 at baseline to 0.39 +/- 0.25 L/mm Hg CO2 at the end of the morphine infusion (P < .001). Coadministration of mosapride had no effect on respiratory depression induced by morphine (slope of 0.39 +/- 0.19 L/mm Hg CO2, P > .7). In contrast, naloxone significantly reversed the slope to 0.78 +/- 0.36 L/mm Hg CO2 (P = .001). Morphine produced significant effects on electrical and chemical pain stimuli, which were partially reversed by naloxone, but mosapride did not affect the analgesic effects of morphine. In rats mosapride similarly failed to prevent a slowing of the breathing frequency after morphine administration but naloxone reversed the respiratory depression. CONCLUSION: Our results show that, with mosapride, opioid-induced respiratory depression cannot be prevented, and because other 5-HT4 agonists are not currently available for clinical use, a cure for opioid-induced respiratory depression as promised by the previous successful experiments in laboratory animals is not yet available in clinical practice.

Adult↗
PubMed2005

Are mu-opioid receptor polymorphisms important for clinical opioid therapy?

Mutations in the mu-opioid receptor--the primary site of action of opioid analgesics--are candidates for the variability of clinical opioid effects. This has been substantiated by recent advances in genetic research. A common mu-opioid receptor polymorphism was associated with higher demands for alfentanil or morphine for pain relief. It also decreased the potency of morphine for pupil constriction and experimental analgesia, but its molecular mechanisms are unclear. Another opioid receptor mutation greatly impaired receptor signalling in vitro, but is very rare. The accumulated evidence provides a solid basis for continuing research that should address the underlying molecular mechanisms and the role and benefits of OPRM1 genotyping for clinical pain therapy.

Analgesics, Opioid↗
PubMed2005

Essential role of the synaptic vesicle protein synapsin II in formalin-induced hyperalgesia and glutamate release in the spinal cord.

The synaptic vesicle protein synapsin II plays an important role in the regulation of neurotransmitter release and synaptic plasticity. Here, we investigated its involvement in the synaptic transmission of nociceptive signals in the spinal cord and the development of pain hypersensitivity. We show that synapsin II is predominantly expressed in terminals and neuronal fibers in superficial laminae of the dorsal horn (laminae I-II). Formalin injection into a mouse hindpaw normally causes an immediate and strong release of glutamate in the dorsal horn. In synapsin II deficient mice this glutamate release is almost completely missing. This is associated with reduced nociceptive behavior in the formalin test and in the zymosan-induced paw inflammation model. In addition, the formalin evoked increase in the number of c-Fos IR neurons is significantly reduced in synapsin II knockout mice. Touch perception and motor coordination, however, are normal indicating that synapsin II deficiency does not generally disrupt sensory and/or motor functions. Antisense-mediated transient knockdown of synapsin II in the spinal cord of adult animals also reduced the nociceptive behavior. As the antisense effect is independent of a potential role of synapsin II during development we suggest that the hypoalgesia in synapsin II deficient mice does involve a direct 'pain-facilitating' effect of synapsin II and is not essentially dependent on potentially occurring developmental alterations. The distinctive role of synapsin II for pain signaling probably results from its specific localization and possibly from a specific control of glutamate release.

Animals↗
PubMed2005

Wound inflammation in diabetic ob/ob mice: functional coupling of prostaglandin biosynthesis to cyclooxygenase-1 activity in diabetes-impaired wound healing.

This study focused on the regulation of prostaglandin (PG) production in diabetes-impaired wound tissue. Cyclooxygenase (COX)-1 and -2 expression and activity were severely dysregulated in chronic wounds of diabetic ob/ob mice. Those wounds were characterized by a reduced expression of COX-1 and the presence of strongly elevated levels of COX-2 when compared with conditions observed in healthy animals. Resolution of the diabetic and impaired wound-healing phenotype by systemic administration of leptin into ob/ob mice increased COX-1 expression in wound margin keratinocytes and decreased COX-2 expression in inner wound areas to levels found in wild-type animals. Notably, improved wound healing was characterized by a marked increase in PGE2/PGD2 biosynthesis that colocalized with induced COX-1 in new tissue at the margin of the wound. COX-2 expression did not significantly contribute to PGE2/PGD2 production in impaired wound tissue. Accordingly, only late wound tissue from SC-560-treated (selective COX-1 inhibitor) but not celecoxib-treated (selective COX-2 inhibitor) ob/ob mice exhibited a severe loss in PGE2, PGD2, and prostacyclin at the wound site, and this change was associated with reduced keratinocyte numbers in the neo-epithelia. These data constitute strong evidence that a dysregulation of COX-1-coupled prostaglandin contributes to diabetes-impaired wound healing.

Animals↗
PubMed2004

Induction of apoptosis in human prostate stromal cells by 4-hydroxytamoxifen: an alternative therapy for benign prostate hyperplasia.

Benign prostate hyperplasia (BPH) is a disease of the aging male. In BPH, the imbalance of cell proliferation and programmed cell death (apoptosis) leads to continuous stromal growth. Common medication interrupts stromal cell proliferation but has only little effect on inducing stromal cell apoptosis. In this study, we investigated tamoxifen (TAM) and 4-hydroxytamoxifen (OHT) for their ability to induce apoptosis in human prostate stromal cells (PrSC) in vitro. After the incubation of PrSC with different concentrations of TAM or OHT, the cytotoxic effect was measured using an MTT-assay. The induction of apoptosis after OHT treatment was investigated by FACS-analysis (annexin V FITC staining) and Western blot (PARP-1 cleavage, BCL-2 and BAX-alpha expression). The administration of TAM at concentrations of 0-20 microM had very little effect on cell viability as measured by MTT assay. In contrast, the use of 10-20 microM OHT led to a significant decrease in cell viability. The binding of annexin V FITC to apoptotic cells was demonstrated by FACS-analysis. The induction of apoptosis was further proven by Western blot of PARP-1 protein cleavage and the expression of the anti-apoptotic BCL-2 and the pro-apoptotic BAX-alpha proteins. In conclusion, our data clearly demonstrate, that the administration of OHT at concentrations from 10-20 microM induced apoptosis in human PrSC. The more effective induction of apoptosis with OHT compared with TAM could very well explain the results of clinical studies showing no clinical effect of TAM treatment on BPH. Furthermore, our results, if reproducible in vivo, could open new avenues for the treatment of BPH by local administration of OHT in apoptosis-inducing concentrations.

Apoptosis↗