Aspirin and other anti-inflammatory drugs

Health Benefits of Anti-aging Drugs

Aging, as a physiological process mediated by numerous regulatory pathways and transcription factors, is manifested by continuous progressive functional decline and increasing risk of chronic diseases. There is an increasing interest to identify pharmacological agents for treatment and prevention of age-related disease in humans. Animal models play an important role in identification and testing of anti-aging compounds; this step is crucial before the drug will enter human clinical trial or will be introduced to human medicine. One of the main goals of animal studies is better understanding of mechanistic targets, therapeutic implications and side-effects of the drug, which may be later translated into humans. In this chapter, we summarized the effects of different drugs reported to extend the lifespan in model organisms from round worms to rodents. Resveratrol, rapamycin, metformin and aspirin, showing effectiveness in model organism life- and healthspan extension mainly target the master regulators of aging such as mTOR, FOXO and PGC1α, affecting autophagy, inflammation and oxidative stress. In humans, these drugs were demonstrated to reduce inflammation, prevent CVD, and slow down the functional decline in certain organs. Additionally, potential anti-aging pharmacologic agents inhibit cancerogenesis, interfering with certain aspects of cell metabolism, proliferation, angioneogenesis and apoptosis.

Highly unsaturated fatty acids (HUFA) mediate and monitor food's impact on health

A hyperbolic, saturable, competitive dynamic of ligand binding to metabolic enzymes and lipid mediator receptors gives non-linear dose-response interactions that need careful management when planning or interpreting nutrient-based interventions. Relatively indiscriminate metabolism during accumulation of HUFA from n-3 and n-6 nutrients allows the amounts of n-3 and n-6 nutrients to determine the HUFA balance accumulated in tissue phospholipids. However, when HUFA-based eicosanoid actions are more intense with n-6 than n-3 mediators, they cause healthy physiology to shift toward pathophysiology. The proportion of n-6 in tissue HUFA directly relates to the severity of conditions caused by excessive n-6 actions. In the absence of n-3 nutrients, dietary linoleate (18:2n-6) has a very narrow therapeutic window below 1 percent of food energy, and it is widened by n-3 nutrients. The predictable quantitative dynamics of competing n-3 and n-6 nutrients allows design of successful preventive nutrition protocols that confirm and extend the epidemiologically observed benefits of n-3 nutrients.

Finding Ponce de Leon's Pill: Challenges in Screening for Anti-Aging Molecules

Aging is characterized by the progressive accumulation of degenerative changes, culminating in impaired function and increased probability of death. It is the major risk factor for many human pathologies - including cancer, type 2 diabetes, and cardiovascular and neurodegenerative diseases - and consequently exerts an enormous social and economic toll. The major goal of aging research is to develop interventions that can delay the onset of multiple age-related diseases and prolong healthy lifespan (healthspan). The observation that enhanced longevity and health can be achieved in model organisms by dietary restriction or simple genetic manipulations has prompted the hunt for chemical compounds that can increase lifespan. Most of the pathways that modulate the rate of aging in mammals have homologs in yeast, flies, and worms, suggesting that initial screening to identify such pharmacological interventions may be possible using invertebrate models. In recent years, several compounds have been identified that can extend lifespan in invertebrates, and even in rodents. Here, we summarize the strategies employed, and the progress made, in identifying compounds capable of extending lifespan in organisms ranging from invertebrates to mice and discuss the formidable challenges in translating this work to human therapies.

Effects of triptolide on hippocampal microglial cells and astrocytes in the APP/PS1 double transgenic mouse model of Alzheimer's disease

The principal pathology of Alzheimer's disease includes neuronal extracellular deposition of amyloid-beta peptides and formation of senile plaques, which in turn induce neuroinflammation in the brain. Triptolide, a natural extract from the vine-like herb Tripterygium wilfordii Hook F, has potent anti-inflammatory and immunosuppressive efficacy. Therefore, we determined if triptolide can inhibit activation and proliferation of microglial cells and astrocytes in the APP/PS1 double transgenic mouse model of Alzheimer's disease. We used 1 or 5 μg/kg/d triptolide to treat APP/PS1 double transgenic mice (aged 4-4.5 months) for 45 days. Unbiased stereology analysis found that triptolide dose-dependently reduced the total number of microglial cells, and transformed microglial cells into the resting state. Further, triptolide (5 μg/kg/d) also reduced the total number of hippocampal astrocytes. Our in vivo test results indicate that triptolide suppresses activation and proliferation of microglial cells and astrocytes in the hippocampus of APP/PS1 double transgenic mice with Alzheimer's disease.

Antipyretic analgesic drugs have different mechanisms for regulation of the expression of inducible nitric oxide synthase in hepatocytes and macrophages

Antipyretic analgesic drugs (including non-steroidal anti-inflammatory drugs) inhibit cyclooxygenase-2 and inducible nitric oxide synthase (iNOS), resulting in decreases of the proinflammatory mediators prostaglandin E2 and nitric oxide (NO), respectively. Both mediators are regulated by nuclear factor-kappa B (NF-κB), a key transcription factor in inflammation. Few reports have compared the efficacy and potency of anti-inflammatory drugs as NO inhibitors. In our study, we examined the effects of four popular antipyretic analgesic drugs on NO production induced in hepatocytes and macrophages. Mouse RAW264.7 macrophages treated with bacterial lipopolysaccharide showed the highest efficacy with regard to NO production; aspirin, loxoprofen, ibuprofen, and acetaminophen dose-dependently suppressed NO induction. Ibuprofen showed the highest potency in suppressing the induced production of NO. In rat hepatocytes, all the drugs inhibited interleukin 1β-induced NO production and ibuprofen and loxoprofen inhibited NO induction effectively. Unexpectedly, the potency of NO suppression of each drug in hepatocytes did not always correlate with that observed in RAW264.7 cells. Microarray analyses of mRNA expression in hepatocytes revealed that the effects of the four antipyretic analgesic drugs modulated the NF-κB signaling pathway in a similar manner to the regulation of the expression of genes associated with inflammation, including the iNOS gene. However, the affected signal-transducing molecules in the NF-κB pathway were different for each drug. Therefore, antipyretic analgesic drugs may decrease NO production by modulating the NF-κB pathway in different ways, which could confer different efficacies and potencies with regard to their anti-inflammatory effects.

Topical nasal lysine aspirin in aspirin-sensitive and aspirin-tolerant chronic rhinosinusitis with nasal polyposis

Chronic rhinosinusitis patients with nasal polyps can be aspirin sensitive or aspirin tolerant. The majority belong to the latter group. They tolerate intake of aspirin or other non-steroidal anti-inflammatory drugs, whereas aspirin-sensitive patients have an adverse reaction (asthma, rhinitis and/or urticaria). Diagnosis of aspirin sensitivity is important for the patient, but is rarely undertaken in routine ENT or respiratory medicine practice. Treatment of nasal polyps is by a combination of medical therapy and surgery. Oral and topical steroids form the mainstay of medical therapy, which is aimed at reducing inflammation and symptom improvement. Surgery helps with polyps causing severe nasal obstruction. Despite these therapies, recurrences are common in aspirin sensitive patients. Any adjunctive therapy to prevent or prolong recurrence would be welcome. One such possibility is topical nasal lysine-aspirin. This is an area under current debate and this non-systematic review aims to provide evidence of its use, to date, in aspirin sensitive and aspirin tolerant nasal polyp patients.

Comparison of the anti-inflammatory and analgesic effects in rats of diclofenac-sodium, felbinac and indomethacin patches

BACKGROUND

Topically applied nonsteroidal anti-inflammatory drugs (NSAIDs) are used widely for the treatment of pain and inflammation in musculoskeletal disorders. This study compared the analgesic and anti-inflammatory effects of patches of 1% diclofenac-sodium, 3.5% and 0.5% felbinac and 3.75% indomethacin in rats using the carrageenan-induced paw pad edema model and the brewer's yeast-induced hyper algesia model. Two studies were conducted: in the preliminary study, the patch was removed at 2 or 24 hrs after application, and in the main study the patch was removed at 2 hrs. The volume of the right hind paw and the pain threshold were assessed at 1, 3, 5, and 7 hrs after induction of inflammation in both studies.

RESULTS

In the main study, the edema ratio in the 1% diclofenac group at 5 hrs after induction of inflammation and the AUEC (Area Under the Effect Curve) were significantly lower than in the control animals (p=0.009). The edema suppression rate in the 1% diclofenac group (12.1-33.2%) was higher than in the 3.5% and 0.5% felbinac and 3.75% indomethacin groups. The pain threshold ratio did not decrease in the 1% diclofenac group and it was significantly higher than in the control group at 3 (p=0.0004) and 5 hrs (p=0.029). The 1/AUEC was significantly lower than that in the control group (p=0.004) and the lowest among all the NSAID groups.

CONCLUSIONS

This study demonstrated that the analgesic and anti-inflammatory effects of the 1% diclofenac sodium patch in a rat model may be exerted more promptly and persistently than with the 3.5% and 0.5% felbinac and 3.75% indomethacin patches.

Laboratory evaluation of aspirin responsiveness

Aspirin is the most commonly used antiplatelet medication. Laboratory monitoring of aspirin response has recently become a topic of interest due to potential impacts on patient management and clinical outcomes. This article summarizes available laboratory testing of aspirin response with focus on technical issues, limitations, and current opinion on the utility of routine patient testing.

Safety of Selective COX‐2 Inhibitors in Aspirin/Nonsteroidal Anti‐inflammatory Drug‐Intolerant Patients: Comparison of Nimesulide, Meloxicam, and Rofecoxib

BACKGROUND

Intolerance to acetylsalicylic acid (ASA) and other nonsteroidal anti-inflammatory drugs (NSAIDs) is a crucial problem in clinical practice. There is, therefore, a need for safer NSAIDs in patients with analgesic intolerance.

OBJECTIVE

To assess the safety of nimesulide, meloxicam, and rofecoxib, selective COX-2 inhibitors, in a group of ASA/NSAIDs-intolerant patients.

METHOD

Tolerances to nimesulide, meloxicam, and rofecoxib were assessed by single-blind placebo-controlled oral challenges. One hundred twenty-seven subjects with history of adverse reaction to ASA/NSAIDs received oral challenges with nimesulide, 61 subjects were challenged with meloxicam, 51 subjects were challenged with rofecoxib, and 37 subjects were challenged with all three drugs. Placebos were given to all patients on the first day of the study. On the second day, one-fourth and three-fourths of the therapeutic doses of the active drugs (nimesulide 100 mg, meloxicam 7.5 mg, or rofecoxib 25 mg) were given at 60-minute intervals. There was at least a 3-day interval between challenge tests. Erythema, pruritus accompanied by erythema, urticaria/angioedema, rhinorrhea, nasal obstruction, sneezing, dyspnea, or cough associated with a decrease of at least 20% in the forced expiratory volume (FEV1) and hypotension were considered as positive reactions.

RESULTS

Positive reactions to the nimesulide, meloxicam, and rofecoxib challenges were observed in 18/127 (14.3%), 5/61 (8.1%), and 1/51 (2.0%) patients, respectively. In each group of nine patients, there were two patients with asthma and four who developed skin type reactions and asthmatic reactions, respectively, to the nimesulide challenge. Among five patients who reacted to the meloxicam challenge, asthmatic type reactions were detected in two asthmatics. Only one urticarial type reaction was observed with rofecoxib challenge in one patient who presented with anaphylaxis to ASA/NSAIDs. All patients with asthma tolerated rofecoxib without any adverse effects. None of the patients reacted to the placebo. Among 37 patients challenged with all three drugs, 11 reacted to nimesulide, and one patient reacted only to meloxicam. Three patients reacted to more than one of the drugs tested, and one of them reacted to all drugs.

CONCLUSION

This is the first placebo-controlled report comparing these three drugs. The results indicate that among these alternative drugs for ASA/NSAIDs-intolerant patients, rofecoxib seems to have the most favorable tolerability.

Lack of effect of naltrexone on the spinal synergism between morphine and non steroidal anti-inflammatory drugs

To enhance analgesia, the combinatorial use of analgesic drugs with proven efficacies is a widely-used strategy to reduce adverse side effects. The present study characterizes the antinociceptive interaction of intrathecal morphine co-administered with different NSAIDs using isobolographic analysis.Antinoceptive activity was evaluated using a model for acute visceral pain, the writhing test of mice. The possible involvement of opioid receptors in the mechanism of action of the intrathecal co-administration of morphine and NSAIDs was investigated using the non-selective receptor antagonist naltrexone. The study demonstrated a synergistic antinociception of intrathecal administered combinations of morphine with the following NSAIDs: diclofenac, ketoprofen, meloxicam, metamizol, naproxen, nimesulide, parecoxib and piroxicam. The supra additive effect was obtained with very low doses of each drug and it appeared to be independent of the COX-1 or COX-2 inhibition selectivity of each NSAID and was not significantly modified by intrathecal naltrexone. The findings of the present work suggest that the combination of opioids and NSAIDs has a direct action on spinal nociceptive processing, which may be achieved via mechanisms that are independent of the activation of opioid receptors. The ineffectiveness of naltrexone to reverse the analgesic activity of opioids + NSAIDs combinations indicates that other complex pain regulatory systems are involved in this effect.

Competitive inhibition of organic anion transporting polypeptide 1c1-mediated thyroxine transport by the fenamate class of nonsteroidal antiinflammatory drugs

Organic anion transporting polypeptide (Oatp) 1c1 is a high-affinity T(4) transporter with narrow substrate specificity expressed at the blood-brain barrier. A transport model using cells overexpressing Oatp1c1 was created to identify novel Oatp1c1 substrates and inhibitors. Rat Oatp1c1 was cloned and stably expressed in human embryonic kidney 293 cells. Oatp1c1-transfected human embryonic kidney 293 cells transported (125)I-labeled T(4) in a time-dependent manner that was completely abolished in the presence of excess unlabeled T(4). Next, various compounds, including inhibitors of thyroid hormone uptake, were screened for inhibitory effects on Oatp1c1-mediated T(4) uptake. Phenytoin (64%), indocyanine green (17%), fenamic acid (68%), diclofenac (51%), and meclofenamic acid (33%) all reduced T(4) uptake by Oatp1c1 when assayed at concentrations of 10 microM. Dose-response assays for the fenamic acids, iopanoic acid, indocyanine green, and phenytoin revealed IC(50) values for Oatp1c1 T(4) uptake below or near the blood plasma levels after therapeutic doses. Further kinetic assays and reciprocal plot analyses demonstrated that the fenamic acid diclofenac inhibited in a competitive manner. Finally, microvessels were isolated from adult rat brain and assessed for T(4) uptake. Ten micromolar of fenamate concentrations inhibited T(4) microvessel uptake with a similar hierarchical inhibition profile [fenamic acid (43%), diclofenac (78%), and meclofenamic acid (85%)], as observed for Oatp1c1 transfected cells. Oatp1c1 is expressed luminally and abluminally in the blood-brain barrier endothelial cell, and exhibits bidirectional transport capabilities. Together, these data suggest that Oatp1c1 transports fenamates into, and perhaps across, brain barrier cells.

Design of aging intervention studies: the NIA interventions testing program

The field of biogerontology has made great strides towards understanding the biological processes underlying aging, and the time is ripe to look towards applying this knowledge to the pursuit of aging interventions. Identification of safe, inexpensive, and non-invasive interventions that slow the aging process and promote healthy aging could have a significant impact on quality of life and health care expenditures for the aged. While there is a plethora of supplements and interventions on the market that purport to slow aging, the evidence to validate such claims is generally lacking. Here we describe the development of an aging interventions testing program funded by the National Institute on Aging (NIA) to test candidate interventions in a model system. The development of this program highlights the challenges of long-term intervention studies and provides approaches to cope with the stringent requirements of a multi-site testing program.

Nordihydroguaiaretic acid and aspirin increase lifespan of genetically heterogeneous male mice

The National Institute on Aging's Interventions Testing Program was established to evaluate agents that are purported to increase lifespan and delay the appearance of age-related disease in genetically heterogeneous mice. Up to five compounds are added to the study each year and each compound is tested at three test sites (The Jackson Laboratory, University of Michigan, and University of Texas Health Science Center at San Antonio). Mice in the first cohort were exposed to one of four agents: aspirin, nitroflurbiprofen, 4-OH-alpha-phenyl-N-tert-butyl nitrone, or nordihydroguaiaretic acid (NDGA). Sample size was sufficient to detect a 10% difference in lifespan in either sex,with 80% power, using data from two of the three sites. Pooling data from all three sites, a log-rank test showed that both NDGA (p=0.0006) and aspirin (p=0.01) led to increased lifespan of male mice. Comparison of the proportion of live mice at the age of 90% mortality was used as a surrogate for measurement of maximum lifespan;neither NDGA (p=0.12) nor aspirin (p=0.16) had a significant effect in this test. Measures of blood levels of NDGA or aspirin and its salicylic acid metabolite suggest that the observed lack of effects of NDGA or aspirin on life span in females could be related to gender differences in drug disposition or metabolism. Further studies are warranted to find whether NDGA or aspirin, over a range of doses,might prove to postpone death and various age-related outcomes reproducibly in mice.

Aspirin-exacerbated asthma

: This review focuses on aspirin-exacerbated asthma (AEA). The review includes historical perspective of aspirin, prevalence, pathogenesis, clinical features and treatment of AEA. The pathogenesis of AEA involves the cyclooxygenase and lipooxygenase pathway. Aspirin affects both of these pathways by inhibiting the enzyme cycooxygenase-1 (COX-1). Inhibition of COX-1 leads to a decrease in prostaglandin E2 (PGE2). The decrease in PGE2 results in an increase in cysteinyl leukotrienes by the lipooxygenase pathway involving the enzyme 5-lipooxygenase (5-LO). Leukotriene C4 (LTC4) synthase is the enzyme responsible for the production of leukotriene C4, the chief cysteinyl leukotriene responsible for AEA. There have been familial occurences of AEA. An allele of the LTC4 synthase gene in AEA is known as allele C. Allele C has a higher frequency in AEA. Clinical presentation includes a history of asthma after ingestion of aspirin, nasal congestion, watery rhinorrhea and nasal polyposis. Treatment includes leukotriene receptor antagonists, leukotriene inhibitors, aspirin desinsitaztion and surgery. AEA is the most well-defined phenotype of asthma. Although AEA affects adults and children with physician-diagnosed asthma, in some cases there is no history of asthma and AEA often goes unrecognized and underdiagnosed.

ATL-1, an analogue of aspirin-triggered lipoxin A4, is a potent inhibitor of several steps in angiogenesis induced by vascular endothelial growth factor

BACKGROUND AND PURPOSE

Vascular endothelial growth factor (VEGF) is the most important proangiogenic protein. We have demonstrated that ATL-1, a synthetic analogue of aspirin-triggered lipoxin A(4), inhibits VEGF-induced endothelial cell (EC) migration. In the present study, we investigated the effects of ATL-1 in several other actions stimulated by VEGF.

METHODS

Human umbilical vein ECs were treated with ATL-1 for 30 min before stimulation with VEGF. Cell proliferation was measured by thymidine incorporation. Adherent cells were determined by fluorescence intensity using a Multilabel counter. Expression and activity of matrix metalloproteinases (MMP) were analysed by western blot and zymography.

KEY RESULTS

ATL-1 inhibited EC adhesion to fibronectin via interaction with its specific receptor. Furthermore, VEGF-induced MMP-9 activity and expression were reduced by pretreatment with ATL-1. Because the transcription factor NF-kappaB has been implicated in VEGF-mediated MMP expression and EC proliferation, we postulated that ATL-1 might modulate the NF-kappaB pathway and, indeed, ATL-1 inhibited NF-kappaB nuclear translocation. Pretreatment of EC with ATL-1 strongly decreased VEGF-dependent phosphorylation of phosphainositide 3-kinase (PI3-K) and extracellular signal-regulated kinase-2 (ERK-2), two signalling kinases involved in EC proliferation. Inhibition of VEGF-induced EC proliferation by ATL-1 was antagonized by sodium orthovanadate, suggesting that this inhibitory activity was mediated by a protein tyrosine phosphatase. This was confirmed by showing that ATL-1 inhibition of VEGF receptor-2 (VEGFR-2) phosphorylation correlates with SHP-1 association with VEGFR-2.

CONCLUSIONS AND IMPLICATIONS

The synthetic 15-epi-lipoxin analogue, ATL-1, is a highly potent molecule exerting its effects on multiple steps of the VEGF-induced angiogenesis.

Persistence of NSAIDs at effect sites and rapid disappearance from side-effect compartments contributes to tolerability

BACKGROUND

Non-steroidal, anti-inflammatory drugs (NSAIDs) are still the most widely used drugs worldwide. The introduction of selective cyclooxygenase (COX)-2 inhibitors has led to compounds which appear less damaging to the gastrointestinal tract, but possibly more risky to the cardiovascular system than older drugs. None has as yet reached OTC-status.

OBJECTIVE

This situation necessitates an analysis of the characteristics of those older ones which - due to their relative safety - have achieved over-the-counter (OTC) status.

DESIGN

The pharmacodynamic and pharmacokinetic characteristics of non-selective COX inhibitors in OTC use were obtained from the literature by systematic search, examined and used to construct a coherent hypothesis why they achieved OTC status, i.e. effectiveness and relative safety at low doses.

RESULTS

Pharmacodynamic (COX-2 preferential, but not selective inhibition) and, more importantly, pharmacokinetic characteristics of some of the older compounds may make them particularly safe drugs if used at low (OTC) doses with treatment limited to a few days of intake. The reason why some NSAIDs are particularly active while being relatively free from side-effects may be due to their specific biodistribution and metabolism, leading to drug accumulation and persistence in inflamed tissue (effect compartment) together with fast clearance from the central compartment, including blood, vascular wall, heart and kidney, i.e., possible sideeffect compartments.

CONCLUSION

This specific pharmacokinetic behavior of some non-selective COX inhibitors, such as diclofenac and ibuprofen, may explain why these widely used, non-steroidal, anti-inflammatory compounds are relatively well suited for OTC use and why some are more appropriate for the therapy of certain pain conditions than others.

An Aging Interventions Testing Program: study design and interim report

The National Institute on Aging's Interventions Testing Program (ITP) has developed a plan to evaluate agents that are considered plausible candidates for delaying rates of aging. Key features include: (i) use of genetically heterogeneous mice (a standardized four-way cross), (ii) replication at three test sites (the Jackson Laboratory, TJL; University of Michigan, UM; and University of Texas, UT), (iii) sufficient statistical power to detect 10% changes in lifespan, (iv) tests for age-dependent changes in T cell subsets and physical activity, and (v) an annual solicitation for collaborators who wish to suggest new interventions for evaluation. Mice in the first cohort were exposed to one of four agents: aspirin, nitroflurbiprofen (NFP), 4-OH-alpha-phenyl-N-tert-butyl nitrone (4-OH-PBN), or nordihydroguiaretic acid (NDGA). An interim analysis was conducted using survival data available on the date at which at least 50% of the male control mice had died at each test site. Survival of control males was significantly higher, at the interim time-point, at UM than at UT or TJL; all three sites had similar survival of control females. Males in the NDGA group had significantly improved survival (P = 0.0004), with significant effects noted at TJL (P < 0.01) and UT (P < 0.04). None of the other agents altered survival, although there was a suggestion (P = 0.07) of a beneficial effect of aspirin in males. More data will be needed to determine if any of these compounds can extend maximal lifespan, but the current data show that NDGA reduces early life mortality risks in genetically heterogeneous mice at multiple test sites.

Resistance exercise and cyclooxygenase (COX) expression in human skeletal muscle: implications for COX-inhibiting drugs and protein synthesis

We have shown that ibuprofen and acetaminophen block cyclooxygenase (COX) synthesis of prostaglandin PGF2αand the muscle protein synthesis increase following resistance exercise. Confusingly, these two drugs are purported to work through different mechanisms, with acetaminophen apparently unable to block COX and ibuprofen able to nonspecifically block COX-1 and COX-2. A recently discovered intron-retaining COX, now known to have three variants, has been shown to be sensitive to both drugs. We measured the expression patterns and levels of the intron 1-retaining COX-1 variants (-1b1, -1b2, and -1b3), COX-1, and COX-2 at rest and following resistance exercise to help elucidate the COX through which PGF2α, ibuprofen, and acetaminophen regulate muscle protein synthesis. Skeletal muscle biopsy samples were taken from 16 individuals (8M, 8F) before, 4, and 24 h after a bout of resistance exercise and analyzed using real-time RT-PCR. Relatively few individuals expressed the intron 1-retaining COX-1b variants (COX-1b1, -1b2, and -1b3) at any time point, and when expressed, these variants were in very low abundance. COX-1 was the most abundant COX mRNA before exercise and remained unchanged ( P > 0.05) following exercise. COX-2 was not expressed before exercise, but increased significantly ( P < 0.05) at 4 and 24 h after exercise. The inconsistent and low levels of expression of the intron 1-retaining COX-1 variants suggest that these variants are not likely responsible for the inhibition of PGF2αproduction and skeletal muscle protein synthesis after resistance exercise by ibuprofen and acetaminophen. Skeletal muscle-specific inhibition of COX-1 or COX-2 by these drugs should be considered.

Immunohistochemical demonstration of cyclooxygenase-2 (COX-2) and prostaglandin receptors EP2 and FP expression in the bovine intercaruncular uterine wall around term

During parturition, uterine-derived prostaglandins (PG) play an outstanding role regarding the functional elimination of the corpus luteum and the promotion of uterine contraction. The rate-limiting enzyme cyclooxygenase-2 (COX-2), highly regulated in a cell-type and localization specific manner throughout pregnancy, is involved in uterine prostanoid production. Prostaglandins exert their effects via G-protein-coupled receptors. Distribution and cellular localization of these receptors are decisive factors for prostaglandin-mediated actions. Since both COX-2 and PG receptors have only been assessed during pregnancy in the cow, these parameters were localized immunohistochemically near term to evaluate their specific role at parturition. Thus, during two periods, segments of the intercaruncular uterine wall were collected from cows at slaughter being eight and nine months pregnant, from cattle during caesarean section, and after spontaneous calving. Results reveal that COX-2 was mainly localized in the cytoplasm of surface epithelial cells with a high expression in animals with induced parturition. The enzyme could also be found in lower concentrations within the glandular epithelium without any effect of gestational time or labour. In contrast to relaxant prostaglandin E receptor type 2 (EP2), not showing any change in all tissue layers observed, contractile prostaglandin F(2alpha) receptor (FP) was modulated during the peripartal period revealing a peak expression in animals with induced parturition. FP was localized in surface and glandular epithelial cells as well as in endometrial stroma and myometrial smooth muscle cells. Our study indicates that labour and induction of parturition may have an effect on amounts of immunohistochemically detectable COX-2 and FP. EP2 remains rather unchanged during the peripartal period. COX-2 and FP thus contribute via changes in amount and distribution to mechanisms associated with parturition.

Interaction between cyclooxygenase (COX)-1- and COX-2-products modulates COX-2 expression in the late phase of acute inflammation

Prostanoid production depends on the activity of two cyclooxygenase (COX) isoforms. It is appreciated that COX-1 plays a role in physiological processes, whereas COX-2 acts in pathological conditions. However their roles, particularly roles of COX-1, have not yet been fully established in inflammation. Here, we examined the effects of COX inhibitors, having differential isoform selectivity, on the late phase of rat carrageenin-induced pleurisy to elucidate the role of COX-2 expressed in the draining lymph nodes and found substantial contribution of COX-1-product(s). Protein and mRNA of COX-2 were detectable with Western blotting analysis and reverse-transcription polymerase chain reaction (RT-PCR) analysis in parathymic lymph nodes, peaking at 48 h after induction of pleurisy. Microsomal prostaglandin E synthase (mPGES)-1 was detectable by immunohistochemical analysis in cells with dendritic processes, a morphological characteristic similar to that of COX-2 expressing cells. Although aspirin, indomethacin and a COX-1 inhibitor, ketorolac, significantly decreased the volume of pleural exudate, they did not affect the levels of COX-2 and mPGES-1 in the lymph node 24 h after induction of pleurisy. In contrast, COX-2 inhibitors, nimesulide and NS-398, had no effect on the exudate volume, but they increased the number of COX-2- and mPGES-1-expressing cells and extension of their dendritic processes with significant increase in the COX-2 level, which were antagonised by ketorolac. These results suggest that COX-2-expressing cells may negatively self-regulate their functions by producing PGE2 via mPGES-1: migration into the draining lymph node and their differentiation. Moreover, COX-1- and COX-2-derived prostanoids may play differential or sometimes antagonistic roles in the late phase of acute inflammation.

Complexity of Anti-immunosenescence Strategies in Humans

Immunosenescence is characterized by three main aspects: (i) the shrinkage of the T cell repertoire and the accumulation of oligoclonal expansions (megaclones) of memory/effector cells directed toward ubiquitary infectious agents; (ii) the involution of the thymus and the exhaustion of naïve T cells; and (iii) a chronic inflammatory status called inflamm-aging. We present here possible strategies to counteract these main aspects of immunosenescence in humans with particular attention to the reduction of antigenic load by pathogens, such as CMV, and the normalization of intestinal microflora, the possible utilization of IL-7 to reverse thymic involution, the purging of megaclones, the forced expression of CD28 on T lymphocytes, the reduction of inflamm-aging and the administration of nutrients such as vitamin D. Possible drawbacks of all these strategies are discussed. Finally, the complexity of a rejuvenation approach is stressed, with particular attention to the inhibitory role played by the "old microenvironment" on the performance of progenitor cells, the best candidate to counteract the decline in regenerative potential characteristic of organs and tissues from old organisms.

Effects of age and resistance exercise on skeletal muscle interstitial prostaglandin F(2alpha)

Prostaglandin (PG) F2alpha has been shown to contribute to the anabolic events in skeletal muscle. We measured the skeletal muscle interstitial concentration of PGF2alpha at rest and following a standard bout of resistance exercise in eight young (27+/-2 year) and eight old (75+/-4 year) men. Interstitial PGF2alpha concentration was determined from microdialysate samples obtained from two microdialysis probes placed in the vastus lateralis. Microdialysates were collected 1h pre- and 5-6, 8-9, and 24-25 h postexercise. The exercise bout consisted of 4 exercises (3 sets of 8 replications at 80% 1 RM per exercise) emphasizing the quadriceps. Interstitial PGF2alpha levels were not different (P>0.05) between young and old at rest (1.50+/-0.35 vs. 1.52+/-0.30 ng ml-1) or at any time point following the resistance exercise bout. For the young and old combined there was a change (P<0.05) in PGF2alpha levels at 5-6 h (93%) and 8-9 h (95%), which had returned to preexercise levels by 24-25 h. These results show that PGF2alpha is increased in skeletal muscle following a standard bout of resistance exercise and aging does not alter interstitial levels of this PG at rest or after exercise. These data, coupled with previous findings, suggest that the anabolic factor PGF2alpha should be considered when discussing the complex processes that regulate muscle mass in young and old individuals.

Angiogenesis and lipoxins

Angiogenesis, the growth of new capillaries from pre-existing ones, occurs through dynamic functions of the endothelial cells (EC), including migration, proliferation and maturation, which are essential to achieve an organized formation of the vessel sprout. Aspirin-triggered lipoxins (ATL), the 15R enantiomeric counterparts of native lipoxins, are endogenous lipid mediators generated within the vascular lumen during multicellular responses, which display potent and well-described immunomodulatory actions. Here we present some of the findings regarding the inhibition of EC responses in vitro and in vivo by these novel compounds and the modulation of fundamental steps of the angiogenic process, identifying previously unappreciated vascular actions of locally generated ATL and their longer acting synthetic analogs.

Aspirin-triggered Lipoxin A4 inhibition of VEGF-induced endothelial cell migration involves actin polymerization and focal adhesion assembly

Angiogenesis, the growth of new capillaries from pre-existing ones, occurs through dynamic functions of the endothelial cells (EC), including migration, which is essential to achieve an organized formation of the vessel sprout. We demonstrated previously that an aspirin-triggered lipoxin analog, 15-epi-16-(para-fluoro)-phenoxy-lipoxin A4 (ATL-1), inhibits vascular endothelial growth factor (VEGF)-induced EC migration. In the present study, we investigated the effects of ATL-1 in the actin cytoskeleton reorganization of EC stimulated with VEGF. Pretreatment of EC with ATL-1 caused a reduction in VEGF-induced stress fibers and therefore reduced the intracellular content of filamentous actin. A concomitant impairment in stress-activated protein kinase (SAPK2/p38) phosphorylation suggests that ATL inhibition of VEGF-stimulated actin polymerization involves the SAPK2/p38 pathway. Moreover, ATL-1 treatment inhibited focal adhesion clustering due to inhibition of focal adhesion kinase (FAK) phosphorylation and the subsequent association of FAK with the actin cytoskeleton. This final event, which ultimately allows cell migration, was reverted by an LX receptor antagonist, but not by a cys-LT1R antagonist, indicating an effect via the G-protein-linked LXA4 receptor. Together our results provide evidence that ATL-1 inhibits EC migration via the concerted inhibition of actin polymerization and proper assembly of focal adhesions, supporting a role for these novel lipid mediators as angiogenesis modulators.

Protective Effects of Angiotensin II Interruption: Evidence for Antiinflammatory Actions

Angiotensin II, the major effector molecule produced from the renin-angiotensin-aldosterone axis, is a vasoconstrictor contributing to hypertension. Evidence indicates, however, that angiotensin II also is a potent proinflammatory mediator with growth and remodeling effects. In vitro and in vivo studies have shown that angiotensin II blockade significantly reduces concentrations of proinflammatory mediators and oxidative stress products in numerous inflammatory models. Interruption of angiotensin II activity with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers has been beneficial for patients with inflammatory diseases. Much of this benefit occurs independent of the antihypertensive effect of angiotensin II interruption, suggesting a distinctive protective mechanism. Angiotensin II receptor blockers may represent a novel class of antiinflammatory drugs with indications far beyond cardiovascular diseases.

Lifelong aspirin supplementation as a means to extending life span

Arising from an initiative by the National Institute of Aging (NIA) requesting novel proposals challenged with increasing lifespan and longevity, our laboratory has generated a hypothesis to test the efficacy of lifelong, low-dosage aspirin administration as a means to achieving this goal. The intervention testing program (currently underway) proposing aspirin as an anti-aging agent evolved from the multitude of properties encompassed in aspirin and the potential of these attributes to prevent the cellular and functional declines, particularly from inflammatory and oxidative sources, evidenced to contribute to aging. Aspirin is a widely administered, cheap, anti-inflammatory, and antioxidant compound that has a variety of positive effects on the immune system and cardiovascular health. Notably, aspirin may affect oxidant production, cytokine responses, and block glycooxidation reactions, thus posing it as a triple threat against the symptoms of aging. Whether aging is molded by interplay between oxidative stress and inflammatory mediators has received little attention; however, we and other laboratories have explored this notion and have observed an elevated inflammatory status with age. Stemming from these observations and in view of the limited success of antioxidant therapies in improving lifespan in long-lived species, in this article we propose a protocol to examine life-long use of a very low dose anti-inflammatory compound such as aspirin to engage the inflammatory and endogenous oxidative insults accompanying aging and, in so doing, attempt to increase maximum and mean life span.

Cyclooxygenase-2 and its role in ovulation: a 2004 account

The pre-ovulatory surge of gonadotrophins triggers a marked and obligatory increase in follicular prostaglandin synthesis prior to ovulation, and the cyclooxygenase (COX) enzyme is a key rate-limiting step in the biosynthesis of prostaglandins. In the early 1990s, the pre-ovulatory rise in follicular prostaglandin synthesis was shown to result from the selective induction of a novel COX isoform, now referred to as COX-2. Differences in the time-course of COX-2 induction in species with a short versus a long ovulatory process suggest that the enzyme could be a molecular determinant that sets the alarm of the mammalian ovulatory clock. Some of the fine molecular mechanisms involved in the transcriptional activation of the COX-2 gene in granulosa cells have also been elucidated. The binding of trans-activating upstream stimulatory factors (USF) to a consensus E-box cis-element in the proximal region of the promoter was shown to play a predominant role in COX-2 transcription. Studies showed that COX-2 expression could also serve as a valuable marker for follicular commitment to ovulation during hyperstimulatory cycles. This paper presents a comprehensive review of the events that led to the characterization of COX-2 in pre-ovulatory follicles, updates current concepts on the control of COX-2 expression in pre-ovulatory follicles, and addresses the consequences of COX-2 inhibition to women fertility and potential implications of COX-2 expression in ovarian cancer.

Synergy between the antinociceptive effects of morphine and NSAIDs

The intraperitoneal administration of morphine, diclofenac, ketoprofen, meloxicam, metamizol, paracetamol and piroxicam induced dose-dependent antinociception in mice tested with the acetic acid writhing test. The isobolographic analysis of the simultaneous intraperitoneal administration of fractions of the ED50's of morphine with each nonsteroidal anti-inflammatory drug (NSAID) demonstrated the existence of a supra-additive interaction (synergy). The selective antagonist of µ-opioid receptors naltrexone partially reversed the supra-additive interactions to additive interactions; however, the combinations of morphine/metamizol and morphine/paracetamol were completely antagonized, resulting in subadditive interactions. The selective antagonist of δ-opioid receptors naltrindole failed to significantly attenuate the combinations of morphine with ketoprofen, meloxicam and piroxicam, but decreased the activity of the combinations of morphine with diclofenac, metamizol and paracetamol, transforming the interactions from supra-additive to additive. Nor-binaltorphimine was used to evaluate the involvement of κ-opioid receptors. Nor-binaltor phimine did not modify the supra-additive interaction of morphine and NSAIDs and the additive interaction of the co-administration of morphine and metamizol. The synergy between morphine and NSAIDs could be related to different pathways of pain transmission, probably related to the different intracellular signal transduction mechanisms of action of opioid and non-opioid agents.Key words: writhing test, NSAIDs, morphine, antinociception, isobolographic analysis, synergy.

Prostaglandin E2 production in astrocytes: regulation by cytokines, extracellular ATP, and oxidative agents

Upregulation and activation of phospholipases A2 (PLA2) and cyclooxygenases (COX) leading to prostaglandin E2(PGE2) production have been implicated in a number of neurodegenerative diseases. In this study, we investigated PGE2 production in primary rat astrocytes in response to agents that activate PLA2 including pro-inflammatory cytokines (IL-1beta, TNFalpha and IFNgamma), the P2 nucleotide receptor agonist ATP, and oxidants (H2O2 and menadione). Exposure of astrocytes to cytokines resulted in a time-dependent increase in PGE2 production that was marked by increased expression of secretory sPLA2 and COX-2, but not COX-1 and cytosolic cPLA2. Although astrocytes responded to ATP or phorbol ester (PMA) with increased cPLA2 phosphorylation and arachidonic acid release, ATP or PMA only caused a small increase in levels of PGE2. However, when astrocytes were first treated with cytokines, further exposure to ATP or PMA, but not H2O2 or menadione, markedly increased PGE2 production. These results suggest that ATP release during neuronal excitation or injury can enhance the inflammatory effects of cytokines on PGE2 production and may contribute to chronic inflammation seen in Alzheimer's disease.

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Effect of the inhibition of serotonin biosynthesis on the antinociception induced by nonsteroidal anti-inflammatory drugs

The antinociceptive activity of nonsteroidal anti-inflammatory drugs (NSAIDs) has been explained mainly on the basis of their inhibition of the enzyme cyclooxygenase (COX); however, this inhibition is not enough to completely explain the analgesic efficacy of these drugs. The modulation exerted by serotonergic systems on antinociception is well known. The purpose of the present work was to further explore the role of serotonin in the antinociceptive activity of NSAIDs using the writhing test and the tail-flick test of the mice after the inhibition of serotonin biosynthesis with intraperitoneal p-chlorophenylalanine (p-CPA). Pretreatment with p-CPA produced a significant decrease in the antinociceptive activity of NSAIDs administered either by the intraperitoneal or intrathecal routes, in both algesiometric tests. These results suggest a complementary mechanism of antinociception for NSAIDs, independent of their ability to inhibit the activity of COX, involving the activation of descending serotonergic pathways. By the pharmacological nature of the study, one limitation was the absence of biochemical measurement of the synthesis of 5-HT, since the reduction of the brain 5-HT synthesis by pretreatment with p-CPA will be expressed as a diminished antinociceptive activity of NSAIDs, which would be a new argument to consider NSAIDs acting as central analgesic agents.

Cyclooxygenase (COX) inhibitors induce apoptosis in non-small cell lung cancer through cyclooxygenase independent pathways

Cyclooxygenase (COX) inhibitors are chemopreventive in many tumours but the role of COX inhibition in their effects is contentious. Here we determined if COX inhibitors influenced apoptosis in two non-small cell lung cancer cells one which over expresses COX-2 (MOR-P) and one which expresses neither isoform (H-460). NS398, a selective COX inhibitor, and indomethacin, a non-selective COX inhibitor, were cytotoxic in both cell lines, independently of their COX-2 expression. Furthermore, the cytotoxic concentrations were far greater than the concentrations required to inhibit COX. As indomethacin was more effective we used it in mechanistic studies. Indomethacin induced apoptotic cell death assessed as cytochrome c and apoptotic inducing factor (AIF) release, caspase activation, PARP, lamin B and gelsolin cleavage, chromatin condensation and nuclear fragmentation. The pan-caspase inhibitor, z-VAD, attenuated cell death, and blocked caspase activation, PARP cleavage and nuclear fragmentation without preventing cytochrome c release, suggesting that cytochrome c release is upstream of caspase activation. These observations suggest that COX inhibitors induce apoptosis in non-small lung cancer cells through cytochrome c and AIF release, and subsequent caspase activation, independently of COX-2 expression and prostaglandin production.

Atropine reverses the antinociception of nonsteroidal anti-inflammatory drugs in the tail-flick test of mice

The nonsteroidal anti-inflammatory drugs (NSAIDs) clonixin, diclofenac, piroxicam, ketoprofen, meloxicam, and paracetamol induced antinociception after intraperitoneal or intrathecal administration in mice submitted to an acute thermal algesiometric test without inflammation (tail-flick). Antinociception was evaluated by the increase in reaction time difference (Delta latency), between readings obtained before and after the administration of drugs. The antinociception induced by doses of NSAIDs producing between 20% and 30% of the maximum possible effect (MPE) 30 min after intraperitoneal and 15 min after intrathecal injections was compared with the antinociception obtained after pretreatment with 1 mg/kg atropine ip, 30 min before. Systemic atropine (1 mg/kg) significantly antagonized NSAID-induced antinociception in all cases, both after intraperitoneal and intrathecal administration. Cholinergic depletion by intracerebroventricular hemicholinium-3 (HC-3, 5 microg) 5 h before prevented the antinociceptive effect of all NSAIDs. These observations suggest that intrinsic muscarinic cholinergic facilitatory pathways represent an important modulating system in pain perception in this animal model of acute thermal pain. The results of the present work support the increasingly accepted notion that NSAIDs are effective analgesics even when inflammation is not present, acting by mechanisms that involve actions on spinal and supraspinal nociceptive transmission. It is suggested that, similar to morphine and clonidine, the active mechanism of NSAIDs may involve the release of acetylcholine (ACh) in the spinal cord.

Aspirin-intolerant asthma: role of cyclo-oxygenase enzymes

Aspirin-induced asthma and rhinitis (AIAR) appear to be precipitated by the inhibition of cyclo-oxygenase (COX). By inhibiting COX pathway aspirin diverts arachidonic acid metabolites to the lipoxygenase pathway. There are two isoforms of COX, namely COX-1 and COX-2. Metabolites derived from COX-1 are involved in cellular housekeeping functions. COX-2 can be induced in cells exposed to proinflammatory substances and growth factors. Recent studies have reported that patients with AIAR have decreased activity of COX-2 and lower production of PGE(2) in the upper airway and peripheral blood cells. Considering the protective effect of exogenous PGE(2) on aspirin-induced bronchoconstriction and the interdependence of PGE(2) and cisteinyl leukotriene production, a reduced PGE(2) synthesis may render aspirin-sensitive patients more susceptible to the inhibitory effect of NSAIDs drugs and also lead to an increase in cysteinyl leukotriene release.

NS-398: cyclooxygenase-2 independent inhibition of leukocyte priming for lipid body formation and enhanced leukotriene generation

Because the induction of new lipid body formation in leukocytes correlates with and likely contributes to their enhanced 'primed' prostaglandin and leukotriene formation, we evaluated two selective cyclooxygenase (COX)-2 inhibitors. Three types of stimuli, cis -unsaturated fatty acids, platelet activating factor and protein kinase C activators, stimulate lipid body formation. NS-398 (0.1-10 microM), but not another COX-2 inhibitor, SC58125 (0.1- 10 microM), blocked leukocyte lipid body formation elicited by all three types of stimuli and also blocked priming for enhanced LTB(4) production and PGE(2) production. The effect of NS-398 on lipid body formation was independent of its inhibitory effects on COX-2 since arachidonate-induced lipid body formation in COX-2-deficient mouse leukocytes was also inhibited by NS-398. By means of its ability to inhibit leukocyte lipid body formation, NS-398 may exert actions independent of its COX-2 inhibition and more broadly contribute to the suppression of formation of COX-1 and lipoxygenase-derived eicosanoids.

The use of analgesics in patients with asthma

Aspirin (acetylsalicylic acid) and other nonsteroidal anti-inflammatory drugs (NSAIDs) cause deterioration in respiratory function in approximately 10% of adults with asthma and a smaller proportion of children with asthma. We propose evidence-based guidelines for the safe use of NSAIDs in individuals with asthma following systematic review of data from the last 10 years relevant to the use of these drugs in such patients. We would currently recommend that patients with asthma who are known to be intolerant of NSAIDs or who exhibit any of the high risk clinical features for intolerance to these drugs (severe asthma, nasal polyps or chronic rhinosinusitis) should use NSAIDs only under close medical supervision. In those with high risk features formal aspirin provocation testing would be recommended prior to the therapeutic use of NSAIDs. Those individuals with asthma who regularly use NSAIDs can continue to do so but should be warned that intolerance to NSAIDs can develop late in life. Lack of relevant experimental evidence precludes the production of evidence-based guidelines for the group of patients with asthma who do not exhibit high risk clinical features and who have never before used NSAIDs. We would currently recommend that this group be treated as potentially intolerant to NSAIDs and use of these drugs can only be recommended under medical supervision but note that further studies and clinical experience could be expected to relax this restriction for many patients. Recent data have suggested that frequent use of paracetamol (acetaminophen) may contribute to a deterioration of respiratory function in asthma. A small proportion of patients with asthma who are NSAID-intolerant experience short-lived deterioration in respiratory function with the use of high doses of paracetamol but this is uncommon and has not been implicated in life-threatening reactions. Routine warnings about paracetamol use in asthma are, therefore, not warranted. Medical personnel, however, should be aware of the potential for worsening of symptoms in some individuals with asthma using paracetamol and institute formal investigation or withdrawal of the drug if they suspect such a reaction.

The mechanisms of aspirin-intolerant asthma and its management

Aspirin is one of the most widely used medications in the world. Adverse effects related to aspirin use were described almost concurrently with its first use. The most common side effects are gastrointestinal and renal, but adverse respiratory effects are not uncommon, and approximately 10% of adult asthmatics are aspirin intolerant. Many of these patients present with the so-called aspirin triad of aspirin sensitivity, chronic rhinosinusitis with associated nasal polyposis, and severe asthma. This paper provides a review of recent investigations into the pathogenesis of this process, which have furthered our understanding of the mechanisms and management of aspirin-induced asthma.

A new insight into aspirin-induced asthma

In about 10% of adult patients with asthma, aspirin and other nonsteroidal anti-inflammatory drugs precipitate attacks of dyspnoea. Accumulated evidence shows that these reactions are due to the interference of aspirin-like drugs with arachidonic acid metabolism in the lungs of the sensitive patients: inhibition of cyclooxygenase is accompanied by overproduction of cysteinyl leukotrienes. The mechanisms of these reactions and the characteristic course of aspirin-induced asthma and its management are discussed.

Novel lipid mediator regulators of endothelial cell proliferation and migration: aspirin-triggered-15R-lipoxin A(4) and lipoxin A(4)

Proliferative states such as chronic inflammation, ischemic diseases, and cancer are often accompanied by intense angiogenesis, a highly orchestrated process involving vessel sprouting, endothelial cell migration, proliferation, and maturation. Aspirin-triggered lipoxins (ATLs), the 15R enantiomeric counterparts of lipoxins (LXs), are endogenous mediators generated during multicellular responses that display potent immunomodulatory actions. Herein, we report a novel action for the ATL stable analog 15-epi-16-(para-fluoro)-phenoxy-lipoxin A(4) (denoted ATL-1), which proved to be a potent inhibitor of angiogenesis. This ATL inhibited endothelial cell proliferation in the 1 to 10 nM range by approximately 50% in cells stimulated with either vascular endothelial growth factor (VEGF) at 3 ng/ml or leukotriene D(4) at 10 nM. In addition, ATL-1 (in a 10-100 nM range) inhibited VEGF (3 ng/ml)-induced endothelial cell chemotaxis. In a granuloma in vivo model of inflammatory angiogenesis, ATL-1 treatment (10 microg/mouse) reduced by approximately 50% the angiogenic phenotype, as assessed by both vascular casting and fluorescence. Together, these results identify a novel and potent previously unappreciated action of aspirin-triggered 15-epi-LX.