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Thrombosis Research 110 (2003) 255 – 258
The William Harvey Research Institute, St. Bartholomew’s and the Royal London School of Medicine, Charterhouse Square, London EC1M 6BQ, UK
The therapy of rheumatism began thousands of years ago with the use of decoctions or extracts of herbs or plants such as willow bark or
leaves, most of which turned out to contain salicylates. Following the advent of synthetic salicylate, Felix Hoffman, working at the Bayercompany in Germany, made the acetylated form of salicylic acid in 1897. This drug was named ‘‘Aspirin’’ and became the most widely usedmedicine of all time. In 1971, Vane discovered the mechanism by which aspirin exerts its anti-inflammatory, analgesic and antipyreticactions. He proved that aspirin and other non-steroid anti-inflammatory drugs (NSAIDs) inhibit the activity of the enzyme now calledcyclooxygenase (COX) which leads to the formation of prostaglandins (PGs) that cause inflammation, swelling, pain and fever. However, byinhibiting this key enzyme in PG synthesis, the aspirin-like drugs also prevented the production of physiologically important PGs whichprotect the stomach mucosa from damage by hydrochloric acid, maintain kidney function and aggregate platelets when required. Thisconclusion provided a unifying explanation for the therapeutic actions and shared side effects of the aspirin-like drugs. Twenty years later,with the discovery of a second COX gene, it became clear that there are two isoforms of the COX enzyme. The constitutive isoform, COX-1,supports the beneficial homeostatic functions, whereas the inducible isoform, COX-2, becomes upregulated by inflammatory mediators andits products cause many of the symptoms of inflammatory diseases such as rheumatoid and osteoarthritis.
D 2003 Published by Elsevier Ltd.
Keywords: Aspirin; Cyclooxygenases; Bayer; Inflammation; Thromboxane; Anaphylaxis; Platelets
Aspirin is the most widely used drug in the world. An
many years to treat his arthritis and had recently discovered
aspirin a day doubles the chances of a long life. Studies have
that he could no longer take the drug without vomiting.
shown that a regular dose of aspirin for the over 50s can
Impelled then by filial affection as well as by dedication to
prolong life since aspirin reduces the risk of many diseases
his job, Hoffman searched through the scientific literature
associated with aging. The history of aspirin goes back
and found a way of acetylating the hydroxyl group on the
many thousands of years to the early uses of decoctions or
benzene ring of salicylic acid to form acetylsalicylic acid.
preparations of plants that contain salicylate. Maclagan
After initial laboratory tests, Hoffman’s father was given the
used Salicin, the bitter principle of the common white
drug; it was pronounced effective and later confirmed as
willow, successfully in 1874 to reduce the fever, pain and
such by a more impartial clinical trial.
inflammation of rheumatic fever. Also in 1874, the com-
The name ‘‘Aspirin’’ was given to the new drug by
mercial organic synthesis of salicylic acid was formulated
Bayer’s chief pharmacologist, Heinrich Dreser who was
by Kolbe and his colleagues and led to the founding of the
anxious to find a name that could not possibly be confused
with salicylic acid. At least two accounts are given for
The success of salicylic acid prompted the pharmaceuti-
Dreser’s choice of name; some authorities maintain that the
cal manufacturing house of Frederick Bayer to actively
drug was named after St Aspirinius, an early Neapolitan
search for a derivative of comparable or better efficacy to
bishop who was the patron saint against headaches. A more
salicylic acid. Arthur Eichengru¨n, head of the chemical
prosaic explanation is that the name was derived from
research laboratories at Bayer in 1895, assigned this task
Spiraea, which is the Linnaean name for the genus of plants
to a young chemist named Felix Hoffman. Hoffman also
to which meadowsweet belongs. Meadowsweet contains
had personal reasons for wanting a more acceptable salicylic
salicylaldehyde, which can be oxidised to salicylic acid.
acid derivative; his father had been taking salicylic acid for
According to this explanation, the acid derived from Spi-raea became ‘‘Spirsau¨re’’ in German. Acetylation of Spir-sau¨re produced ‘‘Acetylspisau¨re’’, which was soon
* Corresponding author. Tel.: +44-207-882-6179; fax: +44-207-882-
0049-3848/$ - see front matter D 2003 Published by Elsevier Ltd.
J.R. Vane, R.M. Botting / Thrombosis Research 110 (2003) 255–258
Of course, it is quite possible that Dreser was aware of
glandin (PGs) researchers. Piper and Vane used isolated
both possible derivations and that the ambiguous name was
lungs perfused with Krebs’ solution from sensitised guinea
a deliberate and felicitous contrivance. Of interest,
pigs. The purpose was to detect substances released during
‘‘Euˆsparin’’ was suggested in the original document as an
the anaphylactic reaction, including histamine and SRS-A,
both of which had been known for many years as possiblemediators of anaphylaxis.
They used the technique of continuous bioassay with the
1. Early explanations for the action of aspirin
cascade bioassay system developed by Vane in themiddle 1960s for use with blood or artificial salt solution.
Before 1971, little was known about the real mechanism
As expected, Piper and Vane found the release during
of action of aspirin-like drugs. They produced an anti-
anaphylaxis of histamine and SRS-A, but they also found
inflammatory effect that was qualitatively and quantitatively
some previously unreported substances: PGs, (mainly PGE2
different from that of the anti-inflammatory steroids, and
but some PGF2a) and another, very ephemeral substance
their analgesic action was of a different nature than that
that they called ‘‘rabbit aorta contracting substance’’ (RCS)
produced by opiates. Aspirin-like drugs are weak analgesics
based on the assay tissue that identified it. In the lung
compared with ‘‘strong’’ narcotic analgesics like morphine.
perfusate RCS had a half-life of about 2 min; even when
They are effective in clinical pain of low or moderate but
cooled to a few degrees above freezing, it remained stable
not high intensity such as postoperative pain, osteoarthritis,
for no more than 20 min. It was identified in 1975 as
rheumatoid arthritis, ankylosing spondilytis and some forms
of headache Aspirin-like drugs are effective in experi-
It was RCS that provided the first clue to the relation
mental models involving the induction of a previous in-
between aspirin and the PGs. In the course of further
flammatory state and block the delayed stretching response
experiments involving RCS, Piper and Vane discovered that
induced with an intraperitoneal injection of phenylbenzo-
in some preparations RCS was released by bradykinin. This
quinone or dilute acetic acid in mice. They are not effective
suggested that aspirin’s ability to minimise some effects of
against nociception of short duration induced by pinching or
bradykinin might be due to its blocking of RCS release. This
stimulating the tail or toes of mouse, rat or guinea pig.
idea was confirmed when Piper and Vane presented
Guzman et al. and Lim et al. provided definitive
experimental evidence that the release of RCS from isolated
evidence of the peripheral analgesic activity of aspirin-like
guinea pig lungs during anaphylaxis was blocked by aspirin.
drugs. What then does aspirin do in the periphery to decrease
These guinea pig lung experiments also indicated that
nociception or pain? Many biochemical effects of aspirin-
whenever aspirin blocked RCS release, there was a smaller
like drugs have been documented and theories based on these
contraction of the tissues that assayed PGs and a self-
effects have been abandoned. It was observed, for example,
evident reduction in PG output after aspirin.
that most of these drugs uncoupled oxidative phosphoryla-
The natural result of these experiments was to move the
tion and that several salicylates inhibited dehydrogenase
focus of Vane’s attention from RCS toward PGs. ‘‘While I
enzymes, particularly those dependent on pyridine nucleo-
was writing a review paper over the weekend’’, he recalled,
tides. Some aminotransferases and decarboxylases were also
‘‘including the results of some of these experiments, a
inhibited, as were several key enzymes involved in protein
thought occurred to me that perhaps should have been
and RNA biosynthesis. All of these inhibitory actions
obvious earlier on. In all these experiments (and in those
were at some time invoked to explain the therapeutic actions
of many other workers), the ‘release’ of PGs must in fact
of aspirin. A problem with most of these theories was that the
amount to fresh synthesis of PGs. That is, PG output in
concentration of the drug required for enzyme inhibition was
these experiments, though very low, was still far higher than
in excess (sometimes greatly in excess) of the concentration
the tissues’ initial content of the hormones. Evidently, then,
typically found in the plasma after therapy, and there was
the various stimuli, mechanical and chemical, which re-
invariably a lack of correlation between the ability of these
leased PGs, were in fact ‘turning on’ the synthesis of these
drugs to inhibit particular enzymes and their activities as
compounds. A logical corollary was that aspirin might well
anti-inflammatory agents. Perhaps the most serious imped-
iment of all to acceptance of any of the above ideas was that
Vane immediately tested this exciting idea on the
their proponents could not provide a convincing reason why
following Monday morning. In the absence of ram seminal
inhibition of any of these enzymes should produce the anti-
vesicles, from which the synthetase enzyme was usually
inflammatory, analgesic and antipyretic effects of aspirin.
obtained, he used the supernatant of a broken cell ho-mogenate from guinea pig lung, the same kind of prepa-ration in which A
detected the generation of PGE2 and PGF2a in 1965.
Aliquots of the supernatant were incubated with arachi-
It was against this background of knowledge that the
donic acid and different concentrations of aspirin, indo-
investigation of aspirin’s action was taken over by prosta-
methacin or sodium salicylate. PGF2a generation was
J.R. Vane, R.M. Botting / Thrombosis Research 110 (2003) 255–258
estimated by bioassay after 30 min of incubation at 37 jC.
There was a dose-dependent inhibition of PG formation byall three drugs, indomethacin being the most potent and
A homogeneous, enzymatically active cyclooxygenase
sodium salicylate the least. Three other drugs, morphine (an
(COX) or prostaglandin endoperoxide synthase (PGHS) was
opiate analgesic), hydrocortisone (a steroidal anti-inflamma-
isolated in 1976 This membrane-bound hemoprotein
tory) and mepyramine (an antihistamine), had little or no
and glycoprotein with a molecular weight of 72 kDa is
found in greatest amounts in the endoplasmic reticulum of
Vane published the results of these experiments in
prostanoid-forming cells It exhibits COX activity that
Nature in 1971. Two other reports in the same issue lent
both cyclizes arachidonic acid and adds the 15-hydroperoxy
support to his findings and extended them considerably.
group to form PGG2. The hydroperoxy group of PGG2 is
Both studies originated from the same department, and by
reduced to the hydroxy group of PGH2 by a peroxidase that
coincidence, one of these stemmed from an entirely inde-
uses a wide variety of compounds to provide the requisite
pair of electrons. Both COX and hydroperoxidase activities
Smith and Willis were investigating the effects of
are contained in the same dimeric protein molecule.
aspirin on platelet behaviour. Venous blood samples were
Aspirin selectively acetylates the hydroxyl group of one
obtained from three colleagues before and 1 h after taking
serine residue (Ser 530) located 70 amino acids from the C
600 mg of aspirin orally. Platelets were isolated, washed and
terminus of the enzyme Acetylation leads to irrevers-
incubated with thrombin and the supernatant was tested for
ible COX inhibition; thus, a new enzyme must be synthe-
the presence of various substances including PGs. No
sized before more prostanoids are produced. When the
consistent changes were seen in the release of any of the
purified enzyme is acetylated, only the COX, not the hydro-
substances except the PGs, which were substantially
peroxidase, activity is inhibited. The stoichiometry of this
inhibited after aspirin. Indomethacin also blocked PG re-
reaction is 1:1, with one acetyl group transferred per enzyme
lease when taken orally or when added directly to the
monomer of this dimeric protein. At low concentrations,
aspirin acetylates PGHS rapidly (within minutes) and selec-
The importance of this study lay in its demonstration that
tively. At high concentrations, over longer time periods,
these drugs were active not only in guinea pig lungs in vitro
aspirin will also non-specifically acetylate a variety of
but also in humans, in platelets and after oral administration.
proteins and nucleic acids Acetylation of the enzyme
In other words, the aspirin effect was not restricted by
by aspirin places a bulky substituent on the Ser 530 oxygen
species, tissue or route of administration. These conclusions
that inhibits binding of arachidonic acid
derived support from the final type of experiment reportedin that issue of Nature. Ferreira et al. demonstrated thatthe aspirin-like drugs blocked PG release from the perfused,
isolated dog spleen. In the same year, Collier and Flowerreported in Lancet that administration of aspirin
By the late 1980s, several reports appeared that the
inhibited human seminal PG production.
synthesis of PGHS could be stimulated by growth factors,tumour promoters, interleukin-1 lipopolysaccharideand tumour necrosis factor. Interleukin-1 exerted its effect
3. Correlation of anti-enzyme activity of aspirin with its
during the transcriptional rather than during the translational
phase of induced synthesis of PGHS Induction ofPGHS gene expression by serum factors occurred after
The major importance of these findings was that they
approximately 2 h in mouse 3T3 cells, in which PGs are
provided a simple explanation of the manner in which
essential for cell division. These reports culminated with the
aspirin-like drugs exerted their therapeutic actions. When
discovery by Dan Simmons of a second, distinct COX
the reports were published in 1971, there was already
gene which could be induced with mitogens, growth factors,
evidence suggesting that PGE1 was an extremely potent
tumour promoters and lipopolysaccharide, and the induction
pyretic agent in several species and that PGE1 or PGE2
of which could be inhibited with glucocorticoids. This gene
mimicked the inflammatory response when injected intra-
expresses COX-2 which elaborates PGs, mostly PGE2,
dermally. PGs had also been detected in inflammatory
during inflammatory reactions in contrast to COX-1, which
exudates so there were grounds for speculating that
produces PGs involved in physiological processes such as
PGs might be responsible, at least in part, for the genesis of
protection of the stomach mucosa, platelet aggregation and
fever or inflammation and that the aspirin-like drugs might
owe their therapeutic activity to their ability to prevent PG
There is 60% homology between the amino acid struc-
biosynthesis. Certainly, as Flower et al. pointed out, the
tures of COX-1 and COX-2 and aspirin binds to Ser 516 in
concentrations of these drugs required to inhibit synthesis
the active site of COX-2 in the same way as it binds to Ser
were within the plasma levels found during therapy, even
530 in the active site of COX-1. However, the active site of
when protein binding was taken into account.
COX-2 is slightly larger than the active site of COX-1, so
J.R. Vane, R.M. Botting / Thrombosis Research 110 (2003) 255–258
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Publikationen aus dem Pathologischen Institut der Universität Würzburg in 1999 Avots, A., Buttmann, M., Chupvilo, S., Escher, C., Smola, U., Bannister, A.J., Rapp, U.R., Kouzarides, T., Serfling, E. CBP/p300 integrates Raf/Rac-signalling pathways in the transcriptional induction of NF-Atc during T cell activation Immunity 10: 515-524 (1999) Chirmule, N., Avots, A., LakshmiTamma, S.M.,
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