A R T I C L E
Aspirin, brain, and cancer
When a drug such as caffeine or aspirin turns out to have a great variety of protective effects, it's important to understand what it's doing.
Because aspirin has been abused by pharmaceutical companies that have competing products to sell, as well as by the original efforts to pro-mote aspirin itself, people can easily find reasons why they shouldn't take it.
Early in the 20th century, people were told that fevers were very bad, and that aspirin should be used whenever there is a fever.
In the 1980s, there was a big publicity campaign warning parents that giving aspirin to a child with the flu could cause the potentially deadly Reye syndrome. Aspirin sales declined sharply, as sales of acetaminophen (Tylenol, etc.) increased tremendously. But in Australia, a study of Reye syndrome cases found that six times as many of them had been using acetaminophen as had used aspirin. (Orlowski, et al., 1987)
Until the 1950s and 1960s, when new products were being promoted, little was said about the possibility of stomach ulceration from aspirin. Lately, there has been more publicity about the damage it can do to the stomach and intestine, much of it in connection with the sale of the new "COX-2 inhibitors." (These new drugs, rather than protecting the circulatory system as aspirin does, damage it.) Aspirin rapidly breaks down into ace-tic acid and salicylic acid (which is found in many fruits), and salicylic acid is protective to the stomach and intestine, and other organs. When aspirin was compared with the other common anti-imflammatory drugs, it was found that the salicylic acid it releases protects against the damage done by another drug. (Takeuchi, et al, 2001; Ligum-sky, et al., 1985.) Repeated use of aspirin protects the stomach against very strong irritants. The ex-periments in which aspirin produces stomach ulcers are designed to produce ulcers, not to realistically model the way aspirin is used.
Recently, the public has been led to believe that drugs are being designed to fit certain cellular "receptors." The history of the "COX-2 inhibitors" is instructive, in a perverse way. The structures of DES and other synthetic estrogens were said to relate to "the estrogen receptor." Making these estrogenic molecules more soluble in water made them somewhat anti-estrogenic, leading to products such as Tamoxifen. But some of the molecules in this group were found to be anti-inflammatory The structure of Celecoxib and other "COX-2 inhibitors" is remarkably similar to the "designer estrogens." Considering this, it's a little odd that so few in the U.S. are openly discussing the possibility that estrogen's function is directly related to inflammation, and involves the production of many inflammatory mediators, including COX-2. (See Lerner, et al., 1975; Luo, et al., 2001; Cushman, et al, 2001; Wu, et al., 2000; Herrington, et al., 2001.)
Soot and smoke contain many chemicals that produce inflammation (Brune, et al., 1978). In the 1930s, soot was known to be both carcinogenic and estrogenic, and analysis of its components led to the production of the early commercial estrogens. Any intelligent person reading the chemical and biological publications of that time will see how closely associated cancer, inflammation, and estrogen are.
Soon after vitamin E was discovered, tocopherol was defined as a brain-protective, pregnancy protective, male fertility protective, anti-thrombotic, anti estrogenic agent. But very soon, the estrogen industry made it impossible to pre-sent ideas that explained vitamin E, progesterone, vitamin A, or thyroid hormone in terms of the protection they provide against estrogenic sub-stances. Since the polyunsaturated fats caused the same conditions that were caused by unopposed estrogen, vitamin E came to be known as an "antioxidant," because it reduced their toxicity. (Vitamin E is now known to suppress COX-2, synergizing with aspirin and opposing estrogen.)
In 1970, when I was beginning to see the ways in which unopposed estrogen and accumulated polyunsaturated fats interacted with a vitamin E deficiency during aging and in infertility, I got some prostaglandins to experiment with, since they are products of the oxidation of linoleic acid. The prostaglandins are an interesting link between estrogens and inflammation, in normal physiology as well as in disease.
I wanted to test their effects on the uterus, especially the sites where the embryos implant. There was a theory that the electrical charge of the surface of the uterus was decreased at the implantation sites, to reduce the repulsion between two negatively charged things. Although there were regions of lower surface charge along the lining of the uterus, the charge changed as waves of muscle contraction moved along the uterus, and the prostaglandins affected the contractions.
To understand the differences between the different types of prostaglandin, I tested them on my arm, and those with the most hydroxyl groups produced regions with an increased negative charge. For comparison, I exposed another spot to sunlight for an hour, and found that there was a similar increase in the negative charge in that spot. Apparently the prostaglandins were causing an injury or excitation, a mild inflammation, in the skin cells.
A few years later, aspirin was found to inactivate the enzyme that forms prostaglandins, by the transfer of the acetyl radical to the enzyme. This became the orthodox "explanation" for what aspirin does, though it neglected to explain that salicylic acid (lacking the acetyl radical) had been widely known in the previous century for its very useful anti inflammatory actions. The new theory did explain (at least to the satisfaction of editors of medical magazines) one of aspirin's effects, but it distracted attention from all the other effects of aspirin and salicylic acid.
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Neurosci Lett 2000 Aug 11;289(3):201-4. Ibuprofen protects dopaminergic neurons against glutamate toxicity in vitro. Casper D, Yaparpalvi U, Rempel N, Werner P. "We examined the effects of aspirin, acetaminophen, and ibuprofen on cultured primary rat embryonic neurons from mesencephalon, the area primarily affected in Parkinson's disease. We evaluated whether these drugs protect dopaminergic neurons against excitotoxicity. All three NSAIDs significantly attenuated the decrease in dopamine uptake caused by glutamate, indicating preservation of neuronal integrity."
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J Clin Endocrinol Metab 2001 Sep; 86(9):4216-22. Differential effects of E and droloxifene on C-reactive protein and other markers of inflammation in healthy postmenopausal women. Herrington DM, Brosnihan KB, Pusser BE, Seely EW, Ridker PM, Rifai N, MacLean DB. "E treatment resulted in 65.8% higher levels of C-reactive protein (P = 0.0002) and 48.1% higher levels of IL-6...." "These data provide additional evidence of a proinflammatory effect of E that may have adverse cardiovascular consequences."
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J Cardiovasc Pharmacol 1995 Feb;25(2):273-81. Inhibitory effects of aspirin on coronary hyperreactivity to autacoids after arterial balloon injury in miniature pigs. Kuga T, Ohara Y, Shimokawa H, Ibayashi S, Tomoike H, Takeshita A. "Coronary vasoconstriction induced by histamine and serotonin were examined angiographically before, 1 h, 1 week, and 1 month after balloon injury in 29 hypercholesterolemic miniature pigs." "Hyperconstriction induced by the autacoids 1 h after injury were significantly less in groups B and C than in group A (p < 0.01). Hyperconstriction induced by autacoids 1 week after injury were significantly less in group B than in group A (p < 0.01) and were significantly less in group C than in group A (p < 0.01) or group B (p < 0.05)."
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Neuropharmacology 2000 Apr 27;39(7):1309-18. Mechanisms of the neuroprotective effect of aspirin after oxygen and glucose deprivation in rat forebrain slices. Moro MA, De Alba J, Cardenas A, De Cristobal J, Leza JC, Lizasoain I, Diaz-Guerra MJ, Bosca L, Lorenzo P "Apart from its preventive actions against stroke due to its antithrombotic properties, recent data in the literature suggest that high concentrations of ASA also exert direct neuroprotective effects." "We have found that ASA inhibits neuronal damage at concentrations lower than those previously reported (0.1-0.5 mM), and that these effects correlate with the inhibition of excitatory amino acid release, of NF-kappaB translocation to the nucleus and iNOS expression caused by ASA." "Our results also show that the effects of ASA are independent of COX inhibition. Taken together, our present findings show that ASA is neuroprotective in an in vitro model of brain ischaemia at doses close to those recommended for its antithrombotic effects."
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J Physiol Paris 2001 Jan-Dec;95(1-6):51-7. Protection by aspirin of indomethacin-induced small intestinal damage in rats: mediation by salicylic acid. Takeuchi K, Hase S, Mizoguchi H, Komoike Y, Tanaka A. "Most of non-steroidal anti-inflammatory drugs (NSAIDs) except aspirin (ASA) produce intestinal damage in rats." "ASA did not provoke any damage, despite inhibiting (prostaglandin) PG production, and prevented the occurrence of intestinal lesions induced by indomethacin, in a dose-related manner."
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(three per cent) were recorded following acetylsalicylic acid treatment, as compared to the control group (91 and nine per cent)."
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