Friday, July 02, 2010

Kathy Archibald, London, UK, questions the value of vivisection for translating bench research to bedside

Vivisection value

Simon Festing says that reducing publication bias in animal research would ensure a sound basis to move from animal studies into clinical trials (5 June, p 22).
This would be true if the results of animal studies translate directly to humans. They do not, which is a far more important problem than publication bias.
Full publication of every animal study of the immunomodulatory drug TGN1412, for example, would still have suggested that it was safe to proceed to clinical trials, since the devastating response to the drug is unique to humans.
Systematic reviews of the applicability of animal results to human medicine - such as those by Pablo Perel and others (BMJ, vol 334, p 197) and by Daniel Hackam and Donald Redelmeier (The Journal of the American Medical Association, vol 296, p 1731) show consistently that animal studies predict human response incorrectly a majority of the time. In the case of stroke, is anyone seriously suggesting that more than 150 treatments successful in animals have failed in humans because of publication bias?
Of course, this bias should be addressed. There should unquestionably be a registration system for animal studies, as there is for human studies. As chief executive of Understanding Animal Research, surely Festing should be calling for this, rather than merely commenting that "it is not inconceivable that we might move towards a similar system".
From Marshall Deutsch
In her article "Eat less, live longer?", Laura Cassiday points out that followers of a restricted diet mostly "hover around the lower limit of 'normal' body mass index [BMI], at 18.5 kilograms per height-in-metres squared" and have low cholesterol levels (29 May, p 36).
However, many studies, such as that by Katherine Flegal and colleagues in the The Journal of the American Medical Association (vol 293, p 1861), show that mortality associated with weight is at a minimum in people with a BMI of 25 to 29.9, a range considered overweight.
Similarly, many studies show that older people with high blood cholesterol live longer than those with low blood cholesterol. One example is the upcoming work by Päivi Tuikkala, of the University of Eastern Finland in Kuopio, and colleagues, who conclude: "Participants with low serum total cholesterol seem to have a lower survival rate than participants with an elevated cholesterol level, irrespective of concomitant diseases or health status" (Scandinavian Journal of Primary Health Care, vol 28, p 121).
But don't animal studies show that dietary restriction leads to a longer life? Yes, if those little furry prisoners are denied exercise privileges. Jean Mayer, in his book Overweight: Causes, cost, and control, showed rats that exercised from 1 to 8 hours per day and were allowed to eat all they wanted, ate in proportion to their caloric needs. Rats that exercised for less than an hour per day consumed calories at a rate inversely proportional to their level of activity. Thus, the health and longevity of sedentary lab rats might be expected to increase if their diets were restricted. This need not be true of rats - or, by extension, humans - that are able or required to exercise.
Sudbury, Massachusetts, US
Safer Medicines Campaign

2 comments:

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