EL CIENTÍFICO DE LA SEMANA: Profesor Damián García Olmo

Ponemos esta deliciosa carta que el Profesor Damián García Olmo publicó en el año2003 en la prestigiosa revista The New England Journal of Medicine y la réplica que hace la Dra. Nadia Rosenthal.

 

The Vulture and Stem Cells

N Engl J Med 2003; 349:1480-1481

Damian Garcia-Olmo, M.D., Ph.D.
Universidad Autonoma de Madrid, 28046 Madrid, Spain damian.garcia@uam.es

Rosenthal (July 17 issue) begins her article by considering the myth of Prometheus. She says that a vulture preyed daily on his self-renewing liver. Indeed, Greek mythology tells us that a bird ate Prometheus's liver, but older sources allude to an eagle instead of a vulture (Prometheus Attacked by Zeus's Eagle.). This is not a trivial point, because vultures are scavengers, whereas eagles are birds of prey. Vultures would never eat living animals. This cultural imprecision might seem unimportant, but terminology is key with respect to the issue of the “stem-cell promise.” Semantic differences between terms such as “nuclear transfer” and “therapeutic cloning”are very important.

To continue the theme of Greek mythology, we suggest the myth of Phaethon. Helios (the Sun) drove his scalding carriage through the skies every day. Having made insistent requests, Phaethon, Helios's young and inexpert son, managed to drive the chariot for a day, but he could not stop the runaway horses, whose path threatened to burn the Earth. Annoyed, Zeus struck Phaethon with a lightning bolt. Since adult stem cells appear to show clinical safety and feasibility, it should be noted that other sources of cell therapy could be dangerous, at least until we have wider knowledge about how to control them.

Dr. Rosenthal replies: I commend my colleagues for their careful perusal of the ancient literature, having correctly identified two sources of the Greek legend where an eagle, probably a symbol of Zeus himself, was sent to torture the Titan Prometheus. As noted by other scholars, the Promethean tale resembles one described in Homer's Odyssey, in which Tityos is tormented by two vultures and may have been the original victim of this punishment.

An earlier legend holds precedence in the Caucasus, where earthquakes were allegedly caused by the struggles of a fierce giant, fettered in a mountain cave for his various impieties while a vulture pecked intermittently at his bowels. Perhaps it was this ancient version to which Bulfinch's The Age of Fable alludes in describing Prometheus “chained to a rock on Mount Caucasus, where a vulture preyed on his liver.” Other literary figures, including Byron, have also described the vulture of Promethean legend.

As for the argument that vultures never eat live flesh, this is not strictly true. They are omnivorous, feeding chiefly on carrion because they have relatively weak beaks and lack the strength of other birds of prey. They rarely attack live prey unless it is rendered helpless. One might argue that Prometheus was defenseless against the attacks of emboldened raptors, but the true ornithologic identity of his devourer remains enshrouded in the mists of myth. Let us hope that as scientists we leave less indeterminate the documentation of the illusive stem cell's true identity.

(I am indebted to Professor Brian Bothwick, Department of Classics and Ancient History, University of Western Australia, for his invaluable tutelage and for the use of his excellent library.)

Nadia Rosenthal, Ph.D.
European Molecular Biology Laboratory, 00016 Monterotondo, Italy