EDWIN L. COOPER, PHD, SCD
Earthworms have a long and provocative association with medicine. They are used as a remedy for smallpox in Burma and Laos, while in Iran earthworms are eaten with bread in order to expel bladder stones. Closer to home, the Nanticoke Indians of Delaware use them to relieve pain associated with rheumatism (J Am Folklore 14:30-38, 1901; J Wash Acad Sci 41:229-235, 1951).
Earthworms still have a place in the modern world of alternative medicine, most notably as a potential form of cancer treatment. Their curative power may lie in the fact that earthworms, like many invertebrates, are immune to malignant disease (J Natl Cancer Inst 31:655-669, 1969).
Indeed, the cells of the earthworm's immune system have shown an ability to actually kill cancer cells. In one study, the cancer cell K562 was grown cultured with immunopotent earthworm cells. The small cells of the latter instantaneously recognized the foreign cancer cells, threw out their voracious false feet (pseudopodia), and began the process of devouring, pulling, and chewing, leading to cell death. Next, a larger cell mops up the battle-scarred terrain, much as monocytes and neutrophils do during inflammation in humans (Endeavor 4:160-165, 1981; Immunology of Annelids, CRC Press, Boca Raton, Fla., 1994; Cell Immun 166:113-122, 1995; Exp Cell Res 224:174-182, 1996; Eur J Cell Biol 70:278-288, 1996).
This groundbreaking in vitro approach has inspired further research using human, canine, and rodent in vivo systems. The primary goal is to identify the molecule or molecules in earthworm cells that are responsible for cellular confrontation. Moreover, there is a multitude of factors that drive earthworm-mediated response to explore, such as the composition of earthworms themselves, their molecular mechanism, and variability within species.
Killing cancer by humoral mediation
Based on research done in Asia and Europe, one factor that may inhibit the spontaneous growth of tumors is lombricine, which is a phosphagen unique to earthworms. In 1991, investigators at Meiji University in Kanagawa, Japan, analyzed the effects of lombricine, extracted and purified from earthworm skin (Lumbricus terrestris), on the growth of palpable, approximately 5 mm, spontaneous mammary tumors in SHN mice.
In the first experiment, daily subcutaneous injections of lombricine (0.3 mg in 0.05 mL olive oil) were found to markedly inhibit the growth of tumors, and were associated with the retardation of the growth of preneoplastic mammary hyperplastic alveolar nodules. In 1H-NMR spectra, the experimental mice had lower serum levels of lactic acid and glucose than controls. By contrast, urine of the experimental group in the above study contained higher levels of allantoin, creatine, and creatinine.
In the second experiment, lombricine given as a dietary supplement (120 mg/kg) also inhibited tumor growth, although less significantly than after injection. This treatment exerted little effect on 1H-NMR spectra of either serum or urine and normal and preneoplastic mammary gland growth (Anticancer Res 11:1061-1064, 1991).
When viewed critically, these results suggest that inhibition by lombricine of mammary tumor growth is at least partly due to the maintenance of homeostasis of the body. This includes regulation of excess glucose uptake as a source of energy and nutrition.