What do they do?
Thymus extracts are extracts derived from the thymus glands usually of young calves
(bovine). The thymus is one of our major immune
system glands. It is composed of two soft pinkish-gray lobes lying in bib-like fashion
just below the thyroid gland and above the heart. To a large extent, the health of the thymus
determines the health of the immune system. The thymus is responsible for many immune system
functions, including the production of T lymphocytes, a type of white blood cell responsible
for "cell-mediated immunity." Cell-mediated immunity refers to immune mechanisms not
controlled or mediated by antibodies. Cell-mediated immunity is extremely important in the
resistance to infection by certain bacteria, yeast (including Candida albicans),
fungi, parasites, and viruses (including herpes simplex, Epstein-Barr, and the viruses that cause
hepatitis). Cell-mediated immunity is also critical in
protecting against the development of cancer, allergies, and autoimmune disorders such as rheumatoid arthritis. The thymus gland also releases
several hormones, such as thymosin, thymopoeitin, and serum thymic factor, that regulate many
immune functions.
The oral calf thymus extract that has been studied scientifically is specially prepared to
concentrate small protein-like molecules (polypeptides). This extract (known as
Thymomodulin®) has been shown effective in preventing recurrent upper respiratory tract
infections.
Preliminary studies suggest that Thymomodulin may also be helpful in (1) improving one of
the T-cell defects in patients with human immunodeficiency virus infection (HIV—the virus that causes AIDS); (2) treating acute and
chronic hepatitis B infections; (3) restoring the
number of peripheral white blood cells in cancer
patients undergoing chemotherapy or radiation; and (4) relieving allergies, including
asthma, hay fever, and food allergies, in
children.1 2 The effectiveness of Thymomodulin in these conditions may
be the result of improved thymus gland activity, or it may be due to the presence of hormones
or other biologically active substances in the extract.
The ability of Thymomodulin to improve immune
function and reduce the number of recurrent
infections has been shown in double-blind studies of children and adults with a history of
recurrent respiratory-tract infections.3 4 5 6
7 Thymomodulin has also been shown in a double-blind study to improve immune
function in cases of exercise-induced immune suppression. In addition, preliminary studies
have shown the extract to improve immune function in people with diabetes and in elderly people.8 9
10 11 (Extreme exercise,
diabetes, and aging are all associated with suppression of immune function.)
Preliminary studies in patients with acute or chronic hepatitis suggest that
supplementation with Thymomodulin may be helpful.12 13 However,
additional studies are needed to confirm these findings.
In a preliminary study in patients with early HIV infection, Thymomodulin improved several
measures of immune function, including an increase in the number of T-helper cells, one of the
goals in the treatment of HIV infection.14 Thymomodulin (given orally or by
injection) has been used in cancer patients to
counteract the decline in white-blood-cell levels that can result from chemotherapy or
radiation.15 16 17 18 19 20
In test tube studies, Thymomodulin and other thymus extracts have been shown to exert a number
of effects on white blood cells (e.g., increasing both the bone marrow production and
functional activity of white blood cells).21 22 However, it is not yet
known if this effect can be achieved with the use of oral thymus extracts.
The oral administration of Thymomodulin has been shown in preliminary and double-blind
clinical trials to improve the symptoms and course of hay
fever, allergic rhinitis, asthma, eczema, and food allergies (in conjunction with an allergy elimination
diet).23 24 25 26 27 28
29 30 Presumably, this clinical improvement results from restoring
proper control over immune function.
Thymomodulin given by injection has also been shown to be helpful in the treatment of
diseases of the heart muscle (idiopathic myocarditis and idiopathic dilated cardiomyopathy).31 32 It is not
known whether oral thymus extracts can achieve these same benefits.
References
1. Cazzola P, Mazzanti P, Bossi G. In vivo modulating effect of a calf
thymus acid lysate on human T lymphocyte subsets and CD4+/CD8+ ratio in the course of
different diseases. Curr Ther Res 1987;42:1011–7.
2. Kouttab NM, Prada M, Cazzola P. Thymomodulin: Biological properties
and clinical applications. Med Oncol Tumor Pharmacother 1989;6:5–9
[review].
3. Fiocchi A, Borella E, Riva E, et al. A double-blind clinical trial for
the evaluation of the therapeutic effectiveness of a calf thymus derivative (Thymomodulin) in
children with recurrent respiratory infections. Thymus 1986;8:831–9.
4. Galli L, de Martino M, Azzari C, et al. Preventive effect of
thymomodulin in recurrent respiratory infections in children. Pediatr Med Chir
1990;12:229–32.
5. Vettori G, Lazzaro A, Mazzanti P, Cazzola P. Prevention of recurrent
respiratory infections in adults. Minerva Med 1987;78:1281–9.
6. Longo F, Lepore L, Agosti E, Panizon F. Evaluation of the
effectiveness of thymomodulin in children with recurrent respiratory infections. Pediatr
Med Chir 1988;10:603–7.
7. Maiorano V, Chianese R, Fumarulo R, et al. Thymomodulin increases the
depressed production of superoxide anion by alveolar macrophages in patients with chronic
bronchitis. Int J Tissue React 1989;11:21–5.
8. Garagiola U, Buzzetti M, Cardella E. Immunological patterns during
regular intensive training in athletes: quantification and evaluation of a preventive
pharmacological approach. J Int Med Res 1995;23:85–95.
9. Wysocki J, Wierusz-Wysocka B, Wykretowicz A, Wysocki H. The influence
of thymus extracts on the chemotaxis of polymorphonuclear neutrophils (PMN) from patients with
insulin-dependent diabetes mellitus (IDD). Thymus 1992;20:63–7.
10. Calsini P, Mocchegiani E, Fabris N. The pharmacodynamics of
thymomodulin in elderly humans. Drugs Exp Clin Res 1985;11:671–4.
11. Braga PC, Dal Sasso M, Maci S, et al. Restoration of
polymorphonuclear leukocyte function in elderly subjects by thymomodulin. J Chemother
1994;6:354–9.
12. Galli M, Crocchiolo P, Negri C, et al. Attempt to treat acute type B
hepatitis with an orally administered thymic extract (Thymomodulin): preliminary results.
Drugs Expt Clin Res 1985;11:665–9.
13. Bortolotti F, Cadrobbi P, Criverllaro C, et al. Effect of an orally
administered thymic derivative, Thymodulin, in chronic type B hepatitis in children. Curr
Ther Res 1988;43:67–72.
14. Valesini G, Barnaba V, Benvenuto R, et al. A calf thymus lysate
improves clinical symptoms and T-cell defects in the early stages of HIV infection: second
report. Eur J Cancer Clin Oncol 1987;23:1915–9.
15. Kouttab NM, Prada M, Cazzola P. Thymomodulin: biological properties
and clinical applications. Med Oncol Tumor Pharmacother 1989;6:5–9
[review].
16. Kang SD, Lee BH, Yang JH, Lee CY. The effects of calf-thymus extract
on recovery of bone marrow function in anticancer chemotherapy. New Med J
1985;28:11–5.
17. Schulof RS. Thymic peptide hormones: basic properties and clinical
applications in cancer. Crit Rev in Oncol Hematol 1985;3:309–76 [review].
18. Meneses G, Delgado MA, Perez-Machado A, et al. Thymostimulin
increases natural cytotoxic activity in patients with breast cancer. Int J
Immunopharmacol 1997;19:187–93.
19. Skotnicki AB. Thymic hormones and lymphokines. Drug Today
1989;25:337–62 [review].
20. Ernst E. Thymus therapy for cancer? A criteria-based, systematic
review. Eur J Cancer 1997;33:531–5 [review].
21. Vasilopoulos G, Porwit A, Lauren L, et al. The effect of a calf
thymus acid lysate on bone marrow cell growth in vitro. Immunopharmacol Immunotoxicol
1988;10:523–36.
22. Skotnicki AB. Thymic hormones and lymphokines. Drug Today
1989;25:337–62 [review].
23. Cazzola P, Mazzanti P, Bossi G. In vivo modulating effect of a calf
thymus acid lysate on human T lymphocyte subsets and CD4+/CD8+ ratio in the course of
different diseases. Curr Ther Res 1987;42:1011–7.
24. Kouttab NM, Prada M, Cazzola P. Thymomodulin: biological properties
and clinical applications. Med Oncol Tumor Pharmacother 1989;6:5–9
[review].
25. Marzari R, Mazzanti P, Cazzola P, Pirodda E. Perennial allergic
rhinitis: prevention of the acute episodes with Thymomodulin. Minerva Med
1987;78:1675–81.
26. Genova R, Guerra A. A thymus extract (thymomodulin) in the prevention
of childhood asthma. Pediatr Med Chir 1983;5:395–402.
27. Bagnato A, Brovedani P, Comina P, et al. Long-term treatment with
thymomodulin reduces airway hyperresponsiveness to methacholine. Ann Allergy
1989;62:425–8.
28. Fiocchi A, Grasso U, Travaglini P, et al. A double blind clinical
trials on the effectiveness of a thymic derivative (Thymomodulin) in the treatment of children
with atopic dermatitis. Int J Immunother 1987;3:279–84.
29. Cavagni G, Piscopo E, Rigoli E, et al. Food allergy in children: an
attempt to improve the effects of the elimination diet with an immunomodulating agent
(thymomodulin). A double-blind clinical trial. Immunopharmacol Immunotoxicol
1989;11:131–42.
30. Genova R, Guerra A. Thymomodulin in management of food allergy in
children. Int J Tissue React 1986;8:239–42.
31. Miric M, Vasiljevic J, Bojic M, et al. Long-term follow up of
patients with dilated heart muscle disease treated with human leucocytic interferon alpha or
thymic hormones initial results. Heart 1996;75:596–601.
32. Miric M, Miskovic A, Brkic S, et al. Long-term follow-up of patients
with myocarditis and idiopathic dilated cardiomyopathy after immunomodulatory therapy.
Immunol Med Microbiol 1994;10:65–74.
