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Table of Contents
Overview
General Information
History
Laboratory/Animal/Preclinical Studies
Human/Clinical Studies
Adverse Effects
Overall Level of Evidence for Coenzyme Q10
Changes to This Summary (01/11/2005)
More Information
History of Coenzyme Q10
Coenzyme Q10 was first isolated in 1957, Reviewed in [1] and its chemical structure (benzoquinone compound) was determined in 1958. Reviewed in [2] Interest in coenzyme Q10 as a therapeutic agent in cancer began in 1961, when a deficiency was noted in the blood of both Swedish and American cancer patients, especially in the blood of patients with breast cancer.[2] Reviewed in [3,4] A subsequent study showed a statistically significant relationship between the level of plasma coenzyme Q10 deficiency and breast cancer prognosis.[5] Low blood levels of this compound have been reported in patients with malignancies other than breast cancer, including myeloma, lymphoma, and cancers of the lung, prostate, pancreas, colon, kidney, and head and neck.[2,6] Reviewed in [7] Furthermore, decreased levels of coenzyme Q10 have been detected in malignant human tissue,[8-12] but increased levels have been reported as well.[8]
A large amount of laboratory and animal data on coenzyme Q10 has accumulated since 1962. Reviewed in [2] Research into cellular energy-producing mechanisms that involve this compound was awarded the Nobel Prize in chemistry in 1978. Some of the accumulated data show that coenzyme Q10 stimulates animal immune systems, leading to higher antibody levels,[13] greater numbers and/or activities of macrophages and T cells (T lymphocytes),[13,14] and increased resistance to infection.[15-17] Coenzyme Q10 has also been reported to increase IgG (immunoglobulin G) antibody levels and to increase the CD4 to CD8 T-cell ratio in humans.[18-20] CD4 and CD8 are proteins found on the surface of T cells, with CD4 and CD8 identifying helper T cells and cytotoxic T cells, respectively; decreased CD4 to CD8 T-cell ratios have been reported for cancer patients.[21,22] Research subsequently delineated the antioxidant properties of coenzyme Q10.[23,24] Reviewed in[25-27]
Proposed mechanisms of action for coenzyme Q10 that are relevant to cancer include its essential function in cellular energy production and its stimulation of the immune system (which may both be related), as well as its role as an antioxidant. Coenzyme Q10 is essential to aerobic energy production, Reviewed in [1,25,28] and it has been suggested that increased cellular energy leads to increased antibody synthesis in B cells (B lymphocytes).[6,18] As noted previously (General Information section), coenzyme Q10 can also behave as an antioxidant. Reviewed in [1,25-27,29-32] In this capacity, coenzyme Q10 is thought to stabilize cell membranes (lipid-containing structures essential to maintaining cell integrity) and to prevent free radical damage to other important cellular components. Reviewed in [1,25,27,32] Free radical damage to DNA (and possibly to other cellular molecules) may be a factor in cancer development. Reviewed in [11,23,30,33-36]
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