Effet cardioprotecteur de la mélatonine par rapport à la vitamine D chez les patientes atteintes d'un cancer du sein recevant de la doxorubicine

Doxorubicin is one of the most potent chemotherapeutic agents and is widely used for the treatment of various cancers and hematological malignancies . Although Doxorubicin has a potential beneficial effect in cancer treatment, its dose-dependent cardio toxicity is considered a major challenge.

Doxorubicin is known to generate free radicals either by redox cycling between a semiquinone form and a quinone form or by forming a Doxorubicin-Fe3+ complex . In both pathways, molecular oxygen is reduced to superoxide ion , which is converted to other forms of reactive oxygen species such as hydrogen peroxide and hydroxyl radical . These free radicals could then cause membrane and macromolecule damage, both of which lead to injury to the heart, an organ that has a relatively low level of antioxidant enzymes such as superoxide dismutase and catalase .

Furthermore, it was revealed that Doxorubicin may enhance the death of cardiomyocytes by affecting the tumor necrosis factor signaling pathway via increasing the expression and levels of inflammatory genes interleukin and interleukin -6 .

To alleviate DOX-induced toxicity, researchers have tested a number of strategies, including the administration of antioxidants and/or antiapoptotic agents, in both in vitro and in vivo models of Doxorubicin induced cytotoxicity, but most of these trials have failed to translate into clinical benefits . As a result, there are no effective approaches for alleviating Doxorubicin induced cytotoxicity despite intensive research over recent decades .

Melatonin is a natural hormone that is primarily secreted by the pineal gland and functions as a major regulator of circadian rhythms in humans . Melatonin also plays a variety of biological roles as a modulator of mood, sexual behavior and sleep; low levels or a deficiency of melatonin are also associated with Parkinson's disease, Alzheimer's disease, epilepsy, ischemic injury, diabetes, and even cancer .

Melatonin has emerged as a promising adjuvant that protects against doxorubicin-induced cytotoxicity, as highlighted by various studies and clinical trials that have demonstrated cardioprotective effects against several chemotherapeutic agents . Moreover, melatonin exhibits low toxicity and easily enters cells owing to its good solubility in both aqueous and organic phases and its highly lipophilic properties . Vitamin D plays an important role in the regulation of body function including the cardiovascular system .

Vitamin D deficiency results in the decrease of active calcitriol leading to inhibition of proliferation of cardiomyocytes and vascular smooth muscles .

This study aims to assess the cardioprotective effect of melatonin and vitamin D in breast cancer patients who receive doxorubicin.