Cancer cachexia is a complex catabolic state in patients with a malignancy, associated with increased morbidity and mortality.
This syndrome is characterized by a redistribution of the body’s protein content and a subsequent muscle wasting. The aetiology of this
syndrome seems multifactorial, but remains unclear. It is suggested that this catabolic state occurs in response to the alterations in immune
interactions between tumor and host. The amino acid arginine and its derivate nitric oxide (NO) play various roles in anti-tumor
immune response and the body’s homeostasis. Glutamine is the precursor for arginine de novo synthesis and the most abundant amino
acid in the body, mainly stored in skeletal muscle. Tumors develop a protection mechanism against the specific anti-tumor attack of the
immune system by recruiting myeloid derived suppressor cells (MDSC). The MDSC deplete arginine levels and disturb NO production.
We here hypothesize that the perturbation of the arginine/NO metabolism plays a significant role in the aetiology of cancer cachexia. Arginine/
NO metabolism is disturbed in patients with cancer. The body will try to correct this perturbation by mobilizing arginine and glutamine
from muscles. The decreased arginine levels and the disturbed NO production activate several cascades, which in turn inhibit protein
synthesis and promote proteolysis, leading to cachexia. Cachexia remains one of the most frequent and damaging opportunistic syndromes
in cancer patients. In this review we will elaborate on a new hypothesised concept and the underlying mechanisms of this syndrome.
New studies are essential to ground this hypothesis and to develop interventions to break through the pathological mechanisms
Keywords: Arginase, arginine, cancer cachexia, glutamine, immune system, iNOS, MDSC, nitric oxide, protein synthesis, proteolysis
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Published on: 31 October, 2012
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