Cachexia And Cancer
Researchers previously believed that cancer increased metabolic demand (stolen protein), produced toxins, and suppressed appetite, resulting in malnutrition. New research, however, shows that although cancer may raise resting metabolic rate, improved nutrition does not alleviate the symptoms of anorexia, chronic nausea, early satiety, and changes in taste that make even favorite foods unpalatable to some cancer patients. The view of clinicians is that bodily wasting is the result of a combined action of tumor products and host immune factors—cytokines, in particular--that lead to poor appetite, muscle wasting, and an altered metabolism. The cytokines interleukin-1 (IL-1), interleukin-6 (IL-6), interferon-gamma, tumor necrosis factor-alpha (TNF-α), and brain-derived neurotrophic factor appear to increase and play a role in the progression of cachexia in cancer, as well as in other diseases associated with bodily wasting.
Other metabolic alterations associated with the syndrome are hyperglyceridemia, lipolysis, and accelerated protein turnover, all leading to a loss of fat mass and body protein. The dysregulation of metabolic processes produces a negative energy balance.
Clinicians are currently treating cancer-related catabolic wasting with a variety of interventions, including nutritional supplementation, administration of cytokine inhibitors, steroids, hormones, cannabinoids, and thalidomide. Gemcitabine, a chemotherapeutic drug, has shown clinical benefits in treating cachexia. Newer nutritional interventions with megestrol acetate derivatives, gamma-receptor agonists, amino acid manipulations, myostatin inhibitors, and uncoupling protein modifiers is currently being explored. Further research must be done to investigate gender differences in relation to pathophysiology and therapy.
There is some evidence that the drug hydrazine sulfate may help cancer patients gain weight and improve the cachectic state. The drug is by prescription and should be given by a complementary physician familiar with its use, as it can be toxic. The dose is usually 60 mg daily. Narcotic painkillers or benzodiazepine anxiety-reducing agents cannot be given concomitantly.
Cachexia And HIV
Bodily wasting is a common manifestation of HIV, occurring at any state of infection and indicative of disease progression. Malnutrition, a result of appetite loss, is commonly due to nausea and vomiting. Weakness and diarrhea are often present as well. Persons with HIV may also experience malabsorption of nutrients due to enteric infections associated with the disease, even if they consume sufficient calories.
The effects of malnutrition are thought to contribute to increased immune suppression including a reduction in T-lymphocyte helper and suppressor cells, altered phagocytic functions, and decreased killer-cell activity, leading to opportunistic infections and cancers. Pro-inflammatory cytokines IL-1, IL-6, and TNF have been cited in many studies as potential causes of wasting. Most people with advanced HIV and AIDS have some degree of wasting.
To reverse weight loss, appetite stimulants, anabolic agents (such as growth hormone or testosterone), cytokine inhibitors, and hormones are often prescribed. Megestrol acetate and dronabinol (which contains the active ingredient in marijuana) are approved for the treatment of wasting. Thalidomide, which aids in the healing of aphthous ulcers of the mouth and esophagus, is now available.