Levocarnitine administration in elderly subjects with rapid muscle fatigue: effect on body composition, lipid profile and fatigue

Risk assessment for carnitine

Carnitine is a conditionally essential amino acid-like compound involved in the transport of long-chain fatty acids into the mitochondria during the beta-oxidation process. Carnitine has become an increasingly popular ingredient in dietary supplements, especially weight loss and some sports nutrition products. A number of clinical trials have been conducted examining the effect of carnitine supplementation on weight loss and energy balance. Regarding safety, systematic evaluation of the research designs and data do not provide a basis for risk assessment and the usual safe upper level of intake (UL) derived from it unless the newer methods described as the observed safe level (OSL) or highest observed intake (HOI) are utilized. The OSL risk assessment method indicates that the evidence of safety is strong at intakes up to 2000mg/day l-carnitine equivalents for chronic supplementation, and this level is identified as the OSL. Although much higher levels have been tested without adverse effects and may be safe, the data for intakes above 2000mg/day are not sufficient for a confident conclusion of long-term safety.

Efficacy of l-carnitine administration on fatigue, nutritional status, oxidative stress, and related quality of life in 12 advanced cancer patients undergoing anticancer therapy

OBJECTIVE

Fatigue is a multidimensional symptom that is described in terms of perceived energy, mental capacity, and psychological status: it can impair daily functioning and lead to negative effects on quality of life. It is one of the most common side effects of chemotherapy and radiotherapy. In recent studies, l-carnitine (LC) supplementation has been demonstrated to be able to improve fatigue symptoms in patients with cancer.

METHODS

In the present study we tested the efficacy and safety of LC supplementation in a population of patients who had advanced cancer and developed fatigue, high blood levels of reactive oxygen species, or both. As outcome measures we evaluated fatigue and quality of life in relation to oxidative stress, nutritional status, and laboratory variables, mainly levels of reactive oxygen species, glutathione peroxidase, and proinflammatory cytokines. From March to July 2004, 12 patients who had advanced tumors (50% at stage IV) at different sites were enrolled (male-to-female ratio 2:10, mean age 60 y, range 42-73). Patients were only slightly anemic (hemoglobin 10.9 g/dL) and hemoglobin levels did not change after treatment. LC was administered orally at 6 g/d for 4 wk. All patients underwent antineoplastic treatment during LC supplementation.

RESULTS

Fatigue, as measured by the Multidimensional Fatigue Symptom Inventory-Short Form, decreased significantly, particularly for the General and Physical scales, and for quality of life in each subscale of quality of life in relation to oxidative stress. Nutritional variables (lean body mass and appetite) increased significantly after LC supplementation. Levels of reactive oxygen species decreased and glutathione peroxidase increased but not significantly. Proinflammatory cytokines did not change significantly.

CONCLUSION

Improvement of symptoms with respect to fatigue and quality of life in relation to oxidative stress may be explained mainly by an increase in lean body mass, which may be considered the most important nutritional or functional parameter in assessing the cachectic state of patients. In this view, fatigue with related symptoms can well be considered an important constituent of cancer-related anorexia cachexia syndrome.

Decrease of serum carnitine levels in patients with or without gastrointestinal cancer cachexia

AIM: To evaluate the levels of serum carnitine in patients with cancer in digestive organs and to compare them with other cancers in order to provide new insights into the mechanisms of cachexia.

METHODS: Fifty-five cachectic patients with or without gastrointestinal cancer were enrolled in the present study. They underwent routine laboratory investigations, including examination of the levels of various forms of carnitine present in serum (i.e., long-chain acylcarnitine, short-chain acylcarnitine, free carnitine, and total carnitine). These values were compared with those found in 60 cancer patients in good nutritional status as well as with those of 30 healthy control subjects.

RESULTS: When the cachectic patients with gastro-intestinal cancer were compared with the cachectic patients without gastrointestinal cancer, the difference was -6.8 μmol/L in free carnitine (P < 0.005), 0.04 μmol/L in long chain acylcarnitine (P < 0.05), 8.7 μmol/L in total carnitine (P < 0.001). In the cachectic patients with or without gastrointestinal cancer, the difference was 12.2 μmol/L in free carnitine (P < 0.001), 4.60 μmol/L in short chain acylcarnitine (P < 0.001), and 0.60 μmol /L in long-chain acylcarnitine (P < 0.005) and 17.4 μmol/L in total carnitine (P < 0.001). In the cachectic patients with gastrointestinal cancer and the healthy control subjects, the difference was 15.5 μmol/L in free carnitine (P < 0.001), 5.2 μmol /L in short-chain acylcarnitine (P < 0.001), 1.0 μmol/L in long chain acylcarnitine (P < 0.001), and 21.8 μmol/L in total carnitine (P < 0.001).

CONCLUSION: Low serum levels of carnitine in terminal neoplastic patients are decreased greatly due to the decreased dietary intake and impaired endogenous synthesis of this substance. These low serum carnitine levels also contribute to the progression of cachexia in cancer patients.

Antimyopathic effects of carnitine and nicotine

PURPOSE OF REVIEW

The clinical course of most chronic diseases is associated with declined energy intake and nutrient-resistant progressive myopathy, characterized by accelerated proteolysis and impaired function. This anorexia/cachexia syndrome leads to deterioration of quality of life, and increased morbidity and mortality. The clinical efficacy of currently available therapeutic strategies is limited and more effective treatments are needed.

RECENT FINDINGS

Chronic systemic inflammation, triggered and sustained by cytokines, and increased oxidative stress contribute to the pathogenesis of the anorexia/cachexia syndrome. Carnitine and nicotine have recently been tested as immunomodulating and antioxidant agents. In particular, carnitine supplementation has been shown to reduce chronic inflammation and oxidative stress in hemodialysis patients and, in cancer patients, yielding to reduced fatigue and improved outcome. Nicotine is able to induce the anti-inflammatory activity of the vagus nerve. In animal models of sepsis and cancer, the nicotine-induced supplementation resulted in better protection of nutritional status and improved survival.

SUMMARY

In the continuous effort to develop more efficacious strategies against the anorexia/cachexia syndrome, carnitine and nicotine may represent a further therapeutic tool. More clinical studies are needed, however, before their use can be routinely suggested.

Serum carnitine levels in patients with tumoral cachexia

BACKGROUND

Cachexia is a serious complication of many cancers that is common in cancer and AIDS patients. However, the key factors and mechanisms involved in the development of cachexia are not yet understood. There is little data currently available regarding carnitine metabolism in patients with neoplasm and cachexia.

METHODS

Forty-six neoplastic patients with different localizations of their primary disease gave signed, informed consent before enrolling in the present study. They underwent routine laboratory investigation, including examination of the levels of the various forms of carnitine present in serum (i.e., long-chain acylcarnitine, short-chain acylcarnitine, soluble acid acylcarnitine, free carnitine, and total carnitine). These values were compared with those found in 30 cancer patients in good nutritional status as well as with those of 30 healthy control subjects.

RESULTS

In the comparison of serum plasma carnitine of cachectic patients versus controls, the difference in free carnitine was - 8.20 micromol/L (p=0.000); the difference in short-chain acylcarnitine - 2.60 micromol/L (p=0.029); the difference in soluble acid carnitine - 10.80 micromol/L (p=0.000); the difference in long-chain acylcarnitine - 0.40 micromol/L (p=0.036); and the difference in total carnitine -11.20 micromol/L (p=0.000). In the comparison of serum plasma carnitine of cachectic versus neoplastic patients in good nutritional status, the difference in free carnitine was -5.80 micromol/L (p=0.006); the difference in soluble acid carnitine - 7.20 micromol/L (p=0.000); and the difference in total carnitine - 7.50 micromol/L (p=0.000).

CONCLUSION

Our study showed that, in the multifactorial pathogenesis of cachexia, the low serum levels of carnitine in terminal neoplastic patients, which are due to a decreased dietary intake as well as to an impaired endogenous synthesis of this substance, could play an important role. These low serum carnitine levels may also contribute to the development of cachexia in cancer patients.