Potential Role of L-Carnitine in Autism Spectrum Disorder.

L-carnitine plays an important role in the functioning of the central nervous system, and especially in the mitochondrial metabolism of fatty acids. Altered carnitine metabolism, abnormal fatty acid metabolism in patients with autism spectrum disorder (ASD) has been documented. ASD is a complex heterogeneous neurodevelopmental condition that is usually diagnosed in early childhood. Patients with ASD require careful classification as this heterogeneous clinical category may include patients with an intellectual disability or high functioning, epilepsy, language impairments, or associated Mendelian genetic conditions. L-carnitine participates in the long-chain oxidation of fatty acids in the brain, stimulates acetylcholine synthesis (donor of the acyl groups), stimulates expression of growth-associated protein-43, prevents cell apoptosis and neuron damage and stimulates neurotransmission. Determination of L-carnitine in serum/plasma and analysis of acylcarnitines in a dried blood spot may be useful in ASD diagnosis and treatment. Changes in the acylcarnitine profiles may indicate potential mitochondrial dysfunctions and abnormal fatty acid metabolism in ASD children. L-carnitine deficiency or deregulation of L-carnitine metabolism in ASD is accompanied by disturbances of other metabolic pathways, e.g., Krebs cycle, the activity of respiratory chain complexes, indicative of mitochondrial dysfunction. Supplementation of L-carnitine may be beneficial to alleviate behavioral and cognitive symptoms in ASD patients.

Preventive Role of L-Carnitine and Balanced Diet in Alzheimer's Disease.

The prevention or alleviation of neurodegenerative diseases, including Alzheimer's disease (AD), is a challenge for contemporary health services. The aim of this study was to review the literature on the prevention or alleviation of AD by introducing an appropriate carnitine-rich diet, dietary carnitine supplements and the MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) diet, which contains elements of the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet. L-carnitine (LC) plays a crucial role in the energetic metabolism of the cell. A properly balanced diet contains a substantial amount of LC as well as essential amino acids and microelements taking part in endogenous carnitine synthesis. In healthy people, carnitine biosynthesis is sufficient to prevent the symptoms of carnitine deficiency. In persons with dysfunction of mitochondria, e.g., with AD connected with extensive degeneration of the brain structures, there are often serious disturbances in the functioning of the whole organism. The Mediterranean diet is characterized by a high consumption of fruits and vegetables, cereals, nuts, olive oil, and seeds as the major source of fats, moderate consumption of fish and poultry, low to moderate consumption of dairy products and alcohol, and low intake of red and processed meat. The introduction of foodstuffs rich in carnitine and the MIND diet or carnitine supplementation of the AD patients may improve their functioning in everyday life.

The role of carnitine in the perinatal period.

Carnitine (2-hydroxy-4-trimethylammonium butyrate, vitamin BT) is a small hydrophilic molecule derived from protein-bound lysine, not degraded in the body but excreted via urine, bile and breast milk. Carnitine stimulates the catabolism of long-chain fatty acids (FAs), by transporting them to mitochondria for oxidation, and the intracellular decomposition of branched-chain ketoacids. It also helps to excrete toxic exogenous and nontoxic endogenous organic acids via urine. It further participates in the production of pulmonary surfactant, inhibits free radicals production and demonstrates other antioxidant properties. After delivery, infants dramatically increase energy demands for movement, growth, differentiation and maintenance of the body temperature that strongly depend on FAs oxidation which is facilitated by carnitine. At early stages of life, carnitine biosynthesis is less efficient than in adults and immature infants have less carnitine tissue reserves than term infants. Carnitine supplementation is recommended in newborns with aciduria, childhood epilepsy associated with valproate-induced hepatotoxicity, in kidney-associated syndromes, and premature infants receiving total parenteral nutrition. Concentrations of carnitine and acylcarnitines in neonatal blood have been postulated a useful tool for the diagnosis of type 1 diabetes, as well as the detection and monitoring of many inherited and acquired metabolic disorders. Taking into account the complex metabolic role of cellular FAs transporters, further studies are needed on indications and contraindications for carnitine supplementation in different clinical settings during early developmental period.

Plasma carnitine concentrations after chronic alcohol intoxication.

BACKGROUND: Carnitine transports fatty acids from the cytoplasm to the mitochondrial matrix, where the fatty acids are oxidized. Chronic alcohol consumption reduces the concentration of carnitine and interferes with oxidative processes occurring in the cell. AIM: The assessment of carnitine concentrations in plasma of chronically intoxicated alcohol dependent persons in a 49-day abstinence period. MATERIAL/METHODS: The study included 31 patients (5 women and 27 men) aged from 26 to 60 years (44.6 ± 8.9) and 32 healthy subjects (15 women and 17 men) aged 22-60 years (39.8 ± 9.4). The patients' alcohol dependence ranged from 2 to 30 years (13.6 ± 7.5). Examined subjects consumed 75-700 g of ethanol/day (226.9 ± 151.5). Plasma concentrations of free and total carnitine were measured three times: at the first (T0), 30th (T30) and 49th (T49) day of hospital detoxification. Free (FC) and total (TC) carnitine were determined by the spectrophotometric method. Plasma acylcarnitine (AC) concentration was calculated from the difference between TC and FC; then the AC/FC ratio was calculated. To determine statistically significant differences for related variables, Student's t-test was used. RESULTS: At T0, alcoholics had significantly lower concentration of FC and TC (p < 0.05) in plasma, as compared to the control group. In comparison to controls, at T30, plasma TC and FC (p < 0.01) as well as AC (p < 0.001) were reduced. The lowest concentration of TC, FC and AC (p < 0.001)was found at T49. The ratio of AC/FC at T0 had a tendency to be higher in alcoholics than in the control group (p = 0.05), whereas at T49 it was significantly lower in alcoholics as compared to the control subjects (p < 0.05). CONCLUSIONS: Chronic alcohol intoxication causes a plasma deficiency of carnitine. Forty-nine days of abstinence showed a significant decrease in the concentration of TC, FC and AC. Further research is necessary to clarify whether a low level of plasma carnitine after chronic alcohol intoxication is caused by the uptake of blood carnitine by tissues such as liver or muscles. In alcoholics the supplementation of carnitine is recommended in the case of a low level of plasma carnitine.