Behavioral and electrophysiological changes induced by acetyl-L-carnitine in aged freely-moving rats

In chronically-implanted, drug-free, behaving aged Fischer rats, intracerebroventricularly (i.c.v.) and intraperitoneally (i.p.) acetyl-L-carnitine (ALCAR) injections powerfully enhanced motor behavior and head movements aimed at attention and exploratory activity. This effect was dose-dependent and associated with the abolition or substantial reduction of the incidence and duration of the spontaneous EEG generalized hypersynchronous patterns termed High Voltage Spindle (HVS), with an increase in EEG monitored theta activity. The results suggest that ALCAR may stimulate the motivational system and disrupt the hypersynchronous processes by inhibiting the GABAergic thalamic reticular neurons and/or activating the brain stem cholinergic reticular system (pedunculo pontine tegmental, PPT and laterodorsal tegmental, LDT nuclei).

Metabolic profiling by 13C-NMR spectroscopy: [1,2-13C2]glucose reveals a heterogeneous metabolism in human leukemia T cells

Metabolic profiling is defined as the simultaneous assessment of substrate fluxes within and among the different pathways of metabolite synthesis and energy production under various physiological conditions. The use of stable-isotope tracers and the analysis of the distribution of labeled carbons in various intermediates, by both mass spectrometry and NMR spectroscopy, allow the role of several metabolic processes in cell growth and death to be defined. In the present paper we describe the metabolic profiling of Jurkat cells by isotopomer analysis using (13)C-NMR spectroscopy and [1,2-(13)C(2)]glucose as the stable-isotope tracer. The isotopomer analysis of the lactate, alanine, glutamate, proline, serine, glycine, malate and ribose-5-phosphate moiety of nucleotides has allowed original integrated information regarding the pentose phosphate pathway, TCA cycle, and amino acid metabolism in proliferating human leukemia T cells to be obtained. In particular, the contribution of the glucose-6-phosphate dehydrogenase and transketolase activities to phosphoribosyl-pyrophosphate synthesis was evaluated directly by the determination of isotopomers of the [1'-(13)C], [4',5'-(13)C(2)]ribosyl moiety of nucleotides. Furthermore, the relative contribution of the glycolysis and pentose cycle to lactate production was estimated via analysis of lactate isotopomers. Interestingly, pyruvate carboxylase and pyruvate dehydrogenase flux ratios measured by glutamate isotopomers and the production of isotopomers of several metabolites showed that the metabolic processes described could not take place simultaneously in the same macrocompartments (cells). Results revealed a heterogeneous metabolism in an asynchronous cell population that may be interpreted on the basis of different metabolic phenotypes of subpopulations in relation to different cell cycle phases.

tBid induces alterations of mitochondrial fatty acid oxidation flux by malonyl-CoA-independent inhibition of carnitine palmitoyltransferase-1

Recent studies suggest a close relationship between cell metabolism and apoptosis. We have evaluated changes in lipid metabolism on permeabilized hepatocytes treated with truncated Bid (tBid) in the presence of caspase inhibitors and exogenous cytochrome c. The measurement of beta-oxidation flux by labeled palmitate demonstrates that tBid inhibits beta-oxidation, thereby resulting in the accumulation of palmitoyl-coenzyme A (CoA) and depletion of acetyl-carnitine and acylcarnitines, which is pathognomonic for inhibition of carnitine palmitoyltransferase-1 (CPT-1). We also show that tBid decreases CPT-1 activity by a mechanism independent of both malonyl-CoA, the key inhibitory molecule of CPT-1, and Bak and/or Bax, but dependent on cardiolipin decrease. Overexpression of Bcl-2, which is able to interact with CPT-1, counteracts the effects exerted by tBid on beta-oxidation. The unexpected role of tBid in the regulation of lipid beta-oxidation suggests a model in which tBid-induced metabolic decline leads to the accumulation of toxic lipid metabolites such as palmitoyl-CoA, which might become participants in the apoptotic pathway.

Could the low level of expression of the gene encoding skeletal muscle mitofusin-2 account for the metabolic inflexibility of obesity?

AIMS/HYPOTHESIS

In obesity the cellular capacity to switch from using lipid to carbohydrate and vice versa as the energy substrate, known as 'metabolic flexibility', is impaired. Mitofusin 2 (MFN2), a mitochondrial membrane protein, seems to contribute to the maintenance and operation of the mitochondrial network, and its expression is reduced in obesity. The aim of this study was to verify whether MFN2 might be implicated in the metabolic inflexibility of obesity.

MATERIALS AND METHODS

Insulin sensitivity was measured in six morbidly obese women before and 2 years after malabsorptive bariatric surgery (BMI 53.3+/-10.5 vs 30.3+/-4.0 kg/m2). Skeletal muscle MFN2, SLC2A4 (formerly known as GLUT4), COX3 (encoding cytochrome c oxidase subunit III) and CS (encoding citrate synthase) mRNA levels were measured by real-time PCR.

RESULTS

Following bilio-pancreatic surgery, significant increases in MFN2 mRNA (from 0.4+/-0.2 to 1.7+/-1.1 arbitrary units [AU], p=0.019) and SLC2A4 mRNA (0.38+/-0.12 to 0.76+/-0.24 AU, p=0.04) were observed, while increases in COX3 mRNA (from 14.2+/-6.4 to 20.2+/-12.5 AU) and CS mRNA (from 0.4+/-0.1 to 0.7+/-0.3 AU) failed to reach statistical significance. Insulin-mediated whole-body glucose uptake significantly (p<0.0001) increased from 21.2+/-4.1 to 52.8+/-5.9 micromol kg fat-free mass(-1) min(-1) and glucose oxidation rose from 11.1+/-2.1 to 37.7+/-4.7 micromol kg fat-free mass(-1) min(-1) (p<0.0001). Levels of MFN2 mRNA were strongly correlated with the absolute values for the glucose oxidation rate, both during fasting (glucose oxidation =3.55 MFN2 mRNA + 3.93; R2=0.92, p<0.0001) and during the clamp (glucose oxidation=18.8 MFN2 mRNA+34.7; R2=0.80, p<0.0001). The percentage changes in MFN2 mRNA were positively correlated with the percentage change in glucose oxidation during the clamp (glucose oxidation percent (%) change=0.3 MFN2 mRNA percent (%) change+153.2; R2=0.61, p<0.001).

CONCLUSIONS/INTERPRETATION

We propose that the significant increase in MFN2 mRNA levels may explain the increase in glucose oxidation observed in morbid obesity following bariatric surgery.

Differential expression of multiple transglutaminases in human colon: impaired keratinocyte transglutaminase expression in ulcerative colitis

BACKGROUND AND AIMS

Ulcerative colitis (UC) is characterised by refractory inflammatory ulceration and damage to the colon. The mechanisms underlying impaired healing have yet to be defined. As transglutaminase expression resulting in matrix protein cross linking is associated with increased wound healing in a rat model of colitis, we hypothesised that different types of transglutaminase might also play a role in UC.

PATIENTS AND METHODS

Endoscopic and histological indices were studied in 26 patients with UC (10 active and 16 inactive) and in 20 normal controls undergoing colonoscopy. Transglutaminase activity was evaluated in plasma (factor XIIIa) by a radioenzymatic method. Factor XIIIa, tissue and keratinocyte transglutaminase protein content, and mRNA expression in the colon were evaluated by western blot analysis and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), respectively. Colonic location of transglutaminases and their reaction products, the epsilon-(gamma-glutamyl)lysine bonds, was evaluated by immunohistochemistry using specific monoclonal antibodies.

RESULTS

Transglutaminase activity was significantly lower in the plasma of patients with active UC (4.2 (2.4) mU/ml; p<0.05 v controls) than in those with inactive UC and controls (10.6 (2.2) and 12.1 (1.7) mU/ml). As shown by western blot, protein levels of tissue transglutaminase and factor XIIIa were unchanged in active UC compared with inactive disease and controls, while the keratinocyte form was reduced in active UC. Tissue transglutaminase and factor XIIIa immunostaining was strongly present in damaged areas colocalising with isopeptide bonds. In contrast, the keratinocyte form was almost absent in active UC and localised in the upper part of the crypts in normal subjects. RT-PCR showed upregulation of tissue transglutaminase mRNA in active UC (320% compared with controls) while keratinocyte transglutaminase gene expression was downregulated in active UC.

CONCLUSIONS

The results of the present study support the concept that, in the damaged colon, transglutaminases are needed in response to chronic injury and underline the key role of these enzymes in mucosal healing.

Single-cell quantitative RT-PCR analysis of Cpt1b and Cpt2 gene expression in mouse antral oocytes and in preimplantation embryos

Fatty acids represent an important energy source for preimplantation embryos. Fatty acids oxidation is correlated with the embryo oxygen consumption which remains relatively constant up to the 8-cell stage, but suddenly increases between the 8-cell and morula stages. The degradation of fatty acids occurs in mitochondria and is catalyzed by several carnitine acyl transferases, including two carnitine palmitoyl transferases, CPT-I and CPT-II. We have carried out a study to determine the relative number of transcripts of Cpt1b and Cpt2 genes encoding for m-CPT-I and CPT-II enzymes, during mouse preimplantation development. Here we show that Cpt1b transcripts are first and temporally detected at the 2-cell stage and reappear at the morula and blastocyst stage. Cpt2 transcripts decrease following fertilization to undetectable levels and are present again later at the morula stage. These results show that transcription of both Cpt1b and Cpt2 is triggered at the morula stage, concomitantly with known increasing profiles of oxygen uptake and fatty acids oxidation. Based on the number of Cpt2 transcripts detected, we could discriminate the presence of two groups of embryos with high and low number of transcripts, from the zygote throughout preimplantation development. To further investigate if the establishment of these two groups of embryos occurs prior to fertilization, we have analyzed the relative number of transcripts of both genes in antral and ovulated MII oocytes. As for preimplantation embryos, MII oocytes show two groups of Cpt2 expression. Antral oocytes, classified according to their chromatin configuration in SN (surrounded nucleolus, in which the nucleolus is surrounded by a rim of Hoechst-positive chromatin) and NSN (not surrounded nucleolus, in which this rim is absent), show three groups with different numbers of Cpt2 transcripts. All NSN oocytes have a number of Cpt2 transcripts doubled compared to that of the group of MII oocytes with high expression. Instead, SN oocytes could be singled out into two groups with high and low numbers of Cpt2 transcripts, similar to those found in MII oocytes. The results of this study point out a correlation between the timing of fatty acids oxidation during preimplantation development and the expression of two genes encoding two enzymes involved in the oxidative pathway. Furthermore, although the biological meaning for the presence of two groups of oocytes/embryos with different levels of Cpt2 transcripts remains unclear, the data obtained suggest a possible correlation between the levels of Cpt2 expression and embryo developmental competence.

Infectious and uterus related complications during pregnancy and development of atopic and nonatopic asthma in children

BACKGROUND

It has been suggested that environmental factors early in life, particularly related to hygiene and infections, seem to be involved in the increase of asthma and allergic disease observed recently in developed countries. The possible effect of these factors also in utero have yet to be completely clarified. The aim of this study was to investigate the association between infective and uterus related complications during pregnancy, as well as related drug factors, with atopic and nonatopic asthma in children.

METHODS

This was a case-controlled study enrolling 338 children with asthma and 467 controls, who had never suffered from wheeze or asthma. Fever episodes, flu episodes, threatened abortions and related drug factors were retrospectively assessed by parental report via a standardized questionnaire. Atopy was determined by skin-prick tests to 10 prevalent allergens at the time of examination.

RESULTS

Flu episodes during pregnancy were significantly associated with development of asthma in children [adjusted odds ratio (aOR) 1.91; 95% confidence interval (95% CI) 1.1-3.2], mainly with nonatopic asthma. Fever episodes showed similar results (aOR 2.16; 95% CI 1.2-3.9), but were associated with both atopic and nonatopic asthma. The effect seems mainly due to flu and fever episodes contracted in the third trimester. Exposure to isoxsuprine was significantly associated with asthma (aOR 1.54; 95% CI 1.08-2.19) while threatened abortions were more frequent in the asthma group than in controls, although the difference was statistically significant only when such events occurred in the second trimester (aOR 2.06; 95% CI 1.07-3.94). Both threatened abortions and exposure to isoxsuprine were associated only with nonatopic asthma.

CONCLUSIONS

This study confirms that prenatal infective complications may contribute to the development of asthma in children and show a possible role for a new risk factor for asthma, that is exposure to isoxsuprine. Therefore, larger prospective studies, capable of separating atopic and nonatopic asthma, would serve to confirm these results and to explain the possible mechanism through which these factors may act.

Acetyl-l-carnitine induces a sustained potentiation of the afterhyperpolarization

Acetyl-L-carnitine is known to improve many aspects of the neural activity even if its exact role in neurotransmission is still unknown. This study investigates the effects of acetyl-L-carnitine in T segmental sensory neurons of the leech Hirudo medicinalis. These neurons are involved in some forms of neural plasticity associated with learning processes. Their physiological firing is accompanied by a large afterhyperpolarization that is mainly due to the Na+/K+ ATPase activity and partially to a Ca2+ -dependent K+ current. A clear-cut hyperpolarization and a significant increase of the afterhyperpolarization have been recorded in T neurons of leeches injected with 2 mM acetyl-L-carnitine some days before. Acute treatments of 50 microM acetyl-L-carnitine induced similar effects in T cells of naive animals. In the presence of apamin, a pharmacological blocker of Ca2+ -dependent K+ channel, acetyl-L-carnitine still enhanced the residual afterhyperpolarization, suggesting an effect of the drug on the Na+/K+ATPase. Acetyl-L-carnitine also increased the hyperpolarization induced by intracellular injection of Na+ ions. Therefore, acetyl-L-carnitine seems to be able to exert a positive sustained effect on the Na+/K+ ATPase activity in leech T sensory neurons. Moreover, in these cells, widely arborized, the afterhyperpolarization seems to play an important role in determining the action potential transmission at neuritic bifurcations. A computational model of a T cell has been previously developed considering detailed data for geometry and the modulation of the pump current. Herein, we showed that to a larger afterhyperpolarization, due to the acetyl-L-carnitine-induced effects, corresponds a decrement in the number of action potentials reaching synaptic terminals.

Metabotropic receptors as targets for drugs of potential use in the treatment of neuropathic pain

Glutamate is the major neurotransmitter in the mammalian central nervous system and plays a pivotal role in both acute and chronic pain. The actions of glutamate are mediated by two receptor families: ionotropic glutamate receptors (iGluRs), and metabotropic glutamate receptors (mGluRs). Activation of glutamate receptor can elicit both hyperalgesic and analgesic effects. Eight mGluRs subtypes (mGluR1-mGluR8) have been identified and classified into three groups. Among these, group I mGluRs (mGlu1 and -5) have been implicated in the processes of central sensitization and persistent nociception, whereas activation of group II mGluRs (mGlu2/3) is effective against neuropathic or inflammatory pain. In this review we focus on the role of mGlu2/3 in the modulation of persistent pain, and on their potential use as drug targets in pain management.

The carnitine system and body composition

Carnitine is a trimethylamine molecule that plays a unique role in cell energy metabolism. Mitochondrial betaoxidation of long-chain fatty acids, the major process by which fatty acids are oxidized, is ubiquitously dependent on carnitine. Control of mitochondrial beta-oxidation through carnitine adapts to differing requirements in different tissues. The physiological role of carnitine and its system in body composition is understood from insights into skeletal muscle metabolism, which converge into the metabolic heterogeneity of muscle fibers, and contractile properties that are correlated with phenotypes of resistance to fatigue. In skeletal muscle, the importance of the function of the carnitine system in the control and regulation of fuel partitioning not only relates to the metabolism of fatty acids and the capacity for fatty acid utilization, but also to systemic fat balance and insulin resistance. The carnitine system is shown to be determinant in insulin regulation of fat and glucose metabolic rate in skeletal muscle, this being critical in determining body composition and relevant raised levels of risk factors for cardiovascular disease, obesity, hypertension, and type 2 diabetes.

Disruption of thiol homeostasis and nitrosative stress in the cerebrospinal fluid of patients with active multiple sclerosis: evidence for a protective role of acetylcarnitine

Recent studies suggest that NO and its reactive derivative peroxynitrite are implicated in the pathogenesis of multiple sclerosis (MS). Patients dying with MS demonstrate increased astrocytic inducible nitric oxide synthase activity, as well as increased levels of iNOS mRNA. Peroxynitrite is a strong oxidant capable of damaging target tissues, particularly the brain, which is known to be endowed with poor antioxidant buffering capacity. Inducible nitric oxide synthase is upregulated in the central nervous system (CNS) of animals with experimental allergic encephalomyelitis (EAE) and in patients with MS. We have recently demonstrated in patients with active MS a significant increase of NOS activity associated with increased nitration of proteins in the cerebrospinal fluid (CSF). Acetylcarnitine is proposed as a therapeutic agent for several neurodegenerative disorders. Accordingly, in the present study, MS patients were treated for 6 months with acetylcarnitine and compared with untreated MS subjects or with patients noninflammatory neurological conditions, taken as controls. Western blot analysis showed in MS patients increased nitrosative stress associated with a significant decrease of reduced glutathione (GSH). Increased levels of oxidized glutathione (GSSG) and nitrosothiols were also observed. Interestingly, treatment of MS patients with acetylcarnitine resulted in decreased CSF levels of NO reactive metabolites and protein nitration, as well as increased content of GSH and GSH/GSSG ratio. Our data sustain the hypothesis that nitrosative stress is a major consequence of NO produced in MS-affected CNS and implicate a possible important role for acetylcarnitine in protecting brain against nitrosative stress, which may underlie the pathogenesis of MS.

Effects of propionyl-L-carnitine topical irrigation in distal ulcerative colitis: a preliminary report

BACKGROUND/AIMS

To study the tolerability of propionyl-L-carnitine administered as rectal irrigation and its efficacy in improving the clinical picture of distal ulcerative colitis.

METHODOLOGY

Ten male subjects (aged 18 to 55 years, with a body mass index ranging from 21 to 25 Kg/m2) with distal ulcerative colitis were treated with propionyl-L-carnitine enemas (6 g in 200 mL physiological solution) twice a day over 120 minutes each. All subjects had a disease activity index from 0 to 1. A clinical, laboratory, endoscopy and biopsy evaluation was performed at baseline and 14 days after treatment. Serum tumor necrosis factor-alpha and interleukin-2 concentration was measured.

RESULTS

No side effects were reported by the entire patient population and the clinical conditions remained constant throughout the study period. The disease activity index improved significantly between the beginning and the end of the study in 80% of the patients. Histologic features (mucosal erosion, distortion of crypt architecture, inflammation and lamina propria gap) significantly improved in all treated patients. Serum interleukin-2 levels did not change significantly after propionyl-L-carnitine treatment (respectively: 14.7 +/- 15.8 before vs. 9.9 +/- 13.2 pg/mL), while tumor necrosis factor-alpha levels were undetectable both before and after propionyl-L-carnitine administration.

CONCLUSIONS

The topical treatment with a new formulation containing propionyl-L-carnitine seems to be safe and effective in improving the histologic features in patients with inactive or mild ulcerative colitis, as an alternative to conventional therapy.

Long-term ethanol administration enhances age-dependent modulation of redox state in different brain regions in the rat: protection by acetyl carnitine

Chronic alcoholism is a major public health problem and causes multiorgan diseases and toxicity. Although the majority of ethanol ingested is metabolized by the liver, it has intoxicating effects in the brain. Evidence is accumulating that intermediates of oxygen reduction may be associated with the development of alcoholic disease. Several studies have shown the capacity of carnitine and its derivatives to influence ethanol metabolism. We have previously demonstrated that preadministration of L-carnitine to rats receiving ethanol significantly reduced fatty acid ethyl esters in different organs and that the carnitine/acylcarnitine system is crucial for maintaining a functional acetyl-CoA/CoA ratio under conditions in which cellular homeostasis is exposed to the deleterious effects of accumulating organic acids. Ethanol, administered to rats for 20 months, induced significant changes in the status of glutathione, primarily in the brain regions of hippocampus and cerebellum, followed by cortex and striatum, where a decrease in reduced glutathione (GSH) and the GSH/oxidized glutathione ratio was found. The same brain regions showed a significant increase in free radical-induced luminescence and hydroxynonenal (HNE), which were associated with decreased GSH reductase activity. Long-term supplementation with acetyl carnitine significantly reduced GSH depletion, particularly in the brain regions of hippocampus, an effect associated with decreased luminescence and HNE formation. In addition, acetyl carnitine treatment increased GSH reductase and arginase activities. Our results indicate that decreased GSH reductase activities associated with thiol depletion are important factors sustaining a pathogenic role in alcohol-related pathologies. Administration of acetyl carnitine greatly reduces these metabolic abnormalities. This evidence supports the pharmacological potential of acetyl carnitine in the management of alcoholic disturbances.

Fever episodes in early life and the development of atopy in children with asthma

The hygiene hypothesis proposes that declining exposure to infections may contribute to the allergy and asthma "epidemic", but studies to identify the infections involved have so far provided conflicting data. An alternative approach could be based on an attempt to identify the mechanisms common to several different infections, which may exert an atopy "protective" effect. One of these mechanisms may be fever, which is frequently associated with infections and may stimulate the synthesis of interferon-gamma. The aim of this study was to test whether the frequency of fever episodes in the first years of life are related to the development of atopy. Asthmatic (cases, n=317) and nonasthmatic children (controls, n=304) attending the outpatients' allergy clinic were enrolled. The number of fever episodes in the first 2 yrs of life was retrospectively assessed by parental report via a questionnaire completed by interview. Atopy was determined by skin-prick tests to 10 prevalent inhalant allergens at the time of examination. Fever episodes in the first or in the second year of life were significantly more frequent among children with asthma. However, this difference was totally accounted for by a subgroup of children who started wheezing in the first 12 months of life. A significant inverse association between fever episodes in the first 12 months of life and atopy was found among cases, but not in controls. The association persisted after adjusting for age, sex, daycare attendance and family history of atopic disease and this was totally accounted for by asthmatic children who started wheezing after the first 12 months of life. No significant association was found between fever episodes in the second year of life and atopy for cases and controls. The data presented here suggests that fever episodes early in life may affect the natural history of asthma by preventing the development of atopy and highlights the need to monitor fever episodes of any kind in longitudinal studies aimed at investigating the hygiene hypothesis prospectively.

L-Acetylcarnitine induces analgesia by selectively up-regulating mGlu2 metabotropic glutamate receptors

L-Acetylcarnitine (LAC, 100 mg/kg, s.c.), a drug commonly used for the treatment of painful neuropathies, substantially reduced mechanical allodynia in rats subjected to monolateral chronic constriction injury (CCI) of the sciatic nerve and also attenuated acute thermal pain in intact rats. In both cases, induction of analgesia required repeated injections of LAC, suggesting that the drug induces plastic changes within the nociceptive pathway. In both CCI- and sham-operated rats, a 24-day treatment with LAC increased the expression of metabotropic glutamate (mGlu) receptors 2 and 3 in the lumbar segment of the spinal cord, without changing the expression of mGlu1a or -5 receptors. A similar up-regulation of mGlu2/3 receptors was detected in the dorsal horns and dorsal root ganglia of intact rats treated with LAC for 5-7 days, a time sufficient for the induction of thermal analgesia. Immunohistochemical analysis showed that LAC treatment enhanced mGlu2/3 immunoreactivity in the inner part of lamina II and in laminae III and IV of the spinal cord. An increased mGlu2/3 receptor expression was also observed in the cerebral cortex but not in the hippocampus or cerebellum of LAC-treated animals. Reverse transcription-polymerase chain reaction combined with Northern blot analysis showed that repeated LAC injections selectively induced mGlu2 mRNA in the dorsal horns and cerebral cortex (but not in the hippocampus). mGlu3 mRNA levels did not change in any brain region of LAC-treated animals. To examine whether the selective up-regulation of mGlu2 receptors had any role in LAC-induced analgesia, we have used the novel compound LY 341495, which is a potent and systemically active mGlu2/3 receptor antagonist. LAC-induced analgesia was largely reduced 45 to 75 min after a single injection of LY 341495 (1 mg/kg, i.p.) in both CCI rats tested for mechanical allodynia and intact rats tested for thermal pain. We conclude that LAC produces analgesia against chronic pain produced not only by peripheral nerve injury but also by acute pain in intact animals and that LAC-induced analgesia is associated with and causally related to a selective up-regulation of mGlu2 receptors. This offers the first example of a selective induction of mGlu2 receptors and discloses a novel mechanism for drug-induced analgesia.

Long-term ethanol administration enhances age-dependent modulation of redox state in brain and peripheral organs of rat: protection by acetyl carnitine

Evidence is accumulating that intermediates of oxygen reduction may be associated with the development of alcoholic disease. Free radical-induced perturbation of the oxidant/antioxidant balance in the cell is widely recognized as the main causative factor of age-related disorders. In the present study we investigated the effects of 20 months of ethanol consumption on the antioxidant defense system in different rat organs compared with normal aging in the absence and presence of treatment with L-acetyl carnitine. We demonstrate that aged rats underwent significant perturbation of the antioxidant defense system, as indicated by depletion of reduced glutathione (GSH) content, increased oxidized GSH, free radical-induced luminescence associated with increased hydroxynonenal content and decreased GSH reductase activity. These modifications, observed particularly in brain and liver compared with other organs, were enhanced by long-term alcohol exposure and, interestingly, were significantly reduced with acetyl carnitine supplements. Our results indicate that decreased GSH reductase activity and thiol depletion are important factors in effecting a pathogenic role for oxidative stress in aging and in all situations in which age-correlated and oxidant-induced changes occur, such as in alcoholism. Administration of acetyl carnitine greatly reduces these metabolic abnormalities. Our findings support its pharmacological potential in the management of alcoholic disturbances.

Synthesis and release of neurotoxic kynurenine metabolites by human monocyte-derived macrophages

We studied the regulation of the kynurenine pathway of tryptophan metabolism in human monocyte-derived macrophages (MDM) with the aim of evaluating macrophage involvement in inflammatory neurological disorders. Cultured MDM metabolized tryptophan and released kynurenine metabolites, including the excitotoxin quinolinic acid (QUIN). Lipopolysaccharides (LPS) or the pro-inflammatory cytokines INFgamma and TNFalpha increased, while IL 4 or IL 10 inhibited the rate of tryptophan metabolism and the release of QUIN. The incubation media of INFgamma-exposed MDM caused neuronal death in primary cultures of mixed cortical cells. Glutamate receptor antagonists or poly(ADP-ribose) polymerase inhibitors significantly reduced this death, thus suggesting new possibilities for the treatment of neuronal damage in neuroinflammatory disorders.

[L-acetylcarnitine treatment on fragile X patients hyperactive behaviour]

Hyperactivity is a significant problem for almost all young males affected by fragile X syndrome (FXS), the most common inherited disease causing mental retardation. Therapeutical approaches are actually based on Central Nervous System (CNS) stimulants lacking a well defined rationale and efficacy while they further decrease the patient's limited attention span. A pilot study on 17 fragile X male treated with L-acetylcarnitine (LAC) over one year, showed a significant reduction of their hyperactivity behaviour tested by the Conners Abbreviated Parent-Teacher Questionnaire. LAC use in FXS patients derives from the hypothesis that the biochemical and physiological properties this substance has may preserve brain activity. LAC is a small, hydrosoluble molecule that easily diffuses in the extracellular space and enters any cell in the nervous system through specific transporters. Different cerebral areas use this molecule differently to metabolize glucose and lipids to provide for ATP and neurotrasmitters synthesis. The acetyl group LAC carriers represents a key metabolic signaling element possibly mediating its effect in the CNS. The exogenous administration of LAC may affect brain activity in FXS by: I) modulation of fuel partitioning for energy production, which at the mithocondrial level is associated with the Kreb's cycle metabolic role in neurotransmitter synthesis; II) remodelling of lipid membrane in terms of LAC actively determining the production of polyunsaturated fatty acids; III) preferential effect on the attention component of the cholinergic system which relies on its peculiar modality of communication in the CNS. Based on the above premises an explorative, double-blind, placebo controlled, multicenter study is ongoing. A total population of 160 children from nine European centers will be enrolled. The objective of this study is to determine the effect of LAC on the hyperactive behaviour of FXS children as evaluated by the administration of the Conners Abbreviated Parent Questionnaire.