Th 1 cytokine production by peripheral blood mononuclear cells in X-linked adrenoleukodystrophy.

Cerebral adrenoleukodystrophy (ALD) and adrenomyeloneuropathy (AMN) are the two most frequent clinical phenotypes of the same genetic defect leading to the accumulation of very long chain fatty acids (VLCFA). Previous studies have suggested that inflammatory cytokines may play a role in the cerebral demyelination and in phenotype expression of the disease. We analyzed cytokine production by stimulated peripheral blood mononuclear cells (PBMC) from 17 patients (four asymptomatic subjects, eight AMN and five ALD). Our results show that lipopolysaccarides (LPS) stimulated PBMC from both symptomatic and asymptomatic patients have an increased production of IL-12 and TNFalpha compared to controls, while after phitoemoagglutinin (PHA) stimulation we observed a decreased production of IL-6 and IL-10. These data indicate that, following an immunological stimulus, PBMC from patients have an increased production of cytokines typical of a Th1 cell response which is able to promote the inflammatory process. This characteristic profile of cytokine production could be related to the biochemical defect and could have a role in central nervous system (CNS) pathogenesis.

Diet, lipids and brain development.

Brain development is a sequential anatomical process characterised by specific well-defined stages of growth and maturation. One of the fundamental and necessary events in the normal development of the central nervous system in vertebrates is the formation of a myelin sheath. It is becoming more evident that this process is influenced by dietary lipids. A number of findings have indicated that the administration of a diet deficient in essential fatty acids during development causes hypomyelination in the rat brain. Our studies have shown that lipids can also play a role in accelerating myelinogenesis in the brain of rats whose mothers had been fed, during pregnancy and lactation, a lipid fraction extracted from yeast grown on n-alkanes. Further studies have shown that accelerated myelinogenesis is connected to a precocious appearance of behavioural reflexes. Thus, the use of particular lipids in human nutrition must be carefully screened for possible effects on brain development.

Susceptibility to oxidation of plasma low-density lipoprotein in X-linked adrenoleukodystrophy: effects of simvastatin treatment.

This paper shows for the first time the higher oxidizability of low-density lipoprotein (LDL) in plasma from adrenoleukodystrophy (ALD) patients compared to that of control subjects. LDL oxidation susceptibility was assessed by conjugate diene formation, hydroperoxide and lipoperoxide formation, and electrophoretic mobility. Simvastatin therapy, an HMG-CoA reductase inhibitor, seems to be a protective pharmacological agent against the higher oxidizability of LDL in plasma from ALD patients.

The Myelinogenesis Process in Undernourished Rats Rehabilitated with Different Dietary Lipids.

Our previous studies have indicated that pups born from mothers fed lipids obtained from yeast (Candida lypolitica) grown on n-alkanes during pregnancy and lactation show an acceleration of myelinogenesis. In the present work we carried out experiments using an undernutrition model to establish if such microbial lipids can also play a role in accelerating the myelin process in hypomyelinated rats. This model was produced by restricting maternal dietary intake during the last 4 days of pregnancy and the lactating period. Diet-restricted dams were divided into 3 groups when pups were 14 days old. The first group was switched to ad libitum diet containing 9% margarine and 1% corn oil, the second to ad libitum feeding diet containing 10% of microbial lipids and the third to ad libitum feeding standard diet containing 3% of lipids. The offspring were sacrificed at differing days of nutritional rehabilitation. The recovery of the body and brain weight was slower in rats fed 3% of lipids than animals maintained on 10% of lipids. The test group showed an earlier increase both in the relative levels of proteolipid protein (PLP) and myelin oligodendrocyte glycoprotein (MOG) mRNAs and in the 2'-3'-cyclic nucleotide 3' phosphohydrolase (CNPase) activity compared with the other two groups. These results indicate that the reversal of myelin delay would seem to be accelerated in the group fed microbial lipids.

[Adrenoleukodystrophy: genetics, phenotypes, pathogenesis, and treatment]. / Adrenoleucodistrofia: genetica, fenotipi, patogenesi e trattamento.

Adrenoleukodystrophy is a genetically determined disorder inherited as an X-linked recessive trait due to the defective peroxisomal oxydation of very long chain fatty acids (VLCFA). It is hallmarked by demyelination of the central nervous system and adrenal insufficiency. Even though the studies concerning the molecular basis of the disease are in progress, the role of VLCFA in the demyelination is still unclear. In this paper we report the most recent knowledges about genetics, pathogenesis and treatment of this disorder. 117 cases have been recognized in Italy in the period 1985-1997, but many cases could be missing due to the heterogeneus clinical manifestations that vary from mild to very severe forms. To control the devastating course of this disease two therapeutic approaches are under evaluation: bone marrow transplantation and dietary treatment based on a mixture of glyceroyl trioleate and glyceroyl trierucate. Nevertheless this dietary treatment provides normalization of plasma VLCFA, no significant modification of the natural course of the disease has been demonstrated. For what concerns bone marrow transplantation, in recent years a more accurate selection of patients and donors has been giving favourable results, but some strict criteria should be respected.

X-linked adrenoleukodystrophy: first report of the Italian Study Group.

In this paper we report Italian data on X-linked adrenoleukodystrophy (ALD) collected from 1985 to 1997. This disease appears to be the most common of the peroxisomal disorders and is associated with a functional defect of the peroxisomal very long chain fatty acid (VLCFA) oxidation. In Italy 117 cases have been recognized, but many cases may be unrecognized due to the heterogeneous clinical manifestations that vary from mild to very severe forms. To control the devastating course of this disease two therapeutic approaches are under evaluation: bone marrow transplantation (BMT) and dietary treatment based on a mixture of glyceroyl trioleate (GTO) and glyceroyl trierucate (GTE). Our experience of 68 subjects submitted to dietary treatment shows that almost all patients with signs of cerebral involvement at the beginning of treatment worsened or died, patients with the milder form, adrenomyeloneuropathy (AMN), remained stable, while 4 of the 15 presymptomatic subjects developed neurological signs of the disease. In recent years a more accurate selection of patients and donors for BMT has given favourable results, but some strict criteria should be respected.

Effects of exogenous hexacosanoic acid on biochemical myelin composition in weaning and post-weaning rats.

X-linked Adrenoleukodistrophy (ALD) is characterized by an increase of very long chain fatty acids (VLCFA) in particular of hexacosanoic acid (HA), in tissues and fluids. The biochemical abnormality is due to the dysfunction of peroxisomal degradation of VLCFA. To-date it is unclear if the demyelination which characterizes this disease is the direct consequence of HA accumulation. In order to investigate whether the large amounts of exogenous HA could affect myelin synthesis, 500 micrograms of this fatty acid dissolved in peanut oil were administered daily and by gavage to newborn rats. Since myelin is actively synthesized during early neonatal life and it can be altered by environmental factors including diet, we analyzed lipid and protein composition of myelin after 20, 30 and 60 days of HA administration. Our results show that exogenous HA is incorporated in myelin where it determines biochemical alterations in normal rats having a functioning peroxisomal system. Even though the differences between controls and treated rats are slight, we observed in test rats, a decrease of 2'3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) activity and of myelin basic protein (MBP) content at any time studied. The decrease of glycolipids (GL) was present only after 20 days of treatment. Since these parameters are related to myelin development, our data lead us to think that the myelin of the treated animals is less mature than that of controls.

Influences of hypothyroidism on lipid composition and inositol lipid-linked receptors responsiveness and protein kinase C (PKC) activity in the cerebral cortex of Lewis rats.

The influence of hypothyroidism (HO) induced by treatment with propylthiouracil on lipid composition, receptor responsiveness of M1-muscarinic receptors (M1AChRs) and metabotropic glutamate receptors (mGluRs) as well as on protein kinase C (PKC) activity was investigated in the cerebral cortex of Lewis rats. HO did not influence the lipid composition. There was a significant 2-fold increase of efficacy and 6-fold decrease of potency of carbachol-induced inositol phosphate (IP) accumulation in HO, with respect to control rats. The efficacy of trans-(1S,3R)-1-amino-1,3-cyclopentanedicarboxylic acid (ACPD)-induced IP accumulation was also higher in HO (by 50%), without differences in EC50 values. The activities of soluble calcium-dependent and calcium-independent PKC were higher in HO than in control rats (both roughly 30%); membrane-associated PKCs were not modified. The data indicate that HO induces an increased responsiveness of M1AChRs and mGluRs and a rise in the soluble PKC activity that could be available and ready for translocation.

Accelerated myelinogenesis induced by dietary lipids in rats.

Our previous work has shown an early development of behavioral reflexes in the offspring of rats maintained on diets containing a lipid fraction extracted from yeast (Candida lypolitica) grown on n-alkanes during pregnancy and throughout lactation. Since some of these changes could be linked to an early myelination, in this study we investigated myelin maturation in the rat brain by immunohistochemistry. At 7 days the test groups showed considerable immunopositivity to myelin basic protein and proteolipid protein at a more rostral level, such as the corpus callosum where immunopositivity is usually detected later in brain development. At 7 days in controls, staining fibers were detected only in the lower brainstem and in the cerebellum. Immunopositivity in the same regions was more intense in the test groups. Some litters were fostered at birth to produce 2 groups of animals: pups whose mothers were fed a control diet prenatally and the test diet postnatally, and vice versa. Positive fibers are already present at 7 days in the telencephalon area in both groups. These data indicate that dietary lipids can interfere with brain development by accelerating myelinogenesis.