Very long chain fatty acids in X-linked adrenoleukodystrophy brain after treatment with Lorenzo's oil

Brassicaceae Mustards: Phytochemical Constituents, Pharmacological Effects, and Mechanisms of Action against Human Disease

The Brassicaceae genus consists of many economically important mustards of value for food and medicinal purposes, namely Asian mustard (Brassica juncea), ball mustard (Neslia paniculata), black mustard (B. nigra), garlic mustard (Alliaria petiolata), hedge mustard (Sisymbrium officinale), Asian hedge mustard (S. orientale), oilseed rape (B. napus), rapeseed (B. rapa), treacle mustard (Erysimum repandum), smooth mustard (S. erysimoides), white ball mustard (Calepina irregularis), white mustard (Sinapis alba), and Canola. Some of these are commercially cultivated as oilseeds to meet the global demand for a healthy plant-derived oil, high in polyunsaturated fats, i.e., B. napus and B. juncea. Other species are foraged from the wild where they grow on roadsides and as a weed of arable land, i.e., E. repandum and S. erysimoides, and harvested for medicinal uses. These plants contain a diverse range of bioactive natural products including sulfur-containing glucosinolates and other potentially valuable compounds, namely omega-3-fatty acids, terpenoids, phenylpropanoids, flavonoids, tannins, S-methyl cysteine sulfoxide, and trace-elements. Various parts of these plants and many of the molecules that are produced throughout the plant have been used in traditional medicines and more recently in the mainstream pharmaceutical and food industries. This study relates the uses of mustards in traditional medicines with their bioactive molecules and possible mechanisms of action and provides an overview of the current knowledge of Brassicaceae oilseeds and mustards, their phytochemicals, and their biological activities.

Adult-onset adrenoleukodystrophy presenting with status epilepticus and psychosis

Adrenoleukodystrophy (ALD) is an X linked recessive genetic disorder caused by an abnormality in the ABCD1 gene on the X chromosome, that affects 1 in 20 000 people. In X linked adrenoleukodystrophy (X-ALD), a defect in lignoceroyl-coenzyme A ligase causes pathognomonic tissue accumulation of very long chain fatty acids (VLCFA) in the adrenal cortex and nervous system. The phenotypic variability ranges from cerebral inflammatory demyelination of childhood onset, leading to death within 5 years, to adults remaining presymptomatic through more than five decades. Our case is that of a man who was previously diagnosed with bipolar affective disorder presented with dystonic posturing. During transit, he had an episode of generalised convulsive status epilepticus. He presented with spasticity and exaggerated reflexes. Three important signs of adrenal insufficiency were observed: hypotension, hyperpigmentation and comatose state. The diagnosis of X-ALD should be considered in young men presenting with gradually progressive unexplained cognitive and behavioural problems, a strong family history, adrenal insufficiency, bilateral upper motor signs with absent ankle reflexes.

Association between mustard oil consumption and BMI in India

OBJECTIVE

This study examined the association between predominant vegetable oil consumed and BMI of adult women and men in India, with emphasis on predominant consumption of mustard oil.

DESIGN

Two nationally representative data, the consumer expenditure survey of National Sample Survey Office (NSSO)-68th round (2011-2012) for food consumption and National Family Health Survey-4 (2015-2016) for weight status, were analysed. Data from both surveys were combined by matching households through common matching variables ('family size', 'religion', etc.) using Nearest-Neighbour Hot-Deck matching. The association of overweight/obesity with predominant mustard oil consumption in the household was examined using logistic regression adjusted for confounders. The NSSO reports household consumption of mustard, groundnut, coconut, refined oils (sunflower, safflower, soyabean) and all other edible oils.

SETTING

Two nationally representative surveys from India.

PARTICIPANTS

Total of 638 445 women and 92 312 men, respectively.

RESULTS

Mustard oil was the most predominantly consumed oil (51 %) followed by refined oils (32·4 %). Prevalence of overweight/obesity in women and men was lower in households with predominant mustard oil consumption (17 and 15 %) v. all other refined and other oils combined (27 and 26 %). The adjusted OR for predominant mustard oil use was 0·88 (95 % CI 0·86, 0·87) for women and 0·80 (95 % CI 0·76, 0·83) for men. A similar analysis with predominant groundnut oil consumption showed no association with overweight/obesity.

CONCLUSIONS

The data from a large national level survey suggest an inverse association between mustard oil consumption and overweight/obesity which needs to be explored with further research studies.

Conjugated Linoleic Acid and Brain Metabolism: A Possible Anti-Neuroinflammatory Role Mediated by PPARα Activation

Fatty acids play a crucial role in the brain as specific receptor ligands and as precursors of bioactive metabolites. Conjugated linoleic acid (CLA), a group of positional and geometric isomers of linoleic acid (LA, 18:2 n-6) present in meat and dairy products of ruminants and synthesized endogenously in non-ruminants and humans, has been shown to possess different nutritional properties associated with health benefits. Its ability to bind to peroxisome proliferator-activated receptor (PPAR) α, a nuclear receptor key regulator of fatty acid metabolism and inflammatory responses, partly mediates these beneficial effects. CLA is incorporated and metabolized into brain tissue where induces the biosynthesis of endogenous PPARα ligands palmitoylethanolamide (PEA) and oleoylethanolamide (OEA), likely through a positive feedback mechanism where PPARα activation sustains its own cellular effects through ligand biosynthesis. In addition to PPARα, PEA and OEA may as well bind to other receptors such as TRPV1, further extending CLA own anti-neuroinflammatory actions. Future studies are needed to investigate whether dietary CLA may exert anti-inflammatory activity, particularly in the setting of neurodegenerative diseases and neuropsychiatric disorders with a neuroinflammatory basis.

X-linked adrenoleukodystrophy: Pathology, pathophysiology, diagnostic testing, newborn screening and therapies

Adrenoleukodystrophy (ALD) is a rare X-linked disease caused by a mutation of the peroxisomal ABCD1 gene. This review summarizes our current understanding of the pathogenic cell- and tissue-specific roles of lipid species in the context of experimental therapeutic strategies and provides an overview of critical historical developments, therapeutic trials and the advent of newborn screening in the USA. In ALD, very long-chain fatty acid (VLCFA) chain length-dependent dysregulation of endoplasmic reticulum stress and mitochondrial radical generating systems inducing cell death pathways has been shown, providing the rationale for therapeutic moiety-specific VLCFA reduction and antioxidant strategies. The continuing increase in newborn screening programs and promising results from ongoing and recent therapeutic investigations provide hope for ALD.

X-linked Adrenoleukodystrophy: Pathology, Pathophysiology, Diagnostic Testing, Newborn Screening, and Therapies

Adrenoleukodystrophy (ALD) is a rare X-linked disease caused by a mutation of the peroxisomal ABCD1 gene. This review summarizes our current understanding of the pathogenic cell- and tissue-specific role of lipid species in the context of experimental therapeutic strategies and provides an overview of critical historical developments, therapeutic trials, and the advent of newborn screening in the United States. In ALD, very long chain fatty acid (VLCFA) chain-length-dependent dysregulation of endoplasmic reticulum stress and mitochondrial radical generating systems inducing cell death pathways has been shown, providing the rationale for therapeutic moiety-specific VLCFA reduction and antioxidant strategies. The continuing increase in newborn screening programs and promising results from ongoing and recent therapeutic investigations provide hope for ALD.

Late onset adrenoleukodystrophy: A review related clinical case report

Our objective is to review the initial presentation, evolution, progression, final stage, and images in the follow up of an adult patient who presented an uncommon peroxisomal disease (1/20,000 males) that occurred by ABCD1 gene mutation in the Xq28 chromosome; to bring forward the imaging features (which nowadays is the most useful and accessible diagnostic tool) and clinical presentation of adrenoleukodystrophy in adulthood; to propose a differential diagnosis in aid of a prompt recognition of the disease hereafter from a neurologist approach. In relation of a clinical case we reviewed the literature to correlate the principal findings and evolution of the disease. This thrilling but at the same time unfortunate disease is not only a diagnostic problem is also a therapeutic quest besides all the related familial, labor, and social related problems. The very-long chain fatty acids (VLCFA) accumulation leads to a not completely understood mechanisms that precipitate the specific malfunction of the nervous system and adrenal gland. The initial corticospinal bilateral involvement provokes a spastic paraparesis but with the affection of others pathways multiple manifestations appears, with dementia and finally loss of the most of cortical functions secondary to the white matter affection. Since the hematopoietic stem cell transplantation can be treated with variable results, other treatments, as the Lorenzo's oil, have not been consistent with a substantial improvement of the affected individual. The genetic advice and support to the patient and the family are essentials as well as the screening in individuals at risk before the onset of the disease.

A model-based approach to assess the exposure-response relationship of Lorenzo's oil in adrenoleukodystrophy

AIMS

X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder, most commonly affecting boys, associated with increased very long chain fatty acids (C26:0) in all tissues, causing cerebral demyelination and adrenocortical insufficiency. Certain monounsaturated long chain fatty acids including oleic and erucic acids, known as Lorenzo's oil (LO), lower plasma C26:0 levels. The aims of this study were to characterize the effect of LO administration on plasma C26:0 concentrations and to determine whether there is an association between plasma concentrations of erucic acid or C26:0 and the likelihood of developing brain MRI abnormalities in asymptomatic boys.

METHODS

Non-linear mixed effects modelling was performed on 2384 samples collected during an open label single arm trial. The subjects (n = 104) were administered LO daily at ~2-3 mg kg(-1) with a mean follow-up of 4.88 ± 2.76 years. The effect of erucic acid exposure on plasma C26:0 concentrations was characterized by an inhibitory fractional Emax model. A Weibull model was used to characterize the time-to-developing MRI abnormality.

RESULTS

The population estimate for the fractional maximum reduction of C26:0 plasma concentrations was 0.76 (bootstrap 95% CI 0.73, 0.793). Our time-to-event analyses showed that every mg l(-1) increase in time-weighted average of erucic acid and C26:0 plasma concentrations was, respectively, associated with a 3.7% reduction and a 753% increase in the hazard of developing MRI abnormality. However, the results were not significant (P = 0.5344, 0.1509, respectively).

CONCLUSIONS

LO administration significantly reduces the abnormally high plasma C26:0 concentrations in X-ALD patients. Further studies to evaluate the effect of LO on the likelihood of developing brain MRI abnormality are warranted.

A mixture of oleic, erucic and conjugated linoleic acids modulates cerebrospinal fluid inflammatory markers and improve somatosensorial evoked potential in X-linked adrenoleukodystrophy female carriers

X-linked adrenoleukodystrophy is a rare inherited demyelinating disorder characterized by an abnormal accumulation of very long chain fatty acids, mainly hexacosanoic acid (26:0), due to a mutation of the gene encoding for a peroxisomal membrane protein. The only available, and partially effective, therapeutic treatment consists of dietary intake of a 4:1 mixture of triolein and trierucin, called Lorenzo's oil (LO), targeted to inhibit the elongation of docosanoic acid (22:0) to 26:0. In this study we tested whether, besides inhibiting elongation, an enhancement of peroxisomal beta oxidation induced by conjugated linoleic acid (CLA), will improve somatosensory evoked potentials and modify inflammatory markers in adrenoleukodystrophy females carriers. We enrolled five heterozygous women. They received a mixture of LO (40 g/day) with CLA (5 g/day) for 2 months. The therapeutic efficacy was evaluated by the means of plasma levels of 26:0, 26:0/22:0 ratio, modification of cerebrospinal fluid (CSF) inflammatory markers and somatosensory evoked potentials. Changes of fatty acid profile, and in particular CLA incorporation, were also evaluated in CSF and plasma. The results showed that CLA promptly passes the blood brain barrier and the mixture was able to lower both 26:0 and 26:0/22:0 ratio in plasma. The mixture improved somatosensory evoked potentials, which were previously found unchanged or worsened with dietary LO alone, and reduced IL-6 levels in CSF in three out of five patients. Our data suggest that the synergic activity of CLA and LO, by enhancing peroxisomal beta-oxidation and preventing 26:0 formation, improves the somatosensory evoked potentials and reduces neuroinflammation.

Is subclinical adrenal failure in adrenoleukodystrophy/adrenomyeloneuropathy reversible?

BACKGROUND

X-linked adrenoleukodystrophy/adrenomieloneuropathy (ALD/AMN) is a progressive neurodegenerative disorder due to mutations in the ABCD1 gene encoding the ABC transporter ALDP. Mutations in ALDP impair peroxisomal β-oxidation of very long chain fatty acids (VLCFA), resulting in elevated levels of VLCFA in plasma, nervous system, and adrenals. Lorenzo's oil, combined with VLCFA- poor diet, normalizes plasma VLCFA within 1 month, but it does not prevent the progression of pre-existing neurological symptoms. No previous study analyzed the effect of Lorenzo's oil therapy on adrenal function.

AIM

To investigate short-term effects of Lorenzo's oil, combined with VLCFA- poor diet, on adrenal function of AMN patients with early subclinical signs of adrenal failure.

SUBJECTS AND METHODS

Seven AMN subjects underwent VLCFA-restricted diet combined with Lorenzo's oil (45 ml/day po), without steroid therapy, for 6 months.

RESULTS

All patients had elevated ACTH at baseline, and a significant reduction was evident after 6 months (median ACTH at baseline: 1300 pg/ml, range: 720- 2100; median ACTH at 6 months: 186 pg/ml, range: 109-320, p: 0.0156). Cortisol was normal both at baseline and after 6 months. VLCFA dropped in all patients during the 6- month follow-up, and no patient required glucocorticoid replacement therapy.

CONCLUSIONS

Adrenal insufficiency in ALD/AMN is probably due to a defective adrenal response to ACTH, related to VLCFA accumulation with progressive disruption of the adrenal cell membrane functions. In an early phase, Lorenzo's oil therapy may be able to improve VLCFA clearance and restore a normal ACTH receptor activity, and hypoadrenalism may be potentially reversible.

“Lorenzo’s Oil” Therapy for X-linked Adrenoleukodystrophy: Rationale and Current Assessment of Efficacy

X-linked adrenoleukodystrophy (X-ALD) is a genetic disorder that damages the nervous system and is associated with the accumulation of saturated very long chain fatty acids (SVLCFA). Oral administration of "Lorenzo's oil" (LO), a 4:1 mixture of glyceryl trioleate and glyceryl trierucate, normalizes the SVLCFA levels in plasma, but its clinical efficacy and the clinical indications for its use have been controversial for more than 15 years. We review the biochemical effects of LO administration and the rationale for its use and present a current appraisal of its capacity to reduce the risk for the childhood cerebral phenotype when administered to asymptomatic boys and to slow progression of adrenomyeloneuropathy in patients without cerebral involvement. We also present current efforts to provide definitive evaluation of its clinical efficacy and discuss its possible role in the new therapeutic opportunities that will arise if newborn screening for X-ALD is validated and implemented.

Uptake and metabolism of plasma-derived erucic acid by rat brain

We examined the ability of erucic acid (22:1n-9) to cross the blood-brain barrier (BBB) by infusing [14-14C]22:1n-9 (170 microCi/kg, iv and icv) into awake, male rats. [1-14C]arachidonic acid (20:4n-6) [intravenous (i.v.)] was the positive control. After i.v. infusion, 0.011% of the plasma [14-14C]22:1n-9 was extracted by the brain, compared with 0.055% of the plasma [1-14C]20:4n-6. The [14-14C]22:1n-9 was extensively beta-oxidized (60%), compared with 30% for [1-14C]20:4n-6. Although 20:4n-6 was targeted primarily to phospholipid pools, 22:1n-9 was targeted to cholesteryl esters, triglycerides, and phospholipids. When [14-14C]22:1n-9 was infused directly into the fourth ventricle of the brain [intracerebroventricular (i.c.v.)] for 7 days, 60% of the tracer entered the phospholipid pools, similar to the distribution observed for [1-14C]20:4n-6. This demonstrates plasticity in the ability of the brain to esterify 22:1n-9 in an exposure-dependent manner. In i.v. and i.c.v. infused rats, a significant amount of tracer found in the phospholipid pools underwent sequential rounds of chain shortening and was found as [12-14C]20:1n-9 and [10-14C]oleic acid. These results demonstrate for the first time that intact 22:1n-9 crosses the BBB, is incorporated into specific lipid pools, and is chain-shortened.

Treatment of X-linked childhood cerebral adrenoleukodystrophy by the use of an allogeneic stem cell transplantation with reduced intensity conditioning regimen

Childhood cerebral form of X-linked adrenoleukodystrophy (X-ALD) is a rapidly progressive demyelinating condition affecting the cerebral white matter, which rapidly leads to total disability and death. The only known curative treatment for this condition is allogeneic hematopoietic stem cell transplantation (HSCT). Procedure-related toxicity is assumed to be the cause of death of patients with X-ALD. Three cases of ALD successfully transplanted with the use of non-myeloablative fludarabine based conditioning are described. Patients showed smooth peri-bone marrow transplantation course with fast and stable engraftment. In the 3- to 5 yr follow-up period, patients showed no deterioration in their clinical and neurological condition. Levels of very long chain fatty acids were very variable and had a tendency to decrease in at least one of the three patients. In another patient, an improvement of magnetic resonance imaging changes was found. Non-myeloablative HSCT should be considered as an early treatment for X-ALD.

Elongation of very long-chain fatty acids is enhanced in X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a progressive neurodegenerative disorder characterized by the accumulation of saturated and mono-unsaturated very long-chain fatty acids (VLCFA) and reduced peroxisomal VLCFA beta-oxidation activity. In this study, we investigated the role of VLCFA biosynthesis in X-ALD fibroblasts. Our data demonstrate that elongation of both saturated and mono-unsaturated VLCFAs is enhanced in fibroblasts from patients with peroxisomal beta-oxidation defects including X-ALD, and peroxisome biogenesis disorders. These data indicate that enhanced VLCFA elongation is a general phenomenon associated with an impairment in peroxisomal beta-oxidation, and not specific for X-ALD alone. Analysis of plasma samples from patients with X-ALD and different peroxisomal beta-oxidation deficiencies revealed increased concentrations of VLCFAs up to 32 carbons. We infer that enhanced elongation does not result from impaired peroxisomal beta-oxidation alone, but is due to the additional effect of unchecked chain elongation. We demonstrate that elongated VLCFAs are incorporated into complex lipids. The role of chain elongation was also studied retrospectively in samples from patients with X-ALD previously treated with "Lorenzo's oil." We found that the decrease in plasma C26:0 previously found is offset by the increase of mono-unsaturated VLCFAs, not measured previously during the trial. We conclude that evaluation of treatment protocols for disorders of peroxisomal beta-oxidation making use of plasma samples should include the measurement of saturated and unsaturated VLCFAs of chain lengths above 26 carbon atoms. We also conclude that chain elongation offers an interesting target to be studied as a possible mode of treatment for X-ALD and other peroxisomal beta-oxidation disorders.

The genetics of ATP-binding cassette transporters

The ATP-binding cassette (ABC) superfamily consists of membrane proteins that transport a wide variety of substrates across membranes. Mutations in ABC transporters cause or contribute to a number of different Mendelian disorders, including adrenoleukodystrophy, cystic fibrosis, retinal degeneration, cholesterol, and bile transport defects. In addition, the genes are involved in an increasing number of complex disorders. The proteins play essential roles in the protection of organisms from toxic metabolites and compounds in the diet and are involved in the transport of compounds across the intestine, blood-brain barrier, and the placenta. There are 48 ABC genes in the human genome divided into seven subfamilies based in gene structure, amino acid alignment, and phylogenetic analysis. These seven subfamilies are found in all other sequenced eukaryotic genomes and are of ancient origin. Further characterization of all ABC genes from humans and model organisms will lead to additional insights into normal physiology and human disease.

Therapeutic effects of normal cells on ABCD1 deficient cells in vitro and hematopoietic cell transplantation in the X-ALD mouse model

Bone marrow transplantation (BMT) is accepted as an efficient therapy for X-linked adrenoleukodystrophy (ALD). To clarify the mechanisms of this treatment, we examined the effects of hematopoietic cell transplantation (HCT) in an ATP-binding cassette, subfamily D, member 1 (ABCD1) knock out mice and co-culture of ALD patient fibroblasts with normal cells. We treated ABCD1 knock out mice with HCT using lacZ-transgenic mice as donors, which enabled us to detect donor-derived cells. We also examined the effects of co-culturing a normal microglia cell line (N9) with ALD fibroblasts. beta-Galactosidase (beta-GAL) activity was higher in spleen, lung and kidney than in liver, brain and spinal cord of the recipient ABCD1 knock out mice. HCT reduced the accumulation of very long chain fatty acid (VLCFA) in those tissues. The reduction of the VLCFA ratio was significant in spleen and lung; tissues with higher beta-GAL activity. ABCD1 was detectable in spleen from HCT mice. Co-culture of ALD fibroblasts with normal fibroblast cells reduced VLCFA accumulation in ALD cells. This effect was not observed when the cells were co-cultured while separated by a filter membrane. Our data suggest that supplying normal cells for ABCD1 knockout mouse by HCT corrects metabolic abnormalities in ALD tissues through a cell-mediated process. The correction requires direct cell-to-cell contact for recovering normal cell function.

Pex13 inactivation in the mouse disrupts peroxisome biogenesis and leads to a Zellweger syndrome phenotype

Zellweger syndrome is the archetypical peroxisome biogenesis disorder and is characterized by defective import of proteins into the peroxisome, leading to peroxisomal metabolic dysfunction and widespread tissue pathology. In humans, mutations in the PEX13 gene, which encodes a peroxisomal membrane protein necessary for peroxisomal protein import, can lead to a Zellweger phenotype. To develop mouse models for this disorder, we have generated a targeted mouse with a loxP-modified Pex13 gene to enable conditional Cre recombinase-mediated inactivation of Pex13. In the studies reported here, we crossed these mice with transgenic mice that express Cre recombinase in all cells to generate progeny with ubiquitous disruption of Pex13. The mutant pups exhibited many of the clinical features of Zellweger syndrome patients, including intrauterine growth retardation, severe hypotonia, failure to feed, and neonatal death. These animals lacked morphologically intact peroxisomes and showed deficient import of matrix proteins containing either type 1 or type 2 targeting signals. Biochemical analyses of tissue and cultured skin fibroblasts from these animals indicated severe impairment of peroxisomal fatty acid oxidation and plasmalogen synthesis. The brains of these animals showed disordered lamination in the cerebral cortex, consistent with a neuronal migration defect. Thus, Pex13(-/-) mice reproduce many of the features of Zellweger syndrome and PEX13 deficiency in humans.

Biochemical effect of intravenous arginine butyrate in X-linked adrenoleukodystrophy

OBJECTIVES

To determine the biochemical and clinical effects of intravenous arginine butyrate in X-linked Adrenoleukodystrophy (X-ALD).

STUDY DESIGN

Arginine butyrate was intravenously infused over a 4-month period in a patient with the rapid cerebral form of X-ALD. Very long chain fatty acids (VLCFA), complete blood counts, and serum chemistries were monitored, and serial MRI of the brain and clinical neurologic examinations were performed.

RESULTS

All blood chemical and hematologic values remained within the normal range for age throughout the therapy. After completion of the first day of infusion, the C 26:0 value fell from 1.01 microg/mL to 0.445 microg/mL, which is below the mean value for an X-ALD heterozygote. Throughout the remainder of the trial, all C26:0 levels fell below the mean -1 SD for X-ALD hemizygotes (mean, 1.18 microg/mL, 1 SD = 0.53), ranging from 0.321 to 0.565 microg/mL. Despite reduction of the plasma VLCFA, the patient continued to deteriorate neurologically.

CONCLUSIONS

Intravenous arginine butyrate resulted in a rapid decrease in plasma VLCFA but no effect on the neurologic progression of the disease in this patient. Additional studies are needed to determine minimum effective dosage and interval, what proportion of patients respond, and whether the agent can prevent neurologic degeneration.

Elovl1 and p55Cdc genes are localized in a tail-to-tail array and are co-expressed in proliferating cells

Elovl1 is a ubiquitously expressed gene, the product of which belongs to a highly conserved family of microsomal enzymes, which are involved in the formation of very long chain fatty acids and sphingolipids in yeast to man. To elucidate the structure and regulation of the Elovl gene we have isolated a lambda phage genomic DNA clone containing the entire mouse gene and found that Elovl1 consists of eight exons that are dispersed over 5.4 kb of genomic sequence. Interestingly, sequencing of the lambda clone to completion revealed that the insert contained a segment of the cell cycle gene p55Cdc directed in the opposite orientation. The genes are very tightly linked so that the 3'-end of the long mRNA species are complementary over a short stretch of nucleotides. Although both Elovl1 and p55Cdc are highly conserved genes, a BLAST search implies that the tail-to-tail arrangement has evolved in vertebrates. Despite the non-similar expression pattern in different tissues, mRNA analysis of the two genes disclosed simultaneous transcription during a proliferation-differentiation transition state, which suggests that the two genes may be regulated through a common bi-directional transcription mechanism under specific conditions.

Molecular analysis of genomic DNA allows rapid, and accurate, prenatal diagnosis of peroxisomal D-bifunctional protein deficiency

Prenatal diagnosis was requested for a couple with a previous child affected by the peroxisomal disorder D-bifunctional protein deficiency. Prior analysis of the D-bifunctional protein cDNA sequence from the propositus had shown that it was missing 22 bp. This was subsequently attributed to a point mutation in the intron 5 donor site (IVS5 + 1G>C) of the D-bifunctional protein gene. Consistent with parental consanguinity, the patient was shown to be homozygous for this mutation, which is associated with loss of a Hph 1 restriction site in the genomic sequence. Prenatal testing of the fetus using genomic DNA isolated from uncultured amniocytes indicated that both alleles of the D-bifunctional protein had the IVS5 + 1G>C substitution. The peroxisomal defect was later confirmed biochemically using cultured amniocytes, which were found to have elevated levels of very long chain fatty acids (VLCFA). This is the first report of prenatal diagnosis of D-bifunctional protein deficiency using molecular analysis of genomic DNA.

Correlation among genotype, phenotype, and biochemical markers in Gaucher disease: implications for the prediction of disease severity

Gaucher disease is a lysosomal storage disorder characterized by a deficiency of the enzyme acid beta-glucosidase. The clinical manifestations of Gaucher disease are highly variable, and although certain genotypes are often associated with mild or severe symptoms, a defined correlation between genotype and phenotype does not exist. Identification of biochemical markers characteristic of pathology may be of use in predicting the progression of the disease state. In this study the relationship among genotype, glycolipid substrates, lysosomal proteins, and the clinical manifestations of Gaucher disease has been evaluated. Plasma glycolipids were analyzed using electrospray ionization-tandem mass spectrometry. Lysosomal-associated membrane protein-1 (LAMP-1) and saposin C were determined by immunoquantification. Patients with Gaucher disease were shown to have an increased 16:0-glucosylceramide/16:0-lactosylceramide ratio and elevated concentrations of LAMP-1 and saposin C in plasma. A general relationship was found to exist among the 16:0-glucosylceramide/16:0-lactosylceramide ratio, LAMP-1 and saposin C levels, and patient phenotype, providing a refinement of the genotype-phenotype correlation. These findings have major implications for the diagnosis, prediction of disease severity, and monitoring of therapy in patients with Gaucher disease.

ABCD1 mutations and the X-linked adrenoleukodystrophy mutation database: role in diagnosis and clinical correlations

X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene, which encodes a peroxisomal ABC half-transporter (ALDP) involved in the import of very long-chain fatty acids (VLCFA) into the peroxisome. The disease is characterized by a striking and unpredictable variation in phenotypic expression. Phenotypes include the rapidly progressive childhood cerebral form (CCALD), the milder adult form, adrenomyeloneuropathy (AMN), and variants without neurologic involvement. There is no apparent correlation between genotype and phenotype. In males, unambiguous diagnosis can be achieved by demonstration of elevated levels of VLCFA in plasma. In 15 to 20% of obligate heterozygotes, however, test results are false-negative. Therefore, mutation analysis is the only reliable method for the identification of heterozygotes. Since most X-ALD kindreds have a unique mutation, a great number of mutations have been identified in the ABCD1 gene in the last seven years. In order to catalog and facilitate the analysis of these mutations, we have established a mutation database for X-ALD ( http://www.x-ald.nl). In this review we report a detailed analysis of all 406 X-ALD mutations currently included in the database. Also, we present 47 novel mutations. In addition, we review the various X-ALD phenotypes, the different diagnostic tools, and the need for extended family screening for the identification of new patients.

The relationship between age and the fatty acid composition of cerebral cortex and erythrocytes in human subjects

The important role that neural tissue fatty acid composition plays in neurodevelopment and various pathological states is increasingly recognized. However, there are limited data regarding the fatty acid composition of normal human brain at various ages. The purpose of this study was to describe human cerebral cortex fatty acid composition from ages 2 to 88 years. The relationship between cerebral cortex and erythrocyte fatty acid composition was also investigated. Samples of frontal cerebral cortex and of erythrocytes were obtained from 58 human subjects on whom autopsies were performed. The mean age of subjects was 40 +/- 29 years, with a range of 2 to 88 years. The fatty acid composition of tissues was determined, and linear regression models were used to describe the relationship between age and the fatty acid composition of cerebral cortex and erythrocytes. The data were bilinear, with changes occurring after the approximate age of 18 years. Therefore, the cohort was divided into subjects with ages < or =18 and >18 years. In the younger group, the polyunsaturated fatty acids generally decreased with age, with the exception of 22:6n3, which demonstrated a significant increase. The level of mono-unsaturated fatty acids, in contrast, generally increased to the age of 18 years. Several of the polyunsaturated fatty acids also decreased with age in the older cohort, particularly 20:4n6. The levels of 18:2n6, however, increased significantly with age in the older cohort. Among subjects < or =18 years of age, there was no significant relationship between cerebral cortex and erythrocyte fatty acid levels. In the older cohort, there was a significant relationship between brain and erythrocyte levels for several fatty acids, particularly 16:0. These data demonstrate that levels of cerebral cortex fatty acids change from early childhood through late adulthood, and indicate that the levels of several erythrocyte fatty acids may be useful in predicting brain fatty acid levels in adults.

Evaluation of pharmacological induction of fatty acid beta-oxidation in X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is an inherited neurometabolic disorder associated with elevated levels of saturated unbranched very-long-chain fatty acids (VLCFA; C > 22:0) in plasma and tissues, and reduced VLCFA beta-oxidation in fibroblasts, white blood cells, and amniocytes from X-ALD patients. The X-ALD gene (ABCD1) at Xq28 encodes the adrenoleukodystrophy protein (ALDP) that is related to the peroxisomal ATP-binding cassette (ABCD) transmembrane half-transporter proteins. The function of ALDP is unknown and its role in VLCFA accumulation unresolved. Previously, our laboratory has shown that sodium 4-phenylbutyrate (4PBA) treatment of X-ALD fibroblasts results in increased peroxisomal VLCFA beta-oxidation activity and increased expression of the X-ALD-related protein, ALDRP, encoded by the ABCD2 gene. In this study, the effect of various pharmacological agents on VLCFA beta-oxidation in ALD mouse fibroblasts is tested. 4PBA, styrylacetate and benzyloxyacetate (structurally related to 4PBA), and trichostatin A (functionally related to 4PBA) increase both VLCFA (peroxisomal) and long-chain fatty acid [LCFA (peroxisomal and mitochondrial)] beta-oxidation. Isobutyrate, zaprinast, hydroxyurea, and 5-azacytidine had no effect on VLCFA or LCFA beta-oxidation. Lovastatin had no effect on fatty acid beta-oxidation under normal tissue culture conditions but did result in an increase in both VLCFA and LCFA beta-oxidation when ALD mouse fibroblasts were cultured in the absence of cholesterol. The effect of trichostatin A on peroxisomal VLCFA beta-oxidation is shown to be independent of an increase in ALDRP expression, suggesting that correction of the biochemical abnormality in X-ALD is not dependent on pharmacological induction of a redundant gene (ABCD2). These studies contribute to a better understanding of the role of ALDP in VLCFA accumulation and may lead to the development of more effective pharmacological therapies.

Characterization of urinary sulfatides in metachromatic leukodystrophy using electrospray ionization-tandem mass spectrometry

Metachromatic leukodystrophy is an inherited disorder characterized by a deficiency of the lysosomal enzyme arylsulfatase A and the subsequent accumulation of sulfatide in neural and visceral tissues. Clinical diagnosis is usually confirmed by in vitro analysis of arylsulfatase A activity, but may be complicated in cases of arylsulfatase A pseudodeficiency and sphingolipid activator protein deficiency. Large quantities of sulfatide can be detected in the urinary sediment of affected individuals and its measurement can aid in diagnosis. A number of complex methods have been described for the measurement of urinary sulfatide excretion. We have developed a rapid, sensitive, and specific mass spectrometric method for determining urinary sulfatide concentration of metachromatic leukodystrophy patients. Sulfatides are extracted from urine and then directly analyzed using electrospray ionization-tandem mass spectrometry. A sulfatide internal standard has been employed for quantification. The assay has demonstrated significant elevations in the concentrations of several hydroxy and nonhydroxy molecular species of sulfatide in the urine of metachromatic leukodystrophy patients compared to age-matched controls. Analysis of urinary sulfatides in arylsulfatase A pseudodeficiency patients showed a mild elevation in some individuals when related to urinary phosphatidylcholine.

Evolution of phenotypes in adult male patients with X-linked adrenoleukodystrophy

Our objective was to study the phenotype evolution of X-linked adrenoleukodystrophy (X-ALD) and the relation between axonal degeneration and cerebral demyelination. Although different X-ALD phenotypes are recognized, little is known about their evolution. Neuropathological and electrophysiological studies have shown that X-ALD is a disease with mixed features of axonal degeneration, leading to myeloneuropathy, and a severe inflammatory reaction in the cerebral white matter, resulting in demyelination. Retrospectively, 129 men with X-ALD were studied who were 1) at least 20 years presently or at the time of death, and 2) regularly monitored. Phenotype assignments were made at diagnosis and at present, or at death, using medical history and findings of neurological examination. Handicap was studied with the modified Rankin scale, and cerebral abnormalities with the X-ALD MRI severity (Loes) score. The mean follow-up interval was 10.1 +/- 5.0 years. Among 32 patients neurologically asymptomatic at diagnosis, 16 (50%) developed neurological deficits. Among 68 adrenomyeloneuropathy (AMN) patients initially without clinical brain involvement, 13 (19%) additionally developed cerebral demyelination. In a subset of 60 AMN patients, a moderate handicap evolved over a period of 16.2 +/- 8.9 years. Among 13 AMN patients with additional definite or probable cerebral involvement at diagnosis, eight died and one remained in a vegetative state. Most of the 16 patients with the cerebral phenotypes deteriorated. There is a high risk for adult neurologically asymptomatic patients to develop neurological deficits and for AMN patients to develop cerebral demyelination. Axonal degeneration and cerebral demyelination emerge in X-ALD independently of each other. This may have implications for the phenotype classification, the search for modifying factors, and the development and evaluation of new therapies.

Progression of abnormalities in adrenomyeloneuropathy and neurologically asymptomatic X-linked adrenoleukodystrophy despite treatment with "Lorenzo's oil"

OBJECTIVES

X-linked adrenoleukodystrophy (X-ALD) is an inherited disorder of peroxisomal fatty acid oxidation, biochemically characterised by the accumulation of saturated very long chain fatty acids (VLCFAs), particularly hexacosanoic acid (C26:0). Dietary treatment with a 4:1 mixture of glyceroltrioleate and glyceroltrierucate ("Lorenzo's oil") normalises plasma VLCFA concentrations, but neither ameliorates nor arrests the rapid progression of neurological symptoms in the cerebral variants of X-ALD. The efficacy of "Lorenzo's oil" in the milder phenotypes of X-ALD was assessed, as this has been much less investigated.

METHODS

Twenty two patients who were treated with "Lorenzo's oil" for at least 12 months for a median period of 2.5 (range 1.0-6.0) years were studied. Two had asymptomatic ALD, four the "Addison only" variant, 13 adrenomyeloneuropathy (AMN), and three were symptomatic female carriers.

RESULTS

The plasma C26:0 concentration normalised or near normalised in 19 patients (86%), in the three others it decreased significantly. Nevertheless, disability as measured with the extended disability status scale score increased mildly (0.5 (95% confidence interval (95% CI) 0.25-1.0)) in the 16 patients with neurological symptoms. Furthermore, one "Addison only" patient and one patient with AMN developed cerebral demyelination, and another "Addison only" patient developed AMN. Adrenocortical insufficiency evolved in one patient with AMN, and hypogonadism in one patient with asymptomatic ALD and two patients with AMN. Nerve conduction, evoked potential studies (SEP, BAEP, VEP), and abnormalities on cerebral MRI did not improve. On the other hand, side effects were often noted-namely, mild increases in liver enzymes (55%), thrombocytopenia (55%), gastrointestinal complaints (14%), and gingivitis (14%). We also found a mild decrease in haemoglobin concentration and leucocyte count.

CONCLUSIONS

The data suggest that treatment with "Lorenzo's oil" neither improved neurological or endocrine function nor arrested progression of the disease. Furthermore, the oil often induced adverse effects. Therefore, it is advocated that "Lorenzo's oil" should not be prescribed routinely to patients with X-ALD who already have neurological deficits.

Metabolism of trideuterated iso-lignoceric acid in rats in vivo and in human fibroblasts in culture

Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders, but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-2H3]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger's syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the omega-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal beta-oxidation because they are metabolized by the same pathways as the corresponding n-VLCFA. Moreover, as iso-VLCFA and their beta-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured.

Neurophysiologic follow-up of long-term dietary treatment in adult-onset adrenoleukodystrophy

OBJECTIVE

To monitor the effects of dietary treatment in adult-onset adrenoleukodystrophy (ALD) by means of somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs).

BACKGROUND

SEPs and MEPs have proved useful in revealing signs of progressively severe, central dying-back axonopathy in early stages of adult-onset ALD.

METHODS

Eight patients with adult-onset ALD underwent clinical examination, brain and spine MRI, and SEP and MEP studies before and after 3 years of Lorenzo's oil dietary therapy.

RESULTS

Before treatment, brain MRI was normal in five patients. Three of these patients had pure spinal SEP abnormalities and in the remaining two patients SEPs showed signs of involvement of both the spinal and cerebral somatosensory tracts. After treatment, the three patients with pure spinal abnormalities showed clinical and neurophysiologic worsening, whereas the two patients with a more advanced stage of disease (exhibited by SEPs) showed substantially unchanged clinical and neurophysiologic features. The patients with abnormal brain MRI at the onset of treatment showed clinical and neurophysiologic worsening.

CONCLUSIONS

Lorenzo's oil therapy had no effect on patients with evidence of inflammatory brain lesions. Moreover, in patients without clear signs of inflammatory damage, this treatment does not modify significantly the natural course of the disease. However, because effective treatments should begin before the onset of severe neurologic symptoms, SEPs and MEPs should be considered to evaluate the effectiveness of other experimental treatments in the patient with a negative brain MRI.

Determination of very-long-chain fatty acids in serum by gas chromatography-nitrogen-phosphorus detection following cyanomethylation

A sensitive method for very-long-chain fatty acid analysis was developed by gas chromatography-nitrogen-phosphorus detection by using cyanomethyl derivatization. Bromoacetonitrile as alkylating reagent was used to improve nitrogen phosphorus detection detectability of compounds containing non-nitrogen. The carboxyl group of very-long-chain fatty acid was alkylated to cyanomethyl esters. Reaction conditions were 40 min at 60 degrees C under potassium carbonate base. Heptacosanoic acid was used as an internal standard and hexane was used as a solvent of extraction. The extraction yield was 82.8% or more, relative standard deviation of the precision test was 8.3% or more and the result of linearity test showed a good correlation coefficient of r2=0.999 in the range of 0.1-50 microg/ml. The quantification limits were 10 ng/ml when 0.5 ml of serum was used. The present method proved simple, rapid, inexpensive and resistant to contaminants. When it was applied to serum samples taken from patients with X-linked adrenoleukodystrophy which is a hereditary X-linked disorder characterized by progressive demyelination and adrenal insufficiency during childhood, relative increase of the concentration of hexacosanoic acid and the concentration ratios of hexacosanoic, lignoceric to behenic acid was observed in comparison with control samples.

Gene redundancy and pharmacological gene therapy: implications for X-linked adrenoleukodystrophy

As more functional redundancy in mammalian cells is discovered, enhanced expression of genes involved in alternative pathways may become an effective form of gene therapy. X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder with impaired very-long-chain fatty acid metabolism. The X-ALD gene encodes a peroxisomal membrane protein (ALDP) that is part of a small family of related peroxisomal membrane proteins. We show that 4-phenylbutyrate treatment of cells from both X-ALD patients and X-ALD knockout mice results in decreased levels of and increased beta-oxidation of very-long-chain fatty acids; increased expression of the peroxisomal protein ALDRP; and induction of peroxisome proliferation. We also demonstrate that ALDP and ALDRP are functionally related, by ALDRP cDNA complementation of X-ALD fibroblasts. Finally, we demonstrate the in vivo efficacy of dietary 4-phenylbutyrate treatment through its production of a substantial reduction of very-long-chain fatty acid levels in the brain and adrenal glands of X-ALD mice.

A Japanese family with adrenoleukodystrophy with a codon 291 deletion: a clinical, biochemical, pathological, and genetic report

We report a Japanese family with adrenoleukodystrophy (ALD) with a three base pair deletion (delGAG 291) in the ALD gene. A variety of phenotypes were observed within this family. While the proband (patient 1) was classified as having a rare intermediate type of adult cerebral and cerebello-brain stem forms, his younger brother (patient 2) and nephew (patient 3) had a childhood ALD type. Another nephew (patient 4) of patient 1 was classified as having an adolescent form. The tau level in the cerebrospinal fluid (CSF) in patient 1 was as high as that of patients with Alzheimer's disease (AD). His brain magnetic resonance image (MRI) showed abnormalities in the bilateral cerebellar hemispheres and brain stem, but not in the cerebral white matter, where marked reductions of the cerebral blood flow and oxygen metabolism were clearly demonstrated by positron emission tomography (PET). In patients 2 and 3, the autopsy findings showed massive demyelination of the cerebral white matter with sparing of the U-fibers, compatible with the findings of childhood ALD. Oleic and erucic acids (Lorenzo's Oil) were administered to patients 1 and 4, but sufficient effectiveness was not obtained. The findings in this family suggest that delGAG291 is part of the cause of Japanese ALD with phenotypic variations. Moreover, although the scale of the study is limited, there is a possibility that PET can detect an insidious lesion which is undetectable by computed tomogram (CT) or MRI analysis, and that the higher level of tau reflects the process of neuronal degeneration in ALD. Lorenzo's Oil should be given in the early stage.

A mouse model for X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder with impaired beta-oxidation of very long chain fatty acids (VLCFAs) and reduced function of peroxisomal very long chain fatty acyl-CoA synthetase (VLCS) that leads to severe and progressive neurological disability. The X-ALD gene, identified by positional cloning, encodes a peroxisomal membrane protein (adrenoleukodystrophy protein; ALDP) that belongs to the ATP binding cassette transporter protein superfamily. Mutational analyses and functional studies of the X-ALD gene confirm that it and not VLCS is the gene responsible for X-ALD. Its role in the beta-oxidation of VLCFAs and its effect on the function of VLCS are unclear. The complex pathology of X-ALD and the extreme variability of its clinical phenotypes are also unexplained. To facilitate understanding of X-ALD pathophysiology, we developed an X-ALD mouse model by gene targeting. The X-ALD mouse exhibits reduced beta-oxidation of VLCFAs, resulting in significantly elevated levels of saturated VLCFAs in total lipids from all tissues measured and in cholesterol esters from adrenal glands. Lipid cleft inclusions were observed in adrenocortical cells of X-ALD mice under the electron microscope. No neurological involvement has been detected in X-ALD mice up to 6 months. We conclude that X-ALD mice exhibit biochemical defects equivalent to those found in human X-ALD and thus provide an experimental system for testing therapeutic intervention.

X linked adrenoleukodystrophy: clinical presentation, diagnosis, and therapy

X linked adrenoleukodystrophy (X-ALD) is an inherited disorder of peroxisomal metabolism, biochemically characterised by accumulation of saturated very long chain fatty acids. Accumulation of these fatty acids is associated with cerebral demyelination, peripheral nerve abnormalities, and adrenocortical and testicular insufficiency. The lowest estimated birth incidence is one per 100,000. At least six phenotypes can be distinguished, of which the two most frequent are childhood cerebral ALD and adrenomyeloneuropathy. The X-ALD gene has been identified, but thus far no relation between genotype and phenotype has been found. Diagnosis is relatively easy and can be confirmed reliably, and prenatal testing is possible in affected families. Several therapeutic options, some with promising perspectives, are available. Neurologists and other physicians seem not to be familiar with the many facets of X-ALD. In this review, the clinical presentation, the relative frequencies of the different phenotypes, and the diagnostic and therapeutic options are presented.

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.

Very long-chain fatty acids in diagnosis, pathogenesis, and therapy of peroxisomal disorders

Abnormally high levels of very long-chain fatty acids (VLCFA) are a feature in nine of the fifteen peroxisomal disorders that have been identified so far. Saturated VLCFA accumulate in X-linked adrenoleukodystrophy, appear to disrupt membrane structure, and may play a role in the pathogenesis of a brain inflammatory response. Dietary therapy initiated when patients are still asymptomatic may be of clinical benefit.

Oxidation of pristanic acid in fibroblasts and its application to the diagnosis of peroxisomal beta-oxidation defects

Pristanic acid oxidation measurements proved a reliable tool for assessing complementation in fused heterokaryons from patients with peroxisomal biogenesis defects. We, therefore, used this method to determine the complementation groups of patients with isolated defects in peroxisomal beta-oxidation. The rate of oxidation of pristanic acid was reduced in affected cell lines from all of the families with inherited defects in peroxisomal beta-oxidation, thus excluding the possibility of a defective acyl CoA oxidase. Complementation analyses indicated that all of the patients belonged to the same complementation group, which corresponded to cell lines with bifunctional protein defects. Phytanic acid oxidation was reduced in fibroblasts from some, but not all, of the patients. Plasma samples were still available from six of the patients. The ratio of pristanic acid to phytanic acid was elevated in all of these samples, as were the levels of saturated very long chain fatty acids (VLCFA). However, the levels of bile acid intermediates, polyenoic VLCFA, and docosahexaenoic acid were abnormal in only some of the samples. Pristanic acid oxidation measurements were helpful in a prenatal assessment for one of the families where previous experience had shown that cellular VLCFA levels were not consistently elevated in affected individuals.

Interactions of a very long chain fatty acid with model membranes and serum albumin. Implications for the pathogenesis of adrenoleukodystrophy

Adrenoleukodystrophy (ALD) is an inherited disorder of fatty acid metabolism marked by accumulation of very long chain saturated fatty acids (VLCFA), especially the 26-carbon acid, hexacosanoic acid (HA), in membranes and tissues. We have studied interactions of 13C-enriched HA with model membranes (phospholipid bilayer vesicles) and bovine serum albumin (BSA) by 13C NMR spectroscopy to compare properties of HA with those of typical dietary fatty acids. In phospholipid bilayers the carboxyl group of HA is localized in the aqueous interface, with an apparent pKa (7.4) similar to other fatty acids; the acyl chain must then penetrate very deeply into the membrane. Desorption of HA from vesicles (t1+2 = 3 h) is orders of magnitude slower than shorter chain fatty acids. In mixtures of vesicles and BSA, HA partitions much more favorably to phospholipid bilayers than typical fatty acids. BSA binds a maximum of only 1 mole of HA at one binding site. Calorimetric experiments show strong perturbations of acyl chains of phospholipids by HA. We predict that disruptive effects of VLCFA on cell membrane structure and function may explain the neurological manifestations of ALD patients. These effects will be further amplified by slow desorption of VLCFA from membranes and by the ineffective binding to serum albumin.

Adrenoleukodystrophy: molecular genetics, pathology, and Lorenzo's oil

Knowledge about adrenoleukodystrophy (ALD), a disorder which was described first in 1923, has increased greatly during recent years. The principal biochemical abnormality, the presumed enzyme defect, and the gene defect, have been defined. A dietary therapy has been proposed and attracted world-wide attention through a motion picture. Nevertheless, many questions remain and cannot be answered without a more fundamental understanding of pathology and pathogenesis. This article will provide a review of the history, clinical features, pathology, biochemistry, and the gene defect, and then appraise current efforts to clarify pathogenesis and develop therapeutic approaches.

Very long chain fatty acids in higher animals--a review

Fatty acids with greater than 22 carbon atoms (very long chain fatty acids, VLCFA) are present in small amounts in most animal tissues. Saturated and monoenoic VLCFA are major components of brain, while the polyenoic VLCFA occur in significant amounts in certain specialized animal tissues such as retina and spermatozoa. Biosynthesis of VLCFA occurs by carbon chain elongation of shorter chain fatty acid precursors while beta-oxidation takes place almost exclusively in peroxisomes. Mitochondria are unable to oxidize VLCFA because they lack a specific VLCFA coenzyme A synthetase, the first enzyme in the beta-oxidation pathway. VLCFA accumulate in the tissues of patients with inherited abnormalities in peroxisomal assembly, and also in individuals with defects in enzymes catalyzing individual reactions along the beta-oxidation pathway. It is believed that the accumulation of VLCFA in patient tissues contributes to the severe pathological changes which are a feature of these conditions. However, little is known of the role of VLCFA in normal cellular processes, and of the molecular basis for their contribution to the disease process. The present review provides an outline of the current knowledge of VLCFA including their biosynthesis, degradation, possible function and involvement in human disease.

Komrower Lecture. Adrenoleukodystrophy: natural history, treatment and outcome

Our laboratory has identified nearly 2000 patients with X-linked adrenoleukodystrophy (ALD) and conducted therapeutic trials in groups of patients who represent the major phenotypes. We report recent results of dietary therapy with a mixture of glyceryl trioleate and glyceryl trierucate oil, also referred to as Lorenzo's Oil, in the asymptomatic and childhood cerebral phenotypes. Fifty-three patients started this therapy at a mean age of 7.5 years at a time when they were free of neurological symptoms. Although analysis of data is hampered by the lack of a concurrent control group, follow-up studies after 39 months of therapy suggest that subsequent neurological involvement was less frequent and less severe than anticipated from historical controls. Retrospective analysis of the effect of the oil in patients with the severe childhood cerebral phenotype indicates that there was a slight but statistically significant slowing of clinical progression and delay of death.