Decreasing serum VLCFA levels in ageing X-ALD female carriers

Adrenoleukodystrophy is an X-linked severe demyelinating disease with pathognomonic accumulation of saturated very long-chain fatty acids (VLCFA) in tissues and body fluids in affected males. The identification of women heterozygotes is also based on increased serum VLCFA concentrations. We describe the results of measuring serum VLCFA concentrations in 59 females of various ages with heightened risk of carrier status. In female carriers aged 22–50 years we found serum VLCFA concentrations in a range characteristic of heterozygotes; VLCFA levels were normal in female carriers aged 55–64 years. In women aged 37–50 years in whom repeat studies of VLCFA concentration were performed after 5 years, a reduction in VLCFA was observed. The results we obtained point to a reduction of serum VLCFA concentrations as X-ALD heterozygotes age.     

X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (ALD) is a severe neurodegenerative disorder. ALD is characterized by progressive demyelination within the central and peripheral nervous system, adrenal insufficiency (Addison's disease) and accumulation of very-long-chain fatty acids (VLCFA) in plasma, fibroblasts and tissues. The overall incidence of ALD is 1:17,000 including hemizygotes and heterozygotes who are frequently symptomatic. There are two main ALD phenotypes: 1) a cerebral demyelinating form which affects boys between 5-12 years, but also 35% of adult males; 2) a form that mainly involves the spinal cord (adrenomyeloneuropathy, AMN) in adult males between 20-50 years and 50% of heterozygous women after the age of 40 years. AMN presents with progressive spastic paraparesis. Addison's disease may be the first symptom of ALD in boys and adult males. These patients are at risk to develop cerebral ALD or AMN for life. ALD results from mutations in the ABCD1 gene without correlation between genotype and phenotype. The diagnosis of ALD relies upon the measurement of plasma VLCFA levels that allows the identification of 100% affected males and of 80-95% heterozygous women. Because of these false-negative, it is therefore mandatory to search for a mutation in the ABCD1 gene in all women at risk to be heterozygous for ALD. The ABCD1 gene encodes a peroxisomal transmembrane protein (ALD protein) with the structure of an half ATP-binding cassette transporter. It is possible that ALD protein imports VLCFA or VLCFA-CoA into peroxisomes in which they are degraded by a peroxisomal beta-oxidation system. Elongation of VLCFAs is enhanced in fibroblasts from ALD patients and likely contributes to the load of VLCFA in tissues. The underlying mechanisms that lead to cerebral demyelination, axonal degeneration in spinal cord and adrenal insufficiency are unknown. The "toxic" role of VLCFA accumulation remains to be demonstrated. The mechanisms that lead to the inflammatory reaction in cerebral ALD might involve abnormal acylation of gangliosides and phospholipids by VLCFA that would result in immune reaction of brain macrophages and astrocytes bearing CD1 molecules that recognize lipid antigens. De novo mutation of ABCD1 occurs in less than 8% of ALD patients. The genetic counseling aims to identify: 1) women who are at risk to be heterozygous; 2) neurologically asymptomatic boys. It is only at this stage that allogeneic bone marrow transplantation has clinical benefit; 3) ALD patients who have Addison's disease that can lead to sudden death. Prenatal diagnosis (chorionic villus samples, cultured amniotic fluid cells) relies upon DNA based mutation detection techniques, expression of ALD protein and measurement of VLCFA levels. Allogeneic bone marrow transplantation is the only treatment that provides a permanent cure when the procedure is performed at an early stage of cerebral demyelination, i.e when the patients are asymptomatic despite abnormal brain MRI. Treatment of Addison's disease is mandatory but does not modify the course of neurological symptoms. Dietary therapy failed to halt the neurologic progression in cerebral ALD and AMN. It might have a partial preventive effect in boys treated before 6 years of age.     

Rolipram does not normalize very long-chain fatty acid levels in adrenoleukodystrophy protein-deficient fibroblasts and mice

In its severe form, X-linked adrenoleukodystrophy (X-ALD) is a lethal neurodegenerative disorder with inflammatory demyelination, in which defective peroxisomal -oxidation causes accumulation of very long-chain fatty acids (VLCFA) in tissues and plasma, in particular in the nervous system and adrenal glands. Recently, several drugs have been reported to reduce VLCFA in cultured human fibroblasts of X-ALD patients, and therefore to be potential candidates for novel therapeutic treatments in X-ALD. Among the most promising of these substances is the antidepressant rolipram, because of favourable adverse event profile in clinical studies and its additionally reported anti-inflammatory action. To further elucidate the effects of rolipram on peroxisomal -oxidation and VLCFA accumulation, we administered rolipram orally in the diet to ALD protein-deficient mice and ALD protein-deficient cultured human and mouse fibroblasts and assayed the accumulation of VLCFA. In contrast to the previously reported reduction of VLCFA, our data did not demonstrate a decrease in VLCFA content either in vivo or in vitro. NMR spectroscopic analysis verified the structural integrity and purity of the rolipram used here, thus excluding inauthenticity as a reason for the discrepancy. We therefore suggest that rolipram should be excluded from the current list of potential therapeutic agents for X-ALD.     

Bezafibrate lowers very long-chain fatty acids in X-linked adrenoleukodystrophy fibroblasts by inhibiting fatty acid elongation

X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene encoding ALDP, an ATP-binding-cassette (ABC) transporter located in the peroxisomal membrane. ALDP deficiency results in impaired peroxisomal β-oxidation and the subsequent accumulation of very long-chain fatty acids (VLCFA; > C22:0) in plasma and tissues. VLCFA are primarily derived from endogenous synthesis by ELOVL1. Therefore inhibiting this enzyme might constitute a feasible therapeutic approach. In this paper we demonstrate that bezafibrate, a PPAR pan agonist used for the treatment of patients with hyperlipidaemia reduces VLCFA levels in X-ALD fibroblasts. Surprisingly, the VLCFA-lowering effect was independent of PPAR activation and not caused by the increase in either mitochondrial or peroxisomal fatty acid β-oxidation capacity. In fact, our results show that bezafibrate reduces VLCFA synthesis by decreasing the synthesis of C26:0 through a direct inhibition of fatty acid elongation activity. Taken together, our data indicate bezafibrate as a potential pharmacotherapeutic treatment for X-ALD. A clinical trial is currently ongoing to evaluate the effect in patients with X-ALD.     

Characterization of X-linked adrenoleukodystrophy in different biological specimens from ten Portuguese families

Summary X-linked adrenoleukodystrophy (ALD) is a severe neurodegenerative disease characterized by progressive demyelination, adrenocortical insufficiency and accumulation in tissues and body fluids of unbranched, saturated very long-chain fatty acids (VLCFA). The diagnosis of ALD is usually based on clinical history, neurological examination and the determination of levels of VLCFA in plasma and cultured skin fibroblasts.In the present paper we report the biochemical findings in plasma, cultured skin fibroblasts and lymphoblastoid cell lines from ALD patients. The results obtained indicate that the increment of the ratios C_24:0 to C_22:0 and C_26:0 to C_22:0 and of the concentration C_26:0 (µg/ml) in plasma was parallel with that of fibroblasts, but not with that of Epstein-Barr virus (EBV)-transformed lymphocytes, suggesting that this cell line is not reliable for diagnosis of ALD by VLCFA analysis.Subsequent studies carried out on family members revealed heterozygotes other than obligate carriers and hemizygotes who were pre-symptomatic or had a misdiagnosis of multiple sclerosis or psychosis.     

Liver X receptor beta (LXRbeta): a link between beta-sitosterol and amyotrophic lateral sclerosis-Parkinson's dementia

Administration of β-sitosterol (42 mg/kg per day) for 3 weeks to 8-month-old male LXRβ^−/− mice resulted in the death of motor neurons in the lumbar region of the spinal cord and loss of tyrosine hydroxylase-positive dopaminergic neurons in the substantia nigra. In mice at 5 months of age, β-sitosterol had no observed toxicity but at 16 months of age, it caused severe paralysis and symptoms typical of dopaminergic dysfunction in LXRβ^−/− mice. WT mice were not affected by these doses of β-sitosterol. In 5-month-old mice, levels of the intestinal transporters, ABCG5/8 and Niemann-Pick C1 Like 1, were not affected by loss of liver X receptor (LXR) β and/or treatment with β-sitosterol nor were there changes in plasma levels of cholesterol or β-sitosterol. In 8-month-old LXRβ^−/− mice there was activation of microglia in the substantia nigra pars reticulata and aggregates of ubiquitin and TDP-43 in the cytoplasm of large motor neurons in the lumbar spinal cord. Brain cholesterol concentrations were higher in LXRβ^−/− than in their WT counterparts, and treatment with β-sitosterol reduced brain cholesterol in both WT and LXRβ^−/− mice. In LXRβ^−/− mice but not in WT mice levels of 24-hydrocholesterol were increased upon β-sitosterol treatment. These data indicate that multiple mechanisms are involved in the sensitivity of LXRβ^−/− mice to β-sitosterol. These include activation of microglia, accumulation of protein aggregates in the cytoplasm of large motor neurons, and depletion of brain cholesterol.     

Lovastatin specifically prevents focal ischemic ventricular tachycardia due to triggered activity.

BACKGROUND: Use of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor has been associated with reduced implantable defibrillator shocks in several multicenter trials, suggesting an antiarrhythmic effect. OBJECTIVE: The purpose of this study was to determine if lovastatin had an antiarrhythmic effect in a canine model of ischemic and inducible ventricular tachycardia (VT). METHODS: Forty-seven alpha-chloralose anesthetized dogs underwent left anterior descending coronary occlusion. Three-dimensional activation mapping identified the mechanism of reinducible VT and the response to lovastatin (0.5 mg/kg IV). The endocardium was excised from foci and studied using standard microelectrode techniques with Tyrode's solution. RESULTS: Lovastatin blocked focal VT in 8 of 13 dogs (P <.01) compared with only 1 of 12 saline-treated dogs with focal VT. Lovastatin had no effect on reentrant VT. Lovastatin did not alter the effective refractory period, arterial pressure, or percentage of ischemic electrograms. Effective plasma concentration of lovastatin hydroxy acid ranged from 21-157 ng/mL (0.8-3.7 x 10(-7) M). In vitro rapid pacing, mostly with isoproterenol (5 x 10(-7) M) superfusion, produced delayed afterdepolarizations and triggered activity (9 +/- 2 action potentials). Lovastatin (10(-7) M) produced no change in action potentials or delayed afterdepolarizations. However, triggered activity was attenuated to 2 +/- 1 action potentials with lovastatin (P <.05, n = 13) but not with vehicle alone. Triggered activity returned to control after lovastatin washout (20 minutes) as well as with co-superfusion with mevalonic acid (10(-6) M, n = 5). 2,2,6,6-Tetramethylpiperidine-N-oxyl, an antioxidant that enters tissues (10(-3) M, n = 8), prevented triggered activity in a fashion similar to lovastatin. CONCLUSION: Lovastatin, in concentrations achievable in human plasma, specifically suppresses triggered activity and focal VT due to ischemia. A prenylated protein downstream from mevalonic acid may act as an antioxidant, producing the antiarrhythmic effect.     

Neural deficits contribute to respiratory insufficiency in Pompe disease

Pompe disease is a severe form of muscular dystrophy due to glycogen accumulation in all tissues, especially striated muscle. Disease severity is directly related to the deficiency of acid α-glucosidase (GAA), which degrades glycogen in the lysosome. Respiratory dysfunction is a hallmark of the disease, muscle weakness has been viewed as the underlying cause, and the possibility of an associated neural contribution has not been evaluated previously. Therefore, we examined behavioral and neurophysiological aspects of breathing in 2 animal models of Pompe disease—the Gaa^−/− mouse and a transgenic line (MTP) expressing GAA only in skeletal muscle, as well as a detailed analysis of the CNS in a Pompe disease patient. Glycogen content was elevated in the Gaa^−/− mouse cervical spinal cord. Retrograde labeling of phrenic motoneurons showed significantly greater soma size in Gaa^−/− mice vs. isogenic controls, and glycogen was observed in Gaa^−/− phrenic motoneurons. Ventilation, assessed via plethysmography, was attenuated during quiet breathing and hypercapnic challenge in Gaa^−/− mice (6 to >21 months of age) vs. controls. We confirmed that MTP mice had normal diaphragmatic contractile properties; however, MTP mice had ventilation similar to the Gaa^−/− mice during quiet breathing. Neurophysiological recordings indicated that efferent phrenic nerve inspiratory burst amplitudes were substantially lower in Gaa^−/− and MTP mice vs. controls. In human samples, we demonstrated similar pathology in the cervical spinal cord and greater accumulation of glycogen in spinal cord compared with brain. We conclude that neural output to the diaphragm is deficient in Gaa^−/− mice, and therapies targeting muscle alone may be ineffective in Pompe disease.     

Endocrine disease in adrenoleukodystrophy

X-linked adrenoleukodysrophy is the most frequent genetic disorder affecting central and peripheral nervous system myelin. One of the biochemical abnormalities is the accumulation of very long chain fatty acids (VLCFA) in tissues and body fluids subsequent to defective catabolism in the peroxysomes. The principal characteristic of the disease is an association between a neurological disorder and an endocrine disorder: primary adrenal insufficiency and testicular failure. Clinical manifestations are variable. There are two main forms, one affecting boys between the age of 5 and 10 years with severe rapidly fatal cerebral involvement, and the other affecting young adults between the age of 20 and 30 years with degeneration of the anterior and posterior long spinal cord tracts, similar to the disorders observed in multiple sclerosis. About 20% of the heterozygous women may develop a syndrome which resembles adrenomyeloneuropathy, rarely adrenal insufficiency. Adrenal insufficiency is present in 85% of the childhood cerebral forms and in about 70% of the adult forms. It may occur before, after or at the same time as the neurological disease but is not correlated with the severity of the neurological disorder. Careful screening is required to avoid missing subclinical forms. Adrenoleukodystrophy should be envisaged in young boys with primary adrenal insufficiency, accounting for about 30% of the cases of primary adrenal insufficiency in children under 3 years of age and about 13% of those in adults. Experience with dietary therapy (low-VLCFA diet and supplementation with unsaturated fatty acids such as glyceryl trioleate (GTO) and glyceryl trierucate (GTE), commonly called Lorenzo's oil) has not demonstrated any clinical improvement in the cerebral forms. Bone marrow transplantation is recommended for children who show early evidence of cerebral involvement. Gene therapy is a promising perspective. Lovastatin and 4-phenlbutyrate have recently been shown to normalize plasma VLCFA levels. Their therapeutic efficacy must be assessed in a randomized trial.     

Failure of spinal cord oligodendrocyte development in mice lacking neuregulin

Oligodendrocytes develop from a subpopulation of precursor cells within the ventral ventricular zone of the spinal cord. The molecular cues that direct this spatially and temporally restricted event seem to originate in part from structures ventral to and within the spinal cord. Here, we present evidence that the family of ligands termed neuregulins are necessary for the normal generation of mouse spinal cord oligodendrocytes. Oligodendrocytes mature in spinal cord explants from wild-type mice and mice heterozygotic for a null mutation in the neuregulin gene (NRG +/−) in a temporal sequence of developmental events that replicates that observed in vivo. However, in spinal cord explants derived from mice lacking neuregulin (NRG −/−), oligodendrocytes fail to develop. Addition of recombinant neuregulin to spinal cord explants from NRG −/− mice rescues oligodendrocyte development. In wild-type spinal cord explants, inhibitors of neuregulin mimic the inhibition of oligodendrocyte development that occurs in NRG −/− explants. In embryonic mouse spinal cord, neuregulins are present in motor neurons and the ventral ventricular zone where they likely exert their influence on early oligodendrocyte precursor cells.     

检测Addison病患者血浆极长链脂肪酸的重要意义

目的对临床疑诊和曾经诊断为Addison病的患者进行血浆极长链脂肪酸（VLCFA）浓度的检测,以便发现其中的X-连锁肾上腺脑白质营养不良（X-ALD）患者。方法应用气相色谱法检测36例Addison病患者的血浆VLCFA,包括C26：0含量,C26．0／C22：0和C24．0／C22：0比值3项指标,并对结果总结分析。结果36例患者中有6例的VLCFA异常增高,可确诊为X-ALD。结论对Addison病患者,尤其是年轻男性患者,应该及早检测血浆VLCFA,减少X-ALD的误诊。     

Hexacosanoic and docosanoic acids plasma levels in patients with cerebral childhood and asymptomatic X-linked adrenoleukodystrophy: Lorenzo’s oil effect

X-linked adrenoleukodystrophy (X-ALD) is an inherited disorder of peroxisomal metabolism, biochemically characterized by deficient β-oxidation of saturated very long chain fatty acids (VLCFA). The consequent accumulation of these fatty acids in different tissues and in biological fluids is associated with a progressive central and peripheral demyelination, as well as with adrenocortical insufficiency and hypogonadism. Seven variants of this disease have been described, being cerebral childhood the most frequent. The recommended therapy consists of the use of the glyceroltrioleate/glyceroltrierucate mixture known as Lorenzo’s Oil (LO), combined with a VLCFA-poor diet, but only in asymptomatic patients will this treatment prevent the progression of the symptomatology. In the present study we evaluated the biochemical course of patients with cerebral childhood (CCER) and asymptomatic clinical forms of X-ALD treated with LO associated with a VLCFA-restricted diet. We observed that hexacosanoic acid plasma concentrations and hexacosanoic/docosanoic ratio were significantly reduced in CCER patients during treatment when compared with diagnosis. Hexacosanoic acid plasma level was significantly reduced when compared with that at diagnosis and achieved the normal levels only in asymptomatic patients under LO treatment. In asymptomatic patients the magnitude of hexacosanoic acid decrease was higher than that of the CCER patients. These results show the good biochemical response of LO treatment in asymptomatic X-ALD patients. It is possible to suppose that this could be correlated with the prevention of the appearance of neurological signals in this group of patients treated with LO.     

Effect of lovastatin on serum lipid profile in the treatment of dyslipoproteinaemia in uraemic patients on continuous ambulatory peritoneal dialysis

Background: Dyslipoproteinaemia is an important risk factor for cardiovascular disease in uraemic patients on continuous ambulatory peritoneal dialysis (CAPD). Lovastatin is an HMG Coenzyme A reductase inhibitor which is useful in treating non-uraemic patients with hypercholesterolaemia.
Aims: We conducted a single blind cross-over study versus placebo in 10 CAPD patients to examine the effect of lovastatin (20–40 mg) on the serum lipid profile and its safety in uraemic patients.
Methods: Treatment phases were of eight weeks' duration. Each four weeks' measurements were made of serum total cholesterol (TC), triglyceride (TG), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), VLDL-cholesterol (VLDL-C), Apolipoprotein Al & B (Apo Al & Apo B) and Lipoprotein (a). After eight weeks, lovastatin significantly reduced TC by 29% from 6.7 ± 0.3 (mean±S.E.M.) to 4.8±0.1 mmol/L, LDL-C by 41% from 4.6±0.3 to 2.7±0.1 mmol/L and Apo B by 32% from 116±7 to 78±3 mg/dl (p<0.01). HDL-C increased by 8% froml.2±0.1 to 1.3 ±0.2 mmol/L after eight weeks' therapy (p<0.05). TG decreased by 18% from 1.9 ±0.4 to 1.6 ±0.3 mmol/L (p< 0.05). There was no significant difference in changes of other lipid profiles between placebo and drug. No adverse effects of the drug were noted during treatment and the liver function and muscle enzymes were not significantly altered by either drug therapy or placebo.
Results: Lovastatin appears to be a safe and useful drug in effectively treating dyslipoproteinaemia in CAPD patients. (Aust NZ J Med 1993; 23: 252–257.)     

Testicular function in type II hyperlipoproteinemic patients treated with lovastatin (mevinolin) or neomycin

Steroid synthesis requires cholesterol derived from de novo synthesis or plasma lipoproteins. Low density lipoproteins appear to be the major contributor of cholesterol for steroid synthesis in man. Patients with disorders of low density lipoproteins or the low density lipoprotein receptor have reduced cortisol production in response to ACTH. Therapeutic agents designed to lower plasma cholesterol could, therefore, adversely affect steroid hormone production. Lovastatin (mevinolin) is a new hypolipidemic agent which blocks cholesterol synthesis by competitive inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase. In beagle dogs, lovastatin at 40-180 times the clinically effective dose in man, has been associated with an increase in spontaneous testicular atrophy. Accordingly, the effect of lovastatin on testicular function and lipoprotein levels was studied in 16 hyperlipidemic men in a randomized, double blind, cross-over study with another hypolipidemic agent, neomycin. Serum testosterone, PRL, LH, and FSH; LHRH-stimulated LH and FSH concentrations; and testicular size were measured, and semen analyses were made. We found no evidence that lovastatin had adverse effects on testicular function despite significant alterations in plasma lipoprotein concentrations.     

Resistance to erucic acid as a selectable marker for peroxisomal activity: Isolation of revertants of an infantile Refsum disease cell line

Summary A system based on the ability of cells to oxidize very long-chain fatty acids (VLCFA) was developed to selectin vitro normal human fibroblasts from fibroblasts of patients suffering from peroxisomal disorders with multienzymatic deficiencies: Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum disease (IRD). Cells treated with various concentrations of erucic acid (C_{22:1 n-9}) revealed an enhanced toxicity of this fatty acid for the fibroblasts of patients compared with normal cells. This differential toxicity is correlated with variable accumulations of C_{22:1 n-9} and the absence of -oxidation products in the mutants.Revertants from clonal IRD cell lines were isolated in the selective medium at frequencies ranging from 3×10^–7 to 4×10^–6 depending on the line. After six weeks of growth in the absence of selective pressure, the variants exhibited a resistance level to C_{22:1 n-9} identical to that of normal cells. Furthermore, -oxidation of VLCFA is re-established in these selected cells as well as dihydroxyacetone phosphate acyltransferase activity. Immunoblot experiments also demonstrated a restored pattern of acyl-CoA oxidase molecular forms. Last, immunofluorescence studies revealed the presence of cytoplasmic structures that were absent in the original IRD cells. Thus, both the deficiencies in metabolic pathways and paucity of the organelle are at least partially corrected in the selected clones.     

Regulation of low density lipoprotein apoprotein B metabolism by lovastatin and cholestyramine in miniature pigs: effects on LDL composition and synthesis of LDL subfractions

A major factor in the regulation of low density lipoprotein (LDL) apoprotein B (apo B) concentrations in miniature pigs is the direct synthesis of LDL apo B. LDL apo B derived from plasma very low density lipoproteins (VLDL) accounts for only 20% to 30% of total LDL synthesis. Treatment with lovastatin and cholestyramine can inhibit the direct synthesis pathway in this species, thereby lowering LDL apo B concentrations. The present study was carried out to determine if lovastatin alone was as effective as in combination with cholestyramine. The possibility that the direct synthesis pathway was confined to a specific subclass of LDL and the effect of lovastatin and cholestyramine on the metabolism of LDL subfractions were also investigated. Homologous 125I-VLDL and 131I-LDL were injected into miniature pigs during a control period and again following 18 days of treatment with lovastatin (1.2 mg/kg/d, n = 4) or in combination with cholestyramine (1.0 g/kg/d, n = 4). Kinetic analysis of apo B specific activity curves following lovastatin treatment indicated that LDL apo B pool size was decreased by 25% (P less than .025), which was due entirely to a 70% (P less than .025) decrease in the direct synthesis of LDL apo B, since VLDL-derived apo B, and LDL fractional catabolic rate (FCR) were not affected. Parameters of VLDL apo B metabolism were not affected. Lovastatin in combination with cholestyramine was more effective than lovastatin alone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Post-transplant hyperlipidaemia: low-dose lovastatin lowers atherogenic lipids with without plasma accumulation of lovastatin

Abstract. Gullestad L, Nordal K, Forfang K, Ihlen H, Hostmark A, Berg KJ, Cheng H, Schwartz MS, Geiran 0, Simonsen S (Rikshospitalet University Hospital and University of Oslo, Oslo, Norway, and Merck Research Laboratories, West Point, PA, USA). Post-transplant hyperlipidaemia: low-dose lovastatin lowers atherogenic lipids without plasma ac-cumulation of lovastatin. 1 Intern Med 1997; 242: 483-490. Objectives: The purpose of the present study was twofold. First, to determine the frequency of hyperlipidaemia after heart transplantation (Tx) in relation to values obtained before Tx. Secondly, to examine the effect of low-dose lovastatin on possible antiatherogenic mechanisms and test the hypothesis that the side-effects are dose-dependent. Subjects and design: Retrospective study of the frequency of hyperlipidaemia disturbances in heart transplant patients. In addition, in a prospective study, the safety and efficacy of incremental study, the safety and efficacy of incremental studied, with measurements of its plasma concentration in 24 cyclosporin A treated heart (n = 14) and kidney (n = 10) recipients with total cholesterol >7.5 mmol L-I. Results: Cholesterol increased markedly after heart transplantation from a pretransplant value of 5.3 (5.0.5.6) mmol L-‘ to 6.7 (6.4.7.0) mmol L -’ after 1 year and then remained constant, but this increase was largely due to a ‘normalization’ since cholesterol decreased significantly during increasing heart failure before transplantation. Treatment with lovastatin decreased total cholesterol by 19% (P < 0.00l), primarily by an effect on IBL cholesterol. HDL cholesterol increased by 15% (P < 0.05), whereas triglycerides remained unchanged. Lovastatin also caused a significant reduction in apolipoprotein B of 16% and lipid peroxidation of 40%. whereas apolipoprotein A-I, fibperoxidation of 40%. whereas apolipoprotein A-I, fibcentration of lovastatin was significantly higher in transplant recipients compared with controls, but there was no accumulation during incremental dosing of lovastatin. The drug was well tolerated without significant symptoms or evidence of myopathy. Conclusions: Hyperlipidaemia is common after cardiac transplantation. Treatment with low dose lovastatin is well tolerated and has a favourable effect on atherogenic lipids.     

Direct immunogold labeling of aquaporin-4 in square arrays of astrocyte and ependymocyte plasma membranes in rat brain and spinal cord

Aquaporin (AQP) water channels are abundant in the brain and spinal cord, where AQP1 and AQP4 are believed to play major roles in water metabolism and osmoregulation. Immunocytochemical analysis of the brain recently revealed that AQP4 has a highly polarized distribution, with marked expression in astrocyte end-feet that surround capillaries and form the glia limitans; however, the structural organization of AQP4 has remained unknown. In freeze-fracture replicas, astrocyte end-feet contain abundant square arrays of intramembrane particles that parallel the distribution of AQP4. To determine whether astrocyte and ependymocyte square arrays contain AQP4, we employed immunogold labeling of SDS-washed freeze-fracture replicas and stereoscopic confirmation of tissue binding. Antibodies to AQP4 directly labeled ≈33% of square arrays in astrocyte and ependymocyte plasma membranes in rat brain and spinal cord. Overall, 84% of labels were present beneath square arrays; 11% were beneath particle clusters that resembled square arrays that had been altered during fixation or cleaving; and 5% were beneath the much larger areas of glial plasma membrane that were devoid of square arrays. Based on this evidence that AQP4 is concentrated in glial square arrays, freeze-fracture methods may now provide biophysical insights regarding neuropathological states in which abnormal fluid shifts are accompanied by alterations in the aggregation state or the molecular architecture of square arrays.     

Effects of magnetic sacral root stimulation on anorectal pressure and volume

PURPOSE: Electrical sacral root stimulation induces defecation in spinal cord injury patients and is currently under examination as a new therapy for fecal incontinence. In contrast to electrical stimulation, magnetic stimulation is noninvasive. To gain more insight into the mechanism of action of sacral root stimulation, we studied the effects of magnetic sacral root stimulation on anorectal pressure and volume in both fecal incontinence and spinal cord injury patients. METHODS: Three groups were examined: 14 healthy volunteers, 18 fecal incontinence patients, and 14 spinal cord injury patients. Repetitive magnetic sacral root stimulation was performed bilaterally using bursts of five seconds at 5 Hz. Anal and rectal pressure changes and rectal volume changes were measured. RESULTS: An increase in anal pressure was seen in 100 percent of the control subjects, in 86 percent of the spinal cord injury patients, and in 73 percent of the fecal incontinence patients (P=0.03). The overall median pressure rise after right-sided and left-sided stimulation was 12 (interquartile range, 8–18.5) and 13 (interquartile range, 6–18) mmHg at the mid anal level. A decrease in rectal volume was provoked in 72 percent of the control subjects, in 79 percent of the spinal cord injury patients, and in 50 percent of the fecal incontinence patients. Overall median volume changes after right-sided and left-sided stimulation were 10 (range, 5–22) and 9 (range, 5–21) percent from baseline volume. An increase in rectal pressure could be measured in 56 percent of the control subjects, 77 percent of the fecal incontinence patients, and 43 percent of the spinal cord injury patients. Median pressure rises after right-sided and left-sided stimulation were 5 (range, 3–12) and 5 (range, 3–5) mmHg. CONCLUSIONS: Magnetic sacral root stimulation produces an increase in anal and rectal pressure and a decrease in rectal volume in healthy subjects and patients with fecal incontinence or a spinal cord injury.Read at the XVIII Biennial Congress of The International Society of University Colon and Rectal Surgeons, São Paulo, Brazil, July 23 to 27, 2000.     

Adrenoleukodystrophy

X-linked adrenoleukodystrophy (ALD) is a disorder of very long chain fatty acid (VLCFA) metabolism that can be diagnosed by demonstrating increased levels of VLCFA in plasma and, prenatally, by similar assays in cultured amniocytes or chorionic vilus samples. ALD causes Addison disease frequently in men and occasionally in women. Prompt diagnosis is important for genetic counseling and for the institution of therapies aimed to prevent or ameliorate the progressive neurologic disability that often is associated with this illness.