Rabindra Tirouvanziam

A randomized controlled pilot trial of oral N-acetylcysteine in children with autism.

BACKGROUNDnAn imbalance in the excitatory/inhibitory systems with abnormalities in the glutamatergic pathways has been implicated in the pathophysiology of autism. Furthermore, chronic redox imbalance was also recently linked to this disorder. The goal of this pilot study was to assess the feasibility of using oral N-acetylcysteine (NAC), a glutamatergic modulator and an antioxidant, in the treatment of behavioral disturbance in children with autism.nnnMETHODSnThis was a 12-week, double-blind, randomized, placebo-controlled study of NAC in children with autistic disorder. Subjects randomized to NAC were initiated at 900 mg daily for 4 weeks, then 900 mg twice daily for 4 weeks and 900 mg three times daily for 4 weeks. The primary behavioral measure (Aberrant Behavior Checklist [ABC] irritability subscale) and safety measures were performed at baseline and 4, 8, and 12 weeks. Secondary measures included the ABC stereotypy subscale, Repetitive Behavior Scale-Revised, and Social Responsiveness Scale.nnnRESULTSnThirty-three subjects (31 male subjects, 2 female subjects; aged 3.2-10.7 years) were randomized in the study. Follow-up data was available on 14 subjects in the NAC group and 15 in the placebo group. Oral NAC was well tolerated with limited side effects. Compared with placebo, NAC resulted in significant improvements on ABC irritability subscale (F = 6.80; p < .001; d = .96).nnnCONCLUSIONSnData from this pilot investigation support the potential usefulness of NAC for treating irritability in children with autistic disorder. Large randomized controlled investigations are warranted.

Metabolic Adaptation of Neutrophils in Cystic Fibrosis Airways Involves Distinct Shifts in Nutrient Transporter Expression

Inflammatory conditions can profoundly alter human neutrophils, a leukocyte subset generally viewed as terminally differentiated and catabolic. In cystic fibrosis (CF) patients, neutrophils recruited to CF airways show active exocytosis and sustained phosphorylation of prosurvival, metabolic pathways. Because the CF airway lumen is also characterized by high levels of free glucose and amino acids, we compared surface expression of Glut1 (glucose) and ASCT2 (neutral amino acids) transporters, as well as that of PiT1 and PiT2 (inorganic phosphate transporters), in blood and airway neutrophils, using specific retroviral envelope-derived ligands. Neither nutrient transporter expression nor glucose uptake was altered on blood neutrophils from CF patients compared with healthy controls. Notably, however, airway neutrophils of CF patients had higher levels of PiT1 and Glut1 and increased glucose uptake compared with their blood counterparts. Based on primary granule exocytosis and scatter profiles, CF airway neutrophils could be divided into two subsets, with one of the subsets characterized by more salient increases in Glut1, ASCT2, PiT1, and PiT2 expression. Moreover, in vitro exocytosis assays of blood neutrophils suggest that surface nutrient transporter expression is not directly associated with primary (or secondary) granule exocytosis. Although expression of nutrient transporters on CF blood or airway neutrophils was not altered by genotype, age, gender, or Pseudomonas aeruginosa infection, oral steroid treatment decreased Glut1 and PiT2 levels in blood neutrophils. Thus, neutrophils recruited from blood into the CF airway lumen display augmented cell surface nutrient transporter expression and glucose uptake, consistent with metabolic adaptation.

Distinct Plasma Profile of Polar Neutral Amino Acids, Leucine, and Glutamate in Children with Autism Spectrum Disorders

The goal of this investigation was to examine plasma amino acid (AA) levels in children with Autism Spectrum Disorders (ASD, Nxa0=xa027) and neuro-typically developing controls (Nxa0=xa020). We observed reduced plasma levels of most polar neutral AA and leucine in children with ASD. This AA profile conferred significant post hoc power for discriminating children with ASD from healthy children. Furthermore, statistical correlations suggested the lack of a typical decrease of glutamate and aspartate with age, and a non-typical increase of isoleucine and lysine with age in the ASD group. Findings from this limited prospective study warrant further examination of plasma AA levels in larger cross-sectional and longitudinal cohorts to adequately assess for relationships with developmental and clinical features of ASD.

PET Imaging of Stroke-Induced Neuroinflammation in Mice Using [18F]PBR06

PurposeThe purpose of this study is to evaluate the 18xa0kDa translocator protein (TSPO) radioligand [18F]N-fluoroacetyl-N-(2,5-dimethoxybenzyl)-2-phenoxyaniline ([18F]PBR06) as a positron emission tomography (PET) imaging biomarker of stroke-induced neuroinflammation in a rodent model.ProceduresStroke was induced by transient middle cerebral artery occlusion in Balb/c mice. Dynamic PET/CT imaging with displacement and preblocking using PK111195 was performed 3xa0days later. PET data were correlated with immunohistochemistry (IHC) for the activated microglial markers TSPO and CD68 and with autoradiography.Results[18F]PBR06 accumulation peaked within the first 5xa0min postinjection, then decreased gradually, remaining significantly higher in infarct compared to noninfarct regions. Displacement or preblocking with PK11195 eliminated the difference in [18F]PBR06 uptake between infarct and noninfarct regions. Autoradiography and IHC correlated well spatially with uptake on PET.Conclusions[18F]PBR06 PET specifically images TSPO in microglial neuroinflammation in a mouse model of stroke and shows promise for imaging and monitoring microglial activation/neuroinflammation in other disease models.

Bioelectric properties of human cystic fibrosis and non-cystic fibrosis fetal tracheal xenografts in SCID mice

We measured, the bioelectric properties of 14 cystic fibrosis (CF) and 33 non-CF human fetal tracheal xenografts in severe combined immunodeficiency (SCID) mice. All xenografts exhibited a mature airway-type epithelium irrespective of their gestational age, duration of engraftment, and genotype. The in vivo potential difference and the in vitro baseline short-circuit current (Isc) were significantly higher in non-CF than in CF xenografts. In non-CF xenografts, sequential addition of amiloride, forskolin, and ATP resulted in a 39.4% decrease, a 24.1% increase, and a 43.6% increase in Isc, respectively. In CF xenografts, forskolin had no significant effect on Isc, whereas amiloride- and ATP-induced changes in Isc were proportionally higher than in non-CF xenografts (-60.0 and +68.8%, respectively). These results indicate that the bioelectric properties of non-CF xenografts are similar to those of postnatal airways and that CF xenografts exhibit lower baseline electrogenic activity than non-CF xenografts but similar regulation of ion transport processes to postnatal CF airways. This model of mature human fetal tracheal mucosa may help gain insight into early CF airway pathogenesis.

Modulation of mTOR Effector Phosphoproteins in Blood Basophils from Allergic Patients

The mammalian target of rapamycin (mTOR) pathway contributes to various immunoinflammatory processes. Yet, its potential involvement in basophil responses in allergy remains unclear. In this pilot study, we quantified two key mTOR effector phosphoproteins, the eukaryotic initiation factor 4E (peIF4E) and S6 ribosomal protein (pS6rp), in blood basophils from nut allergy patients (NA, Nu2009=u200916) and healthy controls (HC, Nu2009=u200913). Without stimulation in vitro, basophil peIF4E levels were higher in NA than HC subjects (Pu2009=u20090.014). Stimulation with nut (offending) but not chicken / rice (non-offending) extract increased basophil peIF4E and pS6rp levels (+32%, Pu2009=u20090.018, and +98%, Pu2009=u20090.0026, respectively) in NA but not HC subjects, concomitant with increased surface levels of CD203c and CD63, both known to reflect basophil activation. Pre-treatment with the mTOR inhibitor rapamycin decreased pS6rp and CD203c responses in nut extract-stimulated basophils in NA subjects. Thus, basophil responses to offending allergens are associated with modulation of mTOR effector phosphoproteins.

Cysteine/Glutathione Deficiency: A Significant and Treatable Corollary of Disease

Glutathione (GSH) deficiency may play a pivotal role in a variety of apparently unrelated clinical conditions and diseases. Orally administered N-acetylcysteine (NAC), which replenishes the cysteine required for GSH synthesis, has been tested in a large number of randomized placebo-controlled trials involving these diseases and conditions. This chapter focused on developing a base of evidence suggesting that NAC administration improves disease by increasing cysteine and/or GSH in a variety of diseases, thereby implying a significant role for GSH deficiency in the clinical basis of many diseases. To develop this base of evidence, we systematically selected studies which considered the hypothesis that the therapeutic efficacy for NAC is an indication that cysteine and/or GSH deficiency is a pathophysiological part of the diseases studied. In this manner we focus this chapter on explaining the biological mechanisms of NAC therapy in a wide variety of disorders and demonstrate its ubiquitous role in improving disease that involves disrupted GSH and/or cysteine metabolism. Electronic supplementary material The online version of this article (10.1007/978-981-10-5311-5_20) contains supplementary material, which is available to authorized users.

Pharmacology, Formulations, and Adverse Effects

Besides understanding the effectiveness of N-acetylcysteine (NAC) for the treatment of disease and its effect on physiological systems, other considerations of NAC are important, including the pharmacology, formulations, and adverse effects of NAC. This chapter will review these important aspects of NAC. Few published trials have examined the pharmacokinetics of NAC. Maximum plasma concentration increases with oral NAC doses (up to 1200 mg has been studied), particularly with sustained-release formulations. Oral and intravenous NAC seems to have similar half-lives (around 6 h). The pharmacokinetics of NAC is altered by chronic liver and renal disease as well as exercise. Clearance is altered in the neonatal period and with dialysis. NAC does not appear to alter the concentration of several common antibiotics, including amoxicillin, cefadroxil, cefpodoxime, doxycycline, and erythromycin. There are many nonprescription forms of NAC that are not regulated, particularly in the United States, which can easily oxidize in its dimeric form (“di-NAC”) which can result in opposite physiological effects. There are several formulations that follow Good Manufacturing Practice standards that are believed to be more stable.