Porphyrinuria in childhood autistic disorder is not associated with urinary creatinine deficiency

Abnormal Porphyrin Metabolism in Autism Spectrum Disorder and Therapeutic Implications

Autism spectrum disorder (ASD) is a mosaic of neurodevelopmental conditions composed of early-onset social interaction and communication deficits, along with repetitive and/or restricted patterns of activities, behavior, and interests. ASD affects around 1% of children worldwide, with a male predominance. Energy, porphyrin, and neurotransmitter homeostasis are the key metabolic pathways affected by heavy metal exposure, potentially implicated in the pathogenesis of ASD. Exposure to heavy metals can lead to an altered porphyrin metabolism due to enzyme inhibition by heavy metals. Heavy metal exposure, inborn genetic susceptibility, and abnormal thiol and selenol metabolism may play a significant role in the urinary porphyrin profile anomalies observed in ASD. Altered porphyrin metabolism in ASD may also be associated with, vitamin B6 deficiency, hyperoxalemia, hyperhomocysteinemia, and hypomagnesemia. The present review considers the abnormal porphyrin metabolism in ASD in relation to the potential pathogenic mechanism and discusses the possible metabolic therapies such as vitamins, minerals, cofactors, and antioxidants that need to be explored in future research. Such targeted therapeutic therapies would bring about favorable outcomes such as improvements in core and co-occurring symptoms.

The Novel Potential Therapeutic Utility of Montelukast in Alleviating Autistic Behavior Induced by Early Postnatal Administration of Thimerosal in Mice

BACKGROUND AND AIM: Thimerosal (THIM) is a mercury-containing preservative widely used in many biological and medical products including many vaccines. It has been accused of being a possible etiological factor for some neurodevelopmental disorders such as autistic spectrum disorders (ASDs). In our study, the potential therapeutic effect of montelukast, a leukotriene receptor antagonist used to treat seasonal allergies and asthma, on THIM mice model (ASDs model) was examined.

METHODOLOGY

Newborn mice were randomly distributed into three groups: (Group 1) Control (Cont.) group received saline injections. (Group 2) THIM-treated (THIM) group received THIM intramuscular (IM) at a dose of 3000 μg Hg/kg on postnatal days 7, 9, 11, and 15. (Group 3) Montelukast-treated (Monte) group received THIM followed by montelukast sodium (10 mg/kg/day) intraperitoneal (IP) for 3 weeks. Mice were evaluated for growth development, social interactions, anxiety, locomotor activity, and cognitive function. Brain histopathology, alpha 7 nicotinic acetylcholine receptors (α7nAChRs), nuclear factor kappa B p65 (NF-κB p65), apoptotic factor (Bax), and brain injury markers were evaluated as well.

RESULTS

THIIM significantly impaired social activity and growth development. Montelukast mitigated THIM-induced social deficit probably through α7nAChRs upregulation, NF-κB p65, Bax, and brain injury markers downregulation, thus suppressing THIM-induced neuronal toxicity and inflammation.

CONCLUSION

Neonatal exposure to THIM can induce growth retardation and abnormal social interactions similar to those observed in ASDs. Some of these abnormalities could be ameliorated by montelukast via upregulation of α7nAChRs that inhibited NF-κB activation and significant suppression of neuronal injury and the associated apoptosis.

Protective role of alpha-lipoic acid in impairments of social and stereotyped behaviors induced by early postnatal administration of thimerosal in male rat

Aim Thimerosal, a mercury-containing preservative has been widely used in a number of biological and drug products, including many vaccines, and has been studied as a possible etiological factor for some neurodevelopmental disabilities. Here, the protective effects of Alpha Lipoic Acid (ALA), an organosulfur compound derived from Octanoic Acid, on Thimerosal-induced behavioral abnormalities in rat were examined.

METHODS

108 male Wistar rats were divided into three cohorts and treated as follows: 1) Thimerosal at different doses (30, 300, or 3000 μg Hg/kg) in four i.m. injections on 7, 9, 11, 15postnatal days. 2) ALA (at doses of 5, 10 and 20 mg/kg), following the same order; 3) single dose of Thimerosal (3000 μg Hg/kg) plus ALA at different doses (5, 10 or 20 mg/kg), by the previously described method. A saline treated control group and a ALA vehicle control (0.1% NaOH) were also included. At 5 and 8 weeks after birth, rats were evaluated with behavioral tests, to assess locomotor activity, social interactions and stereotyped behaviors, respectively.

RESULTS

The data showed that Thimerosal at all doses (30, 300 and 3000 μg Hg/kg) significantly impacted locomotor activity. Thimerosal at doses of 300 and 3000 but not 30 μg Hg/kg impaired social and stereotyped behaviors. In contrast, ALA (at doses of 5, 10 and 20 mg/kg) did not alter behaviors by itself, at doses of 20 mg/kg, it reduced social interaction deficits induced by the highest dose of Thimerosal (3000 μg Hg/kg). Moreover, ALA, at all doses prevented the adverse effects of Thimerosal on stereotyped behaviors.

CONCLUSIONS

the results of this preclinical study, consistent with previous studies on mice and rats, reveals that neonatal dose-dependent exposure to Thimerosal mimicking the childhood vaccine schedule can induce abnormal social interactions and stereotyped behaviors similar to those observed in neurodevelopmental disorders such as autism, and, for the first time, revealed that these abnormalities may be ameliorated by ALA. This indicates that ALA may protect against mercurial-induced abnormal behaviors.

A review of candidate urinary biomarkers for autism spectrum disorder

CONTEXT

Autism is a complex, heterogeneous neurodevelopmental condition with a strong genetic component potentially impacted by various environmental factors influencing susceptibility. There are no reliable laboratory tests available to confirm an autism diagnosis.

OBJECTIVE

To examine the published literature and identify putative urinary biomarkers of autism.

METHODS

A comprehensive literature search was conducted using electronic bibliographic databases.

RESULTS

Putative autism biomarkers were identified that could be categorized according to the key theories that exist regarding the etiology of autism: gastrointestinal factors, immune dysregulation, heavy metal toxicity, neurotransmitter abnormalities, and oxidative stress.

CONCLUSION

There is scope for specific urinary biomarkers to be useful for identification of autistic metabolic phenotypes.

Theoretical aspects of autism: causes--a review

Autism, a member of the pervasive developmental disorders (PDDs), has been increasing dramatically since its description by Leo Kanner in 1943. First estimated to occur in 4 to 5 per 10,000 children, the incidence of autism is now 1 per 110 in the United States, and 1 per 64 in the United Kingdom, with similar incidences throughout the world. Searching information from 1943 to the present in PubMed and Ovid Medline databases, this review summarizes results that correlate the timing of changes in incidence with environmental changes. Autism could result from more than one cause, with different manifestations in different individuals that share common symptoms. Documented causes of autism include genetic mutations and/or deletions, viral infections, and encephalitis following vaccination. Therefore, autism is the result of genetic defects and/or inflammation of the brain. The inflammation could be caused by a defective placenta, immature blood-brain barrier, the immune response of the mother to infection while pregnant, a premature birth, encephalitis in the child after birth, or a toxic environment.

Contributions of the environment and environmentally vulnerable physiology to autism spectrum disorders

PURPOSE OF REVIEW

This review presents a rationale and evidence for contributions of environmental influences and environmentally vulnerable physiology to autism spectrum disorders (ASDs).

RECENT FINDINGS

Recent studies suggest a substantial increase in ASD prevalence above earlier Centers for Disease Control figures of one in 150, only partly explicable by data artifacts, underscoring the possibility of environmental contributors to increased prevalence. Some gene variants in ASD confer altered vulnerability to environmental stressors and exposures. De-novo mutations and advanced parental age as a risk factor for ASD also suggest a role for environment. Systemic and central nervous system pathophysiology, including oxidative stress, neuroinflammation, and mitochondrial dysfunction can be consistent with a role for environmental influence (e.g. from air pollution, organophosphates, heavy metals) in ASD, and some of the underlying biochemical disturbances (such as abnormalities in glutathione, a critical antioxidant and detoxifier) can be reversed by targeted nutritional interventions. Dietary factors and food contaminants may contribute risk. Improvement and loss of diagnosis in some with ASD suggest brain circuitry amenable to environmental modulation.

SUMMARY

Prevalence, genetic, exposure, and pathophysiological evidence all suggest a role for environmental factors in the inception and lifelong modulation of ASD. This supports the need for seeking targets for early and ongoing medical prevention and treatment of ASD.

A prospective blinded evaluation of urinary porphyrins verses the clinical severity of autism spectrum disorders

A prospective, blinded study evaluated the relationship between autism spectrum disorder (ASD) severity measured by Childhood Autism Rating Scale (CARS) scores and urinary porphyrins among a cohort of participants (n = 26). LabCorp (CLIA-approved) tested for uroporphyrins, heptacarboxylporphyrins, hexacarboxylporphyrins, pentacarboxylporphyrins, coproporphyrin (cP) I, and cP III levels. Participants with severe ASD had significantly increased cP I, cP III, and total cP levels in comparison to participants with mild ASD. A significant correlation was observed between increasing cP levels and CARS scores. Significant correlations were also noted for comparative urinary porphyrin testing between LabCorp and the Laboratoire Philippe Auguste (ISO-approved) for total cP. Finally, total cP measured at LabCorp was found to significantly correlate with precoproporphryin (a specific porphyrin marker for mercury toxicity) measured at the Laboratoire Philippe Auguste. Since urinary porphyrin testing is clinically available, relatively inexpensive, and noninvasive, it may be used to help suggest whether heavy metal toxicity is associated with ASD.