The SNP rs2298383 Reduces ADORA2A Gene Transcription and Positively Associates with Cytokine Production by Peripheral Blood Mononuclear Cells in Patients with Multiple Chemical Sensitivity

Systemic inflammation and immune activation are striking features of multiple chemical sensitivity (MCS). The rs2298383 SNP of ADORA2A gene, coding for adenosine receptor type 2A (A2AR), has been involved in aberrant immune activation. Here we aimed to assess the prevalence of this SNP in 279 MCS patients and 238 healthy subjects, and its influence on ADORA2A, IFNG and IL4 transcript amounts in peripheral blood mononuclear cells of randomly selected patients (n = 70) and controls (n = 66) having different ADORA2A genotypes. The ADORA2A rs2298383 TT mutated genotype, significantly more frequent in MCS patients than in controls, was associated with a three-fold increased risk for MCS (O.R. = 2.86; C.I. 95% 1.99–4.12, p < 0.0001), while the CT genotype, highly prevalent among controls, resulted to be protective (O.R. = 0.33; C.I. 95% 0.224–0.475, p < 0.0001). Notably, ADORA2A mRNA levels were significantly lower, while IFNG, but not IL4, mRNA levels were significantly higher in TT MCS patients compared with controls. A significant negative correlation was found between ADORA2A and both IFNG and IL4, while a significant positive correlation was found between IFNG and IL4. These findings suggest that A2AR defective signaling may play a relevant role in PBMC shift towards a pro-inflammatory phenotype in MCS patients.

Olfactory-Related Quality of Life in Multiple Chemical Sensitivity: A Genetic-Acquired Factors Model

Genetic polymorphisms as well as environmental exposures to chemical compounds, iatrogenic, psychological, and physical trauma may play a pathophysiological role in multiple chemical sensitivity (MCS) olfactory complaints, given that xenobiotic metabolism is influenced by sequence variations in genes of metabolizing enzymes. Thus, the aim of the present study was to depict-by means of multiple regression analysis-how different genetic conditions, grouped according to their function as well as clinical background and environmental exposure may interfere with those olfactory complaints referred by MCS patients. Therefore, MCS patients after gene polymorphism sequencing, the olfactory-related quality of life score-calculated by means of the Questionnaire of Olfactory Disorder in forty-six MCS patients-have been found to significantly rely on the phase I and II enzymes score and exposure to previous compounds and surgical treatments. The present work-implementing for the first time a genetic-acquired factors model on a regression analysis-further reinforces those theories, positing MCS as a complex, multifactorial, disease in which the genetic risk related to phase I and II enzymes involved in xenobiotic detoxification, olfactory, and neurodegenerative diseases play a necessary, but probably not sufficient role, along the pathophysiological route of the disease.

Gene expression profiling in persons with multiple chemical sensitivity before and after a controlled n-butanol exposure session

OBJECTIVES

To investigate the pathophysiological pathways leading to symptoms elicitation in multiple chemical sensitivity (MCS) by comparing gene expression in MCS participants and healthy controls before and after a chemical exposure optimised to cause symptoms among MCS participants.The first hypothesis was that unexposed and symptom-free MCS participants have similar gene expression patterns to controls and a second hypothesis that MCS participants can be separated from controls based on differential gene expression upon a controlled n-butanol exposure.

DESIGN

Participants were exposed to 3.7 ppm n-butanol while seated in a windowed exposure chamber for 60 min. A total of 26 genes involved in biochemical pathways found in the literature have been proposed to play a role in the pathogenesis of MCS and other functional somatic syndromes were selected. Expression levels were compared between MCS and controls before, within 15 min after being exposed to and 4 hours after the exposure.

SETTINGS

Participants suffering from MCS and healthy controls were recruited through advertisement at public places and in a local newspaper.

PARTICIPANTS

36 participants who considered themselves sensitive were prescreened for eligibility. 18 sensitive persons fulfilling the criteria for MCS were enrolled together with 18 healthy controls.

OUTCOME MEASURES

17 genes showed sufficient transcriptional level for analysis. Group comparisons were conducted for each gene at the 3 times points and for the computed area under the curve (AUC) expression levels.

RESULTS

MCS participants and controls displayed similar gene expression levels both at baseline and after the exposure and the computed AUC values were likewise comparable between the 2 groups. The intragroup variation in expression levels among MCS participants was noticeably greater than the controls.

CONCLUSIONS

MCS participants and controls have similar gene expression levels at baseline and it was not possible to separate MCS participants from controls based on gene expression measured after the exposure.

Assessment of glutathione peroxidase-1 polymorphisms, oxidative stress and DNA damage in sensitivity-related illnesses

AIMS

Oxidative stress increase is a key event for development of sensitivity-related illnesses (SRIs). The aim of this work was to evaluate the influence of a genetic variant in the antioxidant enzyme glutathione peroxidase (GPx1) on oxidative stress development in SRIs.

MAIN METHODS

GPx1 rs1800668 genotype, as well as glutathione, ubiquinone, and DNA damage were assessed in 34 SRI patients and 36 healthy subjects.

KEY FINDINGS

Total glutathione, reduced/oxidized glutathione, and ubiquinone were significantly decreased in cases compared with controls, while DNA fragmentation was significantly increased in patients. However, these differences were not associated to GPx1 genetic background.

SIGNIFICANCE

GPx1 rs1800668 polymorphism does not play a major role in SRI-related oxidative stress development.

Evaluation of genetic polymorphisms in patients with multiple chemical sensitivity

Objective

Multiple chemical sensitivity (MCS) is a chronic medical condition characterized by symptoms that the affect an individual’s response to low-level chemical exposure. In this study, we identified a chemical sensitive population (CSP) and investigated the effect of genetic polymorphisms on their risk of chemical sensitivity.

Methods

A quick environment exposure sensitivity (QEESI) questionnaire was used to survey 324 Japanese male workers whose DNA samples had been collected and stored. The following genes, which encode enzymes affecting the metabolic activation of a large number of xenobiotic compounds, were selected and analyzed in order to determine their influence on genetic predisposition to CSP: cytochrome P450 (CYP) 2E1, N-acetyl transferase (NAT) 2, glutathione S-transferase (GST) M1, GSTT1, GSTP1, low Km aldehyde dehydrogenase (ALDH2), and superoxide dismutase (SOD) 2.

Results

Significant case-control distributed differences were observed in SOD2 polymorphisms and allele frequency distribution in high chemical sensitive subjects. Both the significant adjusted OR of 4.30 (95% CI, 1.23–15.03) and 4.53 (95% CI, 1.52-13.51) were observed in SOD2 Ala/Ala and Val/Ala compared to Val/Val and in SOD2 Ala/Ala compared to Val/Ala compared to Val/Val genetic analysis in the high chemical sensitivity case-control study.

Conclusions

We observed that high chemical sensitive individuals diagnosed by using Japanese criteria as MCS patients were more significantly associated with SOD2 polymorphisms.

Factors in genetic susceptibility in a chemical sensitive population using QEESI

OBJECTIVES

Inherited impairment of xenobiotic metabolism is a postulated mechanism underlying environmentally associated pathogeneses such as multiple chemical sensitivity (MCS). Using the Quick Environmental Exposure and Sensitivity Inventory (QEESI), we defined people who have a strong response to chemical substances as "chemical sensitive populations (CSP)." The aim of this study is to evaluate the condition of subjects sensitive to chemicals and to analyze their genotypes in order to identify susceptibility factors in CSPs in Japanese populations.

METHODS

A total of 1,084 employees of Japanese companies were surveyed using the QEESI, history of MCS, and sick house syndrome. The common genotypes of the participants were analyzed for glutathione S-transferase (GST) M1, GSTT1, aldehyde dehydrogenase2 (ALDH2), and paraoxonase1 (PON1) in order to identify factors in the susceptibility to sensitivity to chemicals.

RESULTS

Four subjects had history of diagnosis of MCS; no subjects had diagnosis of sick house syndrome. The subjects were divided into four levels according to scores of 0, 1-19, 20-39, and 40 or more on three of the QEESI subscales. In addition, we used the MCS criteria by Hojo to differentiate between cases (CSP) and controls. No significant differences in the allelic distribution of genetic polymorphisms in the GSTM1, GSTT1, ALDH2 or PON1 genes were found among the four levels of each subscale, or between cases and controls.

CONCLUSIONS

Our findings suggest that the common genotypes of GSTM1, GSTT1, ALDH2, and PON1 are of little importance to CSP in a Japanese population.

Sequence variations in subjects with self-reported multiple chemical sensitivity (sMCS): a case-control study

Polymorphisms in several genes contribute to interindividual differences in the metabolism of xenobiotics, and may lead to toxicity and disease. The balance between activation and/or detoxification processes may influence an individual's susceptibility to disease. One postulated mechanism underlying multiple chemical sensitivity (MCS) is based on increased metabolism of xenobiotics. The aim of the present study was to determine such polymorphisms in cases with self-reported MCS (sMCS) and controls. sMCS cases (14 men, 45 women, mean age: 48 yr) and controls (14 men, 26 women, mean age: 44 yr) of the same anthroposphere were characterized using the MCS-questionnaire from Huppe and coworkers (2000) and a standardized questionnaire for living conditions and living factors. Allelic frequencies of genomic variations for 5HTT, NAT1, NAT2, PON1, PON2, and SOD2 were determined. The MCS questionnaire from Huppe et al. (2000) differentiated between cases and controls with 87.5% sensitivity and 90% specificity. Compared to controls the sMCS cases had lower exposures, especially to odorous factors, and worse social conditions. No significant differences of the allelic distribution of genetic polymorphisms in the genes for 5HTT, NAT1, NAT2, PON1, PON2, and SOD2 were found between cases and controls. The results are in contrast to the study of McKeown-Eyssen and coworkers (2004) but in accordance with the German MCS multicenter study. Although the MCS questionnaire from Huppe et al. (2000) allowed us to differentiate sMCS cases and controls, it was not strong enough for a discrimination based on sequence variations in genes for enzymes involved in xenobiotic metabolism. Therefore, further research needs to focus on a unique phenomenological characterization of MCS.

Case-control study of genotypes in multiple chemical sensitivity: CYP2D6, NAT1, NAT2, PON1, PON2 and MTHFR

BACKGROUND

Impaired metabolism of toxic chemicals is a postulated mechanism underlying multiple chemical sensitivity (MCS). Because genetic variation alters the rate of chemical metabolism, this study was designed to determine if MCS cases differed from controls for genetic polymorphisms in drug-metabolizing enzymes.

METHODS

Female Caucasian participants (203 cases and 162 controls) were drawn from a larger case-control study based on a reproducible and validated case definition. Common polymorphisms for CYP2D6, NAT1, NAT2, PON1, and PON2 were genotyped.

RESULTS

Comparing cases and controls, significant differences were found in genotype distributions for CYP2D6 (P = 0.02) and NAT2 (P = 0.03). Compared with the referent homozygous inactive (CYP2D6) or slow (NAT2) metabolizers, the odds for being CYP2D6 homozygous active (OR = 3.36, P = 0.01) and NAT2 rapid (OR = 4.14, P = 0.01) were significantly higher in cases than controls. The odds for being heterozygous for PON1-55 (OR = 2.05, P = 0.04) and PON1-192 (OR = 1.57, P = 0.04) were also significantly higher in cases.

CONCLUSIONS

A genetic predisposition for MCS may involve altered biotransformation of environmental chemicals. The CYP2D6 enzyme activates and inactivates toxins; the NAT2 enzyme bioactivates arylamines to protein-binding metabolites. A gene-gene interaction between CYP2D6 and NAT2 suggested that rapid metabolism for both enzymes may confer substantially elevated risk (OR = 18.7, P = 0.002). Our finding parallels others' observation of a link between PON1 heterozygosity and neurological symptoms in Gulf War syndrome. This first demonstration of genetic variation in drug-metabolizing enzymes in association with MCS requires replication. However, it suggests new research directions on genetically variable toxin pathways that might be important in MCS.

Responses to panic induction procedures in subjects with multiple chemical sensitivity/idiopathic environmental intolerance: understanding the relationship with panic disorder

Idiopathic environmental intolerance (IEI), also known as multiple chemical sensitivity, is a clinical description for a cluster of symptoms of unknown etiology that have been attributed by patients to multiple environmental exposures when other medical explanations have been excluded. Because allergy has not been clearly demonstrated and current toxicological paradigms for exposure-symptom relationships do not readily accommodate IEI, psychogenic theories have been the focus of a number of investigations. A significantly higher lifetime prevalence of major depression, mood disorders, anxiety disorders, and somatization disorder has been reported among patients with environmental illness compared with that in controls. Symptoms often include anxiety, lightheadedness, impaired mentation, poor coordination, breathlessness (without wheezing), tremor, and abdominal discomfort. Responses to intravenous sodium lactate challenge or single-breath inhalation of 35% carbon dioxide versus a similar breath inhalation of clean air have shown a greater frequency of panic responses in subjects with IEI than in control subjects, although such responses did not occur in all subjects. Preliminary genetic findings suggest an increased frequency of a common genotype with panic disorder patients. The panic responses in a significant proportion of IEI patients opens a therapeutic window of opportunity. Patients in whom panic responses may at least be a contributing factor to their symptoms might be responsive to intervention with psychotherapy to enable their desensitization or deconditioning of responses to odors and other triggers, and/or may be helped by anxiolytic medications, relaxation training, and counseling for stress management.

Idiopathic environmental intolerance: increased prevalence of panic disorder-associated cholecystokinin B receptor allele 7

BACKGROUND

A growing body of evidence suggests that idiopathic environmental intolerance (IEI) is a psychophysiologic disorder with prominent features of anxiety/panic and somatization, although proponents of a toxicogenic explanation claim, despite a lack of convincing evidence, that symptoms arise from exposure to otherwise nonnoxious environmental agents. Patient behaviour is characterized by strenuous avoidance of perceived triggers to the point of severe impairment of normal social and vocational functioning. IEI proponents claim that previous studies showing a high prevalence of psychopathology in patients with IEI and studies showing panic responses to known panicogenic challenges merely reflect the anxiety-producing result of living with IEI.

OBJECTIVE

We explored whether IEI and panic disorder, personality traits, or both shared an underlying neurogenetic basis that would predate the anxiety of IEI symptomatology. The DNA of patients with IEI was examined for the presence of known panic disorder-associated cholecystokinin B (CCK-B) receptor alleles and for personality trait-associated dopamine D4 receptor polymorphisms.

METHODS

Eleven patients with typical IEI symptoms were recruited and were individually matched to normal control subjects from an existing bank for age, sex, and ethnic background. Genomic DNA was extracted from peripheral blood samples. CCK-B and dopamine D4 receptor polymorphisms were examined by using standard PCR-based techniques.

RESULTS

There was a significantly higher prevalence of the panic disorder-associated CCK-B receptor allele 7 in subjects with IEI (9/22 [40.9%]) compared with control subjects (2/22 [9.1%], P =.037). There was no difference in personality trait-associated polymorphisms of the gene encoding dopamine D4 receptor between patients and control subjects.

CONCLUSIONS

These findings provide preliminary evidence that IEI and panic disorder share a common neurogenetic basis, which would predate the anxiety-producing effects of IEI symptoms. Further studies with larger samples are warranted, but these results support previous studies that suggest that panic disorder may account for much of the symptomatology in at least some cases of IEI and provide a basis for rational treatment strategies.

A genetic rat model of cholinergic hypersensitivity: implications for chemical intolerance, chronic fatigue, and asthma

The fact that only some individuals exposed to environmental chemicals develop chemical intolerance raises the possibility that genetic factors could be contributing factors. The present communication summarizes evidence from a genetic animal model of cholinergic supersensitivity that suggests that an abnormal cholinergic system could be one predisposing genetic factor. The Flinders Sensitive Line (FSL) rats were established by selective breeding for increased responses to an organophosphate. It was subsequently found that these FSL rats were also more sensitive to direct-acting muscarinic agonists and had elevated muscarinic receptors compared to the selectively bred parallel group, the Flinders Resistant Line (FRL) rats, or randomly bred control rats. Increased sensitivity to cholinergic agents has also been observed in several human populations, including individuals suffering from chemical intolerance. Indeed, the FSL rats exhibit certain behavioral characteristics such as abnormal sleep, activity, and appetite that are similar to those reported in these human populations. In addition, the FSL rats have been reported to exhibit increased sensitivity to a variety of other chemical agents. Peripheral tissues, such as intestinal and airway smooth muscle, appear to be more sensitive to both cholinergic agonists and an antigen, ovalbumin. Hypothermia, a centrally mediated response, is more pronounced in the FSL rats after nicotine and alcohol, as well as agents that are selective for the dopaminergic and serotonergic systems. In some cases, the increased sensitivity has been detected in the absence of any changes in the receptors with which the drugs interact (dopamine receptors), while receptor changes have been seen in other cases (nicotine receptors). Therefore, there may be multiple mechanisms underlying the multiple chemical sensitivity-chemical intolerance of the FSL rats. An elucidation of these mechanisms may provide useful clues to those involved in chemical intolerance in humans.

Multiple chemical sensitivity as a conditional response

Pavlovian conditioning may contribute to some cases of multiple chemical sensitivity (MCS). On the basis of the conditioning analysis, environmental stimuli (especially olfactory cues) present at the time of a toxicant overdose become associated with the toxicant and elicit aversive conditional responses. Similar associations have been reported in patients receiving chemotherapy, and the literature on such 'pretreatment nausea' in cancer patients is relevant to understanding the role of conditioning in MCS. Evaluation of the contribution of conditioning to MCS has been complicated by confounding interpretations that emphasize conditional responses with interpretations which emphasize the psychiatric status of the patient. Appreciation of the contribution of Pavlovian conditioning to MCS will lead to a better understanding of this complex disorder.

Psychiatric illness in the first-degree relatives of persons reporting multiple chemical sensitivities

The multiple chemical sensitivities (MCS) syndrome is characterized by unexplained physical and psychiatric complaints attributed by patients and some of their physicians to low-level chemical exposures. In this study, we interviewed 15 subjects with MCS and 21 controls about their first-degree relatives using the Family History-Research Diagnostic Criteria (FH-RDC). Subjects with MCS were more likely than controls to report their relatives to have major depression, alcoholism, panic disorder, obsessive-compulsive disorder, and antisocial personality disorder. They were also likely to have past suicide attempts, and to have received some form of psychiatric treatment (hospitalization, medication or electroconvulsive therapy, or counseling). Nearly 30% of the relatives of subjects with MCS were reported to have MCS themselves. Possible reasons for the findings are discussed.

[Ecopathology of the kidneys and individual sensitivity to heavy metal salts]

Investigations performed in the region contaminated with heavy metal salts revealed high prevalence of renal diseases in children. The test for blood polymorphic proteins indicated signs of genetic predisposition to renal damage. Greater occurrence in the population with econephropathy of a rare allele of transferrin C3 may be the cause of enhanced oxidative-radical processes in renal cells. Individual sensitivity of children to heavy metal salts assessed by leukocytolysis and high incidence of somatic mutations to determine T-lymphocyte microclones deficient by HGPRT may help in specification of the affections detected in the regions contaminated with heavy metal salts.

A behavior-genetic approach to multiple chemical sensitivity

This report emphasizes the application of behavior-genetic designs to the study of sensitivity to toxic chemicals, and features of multiple chemical sensitivity and substance abuse that are polar opposites. The implications of these issues for future research are discussed in relation to twin, adoption, and sibling pair studies, as well as in relation to the degree to which genetically selected lines of rodents that have been developed in the alcoholism field are applicable to multiple chemical sensitivity.

Phenotypic variation in xenobiotic metabolism and adverse environmental response: focus on sulfur-dependent detoxification pathways

Proper bodily response to environmental toxicants presumably requires proper function of the xenobiotic (foreign chemical) detoxification pathways. Links between phenotypic variations in xenobiotic metabolism and adverse environmental response have long been sought. Metabolism of the drug S-carboxymethyl-L-cysteine (SCMC) is polymorphous in the population, having a bimodal distribution of metabolites, 2.5% of the general population are thought to be nonmetabolizers. The researchers developing this data feel this implies a polymorphism in sulfoxidation of the amino acid cysteine to sulfate. While this interpretation is somewhat controversial, these metabolic differences reflected may have significant effects. Additionally, a significant number of individuals with environmental intolerance or chronic disease have impaired sulfation of phenolic xenobiotics. This impairment is demonstrated with the probe drug acetaminophen and is presumably due to starvation of the sulfotransferases for sulfate substrate. Reduced metabolism of SCMC has been found with increased frequency in individuals with several degenerative neurological and immunological conditions and drug intolerances, including Alzheimer's disease, Parkinson's disease, motor neuron disease, rheumatoid arthritis, and delayed food sensitivity. Impaired sulfation has been found in many of these conditions, and preliminary data suggests that it may be important in multiple chemical sensitivities and diet responsive autism. In addition, impaired sulfation may be relevant to intolerance of phenol, tyramine, and phenylic food constituents, and it may be a factor in the success of the Feingold diet. These studies indicate the need for the development of genetic and functional tests of xenobiotic metabolism as tools for further research in epidemiology and risk assessment.