Cytokine mRNA expression in lung tissue from toxic oil syndrome patients: a TH2 immunological mechanism

Proteomics of toxic oil syndrome in humans: Phenotype distribution in a population of patients

OBJECTIVES

Toxic oil syndrome (TOS) is a disease that appeared in Spain in 1981. Epidemiological work traced the origin to the ingestion of aniline-adulterated rapeseed oil, fraudulently marketed and sold as edible oil. It affected more than 20,000 people with over 400 deaths in the first 2 years. In 2001 evidence was presented that genetic factors could play a role in the susceptibility of individuals to the disease. Thus, a prospective study on the differences in gene expression in sera between control versus TOS-affected populations, both originally exposed to the toxic oil, was undertaken in our laboratory.

METHODS

Differential protein expression was analyzed by two-dimensional electrophoresis (2-DE). Problems related with serum analysis by 2-DE were addressed to improve protein detection in the gel images. Three new commercial systems for albumin depletion were tested to optimize the detection of minor proteins. The use of nonionic reductants or the presence of thiourea in the gels, were also tested.

RESULTS

From the resulting optimized images, a group of 329 major gel spots was located, matched and compared with serum samples. Thirty-five of these protein spots were found to be under- or over-expressed in TOS patients (threefold increase or decrease). Proteins in these spots were identified by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) peptide map fingerprinting and database search. Several haptoglobin (Hp) isoforms were found to be differentially expressed, showing expression phenotypes that could be related with TOS. Resolution of the homologous α-1s and α-1f chains, with a mass difference of only 0.043Da, was obtained after guanidation of the protein with O-methylisourea. We applied this procedure to the study of the distribution of the Hp alleles HP(2), HP(1s) and HP(1f) in control versus TOS-affected populations. The MALDI-TOF proteotyping method was validated by a parallel analysis of the serum samples by 2-DE.

CONCLUSIONS

Data obtained from 54 TOS cases and 48 controls indicate significant differences in the distribution of Hp phenotypes in the two populations. Haptoglobin phenotypes have been reported to have biological and clinical consequences and have been described as risk factors for several diseases. Consequently, it was concluded that haptoglobin polymorphism could play a role in TOS.

Immunogenetic risk and protective factors for the development of L-tryptophan-associated eosinophilia-myalgia syndrome and associated symptoms

OBJECTIVE

To assess L-tryptophan (LT) dose, age, sex, and immunogenetic markers as possible risk or protective factors for the development of LT-associated eosinophilia-myalgia syndrome (EMS) and related clinical findings.

METHODS

HLA-DRB1 and DQA1 allele typing and Gm/Km phenotyping were performed on a cohort of 94 white subjects with documented LT ingestion and standardized evaluations. Multivariate analyses compared LT dose, age, sex, and alleles among groups of subjects who ingested LT and subsequently developed surveillance criteria for EMS, developed EMS or characteristic features of EMS (EMS spectrum disorder), or developed no features of EMS (unaffected).

RESULTS

Considering all sources of LT, higher LT dose (odds ratio [OR] 1.4, 95% confidence interval [95% CI] 1.1-1.8), age >45 years (OR 3.0, 95% CI 1.0-8.8), and HLA-DRB1*03 (OR 3.9, 95% CI 1.2-15.2), DRB1*04 (OR 3.9, 95% CI 1.1-16.4), and DQA1*0601 (OR 13.7, 95% CI 1.3-1.8) were risk factors for the development of EMS, whereas DRB1*07 (OR 0.12, 95% CI 0.02-0.48) and DQA1*0501 (OR 0.23, 95% CI 0.05-0.85) were protective. Similar risk and protective factors were seen for developing EMS following ingestion of implicated LT, except that DRB1*03 was not a risk factor and DQA1*0201 was an additional protective factor. EMS spectrum disorder also showed similar findings, but with DRB1*04 being a risk factor and DRB1*07 and DQA1*0201 being protective. There were no differences in sex distribution, Gm/Km allotypes, or Gm/Km phenotypes among any groups.

CONCLUSION

In addition to the xenobiotic dose and subject age, polymorphisms in immune response genes may underlie the development of certain xenobiotic-induced immune-mediated disorders, and these findings may have implications for future related epidemics.

In Vitro Bioactivation of 3-(N-Phenylamino)propane-1,2-diol by Human and Rat Liver Microsomes and Recombinant P450 Enzymes. Implications for Toxic Oil Syndrome

Toxic oil syndrome (TOS) was a massive food-borne intoxication that occurred in Spain in 1981. Epidemiological studies imputed 3-( N-phenylamino)propane-1,2-diol (PAP) derivatives as the toxic agents. The in vitro bioactivation of PAP by rat and human liver microsomes was studied. In both cases, 3-[ N-(4'-hydroxyphenyl)amino]propane-1,2-diol ( 1) was detected as the main metabolite. Inhibition studies with pooled human liver microsomes in the presence and absence of P450-specific inhibitors suggest that 2C8 and 2E1 are the main enzymes involved in PAP bioactivation, followed by 3A4/5, 1A1/2, and 2C9. Incubations of PAP with 10 different recombinant P450 enzymes showed that 2C8, 2C9, 2C18, 2D6, and 2E1 catalyzed PAP 4'-hydroxylation. Incubations of phenol 1 with rat and human liver microsomes in the presence of GSH resulted in the formation of a glutathione conjugate of a quinoneimine metabolite derived from 1. In rat liver microsomes, P450 enzymes play a key role in the bioactivation of 1, whereas in human liver microsomes, autoxidation appears to be the major mechanism. The implications of these results for toxic oil syndrome are discussed.

Genetic approaches in the understanding of Toxic Oil Syndrome

The Toxic Oil Syndrome (TOS) is a multisystemic disease that occurred in Spain in 1981 due to the ingestion of rapeseed oil denatured with 2% aniline. Female prevalence and the different clinical evolution even inside the same family (similar exposition), pointed to genetic implications. Furthermore, HLA-DR2 was increased in patients dead because of TOS. Th2 activation and eosinophilia implicated immunological mechanisms. For those reasons we firstly decided, to do a genome-wide search by linkage mapping set along the chromosome 6 (where HLA loci are located), to identify loci associated to the TOS development. The design was case-control-matched (n = 328). By this procedure, microsatellite (near to HLA) was related with the patients. After fine-mapping around this marker, we defined four more closely related to TOS-, , and . Secondly, we analysed in 420 patients, the association of these four markers with 14 TOS clinical phenotypes. We demonstrated that alveolar infiltration, liver disease and scleroderma are clearly associated with . As conclusion, we have identified in chromosome 6, a region where are located some genes related with autoimmune diseases, associated with certain TOS phenotypes, pointing out the possible role of autoimmune reactions in the pathogenesis of the disease.

Toxic oil syndrome: Genetic restriction and immunomodulatory effects due to adulterated oils in a model of HLA transgenic mice

Toxic oil syndrome (TOS) was described in Spain in 1981, due to the ingestion of contaminated rapeseed oil denatured with 2% aniline. More than 20,000 persons were affected, causing over 2500 deaths. Immunological findings were: eosinophilia, mRNA for Th2 cytokines (IL-4 and IL-5) in lungs, elevated total IgE and sIL-2R and increase of DR2 HLA class II phenotypic frequency in patients died by TOS. Our objective is to test the genetic restriction found in humans using HLA transgenic mice. Results show that mice expressing human DR2 and DQ6 (both in linkage disequilibrium), had higher percentage of eosinophils (DQ6) and IgE (DR2) than other transgenic mice tested (DR3 and DR4). Also, a Th2 shift was found in DR2 transgenic mice when toxic oil was administered with OVA. This has been corroborated by the IL-5 mRNA expression in 4 out of 6 lung tissues from TOS oil treated BALB/c mice. These data indicate that an immunological response was induced as consequence of the toxic administration. These results correlate with those found in TOS patients and reinforce the implication of genetic restrictions in the acquisition of toxic-mediated disease.

Investigating the onset of autoimmunity in A.SW mice following treatment with 'toxic oils'

In 1981, over 20,000 people were struck with toxic oil syndrome (TOS). H-2s strains of mice have been shown to develop symptoms of TOS after exposure to toxic oil. We examined the effects of toxic oil on A.SW mice, which are susceptible to chemically-induced autoimmunity, but do not spontaneously develop autoimmune disease. Mice were treated with three types of toxic oil: CO756 (case oil from Spain), RSD99 (rapeseed oil with no 3-(N-phenylamino)-1-2-propanediol (PAP) derivatives) and RSA99 (rapeseed oil supplemented with PAP derivatives). Mercuric chloride treated mice were used as a positive control. After toxic oil treatment, there were no consistent differences in body weight or organ weight (liver, kidney, thymus and spleen) as a percent of body weight at any of these timepoints: 2.5, 5 or 10 weeks. We also found that treatment with toxic oil did not induce autoantibody formation or lead to increased serum levels of IgG1, IgG2a or IgE at these timepoints. Conversely, at all timepoints, there were significant increases in organ weight as a percent of body weight in the mercury treated mice. Additionally, mercuric chloride treated mice had elevated serum levels of IgG1, IgG2a and IgE and developed anti-nuclear and anti-collagen antibodies.

A search for an animal model of the Spanish toxic oil syndrome

To date, pathology characteristics of toxic oil syndrome (TOS), a disease associated with consumption of a contaminated cooking oil in Spain in 1981, have not been reproduced in an animal model. As vasculitis, eosinophilia, and a rise in circulating IgE levels were features of the acute phase of TOS, leading to an autoimmune outcome, a review of predisposition to these aspects across species was conducted. The intent was to determine predisposed strains or species that potentially might be effective in testing the toxic oils and thus defining the precise identity of the toxic contaminant(s). A number of potential candidates emerge from this review. Among mice, these include the NZB mouse hybrids, the MRL/lpr and SJL/J strains, and a transgenic mouse model of eosinophilia. The Brown Norway may be the most appropriate rat strain, while beagle dogs inbred to be genetically predisposed to immune complex disease and vasculitis are also a candidate species. Of the more exotic species, the mink and ferret have characteristics that might make them suitable candidates for testing oil samples.

Immunoglobulin and autoantibody responses in MRL/lpr mice treated with 'toxic oils'

The toxic oil syndrome (TOS) occurred in Spain in 1981 as a result of ingestion of oil mixtures containing aniline-denatured rapeseed oil. The disease afflicted almost 20000 people, resulted in more than 400 deaths, and mimicked an autoimmune disease in all patients. Phenilamine-propanediol (PAP) has been implicated as a possible etiologic agent of TOS but absence of an acceptable animal model to evaluate the autoimmune potential of the 'case oil' has hindered identification of the actual etiologic agent(s). The purpose of this study was twofold; (1) to develop an animal model of human disease to investigate the immunological etiology and pathogenesis of TOS and (2) to determine if the 'case oil' responsible for TOS and/or two synthesized oils either induced or exacerbated the systemic autoimmune disease that occurs spontaneously in the MRL/lpr mouse. The oils tested were a denatured rapeseed oil collected from a family (case oil) who were affected by the TOS (CO756), a rapeseed oil denatured with 2% aniline and enriched with a mixture of diesters of PAP (RSD), and a rapeseed oil denatured with 2% aniline but contained no diesters of PAP (RSA). Female MRL/lpr mice, 7 weeks of age, received orally either an undiluted (neat) or a 1:10 diluted dose of each test oil, canola oil (oil control), water (nai;ve control), or 50-ppm mercury (positive control). Half of each group was sacrificed after 5 weeks of exposure and the remaining mice after 10 weeks of exposure. Serum IgG1, IgG2a, IgE isotypes and antinuclear (ANA), collagen type II, histone, single-stranded DNA (ssDNA), double-stranded DNA (dsDNA) and Sm autoantibody concentrations were determined after 5 and 10 weeks of exposure. The oils did not significantly affect the concentrations of the serum immunoglobulins, although a shift in the IgG1:IgG2a ratio towards IgG1 was noted from 12 to 17 weeks of age (5-10 weeks of treatment). The oils did however stimulate the systemic autoimmune response. The RSD neat treatment resulted in a nonsignificant but noted increase in autoantibodies to collagen (10 weeks), histone (10 weeks) and dsDNA (5 and 10 weeks). CO756 neat increased the serum levels of ANA (5 weeks), collagen (5 weeks) and dsDNA (5 and 10 weeks). The RSA 1:10 dilution increased ssDNA and dsDNA autoantibodies at 5 weeks. The results suggest that PAP is an active principle of these noted responses. These data, coupled with the toxicology and pathology data from this study (Toxicol. Path. 29 (2001) 630), revealed that the three oils incited induction of the lymphoproliferative syndrome and that the two oils containing PAP induced and enhanced the systemic autoimmune response that develops spontaneously at an early age in the MRL/lpr mouse. There was also a positive correlation noted between serum autoantibody concentrations and progression of the idiopathic autoimmune syndrome in the MRL/lpr mouse.

Metabolism of R,S enantiomers of 3-phenylamino-1,2-propanediol, a compound associated with the toxic oil syndrome, in C57BL/6- and A/J-strain mice

PAP, a very polar substance, is highly metabolized in mice and excreted principally in urine in the form of the 2-hydroxy-3-phenylaminopropanoic acid of each enantiomer. Thus, the major route of PAP elimination in these strains is alkyl chain oxidation. In particular, S-PAP is eliminated principally in the form of that metabolite, whereas R-PAP enantiomer showed further oxidized species at the aromatic ring and alkyl chain, yielding potential decarboxylated compounds and iminoquinones. All these metabolites may have toxicologic implications. On the other hand, OOPAP intestinal hydrolysis in favour of one PAP enantiomer might be expected since lipases show chiral hydrolysis (unpublished data, manuscript in preparation). In this respect, enantiomeric distribution and metabolic differences should be taken into account in the toxicokinetics of these compounds and their potential association with Toxic Oil Syndrome symptoms.

[The carpal tunnel syndrome in the oil toxic syndrome]

BACKGROUND

The toxic oil syndrome (TOS) is an autoimmune disease caused by the ingestion of aniline-denatured rapeseed oil. The carpal tunnel syndrome (CTS) is an entrapment neuropathy due to the median nerve entrapment, which is associated with both occupational activities and autoimmune diseases. The objective of this work was to know the frequency and characteristics of CTS in TOS patients.

PATIENTS AND METHODS

Between December 1977 and July 2000, 744 TOS patients were evaluated. The inclusion criteria were: the clinical records for patients diagnosed between May 1981 and November 1997; and for patients diagnosed between December 1997 and July 2000, symptoms with the classical or likely pattern according to the Katz's hand diagram and one of the following findings: a) abnormal electromyogram, and b) hypalgesia in the median nerve territory and positive Tinel and/or Phalen signs.

RESULTS

A total of 70 patients (63 women, 90%) were diagnosed; 48 of them had been diagnosed before 1997 and 22 subsequently. The mean age of patients was 47.6 (20-78) years. In 36 patients (51.4%), a bilateral CTS was present. Fifty-six patients (81.4%) had a diagnostic EMG, and 31 (44.2%) were obese, 13 (18.6%) diabetic, and 4 (6%) had hypothyroidism. Most of these cases (48; 68.6%) were housewives.

CONCLUSIONS

TOS patients have a high frequency of CTS; therefore, this condition must be suspected in patients with associated obesity and diabetes mellitus.

Metabolism of (R)- and (S)-3-(phenylamino)propane-1,2-diol in C57BL/6- and A/J-strain mice. Identification of new metabolites with potential toxicological significance to the toxic oil syndrome

The Toxic Oil Syndrome was a massive food-borne intoxication that occurred in Spain in 1981. Epidemiological studies point to 3-(phenylamino)propane-1,2-diol (PAP) derivatives as the putative toxic agents. We report further identification of metabolites cleared in urine of A/J and C57BL/6 mice in which (R)- and (S)-3-(phenylamino)propane-1,2-diol were administered intraperitoneally. This investigation is an extension of previous studies carried out with the racemic compound [Ladona, M. G., Bujons, J., Messeguer, A., Ampurdanés, C., Morató, A., and Corbella, J. (1999) Chem. Res. Toxicol. 12, 1127-1137]. Both PAP enantiomers were extensively metabolized, and several metabolites were eliminated in urine. The HPLC profiles of the urine samples of both mouse strains treated with each enantiomer were qualitatively similar, but differences were found in a relatively higher proportion of several detected metabolites in mice treated with (R)-PAP compared with those treated with (S)-PAP. The main urine metabolite continues to be 2-hydroxy-3-(phenylamino)propanoic acid (1), which confirms our previous results obtained with rac-PAP. In addition to the detection of other metabolites already reported in our previous paper, interesting evidence is provided on the presence of 4-aminophenol and paracetamol conjugates in the urine samples from both mouse strains. The detection of these metabolites suggests the in vivo formation of quinoneimine PAP derivatives. Indeed, some quinoneimine species (11 and 12), as well as other PAP metabolites (13) that bear modifications in the alkyl chain, have been tentatively identified in mouse urine. These metabolic findings might imply a potential toxicological significance for the Toxic Oil Syndrome.

Short-term adverse effects in humans of ingested mineral oils, their additives and possible contaminants--a review

The toxicological databases for petroleum refinery products such as mineral oils, as well as for their potential contaminants and additives, were reviewed for human cases of poisoning by the oral route. The aim was to determine whether any overlooked adulterant in the oil implicated as the cause of the 1981 outbreak of Toxic Oil Syndrome (TOS) in Spain, may have been responsible for the unusual symptomatology characterizing this disease. The essential features of TOS were peripheral eosinophilia, pulmonary oedema and endothelial damage in the acute phase; myalgia, sensory neuropathy, hepatic injury, skin oedema and sicca in the intermediate phase; and peripheral neuropathy, muscle wasting, scleroderma and hepatopathy in the chronic phase. Of the more than 70 chemical entities and mixtures reviewed here, none had been reported as producing adverse toxic effects upon ingestion resembling the specific set of symptoms and progression that characterized TOS. Because of their viscosity, the most commonly recorded disease process associated with oral ingestion of petroleum refinery products was lipid pneumonia, implicating lung exposure via aspiration. The mineral oil additives and contaminants comprised a highly diverse range of chemical entities, producing a variety of symptoms in instances of poisoning. Specifically, no chemical entity amongst the refinery products, additives or contaminants was described as inducing a syndrome involving vasculitis accompanied by thrombotic events, along with immunological consequences (such as T-lymphocyte activation and cytokine release), as is considered to be the cellular basis of TOS.

Biotransformation and clearance of 3-(phenylamino)propane-1,2-diol, a compound present in samples related to toxic oil syndrome, in C57BL/6 and A/J mice

In May 1981, a massive food-borne intoxication occurred in Spain. The so-called toxic oil syndrome (TOS) was associated with the consumption of aniline-denatured and refined rapeseed oil that was illegally sold as edible olive oil. Fatty acid anilides and fatty acid derivatives of 3-(phenylamino)propane-1,2-diol were detected in oils and implicated as potential toxic agents and markers of toxic oil batches. Epidemiological evidence points to 3-(phenylamino)propane-1,2-diol derivatives as the putative toxic agents, which were generated during the refining process at the ITH refinery. Here we present the biotransformation and clearance of 3-(phenylamino)propane-1,2-diol (PAP) administered intraperitoneally to A/J and C57BL/6 mice that have been proposed as a murine model for the immunological features of TOS. Mice eliminated 6 microCi of [U-(14)C]PAP during a 24 h period, mostly in urine. Animals exhibited urine elimination rates of 70 and 36% in A/J and C57BL/6 strains, respectively. A/J mice exhibited no increase in the elimination rate when induced with beta-naphthoflavone, whereas C57BL/6 did increase the rate of elimination to 57%. Feces contributed to a lesser extent to the elimination rate (0.6 and 3.3% in A/J and C57BL/6 mice, respectively). Radioactivity remaining in organ tissues was lower than 1% (liver, lung, kidney, spleen, heart, and muscle). Metabolic species in urine were identified by HPLC coupled to UV and radioisotope detectors and further GC/MS analyses. 2-Hydroxy-3-(phenylamino)propanoic acid metabolite was the major chemical species excreted in urine in both strains, in both control and induced animal groups. This compound was the main urinary metabolite of PAP, and unmetabolized PAP excreted in urine constituted less than 1% of the total administered dose. Two additional highly polar metabolites also detected in urine were identified as 3-[(4'-hydroxyphenyl)amino]propane-1,2-diol and 2-hydroxy-3-[(4'-hydroxyphenyl)amino]propanoic acid. These findings are the first reported on PAP metabolism and clearance in mice strains and suggest that PAP can be extensively metabolized in vivo and potential reactive species can be generated.

Study of apoptosis in human lymphocytes by toxic substances implicated in toxic oil syndrome

Toxic Oil Syndrome is a multisystemic disease that occurred in epidemic proportions in Spain in 1981 caused by the ingestion of rapeseed oil denatured with aniline. Several data implicate T cells in the pathogenesis of the disease. We evaluated the mechanisms of cytotoxicity in human lymphocytes of TOS-related products: aniline, 3-(N-phenylamino)-1,2-propanediol and its mono- and di-oleyl esters and eosinophilia myalgia-related product such as 3-(phenylamino)-L-alanine, which is chemically similar to 3-(N-phenylamino)-1,2-propanediol, and has been found in manufactured L-tryptophan. Our results show that only di-oleyl ester of 3-(N-phenylamino)-1,2-propanediol induces apoptosis in human lymphocytes, in a concentration and time-dependent way, confirmed by morphology, expression of phosphatidylserine in membrane and analysis of DNA degradation.