Immunologic and renal markers among photogravure printers exposed to toluene

Isolated Pauci-Immune Pulmonary Capillaritis Associated with Hydrocarbon Inhalation and Marijuana Smoking: An Unusual Case of Severe Hypoxemia

We present a case report of a patient with Isolated pauci-immune pulmonary capillaritis (IPIPC). A 40-year-old male presented with acute onset severe hypoxemic respiratory failure. He had just returned home from work as a cabinetmaker, where he experienced inhalational exposure to hydrocarbons and solvents, and had smoked a marijuana cigarette. He was hypotensive, and his chest imaging showed bilateral dependent infiltrates. His hypoxemia made little improvement after conventional ventilator support and broad-spectrum antibacterial therapy and he was considered too unstable to tolerate diagnostic bronchoscopy with bronchoalveolar lavage. His laboratory evaluation initially showed microscopic hematuria which later cleared, but other tests including serologic autoimmune assessment were negative, and he did not have any traditional risk factors for vasculitis. A video-assisted thoracoscopic lung biopsy revealed diffuse alveolar hemorrhage with pulmonary capillaritis on histopathology. He was diagnosed with IPIPC and initiated on immunosuppressive therapy. He was soon liberated from mechanical ventilation and improved to hospital discharge. Diffuse alveolar hemorrhage from Goodpasture's Syndrome has manifested following inhalation of hydrocarbons and following smoking. This has not previously been reported with IPIPC. Given the lack of other findings and risk factors, his IPIPC was likely associated with occupational exposures to hydrocarbons as a cabinetmaker compounded by marijuana smoking.

Different sensitivity in expression of transcription factor mRNAs in congenic mice following exposure to low-level toluene

To investigate the relationship between sensitivity to toluene exposure and genetic background, male congenic mice, C57BL/10 (H-2(b)) and B10.BR/Sg (H-2(k)) were exposed to 0, 5, and 50 ppm toluene for 6 h per day, 5 days per week for 6 weeks. Groups of mice were injected with ovalbumin (OVA) intraperitoneally before starting exposure schedule and these mice were then challenged with aerosolized OVA as a booster. Following 24 h of the last exposure, the spleens were collected. We examined spleen cell proliferation using DNA synthesis and T-helper 1/2-related transcription factor genes in spleen of two congenic mice using real-time reverse transcriptase-polymerase chain reaction. Although lipopolysaccharide-induced (LPS-induced) cell proliferation was significantly increased in 50 ppm toluene-exposed, nonimmunized B10.BR mice but not in C57BL/10 mice, exposure to 50 ppm toluene significantly decreased LPS-induced cell proliferation in immunized B10.BR mice. The expression of transcription factor forkhead box P3, signal transducers and activators of transcription (STAT)5 and STAT6 mRNAs was significantly increased in spleen from 5 ppm toluene-exposed, OVA-immunized B10.BR mice, but not in those of C57BL/10 mice. Although there may be other differences unrelated to H-2 locus between the congenic mice of the same background, the findings of the present study strongly suggest a possible role of H-2 locus in the toluene-induced immune disturbance.

Exposure to volatile organic compounds and kidney dysfunction in thin film transistor liquid crystal display (TFT-LCD) workers

Many volatile organic compounds (VOCs) are emitted during the manufacturing of thin film transistor liquid crystal displays (TFT-LCDs), exposure to some of which has been reported to be associated with kidney dysfunction, but whether such an effect exists in TFT-LCD industry workers is unknown. This cross-sectional study aimed to investigate the association between exposure to VOCs and kidney dysfunction among TFT-LCD workers. The results showed that ethanol (1811.0+/-1740.4 ppb), acetone (669.0+/-561.0 ppb), isopropyl alcohol (187.0+/-205.3 ppb) and propylene glycol monomethyl ether acetate (PGMEA) (102.9+/-102.0 ppb) were the four dominant VOCs present in the workplace. The 63 array workers studied had a risk of kidney dysfunction 3.21-fold and 3.84-fold that of 61 cell workers and 18 module workers, respectively. Workers cumulatively exposed to a total level of isopropyl alcohol, PGMEA and propylene glycol monomethyl ether> or =324 ppb-year had a significantly higher risk of kidney dysfunction (adjusted OR=3.41, 95% CI=1.14-10.17) compared with those exposed to <25 ppb-year after adjustment for potential confounding factors. These findings indicated that array workers might be the group at greatest risk of kidney dysfunction within the TFT-LCD industry, and cumulative exposure to specific VOCs might be associated with kidney dysfunction.

Children's immunology, what can we learn from animal studies (2): Modulation of systemic Th1/Th2 immune response in infant mice after prenatal exposure to low-level toluene and toll-like receptor (TLR) 2 ligand

It has been reported that the newborn immune system differs quantitatively and functionally from that of adults. Development of the immune system has important implications for childhood diseases. The immaturity of the immune system in the prenatal or suckling stage may contribute to susceptibility to environmental toxic chemical exposure. In the present study, to clarify the effect of low-level toluene exposure on immune functions during developmental stage, pregnant mice were exposed to 0, 5, and 50 ppm toluene from gestational day 14 to day 19 with or without stimulation by peptidoglycan (PGN) of a gram-positive bacterial cell wall component, a toll-like receptor (TLR) 2 ligand. We examined Th1/Th2 balance in the offspring's at 3 weeks old using ELISA and real-time RT-PCR methods. Exposure of mice to 50 ppm toluene enhanced total immunoglobulin (Ig) G2a (Th1-dependent) level in plasma. On the other hand, splenic expression of transcription factor T-bet (Th1-specific), GATA-3 (Th2-specific) and Foxp3 (gene marker for regulatory CD4+CD25+ T-cells) mRNAs was suppressed in these mice, but not in the combination of 5 or 50 ppm toluene with PGN. In addition, total IgG1 (Th2 dependent) level was suppressed in the combination of 5 or 50 ppm toluene with PGN. Our findings indicate that modulation of Th1- and Th2-responses may occur in low-level toluene exposure and/or combination with PGN stimulation in infant mice.

Effect of long-term exposure to low-level toluene on airway inflammatory response in mice

Volatile organic compounds are the main substances causing multiple chemical sensitivity reactions in human. Our laboratory has previously showed that the exposure of low-level formaldehyde causes immunogenic and neurogenic inflammatory responses in mice. The aim of the present study was to investigate the effect of long-term, low-level toluene exposure on airway inflammatory responses in mice lung. We exposed female C3H mice to filtered air (0ppm) or 50ppm of toluene for 6h/day on 5days/week for 6 or 12 weeks in the whole body exposure chamber. One day following the last toluene exposure, we collected bronchoalveolar lavage fluid from each mouse and examined cellular infiltration and production of cytokines, chemokines, neurotrophins and substance P by using ELISA method. We found that the number of total cells and macrophages increased significantly in both 6 and 12-week-exposed mice. In addition, the production of interferon-gamma and substance P were decreased significantly and nerve growth factor was not affected in both 6 and 12-week-exposed mice. In contrast, neurotrophin-3 production in bronchoalveolar lavage fluid was significantly increased only in 12-week-exposed mice. Our findings suggest that long-term (12-week) exposure of mice to low-level toluene modulates airway inflammatory response via neurological signaling.

Occupational exposure to toluene and its possible causative role in renal damage development in shoe workers

OBJECTIVES

An important, although, unprecise number of shoe workers in Leon, Mexico, are in continuous contact with toluene-based glues. The induction of renal glomerular and/or tubular lesions as a result of toluene exposure is still being discussed controversially. Our objective was to evaluate the extent of occupational exposure, assessing urinary o-Cresol excretion as a measure for toluene exposure in a population at risk as compared to a control population. Urinary albumin excretion (UAE) and N-acetyl-beta-D-glucosaminidase (NAG) enzymatic activity were tested to assess renal dysfunction.

METHODS

A cross-sectional study was performed comparing 50 toluene-exposed shoe workers and 25 control subjects. Urinary o-cresol was assessed on first and last day of labor week from exposed subjects. A single urine sample was obtained from control subjects. Urinary Albumin excretion (UAE) and (NAG) activity were examined in 12 h urine samples in all subjects. Urine and serum creatinine were measured to asses renal function.

RESULTS

At the end of the labor week, urinary o-cresol levels were higher in samples obtained from exposed subjects. Albumin excretion was similar in the exposed and control groups. NAG activity was greater in the exposed group compared to control group (median 3.5 U/g creatinine vs 1.9 U/g creatinine, z=2.6, P=0.009). An inverse relationship was found between schooling years and the NAG enzymatic activity for the two studied groups (r= -0.27, P=0.02),

CONCLUSIONS

Our findings support the hypothesis that toluene may be a factor associated with the presence of renal damage in exposed shoe workers. As NAG activity is increased, we believe the lesion initiates in the renal tubular cells.

Nephrotoxicity of organic solvents: biomarkers for early detection

OBJECTIVES

Evidence for a relationship between chronic kidney diseases or progression of already existing diseases (glomerulonephritides) and occupational solvent exposure has been found in case reports, in case-control studies and also in cross-sectional studies. An analysis of the available literature was performed with respect to markers measured in cross-sectional studies that might be useful for an early detection of solvent-induced effects on the kidney.

METHODS

The relevant cross-sectional studies were evaluated and the following markers were analyzed with respect to their suitability as biomarker for renal damage: total protein, albumin, transferrin, IgG, beta(2)-microglobulin, retinol-binding protein, N-acetyl-beta-D: -glucosaminidase, alanine aminopeptidase, beta-galactosidase, beta-glucuronidase, leucin aminopeptidase, alkaline phosphatase, lysozyme, Tamm-Horsfall protein and laminin fragments in urine as well as E-selectin, laminin and anti-laminin antibodies and anti-glomerular basement membrane antibodies in serum.

RESULTS

An increased albumin excretion was observed more frequently in groups of workers exposed to various solvents (like toluene, styrene, aliphatic/aromatic hydrocarbon mixtures, tetrachloroethene, mixtures of chlorinated hydrocarbons) than in controls. No clear pattern emerged for the other markers.

CONCLUSIONS

The determination of albumin excretion in the urine appears to be a useful parameter for monitoring solvent-exposed workers.

Outcomes in patients with Goodpasture's syndrome and hydrocarbon exposure

Goodpasture's Syndrome has been associated with hydrocarbon exposure. No study has examined outcomes in these patients. All reported cases of Goodpasture's Syndrome and hydrocarbon exposure were identified using MEDLINE and was analyzed for factors related to outcomes. A total of 43 cases were identified since 1969. The mean age of patients was 28 years old. There was a slight predilection for males (60%) when analyzing gender. Various types of hydrocarbons were identified and the duration of exposure varied from minutes to years. A majority of patients (86%) had pulmonary hemorrhage and antiglomerular basement membrane antibodies (AGBM) (92%). Patients were treated with immunosuppressive agents. The only significant statistical correlation was female patients with hydrocarbon exposure were younger. There was no correlation between age, gender, duration of exposure, presence of pulmonary hemorrhage or AGBM, or other risk factors and outcome. The relationship between hydrocarbon exposure and Goodpasture's Syndrome remains unclear since only 6% of cases in the literature had exposure. Even though most patients survived, no factor studied affected outcome making it difficult to predict prognosis in these patients.

Color vision and occupational toluene exposure

We examined the relationship between acquired color vision loss and exposure to toluene and total hydrocarbons among 125 male workers. Seventy-two toluene-exposed printers were compared with 34 workers from the same photogravure plant with ambient background exposure, and with 19 workers from a bookbinding plant located in the same town (nonexposed). Environmental mean toluene exposure level at workstation was estimated from individual 8-h sampling. Historic exposure data from the last 30 years were used to construct two cumulative exposure indices, one for toluene and one for total hydrocarbons. Airborne toluene levels were overall lower than the current Threshold Limit Value (TLV) of 50 ppm. Color vision was assessed by the Lanthony D-15 desaturated panel. Color vision loss was quantitatively established by the Color Confusion Index (CCI) and classified by type of acquired dyschromatopsia according to Verriest's classification. CCI was positively related to current airborne toluene levels, and cumulative exposure indices for toluene and total hydrocarbons (.18< or =r< or =.35). Odds ratios of acquired dyschromatopsia were significant for current airborne toluene, toluene, and total hydrocarbon past exposure (1.27 [1.02-1.58], 1.21 [1.04-1.39], 1.15 [1.02-1.31], respectively). In conclusion, this study suggests that the Lanthony D-15 desaturated panel detects early neurotoxic effects among workers exposed to toluene.

Influence of renal biomarker variability on the design and interpretation of occupational or environmental studies

OBJECTIVES

To quantify and identify sources of within- and between-subject variability of microalbumin, N-acetyl-beta-D-glucosaminidase (NAG) and alanine aminopeptidase (AAP), three biomarkers used for early detection of renal injury, and to assess the consequences of this variability for the design and power of epidemiological studies.

METHODS

Urinary excretion of microalbumin, NAG, AAP and creatinine as well as blood pressure (BP) were measured three times over a 2-year period among 142 healthy male workers. To minimise physiopathological and analytical sources of variation, standardised methods were used for urine collection and assays, and severe exclusion criteria were applied. At the first and third examinations, subjects completed the same questionnaire, providing information about their personal characteristics, tobacco and alcohol consumption, and health. A linear mixed model was used to estimate the within- and between-subject variance components and to analyse the relation between subjects' characteristics and the biomarkers.

RESULTS

No change in the mean value of any of the biomarkers was observed over the 2-year period. Intra-class correlation coefficients between repeated measurements were 0.53, 0.57 and 0.56 for microalbumin, NAG and AAP, respectively; the between-subject variance was slightly higher than the within-subject variance. Subjects' age, BP, body mass index and smoking and drinking habits explained 7.2%, 12.5% and 4.2% of the total variance of microalbumin, NAG and AAP, respectively.

CONCLUSIONS

In this healthy population of male workers, day-to-day differences in biomarker values appeared to be nearly as great as differences between subjects. The within-subject variance of these biomarkers is not high enough to justify systematic repeated measurements in epidemiological surveys. But, in some situations where the number of subjects is limited, measuring the subjects twice may improve study power by reducing the total variance by about 25% for each biomarker. Taking the above covariates into account would slightly improve study power and the accuracy of parameter estimates for NAG, but would add little to the analysis of microalbumin and AAP.