Renal toxicity of middle distillates of shale oil and petroleum in mice

Experimental glomerulonephritis induced by hydrocarbon exposure: a systematic review

BACKGROUND

Much epidemiological evidence suggests that hydrocarbon exposure may induce glomerulonephritis and worsen its course in many patients. The mechanisms are unknown, however, no specific microscopic pattern has been identified, and it has also been argued that hydrocarbon exposure causes tubular damage mainly. Studying experimental animals may best answer these questions, and as no systematic review of glomerulonephritis produced experimentally by hydrocarbon exposure has been performed previously, I found it relevant to search for and analyse such studies.

METHODS

Animal experiments having mimicked human glomerulonephritis by hydrocarbon exposure were sought on Medline and Toxnet

RESULTS

Twenty-six experiments using thirteen different hydrocarbons were identified. Several human subtypes were observed including IgA nephritis, mesangial, proliferative and extracapillary glomerulonephritis, focal and focal-segmental sclerosis, minimal change nephropathy, anti-GBM and anti-TBM nephritis, and glomerulonephritis associated with peiarteritis nodosa. Glomerular proteinuria was seen in 10/12 experiments that included urine analyses, and renal failure in 5/8 experiments that included measurements of glomerular function. All experiments resulted in various degrees of tubular damage as well. In most studies, where the animals were examined at different times during or after the exposure, the renal microscopic and functional changes were seen immediately, whereas deposits of complement and immunoglobulins appeared late in the course, if at all.

CONCLUSION

These experiments are in accord with epidemiological evidence that hydrocarbon exposure may cause glomerulonephritis and worsen renal function. Probable mechanisms include an induction of autologous antibodies and a disturbance of normal immunological functions. Also, tubular damage may increase postglomerular resistance, resulting in a glomerular deposition of macromolecules. In most models a causal role of glomerular immune complex formation was unlikely, but may rather have been a secondary phenomenon. As most glomerulonephritis subgroups were seen and as some of the hydrocarbons produced more than one subgroup, the microscopic findings in a patient cannot be used as a clue to the causation of his disease. By the same reason, the lack of a specific histological pattern in patients with glomerulonephritis assumed to have been caused by hydrocarbon exposure is not contradictive.

Biological and health effects of exposure to kerosene-based jet fuels and performance additives

Over 2 million military and civilian personnel per year (over 1 million in the United States) are occupationally exposed, respectively, to jet propulsion fuel-8 (JP-8), JP-8 +100 or JP-5, or to the civil aviation equivalents Jet A or Jet A-1. Approximately 60 billion gallon of these kerosene-based jet fuels are annually consumed worldwide (26 billion gallon in the United States), including over 5 billion gallon of JP-8 by the militaries of the United States and other NATO countries. JP-8, for example, represents the largest single chemical exposure in the U.S. military (2.53 billion gallon in 2000), while Jet A and A-1 are among the most common sources of nonmilitary occupational chemical exposure. Although more recent figures were not available, approximately 4.06 billion gallon of kerosene per se were consumed in the United States in 1990 (IARC, 1992). These exposures may occur repeatedly to raw fuel, vapor phase, aerosol phase, or fuel combustion exhaust by dermal absorption, pulmonary inhalation, or oral ingestion routes. Additionally, the public may be repeatedly exposed to lower levels of jet fuel vapor/aerosol or to fuel combustion products through atmospheric contamination, or to raw fuel constituents by contact with contaminated groundwater or soil. Kerosene-based hydrocarbon fuels are complex mixtures of up to 260+ aliphatic and aromatic hydrocarbon compounds (C(6) -C(17+); possibly 2000+ isomeric forms), including varying concentrations of potential toxicants such as benzene, n-hexane, toluene, xylenes, trimethylpentane, methoxyethanol, naphthalenes (including polycyclic aromatic hydrocarbons [PAHs], and certain other C(9)-C(12) fractions (i.e., n-propylbenzene, trimethylbenzene isomers). While hydrocarbon fuel exposures occur typically at concentrations below current permissible exposure limits (PELs) for the parent fuel or its constituent chemicals, it is unknown whether additive or synergistic interactions among hydrocarbon constituents, up to six performance additives, and other environmental exposure factors may result in unpredicted toxicity. While there is little epidemiological evidence for fuel-induced death, cancer, or other serious organic disease in fuel-exposed workers, large numbers of self-reported health complaints in this cohort appear to justify study of more subtle health consequences. A number of recently published studies reported acute or persisting biological or health effects from acute, subchronic, or chronic exposure of humans or animals to kerosene-based hydrocarbon fuels, to constituent chemicals of these fuels, or to fuel combustion products. This review provides an in-depth summary of human, animal, and in vitro studies of biological or health effects from exposure to JP-8, JP-8 +100, JP-5, Jet A, Jet A-1, or kerosene.

Hydrocarbons may worsen renal function in glomerulonephritis: a meta-analysis of the case-control studies

BACKGROUND

Previous case-control studies of hydrocarbon exposure in glomerulonephritis may have given inconsistent results because the stage of disease has not been considered.

METHODS

The association between stage of disease and degree of previous exposure was studied by a meta-analysis of all published case-control studies and by reviewing all follow-up studies.

RESULTS

Odds ratios (OR) for exposure could be calculated for 16 patient groups from 14 case-control studies. After exclusion of four patient groups with 5-17% drop-outs due to death, the mean weighted OR for patient groups with acute or early glomerulonephritis, chronic renal failure, and end-stage renal failure were 0.95, 3.1, and 5.9, respectively. At follow-up, reported in four studies, renal failure was mainly seen in patients with extensive exposure, and improvement was seen only in patients who had discontinued the exposure.

CONCLUSIONS

Hydrocarbon exposure in glomerulonephritis is associated with the advancement of the disease and inversely associated with renal function. Early elimination of the exposure may, therefore, prevent the progress of renal failure in many patients.

Exposure to hydrocarbons and renal disease: an experimental animal model

The association between hydrocarbon exposure and chronic glomerulonephritis is still a controversial scientific issue. Recent epidemiological evidence suggests a role of exposure to hydrocarbons in the progression of glomerulonephritis towards chronic renal failure. The present experimental study on rats has been designed to assess the possible role of styrene in the progression of adriamycin (ADR) nephrosis, a well known model of renal fibrosis following nephrotic syndrome induced by ADR. Female Sprague-Dawley rats were exposed to styrene, 300 ppm, 6 h/day, 5 days/week for 12 weeks (group 1); treated with ADR, 2 mg/Kg, i.v., twice on day 1 and day 15 of the study (group 2); Additional groups of animals received both the styrene and ADR treatments (group 3) or served as controls (group 4). The urinary excretion of total and single proteins (albumin, Retinol-Binding Protein (RBP), Clara Cell 16 Kd protein (CC16), fibronectin) was measured monthly, whereas histopathology and determinations requiring blood sampling were carried out at the end of the experiment. A progressive increase in total proteinuria, falling in the nephrotic range already by the 6th week was observed in ADR-treated groups. Styrene exposure caused up to a 3- to 5-fold increase as compared to controls. Co-exposure to ADR and styrene also resulted in a proteinuria much greater than that caused by ADR alone. The interactive effect of styrene and ADR was statistically significant for albuminuria and urinary fibronectin. A similar response was observed for glomerular filtration rate at the end of the experiment, styrene-exposed animals showing hyperfiltration as compared to their respective control group. At the end of the experiment, histopathological scoring for interstitial infiltration and fibrosis was also significantly higher in styrene-treated animals as compared to their respective control groups. In ADR-treated rats, low molecular weight proteinuria (l.m.w.p.) was only slightly affected, suggesting minimal tubular dysfunction associated with extensive tubular atrophy. However, styrene-exposed animals showed l.m.w.p. higher than their respective controls. In summary, in this animal model we were able to confirm both styrene-induced microproteinuria, mainly albuminuria and minor increases in l.m.w.p., observed among occupationally exposed workers and the role of hydrocarbon exposure as a factor accelerating the progression of renal disease suggested by epidemiological investigations in patients suffering from chronic renal disease. Whereas in rats exposed to styrene only, microproteinuria was stable over time and minor histopathological changes were noted at the end of the experiment, evidence of a role of solvent exposure in the progression of ADR nephropathy was obtained in terms of both renal dysfunction and interstitial fibrosis. The mechanistic basis of styrene-ADR interaction is unclear. However, experimental evidence is consistent with epidemiological findings suggesting the need to avoid solvent exposure in patients suffering from renal diseases.

Occupational hydrocarbon exposure and chronic nephropathy

This review aims at discussing the questions raised by the hydrocarbon-related chronic nephropathy and its possible consequence, the hydrocarbon-related chronic renal failure. It has been attempted to adopt the point of view of the clinician. Therefore, the most important part of the review is devoted to a presentation and an analysis of the available data on humans. The main features of the available studies on human subjects are presented, their conclusions discussed in the light of the possible methodological flaws, and practical conclusions drawn. After a discussion of the main difficulties encountered for selecting the suitable exposure indicator, the studies are discussed in order of decreasing quality of the study design (cohort, case-control, cross-sectional studies, and the case reports). It is concluded that a great deal of controversies about chronic hydrocarbon-related nephropathy is explained by differences in the study design and that hydrocarbon-induced nephropathy is probably more than a mere hypothesis, although a causal relationship has not yet been proven. Finally, some practical consequences for dealing with a hydrocarbon-exposed patient diagnosed with a kidney disease and the need for further research are discussed.

Occupational factors and renal disease

The male-to-female ratio of patients requiring dialysis treatment commonly approaches 2:1. It is proposed that environmental factors, particularly occupational exposure to hydrocarbons, may account for the excess number of male patients. The term "hydrocarbon" refers to the aliphatic, alicyclic, aromatic, and halogenated hydrocarbons (carbon tetrachloride, chloroform); glycols (ethylene glycol, diethylene glycol, dioxane, glycerol); and organic solvents. Hydrocarbons commonly find use as solvents in industrial manufacturing practices because of their lipid solubility. Hydrocarbons have long been known to be neurotoxicants, affecting both peripheral and central nervous systems. Although benzene and its derivative have a known association with uroepithelial tumors, there is now a considerable body of evidence suggesting a possible role for hydrocarbon exposure in the development of non-neoplastic renal diseases. This article presents an epidemiological case for such an association and critically reviews the literature.

Renal and hepatic lesions induced by 2,2,4-trimethylpentane

The renal changes produced by 2,2,4-trimethylpentane, a constituent of unleaded gasoline, are studied in Wistar rats. The compound was given at a dose of 2 ml/kg daily by gavage dissolved in corn oil (2:1) to nine Wistar Albino rats. Nine control male rats received an equivalent dose of corn oil. Six animals were housed in metabowls to allow the collection of urine for enzyme and urinanalysis. The remaining three animals of each group were housed in a normal animal cage. After 2 days of treatment, all the test rats were noted to have lost weight and were killed on this or on the subsequent day. Macroscopic examination of the livers and kidneys revealed no visible lesions on the kidney, but two of the rats had white, slightly raised patches on the liver. Microscopic examination demonstrated centrilobular and confluent necrosis, hydropic degeneration and vacuolation of hepatocytes. Microscopic examination of the kidneys indicated eosinophilic hyaline droplet accumulation in the cells of the tubules, and tubular dilation. Analysis of plasma alkaline phosphatase and aspartate transaminase activity revealed increases consistent with liver damage. Analysis of urinary N-acetyl-beta-glucosaminidase and alkaline phosphatase activity showed increases consistent with renal toxicity. An apparent increase in the amount of cellular debris in the urine was also found, when the sediment was examined microscopically. From this study, it would appear that 2,2,4-trimethylpentane possess hepatotoxic as well as nephrotoxic properties.

Chemically induced renal papillary necrosis and upper urothelial carcinoma. Part 1

In the past, renal papillary necrosis (RPN) has been commonly associated with long-term abusive analgesic intake, but over recent years a wide variety of industrially and therapeutically used chemicals have been shown to induce this lesion experimentally or in man. Destruction of the renal papilla may result in: (1) secondary degenerative cortical changes which precede chronic renal failure or (2) a rapidly metastasizing upper urothelial carcinoma, which has a very poor prognosis. This article will briefly review the published data on the morphology, function, and biochemistry of the normal renal medulla and the pathology associated with RPN, together with the secondary changes which give rise to cortical degeneration or epithelial carcinoma. It will then examine in detail those chemicals which have been reported to cause RPN in an attempt to delineate structure-activity relationships. Finally, the many different theories that have been proposed to explain the pathophysiology of RPN will be examined and an hypothesis will be put forward to explain the primary pathogenesis of the lesion and its secondary consequences.

Chemically induced renal papillary necrosis and upper urothelial carcinoma. Part 2

In the past, renal papillary necrosis (RPN) has been commonly associated with long-term abusive analgesic intake, but over recent years a wide variety of industrially and therapeutically used chemicals have been shown to induce this lesion experimentally or in man. Destruction of the renal papilla may result in: (1) secondary degenerative cortical changes which precede chronic renal failure or (2) a rapidly metastasizing upper urothelial carcinoma, which has a very poor prognosis. This article will briefly review the published data on the morphology, function, and biochemistry of the normal renal medulla and the pathology associated with RPN, together with the secondary changes which give rise to cortical degeneration or epithelial carcinoma. It will then examine in detail those chemicals which have been reported to cause RPN in an attempt to delineate structure-activity relationships. Finally, the many different theories that have been proposed to explain the pathophysiology of RPN will be examined and an hypothesis will be put forward to explain the primary pathogenesis of the lesion and its secondary consequences.