Myocardial ultrastructure of rats fed high and low erucic acid rapeseed oils

Metabolomic profiling in dogs with dilated cardiomyopathy eating non-traditional or traditional diets and in healthy controls

Dilated cardiomyopathy (DCM), caused by genetic and environmental factors, usually progresses to heart failure, a major cause of death in elderly people. A diet-associated form of DCM was recently identified in pet dogs eating non-traditional (NT) diets. To identify potential dietary causes, we analyzed metabolomic signatures and gene set/pathway enrichment in (1) all dogs based on disease, diet, and their interactions and (2) dogs with DCM based on diet. Metabolomic analysis was performed in 38 dogs with DCM eating NT diets (DCM-NT), 8 dogs with DCM eating traditional diets, 12 healthy controls eating NT diets, and 17 healthy controls eating traditional diets. Overall, 153 and 63 metabolites differed significantly between dogs with DCM versus healthy controls and dogs eating NT versus traditional diets, respectively, with 12 metabolites overlapping both analyses. Protein-protein interaction networks and gene set enrichment analysis identified 105 significant pathways and gene sets including aging-related pathways (e.g., nuclear factor-kappa B, oxidative damage, inflammation). Seventeen metabolites differed significantly in dogs with DCM eating NT versus traditional diets (e.g., fatty acids, amino acids, legume biomarkers), suggesting different mechanisms for primary versus diet-associated DCM. Our multifaceted metabolomic assessment of DCM in dogs highlighted diet's role in some forms of DCM.

Ultrastructural and immunologic characteristics of mouse x cattle xenogeneic hybridomas originating from bovine leukemia virus-infected cattle

Nine percent of xenogeneic hybridomas originating from a bovine leukemia virus (BLV)-infected cow secreted monoclonal IgM antibodies with multispecific reactivity. Similar reactivity was evident in some antibodies with an unusually long (> 50 amino acids) third complementarity-determining region of the heavy chain. Electron microscopy of hybridomas demonstrated the presence of c-type virus particles consistent with polymerase chain reaction detection of BLV env gene. Some hybridomas contained dilated rough endoplasmic reticulum and cisternae filled with moderately electron-dense granular substance compatible with plasma cells at presecretory stage. The number of chromosomes in xenogeneic hybridomas corresponded to the sum total of mouse and bovine chromosomes. None of the hybridomas showed polyploidy. The immunochemical and genetic analysis of stable bovine immunoglobulin-secreting xenogeneic hybridomas confirms that BLV infection causes polyclonal B cell activation regardless of antigen specificity. Presence of c-type particles in hybridomas suggests that T cell-derived cytokines are not required for sustained BLV expression.

Effects of lipopolysaccharide-stimulated inflammation and pyrazole-mediated hepatocellular injury on mouse hepatic Cyp2a5 expression

Murine hepatic cytochrome P450 2a5 (Cyp2a5) is induced during hepatotoxicity and hepatitis, however, the specific regulatory mechanisms have not been determined. We compared the influence of acute inflammation elicited in vivo by bacterial endotoxin lipopolysaccharide (LPS) and liver injury caused by the hepatotoxin pyrazole on hepatic Cyp2a5 expression in mice. Pyrazole treatment resulted in statistically significant increases in levels of Cyp2a5 mRNA, protein and catalytic activity by 540, 273 and 711%, respectively (P<0.05). In LPS-treated livers Cyp2a5 expression was significantly reduced compared to controls at the mRNA (46%) protein (35%), and activity (23%) levels (P<0.05). Treatment of mice with recombinant murine interleukin-1 beta and interleukin-6 had no significant effect on Cyp2a5 mRNA and protein levels. Liver injury, as assessed by serum alanine aminotransferase, was greater with pyrazole than with LPS treatment (609 vs 354% of control levels respectively). ER stress, determined by hepatic glucose regulated protein 78 (grp78) levels, was greater with pyrazole (185% of controls) than with LPS (128% of controls). In pyrazole-treated liver, overexpression of immunoreactive grp78 protein revealed that ER stress was localized to pericentral hepatocytes in which Cyp2a5 was induced. Evidence of glycogen loss and membrane damage in these cells was suggestive of oxidative damage. Moreover, vitamin E attenuated Cyp2a5 induction by pyrazole in vivo. These results suggest that induction of Cyp2a5 that has been observed in mouse models of hepatitis and hepatoxicity may be related to oxidative injury to the endoplasmic reticulum of pericentral hepatocytes rather than exposure to pro-inflammatory cytokines.

Cardiac abnormalities in the toxic oil syndrome, with comparative observations on the eosinophilia-myalgia syndrome

Early in the course of studies of the Spanish toxic oil syndrome it was recognized that vascular lesions were a major problem, most logically attributable to endothelial damage by the toxic oil. However, most clinical attention has been directed to the pulmonary complications and the evolution into a scleroderma-like illness later. In this study of 11 victims of the toxic oil syndrome careful postmortem studies of the coronary arteries and conduction system and neural structures of the heart demonstrated major injury to all those components of the heart. Obliterative fibrosis of the sinus node in four cases resembled findings in fatal scleroderma heart disease, and in eight the cardiac lesions resembled those of lupus erythematosus. The more impressive pathologic features involved the coronary arteries and neural structures, which were abnormal in every heart. The arterial disease included widespread focal fibromuscular dysplasia, but there was also an unusual myointimal proliferative degeneration of both small and large coronary arteries in five patients, four of whom were young women. In two hearts, portions of the inner wall of the sinus node artery had actually detached and embolized downstream. Coronary arteritis was rarely found. Inflammatory and noninflammatory degeneration of cardiac nerves was widespread. Fatty infiltration, fibrosis and degeneration were present in the coronary chemoreceptor. In most respects these cardiac abnormalities resemble those described in the eosinophilia-myalgia syndrome caused by an altered form of L-tryptophan. In both diseases there is good reason to anticipate more clinical cardiac difficulties than have so far been reported, and even more basis for future concern, especially relative to coronary disease and cardiac electrical instability.

Histologic abnormalities of large and small coronary arteries, neural structures, and the conduction system of the heart found in postmortem studies of individuals dying from the toxic oil syndrome

Hundreds died and thousands were poisoned by rapeseed oil adulterated with aniline and sold illegally in Spain in 1981. The clinical manifestations, now known as the toxic oil syndrome, include pulmonary hypertension and right ventricular hypertrophy plus widespread vascular and neural lesions in other organs. Many of the late deaths ended with a scleroderma-like illness. Because scleroderma involves the heart, in this study we examined the small and large coronary arteries, neural structures, and conduction system from eight victims dying with the toxic oil syndrome. Dense fibrosis of the sinus node in two hearts resembled changes found in scleroderma. Atrionodal junctional hemorrhages and cystic degeneration of the sinus node present in the other six hearts resembled changes found in lupus erythematosus. Small and large coronary arteries exhibited focal fibromuscular dysplasia and a proliferative cystic myointimal degeneration. This latter abnormality was associated with sloughing of the inner wall and embolization of the detached fragment downstream in the same coronary artery. Every heart had many degenerative lesions within nerves, ganglia, and the coronary chemoreceptor. Both the arterial and neural abnormalities prominently involved the conduction system. Based upon observations by others with experimental feeding of rapeseed oil containing either high or low erucic acid, we suggest that this oil must remain a major suspected cause of the toxic oil syndrome, particularly in conjunction with some as yet unexplained facilitative influence by oleoanilids. If this is so, it is important to reconsider the widely recommended use of any rapeseed oil product as a suitable food for man or other animals.

Dietary factors affecting the incidence of dietary fat-induced myocardial lesions

Histological study of ventricular muscle was conducted on Sprague-Dawley male rats fed diets containing 20% (w/w) of either soybean oil, low erucic acid rapeseed oil or high erucic acid rapeseed oil. Purified diets providing two levels of intake for choline and inositol or magnesium were fed for 16 weeks to determine whether increased intake of these nutrients reduced myocardial lesion incidence. Diets containing high erucic acid rapeseed oil resulted in a high incidence of degenerative focal myocardial lesions, whereas low erucic acid rapeseed oil feeding resulted in less severe cardiopathological changes. Dietary supplementation providing 0.475% (w/w) choline and 0.635% (w/w) inositol reduced incidence of myocardial lesion for both rapeseed oil treatments indicating that lesion incidence may also be altered by the nutrient composition of the purified diet. Nutritional adaptation by increasing the animals dietary fat intake from 6% (w/w) to 20% (w/w) over an 8-week period had no effect on lesion incidence.