Comparative Neuropathology of Ovine Enterotoxemia Produced by Clostridium perfringens Type D Wild-Type Strain CN1020 and Its Genetically Modified Derivatives

Abstract

Clostridium perfringens type D causes enterotoxemia in sheep and goats. The disease is mediated by epsilon toxin (ETX), which affects the cerebrovascular endothelium, increasing vascular permeability and leading to cerebral edema. In the present study, we compared the distribution and severity of the cerebrovascular changes induced in lambs by C. perfringens type D strain CN1020, its isogenic etx null mutant, and the ETX-producing complemented mutant. We also applied histochemical and immunohistochemical markers to further characterize the brain lesions induced by ETX. Both ETX-producing strains induced extensive cerebrovascular damage that did not differ significantly between each other in nature, neuroanatomic distribution, or severity. By contrast, lambs inoculated with the etx mutant or sterile, nontoxic culture medium did not develop detectable brain lesions, confirming that the neuropathologic effects observed in these infections are dependent on ETX production. Lambs treated with the wild-type and complemented strains showed perivascular and mural vascular edema, as well as serum albumin extravasation, particularly severe in the cerebral white matter, midbrain, medulla oblongata, and cerebellum. Brains of animals inoculated with the ETX-producing strains showed decreased expression of glial fibrillary acidic protein and increased expression of aquaporin-4 in the end-feet processes of the astrocytes around blood vessels. Early axonal injury was demonstrated with anti-amyloid precursor protein immunohistochemistry. Perivascular accumulation of macrophages/microglia with intracytoplasmic albumin globules was also observed in these animals. This study demonstrates that ETX is responsible for the major cerebrovascular changes in C. perfringens type D-induced disease.

Histological assessment of β‐amyloid precursor protein immunolabelled rectal biopsies aids diagnosis of equine grass sickness

“…Consistent with the latter two hypotheses, ultrastructural loss of a recognisable Golgi structure is a likely early event in EGS, and EGS is associated with major perturbations in the cytoskeleton of autonomic neurons that result in the accumulation of dopamineb-hydroxylase and presynaptic proteins in neuronal perikarya [19,27,28]. b-APP has been described as a marker of early axonal injury prior to apparent histological changes in routine H&E-stained sections [29].…”

Clostridium perfringens Epsilon Toxin Causes Selective Death of Mature Oligodendrocytes and Central Nervous System Demyelination

“…The CNS manifestations of C. perfringens type D-mediated disease are wholly dependent on ε-toxin, since targeted loss of function of the ε-toxin gene renders the organism incapable of causing CNS pathology, and restoration of a functional ε-toxin gene reestablishes the CNS phenotype (6, 7). …”

Animal models to study the pathogenesis of human and animal Clostridium perfringens infections

“…Recently, it has also been demonstrated that the rabbit colon is also sensitive to the action of purified CPE, with both fluid secretion and mucosal damage observed (Garcia et al, 2014). The histological changes caused by CPE in both small intestinal and colonic loops of rabbits consist mainly of mucosal necrosis and hemorrhage.…”

“…The histological changes caused by CPE in both small intestinal and colonic loops of rabbits consist mainly of mucosal necrosis and hemorrhage. These changes are both time- and dose-dependent (Duncan et al, 1968; McDonel and Duncan, 1975, Smedley 3 rd et al, 2008; Garcia et al, 2014) and begin at villus tips in small intestinal loops (McDonel and Duncan, 1975, Sherman et al, 1994), where there is a greater density of claudin 4 (Smedley 3 rd et al, 2008). Rabbits have also been used to study the binding of CPE to extraintestinal tissues, which led to the demonstration that this toxin binds to liver and kidney (McDonel, 1980), a finding that might explain systemic changes in patients with enterotoxigenic C. perfringens type A-associated disease.…”

“…The most significant effects of ETX are edema of the lungs and brain. It has also been demonstrated that rats and sheep intoxicated with ETX, suffer upregulation of aquaporine 4 (a membrane water-channel proteins) in the brain (Finnie et al, 2008; Garcia et al, 2014). A mutant with cysteine substitutions in the membrane insertion domain of ETX has been tested in a mouse model.…”