Creutzfeldt-Jakob disease

The historical aspects of spongiform encephalopathies, Creutzfeldt-Jakob disease (CJD) and kuru of man, as well as scrapie and transmissible mink encephalopathy, are outlined. Transmissions of these diseases to animal hosts are presented, with emphasis on CJD transmissions to guinea pigs, hamsters, and mice. The relationship of CJD to scrapie with reference to the pathological findings is discussed. In CJD the incubation period is cut in half in guinea pigs and hamsters in the second passage. The spongiform changes occurring in the neuropil are reviewed. These changes are related to the type of inoculum, e.g., there is more vacuolization after inoculation with brain, and less after inoculation with spleen. Spongiform changes are also dependent upon the route of inoculation; these are more severe in intracerebral inoculation compared to intraperitoneal inoculation. Viremia is present. Maternal transmission and lateral transmission are absent. No virus-like particles are detected, and no other organisms are visible by electron microscopy. Isolations of the causative agent and strains of the agent in spongiform encephalopathies remain elusive. The hypotheses concerning the nature of the agent are critically reviewed. Novel data on the production of tumors derived from CJD brains are presented. Tissue culture cells arising from such brains become permanent lines and are similar to neoplastic lines. When such CJD lines are injected subcutaneously into nude mice, malignant neoplasms are formed. No evidence of an infectious etiology in Alzheimer's disease exists. Reported similarities between this disease and CJD are reviewed. Animal models of CJD are useful for the investigation of dementias.     

Appearance of tubulovesicular structures in experimental Creutzfeldt-Jakob disease and scrapie preceeds the onset of clinical disease

Summary We have consistently observed tubulovesicular structures in brain tissues during the terminal stages of naturally occurring and experimentally induced spongiform encephalopathies, irrespective of the host species and virus strain. In NIH Swiss mice inoculated intracerebrally or intraocularly with the Fujisaki strain of Creutzfeldt-Jakob disease (CJD) virus, tubulovesicular structures, measuring 20–50 nm in diameter, were particularly prominent in dilated, pre-and postsynaptic neuronal processes, occasionally being mixed with synaptic vesicles. These structures appeared 13 weeks following intracerebral inoculation, 5 weeks before the onset of clinical signs, when spongiform changes were also detected. The number and density of tubulovesicular structures increased steadily during the course of clinical disease, and were particularly abundant in mice 47 to 51 weeks after intraocular inoculation. In hamsters infected with the 263 K strain of scrapie virus, these structures were initially detected 3 weeks following intracerebral inoculation and increased dramatically at 10 weeks postinoculation. The appearance of tubulovesicular structures before the onset of overt disease in mice inoculated with CJD virus by either the intracerebral or intraocular route, and before the appearance of other neuropathological changes in hamsters infected with scrapie virus, indicate that they represent either a part or aggregate of the infectious virus or a pathological product of the infection.Presented in part at the 64th annual meeting of the American Association of Neuropathologists, held in Charleston, South Carolina, June 9–12, 1988 and at the 7th annual meeting of the American Society for Virology, Austin, Texas, June 12–16, 1988. Dr. Pawel P. Liberski is a recipient of a fellowship from the Fogarty International Center and a grant from the Ministry of Health and Social Welfare, Poland     

Experimental transmission of human subacute spongiform encephalopathy to small rodents

Summary Experimental transmission of subacute spongiform encephalopathy from three human cases to small rodents is reported. The first case with atypical CJD with spongiform change, kuru plaques, and leukomalacia was transmitted directly to mice, rats, and guinea pigs and indirectly to hamsters and Mongolian gerbils through rats. From two other typical SSE cases the disease was also successfully transmitted; from the second case to mice and rats, and from the third case to guinea pigs. Brain showed the highest infectivity; the spleen, liver, blood, and cerebrospinal fluid of diseased animals were also infective. Intracerebral inoculation was the route for the fastest transmission, followed by intrathecal, intraperitoneal, submucosal, and subcutaneous routes. The incubation periods and clinical features were characteristic in each inoculated species and did not vary within several passages, except for the shortening of incubation period from the first to the second passage. Histologically, a marked spongy state and proliferation of astrocytes were observed in all diseased animals, though the distribution of the lesion was peculiar to each species. The severe lesion in the white matter in mice was similar to that seen in mice inoculated with scrapie and also to that seen in the first case.     

Deposition of the prion protein (PrP) during the evolution of experimental Creutzfeldt-Jakob disease

We studied the immunocytochemical distribution of the prion or proteinase-resistant protein (PrP) during the evolution of experimental Creutzfeldt-Jakob disease (CJD) in mice. Fifty-one brains were collected up to 22 weeks following intracerebral inoculation with the Fujisaki strain of the CJD agent. Slides were also immunostained for apolipoprotein E (apoE) and glial fibrillary acidic protein. Vacuolar changes with focal astrocytosis first occurred around the needle track at week 2 and later spread along white matter tracks. Until week 12, changes were asymmetrical, affecting more the side of inoculation. Spongiform change and astrogliosis spread subsequently to the gray matter. Time course and intensity of spongiform change and immunocytochemistry for PrP were discrepant: in most brain regions, severe vacuolation preceded immunocytochemically detectable PrP accumulation. PrP deposits in form of small dots were first detectable at week 6 in the area surrounding the needle track. After week 7, plaque-like amorphous PrP deposits were observed in white matter pathways. Finally, PrP was detectable also in basal ganglia and in the dorsal hippocampus (week 13) and in the neocortex (week 17), as the synaptic type of PrP immunopositivity. In the hippocampus, diffuse PrP deposits paralleled spongiform change, while in the cortex severe vacuolation was accompanied only by weak synaptic PrP deposits. Immunocytochemically detectable apoE was restricted to compact plaque-type PrP deposits after week 15. We conclude that disease-specific neuropathology spreads from the needle track along white matter pathways towards the gray matter; in this model, there is some discrepancy between development of tissue pathology and immunocytochemically detectable deposition of PrP. Immunocytochemically detectable apoE deposition follows PrP accumulation. Received: 22 December 1998 / Revised, accepted: 6 April 1999     

Comparison of spongiform lesions in experimental scrapie and rabies in skunks

Summary Striped skunks were inoculated intracerebrally with the scrapie agent (suspension of brain from a naturally infected Suffolk sheep) or intramuscularly with street rabies virus (suspension of salivary glands from naturally infected skunks). Those given the scrapie agent developed clinical signs of weakness, posterior ataxia, and emaciation after incubation periods of 8 to 23 months. Those inoculated with rabies virus developed clinical signs of rabies (aggressive behavior, hyperexcitability, ataxia and paralysis) after incubation periods of 20 to 62 days. The gross lesions in the brains of the skunks given the scrapie agent consisted of marked atrophy of the thalamus and moderate atrophy of the cerebrum. No gross lesions occurred in the rabid skunks. Histologically, the type of spongiform lesion in rabies was the same as that in scrapie. However, spongiform change of rabies infected brains was less extensive (only rarely affected the basal ganglia, hippocampus or hypothalamus) than that of brains infected with the scrapie agent and was characterized by fewer numbers of small vacuoles (as a proportion of total number of vacuoles) than occurred in scrapie spongiform change.     

Creutzfeldt-Jakob disease with tubulovesicular structures: an ultrastructural study.

Tubulovesicular structures (TVS) have been consistently observed in brain tissue of the transmissible spongiform virus encephalopathies such as natural and experimental scrapie, bovine spongiform encephalopathy and experimentally induced Creutzfeldt-Jakob disease (CJD). TVS were recently demonstrated in 3 cases of naturally occurring CJD. We report here the presence of TVS in another human brain with CJD, as detected in all 3 specimens by thin section electron microscopy. Their occurrence in all types of spongiform encephalopathies, irrespective of the affected host and the strain of infectious agent, emphasizes their biological significance.     

Transmissible virus dementia: evaluation of a zoonotic hypothesis

Creutzfeldt-Jakob disease (CJD) and kuru are subacute transmissible dementing encephalopathies characterized by spongiform changes in the brain. Scrapie is a similar slow viral encephalopathy which affects sheep, goats and certain other animals. Anecdotal reports suggest that Creutzfeldt-Jakob disease could be a zoonosis. To evaluate the possibility that CJD is acquired from animals, a case-control study was conducted on 26 well-documented CJD cases and 40 controls. Data were collected on exposure to animals through occupations, hobbies, sports and pets. An excess exposure to certain animals was noted among the patients compared to controls in relation to occupation (deer, monkey, squirrel; odds ratio (OR) = 8.9; p less than 0.10) and hobbies (deer, OR = 9.0; rabbit, OR = 6.0; p less than 0.05). Similarly, exposure to animal organs was significantly greater in the CJD group (OR = 20.9; p less than 0.005). Statistically significant increased exposure to sheep or goats was not found among the patients. However, since spongiform encephalopathy has a wider host range than sheep and goats, the increased exposure to certain other animals suggests that a zoonotic source for CJD should be further explored.     

Experimental transmission of human subacute spongiform encephalopathy to small rodents

Summary Further experimental transmission of Creutzfeldt-Jakob disease (CJD) from three patients to mice and rats was carried out successfully. The clinical signs and pathologic features of spongiform encephalopathy transmitted to animals were much the same as in previous experiments, except that distribution of the lesions in the mice differed with each inoculated material taken from the patients. These observations suggest the multiplicity of CJD agents, as in the case of scrapie agents.     

How do neurons degenerate in transmissible spongiform encephalopathies?

Neuroaxonal dystrophy is a feature of neuronal degeneration encountered in all subacute spongiform virus encephalopathies including scrapie and Creutzfeldt-Jakob disease (CJD). By immunohistochemical techniques, the accumulation of 200 kDa neurofilament protein was demonstrated in affected neurites in human CJD. These neurites exhibited the ultrastructural features of dystrophic neurites encountered in other neurodegenerative disorders, particularly Alzheimer's disease. These findings support the hypothesis that impairment of slow axoplasmic transport is a common pathogenetic mechanism for CJD and many other neurodegenerative conditions.     

How do neurons degenerate in transmissible spongiform encephalopathies?

Neuroaxonal dystrophy is a feature of neuronal degeneration encountered in all subacute spongiform virus encephalopathies including scrapie and Creutzfeldt-Jakob disease (CJD). By immunohistochemical techniques, the accumulation of 200 kDa neurofilament protein was demonstrated in affected neurites in human CJD. These neurites exhibited the ultrastructural features of dystrophic neurites encountered in other neurodegenerative disorders, particularly Alzheimer's disease. These findings support the hypothesis that impairment of slow axoplasmic transport is a common pathogenetic mechanism for CJD and many other neurodegenerative conditions.     

Spongiform encephalopathy in mice inoculated with scrapie material of sheep origin

The authors report spongy degeneration in experimental scrapie (second passage) in mice. The scrapie agent was originally isolated from Suffolk sheep imported from Canada and diagnosed histopathologically to be infected with scrapie by intracerebral inoculation into JCL/ICR mice. Ten female SIc/ICR mice, 4 weeks of age, were injected intracerebrally in the right frontal lobus with 20 microliter of 10(-1) or 10(-4) dilution of JCR/ICR mice brain homogenate involving scrapie agent. All animals showed signs of the advanced stages of the disease, clinically manifested by lassitude, arched backs, lethargy and paresis of hind quarters. They were sacrificed five to six months post inoculation, and sections of the brain and spinal cord were examined by light and electron microscopy. Focal symmetrical spongiform lesions were seen light microscopically in the cerebral mantle, thalamus, hypothalamus, midbrain, medulla oblongata, cerebellum and cervical mark. There was evidence that these lesions tended to be more intense in the mice inoculated a higher concentration of scrapie agent. Astrocytic proliferation was present in the deep layer of cerebral gray matter, white matter, corpus callosum, dorsal part of hippocampus and thalamus. No leukocytic infiltration was observed. Electron microscopically, the spongiform lesions were shown to be caused by vacuolation or swelling within the neuropil, and vacuolation and focal swelling in the neuronal perikaryon. The changes in the neuronal perikaryon were caused by enlargement of endoplasmic reticulum and cisterns of the Golgi apparatus, accompanied by spherical swelling of a part of the cytoplasm. The vacuolation near or within the neuron produced deformation of the cell contours and displacement of the nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in tyrosine hydroxylase, glutamic acid decar☐ylase and choline acetyltransferase after local microinoculation of scrapie agent into the nigrostriatal system of the golden hamster

A microinjection of a homogenate of scrapie agent-infected brain (strain 263 K) into the nigrostriatal system in the golden hamster is followed by the progressive development of the disease which terminates by the death of animals around the 4th month postinoculation. These intracerebral inoculations induce more rapid changes in neuronal activity which can be revealed by the assessment of the specific synthesizing enzymes of neurotransmitter systems. The microinoculation of a homogenate of an infected brain unilaterally into the substantia nigra (SN) provokes a decrease in tyrosine hydroxylase (TH), the synthesizing enzyme for dopamine in the dopaminergic neurones, in the striatum ipsilateral to the injected SN. This biochemical response, specifically induced by the active pathogen, is detectable as soon as the 5th day postinoculation and is detectable towards the 80th day. A return of TH levels to control values is detected after this period. At the end of the incubation period and towards the death of the animals, TH is not different from control TH measured from intact animals. The decrease in TH is concomitant with an increase in striatal glutamic acid decar☐ylase (GAD), the synthesizing enzyme for γ-aminobutyric acid (GABA), measured 20 days postinoculation with no change in choline acetyltransferase (ChAT), the synthesizing enzyme for acetylcholine. Studies of the biochemical responses associated locally to the scrapie agent inoculation have been performed at the striatal level. The intrastriatal administration of the infective agent induces 20 days postinoculation an increase in GAD with no change in TH and ChAT. Ninety days postinoculation, a decrease in GAD was detected associated with an increase in TH with no change in ChAT. The decrease in striatal TH 5 days after inoculation of the scrapie agent in the ipsilateral SN represents in the hamster an early marker of the slow progressive pathologic process which can only be revealed about 80 days postinoculation. The influence of the pathogen in the nigrostriatal system could be specific for certain categories of neurones. The cholinergic neurones are apparently not affected. The dopaminergic neurones seem not to be permanently damaged, as seen by the return of TH to control values during the development of the disease. The GABAergic neurones could represent a preferential target for the pathogen as shown by the early GAD activation and tardive decrease activity.     

Prion protein immunohistochemical staining in the brains of monkeys with transmissible spongiform encephalopathy

Prion protein (PrP) immunohistochemical staining of the brains of common marmosets (Callithrix jacchus) with experimental transmissible spongiform encephalopathy is described. The monkeys ( n =17) had been injected, intracerebrally, 17–49  months previously with homogenates of brain tissue taken post mortem from a cow with BSE ( n =2 monkeys), a sheep with natural scrapie ( n =2 monkeys), human cases of growth hormone related Creutzfeldt–Jakob disease (CJD) ( n =2 monkeys), sporadic CJD ( n =5 monkeys), or Gerstmann–Sträussler–Scheinker disease (GSS) ( n =4 monkeys), or from monkeys with spongiform encephalopathy resulting from injection with brain tissue from these last two cases ( n =1 monkey from each case). Only diffuse PrP-staining was seen in monkeys injected with CJD-material whereas more aggregated deposits of PrP were seen in monkeys injected with BSE-, scrapie-and GSS-brain tissue. There were no patterns of staining specific to the brains injected with BSE-material that could be used to identify the origin of that inoculum. BSE-and scrapie-injected monkey brains could be distinguished from each other because in BSE-injected monkey brain the spongiform vacuolation was largely confined to subcortical structures whereas in scrapie-injected monkey brain the spongiform vacuolation was also prominent in the neocortex. The patterns of PrP deposition differed markedly between those seen in monkey brains injected with BSE-material or CJD-material, but the patterns of PrP staining seen in monkey brains injected with BSE-material were also seen in monkey brains injected with scrapie-or GSS-material. Overall there was a correlation between the length of the incubation period and the amount of aggregated PrP-staining, but no correlation between the neuropathological picture and the clinical presentation of neurological signs.     

Experimental panencephalitis induced in suckling mice by parainfluenza type 1 (6/94) virus. I. Clinical and pathological features.

Intracerebral inoculation of two strains of suckling mice with 6/94 virus, a parainfluenza type 1 virus originally isolated from two patients with multiple sclerosis, produced clinical disease 1-2 weeks after inoculation. Of 528 animals inoculated, 33% died (26% of the ICR strain and 76% of the BALB/c strain) usually between two or three weeks after injection. Animals that recovered appeared to develop normally. Pathological changes were of two types. Initially, there was a necrotizing panencephalitis with virus-specific intracytoplasmic inclusions in choroid and ependymal epithelial cells and neurons. The second major lesion appeared about 6 weeks post inoculation and consisted of a noninflammatory spongiform degeneration of white matter that primarily involved the cerebral hemispheres; a diffuse vacuolar encephalapathy primarily affecting the brain stem; and a persistent minimal inflammation.     

Notes on the history of the prion diseases. Part II

The protein-only theory of transmission of the prion diseases remains controversial. Other mechanisms such as the virus, virino, and viroid hypotheses are still under consideration. All these fit in the concept of 'slow' infections that had been proposed in 1954 by Bjorn Sigurdsson, an Icelandic pathologist. Regardless of the exact mode of infection, the presence of prions in the brain has served to unite Creutzfeldt-Jakob disease (CJD), the Gerstmann-Str?ussler-Scheinker syndrome and fatal familial insomnia, as well as scrapie and a number of other animal diseases, into a single pathological entity, the transmissible spongiform encephalopathies. The appearance of bovine spongiform encephalopathy in the United Kingdom and its putative relationship to new variant CJD, have put a new and unpredictable light on these unusual and uncommon diseases.     

Transmission of Alpers' disease (chronic progressive encephalopathy) produces experimental Creutzfeldt-Jakob disease in hamsters

We successfully and serially transmitted to outbred and inbred strains of hamsters the brain tissue of a 2 1/2-year-old girl with a chronic progressive encephalopathy (Alpers' disease) characterized postmortem as a spongiform encephalopathy. In all hamster strains we produced a spongiform encephalopathy. The light and ultrastructural changes in the brain of hamsters, as well as the clinical signs of experimental disease, are identical to those obtained in transmission experiments of human Creutzfeldt-Jakob disease (CJD). CJD infection may be more widespread than previously recognized and can be manifested in infancy.     

Sheep consumption: a possible source of spongiform encephalopathy in humans

A fatal spongiform encephalopathy of sheep and goats (scrapie) shares many characteristics with Creutzfeldt-Jakob disease (CJD), a similar dementing illness of humans. To investigate the possibility that CJD is acquired by ingestion of contaminated sheep products, we collected information on production, slaughtering practices, and marketing of sheep in Pennsylvania. The study revealed that sheep were usually marketed before central nervous system signs of scrapie are expected to appear; breeds known to be susceptible to the disease were the most common breeds raised in the area; sheep were imported from other states including those with a high frequency of scrapie; use of veterinary services on the sheep farms investigated and, hence, opportunities to detect the disease were limited; sheep producers in the area knew little about scrapie despite the fact that the disease has been reported in the area, and animal organs including sheep organs were sometimes included in processed food. Therefore, it was concluded that in Pennsylvania there are some 'weak links' through which scrapie-infected animals could contaminate human food, and that consumption of these foods could perhaps account for spongiform encephalopathy in humans. The weak links observed are probably not unique to Pennsylvania.     

Immunoblotting of Creutzfeldt-Jakob disease prion proteins: host species-specific epitopes

Creutzfeldt-Jakob disease (CJD) is a rare dementia that is generally found in older people and is caused by unusual infectious pathogens or prions. Using rabbit antisera raised against hamster scrapie prion proteins (HaPrPSc), we identified by immunoblotting human CJD prion proteins (HuPrPCJD) in the brains of 14 patients dying of CJD. Extracts from 6 of the patients were transmitted to mice after prolonged incubation. The rabbit antisera raised against HaPrPSc also reacted with the mouse CJD prion proteins (MoPrPCJD) found in the brains of these experimentally infected mice. When mice were immunized with HuPrPCJD, they produced antibodies that reacted with HuPrPCJD but not with MoPrPCJD. Mice immunized with MoPrPCJD produced antibodies to neither murine nor human prion proteins. Our results provide evidence for host species-specific epitopes on prion proteins. The existence of such epitopes is consistent with the apparent lack of an immune response during prion infections and the finding that prion protein molecules are encoded by host genes.     

Neuronal loss and apoptosis in experimental Creutzfeldt-Jakob disease in mice

One of the hallmarks of prion disease--neuronal cell loss, may be accomplished by apoptosis. The aim of this study was to estimate the neuronal cell loss in mice brains with experimental Creutzfeldt-Jakob disease (CJD) and control mice in the comparison with the apoptosis appeared by in situ end labelling (TUNEL) in function of time of post-incubation period and developing of the spongiform changes. The number of neurons was considerably lower in terminally sick animals (20-21 week of incubation period) than in control mice. The mean value of loss of neuronal cell was 32%. The greatest loss (55%) of neurons was noted in the septal nuclei of the paraterminal body and the least lost (16%) in the hypothalamus. We report here, that apoptotic cells are readily detectable in CJD-affected mice brains in time-dependt manner after infection of Fujisaki strain, but the number of apoptotic cells detected by in situ end labelling does not well correlate with the extensiveness of neuronal loss. The degree of apoptosis corresponds to the well developed spongiform changes.     

Vacuolar change in Alzheimer's disease

A retrospective neuropathologic study of brains from 66 patients with Alzheimer's disease (AD) demonstrated the presence of a vacuolar change (VC) in 50 cases that was virtually indistinguishable histologically from the spongiform change characteristic of Creutzfeldt-Jakob disease (CJD). Indeed, in several instances, there was initial diagnostic confusion with CJD. Unlike the spongiform change in CJD, however, VC was almost entirely restricted to the medial temporal cortex and amygdala. Furthermore, the severity of VC was usually less intense than the spongiform change observed in cases of CJD with severe neurologic impairment. The VC could be readily distinguished from the fine microvacuolation of the upper layers of the isocortex reported in a number of different conditions, including AD. It also differed from the status spongiosus of the cerebral cortex that occurs in advanced AD and CJD as well as in other degenerative diseases. The artifactual rarefaction that occurs in improperly processed paraffin-embedded brain tissue was excluded as a contributory factor to the VC. Since VC does not invariably occur in AD, it conceivably could represent a subtype of this disorder or may represent a variant of the pathologic changes that can occur. Its relationship to CJD or other slow virus disorders is to date unknown but unlikely.