With the discovery of the prion protein (PrP), immunodiagnostic procedures were applied to diagnose Creutzfeldt-Jakob disease (CJD). Before development of the conformation-dependent immunoassay (CDI), all immunoassays for the disease-causing PrP isoform (PrP Sc ) used limited proteolysis to digest the precursor cellular PrP (PrP C ). Because the CDI is the only immunoassay that measures both the protease-resistant and protease-sensitive forms of PrP Sc , we used the CDI to diagnose human prion disease. The CDI gave a positive signal for PrP Sc in all 10 -24 brain regions (100%) examined from 28 CJD patients. A subset of 18 brain regions from 8 patients with sporadic CJD (sCJD) was examined by histology, immunohistochemistry (IHC), and the CDI. Three of the 18 regions (17%) were consistently positive by histology and 4 of 18 (22%) by IHC for the 8 sCJD patients. In contrast, the CDI was positive in all 18 regions (100%) for all 8 sCJD patients. In both gray and white matter, Ϸ90% of the total PrP Sc was protease-sensitive and, thus, would have been degraded by procedures using proteases to eliminate PrP C . Our findings argue that the CDI should be used to establish or rule out the diagnosis of prion disease when a small number of samples is available as is the case with brain biopsy. Moreover, IHC should not be used as the standard against which all other immunodiagnostic techniques are compared because an immunoassay, such as the CDI, is substantially more sensitive.
Diffusion-weighted (DWI) MRI is a highly sensitive and specific test for diagnosis of sporadic Jakob-Creutzfeldt disease (sCJD); however, the neuropathological origin of DWI signal abnormalities including other clinical features have not been well-defined. We describe a case of sCJD with brain MRI taken 15 days prior to death, which provided an opportunity to correlate clinical, EEG, MRI and neuropathological findings in order to better understand which sCJD-specific neuropathological changes underlie the DWI abnormalities. Clinical findings correlated well with both EEG and MRI changes. Neuropathological analysis showed that hyperintensities on DWI MRI correlated best with the vacuolation score (r=0.78, p=0.0005) and PrPSc load (r=0.77; p=0.0006), followed by reactive astrocytic gliosis (r=0.63, p=0.008). This case provides further evidence that DWI abnormalities correlate well with the clinical features and with PrPSc accumulation and vacuolation.
In prion-infected mice, both the Notch-1 intracellular domain transcription factor (NICD) and the disease-causing prion protein (PrP Sc ) increase in the brain preceding dendritic atrophy and loss. Because the drug LY411575 inhibits the ␥-secretase-catalyzed cleavage of Notch-1 that produces NICD, we asked whether this ␥-secretase inhibitor (GSI) might prevent dendritic degeneration in mice with scrapie. At 50 d postinoculation with Rocky Mountain Laboratory (RML) prions, mice were given GSI orally for 43-60 d. Because we did not expect GSI to produce a reduction of PrP Sc levels in brain, we added quinacrine (Qa) to the treatment regimen. Qa inhibits PrP Sc formation in cultured cells. The combination of GSI and Qa reduced PrP Sc by Ϸ95% in the neocortex and hippocampus but only Ϸ50% in the thalamus at the site of prion inoculation. The GSI plus Qa combination prevented dendritic atrophy and loss, but GSI alone did not. Even though GSI reduced NICD levels to a greater extent than GSI plus Qa, it was unable to prevent dendritic degeneration. Whether a balance between NICD and dendrite growth-stimulating factors was achieved with GSI plus Qa but not GSI alone remains to be determined. Although the combination of GSI and Qa diminished PrP Sc in the brains of RML-infected mice, GSI toxicity prevented us from being able to assess the effect the GSI plus Qa combination on incubation times. Whether less toxic GSIs can be used in place of LY411575 to prolong survival remains to be determined.Creutzfeldt-Jakob disease ͉ neuropathology ͉ prion disease ͉ therapy ͉ scrapie
Human prion diseases can be caused by mutations in the prion protein gene PRNP. Prion disease with mutations at codon 188 has been reported in 6 cases, but only 1 had the T188R mutation and it was not pathologically confirmed. We report the clinical, neuropsychological, imaging, genetic, and neuropathological features of a patient with familial Creutzfeldt-Jakob Disease (CJD), associated with a very rare PRNP mutation at T188R. The patient presented with prominent behavioral changes in addition to the more typical cognitive and motor impairments seen in sporadic CJD. The autopsy confirmed prion disease pathology. This case supports the pathogenicity of the T188 PRNP mutation, demonstrates the variability of clinical phenotypes associated with certain mutations and emphasizes the importance of testing for genetic prion disease in cases of apparently sporadic atypical dementia.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.