Temporal evolution of sporadic Creutzfeldt–Jakob disease monitored by 3-Tesla MR spectroscopy

Cellular prion protein directly interacts with and enhances lactate dehydrogenase expression under hypoxic conditions

Although a physiological function of the cellular prion protein (PrP(c)) is still not fully clarified, a PrP(c)-mediated neuroprotection against hypoxic/ischemic insult is intriguing. After ischemic stroke prion protein knockout mice (Prnp(0/0)) display significantly greater lesions as compared to wild-type (WT) mice. Earlier reports suggested an interaction between the glycolytic enzyme lactate dehydrogenase (LDH) and PrP(c). Since hypoxic environment enhances LDH expression levels and compels neurons to rely on lactate as an additional oxidative substrate for energy metabolism, we examined possible differences in LDH protein expression in WT and Prnp(0/0) knockout models under normoxic/hypoxic conditions in vitro and in vivo, as well as in a HEK293 cell line. While no differences are observed under normoxic conditions, LDH expression is markedly increased after 60-min and 90-min of hypoxia in WT vs. Prnp(0/0) primary cortical neurons with concurrent less hypoxia-induced damage in the former group. Likewise, cerebral ischemia significantly increases LDH levels in WT vs. Prnp(0/0) mice with accompanying smaller lesions in the WT group. HEK293 cells overexpressing PrP(c) show significantly higher LDH expression/activity following 90-min of hypoxia as compared to control cells. Moreover, a cytoplasmic co-localization of LDH and PrP(c) was recorded under both normoxic and hypoxic conditions. Interestingly, an expression of monocarboxylate transporter 1, responsible for cellular lactate uptake, increases with PrP(c)-overexpression under normoxic conditions. Our data suggest LDH as a direct PrP(c) interactor with possible physiological relevance under low oxygen conditions.

Dementia and neuroimaging

Early diagnosis of dementing conditions and an accurate monitoring of their progression are important clinical and research goals, especially given the improving prospects of disease-modifying therapies. Neuroimaging has played and is playing an important role in detecting reversible, treatable causes of dementia, and in characterizing the dementia syndromes by demonstrating structural and functional signatures that can aid in their differentiation. Many new imaging techniques and modalities are also available that allow the assessment of specific aspects of brain structure and function, such as positron emission tomography with new ligands, diffusion tensor magnetic resonance imaging (MRI) and functional MRI. In this review, we report the most recent findings from the papers published in the Journal of Neurology that used conventional and advanced neuroimaging techniques for the study of various dementing conditions.