The majority of metabolic principles are evolutionarily conserved from nematodes to humans. Caenorhabditis elegans has widely accelerated the discovery of new genes important to maintain organismic ...metabolic homeostasis. Various methods exist to assess the metabolic state in worms, yet they often require large animal numbers and tend to be performed as bulk analyses of whole worm homogenates, thereby largely precluding a detailed studies of metabolic changes in specific worm tissues. Here, we have adapted well-established histochemical methods for the use on C. elegans fresh frozen sections and demonstrate their validity for analyses of morphological and metabolic changes on tissue level in wild type and various mutant strains. We show how the worm presents on hematoxylin and eosin (H&E) stained sections and demonstrate their usefulness in monitoring and the identification of morphological abnormalities. In addition, we demonstrate how Oil-Red-O staining on frozen worm cross-sections permits quantification of lipid storage, avoiding the artifact-prone fixation and permeabilization procedures of traditional whole-mount protocols. We also adjusted standard enzymatic stains for respiratory chain subunits (NADH, SDH, and COX) to monitor metabolic states of various C. elegans tissues. In summary, the protocols presented here provide technical guidance to obtain robust, reproducible and quantifiable tissue-specific data on worm morphology as well as carbohydrate, lipid and mitochondrial energy metabolism that cannot be obtained through traditional biochemical bulk analyses of worm homogenates. Furthermore, analysis of worm cross-sections overcomes the common problem with quantification in three-dimensional whole-mount specimens.
Aims
Coronavirus disease 2019 (COVID‐19), caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has rapidly evolved into a sweeping pandemic. Its major manifestation is in the ...respiratory tract, and the general extent of organ involvement and the microscopic changes in the lungs remain insufficiently characterised. Autopsies are essential to elucidate COVID‐19‐associated organ alterations.
Methods and results
This article reports the autopsy findings of 21 COVID‐19 patients hospitalised at the University Hospital Basel and at the Cantonal Hospital Baselland, Switzerland. An in‐corpore technique was performed to ensure optimal staff safety. The primary cause of death was respiratory failure with exudative diffuse alveolar damage and massive capillary congestion, often accompanied by microthrombi despite anticoagulation. Ten cases showed superimposed bronchopneumonia. Further findings included pulmonary embolism (n = 4), alveolar haemorrhage (n = 3), and vasculitis (n = 1). Pathologies in other organ systems were predominantly attributable to shock; three patients showed signs of generalised and five of pulmonary thrombotic microangiopathy. Six patients were diagnosed with senile cardiac amyloidosis upon autopsy. Most patients suffered from one or more comorbidities (hypertension, obesity, cardiovascular diseases, and diabetes mellitus). Additionally, there was an overall predominance of males and individuals with blood group A (81% and 65%, respectively). All relevant histological slides are linked as open‐source scans in supplementary files.
Conclusions
This study provides an overview of postmortem findings in COVID‐19 cases, implying that hypertensive, elderly, obese, male individuals with severe cardiovascular comorbidities as well as those with blood group A may have a lower threshold of tolerance for COVID‐19. This provides a pathophysiological explanation for higher mortality rates among these patients.
The structural complexity of chromosome 1p centromeric region has been an obstacle for fine mapping of tumor suppressor genes in this area. Loss of heterozygosity (LOH) on chromosome 1p is associated ...with the longer survival of oligodendroglioma (OD) patients. To test the clinical relevance of 1p loss in glioblastomas (GBM) patients and identifiy the underlying tumor suppressor locus, we constructed a somatic deletion map on chromosome 1p in 26 OG and 118 GBM. Deletion hotspots at 4 microsatellite markers located at 1p36.3, 1p36.1, 1p22 and 1p11 defined 10 distinct haplotypes that were related to patient survival. We found that loss of 1p centromeric marker D1S2696 within NOTCH2 intron 12 was associated with favorable prognosis in OD (P = 0.0007) as well as in GBM (P = 0.0175), while 19q loss, concomitant with 1p LOH in OD, had no influence on GBM survival (P = 0.918). Assessment of the intra-chromosomal ratio between NOTCH2 and its 1q21 pericentric duplication N2N (N2/N2N-test) allowed delineation of a consistent centromeric breakpoint in OD that also contained a minimally lost area in GBM. OD and GBM showed distinct deletion patterns that converged to the NOTCH2 gene in both glioma subtypes. Moreover, the N2/N2N-test disclosed homozygous deletions of NOTCH2 in primary OD. The N2/N2N test distinguished OD from GBM with a specificity of 100% and a sensitivity of 97%. Combined assessment of NOTCH2 genetic markers D1S2696 and N2/N2N predicted 24-month survival with an accuracy (0.925) that is equivalent to histological classification combined with the D1S2696 status (0.954) and higher than current genetic evaluation by 1p/19q LOH (0.762). Our data propose NOTCH2 as a powerful new molecular test to detect prognostically favorable gliomas.
Filaments made of hyperphosphorylated tau protein are encountered in a group of neurodegenerative disorders termed tauopathies. The most prevalent tauopathy, Alzheimer's disease (AD), additionally ...presents with extracellular deposits of the amyloid-β peptide (Aβ). Current symptomatic treatments have shown short term benefits in reducing cognitive symptoms as well as behavioral abnormalities in patients with mild to moderate AD but there is still no effective treatment to prevent or reverse AD. For decades, the amyloid cascade hypothesis of AD dominated basic research and focused pharmaceutical interest on Aβ. However, the existence of tauopathies that are devoid of Aβ deposits, together with the discovery of mutations in the tau gene leading to frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17T), confirmed the importance of tau per se in disease. Tau became an interesting disease target in its own right. We will review here recent research on cell-to-cell propagation of tau pathology, which we believe to be central to disease progression, and discuss tau immunotherapy in the light of these findings.
This article is part of the Special Issue entitled ‘The Synaptic Basis of Neurodegenerative Disorders’.
•Tau filaments are encountered in a group of neurodegenerative disorders termed tauopathies.•Tau is an interesting disease target in its own right.•We review recent research on tau pathology propagation and discuss tau immunotherapy.
Cerebral small-vessel disease (SVD) is characterized by periventricular white matter (WM) changes and general brain atrophy. SVD is prevalent in elderly individuals and is frequently associated with ...the development of vascular dementia (VaD). Studies of the molecular basis of SVD are sparse. We have to gain further insight into the pathogenic mechanisms of SVD. Therefore, we compared gene expression patterns in the brains of SVD and control patients, in order to identify cellular pathways changed in diseased brains. We compared the expression of mRNA transcripts in postmortem, macroscopically normal-appearing human brain tissues isolated from frontal, temporal and occipital cortical and subcortical regions in 5 SVD and 5 non-SVD control patients. Significant expression changes were determined by fold change F>1.2 in either direction, and p<0.05. We identified 228 genes differentially expressed in cortex (89 up-, 139 down-regulated) and 555 genes in WM (223 up-, 332 down-regulated) in SVD patients. Pathway analyses revealed that upregulated genes were associated with inflammation and apoptosis in WM, suggesting active cell death. Downregulated genes were associated with coagulation and fatty and amino acids metabolisms. In the cortex, down-regulated genes were principally associated with neuronal functions. Our data revealed widespread changes in the transcriptome profiles in the cortex and WM of human SVD brains, with a predominance of changes in WM. We provide for the first time a comprehensive view of the molecular alterations in human SVD brains that seem to contribute to the neuropathogenesis of SVD.
Secondary malignancies are infrequent sequelae of pituitary radiotherapy. The goal of the present case study is to analyze clinical features of a selected group of cases to define the special ...characteristics of these tumors. We report the illustrative case of a 38-year-old man with acromegaly who had transsphenoidal surgery and radiotherapy 7 years before presenting with a sellar high-grade sarcoma. Transsphenoidal and transcranial resection, as well as repeated gamma knife radiosurgery, could not prevent tumor progression and development of meningiosis sarcomatosa. We performed a thorough search of the literature and reviewed numerous publications and reports on primary and secondary sarcomas of the sella. Our search revealed 51 cases of mesenchymal malignancies after sellar radiotherapy. For further analysis, we identified and selected a group of patients based on the criteria for studying radiation-induced tumors as described by Cahan.Compared to the surgically treated group, secondary sarcomas of the sella are more frequent in patients who have had radiotherapy. These tumors occur at normal dose schedules with long latencies. Their growth is very aggressive and they may develop meningiosis sarcomatosa. Until now, no treatment modalities have been able to stop the progression of these neoplasms. Radiation-induced sarcoma is a rare sequela of pituitary radiotherapy. It is important for the treating physician to keep in mind the possibility of post-radiation sarcoma development. Additionally, one must include these tumors into the differential diagnosis in pituitary patients presenting with tumor recurrence more than 5 years after radiotherapy in combination with a secondary lack of hormonal activity.
Tau is a microtubule stabilizing protein that forms abnormal aggregates in many neurodegenerative disorders, including Alzheimer's disease. We have previously shown that co-expression of fragmented ...and full-length tau in P301SxTAU62on tau transgenic mice results in the formation of oligomeric tau species and causes severe paralysis. This paralysis is fully reversible once expression of the tau fragment is halted, even though P301S tau expression is maintained. Whereas various strategies to target tau aggregation have been developed, little is known about the long-term consequences of reverted tau toxicity. Therefore, we studied the long-term motor fitness of recovered, formerly paralysed P301SxTAU62on-off mice. To assess the seeding competence of oligomeric toxic tau species, we also inoculated ALZ17 mice with brainstem homogenates from paralysed P301SxTAU62on mice. Counter-intuitively, after recovery from paralysis due to oligomeric tau species expression, ageing P301SxTAU62on-off mice did not develop more motor impairment or tau pathology when compared to heterozygous P301S tau transgenic littermates. Thus, toxic tau species causing extensive neuronal dysfunction can be cleared without inducing seeding effects. Moreover, these toxic tau species also lack long-term tau seeding effects upon intrahippocampal inoculation into ALZ17 mice. In conclusion, tau species can be neurotoxic in the absence of seeding-competent tau aggregates, and mice can clear these tau forms permanently without tau seeding or spreading effects. These observations suggest that early targeting of non-fibrillar tau species may represent a therapeutically effective intervention in tauopathies. On the other hand, the absent seeding competence of early toxic tau species also warrants caution when using seeding-based tests for preclinical tauopathy diagnostics.
PART is part of Alzheimer disease Duyckaerts, Charles; Braak, Heiko; Brion, Jean-Pierre ...
Acta neuropathologica,
05/2015, Volume:
129, Issue:
5
Journal Article
Peer reviewed
Open access
It has been proposed that tau aggregation confined to entorhinal cortex and hippocampus, with no or only minimal Aβ deposition, should be considered as a ‘primary age-related tauopathy’ (PART) that ...is not integral to the
continuum
of sporadic Alzheimer disease (AD). Here, we examine the evidence that PART has a pathogenic mechanism and a prognosis which differ from those of AD. We contend that no specific property of the entorhinal–hippocampal tau pathology makes it possible to predict either a limited progression or the development of AD, and that biochemical differences await an evidence base. On the other hand, entorhinal–hippocampal tau pathology is an invariant feature of AD and is always associated with its development. Rather than creating a separate disease entity, we recommend the continued use of an analytical approach based on NFT stages and Aβ phases with no inference about hypothetical disease processes.
Neurodegenerative tauopathies may be inherited as autosomal-dominant disorders with variable clinicopathological phenotypes, and causative mutations in the microtubule-associated protein tau (MAPT) ...gene are not regularly seen. Herein, we describe a patient with clinically typical and autopsy-proven corticobasal degeneration (CBD). Her mother was diagnosed to have Parkinson's disease, but autopsy showed CBD pathology as in the index patient. The sister of the index patient had the clinical symptoms of primary progressive aphasia (PPA), but no pathology was available to date. Molecular analysis did not reveal any mutation in the MAPT or progranulin (GRN) genes. Our findings illustrate that CBD, progressive supranuclear palsy and PPA may be overlapping diseases with a common pathological basis rather than distinct entities. Clinical presentation and course might be determined by additional, yet unknown, genetic modifying factors.
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