Saskatchewan movement disorders program

Revealing intact neuronal circuitry in centimeter-sized formalin-fixed paraffin-embedded brain

Tissue-clearing and labeling techniques have revolutionized brain-wide imaging and analysis, yet their application to clinical formalin-fixed paraffin-embedded (FFPE) blocks remains challenging. We introduce HIF-Clear, a novel method for efficiently clearing and labeling centimeter-thick FFPE specimens using elevated temperature and concentrated detergents. HIF-Clear with multi-round immunolabeling reveals neuron circuitry regulating multiple neurotransmitter systems in a whole FFPE mouse brain and is able to be used as the evaluation of disease treatment efficiency. HIF-Clear also supports expansion microscopy and can be performed on a non-sectioned 15-year-old FFPE specimen, as well as a 3-month formalin-fixed mouse brain. Thus, HIF-Clear represents a feasible approach for researching archived FFPE specimens for future neuroscientific and 3D neuropathological analyses.

The Concept of an Epilepsy Brain Bank

Epilepsy comprises more than 40 clinical syndromes affecting millions of patients and families worldwide. To decode the molecular and pathological framework of epilepsy researchers, need reliable human epilepsy and control brain samples. Brain bank organizations collecting and supplying well-documented clinically and pathophysiologically tissue specimens are important for high-quality neurophysiology and neuropharmacology studies for epilepsy and other neurological diseases. New development in molecular mechanism and new treatment methods for neurological disorders have evoked increased demands for human brain tissue. An epilepsy brain bank is a storage source for both the frozen samples as well as the formaldehyde fixed paraffin embedded (FFPE) tissue from epilepsy surgery resections. In 2014, the University of Saskatchewan have started collecting human epilepsy brain tissues for the first time in Canada. This review highlights the necessity and importance of Epilepsy Brain bank that provides unique access for research to valuable source of brain tissue and blood samples from epilepsy patients.

Multiomics Analyses Identify Genes and Pathways Relevant to Essential Tremor

INTRODUCTION

The genetic factors and molecular mechanisms predisposing to essential tremor (ET) remains largely unknown.

OBJECTIVE

The objective of this study was to identify pathways and genes relevant to ET by integrating multiomics approaches.

METHODS

Case-control RNA sequencing of 2 cerebellar regions was done for 64 samples. A phenome-wide association study (pheWAS) of the differentially expressed genes was conducted, and a genome-wide gene association study (GWGAS) was done to identify pathways overlapping with the transcriptomic data. Finally, a transcriptome-wide association study (TWAS) was done to identify novel risk genes for ET.

RESULTS

We identified several novel dysregulated genes, including CACNA1A and SHF. Pathways including axon guidance, olfactory loss, and calcium channel activity were significantly enriched. The ET GWGAS data found calcium ion-regulated exocytosis of neurotransmitters to be significantly enriched. The TWAS also found calcium and olfactory pathways enriched. The pheWAS identified that the underexpressed differentially expressed gene, SHF, is associated with a blood pressure medication (P = 9.3E-08), which is used to reduce tremor in ET patients. Treatment of cerebellar DAOY cells with the ET drug propranolol identified increases in SHF when treated, suggesting it may rescue the underexpression.

CONCLUSION

We found that calcium-related pathways were enriched across the GWGAS, TWAS, and transcriptome. SHF was shown to have significantly decreased expression, and the pheWAS showed it was associated with blood pressure medication. The treatment of cells with propranolol showed that the drug restored levels of SHF. Overall, our findings highlight the power of integrating multiple different approaches to prioritize ET pathways and genes. © 2020 International Parkinson and Movement Disorder Society.

Parkinsonism in essential tremor cases: A clinicopathological study

BACKGROUND

Essential tremor and Parkinson's syndrome are two common movement disorders that may co-occur in some individuals. There is no diagnostic neuropathology for essential tremor, but in PD and other Parkinson's syndrome variants, the neuropathology is well known. The spectrum of Parkinson's syndrome variants associated with essential tremor, their clinical features, and course have not been determined in autopsy-confirmed cases.

OBJECTIVES

To identify: diagnostic features of essential tremor/Parkinson's syndrome, different Parkinson's syndrome variants, and long-term clinical profile in such cases.

METHODS

Patients that had an essential tremor diagnosis and a subsequent clinical or pathological diagnosis of Parkinson's syndrome seen in our clinic during 50 years were included. The diagnosis of parkinsonism was made when bradykinesia, rigidity, and resting tremor were all clinically evident.

RESULTS

Twenty-one cases were included. All the common variants of parkinsonism co-occurred with essential tremor. The most common was PD (67%) followed by PSP. The pathological findings were not predicted clinically in 2 cases that had essential tremor/PD and in all 5 essential tremor/PSP cases.

CONCLUSION

In most essential tremor/Parkinson's syndrome patients, the main motor features of parkinsonism-bradykinesia, rigidity, and resting tremor-were identifiable. All known degenerative Parkinson's syndrome variants co-occurred in essential tremor patients. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Baseline motor findings and Parkinson disease prognostic subtypes

Objective:

To identify the significance of baseline motor features to the lifelong prognostic motor subtypes in a Parkinson disease (PD) cohort.

Methods:

In a previous study of 166 PD cases, we observed different prognosis in tremor-dominant, akinetic-rigid, and mixed subtypes. This study includes the same cases, but we excluded 10 cases with symptoms of ≥15 years duration at baseline. Relative severity of tremor, bradykinesia/akinesia, and rigidity at baseline were evaluated as predictors of the motor subtypes, which are known to have different prognosis.

Results:

The most common motor subtype was mixed, followed by akinetic-rigid and then the tremor-dominant. Seventy cases were not receiving antiparkinsonian drugs at baseline. The prognostic subtypes could be predicted at baseline in 85% of all and in 91% of the treatment-naive cases. Sensitivity, specificity, and positive predictive values were strong for the mixed and the akinetic-rigid but weak for the tremor-dominant subtype.

Conclusions:

Our data show that motor profile at baseline can predict prognosis in most PD cases. These findings can be incorporated into clinical practice.

Octogenarian parkinsonism - Clinicopathological observations

BACKGROUND

Parkinson's disease is the second most common neurodegenerative disorder for which old age is the best known risk. The proportion of elderly in the world is increasing, resulting in larger pool of people at risk for Parkinson's disease. Several other neurodegenerative disorders also produce Parkinson syndrome. Distinguishing between those variants is only possible with pathological examination of brain. No autopsy confirmed study of 80 years and older onset in parkinsonism cases has been reported. Clinical features of different PS variants, response to treatment and progression of disease in this age group remain to be determined.

METHODS

Patients evaluated at Movement Disorders Clinic Saskatchewan are offered a choice of autopsy at no cost. The brain is studied by board certified neuropathologist.

RESULTS

Thirty cases with clinical diagnosis of parkinsonism (onset ≥80 years) came to autopsy. Twenty-one (70%) had Parkinson's disease alone and two (6.7%) had an additional movement disorder. The progression of Parkinson's disease was accelerated, and dementia evolved earlier than reported in the younger onset cases. Most cases that tolerated an adequate dose improved on levodopa.

CONCLUSION

Parkinson's disease is the most common variant in the octogenarian population. Most patients benefit from levodopa, and should be tried on the drug when diagnosis of parkinsonism is made.

Conjugal parkinsonism - Clinical, pathology and genetic study. No evidence of person-to-person transmission

INTRODUCTION

Neurodegeneration is known basis of several different Parkinson syndromes. The most common Parkinson syndrome is the Parkinson's disease. Distinction between different Parkinson syndromes is based on pathology or genetic findings. Recent studies indicate that several major variants of PS have some characteristics of a prion disease and may therefore be transmissible. Married couples offer a unique opportunity to study person-to-person transmission and the role of shared environments as the cause of parkinsonism.

METHODS

Autopsy is offered to patients seen at the Movement Disorders Clinic Saskatchewan at no cost. Five couples seen in our clinic, where each spouse had a clinical diagnosis of parkinsonism, came to autopsy.

RESULTS

Median duration of marriage was 42 years before the Parkinson syndrome first manifested in a spouse. Three couples were pathologically or genetically discordant for Parkinson variant. Each spouse in the other two couples had Parkinson's disease. One couple had onset separated by 20 years and one partner had a strong family history of Parkinson's disease.

CONCLUSION

Our data indicate that neither of the Parkinson's disease, Progressive Supranuclear Palsy and Multiple System Atrophy are transmitted by sexual or other intimate contact. The data also indicate against shared environments as the cause of these disorders.

Normal substantia nigra patients treated with levodopa - Clinical, therapeutic and pathological observations

BACKGROUND

Definite diagnosis of idiopathic Parkinson's disease is based on histological findings of marked substantia nigra neuronal loss and Lewy body inclusions. Almost all cases with clinical diagnosis of idiopathic Parkinson's disease are treated with levodopa. Because there is no biological marker for the diagnosis, erroneous clinical diagnosis and treatment of such cases with levodopa are well known. There is very limited literature on levodopa treated cases that had normal substantia nigra at autopsy.

METHODS

Patients seen at Movement Disorders Clinic Saskatchewan are offered autopsy at no cost to the family/estate of the patient. Autopsy studies are performed by certified neuropathologists. Notation on the status of substantia nigra is made in every autopsied case.

RESULTS

Between 1968 and 2014, 21 cases treated with levodopa had normal substantia nigra at autopsy. Eleven patients continued levodopa until death and 9 received the drug for four years or longer. No objective motor symptom benefit, dyskinesia or motor response fluctuations on levodopa were observed in any case. The most common final diagnosis was essential tremor.

CONCLUSION

Individuals with normal substantia nigra do not benefit from levodopa and do not manifest motor response fluctuations or dyskinesia. Long-term use of levodopa is not toxic to normal human substantia nigra.