Are PARKIN patients ideal candidates for dopaminergic cell replacement therapies?

Parkinson's is a heterogeneous, complex condition. Stratification of Parkinson's subtypes will be essential to identify those that will benefit most from a cell replacement therapy. Foetal mesencephalic grafts can alleviate motor symptoms in some Parkinson's patients. However, on-going synucleinopathy results in the grafts eventually developing Lewy bodies, and they begin to fail. We propose that Parkinson's patients with PARKIN mutations may benefit most from a cell replacement therapy because (a) they often lack synucleinopathy, and (b) their neurodegeneration is often confined to the nigrostriatal pathway. While patients with PARKIN mutations exhibit clinical signs of Parkinson's, post-mortem studies to date indicate the majority lack Lewy bodies suggesting the nigral dopaminergic neurons are lost in a cell autonomous manner independent of α-synuclein mechanisms. Furthermore, these patients are usually younger, slow progressing and typically do not suffer from complex non-nigral symptoms that are unlikely to be ameliorated by a cell replacement therapy. Transplantation of dopaminergic cells into the putamen of these patients will provide neurons with wild-type PARKIN expression to re-innervate the striatum. The focal nature of PARKIN-mediated neurodegeneration and lack of active synucleinopathy in most young-onset cases makes these patients ideal candidates for a dopaminergic cell replacement therapy. Strategies to improve the outcome of cell replacement therapies for sporadic Parkinson's include the use of adjunct therapeutics that target α-synuclein spreading and the use of genetically engineered grafts that are resistant to synucleinopathy.

Engineering synucleinopathy-resistant human dopaminergic neurons by CRISPR-mediated deletion of the SNCA gene.

An emerging treatment for Parkinson's disease (PD) is cell replacement therapy. Authentic midbrain dopaminergic (mDA) neuronal precursors can be differentiated from human embryonic stem cells (hESCs) and human induced pluripotent stem cells (iPSCs). These laboratory-generated mDA cells have been demonstrated to mature into functional dopaminergic neurons upon transplantation into preclinical models of PD. However, clinical trials with human fetal mesenchephalic cells have shown that cell replacement grafts in PD are susceptible to Lewy body formation suggesting host-to-graft transfer of α-synuclein pathology. Here, we have used CRISPR/Cas9n technology to delete the endogenous SNCA gene, encoding for α-synuclein, in a clinical-grade hESC line to generate SNCA+/- and SNCA-/- cell lines. These hESC lines were first differentiated into mDA neurons, and then challenged with recombinant α-synuclein preformed fibrils (PFFs) to seed the formation for Lewy-like pathology as measured by phosphorylation of serine-129 of α-synuclein (pS129-αSyn). Wild-type neurons were fully susceptible to the formation of protein aggregates positive for pS129-αSyn, while SNCA+/- and SNCA-/- neurons exhibited significant resistance to the formation of this pathological mark. This work demonstrates that reducing or completely removing SNCA alleles by CRISPR/Cas9n-mediated gene editing confers a measure of resistance to Lewy pathology.

Referrals for suspected ventriculo-peritoneal shunt dysfunction and necessity for further imaging.

Shunt series (SS) X-rays are often performed as additional routine initial investigations for suspected ventriculo-peritoneal shunt dysfunction, despite low diagnostic utility and radiological implications. We reviewed such referrals at our neurosurgical unit and found an 8.3% sensitivity rate for SS; consistent with current evidence. SS should not be performed routinely.

Co-morbidities and mortality associated with intracranial bleeds and ischaemic stroke.

Stroke is a leading cause of mortality and acquired disability; however, there has been no comprehensive comparison of co-morbid risk factors between different stroke subtypes. The aim of this study was to compare risk factors and mortality for subdural haematoma (SDH), subarachnoid haemorrhage (SAH) and ischaemic and haemorrhagic stroke. We compiled a database of all patients admitted with these conditions to a large teaching hospital in Birmingham, United Kingdom during the period 2000-2007 using the International Classification of Disease (ICD) 10th revision codes. Generalised linear models were constructed to calculate relative risks (RRs) associated with co-morbidities. In total, 4804 patients were admitted with diagnoses of SDH (1004), SAH (807), ischaemic stroke (2579) and haemorrhagic stroke (414). Patients with SDH were less likely to have pneumonia (0.492, 95% CI, 0.330-0.734; p < 0.001), whereas alcohol abuse (4.21, 95% CI, 2.82-6.28; p < 0.001) was more common. In SAH, ischaemic heart disease (0.56, 95% CI, 0.40-0.79; p < 0.001) was less common. As expected, a range of cardiovascular risk factors were associated with ischaemic stroke. Epilepsy was positively associated with ischaemic stroke (1.94, 95% CI, 1.36-2.76; p < 0.001), indicating a role for targeted primary prevention in patients with epilepsy. Five-year survival was lower in ischaemic and haemorrhagic strokes (41% and 40% respectively, vs. 73% in SDH and 64% in SAH; p < 0.001). These findings may guide clinical risk stratification, and improve the prognostic information given to patients.

Dopaminergic Cell Replacement for Parkinson's Disease: Addressing the Intracranial Delivery Hurdle.

Parkinson's disease (PD) is an increasingly prevalent neurological disorder, affecting more than 8.5 million individuals worldwide. α-Synucleinopathy in PD is considered to cause dopaminergic neuronal loss in the substantia nigra, resulting in characteristic motor dysfunction that is the target for current medical and surgical therapies. Standard treatment for PD has remained unchanged for several decades and does not alter disease progression. Furthermore, symptomatic therapies for PD are limited by issues surrounding long-term efficacy and side effects. Cell replacement therapy (CRT) presents an alternative approach that has the potential to restore striatal dopaminergic input and ameliorate debilitating motor symptoms in PD. Despite promising pre-clinical data, CRT has demonstrated mixed success clinically. Recent advances in graft biology have renewed interest in the field, resulting in several worldwide ongoing clinical trials. However, factors surrounding the effective neurosurgical delivery of cell grafts have remained under-studied, despite their significant potential to influence therapeutic outcomes. Here, we focus on the key neurosurgical factors to consider for the clinical translation of CRT. We review the instruments that have been used for cell graft delivery, highlighting current features and limitations, while discussing how future devices could address these challenges. Finally, we review other novel developments that may enhance graft accessibility, delivery, and efficacy. Challenges surrounding neurosurgical delivery may critically contribute to the success of CRT, so it is crucial that we address these issues to ensure that CRT does not falter at the final hurdle.

MRI-Guided Focused Ultrasound for the Treatment of Dystonia: A Narrative Review.

Contemporary surgical management of dystonia includes neuromodulation via deep brain stimulation (DBS) or ablative techniques such as radiofrequency (RF) ablation. MRI-guided focused ultrasound (MRgFUS) is an emerging modality that uses high-intensity ultrasound to precisely ablate targets in the brain; this is incisionless, potentially avoiding the surgical risks of a burr hole and transcortical tract to reach the anatomical target. There is some evidence of efficacy in essential tremor and Parkinson's disease (PD), but, to date, there is no study aggregating the evidence of MRgFUS in dystonia. In this narrative review, we searched Medline, Embase, CINAHL, EBSCO, and ClinicalTrials.gov for primary studies and clinical trials on MRgFUS in the treatment of dystonia. Data were analyzed concerning dystonia phenotype, reported outcomes, and complications. PD-related dystonia was also included within the scope of the review. Using our search criteria, six articles on the use of MRgFUS in adult dystonia and three articles on the use of FUS in dystonia in PD were included. Four trials on the use of FUS in dystonia were also found on ClinicalTrials.gov, one of which was completed in December 2013. All included studies showed evidence of symptomatic improvement, mostly in focal hand dystonia; improvements were also found in dystonia-associated tremor, cervicobrachial dystonia, and dystonia-associated chronic neuropathic pain as well as PD-related dystonia. Reported complications included transient neurological deficits and persistent arm pain in one study. However, the evidence is limited to level-4 case series at present. MRgFUS is an emerging modality that appears to be safe and effective, particularly in focal hand dystonia, without major adverse effects. However, the quality of evidence is low at present, and long-term outcomes are unknown. High-quality prospective studies comparing MRgFUS to other surgical techniques will be useful in determining its role in the management of dystonia.

Atypical presentation of delayed communicating hydrocephalus after supratentorial glioma resection with opening of the ventricles.

We report four cases of communicating hydrocephalus, requiring shunt placement, in the subset of patients whose ventricles were breached at the time of glioma resection (a total 97 cases over 3 years). The hydrocephalus in these cases presented without ventricular dilatation on computed tomography (CT) scanning, and in 3 cases without headache. Failure to progress, visual deterioration or cerebrospinal fluid (CSF) leak in the post-operative patient after tumour resection with ventricular opening should alert clinicians to the possibility of hydrocephalus, despite the absence of headache or ventriculomegaly, and lumbar puncture should be performed without delay.

An Isogenic Collection of Pluripotent Stem Cell Lines With Elevated α-Synuclein Expression Validated for Neural Induction and Cortical Neuron Differentiation.

α-Synuclein (αSyn) is a small, disordered protein that becomes aggregated in Lewy body diseases, such as Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Human induced pluripotent stem cells (hiPSCs) potentially provide a tractable disease model to monitor early molecular changes associated with PD/DLB. We and others have previously derived hiPSC lines from patients with duplication and triplication of the SNCA gene, encoding for αSyn. It is now recognised that to perform meaningful disease modelling with these hiPSC lines, it is critical to generate isogenic control cell lines that lack the disease causing mutations. In order to complement the existing and emerging hiPSC models for PD/DLB, we have generated an allelic series of αSyn over-expressing hESC lines on the same isogenic background. An unresolved question is whether pluripotent stem cell lines, with elevated levels of αSyn, can undergo efficient differentiation into dopaminergic and cortical neurons to model PD and DLB, respectively. We took advantage of our isogenic collection of hESC lines to determine if increased expression of αSyn affects neural induction and neuronal differentiation. Clonal hESC lines with significantly different levels of αSyn expression proliferated normally and maintained expression of pluripotent markers, such as OCT4. All cell lines efficiently produced PAX6+ neuroectoderm and there was no correlation between αSyn expression and neural induction efficiency. Finally, global transcriptomic analysis of cortical differentiation of hESC lines with low or high levels of αSyn expression demonstrated robust and similar induction of cortical neuronal expression profiles. Gene expression differences observed were unrelated to neural induction and neuronal differentiation. We conclude that elevated expression of αSyn in human pluripotent stem cells does not adversely affect their neuronal differentiation potential and that collections of isogenic cell lines with differing levels of αSyn expression are valid and suitable models to investigate synucleinopathies.

Reasons for hospital admissions in dementia patients in Birmingham, UK, during 2002-2007.

BACKGROUND: There is a lack of evidence to explain why patients with dementia are admitted to a general hospital. METHODS: Main reasons for hospitalisation were investigated in all patients admitted to a multi-ethnic general hospital during 2002-2007, by analysis of type of admission and primary diagnosis on admission. Anonymised data from the Hospital Activity Analysis Register was used to trace these patients; 505 were diagnosed with Alzheimer's disease (AD), 283 with vascular dementia (VD) and 1,773 patients were classified as unspecified dementia (UnD). Logistic regression analysis was used to compare these groups to 53,123 age-matched controls. Statistical significance of p < 0.001 was accepted. RESULTS: More dementia patients were admitted as emergency cases compared to controls (AD = 95.8%, VD = 95.4%, UnD = 96.7%, controls = 54.4%; p < 0.001 for all comparisons). The proportion of patients admitted for dementia as their primary diagnosis was small (AD = 5.9%, VD = 10.6%, UnD = 6.0%). Primary diagnoses such as syncope and collapse, bronchopneumonia, urinary tract infection and dehydration were more frequent in all dementia patients than controls. CONCLUSION: Dementia patients are frequently admitted as emergency cases, but dementia itself is often not the primary diagnosis. Earlier detection of the specific conditions mentioned above may reduce emergency hospital admissions amongst dementia patients.

Epithelial-mesenchymal transition mediated tumourigenesis in the gastrointestinal tract.

Epithelial-mesenchymal transition (EMT) is a highly conserved process that has been well characterised in embryogenesis. Studies have shown that the aberrant activation of EMT in adult epithelia can promote tumour metastasis by repressing cell adhesion molecules, including epithelial (E)-cadherin. Reduced intracellular adhesion may allow tumour cells to disseminate and spread throughout the body. A number of transcription proteins of the Snail superfamily have been implicated in EMT. These proteins have been shown to be over-expressed in advanced gastrointestinal (GI) tumours including oesophageal adenocarcinomas, colorectal carcinomas, gastric and pancreatic cancers, with a concomitant reduction in the expression of E-cadherin. Regulators of EMT may provide novel clinical targets to detect GI cancers early, so that cancers previously associated with a poor prognosis such as pancreatic cancer can be diagnosed before they become inoperable. Furthermore, pharmacological therapies designed to inhibit these proteins will aim to prevent local and distant tumour invasion.

Preparation, characterization, and banking of clinical-grade cells for neural transplantation: Scale up, fingerprinting, and genomic stability of stem cell lines.

Parkinson's disease is a complex and progressive neurodegenerative condition that is characterized by the severe loss of midbrain dopaminergic (mDA) neurons, which innervate the striatum. Cell transplantation therapies to rebuild this dopaminergic network have been attempted for over 30 years. The most promising outcomes were observed when human fetal mesencephalic tissue was used as the source of cells for transplantation. However, reliance on terminations for a Parkinson's therapy presents significant logistical and ethical hurdles. An alternative source of transplantable mDA neurons is urgently needed, and the solution may come from human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs). Protocols to differentiate hESCs/iPSCs toward mDA neurons are now robust and efficient, and upon grafting the cells rescue preclinical animal models of Parkinson's disease. The challenge now is to apply Good Manufacturing Practice (GMP) to the academic discoveries and protocols to produce clinical-grade transplantable mDA cells. Major technical and logistical considerations include (i) source of hESC or iPSC line, (ii) GMP compliance of the differentiation protocol and all reagents, (iii) characterization of the cell product in terms of identity, safety, and efficacy, (iv) characterization of genomic state and stability, and (v) banking of a transplantation-ready cell product. Approaches and solutions to these challenges are reviewed here.

Cardiovascular Risk Profiles amongst Women in a Multiethnic Population in Inner City Britain: A Potential Impact of Anaemia.

The risk of diabetes is markedly reduced in men with iron deficiency anaemia (IDA). The nature of this relationship in women is not clear, nor is there information about the influence of ethnicity, given the increased susceptibility of diabetes amongst South Asians and Afro-Caribbeans. We reviewed 3563 patients with a diagnosis of anaemia from 2000 to 2007. The age-adjusted prevalence of vitamin B12 deficiency and IDA was calculated, together with cardiovascular comorbidities amongst Caucasians, South Asians, and Afro-Caribbeans. The prevalence of vitamin B12 deficiency (women only) or IDA was markedly higher in South Asians compared to Caucasians and Afro-Caribbeans. Among women with IDA, diabetes was more prevalent among South Asians (45%, 95% CI 39.0-51.0) compared to Caucasians (3.0%, 2.1-4.0); P < 0.001. Among South Asian women with vitamin B12 deficiency, the prevalence of diabetes was reduced 8.5% (5.2-12.0). South Asian women with vitamin B12 deficiency had a higher prevalence of myocardial infarction (MI) and ischemic heart disease (IHD), but this relationship was reversed in IDA. IDA is associated with a greater prevalence of diabetes in South Asian women, but it is not coordinated by a greater risk of macrovascular complications. Given the cardiovascular impact of diabetes in South Asians, this association merits further study in relation to its pathophysiological implication.

Comparison of time taken from initial presentation to histological diagnosis of Glioblastoma Multiforme (GBM) in Birmingham, United Kingdom and Strasbourg, France.

BACKGROUND: The aim of this study was to investigate possible delays in referral time for Glioblastoma multiforme (GBM) patients diagnosed at two similar neurosurgical centres (in Birmingham, UK and Strasbourg, France) and their impact on survival. Differences in the referral patterns for GBM patients within these healthcare systems may affect subsequent management and are potential targets to optimise the care of patients with GBM. METHODS: Medical case notes of 105 GBM patients in Birmingham and 81 in Strasbourg, admitted during October 2006 and April 2008, were reviewed. Data regarding demographic details, route of admission, presenting symptoms, date of initial presentation to a medical professional and dates of the first CT or MRI scan, first neurosurgical intervention, histological diagnosis and mortality was recorded. RESULTS: The median time taken from initial presentation to first neurosurgical intervention was lower in Birmingham compared to Strasbourg (13 vs. 21 days, respectively; p=0.026). Similarly, the time taken from initial presentation to histological diagnosis was lower in Birmingham (15 vs. 24 days, respectively; p=0.011). However, survival was poorer in Birmingham than Strasbourg (p=0.001) and age (HR=1.029; 95%CI 1.010-1.048; p=0.003) and time from initial presentation to neurosurgical intervention (HR=0.993; 95%CI 0.988-0.998; p=0.011) were predictors of mortality in these groups. CONCLUSION: Patients in Birmingham are diagnosed with GBM more rapidly than those in Strasbourg but they have poorer survival. Differences in disease severity may partially account for the observed results and further large scale work is required to support this study.