Smoking cannabis linked to higher stroke risk in young adults

Cannabis use may double the stroke risk in young adults, according to a recent study by researchers in the Centre for Brain Research at The University of Auckland.

The study showed that ischemic stroke and transient ischemic attack (TIA) patients were 2.3 times more likely to have cannabis detected in urine tests as other age and sex matched patients.

“This is the first case-controlled study to show a possible link to the increased risk of stroke from cannabis,” said Professor Alan Barber, lead investigator for the study and Neurological Foundation professor of clinical neurology at the University. “Cannabis has been thought by the public to be a relatively safe, although illegal substance. This study shows this might not be the case; it may lead to stroke.”

Professor Barber this week presented the study findings to the American Stroke Association’s International Stroke Conference 2013 in Honolulu. The study included 160 ischemic stroke/TIA patients aged 18-55 years who had urine screens upon admission to the hospital.

Among the patients, 150 had ischemic stroke and 10 had TIAs. Sixteen percent of patients tested positive for cannabis, and were mostly male who also smoked tobacco, while only 8.1 percent of controls tested positive for cannabis in urine samples. Researchers found no differences in age, stroke mechanism or most vascular risk factors between cannabis users and non-users.

In previous case reports, ischemic stroke and TIAs developed hours after cannabis use, says Professor Barber. “These patients usually had no other vascular risk factors apart from tobacco, alcohol and other drug usage. It’s challenging to perform prospective studies involving illegal substances such as cannabis because “questioning stroke and control patients about cannabis use is likely to obtain unreliable responses,” he says.

The study provides the strongest evidence to date of an association between cannabis and stroke, says Professor Barber. But the association is confounded because all but one of the stroke patients who were cannabis users also used tobacco regularly.

“We believe it is the cannabis use and not tobacco,” says Professor Barber, who hopes to conduct another study to determine whether there’s an association between cannabis and stroke independent of tobacco use.

“This may prove difficult given the risks of bias and ethical strictures of studying the use of an illegal substance,” he says. “However, the high prevalence of cannabis use in this cohort of younger stroke patients makes this research imperative.”

Physicians should test young people who come in with stroke for cannabis use, says Professor Barber. “People need to think twice about using cannabis, because it can affect brain development and result in emphysema, heart attack and now stroke.”

The study was funded by the Auckland District Health Board’s A+ Trust. Co-authors were: Dr Neil E. Anderson (ADHB), Dr Heidi Pridmore, Dr Venkatesh Krishnamurthy, Dr Sally Roberts, Dr David A. Spriggs, and Dr Kristie Carter.

New understanding of brain injury in preterm infants

 A study conducted by Dr Justin Dean in the Centre for Brain Research has resulted in findings with the potential to prevent or reverse serious disabilities in children born prematurely.

 The research was performed as part of Dr Dean’s postdoctoral research at the Oregon Health and Science University’s Doernbecher Children’s Hospital in the USA. Published online in the 16 January issue of Science Translational Medicine, the study is challenging the way paediatric neurologists and scientists think about brain injury in preterm infants. Specifically, it overturns the long-held belief that low blood flow to the developing brain causes death of neurons.

“The investigation has shown that brain injury in preterm born babies is not necessarily irreversible, as was previously thought”, says Dr Justin Dean from the University of Auckland’s Department of Physiology and Centre for Brain Research, who is first author for the study.

“Neuronal cells in the cortex of the brain play an important role in thinking or cognition. Loss of these cells can severely impact on normal brain function. It was very surprising to find that neurons were not actually killed in the preterm brain. Rather these cells did not develop or mature as they should, and they had less connections to other cells.”

“This finding has changed the way that we consider the cognitive and learning disabilities occur in preterm babies.”

“This opens new avenues for potential therapies to promote regeneration and repair of the premature brain.”

Lead investigator, Stephen Back, Professor of Paediatrics and neurology at OHSU, says: “As neurologists, we thought that ischemia killed the neurons and that they were irreversibly lost from the brain. But this new data challenges that notion by showing that ischemia, or low blood flow to the brain, can alter the maturation of the neurons without causing the death of these cells.

“As a result, we can focus greater attention on developing the right interventions, at the right time early in development, to promote neurons to more fully mature and reduce the often serious impact of preterm birth. This is a much more hopeful scenario.”

In studies using new MRI technology that allows injury to the developing brain to be identified much earlier than was previously feasible, the researchers looked at the cerebral cortex, or “thinking” part of the brain, which controls the complex tasks involved with learning, attention and social behaviours that are frequently impaired in children who survive preterm birth.

Specifically, they observed how brain injury in the cerebral cortex evolved over time and found no evidence that cells were dying or being lost. They did notice, however, that more brain cells were packed in to a smaller volume of brain tissue, which led, upon further examination, to the discovery that the brain cells were not fully mature.

Dr Dean says the findings are particularly exciting when looked at in association with a related study, published in the same online issue of Science Translational Medicine, in which investigators at the Hospital for Sick Children and the University of Toronto studied 95 premature infants using MRI.

“These researchers found similar MRI abnormalities in the cortex of preterm born babies to those observed in our experimental studies. Impaired growth of these babies was also the strongest predictor of these MRI abnormalities. This suggests that improving neonatal growth may allow normal development and growth of the cortex, which may reduce neurological deficits associated with preterm birth.”

“In New Zealand around 500 babies are born prematurely every year, and between 25 and 50 percent of children born prematurely develop deficits in behaviour, learning and cognition by school age,” says Dr Dean. “These two studies, taken together, provide important directions for further research into the early identification of at risk infants and potential therapies that may make a difference to neurological outcome for these children.”

Promising young brain researcher returns to NZ

Hawkes Bay-born Dr Erin Cawston has been named the 2011 Neurological Foundation Repatriation Fellow. Erin will return from her position as Research Fellow at the Mayo Clinic Arizona next month, in order to further her research into Huntington’s disease at the Centre for Brain Research.

 The Repatriation Fellowship ensures outstanding young researchers who have completed postdoctoral studies overseas can return home and continue to develop their research careers in their specialist area. Dr Cawston says “I am incredibly grateful to the Neurological Foundation for this Repatriation Fellowship allowing me to come home to New Zealand. I look forward to working with Associate Professor Michelle Glass and Professor Mike Dragunow on such an exciting project as well as being back amongst the New Zealand scientific community.” Dr Cawston begins her Fellowship at The University of Auckland in February.

 Alongside this exciting research, the Neurological Foundation has also funded a number of exciting new research projects at the CBR.

 Optimising a novel induced neural precursor-like cell line Associate Professor Bronwen Connor, Department of Pharmacology and Clinical Pharmacology, Centre for Brain Research University of Auckland, $136,862 

 The generation of ‘embryonic-like’ stem cells from adult human skin was first demonstrated in 2007. This project will advance this capability by directly generating immature brain cells (neural precursor cells) from adult human skin. Of major significance is that this will avoid the need to generate an intermediate embryonic-like stem cell phase, providing neural precursor cells for therapeutic applications without risk of tumour formation from stem cells. This project provides a unique opportunity to establish a novel technology which is likely to have wide-reaching applications for future research in the areas of neurological disease modeling, drug development, and potentially cell replacement therapy.

 A genetic mechanism underlying late-onset Alzheimer’s disease Professor Russell Snell, School of Biological Sciences University of Auckland, $86,875

 Alzheimer’s disease is a debilitating disorder affecting up to 50 per cent of those aged over 80 years old. Despite decades of research and innumerable clinical trials, there are no treatments that prevent or reverse the progression of the disease. There is currently some evidence that patients have a small proportion of brain cells with three copies of chromosome 21 instead of the normal two, leading to an increased production of the toxic protein amyloid-beta peptide. This study aims to confirm this observation, determine the pathological consequences of these cells and look for markers that make these cells different, which may lead to new therapies.

 Immodulation of stroke with risperidone Associate Professor Bronwen Connor, Department of Pharmacology and Clinical Pharmacology, Centre for Brain Research, University of Auckland, $11,999

 Stroke is a leading cause of disability in New Zealand and the burden associated with this neurological disorder is increasing. Treatment of stroke represents a large, unmet medical need. Neuroinflammation is an important pathophysiological mechanism involved in stroke and impacts profoundly on the extent of cell loss, as well as injury progression. Neuroinflammation therefore offers an exciting therapeutic target for the treatment of stroke. It has been recently demonstrated that the anti-psychotic drug, risperidone, is effective at reducing neuroinflammation and disease progression in a model of multiple sclerosis. This project will now explore whether the anti-inflammatory properties of risperidone can reduce the progression and severity of stroke. 

 Do BMP antagonists play a role in directing the fate of adult neural progenitor cells following neural cell loss?
Shwetha George, Department of Pharmacology and Clinical Pharmacology, Centre for Brain Research, University of Auckland, $4,000

 The ability for adult neural stem cells to migrate to areas of brain damage and generate replacement brain cells may provide a unique mechanism by which to develop novel therapeutic strategies for the treatment of brain injury or neurological disease. However, the local environment appears to be critical for directing the final fate of adult stem cells in the damaged brain. This study will investigate whether brain injury alters the expression of a group of compounds known as bone morphogenic protein antagonists to promote adult neural stem cells to form glial rather than neuronal cells. The results of this study will enhance our knowledge as to how stem cells respond to brain cell loss and may assist in the development of novel therapeutic strategies for the treatment of brain injury or disease.

New hope for neurological patients with Health Research Council Funding

Groundbreaking research developing new treatments for neurological disorders has been given the go-ahead with funding from the Health Research Council of New Zealand (HRC). Over $7 million of grant funding has been awarded to scientists working in the Centre for Brain Research.

The new programmes include $4.46M over five years to Professor Mike Dragunow and his team running the Biobank and Human Brain Bank. Over 100,000 New Zealanders are currently living with neurodegenerative conditions. The rate of Alzheimer’s disease is increasing in New Zealand, and CBR researchers are contributing to the global effort to find more effective treatments to combat this, and other devastating neurological disorders.

Professor Dragunow will work with Professor Richard Faull and other scientists to study the underlying causes and treatments for Alzheimer’s, epilepsy, Parkinson’s, and Huntington’s disease. The world-class team of neuroscientists and chemists has well-developed linkages with neurosurgeons, gerontologists, other clinical groups in the District Health Boards involved in clinical trials, and with NZ Biotech industries. Their goal is to translate lab-based research into therapies for patients suffering from neurodegenerative diseases.

Other projects funded include a study to determine personalized treatment pathways for stroke patients. Dr Cathy Stinear and her team at the Brain Recovery Clinic will use MRI and other techniques to define the rehabilitation strategy which will work best for each patient. In another project, Professor Laura Bennet’s team will examine whether stem cells can help brain-injured preterm babies. Meanwhile Professor Suzanne Purdy’s speech therapy team will look at therapeutic outcomes from being part of the CeleBRation Choir.

HRC New Programmes:

Professor Michael Dragunow, The University of Auckland, phone (09) 923 6403
Neurodegeneration in the Human Brain – Mechanisms and Therapeutic Targets
60 months, $4,467,504

HRC Projects:

Professor Laura Bennet, The University of Auckland, phone (09) 373 7599 ext 84890
Can Pluripotent Amnion Epithelial Cells help the Injured Preterm Brain?
36 months, $1,154,402

Professor Valery Feigin, AUT University, phone (09) 921 9166
Extension to the Traumatic Brain Injury Burden in New Zealand Study 
14 months, $345,465

Dr Cathy Stinear, The University of Auckland, phone (09) 923 3779 ext 83779
TRIO: Targeted Rehabilitation, Improved Outcomes
36 months, $1,126,268

HRC Feasibility Study Grants:

Professor Suzanne Purdy, The University of Auckland, phone (09) 373 7599 ext 82073
SPICCATO: Stroke and Parkinson’s Community Choir Engagement and Therapeutic Outcomes
12 months, $149,986

Associate Minister Health says new Brain Recovery Clinic is great for patients

You can read more about this in the New Zealand Herald or TVNZ news.

The new Brain Recovery Clinic at The University of Auckland Clinics is set to advance the treatment of brain injuries and neurological conditions, bringing together scientists and doctors.

As part of our Centre for Brain Research at Auckland University, the clinic  initially focuses on stroke and traumatic brain injury, with scientists conducting trials of new stroke rehabilitation therapies.

Associate Minister of Health Dr Jonathan Coleman opened the facility, saying the Clinic brings clinicians, researchers and the community together into one place where people can be treated and benefit from greater collaboration.

”The Centre for Brain Research is a great example of collaboration, with over 200 researchers all working towards a common goal of finding and developing new treatments for neurological disease,” Coleman said.

”The work and advances in treatment undertaken at the Clinic will lead to a better quality of life for people living with a brain injury or neurological condition. Ultimately that’s the greatest potential benefit the Clinic offers.”

New CBR research offers insight into recovery chances after stroke

Posted by Laura Fogg

Stroke patients may soon know the relief of having a definitive prediction of their chances of recovery, according to research conducted at the Centre for Brain Research.

Cathy Stinear, from the University’s Centre for Brain Research, has been investigating techniques for predicting stroke recovery. Her findings were recently published in the world’s leading neurology journal, The Lancet Neurology. Stroke is a leading cause of disability in developed countries and the ability to live independently after stroke depends largely on how well a patient can recover movement.

Dr Stinear says being able to more accurately predict a patient’s prognosis for recovery would benefit both patients and clinicians through enabling realistic goal-setting and efficient resource allocation. Current techniques for predicting recovering include motor impairment scores and neuroimaging (brain scans), while future techniques could include neurophysiological assessments – or tests to detect the extent of damage to key pathways in the brain.

“The first few days after stroke can be a very anxious time for patients. Apart from the shock, they often worry about whether they’ll be able to look after themselves and any dependents in the future. Being able to confidently and accurately predict the recovery of motor skills for these people would be a great relief,” says Dr Stinear.

Dr Stinear’s paper illustrates how investigations done within a week of stroke have very good prognostic value and new techniques including genetic testing for neural plasticity (the brain’s ability to repair itself) were showing promise. “There are many new and exciting prospects for predicting recovery after stroke. Findings so far suggest that the first tests should be those that are quick and simple, such as bedside tests of motor impairment, with progression to more complex tests if uncertainty remains. Later tests could include neurophysiological and neuroimaging assessments of motor system integrity and genetic testing,” says Dr Stinear.

Further work around stroke recovery and brain plasticity in particular is being carried out by Dr Stinear and colleagues through the Centre for Brain Research’s new Brain Recovery Clinic based at the Tamaki Campus.