Tag: ischaemic stroke

Categories : Cardiovascular Disease Lab Tests and ImagingTags :

New Blood Test for Ischaemic Stroke is a ‘Game-changer’

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Ischaemic and haemorrhagic stroke. Credit: Scientific Animations CC4.0

A new study led by investigators from Brigham and Women’s Hospital has developed a new test by combining blood-based biomarkers with a clinical score to identify patients experiencing large vessel occlusion (LVO) stroke with high accuracy. Their results are published in the journal Stroke: Vascular and Interventional Neurology.

“We have developed a game-changing, accessible tool that could help ensure that more people suffering from stroke are in the right place at the right time to receive critical, life-restoring care,” said senior author Joshua Bernstock, MD, PhD, MPH, a clinical fellow in the Department of Neurosurgery at Brigham and Women’s Hospital.

Most strokes are ischaemic, in which blood flow to the brain is obstructed. LVO strokes are an aggressive type of ischaemic stroke that occurs when an obstruction occurs in a major artery in the brain, causing brain cells to rapidly die off from lack of oxygen. Major medical emergencies, LVO strokes require the swift treatment with mechanical thrombectomy, a surgical procedure that retrieves the blockage.

“Mechanical thrombectomy has allowed people that otherwise would have died or become significantly disabled be completely restored, as if their stroke never happened,” said Bernstock. “The earlier this intervention is enacted, the better the patient’s outcome is going to be. This exciting new technology has the potential to allow more people globally to get this treatment faster.”

The research team previously targeted two specific proteins found in capillary blood, one called glial fibrillary acidic protein (GFAP), which is also associated with brain bleeds and traumatic brain injury, and one called D-dimer. In this study, they demonstrated that the levels of these blood-based biomarkers combined with field assessment stroke triage for emergency destination (FAST-ED) scores could identify LVO ischaemic strokes while ruling out other conditions such as bleeding in the brain. Brain bleeds cause similar symptoms to LVO stroke, making them hard to distinguish from one another in the field, yet treatment for each is vastly different.

In this prospective, observational diagnostic accuracy study, the researchers looked at data from a cohort of 323 patients coded for stroke in Florida between May 2021 and August 2022. They found that combining the levels of the biomarkers GFAP and D-dimer with FAST-ED data less than six hours from the onset of symptoms allowed the test to detect LVO strokes with 93% specificity and 81% sensitivity. Other findings included that the test ruled out all patients with brain bleeds, suggesting that it may also eventually be used to detect intracerebral haemorrhage in the field.

Bernstock’s team also sees promising potential future use of this accessible diagnostic tool in low- and middle-income countries, where advanced imaging is not always available. It might also be useful in assessing patients with traumatic brain injuries. Next, they are carrying out another prospective trial to measure the test’s performance when used in an ambulance. They have also designed an interventional trial that leverages the technology to expedite the triage of stroke patients by having them bypass standard imaging and move directly to intervention.

“In stroke care, time is brain,” Bernstock said. “The sooner a patient is put on the right care pathway, the better they are going to do. Whether that means ruling out bleeds or ruling in something that needs an intervention, being able to do this in a prehospital setting with the technology that we built is going to be truly transformative.

Source: Brigham and Women’s Hospital

Categories : Cardiovascular Disease NeurologyTags :

Vigorous Exercise Improves Walking in Chronic Stroke Patients

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Photo by Kampus Production on Pexels

When 67-year-old Larry Christian suffered a sudden loss of balance, he was diagnosed with a haemorrhagic stroke, and referred to the University of Delaware’s Physical Therapy Clinic for rehabilitation. 

“Initially, I had a lot of balance problems that we worked pretty intensely to correct,” Christian said. 

He enrolled in a clinical trial at UD, led by co-investigator Darcy Reisman, professor and chair of the Department of Physical Therapy, that sought to explore whether high-intensity interval training (HIIT) aids in improved gait post-stroke. UD was one of three sites selected for the clinical trial led by primary investigator and associate professor Pierce Boyne of the University of Cincinnati. Sandra Billinger, professor and vice chair of stroke translation research at the University of Kansas Medical Center, is also a co-investigator and represents the third site involved in the clinical trial. 

Now, seven years later, Christian is walking better. 

“Participating in this study got me to a point where I could walk better and even take a walk outside,” Christian said. “I’ve been pretty healthy all my life, and while I can’t play volleyball anymore, walking again made me feel great.”

Christian is among the lucky ones. Among 7 million stroke survivors in the US, fewer than 10% have adequate walking speed and endurance to complete normal daily activities like grocery shopping. 

Reisman said the results of the multi-million-dollar, five-year clinical trial showed HIIT helped more people than just Christian. The results, published in JAMA Neurology, show that chronic stroke survivors who engaged in high-intensity exercise with bursts of maximum-speed walking alternated with recovery periods saw a significant difference in their walking capacity over 12 weeks. The improvements were so dramatic Boyne and Reisman have secured a clinical trial grant renewal to triple the size of their study to 165 participants. 

She added HIIT looks different for each stroke survivor, and the optimal exercise program for each person with stroke remains unknown. 

“We want them to train at the fastest possible speed, which varies from person to person,” Reisman said. “But we don’t want them running.”

For those already walking at a reasonably fast pace, research associate Henry Wright in Reisman’s lab will add an incline or a weighted vest or wrap a bungee cord around their waist to create resistance. 

“It’s self-reported data, but participants tell me they have more energy, or they’re able to do more around the house, or they’re not winded when they go shopping,” Wright said. “By the end of the training, I can see their walking is smoother, they’re getting farther on clinical testing, and it’s rewarding to see their gains.”  

The results from the initial clinical trial showed Reisman and collaborators that HIIT was feasible and safe in a small group of stroke survivors, who saw sustained gains in walking capacity, more so than patients engaged in moderate-intensity exercise. 

However, further study of the intervention in larger populations is crucial to change the standard of care.

“Many physical therapists were trained during a time when patients with neurologic conditions, particularly stroke, were treated with kid gloves, partly because they say stroke is the heart attack of the brain,” Reisman said. “It’s common they also have cardiovascular conditions, so people tend to be extra careful with those patients in terms of pushing them.

“But what we know now is at least moderate-intensity, and likely high-intensity interval training, is essential not only for stroke survivors’ cardiovascular system but also for their brain,” Reisman said. “The evidence shows that intensity is linked to the release of neurotrophins in the brain that help the brain remodel after a stroke.” 

Kiersten McCartney, a physical therapist obtaining her doctorate in biomechanics and movement science, worked on the clinical trial with Reisman. She spent the 2022 Winter Session at Magee Rehabilitation Hospital in Philadelphia, helping them implement moderate-to-high-intensity exercise and saw the benefits first-hand. 

“I’ll never be able to say there’s no risk of heart attack. Even the fittest people can have a heart attack when exercising,” McCartney said. “Still, the data points to the idea that you’re doing more harm than good by not engaging your patients with stroke in high-intensity exercise when we talk about those longer-term outcomes.”

The HIIT-Stroke Trial 2 will continue to examine dosing to confirm whether a full 12 weeks of vigorous exercise is needed to see significant improvements in walking. Reisman and collaborators will identify whether differences in sex and other factors played a role in rehabilitation. If the five-year study results are similar and show significant gains from high-intensity interval exercise in a larger population, investigators would next work with NIH Strokenet to launch a nationwide clinical trial in people with stroke.  

“We’ve known about the value of moderate-intensity exercise for more than a decade, and it’s still not the standard of care,” Reisman said. “If we find that HIIT is the optimal intervention, the next phase would be the knowledge translation phase, where we’d systematically develop a methodology to get HIIT into clinics.” 

For HIIT to work as an intervention, Reisman said therapists will need the proper tools. She’s been pushing for commercially available heart rate monitors, placed around the chest during exercise, to be the standard of care in clinics for years.

“They’re already a standard of care for people in the community,” Reisman said. “Getting them into clinics is imperative so PTs can monitor patients’ heart rate the entire time they exercise. That constant monitoring gives therapists data on how a person is responding beyond visible signs and symptoms, and in turn, more peace of mind.” 

But beyond tools and training, Reisman said, it comes down to evidence and education. 

“If we have hundreds and hundreds of stroke survivors who’ve gone through our high-intensity exercise intervention, and we’ve seen no major adverse events – that will help,” Reisman said. “The more data we have to show therapists, the better we can implement this intervention that will change lives.”

Source: University of Delaware

Categories : Cardiovascular Disease NeurologyTags :

New Compound Restores Lost Brain Function in Mice after Stroke

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Photo by Kanashi ZD on Unsplash

An international study published recently in the journal Brain has reported promising results in restoring function lost in mice and rat models of stroke. Researchers were able to restore lost brain function using small molecules that in the future could potentially be developed into a stroke recovery therapy.

“Communication between nerve cells in large parts of the brain changes after a stroke and we show that it can be partially restored with the treatment,” says Tadeusz Wieloch, senior professor of neurobiology at Lund University in Sweden.

“Concomitantly, the rodents regain lost somatosensory functions, something that around 60 per cent of all stroke patients experience today. The most remarkable result is that the treatment began several days after a stroke,” Wieloch continues.

In an ischaemic stroke, lack of blood flow to affected parts of the brain lead to loss of function such as paralysis, sensorimotor impairment and vision and speech difficulties, but also to pain and depression.

There are currently no approved drugs that improve or restore the functions after a stroke, apart from clot-dissolving treatment in the acute phase (within 4.5 hours of the stroke). Some spontaneous improvements occur, but many stroke patients suffer chronic loss of function.

For example, about 60% of stroke sufferers, experience lost somatosensory functions such as touch and position sense.

The new study shows that rats that were treated with a class of substances that inhibit the metabotropic glutamate receptor (mGluR5), a receptor that regulates communication in the brain’s nerve cell network.

“Rodents treated with the GluR5 inhibitor regained their somatosensory functions,” says Tadeusz Wieloch, who led the study.

Two days after the stroke, ie when the damage had developed and function impairment was most prominent, the researchers started treating the rodents that exhibited the greatest impaired function.

“A temporary treatment effect was seen after just 30 minutes, but treatment for several weeks is needed to achieve a permanent recovery effect. Some function improvement was observed even when the treatment started 10 days after a stroke,” says Tadeusz Wieloch.

Importantly, sensorimotor functions improved, even though the extent of the brain damage was not diminished.

This, explains Tadeusz Wieloch, is due to the intricate network of nerve cells in the brain, known as the connectome – the way brain areas are inter connected and communicate form the basis for various brain functions.

“Impaired function after a stroke is due to cell loss, but also because of reduced activity in large parts of the connectome in the undamaged brain. The receptor mGluR5 is apparently an important factor in the reduced activity in the connectome, which is prevented by the inhibitor which therefore restores the lost brain function,” says Tadeusz Wieloch.

The results also showed that sensorimotor function was further improved if treatment with the mGluR5 inhibitor is combined with somatosensory training by housing several rodents in cages enriched with toys, chains, grids, and plastic tubes.

The researchers hope that in the future their results could lead to a clinical treatment that could be initiated a few days after an ischaemic stroke.

“Combined with rehabilitation training, it could eventually be a new promising treatment. However, more studies are needed. The study was conducted on mice and rats, and of course needs to be repeated in humans. This should be possible since several mGluR5 inhibitors have been studied in humans for the treatment of neurological diseases other than stroke, and shown to be tolerated by humans,” says Tadeusz Wieloch.

Source: Lund University

Categories : Neurodegenerative Diseases NeurologyTags :

Study Discovers a New Driver of Brain Haemorrhage Formation

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Source: CC0

A recent study has revealed a new culprit in the formation of brain haemorrhages that does not involve injury to the blood vessels, as previously believed. In the first-of-its kind study, researchers led by the University of California, Irvine discovered that interactions between aged red blood cells and brain capillaries can lead to cerebral microbleeds, offering deeper insights into how they occur and identifying potential new therapeutic targets for treatment and prevention.

The findings, published in the Journal of Neuroinflammation, describe how the team was able to watch the process by which red blood cells stall in the brain capillaries and then observe how the haemorrhage happens.

Cerebral microbleeds are associated with a variety of conditions that occur at higher rates in older adults, including hypertension, Alzheimer’s disease and ischaemic stroke.

“We have previously explored this issue in cell culture systems, but our current study is significant in expanding our understanding of the mechanism by which cerebral microbleeds develop,” said co-corresponding author Dr Mark Fisher, professor of neurology in UCI’s School of Medicine.

“Our findings may have profound clinical implications, as we identified a link between red blood cell damage and cerebral haemorrhages that occurs at the capillary level.”

The team exposed red blood cells to a chemical called tert-butyl hydroperoxide that caused oxidative stress; the cells were then marked with a fluorescent label and injected into mice.

Using two different methods, the researchers observed the red blood cells getting stuck in the brain capillaries and then being cleared out in a process called endothelial erythrophagocytosis.

As they moved out of the capillaries, microglia inflammatory cells engulfed the red blood cells, which led to the formation of a brain haemorrhage.

“It has always been assumed that in order for cerebral haemorrhage to occur, blood vessels need to be injured or disrupted. We found that increased red blood cell interactions with the brain capillaries represent an alternative source of development,” said co-corresponding author Xiangmin Xu, UCI professor of anatomy & neurobiology and director of the campus’s Center for Neural Circuit Mapping.

“We need to examine in detail the regulation of brain capillary clearance and also analyse how that process may be related to insufficient blood supply and ischaemic stroke, which is the most common form of stroke, to help advance the development of targeted treatments.”

Source: University of California – Irvine

Categories : Cardiovascular DiseaseTags :

Can Taking Statins after an Intracerebral Haemorrhage Reduce the Risk of Another Stroke?

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Source: CC0

Patients who have had an intracerebral haemorrhage who take cholesterol-lowering drugs called statins may have a lower risk of having another stroke, especially ischaemic stroke, compared to people who also had an intracerebral haemorrhage but were not taking statins, according to a new study published in Neurology, the medical journal of the American Academy of Neurology.

“Previous research has had mixed results on the risk of stroke in people who are taking statins and have already had a bleeding stroke, so we evaluated this further,” said study author David Gaist, MD, PhD, of the University of Southern Denmark in Odense and a member of the American Academy of Neurology. “We looked at whether use of statins after a bleeding stroke is associated with the risk of any additional stroke, including both those caused by bleeding and by blood clots. We found that those who used statins had a lower risk of stroke, notably ischaemic stroke, while there was no change in the risk of bleeding stroke.”

For the study, researchers looked at health records in Denmark and identified 15 151 people who had a first bleeding stroke.

People were followed from 30 days after their first bleeding stroke until the first occurrence of another stroke, death, or the end of follow-up, which on average lasted 3.3 years. Researchers used prescription data to determine information on statin use.

Researchers then compared 1959 people who had another stroke to 7400 people who did not have another stroke who were similar in age, sex and other factors. Of those who had another stroke, 757 people, or 39%, took statins compared to 3044 people, or 41%, of those who did not have a second stroke.

After adjusting for factors like hypertension, diabetes and alcohol use, statin use was associated with a 12% lower risk of another stroke.

Then they compared 1073 people who had an ischaemic stroke to 4,035 people who did not have another stroke. Of those who had an ischaemic stroke, 427 people, or 40%, took statins compared to 1687 people, or 42%, of those who did not have another stroke.

After adjusting for similar factors, statin use was associated with a 21% lower risk of an ischaemic stroke after the initial bleeding stroke.

They also compared 984 people who had another bleeding stroke to 3755 people who did not have another stroke. Of those who had a recurrent bleeding stroke, 385 people, or 39%, took statins compared to 1532 people, or 41%, of those who did not have another stroke.

After adjustments, researchers did not find a link between statin use and recurrent bleeding stroke.

“The results of our study are good news for people taking statins who have had a bleeding stroke,” Gaist added. “While we did find a lower risk of having another stroke, it is important to note that when looking at the data more closely, that lower risk was for ischaemic stroke. Still, we found no increased risk for bleeding stroke. More studies are needed to confirm our findings.”

A limitation of the study was that it only included the Danish population, which is primarily people of European ancestry, and may not be generalisable to people from other populations.

Source: American Academy of Neurology

Categories : Ageing Cardiovascular DiseaseTags :

Rethink Preventative Aspirin for Older Adults, Researchers Say

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Photo by cottonbro studio: https://www.pexels.com/photo/person-holding-white-round-medication-pill-4661296/

Low-dose aspirin is used as primary prevention for ischaemic stroke, but its protective effect weighed against the increased risk of bleeding events is controversial. A new secondary analysis of daily aspirin in older people found that, in this population, aspirin failed to reduce the risk for ischaemic stroke but increased it for intracranial bleeding. The findings were presented in JAMA Network Open.

The researchers analysed data from the ASPREE randomised clinical trial, the first large-scale trial to study the risks and benefits of 100mg daily aspirin in an older population, where increased bleeding risk may alter the balance of risks and benefits of aspirin. This is particularly relevant to intracerebral events because intracranial haemorrhage is harder to treat than ischaemic events and more frequently fatal or disabling. With previous aspirin trials in mostly younger participants, excess intracerebral haemorrhagic events was seen, though usually few in number and non-significant.

Cloud et al. performed a secondary analysis of the ASPREE trial, which included 19 114 older adults, and found a statistically significant 38% increase in intracranial bleeding resulting from a combination of haemorrhagic stroke and other causes of intracerebral haemorrhage among individuals randomised to aspirin. The difference in incidence of ischaemic stroke was not statistically significant.

While aspirin did not cause a statistically significant reduction in ischaemic stroke (hazard ratio [HR], 0.89), there was a a statistically significant 38% increase in intracranial bleeding. Rates of intracranial bleeding from those assigned to aspirin (1.1%) were higher than placebo (0.8%). This came from an increase in a combination of subdural, extradural, and subarachnoid bleeding with aspirin (0.6%) compared with placebo (0.4%). Haemorrhagic stroke was recorded in 0.5% of those assigned to aspirin compared with 0.4% for placebo.

Absolute numbers of haemorrhagic and non-haemorrhagic events were small. Among 1000 individuals taking 100mg/day of low-dose aspirin over five years, there were 2.5 fewer ischaemic strokes at the expense of 3.5 cases of intracranial haemorrhage, but not statistically significant. No difference would be expected for overall stroke incidence or stroke mortality, but haemorrhagic stroke was associated with a mortality rate of nearly a third, compared to 7.7% for ischaemic stroke. Major extracranial haemorrhage was driven by the increased risk of upper gastrointestinal bleeding with aspirin compared with placebo, as previously found (Hazard Ratio, 1.87).

The researchers concluded that “there was no statistically significant benefit from aspirin in preventing stroke or any conventional stroke etiological subtype. However, aspirin significantly increased the overall risk of intracranial bleeding.”

Categories : Cardiovascular Disease Surgeries & ProceduresTags :

Do not Automatically Bar Stroke Patients on Warfarin from EVT, Study Suggests

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Most ischaemic stroke patients taking the anticoagulant warfarin were no more likely than those not on the medication to experience a brain bleed when undergoing endovascular thrombectomy (EVT), UT Southwestern Medical Center researchers report in a new study. The findings, published in JAMA, could help doctors better gauge the risk of EVT, widening the pool of patients for this intervention.

“Although not very common, patients taking warfarin may still experience a stroke. In clinical practice, it’s very possible that some physicians may withhold an endovascular thrombectomy because patients have been treated with warfarin before their strokes. Our study could increase the number of patients for whom this lifesaving and function-saving surgery would be appropriate,” said study leader Ying Xian, MD, PhD, Associate Professor of Neurology at UT Southwestern.

EVT – a surgery that removes the clot by threading instruments through the blood vessels – is the most common treatment for acute ischaemic stroke. EVTs can sometimes cause potentially fatal symptomatic intracranial haemorrhage (sICH), Dr Xian explained. Although warfarin is a known risk factor for bleeding, it’s been unknown whether the risk of sICH following EVT is higher for stroke patients who have been on the blood thinner.

To help answer this question, Dr Xian worked with Eric Peterson, MD, MPH, Professor of Internal Medicine at UTSW, along with colleagues from other medical institutions across the country. Together, they gathered data on 32 715 stroke patients who underwent EVT within six hours of stroke symptom onset between 2015 and 2020. Data came from the American Heart Association’s Get with the Guidelines-Stroke registry – the world’s largest registry of stroke patients.

The researchers compared a variety of outcomes for the 3087 patients who took warfarin prior to stroke and the 29 628 patients who did not take any blood thinner. They evaluated whether patients experienced sICH within 36 hours of their EVT procedure, whether they had a serious systemic haemorrhage, or whether they had other complications that required additional medical intervention or an extended hospital stay. Researchers also tracked complications from additional therapies that reintroduced blood flow in the brain, in-hospital deaths, and discharges to hospice care.

After adjusting for differences inherent to patients taking or not taking warfarin, the researchers found no difference in overall risk of sICH or other adverse outcomes in patients in these two groups. However, patients with an international normalised ratio (INR) greater than 1.7 – a measure of clotting tendency of blood in patients taking warfarin – the risk of experiencing sICH increased by about 4%.

Whether this effect translates into worse outcomes for patients is unclear, Dr Peterson said. Except for higher risk of bleeding, these patients with INRs greater than 1.7 were no more likely than those not taking warfarin to die or have worse functional outcomes at discharge.

“Physicians must evaluate stroke patients on a case-by-case basis to determine whether EVT is appropriate, but our study suggests that taking warfarin alone should not necessarily be a limiting factor,” he added.

Drs Xian and Peterson said they are planning to study whether other anticoagulants frequently taken by patients at risk of stroke might increase the risk of sICH or other serious complications following EVT for ischaemic stroke.

Source: UT Southwestern Medical Center

Categories : Cardiovascular Disease GastrointestinalTags :

IBD Patients Have an Increased risk of Ischaemic Stroke

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Credit: American Heart Association

In a nationwide Swedish study of more than 85 000 patients with biopsy-confirmed inflammatory bowel disease (IBD), researchers saw an increased risk of stroke, especially ischaemic stroke, compared to the general population. The results are published in Neurology.

IBD is a chronic intestinal disease with a relapsing-remitting manner, including Crohn’s disease (CD), ulcerative colitis (UC), and IBD-unclassified. Prior studies have suggested that IBD patients have a greater risk of thromboembolic events, but evidence for long-term risk of stroke remains scarce. A recent postmarketing safety study on tofacitinib, a new drug approved for IBD treatment, found an increased stroke risk.

The researchers, from Karolinska Institutet and Örebro University (Sweden), conducted a cohort study by linking a nationwide histopathology cohort (the ESPRESSO study) to national healthcare registers in Sweden to explore whether patients with a biopsy-confirmed IBD had an increased long-term risk of stroke compared to their IBD-free siblings or the general population.

During an average follow-up of 12 years, 3720 of IBD sufferers had a stroke (32.6/10 000 person years), compared with 15 599 of the IBD-free people (27.7/10 000 person-years). When accounting for other factors, such as heart disease, hypertension and obesity, they found that people with IBD were 13% more likely to have a stroke than those without IBD. The risk stayed elevated even 25 years after IBD diagnosis, equating to one additional stroke case per 93 IBD patients. The excess risk was mainly driven by ischaemic stroke rather than haemorrhagic stroke.

The risk for ischaemic stroke was significantly increased across all IBD subtypes (ie, CD, UC, and IBD-U). Sibling comparison analyses confirmed the main findings, suggesting the excess risk of stroke may be independent of familial factors.

Clinical implications

“Due to the excess risk of stroke in IBD patients, screening and management of traditional stroke risk factors in IBD patients could be more urgent to prevent fatal CVD complications”, says first author Jiangwei Sun, postdoc at the Department of Medical Epidemiology and Biostatistics.

“These findings highlight the need for clinical vigilance about the long-term excess risk of cerebrovascular events in IBD patients”, adds last author Jonas F Ludvigsson, professor at Karolinska Institutet and pediatrician at Örebro University Hospital.

Source: Karolinska Institutet

Categories : Cardiovascular Disease Exercise GenderTags :

Strenuous Jobs Increase Men’s Cardiovascular Risk, but Reduce Women’s

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Photo by K. Mitch Hodge on Unsplash

A long-term Danish study found that high physical activity at work was associated with higher risk of ischaemic heart disease (IHD) in men, but in women, this was associated with lower risk. The findings, published in the European Journal of Preventive Cardiology, highlight the importance of taking gender into account when considering the impact of high levels of occupational physical activity (OPA).

While previous studies have shown that physical activities in leisure time are protective against cardiovascular disease, high levels of OPA were shown to have no benefit – or even a detrimental effect.

The study followed up participants aged 30–61 years old after 34 years who took part in the Danish Monica 1 study in 1982–84. Participants, 1399 women and 1706 men, were actively employed, without prior IHD and who answered a question on OPA. The participants’ medical records were located in the Danish National Patient Registry and the researchers analysed the data, controlling for increasing numbers of factors such as age, then age and sex, and then age and sex plus factors such as smoking.

Compared to women doing sedentary work, women in all other OPA categories had a lower hazard ratio (HR) for IHD. Among men, the risk of IHD was 22% higher among those with light OPA, and 42% and 46% higher among those with moderate OPA with some lifting or strenuous work with heavy lifting, respectively, compared to men with sedentary OPA. Compared to women with sedentary work, HR for IHD was higher among men in all OPA categories, and a statistically significant interaction between OPA and sex was found.

Demanding or strenuous OPA seems to be a risk factor for IHD among men, whereas a higher level of OPA seems to protect from IHD among women. The researchers wrote that this underlines the importance of taking into account sex differences in studies of health effects of OPA. Future studies should investigate the underlying mechanisms for this difference, such as differences in exposure and physiology.

Categories : Cardiovascular Disease Lab Tests and ImagingTags :

Sex Differences in Brain Glycogen After a Stroke may Yield New Treatments

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Credit: American Heart Association

Although males and females are equally impacted by stroke, there are differences in recovery. Since oestrogen and progesterone have known neuroprotective effects, it is important to gauge their effects in stroke recovert. In a paper published in IBRO Neuroscience Reports, researchers have discovered differences between biomarkers such as glycogen levels in the brains of male and female mice.

“A stroke is caused by a loss of blood flow to brain cells. Without urgent intervention this may cause those cells to die because they constantly need energy and nutrients from the blood,” said Prof Nicole Sylvain, clinical research coordinator and lab manager at the University of Saskatchewan.

Sylvain and her colleagues are looking at treatments for post-stroke recovery that help supplement these energy losses. Using the Canadian Light Source (CLS) at the University of Saskatchewan (USask), the team was able to identify energy biomarkers in the brain, which could eventually inform clinicians about the effects of potential stroke treatments on brain recovery after a stroke.

The group’s recent study examined post-stroke differences between male and female mice, and found that female mice have higher amounts of glycogen in their brains. When the supply of glycogen is disrupted by stroke, the brain is severely impacted.

Most pre-clinical stroke research has been performed using male lab animals, with results usually generalised to both sexes. In clinical stoke cases, females have a higher incidence of ischaemic stroke and poorer outcomes, compared to males.

“We found that, for the most part, male data can be generalised for females, however, some of the metabolic markers we measured were actually different,” Sylvain said. “It’s really important to do the research on both sexes.”

It would be impossible for the team to detect the biomarkers without to the Mid-IR beamline.

“The only way to detect them in such an accurate way across the brain is with infrared imaging, so the CLS has been absolutely vital to our research.”

Source: University of Saskatchewan