WeeklySA_AdminBLOCKAGE: New research suggests that disrupted blood flow after a major clot is removed can activate a clotting protein, producing micro-clots that continue to damage brain tissue and may help explain why many patients fail to recover…
By Own Correspondent
Removing the clot that caused a stroke does not always restore healthy blood flow to the brain — and new research may help explain why some patients recover while others are left with lasting neurological damage.
A study by researchers at the University of Colorado Boulder and the University of Antwerp has shown how the brain’s own protective response can backfire after an ischaemic stroke. The process may produce tiny clots in smaller blood vessels even after the original blockage has been cleared.
Published in the journal Proceedings of the National Academy of Sciences (PNAS), the findings shed new light on a long-recognised problem known as “no reflow”: the failure of blood to circulate normally through affected brain tissue after a blocked artery has been reopened.
Ischaemic strokes occur when a clot blocks blood flow to the brain, depriving neurons of oxygen. Clot-busting medicines and endovascular thrombectomy — a procedure in which a device is threaded through a blood vessel to remove the obstruction — have transformed emergency treatment.
Yet clearing the main artery does not guarantee neurological recovery. According to the researchers, as many as half of patients do not regain meaningful neurological function despite the vessel being successfully reopened. To investigate what happens immediately after a clot is removed, the team studied mice undergoing thrombectomy and used intravital microscopy to observe blood flow and cell behaviour in the brain in real time.
Although circulation resumed quickly, it was often erratic. Blood moved in fits and starts and, in some vessels, unexpectedly reversed direction. Where these disrupted streams converged, the researchers observed tiny new clots forming in the brain’s microvasculature.
“We saw it with our own eyes. Blood that was flowing left all of a sudden flowed right and vice versa,” said senior author Frederik Denorme, an assistant professor of biology at the University of Antwerp. “It was remarkable.” Computer simulations conducted by Debanjan Mukherjee’s FLOWLab at CU Boulder helped the researchers examine the mechanics behind the phenomenon. The work implicated von Willebrand factor, a blood protein that normally helps stop bleeding.
Protein turns harmful
In its resting state, von Willebrand factor remains coiled inside blood vessels. When the body detects an injury, it stretches out, attracts platelets and helps form a clot to prevent blood loss.
After a stroke clot is removed, however, turbulent or unusual fluid motion may stretch the protein into long threads. These can attract platelets and create fresh micro-clots, blocking circulation in small vessels after the main obstruction has disappeared.At the same time, inflammation caused by the stroke appears to weaken the natural safeguards that normally restrain von Willebrand factor. The researchers describe the combination of disrupted flow, inflammation and excessive clotting as a “perfect storm” capable of causing further tissue damage.
“We now have a way to explain why so many of these patients are not seeing neurological improvements,” said Mukherjee, an assistant professor of mechanical engineering at CU Boulder. He said the findings also identify a possible new target for treatment.
Clues from patient blood
The team also examined blood samples from stroke patients and found evidence suggesting that a similar process may occur in humans. Patients with higher levels of interleukin-6, a compound associated with inflammation, had more overactive von Willebrand factor and poorer long-term outcomes.
The authors cautioned that further research is needed to determine why no reflow affects some patients but not others and to confirm how strongly the mechanism seen in laboratory models drives outcomes in people.
The findings nevertheless open a possible route to improving recovery. The researchers envisage treatments that suppress von Willebrand factor or the inflammatory signals that amplify its clotting activity being used alongside clot-busting drugs or thrombectomy.
Several medicines that act on these biological pathways are already approved for other disorders, but their safety and effectiveness in acute stroke care would have to be established in dedicated clinical trials.
“It’s early days,” Denorme said. “But now that we have a lead on what drives these micro-clots, we have a promising new avenue to explore for improving recovery.” – Newswise
HEALTH Briefs
Regular weed use tied to mental health risks
More frequent cannabis use is associated with fewer days of good mental health among adults, particularly younger men, according to new research. University of Miami Business School professor Michael T French and Kennesaw State University economist Weiwei Chen examined links between cannabis use and self-reported mental, physical and overall health.
Their study, published in Medical Care Research and Review, analysed data from adults in 38 US states who participated in the 2016–2023 Behavioural Risk Factor Surveillance System.
The researchers found that increased days of cannabis use were associated with fewer mentally healthy days among younger adults, with the relationship especially pronounced among men. Findings for people aged 65 and older were mixed and frequently not statistically significant.
The main analyses found no consistent relationship between cannabis consumption and physical health in either age group. However, the authors cautioned that the results did not mean cannabis carried no physical-health risks.
French said the expanding cannabis industry often highlighted the potential benefits of its products without fully assessing possible consequences.
He stressed that the researchers were not advocating a particular cannabis policy or law. Instead, the findings could help policymakers develop better-informed measures that consider both the potential benefits and risks associated with cannabis consumption. – Science X
Supplement boosts pancreatic cancer survival
Adding clinical-grade L-glutamine to standard chemotherapy may extend survival in patients with advanced pancreatic cancer, an early-phase trial suggests.
The Cedars-Sinai-led study, published in Nature Cancer, involved 16 patients treated with gemcitabine and nab-paclitaxel chemotherapy alongside L-glutamine supplements.
L-glutamine is an amino acid naturally produced by the body and plays an important role in digestion. Although previously investigated as a way to ease cancer-treatment side effects, this was the first human trial to evaluate it as an anticancer therapy.
Researchers reported overall survival of up to 22 months, compared with the historical eight-to-13-month range associated with standard treatment. However, the study did not directly compare patients receiving the supplement with a control group.
Half of the participants maintained their weight, an encouraging result because pancreatic cancer patients often develop cachexia, a potentially fatal loss of weight and muscle. Researchers also identified a link between patients’ gut-bacteria response to glutamine and their outcomes.
Laboratory experiments further showed that cancer cells exposed to high doses of glutamine became particularly vulnerable to chemotherapy, consistent with tumour reductions observed among patients.
The investigators said the findings were promising but must be confirmed in a larger, randomised clinical trial before the treatment can be recommended routinely. – Science X
Intermittent fasting and diabetes
Eating within a set eight-hour window each day may help adults with Type 1 diabetes and obesity manage their blood-sugar levels, according to new research from the University of Illinois Chicago (UIC).
The study, led by kinesiology and nutrition professor Krista Varady, is believed to be the first to examine the effects of intermittent fasting in people with Type 1 diabetes.
“This is the first study to examine the effects of intermittent fasting on people with Type 1 diabetes, and the results are extremely promising,” said Varady, a leading researcher on intermittent fasting.
Type 1 diabetes is a chronic condition in which the pancreas produces little or no insulin. Researchers recruited 32 adults from the Chicago area who had Type 1 diabetes and were classified as obese according to body mass index measurements.
Participants were randomly assigned to one of three groups for six months. The first followed a time-restricted eating plan, consuming food only between noon and 8pm without counting calories. The second reduced daily calorie intake by 25%, while the control group made no changes to its eating habits.
After six months, participants in the time-restricted eating group recorded better blood-sugar control than those following the calorie-reduction plan. Their HbA1c levels — which reflect average blood-sugar levels over several months — decreased by about 0.5 percentage points on average.
Crucially, time-restricted eating was not associated with an increased risk of dangerously high or low blood-sugar levels or diabetic ketoacidosis, a potentially life-threatening complication caused by insufficient insulin.
Varady nevertheless cautioned that the findings represented an initial step and should not be interpreted as a recommendation for people with diabetes to change their eating habits without medical supervision.
“Anyone making changes to their eating habits, especially those with diabetes, must work closely with their endocrinologist or healthcare provider to find a solution that works for them,” she said.
Researchers now hope to conduct larger studies across several sites to determine whether the findings can be replicated in broader populations.
The study was conducted by Varady and colleagues from UIC. – Newswise
