Tag: 14/8/24

Categories : Paediatrics Substance UseTags : Leave a comment

Less Sleep and Later Bedtime in Childhood Linked to Future Substance Use

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Photo by cottonbro on Pexels

A good night’s sleep is essential for children’s health and development, but childhood sleep patterns may also be linked to future substance use. A new study, led by a team of Penn State researchers, found that adolescents were more likely to have consumed alcohol or tried marijuana by age 15 if they went to bed later and slept fewer hours during childhood and adolescence. The team published their findings in Annals of Epidemiology.

“The study suggests that there might be some critical ages when sleep can be a target for intervention,” said Anne-Marie Chang, associate professor of biobehavioural health at Penn State and senior author of the paper. “If we improve sleep in the school-age population, not only could that show improvements in sleep health but in other aspects like the decision to engage in risky behaviours like alcohol and other substance use.”

The research team explored childhood sleep at different developmental stages within the same sample of children to see if there’s an impact on later substance use, which few studies have investigated. They focused on two different facets of sleep health – total duration of sleep and time of sleep or bedtime. The researchers explained that if children, especially school-aged children, go to bed later, it could affect their ability to sleep well.

“Sleep is multifaceted. It’s important for children because it helps with growth and development. The brain is more plastic during younger ages and you want healthy sleep to support neural development,” said David Reichenberger, co-lead author and who earned his doctoral degree in biobehavioural health at Penn State during the time of the research. “Poor sleep health could have downstream effects on their physical health as well as decision making, which could in turn be related to their decision to engage in substance use.”

The study drew on data from 1514 children in the Future of Families and Child Wellbeing Study, a diverse longitudinal birth cohort of children from 20 cities across the United States. Parents reported their child’s regular weekday bedtime at ages three, five and nine. They also reported their child’s sleep duration at ages five and nine.

When the research team evaluated the relationship between childhood bedtime and sleep duration with future alcohol and marijuana use as teens, they found a longitudinal association. Teens were 45% more likely to try alcohol by age 15 if they had a later bedtime at age nine when compared to other children with earlier bedtimes at age nine. However, bedtime at age five wasn’t associated with future alcohol use, nor was sleep duration at ages five or nine. When it came to marijuana use, later bedtime at age five was associated with 26% increased odds of trying marijuana by age 15, while sleeping an hour less at age nine was associated with 19% increased odds of trying marijuana by age 15.

The research team also examined data from adolescents at age 15, who self-reported their bedtime, sleep duration and alcohol and marijuana use. They found that teens with a later bedtime had a 39% greater chance of drinking alcohol and a 34% greater chance of trying marijuana. Sleeping one hour less was associated with 28% increased odds of ever trying alcohol but wasn’t associated with marijuana use.

“Sleep at ages closer to adolescence is the most crucial in terms of future substance use risk. It’s that stage of development when children are rapidly changing and their brain is maturing,” Reichenberger said, noting that previous research by other groups suggests that shorter sleep duration and later bedtimes may increase impulsivity and impair decision making, which could influence substance use choices.

The findings highlight the critical role of sleep across multiple aspects of long-term health and wellbeing, researchers said. For school-age children, creating an environment that’s conducive for sleep and establishing an age-appropriate bedtime are key elements for cultivating good sleep.

“Exploring the connection between sleep and substance use is a critical area of research because we continue to struggle with an epidemic of opioid addiction and substance use,” Chang said. “It’s an important area to continue to research and to disseminate our research findings to the broader population, families and health care professionals.”

Source: University of Pennsylvania

Categories : CancerTags : Leave a comment

Faster Detection of Pancreatic Cancer

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Glycopeptide probes detect tumour-associated antibodies in blood samples

Pancreatic cancer. Credit: Scientific Animations CC BY-SA 4.0

Pancreatic cancer is one of the most lethal forms of cancer, primarily because it is usually diagnosed very late. Current markers are too insensitive and unspecific for early detection screenings. In the journal Angewandte Chemie, a research team has now introduced a new method that could lead to a significantly more precise and reliable diagnosis. It is based on the selective detection of specific antibodies in blood samples.

Tumours produce certain proteins (tumour-associated antigens) that draw the attention of our constantly “patrolling” immune system and trigger an immune response. As a consequence, antibodies directed against the tumours (tumour-associated autoantibodies) are formed, circulating in the blood at very early stages of the disease – which makes them useful for early detection. An international team led by Roberto Fiammengo and Giovanni Malerba at the University of Verona (Italy) as well as Alfredo Martínez at the Center for Biomedical Research of La Rioja (Logroño, Spain) and Francisco Corzana at the Universidad de La Rioja, has now developed an approach to diagnostic testing for pancreatic cancer that is based on the detection of such special tumour-associated autoantibodies.

They chose to use autoantibodies directed against the tumour-associated form of mucin-1 (TA-MUC1). Mucin-1 is a heavily glycosylated protein (a protein with sugar components) that occurs, for example, in glandular tissue. In many types of tumours, including pancreatic cancer, it is found in significantly elevated concentrations. In addition, the pattern of glycosylation is different from the normal form. The team’s goal was to detect autoantibodies that are directed specifically against TA-MUC1 and are a clear indicator of pancreatic cancer.

Based on structural analyses and computer simulations of known antibodies against TA-MUC1 (SM3 and 5E5), the team designed a collection of synthetic glycopeptides that mimic different segments (epitopes) of TA-MUC1. They also made unnatural modifications to increase the chances of identifying autoantibody subgroups indicative of the disease. The team immobilised these model antigens on gold nanoparticles achieving probes suitable for a serological assay (dot-blot assay). The diagnostic assay was validated with real samples from patients with pancreatic cancer and a healthy control group. Some of the nanoparticle probes could differentiate very well between samples from diseased and healthy individuals demonstrating they detected tumour associated autoantibodies. Notably, these specific autoantibodies displayed significantly better correct positive/false positive ratios than current clinical biomarkers for pancreatic cancer.

Probes with smaller glycopeptide antigens that correspond to only a single epitope, gave better results than larger probes that mimic multiple epitopes – an advantage for easier synthetic production. A short glycopeptide with an unnatural modification to its sugar component was found to be particularly effective for the detection of discriminating autoantibodies. This new structure-based approach could help in the selection of autoantibody subgroups with higher tumour specificity.

Source: Wiley

Categories : NeurologyTags : Leave a comment

Could a New Role for Propofol be Treating Epilepsy?

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Photo by Anna Shvets on Pexels

The general anaesthetic propofol may hold the keys to developing new treatment strategies for epilepsy and other neurological disorders, according to a study led by researchers at Weill Cornell Medicine and Linköping University in Sweden.

In their study, published in Nature, the researchers determined the high-resolution structural details of how propofol inhibits the activity of HCN1, an ion channel protein found on many types of neurons. Drug developers consider inhibiting HCN1 a promising strategy for treating neurologic disorders including epilepsy and chronic pain. The researchers also found, to their surprise, that when HCN1 contains either of two epilepsy-associated mutations, propofol binds to it in a way that restores its functionality.

“We might be able to exploit propofol’s unique way of binding to HCN1 for the treatment of these drug-resistant epilepsies and other HCN1-linked disorders, either by directly repurposing propofol or by designing new, more selective drugs that have the same mechanism of action,” said study co-senior author Dr Crina Nimigean, professor of physiology and biophysics in anaesthesiology at Weill Cornell Medicine.

The study’s first author was Dr Elizabeth Kim, a postdoctoral research associate in the Nimigean laboratory.  

HCN ion channels in humans come in four basic forms, HCN1 to HCN4, and are found especially on cells in the heart and nervous system. They work as switches to control the electrical voltage across the cell membrane, opening to admit an inward flow of positively charged potassium and sodium ions – thus “depolarising” the cell – when the voltage reaches a certain threshold. This function underpins much of the rhythmic activity of brain and heart muscle cells, which is why HCN channels are also called pacemaker channels.

In the study, the researchers used cryo-electron microscopy and other methods to determine, at near-atomic scale, how propofol reduces HCN1 activity – which it does with selectivity for HCN1 over other HCNs. They found that the drug inhibits HCN1 by binding within a groove between two elements of the channel protein’s central pore structure, making it harder for the pore to open.

As they investigated propofol’s action on HCN1, the researchers examined how the drug affects different known mutants of the channel, including mutants that leave it excessively open and are associated with hard-to-treat epilepsy syndromes such as early infantile epileptic encephalopathy (EIEE). The researchers were surprised to find that for two different HCN1 mutations that cause EIEE, propofol restores the mutant channels to normal or near-normal function.

From their experiments, the researchers derived a model in which the mutations decouple HCN1’s voltage-sensing and pore mechanisms, while propofol effectively recouples them, allowing membrane voltage to control ion flow again.

The results suggest at least two possibilities for translation to therapies. One is simply to use propofol, an existing, approved drug, to treat these HCN1-mutation epilepsies and potentially other HCN1-linked disorders. Propofol is a potent anesthetic that requires careful monitoring by anaesthesiologists, but it might be able to restore HCN1 function at doses below those used for general anaesthesia.

The other possibility, the researchers said, is to use the new structural data on propofol’s binding to design modified, non-anesthetic versions of propofol, or even completely different compounds, that bind to HCN1 with a similar effect but much more selectively—in other words, without binding to other channels, including other HCNs, in the body and thereby potentially causing unwanted side effects.

“For that we will need a better understanding of how propofol inhibits HCN1 better than other HCN channels,” Dr Kim said.

Source: Weill Cornell Medicine

Categories : CancerTags : Leave a comment

Unique Genetic Pattern can Predict Severe Side Effects of Melanoma Immunotherapy

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Melanoma Cells. Credit: National Cancer Institute

An activity pattern in certain genes responsible for building proteins known as spleen tyrosine kinases can predict which melanoma patients are likely to have severe side effects from immunotherapy designed to treat the most deadly skin cancer, as shown by a new study published in the journal Clinical Cancer Research.

Led by researchers at NYU Langone Health and its Perlmutter Cancer Center, the latest experiments focused on checkpoint inhibitors, drugs that have in the last decade become a mainstay of treating melanoma. This form of skin cancer kills nearly 10 000 Americans annually.

The drugs work by blocking molecules (checkpoints) that sit on the surface of immune T which the immune system uses to recognise and protect healthy cells. Cancer cells are able to hijack and turn off immune cell surveillance, evading detection. Immunotherapy drugs like nivolumab and ipilimumab are designed to block checkpoints, making cancer cells more “visible” again to T cells.

More than a third of melanoma patients given checkpoint inhibitors develop side effects so severe that they compromise their quality of life and ability to continue therapy. Side effects most often involve some form of inflammation, a sign of an overactive immune response. Patients may experience severe skin rashes, diarrhoea, or hyperthyroidism. More-severe side effects can include liver toxicity, colitis, and rheumatoid arthritis.

In the new study researchers found that even before treatment began in their test subjects, the activity of genes controlling the production of spleen tyrosine kinases predicted 83% of melanoma patients who eventually developed severe side effects from combined immunotherapy with nivolumab and ipilimumab.

Moreover, the researchers found that this heightened gene signature, as evidenced by the production of spleen tyrosine kinases, or the SYK pathway, did not interfere with the effectiveness of therapies in preventing recurrence of melanoma. The impact was connected only to side effects.

“Predictive information of this kind is critically important to oncologists and patients to help guide their immunotherapy decisions, to either minimize these side effects by taking additional precautions or to choose alternative immunotherapies,” said study co-senior investigator Tomas Kirchhoff, PhD.

“Our study results show that increased gene activity in the spleen tyrosine kinase pathway could be the basis of a possible blood test that identifies those melanoma patients most susceptible to having severe side effects from immunotherapy, and well before they start treatment,” said study co-lead investigator Kelsey Monson, PhD. 

For the study, researchers analysed immune system cell samples from 212 men and women with melanoma participating in the CheckMate-915 trial. The trial was designed to test whether combined therapy with nivolumab and ipilimumab worked better than single therapy with nivolumab in preventing postsurgical recurrence of melanoma. All immune cell samples were taken prior to the start of immunotherapy. Both drugs are manufactured by the pharmaceutical company Bristol Myers Squibb, which sponsored the CheckMate-915 trial, and provided the patient specimens and data used in the analysis.

When researchers looked at what genes were more active than others in patients who experienced side effects from their immunotherapy, they found a specific pattern among 24 genes tied to the production of spleen tyrosine kinases. Further statistical analyses showed that increased or decreased activity (transcription) of only five of these genes – CD22, PAG1, CD33, HNRNPU, and FCGR2C – along with patients’ age and the stage severity of their melanoma served as the best predictors of who would experience side effects from immunotherapy.

Study co-senior investigator Jeffrey S. Weber, MD, PhD, says that the SYK pathway has previously been linked to other autoimmune diseases, including lupus, rheumatoid arthritis, and colitis. He also points out that immunotherapy side effects were also most common in areas affected by these autoimmune diseases, including the skin, colon, and liver.

Dr Weber says the team next plans to investigate if an activated SYK pathway is predictive of side effects in patients treated with ipilimumab alone or with other combination immunotherapies.

“If our future research can explain how an activated spleen tyrosine kinase pathway leads to increased risk of side effects from immunotherapy, then it could also potentially help us to design better cancer immunotherapies and potentially other treatments for autoimmune diseases,” said Dr Kirchhoff.

Source: NYU Langone Health / NYU Grossman School of Medicine

Categories : Metabolic DisordersTags : Leave a comment

Strong Link Between Haem Iron in Red Meat and Type 2 Diabetes Risk

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Photo by Jose Ignacio Pompe on Unsplash

Higher intake of haem iron, the type found in red meat and other animal products – as opposed to non-haem iron, found mostly in plant-based foods – was associated with a higher risk of developing type 2 diabetes (T2D) in a new study published in Nature Metabolism. While the link between haem iron and T2D has been reported previously, the findings from this study, which was led by Harvard T.H. Chan School of Public Health, more clearly establish and explain the link.

“Compared to prior studies that relied solely on epidemiological data, we integrated multiple layers of information, including epidemiological data, conventional metabolic biomarkers, and cutting-edge metabolomics,” said lead author Fenglei Wang, research associate in the Department of Nutrition. “This allowed us to achieve a more comprehensive understanding of the association between iron intake and T2D risk, as well as potential metabolic pathways underlying this association.”

The researchers assessed the link between iron and T2D using 36 years of dietary reports from 206 615 adults (79% female) enrolled in the Nurses’ Health Studies I and II and the Health Professionals Follow-up Study. They examined participants’ intake of various forms of iron – total, haem, non-haem, dietary (from foods), and supplemental (from supplements) – and their T2D status, controlling for other health and lifestyle factors.

The researchers also analysed the biological mechanisms underpinning haem iron’s relationship to T2D among smaller subsets of the participants. They looked at 37 544 participants’ plasma metabolic biomarkers, including those related to insulin levels, blood sugar, blood lipids, inflammation, and two biomarkers of iron metabolism. They then looked at 9024 participants’ metabolomic profiles – plasma levels of small-molecule metabolites.

The study found a significant association between higher haem iron intake and T2D risk. Participants in the highest intake group had a 26% higher risk of developing T2D than those in the lowest intake group. In addition, the researchers found that haem iron accounted for more than half of the T2D risk associated with unprocessed red meat and a moderate proportion of the risk for several T2D-related dietary patterns. In line with previous studies, the researchers found no significant associations between intakes of non-haem iron from diet or supplements and risk of T2D.

The study also found that higher haem iron intake was associated with blood metabolic biomarkers associated with T2D. A higher haem iron intake was associated with higher levels of biomarkers such as C-peptide, triglycerides, C-reactive protein, leptin, and markers of iron overload, as well as lower levels of beneficial biomarkers like HDL cholesterol and adiponectin.

The researchers also identified a dozen blood metabolites – including L-valine, L-lysine, uric acid, and several lipid metabolites – that may play a role in the link between haem iron intake and TD2 risk. These metabolites have been previously associated with risk of T2D.

On a population level, the study findings carry important implications for dietary guidelines and public health strategies to reduce rates of diabetes, according to the researchers. In particular, the findings raise concerns about the addition of heme to plant-based meat alternatives to enhance their meaty flavor and appearance. These products are gaining in popularity, but health effects warrant further investigation.

“This study underscores the importance of healthy dietary choices in diabetes prevention,” said corresponding author Frank Hu, Fredrick J. Stare Professor of Nutrition and Epidemiology. “Reducing haem iron intake, particularly from red meat, and adopting a more plant-based diet can be effective strategies in lowering diabetes risk.”

The researchers noted that the study had several limitations, including the potential for incomplete accounting for confounders and measurement errors in the epidemiological data. In addition, the findings – based on a study population that was mostly white – need to be replicated in other racial and ethnic groups.

Source: Harvard T.H. Chan School of Public Health