Day: May 15, 2023

Categories : Diseases, Syndromes and ConditionsTags :

Solriamfetol is Best for Banishing Excessive Daytime Sleepiness

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New research in the Annals of Internal Medicine reports that the drug solriamfetol is the most effective treatment for excessive daytime sleepiness (EDS) for people with obstructive sleep apnoea (OSA).

The standard treatment for OSA is a positive airway pressure (PAP) mask that uses compressed air to support lung airways during sleep. However, some people with OSA still experience EDS and may benefit from anti-fatigue medication.

“The most important thing that people with OSA should do is use their PAP machine, but if they are still sleepy there are options in the form of medications that can reduce their tiredness,” said first author Tyler Pitre, a resident physician in internal medicine at McMaster University and incoming respirology fellow at the University of Toronto.

“Fifteen to 30 per cent of people in North America have a diagnosis of OSA and the prevalence could be much higher as many others are undiagnosed. Many people have symptoms as the condition is highly associated with obesity, which affects a large and increasing number of people in Canada, the United States and other high-income countries,” he said.

“Among those patients, many will have EDS, which affects their quality of life, making them less productive and also puts them at risk of other psychological issues. Improving this situation is of paramount importance to physicians.”

Pitre said that OSA affects nearly one billion people globally, leaving many of them at risk of EDS.

Zeraatkar and Pitre made their findings by conducting a systematic review of 14 clinical trials of anti-fatigue medications involving 3085 people, as well as analysing data from MEDLINE, CENTRAL, EMBASE and ClinicalTrials.gov in a specific network meta-analysis. They conducted their research from October 2022 to January 2023.

Senior author Zeraatkar said that while solriamfetol is likely the best medication for EDS, the drugs armodafinil-modafinil and pitolisant are also effective in combatting fatigue.

Solriamfetol can also raise blood pressure, especially risky for people with OSA, as many of them also have cardiovascular issues.

“It would be interesting to see how effective these anti-fatigue medications will be for treating related illnesses such as chronic fatigue syndrome and long COVID, now that we know they work for a similar condition,” said Zeraatkar, an assistant professor of the Department of Anesthesia.

Source: McMaster University

Categories : Cardiovascular DiseaseTags :

Unravelling the Mystery of How Statins Protect Blood Vessels

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Source: CC0

Using new genetic tools to study statins in human cells and mice, researchers have uncovered how these drugs protect the cells that line blood vessels. Published in Nature Cardiovascular Research, the findings provide new insight into statins’ curiously wide-ranging benefits, for conditions ranging from arteriosclerosis to diabetes, that have long been observed in the clinic.

“The study gives us an understanding, at a very deep mechanistic level, of why statins have such a positive effect outside of reducing LDL [low-density lipoprotein],” said professor of medicine Joseph Wu, MD, PhD, the study’s senior author. “Given how many people take statins, I think the implications are pretty profound.”

Developed in the 1980s from compounds found in mould and fungi, statins target an enzyme that regulates cholesterol production in the liver. But clinical trials have shown that they also seem to safeguard against cardiovascular disease beyond their ability to lower cholesterol.

Heart failure patients who take statins, for example, are less likely to suffer a second heart attack. They have also been shown to prevent the clogging of arteries, reduce inflammation and even lower cancer risk. Yet these underlying mechanisms are poorly understood.

“Statins were invented to lower cholesterol by targeting the liver. But we didn’t know the targets or the pathways in the cardiovascular system,” said Chun Liu, PhD, an instructor at the Stanford Cardiovascular Institute and co-lead author.

Mesenchymal cells are poor substitutes

To take a closer look at statins’ effect on blood vessels, Liu and colleagues tested a common statin, simvastatin, on lab-grown human endothelial cells derived from induced pluripotent stem cells. Endothelial cells make up the lining of blood vessels, but in many diseases they transform into a different cell type, known as mesenchymal cells, which are poor substitutes.

“Mesenchymal cells are less functional and make tissues stiffer so they cannot relax or contract correctly,” Liu said.

The researchers suspected that statins could reduce this harmful transition. Indeed, endothelial cells treated with simvastatin in a dish formed more capillary-like tubes, a sign of their enhanced ability to grow into new blood vessels.

RNA sequencing of the treated cells offered few clues. The researchers saw some changes in gene expression, but they “didn’t find anything interesting,” Liu said.

It was not until they employed a newer technique called ATAC-seq that the role of statins became apparent. ATAC-seq reveals what happens at the epigenetic level, meaning the changes to gene expression that do not involve changes to the genetic sequence.

They found that the changes in gene expression stemmed from the way strings of DNA are packaged inside the cell nucleus. DNA exists in our cells not as loose strands but as a series of tight spools around proteins, together known as chromatin. Whether particular DNA sequences are exposed or hidden in these spools determines how much they are expressed.

“When we adopted the ATAC-seq technology, we were quite surprised to find a really robust epigenetic change of the chromatin,” Liu said.

ATAC-seq revealed that simvastatin-treated cells had closed chromatin structures that reduced the expression of genes that cause the endothelial-to-mesenchymal transition. Working backward, the researchers found that simvastatin prevents a protein known as YAP from entering the nucleus and opening chromatin.

The YAP protein is known to play important roles in development, such as regulating the size of our organs, but also has been implicated in the abnormal cell growth seen in cancer.

A look at diabetes

To see the drug in context, the researchers tested simvastatin on diabetic mice. Diabetes causes subtle changes to blood vessels that mimic the damage commonly seen in people who are prescribed statins — older patients who do not have a cardiovascular condition, Liu said. 

They found that after eight weeks on simvastatin, the diabetic mice had significantly improved vascular function, with arteries that more easily relaxed and contracted.

“If we can understand the mechanism, we can fine-tune this drug to be more specific to rescuing vascular function,” Liu said.

The findings also provide a more detailed picture of the vascular disease process, which could help doctors identify and treat early signs of vascular damage.

Categories : Diseases, Syndromes and Conditions Immune SystemTags :

Autoimmune Disorders Now Affect Roughly One in Ten Individuals

On By ModernMedia
Photo by Jacek Dylag on Unsplash

A population-based study of 22 million people in the UK estimates that around one in ten individuals in the UK now live with an autoimmune disorder. The findings, published in The Lancet, also highlight important socioeconomic, seasonal and regional differences for several autoimmune disorders, providing new clues as to what factors may be involved in these conditions.

There are more than 80 known autoimmune diseases, including conditions like rheumatoid arthritis, type 1 diabetes and multiple sclerosis, some of which have been increasing in the last few decades.

This has raised the question whether overall incidence of autoimmune disorders is on the rise and what factors are involved, such as environmental factors or behavioural changes in society. The exact causes of autoimmune diseases remain largely unknown, including how much can be attributed to a genetic predisposition to disease and how much is down to exposure to environmental factors.

The study used anonymised electronic health data from 22 million individuals in the UK to investigate 19 of the most common autoimmune diseases. The authors examined whether incidence of autoimmune diseases is rising over time, who is most affected by these conditions and how different autoimmune diseases may co-exist with each other.

They found that the 19 autoimmune diseases studied affect around 10% of the population. This is higher than previous estimates, which ranged from 3–9% and often relied on smaller sample sizes and included fewer autoimmune conditions. The analysis also highlighted a higher incidence in women (13%) than men (7%).

The research discovered evidence of socioeconomic, seasonal and regional disparities for several autoimmune disorders, suggesting that these conditions are unlikely to be caused by genetic differences alone. This observation may point to the involvement of potentially modifiable risk factors such as smoking, obesity or stress. It was also found that in some cases a person with one autoimmune disease is more likely to develop a second, compared to someone without an autoimmune disease.

Dr Nathalie Conrad at the University of Oxford said: “We observed that some autoimmune diseases tended to co-occur with one another more commonly than would be expected by chance or increased surveillance alone. This could mean that some autoimmune diseases share common risk factors, such as genetic predispositions or environmental triggers. This was particularly visible among rheumatic diseases and among endocrine diseases. But this phenomenon was not generalised across all autoimmune diseases. Multiple sclerosis, for example, stood out as having low rates of co-occurrence with other autoimmune diseases, suggesting a distinct pathophysiology.”

These findings reveal novel patterns that will inform the design of further research into the possible common causes of different autoimmune diseases.

Professor Geraldine Cambridge at UCL Medicine said: “Our study highlights the considerable burden that autoimmune diseases place upon individuals and the wider population. Disentangling the commonalities and differences within this large and varied set of conditions is a complex task. There is a crucial need, therefore, to increase research efforts aimed at understanding the underlying causes of these conditions, which will support the development of targeted interventions to reduce the contribution of environmental and social risk factors.”

Source: University College London

Categories : Mental Health NeurologyTags :

Brain Transmission Speeds Increase Until Middle Age

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It has been believed speed of information transmitted among regions of the brain stabilised during early adolescence. A study in Nature Neuroscience has instead found that transmission speeds continue to increase into early adulthood, which may explain the emergence of mental health problems over this period. In fact, transmission speeds increase until around age 40, reaching a speed twice that of a 4-year old child.

As mental health problems such as anxiety, depression and bipolar disorders can emerge in late adolescence and early adulthood, a better understanding of brain development may lead to new treatments.

“A fundamental understanding of the developmental trajectory of brain circuitry may help identify sensitive periods of development when doctors could offer therapies to their patients,” says senior author Dora Hermes, PhD, a biomedical engineer at Mayo Clinic.

Called the human connectome, the structural system of neural pathways in the brain or nervous system develops as people age. But how structural changes affect the speed of neuronal signalling has not been well described.

“Just as transit time for a truck would depend on the structure of the road, so does the transmission speed of signals among brain areas depend on the structure of neural pathways,” Dr Hermes explains. “The human connectome matures during development and aging, and can be affected by disease. All these processes may affect the speed of information flow in the brain.” In the study, Dr Hermes and colleagues stimulated pairs of electrodes with a brief electrical pulse to measure the time it took signals to travel among brain regions in 74 research participants between the ages of 4 and 51. The intracranial measurements were done in a small population of patients who had electrodes implanted for epilepsy monitoring at University Medical Center Utrecht, Netherlands.

The response delays in connected brain regions showed that transmission speeds in the human brain increase throughout childhood and even into early adulthood. They plateau around 30 to 40 years of age.

The team’s data indicate that adult transmission speeds were about two times faster compared to those typically found in children. Transmission speeds also were typically faster in 30- or 40-year-old subjects compared to teenagers.

Brain transmission speed is measured in milliseconds, a unit of time equal to one-thousandth of a second. For example, the researchers measured the neuronal speed of a 4-year-old patient at 45 milliseconds for a signal to travel from the frontal to parietal regions of the brain. In a 38-year-old patient, the same pathway was measured at 20 milliseconds. For comparison, the blink of an eye takes about 100 to 400 milliseconds.

The researchers are working to characterise electrical stimulation-driven connectivity in the human brain. One of the next steps is to better understand how transmission speeds change with neurological diseases. They are collaborating with paediatric neurosurgeons and neurologists to understand how diseases change transmission speeds compared to what would be considered within the normal range for a certain age group.

Source: Mayo Clinic