Day: February 23, 2022

Categories : NeurologyTags :

Scientists Unravel Neurological Origins of the Placebo Effect

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Researchers at Massachusetts General Hospital (MGH) have discovered a network of brain regions activated by the placebo effect overlaps with several regions targeted by brain-stimulation therapy for depression.

The findings of this study, published in Molecular Psychiatry, will help in understanding the neurobiology of placebo effects and could inform how brain stimulation trial results are interpreted. In addition, this could provide insights on how to harness placebo effects for the treatment of a variety of conditions.

The placebo effect occurs when a patient’s symptoms improve because they expect a therapy to help (due to a variety of factors), but not from the specific effects of the treatment itself. Recent research indicates that there is a neurological basis for the placebo effect, with imaging studies identifying a pattern of changes that happen in certain brain regions when a person experiences this phenomenon.

The use of brain-stimulation techniques for patients with depression that doesn’t respond adequately to medication or psychotherapy has gained wider use in recent years. Transcranial magnetic stimulation (TMS) delivers electromagnetic pulses to the brain, and its effect on brain activity has been established over the last three decades in animal and human research studies, with several TMS devices approved by the Food and Drug Administration for treating depression. In addition, for treatment depression, deep brain stimulation (DBS, which requires an implanted device) has shown some promise.

Senior author Emiliano Santarnecchi, PhD, saw studies of brain stimulation as a unique opportunity to learn more about the neurobiology of the placebo effect. Santarnecchi and his co-investigators conducted a meta-analysis and review of neuroimaging studies involving healthy subjects and patients to create a “map” of brain regions activated by the placebo effect. They also analysed studies of people treated with TMS and DBS for depression to identify brain regions targeted by the therapies. The team found that several sites in the brain that are activated by the placebo effect overlap with brain regions targeted by TMS and DBS.

Dr Santarnecchi and his colleagues believe that this overlap has critical importance in interpreting the results of research on brain stimulation for conditions such as depression. In clinical trials, a significant portion of depression patients receiving brain stimulation improve — but so do many patients receiving placebo (sham) treatment, in which no stimulation is administered, which has led to confusion over the therapy’s benefits.

A possible explanation is “that there is a significant placebo effect when you do any form of brain stimulation intervention,” said Dr Santarnecchi. TMS involves a clinical setting, with loud clicks as the pulse is delivered. “So the patient thinks, ‘Wow, they are really activating my brain’, so you get a lot of expectation,” said Dr Santarnecchi.

Elevated placebo effects associated with brain stimulation may create problems when studying the intervention, said first author Matthew Burke, MD, a cognitive neurologist. If brain stimulation and the placebo effect overlap in activating the same brain regions, then those circuits could be maximally activated by placebo effects, which could make it difficult to show any additional benefit from TMS or DBS, said Dr Burke. If so, this could explain the disparity of results in neurostimulation treatment of depression. Screening out placebo from brain stimulation’s direct impact on brain activity will help in designing studies where the real potential of techniques such as TMS will be more easily quantified, thus improving the effect of treatment protocols.

The findings from this study also suggest broad applications for the placebo effect, said Dr Santarnecchi. “We think this is an important starting point for understanding the placebo effect in general, and learning how to modulate and harness it, including using it as a potential therapeutic tool by intentionally activating brain regions of the placebo network to elicit positive effects on symptoms,” he said.

Dr Santarnecchi and his colleagues are currently designing trials that they hope will “disentangle” the effects of brain stimulation from placebo effects and offer insights about how they can be leveraged in clinical settings.

Source: Massachusetts General Hospital

Categories : Medical Research & Technology Regenerative MedicineTags :

Sound Waves Used to Regrow Bone

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Image by Pawel Czerwinski on Unsplash

In a significant advance for the field of tissue engineering, researchers have used sound waves to turn stem cells into bone cells, a technology which may help regrow bone lost by cancer or disease.

Described in the journal Small, the innovative stem cell treatment from researchers at RMIT University offers a smart way forward for overcoming some of the field’s biggest challenges, through the precision power of high-frequency sound waves.

Tissue engineering is an emerging field that aims to rebuild bone and muscle by harnessing the human body’s natural ability to heal itself. A key challenge in regrowing bone is having sufficient amounts of bone cells that can thrive once implanted in the target area.

So far, turning stem cells into bone cells has needed complicated and expensive equipment, making widespread clinical use unrealistic.

The few clinical trials trying to regrow bone mostly used stem cells painfully extracted from a patient’s bone marrow.

In a new study published in the journal Small, the RMIT research team showed stem cells treated with high-frequency sound waves turned into bone cells quickly and efficiently.

Importantly, the treatment was effective on multiple types of cells including fat-derived stem cells, which are far less painful to extract from a patient.

Co-lead researcher Dr Amy Gelmi said the new approach was faster and simpler than other methods.

“The sound waves cut the treatment time usually required to get stem cells to begin to turn into bone cells by several days,” said Dr Gelmi. “This method also doesn’t require any special ‘bone-inducing’ drugs and it’s very easy to apply to the stem cells.

“Our study found this new approach has strong potential to be used for treating the stem cells, before we either coat them onto an implant or inject them directly into the body for tissue engineering.”

The high-frequency sound waves used in the stem cell treatment were generated on a low-cost microchip device developed by RMIT.

Co-lead researcher Distinguished Professor Leslie Yeo and his team have spent over a decade researching the interaction of sound waves at frequencies above 10MHz with different materials.

The sound wave-generating device they developed can be used to precisely manipulate cells, fluids or materials.

“We can use the sound waves to apply just the right amount of pressure in the right places to the stem cells, to trigger the change process,” Prof Yeo said.

“Our device is cheap and simple to use, so could easily be upscaled for treating large numbers of cells simultaneously – vital for effective tissue engineering.”

The next stage in the research is investigating methods to upscale the platform, working towards the development of practical bioreactors to drive efficient stem cell differentiation.

Source: RMIT

Categories : Cardiovascular Disease GenderTags :

Hypertension Risk for Women After Sexual Assault or Harassment

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Photo by Sydney Sims on Unsplash

A new study has found that women who have experienced sexual assault or harassment are at higher long-term risk of developing hypertension than women who have not.

The study appears in the Journal of the American Heart Association.

In the US, nearly 43% of women aged 20 and older have hypertension. Defined as a blood pressure of 130/80mmHg or higher, hypertension is a major risk factor for cardiovascular disease – the number one killer of women, causing one in three deaths each year.

“We know that experiences of sexual violence in the form of sexual assault and workplace sexual harassment are common, and that women are disproportionately victims of such violence, with 13–44% of women reporting sexual assault and up to 80% of women reporting workplace sexual harassment,” said study author Rebecca B. Lawn, PhD. “However, exposure to sexual violence is not widely recognized as a contributor to women’s cardiovascular health. We felt it was important to investigate the relationship among common forms of sexual violence with the risk of developing hypertension. These links could help in the early identification of factors that influence women’s long-term cardiovascular health.”

In this study, researchers analysed data over the course of seven years beginning with a 2008 follow-up of the Nurses’ Health Study II, an ongoing cohort study of US women. The 2008 follow-up measured the incidence of sexual violence and other trauma exposure, as well as post-traumatic stress disorder (PTSD) and symptoms of depression, among a subset of 54 703 of the study’s original participants.

From that subset, Lawn and colleagues analysed data for 33 127 women (95% non-Hispanic white women; average age of 53 years at the beginning of the 2008 follow-up) who had no history of hypertension or had not taken medication for high blood pressure as of the start of the 2008 follow-up.

The analyses found:

  • At the seven-year follow-up in 2015, about 1 in 5 (nearly 7100) of the women self-reported they had developed hypertension, validated with medical records.
  • Sexual assault and workplace sexual harassment were common, with lifetime prevalence of 23% for sexual assault and 12% for workplace sexual harassment; 6% of women reported experiencing both.

Compared to women with no history of sexual assault or harassment, women who reported having experienced both had the greatest increased hypertension risk (21%), followed women who reported experiencing workplace sexual harassment (15%) and an women who reported experiencing sexual assault (11%).

“We did not find any association of increased risk for hypertension among women who had a history of other types of trauma and who did not experience sexual violence, suggesting that increased hypertension risk does not appear to be associated with all trauma exposure,” Dr Lawn said. “Our finding that experiencing both sexual assault and workplace sexual harassment had the highest risk of hypertension underscores the potential compounding effects of multiple sexual violence exposures on women’s long-term cardiovascular health.”

Dr Lawn observed screening for partner violence by primary care clinicians is becoming more common, sexual violence overall is not recognised as a risk factor among women for developing cardiovascular disease.

“These results suggest that screening for a broader range of experiences of sexual violence in routine health care, including sexual harassment in the workplace, as well as verbal harassment or assault, and being aware of and treating potential cardiovascular health consequences may be beneficial for women’s long-term health,” she said. “Reducing sexual violence against women, which is important in its own right, may also provide a strategy for improving women’s lifetime cardiovascular health.”

There are several limitations to the study, including memory biases in recall of sexual violence. The sexual assault and harassment had no measures of severity or timing. Most of the women in the study were white women in the nursing field, limiting generalisability.

“We hope future studies will examine these questions with more detailed information on sexual and other forms of violence. These questions need to be investigated in more diverse groups of people of various ages, races and ethnic backgrounds and gender,” Dr Lawn said. “Although women are disproportionately victims of sexual violence, men are also victims and the physical health implications of experiences of sexual violence against men warrants further investigation.”

Source: American Heart Association

Categories : HospitalsTags :

Greenspaces in Hospitals Calm Patients and Visitors

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It can be stressful and time-consuming for patients and visitors to become accustomed to navigating large, unfamiliar hospitals, and so an architecture researcher tested a simple remedy: to let nature in with the use of indoor greenspaces and large windows.

Research conducted by West Virginia University’s associate professor Shan Jiang showed that introducing nature into large hospitals can humanise the institutional environment and reduce the stress of patients, visitors and healthcare providers.

Prof Jiang made use of immersive virtual environments for a controlled experiment that asked participants to complete various wayfinding tasks in a simulated hospital.

Though participants saw the same layout, one group encountered large windows and nature views among the corridor walls. The control group meanwhile saw solid walls without any daylight or views of nature, more like a typical modern hospital. Participants in the greenspace group used shorter time and walked less distance to complete wayfinding tasks.

“In terms of spatial orientation and wayfinding, window views of nature and small gardens can effectively break down the tedious interiors of large hospital blocks,” Prof Jiang said, “and serve as landmarks to aid people’s wayfinding and improve their spatial experience.”

In the greenspace group, participants’ mood states, particularly anger and confusion, were also found to be “significantly relieved”.

Prof Jiang’s findings are published in the Health Environments Research and Design Journal.

Based on prior research, it’s estimated that a patient or hospital visitor must go through at least seven steps in the wayfinding process to arrive at the final destination. WVU’s Center for Health Design cites wayfinding issues as an environmental stressor and a concerning topic in healthcare design.

Prof Jiang said that she was prompted to do the study by those factors, coupled with her own personal experiences (her family members have worked in healthcare) and others’ accounts of feeling lost in hospitals.

“Large hospitals can be visually welcoming but the functionality and internal circulation are indeed complex and confusing,” she said.

Greenspaces positioned at key decision points, such as main corridors or junctions, can help improve navigation.

With a background in landscape architecture, Jiang has been interested in the immediate surroundings of people in a smaller scope, particularly the indoor-outdoor relationship and the boundaries between architecture and landscapes.

Gardens and plants also tend to have strong therapeutic effects on people, she found.

“You may explain such therapeutic effects from multiple perspectives: people’s colour/hue preferences tend to range from blue to green, nature and plants are positive distractions that could restore people’s attentional fatigue, and human beings could have developed genetic preference of greenery from evolutionary perspectives,” Prof Jiang said. “All mechanisms together contribute to the positive experience when looking at gardens and nature views.”

Prof Jiang noted that many European hospitals have successfully integrated “hospital in a park” concepts. In the United States, the Lucile Packard Children’s Hospital Stanford in California has patios and window nooks in every patient room, and most rooms have direct views of a large healing garden, she said. The Alder Hey Children’s Hospital in the UK was literally built in a park.

Source: West Virginia University