Day: April 22, 2024

Inflammation may Link Depression and Cardiomyopathy

Photo by Alex Green on Pexels

Coronary artery disease and major depression may be genetically linked via inflammatory pathways to an increased risk for cardiomyopathy, a degenerative heart muscle disease, researchers at Vanderbilt University Medical Center and Massachusetts General Hospital have found.

Their report, published in Nature Mental Health, suggests that drugs prescribed for coronary artery disease and depression, when used in combination, potentially may reduce inflammation and prevent the development of cardiomyopathy.

“This work suggests that chronic low-level inflammation may be a significant contributor to both depression and cardiovascular disease,” said the paper’s corresponding author, Lea Davis, PhD, associate professor of Medicine in the Division of Genetic Medicine and Vanderbilt Genetics Institute.

The connection between depression and other serious health conditions is well known. As many as 44% of patients with coronary artery disease (CAD), the most common form of cardiovascular disease, also have a diagnosis of major depression. Yet the biological relationship between the two conditions remains poorly understood.

A possible connection is inflammation. Changes in the levels of inflammatory markers have been observed in both conditions, suggesting that there may be a common biological pathway linking neuroinflammation in depression with atherosclerotic inflammation in CAD.

In the current study, the researchers used a technique called transcriptome-wide association scans to map single nucleotide polymorphisms (genetic variations) involved in regulating the expression of genes associated with both CAD and depression.

The technique identified 185 genes that were significantly associated with both depression and CAD, and which were “enriched” for biological roles in inflammation and cardiomyopathy.

This suggests that predisposition to both depression and CAD, which the researchers called (major) depressive CAD, or (m)dCAD, may further predispose individuals to cardiomyopathy.

However, when the researchers scanned large electronic health record databases at VUMC, Mass General, and the National Institutes of Health’s All of Us Research Program, they found the actual incidence of cardiomyopathy in patients with the enriched genes for (m)dCAD was lower than in patients with CAD alone.

One possible explanation is that medications prescribed for CAD and depression, such as statins and antidepressants, may prevent development of cardiomyopathy by reducing inflammation, the researchers concluded.

“More research is needed to investigate optimal treatment mechanisms,” Davis added, “but at a minimum this work suggests that patient heart and brain health should be considered together when developing management plans to treat depression or cardiovascular disease.”

Source: Vanderbilt University Medical Center

Spotting the Aggressive Prostate Cancers among Urine Test Results

Credit: Darryl Leja National Human Genome Research Institute National Institutes Of Health

Researchers have developed a new urine-based test that addresses a major problem in prostate cancer: how to separate the slow-growing form of the disease unlikely to cause harm from more aggressive cancer that needs immediate treatment.

The test, called MyProstateScore2.0, or MPS2, looks at 18 different genes linked to high-grade prostate cancer. In multiple tests using urine and tissue samples from men with prostate cancer, it successfully identified cancers classified as Gleason 3+4=7 or Grade Group 2 (GG2), or higher. These cancers are more likely to grow and spread compared to Gleason 6 or Grade Group 1 prostate cancers, which are unlikely to spread or cause other impact. More than one-third of prostate cancer diagnoses are this low-grade form. Gleason and Grade Group are both used to classify how aggressive prostate cancer is.

Results from the University of Michigan Rogel Cancer Center-led study are published in JAMA Oncology.

“Our standard test is lacking in terms of its ability to clearly pick out those who have significant cancer. Twenty years ago, we were looking for any kind of cancer. Now we realise that slow-growing cancer doesn’t need to be treated. All of a sudden, the game changed. We went from having to find any cancer to finding only significant cancer,” said co-senior study author John T. Wei, M.D., David A. Bloom Professor of Urology at Michigan Medicine.

Prostate-specific antigen, or PSA, remains the linchpin of prostate cancer detection. MPS2 improves upon a urine-based test developed by the same U-M team nearly a decade ago, following a landmark discovery of two genes that fuse to cause prostate cancer. The original MPS test, which is used today, looked at PSA, the gene fusion TMPRSS2::ERG, and another marker called PCA3.

“There was still an unmet need with the MyProstateScore test and other commercial tests currently available. They were detecting prostate cancer, but in general they were not doing as good a job in detecting high-grade or clinically significant prostate cancer. The impetus for this new test is to address this unmet need,” said co-senior author Arul M. Chinnaiyan, M.D., Ph.D., director of the Michigan Center for Translational Pathology. Chinnaiyan’s lab discovered the T2::ERG gene fusion and developed the initial MPS test.

“If you’re negative on this test, it’s almost certain that you don’t have aggressive prostate cancer,” said Chinnaiyan, S. P. Hicks Endowed Professor of Pathology and professor of urology at Michigan Medicine.

Moreover, MPS2 was more effective at helping patients avoid unnecessary biopsies. While 11% of unnecessary biopsies were avoided with PSA testing alone, MPS2 testing would avoid up to 41% of unnecessary biopsies.

“Four of 10 men who would have a negative biopsy will have a low risk MPS2 result and can confidently skip a biopsy. If a man has had a biopsy before, the test works even better,” Wei explained.

For example, a patient may get a prostate biopsy due to an elevated PSA, but no cancer is detected. The patient is followed over time and if his PSA inches up, he would typically need another biopsy.

“In those men who have had a biopsy before and are being considered for another biopsy, MPS2 will identify half of those whose repeat biopsy would be negative. Those are practical applications for patients out there. Nobody wants to say sign me up for another biopsy. We are always looking for alternatives and this is it,” Wei said.

Source: Michigan Medicine – University of Michigan

Hot Days may Drive Inflammation and Accelerate Cardiovascular Disease

Photo by Fandy Much: https://www.pexels.com/photo/toshiba-outdoor-air-conditioner-unit-on-yellow-wall-14086132/

Short-term exposure to higher heat may increase inflammation and interfere with normal immune system functions in the body, which may, in turn, increase susceptibility to infections and accelerate the progression of cardiovascular disease, according to preliminary research be presented at the American Heart Association’s Epidemiology and Prevention – Lifestyle and Cardiometabolic Scientific Sessions 2024, March 18-21.

An inflammatory response that is longstanding (lasting weeks to months) or that occurs in healthy tissues is damaging and plays a key role in the build-up of plaque in the arteries. This may lead to atherosclerosis. Heat waves are known to promote inflammation, however, studies examining air temperature and biomarkers of inflammation have had mixed results.

“Most research only considers temperature as the exposure of interest, which may not be adequate to capture a person’s response to heat,” said lead study author Daniel W. Riggs, PhD, an assistant professor of medicine at the University of Louisville. “In our study, we used alternative measurements of heat in relation to multiple markers of inflammation and immune response in the body to investigate the short-term effects of heat exposure and produce a more complete picture of its health impact.”

Participants visited study sites in Louisville, during the summer months for a blood test, and researchers analysed the blood for multiple markers of immune system function. The researchers then examined associations between the markers of immune system function and heat levels, including temperature, net effective temperature (which factors in relative humidity, air temperature and windspeed) and the Universal Thermal Climate Index (UTCI) on that day. UTCI is a thermo-physiological model developed by the International Society of Biometeorology Commission that factors in temperature, humidity, wind speed and ultraviolet radiation levels, which was used to evaluate participant’s physical comfort.

The analysis found:

  • For every 5°F (2.8°C) increase in UTCI (in this study, the equivalent of going from a day with no thermal stress to a day with moderate thermal stress, Riggs said), there was an increase in blood levels of key inflammatory markers: monocytes (4.2%), eosinophils (9.5%), natural killer T-cells (9.9%) and tumour necrosis factor-alpha (7.0%). These immune molecules indicate activation of the body’s innate immune system, which spurs a fast and non-specific inflammatory response throughout the body to protect against pathogens and injury.
  • A decrease in B-cells (-6.8%), indicating the body’s adaptive immune system that remembers specific viruses and germs and creates antibodies to fight them, was lowered.
  • A lesser impact on the immune system was found when heat was measured by average 24-hour temperature or by net effective temperature, which incorporates humidity and wind but not sunshine.

“Our study participants only had minor exposure to high temperatures on the day of their blood test, however, even minor exposure may contribute to changes in immune markers,” Riggs said. “With rising global temperatures, the association between heat exposure and a temporarily weakened response from the immune system is a concern because temperature and humidity are known to be important environmental drivers of infectious, airborne disease transmission. Thus, during the hottest days of summer people may be at higher risk of heat exposure, they may also be more vulnerable to disease or inflammation.”

Adults over 60 years and adults with existing cardiovascular disease are particularly at risk for heat-related cardiovascular events and deaths, Riggs explained.

“It’s important for physicians to communicate with patients about the risk of adverse health effects from heat exposure. For example, cardiologists could conduct customised consultations and assessments to increase patient awareness about their susceptibility to the effects of high temperatures. Also, changes to treatment regimens may be important to consider to address other risks. For example, some medications could make people more susceptible to heat-related illness or some may not be as effective when the body is exposed to high temperatures,” Riggs said.

Source: American Heart Association

How the Brain’s Working Memory… Works

Photo by Alex Green on Unsplash

Cedars-Sinai investigators have discovered how brain cells responsible for working memory – which holds onto things like phone numbers while we use them – coordinate intentional focus and short-term storage of information. Their discovery, which confirms the involvement of the hippocampus, is published in the journal Nature.

“We have identified for the first time a group of neurons, influenced by two types of brain waves, that coordinate cognitive control and the storage of sensory information in working memory,” said Jonathan Daume, PhD, a postdoctoral scholar in the Rutishauser Lab at Cedars-Sinai and first author of the study. “These neurons don’t contain or store information, but are crucial to the storage of short-term memories.”

Working memory, which requires the brain to store information for only seconds, is fragile and requires continued focus to be maintained, explained senior study author Ueli Rutishauser, PhD, director of the Center for Neural Science and Medicine at Cedars-Sinai. It can be affected by different diseases and conditions.

“In disorders such as Alzheimer’s disease or attention-deficit hyperactivity disorder, it is often not memory storage, but rather the ability to focus on and retain a memory once it is formed that is the problem,” said Rutishauser, who is a professor of Neurosurgery, Neurology and Biomedical Sciences at Cedars-Sinai. “We believe that understanding the control aspect of working memory will be fundamental for developing new treatments for these and other neurological conditions.”

To explore how working memory functions, investigators recorded the brain activity of 36 hospitalised patients who had electrodes surgically implanted in their brains as part of an epilepsy diagnosis procedure. The team recorded the activity of individual brain cells and brain waves while the patients performed a task that required use of working memory.

On a computer screen, patients were shown either a single photo or a series of three photos of various people, animals, objects or landscapes. Next, the screen went blank for just under three seconds, requiring patients to remember the photos they just saw. They were then shown another photo and asked to decide whether it was the one (or one of the three) they had seen before.

When patients performing the working memory task were able to respond quickly and accurately, investigators noted the firing of two groups of neurons: “category” neurons that fire in response to one of the categories shown in the photos, such as animals, and “phase-amplitude coupling,” or PAC, neurons.

PAC neurons, newly identified in this study, don’t hold any content, but use a process called phase-amplitude coupling to ensure the category neurons focus and store the content they have acquired. PAC neurons fire in time with the brain’s theta waves, which are associated with focus and control, as well as to gamma waves, which are linked to information processing. This allows them to coordinate their activity with category neurons, which also fire in time to the brain’s gamma waves, enhancing patients’ ability to recall information stored in working memory.

“Imagine when the patient sees a photo of a dog, their category neurons start firing ‘dog, dog, dog’ while the PAC neurons are firing ‘focus/remember,'” Rutishauser said. “Through phase-amplitude coupling, the two groups of neurons create a harmony superimposing their messages, resulting in ‘remember dog.’ It is a situation where the whole is greater than the sum of its parts, like hearing the musicians in an orchestra play together. The conductor, much like the PAC neurons, coordinates the various players to act in harmony.”

PAC neurons do this work in the hippocampus, a part of the brain that has long been known to be important for long-term memory. This study offers the first confirmation that the hippocampus also plays a role in controlling working memory, Rutishauser said.

Source: Cedars-Sinai Medical Center

Study Explains How Aspirin can Help Prevent Colorectal Cancer Development

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Studies have shown that long-term daily use of aspirin can help to prevent the development and progression of colorectal cancer, but the mechanisms involved have been unclear. New research has revealed that aspirin may exert these protective effects by boosting certain aspects of the body’s immune response against cancer cells. The findings are published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society.

To investigate the effects of aspirin (a nonsteroidal anti-inflammatory drug) on colorectal cancer, investigators in Italy obtained tissue samples from 238 patients who underwent surgery for colorectal cancer in 2015–2019, 12% of whom were aspirin users. Patients were enrolled in the METACCRE section of the IMMUNOlogical microenvironment in the REctal Adenocarcinoma Treatment (IMMUNOREACT 8) multicenter observational study. The study was funded by the Associazione Italiana per la Ricerca sul Cancro (AIRC) and was mainly carried out at the University Hospital of Padova.

Compared with tissue samples from patients who did not use aspirin, samples from aspirin users showed less cancer spread to the lymph nodes and higher infiltration of lymphocytes into tumours. In analyses of colorectal cancer cells in the lab, exposing the cells to aspirin caused increased expression of a protein called CD80 on certain immune cells, which enhanced the capacity of the cells to alert other immune cells of the presence of tumour-associated proteins. Supporting this finding, the researchers found that in patients with rectal cancer, aspirin users had higher CD80 expression in healthy rectal tissue, suggesting a pro-immune surveillance effect of aspirin.

“Our study shows a complementary mechanism of cancer prevention or therapy with aspirin besides its classical drug mechanism involving inhibition of inflammation,” said principal investigator Marco Scarpa MD, PhD, of the University of Padova. “Aspirin is absorbed in the colon by passive diffusion to a significant degree. Its absorption is linear and depends on concentration along the bowel, and in the rectum, the concentration of orally administered aspirin can be much lower than in the rest of the colon. Thus, if we want to take advantage of its effects against colorectal cancer, we should think of how to guarantee that aspirin reaches the colorectal tract in adequate doses to be effective.” 

Source: Wiley