Tag: atherosclerosis

Categories : Cardiovascular DiseaseTags :

Why Blood Vessel Linings go Wrong and Contribute to Plaque Growth

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University of Virginia Health researchers probing the causes of coronary artery disease have identified why blood vessel lining, which usually secure plaques to stop them drifting, sometimes instead contribute to plaque buildup. The discovery, published in Circulation: Genomic and Precision Medicine, provides new targets for scientists looking for better ways to treat and prevent the disease.

“Smooth muscle cells that make up the bulk of our blood vessels play important roles in coronary artery disease. They undergo pathological transformations as the disease develops inside our arteries,” said researcher Mete Civelek, of the University of Virginia School of Medicine’s Center for Public Health Genomics and the Department of Biomedical Engineering.

“Our results point to a previously underappreciated role for metabolic pathways during this pathological transformation,” he said.

Civelek and his team wanted to unravel a longstanding mystery about the behaviour of smooth muscle cells during plaque formation. These cells, which line blood vessels, protect the body during plaque formation by building stabilising caps over the plaque that prevent the lesions from breaking loose and causing strokes.

But sometimes smooth muscle cells begin to accelerate the plaque development and spur the progression of the disease, scientists believe.

Civelek’s new discovery helps explain why. Noah Perry, a doctoral student on Civelek’s team, analysed smooth muscle cells collected from 151 heart transplant donors and used a sophisticated approach to identify genes responsible for the smooth muscle cells’ behaviour.

After initially identifying 86 groups of genes, the researchers focused in on 18 groups that could explain the mysterious behaviour. Their analysis suggested that the smooth muscle cells’ shift might stem from problems with how the cells use nitrogen and glycogen.

The researchers identified a particular sugar, mannose, that may be contributing to the problems, potentially even triggering them. But determining that, the scientists say, will require more research.

“The metabolic shift in the cells as they transition to a disease state can point to points of intervention and therapy,” said Perry, of UVA’s Department of Biomedical Engineering, the lead author of the study.

By better understanding what triggers the smooth muscle cells to become harmful, Civelek says, doctors may be able to develop ways to prevent that from happening. That could open the door to new ways to treat and prevent coronary artery disease.

“Coronary artery disease is still the leading cause of death worldwide,” Civelek said. “Although cholesterol-lowering therapies and blood pressure control have been very effective tools to prevent deaths from heart attacks, we still need more targets to reduce the suffering of patients and their families from this devastating disease.”

Source: University of Virginia

Categories : Cardiovascular Disease GenderTags :

Atherosclerosis is a Greater Heart Attack Risk for Women

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Postmenopausal women with atherosclerosis are at higher risk of heart attacks than men of similar age, according to research presented at EACVI 2023, a scientific congress of the European Society of Cardiology (ESC), and published in European Heart Journal – Cardiovascular Imaging. Researchers used imaging techniques to examine the arteries of nearly 25 000 patients and followed them for heart attacks and death.

“The study suggests that a given burden of atherosclerosis is riskier in postmenopausal women than it is in men of that age,” said study author Dr Sophie van Rosendael of Leiden University Medical Centre. “Since atherosclerotic plaque burden is emerging as a target to decide the intensity of therapy to prevent heart attacks, the findings may impact treatment. Our results indicate that after menopause, women may need a higher dose of statins or the addition of another lipid-lowering drug. More studies are needed to confirm these findings.”

While young women do have heart attacks, in general, women develop atherosclerosis (narrowing of arteries due to plaque buildup) later in life than men and have heart attacks at an older age than men, in part because of the protective effect of oestrogen. This study examined whether the prognostic importance of atherosclerotic plaques are the same for women and men at different ages as this could be important for selecting treatments to prevent heart attacks.

The study included 24 950 patients referred for coronary computed tomography angiography (CCTA) and enrolled in the CONFIRM registry, which was conducted in six countries in North America, Europe, and Asia. CCTA is used to obtain 3D images of the arteries in the heart.

Total atherosclerotic burden was rated using the Leiden CCTA score, which incorporates the following items for each coronary segment: plaque presence (yes/no), composition (calcified, noncalcified or mixed), location, and severity of narrowing, for a final value of 0 to 42. Patients were divided into three categories previously found to predict the risk myocardial infarction: low atherosclerotic burden (0 to 5), medium (6 to 20) and high (over 20). In addition, obstructive coronary artery disease was defined as 50% narrowing or more.

The primary outcome was the difference in Leiden CCTA score between women and men of similar age. The investigators also analysed sex differences in the rates of major adverse cardiovascular events (MACE), which included all-cause death and myocardial infarction, after adjusting for age and cardiovascular risk factors (hypertension, high cholesterol, diabetes, current smoking and family history of coronary artery disease).

A total of 11 678 women (average age 58.5 years) and 13 272 men (average age 55.6 years) were followed for 3.7 years. Regarding the primary outcome, the study showed an approximately 12 year delay in the onset of coronary atherosclerosis in women: the median Leiden CCTA risk score was above zero at age 64 to 68 years in women versus 52 to 56 years in men (p<0.001). In addition, the overall plaque burden as quantified by the Leiden CCTA score was significantly lower in women, who had more non-obstructive disease.

Dr. van Rosendael said: “The results confirm the previously reported delay in the start of atherosclerosis in women. We also found that women are more likely to have non-obstructive disease. It was formerly thought that only obstructive atherosclerosis caused myocardial infarction but we now know that non-obstructive disease is also risky.”
 
The burden of atherosclerosis was equally predictive of MACE in premenopausal women (aged under 55 years) and men of the same age group. However, in postmenopausal women (age 55 years and older), the risk of MACE was higher than men for a given score. In postmenopausal women, compared to those with a low burden, those with a medium and high burden had 2.21-fold and 6.11-fold higher risks of MACE. While in men aged 55 years and older, compared to those with a low burden, those with a medium and high burden had 1.57-fold and 2.25-fold greater risks of MACE.

Dr van Rosendael said: “In this study, the elevated risk for women versus men was especially observed in postmenopausal women with the highest Leiden CCTA score. This could be partly because the inner diameter of coronary arteries is smaller in women, meaning that the same amount of plaque could have a larger impact on blood flow. Our findings link the known acceleration of atherosclerosis development after menopause with a significant increase in relative risk for women compared to men, despite a similar burden of atherosclerotic disease. This may have implications for the intensity of medical treatment.”

Source: European Society of Cardiology

Categories : Cancer Cardiovascular DiseaseTags :

Metastasis and Atherosclerosis Share an Underlying Mechanism

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Researchers have identified a key signalling molecule for cancer metastasis. one which is already known for its involvement in atherosclerosis, suggesting a possible treatment approach for both diseases simultaneously. The discovery was published in the International Journal of Cancer.

In order to become malignant, metastasising cancer, tumour cells undergo a series of transformations involving interactions with the immune system. Growing evidence exists that in tumour progression to metastasis, inflammation of blood vessel-lining endothelial cells is a key process.

A team of researchers led by Professor Kyoko Hida at Hokkaido University have discovered that, in malignant tumours, endothelial cells accumulate low-density lipoprotein (LDL) and neutrophils. Neutrophils are immune suppressor cells which are known to contribute to tumour progression.

Previous work by the team had revealed that blood vessels in malignant tumorus expressed a high level of proteoglycans, and it is known that cancerous tissue is inflamed – similar to what is seen in atherosclerosis.

The research team showed that metastasising tumors, in contrast to non-metastasising ones, accumulate proteoglycan molecules; these, in turn, attach to and accumulate LDL to the walls of blood vessels, where it becomes oxidised. There are also high levels of its receptor, LOX-1, in the blood vessel-lining endothelial cells of metastasising tumours. This, they found, causes these cells to produce inflammation signals that attract neutrophils. Using a mouse model, they proved that the suppression of LOX-1 can significantly reduce tumour malignancy, and also that LOX-1 overexpression caused an increase in signalling molecules attracting neutrophils.

This sequence of interactions observed in malignant tumours is not novel: it occurs in atherosclerosis. “Atherosclerosis and cancer appear to be completely different diseases, but they share several common pathophysiological features in the blood vessels,” said Prof Hida.

Though some questions remain, especially on the mechanism of how neutrophils contribute to cancer malignancy, this study is the first to explicitly prove the mechanistic commonalities between cardiovascular disease and cancer progression and trace the mechanism involving LDL accumulation and LOX-1 expression in in vivo tumour tissue.

“Our present study focused on the importance of LOX-1 in endothelial cells as a common factor between cancer and atherosclerosis,” Prof Hida explained. “The presence of neutrophils in tumours is a telltale sign of tumor progression.”

The study also points to a promising approach for treating and preventing malignant cancer (and cardiovascular disease) by targeting neutrophil recruitment to endothelial cells. Prof Hida concluded: “The number of patients with cancer who die not of cancer, but of cardiovascular events, is increasing. Targeting the LOX-1/oxidised LDL axis might be a promising strategy for the treatment of the two diseases concomitantly.”

Source: Hokkaido University

Categories : Cardiovascular DiseaseTags :

Long-term Use of RAS Inhibitor Drugs Could Damage Kidneys

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Photo by Robina Weermeijer on Unsplash

New research is raising concerns that long-term use of renin-angiotensin system (RAS) inhibitor drugs such as ACE inhibitors could be contributing to kidney damage.

The researchers stress that patients should continue taking the medications. But the scientists are urging studies to better understand the drugs’ long-term effects.

“Our studies show that renin-producing cells are responsible for the damage. We are now focusing on understanding how these cells, which are so important to defend us from drops in blood pressure and maintain our well-being, undergo such transformation and induce kidney damage,” said UVA’s Dr Maria Luisa Sequeira Lopez. “What is needed is to identify what substances these cells make that lead to uncontrolled vessel growth.”

A billion people around the world are affected by chronic hypertension. In a study published in JCI Insight, University of Virginia (UVA) researchers were seeking to better understand why severe forms of the condition are often accompanied by atherosclerosis in the kidney, leading to organ damage.

They found that renin cells, which help regulate blood pressure through renin production, play an important role. Harmful changes in the renin cells can cause the cells to invade the walls of the kidney’s blood vessels. The renin cells then trigger a buildup of another cell type, smooth muscle cells, that cause the vessels to thicken and stiffen, resulting in impeded kidney blood flow.

Long-term use of RAS inhibitor drugs, such as ACE inhibitors, or angiotensin receptor blockers, have a similar effect. But the study found that long-term use of the drugs was associated with hardened kidney vessels in both lab mice and humans

The researchers note that the medications can be lifesaving for patients, so they stress the importance of continuing to take them. But they say additional studies are needed to better understand the drugs’ long-term effects on the kidneys.

“It would be important to conduct prospective, randomised controlled studies to determine the extent of functional and tissue damage in patients taking medications for blood pressure control,” said UVA’s Dr Ariel Gomez. “It is imperative to find out what molecules these cells make so that we can counteract them to prevent the damage while the hypertension is treated with the current drugs available today.”

Source: University of Virginia

Categories : UncategorizedTags :

Research Suggests Vitamin C Beneficial for Severe COVID

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According to Associate Professor Anitra Carr of Otago University in New Zealand, research provides evidence that large doses of Vitamin C is beneficial for severe COVID. A 2019 study previously showed that giving Vitamin C to patients with Acute Respiratory Distress reduced mortality rates.

“A recent study that came out of the US showed that patients with coronavirus in ICU with Covid-19 also had very low vitamin C levels,” Carr said. “That’s because the body chews through a lot more of it when you get an infection – and your requirements increase significantly. But the standard doses given in the intensive care unit aren’t enough to compensate, given a severe case of the disease comes with a huge inflammatory response and oxidative stress.”

 Carr said that delivering the drug intravenously was critical to supplying the high levels of Vitamin C needed. One study from Wuhan, China showed Vitamin C conferred a survival benefit to placebo, though Carr noted that many more studies are needed and will come throughout the next year.

However, besides its normal dietary role, there was little research to show that Vitamin C had much of a preventative role. Carr said, “Some research has shown that, if you’re under enhanced stress, your risk for infection increases, so in those people vitamin C may decrease the risk of getting it. But in the general everyday population, who aren’t under extreme physical stress, it may not decrease your chances of catching the disease.”

Source: NZ Herald