December 8, 2022

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High blood pressure may accelerate bone aging

High blood pressure may accelerate bone aging



 

High blood pressure may accelerate bone aging

Young mice with high blood pressure exhibit similar bone loss and osteoporosis-related bone damage as older mice , according to a recent study presented at the American Heart Association’s 2022 Hypertension Scientific Sessions .

Hypertension and osteoporosis are common conditions, and individuals may have both.

The study’s researchers investigated inflammation associated with high blood pressure in mice and found that it may be linked to osteoporosis.

 

High blood pressure may accelerate bone aging

 

 

“The bone marrow is where new bone and new immune cells are produced. We suspect that more pro-inflammatory immune cells in the bone marrow may lead to bone damage and make it weaker,” said study lead author, Vanderbilt University Biomedical Sciences Engineering doctoral candidate Elizabeth Maria Hennen said. “By understanding how high blood pressure contributes to osteoporosis, we may be able to reduce the risk of osteoporosis and better protect people from fragility fractures and reduced quality of life later in life.”

 

To investigate the potential link between high blood pressure and bone aging, the researchers compared artificially-induced young mice with older mice without high blood pressure.

According to Hennen, the older mice were 47 to 56 years old in humans, and the younger mice were between 20 and 30 years old. Twelve young (4-month-old) mice were injected with angiotensin II, a hormone that increases blood pressure.

For six weeks, young mice were given 490 ng/kg of angiotensin II. A group of 11 older mice (16 months old) were also given 490 ng/kg of angiotensin II for six weeks. Two control groups of 13 young and 9 old mice were injected with a buffer solution without angiotensin II, and these animals did not develop an increase in blood pressure.

 

After six weeks, the scientists analyzed the bones of all four groups of mice using micro-computed tomography, an advanced imaging technique.

Bone strength and density are used to determine bone health. Mathematical algorithms were used to assess the potential effects of hypertension and aging on the microstructure and strength of mouse bone.

 

The study found that young mice with induced hypertension had a significant 24% reduction in bone volume fraction and reduced thickness of the spongy bone trabeculae at the ends of long bones such as the femur and spine, compared with young mice without hypertension.

18%, and an estimated 34% reduction in failure force, which refers to the ability of a bone to withstand different types of forces.

 

“Failure translates into weaker bones,” Hennen said. “In the spine, weak bones can lead to later vertebral fractures.”

 

In contrast, aged mice that received an angiotensin-II infusion did not show similar bone loss. During the study period, however, aged mice showed similar bone loss to hypertensive young mice, regardless of whether they had hypertension.

 

“In these mice, high blood pressure at a young age basically aged the bones as if they were 15-25 years older,” Hennen said.

 

To assess the effect of inflammation on bone health in mice, the researchers analyzed bone marrow using flow cytometry.

This tool allows researchers to identify individual cells and isolate specific immune cells.

In young mice with high blood pressure, they found increased numbers of inflammatory signaling molecules, indicating increased inflammation in the bones compared to young mice that did not receive angiotensin II.

 

“This increase in active immune cells tells us that older mice are more prone to inflammation overall, and that a persistent inflammatory state may have an impact on bone health whether they have high blood pressure or not,” Hennen said.

“In young mice with high blood pressure, it appears that high blood pressure is adjusting the bone remodeling process in the direction of bone loss, rather than bone gain or bone balance.As a result, the bones become weaker, lead to an increased risk of osteoporosis and fragility fractures. In humans, this may mean that we should screen hypertensive patients for osteoporosis.”

 

The findings may help researchers identify immune cells and mechanisms that play a role in human bone health, Hennen added.

This depth of knowledge could lead to new ways to prevent osteoporosis in early adulthood.

 

Limitations of the study include that it is only descriptive, so additional research is needed to investigate how different types of immune cells specifically contribute to bone loss.

Furthermore, it is not known whether a similar link exists in humans, so similar studies in humans are needed to confirm these findings.

 

 

 

High blood pressure may accelerate bone aging

(source:internet, reference only)


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