High blood pressure may accelerate bone aging

When high blood pressure was induced in young mice, they had bone loss and osteoporosis-related bone damage comparable to older mice, according to new research presented today at the American Heart Association’s Hypertension Scientific Sessions 2022 conference, held Sept. 7-10, 2022, in San Diego. The meeting is a scientific exchange focused on recent advances in basic and clinical research on high blood pressure and its relationship to cardiac and kidney disease, stroke, obesity and genetics.

High blood pressure and osteoporosis are prevalent diseases, and people may have both at the same time. In this study, researchers examined inflammation associated with high blood pressure in mice and found it may be connected to osteoporosis.

“Bone marrow is where both new bone and new immune cells are produced. We suspect that more pro-inflammatory immune cells in the bone marrow may be leading to damage of the bone and making it weaker,” said lead study author Elizabeth Maria Hennen, a Ph.D.-candidate in biomedical engineering at Vanderbilt University in Nashville, Tennessee. “By understanding how hypertension contributes to osteoporosis, we may be able to reduce the risk of osteoporosis and better protect people later in life from having fragility fractures and a lower quality of life.”

In the study, researchers compared young mice with induced hypertension to older mice without hypertension to assess the potential relationship of hypertension to bone aging. The human age equivalent was about 20-30 years old for the young mice and about 47-56 years old for the older mice, Hennen said. A group of 12 young mice (4 months old) were given angiotensin II, a hormone that leads to high blood pressure. The young mice received 490 nanograms/kilogram of angiotensin II for six weeks. A group of 11 older mice (16 months old) also received 490 nanograms/kilogram of angiotensin II for six weeks. Two control groups of 13 young mice and 9 old mice received a buffer solution that did not include angiotensin II, and these mice did not develop high blood pressure.

After six weeks, researchers analyzed the bones of mice from all four groups using micro-computed tomography, an advanced imaging technique. Bone health was determined by strength and density of the bone. Mathematical algorithms were used to estimate the potential effects of hypertension and aging on the microstructure and strength of the bone in the mice.

When compared to the young mice without hypertension, the young mice with induced hypertension had a significant 24% reduction in bone volume fraction, an 18% reduction in the thickness of the sponge-like trabecular bone located at the end of long bones, such as femurs and the spinal column, and a 34% reduction in estimated failure force, which is the ability of bones to withstand different types of force.

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