High blood pressure linked to bone loss and aging, mouse study finds

  • Evidence suggests that high blood pressure or high blood pressure is linked to an increased risk of bone loss.
  • A recent study in a mouse model shows that high blood pressure can accelerate bone loss in young animals similar to that seen during the typical aging process.
  • Bone loss observed in young animals with high blood pressure was associated with increased inflammation.
  • Understanding the mechanisms responsible for the decline in bone health induced by high blood pressure could help develop therapies to prevent bone loss in young adults.

A recent study suggests that high blood pressure in young mice was associated with a decline in bone health similar to that seen during the typical aging process. The results also suggest that this bone loss in young mice could be due to increased inflammation associated with high blood pressure.

Study author Elizabeth Hennen, a doctoral student at Vanderbilt University in Nashville, Tennessee, said Medical News Today:

“By characterizing hypertension-induced bone loss in younger mice, we have identified a potential new population at risk for fragility fractures. This means that pediatric hypertension may have significant implications later in life, which have yet to be researched. This research is gaining importance as the prevalence of pediatric hypertension increases.

The researchers recently presented the results at the American Heart Association‘s Hypertension Scientific Sessions 2022 in San Diego, CA.

Osteoporosis is a bone disease characterized by a reduction in bone mineral density and changes in bone structure. These changes involving weakening of the bones can increase the risk of fractures.

Several observational studies have shown that people with high blood pressure or high blood pressure are at higher risk for fractures due to osteoporosis. Moreover, there is also evidence suggesting that certain high blood pressure medications may also increase bone strength and reduce the risk of osteoporotic fractures.

“There is significant clinical evidence to suggest that hypertension is associated with reduced bone quality; however, little research has been done to elucidate how hypertension may contribute to bone health,” Hennen said.

Researchers believe that increased inflammation may be one of the mechanisms that may mediate the association between hypertension and osteoporosis. Previous studies have shown that inflammation contributes to the development of high blood pressure. It involves the accumulation of activated immune cells in the bone marrow which secrete pro-inflammatory proteins.

These activated immune cells and the pro-inflammatory proteins secreted by the immune cells can influence the survival and activity of cells involved in maintaining the balance between bone synthesis and breakdown. Studies suggest that an inflammatory environment in the bone marrow can modulate the bone remodeling process and cause bone loss.

A gradual decrease in bone density and strength usually occurs with aging. The typical aging process is also associated with chronic low-grade inflammation, and this increased inflammation could lead to bone loss.

It is unclear whether hypertension in young animals results in bone loss similar to that seen during the aging process and how aging, hypertension, and inflammation interact to influence bone loss.

To address these issues, researchers at Vanderbilt University compared the effects of hypertension on bone loss and inflammation in young and older mice.

For the study, the researchers used the hormone angiotensin II cause high blood pressure in animals. Angiotensin II is a vital hormone in regulating blood pressure, and dysregulation of the system involving angiotensin II is seen in people with hypertension.

The study involved two groups of younger mice aged 4 months (equivalent to a human age of around 25 years old) and two groups of older mice aged 16 months (a human age equivalent to around 52 years old). Young and old mice received infusions of angiotensin II or a placebo vehicle for six weeks.

Six weeks after treatment, the researchers obtained lumbar vertebrae from young and old mice to assess bone health. They used an imaging technique called microcomputer tomography to assess the strength, volume and stiffness of the lumbar vertebrae.

Induction of elevated blood pressure in juvenile mice using angiotensin II resulted in reduced bone volume, structural integrity, and strength compared to vehicle-treated juvenile mice. Similar to young mice with high blood pressure, deterioration in bone health was also observed in older mice with healthy blood pressure.

Additionally, older angiotensin II-treated mice did not show higher levels of bone loss than older vehicle-treated animals. In sum, young mice with high blood pressure showed similar levels of bone loss to older mice, whether they had typical or high blood pressure.

Dr Daichi Shimbo, a cardiologist at Columbia University in New York, said DTM:

“These data suggest that hypertension can induce osteoporosis. There is some evidence in humans linking hypertension to osteoporosis, so these data in mice are important. Moreover, since the results were observed mainly in younger mice than in older mice, this suggests that it would be important to detect hypertension as early as possible in humans (i.e. i.e. children/young adults).

The researchers then looked at the impact of high blood pressure on the inflammatory response in the bone marrow.

Inducing high blood pressure in young mice using angiotensin II resulted in the accumulation of activated immune cells in the bone marrow. Such activation of the immune response was absent in vehicle-treated mice with healthy blood pressure.

Additionally, the researchers observed an elevated inflammatory response in the bone marrow of aged mice treated with angiotensin-II and vehicle. These results suggest that aging is associated with higher levels of inflammation, independent of high blood pressure.

Such an increase in inflammation associated with aging could be enough to cause bone loss, regardless of blood pressure levels. In contrast, hypertension resulted in high levels of immune response in younger animals, which can then lead to loss of bone volume and strength.

Researchers have found that certain pro-inflammatory factors are elevated in the bone marrow, and understanding how these factors mediate the effects of high blood pressure on bone loss could help develop therapies to prevent osteoporosis in young adults. .

The authors caution that these findings do not establish a causal role for inflammation in mediating the effects of hypertension on bone loss in young animals. They also noted that further research is needed to determine whether these findings in mice can be extrapolated to humans.

“These results suggest that hypertension can induce inflammation, but it is not clear that inflammation is the reason why hypertension induces osteoporosis,” Dr. Shimbo said.

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