From the article:
Scientists at the University of Edinburgh examined the effects of testosterone on blood vessel tissue from mice. They found that the hormone triggers cells from the blood vessels to produce bone-like deposits – a process called calcification. When the mouse cells were modified, by removing the testosterone receptor, so they could no longer respond to testosterone, they produced far less of the calcium deposits.
The team also looked at blood vessel and valve tissue from people with heart disease who had undergone surgery for their condition. They found that cells from these tissues contained bone-like deposits and also carried the testosterone receptor on their surface. This suggests that testosterone may trigger calcification in people.
Calcification causes blood vessels to harden and thicken, which means the heart has to work harder to pump blood around the body. It is strongly linked to increased risk of heart attack and stroke. Calcification can also affect the heart’s valves, meaning that the valves cannot open and shut properly and may need to be replaced.