Scientists have found that long-term use of common medications for high blood pressure can severely damage the kidneys’ ability to filter and clean the blood. This important discovery could lead to improved management of high blood pressure and other blood vessel-related diseases.
Researchers at the University of Virginia School of Medicine have elucidated how the prolonged use of frequently prescribed medications for high blood pressure can impair the kidneys’ capacity to filter and purify blood. This revelation might lead to enhanced strategies for treating high blood pressure and various vascular conditions.
The medications in question are known as renin-angiotensin system (RAS) inhibitors. These drugs function by blocking the action of the renin enzyme, which relaxes blood vessels and facilitates smoother blood flow. They are commonly prescribed as initial treatments for hypertension (high blood pressure). However, using them over a long period can inflict serious damage on the kidneys, leading to scarring and significant changes that shift the organs from filtering blood to producing more renin.
As a result, the kidney loses its ability to remove impurities from the blood, becoming what UVA researchers call a “pathological neuro-immune endocrine organ,” which can lead to major health complications. Nevertheless, they believe that their findings can help uncover methods to safeguard the kidneys and enhance the treatment of hypertension.
“The most widely used and thought to be safe blood pressure medications may actually harm the kidneys,” explained researcher R. Ariel Gomez, MD, from UVA’s Child Health Research Center. “It’s crucial to gain a precise understanding of the long-term impact of RAS inhibitors on kidney function.”
Managing High Blood Pressure
High blood pressure impacts over 1.3 billion individuals globally. This condition places extra strain on the heart and can result in a range of serious health issues, such as strokes, heart attacks, kidney injury, and vision impairment.
The renin-angiotensin system (RAS) is essential in controlling blood pressure levels. Renin is a hormone enzyme produced by kidney cells that respond when blood pressure decreases.
RAS inhibitors are commonly used effectively for managing high blood pressure. While these medications are considered safe under medical supervision, patients are typically advised to consult their doctors if they experience symptoms indicating potential kidney damage, such as decreased urination, swelling in the legs or feet, or seizures.
The detrimental long-term effects of RAS inhibition on the kidneys are well-documented; however, the exact causes have remained unclear. The new findings from UVA provide clarity: Excessive stimulation of the kidney’s renin-producing cells prompts these cells to revert to an immature, invasive form. In this altered state, the cells lining the small kidney arteries grow disproportionately large. They begin producing more renin and other substances, resulting in new nerve growth, an accumulation of undeveloped smooth muscle cells, scarring around the small blood vessels (arterioles), and infiltration of immune cells. Ultimately, this leads to what the researchers describe as “silent but serious” vascular disease.
“Our 3D imaging distinctly demonstrated that long-term RAS inhibition causes nerve overgrowth in renal arteries, alongside arteriolar enlargement and infiltration of immune inflammatory cells,” stated researcher Manako Yamaguchi, PhD. “This interplay between neuro-immune-endocrine factors increases renin production to maintain blood pressure balance; however, the severe enlargement of arterioles compromises the kidneys’ filtration capability.”
By gaining insight into the harmful changes occurring in the kidneys, researchers are now poised to discover strategies to prevent this damage. This could pave the way for safer treatment options for managing high blood pressure, they hope.
“Our next objective is to thoroughly investigate the interactions among renin cells, smooth muscle cells, nerves, and inflammatory cells under RAS inhibition,” added researcher Maria Luisa S. Sequeira-Lopez, MD. “These findings could lead to new strategies for preventing negative effects in the treatment of hypertension.”
