Dietary changes limiting certain amino acids may help slow disease progression in pulmonary hypertension, researchers say. Kathrin Ziegler/Getty Images
  • About 1% of the world’s population lives with pulmonary hypertension, which currently has no cure.
  • Researchers say dietary changes that limit the amino acids glutamine and serine may help slow disease progression and improve the effectiveness of current medications.
  • Scientists have also developed a new noninvasive diagnostic test for pulmonary hypertension based on their findings.

Researchers estimate that about 1% of the world’s population lives with pulmonary hypertension — a condition causing high blood pressure in the blood vessels in the lungs.

There is currently no cure for pulmonary hypertension. Treatment options — medication, surgery, and lifestyle changes — can help manage symptoms and prolong a person’s life.

Now, new research has examined the effects of dietary interventions on pulmonary hypertension.

A recent mouse study published in Cell Metabolism shows that dietary changes limiting the amino acids glutamine and serine may help slow disease progression in pulmonary hypertension and improve the effectiveness of current medications.

Stephen Y. Chan, MD, PhD, co-senior author of the study and Vitalant Chair in vascular medicine and professor of medicine in the Division of Cardiology at the University of Pittsburgh School of Medicine, told Medical News Today:

“Contrary to a popular misconception, pulmonary hypertension is a prevalent condition with often limited therapeutic options. As such, there is still a 50% mortality rate within 5 to 8 years of diagnosis. While there are new exciting therapies recently approved for the treatment of pulmonary hypertension, we are far from a cure, and our patients are desperate for better therapies to improve mortality rates and quality of life.”

Chan said they decided to look for a link between diet and pulmonary hypertension when they observed that diseased cells called fibroblasts of the lung blood vessels in pulmonary hypertension are surprisingly “hungry” for the amino acids glutamine and serine.

“Our data later showed that this hunger comes from the need (for) fibroblasts to increase collagen production and deposition in and around the blood vessels to stiffen them in disease,” he continued.

“When we cut off that amino acid supply or prevented the use of these amino acids for collagen production, we could reduce collagen production, vessel stiffening, and worsening of pulmonary hypertension.”

Chan and his team used a mouse model to test their theory. When the mice were administered drugs that lowered their cellular uptake of glutamine and serine, the pulmonary hypertensive blood vessels were relieved of their craving.

Additionally, researchers found the lack of glutamine and serine stopped the production of excess collagen, which would lead to lung blood vessel stiffening and impaired function.

Through the research team’s findings regarding serine and glutamine, they were also able to develop a new diagnostic test for pulmonary hypertension.

The test uses positron emission tomography (PET) scan technology and a glutamine imaging tracer to track where glutamine goes in the body. Cells “hungry” for glutamine distinguish themselves on the PET scan, helping doctors with making a diagnosis.

“One of the crucial obstacles in managing pulmonary hypertension is that the diagnosis requires an invasive test called cardiac catheterization, where a long hollow tube is inserted into the blood vessels of the neck,” Chan detailed.

“That catheter is then threaded all the way down into the heart and lungs to measure pressure directly. Not every medical center has this capability, particularly those in more rural or isolated settings, and this limits the ability to appropriately identify and treat patients with this disease.”

“While we use some noninvasive imaging studies like MRI and ultrasound in managing the disease, they are not sufficient to make the diagnosis,” he continued. “Thus, accurate and early diagnosis of pulmonary hypertension is crucial, and there is a clear unmet need for developing better noninvasive diagnostic technology.”

“Our data was only performed in animals with experimental pulmonary hypertension,” Chan added. “We are actively recruiting for a clinical trial at our institution that is testing this new PET technology in patients with pulmonary hypertension.”

— Stephen Y. Chan, MD, PhD, co-senior study author

Chan said that for the first time, researchers have proof that specific dietary adjustments — reducing glutamine and serine consumption, in particular — may serve as an effective way of treating pulmonary hypertension.

“It opens up a new way that we could manage this disease, because now — instead of just relying on medications and transplantation — there are possibly effective lifestyle interventions,” he continued.

“For patients with pulmonary hypertension, avoiding foods rich in serine and glutamine, or eating foods with these amino acids depleted, might improve symptoms, reduce disease progression, or bolster the effectiveness of current medications,” Chan explained.

However, Chan did urge caution in over-interpreting their findings at this stage.

“Our work fully restricted all glutamine and serine from the rodent diets which led to improvement of pulmonary hypertension,” he said.

“We view this finding as (an) important proof-of-concept that dietary maneuvers can be effective as therapies in this deadly disease. However, this level of absolute restriction would not be feasible in a normal human diet, and we certainly do not recommend that our patients attempt to do so at this time.”

“More work is needed to determine if lower levels of amino acid restriction have the same therapeutic effect and/or if more feasible and safe dietary maneuvers could bolster current treatments to promote even better improvement of (the) disease,” Chan added.

After reviewing this study, Cheng-Han Chen, MD, a board certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, told MNT that a dietary approach to improving pulmonary hypertension is a novel approach that could be more accessible to people with pulmonary hypertension as a form of treatment.

“Pulmonary hypertension is a complex disease that could have many different causes,” Chen explained.

“Many of the causes are not easily treatable with our current therapies. This type of research has the potential to provide new targets for medications that could improve the prospects for our patients with pulmonary hypertension.”

However, Chen said we are not yet at the point where people should adjust their diets specifically for glutamine and serine based on the results of this study.

“I advise all patients to eat a well-balanced, heart-healthy diet. The next step should be to see if these findings apply in humans, not just in mice. They probably will be looking at clinical studies to evaluate the effects of diet, specifically glutamine and serine intake, on pulmonary hypertension in those individuals.”

— Cheng-Han Chen, MD, cardiologist

MNT also spoke with Monique Richard, a registered dietitian nutritionist and owner of Nutrition-In-Sight, about this study.

Richard explained that amino acids are the building blocks of protein. Foods rich in amino acids include animal and plant proteins, grains, and legumes with the richest sources, most bioavailable — meaning the body can use efficiently.

“In practice, we often observe an excess intake of animal proteins from those who have hypertension, cardiovascular disease risk, chronic obstructive pulmonary disease (COPD), and other related conditions, as well as contributory factors related to lifestyle choices such as minimal activity, smoking, alcohol intake, poor sleep hygiene, (and) hydration status,” she said.

For those worried about their glutamine and serine intake, Richard advised meeting with a registered dietitian nutritionist (RDN) to fully assess diet composition and intake appropriate for an individual’s needs.

“An RDN will also assess (the) overall balance of dietary and lifestyle factors that influence health in conjunction with the person’s genetics and current physical state allowing for specific and personalized recommendations to be given,” she continued.

“There are a lot of apps and tech platforms that can help assist in deciphering amino acid profile intake, but once we start reducing intake down to building blocks of protein, micronutrients, and that level of scrutiny, we begin to lose sight of the bigger picture and all the factors that beautifully harmonize to produce the symphony of health and vitality.”

— Monique Richard, registered dietitian nutritionist

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