Let the Research Guide You

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Cristian Puerta, MD, came to UC San Diego in 2022 to conduct research in the lab of Patricia Thistlethwaite, MD, PhD. He began researching cardiothoracic disease biomarkers and, after years of hard work, he became one of three first authors on a study about a new biomarker that can diagnose idiopathic pulmonary arterial hypertension (IPAH), a genetic disease that thickens the arteries, causing an increase in blood pressure and heart failure. The results were published in Nature Medicine on Jan. 9, 2026.

The Department of Surgery interviewed Puerta about joining the UC San Diego team and his commitment to academic research.

What brought you to UC San Diego?

I grew up and went to medical school in Tijuana, Mexico, and completed my internship rotations and social service doing research in Mexico City. As a medical student being educated across the border, I always heard that UC San Diego was one of the most important and prestigious biomedical research centers in the United States. When I visited the campus, I saw the quality and academic ambiance of the institution and knew it was something I wanted to be a part of. So, when I was applying for research positions in the United States, UC San Diego was my first choice. After two years of research, I joined the general surgery residency program and am now a first-year resident.

Why did you join the Thistlethwaite Cardiothoracic Surgery Lab? 

I applied to the Thistlethwaite Cardiothoracic Surgery Lab because it was specifically focused on idiopathic pulmonary arterial hypertension (IPAH) biomarkers. IPAH is a genetic disease that makes your arteries thicker, increasing blood pressure and causing heart failure.

What did your recent research reveal? How can these findings potentially impact patients?

We recently found that the NOTCH3-ECD is a protein biomarker (a measurable indicator of disease) that can point to the presence and severity of IPAH. Right now, IPAH is often diagnosed late — once patients are identified as having it, they usually already have symptoms of heart failure. There are very few treatment options at this late stage.

We think the NOTCH3-ECD biomarker is going to be a very powerful screening tool to prevent this. It can tell us if a patient has or doesn’t have the disease, and if the treatment we are giving them is working. Our team plans to continue researching the NOTCH3-ECD biomarker and eventually develop an affordable, routine and widely available IPAH blood test. This will make it easier to diagnose patients and start treatment early, giving them a much better prognosis.

You were a co-first author on a manuscript published in Nature Medicine. How does it feel to have accomplished such an achievement?

I feel very grateful for my mentor, Patricia Thistlethwaite, MD, PhD, and our research team. This was a joint effort. I pursued research because I wanted to make a big impact, moving medicine forward and making discoveries for the scientific community and for patients. I feel truly happy to be making the impact our team and I set out to make. I also think this is a big step in my career. Now that I have been a part of such a big study, I have the experience to replicate it for other diseases and continue sharing my experience in medicine.

What advice would you give aspiring researchers?

Research will teach you how to be open to understanding how something works. Sometimes, medical students or other trainees feel that they are not in the field they want to be in, or they are not enjoying what they are doing. I would say that every lesson is an opportunity. Be open to learning. Anything you learn, you can apply to other aspects of research and clinical practice. We have a lot of work ahead of us — we need to improve our physical skills, optimize treatment and be better for patients.