Advancing Kidney Health Through Science and Mentorship

A Q&A with Joachim Ix, M.D.

With a deep commitment to research and mentorship, Joachim Ix, M.D. professor of medicine and chief for the Division of Nephrology-Hypertension at UC San Diego School of Medicine, has shaped research careers and scientific progress far beyond his own division.

Ix, who grew up in San Diego, attended UC San Diego for his undergraduate degree. He then went on to medical school at the University of Chicago Pritzker School of Medicine, followed by residency and fellowship training at UC San Francisco. He returned “home” to UC San Diego as a faculty member in 2007.

The School of Medicine spoke with Ix to learn a bit more about his path to medicine and his current research and mentorship interests.

What first drew you to pursuing a career in medicine?

It was clear to me at a young age that I was adept at science and math, and yet happiest when interacting with others. I really wanted to use my abilities to maximize benefits for those around me, and to spend a good deal of time with the experience of caring for others.  Medicine is a life of service, and that really resonated with me. I didn’t find my passion for science until much later in medical training.

Your work on the tubule paradigm, and its extension to hypertension management, have been called “practice changing” throughout medicine, tell us about this work and its potential impacts.

Our kidneys are responsible for removing waste from our blood. The current clinical tests for kidney health focus on the filtering function of the kidney but do not give insights into the health of the rest of the kidney. The tubules, which are something akin to the “worker” cells in the kidney, do the hard work of processing urine to retain the nutrients our bodies need and eliminating toxins we don’t need. We’ve developed biomarkers (blood, urine and imaging) that give us insights into the health of this part of the kidney. Sometimes the “filter” markers get worse due to changes in kidney blood flow from certain medications including medications used to lower blood pressure. This leads to concern among clinicians because they can’t tell whether the kidneys are actually being damaged or if the change simply reflects a harmless, temporary shift in blood flow to the kidneys. Often beneficial medications are stopped because of this. Our tubule markers have proven useful to differentiate when these changes are benign and blood flow related, meaning beneficial medications can be continued, versus more harmful intrinsic damage to the kidneys. Intensive blood pressure lowering was proven to lower cardiovascular disease events like heart attacks and strokes and improve survival but was worsening “filter” markers. We showed that this was due to benign blood flow changes, so there was no real kidney damage or concern. This work led several international consensus guidelines that drive practice in cardiology and kidney medicine to advocate for more intensive blood pressure lowering with less concern for kidney harm.

I’m excited that our work has had real world implications for the many people with hypertension worldwide, but the tubule markers should have similar ability to differentiate benign from damaging kidney changes when evaluating other drugs and treatments, and I’m looking forward to addressing those pressing needs as our research moves forward.

Which of your accomplishments at UC San Diego are you most proud of?

While I’m excited about my direct care of patients, and my research discoveries, I’m by far and away most proud of mentoring trainees and junior faculty. Having the opportunity to teach junior investigators about how to craft a research idea into a meaningful project has been the joy of my career. Not only does this work develop physician-scientists that will make important impacts across many years of their careers, but I’m convinced that this work will improve the lives of people living with kidney disease for many more people than those that I can see individually as a physician.

What advice would you give to younger physicians or scientists about staying motivated or inspired?

First, being a physician is an amazing privilege. The challenges faced by patients are the key driver of my research ideas. I would advise younger physicians to stay curious. Question why we do things certain ways and always think of opportunities to do things differently.

What is something that people might be surprised to learn about you?

Outside of work, I love running and recently qualified to run the Boston Marathon. Finally, none of my accomplishments at work would’ve been possible without the support and dedication of my lovely wife, Nicole. I am forever grateful to her for enabling me to pursue my career and make lasting changes for people living with kidney disease.