Pre-Renal Initiative 2025

We are thrilled to announce the completion of another successful year of the Pre-Renal Initiative summer program under the leadership of Co-Director Vivek Bhalla, MD, Co-Director James Brooks, MD, Clinical and Didactics Course Director Pedram Fatehi, MD, MPH, and Career Sponsor Glenn Chertow, MD, MPH.

The program culminated in a highly successful symposium, showcasing the outstanding research of ten talented students who presented their research posters. This annual event highlights the dedication of our young scholars to advancing the field of nephrology and related subspecialties.

About the Pre-Renal Initiative

The Pre-Renal Initiative was established in 2021 with the goal of sparking interest in nephrology and urology among students, particularly those from communities underrepresented in medicine. Within nephrology, race and ethnic minorities are disproportionately affected by chronic kidney disease (CKD).

As Bhalla points out, early exposure to these dynamic subspecialties is crucial to attracting more practitioners and researchers to the field. The initiative aims to address the shortage of specialists in these fields by encouraging students to explore nephrology, urology, and benign hematology.

The 10-week program, supported by funding from the National Institutes of Health (NIH), combines rigorous research projects, engaging lectures, and valuable professional development opportunities. Students participate in twice-weekly lectures led by nephrology, urology, and hematology faculty members, and benefit from seminars, social events, and the opportunity to present their research at both Stanford and an NIH symposia.

Highlights from the 2025 Symposium

Learn more about the 10 showcased research projects

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"Evaluating Cooling Solutions For Core Temperature Regulation And Kidney Injury Risk Reduction In Agricultural Workers" Aitana Allen-Perez, Shuchi Anand Summary: Climate change impacts agricultural workers by causing an increase in heat stress, which may affect their kidney health. By using a battery-powered CoolMitt that circulates water and a cooling bandana, these cooling interventions will be compared against standard workplace protocols. The efficiency of these interventions will be assessed to reveal if core temperature will be reduced and to understand any fluctuations in cystatin c or creatinine levels. Measuring creatinine and cystatin c through phlebotomy will reveal any indication of acute kidney injury or a potential progression towards chronic kidney disease. Based on electrolyte and waste product values from a basic metabolic panel, an anion gap will later be determined for signs of kidney disease or any inability to excrete acids. What the Study Found: Creatinine is the standard for acute kidney injury, where with heat stress, the kidney tubule is the site of injury. However, cystatin c is a marker that reveals how well the kidneys filter waste, and may reveal a quicker detection of AKI, as cystatin c increases more quickly. By measuring the trend of creatinine and cystatin c longitudinally, this may reveal if there are fluctuations that may lessen susceptibility to acute kidney injury and chronic kidney disease, with one of the two cooling interventions, as compared to the control. This result could prove the efficiency of at least one of the two cooling interventions to thus allow for easy implementation for workers to use as they are on the field. Based on the quantitative values, two individuals were determined to be barely within the early-stage kidney disease range, and monitoring eGFR longitudinally can reveal the effect that a certain intervention has on its cohort. Additionally, with values obtained from the basic metabolic panel, as well as the cystatin c results, the anion gap can be calculated by taking the difference of anions and cations to reveal any inability to excrete acids and kidney disease. Why This Matters: This research matters because climate change is increasing heat stress in agricultural workers, which can cause dehydration and cause overexertion to the kidney, to then ultimately affect worker productivity. A past study of 1,225 Californian agricultural workers has revealed that 40% lacked heat illness prevention training. This study also matters because there is no current proactive interaction that reduces heat stress to mitigate the onset of AKI or progression to CKD. What did your experience with the Pre-Renal Initiative mean to you: I learned so much from the lessons hosted during the Pre-Renal Initiative, from different tools and resources to determine kidney dysfunction, to different conditions like nephrotic syndrome and kidney stones, to different markers that are assessed to determine kidney health status. As someone who has learned about nephrology through classes and my participation in UCLA clubs, I have really appreciated the depth and range of nephrology knowledge provided, outside of my surface level knowledge of kidney physiology and incidence rates.

"Examining Strategic Dialysis Initiation Practices Among U.S. Liver Transplant Programs" Aneesh Swaminathan; Allison J. Kwong, MD, MS; Jane C. Tan, MD, PhD; Xingxing S. Cheng, MD, MS Summary: The Model for End-Stage Liver Disease (MELD) is a scoring system used to prioritize liver transplant candidates based on objective laboratory measures that reflect disease severity and waitlist mortality. Components of this scoring system include serum bilirubin, international normalized ratio (INR), serum sodium, and serum creatinine. Although designed to be objective, the current system remains vulnerable to manipulative listing practices by transplant programs. Programs may initiate dialysis prematurely to artificially inflate MELD scores by elevating serum creatinine to its capped maximum value. Strategic manipulation of waitlist priority has been documented in heart transplant, but its existence in liver transplant remains unknown. This study aims to systematically document and quantify the prevalence of MELD-score manipulation via strategic dialysis initiation among U.S. liver transplant programs following the 2020 Acuity Circle policy change, a shift from region-based to radius-based organ allocation. What the Study Found: This study provides the first systematic, national-level evidence of strategic dialysis initiation in response to shifting program incentives and local market competition, particularly following the 2020 Acuity Circle policy change. By documenting these dynamics across different programs and geographies, we seek to inform ongoing ethics and policy debates surrounding equity and integrity in liver transplant allocation, as well as current deliberations over implementing a similar acuity circle policy for heart transplant allocation. We ultimately aim at offering data-driven insights into the need for better aligning institutional incentives with their intended policy outcomes. Why This Matters: MELD-score manipulation through practices such as initiating dialysis in liver transplant candidates without clear clinical indication raises serious concerns about the integrity and objectivity of the current liver allocation system. When abstracted nationwide, such behavior risks precipitating a "race to the bottom," which threatens fairness in organ allocation and trust in both the organ allocation and donation system. What did your experience with the Pre-Renal Initiative mean to you: My summer experience through the Pre-Renal Initiative was my first foray into the exciting world of academic health policy. I am exceptionally grateful to the program coordinators for extending me this unique opportunity and, especially, to my program mentor Dr. Jane Tan for recognizing in me---and from my dual academic interests---a potential interest in health policy research. I thank Dr. Tan for connecting me with a project in a field that I had not specifically asked for nor anticipated in pursuing but have now found a new passion for. Participating in the Pre-Renal Initiative has been one of the most formative and career informing experiences of my undergraduate education.

Working on my health policy project, I developed a new computational and statistical skillset and developed more confident in my abilities to conduct quantitative and independent research. I thank my mentor Dr. Xingxing Cheng for enabling in me this growth by tasking me to carry this project independently, from designing the methodology and data cleaning to performing analysis and making my presentation figures. Of all the other wet-lab and clinical research projects I've worked on before, it was my project this summer that allowed me to see all aspects of the research process. It has been an invaluable learning experience that strengthened my technical skills and my confidence in my ability to perform independent research. I will be continuing the project remotely to finish it.

I also deeply enjoyed the opportunity to interact with Stanford researchers and Nephrology faculty through the biweekly lectures. Even though they were just 1 hour, they were something I'd looked forward to all week. I find clinical nephrology and its practice exciting. It is certainly a field I can see myself going into and enjoying -- especially the basic biology and physiology, which continues to inspire me.

"PSA Variability to Diagnose Clinically Significant Prostate Cancer and Predict Progression During Active Surveillance" Ejemen (Eje) Idemudia; Fernandino L. Vilson; Boya Zhang; I-Chun Thomas, MS; Olubusola Onsunsanya; James D. Brooks, MD; Priyadip Ray; John T. Leppert, MD, MS Summary:
My project explores how variability in prostate-specific antigen (PSA) levels can be used as a potential tool to improve prostate cancer detection and monitoring. We investigated this in two ways: first, by testing if PSA variability could help identify men more likely to have clinically significant prostate cancer at the time of diagnosis; and second, by evaluating whether it could detect men on active surveillance-a management strategy where patients with low-risk prostate cancer are monitored and not treated-that are at higher risk of disease progression and needing to transition to treatment. What the Study Found: This study shows how PSA can provide insights beyond a single test result, offering a deeper, more dynamic picture of prostate cancer risk. By capturing each patient's PSA Average Real Variability (ARV), this approach provides a more complete view of their disease biology-leading to better risk stratification, fewer unnecessary biopsies, and stronger monitoring for patients on active surveillance. Ultimately, PSA variability can guide more personalized treatment decisions, improving patient outcomes while minimizing overtreatment. Why This Matters: This study highlights the value of incorporating PSA variability into routine prostate cancer screening to improve both diagnosis and disease monitoring. PSA testing has long been the cornerstone of prostate cancer screening, but by incorporating PSA variability, we refine this classic tool and gain a fuller picture of disease risk. This way, clinicians can make more informed decisions about when to biopsy, when to treat, and when to safely monitor. This approach has the potential to improve outcomes by catching aggressive cancers earlier while reducing unnecessary procedures for benign fluctuations, ultimately enhancing quality of life. What did your experience with the Pre-Renal Initiative mean to you? Through the Pre-Renal Initiative, I had the chance to explore the fascinating specialty of urology. I was really struck by the depth and variety I found in this specialty, and I'm grateful to have had the chance to explore such a dynamic and rewarding field of surgery. At the same time, the program also opened my eyes to the broader challenges of kidney disease, underscoring the urgent need for continued research and innovation. Altogether, this experience has expanded my perspective on patient care and strengthened my interest in pursuing a surgical career.

"Investigating Genetic Risk Factors for Kidney Disease Using Large-Scale Genomic Datasets" Fiona Chan, Mentors: Dr. Vivek Bhalla and Dr. Vivek Charu Summary: The goal of this study is to identify emerging genetic variants associated with kidney disease using genomic datasets. We built on a case control study, and we focused on conducting a downstream assessment to refine a list of 131 genes with possible association with kidney disease to 7 genes for further analysis. A unique aspect of this research is the integration of genomic data from a commercial genetic testing company specializing in genetic kidney disease referrals with two large health data studies in the US and UK. This highlights an important avenue for genetic kidney disease, and we now present a set of 7 genes with key genetic variants. What the Study Found: Chronic kidney disease and acute kidney injury can cause a decline in kidney function, leading to many symptoms that may impact a patient. Moreover, genetic factors can largely influence severity, disease progression, and treatment. By understanding and identifying these genetic variants, we can better provide a personalized plan of care and open up new discoveries for detection and therapies. Why This Matters:
Genetic kidney disease research paves the way for opportunities for discoveries and treatment innovations in kidney disease care. With over 1 in 7 adults having kidney disease, it only continues to highlight the need to further understand kidney disease and the impact and identification of genetic factors. This research opens up endless possibilities for breakthroughs that one day may assist a patient with their everyday life. What did your experience with the Pre-Renal Initiative mean to you? The Pre-Renal Initiative has been an incredible program both personally and professionally. Growing up while taking care of my mother with FSGS made me very familiar with the impact of kidney disease on people's lives. For this reason, I always loved learning more about the ongoing research and discoveries to both give hope to my family and to motivate us to keep fighting. Through this program, I have had an eye-opening and life-changing opportunity to learn and work with genetic kidney disease research. This research experience was extremely enriching, and I am extremely grateful for my mentors, Dr. Vivek Bhalla and Dr. Vivek Charu, for guiding and mentoring me throughout this journey. Moreover, I had the chance to learn about faculty who are conducting various inspiring research. This experience means the world to me, and I have learned to chase my passions for research. My key takeaways are the research skills I have learned from my mentors as well as the inspiration to continue pursuing research.

"Bone Density and Strength following Parathyroidectomy for Secondary Hyperparathyroidism in Patients with End Stage Kidney Disease James Cao, Mary Leonard, Jeffrey Norton, Glenn Chertow, Kyla Kent, Jessica Whalen, Jin Long, Susan Ziolkowski Summary:

Patients with chronic kidney disease develop over-activity of the parathyroid gland to control calcium levels in the blood, resulting in the thinning and degradation of bone structure, and may require removal of the gland (parathyroidectomy) if activity cannot be controlled with medications. Following parathyroidectomy, "hungry bone syndrome" occurs, in which serum calcium levels decrease and aggressive calcium supplementation is required. Improvements in bone mineral density and cortical thickness have been noted in both primary and secondary hyperparathyroidism. However, the possibility of long-term reversibility of the bone degeneration is still unclear. This one-year longitudinal study follows end stage kidney disease patients on hemodialysis prior to parathyroidectomy and at 3-month and 12-month follow-up, analyzing DXA bone density scans with novel hip structural analysis software. What the Study Found: Following parathyroidectomy, there were significant improvements in bone mineral density (BMD) and BMD z-scores at the hip, femoral neck, and lumbar spine regions. Using hip structural analysis, there were also significant improvements in buckling ratio, and section modulus at the narrow neck and femoral shaft regions, indicating improvement in the hip's ability to withstand force. Subperiosteal bone width did not change while cortical thickness increased and endocortical diameter decreased, indicating bone formation on the inner shell of the cortical bone. Our data reflects a possible reversibility of CKD and secondary hyperparathyroidism-induced damage to bone and cortical thinning. Subsequent work will assess bone biomarkers, HRpQCT, vascular calcification, and isokinetic dynamometry. Why This Matters: This in-progress study will track the recovery of CKD and secondary hyperparathyroidism patients to determine the extent of bone formation and damage reversibility possible with known treatments (parathyroidectomy). This verifies the effectiveness of current medical treatments for these conditions as well as illuminates the body's mechanism for skeletal recovery. What did your experience with the Pre-Renal Initiative mean to you? My experience with the Pre-Renal Initiative was extremely meaningful, both personally and professionally. It deepened my awareness of the human impact of chronic kidney disease, as well as the great impact clinical research can have on lives. Under the guidance of excellent mentors, the Pre-Renal Initiative reformed me as a scientist and researcher. My approach to research was completely refined and I gained valuable skills in communication, planning research logistics, and analyzing health data. Living and working alongside likeminded and motivated students taught me the collaboration needed for research and made for an incredibly fun summer.

"Modeling Immune-Mediated Kidney Allograft Rejection Using ALI Organoids" Phillip Park, Annerose Ziegler, Ken Sutha, Calvin Kuo Summary: Kidney transplantation is the preferred therapy to treat end-stage renal disease, but long-term success is hindered by allograft rejection. A major obstacle in rejection research is the lack of an in vitro model that faithfully recapitulates the renal mechanisms that drive rejection, which could be used to study immune-epithelium interactions and test new drug therapies. To address this need, our lab has developed an air-liquid interface (ALI) kidney organoid model that preserves native epithelium, vasculature, and tissue-resident immune cells. As a first step towards modeling transplant rejection using organoids, we co-cultured kidney organoids (representing donor tissue) with alloimmune natural killer (NK) cells and donor specific antibodies (representing recipient immune response) to mimic immune-mediated rejection. We chose to focus on the innate immune system because while it is a critical driver of rejection, it is understudied compared to the adaptive immune system. We measured rejection in two ways. First, we looked at NK cell activation through expression of CD107a, a marker of degranulation. NK cells demonstrated greater activation when cultured with kidney organoids than when cultured alone, and their activation increased even more when antibodies were added. This reflects a process called antibody-dependent cellular cytotoxicity (ADCC), where antibodies help NK cells kill donor tissue. Second, we measured cell death directly, and found that samples with both NK cells and antibodies had the highest levels of cell death. These findings show that our organoid system can reproduce key features of immune-mediated kidney rejection. With further development, this model could be used to better understand transplant rejection and to test potential new therapies. What the Study Found: Our study is the first to characterize and grow kidney organoids in the air-liquid interface (ALI) system. Kidney organoids grown in this system are unique because they retain not only the native epithelium, but also the stromal cells and tissue-resident immune cells. This makes them a powerful tool to model and study the immune mechanisms of rejection, as well as to test potential new immunotherapies. Ultimately, developing more accurate models of rejection could lead to therapies that extend the lifespan of transplanted kidneys and improve outcomes for patients with kidney failure. Why This Matters: Our study lays the foundation for using organoids to model kidney allograft rejection. In the future, our organoid system could be used to test immunotherapies and uncover new insights about the mechanisms of transplant rejection. What did your experience with the Pre-Renal Initiative mean to you? The Pre-Renal Initiative was an incredible experience that shaped me both as a researcher and as an individual. During my ten weeks in the Kuo Lab, I gained invaluable skills in experimental design, wet lab techniques, and data interpretation. I feel much more confident as a researcher than I did at the beginning of the program, and I owe that to the outstanding mentorship I received in the lab. Beyond the bench, I was introduced to the field of nephrology through lectures with Stanford nephrologists, which broadened my perspective about medicine and sparked a genuine interest in a field I had previously known little about. Lastly, I am so grateful for the friendships made with my fellow peers in the program. Over the two months in the program, we bonded over meals, rock climbing, escape rooms, and much more, which made the summer a fun and unforgettable experience.

"Relationship Among Quality of Life, Ankle-Brachial Index, and Home Time in Chronic Kidney Disease" Samuel Osipov, Sai Liu, Jun Young Lee, Tara Chang Summary: We investigated the relationship among quality of life survey scores, the Ankle-Brachial Index, and Home Time from data taken from a large clinical trial composed of patients with both chronic limb-threatening ischemia and various stages of chronic kidney disease. What the Study Found: Uncovering the relationship between diagnostic testing and patient-centered outcomes may help refine diagnosis, guide treatment, enhance shared decision-making, and ultimately improve quality of life for patients with CKD and CLTI. Why This Matters: This study matters because it can inform how we diagnose and manage patients with peripheral artery disease/CLTI who also have CKD. These patients are among the highest-risk groups for amputation and death, yet the tools providers rely on, such as the ankle-brachial index and quality-of-life surveys, often behave differently in this population due to arterial calcification and competing comorbidities. What did your experience with the Pre-Renal Initiative mean to you? Dr. Tara Chang and her team were absolutely incredible. They made every effort to answer any questions I had, and they were supportive in every step of my project. From them, I took away that research is not linear, and it requires seeking guidance either from a colleague or mentor to push through setbacks. The faculty-led lectures were also informative and pleasant. My favorite lecture was by Dr. Brooks on Urology as a specialty, which was all new and interesting information for me as a prospective medical student. The Pre-Renal Initiative has been an amazing experience overall, and I want to thank all of the program directors and admin (especially Alex!!) for making this summer one where I grew as a researcher and person.

"Assessing the Impact of Chitosan Physicochemical Properties on Antimicrobial Activity and Urothelial Interactions" Sarah Do, Daniel Massana Roquero, T. Jessie Ge, Kathleen E. Mach, Joseph C. Liao Summary: This study investigates how structural properties of chitosan, specifically degree of deacetylation and molecular weight, affect its ability to kill bacteria and its cytotoxicity toward urothelial tissue. The research compares different chitosan derivatives to understand how chemical modifications influence both antimicrobial activity and tissue safety. What the Study Found: By evaluating multiple chitosan derivatives, the goal is to identify formulations that can effectively disrupt bacteria while remaining biocompatible with the urinary tract. Such insights could support the development of safer, more effective therapies to reduce post-surgical urinary tract infections, lower recurrence rates, and improve recovery for patients with kidney stones. Why This Matters: Patients with kidney stones are vulnerable to recurrent urinary tract infections because bacteria form protective biofilms that resist antibiotics. Exploring how to fine-tune chitosan's structure helps us find versions that can break down these biofilms while staying safe for bladder tissue. In the future, this could translate into safer therapies that reduce infection, recurrence, and complications after stone surgery. What did your experience with the Pre-Renal Initiative mean to you? The Pre-Renal Initiative was an incredible opportunity, especially coming in with limited lab experience. It gave me the chance to connect basic science with real clinical challenges while learning how to troubleshoot, think critically, and work as part of a research team. I also appreciated the lectures and shadowing opportunities, which offered a bigger-picture perspective on medicine. Beyond the lab, I built lasting friendships and connections that made the summer both fun and meaningful. This experience confirmed my passion for bridging science and medicine as I move forward.

"A Cross-Sectional Survey of Clinical Practice and Guidelines Adoption for Kidney Stone Prevention" Yunseo Jo, Calyani Ganesan, Lindsey Keo, Maria Montez-Rath, Glenn M. Chertow, John T. Leppert

2025 Pre-Renal Initiative Research Symposium Gallery

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Near-Peer Sponsors (left to right) Steve Zhou, Erica Dhuey, and Anas Tresh

Vivek Bhalla, MD Program Co-Director

Administrative Support Staff (left to right) Alexandra Graver and Kachyee Vang

Learn more about the Pre-Renal Iniative here

2024 Pre-Renal Initiative Learn more about the student research initiatives in the 2024 Pre-Renal Initiative Program!

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