Research Interests

Research in my lab focuses on renal and metabolic adaptations to perturbations such as increased blood pressure and prolonged fasting, in either a natural or induced state. Questions regarding electrolyte and water regulation and natural prolonged food deprivation in a variety of models including seals and dolphins help us better understand the adaptations these animals have evolved to deal with these seemingly extreme conditions. Comparative species may also prove to be viable models to address several of the pathophysiological conditions commonly seen in humans such as obesity, diabetes, and cardiovascular disease.

In addition, our lab is interested in the contributions of aldosterone and angiotensin II to the manifestation of hypertension, and renal and cardiovascular disease. We are also pursuing studies that address the link between diabetes and obesity with hypertension. The role of oxidative stress and inflammation in hypertension and diabetes is of research interest as well as the adaptive mechanisms evolved by seals to counter oxidative stress during prolonged fasting and diving- and sleep apnea-induced hypoxia. We have also begun to explore the benefits of certain natural foods such as almonds and pomegranates to promoting cardiovascular, renal and overall metabolic health.

The focus of my dissertation research was on the regulation of kidney function and the hormonal responses to fasting in northern elephant seal (Mirounga angustirostris ) pups. After nursing for approximately one month, elephant seal pups are weaned, and fast for approximately 2 - 3 months on land before entering the water for the first time. Obviously, these animals have adapted to this life history strategy, but my interests focused on the physiological mechanisms that these animals employ to endure the extended fasting period.

One of the most important adaptations elephant seal pups have developed is reducing water loss by decreasing urine output, however the mechanisms involved with urine formation and excretion have not been well defined in this species. Another important adaptation that has allowed these animals to fast for such prolonged periods is a shift in metabolized substrate from protein within the first week to fat for the remainder of the fast. Periods of food restriction and fasting induce dramatic changes in a number of different hormones that help regulate a person's metabolic rate. However, an examination of these hormones in elephant seals is lacking. The intent of this research was to provide a much better understanding of the physiological mechanisms used to regulate kidney function and metabolism in a species adapted to prolonged periods of fasting, and to use this information to help elucidate the biomedical consequences of anorexia, diabetes, obesity, and renal dysfunctions in humans, as well.

Rudy Ortiz's Lab Group

I have also been a strong advocate and proponent for the advancement of underrepresented minorities in life sciences as an attempt to help address disparities in highly qualified and well-trained URMs in biomedical research and related health fields. We have consistently had a large number of undergraduate students in our lab, especially those from traditionally underrepresented groups. Aside from sponsoring a number of URM undergraduate students in my lab, I also participate in the UCSC MHIRT program by sending highly qualified students to work abroad in collaboration with my colleagues at Kagawa Medical University , Japan . Participation of these students has been highly beneficial and has advanced the training of these students. Furthermore, we also sponsor students from regional community colleges that are selected into the BA-STAR program to conduct summer research in our lab and get the opportunity to participate where this opportunity would not otherwise exist.

With a common thread of metabolic disorders, our research comes in a variety of flavors that includes the involvement of many national and international collaborations. Among our international collaborations include colleagues from Kagawa Medical University, Japan, CIBNOR, Mexico, and Universidade Federal Fluminense, Brazil. Our national collaborations include colleagues from the following: SUNY-Buffalo, Tulane University HSC, Sonoma State University, UCSC, UCSF-Fresno, University of Alaska, Fairbanks, and Vanderbilt University Medical School.