Monday, March 10, 1997 | 11:59 a.m.
A University of Nevada School of Medicine study on kidney failure in people with hypertension or diabetes may lead to development of a medicine that will replace dialysis or kidney transplants.
The study is being conducted by third-year medical student Miguel Rivera of Las Vegas, who last week presented his work in Princeton, N.J.
Rivera analyzed mesangial cells, which regulate the flow of blood and urine into kidneys. He theorized that kidney failure and death of these cells in people with hypertension and diabetes is directly related to the flow of calcium into the kidneys.
"We hope this research leads to a medication that can deter calcium from flooding the kidney cells in people with hypertension and diabetes to prevent kidney failure," Rivera said.
In healthy people, extra pressure from strenuous exercise put on the mesangial cells lasts for a short time. The cells stiffen to protect themselves during the stress, then recover.
"We believe that diseases such as hypertension and diabetes exert a constant pressure that forces mesangial cells to stretch, allowing too much calcium to enter," Rivera said.
Then the cells protect themselves, the calcium begins to harden and the cell walls become too rigid to perform, eventually dying and damaging the kidney, he said.
To test his theory, Rivera put about 100 normal human mesangial cells bathed in a calcium solution in each of 100 dishes. He discovered a small, manageable amount of calcium penetrated the cells.
Then he added a hypotonic solution that mimics effects of hypertension and diabetes in kidney cells. Of the 85 dishes usable for the study, Rivera found that all had extensive calcium inside the cells.
"This is the first step in proving our theory," Rivera said. Next, he'll focus on long-term effects of calcium in the mesangial cells to get a clearer picture of what happens.
Rivera performed the study with a grant from a fellowship program in academic medicine for minority medical students supported by Bristol-Myers Squibb Co. The program allows a minority medical student to work with a mentor.
One of 35 gifted minority medical students chosen for the program this year, Rivera's grant helped fund the first phase of his research.
"Miguel's research directly contributes to our understanding of how kidney failure occurs in people with high blood pressure and diabetes," said Nelson Publicover, professor of physiology at the University of Nevada School of Medicine.
"By performing the first human studies on this subject, he will help in the development of potential preventive treatments," Publicover said.
Before medical school, Rivera served as a U.S. Air Force mental-health specialist for seven years. Caring for soldiers in Germany returning from Operations Desert Shield and Desert Storm from 1989 to 1991 fostered his desire to pursue medicine as a career.
On active duty 40 hours a week while attending college, Rivera transferred to a different university each time he was stationed in a new area.
"Maintaining my confidence was sometimes tough," Rivera said. "People would tell me that my age, underprivileged background, variety of colleges attended and Air Force experience would hinder my chances of becoming a physician. Now that I'm in medical school, I found that none of that applies."
After medical school, Rivera plans to complete a residency in primary care and join the faculty of a medical school. He also wants to continue his military career. He hopes to join the Air National Guard and join relief efforts during emergency situations.
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