February 8, 2008

Disease Link — i on NIH — episode #0010, segment 1

An in-depth report about the condition between chronic kidney disease and cardiovascular disease.


Welcome to “i on NIH”!

Featured in this month’s episode is an in-depth report about the condition between chronic kidney disease and cardiovascular disease, an update on Sudden Infant Death Syndrome, and an i-to-Eye interview with NIH Director Dr. Elias A. Zerhouni about the importance of biomedical imaging.

Narrator: From the national institutes of health in Bethesda, Maryland – America’s premiere medical research agency – this is i on NIH!

Covering health-research topics important to you and the nation, this public service vodcast is your information source from inside all 27 institutes and centers at NIH. Half an hour, once a month, we’ll show you the excitement of advances and the important information that comes from medical research.

And now, here’s your host, Joe Balintfy.

Joe: Welcome to the 10th episode of “i on NIH” – thanks for joining us. In this program, we look into the connection between chronic kidney disease and cardio-vascular disease; we’ll learn how winter months may affect the incidence of sudden infant death syndrome, or SIDS; and for our eye-to-eye interview, we turn to the Director of NIH to talk about the importance of biomedical imaging…

… but first, this news update. Here’s Harrison Wein from the NIH news-desk.

Harrison: Thank you, Joe. In this NIH Research Update, metabolic syndrome, genes and heart disease, and preventing cancer.

One of our recent stories in NIH Research Matters is about metabolic syndrome. Saying you have metabolic syndrome is basically a way of saying you have a higher risk of cardiovascular diseases like heart attack and stroke.

Healthy lifestyle changes are the first line of treatment—weight loss, more physical activity, a better diet and quitting smoking. Medications are the next line of treatment. They can help control individual risk factors like high blood pressure. There are several medications doctors can prescribe for controlling blood pressure in patients with metabolic syndrome.

A new NIH study found that less expensive diuretic drugs may be a better choice than newer, more costly medications. If you have metabolic syndrome, you should talk to your doctor about your options in light of this finding.

You probably know that your blood levels of cholesterol and fats are related to your risk for heart disease. These are collectively called lipids, and scientists know about certain lifestyle factors—like smoking, diet and physical activity—that affect your blood lipid levels. With a new study, scientists are starting to understand the role of genetics. A team that included NIH researchers has now revealed more than 25 genetic variations in 18 genes that are connected to blood cholesterol and lipid levels. Knowing about the genes that can contribute to heart disease could lead scientists to new treatment and prevention strategies.

In another new study, a research team including scientists from NIH and the National Naval Medical Center found that military veterans wounded in 2 specific brain regions during combat were less likely to develop post-traumatic stress disorder than those injured in other areas of the brain. The researchers suggest that a new strategy for treating post-traumatic stress disorder could be to find ways of reducing brain activity in these particular regions.

You can read about these and many other research studies in “NIH Research Matters.” Go to the NIH home page and look for the link on the right-hand side, under “In the News” that says, “eColumn: NIH Research Matters”

In this month’s health newsletter, “NIH News in Health”… You probably know people who’ve smoked their whole lives and thrived well into old age without any sign of lung cancer. And someone else who never went near fruits and veggies but lived a long, full life. When you see things like that, you might think that cancer will come when it comes and there’s nothing you can do about it.

In fact, many people are exposed to things that raise their risk of cancer but never get cancer. Clinical studies involve thousands of people and last for years. They give scientists a far broader perspective on cancer risk and prevention than you could ever get yourself. There are several general lifestyle changes that researchers have proven lower your risk of cancer. Read about these and more in the February NIH News in Health. You can find it at news-in-health-dot-nih-gov.

This is Harrison Wein at the NIH Science Desk.

Joe: Thanks Harrison! February is American Hearth month, but for this report we talked about Chronic Kidney Disease. Why? Here’s Dr. Andrew Narva from the National Institute on Diabetes and Digestive and Kidney Diseases to explain.

Dr. Narva: Well, there is a very close connection between kidney disease and heart disease, which is also sometimes called cardiovascular disease. People with chronic kidney disease are at extremely high risk of developing cardiovascular disease. In addition, people with cardiovascular disease are at high risk for chronic kidney disease. People who have both conditions, both heart disease and kidney disease, have problems that tend to be worse and tend to get worse more quickly. Their kidney disease gets worse more quickly, and their heart disease is also associated with worse outcomes.

Joe: An estimated 3.83 percent of adults aged 20 or older – that’s about 7.7 million Americans – have physiological evidence of chronic kidney disease. Dr. Narva explains that Chronic Kidney Disease is defined in two ways.

Dr. Narva: One is a decrease in the filtering ability of the kidney. The kidney is a filter, and when you've lost about half of your filtering capacity you can be diagnosed as having chronic kidney disease. The second way of being diagnosed as having chronic kidney disease is if you have evidence of kidney injury, even if your kidney filters normally.

Joe: Most people have two kidneys. They are located near the middle of the back. Every day, healthy kidneys filter about 200 quarts of blood and remove about 2 quarts of waste and extra water to make urine. But how do you know if your kidneys are functioning normally?

Dr. Narva: …kidney disease is often referred to as a silent disease. It's said that it's silent because most people have no symptoms until their kidneys are very, very seriously injured. In other words, normally you have a lot of extra kidney capacity, a lot of extra filtering capacity, and you can lose half of that and not be aware of it. You can lose three-quarters of it and may not be aware of it. In fact, many people don't become aware that they have kidney disease until just a relatively short time before they require dialysis. That's why it's very important for people to be screened early if they're at risk. So if you have heart disease, if you have high blood pressure, if you have diabetes, if you have anyone in your family with kidney disease you should be screened, and the screening is very simple.

Joe: Dr. Narva explains that kidney disease is diagnosed with two tests, and followed with those same two tests: a blood and urine.

Dr. Narva: Well, the blood test measures a substance called creatinine, which is a waste product from muscle. That waste product is removed by the kidneys and comes out in the urine. If your kidneys are damaged, the waste product level of creatinine goes up, and we can estimate from that how well your kidneys are filtering. And the result is something called the estimated glomerular filtration rate, which is a long word, but it's something that everyone needs to know. If you ask your doctor what's your GFR, your glomerular filtration rate, he or she should be able to tell you. It's a number. Even though it takes a little explaining to understand what it is, it's a number that you can remember. It's a number that you can compare to your last visit, and it can really help you know how well your kidneys are working.

The other test, the measure of protein in the urine, is a sign that the kidney filter is damaged in some way. Protein is what your body is made of; your muscles, your skin and your hair. You get protein from eating foods like meat, fish and chicken. Those foods are absorbed into your blood, and they're circulating in your body in very small particles. Even though those protein particles are very small, they are too big to pass through a normal kidney filter. So if we see protein in the urine, it tells us that the kidney filter is damaged in some way. And that's very important, because even small amounts of protein in the urine signal to us that you're at risk not only of having more serious kidney injury, but also it's a very good indicator of risk for heart disease.

Joe: According to Dr. Narva, people with kidney disease are much more likely to develop cardiovascular disease than people without kidney disease. In addition, they tend to have worse outcomes if they have chronic kidney disease. Also…

Dr. Narva: It is often hard to sort out because the most important causes of kidney disease, which are high blood pressure and diabetes, are also very important risk factors for heart disease.

Joe: So what are the intervention options for those with high risk factors?

Dr. Narva: A lot of the interventions for the prevention or treatment of high blood pressure and diabetes and kidney disease and heart disease are the same. Notably, life style changes are the same. If you stop smoking, if you lose weight, if you exercise regularly, your blood pressure, your diabetes will get better.

You improve your status if you’re a kidney disease patient, and you’re less likely to progress to heart disease if you reduce those risk factors. Beyond that, controlling blood pressure well, controlling blood sugar, controlling cholesterol benefits both cardiovascular disease and kidney disease. So, therapeutically, as we're doing research you see more of a unity. We try to address these risk factors as common risk factors for all of these different, organ system-based complications.

Joe: Dr. Narva explains that many of those risk factors are researched at NIH.

Dr. Narva: NIDDK, The National Institute of Diabetes, Digestive Disorders and Kidney Disease covers a range of health problems that are all quite related, and it's a spectrum of disease that begins with obesity, which leads to diabetes, which leads to diabetes complications, including cardiovascular disease and kidney disease. These are things that we study separately. Increasingly we make an effort to link these conditions and work together, although obesity is primarily studied in the Digestive Diseases Division and diabetes studied in the Diabetes and Endocrine Division and kidney disease is studied in the Kidney Division. It's significant that these divisions work together, and in fact, all are increasingly working more closely with the National Heart, Lung and Blood Institute, which has, at its main focus, heart disease.

Joe: For more information on Chronic Kidney Disease and the link to cardiovascular disease, visit the National Kidney Disease Eudcation Program’s website at www.nkdep.nih.gov or call toll free, 1-866-4-KIDNEY.

Joe: Up next, we turn to an expert from the National Institute of Child Health and Human Development. Marion Willinger is the Special Assistant for SIDS, or Sudden Infant Death Syndrome. We talked about how common the syndrome is, and why it’s important to talk about in winter months.

Willinger: Right now, there are about 2,500 babies who die each year from Sudden Infant Death Syndrome and SIDS is defined as the sudden death of an infant under one year of age that is unexplained after a full death investigation. That includes the autopsy, review of the family history, an examination of the scene. So these deaths are a surprise. Typically it’s a baby that’s put to bed and then when the parents go to wake the baby for feeding, the baby is no longer breathing. It turns out that there appears to be a rise in the incidence of SIDS in the winter months, fall/winter months compared to the rest of the year.

Joe: So what are some things that folks should keep in mind around the winter months?

Willinger: Well, one of the things that happens in the winter months is that babies tend to get more blankets on, or heavier clothing on. The parents feel they should keep the room warm, the baby warm. And overheating a risk factor for SIDS. It increases the possibility that a baby will die of SIDS. So it’s important that you don’t over-bundle the baby either with clothes or with blankets, that you don’t overheat the room, that the baby feels cool to the touch. The baby should not feel hot to the touch. And this is particularly the case, it’s very often when children are sick, and they’re running a fever, parents feel they need to cover them and make sure that they take the best care they can. Well, it turns out that when a baby has a fever and they’re sweating, they want to exchange heat. You want them to lose heat. So when a baby has an infection, you don’t want to over-bundle them either. Again, and studies have shown that the combination of a fever with heavy bedding even increases the risk more. So those are some of the things.

Joe: What about during those winter months when people take their kids outside and they put on snowsuits and bundle up their babies. Any tips?

Willinger: When you come back inside and it’s not cold, as cold inside as it outside, and the baby is asleep, you’ve just taken the baby for a walk, you want to make sure that you remove the warm clothing. Take the hat off the head because the head is where babies exchanges heat. And if you keep that head covered then they’re not able to exchange their heat and release the heat. So you want to take hat off, unzip the snowsuit, ideally take them out of the warm clothing while they’re sleeping.

Joe: What do parents need to remember then, whether its winter months, or all year round?

Willinger: It’s a recommendation of the American Academy of Pediatrics, and it’s promoted by our Back to Sleep Campaign, a National Public Awareness Campaign, that all babies should be placed to sleep on their backs.

You want to make sure that their head doesn’t have any possibility of being covered. So you don’t want to use any heavy quilts or comforters in the crib. If you are going to use a blanket, make sure the blanket is tucked under the armpits and under the mattress so the baby can’t squiggle underneath, because you know how babies love to move in their sleep, even the very little ones. Ideally, you’d like, in the winter months, if you keep the room cool, you want the baby to be in a blanket sleeper, then you don’t even have to worry about the use of blankets and the possibility that their face gets covered. There shouldn’t be any pillows in the crib, soft stuffed animals that they can get their face buried in. All these -- having their face buried or covered is a significant risk for SIDS whether or not the baby is on their stomach or on their back. So even though we know back sleeping reduces the risk, to keep the risk minimal, you want to make sure the head does not stay covered.

Joe: To summarize, what are some of the main risk factors for SIDS?

Willinger: The most well-established risk factor for SIDS is a baby sleeping on their stomach or a baby sleeping on their side because side is a very unstable position and they’re at greater risk of rolling to their stomach. So one of the best preventive strategies and best documented strategy we have is for babies to be placed sleep on their back, during all sleep periods. That includes night and nap time, and by all care providers, daycare providers, babysitters, grandparents, parents. So we recommend that strongly and since back sleeping has become the norm in the United States, the SIDS rates have been dropped by half. So it’s a very powerful intervention. It’s an intervention that’s been successful all around the world.

The next thing is to keep your baby in a smoke free zone. And that’s before birth, that is while you’re pregnant. Smoking during pregnancy is another major factor for Sudden Infant Death Syndrome. And as well as a baby living in an environment where other people smoke, so we recommend keeping the baby in a smoke free zone.

For a mattress, you want the baby, a baby -- soft bedding is a risk factor for SIDS as well, because it is compressible and their face can mold into the bedding. So we recommend the baby be placed to sleep on a firm mattress. We also say that it’s very important that the baby be kept in a separate sleep environment, on a firm mattress. Now, there have been studies that have shown that the risk of SIDS is reduced if the baby is sleeping in the same room as the parents. But what -- there are also studies that have shown that sleeping in the same bed as the parents increases the risk. So we say, if you want to bring your baby into bed to cuddle, comfort, breastfeed, bond, we’re all for that, but when you’re ready to go to sleep, place the baby in their own sleep environment. You should not be in bed with the baby if you’re the least bit sleepy or the least bit drowsy. And the baby should have their own place to sleep and it could be a crib in your room, a cradle, whatever.

The other thing that a recent piece of information that we have that has come out in the most recent recommendations from the American Academy of Pediatrics is to try using a pacifier with the baby. There have been many studies around the world that have shown that babies who use pacifiers are at much reduced risk of Sudden Infant Death Syndrome. Now we say that establish the breastfeeding in those early months and days. Once breastfeeding is established, if the baby is willing to take the pacifier, then use it. Some babies won’t, and it’s not worth trying to force it on them, but it’s certainly something to consider using.

Joe: For more information from the National Institute of Child Health and Human Development visit www.nichd.nih.gov and search for Sudden Infant Death Syndrome. There is also a national resource center that you can call toll-free: 1-800-370-2943. The NICHD has provided many thousands of pieces of information regarding Sudden Infant Death Syndrome and the Back to Sleep Campaign across the country, both to individuals, to community organizations, state campaigns. There are pamphlets and videos available, free of charge.

Joe: Now for our I-toEye interview, we are pleased to have Dr. Elias Zerhouni, Director of the National Institutes of Health. A leader in the field of biomedical imaging, we talked about the importance of CAT scans, MRI’s and the science of imaging in general.

“What do you think is the most important information the American public should understand about biomedical imaging today?”

Zerhouni: I think that imaging is really a science that has come into its own, not only over the past 30 years, but it’s currently undergoing a tremendous revolution. The reason is that it’s addressing a very fundamental need in medicine. In the past, to find out what was going on in the body, you had to do surgery. So in many ways, the dream of scientists in imaging like myself was, how can you peek into the human body without destroying it, so it’s nondestructive? And that was the impetus for my research in CAT scanning and MRI over the past 30 years and it has made a revolution in how we diagnose disease, how we treat disease. But going forward, what people are realizing is that in biology, interactions, whether it be DNA or RNA and molecules and another one, the cell within the cell, or an organelle within a cell or a cell with a cell or within tissues, all of these interactions are localized in space. And to extract that information you need what we call imaging. So, imaging is going to work over the next 40 years to try to unravel the mysteries of how molecules interact, how cells interact, how tissues interact. Imagery is going to be even more important not just for medical applications, for fundamental research and for understanding biology.

“What’s your view about the value of CT scanning specifically in detecting certain cancers?”

Zerhouni: So, basically when you look at an imaging technique, essentially what you have is a way of looking at biology, looking at anatomy and structure and function in an indirect way. And whenever you have an indirect technique, what you really want to know is how accurate it is. And you don’t want too many false negatives, where you are missing something, or false positives, where you are seeing something that you think is a disease. And that’s why CAT scanning has been developed to detect lesions in organs like the lung or the rest of the body. And we’re developing other tests, like ultrasound for example, to look at interuterine pregnancies and so on. So, the value has increased over time. Mammography to look at early cancers.

But every time you do this you have to be very careful, because the value of the test depends on how accurate it is, and to find that out you need to really do very rigorous trials. It’s not enough to believe that something works; you have to prove that it works. So that’s what I think is important here, is we have to do that research to provide the American public with the very, very scientific evidence-based answer rather than opinion-based answer.

“What do you see as current and long-term benefits of moving forward the technology of science of MRIs?”

Zerhouni: My work has been directed fundamentally at the intersection of physical sciences, mathematics, physics, engineering and biological sciences. Now, I profoundly believe and this is -- this was my work all along, that it is necessary for you to be able to quantitate what happens in biology. It’s not enough to know that one molecule interacts with this one. How much does it interact? When does it interact? Or, this cell interacts with that cell. You really need to have quantitation.

So my work has been from the very get-go to bring in into biology rigorous quantitative techniques at all levels of imaging, whether it be human imaging with you know, trying to diagnose disease in the hospital, or in the laboratory. So that is, in my view, the key to the future. Science advances because it has better tools that can quantitate exactly what happens in vivo, at the location where it happens, and that’s what imaging is all about, after all. It’s to localize information or extract information, do something about that information, and that’s where we are right now.

“What first sparked your interest in the field of radiology and medical imaging?”

Zerhouni: It’s very interesting. It’s a very good question, because at the time when I became interested in radiology, radiology was a backwater field. It was not very prestigious. And the reason I became interested is because A, I had a background in physics and math. I loved that. B, I had an interest in medicine. C, I had an uncle who was a radiologist and he said, “You know, you might be able to marry those two things.” And then one day he showed me the very first CAT scan that was obtained in the world. It was a grainy image. It was terrible, and 99 percent of the people looking at this said this has no future. But when he showed it to me and he told me how it was acquired, you know, with an x-ray that goes around with a computer that takes the data, I said, “This is it. This is something I think I can contribute to.” So that was my interest. My interest was this combination, if you will, of a dream that in fact you could peek inside the human body without destroying it.

“What do you see as the long-term opportunities and benefits of this new era in biomedical imaging?”

Zerhouni: Well, to me the new era is because we are in need of understanding at all scales, from angstrom, you know at the molecular level, to atoms, to molecules, to cells, to tissues, exactly how the complex biological interactions that make health or disease really work. And, imaging is fundamentally a tool to extract biological information or do something about that at all scales. So, whether it be, you know, electron microscopy or CAT scanning or mouse imaging or human imaging, all of that has one fundamental common thread, and that is that now biologists know that to understand biology you really need to know what happens inside too, in vivo, and hopefully without you destroying the system, but by understanding how it really works.

“How do you think the NIH is prepared to take advantage of this new biomedical imaging era?”

Zerhouni: I think we’ve seen an explosion actually of new ideas, new technologies. For example, one of the fields that has advanced a lot right now is the idea that you could combine a molecule that sends a light, fluorescent molecule, with imaging that doesn’t rely on x-rays, like CAT scanning, or radiation or radio waves, like MRI, but relies on optical imaging. So, now you have the combination of digital optical imaging, like the cameras you have to take pictures, in the laboratory with a probe that is brought into the tissue or the cell to highlight one molecule.

So, one example, NIH and its researchers, Dr. Jennifer Lippincott-Schwartz and her colleagues came up with a technique called photo activated light microscopy. What it is is that she -- Dr. Lippincott-Schwartz and her colleagues can identify a specific molecule. Why? Because they can actually tag the molecule with another molecule that emits light. So as that light comes out, it’s picked up by the microscope. But, it’s controlled. In other words, they can -- they can themselves trigger the light. So that means that you can wait and then when something happens you can trigger the light, say where did it happen in this cell? How did it happen? And that, I think, is going to be an enormous revolution in the way we understand biology in health and disease.

“Do you believe that NIH and other imaging pioneers will have the funding to fulfill the promise of these technologies in the U.S.?”

Zerhouni: Advanced technologies are not cheap in general when you start. So when I started in my field, many people told me, “Don’t go there. It’s really going to be a dead end. It’s so expensive.” The first MIR scanners cost $3 million. And it cost you -- this was 1980. So it’s the equivalent of 15 million today. And in those days, you could examine maybe three patients a day. It took me three hours to do my first examination in CAT scanning and three hours to do it in MRI when I worked in the field. What has happened over the years is just like in computer or cell phones. Every year, the cell phones have become more powerful, the computers have become more powerful, and you’re paying less and less. So, technology is very expensive at the beginning, but when it’s successful, good technologies tend to decrease its price and its cost.

That’s what is happening in imaging. Today you can have a very, very powerful CAT scanner that can do 50 patients a day with one patient in two minutes, with very powerful computers, that cost you in real dollars, in real dollars, it cost you maybe five times less than it used to. So, it’s the same thing when you think about new technology. The first prototypes are always expensive, and you need to support that. You need to really find ways, because if you don’t then all the possibilities of that field will never be explored.

“What do you think is particularly important to remember about imaging technology?”

Zerhouni: I think that the key today in science is to understand the complexity of biology. That complexity is actually much greater than we thought even 20, 30 years ago, and as we’ve discovered more, we need more information at the local level. That’s why imaging has become so important, in all its dimensions. But more importantly I think to me, I wish I was 28 years again, or 30 years old again, because even though I had the fortune, the good fortune of seeing an explosion and a real rebirth of -- birth of imaging, I think there’s going to be another fascinating, fascinating period of time here in the next 20, 30 years where imaging is going to be even more central to our understanding biology than ever.

So, it’s an exciting time to get in, and I would encourage young scientists to get in there. The thought, though, is to be good in imaging you have to really be good at multiple disciplines. So you have to really train yourself to be able to work with people that are different than you, and that was my message. My message is, break barriers between disciplines. Chemistry has to work with physics, has to work with biology, has to work with medicine and surgery and all that, and it’s an exciting way of looking at science. And, that’s also a difficult way. So my message is, this is a field that is rocking and rolling right now, and wish we can excite some young minds to get into it, like we have already.

“Visit www.nih.gov/about-nih/who-we-are/nih-director for more about Dr. Elias Zerhouni and NIH.”

Joe: This interview also appears in the Medline Plus magazine. To see that publication of the National Library of Medicine, visit their website at www.nlm.nih.gov. Thanks again to Dr. Zerhouni and all the NIH researchers that have taken time to talk with us for i on NIH. That wraps up another episode. Please be sure to tune in again next time. We’re working on stories about alcohol abuse, malaria and much more. Thanks for tuning in. For i on NIH I’m Joe Balintfy.

This page last reviewed on April 20, 2015