Kolff, Willem

Willem J. Kolff

University of Utah School of Medicine

Scribner, Belding

Belding H. Scribner

University of Washighton

For the development of renal hemodialysis, which changed kidney failure from a fatal to a treatable disease, prolonging the useful lives of millions of patients.

This year’s Lasker Clinical Medical Research Award honors two scientists who changed kidney failure from a fatal to a treatable disease. By developing the artificial kidney and devising a system for repeating hemodialysis over a period of months and even years, Willem Kolff and Belding Scribner, respectively, have prolonged the useful lives of millions of people.

The fate of kidney patients has undergone a revolution in the last half century, due in large part to Kolff’s and Scribner’s seminal contributions. The kidney filters metabolic byproducts from the blood, and when it fails, patients suffer from a variety of symptoms, including weight loss, nausea and vomiting, gastrointestinal hemorrhaging, itching, lethargy, convulsions, and coma. Without treatment, death ensues. Hemodialyzers replace the cleansing capabilities of the kidney, and although the organ performs other physiological tasks as well, the machine’s ability to extract impurities bestows vitality upon formerly doomed individuals.

Darnell made his first major finding 40 years ago, soon after researchers studying bacteria uncovered a phenomenon that every modern biology student knows: The nucleic acid messenger RNA (mRNA) serves as a short-lived copy of its close relative, DNA, allowing the information contained in the cell’s genes to be translated into proteins. In the genetic regions that encode proteins, each trio of DNA building blocks (deoxyribonucleotides) corresponds to a trio of RNA building blocks (ribonucleotides), which in turn guides a single amino acid into the growing protein.

As scientists were marveling at the elegant simplicity of this bacterial system, Darnell was tracking RNA inside mammalian cells. Soon he made a surprising finding: Very long RNAs gradually disappear from the nucleus, where they are made, and shorter RNAs show up in the cytoplasm. The nucleotide composition of the large and the smaller molecules resemble each other and are characteristic of RNAs known to compose ribosomes, the protein-making factories of the cell. Together, the results indicated that mammalian cells pare down their original RNAs; they release several mature forms of ribosomal RNA (rRNA) from a giant precursor molecule. Darnell coined the term “RNA processing” to describe this phenomenon in a 1963 paper that reports this work.

When Darnell analyzed the largest and most fleeting RNA in the nucleus, he discovered that its composition does not resemble that of rRNA, but instead corresponds to that of total mammalian DNA and mRNA. He called this RNA heterogeneous nuclear RNA (hnRNA) and speculated that hnRNA is the nuclear precursor to mRNA just as pre-rRNA is the precursor to rRNA. Perhaps the mRNA lay in the middle or at the ends of the hnRNA molecule, awaiting liberation.

He and Mary Edmonds, of the University of Pittsburgh, independently found that some hnRNAs and almost all mRNAs carry a string of adenine nucleotides — a poly(A) — at one end. Furthermore, Darnell showed that poly(A) appears first in hnRNA and later in cytoplasmic mRNA, supporting the notion that the first molecule gives rise to the second one. Subsequently, scientists discovered a distinguishing chemical structure called a cap on the other end of both mRNA and hnRNA. Darnell found that many hnRNA molecules and all mRNA molecules carry one poly(A) tail and one cap. These observations posed an enigma: How could a long hnRNA with a tail and cap give rise to a short mRNA with the same characteristic tags at its ends? In retrospect, the answer is obvious, but at the time, the dogma that DNA sequence always corresponded exactly to mRNA sequence — and that genes were thus uninterrupted — forced scientists to surmount a tremendous intellectual barrier before stumbling upon the solution in 1977. Two teams — led by Phillip Sharp of MIT and Richard Roberts of Cold Spring Harbor Laboratory — vaulted this hurdle when they used electron microscopy to look at DNA bound to the mRNA it encodes. Large regions of the DNA looped out, and the groups proposed that internal spans of sequence — now called introns — were removed as hnRNA was transformed into mRNA. With this discovery, the field of mRNA splicing burst onto the scientific scene.

Knowing how mRNA was formed, Darnell next decided to back up a step and explore how cells regulate its production — or transcription — from DNA, and how they activate particular sets of genes to accomplish specialized physiological tasks. By the early 1980s, he had discovered that a liver cell could remain a liver cell only when it resided in its natural milieu. When he separated cells from each other, they stopped manufacturing liver-specific mRNAs within a few hours, although they continued to produce basic housekeeping mRNAs. Without constant signals from their normal habitat, liver cells lost the mRNA profile that helps give them their identity.

These observations made Darnell wonder how cues from outside the cell could spark specific gene activity. He suspected that he could analyze this issue by studying how proteins called interferons (IFNs) instigate human cells to guard themselves against viruses. These proteins — subdivided into groups called alpha, beta, and gamma — belong to a hormone family called cytokines that rev up antimicrobial defenses. Immediately after binding to the outside of a cell, IFNs spur the manufacture of proteins that quash viral duplication and render the infected cells more susceptible to attack by the immune system.

To get a handle on the cellular players that turn on genes in response to IFN, Darnell decided to work backwards, reasoning that the genes triggered by the cytokine would lead him to their molecular inducers. To find IFN-prodded genes, he identified mRNAs that accumulate in response to IFN-beta. His and another research group showed that the mRNA hike didn’t depend on new protein synthesis, implying that the cell possessed the IFN-responsive gene activator — or transcription factor — in a dormant state before stimulation.

After isolating a short stretch of DNA that lies next to IFN-alpha-induced genes, he sought cellular machinery that could sit down on this sequence and drive transcription of adjacent test genes. This strategy produced three nuclear factors that bound to that particular piece of DNA and not others; one of them appeared specifically in IFN-treated cells. This IFN-responsive transcription factor was what he sought; it hangs out in the cytoplasm, waiting for IFN to jolt it into action. Two thousand liters of IFN-treated cell cultures later, Darnell’s students and postdoctoral fellows had purified this factor, which consisted of four proteins. These were among the first purified proteins that respond to signals from outside the cell by binding to DNA and stimulating genes. Darnell subsequently named two of them STAT1 and STAT2, echoing the “STAT” call of a hospital loudspeaker — in part because they trigger genes quickly.

Once he had isolated the proteins that provoke the genes, he wondered what the cell uses to sense IFN outside the cell and goad the Stats into action. He soon discovered that when IFN attaches to its receptor on the surface of cells, STAT1 and STAT2 acquire a chemical group — phosphate — known to animate proteins. Other teams identified the enzymes that tack on these phosphates as Janus kinases, or JAKs, which cozy up to molecules that span the cell’s membrane. When IFN binds on the outside, these molecules prompt the JAKs to modify Stats. A new signaling system — the Jak-Stat pathway — was born, and provided the first detailed account of a pathway that leads from a tickle at the cell’s surface to changes in gene activity inside its nucleus. The findings elucidated how cells can dramatically switch physiological directions in response to environmental signals.

Since its discovery, the mammalian Stat family has expanded to seven members, and its relatives have popped up in a wide range of organisms, including worms, slime molds, and flies. IFN-alpha represents just one chemical prod for these transcription factors and the physiological consequences of Stat activation extend beyond the anti-viral response. STAT3, for example, participates in animal cell growth regulation, inflammation, resistance to cell death, and early embryonic development in response to a variety of stimuli — and drugs that act on this Stat might hold therapeutic value. Darnell showed that a hyperactive version of STAT3 spurs rampant cellular reproduction in culture and that an inhibitory version blocks this unrestrained growth. These results and others, together with the observation that more than 50 percent of human cancers contain constantly active STAT3, suggest that the protein normally prevents deranged cancer cells from committing suicide. Thus, a pharmaceutical agent that thwarts STAT3 might repel cancer. Other Stats, too, participate in medically relevant pathways. A drug that incites STAT5 (recombinant erythropoietin) is already on the market to combat anemia.

In addition to discovering the fields of RNA processing and Stat signaling, Darnell has co-written two textbooks — General Virology and Molecular Cell Biology—that have instructed countless students. He has personally influenced a tremendous number of trainees over the course of his career, having mentored more than two dozen PhD students and 100 postdoctoral fellows in his lab. These individuals include an exceptional number of creative scientists, including Sheldon Penman, David Baltimore, Jonathan Warner, Ronald Evans, Joseph Nevins, and Jeffrey Friedman.

Darnell has also played an indispensable role in building a strong independent junior faculty at The Rockefeller University. A long-held and cherished tradition of The Rockefeller University ordained that early career investigators should work in senior faculty members’ labs. In 1985, Darnell co-chaired a university committee charged with finding strong young candidates, and hiring them as independent scientists. The first five researchers refused the university’s offers because they didn’t believe that they’d be allowed the autonomy they desired. Now, owing in large part to Darnell’s effective leadership, Rockefeller competes for junior faculty with other top-notch institutions. The program has engaged several dozen young scientists in the last decade, 20 of whom have earned tenure. Scientists at other institutions have hailed this innovation, saying that it has greatly broadened the research fabric of the university.

For almost half a century, Darnell has had a major impact on science worldwide. He has uncovered major themes in RNA’s function as an informational molecule, and provided a molecular explanation for how the cell heeds signals from its environment. Throughout his career, he has devoted himself to nurturing young scientists, assuring his legacy through their achievements as well as his own.

by Evelyn Strauss

Key publications of Willem Kolff

Kolff, W.J., Berk, H.T.J., ter Welle, Z.M., van der Ley, A.J.W., van Dijk, E.C., and van Noordwijk, J. (1943). de Kunstmatige nier:een dialysator met groot oppervlak. Geneesk. Gids. 21, 3–12.

Kolff, W.J., Berk, H.T.J., ter Welle, Z.M., van der Ley, A.J.W., van Dijk, E.C., and van Noordwijk, J. (1942). de Kunstmatige nier:eendialysator met groot oppervlak. Ned. Tijdschr. V. Geeneskunde. 87, 1684–1687.

Kolff, W.J. and Terk, H.T.J. (1944). The artificial kidney: a dialyzer with a great area. Acta Med. Scand. 117, 121.

Kolff, W.J. and Watschinger, B. (1956). Further development of a coil kidney. J. Lab. Clin. Med. 47, 969–977.

Kolff, W.J., Effler, D.B., Groves, L.K., Peereboom, G., Moraca, P., Aoyama, S., and Sones, F.M. (1956). Disposable membrane oxygenator (heart-lung machine) and its use in experimental surgery. Elective Cardiac Arrest in open-heart surgery: report on three cases. Cleveland Clinic Quart. 23, 69–114.

Kolff, W.J. (1983). Artificial organs — forty years and beyond. Trans. ASAIO. 24, 6–24.

Key publications of Belding Scribner

Scribner, B.H., Caner, J.E.Z., Buri, R., and Quinton, W. (1960). The technique of continuous hemodialysis. Trans. ASAIO. 6, 88–103.

Quinton, W., Dillard, D., and Scribner, B.H. (1960). Cannulation of blood vessels for prolonged hemodialysis. Trans. ASAIO. 6, 104–113.

Scribner, B.H., Buri, R., Caner, J.E.Z., Hegstrom, R., and Burnell, J.M. (1960) The treatment of chronic uremia by means of intermittent hemodialysis: a preliminary report. Trans. ASAIO. 6, 114–122.

Pendras, J.P., Cole, J.J., Tu, W.H., and Scribner, B.H. (1961). Improved technique of continuous flow hemodialysis. Trans. ASAIO. 7, 27–36.

Murray, J.S., Tu, W.H., Albers, J.B., Burnell, J.M., and Scribner, B.H. (1962). A community hemodialysis center for the treatment of chronic uremia. Trans. ASAIO. 8, 315–319.

Eschback, J.W., Wilson, W.E., Peoples, R.W., Wakefield, A.W., Babb, A.L., and Scribner, B.H. (1966). Unattended overnight home hemodialysis. Trans. ASAIO. 12, 346–356.

Award presentation by Joseph Goldstein

In one of her short stories, the Danish writer Isak Dinesen poses a provocative question: “What is man, when you come to think upon him, but an ingenious machine for turning, with infinite artfulness, the red wine of Shiraz into urine?” Well, when you come to think upon it, this remarkable conversion is carried out by a real ingenious machine, the kidney — a truly remarkable organ. The kidney not only cleanses the blood of toxic products like the red wine of Shiraz, but it also regulates with extraordinary constancy the volume and composition of the body fluids that bathe all the tissues.

Claude Bernard, the great physiologist of the 19th century, pointed out that it is this constancy of the internal environment, orchestrated by the kidney, that allowed animals to achieve a free and independent life. Homer Smith, the great physiologist of the 20th century, had a more watered-down view of the kidney: “Bones can break, muscles can atrophy, glands can loaf, even the brain can go to sleep without immediate danger to survival. But should the kidneys fail — neither bone, muscle, gland, nor brain could carry on.” This is the ultimate kidney-centric view of the world.

When the kidneys fail, patients develop an intoxicating condition known as uremia, which produces nausea and vomiting, bleeding from the intestines, itching, convulsions, lethargy, and ultimately coma. Every year in the United States, tens of thousands of people suddenly develop acute failure of the kidney as a result of traumatic injuries from car accidents, severe burns, complicated pregnancies, and reactions to drugs. Every year, more than 90,000 people are also diagnosed with a chronic form of kidney failure caused by either long-standing hypertension or poorly controlled diabetes. This form of chronic kidney failure is called end-stage renal disease. Left untreated, both acute renal failure and end-stage renal disease produce uremia and death.

The development of an artificial kidney that could substitute for the body’s damaged kidneys constitutes one of the monumental life-saving advances in the history of modern medicine. Prosthetic devices for non-essential body parts, such as teeth, limbs, and even hair, have been available for centuries, but the artificial kidney is the only artificial device that can replace a vital organ on a permanent basis. The 2002 Lasker Award for Clinical Research celebrates the achievements of the two scientists who made all this possible — Willem Kolff and Belding Scribner.

Our story begins in 1938 at a small medical ward at the University of Groningen Hospital in the Netherlands. The physician in charge was Willem Kolff, who had just graduated from medical school. One of his first patients was a 22-year-old man in uremic coma. The young Dr. Kolff, then only 28 years old, watched helplessly for four days as the young man died in front of his eyes. He had no treatment to offer — if only he could find a way to remove the toxic metabolic wastes that accumulated in blood when the kidney failed. During the last day of the patient’s life, Kolff went to the university library and searched the literature for ways of purifying blood. To his delight and surprise, he found an article published 25 years earlier, in 1913, by a distinguished pharmacologist at Johns Hopkins University, named John Abel, who described a procedure for dialyzing the blood of dogs and rabbits. The blood was taken from the animal, passed through a series of porous colloid tubes that were bathed in salt solution, and then put back into the animal. Clotting of the blood was prevented with an anticoagulant called hirudin that Abel extracted from thousands of leeches obtained from Parisian barbers. In 1924–28, the German scientist Georg Haas first attempted hemodialysis on several humans with acute renal failure, but the duration of the procedure (30–60 minutes) was too short for any significant therapeutic effect.

Stimulated by Abel’s concept of hemodialysis, Kolff was determined to develop an artificial kidney that would save the lives of uremic patients. He rapidly overcame two of the technical obstacles inherent in the Abel technique: Heparin was substituted for the highly antigenic protein hirudin, and a thin cellophane membrane was used instead of a thick colloid tube. But then, Kolff faced an even more formidable obstacle: World War II had just broken out, and the Netherlands soon fell to Nazi Germany. Kolff was assigned to work in a 90-bed hospital in a small town called Kampen. Despite the difficult circumstances of Nazi-occupied Netherlands, Kolff miraculously cajoled an enamel manufacturing company to help him obtain scarce materials in order to construct the first artificial kidney. This machine, which came to be known as the “rotating-drum hemodialyzer,” consisted of 130 feet of cellophane tubing made from sausage casing, wrapped 30 times around a horizontal drum made out of aluminum strips. As the drum rotated through a bath of salt solution contained in an enamel tank, the patient’s blood was exposed to the dialysis bath, allowing rapid and efficient removal of the toxic wastes.

Between 1943 and 1944, Kolff treated 16 patients with acute kidney failure, but success was limited. The first unambiguous success came in 1945 with the 17th patient, a 67-year-old woman in uremic coma due to acute renal failure from Gram-negative sepsis. In one of the ironies of medical history, this patient was a Nazi sympathizer who had betrayed many of her Dutch countrymen to the Germans. After 11 hours of hemodialysis, the patient regained consciousness. According to Kolff, “I bent over and asked if she could hear me. She slowly opened her eyes and said, ‘I’m going to divorce my husband.'” Her kidneys began to produce urine, she recovered fully, and true to her word she divorced her husband, and lived seven more years before dying from another disease. Kolff had now achieved the first step in the conquest of kidney failure: The revolution of the drum had started a revolution that would ultimately improve the health of millions of people.

When World War II ended, Kolff donated all five of his artificial kidneys to hospitals in London, Poland, The Hague, Montreal, and Mt. Sinai Hospital here in New York City. This extraordinary act of generosity enabled physicians throughout the world to become familiar with the new technique of dialysis. He also provided blueprints of his rotating-drum hemodialyzer to George Thorn at the Peter Bent Brigham Hospital in Boston. This led to the manufacture of the Kolff-Brigham kidney, which was an improved stainless steel version of the original. The Kolff-Brigham kidney made it possible for John Merrill to establish the first major program for hemodialysis in the United States and paved the way for the first kidney transplantation by Joe Murray in 1954. Kolff-Brigham kidneys were also used during the Korean War to dialyze American soldiers who suffered massive wounds and posttraumatic renal failure.

After inventing the artificial kidney, Kolff went on to become the world’s premier biomedical engineer — inventing the pump oxygenator for open heart surgery in 1955, the aortic balloon pump for treatment of cardiogenic shock in 1961, and the artificial heart that prolonged the life of Barney Clark for 112 days in 1982. As he approaches his 92nd birthday, Kolff refuses to rust on his laurels; he is as passionate as ever in his inventive quest for new body parts, now pursuing the artificial eye and the artificial ear.

The Kolff kidney solved the problem of acute renal failure, but what about the hundreds of thousands of patients with chronic end-stage renal disease for whom prolongation of life requires repeated dialysis three times a week forever? In the late 1950s, the conventional wisdom among kidney experts was that chronic intermittent dialysis would never be possible because of two insurmountable problems — one technical and one psychological. The technical problem was one of circulatory access: Every time a patient was hooked up to a dialysis machine veins and arteries were damaged, and after six or seven treatments, physicians would run out of places to connect the machine. The psychological problem stemmed from the widely held mystical belief that a cellophane dialyzer outside the body could never permanently replace the complex functions of a normal organ. After all, according to the experts, the kidney was a sacred organ. Above and beyond its excretory function, it produces three essential hormones — erythropoietin for forming red blood cells, renin for maintaining blood volume and blood pressure, and hydroxylated vitamin D for preventing breakdown of the bones.

In 1960, the impossible suddenly became possible. The psychological and technical barriers to chronic dialysis came crashing down through the research of Belding Scribner, a young professor of medicine at the University of Washington in Seattle. Like Kolff, Scribner was a dedicated physician whose imagination was triggered by a patient who was slowly dying of end-stage renal disease. After a sleepless night agonizing over the fate of his patient, Scribner got out of bed at 4:00 a.m., and in a sudden flash jotted down an idea about how to solve the problem of circulatory access. His idea was elegant in its simplicity: sew plastic tubes into an artery and a vein in the patient’s arm for connection to the artificial kidney. When the dialysis treatment was over, keep the access to the circulation open by hooking the two tubes together outside the patient’s body via a small U-shaped device, made of Teflon. This U-shaped Teflon device, which came to be known as the Scribner shunt, served as a permanently installed extension of the patient’s own circulatory system, shunting the blood from the tube in the artery back to the tube in the vein. Whenever the patient needed to be dialyzed again, no new incisions in the blood vessels had to be made. The shunt was simply disconnected from the tubes in the patient’s arm, and the patient was hooked up again to the machine.

One of the key factors contributing to success of the Scribner shunt was the use of the then-new material Teflon, whose nonsticky properties prevented clotting of the blood. Although it has been replaced today by improved methods of circulatory access, the Scribner shunt was the technical breakthrough that transformed the outlook of patients with end-stage renal disease from a sentence of death to a prolongation of life. The first patient to receive a Scribner shunt was dialyzed repeatedly for 11 years, and the fifth patient was dialyzed for 36 years, undergoing 5700 cycles of hemodialysis, before he died several years ago.

In 1962, Scribner established the world’s first outpatient dialysis center, now known as the Northwest Kidney Center. Almost immediately, the demand to treat patients vastly exceeded the capacity of the original six dialysis machines. To make matters worse, in 1962, insurance companies and Medicare did not cover the costs of chronic dialysis, which was $10,000 per year in 1960 dollars. Dying patients were clamoring to be dialyzed. Who goes on the machine first? Scribner suddenly found himself in one heck of a pickle. His solution to the allocation problem was novel and clever. The decision to choose who should live or die would be made, not by Scribner himself, but by an anonymous committee of citizens, appointed by the local Seattle medical society, that included five lay community leaders from various walks of life and two physicians outside of the kidney field. The creation of this bioethics committee — the first of its kind — was highly controversial at the time, but in retrospect it changed the thinking about accessibility of health care in the United States.

In another innovation, Scribner ushered in the era of home dialysis by developing a miniature portable dialysis machine with fail-safe devices that could be run by family members. Today, 40 years later, nearly 300,000 patients in the United States and 1.5 million worldwide are undergoing chronic dialysis either at home or at dialysis centers. The technology of chronic dialysis has become so sophisticated that thousands of patients with end-stage renal disease take holiday cruises to exotic places anywhere in the world. Next week, for example, the MS Rotterdam leaves New York City for a two-week “Dialysis at Sea Cruise” to Bermuda and Barcelona.

The contributions of Willem Kolff and Belding Scribner revolutionized the treatment of kidney disease, saving and prolonging the useful lives of millions of people. To paraphrase Isak Dinesen, “What is the artificial kidney, when you come to think upon it, but an ingenious machine of Kolffian cellophane and Scribnerian Teflon for turning, with infinite artfulness, death into life?”

Interview with Willem Kolff and Belding Scribner