The Brown family at the Grand Tetons (2019). Clockwise from left, Christine, Kevin, Keagan, Connor, and Kellen.
But Christine Brown knew none of this when the hospital called saying that standard newborn screening of her son Connor had come back positive for PKU. It was urgent that they visit a special metabolic clinic the next day, which was about a three-hour drive away.
“I was told not to go on the Internet,” Christine recalls, “So when somebody tells you not to go on the Internet, what do you do? Even back in 2005, right.” What she saw were the worst examples of retardation, which was a common outcome from PKU before newborn screening became routine. “We were just in complete shell shock, our whole world just kind of shattered and went into a tail spin.”
“I remember feeding him the night before our clinic visit and almost feeling like I was feeding him poison because I knew that breast milk must have protein in it,” she says.
“Some of my first memories are of asking, ‘Mommy, can I eat this? There were yes foods and no foods.'"
Over the next few days the dedicated staff of the metabolic clinic at the Waisman Center at the University of Wisconsin Madison began to walk she and husband Kevin back from that nightmare. They learned that a simple blood test to screen newborns had been developed in the early 1960s to detect PKU and that the condition could be managed with stringent food restrictions and vigilant monitoring of Phe levels.
Everything in Your Mouth Counts
PKU can be successfully managed with a severely restricted diet. That simple statement is factually true, but practically impossible to follow, as it requires slashing protein consumption by about 90 percent. To compensate for the missing protein, several times a day PKU patients take a medical formula – commonly referred to simply as formula – containing forms of proteins that are digestible to their bodies. Several manufacturers now add vitamins and minerals and offer a variety of formats and tastes to make it more consumer friendly, but that wasn't always the case.
“When I was a kid, it tasted horrible, was the consistency of house paint. I didn't think about it, I just drank it. I didn't like it but you get used to it after a while,” recalls Jeff Wolf, the twang of Appalachia still strong in his voice. Now age 50, he grew up in Ashland, Kentucky and was part of the first wave of persons with PKU who were identified at birth as newborn screening was rolled out across the US. He says the options of taste and consistency have improved tremendously over the years.
Some people with PKU are restricted to as little as 8 grams of protein a day from food. That's a handful of almonds or a single hard-boiled egg; a skimpy 4-ounce hamburger and slice of cheese adds up to half of their weekly protein ration. Anything above that daily allowance is more than the body can handle and toxic levels of Phe begin to accumulate in the brain.
“Some of my first memories are of asking, ‘Mommy, can I eat this? There were yes foods and no foods,’” recalls Les Clark. He has never eaten a hamburger, steak, or ribs, practically a sacrilege for someone raised in Stanton, a small town in northeastern Nebraska, a state where the number of cattle and hogs are several-fold those of people.
His grandmother learned how to make low protein bread, but it looked and tasted different. His mom struggled making birthday cakes. “I learned some bad words at a very young age” as mom struggled applying icing that would pull the cake apart or a slice would collapse into a heap of crumbs, Les recalls.
Les Clark with a birthday cake.
Courtesy Clark
Controlling the diet “is not so bad when you are a baby” because that's all you know, says Jerry Vockley, Director of the Center for Rare Disease Therapy at Children's Hospital of Pittsburgh. “But after a while, as you get older and you start tasting other things and you say, Well, gee, this stuff tastes way better than what you're giving me. What's the deal? It becomes harder to maintain the diet.”
First is the lure of forbidden foods as children venture into the community away from the watchful eyes of parents. The support system weakens further when they leave home for college or work. “Pizza was mighty tasty,” Wolf' says of his first slice.
Vockley estimates that about 90 percent of adults with PKU are off of treatment. Moving might mean finding a new metabolic clinic that treats PKU. A lapse in insurance coverage can be a factor. Finally there is plain fatigue from multiple daily dosing of barely tolerable formula, monitoring protein intake, and simply being different in terms of food restrictions. Most people want to fit in and not be defined by their medical condition.
Jeff Wolf was one of those who dropped out in his twenties and thirties. He stopped going to clinic, monitoring his Phe levels, and counting protein. But the earlier experience of living with PKU never completely left the back of his mind; he listened to his body whenever eating too much protein left him with the “fuzzy brain" of a protein hangover. About a decade ago he reconnected with a metabolic clinic, began taking formula and watching his protein intake. He still may go over his allotment for a single day but he tries to compensate on subsequent days so that his Phe levels come back into balance.
Jeff Wolf on a boat.
Courtesy Wolf
One of the trickiest parts of trying to manage phenylalanine intake is the artificial sweetener aspartame. The chemical is ubiquitous in diet and lite foods and drinks. Gum too, you don't even have to swallow to receive a toxic dose of Phe. Most PKUers say it is easier to simply avoid these products entirely rather than try to count their Phe content.
Treatments
Most rare diseases have no treatment. There are two drugs for PKU that provide some benefit to some portion of patients but those drugs often have their own burdens.
KUVAN® (sapropterin dihydrochloride) is a pill or powder that helps correct a protein folding error so that food proteins can be digested. It is approved for most types of PKU in adults and children one month and older, and often is used along with a protein-restricted diet.
“The problem is that it doesn't work for every [patient's genetic] mutation, and there are hundreds of mutations that have been identified with PKU. Two to three percent of patients will have a very dramatic response and if you're one of those small number of patients, it's great,” says Vockley. “If you have one of the other mutation, chances are pretty good you still are going to end up on a restricted diet.”
PALYNZIQ® (pegvaliase-pqpz) “has the potential to lower the Phe to normal levels, it's a real breakthrough in the field,” says Vockley. “But is a very hard drug to use. Most folks have to take either one or two 2ml injections a day of something that is basically a gel, and some individuals have to take three.”
Many PKUers have reactions at the site of the injection and some develop anaphylaxis, a severe potentially life-threatening allergic reaction that can happen within seconds and can occur at any time, even after long term use. Many patients using Palynziq carry an EpiPen, a self-injection devise containing a form of adrenaline that can reverse some of the symptoms of anaphylaxis.
Then there is the cost. With the Kuvan dosing for an adult, “you're talking between $100,000 and $200,000 a year. And Palynziq is three times that,” says Vockley. Insurance coverage through a private plan or a state program is essential. Some state programs provide generous coverage while others are skimpy. Most large insurance company plans cover the drugs, sometimes with significant copays, but companies that are self-insured are under no legal obligation to provide coverage.
Les Clark found that out the hard way when the company he worked for was sold. The new owner was self-insured and declined to continue covering his drugs. Almost immediately he was out of pocket an additional $1500 a month for formula, and that was with a substantial discount through the manufacturer's patient support program. He says, “If you don't have an insurance policy that will cover the formula, it's completely unaffordable.” He quickly began to look for a new job.
Hope
It's easy to see why PKUers are eager for advances that will make managing their condition more effect, easier, and perhaps more affordable. Synlogic's efforts have drawn their attention and raised hopes.
Just before Thanksgiving Jerry Vockley presented the latest data to a metabolism conference meeting in Australia. There were only 8 patients in this group of a phase 2 trial using the original version of the company's lead E. coli product, SYNB1618, but they were intensely studied. Each was given the probiotic and then a challenge meal. Vockley saw a 40% reduction in Phe absorption and later a 20% reduction in mean fasting Phe levels in the blood. The product was easy to use and tolerate.
The company also presented early results for SYNB1934, a follow on version that further genetically tweaked the E. coli to roughly double the capacity to chop up the target proteins. Synlogic is recruiting patients for studies to determine the best dosing, which they are planning for next year.
“It's an exciting approach,” says Lex Cowsert, Director of Research Development at the National PKU Alliance, a nonprofit that supports the patient, family, and research communities involved with PKU. “Every patient is different, every patient has a different tolerance for the type of therapy that they are willing to pursue,” and if it pans out, it will be a welcome addition, either alone or in combination with other approaches, to living with PKU.
Author's Note: Reporting this story was made possible by generous support from the National Press Foundation and the Fondation Ipsen. Thanks to the people who so generously shared their time and stories in speaking with me.
Ordinary people are living better with chronic conditions thanks to a recent explosion of developments in medical implants.
The demand for transplantable organs dwarfs their availability. There are currently over 100,000 people on the transplant waiting list in the U.S., compared to 40,000 transplants completed in 2021. But even this doesn’t reflect the number of people in dire straits who don’t qualify for a transplant because of things like frailty, smoking status and their low odds of surviving the surgery.
My journey to becoming a cyborg came about because of a lifelong medical condition characterized by pathologically low motility of the digestive system, called gastroparesis. Ever since I was in my teens, I’ve had chronic problems with severe nausea. Flareups can be totally incapacitating and last anywhere from hours to months, interspersed with periods of relief. The cycle is totally unpredictable, and for decades my condition went both un- and misdiagnosed by doctors who were not even aware that the condition existed. Over the years I was labeled with whatever fashionable but totally inappropriate medical label existed at the time, and not infrequently, hypochondria.
Living with the gastric pacer is easy. In fact, most of the time, I don’t even know it’s there.
One of the biggest turning points in my life came when a surgeon at the George Washington University Hospital, Dr. Frederick Brody, ordered a gastric emptying test that revealed gastroparesis. This was in 2009, and an implantable device, called a gastric pacer, had been approved by the FDA for compassionate use, meaning that no other treatments were available. The small device is like a pacemaker that’s implanted beneath the skin of the abdomen and is attached to the stomach through electrodes that carry electrical pulses that stimulate the stomach, making it contract as it’s supposed to.
Dr. Brody implanted the electrical wires and the device, and, once my stomach started to respond to the pulses, I got the most significant nausea relief I’d had in decades of futile treatments. It sounds cliché to say that my debt to Dr. Brody is immeasurable, but the pacer has given me more years of relative normalcy than I previously could have dreamed of.
I should emphasize that the pacer is not a cure. I still take a lot of medicine and have to maintain a soft, primarily vegetarian diet, and the condition has progressed with age. I have ups and downs, and can still have periods of severe illness, but there’s no doubt I would be far worse off without the electrical stimulation provided by the pacer.
Living with the gastric pacer is easy. In fact, most of the time, I don’t even know it’s there. It entails periodic visits with a surgeon who can adjust the strength of the electrical pulses using a wireless device, so when symptoms are worse, he or she can amp up the juice. If the pulses are too strong, they can cause annoying contractions in the abdominal muscles, but this is easily fixed with a simple wireless adjustment. The battery runs down after a few years, and when this happens the whole device has to be replaced in what is considered minor surgery.
Such devices could fill gaps in treating other organ failures. By far most of the people on transplant waiting lists are waiting for kidneys. Despite the fact that live donations are possible, there’s still a dire shortage of organs. A bright spot on the horizon is The Kidney Project, a program spearheaded by bioengineer Shuvo Roy at the University of California, San Francisco, which is developing a fully implantable artificial kidney. The device combines living cells with artificial materials and relies not on a battery, but on the patient’s own blood pressure to keep it functioning.
Several years into this project, a prototype of the kidney, about the size of a smart phone, has been successfully tested in pigs. The device seems to provide many of the functions of a biological kidney (unlike dialysis, which replaces only one main function) and reliably produces urine. One of its most critical components is a special artificial membrane, called a hemofilter, that filters out toxins and waste products from the blood without leaking important molecules like albumin. Since it allows for total mobility, the artificial kidney will provide patients with a higher quality of life than those on dialysis, and is in some important ways, even better than a biological transplant.
The beauty of the device is that, even though it contains kidney cells sourced, as of now, from cadavers or pigs, the cells are treated so that they can’t be rejected and the device doesn’t require the highly problematic immunosuppressant drugs a biological organ requires. “Anti-rejection drugs,” says Roy, “make you susceptible to all kinds of infections and damage the transplanted organ, causing steady deterioration. Eventually they kill the kidney. A biological transplant has about a 10-year limit,” after which the kidney fails and the body rejects it.
Eventually, says Roy, the cells used in the artificial kidney will be sourced from the patient himself, the ultimate genetic match. The patient’s adult stem cells can be used to produce some or all of the 25 to 30 specialized cells of a biological kidney that provide all the functions of a natural organ. People formerly on dialysis could drastically improve their functionality and quality of life without being tethered to a machine for hours at a time, three days a week.
As exciting as this project is, it suffers from a common theme in early biomedical research—keeping a steady stream of funding that will move the project from the lab, into human clinical trials and eventually to the bedside. “It’s the issue,” says Roy. “Potential investors want to see more data indicating that it works, but you need funding to create data. It’s a Catch-22 that puts you in a kind of no-man’s land of funding.” The constant pursuit of funding introduces a variable that makes it hard to predict when the kidney will make it to market, despite the enormous need for such a technology.
Another critical variable is if and when insurance companies will decide to cover transplants with the artificial kidney, so that it becomes affordable for the average person. But Roy thinks that this hurdle, too, will be crossed. Insurance companies stand to save a great deal of money compared to what they ordinarily spend on transplant patients. The cost of yearly maintenance will be a fraction of that associated with the tens of thousands of dollars for immunosuppressant drugs and the attendant complications associated with a biological transplant.
One estimate that the multidisciplinary team of researchers involved with The Kidney Project are still trying to establish is how long the artificial kidney will last once transplanted into the body. Animal trials so far have been looking at how the kidney works for 30 days, and will soon extend that study to 90 days. Additional studies will extend much farther into the future, but first the kidneys have to be implanted into people who can be followed over many years to answer this question. But unlike the gastric pacer and other implants, there won’t be a need for periodic surgeries to replace a depleted battery, and the stark improvements in quality of life compared to dialysis add a special dimension to the value of whatever time the kidney lasts.
Another life-saving implant could address a major scourge of the modern world—heart disease. Despite significant advances in recent decades, including the cardiac implants mentioned above, cardiovascular disease still causes one in three deaths across the world. One of the most promising developments in recent years is the Total Artificial Heart, a pneumatically driven device that can be used in patients with biventricular heart failure, affecting both sides of the heart, when a biological organ is not available.
The TAH is implanted in the chest cavity and has two tubes that snake down the body, come out through the abdomen and attach to a 13.5-pound external driver that the patient carries around in a backpack. It was first developed as a bridge to transplant, a temporary alternative while the patient waited for a biological heart to replace it. However, SynCardia Systems, LLC, the Tucson-based company that makes it, is now investigating whether the heart can be used on a long-term basis.
There’s good reason to think that this will be the case. I spoke with Daniel Teo, one of the board members of SynCardia, who said that so far, one patient lived with the TAH for six years and nine months, before he died of other causes. Another patient, still alive, has lived with the device for over five years and another one has lived with it for over four years. About 2,000 of these transplants have been done in patients waiting for biological hearts so far, and most have lived mobile, even active lives. One TAH recipient hiked for 600 miles, and another ran the 4.2-mile Pat Tillman Run, both while on the artificial heart. This is a far cry from their activities before surgery, while living with advanced heart failure.
Randy Shepard, a recipient of the Total Artificial Heart, teaches archery to his son.
Randy Shepard
If removing and replacing one’s biological heart with a synthetic device sounds scary, it is. But then so is replacing one’s heart with biological one. “The TAH is very emotionally loaded for most people,” says Teo. “People sometimes hold back because of philosophical, existential questions and other nonmedical reasons.” He also cites cultural reasons why some people could be hesitant to accept an artificial heart, saying that some religions could frown upon it, just as they forbid other medical interventions.
The first TAHs that were approved were 70 cubic centimeters in size and fit into the chest cavities of men and larger women, but there’s now a smaller, 50 cc size meant for women and adolescents. The FDA first cleared the 70 cc heart as a bridge to transplant in 2004, and the 50 cc model received approval in 2014. SynCardia’s focus now is on seeking FDA approval to use the heart on a long-term basis. There are other improvements in the works.
One issue being refined deals with the external driver that holds the pneumatic device for moving the blood through a patient’s body. The two tubes connecting the driver to the heart entail openings in the skin that could get infected, and carrying the backpack is less than ideal. The driver also makes an audible sound that some people find disturbing. The next generation TAH will be quieter and involve wearing a smaller, lighter device on a belt rather than carrying the backpack. SynCardia is also working toward a fully implantable heart that wouldn’t require any external components and would contain an energy source that can be recharged wirelessly.
Teo says the jury is out as to whether artificial hearts will ever obviate the need for biological organs, but the world’s number one killer isn’t going away any time soon. “The heart is one of the strongest organs,” he says, “but it’s not made to last forever. If you live long enough, the heart will eventually fail, and heart failure leads to the failure of other organs like the kidney, the lungs and the liver.” As long as this remains the case and as long as the current direction of research continues, artificial organs are likely to play an ever larger part of our everyday lives.
Oh, wait. Maybe we cyborgs will take over the world after all.
