People With This Rare Disease Can Barely Eat Protein. Biotechnology May Change That.
Imagine that the protein in bread, eggs, steak, even beans is not the foundation for a healthy diet, but a poison to your brain. That is the reality for people living with Phenylketonuria, or PKU. This cluster of rare genetic variations affects the ability to digest phenylalanine (Phe), one of the chemical building blocks of protein. The toxins can build up in the brain causing severe mental retardation.
Can a probiotic help digest the troublesome proteins before they can enter the bloodstream and travel to the brain? A Boston area biotech start up, Synlogic, believes it can. Their starting point is an E. coli bacterium that has been used as a probiotic for more than a century. The company then screened thousands of gene variants to identify ones that produced enzymes most efficient at slicing and dicing the target proteins and optimized them further through directed evolution. The results have been encouraging.
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.
The future of non-hormonal birth control: Antibodies can stop sperm in their tracks
Unwanted pregnancy can now be added to the list of preventions that antibodies may be fighting in the near future. For decades, really since the 1980s, engineered monoclonal antibodies have been knocking out invading germs — preventing everything from cancer to COVID. Sperm, which have some of the same properties as germs, may be next.
Not only is there an unmet need on the market for alternatives to hormonal contraceptives, the genesis for the original research was personal for the then 22-year-old scientist who led it. Her findings were used to launch a company that could, within the decade, bring a new kind of contraceptive to the marketplace.
The genesis
It’s Suruchi Shrestha’s research — published in Science Translational Medicine in August 2021 and conducted as part of her dissertation while she was a graduate student at the University of North Carolina at Chapel Hill — that could change the future of contraception for many women worldwide. According to a Guttmacher Institute report, in the U.S. alone, there were 46 million sexually active women of reproductive age (15–49) who did not want to get pregnant in 2018. With the overturning of Roe v. Wade last year, Shrestha’s research could, indeed, be life changing for millions of American women and their families.
Now a scientist with NextVivo, Shrestha is not directly involved in the development of the contraceptive that is based on her research. But, back in 2016 when she was going through her own problems with hormonal contraceptives, she “was very personally invested” in her research project, Shrestha says. She was coping with a long list of negative effects from an implanted hormonal IUD. According to the Mayo Clinic, those can include severe pelvic pain, headaches, acute acne, breast tenderness, irregular bleeding and mood swings. After a year, she had the IUD removed, but it took another full year before all the side effects finally subsided; she also watched her sister suffer the “same tribulations” after trying a hormonal IUD, she says.
For contraceptive use either daily or monthly, Shrestha says, “You want the antibody to be very potent and also cheap.” That was her goal when she launched her study.
Shrestha unshelved antibody research that had been sitting idle for decades. It was in the late 80s that scientists in Japan first tried to develop anti-sperm antibodies for contraceptive use. But, 35 years ago, “Antibody production had not been streamlined as it is now, so antibodies were very expensive,” Shrestha explains. So, they shifted away from birth control, opting to focus on developing antibodies for vaccines.
Over the course of the last three decades, different teams of researchers have been working to make the antibody more effective, bringing the cost down, though it’s still expensive, according to Shrestha. For contraceptive use either daily or monthly, she says, “You want the antibody to be very potent and also cheap.” That was her goal when she launched her study.
The problem
The problem with contraceptives for women, Shrestha says, is that all but a few of them are hormone-based or have other negative side effects. In fact, some studies and reports show that millions of women risk unintended pregnancy because of medical contraindications with hormone-based contraceptives or to avoid the risks and side effects. While there are about a dozen contraceptive choices for women, there are two for men: the condom, considered 98% effective if used correctly, and vasectomy, 99% effective. Neither of these choices are hormone-based.
On the non-hormonal side for women, there is the diaphragm which is considered only 87 percent effective. It works better with the addition of spermicides — Nonoxynol-9, or N-9 — however, they are detergents; they not only kill the sperm, they also erode the vaginal epithelium. And, there’s the non-hormonal IUD which is 99% effective. However, the IUD needs to be inserted by a medical professional, and it has a number of negative side effects, including painful cramping at a higher frequency and extremely heavy or “abnormal” and unpredictable menstrual flows.
The hormonal version of the IUD, also considered 99% effective, is the one Shrestha used which caused her two years of pain. Of course, there’s the pill, which needs to be taken daily, and the birth control ring which is worn 24/7. Both cause side effects similar to the other hormonal contraceptives on the market. The ring is considered 93% effective mostly because of user error; the pill is considered 99% effective if taken correctly.
“That’s where we saw this opening or gap for women. We want a safe, non-hormonal contraceptive,” Shrestha says. Compounding the lack of good choices, is poor access to quality sex education and family planning information, according to the non-profit Urban Institute. A focus group survey suggested that the sex education women received “often lacked substance, leaving them feeling unprepared to make smart decisions about their sexual health and safety,” wrote the authors of the Urban Institute report. In fact, nearly half (45%, or 2.8 million) of the pregnancies that occur each year in the US are unintended, reports the Guttmacher Institute. Globally the numbers are similar. According to a new report by the United Nations, each year there are 121 million unintended pregnancies, worldwide.
The science
The early work on antibodies as a contraceptive had been inspired by women with infertility. It turns out that 9 to 12 percent of women who are treated for infertility have antibodies that develop naturally and work against sperm. Shrestha was encouraged that the antibodies were specific to the target — sperm — and therefore “very safe to use in women.” She aimed to make the antibodies more stable, more effective and less expensive so they could be more easily manufactured.
Since antibodies tend to stick to things that you tell them to stick to, the idea was, basically, to engineer antibodies to stick to sperm so they would stop swimming. Shrestha and her colleagues took the binding arm of an antibody that they’d isolated from an infertile woman. Then, targeting a unique surface antigen present on human sperm, they engineered a panel of antibodies with as many as six to 10 binding arms — “almost like tongs with prongs on the tongs, that bind the sperm,” explains Shrestha. “We decided to add those grabbers on top of it, behind it. So it went from having two prongs to almost 10. And the whole goal was to have so many arms binding the sperm that it clumps it” into a “dollop,” explains Shrestha, who earned a patent on her research.
Suruchi Shrestha works in the lab with a colleague. In 2016, her research on antibodies for birth control was inspired by her own experience with side effects from an implanted hormonal IUD.
UNC - Chapel Hill
The sperm stays right where it met the antibody, never reaching the egg for fertilization. Eventually, and naturally, “Our vaginal system will just flush it out,” Shrestha explains.
“She showed in her early studies that [she] definitely got the sperm immotile, so they didn't move. And that was a really promising start,” says Jasmine Edelstein, a scientist with an expertise in antibody engineering who was not involved in this research. Shrestha’s team at UNC reproduced the effect in the sheep, notes Edelstein, who works at the startup Be Biopharma. In fact, Shrestha’s anti-sperm antibodies that caused the sperm to agglutinate, or clump together, were 99.9% effective when delivered topically to the sheep’s reproductive tracts.
The future
Going forward, Shrestha thinks the ideal approach would be delivering the antibodies through a vaginal ring. “We want to use it at the source of the spark,” Shrestha says, as opposed to less direct methods, such as taking a pill. The ring would dissolve after one month, she explains, “and then you get another one.”
Engineered to have a long shelf life, the anti-sperm antibody ring could be purchased without a prescription, and women could insert it themselves, without a doctor. “That's our hope, so that it is accessible,” Shrestha says. “Anybody can just go and grab it and not worry about pregnancy or unintended pregnancy.”
Her patented research has been licensed by several biotech companies for clinical trials. A number of Shrestha’s co-authors, including her lab advisor, Sam Lai, have launched a company, Mucommune, to continue developing the contraceptives based on these antibodies.
And, results from a small clinical trial run by researchers at Boston University Chobanian & Avedisian School of Medicine show that a dissolvable vaginal film with antibodies was safe when tested on healthy women of reproductive age. That same group of researchers last year received a $7.2 million grant from the National Institute of Health for further research on monoclonal antibody-based contraceptives, which have also been shown to block transmission of viruses, like HIV.
“As the costs come down, this becomes a more realistic option potentially for women,” says Edelstein. “The impact could be tremendous.”
This article was first published by Leaps.org in December, 2022. It has been lightly edited with updates for timeliness.
Researchers probe extreme gene therapy for severe alcoholism
Story by Freethink
A single shot — a gene therapy injected into the brain — dramatically reduced alcohol consumption in monkeys that previously drank heavily. If the therapy is safe and effective in people, it might one day be a permanent treatment for alcoholism for people with no other options.
The challenge: Alcohol use disorder (AUD) means a person has trouble controlling their alcohol consumption, even when it is negatively affecting their life, job, or health.
In the U.S., more than 10 percent of people over the age of 12 are estimated to have AUD, and while medications, counseling, or sheer willpower can help some stop drinking, staying sober can be a huge struggle — an estimated 40-60 percent of people relapse at least once.
A team of U.S. researchers suspected that an in-development gene therapy for Parkinson’s disease might work as a dopamine-replenishing treatment for alcoholism, too.
According to the CDC, more than 140,000 Americans are dying each year from alcohol-related causes, and the rate of deaths has been rising for years, especially during the pandemic.
The idea: For occasional drinkers, alcohol causes the brain to release more dopamine, a chemical that makes you feel good. Chronic alcohol use, however, causes the brain to produce, and process, less dopamine, and this persistent dopamine deficit has been linked to alcohol relapse.
There is currently no way to reverse the changes in the brain brought about by AUD, but a team of U.S. researchers suspected that an in-development gene therapy for Parkinson’s disease might work as a dopamine-replenishing treatment for alcoholism, too.
To find out, they tested it in heavy-drinking monkeys — and the animals’ alcohol consumption dropped by 90% over the course of a year.
How it works: The treatment centers on the protein GDNF (“glial cell line-derived neurotrophic factor”), which supports the survival of certain neurons, including ones linked to dopamine.
For the new study, a harmless virus was used to deliver the gene that codes for GDNF into the brains of four monkeys that, when they had the option, drank heavily — the amount of ethanol-infused water they consumed would be equivalent to a person having nine drinks per day.
“We targeted the cell bodies that produce dopamine with this gene to increase dopamine synthesis, thereby replenishing or restoring what chronic drinking has taken away,” said co-lead researcher Kathleen Grant.
To serve as controls, another four heavy-drinking monkeys underwent the same procedure, but with a saline solution delivered instead of the gene therapy.
The results: All of the monkeys had their access to alcohol removed for two months following the surgery. When it was then reintroduced for four weeks, the heavy drinkers consumed 50 percent less compared to the control group.
When the researchers examined the monkeys’ brains at the end of the study, they were able to confirm that dopamine levels had been replenished in the treated animals, but remained low in the controls.
The researchers then took the alcohol away for another four weeks, before giving it back for four. They repeated this cycle for a year, and by the end of it, the treated monkeys’ consumption had fallen by more than 90 percent compared to the controls.
“Drinking went down to almost zero,” said Grant. “For months on end, these animals would choose to drink water and just avoid drinking alcohol altogether. They decreased their drinking to the point that it was so low we didn’t record a blood-alcohol level.”
When the researchers examined the monkeys’ brains at the end of the study, they were able to confirm that dopamine levels had been replenished in the treated animals, but remained low in the controls.
Looking ahead: Dopamine is involved in a lot more than addiction, so more research is needed to not only see if the results translate to people but whether the gene therapy leads to any unwanted changes to mood or behavior.
Because the therapy requires invasive brain surgery and is likely irreversible, it’s unlikely to ever become a common treatment for alcoholism — but it could one day be the only thing standing between people with severe AUD and death.
“[The treatment] would be most appropriate for people who have already shown that all our normal therapeutic approaches do not work for them,” said Grant. “They are likely to create severe harm or kill themselves or others due to their drinking.”
This article originally appeared on Freethink, home of the brightest minds and biggest ideas of all time.