Scientists Are Growing an Edible Cholera Vaccine in Rice
The world's attention has been focused on the coronavirus crisis but Yemen, Bangladesh and many others countries in Asia and Africa are also in the grips of another pandemic: cholera. The current cholera pandemic first emerged in the 1970s and has devastated many communities in low-income countries. Each year, cholera is responsible for an estimated 1.3 million to 4 million cases and 21,000 to 143,000 deaths worldwide.
Immunologist Hiroshi Kiyono and his team at the University of Tokyo hope they can be part of the solution: They're making a cholera vaccine out of rice.
"It is much less expensive than a traditional vaccine, by a long shot."
Cholera is caused by eating food or drinking water that's contaminated by the feces of a person infected with the cholera bacteria, Vibrio cholerae. The bacteria produces the cholera toxin in the intestines, leading to vomiting, diarrhea and severe dehydration. Cholera can kill within hours of infection if it if's not treated quickly.
Current cholera vaccines are mainly oral. The most common oral are given in two doses and are made out of animal or insect cells that are infected with killed or weakened cholera bacteria. Dukoral also includes cells infected with CTB, a non-harmful part of the cholera toxin. Scientists grow cells containing the cholera bacteria and the CTB in bioreactors, large tanks in which conditions can be carefully controlled.
These cholera vaccines offer moderate protection but it wears off relatively quickly. Cold storage can also be an issue. The most common oral vaccines can be stored at room temperature but only for 14 days.
"Current vaccines confer around 60% efficacy over five years post-vaccination," says Lucy Breakwell, who leads the U.S. Centers for Disease Control and Prevention's cholera work within Global Immunization Division. Given the limited protection, refrigeration issue, and the fact that current oral vaccines require two disease, delivery of cholera vaccines in a campaign or emergency setting can be challenging. "There is a need to develop and test new vaccines to improve public health response to cholera outbreaks."
A New Kind of Vaccine
Kiyono and scientists at Tokyo University are creating a new, plant-based cholera vaccine dubbed MucoRice-CTB. The researchers genetically modify rice so that it contains CTB, a non-harmful part of the cholera toxin. The rice is crushed into a powder, mixed with saline solution and then drunk. The digestive tract is lined with mucosal membranes which contain the mucosal immune system. The mucosal immune system gets trained to recognize the cholera toxin as the rice passes through the intestines.
The cholera toxin has two main parts: the A subunit, which is harmful, and the B subunit, also known as CTB, which is nontoxic but allows the cholera bacteria to attach to gut cells. By inducing CTB-specific antibodies, "we might be able to block the binding of the vaccine toxin to gut cells, leading to the prevention of the toxin causing diarrhea," Kiyono says.
Kiyono studies the immune responses that occur at mucosal membranes across the body. He chose to focus on cholera because he wanted to replicate the way traditional vaccines work to get mucosal membranes in the digestive tract to produce an immune response. The difference is that his team is creating a food-based vaccine to induce this immune response. They are also solely focusing on getting the vaccine to induce antibodies for the cholera toxin. Since the cholera toxin is responsible for bacteria sticking to gut cells, the hope is that they can stop this process by producing antibodies for the cholera toxin. Current cholera vaccines target the cholera bacteria or both the bacteria and the toxin.
David Pascual, an expert in infectious diseases and immunology at the University of Florida, thinks that the MucoRice vaccine has huge promise. "I truly believe that the development of a food-based vaccine can be effective. CTB has a natural affinity for sampling cells in the gut to adhere, be processed, and then stimulate our immune system, he says. "In addition to vaccinating the gut, MucoRice has the potential to touch other mucosal surfaces in the mouth, which can help generate an immune response locally in the mouth and distally in the gut."
Cost Effectiveness
Kiyono says the MucoRice vaccine is much cheaper to produce than a traditional vaccine. Current vaccines need expensive bioreactors to grow cell cultures under very controlled, sterile conditions. This makes them expensive to manufacture, as different types of cell cultures need to be grown in separate buildings to avoid any chance of contamination. MucoRice doesn't require such an expensive manufacturing process because the rice plants themselves act as bioreactors.
The MucoRice vaccine also doesn't require the high cost of cold storage. It can be stored at room temperature for up to three years unlike traditional vaccines. "Plant-based vaccine development platforms present an exciting tool to reduce vaccine manufacturing costs, expand vaccine shelf life, and remove refrigeration requirements, all of which are factors that can limit vaccine supply and accessibility," Breakwell says.
Kathleen Hefferon, a microbiologist at Cornell University agrees. "It is much less expensive than a traditional vaccine, by a long shot," she says. "The fact that it is made in rice means the vaccine can be stored for long periods on the shelf, without losing its activity."
A plant-based vaccine may even be able to address vaccine hesitancy, which has become a growing problem in recent years. Hefferon suggests that "using well-known food plants may serve to reduce the anxiety of some vaccine hesitant people."
Challenges of Plant Vaccines
Despite their advantages, no plant-based vaccines have been commercialized for human use. There are a number of reasons for this, ranging from the potential for too much variation in plants to the lack of facilities large enough to grow crops that comply with good manufacturing practices. Several plant vaccines for diseases like HIV and COVID-19 are in development, but they're still in early stages.
In developing the MucoRice vaccine, scientists at the University of Tokyo have tried to overcome some of the problems with plant vaccines. They've created a closed facility where they can grow rice plants directly in nutrient-rich water rather than soil. This ensures they can grow crops all year round in a space that satisfies regulations. There's also less chance for variation since the environment is tightly controlled.
Clinical Trials and Beyond
After successfully growing rice plants containing the vaccine, the team carried out their first clinical trial. It was completed early this year. Thirty participants received a placebo and 30 received the vaccine. They were all Japanese men between the ages of 20 and 40 years old. 60 percent produced antibodies against the cholera toxin with no side effects. It was a promising result. However, there are still some issues Kiyono's team need to address.
The vaccine may not provide enough protection on its own. The antigen in any vaccine is the substance it contains to induce an immune response. For the MucoRice vaccine, the antigen is not the cholera bacteria itself but the cholera toxin the bacteria produces.
"The development of the antigen in rice is innovative," says David Sack, a professor at John Hopkins University and expert in cholera vaccine development. "But antibodies against only the toxin have not been very protective. The major protective antigen is thought to be the LPS." LPS, or lipopolysaccharide, is a component of the outer wall of the cholera bacteria that plays an important role in eliciting an immune response.
The Japanese team is considering getting the rice to also express the O antigen, a core part of the LPS. Further investigation and clinical trials will look into improving the vaccine's efficacy.
Beyond cholera, Kiyono hopes that the vaccine platform could one day be used to make cost-effective vaccines for other pathogens, such as norovirus or coronavirus.
"We believe the MucoRice system may become a new generation of vaccine production, storage, and delivery system."
Scientists Just Created Liquid Solar Power That Can Be Stored for 18 Years
A team of Swedish scientists has gathered solar power so pure, that until recently, capturing it was an impossibility.
Look no further than this week's climate strikes for evidence that millions of people are passionate about curbing global warming.
Unlike relatively limited solar panel energy storage, norbornadiene can potentially maintain its potency for years.
But even potential solutions, like alternative meats, have their own challenges. Some scientists are putting their focus on the sun to help balance out our energy consumption.
In fact, they are gathering solar power so pure that, until recently, capturing it was an impossibility.
The Lowdown
A group of Swedish scientists has created a liquid called norbornadiene. This liquid sunshine can capture up to 30 percent of raw solar power. To put it in perspective, the best publicly available solar panels can harness 21 percent. Norbornadiene would bring in about 50 percent more power – a significant difference in energy efficiency.
Most notably, unlike relatively limited solar panel energy storage, norbornadiene can potentially maintain its potency for years. We could have the ability to collect and store premium solar power, making it easier for current and future generations to use fossil and nuclear fuel alternatives.
"The norbornadiene molecules that we have made have very good properties, in terms of solar energy capture efficiency, storage time and energy density," says team lead Dr. Kasper Moth-Poulson of the Chamlers University of Technology. "They can store energy without the need for insulation materials for 18 or more years."
Next Up
Swedish scientist Moth-Poulsen and his team have been testing the norbornadiene on the physics building roof at the Chalmers University of Technology. Once activated, it heats up to just below boiling and provides enough power to be useful.
The energy density is 250 watt-hours per kilogram, twice the strength of Tesla's popular Powerall battery.
It requires potentially toxic solvents, like a cobalt-based activator, to transform into its full potential. The team is currently trying to find less-hazardous catalysts to help transform the norbornadiene to its active form, quadricyclane. Exposing it to sunlight is the main way to reactivate the norbornadiene's power. Over time, scientists will likely make it more efficient with less toxic agents.
The energy density is 250 watt-hours per kilogram, twice the strength of Tesla's popular Powerall battery.
Open Questions
The biggest question is safety, perceived or otherwise: Are you ready to drive around with 250 kWh of pure solar in your Hyundai? Norbornadiene may be stable in a hermetically sealed lab, but sculpting it for everyday use requires another level of security.
The half-life of the sunshine power is also an estimate, too. The challenge with new scientific substances is you don't know how the matter will evolve over time. It is easy to be overly optimistic about this one discovery being the key to our energy needs. For the time being, it is wiser to look at norbornadiene as a progressive step rather than a revolutionary one.
Even at its least effective, norbornadiene and its related material is a step toward us utilizing the one natural resource that won't run out for generations. In the short-term, a stable form of it could offset our fossil and nuclear fuel use and even help lower the carbon footprint made by long-distance transportation. It will be fascinating to see what future aircraft builders, home designers and even car manufacturers do as the solar technology conversation heats up.
Moth-Poulsen wants norbornadiene to be a definitive part of the climate change puzzle.
"I hope that in five years, we will see the first products based on our molecules and could help mitigate the daily variations in temperature," he says. "This will lead to increased thermal comfort and reduced energy consumption for heating and cooling."
Virtual Reality is Making Medical Care for Kids Less Scary and Painful
A patient at Children's Hospital Los Angeles (Courtesy of Children's Hospital Los Angeles) plus Bear Blast, developed by AppliedVR.
A blood draw is not normally a fun experience, but these days, virtual reality technology is changing that.
Instead of watching a needle go into his arm, a child wearing a VR headset at Children's Hospital Los Angeles can play a game throwing balls at cartoon bears. In Seattle, at the University of Washington, a burn patient can immerse herself in a soothing snow scene. And at the University of Miami Hospital, a five-minute skin biopsy can become an exciting ride at an amusement park.
VR is transforming once-frightening medical encounters for kids, from blood draws to biopsies to pre-surgical prep, into tolerable ones.
It's literally a game changer, says pediatric neurosurgeon Kurtis Auguste, who uses the tool to help explain pending operations to his young patients and their families. The virtual reality 3-D portrait of their brain is recreated from an MRI, originally to help plan the surgery. The image of normally bland tissue is painted with false colors to better see the boundaries and anomalies of each component. It can be rotated, viewed from every possible angle, zoomed in and out; incisions can be made and likely results anticipated. Auguste has extended its use to patients and families.
"The moment you put these headsets on the kids, we immediately have a link, because honestly, this is how they communicate with each other," says Auguste. "We're all sitting around the table playing games. It's really bridged the distance between me, the pediatric specialist, and my patients" at the Benioff Children's Hospital Oakland, now affiliated with the University of California San Francisco School of Medicine.
The VR experience engages people where they are, immersing them in the environment rather than lecturing them. And it seems to work in all environments, across age and cultural differences, leading to a better grasp of what will be undertaken. That understanding is crucial to meaningful informed consent for surgery. It is particularly relevant for safety-net hospitals, which includes most children's hospitals, because often members of the families were born elsewhere and may have limited understanding of English, not to mention advanced medicine.
Targeting pain
"We're trying to target ways that we can decrease pain, anxiety, fear – what people usually experience as a function of a needle," says Jeffrey Gold, a pioneer in adapting VR at Children's Hospital Los Angeles. He ran the pain clinic there and in 2004 initially focused on phlebotomy, simple blood draws. Many of their kids require frequent blood draws to monitor serious chronic conditions such as diabetes, HIV infection, sickle cell disease, and other conditions that affect the heart, liver, kidneys and other organs.
The scientific explanation of how VR works for pain relief draws upon two basic principles of brain function. The first is "top down inhibition," Gold explains. "We all have the inherent capacity to turn down signals once we determine that signal is no longer harmful, dangerous, hurtful, etc. That's how our brain operates on purpose. It's not just a distraction, it's actually your brain stopping the pain signal at the spinal cord before it can fire all the way up to the frontal lobe."
Second is the analgesic effect from endorphins. "If you're in a gaming environment, and you're having fun and you're laughing and giggling, you are actually releasing endorphins...a neurochemical reaction at the synaptic level of the brain," he says.
Part of what makes VR effective is "what's called a cognitive load, where you have to actually learn something and do something," says Gold. He has worked with developers on a game call Bear Blast, which has proven to be effective in a clinical trial for mitigating pain. But he emphasizes, it is not a one-size-fits all; the programs and patients need to be evaluated to understand what works best for each case.
Gold was a bit surprised to find that VR "actually facilitates quicker blood draws," because the staff doesn't have to manage the kids' anxiety, so "they require fewer needle sticks." The kids, parents, and staff were all having a good time, "and that's a big win when everybody is benefiting." About two years ago the hospital made VR an option that patients can request in the phlebotomy lab, and about half of kids age 4 and older choose to do so.
The technology "gets the kids engaged and performing the activity the way we want them to" to maximize recovery.
VR reduces or eliminates the need to use sedation or anesthesia, which carries a small but real risk of an adverse reaction. And important to parents, it eliminates the recovery time from using sedation, which shortens the visit and time missed from school and work.
A more intriguing question is whether reducing fear and anxiety in early-life experiences with the healthcare system through activities like VR will have a long-term affect on kids' attitudes toward medicine as they grow older. "If you're a screaming meemie when you come get your blood draw when you're five or seven, you're still that anxious adolescent or adult who is all quivering and sweating and avoiding healthcare," Gold says. "That's a longitudinal health outcome I'd love to get my hands on in 10-15 years from now."
Broader applications
Dermatologist Hadar Lev-Tov read about the use of VR to treat pain and decided to try it in his practice at the University of Miami Hospital. He thought, "OK, this is low risk, it's easy to do. So we got some equipment and got it done." It was so affordable he paid for it out of his own pocket, rather than wait to go through administrative channels. The results were so interesting that he decided to publish it as a series of case studies with a wide variety of patients and types of procedures.
Some of them, such as freezing off warts, are not particularly painful. "But there can be a lot of anxiety, especially for kids, which can be worse than pain and can disrupt the procedure." It can trigger a non-rational, primal fight or flight response in the limbic region of the brain.
Adults understand the need for a biopsy of a skin growth and tolerate what might be a momentary flick of pain. "But for a kid you think twice about a biopsy, both because it's a hassle and because it could be a traumatic event for a child," says Lev-Tov. VR has helped to allay such fears and improve medical care.
Integrating VR into practice has been relatively easy, primarily focusing on simple training for staff and ensuring that standard infection control practices are used in handling equipment that is used by different patients. More mundane issues are ensuring that the play back and wi-fi equipment are functioning properly. He has had a few complaints from kids when the procedure is competed and the VR is turned off prematurely, which is why he favors programs like a roller coaster ride that lasts about five minutes, ample time to take a biopsy or two.
The future is today
The pediatric neurosurgeon Auguste is collaborating with colleagues at Oakland Children's to expand use of VR into different areas of care. Cancer specialists often use a port, a bubble installed under the skin in the chest of the child, to administer chemotherapy. But the young patient's curiosity often draws their attention downward to the port and their chin can potentially contaminate or obstruct it, interfering with the procedure. So the team developed a VR game involving birds that requires players to move their heads upward, away from the port, improving administration of the drugs and reducing the risk of infection.
Innovative use of VR just may be one tool that actually makes kids eager to visit the doctor.
Other games are being developed for rehabilitation that require the use of specific nerve and muscle combinations. The technology "gets the kids engaged and performing the activity the way we want them to" to maximize recovery, Auguste explains. "We can monitor their progress by the score on the game, and if it plateaus, maybe switch to another game."
Another project is trying to ease the anxiety and confusion of the patient and family experience within the hospital itself. Hospital staff are creating a personalized VR introductory walking tour that leads from the parking garage through the maze of structures and corridors in the hospital complex to Dr. Auguste's office, phlebotomy, the MRI site, and other locations they might visit. The goal is to make them familiar with key landmarks before they even set foot in the facility. "So when they come the day of the visit they have already taken that exact same path, hopefully more than once."
"They don't miss their MRI appointment and therefore they don't miss their clinical appointment with me," says Auguste. It reduces patient anxiety about the encounter and from the hospital's perspective, it will reduce costs of missed and rescheduled visits simply because patients did not go to the right place at the right time.
The VR visit will be emailed to patients ahead of time and they can watch it on a smartphone installed in a disposable cardboard viewer. Oakland Children's hopes to have the system in place by early next year. Auguste says their goal in using VR, like other health care providers across the country, is "to streamline the entire patient experience."
Innovative use of VR just may be one tool that actually makes kids eager to visit the doctor. That would be a boon to kids, parents, and the health of America.