A mid-1970s photo of the author's father, and him holding a grandchild in 2012.
[Editor's Note: This piece is the winner of our 2019 essay contest, which prompted readers to reflect on the question: "How has an advance in science or medicine changed your life?"]
My father did not expect to live past the age of 50. Neither of his parents had done so. And he also knew how he would die: by heart attack, just as his father did.
In July of 1976, he had his first heart attack, days before his 40th birthday.
My dad lived the first 40 years of his life with this knowledge buried in his bones. He started smoking at the age of 12, and was drinking before he was old enough to enlist in the Navy. He had a sarcastic, often cruel, sense of humor that could drive my mother, my sister and me into tears. He was not an easy man to live with, but that was okay by him - he didn't expect to live long.
In July of 1976, he had his first heart attack, days before his 40th birthday. I was 13, and my sister was 11. He needed quadruple bypass surgery. Our small town hospital was not equipped to do this type of surgery; he would have to be transported 40 miles away to a heart center. I understood this journey to mean that my father was seriously ill, and might die in the hospital, away from anyone he knew. And my father knew a lot of people - he was a popular high school English teacher, in a town with only three high schools. He knew generations of students and their parents. Our high school football team did a blood drive in his honor.
During a trip to Disney World in 1974, Dad was suffering from angina the entire time but refused to tell me (left) and my sister, Kris.
Quadruple bypass surgery in 1976 meant that my father's breastbone was cut open by a sternal saw. His ribcage was spread wide. After the bypass surgery, his bones would be pulled back together, and tied in place with wire. The wire would later be pulled out of his body when the bones knitted back together. It would take months before he was fully healed.
Dad was in the hospital for the rest of the summer and into the start of the new school year. Going to visit him was farther than I could ride my bicycle; it meant planning a trip in the car and going onto the interstate. The first time I was allowed to visit him in the ICU, he was lying in bed, and then pushed himself to sit up. The heart monitor he was attached to spiked up and down, and I fainted. I didn't know that heartbeats change when you move; television medical dramas never showed that - I honestly thought that I had driven my father into another heart attack.
Only a few short years after that, my father returned to the big hospital to have his heart checked with a new advance in heart treatment: a CT scan. This would allow doctors to check for clogged arteries and treat them before a fatal heart attack. The procedure identified a dangerous blockage, and my father was admitted immediately. This time, however, there was no need to break bones to get to the problem; my father was home within a month.
During the late 1970's, my father changed none of his habits. He was still smoking, and he continued to drink. But now, he was also taking pills - pills to manage the pain. He would pop a nitroglycerin tablet under his tongue whenever he was experiencing angina (I have a vivid memory of him doing this during my driving lessons), but he never mentioned that he was in pain. Instead, he would snap at one of us, or joke that we were killing him.
I think he finally determined that, if he was going to have these extra decades of life, he wanted to make them count.
Being the kind of guy he was, my father never wanted to talk about his health. Any admission of pain implied that he couldn't handle pain. He would try to "muscle through" his angina, as if his willpower would be stronger than his heart muscle. His efforts would inevitably fail, leaving him angry and ready to lash out at anyone or anything. He would blame one of us as a reason he "had" to take valium or pop a nitro tablet. Dinners often ended in shouts and tears, and my father stalking to the television room with a bottle of red wine.
In the 1980's while I was in college, my father had another heart attack. But now, less than 10 years after his first, medicine had changed: our hometown hospital had the technology to run dye through my father's blood stream, identify the blockages, and do preventative care that involved statins and blood thinners. In one case, the doctors would take blood vessels from my father's legs, and suture them to replace damaged arteries around his heart. New advances in cholesterol medication and treatments for angina could extend my father's life by many years.
My father decided it was time to quit smoking. It was the first significant health step I had ever seen him take. Until then, he treated his heart issues as if they were inevitable, and there was nothing that he could do to change what was happening to him. Quitting smoking was the first sign that my father was beginning to move out of his fatalistic mindset - and the accompanying fatal behaviors that all pointed to an early death.
In 1986, my father turned 50. He had now lived longer than either of his parents. The habits he had learned from them could be changed. He had stopped smoking - what else could he do?
It was a painful decade for all of us. My parents divorced. My sister quit college. I moved to the other side of the country and stopped speaking to my father for almost 10 years. My father remarried, and divorced a second time. I stopped counting the number of times he was in and out of the hospital with heart-related issues.
In the early 1990's, my father reached out to me. I think he finally determined that, if he was going to have these extra decades of life, he wanted to make them count. He traveled across the country to spend a week with me, to meet my friends, and to rebuild his relationship with me. He did the same with my sister. He stopped drinking. He was more forthcoming about his health, and admitted that he was taking an antidepressant. His humor became less cruel and sadistic. He took an active interest in the world. He became part of my life again.
The 1990's was also the decade of angioplasty. My father explained it to me like this: during his next surgery, the doctors would place balloons in his arteries, and inflate them. The balloons would then be removed (or dissolve), leaving the artery open again for blood. He had several of these surgeries over the next decade.
When my father was in his 60's, he danced at with me at my wedding. It was now 10 years past the time he had expected to live, and his life was transformed. He was living with a woman I had known since I was a child, and my wife and I would make regular visits to their home. My father retired from teaching, became an avid gardener, and always had a home project underway. He was a happy man.
Dancing with my father at my wedding in 1998.
Then, in the mid 2000's, my father faced another serious surgery. Years of arterial surgery, angioplasty, and damaged heart muscle were taking their toll. He opted to undergo a life-saving surgery at Cleveland Clinic. By this time, I was living in New York and my sister was living in Arizona. We both traveled to the Midwest to be with him. Dad was unconscious most of the time. We took turns holding his hand in the ICU, encouraging him to regain his will to live, and making outrageous threats if he didn't listen to us.
The nursing staff were wonderful. I remember telling them that my father had never expected to live this long. One of the nurses pointed out that most of the patients in their ward were in their 70's and 80's, and a few were in their 90's. She reminded me that just a decade earlier, most hospitals were unwilling to do the kind of surgery my father had received on patients his age. In the first decade of the 21st century, however, things were different: 90-year-olds could now undergo heart surgery and live another decade. My father was on the "young" side of their patients.
The Cleveland Clinic visit would be the last major heart surgery my father would have. Not that he didn't return to his local hospital a few times after that: he broke his neck -- not once, but twice! -- slipping on ice. And in the 2010's, he began to show signs of dementia, and needed more home care. His partner, who had her own health issues, was not able to provide the level of care my father needed. My sister invited him to move in with her, and in 2015, I traveled with him to Arizona to get him settled in.
After a few months, he accepted home hospice. We turned off his pacemaker when the hospice nurse explained to us that the job of a pacemaker is to literally jolt a patient's heart back into beating. The jolts were happening more and more frequently, causing my Dad additional, unwanted pain.
My father in 2015, a few months before his death.
My father died in February 2016. His body carried the scars and implants of 30 years of cardiac surgeries, from the ugly breastbone scar from the 1970's to scars on his arms and legs from borrowed blood vessels, to the tiny red circles of robotic incisions from the 21st century. The arteries and veins feeding his heart were a patchwork of transplanted leg veins and fragile arterial walls pressed thinner by balloons.
And my father died with no regrets or unfinished business. He died in my sister's home, with his long-time partner by his side. Medical advancements had given him the opportunity to live 30 years longer than he expected. But he was the one who decided how to live those extra years. He was the one who made the years matter.
Researchers are looking to engineer chocolate with less oil, which could reduce some of its detriments to health.
Building a 3D tongue
The team began by building a 3D tongue to analyze the physical process by which chocolate breaks down inside the mouth.
As part of the effort, reported earlier this year in the scientific journal ACS Applied Materials and Interfaces, the team studied a large variety of human tongues with the intention to build an “average” 3D model, says Soltanahmadi, a lubrication scientist. When it comes to edible substances, lubrication science looks at how food feels in the mouth and can help design foods that taste better and have more satisfying texture or health benefits.
There are variations in how people enjoy chocolate; some chew it while others “lick it” inside their mouths.
Tongue impressions from human participants studied using optical imaging helped the team build a tongue with key characteristics. “Our tongue is not a smooth muscle, it’s got some texture, it has got some roughness,” Soltanahmadi says. From those images, the team came up with a digital design of an average tongue and, using 3D printed molds, built a “mimic tongue.” They also added elastomers—such as silicone or polyurethane—to mimic the roughness, the texture and the mechanical properties of a real tongue. “Wettability" was another key component of the 3D tongue, Soltanahmadi says, referring to whether a surface mixes with water (hydrophilic) or, in the case of oil, resists it (hydrophobic).
Notably, the resulting artificial 3D-tongues looked nothing like the human version, but they were good mimics. The scientists also created “testing kits” that produced data on various physical parameters. One such parameter was viscosity, the measure of how gooey a food or liquid is — honey is more viscous compared to water, for example. Another was tribology, which defines how slippery something is — high fat yogurt is more slippery than low fat yogurt; milk can be more slippery than water. The researchers then mixed chocolate with artificial saliva and spread it on the 3D tongue to measure the tribology and the viscosity. From there they were able to study what happens inside the mouth when we eat chocolate.
The team focused on the stages of lubrication and the location of the fat in the chocolate, a process that has rarely been researched.
The artificial 3D-tongues look nothing like human tongues, but they function well enough to do the job.
Courtesy Anwesha Sarkar and University of Leeds
The oral processing of chocolate
We process food in our mouths in several stages, Soltanahmadi says. And there is variation in these stages depending on the type of food. So, the oral processing of a piece of meat would be different from, say, the processing of jelly or popcorn.
There are variations with chocolate, in particular; some people chew it while others use their tongues to explore it (within their mouths), Soltanahmadi explains. “Usually, from a consumer perspective, what we find is that if you have a luxury kind of a chocolate, then people tend to start with licking the chocolate rather than chewing it.” The researchers used a luxury brand of dark chocolate and focused on the process of licking rather than chewing.
As solid cocoa particles and fat are released, the emulsion envelops the tongue and coats the palette creating a smooth feeling of chocolate all over the mouth. That tactile sensation is part of the chocolate’s hedonistic appeal we crave.
Understanding the make-up of the chocolate was also an important step in the study. “Chocolate is a composite material. So, it has cocoa butter, which is oil, it has some particles in it, which is cocoa solid, and it has sugars," Soltanahmadi says. "Dark chocolate has less oil, for example, and less sugar in it, most of the time."
The researchers determined that the oral processing of chocolate begins as soon as it enters a person’s mouth; it starts melting upon exposure to one’s body temperature, even before the tongue starts moving, Soltanahmadi says. Then, lubrication begins. “[Saliva] mixes with the oily chocolate and it makes an emulsion." An emulsion is a fluid with a watery (or aqueous) phase and an oily phase. As chocolate breaks down in the mouth, that solid piece turns into a smooth emulsion with a fatty film. “The oil from the chocolate becomes droplets in a continuous aqueous phase,” says Soltanahmadi. In other words, as solid cocoa particles and fat are released, the emulsion envelops the tongue and coats the palette, creating a smooth feeling of chocolate all over the mouth. That tactile sensation is part of the chocolate’s hedonistic appeal we crave, says Soltanahmadi.
Finding the sweet spot
After determining how chocolate is orally processed, the research team wanted to find the exact sweet spot of the breakdown of solid cocoa particles and fat as they are released into the mouth. They determined that the epicurean pleasure comes only from the chocolate's outer layer of fat; the secondary fatty layers inside the chocolate don’t add to the sensation. It was this final discovery that helped the team determine that it might be possible to produce healthier chocolate that would contain less oil, says Soltanahmadi. And therefore, less fat.
Rongjia Tao, a physicist at Temple University in Philadelphia, thinks the Leeds study and the concept behind it is “very interesting.” Tao, himself, did a study in 2016 and found he could reduce fat in milk chocolate by 20 percent. He believes that the Leeds researchers’ discovery about the first layer of fat being more important for taste than the other layer can inform future chocolate manufacturing. “As a scientist I consider this significant and an important starting point,” he says.
Chocolate is rich in polyphenols, naturally occurring compounds also found in fruits and vegetables, such as grapes, apples and berries. Research found that plant polyphenols can protect against cancer, diabetes and osteoporosis as well as cardiovascular ad neurodegenerative diseases.
Not everyone thinks it’s a good idea, such as chef Michael Antonorsi, founder and owner of Chuao Chocolatier, one of the leading chocolate makers in the U.S. First, he says, “cacao fat is definitely a good fat.” Second, he’s not thrilled that science is trying to interfere with nature. “Every time we've tried to intervene and change nature, we get things out of balance,” says Antonorsi. “There’s a reason cacao is botanically known as food of the gods. The botanical name is the Theobroma cacao: Theobroma in ancient Greek, Theo is God and Brahma is food. So it's a food of the gods,” Antonorsi explains. He’s doubtful that a chocolate made only with a top layer of fat will produce the same epicurean satisfaction. “You're not going to achieve the same sensation because that surface fat is going to dissipate and there is no fat from behind coming to take over,” he says.
Without layers of fat, Antonorsi fears the deeply satisfying experiential part of savoring chocolate will be lost. The University of Leeds team, however, thinks that it may be possible to make chocolate healthier - when consumed in limited amounts - without sacrificing its taste. They believe the concept of less fatty but no less slick chocolate will resonate with at least some chocolate-makers and consumers, too.
Chocolate already contains some healthful compounds. Its cocoa particles have “loads of health benefits,” says Soltanahmadi. Dark chocolate usually has more cocoa than milk chocolate. Some experts recommend that dark chocolate should contain at least 70 percent cocoa in order for it to offer some health benefit. Research has shown that the cocoa in chocolate is rich in polyphenols, naturally occurring compounds also found in fruits and vegetables, such as grapes, apples and berries. Research has shown that consuming plant polyphenols can be protective against cancer, diabetes and osteoporosis as well as cardiovascular and neurodegenerative diseases.
“So keeping the healthy part of it and reducing the oily part of it, which is not healthy, but is giving you that indulgence of it … that was the final aim,” Soltanahmadi says. He adds that the team has been approached by individuals in the chocolate industry about their research. “Everyone wants to have a healthy chocolate, which at the same time tastes brilliant and gives you that self-indulging experience.”
Probiotic bacteria can be engineered to fight antibiotic-resistant superbugs by releasing chemicals that kill them.
In recent years, researchers have been exploring a promising avenue: the use of synthetic biology to engineer new bacteria that may work better than antibiotics. The need continues to grow, as a Lancet study linked antibiotic resistance to over 1.27 million deaths worldwide in 2019, surpassing HIV/AIDS and malaria. The western sub-Saharan Africa region had the highest death rate (27.3 people per 100,000).
Researchers warn that if nothing changes, by 2050, antibiotic resistance could kill 10 million people annually.
To make it worse, our remedy pipelines are drying up. Out of the 18 biggest pharmaceutical companies, 15 abandoned antibiotic development by 2013. According to the AMR Action Fund, venture capital has remained indifferent towards biotech start-ups developing new antibiotics. In 2019, at least two antibiotic start-ups filed for bankruptcy. As of December 2020, there were 43 new antibiotics in clinical development. But because they are based on previously known molecules, scientists say they are inadequate for treating multidrug-resistant bacteria. Researchers warn that if nothing changes, by 2050, antibiotic resistance could kill 10 million people annually.
The rise of synthetic biology
To circumvent this dire future, scientists have been working on alternative solutions using synthetic biology tools, meaning genetically modifying good bacteria to fight the bad ones.
From the time life evolved on earth around 3.8 billion years ago, bacteria have engaged in biological warfare. They constantly strategize new methods to combat each other by synthesizing toxic proteins that kill competition.
For example, Escherichia coli produces bacteriocins or toxins to kill other strains of E.coli that attempt to colonize the same habitat. Microbes like E.coli (which are not all pathogenic) are also naturally present in the human microbiome. The human microbiome harbors up to 100 trillion symbiotic microbial cells. The majority of them are beneficial organisms residing in the gut at different compositions.
The chemicals that these “good bacteria” produce do not pose any health risks to us, but can be toxic to other bacteria, particularly to human pathogens. For the last three decades, scientists have been manipulating bacteria’s biological warfare tactics to our collective advantage.
In the late 1990s, researchers drew inspiration from electrical and computing engineering principles that involve constructing digital circuits to control devices. In certain ways, every cell in living organisms works like a tiny computer. The cell receives messages in the form of biochemical molecules that cling on to its surface. Those messages get processed within the cells through a series of complex molecular interactions.
Synthetic biologists can harness these living cells’ information processing skills and use them to construct genetic circuits that perform specific instructions—for example, secrete a toxin that kills pathogenic bacteria. “Any synthetic genetic circuit is merely a piece of information that hangs around in the bacteria’s cytoplasm,” explains José Rubén Morones-Ramírez, a professor at the Autonomous University of Nuevo León, Mexico. Then the ribosome, which synthesizes proteins in the cell, processes that new information, making the compounds scientists want bacteria to make. “The genetic circuit remains separated from the living cell’s DNA,” Morones-Ramírez explains. When the engineered bacteria replicates, the genetic circuit doesn’t become part of its genome.
Highly intelligent by bacterial standards, some multidrug resistant V. cholerae strains can also “collaborate” with other intestinal bacterial species to gain advantage and take hold of the gut.
In 2000, Boston-based researchers constructed an E.coli with a genetic switch that toggled between turning genes on and off two. Later, they built some safety checks into their bacteria. “To prevent unintentional or deleterious consequences, in 2009, we built a safety switch in the engineered bacteria’s genetic circuit that gets triggered after it gets exposed to a pathogen," says James Collins, a professor of biological engineering at MIT and faculty member at Harvard University’s Wyss Institute. “After getting rid of the pathogen, the engineered bacteria is designed to switch off and leave the patient's body.”
Overuse and misuse of antibiotics causes resistant strains to evolve
Adobe Stock
Seek and destroy
As the field of synthetic biology developed, scientists began using engineered bacteria to tackle superbugs. They first focused on Vibrio cholerae, which in the 19th and 20th century caused cholera pandemics in India, China, the Middle East, Europe, and Americas. Like many other bacteria, V. cholerae communicate with each other via quorum sensing, a process in which the microorganisms release different signaling molecules, to convey messages to its brethren. Highly intelligent by bacterial standards, some multidrug resistant V. cholerae strains can also “collaborate” with other intestinal bacterial species to gain advantage and take hold of the gut. When untreated, cholera has a mortality rate of 25 to 50 percent and outbreaks frequently occur in developing countries, especially during floods and droughts.
Sometimes, however, V. cholerae makes mistakes. In 2008, researchers at Cornell University observed that when quorum sensing V. cholerae accidentally released high concentrations of a signaling molecule called CAI-1, it had a counterproductive effect—the pathogen couldn’t colonize the gut.
So the group, led by John March, professor of biological and environmental engineering, developed a novel strategy to combat V. cholerae. They genetically engineered E.coli to eavesdrop on V. cholerae communication networks and equipped it with the ability to release the CAI-1 molecules. That interfered with V. cholerae progress. Two years later, the Cornell team showed that V. cholerae-infected mice treated with engineered E.coli had a 92 percent survival rate.
These findings inspired researchers to sic the good bacteria present in foods like yogurt and kimchi onto the drug-resistant ones.
Three years later in 2011, Singapore-based scientists engineered E.coli to detect and destroy Pseudomonas aeruginosa, an often drug-resistant pathogen that causes pneumonia, urinary tract infections, and sepsis. Once the genetically engineered E.coli found its target through its quorum sensing molecules, it then released a peptide, that could eradicate 99 percent of P. aeruginosa cells in a test-tube experiment. The team outlined their work in a Molecular Systems Biology study.
“At the time, we knew that we were entering new, uncharted territory,” says lead author Matthew Chang, an associate professor and synthetic biologist at the National University of Singapore and lead author of the study. “To date, we are still in the process of trying to understand how long these microbes stay in our bodies and how they might continue to evolve.”
More teams followed the same path. In a 2013 study, MIT researchers also genetically engineered E.coli to detect P. aeruginosa via the pathogen’s quorum-sensing molecules. It then destroyed the pathogen by secreting a lab-made toxin.
Probiotics that fight
A year later in 2014, a Nature study found that the abundance of Ruminococcus obeum, a probiotic bacteria naturally occurring in the human microbiome, interrupts and reduces V.cholerae’s colonization— by detecting the pathogen’s quorum sensing molecules. The natural accumulation of R. obeum in Bangladeshi adults helped them recover from cholera despite living in an area with frequent outbreaks.
The findings from 2008 to 2014 inspired Collins and his team to delve into how good bacteria present in foods like yogurt and kimchi can attack drug-resistant bacteria. In 2018, Collins and his team developed the engineered probiotic strategy. They tweaked a bacteria commonly found in yogurt called Lactococcus lactis to treat cholera.
Engineered bacteria can be trained to target pathogens when they are at their most vulnerable metabolic stage in the human gut. --José Rubén Morones-Ramírez.
More scientists followed with more experiments. So far, researchers have engineered various probiotic organisms to fight pathogenic bacteria like Staphylococcus aureus (leading cause of skin, tissue, bone, joint and blood infections) and Clostridium perfringens (which causes watery diarrhea) in test-tube and animal experiments. In 2020, Russian scientists engineered a probiotic called Pichia pastoris to produce an enzyme called lysostaphin that eradicated S. aureus in vitro. Another 2020 study from China used an engineered probiotic bacteria Lactobacilli casei as a vaccine to prevent C. perfringens infection in rabbits.
In a study last year, Ramírez’s group at the Autonomous University of Nuevo León, engineered E. coli to detect quorum-sensing molecules from Methicillin-resistant Staphylococcus aureus or MRSA, a notorious superbug. The E. coli then releases a bacteriocin that kills MRSA. “An antibiotic is just a molecule that is not intelligent,” says Ramírez. “On the other hand, engineered bacteria can be trained to target pathogens when they are at their most vulnerable metabolic stage in the human gut.”
Collins and Timothy Lu, an associate professor of biological engineering at MIT, found that engineered E. coli can help treat other conditions—such as phenylketonuria, a rare metabolic disorder, that causes the build-up of an amino acid phenylalanine. Their start-up Synlogic aims to commercialize the technology, and has completed a phase 2 clinical trial.
Circumventing the challenges
The bacteria-engineering technique is not without pitfalls. One major challenge is that beneficial gut bacteria produce their own quorum-sensing molecules that can be similar to those that pathogens secrete. If an engineered bacteria’s biosensor is not specific enough, it will be ineffective.
Another concern is whether engineered bacteria might mutate after entering the gut. “As with any technology, there are risks where bad actors could have the capability to engineer a microbe to act quite nastily,” says Collins of MIT. But Collins and Ramírez both insist that the chances of the engineered bacteria mutating on its own are virtually non-existent. “It is extremely unlikely for the engineered bacteria to mutate,” Ramírez says. “Coaxing a living cell to do anything on command is immensely challenging. Usually, the greater risk is that the engineered bacteria entirely lose its functionality.”
However, the biggest challenge is bringing the curative bacteria to consumers. Pharmaceutical companies aren’t interested in antibiotics or their alternatives because it’s less profitable than developing new medicines for non-infectious diseases. Unlike the more chronic conditions like diabetes or cancer that require long-term medications, infectious diseases are usually treated much quicker. Running clinical trials are expensive and antibiotic-alternatives aren’t lucrative enough.
“Unfortunately, new medications for antibiotic resistant infections have been pushed to the bottom of the field,” says Lu of MIT. “It's not because the technology does not work. This is more of a market issue. Because clinical trials cost hundreds of millions of dollars, the only solution is that governments will need to fund them.” Lu stresses that societies must lobby to change how the modern healthcare industry works. “The whole world needs better treatments for antibiotic resistance.”