Call them what you will: change makers, innovators, thought leaders, visionaries. In ways large and small, they fight. They disrupt. They take risks. They push boundaries to change the way we see the world or live in it.

From Archimedes to Zeppelin, the accomplishments of great visionaries have filled history books. However, today’s innovators face their own set of challenges as the world changes at warp speed.

To be a change maker has always required intensity. “These people are driven by some cause that compels them to find the courage and take certain risks and work damn hard at it,” said author Simon Sinek.

Here’s a look at some of the emerging game-changers who are using medicine and science to improve our quality of life. 

Working to treat the entire patient

Rebecca Onie, co-founder and chief executive emerita of Health Leads

Rebecca Onie likes to tell the story of a teenage boy who was mysteriously losing weight. His doctor, stumped, huddled with other caregivers to decide which medical tests to run. Then someone asked the boy a simple question: Are you hungry? It turned out that the teen had been homeless for weeks and had been too embarrassed to speak up.

To Onie, that story offers an example of what is wrong with the U.S. health care system: It can be so focused on medicine that it misses the social issues that drive health.

For more than 20 years since she co-founded the nonprofit Health Leads, she has helped push this more holistic view. Now, Onie, 40, is tackling an even bigger problem. She’s begun an initiative to help bring together insurers, foundations, medical societies, state governments, community organizations and others who embrace this broader view of health. “It’s that disconnect that I think creates the opportunity for real change,” Onie said.

Gail Boudreaux, chief executive of Anthem, one of the nation’s largest health insurers, said she had long been impressed with Onie’s big-picture perspective, her ability to bring people together and her understanding that success came only with scale. “She’s probably one of the most passionate people about this issue that I’ve ever met,” she said.

Using empathy and innovation

Antoni Ribas, professor of medicine, surgery and molecular and medical pharmacology at the University of California Los Angeles and a director of the Parker Institute for Cancer Immunotherapy at UCLA

In 2012, R. Stewart Scannell’s doctor informed him that melanoma had spread and he had months to live. “There was no sympathy, no empathy, no nothing,” he said.

Scannell, then 64, didn’t want to give up. He turned up in the office of Dr. Antoni Ribas. The tone was so different, said Scannell, who has flown from Oklahoma City to Los Angeles for treatment every three weeks since, a total of 105 times.

Ribas is a patient favorite not only because of his bedside manner. He has also saved their lives.

For the past 17 years, Ribas, 52, has been at the forefront of a revolution in treating cancer, by turning the patient’s own immune system against it. In 2001, when cancer immunotherapy was mostly dismissed, Ribas began one of the first clinical trials to test it. His first patient to respond is still alive. He later led the clinical development of immunotherapy drug Keytruda.

Ribas, a fourth-generation physician who spends two days a week seeing patients and the rest in his lab, has been studying other ways to manipulate the immune system to fight cancer.

“It’s not the time to slow down,” he said. “It’s time to do more.”

Rhino and future of reproduction

Katsuhiko Hayashi, professor, department of Stem Cell Biology and Medicine, faculty of medical sciences at Kyushu University, Fukuoka, Japan

Katsuhiko Hayashi smiles when he thinks about helping to restore the white rhinoceros. The last male of the species died in March, and the only two females are growing old. But if the reproductive biologist can clear some major hurdles in his lab, he can help bring back the species.

Less than two years ago, his team became the first to grow viable mouse eggs in a lab — and rear baby mice — from skin cells taken from an adult animal’s tail.

The same research could also be a tremendous help to humans, but it’s more ethically fraught. He and his peers are taking slow, methodical steps toward transforming human skin or blood cells into healthy eggs and sperm. If they succeed — likely not for decades — they could cure most infertility.

Hayashi, 46, who once thought he would grow up to run his uncle’s cattle farm, thinks the work should not be tried in people until scientists could be certain that such babies would be just as healthy as those born of more typical eggs and sperm.

While a handful of other scientists are already moving into studying human cells, Hayashi is happy to stick with animals, even if his peers beat him in the scientific race. “Some people are competitive,” he said. “I like peace.”

Building blocks to unlock the brain

Sergiu Pasca, assistant professor of psychiatry and behavioral sciences at Stanford University

Between his thumb and forefinger, Dr. Sergiu Pasca held up a vial of liquid. Inside floated a milky ball of cells — the early stages of an effort to better understand the human brain by building its parts from scratch.

A decade ago, just out of medical school in Romania, Pasca pioneered work transforming skin cells into multipurpose stem cells and then into the type of brain cells found in the cerebral cortex — the thinking area and most distinctly human part of our brains. He has made brain cells from people with autism and schizophrenia, for instance, and is working to understand the ways in which they operate differently.

Scientists used to grow cells in a flat layer on a petri dish, but Pasca discovered that when he and his colleagues allow stem cells to grow in a ball shape and guide them to become brain cells, they begin to self-organize, develop and function more naturally. When Pasca, 36, put two balls resembling different brain regions next to each other, they started to form neural circuits.

Pasca is quick to note that they are worlds away from a true, working brain. But he and colleagues called for s ethical research guidelines in this area. “An ethical framework must be forged now, while brain surrogates remain in the early stages of development,” they said.

Looking to pigs for organ transplants

Luhan Yang, co-founder and chief scientific officer of eGenesis, a startup based in Cambridge, Mass.

Luhan Yang is haunted by one statistic: 20 people die every day in the United States awaiting an organ transplant. “It’s a really heartbreaking situation for the patient, their family and the doctor who wants to do more,” she said.

This knowledge drives her work every day. Yang is trying to make pig organs safe to transplant into people. The shortage would disappear if people could get spare kidneys, lungs and hearts from pigs.

Researchers largely gave up on this idea in the 1990s over concerns pig viruses would spread to humans, and because they couldn’t figure out how to prevent the human body from rejecting organs from another species, Yang said.

But Yang and a few other scientists are renewing interest in the field. She and her colleagues showed last year that they could edit the pig genome in dozens of places simultaneously to remove viruses that might otherwise infect transplant patients. Now, Yang’s team is working to adapt the pig immune system so the organs won’t be rejected when transplanted. And the pig has to be able to survive, despite these genetic changes.

Yang, 32, is mindful that there may be ethical concerns. But, she said, she feels the importance of saving human lives is worth the ethical risk.