Human bone grafts can be complicated. In the early days, they typically involved two surgeries, the first to remove bone from part of the body and the second to graft that bone onto another part of the body. For decades, scientists have been working to simplify the process by using artificial bone in place of real bone. Coral, which closely resembles human bone in structure, has been among the most promising substitutes.
Unfortunately, coral skeletons are made of calcium carbonite, which breaks down in the human body before new bone can grow on it, so it can’t be used as is. While researchers have developed a variation of coral that doesn’t degrade as quickly once grafted, challenges remain.
Scientists want to learn more about how coral skeletons form so they might improve the process of using coral in human bone grafts, since human bone and coral skeletons are structurally similar. Their findings also could bring scientists closer to finding new approaches for healing human fractures, and for treating deeper skeletal and spinal problems. In addition, such insights also could help safeguard coral reefs, which have coming under increasing threat from rising ocean temperatures, pollutants, ocean acidification and rising seas.
“Processes as complex as constructing a skeleton must be conceived and initiated at the earliest stages of life,” said Gil Goobes, a chemistry professor at Bar-Ilan University, one of a team of Israeli scientists believed to be the first to pinpoint the stage when a young coral shifts from the swimming phase to the settled phase, when it forms a skeleton.
Moreover, they were able to identify the specific proteins generated at each phase of the process, offering insight into the maturation of coral skeletons, a process known as mineralization. “It’s like the construction of a successful skyscraper. If you want to be able to build one, you need to understand many things and on very different levels,” Goobes said.
Understanding this process can improve “our ability to predict the impact of climate changes on coral demographics and community structure,” said Tali Mass, a scientist at the Leon H. Charney School of Marine Sciences at the University of Haifa and a member of the research team. “Coral reefs are being degraded worldwide. As with other invertebrate species, coral larval development is more sensitive to the environment changes as compared to adults.” She added, “Our research may help supply the needs for corals at their infancy, so they can increase the chances of their survival and longevity in the changing conditions in the oceans.”
Goobes agreed. “Just like our ability to nurture newborns with the necessary needs for development, understanding the mineralization processes and how they are harmed by temperature change or ocean acidification can allow us to supplement the corals with molecules they need to overcome these variations,” he said. In addition to Goobes and Mass, the team also included Anat Akiva and Dr. Iddo Pinkas, both of the Weizmann Institute of Science in Israel. Their study appears in the journal Nature Communications.
Their findings could also improve coral-based bone grafting, Goobes said. He compared grafting to fixing a car. “We can ‘implant’ an engine from one car, say some race car, into the body of another car, say a Volkswagen beetle, and we will be mostly successful,” he said. “However, knowing the details of how each of the engines works… will allow us to avoid problems of incompatibility. In the short run, yes, the car will run and probably achieve its task, but there will be long term issues which will shorten its lifespan.
“The same can be said for bone replacements, where there also can be undesired side effects,” Goobes added. “Understanding the details of the mineralization process on a fundamental level is like knowing exactly what each part in the engine does, and what needs to be put in to make work exactly right.”
Corals start life as plankton polyp which swim freely in the sea. Eventually, the polyp settles and skeleton formation begins. During this time, the polyp secretes calcium carbonate very rapidly in order to form and protect the reef colony; proper development of polyps to the settled stage is crucial for the proper development of coral reefs, according to the researchers.
“During coral spawning season in the Red Sea, we collected newborn swimming individuals — planula — using special nets and took them to the lab for examination and continued growth and development,” Goobes explained. The scientists placed the corals in seawater in a petri dish, recreating the same conditions they would find in the sea. They then studied them at different stages of development, analyzing the process of skeleton production.
Scientists also studied gene expression during both the swimming and settled phases. “The immediate significance of these findings is in understanding the process of coral reef formation,” Goobes said, noting that the information could prove valuable “in conserving marine creatures from the ecological damage associated with climate change.”
Goobe added, “In this study we have discovered how skeletal growth can be regulated,” in corals, a finding that “will advance the development of new, bio-technological techniques for bone transplants in the human body. Although we are a long way from understanding the mechanism by which humans form a skeleton, the present study is an important step in identifying the genes and proteins responsible for this process.”
Protecting corals from climate change could save lives.Marlene Cimons writes for Nexus Media, a syndicated newswire covering climate, energy, policy, art and culture.