PhD student mentored by Genco continues work on disease links between mouth, gut

When Jiho Sohn begins his practice as a doctor specializing in gastrointestinal disorders, he will continue the legacy of research and service practiced by the late Robert J. Genco, SUNY Distinguished Professor of oral biology, periodontics and microbiology.

“Dr. Genco was the main reason I came to UB’s MD-PhD program,” says Sohn, who will graduate in April. Sohn was lead author of “Periodontal disease is associated with increased gut colonization of pathogenic Haemophilus parainfluenzae in patients with Crohn’s disease,” which appeared in Cell Reports in February. The paper described collaborative research begun by Sohn and Genco. Several other researchers co-authored the article.

“When I first met Dr. Genco,” Sohn says, “I expected a brief meeting, maybe 30 minutes. But we clicked instantly, and we talked for an hour and a half.” The two shared in interest in microbiomes: Sohn was interested in the intestinal microbiome (the community of microorganisms that live in the intestines); Genco was interested in the oral microbiome. In fact, Genco was named the “father of oral science” in the Journal of Dental Research for his influential role in demonstrating the connection between the oral microbiome and overall health, including diseases such as diabetes and heart disease.

Despite his international renown as a groundbreaking researcher, Genco was very much a hands-on mentor to many PhD students, including Sohn. Sohn came to study at UB in 2015, the year before UB established the Center for Microbiome Research with Genco as its director.

“Dr. Genco’s enthusiasm made him an exceptional mentor,” Sohn explains. “Once you start your PhD research, you become very specialized, and very few people share your excitement. We were both really excited about the direction our research was taking.”

The recent paper examines a connection between a bacterium, Haemophilus parainfluenzae, found in both the oral and intestinal biomes. Its presence in the mouth generally indicates health, but its presence in the intestinal microbiome is linked with inflammatory bowel diseases, including Crohn’s disease. Sohn conducted genomic analysis of H. parainfluenzae that revealed the existence of multiple strains of the bacterium. This led to further research and the suggestion that one particular strain may be responsible for increased inflammation in the colon. Additional findings lay the groundwork for further research into possible links between periodontal disease and inflammatory bowel diseases.

One Wednesday in March 2019, Genco met with students to discuss the work they had done in the lab earlier that morning. As the meeting ended, Genco stood, only to fall suddenly. Sohn attempted to revive Genco with CPR, but without success. “It was very difficult for all of us,” Sohn recalls. “Very sad.”

The research, which involved patients with Crohn’s disease, was at risk of being disrupted. Keith Kirkwood, now senior associate dean for research, as well as professor of oral biology who holds the dental school’s Centennial Endowed Chair, stepped in to ensure that Sohn’s research — and Genco’s — could continue. “Dr. Genco was my mentor, too, when I was a PhD student here,” Kirkwood notes. “Dr. Genco was influential in so many ways, and he was focused on improving people’s lives through his research and entrepreneurship. Sohn’s work is part of Dr. Genco’s legacy.”

Genco’s 51-year career at UB included research that has transformed the practice of dentistry. He was also named a fellow of the National Academy of Inventors posthumously; the NAI fellows program recognizes academic inventors whose inventions have made a tangible positive impact on quality of life. But perhaps Genco’s greatest legacy will be the many students who will continue his work thanks to the encouragement and inspiration he gave so generously.