Understanding Our Limits

Gerardo Bosco applies modern technologies in hyperbaric research.

Bosco takes readings at the entrance of a chamber.

An extraordinarily ambitious researcher and physician, Dr. Gerardo Bosco has worked with universities and health-care systems across the globe for more than two decades and is a fixture in the international biomedical science and hyperbaric medicine communities. With a medical degree from Università degli studi G.D'Annunzio Chieti Pescara and a doctorate in muscle pathophysiology from State University of New York (SUNY) Upstate Medical University, he has served several residencies in dive medicine, hyperbaric medicine and nutrition sciences. He is a visiting professor at the University of Greifswald, SUNY Upstate Medical University and the University of South Florida and an assistant professor in hyperbaric medicine at the University of Padova.

An international faculty member at the Duke Center For Hyperbaric Medicine and Environmental Physiology and former vice president of the Undersea and Hyperbaric Medical Society (UHMS), Bosco has expertise in nutrition science, muscle pathophysiology and wound care but is best known for his clinical hyperbaric research, having authored more than 100 scientific publications in national and international journals. He has the unique opportunity to push the limits of our understanding with his research, support the field in its entirety and cultivate new research across the globe.

How did you first start diving, and how has your diving progressed over the years?
I started diving relatively late in life, when I was a 23-year-old medical student. I played sports throughout my childhood but was never able to dive. While looking for an ancient submerged city under the tutelage of Professor Piergiorgio Data (a physiologist, cardiologist and the director of what was the only residency in diving and hyperbaric medicine in Italy at the time), I was finally afforded the opportunity to learn how to dive. From that experience, I became drawn to the sport and the science and began studying in his physiology program. My first project was cleaning out and painting an office for myself, but he quickly involved me in all the ongoing experiments. My research has frequently given me opportunities to advance my diving.

It sounds like your diving has been closely related to your research. How did your research progress from the projects you worked on during your physiology program?
My first real projects with Data involved isolating carotid arteries in rats using contrast medium for postdive pulmonary scintigraphy. The goal was to use the rat model to learn more about how the human body responded to the rigors of the dive environment. From there I became involved in respiratory and metabolic research, and my personal scientific toy became a portable metabolimeter for measuring oxygen consumption.

Throughout this research my interest in diving continued, driven by stories of freedivers Jacques Mayol and Enzo Maiorca as well as the great scientific expeditions

Bosco studies postimmersion platelet activation in Monte Bianco.
Data directed in Peru, Indonesia and Greece. Through these stories I became intrigued by environmental physiology. In 1996 I participated in a training course by the European Space Agency (ESA) under the supervision of Franco Rossitto. Following that course, Rossitto, Data and I began working on some fascinating research using hyperbaric chambers for treatment of asbestos burns, giving me my first real experience with a hyperbaric chamber. In these early days, the experimental protocol was a bit extreme, and we would work only at night — when the lab building was empty — for the safety of our colleagues.

My work from this point onward focused on applying technology to human physiology. It included research into oxygen consumption among combat, breath-hold and scuba divers at extreme altitude as well as the evaluation of postimmersion platelet activation in an ice-covered lake in Monte Bianco. This work eventually came full circle and brought me back to my initial research in physiology, working on the ischemia-reperfusion model and human metabolism in extreme environments at SUNY Upstate.

Your research background is both uniquely broad and easily relatable to the dive community. Much of the research in dive medicine focuses on finding a cause for a known mechanism rather than discovering something unknown. Has any of your research resulted in a particularly surprising outcome?
Most of the results of my research are unexpected. The work that really interests me involves uncovering the unknown in the human body, particularly in extreme environments, so unknown results come with the territory. Right now my main goal is to clarify the link between oxidative states, production of reactive oxygen species (ROS) — a normal product of cellular metabolism — and inflammatory markers in divers. In pursuit of this goal, my colleagues and I have been doing a significant amount of work with the mechanism of action of hyperbaric oxygen (HBO) in patients with osteonecrosis and the mechanism of HBO preconditioning for divers. By understanding the ways that these mechanisms affect patients, we hope to understand more about how divers' bodies respond to their environment.

What about research that goes the other direction? Does your work in dive medicine ever result in clinical implications or discoveries?
It does! I was involved in a recent study that focused on femoral head necrosis — a condition that can result from certain types of extreme diving, typically at great depth and for long periods — that suggested some interesting results. We found that the effect of HBO on production of osteoprotegerin (OPG), a type of cytokine receptor, suggests that HBO may be able to stimulate new bone formation. I strongly believe that this angiogenesis capacity stimulated by HBO could lead to new insights and clinical indications for HBO.

Ketogenic diets have drawn increased focus in both fitness and dive medicine research lately. Do you have any insights into the concept?
It is true that research on the ketogenic diet is increasing in visibility and bringing credibility to the method for treatment of some metabolic and neurologic disorders. We know that the short- and medium-term effects of this diet regimen appear safe and effective to lose weight, decrease cardiovascular risk and reduce the risk for oxygen toxicity in divers. We still do not know the long-term effects of this diet. While it may have merit for divers, I would not expect as big a benefit in divers as some experimental studies have shown.

The Y-40 Deep Joy in Padova, Italy — the world’s deepest swimming pool
What current and future research advancements can we expect from you or your colleagues?
Many ongoing research projects in the field of physiology could affect the way we dive. This research takes time to change the reality of the sport, but the safety benefits can be great. To date, oxygen pretreatment has shown some of the most promise in new research. Military and aerospace activity will see the most benefit from these methods of oxygen administration before exposures (whether they be underwater or in space). With the recent increases in the popularity of technical diving, however, I think this work could be important for the safety of many, if not all, divers.

Some of our other recent work has focused on clarifying the psychophysiological aspects of diving and open-ocean survival to help sea-rescue services and taking arterial blood gas measurements at 40 meters of depth in breath-hold divers. This last project was uniquely challenging, but it resulted in the first real attempt at getting numbers for the partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), acidity (pH) and lactate in divers in the water.

My goal, and the goal of the research teams I work with, is to respect the traditions of our sport but create new perspectives using modern technologies. Our aim is to verify how to strengthen endurance performances, understand how the human body responds to the exposures to which we subject it and improve the safety of humans in all conditions.

© Alert Diver — Q4 Fall 2018