Exploring Day/Night Patterns in Personal Exposure to Air Pollutants: Asthma and the Human Clock
Residing in Queen Village, a neighborhood in Philadelphia, PA, Dr. Skarke is witnessing how nocturnal asthma —breathing problems typically occurring between 3:00 to 5:00 AM —is taking a toll on some families and their children. The risk to be affected by asthma is much higher in the City of Philadelphia than in other communities of the nation. The Pennsylvania Department of Health reports for 2013, that about 22% of children are asthmatics in Philadelphia versus less than 10% nationwide (National Health Interview Survey, CDC, 2016). For many children and adults, symptom-free days alternate with episodes of asthma, often at night, and missed school or work days, even hospital visits.
Now, in his CEET research project “Air Pollution, Asthma and Circadian Clocks,” Dr. Skarke seeks to collect data to help understand the day/night pattern (circadian), between air pollutants, such as ozone or particulate matter, and asthma. Given that different areas of the city probably have different time courses of personal exposure to air pollutants, Dr. Skarke deploys wearable sensors to measure hyperlocal concentrations of air pollutants. These data at high resolution should allow him and his team to identify temporal associations between exposure and onset of disease symptoms. Understanding these relationships might offer insights which could help predict the next asthma episode. Studies under lab conditions showed, for example, how certain microRNAs, small molecules which fine-tune gene expression, are upregulated in asthmatics as well as after experimental exposure to ozone. Many of these microRNAs are associated with inflammation and circadian control. Future studies might use these microRNAs to shed more light on underlying mechanisms.
“Of course, this is a long way to go. First, we need to start small, field-testing the devices in healthy volunteers and learning how to collect and interpret data, before we ask asthma patients to enroll in our studies. Then we can start looking for mechanisms,” says Dr. Skarke.
This line of work represents a strong new focus for Dr. Skarke’s research. Fostered by Penn’s growing Chronobiology Program, Dr. Skarke incorporates time in his research to elucidate the role of biorhythms (and their disruption) in health and disease. Dr. Skarke studied circadian rhythms in volunteers to begin defining the Human Chronobiome — a collection of a person’s physiological traits over a 24-hour timeframe in the natural settings of a volunteer’s personal lifestyle. “This is a necessary endeavor to understand how the physiology in healthy individuals varies hour-by-hour,” underscores Dr. Skarke. Using this knowledge, the expectation is to better understand which changes in the chronobiome associate with certain diseases.
“I am very excited to launch into this intersection of medicine and environment,” remarks Dr. Skarke. He grew up most of his childhood in Zornheim, Germany, a village of about 3,000 people which is defined by its vineyards and its open space. The growing environmental movement in Germany acted as a driving force for his scientific curiosity, and he took a strong interest in pursuing environmental sciences.
Through Germany’s conscription laws to military or civilian service, Carsten had the unique opportunity to complete his civil service as a paramedic, which put him in close contact with professionals in the medical field. After a year of responding to cardiovascular and respiratory emergencies, Dr. Skarke knew he wanted to go into medicine. He earned his MD (Medicine) from the Johannes Gutenberg University School of Medicine in Mainz, Germany, 1998, with a doctorate (Dr. med.) awarded in 2000.
Dr. Skarke continues, “I went to medical school driven by my experiences as a paramedic. I was pretty much set on doing internal medicine. However, my doctoral thesis work sparked my interest in research.” As a trained MD, Dr. Skarke sought out translational research as a domain with direct impact on understanding and treating disease conditions. This interest led
Dr. Skarke to join the Penn community as an Alexander von Humboldt-Fellow in 2007, followed by his faculty appointment in 2010.