Telomere Health and ICU Outcomes

Faculty study awarded Research Impact Grant

Patients who survive the intensive care unit (ICU) have disproportionately higher morbidity than other hospitalized groups. Nearly 70 percent experience declines in physical and/or cognitive function, and almost all experience symptoms of anxiety and depressed mood.

Faculty from the School of Nursing and Health Studies wondered whether some of those declines and mood changes might be related to telomere shortening or damage. Co-investigators Charles Downs, associate professor, and Zhan Liang, assistant professor, will study this question through a new Impact Research Grant from the American Association of Critical-Care Nurses (AACN).

Telomeres are the “caps” at the ends of each DNA strand that protect the DNA. Damage, or shortening, of telomeres is linked to aging and a variety of disease processes. Downs and Liang specifically wondered whether critical illness causes oxidative stress (an imbalance of oxidants and antioxidants) that accelerates telomere attrition, ultimately affecting physical, cognitive and psychological outcomes among ICU survivors.

Studies have already established that critically ill patients experience inflammation and elevated energy expenditure (hypermetabolism) while in a resting state, both of which may lead to oxidative stress and have the potential to damage telomeres; increased inflammation is also associated with shorter telomeres.

Previous studies have reported measurable telomere attrition as early as three days after ICU admission. Research has also shown that telomere length controls immune senescence (the aging of the immune system and ability of immune cells to replicate). But what previous studies have not evaluated is the relationship between ICU and post-ICU-related morbidities and telomere length or senescence.

In their study, Downs and Liang will examine the relationship between telomere length, telomere-induced senescence, and ICU-related outcomes; the relationship between telomere length, telomere-induced senescence and physical, cognitive, and psychological outcomes among ICU survivors; and the extent to which oxidative stress moderates these relationships.

Downs and Liang’s team will recruit mechanically ventilated patients who are newly admitted to ICUs at University of Miami Hospital and Clinics. They will then measure telomere length, oxidative stress, and other illness factors, as well as patients’ post-ICU handgrip, foot strength, participation in activities of daily living (ADL), memory, attention, executive function, anxiety, and depressed mood.

Study co-investigators are Arsham Alamian, SONHS associate dean for health studies, and Tanira Ferreira, assistant professor of medicine and director of inpatient services for UHealth.