The John B. Pierce Laboratory


Dr. Usselman’s published work chosen as an APSselect Paper

Charlotte Usselman, PhD has been a Post Doctoral Fellow in Dr. Nina Stachenfeld’s laboratory since November, 2015.  Before coming to the Pierce Laboratory, Dr. Usselman trained in Kevin Shoemaker’s laboratory at Western University (Canada), one of the most prestigious laboratories in the world studying neurovascular control of blood pressure.  A paper recently published from her work in that laboratory, Hormone phase influences sympathetic responses to high levels of lower body negative pressure in young healthy women was recently published in Am J Physi – Reg, Integrative Comp Physiol (  This paper was chosen by the Journal as an APSselect Paper.

APSselect: The editorial team carefully selects from the top articles nominated each month across the 10 APS (American Physiological Society) research journals that highlight, promote, and rapidly disseminate some of the most stimulating original research.  This is a rare and exciting honor, especially for a scientist in the early phase of what is obviously a promising career in physiology.

This study examined the role that circulating sex hormones play on maintaining blood pressure during orthostatic challenges.  Orthostatic challenges are those which encourage the pooling of blood in the lower body, such as standing for a long time, or moving from seating or lying to standing.  Usselman et al. found that high female sex hormone conditions were associated with greater peripheral blood pooling, likely the result of estrogen as a dilator of peripheral blood vessels. One unexpected finding was that women taking hormonal contraceptives experienced a fall in blood pressure at the highest level of lower body negative pressure, implying that hormone exposure may reduce orthostatic tolerance in young women. Together, these data improve our understanding of the role of sex hormones on the regulation of blood pressure, and provide some insight into the mechanisms by which young women have an increased risk for orthostatic intolerance but are protected from hypertension.

Research Scientists develop model for studying Alzheimer’s disease

By Ziba Kashef

The vast majority of Alzheimer’s disease cases are not directly inherited but linked to environmental and genetic factors. Yet most models used for studying Alzheimer’s in animals mimic the inherited form of the disease.

Yale researchers developed a novel model that may prove useful to the study of Alzheimer’s at its earliest stages. Led by associate professor of neuroscience Justus Verhagen of The John B. Pierce Laboratory and research scientist Alla Ivanova, the researchers studied mice lacking a protein, Fus1, that helps regulate mitochondria — the structures that maintain the balance of critical functions within cells.

In tests, these animals exhibited a loss of smell as well as spatial memory — early signs of Alzheimer’s in people. If confirmed in further studies, the model could serve as an additional tool for understanding the role of Fus1 and mitochondria in the development of Alzheimer’s, said the researchers.

Read the full study published in Frontiers in Aging Neuroscience.

Drs. Stachenfeld and Usselman receive the Paul E. Titus Fellowship in Obstetrics for 2016-2017

Drs. Nina Stachenfeld and Charlotte Usselman are recipients of the Paul E. Titus Fellowship in Obstetrics at Yale School of Medicine for 2016-2017.  This fund supports research into adverse pregnancy outcomes.  Preeclampsia affects ~5% of pregnancies, and is the leading cause of maternal-fetal morbidity and mortality world wide, including the United States.  The cardiovascular consequences of preeclampsia are particularly severe, and include hypertension and proteinuria.  Our ability to predict, prevent or cure preeclampsia (short of complete bed rest or delivery) is limited.  Drs. Stachenfeld and Usselman’s project, “Acute Cardiovascular Stressors to Determine Preeclampsia Risk” examines a number of measures targeting endothelial and sympathetic nervous system function in previously preeclamptic women as well as control participants.  These measures will uncover indicators of cardiovascular dysfunction that are unique to women who have a demonstrated increased risk for preeclampsia.  In the proposed study Stachenfeld and Usselman will, for the first time, test a range of cardiovascular stressors that activate different reflex loops known to be involved with preeclampsia. In doing so, the elucidation of novel but simple screening methods for preeclampsia will, in turn, lead to methods which will allow for preventative therapies, early detection, and/or targeted interventions for women with preeclampsia.