Karen R. Gaar-Humphreys

Ms. Karen R. Gaar-Humphreys

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
29 June 2022 in Animals
Verified
Journal Article
Open access
PDF file
KGKaren R. Gaar-Humphreys
Karen R. Gaar-Humphreys
TSTalitha C. F. Spanjersberg
Talitha C. F. Spanjersberg
GSGiorgia Santarelli
Giorgia Santarelli
GGGuy Grinwis
Guy Grinwis
Viktor SzatmáriViktor Szatmári
Viktor Szatmári
FSFrank G. van Steenbeek
Frank G. van Steenbeek
Cardiac disease is a leading cause of death for both humans and dogs. Genetic cardiomyopathies, including dilated cardiomyopathy (DCM), account for a proportion of these cases in both species. Patients may suffer from ventricular enlargement and systolic dysfunction resulting in congestive heart failure and ventricular arrhythmias with high risk for sudden cardiac death. Although canine DCM has similar disease progression and subtypes as in humans, only a few candidate genes have been found to be associated with DCM while the genetic background of human DCM has been more thoroughly studied. Additionally, experimental disease models using induced pluripotent stem cells have been widely adopted in the study of human genetic cardiomyopathy but have not yet been fully adapted for the in-depth study of canine genetic cardiomyopathies. The clinical presentation of DCM is extremely heterogeneous for both species with differences occurring based on sex predisposition, age of onset, and the rate of disease progression. Both genetic predisposition and environmental factors play a role in disease development which are identical in dogs and humans in contrast to other experimental animals. Interestingly, different dog breeds have been shown to develop distinct DCM phenotypes, and this presents a unique opportunity for modeling as there are multiple breed-specific models for DCM with less genetic variance than human DCM. A better understanding of DCM in dogs has the potential for improved selection for breeding and could lead to better overall care and treatment for human and canine DCM patients. At the same time, progress in research made for human DCM can have a positive impact on the care given to dogs affected by DCM. Therefore, this review will analyze the feasibility of canines as a naturally occurring bidirectional disease model for DCM in both species. The histopathology of the myocardium in canine DCM will be evaluated in three different breeds compared to control tissue, and the known genetics that contributes to both canine and human DCM will be summarized. Lastly, the prospect of canine iPSCs as a novel method to uncover the contributions of genetic variants to the pathogenesis of canine DCM will be introduced along with the applications for disease modeling and treatment.

30 October 2025 in Stem Cell Research
Verified
Journal Article
Open access
KGKaren R. Gaar-Humphreys
Karen R. Gaar-Humphreys
VBValentina Balducci
Valentina Balducci
FPFemke Pol
Femke Pol
EVElizabeth Vafiadaki
Elizabeth Vafiadaki
AAAris Anastasakis
Aris Anastasakis
Francesca StillitanoFrancesca Stillitano
Francesca Stillitano
Phospholamban (PLN) cardiomyopathy, caused by the deletion of arginine 14 in PLN (PLN-R14del), is associated with both dilated and arrhythmogenic cardiomyopathy, often manifesting early in life. Interestingly, some carriers remain asymptomatic with a normal life span. The mechanisms underlying disease progression remain unclear. We generated human induced pluripotent stem cell (iPSC) lines from peripheral blood mononuclear cells of two asymptomatic Greek PLN-R14del carriers and one non-carrier relative. These iPSC lines exhibit typical morphology and markers of undifferentiated hPSC state, providing an in vitro platform to investigate disease mechanisms and gain insights into the patient-specific onset and progression of PLN-R14del cardiomyopathy.