In this educational webinar, Dr. Timothy A. Hacker discusses strategies and experimental design of long-term, chronic cardiovascular research in rodents. Specifically, he reviews the use of implantable telemetry, imaging and complimentary technologies for cardiovascular research, highlighting when to adopt one technology versus another and the advantages and limitations of each. He shares best-practices related to data acquisition and analysis, data interpretation and how to prepare data in support of your research hypothesis. Additionally, he touches on fundamental topics relevant to all preclinical cardiovascular experimentation, such as standardization, animal care, the 3Rs and regulatory constraints. Key topics covered during this webinar include… - Why do some translational models correlate poorly with human disease? - Why are chronic models important? - Animal model and rodent strain choice - How to choose the right tools based on your research objectives - How to systematically approach data review and analysis and draw conclusions that support your research hypothesis

1. Dr. Tim Hacker discusses experimental design, strategy,
technology, common challenges and best-practices
associated with planning long-term, chronic models
of cardiovascular disease in rodents.
Experimental Considerations
When Planning Chronic Models of
Cardiovascular Disease in Rodents
#LifeScienceWebinar #ISCxScintica

2. Timothy A. Hacker, PhD
Experimental Considerations
When Planning Chronic Models of
Cardiovascular Disease in Rodents
#LifeScienceWebinar #ISCxScintica
Cardiovascular Physiology
Core Facility
University of Wisconsin-Madison

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6. Experimental Considerations
When Planning Chronic Models of
Cardiovascular Disease in Rodents
Copyright 2018, Timothy A. Hacker and InsideScientific. All Rights Reserved
Timothy A. Hacker, PhD
email: th2@medicine.wisc.edu
Cardiovascular Physiology Core Facility
University of Wisconsin-Madison

7. Key topics covered during this webinar will include…
 Why do certain translational models have a weak correlation with
the human disease? Are there intrinsic problems with the models, or are
scientists making fundamental errors?
 Why are chronic models important? Why choose chronic vs. acute
in vivo procedures
 Animal model and rodent strain choice
 Technology Review: physiologic telemetry vs. imaging vs. non-invasive
techniques
 How to systematically approach data review and analysis

8. Should mimic critical features of human disease…
1. Considerations
• Mimic the course of disease for the duration
• Mimic for a single discrete time point
• Molecular and genetic similarities
2. Limitations
• Lack of diversity
• Lack of co-morbidities
• Differences between species in cell and molecular make-up
What makes a good model?

9. • Leading cause of morbidity and mortality in the US
• Prevalence of associated risk factors such as diabetes, hypertension,
obesity, high cholesterol, inactivity and aging is increasing
Example model – Heart Failure (HF)
• Current treatments only slow the
progression of the syndrome…
(1) Beta blockers (2) Diuretics
• Thus, there is a great need to develop novel
preventative and reparative therapies

10. 1. Clinical Syndrome
• Dyspnea
• Fatigue
• Exercise intolerance
• Retention of fluid in the lungs and/or peripheral tissues
2. Fundamental Defect
• Impaired filling and/or ejection of blood from the heart
What is heart failure?

11. Genetic mutations (cytoskeletal,
sarcolemmal, sarcomeric, nuclear envelope
proteins), MI, longstanding hypertension,
CAD, myocarditis, some chemotherapeutic
drugs, autoimmune disorders, excessive
tachycardia, endocrine disorders, excessive
alcohol consumption, nutritional
deficiencies, neuromuscular disorders
Causes of Heart Failure

12. Hemodynamics
Critical Similarities of All Types of Heart Failure
• decreased systolic & diastolic function
• diminished contractile reserve
(catecholamine stress)
• increased wall stress
• depressed isovolumic ejection phase
• slowed relaxation rate
• depression of stretch induced force
response
• blunting of force frequency response
• altered Ca uptake storage and release
• altered beta adrenergic receptor
function

13. • MCT
• SUGEN/Hypoxia
• Isoproterenol
• DOCA
• Transgenic
• Knockout
• Salt sensitive
• Diabetic
• High Fat
• Permanent
ligation
• Ischemia/
Reperfusion
• Aortic
Regurgitation
• Fistula
• Aortic banding
(TAC)
• Pulmonary
Arterial Banding
Rodent Models of Heart Failure
Pressure Overload
Genetic Models
Drug Induced
Volume Overload
Myocardial
Infarction
Aging & Metabolic

14. Structural Changes
• Ventricular dilation
• Normal or reduced wall thickness
(eccentric hypertrophy)
• Biventricular and biatrial enlargement
• AV valve regurgitation
• Increases in organ
and chamber weight
• Myocyte hypertrophy
Functional Changes
• Systolic/diastolic dysfunction
• Abnormalities of diastolic filling
• Increased diastolic and systolic wall stress
• Elevation of left and right sided filling pressures
• Activation of neurohormonal systems
• ECG
Heart Failure: Measurable Parameters

15. What Do You Need
To Measure?
1. Structure
• Echo
• MRI, CT, PET, Angiography

16. 1. Structure
• Echo
• MRI, CT, PET, Angiography
2. Function
• Pressure
• Pressure – Volume
• Doppler Flow Velocity
• mitral and aortic valve
• Ultrasound (2,3 and 4 D, strain)
• MRI, CT, Angiography
• ECG
• Ultrasonic Crystals
Mitral Inflow
Aortic
Outflow
ECG
Some Aortic Outflow Measurements:
• Heart rate
• Ejection time
• Peak/mean velocity
• Peak/mean acceleration
• Stroke distance
Some Mitral Inflow Measurements:
• E & A peak velocity
• E/A ratio
• Isovolumic contraction time
• Isovolumic relaxation time
What Do You Need
To Measure?

17. Acutely
• Non-invasively
• Invasively
Chronically
• Implantable
How will you measure it?
Learn more about equipment for functional
cardiovascular measurements at
www.scintica.com

18. Measurements
Acute
Advantages
- Lower Cost
- Fast
- Some measures can only be
done acutely
Disadvantages
- Under anesthesia
- Some are terminal
Chronic
Advantages
- Awake
- Fewer Animals
- Normal Behavior
- Diurnal measures
- Continuous
- Less stress
Disadvantages
- Higher initial
cost for some
Snap shot vs. Movie!

19. 0
20
40
60
80
100
120
140
160
acute Chronic- awake Chronic- asleep
Acute vs Chronic
WT TG male TG female TG treated
*
* *
*
#
#
# #
Acute studies
(under anesthesia) n = 7-8
(no significant difference between treatments)
Chronic-awake
(awake, freely moving mice n = 4)
Chronic-asleep
(sleeping mouse, no anesthesia n =4)
Columns with different superscripts
are different at p<0.01
Acute vs. Chronic Blood Pressure

20. Cav1.2 Disruption
Decreases Heart
Rate and Increases
PR Interval
Advantage of chronic ECG measurements over time

21. 1. Disease model
2. Standardization = to make uniform
• Standardization of the model
• Standardization of staff
• Standardization of instrumentation
• Stratification
3. Calibration = checking against known standards
• Calibration of the model
• Calibration of staff
• Calibration of instrumentation
Fundamental considerations for successful experimental design/planning

22. 1. Disease model
2. Standardization = to make uniform
• Standardization of the model
• Standardization of staff
• Standardization of instrumentation
• Stratification
3. Calibration = checking against known standards
• Calibration of the model
• Calibration of staff
• Calibration of instrumentation
Fundamental considerations for successful experimental design/planning
4. Animals
• Strain (This is critical!)
– Transgenic colonies can drift over
time
– How many back crosses?
– What is your source of the animals?
• Sex
• Blinding/Randomization
• Proper controls
(negative and positive)
• Numbers (power calculations)

23. How long after implant should you wait before recording data?
 When and how long should you record
– 24 hour recordings
– Batch recordings
– Time of day
– Post treatment
 Common errors / pitfalls / limitations
– Cage changes
– Light/dark cycles
– Vibration/construction
– Temperature/humidity
– Other animals/proximately to males/females
AO pressure implants
0
50
100
150
2 3 5 7 8 9
Days Post Implant
AOpressure(mmHg)
Systolic BP
Heart Rate
0
100
200
300
400
500
600
2 3 5 7 8
Days Post Implant
Beats/min
Telemetry Data

24. How does it compare to…
• Literature
• Previous experiments
• Animals within the group
• Gold standard
• Histology/organ weight
Data Interpretation & Validation

25. • Functional measurements should include
any parameters that might alter function
 HEART RATE
 Time of day
 Time post intervention
• How many animals did you start with?
How many are included in the analysis?
• Structural analysis should include
images and histology
Presenting data for review

26. No one model will be perfect!
 Careful experimental design
 Choose your models carefully
 Use multiple animal models,
use co-morbidities, aged animals
Carotid Artery

27. Thank You
For additional information on the products and applications presented during
this webinar please visit www.scintica.com
Timothy A. Hacker, PhD
email: th2@medicine.wisc.edu
Cardiovascular Physiology Core Facility
University of Wisconsin-Madison