Blood Flow in Individuals With Down Syndrome

July 11, 2019 updated by: Thessa Hilgenkamp, University of Illinois at Chicago

Central & Peripheral Blood Flow Regulations in Individuals With Down Syndrome

This study focuses on physiological explanations of difficulties with physical activity and exercise in individuals with Down syndrome, by non-invasively examining cardiac output and the regulation of blood flow to working muscles during exercise.

Study Overview

Status

Terminated

Conditions

Detailed Description

Work capacity is an important predictor of declining health or physical function, and of mortality, and is commonly measured as peak oxygen consumption. Peak oxygen consumption is very low in individuals with Down syndrome, the most prevalent genetic cause of intellectual disability. Previous research suggests individuals with Down syndrome may experience a double disadvantage when they are exercising: they may not be able to increase cardiac output sufficiently and they may not be able to allocate adequate blood flow to the working muscles.

The aim of this research study is therefore to determine the impact of limitations in central and peripheral regulation of blood flow on work capacity in individuals with DS. The results of this project will aid our understanding of the underlying mechanisms and determine the potential to improve health across the lifespan of individuals with Down syndrome by tailoring exercise interventions.

Study Type

Interventional

Enrollment (Actual)

21

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Illinois
      • Chicago, Illinois, United States, 60608
        • Disability, Health, and Social Policy Building, Integrative Physiology Laboratory, Suite 158 at 1640 W. Roosevelt Rd

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 45 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Between 18 and 45 years old
  • generally healthy
  • sedentary or low-active (defined as being involved in less than 30 minutes of moderately-intense physical activity per day)
  • additionally for the participants with Down syndrome:

    • diagnosis of Down syndrome trisomy 21 and
    • normal thyroid function or stable thyroid function (and medications) for at least 6 months.

Exclusion Criteria:

  • atherosclerotic or other vascular disease;
  • asthma or other pulmonary disease;
  • hypertension (defined BP >140/90 mmHg);
  • blood pressure below 90/60 mmHg;
  • history of pre-syncope or syncope;
  • diabetes (defined as Hba1c of >7.5% or use of glucose lowering medication);
  • severe obesity (defined as BMI >40);
  • medications affecting heart rate, blood pressure or arterial function;
  • anti-inflammatory medication including NSAIDS;
  • current smoking and
  • pregnancy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Screening
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Individuals with Down syndrome
For participants with Down syndrome, the first visit includes baseline measures and familiarization with the graded maximal exercise test protocol. If necessary, additional familiarization sessions will be scheduled for people with Down syndrome. The second visit, we perform the graded maximal exercise test and familiarize the participant with the procedures for the third visit: the hand grip exercise protocol and the lower body negative pressure (LBNP) box. The third visit we assess the peripheral blood flow during the hand grip exercise protocol without and with the LBNP. For control subjects, the first and second visit are combined. Their second visit is the same as the third visit for individuals with Down syndrome.
For participants with Down syndrome, the first visit includes baseline measures and familiarization with the graded maximal exercise test protocol. If necessary, additional familiarization sessions will be scheduled for people with Down syndrome. The second visit, we perform the graded maximal exercise test and familiarize the participant with the procedures for the third visit: the hand grip exercise protocol and the lower body negative pressure (LBNP) box. The third visit we assess the peripheral blood flow during the hand grip exercise protocol without and with the LBNP. For control subjects, the first and second visit are combined. Their second visit is the same as the third visit for individuals with Down syndrome.
Other: Individuals without Down syndrome
For participants with Down syndrome, the first visit includes baseline measures and familiarization with the graded maximal exercise test protocol. The second visit, we perform the graded maximal exercise test and familiarize the participant with the procedures for the third visit: the hand grip exercise protocol and the lower body negative pressure (LBNP) box. The third visit we assess the peripheral blood flow during the hand grip exercise protocol without and with the LBNP. For control subjects, the first and second visit are combined. Their second visit is the same as the third visit for individuals with Down syndrome.
For participants with Down syndrome, the first visit includes baseline measures and familiarization with the graded maximal exercise test protocol. If necessary, additional familiarization sessions will be scheduled for people with Down syndrome. The second visit, we perform the graded maximal exercise test and familiarize the participant with the procedures for the third visit: the hand grip exercise protocol and the lower body negative pressure (LBNP) box. The third visit we assess the peripheral blood flow during the hand grip exercise protocol without and with the LBNP. For control subjects, the first and second visit are combined. Their second visit is the same as the third visit for individuals with Down syndrome.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Brachial blood flow
Time Frame: In minute 4 of the 5-minute bout of grip strength exercise
Forearm blood flow and vascular conductance will be measured in both the exercising and non-exercising arm using high definition ultrasound (Alpha 7, Aloka-Hitachi). The brachial artery will be imaged in dual mode allowing for simultaneous determination of artery diameter (B-mode) and flow velocity (Doppler mode). Blood flow will be determined from the following formula: Forearm Blood flow = (Mean blood velocity) x (Brachial Cross Sectional Area) x (60) and expressed as ml/min. Forearm vascular conductance will be determined by dividing forearm blood flow by mean arterial pressure. Forearm blood flow and vascular conductance will be normalized to forearm lean mass to account for differences in lean mass between individuals.
In minute 4 of the 5-minute bout of grip strength exercise

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Muscle oxygenation
Time Frame: In minute 4 of the 5-minute bout of grip strength exercise
Muscle oxygenation will be measured with near-infrared spectography (NIRS), which is a simple, noninvasive method for measuring the presence of oxygen in muscle. It can monitor changes in muscle oxygenation and blood flow during submaximal and maximal exercise. During exercise, the extent to which skeletal muscles deoxygenate varies according to the type of muscle, type of exercise and blood flow response.
In minute 4 of the 5-minute bout of grip strength exercise
Cardiac outut
Time Frame: Every second minute until the 12th minute of the maximal test.
Cardiac output will be measured during a graded maximal test protocol using ultrasonography, by measuring the aortic diameter at the level of the valve form the peristernal long axis. Ascending aortic blood flow will be measured using continuous Doppler echocardiography using a pedoff probe in the suprasternal notch.
Every second minute until the 12th minute of the maximal test.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Thessa Hilgenkamp, PhD, University of Illinois at Chicago

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 1, 2018

Primary Completion (Actual)

May 8, 2019

Study Completion (Actual)

May 8, 2019

Study Registration Dates

First Submitted

June 21, 2018

First Submitted That Met QC Criteria

July 6, 2018

First Posted (Actual)

July 18, 2018

Study Record Updates

Last Update Posted (Actual)

July 15, 2019

Last Update Submitted That Met QC Criteria

July 11, 2019

Last Verified

July 1, 2019

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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