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          Grants & Funding: The NIAMS Extramural Program
          Clinical Trials in the Spotlight
          Exploration of blood flow regulation to bone in humans








Exploration of blood flow regulation to bone in humans FacebookEmailPrintFacebookEmail     
    The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) supports a range of clinical trials studying new and existing interventions for prevention and treatment of arthritis, musculoskeletal, and skin diseases.  Recruitment for this clinical trial complete.   Updates will be made  to this page when the study completes data analysis and results become available. Please check back often and find out how these studies have contributed to generating new knowledge about diseases and conditions within the NIAMS mission area.

Click on Main Page to learn more about actively recruiting research studies for which you or someone you know may be eligible.

Study Description

Without blood flow, bone cannot maintain its integrity. Bone blood flow responds to various local and systemic factors, however, bone perfusion in humans remains relatively unstudied. This study will investigate key mechanisms that regulate bone perfusion in able-bodied and contrast responses to those with spinal cord injury (SCI). SCI is a model of chronic reduced loading with loss of sympathetic regulation.

In tibial cortical bone, the study team will: 1) determine the impact of compressive loading with and without muscle contractions; 2) determine the impact of vascular sympathetic activity and systemic perfusion pressure; 3) compare the response between able- bodied and those with SCI.

Acute metabolic needs of bone due to loading increase flow substantially. In addition, the bone vasculature is innervated by a rich network of sympathetic nerves that serve a functional purpose in the control of blood flow. A critical limitation to the study of bone blood flow in humans has been the lack of non-invasive assessments. We developed a near infrared spectroscopy (NIRS) device to non-invasively assess blood content in bone and assessed tibial perfusion in response to exercise. Here, the study team will test the hypothesis that bone blood flow increases proportional to loading conditions in both able-bodied individuals and those with SCI. The study team will also test the hypothesis that there are decreases in blood bone flow that are proportional to increases in leg vascular sympathetic outflow in the able-bodied, but that changes in bone blood flow are proportional to changes in blood pressure in those with SCI. The proposed research will be some of the first to determine the control of bone flow in humans.

**ELIGIBILITY CRITERIA:**

Ages Eligible for Study:           18 Years to 40 Years   (Adult)

Sexes Eligible for Study:          All

Accepts Healthy Volunteers:  Yes

**Inclusion Criteria:**

healthy males and females
	individuals with spinal cord injuries, between 3 and 24 months post injury, with complete injuries according to the American Spinal Injury Association Impairment Scale A and B, with injuries at T6 and below**Exclusion Criteria:**

clinical signs or symptoms of heart disease
	hypertension
	coronary disease
	diabetes
	other neurological disease
	cancer
	recent weight change >15 pounds
	abnormal resting ECG
	pregnant and/or breastfeeding women
	underweight and obese individuals (body mass index between 18.5 and 29.9)
	use of amphetamines (Ritalin, Adderall, Concerta) in the past 48 hours
	tibial fracture or tibial stress fracture in the past year
	those with SCI will have no extreme spasticity to avoid spontaneous contractions
	use of baclofen for those with SCI**Study Design:**

Intervention Model: Single Group Assignment

Masking: None (Open Label)

Primary Purpose: Basic Science

**Study Location(s):**

Spaulding Hospital, Boston, Massachusetts, United States, 02129

**Study Website:**

https://www.clinicaltrials.gov/ct2/show/NCT04083794?term=NCT04083794&draw=2&rank=1


Last Updated: August 2022


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