Functional Investigation of Endothelial Function and Regenerative Cell Exhaustion (FIERCE)

October 25, 2023 updated by: Canadian Medical and Surgical Knowledge Translation Research Group

Functional Investigation of Endothelial Function and Regenerative Cell Exhaustion in Type 2 Diabetes

FIERCE is an observational cross-sectional study. Approximately 90 individuals living with type 2 diabetes (T2D) and/or individuals living without diabetes will be randomized (2:1).

The primary objective of this trial is to determine if there are differences in the content and function of circulating vascular regenerative (VR) progenitor cell subsets isolated from individuals living with T2D versus individuals not living with T2D. The main question this study aims to answer is: Does T2D compromise or enhance VR cell functionality?

Each participant will be asked to provide a single blood sample. Blood samples will be processed to enumerate the number of vessel-repairing cells and determine the functionality of the different subtypes of vessel-repairing cells.

Study Overview

Status

Not yet recruiting

Conditions

Detailed Description

Type 2 diabetes (T2D) is a significant and prevalent global health concern. Individuals diagnosed with T2D are at an elevated risk of developing atherosclerotic cardiovascular (CV) disease, a leading cause of global morbidity and mortality.

Blood vessel homeostasis plays a central role in the status of CV health. Circulating vascular regenerative (VR) progenitor cells, which mediate the endogenous processes of angiogenesis, vasculogenesis, and arteriogenesis, are critical in orchestrating vessel repair. In T2D, chronic hyperglycemia and concomitant oxidative stress create a maladaptive environment that impairs vessel repair. T2D can lead to a chronic state known as vascular regenerative cell exhaustion (VRCE), characterized by the depletion of, and dysfunction in, circulating VR progenitor cells. The available data indicate that VRCE associated with T2D can lead to VR cell dysfunction and compromised vascular repair.

We have developed a multi-parametric flow cytometry assay to measure VR progenitor cell content in blood samples. This assay utilizes the cytosolic detoxification enzyme aldehyde dehydrogenase (ALDH), which is highly expressed in progenitor cells from hematopoietic, endothelial, and mesenchymal stromal cell lineages. This enzyme protects progenitor cells from oxidative damage that is driven by reactive oxygen species. ALDH activity is reduced by up to 100-fold as progenitor cells differentiate towards more expendable effector cells. As such, we identify cells with high or low ALDH activity in combination with cell surface markers to distinguish progenitor cell subsets (ALDHhi) from more differentiated progeny (ALDHlow). Used in conjunction with 'side scatter' (SSC), a parameter that correlates with the granularity or complexity of a cell, this assay can distinguish between and quantify ALDHhiSSClow hematopoietic/endothelial precursor cells, ALDHhiSSCmid monocytes, and ALDHhiSSChi granulocyte precursors. Previously, bone marrow-derived ALDHhiSSClow cells were shown to co-express the primitive cell markers CD34 and CD133 and exhibit multipotent hematopoietic colony-forming ability in vitro. In the immunodeficient NOD/SCID mouse model of hindlimb ischemia, transplantation of ALDHhiSSClow cells into the ischemic limb led to improved muscle perfusion recovery. The potential of this cell therapy to prevent amputations in individuals with critical limb ischemia has been evaluated in clinical trial settings.

The peripheral blood of individuals living with T2D for >10-years exhibit a depletion of ALDHhiSSClow VR progenitor cells, lower frequencies of ALDHhiSSCmid monocytes with vessel reparative function, and an increased frequency of ALDHhiSSChi inflammatory granulocyte precursors compared to that from individuals not living with T2D. The VRCE phenotype was partially reversed in people living with T2D and established coronary artery disease (CAD) after they had been on the SGLT2 inhibitor empagliflozin for 6 months. Obesity-induced VR cell depletion was also reversed by 3 months post-bariatric surgery. These findings collectively provided a mechanistic link between T2D, obesity, and impaired vessel homeostasis/repair, and also established that VRCE may be therapeutically reversed in a high CV-risk diabetic milieu.

FIERCE will assess VR cell content in individuals living with T2D (<10-years duration) and age- and sex-matched individuals not living with T2D. It will also assess the function of circulating ALDHhi VR cells through: (1) Endothelial peripheral arterial tonometry (EndoPAT) to clinically analyze endothelial function through reactive hyperemic index, (2) multipotent hematopoietic colony formation assays in vitro, (3) single-cell RNA-sequencing (scRNA-seq) that is focused on mRNA expression associated with angiogenesis, and (4) quantitative, label-free secretome analyses to determine changes in pro-angiogenic protein secretion.

We hypothesize that VRCE impairs vascular repair and blood vessel regeneration during T2D and is partly caused by impaired pro-angiogenic properties of VR progenitor cell subsets. Specifically, we postulate that multipotent hematopoietic colony formation, pro-angiogenic cytokine mRNA expression, and pro-angiogenic protein release will be lower in ALDHhi progenitor cell subsets from individuals living with T2D relative to participants not living with T2D. We also predict that individuals living with T2D will exhibit a lower reactive hyperemic index compared to individuals not living with T2D.

Characterization of ALDHhi progenitor VR cell dysfunction in the setting of T2D will generate proof-of-concept to support the potential use of VR cell content as a quantifiable and functional indicator of vascular health.

Study Type

Observational

Enrollment (Estimated)

90

Contacts and Locations

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

Study Contact

Study Locations

  • Canada
    • Ontario
      • Scarborough, Ontario, Canada, M1S4N6
        • Diagnostic Assessment Centre
        • Contact:
          • Subodh Verma, MD, PhD

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Participants will be identified from primary care clinics in the Greater Toronto Area using paper-based and electronic medical records.

Description

Inclusion Criteria:

  • Adults ≥18 years of age.
  • Willing to provide written informed consent.
  • Documented history of T2D
  • No documented history of diabetes

Exclusion Criteria:

  • Unable or unwilling to provide written informed consent or provide a peripheral blood sample.
  • Any life-threatening disease expected to result in death within two years of consent.
  • Any malignancy not considered cured (except basal cell carcinoma of the skin). An individual is considered cured if there has been no evidence of cancer recurrence for the five years prior to screening.
  • Known severe liver disease.
  • White blood cell count ≥15 x 10^9/L.
  • Active infectious disease requiring systemic antibiotic or anti-viral agents.
  • Known acquired immunodeficiency syndrome such as HIV.
  • Treated autoimmune disorders (e.g. T1D and LADA).
  • On oral steroid therapy (e.g. prednisone or other corticosteroids) or other immunosuppressive agents (e.g. methotrexate).

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

Cohorts and Interventions

Group / Cohort
Type 2 Diabetes
Participants living with type 2 diabetes for less than 10 years will be recruited.
No Diabetes
Participants not living with diabetes will be recruited.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Hematopoietic colony formation in ALDHhiSSClow regenerative cell subsets
Time Frame: Baseline
The capacity for total multipotent hematopoietic colony formation in ALDHhiSSClow regenerative cell subsets isolated from individuals living with T2D versus individuals not living with T2D.
Baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Endothelial function
Time Frame: Baseline
Endothelial peripheral arterial tonometry (EndoPAT) will be utilized to clinically analyze endothelial function through reactive hyperemic index in individuals living with T2D and individuals not living with T2D.
Baseline
Frequency and absolute number of circulating ALDHhiSSClowCD133+ progenitor cells
Time Frame: Baseline
The change in the frequency and absolute number of circulating ALDHhiSSClowCD133+ progenitor cells between individuals living with T2D versus age- and sex-matched individuals not living with T2D
Baseline

Collaborators and Investigators

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

Sponsor

Canadian Medical and Surgical Knowledge Translation Research Group

Collaborators

Unity Health Toronto
University of Western Ontario, Canada

Investigators

  • Principal Investigator: Subodh Verma, MD, PhD, Unity Health Toronto
  • Principal Investigator: David A Hess, PhD, Robarts Research Institute, London, Ontario

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

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 (Estimated)

November 1, 2023

Primary Completion (Estimated)

December 1, 2025

Study Completion (Estimated)

June 1, 2026

Study Registration Dates

First Submitted

October 25, 2023

First Submitted That Met QC Criteria

October 25, 2023

First Posted (Actual)

October 31, 2023

Study Record Updates

Last Update Posted (Actual)

October 31, 2023

Last Update Submitted That Met QC Criteria

October 25, 2023

Last Verified

October 1, 2023

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Pro00074548

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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