Vascular Regenerative Cell Deficiencies in South Asian Adults.

Background: South Asian individuals shoulder a disproportionate burden of cardiometabolic diseases.

Objectives: The purpose of this study was to determine if vascular regenerative cell content varies significantly between South Asian and White European people.

Methods: Between January 2022 and January 2023, 60 South Asian and 60 White European adults with either documented cardiovascular disease or established diabetes with ≥1 other cardiovascular risk factor were prospectively enrolled. Vascular regenerative cell content in venous blood was enumerated using a flow cytometry assay that is based on high aldehyde dehydrogenase (ALDH) activity and cell surface marker phenotyping. The primary outcome was the difference in frequency of circulating ALDH progenitor cells, monocytes, and granulocytes between the 2 groups.

Results: Compared with White European participants, those of South Asian ethnicity were younger (69 ± 10 years vs 66 ± 9 years; P < 0.05), had lower weight (88 ± 19 kg vs 75 ± 13 kg; P < 0.001), and exhibited a greater prevalence of type 2 diabetes (62% vs 92%). South Asian individuals had markedly lower circulating frequencies of pro-angiogenic ALDHSSCCD133 progenitor cells (P < 0.001) and ALDHSSCCD14CD163 monocytes with vessel-reparative capacity (P < 0.001), as well as proportionally more ALDH progenitor cells with high reactive oxygen species content (P < 0.05). After correction for sex, age, body mass index, and glycated hemoglobin, South Asian ethnicity was independently associated with lower ALDHSSCCD133 cell count.

Conclusions: South Asian people with cardiometabolic disease had less vascular regenerative and reparative cells suggesting compromised vessel repair capabilities that may contribute to the excess vascular risk in this population. (The Role of South Asian vs European Origins on Circulating Regenerative Cell Exhaustion [ORIGINS-RCE]; NCT05253521).