Circulating angiogenic cell dysfunction in patients with hereditary hemorrhagic telangiectasia

Area of Science:

• Vascular Biology
• Regenerative Medicine
• Genetics

Background:

• Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant vascular disorder.
• Circulating angiogenic cells (CACs) are crucial for vascular repair and regeneration.

Purpose of the Study:

• To investigate the functional capacity of CACs derived from HHT patients.
• To compare CACs from HHT patients with those from healthy controls.

Main Methods:

• Flow cytometry to assess cell surface markers (CD34, CD133, VEGFR2) on peripheral blood mononuclear cells (PBMNCs).
• Culture of PBMNCs to obtain early outgrowth CACs and analysis of endothelial cell (EC) phenotype.
• Assays for CAC apoptosis (Annexin V) and migration (Boyden chamber).
• Real-time RT-PCR to measure mRNA expression of endoglin (ENG), ALK1, and eNOS in CACs.

Main Results:

• HHT patients had a higher percentage of CD34+ cells in PBMNCs compared to controls.
• CACs from HHT patients displayed reduced EC markers, increased apoptosis, and blunted migration.
• CACs from HHT patients showed significantly lower mRNA levels of ENG, ALK1, and eNOS.

Conclusions:

• CACs from HHT patients exhibit functional impairments.
• These functional deficits suggest a reduced capacity of HHT-derived CACs to repair vascular lesions.