Korean Circ J.  2012 May;42(5):329-334. 10.4070/kcj.2012.42.5.329.

The Number of Endothelial Progenitor Cells is Decreased in Patients With Non-Dipper Hypertension

• Kim S
• Kim NH
• Kim YK
• Yoo JH
• Shin SN
• Ko JS
• Kim YK
• Rhee SJ
• Yun KH
• Lee EM
• Yoo NJ
• Oh SK
• Jeong JW

• KMID: 2028761
• DOI: http://doi.org/10.4070/kcj.2012.42.5.329

Abstract

BACKGROUND AND OBJECTIVES
Circulating endothelial progenitor cells (EPCs) play a key role in the maintenance of endothelial homeostasis and promote vascular repair. A reduced number of EPCs and the functional activity have been associated with several cardiovascular risk factors. However, the relationship between the number of EPCs and circadian rhythm of the blood pressure (BP) remains unclear. The purpose of the present study was to evaluate the relationship between the circadian rhythm of the BP and EPCs in patients with essential hypertension.
SUBJECTS AND METHODS
A total of 45 patients with essential hypertension who were newly identified by outpatient BP measurements, underwent 24-hour ambulatory BP monitoring. Among the 45 patients with essential hypertension, 20 were classified as dippers (12 men and 8 women; mean age 48+/-14 years) and 25 as non-dippers (14 men and 11 women; mean age 52+/-18 years). The EPC count was isolated from the peripheral bloodstream and quantified by flow cytometry.
RESULTS
The baseline clinical characteristics were similar between the dipper and non-dipper hypertensive patients. The circulating EPCs were statistically reduced in the non-dipper patients as compared to the dippers (104+/-60 vs. 66+/-47 EPCs per 106 mononuclear cells, p=0.027). The circulating EPC level correlated positively with the circadian changes in the systolic and diastolic BP (r=0.435, p=0.003, and r=0.310, p=0.038, respectively).
CONCLUSION
The present study demonstrated that the EPC count was reduced in the peripheral bloodstream in non-dipper hypertensive patients.

Keyword

Hypertension; Circadian rhythm; Stem cells

MeSH Terms

Blood Pressure
Circadian Rhythm
Homeostasis
Humans
Hypertension
Male
Outpatients
Phosphorylcholine
Risk Factors
Stem Cells
Phosphorylcholine

Figure

• 

  Fig. 1 Quantification of EPCs by flow cytometry. Circulating EPCs were identified by flow cytometry with low cytoplasmic granularity (R1) and with expression of cell surface antigens such as CD45lowCD34+ VEGFR2+. Arrows indicate CD45lowCD34+ VEGFR2+ cells. EPCs: endothelial progenitor cells, VEGFR2: vascular endothelial growth factor receptor 2, SSC: side scather, FITC: fluorescein isothiocyanate.

• 

  Fig. 2 Comparison of the difference in the EPC count between the dippers and non-dippers. The absolute number of circulating EPCs was significantly reduced in the non-dipper hypertensive patients as compared to the dippers (104±60 vs. 66±47 EPCs per 106 mononuclear cells, p=0.027). EPC: endothelial progenitor cell, VEGFR2: vascular endothelial growth factor receptor 2, MNCs: mononuclear cells.

• 

  Fig. 3 Relationship between the EPC count and circadian changes in the BP. A: the number of circulating EPCs correlated positively with the circadian changes in the systolic blood pressure (r=0.435, p=0.003). B: the number of circulating EPCs also correlated positively with circadian changes in the diastolic blood pressure (r=0.310, p=0.038).

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