Context: Acromegaly increases cardiovascular risk, possibly due to the high prevalence of classical risk factors. However, in vitro studies show a protective role of GH/IGF-1 on the endothelium.
Objective: The objective of the study was to investigate circulating endothelial progenitor cells (EPCs), a marker of vascular regeneration, in acromegalic patients and how they are affected by acromegaly treatment.
Design: This was a cross-sectional case-control and observational study.
Setting: The study was conducted at a tertiary ambulatory referral endocrinology center.
Patients: Forty-three acromegalic patients (26 active; 17 inactive) and 43 control subjects matched by age, gender, and degree of glucose tolerance participated in the study.
Intervention: Circulating EPCs were quantified by flow cytometry based on the expression of CD34, CD133, and kinase insert domain-containing receptor (KDR). Nine patients with active acromegaly were reevaluated after 24 weeks of treatment with somatostatin analogs (SSAs).
Main outcome measure: Differences in EPC levels between patients and controls were measured.
Results: Acromegalic patients showed a significant reduction of the total CD34(+)KDR(+) EPC population compared with controls, which was more evident in patients without diabetes or hypertension. More definite CD34(+)CD133(+)KDR(+) EPCs were reduced in patients with active compared with those with inactive acromegaly and compared with controls. The number of CD34(+)CD133(+)KDR(+) EPCs correlated with IGF-1 levels (r = -0.45; P < .001), fasting plasma glucose (r = -0.40; P = .004), and the homeostasis model assessment index of insulin resistance (r = -0.32; P = .026). CD34(+)CD133(+)KDR(+) EPCs increased 2-fold after SSA treatment.
Conclusions: Acromegalic patients have a reduced endothelial regenerative capacity, possibly due to activation of the GH/IGF-1, rather than concomitant risk factors. Treatment with SSAs can restore immature EPCs to normal levels.