Cerebral vasoreactivity and intima-media thickness in Down syndrome: A case-control study

Cerebral vasoreactivity, a surrogate marker of cerebrovascular disease, is not impaired in subjects with lifetime, untreated, congenital isolated GH deficiency

OBJECTIVES

Cerebrovascular disease (CeVD) is a major cause of death and disability. The role of the GH/IGF-I axis on CeVD risk is controversial. Patients with GH deficiency (GHD) in the setting of hypopituitarism often exhibit CeVD predisposing factors, like low nitric oxide generation, endothelial dysfunction, increased visceral fat mass, increased levels of LDL cholesterol, and increased intima-media thickness, a surrogate marker of atherosclerosis. However, several confounders such as the primary hypothalamic-pituitary lesion, hormonal replacement therapies, consequences of surgery and radiotherapy, may influence this relationship. Therefore, we decided to assess cerebral vasoreactivity, a surrogate marker of CeVD, in adult subjects with untreated isolated GHD (IGHD) due to the same homozygous null mutation in the GHRH receptor gene.

METHODS

A cross-sectional study was carried out in 25 adult IGHD subjects and 25 age- and gender-matched controls. Interview, physical examination, laboratory data, intima-media thickness measurement, and transcranial Doppler were performed. The intracranial hemodynamics (mean flow velocity, pulsatility and resistance indexes) were measured, and the response to the vasodilatory stimulus by breath-holding maneuver (breath-holding index) was calculated.

RESULTS

IGHD and control groups were similar in Framingham risk score and intima-media thickness. Similarly, there was no difference in mean flow velocity, pulsatility, resistance, and breath-holding index.

CONCLUSIONS

Lifetime, untreated IGHD does not cause impaired cerebral vasoreactivity.