Apolipoprotein E ϵ4 allele, skin vessel reactivity and vascular risk factors in Alzheimerʹs disease

The apolipoprotein E (ApoE) ϵ4 allele is strongly associated with Alzheimerʹs disease (AD), and is, at the same time, a risk factor for cardiovascular disease. Recently, it has also been suggested that skin vessel reactivity is impaired in AD. The aim of this study was to assess the impact of the ApoE ϵ4 allele on the results of skin vessel reactivity tests and vascular risk factors such as cholesterol and blood pressure in AD. Fourteen non-smoking patients, who were in good general health and took no medicines, were tested. Three vasodilating substances with different modes of action, acetylcholine (ACh), isoprenaline and nitroprusside, were iontophoresed into the skin and the resultant vasodilation of the skin vessels was evaluated with the aid of a newly developed laser Doppler perfusion imager. The results of the tests did not differ significantly between the patient group with (n = 10) and without (n = 4) the ApoE ϵ4 allele, perhaps due to the small number of patients. The results of the skin vessel reactivity tests of the patient subgroups were also compared to those of healthy, non-smoking, non-medicating, age-matched controls. The findings of that comparison suggest, that the presence of the ϵ4 allele in AD might have an impact on skin vessel reactivity to the cholinergic agonist ACh.