Structural alterations in the microcirculation may be considered an important mechanism of organ damage. An increased media-to-lumen ratio of subcutaneous small resistance arteries has been demonstrated to predict the development of cardiocerebrovascular events in hypertensive patients. Alterations in the structure of small cerebral arteries have been demonstrated in animal models of experimental or genetic hypertension. However, no evaluation with reliable techniques has ever been performed in humans.
Twenty-eight participants were included in the present study: they were 13 hypertensive patients and 15 normotensive individuals. All participants underwent a neurosurgical intervention for benign or malign tumors. A small portion of morphologically normal cerebral tissue was excised from surgical samples and examined. Cerebral small resistance arteries (relaxed diameter around 200 μm) were dissected and mounted on an isometric and isobaric myograph, and the tunica media to internal lumen ratio was measured. In addition, cerebral cortical microvessel density (MVD) was also evaluated. The tissue was sectioned and stained for CD31, and MVD was measured with an automated image analyzer (percentage of area stained). Blood pressure values were evaluated, before surgical intervention, by standard sphygmomanometry.
M/L was significantly greater and MVD significantly lower in hypertensive patients than that in normotensive individuals. No difference between groups in collagen content or mechanical properties of cerebral small arteries was observed.
Our results indicate that structural alterations of small cerebral vessels are present in hypertensive patients compared with normotensive individuals, similar to those previously observed in subcutaneous small arteries.
aClinica Medica, Department of Medical and Surgical Sciences, University of Brescia, Brescia, Italy
bDepartment of Neurosurgery, Istituto Scientifico San Raffaele, Università Vita-Salute, Milan, Italy
cChair of Neurosurgery, University of Brescia, Italy
dChair of Human Anatomy, Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia, Italy
Received 7 October, 2008
Revised 20 November, 2008
Accepted 26 November, 2008
Correspondence to Professor Damiano Rizzoni, Clinica Medica, Department of Medical and Surgical Sciences, University of Brescia, c/o 2a Medicina, Spedali Civili, 25100 Brescia, Italy Tel: +39 30 396044; fax: +39 30 3384348; e-mail: firstname.lastname@example.org