Prevalence of Fetal-Type Smooth Muscle Cells in the Media of Microvessels From Hypertensive Patients

Abstract

Abstract-Significant structural and functional changes in smooth muscle cells (SMCs) of microvessels (diameter 30 to 300 m) occur in hypertension. However, in microvessels of hypertensive patients, the differentiation pattern of SMCs underlying such changes remains undefined. To analyze the differentiation pattern of SMCs (adult, postnatal, or fetal), 49 muscle biopsies (rectus abdominis) were analyzed: 16 from children (aged 11 months to 11 years), 15 from normotensive adults (aged 55 to 74 years), 18 from hypertensive adults (aged 55 to 74 years). Transverse cryosections of specimens were studied by immunocytochemistry using monoclonal antibodies SM-E7 and NM-F6, which recognize smooth muscle myosin heavy chain (MyHC) and A pla1 -like nonmuscle MyHC, respectively. The total number of microvessels was assessed via SM-E7 staining. The number of NM-F6 positive (fetal-type SMC) or negative (adult-type SMC) microvessels was assessed. The number of microvessels per area unit was considerably lower (PϽ0.0005) in normotensive adults (0.22Ϯ0.17) than in children (0.98Ϯ0.61). Even more significant reduction was found in hypertensive adults compared with control adults (Pϭ0.013) and children (PϽ0.0005). The qualitative immunocytochemistry analysis by NM-F6 revealed 2 differentiation patterns of the media layer of microvessels: positive or negative.In hypertensive subjects, the percentage of microvessels positive to NM-F6 was 49.8Ϯ35.6%, close to that found in children (50.6Ϯ12.6%), whereas in normotensive subjects it was significantly lower (24.4Ϯ21.1%). The following conclusions were drawn. (1

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