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

• Published in: Hypertension (Dallas, Tex. 1979) Tex. 1979), 2004-08, Vol.44 (2), p.191-194
• Main Authors: Puato, Massimo, Faggin, Elisabetta, Favaretto, Elisabetta, Bertipaglia, Barbara, Rattazzi, Marcello, Rizzoni, Damiano, Gamba, Gian Paolo, Sartore, Saverio, Rosei, Enrico Agabiti, Pessina, Achille Cesare, Pauletto, Paolo
• Format: Article
• Language: English
• Subjects: Aged; Aging - pathology; Antihypertensive agents; Arterial hypertension. Arterial hypotension; Arterioles; Biological and medical sciences; Biopsy; Blood and lymphatic vessels; Blood vessels and receptors; Cardiology. Vascular system; Cardiovascular system; Cell Differentiation; Child; Child, Preschool; Fundamental and applied biological sciences. Psychology; Humans; Hypertension - pathology; Immunohistochemistry; Infant; Medical sciences; Middle Aged; Muscle, Skeletal - cytology; Muscle, Skeletal - pathology; Muscle, Smooth - cytology; Muscle, Smooth - pathology; Pharmacology. Drug treatments; Rectus Abdominis - pathology; Vertebrates: cardiovascular system
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/01.HYP.0000133692.47754.e5

Significant structural and functional changes in smooth muscle cells (SMCs) of microvessels (diameter 30 to 300 μm) 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 analyzed16 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 Apla1-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 (P < 0.0005) in normotensive adults (0.22±0.17) than in children (0.98±0.61). Even more significant reduction was found in hypertensive adults compared with control adults (P = 0.013) and children (P < 0.0005). The qualitative immunocytochemistry analysis by NM-F6 revealed 2 differentiation patterns of the media layer of microvesselspositive or negative. In hypertensive subjects, the percentage of microvessels positive to NM-F6 was 49.8±35.6%, close to that found in children (50.6±12.6%), whereas in normotensive subjects it was significantly lower (24.4±21.1%). The following conclusions were drawn. (1) The medial layer of microvessels is heterogeneous in terms of SMC differentiation. (2) In hypertension, a prevalence of fetal-type SMCs takes place in microvessels, resembling that of children. Compared with children, a rarefaction of microvessels is present in normotensive adults that is even more remarkable in hypertensive adults.