ABSTRACT
Introduction: An adipose tissue programming mechanism could be implicated in the extrauterine growth restriction (EUGR) of very preterm infants with morbidity in the cardiometabolic status later in life, as has been reported in intrauterine growth restriction. The aim of this study was to assess whether children with a history of prematurity and EUGR, but also with an adequate growth, showed alterations in the metabolic and inflammatory status. Methods: This was a case-control study. A total of 88 prepubertal children with prematurity antecedents were selected: 38 with EUGR and 50 with an adequate growth pattern (PREM group). They were compared with 123 healthy children born at term. Anthropometry, metabolic parameters, blood pressure (BP), C-reactive protein, hepatocyte growth factor (HGF), interleukin-6 (IL-6), IL-8, monocyte chemotactic protein type 1 (MCP-1), neural growth factor, tumour necrosis factor-alpha (TNF-α) and plasminogen activator inhibitor type-1 were analysed at the prepubertal age. Results: EUGR children exhibited higher BP levels and a higher prevalence of hypertension (46%) compared with both PREM (10%) and control (2.5%) groups. Moreover, there was a positive relationship between BP levels and values for glucose, insulin and HOMA-IR only in children with a EUGR history. The EUGR group showed higher concentrations of most of the cytokines analysed, markedly higher TNF-α, HGF and MCP-1 levels compared with the other two groups. Conclusion: EUGR status leads to cardiometabolic changes and a low-grade inflammatory status in children with a history of prematurity, and that could be related with cardiovascular risk later in life.
ABSTRACT
Proliferation of vascular smooth muscle cells (VSMCs) contributes to intimal thickening during atherosclerosis and restenosis. The cadherins are transmembrane proteins, which form cell-cell contacts and may regulate VSMC proliferation. In this study, N-cadherin protein concentration was significantly reduced by stimulation of proliferation with fetal calf serum (FCS) and platelet-derived growth factor-BB (PDGF-BB) in human saphenous vein VSMCs. Furthermore, overexpression of a truncated N-cadherin, which acts as a dominant-negative increased VSMC proliferation. The amount of an extracellular fragment of N-cadherin (approximately 90 kDa) in the media after 24 hours was increased by 12-fold by FCS and 11-fold by PDGF-BB, suggesting that N-cadherin levels are regulated by proteolytic shedding. Incubation with a synthetic metalloproteinase inhibitor or adenoviral overexpression of the endogenous tissue inhibitors of metalloproteinases (TIMPs) demonstrated that metalloproteinase activity was responsible in part for this proteolysis. Although total levels of beta-catenin protein were not affected, beta-catenin was translocated to the nucleus after stimulation with FCS and PDGF-BB. Our data indicates cadherin-mediated cell-cell contacts modulate proliferation in VSMCs. Furthermore, disruption of N-cadherin cell-cell contacts mediated in part by metalloproteinase activity occurs during VSMC proliferation, releasing beta-catenin and possibly inducing beta-catenin-mediated intracellular signaling.