[Research advances of occludin in vascular endothelial injury]

Endothelial tight junctions (TJs) serve as an important barrier in vascular endothelial structure and maintain vascular function homeostasis. Occludin, the most representative tight junction protein, is involved in sealing cell connections and maintaining the integrity and permeability of vascular endothelium. Recent studies have shown that alterations in the expression, distribution, and structure of endothelial TJs may lead to many related vascular diseases and pathologies (such as stroke, atherosclerosis, and pulmonary hypertension etc.). Here, we reviewed the research advances on the relationship between occludin and vascular endothelial injury, including the biological information of occludin, the signal pathways that occludin exerts the protective effect of vascular endothelium, and the relationship between occludin and vascular endothelial injury-related diseases.

[Mechanisms of adiponectin protection against diabetes-induced vascular endothelial injury]

The incidence and mortality rates of diabetes with cardiovascular complications are continually rising, and diabetic cardiovascular disease is becoming a major public health issue that threatens human health. Acute endothelial dysfunction and chronic cellular damage caused by diabetes are important risk factors for diabetic cardiovascular disease and related mortality. Adiponectin is an adipocyte-derived molecule with significant cytoprotective effects, including the protection against diabetes-induced vascular endothelial injury. Here we review the mechanisms of adiponectin protective effects on acute vascular endothelial dysfunction and chronic structural damage induced by diabetes.

[Research advances in the regulation of cardiovascular metabolic disorders and its related risk factors by C1q/TNF related proteins]

The complement C1q/TNF related protein (CTRP) family is rapidly growing and currently comprises 15 members. Although CTRP proteins share a common structure composed of four distinct domains: a signal peptide at the N terminus, a short variable region, a collagenous domain, and a C-terminal globular domain, which is homologous to adiponectin, each CTRP has a unique tissue expression profile and varied function. In this review we focus on the biochemistry and pleiotropic functions of CTRPs as new molecular mediators regulating cardiovascular metabolic disorders and its related risk factors diseases.

[Effects of thyroid hormone on macrophage dysfunction induced by oxidized low-density lipoprotein]

It has been recognized that patients with hypothyroidism have higher risks of atherosclerosis and coronary heart disease, however, the mechanisms are largely unknown. Considering that macrophage dysfunction plays an important role in the formation and development of atherosclerosis plaques, this study aimed to investigate the direct effects of thyroid hormone on macrophage functions and to provide new insight for the mechanism of hypothyroid atherosclerosis. RAW264.7 cells (mouse leukaemic monocyte macrophage cell line) were incubated with oxidized low-density lipoprotein (oxLDL) to establish macrophage foam cells model in vitro, and the protective effects of different concentration of thyroxine (T4) on the macrophage foam cells function were explored. The proliferation, migration and cell aging of macrophages were detected by MTT method, scratch test and β-galactosidase staining respectively. The ELISA method was used to detect the secretion of tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and interleukin-1β (IL-1β). Western blot analysis was applied to measure the phosphorylation of focal adhesion kinase (FAK), which was required for the process of proliferation and migration of macrophages. The results showed that oxLDL significantly inhibited the macrophage proliferation and migration, induced cell senescence, and promoted the secretion of TNF-α, MCP-1, and IL-1β; while T4 reversed those effects of oxLDL on macrophage in a concentration-dependent manner. Moreover, oxLDL increased the phosphorylation of FAK in macrophage, while T4 concentration-dependently reversed the effect. These results suggest that T4 modulates macrophage proliferation, migration, senescence, and secretion of inflammation factors in a concentration-dependent way.

Vascular dysfunction in the offspring of AT1 receptor antibody-positive pregnant rats during high-salt diet

Antibody against the angiotensin AT1 receptor (AT1-Ab) could disturb placental development. The placenta is the key organ between mother and fetus. Placental damage will seriously impair fetal growth and development in utero, leading to intrauterine growth restriction (IUGR). Based on the fetal origins of adult disease (FOAD) hypothesis, IUGR could increase a propensity to develop adult onset cardiovascular disease (CVD). The present study was designed to determine whether vascular function has changed in the adult offspring of AT1-Ab positive pregnant rats. Twenty four female rats (8-week-old, AT1-Ab negative) were randomly divided into two groups, immunized and vehicle groups. Immunized group received active immunization to establish AT1-Ab-positive model, while vehicle group was subjected to Freund's adjuvant without antigen. After 8 weeks of immunization, the antibody titers in sera from the female rats were detected by enzyme-linked immunosorbent assay (ELISA). Then all the female rats were mated with normal Wistar male rats and became pregnant. Immunized/vehicle group offspring rats (I offspring/V offspring) were raised to 40-week-old under standard chow feeding. Then the two groups' offspring rats were given a high-salt diet for 12 weeks (4% NaCl in chow feeding). Systolic blood pressure (SBP) was measured dynamically by noninvasive blood pressure system. The vascular ring experiment was performed to detect vascular function and reactivity. As detected by ELISA, the titers of antibody peaked at the 8th week (OD values: 2.75 ± 0.08 vs 0.33 ± 0.01, P < 0.01 vs vehicle group at the same time point). There was no significant difference of SBP between the two groups' offspring rats during the high-salt diet (P > 0.05). Isolated thoracic aortic rings of I offspring had significantly decreased constriction under norepinephrine treatment (P < 0.01 vs V offspring) and significantly decreased dilation under acetylcholine treatment (P < 0.05 vs V offspring). These results suggest that the offspring of AT1-Ab-positive pregnant rats are more susceptible to vascular functional abnormality while being fed high-salt diet.