The Relation between Serum Endostatin Level and Carotid Atherosclerosis in Healthy Residents of Japan: Results from the Kyushu and Okinawa Population Study (KOPS)

New Dawn for Atherosclerosis: Vascular Endothelial Cell Senescence and Death

Endothelial cells (ECs) form the inner linings of blood vessels, and are directly exposed to endogenous hazard signals and metabolites in the circulatory system. The senescence and death of ECs are not only adverse outcomes, but also causal contributors to endothelial dysfunction, an early risk marker of atherosclerosis. The pathophysiological process of EC senescence involves both structural and functional changes and has been linked to various factors, including oxidative stress, dysregulated cell cycle, hyperuricemia, vascular inflammation, and aberrant metabolite sensing and signaling. Multiple forms of EC death have been documented in atherosclerosis, including autophagic cell death, apoptosis, pyroptosis, NETosis, necroptosis, and ferroptosis. Despite this, the molecular mechanisms underlying EC senescence or death in atherogenesis are not fully understood. To provide a comprehensive update on the subject, this review examines the historic and latest findings on the molecular mechanisms and functional alterations associated with EC senescence and death in different stages of atherosclerosis.

The Role of Biomarkers in Atherothrombotic Stroke-A Systematic Review

Stroke represents the primary debilitating disease in adults and is the second-highest cause of death worldwide. Atherosclerosis, the most prevalent etiology for vascular conditions, is a continuous process that gradually creates and develops endothelial lesions known as atherosclerotic plaques. These lesions lead to the appearance of atherothrombotic stroke. In the last decades, the role of biological biomarkers has emerged as either diagnostic, prognostic, or therapeutic targets. This article aims to create a list of potential biomarkers related to atherothrombotic stroke by reviewing the currently available literature. We identified 23 biomarkers and assessed their roles as risk factors, detection markers, prognostic predictors, and therapeutic targets. The central aspect of these biomarkers is related to risk stratification, especially for patients who have not yet suffered a stroke. Other valuable data are focused on the predictive capabilities for stroke patients regarding short-term and long-term prognosis, including their influence over the acute phase treatment, such as rt-PA thrombolysis. Although the role of biomarkers is anticipated to be of extreme value in the future, they cannot yet compete with traditional stroke neuroimaging markers but could be used as additional tools for etiological diagnosis.

High fluid shear stress prevents atherosclerotic plaque formation by promoting endothelium denudation and synthetic phenotype of vascular smooth muscle cells

Low blood fluid shear stress (SS) promotes vascular remodeling and atherosclerosis; however, the effects of high (H)SS on vascular remodeling and atherogenesis is not fully clarified. The major goal of this study was to investigate the role of HSS in atherosclerotic plaque formation. A perivascular SS modifier was implanted in the right carotid artery of apolipoprotein E (ApoE)^−/− mice to induce HSS, whereas the left carotid artery represented undisturbed (U)SS as a control in vivo. In vitro modeling used human umbilical vein endothelial cells and vascular smooth muscle cells exposed to HSS (2.5 Pa) using a parallel-plate flow system. The results demonstrated that there were no plaque formations or endothelial cells in the HSS regions of the carotid artery in ApoE^−/− mice. The number of umbilical vein endothelial cells was markedly decreased in a time-dependent manner in HSS. HSS significantly decreased α-smooth muscle actin and increased osteopontin protein expression levels compared with USS in vascular smooth muscle cells (P<0.05). In addition, HSS significantly increased the protein expression levels of collagen α1(XVIII) chain/endostatin and matrix metalloproteinase-8 in vascular smooth muscle cells. These data indicated that HSS may prevent atherosclerotic plaque formation through endothelium denudation and contractile-to-synthetic phenotypic conversion of smooth muscle cells.

Effect of Age and Acute Exercise on Circulating Angioregulatory Factors

The balance of angiogenic factors, including vascular endothelial growth factor (VEGF), and angiostatic factors, like thrombospondin-1 (TSP-1) and endostatin, controls striated muscle angiogenic responses to exercise training. The effect of age on circulating levels of these factors following a bout of exercise is unclear. The authors hypothesized that older adults would have lower circulating VEGF but higher TSP-1 and endostatin after exercise compared with young adults. Ten young and nine older participants cycled for 45 min at 60% estimated HRmax. Serum [VEGF], [TSP-1], and [endostatin] obtained before (PREX), immediately after (POSTX0), and 3 hr after (POSTX3) exercise were analyzed. [VEGF] increased in older adults only from PREX to POSTX0 (p < .05). [TSP-1] increased in both age groups (p < .05). There was no effect of age or exercise on [endostatin]. In conclusion, immediately after exercise, both groups had a similar increase in [TSP-1], but [VEGF] increased in older adults only.

Positive association between abdominal aortic diameter and serum collagen XVIII levels

BACKGROUND

The identification of abdominal aortic aneurysm (AAA) biomarker offers a perspective to determine disease progress and rupture risk. The aim of our study was to evaluate the association between selected circulating biomarkers and diameter of abdominal aorta.

METHODS

One hundred and two patients (88 men and 14 women) with mean age 70.0±8.7 years were included in a single center cross-sectional study conducted between February 2016 and October, 2018. AAA was defined as subrenal aortic dilatation ≥3 cm. Serum biomarker concentrations (insulin-like growth factor-1, peroxiredoxin-1, collagen IV, collagen XVIII) were measured by an enzyme-linked immunosorbent assay (ELISA). Adjustments including variables with different baseline distribution at univariate level with P<0.1 (age, body mass index, coronary artery disease, fibrinogen) were performed in multivariate models.

RESULTS

Higher collagen XVIII was found in AAA patients in comparison with the control group of patients (39.5 vs. 25.0 ng/mL; P=0.002). Diameter of abdominal aorta was positively associated with collagen XVIII levels in univariate (B=0.16; P=0.004), and in multivariate analysis (B=0.14; P=0.027), i.e. increase in collagen XVIII by 1 ng/mL corresponded to an increase in abdominal aortic diameter by 0.14 mm. Patients with serum collagen XVIII levels in the third tertile (˃47 ng/mL) had 4.23 times higher risk of AAA compared to patients with collagen XVIII levels in the first and second tertiles (OR 4.23; 95% CI 1.42-11.6; P=0.020). No association was found between other examined biomarkers and abdominal aortic diameter.

CONCLUSIONS

Diameter of abdominal aorta was positively associated with serum collagen XVIII level.

Validation of an enzyme-linked immunosorbent assay (ELISA) for quantification of endostatin levels in mice as a biomarker of developing glomerulonephritis

Endostatin, the C-terminal fragment of type XVIII collagen, was shown to be one of the most potent endothelial cell-specific inhibitors of angiogenesis. As altered circulating endostatin concentration is associated with impaired kidney function, new tools for measuring endostatin in rodents may be helpful to further investigate and understand its role within kidney disease progression. A novel and commercially available ELISA for the quantification of mouse and rat endostatin was developed and validated according to international quality guidelines including the parameters specificity, robustness, accuracy, dilution linearity, precision, limit of detection (LOD) and lower limit of quantification (LLOQ). Endostatin and blood urea nitrogen (BUN) concentration were measured in mice with a glomerulonephritis phenotype. The validation revealed that within the range of 0.5–32 nmol/L the immunoassay is robust and highly specific for the measurement of rodent endostatin with high sensitivity (LOD 0.24 nmol/L, LLOQ 0.5 nmol/L) and good reproducibility (intra- and inter-assay CV <10%). Also accuracy and dilution linearity were within the range of acceptance. BCL2 transgenic and ETV6/RUNX1;BCL2 double transgenic mice develop a glomerulonephritis phenotype over time, which was displayed by staining of kidney sections. Even before full manifestation of disease serum endostatin concentration rises significantly, whereas BUN levels just slightly increase. This newly developed and commercially available ELISA provides a reliable and accurate tool for the quantification of mouse and rat endostatin and may give new perspectives in the investigation of the role of endostatin as an important and early biomarker for reduced kidney function. Measurement of endostatin concentration is recommended to be used as a superior biomarker for chronic kidney disease compared to BUN.

Association of the Serum Endostatin Level, Renal Function, and Carotid Atherosclerosis of Healthy Residents of Japan: Results from the Kyushu and Okinawa Population Study (KOPS)

Aim: To analyze associations among the serum endostatin level, renal function, and carotid atherosclerosis of healthy residents of Japan.

Methods: Among 1,057 Japanese residents who attended free public physical examinations between 2010 and 2011, we evaluated the data of 648 healthy residents (200 men and 448 women, age 24 to 84 years) for whom the serum endostatin level and common carotid intima-media thickness (IMT) were measured. Renal function was assessed by estimated glomerular filtration rate (eGFR). Multiple linear regression analysis was done to determine the association of eGFR and serum endostatin level after adjustment for known covariates. Mediation analysis was done using Baron and Kenny's regression approach.

Results: The median endostatin level was 63.7 ng/mL (interquartile range: 49.7–93.2). The mean eGFR was 78.4 ± 14.8 mL/min/1.73m². Univariate analysis showed that age (r = −0.37, P < 0.01), non current smoking (85.8 ± 13.0 vs. 77.5 ± 14.8 mL/min/1.73 m², P < 0.01), hemoglobin A1c (r = −0.08, P = 0.05), low-density lipoprotein-cholesterol (r = −0.13, P < 0.01), uric acid (r = −0.15, P < 0.01), carotid IMT (r = −0.11, P < 0.01), and log-transformed endostatin (r = −0.36, P < 0.01) were significantly associated with eGFR. In multiple linear regression analysis, log-transformed endostatin was significantly associated with eGFR (beta = −0.24, P < 0.01). While, carotid IMT was no longer significant. Mediation analysis showed serum endostatin level to be a mediator in the association between carotid IMT and eGFR.

Conclusions: The association between carotid IMT and eGFR is mediated by the serum endostatin level of healthy individuals.