Associations between plasma fibulin-1, pulse wave velocity and diabetes in patients with coronary heart disease

Association Between Plasma Fibulin-1 and Brachial-Ankle Pulse Wave Velocity in Arterial Stiffness

Arterial stiffness forms the basis of cardiovascular diseases (CVD) and is also an independent predictor of CVD risk. Early detection and intervention of arterial stiffness are important for improving the global burden of CVD. Pulse wave velocity (PWV) is the gold standard for assessing arterial stiffness and the molecular mechanism of arterial stiffness remains to be studied. Extracellular matrix (ECM) remodeling is one of the major mechanisms of arterial stiffness. Partial quantitative changes of ECM proteins can be detected in plasma. Therefore, we examined the hypothesis that a discovery proteomic comparison of plasma proteins between high arterial stiffness (baPWV ≥ 1,400 cm/s) and normal arterial stiffness (baPWV < 1,400 cm/s) populations might identify relevant changed ECM proteins for arterial stiffness. Plasma samples were randomly selected from normal arterial stiffness (n = 6) and high arterial stiffness (n = 6) people. Isobaric tags for relative and absolute quantitation (iTRAQ) based quantitative proteomics technique was performed to find a total of 169 differentially expressed proteins (DEPs). Nine ECM proteins were included in all DEPs and were all up-regulated proteins. Fibulin-1 had the highest statistically fold-change (FC = 3.7, p < 0.0001) in the high arterial stiffness population compared with the control group during the nine ECM proteins. The expression of plasma fibulin-1 in normal arterial stiffness (n = 112) and high arterial stiffness (n = 72) populations was confirmed through enzyme-linked immunosorbent assay (ELISA). Similarly, ELISA results showed that plasma concentrations of fibulin-1 in the high arterial stiffness group were higher than those in the normal arterial stiffness group (12.69 ± 0.89 vs. 9.84 ± 0.71 μg/ml, p < 0.05). Univariate analysis of fibulin-1 with brachial-ankle pulse wave velocity (baPWV) indicated that fibulin-1 was positively correlated with baPWV in all participants (r = 0.32, p < 0.01) and a stronger positive correlation between baPWV and fibulin-1 in high arterial stiffness group (r = 0.64, p < 0.0001) was found. Multiple regression analysis of factors affecting baPWV showed that fibulin-1 was also a significant determinant of the increased ba-PWV (R2 = 0.635, p = 0.001). Partial correlation analysis showed that baPWV increased with the growth of plasma fibulin-1(r = 0.267, p < 0.001). In conclusion, our results demonstrated that fibulin-1 is positively correlated with ba-PWV and an independent risk factor for arterial stiffness.

Extracellular Matrix Stiffness in Lung Health and Disease

The extracellular matrix (ECM) provides structural support and imparts a wide variety of environmental cues to cells. In the past decade, a growing body of work revealed that the mechanical properties of the ECM, commonly known as matrix stiffness, regulate the fundamental cellular processes of the lung. There is growing appreciation that mechanical interplays between cells and associated ECM are essential to maintain lung homeostasis. Dysregulation of ECM-derived mechanical signaling via altered mechanosensing and mechanotransduction pathways is associated with many common lung diseases. Matrix stiffening is a hallmark of lung fibrosis. The stiffened ECM is not merely a sequelae of lung fibrosis but can actively drive the progression of fibrotic lung disease. In this article, we provide a comprehensive view on the role of matrix stiffness in lung health and disease. We begin by summarizing the effects of matrix stiffness on the function and behavior of various lung cell types and on regulation of biomolecule activity and key physiological processes, including host immune response and cellular metabolism. We discuss the potential mechanisms by which cells probe matrix stiffness and convert mechanical signals to regulate gene expression. We highlight the factors that govern matrix stiffness and outline the role of matrix stiffness in lung development and the pathogenesis of pulmonary fibrosis, pulmonary hypertension, asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. We envision targeting of deleterious matrix mechanical cues for treatment of fibrotic lung disease. Advances in technologies for matrix stiffness measurements and design of stiffness-tunable matrix substrates are also explored. © 2022 American Physiological Society. Compr Physiol 12:3523-3558, 2022.

Relationship between the Plasma Fibulin-1 Levels, Pulse Wave Velocity, and Vascular Age in Asymptomatic Hyperuricemia

Fibulin-1 (FBLN-1), an elastin-associated extracellular matrix protein, has been found in blood and may play a role in the pathophysiological processes leading to cardiovascular disease (CVD). We aimed to investigate the relationship between fibulin-1 levels and the risk of CVD by evaluating vascular age derived from the Framingham Heart Study and brachial-ankle Pulse Wave Velocity (baPWV) in patients with asymptomatic hyperuricemia (AHU). In total, 66 patients with AHU and 66 gender- and age-matched healthy individuals were enrolled. The plasma fibulin-1 levels were measured by immunochemistry. Patients with AHU presented significantly higher vascular age [median (interquartile range): 54 (22) vs. 48 (14) years, P=0.01] and baPWV [mean±SD: 1373±223 vs. 1291±177 cm/s, P=0.02] than the healthy subjects; however, no significant difference was observed in the plasma fibulin-1 level between the patients with AHU and healthy subjects [median (interquartile range): 4018 (3838) vs. 3099 (3405) ng/mL, P=0.31]. A correlation between fibulin-1 levels and baPWV was observed only in patients with AHU (r=0.29, P=0.02); and there was also a suggestively statistically significant correlation between fibulin-1 levels and vascular age (r=0.22, P=0.08). However, these associations were rendered insignificant after adjustments for potential confounders. In healthy subjects, no correlation was observed between fibulin-1 levels and CVD risk. This study reveals that plasma fibulin-1 levels may reflect the CVD risk in patients with AHU, but the relationship is not robust.

Molecular pathophysiology of diabetes mellitus during pregnancy with antenatal complications

Gestational diabetes mellitus is a daunting problem accompanied by severe fetal development complications and type 2 diabetes mellitus in postpartum. Diagnosis of diabetic conditions occurs only in the second trimester, while associated antenatal complications are typically revealed even later. We acquired an assay of peripheral and cord blood samples of patients with different types of diabetes mellitus who delivered either healthy newborns or associated with fetopathy complications. Obtained data were handled with qualitative and quantitative analysis. Pathways of molecular events involved in diabetes mellitus and fetopathy were reconstructed based on the discovered markers and their quantitative alteration. Plenty of pathways were integrated to differentiate the type of diabetes and to recognize the impact of the diabetic condition on fetal development. The impaired triglycerides transport, glucose uptake, and consequent insulin resistance are mostly affected by faulted lipid metabolism (APOM, APOD, APOH, APOC1) and encouraged by oxidative stress (CP, TF, ORM2) and inflammation (CFH, CFB, CLU) as a secondary response accompanied by changes in matrix architecture (AFM, FBLN1, AMBP). Alterations in proteomes of peripheral and cord blood were expectedly unequal. Both up- and downregulated markers were accommodated in the cast of molecular events interconnected with the lipid metabolism, RXR/PPAR-signaling pathway, and extracellular architecture modulation. The obtained results congregate numerous biological processes to molecular events that underline diabetes during gestation and uncover some critical aspects affecting fetal growth and development.

Constitutive interpretation of arterial stiffness in clinical studies: a methodological review

Clinical assessment of arterial stiffness relies on noninvasive measurements of regional pulse wave velocity or local distensibility. However, arterial stiffness measures do not discriminate underlying changes in arterial wall constituent properties (e.g., in collagen, elastin, or smooth muscle), which is highly relevant for development and monitoring of treatment. In arterial stiffness in recent clinical-epidemiological studies, we systematically review clinical-epidemiological studies (2012–) that interpreted arterial stiffness changes in terms of changes in arterial wall constituent properties (63 studies included of 514 studies found). Most studies that did so were association studies (52 of 63 studies) providing limited causal evidence. Intervention studies (11 of 63 studies) addressed changes in arterial stiffness through the modulation of extracellular matrix integrity (5 of 11 studies) or smooth muscle tone (6 of 11 studies). A handful of studies (3 of 63 studies) used mathematical modeling to discriminate between extracellular matrix components. Overall, there exists a notable gap in the mechanistic interpretation of stiffness findings. In constitutive model-based interpretation, we first introduce constitutive-based modeling and use it to illustrate the relationship between constituent properties and stiffness measurements (“forward” approach). We then review all literature on modeling approaches for the constitutive interpretation of clinical arterial stiffness data (“inverse” approach), which are aimed at estimation of constitutive properties from arterial stiffness measurements to benefit treatment development and monitoring. Importantly, any modeling approach requires a tradeoff between model complexity and measurable data. Therefore, the feasibility of changing in vivo the biaxial mechanics and/or vascular smooth muscle tone should be explored. The effectiveness of modeling approaches should be confirmed using uncertainty quantification and sensitivity analysis. Taken together, constitutive modeling can significantly improve clinical interpretation of arterial stiffness findings.

The matrix proteins aggrecan and fibulin-1 play a key role in determining aortic stiffness

Stiffening of the aorta is an important independent risk factor for myocardial infarction and stroke. Yet its genetics is complex and little is known about its molecular drivers. We have identified for the first time, tagSNPs in the genes for extracellular matrix proteins, aggrecan and fibulin-1, that modulate stiffness in young healthy adults. We confirmed SNP associations with ex vivo stiffness measurements and expression studies in human donor aortic tissues. Both aggrecan and fibulin-1 were found in the aortic wall, but with marked differences in the distribution and glycosylation of aggrecan reflecting loss of chondroitin-sulphate binding domains. These differences were age-dependent but the striking finding was the acceleration of this process in stiff versus elastic young aortas. These findings suggest that aggrecan and fibulin-1 have critical roles in determining the biomechanics of the aorta and their modification with age could underpin age-related aortic stiffening.

Notch2 and Proteomic Signatures in Mouse Neointimal Lesion Formation

Supplemental Digital Content is available in the text.

Objective—

Vascular remodeling is associated with complex molecular changes, including increased Notch2, which promotes quiescence in human smooth muscle cells. We used unbiased protein profiling to understand molecular signatures related to neointimal lesion formation in the presence or absence of Notch2 and to test the hypothesis that loss of Notch2 would increase neointimal lesion formation because of a hyperproliferative injury response.

Approach and Results—

Murine carotid arteries isolated at 6 or 14 days after ligation injury were analyzed by mass spectrometry using a data-independent acquisition strategy in comparison to uninjured or sham injured arteries. We used a tamoxifen-inducible, cell-specific Cre recombinase strain to delete the Notch2 gene in smooth muscle cells. Vessel morphometric analysis and immunohistochemical staining were used to characterize lesion formation, assess vascular smooth muscle cell proliferation, and validate proteomic findings. Loss of Notch2 in smooth muscle cells leads to protein profile changes in the vessel wall during remodeling but does not alter overall lesion morphology or cell proliferation. Loss of smooth muscle Notch2 also decreases the expression of enhancer of rudimentary homolog, plectin, and annexin A2 in vascular remodeling.

Conclusions—

We identified unique protein signatures that represent temporal changes in the vessel wall during neointimal lesion formation in the presence and absence of Notch2. Overall lesion formation was not affected with loss of smooth muscle Notch2, suggesting compensatory pathways. We also validated the regulation of known injury- or Notch-related targets identified in other vascular contexts, providing additional insight into conserved pathways involved in vascular remodeling.

Preliminary analysis of proteome alterations in non-aneurysmal, internal mammary artery tissue from patients with abdominal aortic aneurysms

Objective

The pathogenesis of abdominal aortic aneurysms (AAA) involves a disturbed balance of breakdown and buildup of arterial proteins. We envision that individuals with AAA carry generalized arterial protein alterations either because of effects of genetically or environmental AAA risk factors or because of compensatory changes due to signaling molecules released from the affected aneurysmal tissue.

Approach

Protein extraction and quantitative proteome analysis by LC-MS/MS (liquid chromatography-mass spectrometry) was done on individual samples from the internal mammary artery from 11 individuals with AAA and 33 sex- and age-matched controls without AAA. Samples were selected from a biobank of leftover internal mammary arterial tissue gathered at coronary by-pass operations.

Results

We identified and quantitated 877 proteins, of which 44 were differentially expressed between the two groups (nominal p-values without correction for multiple testing). Some proteins related to the extracellular matrix displayed altered concentrations in the AAA group, particularly among elastin-related molecules [elastin, microfibrillar-associated protein 4 (MFAP4), lysyl oxidase]. In addition, several histones e.g. (e.g. HIST1H1E, HIST1H2BB) and other vascular cell proteins (e.g. versican, type VI collagen) were altered.

Conclusions

Our results support the notion that generalized alterations occur in the arterial tree in patients with AAA. Elastin-related proteins and histones seem to be part of such changes, however these preliminary results require replication in an independent set of specimens and validation by functional studies.

Galectin-3 and fibulin-1 in systolic heart failure - relation to glucose metabolism and left ventricular contractile reserve

Background

Heart failure (HF) patients with diabetes (DM) have an adverse prognosis and reduced functional capacity, which could be associated with cardiac fibrosis, increased chamber stiffness and reduced left ventricular (LV) contractile reserve. Galectin-3 (Gal-3) and fibulin-1 are circulating biomarkers potentially reflecting cardiac fibrosis. We hypothesize that plasma levels of Gal-3 and fibulin-1 are elevated in HF patients with DM and are associated with reduced LV contractile reserve in these patients.

Methods

A total of 155 patients with HF with reduced ejection fraction underwent a low-dose dobutamine echocardiography and blood sampling for biomarker measurements. Patients were classified according to history of DM and an oral glucose tolerance test (OGTT) as: normal glucose tolerance (NGT) (n = 70), impaired glucose tolerance (IGT) (n = 25) and DM (n = 60).

Results

Galectin-3 levels were elevated in DM patients as compared to non-diabetic patients (P = 0.02), while higher fibulin-1 levels were observed in HF patients with IGF and DM (P = 0.07). Reduced LV contractile reserve was associated with increasing Gal-3 levels (β = −0.19, P = 0.03) although, this association was attenuated after adjustment for estimated glomerular filtration rate (P = 0.66). Fibulin-1 was not associated with LV contractile reserve (P = 0.71).

Conclusions

Galectin-3 and fibulin-1 levels were elevated in HF patients with impaired glucose metabolism. However, reduced LV contractile reserve among HF patients with DM does not to have an independent impact on plasma Gal-3 and fibulin-1 levels.

Serum and vitreous fibulin-1 concentrations in patients with diabetic retinopathy

Fibulin-1, an extracellular matrix glycoprotein, is closely correlated with angiogenesis. The purpose of this investigation is to determine serum and vitreous fibulin-1 concentrations in diabetic retinopathy (DR). This cross-sectional investigation was carried out in a population of 154 diabetic patients (54 without DR, 42 with non-proliferative diabetic retinopathy (NPDR) and 58 with proliferative diabetic retinopathy (PDR)) and 49 control subjects. The diabetic group showed higher serum and vitreous fibulin-1 concentrations than the controls. Serum and vitreous fibulin-1 concentrations in PDR patients were significantly elevated compared with those in the other 3 groups. NPDR patients showed elevated levels of serum and vitreous fibulin-1 concentrations compared with patients without DR. Logistic regression analysis revealed that serum and vitreous fibulin-1 were risk factors for developing DR. Pearson correlation analysis showed that serum fibulin-1 was correlated with systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting plasma glucose and vitreous fibulin-1. Furthermore, Pearson correlation analysis showed that vitreous fibulin-1 was correlated with SBP, DBP, high-density lipoprotein cholesterol and serum fibulin-1. Serum and vitreous fibulin-1 concentrations are elevated under DR condition.

Calumenin and fibulin-1 on tumor metastasis: Implications for pharmacology

Tumor metastasis is a key cause of cancer mortality, and inhibiting migration of cancer cells is one of the major directions of anti-metastatic drug development. Calumenin and fibulin-1 are two extracellular proteins that synergistically inhibit cell migration and tumor metastasis, and could potentially be served as targets for pharmacological research of anti-metastatic drugs. This review briefly introduces the multi-function of these two proteins, and discusses the mechanism of how they regulate cell migration and tumor metastasis.