Aged muscles accumulate satellite cells with a striking decline response to damage. Although intrinsic defects in satellite cells themselves are the major contributors to aging-associated stem cell dysfunction, increasing evidence suggests that changes in the muscle-stem cell local microenvironment also contribute to aging. Here, we demonstrate that loss of the matrix metalloproteinase-10 (MMP-10) in young mice alters the composition of the muscle extracellular matrix (ECM), and specifically disrupts the extracellular matrix of the satellite cell niche. This situation causes premature features of aging in the satellite cells, contributing to their functional decline and a predisposition to enter senescence under proliferative pressure. Similarly, reduction of MMP-10 levels in young satellite cells from wild type animals induces a senescence response, while addition of the protease delays this program. Significantly, the effect of MMP-10 on satellite cell aging can be extended to another context of muscle wasting, muscular dystrophy. Systemic treatment of mdx dystrophic mice with MMP-10 prevents the muscle deterioration phenotype and reduces cellular damage in the satellite cells, which are normally under replicative pressure. Most importantly, MMP-10 conserves its protective effect in the satellite cell-derived myoblasts isolated from a Duchenne muscular dystrophy patient by decreasing the accumulation of damaged DNA. Hence, MMP-10 provides a previously unrecognized therapeutic opportunity to delay satellite cell aging and overcome satellite cell dysfunction in dystrophic muscles.

BACKGROUND AND AIMS: Peripheral arterial disease (PAD) is a leading cause of morbimortality worldwide. Lipocalin-2 (LCN2) has been associated with higher risk of amputation or mortality in PAD and might be involved in muscle regeneration. Our aim is to unravel the role of LCN2 in skeletal muscle repair and PAD. METHODS AND RESULTS: WT and Lcn2-/- mice underwent hindlimb ischemia. Blood and crural muscles were analyzed at the inflammatory and regenerative phases. At day 2, Lcn2-/- male mice, but not females, showed increased blood and soleus muscle neutrophils, and elevated circulating pro-inflammatory monocytes (p<0.05), while locally, total infiltrating macrophages were reduced (p<0.05). Moreover, Lcn2-/- soleus displayed an elevation of Cxcl1 (p<0.001), and Cxcr2 (p<0.01 in males), and a decrease in Ccl5 (p<0.05). At day 15, Lcn2 deficiency delayed muscle recovery, with higher density of regenerating myocytes (p<0.04) and arterioles (alphaSMA+, p<0.025). Reverse target prediction analysis identified miR-138-5p as a potential regulator of LCN2, showing an inverse correlation with Lcn2 mRNA in skeletal muscles (rho=-0.58, p<0.01). In vitro, miR-138-5p mimic reduced Lcn2 expression and luciferase activity in murine macrophages (p<0.05). Finally, in human serum miR-138-5p was inversely correlated with LCN2 (p¿0.001 adjusted, n=318), and associated with PAD (Odds ratio 0.634, p=0.02, adjusted, PAD n=264, control n=54). CONCLUSIONS: This study suggests a possible dual role of LCN2 in acute and chronic conditions, with a probable role in restraining inflammation early after skeletal muscle ischemia, while being associated with vascular damage in PAD, and identifies miR-138-5p as one potential post-transcriptional regulator of LCN2.

Background: Matrix metalloproteinase-10 (MMP-10) levels increase progressively starting from early diabetic kidney disease (DKD) stages. Vitamin D-3 (vitD(3)) deficit is associated with a higher risk of diabetic microangiopathy. Reduced MMP-10 expression has been observed after exposure to vitD(3). Aim: to assess how vitD(3) status is related to MMP-10 levels in patients with Type 2 diabetes (T2D). Methods: 256 patients with T2D were included in this cross-sectional study. Demographic, clinical and serum MMP-10 and 25-hydroxyvitamin D-3 (25(OH)D-3) levels were collected from each patient. The association between MMP-10 and (25(OH)D-3) levels was assessed using a correlation analysis and fitting a multivariate linear regression model. Results: Serum MMP-10 levels were inversely correlated with circulating 25(OH)D-3 (rho = -0.25; p < 0.001). In the subgroup analysis this correlation was significant in patients with DKD (rho = -0.28; p = 0.001) and in subjects with vitD(3) deficit (rho = -0.24; p = 0.005). In the regression model adjusted for kidney function, body adiposity, smoking and vitD supplementation MMP-10 levels were 68.7 pg/mL lower in patients with 25(OH)D-3 > 20 ng/mL, with respect to <= 20 ng/mL (p = 0.006). Conclusions: vitD(3) repletion status is an independent predictor of MMP-10 levels in T2D patients. Perhaps, high 25(OH)D-3 values should be targeted in these patients in order to prevent vascular complications.

Background: Intracranial hemorrhage (ICH) is one of the major devastating complications of anticoagulation. Matrix metalloproteinase (MMP) inhibition has been proposed as a novel pharmacological approach for ICH treatment. Objectives: We evaluated the effects of CM-352 (MMP-fibrinolysis inhibitor) in an experimental ICH model associated with oral anticoagulants as compared with clinically used prothrombin complex concentrate (PCC). Methods: ICH was induced by collagenase injection into the striatum of wild type (C57BL/6J) anticoagulated mice (warfarin or rivaroxaban) and Mmp10 -/- mice. Hematoma volume and neurological deficits were measured 24 hours later by diaminobenzidine staining and different behavioral tests. Circulating plasminogen activator inhibitor-1 (PAI-1) activity and interleukin-6 (IL-6) were measured in plasma samples and local inflammation was assessed by neutrophil infiltration. Finally, fibrinolytic effects of MMP-10 and rivaroxaban were evaluated by thromboelastometry and thrombin-activatable fibrinolysis inhibitor (TAFI) activation assays. Results: Only PCC reduced hemorrhage volume and improved functional outcome in warfarin-ICH, but both PCC and CM-352 treatments diminished hemorrhage volume (46%, p < 0.01 and 64%, p < 0.001, respectively) and ameliorated functional outcome in rivaroxaban-ICH. We further demonstrated that CM-352, but not PCC, decreased neutrophil infiltration in the hemorrhage area at 24 hours. The effect of CM-352 could be related to MMP-10 inhibition since Mmp10 -/- mice showed lower hemorrhage volume, better neurological score, reduced IL-6 levels and neutrophil infiltration, and increased PAI-1 after experimental ICH. Finally, we found that CM-352 reduced MMP-10 and rivaroxaban-related fibrinolytic effects in thromboelastometry and TAFI activation. Conclusion: CM-352 treatment, by diminishing MMPs and rivaroxaban-associated fibrinolytic effects, might be a novel antihemorrhagic strategy for rivaroxaban-associated ICH.

Predicting the progression of small aneurysms is a main challenge in abdominal aortic aneurysm (AAA) management. The combination of circulating biomarkers and image techniques might provide an alternative for risk stratification. We evaluated the association of plasma TAT complexes (TAT) and D-dimer with AAA severity in 3 groups of patients: group 1, without AAA (n = 52), group 2, AAA 40-50 mm (n = 51) and group 3, AAA > 50 mm (n = 50). TAT (p < 0.001) and D-dimer (p < 0.001) were increased in patients with AAA (groups 2 and 3) vs. group 1. To assess the association between baseline TAT and D-dimer concentrations, and AAA growth, aortic diameter and volume (volumetry) were measured by computed tomography angiography (CTA) in group 2 at recruitment (baseline) and 1-year after inclusion. Baseline D-dimer and TAT levels were associated with AAA diameter and volume variations at 1-year independently of confounding factors (p <= 0.044). Additionally, surgery incidence, recorded during a 4-year follow-up in group 2, was associated with larger aneurysms, assessed by aortic diameter and volumetry (p <= 0.036), and with elevated TAT levels (sub-hazard ratio 1.3, p <= 0.029), while no association was found for D-dimer. The combination of hemostatic parameters and image techniques might provide valuable tools to evaluate AAA growth and worse evolution.

Objective: Peripheral arterial disease (PAD) is the most prevalent cardiovascular (CV) condition globally. Despite the high CV risk of PAD patients, no reliable predictors of adverse clinical evolution are yet available. In this regard, previous transcriptomic analyses revealed increased expression of calprotectin (S100A8/A9) and lipocalin-2 (LCN2) in circulating extracellular vesicles (EVs) of patients with PAD. The aim of this study was to determine the prognostic value of LCN2 and calprotectin for CV risk assessment in PAD. Methods: LCN2 and the S100A9 subunit of calprotectin were examined in human femoral plaques by immunohistochemistry and qPCR. LCN2 and calprotectin were determined by ELISA in PAD (CHN cohort, n = 331, Fontaine IIeIV, serum), and PAD diagnosed by population based screening (VIVA trial, n = 413, the majority Fontaine 0eI, plasma). Patients were followed up for a mean of four years, recording the primary outcomes; CV death or amputation in the CHN cohort and CV death or major lower limb events (MALE) in the VIVA population. Secondary outcomes were all cause death or amputation, and all cause death or MALE, respectively. Results: LCN2 and S100A9 were detected in human plaques in regions rich in inflammatory cells. LCN2 and calprotectin levels were 70% and 64% lower in plasma than in serum. In the CHN cohort, high serum levels of LCN2 and calprotectin increased the risk of primary and secondary outcomes 5.6 fold (p < .001) and 1.8 fold (p = .034), respectively, after covariable adjustment. Similarly, elevated plasma levels of LCN2 and calprotectin increased by three fold the risk of primary and secondary outcomes (p <.001) in the VIVA cohort. Moreover, addition of the combined variable to basal models, considering clinically relevant risk factors, improved reclassification for the primary outcome in both cohorts (p <= .024). Conclusion: Combined assessment of the inflammatory biomarkers LCN2 and calprotectin might be useful for risk stratification in advanced and early PAD.

Age-related macular degeneration (AMD) is currently the main cause of severe visual loss among older adults in developed countries. The pathophysiology has not been clarified, but oxidative stress is believed to play a major role. Matrix metalloproteinases (MMP) may play a prominent role in several steps of the pathophysiology of AMD, especially in its neovascular form; therefore, there is of great interest in understanding their role in choroidal neovascularisation. This study aimed to elucidate the role of MMP10 in the development of choroidal neovascularisation (CNV). We have demonstrated that MMP10 was expressed by retinal pigment epithelium cells and endothelial cells of the neovascular membrane, in cell culture, mouse and human retina. MMP10 expression and activity increased under oxidative stress conditions in ARPE-19 cells. MMP10(-/-) mice developed smaller laser-induced areas of CNV. Furthermore, to exclude a systemic MMP10 imbalance in these patients, plasma MMP10 concentrations were assessed in an age- and sex-matched sample of 52 control patients and 52 patients with neovascular AMD and no significant differences were found between the groups, demonstrating that MMP10 induction is a local phenomenon. Our findings suggest that MMP10 participates in the development of choroidal neovascularisation and promotes MMP10 as a possible new therapeutic target.

NADPH oxidases (NOX) constitute the main reactive oxygen species (ROS) source in blood vessels. An oxidative stress situation due to ROS overproduction can lead into endothelial dysfunction, a molecular mechanism that precedes cardiovascular diseases (CVDs) such as atherosclerosis, myocardial infarction, and stroke. NOX5 is the last discovered member of the NOX family, studied in a lesser extent due to its absence in the rodent genome. Our objective was to describe the phenotypic alterations produced by an oxidative stress situation derived from NOX5 overexpression in an endothelial in vitro model. The in vitro model consists of the hCMEC/D3 cell line, derived from brain microvascular endothelium, infected with a recombinant NOX5-beta adenovirus. After an initial proteomic analysis, three phenotypic alterations detected in silico were studied: cell proliferation and apoptosis, general and mitochondrial metabolism, and migration capacity. NOX5 infection of hCMEC/D3 generates a functional protein and an increase in ROS production. This model produced changes in the whole cell proteome. The in silico analysis together with in vitro validations demonstrated that NOX5 overexpression inhibits proliferation and promotes apoptosis, metabolic alterations and cell migration in hCMEC/D3 cells. NOX5 overexpression in endothelial cells leads to phenotypic changes that can lead to endothelial dysfunction, the onset of atherosclerosis, myocardial infarction, and stroke.

BACKGROUND: Atherosclerosis is the main etiology of cardiovascular diseases (CVD), associated to systemic inflammation. Matrix metalloproteinases (MMPs) are related to atherosclerosis progression through the SDF1/CXCR4 axis promoting macrophages recruitment within the vascular wall. The goal was to assess new circulatory inflammatory markers in relation to atherosclerosis. METHODS: Measurement of SDF1, MMP12 and CRP in blood samples of 298 prospective patients with cardiovascular risk. To explore atherosclerosis progression, CXCR4/SDF1 axis and MMP12 expression were determined by RT-qPCR and by immunohistochemistry in the aorta of accelerated and delayed atherosclerosis mice models (Apoe-/- and Apoe-/-Mmp10-/-). RESULTS: SDF1, MMP12 and CRP were elevated in patients with clinical atherosclerosis, but after controlling by confounding factors, only SDF1 and CRP remained increased. Having high levels of both biomarkers showed 2.8-fold increased risk of presenting clinical atherosclerosis (p = 0.022). Patients with elevated SDF1, MMP12 and CRP showed increased risk of death in follow-up (HR = 3.2, 95%CI: 1.5-7.0, p = 0.004). Gene and protein expression of CXCR4 and MMP12 were increased in aortas from Apoe-/- mice. CONCLUSIONS: The combination of high circulating SDF1, MMP12 and CRP identified patients with particular inflammatory cardiovascular risk and increased mortality. SDF1/CXCR4 axis and MMP12 involvement in atherosclerosis development suggests that they could be possible atherosclerotic targets.

Background Inflammatory response plays an important role in many processes related to acute ischemic stroke (AIS). Calprotectin (S100A8/S100A9), released by monocytes and neutrophils, is a key protein in the regulation of inflammation and thrombosis. The purpose of this study is to evaluate the association of circulating calprotectin with other inflammatory biomarkers and AIS prognosis, as well as the calprotectin content in stroke thrombi. Methods Among the 748 patients treated at a comprehensive stroke center between 2015 and 2017, 413 patients with confirmed acute ischemic injury were prospectively evaluated. Patients with systemic inflammation or infection at onset were excluded. Plasma calprotectin was measured by ELISA in blood samples of AIS patients within the first 24 h. Univariate and multivariate logistic regression models were performed to evaluate its association with mortality and functional independence (FI) at 3 months (defined as modified Rankin Scale < 3) and hemorrhagic transformation (HT) after ischemic stroke. Further, S100A9 was localized by immunostaining in stroke thrombi (n = 44). Results Higher calprotectin levels were associated with 3-month mortality, HT, and lower 3-month FI. After adjusting for potential confounders, plasma calprotectin remained associated with 3-month mortality [OR (95% CI) 2.31 (1.13-4.73)]. Patients with calprotectin >= 2.26 mu g/mL were 4 times more likely to die [OR 4.34 (1.95-9.67)]. Addition of calprotectin to clinical variables led to significant improvement in the discrimination capacity of the model [0.91 (0.87-0.95) vs 0.89 (0.85-0.93); p < 0.05]. A multimarker approach demonstrated that patients with increased calprotectin, CRP, and NLR had the poorest outcome with a mortality rate of 42.3% during follow-up. S100A9 protein, as part of the heterodimer calprotectin, was present in all thrombi retrieved from AIS patients. Mean S100A9 content was 3.5% and tended to be higher in patients who died (p = 0.09). Moreover, it positively correlated with platelets (Pearson r 0.46, p < 0.002), leukocytes (0.45, p < 0.01), and neutrophil elastase (0.70, p < 0.001) thrombus content. Conclusions Plasma calprotectin is an independent predictor of 3-month mortality and provides complementary prognostic information to identify patients with poor outcome after AIS. The presence of S100A9 in stroke thrombi suggests a possible inflammatory mechanism in clot formation, and further studies are needed to determine its influence in resistance to reperfusion.