Low molecular weight Adiponectin increases the mortality risk in very old patients

Despite its beneficial role on insulin resistance and atherosclerosis, adiponectin has been frequently reported as an independent positive predictor of cardiovascular mortality. Very few information is available regarding adiponectin isoforms and mortality, in particular in advanced aging. Baseline serum levels of Total Adiponectin and its circulating isoforms (HMW-, MMW-, LMW-Adiponectin) were measured in 97 old patients (mean age: 79 years). Patients were followed up for all-cause mortality (study end-point) for an average of 76.4 ±37.3 months. A positive association was observed for LMW-Ad and all-cause mortality (HR: 1.13, 95% CI: 1.05-1,22, p: 0.002). After multivariate adjustment for age, sex and a previous history of myocardial infarction, higher levels of LMW-Ad were significantly associated with all-cause mortality (HR: 1.11, 95% CI: 1.02-1.21; p: 0.017). Interestingly neither total adiponectin neither the other two circulating isoforms (MMW- and HMW-Ad) showed any significant association with the study end-point. Our data suggest that the association between high serum adiponectin levels and increased mortality rate in elderly is contingent to an unbalanced circulating levels of adiponectin isoforms. The present results support the hypothesis that high levels of Low Molecular Weight adiponectin are a biomarker for mortality risk in very old patients

C-peptide: a predictor of cardiovascular mortality in subjects with established atherosclerotic disease

Aim: Insulin resistance and type 2 diabetes are independent risk factors for cardiovascular diseases. Levels of C-peptide are increased in these patients and its role in the atherosclerosis progression was studied in vitro and in vivo over the past years. To evaluate the possible use of C-peptide as cardiovascular biomarkers, we designed an observational study in which we enrolled patients with mono- or poly-vascular atherosclerotic disease. Methods: We recruited 431 patients with stable atherosclerosis and performed a yearly follow-up to estimate the cardiovascular and total mortality and cardiovascular events. Results: We performed a mean follow-up of 56months on 268 patients. A multivariate Cox analysis showed that C-peptide significantly increased the risk of cardiovascular mortality [Hazard Ratio: 1.29 (95% confidence interval: 1.02-1.65, p<0.03513)] after adjustment for age, sex, diabetes treatment, estimated glomerular filtration rate and known diabetes status. Furthermore, levels of C-peptide were significantly correlated with metabolic parameters and atherogenic factors. Conclusion: C-peptide was associated with cardiovascular mortality independently of known diabetes status in a cohort of patients with chronic atherosclerotic disease. Future studies using C-peptide into a reclassification approach might be undertaken to consider its potential as a cardiovascular disease biomarker

IL-6 Levels Influence 3-Month All-Cause Mortality in Frail Hospitalized Older Patients

The multidimensional prognostic index (MPI) is a sensitive and specific prognosis estimation tool that accurately predicts all-cause mortality in frail older patients. It has been validated to assess the risk of 1-month to 2-year mortality in frail older patients during hospitalization and after hospital discharge. However, whether the MPI is a valid prognostic tool for follow-up periods of different lengths remains to be validated. To this end, we followed up 80 hospitalized patients (female=37, male 43) at least 75 years of age (mean age=82.6±4.4, range=75-94 years) to assess the 3-month all-cause mortality (mean follow-up=61.0 ± 31.7 months [range 4-90 days]). Accordingly, patients were subdivided into low (MPI-1, score 0-0.33), moderate (MPI-2, score 0.34-0.66) and high (MPI-3, score 0.67-1) mortality risk classes. Moreover, baseline biochemical, inflammatory and metabolic parameters, as well as anamnestic and clinical characteristics, were obtained. Although the MPI-3 score was significantly associated with 3-month all-cause mortality in univariate analysis (HR=5.79, 95%CI=1.77-18.92, p=0.004), a multivariate model indicated that only low albumin (HR=0.33, 95%CI=0.16-0.68, p=0.003) and high IL6 (HR=1.01, 95%CI=1.00-1.02, p=0.010) levels were significantly associated with 3-month all-cause mortality. In conclusion, we suggest that measurement of IL6 as well as albumin, rather than the MPI score, may help in providing tailored therapeutic interventions to decrease short term mortality in older hospitalized individuals

High Sensitivity C-Reactive Protein Increases the Risk of Carotid Plaque Instability in Male Dyslipidemic Patients

Background: The aim of this study was to evaluate how the high sensitivity C-reactive protein (hs-CRP) values influence the risk of carotid plaque instability in association with other cardiovascular risk factors. Methods: One hundred and fifty-six carotid plaques from both symptomatic and asymptomatic patients requiring surgical carotid endarterectomy were retrospectively collected. According to the modified American Heart Association, atherosclerosis plaques have been histologically distinguished into unstable and stable. The following anamnestic and hematochemical data were also considered: age, gender, hypertension, diabetes mellitus, smoking habit, therapy, low-density lipoprotein (LDL)-C, kidney failure and hs-CRP. Results: The results of our study clearly show that high levels of hs-CRP significantly increase the carotid plaque instability in dyslipidemic patients. Specifically, a 67% increase of the risk of carotid plaque instability was observed in patients with high LDL-C. Therefore, the highest risk was observed in male dyslipidemic patients 2333 (95% CI 0.73–7.48) and in aged female patients 2713 (95% CI 0.14–53.27). Discussion: These data strongly suggest a biological relationship between the hs-CRP values and the alteration of lipidic metabolism mostly in male patients affected by carotid atherosclerosis. The measurement of hs-CRP might be useful as a potential screening tool in the prevention of atheroscletotic disease

ITCH E3 ubiquitin ligase downregulation compromises hepatic degradation of branched-chain amino acids

Objective: Metabolic syndrome, obesity, and steatosis are characterized by a range of dysregulations including defects in ubiquitin ligase tagging proteins for degradation. The identification of novel hepatic genes associated with fatty liver disease and metabolic dysregulation may be relevant to unravelling new mechanisms involved in liver disease progression METHODS: Through integrative analysis of liver transcriptomic and metabolomic obtained from obese subjects with steatosis, we identified itchy E ubiquitin protein ligase (ITCH) as a gene downregulated in human hepatic tissue in relation to steatosis grade. Wild-type or ITCH knockout mouse models of non-alcoholic fatty liver disease (NAFLD) and obesity-related hepatocellular carcinoma were analyzed to dissect the causal role of ITCH in steatosis RESULTS: We show that ITCH regulation of branched-chain amino acids (BCAAs) degradation enzymes is impaired in obese women with grade 3 compared with grade 0 steatosis, and that ITCH acts as a gatekeeper whose loss results in elevation of circulating BCAAs associated with hepatic steatosis. When ITCH expression was specifically restored in the liver of ITCH knockout mice, ACADSB mRNA and protein are restored, and BCAA levels are normalized both in liver and plasma CONCLUSIONS: Our data support a novel functional role for ITCH in the hepatic regulation of BCAA metabolism and suggest that targeting ITCH in a liver-specific manner might help delay the progression of metabolic hepatic diseases and insulin resistance

Genetic deficiency of indoleamine 2,3-dioxygenase promotes gut microbiota-mediated metabolic health.

The association between altered gut microbiota, intestinal permeability, inflammation and cardiometabolic diseases is becoming increasingly clear but remains poorly understood1,2. Indoleamine 2,3-dioxygenase is an enzyme induced in many types of immune cells, including macrophages in response to inflammatory stimuli, and catalyzes the degradation of tryptophan along the kynurenine pathway. Indoleamine 2,3-dioxygenase activity is better known for its suppression of effector T cell immunity and its activation of regulatory T cells3,4. However, high indoleamine 2,3-dioxygenase activity predicts worse cardiovascular outcome5-9 and may promote atherosclerosis and vascular inflammation6, suggesting a more complex role in chronic inflammatory settings. Indoleamine 2,3-dioxygenase activity is also increased in obesity10-13, yet its role in metabolic disease is still unexplored. Here, we show that obesity is associated with an increase of intestinal indoleamine 2,3-dioxygenase activity, which shifts tryptophan metabolism from indole derivative and interleukin-22 production toward kynurenine production. Indoleamine 2,3-dioxygenase deletion or inhibition improves insulin sensitivity, preserves the gut mucosal barrier, decreases endotoxemia and chronic inflammation, and regulates lipid metabolism in liver and adipose tissues. These beneficial effects are due to rewiring of tryptophan metabolism toward a microbiota-dependent production of interleukin-22 and are abrogated after treatment with a neutralizing anti-interleukin-22 antibody. In summary, we identify an unexpected function of indoleamine 2,3-dioxygenase in the fine tuning of intestinal tryptophan metabolism with major consequences on microbiota-dependent control of metabolic disease, which suggests indoleamine 2,3-dioxygenase as a potential therapeutic target

TIMP3: un nuovo biomarcatore di aterosclerosi nel Diabete Mellito di tipo 2: studi in vivo ed in vitro

Nei pazienti affetti da Diabete Mellito di Tipo 2 l’aterosclerosi è fortemente accelerata da meccanismi ancora oggi sconosciuti. Il nostro gruppo recentemente ha identificato l’Inibitore Tissutale delle Metalloproteinasi 3 (TIMP3), che è l’inibitore endogeno dell’enzima TNF Converting Enzyme (TACE), anche chiamato A Disintegrin and Metalloproteasi Domain 17 (ADAM17) e di altre MetalloProteasi di Matrice (MMP), come un gene favorente lo sviluppo di insulino resistenza e infiammazione vascolare nel topo. Abbiamo quindi ipotizzato che un’aumentata attività del sistema proteolitico di membrana extracellulare, dovuta ad una alterata regolazione della diade ADAM17/TIMP3, possa essere un fattore comune allo sviluppo e progressione dell’aterosclerosi, dell’insulino resistenza e del diabete. Ulteriore scopo di questo lavoro è valutare l’associazione di TIMP3 con l’aterosclerosi in pazienti affetti da Diabete Mellito di Tipo 2 (DM2) ed identificare fattori in grado di regolare l’espressione di TIMP3. I substrati solubili circolanti di ADAM17/TACE, quali sICAM-1, sVCAM-1, sIL6R, sCXCL16 e sTNFR1, sono stati analizzati nei sieri di soggetti sani di controllo (CT, n=70), pazienti con Aterosclerosi Carotidea (CAR-Ats, n=35) e pazienti con Coronaropatia (CAD, n=170). Inoltre abbiamo valutato i livelli di espressione di ADAM10/17, MMP9, TIMP1/2/3/4 in placche aterosclerotiche carotidee umane (n=60) prelevate da pazienti con e senza diabete sottoposti ad Endoarteriectomia carotidea. Cellule muscolari lisce vascolari umane esposte a diversi stimoli metabolici sono state utilizzate per identificare i regolatori dell’espressone di Timp3. Il silenziamento genico di SirT1 mediante small interference RNA (siRNA), SirT1 cDNA e un vettore reporter per il promotore del gene TIMP3 sono stati usati per studiare la regolazione dell’espressione di TIMP3 da parte di SirT1. In questo lavoro abbiamo riscontrato che, fra i substrati solubili di ADAM17/TACE, sCXCL16, sICAM-1 e sVCAM1 sono differentemente e significativamente aumentati a seconda della localizzazione della patologia vascolare aterosclerotica e dell’alterazione del metabolismo glucidico. Abbiamo inoltre mostrato che nelle placche aterosclerotiche carotidee umane i livelli di espressione di TIMP3 sono significativamente ridotti nei soggetti con diabete mellito di tipo 2 con un conseguente aumento dell’attività di ADAM17/TACE e MMP9. La ridotta espressione di TIMP3 è stata associata in vivo ai livelli di SirT1. Nelle cellule muscolari lisce vascolari umane, l’inibizione dell’attività e dei livelli di SirT1 determina una riduzione dell’espressione di TIMP3, mentre una sovra-espressione di SirT1 aumenta l’attività del promotore di TIMP3. In conclusione, i nostri dati suggeriscono che il sistema proteolitico di membrana è gradualmente attivato in soggetti con differente localizzazione della patologia aterosclerotica. Inoltre nelle placche aterosclerotiche di soggetti con il diabete mellito di tipo 2 la deregolazione dell’attività di ADAM17/TACE e delle MMP9 è correlata con un’inadeguata espressione di TIMP3 SirT1-dipendente. Gli studi effettuati su cellule vascolari confermano il ruolo di Sirt1 nel modulare l’espressione di TIMP3.Atherosclerosis is accelerated in patients with Type 2 Diabetes Mellitus (DM2) by unknown mechanisms. We identified Tissue Inhibitor of Metalloproteinase 3 (TIMP3), the endogenous inhibitor of A Disintegrin and Metalloprotease Domain 17 (ADAM17) and other Matrix MetalloProteinase (MMP), as a gene modifier for insulin resistance and vascular inflammation in mice. Therefore we hypothesized that an increased activity of the ectodomain shedding process, due to a dysregulation of ADAM17/Timp3 dyad, may be a common factor linking progression of atherosclerosis to insulin resistance and diabetes. Here we also tested TIMP3 association with atherosclerosis in patients with type 2 diabetes mellitus (DM2) and identified Sirtuin 1 (SirT1) as a major regulator of TIMP3 expression. ADAM17 substrates, such as soluble (s)ICAM-1, sVCAM-1, sIL6R, sCXCL16 and sTNFR1, were analyzed in serum from healthy subjects (CT, n=70), patients with Carotid Atherosclerosis (CAR-ATS, n=35) and patients with Coronary Artery Disease (CAD, n=170). Moreover we investigated ADAM10/17, MMP9, TIMP1/2/3/4 expression levels in human carotid atherosclerotic plaques (n=60) from subjects with and without diabetes. Human Vascular Smooth Muscle cells exposed to several metabolic stimuli were used to identify regulators of Timp3 expression. SirT1 small interference RNA (siRNA), cDNA and TIMP3 promoter gene reporter were used to study SirT1 dependent regulation of TIMP3. We found that, among soluble ADAM17 substrates, sCXCL16, sICAM-1 and sVCAM1 were differently and significantly increased according to location of vascular disease and impairment of glucose metabolism. We showed that in human carotid atherosclerotic plaques TIMP3 was significantly reduced in subjects with DM2 leading to ADAM17 and MMP9 overactivity. Reduced expression of TIMP3 was associated in vivo to SirT1 levels. In smooth muscle cells, inhibition of SirT1 activity and levels reduced TIMP3 expression, while SirT1 overexpression increased TIMP3 promoter activity. In conclusion, our data suggest that the ectodomain shedding process is gradually activated in patients with different location of atherosclerotic disease. Moreover in atherosclerotic plaques from subjects with Type 2 diabetes the deregulation of ADAM17 and MMP9 activities is related to inadequate expression of TIMP3 via SirT1. Studies in vascular cells confirmed the role of SirT1 in tuning TIMP3 expression

Carotid plaque unstability is not related to quantity but to elemental composition of calcification

Background and aims: Recent studies highlighted the role of calcification processes in the clinical progression of chronic cardiovascular diseases. In this study we investigated the relationship between the chemical composition of calcification and atherosclerotic plaque stability in carotid arteries. Methods and results: To this end, we characterized the calcification on 229 carotid plaques, by morphology, immunohistochemistry, transmission electron microscopy and energy dispersive X-ray microanalysis. Plaques were classified into two categories: unstable and stable. No significant differences were found in the incidence of the various risk factors between patients with and without carotid calcification, with the exception of diabetes. The energy dispersive X-ray microanalysis allowed us to identify two types of calcium salts in the atheromatous plaques, hydroxyapatite (HA) and calcium oxalate (CO). Our results showed that calcification is a common finding in carotid plaques, being present in 77.3% of cases, and the amount of calcium is not a factor of vulnerability. Noteworthy, we observed an association between HA calcification and unstable plaques. On the contrary, CO calcifications were mainly detected in stable plaques. Conclusions: The presence of different types of calcification in atheromatous plaques may open new perspectives in understanding the molecular mechanisms of atheroma formation and plaque instability