Francesca Martini

The recovery of platelet cyclooxygenase activity explains interindividual variability in responsiveness to low-dose aspirin in patients with and without diabetes

See also Lordkipanidze M, Harrison P. Aspirin twice a day keeps new COX‐1 at bay. This issue, pp 1217–9.

Effects of GLP-1 on Forearm Vasodilator Function and Glucose Disposal During Hyperinsulinemia in the Metabolic Syndrome

OBJECTIVE Patients with the metabolic syndrome (MetS) have impaired insulin-induced enhancement of vasodilator responses. The incretin hormone glucagon-like peptide 1 (GLP-1), beyond its effects on blood glucose, has beneficial actions on vascular function. This study, therefore, aimed to assess whether GLP-1 affects insulin-stimulated vasodilator reactivity in patients with the MetS. RESEARCH DESIGN AND METHODS Forearm blood flow responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were assessed in MetS patients before and after the addition of GLP-1 to an intra-arterial infusion of saline (n = 5) or insulin (n = 5). The possible involvement of oxidative stress in the vascular effects of GLP-1 in this setting was investigated by infusion of vitamin C (n = 5). The receptor specificity of GLP-1 effect during hyperinsulinemia was assessed by infusing its metabolite GLP-1(9-36) (n = 5). The metabolic actions of GLP-1 were also tested by analyzing forearm glucose disposal during hyperinsulinemia (n = 5). RESULTS In MetS patients, GLP-1 enhanced endothelium-dependent and -independent responses to ACh and SNP, respectively, during hyperinsulinemia (P < 0.001 for both), but not during saline (P > 0.05 for both). No changes in vasodilator reactivity to ACh and SNP were seen after GLP-1 was added to insulin and vitamin C (P > 0.05 for both) and after GLP-1(9-36) was given during hyperinsulinemia (P > 0.05 for both). Also, GLP-1 did not affect forearm glucose extraction and uptake during hyperinsulinemia (P > 0.05 for both). CONCLUSIONS In patients with the MetS, GLP-1 improves insulin-mediated enhancement of endothelium-dependent and -independent vascular reactivity. This effect may be influenced by vascular oxidative stress and is possibly exerted through a receptor-mediated mechanism.

Association Between Osteoprotegerin G1181C and T245G Polymorphisms and Diabetic Charcot Neuroarthropathy: A case-control study

OBJECTIVE Charcot neuroarthropathy is a disabling complication of diabetes. Although its pathogenesis remains unknown, we suppose that genetics may play a relevant role. RESEARCH DESIGN AND METHODS We performed a case-control study with 59 subjects with diabetic Charcot neuroarthropathy (Ch group), 41 with diabetic neuropathy without Charcot neuroarthropathy (ND group), and 103 healthy control subjects (H group) to evaluate the impact of two single nucleotide polymorphisms (SNPs) of the osteoprotegerin gene (G1181C and T245G) on the risk of Charcot neuroarthropathy. RESULTS Regarding the SNPs of G1181C, we found a significant linkage between the G allele and Charcot neuroarthropathy (Ch vs. ND, odds ratio [OR] 2.32 [95% CI 1.3–4.1], P = 0.006; Ch vs. H, 2.10 [1.3–3.3], P = 0.002; and ND vs. H, 0.90 [0.7–1.9], P = 0.452); similarly, we found a linkage with the G allele of T245G (Ch vs. ND, 6.25 [2.2–19.7], P < 0.001; Ch vs. H, 3.56 [1.9–6.7], P = 0.001; and ND vs. H, 0.54 [0.6–5.7], P = 0.304), supporting a protective role for the allele C and T, respectively. For this reason we investigated the frequency of the protective double homozygosis CC + TT (7% in Ch) that was significantly lower in Ch compared with H (0.18 [0.06–0.5], P = 0.002) and with ND (0.17 [0.05–0.58], P = 0.006), whereas there was no difference between H and ND (1.05 [0.43–2.0], P = 0.468). In a multivariate logistic backward regression model, only weight and the lack of CC and TT genotypes were independently associated with the presence of Charcot neuroarthropathy. CONCLUSIONS This is the first study that shows an association between genetic regulation of bone remodeling and Charcot neuroarthropathy.

Combined atherogenic effects of celiac disease and type 1 diabetes mellitus

OBJECTIVEnPrevious studies have shown a high cardiovascular risk in patients with autoimmune diseases, such as type 1 diabetes mellitus (T1DM). Conversely, few data are available about patients with celiac disease (CD). The aim of our study was to assess carotid intima-media thickness (c-IMT), in patients with T1DM, CD or both (T1DM+CD) as compared with age- and sex-matched healthy individuals (H).nnnMETHODSnWe enrolled 120 patients, 30 with T1DM, 30 with CD, 30 with T1DM+CD and 30 H. Clinical, metabolic and anthropometric data were collected. All T1DM patients were on insulin while all CD patients were on a gluten-free diet. c-IMT was evaluated by high frequency linear digital ultrasound.nnnRESULTSnc-IMT was significantly greater in patients with T1DM+CD than in patients with T1DM or CD (P<0.001 for both), while no difference was found between T1DM and CD. Moreover, c-IMT was greater in CD than in H (P<0.001). Glycemic control and disease duration were similar between T1DM+CD and T1DM. Lipid and anthropometric parameters were similar among groups. Furthermore, in a pooled multivariate analysis, only age and disease type were significantly correlated with c-IMT (P<0.001 for both).nnnCONCLUSIONnOur study demonstrates that celiac patients have greater c-IMT as compared with healthy individuals. Thus, non-invasive monitoring of c-IMT in CD might be useful in preventing cardiovascular disease. Moreover, patients with T1DM+CD show more severe subclinical atherosclerosis as compared with those presenting T1DM or CD only, suggesting that the association of these autoimmune diseases might accelerate the atherosclerotic process.

Role of asymmetric-dimethyl-L-arginine (ADMA) and nitrite/nitrate (NOx) in the pathogenesis of oxidative stress in female subjects with uncomplicated type 1 diabetes mellitus.

AIMSnTo explore the role of asymmetric-dimethyl-L-arginine (ADMA), an endogenous nitric oxide synthetases (NOS) inhibitor, and nitrite/nitrate (NOx) in the pathogenesis of oxidative stress in early stages of type 1 diabetes mellitus.nnnMETHODSnWe measured in 99 female subjects with uncomplicated type 1 diabetes (duration disease <10 years) and in 44 sex-matched controls (comparable for age, smoking habit, diet and physical activity) plasma levels of NOx, glycosylated haemoglobin (HbA1c), glucose, uric acid, total cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides and serum ADMA.nnnRESULTSnType 1 diabetic subjects have higher levels of glycemia, HbA1c, LDL cholesterol and NOx, but lower ADMA and serum uric acid (UA), compared with the control group; no further differences were found. A significant linear and inverse correlation was found between NOx and ADMA levels (R(2)=0.237, p<0.001).nnnCONCLUSIONSnThis study suggests a reduced ADMA inhibition of NOS as possible mechanism involved in the pathogenesis of oxidative stress in female subjects with a short duration and uncomplicated type 1 diabetes.

Adaptive immunity, inflammation, and cardiovascular complications in type 1 and type 2 diabetes mellitus.

Diabetes mellitus (DM) is a pandemics that affects more than 170 million people worldwide, associated with increased mortality and morbidity due to coronary artery disease (CAD). In type 1 (T1) DM, the main pathogenic mechanism seems to be the destruction of pancreatic β-cells mediated by autoreactive T-cells resulting in chronic insulitis, while in type 2 (T2) DM primary insulin resistance, rather than defective insulin production due to β-cell destruction, seems to be the triggering alteration. In our study, we investigated the role of systemic inflammation and T-cell subsets in T1- and T2DM and the possible mechanisms underlying the increased cardiovascular risk associated with these diseases.

Association Between Osteoprotegerin G1181C and T245G Polymorphisms And Charcot Diabetic Neuroarthropathy: a case – control study

OBJECTIVE Charcot neuroarthropathy is a disabling complication of diabetes. Although its pathogenesis remains unknown, we suppose that genetics may play a relevant role. RESEARCH DESIGN AND METHODS We performed a case-control study with 59 subjects with diabetic Charcot neuroarthropathy (Ch group), 41 with diabetic neuropathy without Charcot neuroarthropathy (ND group), and 103 healthy control subjects (H group) to evaluate the impact of two single nucleotide polymorphisms (SNPs) of the osteoprotegerin gene (G1181C and T245G) on the risk of Charcot neuroarthropathy. RESULTS Regarding the SNPs of G1181C, we found a significant linkage between the G allele and Charcot neuroarthropathy (Ch vs. ND, odds ratio [OR] 2.32 [95% CI 1.3–4.1], P = 0.006; Ch vs. H, 2.10 [1.3–3.3], P = 0.002; and ND vs. H, 0.90 [0.7–1.9], P = 0.452); similarly, we found a linkage with the G allele of T245G (Ch vs. ND, 6.25 [2.2–19.7], P < 0.001; Ch vs. H, 3.56 [1.9–6.7], P = 0.001; and ND vs. H, 0.54 [0.6–5.7], P = 0.304), supporting a protective role for the allele C and T, respectively. For this reason we investigated the frequency of the protective double homozygosis CC + TT (7% in Ch) that was significantly lower in Ch compared with H (0.18 [0.06–0.5], P = 0.002) and with ND (0.17 [0.05–0.58], P = 0.006), whereas there was no difference between H and ND (1.05 [0.43–2.0], P = 0.468). In a multivariate logistic backward regression model, only weight and the lack of CC and TT genotypes were independently associated with the presence of Charcot neuroarthropathy. CONCLUSIONS This is the first study that shows an association between genetic regulation of bone remodeling and Charcot neuroarthropathy.

When Early Experiences Build a Wall to Others’ Emotions: An Electrophysiological and Autonomic Study

Facial expression of emotions is a powerful vehicle for communicating information about others’ emotional states and it normally induces facial mimicry in the observers. The aim of this study was to investigate if early aversive experiences could interfere with emotion recognition, facial mimicry, and with the autonomic regulation of social behaviors. We conducted a facial emotion recognition task in a group of “street-boys” and in an age-matched control group. We recorded facial electromyography (EMG), a marker of facial mimicry, and respiratory sinus arrhythmia (RSA), an index of the recruitment of autonomic system promoting social behaviors and predisposition, in response to the observation of facial expressions of emotions. Results showed an over-attribution of anger, and reduced EMG responses during the observation of both positive and negative expressions only among street-boys. Street-boys also showed lower RSA after observation of facial expressions and ineffective RSA suppression during presentation of non-threatening expressions. Our findings suggest that early aversive experiences alter not only emotion recognition but also facial mimicry of emotions. These deficits affect the autonomic regulation of social behaviors inducing lower social predisposition after the visualization of facial expressions and an ineffective recruitment of defensive behavior in response to non-threatening expressions.

The Oxidative Modification of Von Willebrand Factor Is Associated with Thrombotic Angiopathies in Diabetes Mellitus

The thrombogenic activity of Von Willebrand factor (VWF) is proportional to its molecular size and inversely related to its proteolysis by ADAMTS-13. Oxidation of VWF severely impairs its proteolysis by the metalloprotease. This study was aimed at assessing in patients with type 1 and type 2 diabetes whether protein carbonyls, marker of oxidative stress, are associated with both the level and oxidation status of VWF as well as with micro- and macroangiopathic complications. Eighty-three diabetic patients (41 type 1 and 42 type 2 diabetic subjects) and their respective eighty-three healthy controls were studied after verifying the availability, through institutional databases, of clinical biochemistry records spanning at least 3 years. VWF and protein carbonyls were measured by immunoassays, whereas VWF multimers were studied by SDS-agarose gel electrophoresis. Type 2 diabetic subjects had higher levels of VWF antigen (VWF:ag), VWF activity (VWF:act) and plasma proteins’ carbonyls compared to both their controls and type 1 diabetic subjects. Moreover, high molecular weight VWF multimers and specific VWF-bound carbonyls were significantly increased in subjects with micro- and macro-angiopathic complications. In both type 1 and type 2 diabetic subjects, ADAMTS-13 activity was in the normal range. In a multivariable analysis, only VWF-bound carbonyls were significantly associated with any form of thrombotic angiopathy in the entire group of T1- and T2 diabetic patients. These data provide first evidence that not only high VWF levels but also its oxidation status and the presence of high molecular weight VWF multimers that are not observed in SDS-agarose gel electrophoresis of normal subjects are associated with thrombotic angiopathies in diabetes mellitus. These findings may help identify diabetic patients particularly at risk for these complications and elucidate a new pathophysiological mechanism of thrombotic angiopathies in this clinical setting.

Impact of Childhood Maltreatment on the Recognition of Facial Expressions of Emotions.

The development of the explicit recognition of facial expressions of emotions can be affected by childhood maltreatment experiences. A previous study demonstrated the existence of an explicit recognition bias for angry facial expressions among a population of adolescent Sierra Leonean street-boys exposed to high levels of maltreatment. In the present study, the recognition bias for angry facial expressions was investigated in a younger population of street-children and age-matched controls. Participants performed a forced-choice facial expressions recognition task. Recognition bias was measured as participants’ tendency to over-attribute anger label to other negative facial expressions. Participants’ heart rate was assessed and related to their behavioral performance, as index of their stress-related physiological responses. Results demonstrated the presence of a recognition bias for angry facial expressions among street-children, also pinpointing a similar, although significantly less pronounced, tendency among controls. Participants’ performance was controlled for age, cognitive and educational levels and for naming skills. None of these variables influenced the recognition bias for angry facial expressions. Differently, a significant effect of heart rate on participants’ tendency to use anger label was evidenced. Taken together, these results suggest that childhood exposure to maltreatment experiences amplifies children’s “pre-existing bias” for anger labeling in forced-choice emotion recognition task. Moreover, they strengthen the thesis according to which the recognition bias for angry facial expressions is a manifestation of a functional adaptive mechanism that tunes victim’s perceptive and attentive focus on salient environmental social stimuli.