Deficiency of Peptidylglycine-alpha-amidating Monooxygenase, a Cause of Sarcopenic Diabetes Mellitus.

CONTEXT: Peptidylglycine-α-amidating monooxygenase (PAM) is a critical enzyme in the endocrine system responsible for activation, by amidation, of bioactive peptides. OBJECTIVE: To define the clinical phenotype of carriers of genetic mutations associated with impaired PAM-amidating activity (PAM-AMA). DESIGN: We used genetic and phenotypic data from cohort studies: the Malmö Diet and Cancer (MDC; 1991-1996; reexamination in 2002-2012), the Malmö Preventive Project (MPP; 2002-2006), and the UK Biobank (UKB; 2012). SETTING: Exome-wide association analysis was used to identify loss-of-function (LoF) variants associated with reduced PAM-AMA and subsequently used for association with the outcomes. PATIENTS OR OTHER PARTICIPANTS: This study included n∼4500 participants from a subcohort of the MDC (MDC-Cardiovascular cohort), n∼4500 from MPP, and n∼300,000 from UKB. MAIN OUTCOME MEASURES: Endocrine-metabolic traits suggested by prior literature, muscle mass, muscle function, and sarcopenia. RESULTS: Two LoF variants in the PAM gene, Ser539Trp (minor allele frequency: 0.7%) and Asp563Gly (5%), independently contributed to a decrease of 2.33 [95% confidence interval (CI): 2.52/2.15; P = 2.5E-140] and 0.98 (1.04/0.92; P = 1.12E-225) SD units of PAM-AMA, respectively. The cumulative effect of the LoF was associated with diabetes, reduced insulin secretion, and higher levels of GH and IGF-1. Moreover, carriers had reduced muscle mass and function, followed by a higher risk of sarcopenia. Indeed, the Ser539Trp mutation increased the risk of sarcopenia by 30% (odds ratio 1.31; 95% CI: 1.16/1.47; P = 9.8E-06), independently of age and diabetes. CONCLUSION: PAM-AMA genetic deficiency results in a prediabetic sarcopenic phenotype. Early identification of PAM LoF carriers would allow targeted exercise interventions and calls for novel therapies that restore enzymatic activity.

Lifestyle and genetic risk of chronic liver disease in metabolically healthy and unhealthy individuals from the general population.

Background & Aims: It is unclear to what extent lifestyle and genetic factors affect the incidence of chronic liver disease (CLD) in the general population and if lifestyle affects CLD independently of underlying cardiometabolic perturbations and genetic predisposition. Methods: We examined 27,991 men and women aged 44-73 years from the Malmö Diet and Cancer Study recruited between 1991-1996 and followed until the end of 2020 using registry linkage (median follow-up time 25.1 years; 382 incident first-time CLD events). Associations between cardiometabolic factors, polygenic risk scores (PRSs), and lifestyle factors in relation to CLD were examined using multivariable Cox proportional hazards regression models. Results: The incidence of CLD increased with number of cardiometabolic risk factors (the hazard ratio per each additional cardiometabolic risk factor was 1.33; 95% CI 1.21-1.45; p = 5.1 x 10-10). Two novel PRSs for metabolic dysfunction-associated steatotic liver disease and a PRS for cirrhosis were associated with higher risk of CLD but provided marginal predictive utility on top of other risk factors and compared to the PNPLA3 rs738409 genetic variant. An unhealthy lifestyle (high alcohol intake, current smoking, physical inactivity and unhealthy diet) markedly increased the risk of CLD (hazard ratio 3.97, 95% CI 2.59-6.10). Observed associations between examined lifestyle factors and CLD were largely independent of cardiometabolic perturbations and polygenic risk. Conclusions: We confirmed the importance of cardiometabolic dysfunction in relation to risk of CLD in the general population. Lifestyle risk factors were shown to be independently associated with CLD and added predictive information on top of cardiometabolic risk factors. Information on the polygenic risk of liver disease does not currently improve the prediction of CLD in the general population. Impact and implications: This large population-based prospective study suggests largely independent roles of cardiometabolic, lifestyle, and genetic risk factors in the development of chronic liver disease. Findings strengthen the evidence base for a beneficial effect of modification of high-risk lifestyle behaviors in the primary prevention of chronic liver disease in the general population.

Comparison of Performance in the Six-Minute Walk Test (6MWT) between Overweight/Obese and Normal-Weight Children and Association with Haemodynamic Parameters: A Cross-Sectional Study in Four Primary Schools.

Physical activity plays a pivotal role in preventing obesity and cardiovascular risks. The six-minute walk test (6MWT) is a tool to assess functional capacity and predict cardiovascular events. The aim of this cross-sectional study was to compare the performance and haemodynamic parameters before and after a 6MWT between obese/overweight vs. normal-weight children (average age 8.7 ± 0.7 years) participating in a project involving four primary schools in South Verona (Italy). Validated questionnaires for physical activity and diet, as well as blood drops, were collected. Overweight or obese children (OW&OB; n = 100) covered a shorter 6MWT distance compared to normal-weight children (NW, n = 194). At the test's conclusion, the OW&OB group exhibited a higher Rate Pulse Product (RPP = Systolic Blood Pressure × Heart Rate) as compared to the NW. Body Mass Index, waist-to-height ratio, fat mass by electrical impedance, and trans fatty acids showed direct correlations with pre and post-test haemodynamic parameters, such as RPP, and inverse correlations with oxygen saturation. OW&OB children demonstrated lower performance in this low-intensity exercise test, along with an elevated haemodynamic response. Excess fat in childhood can be considered a risk factor for haemodynamic stress, with potential deleterious consequences later in life. Efforts should be initiated early to break this cycle.

Caffeine Intake, Plasma Caffeine Level, and Kidney Function: A Mendelian Randomization Study.

Caffeine is a psychoactive substance widely consumed worldwide, mainly via sources such as coffee and tea. The effects of caffeine on kidney function remain unclear. We leveraged the genetic variants in the CYP1A2 and AHR genes via the two-sample Mendelian randomization (MR) framework to estimate the association of genetically predicted plasma caffeine and caffeine intake on kidney traits. Genetic association summary statistics on plasma caffeine levels and caffeine intake were taken from genome-wide association study (GWAS) meta-analyses of 9876 and of >47,000 European ancestry individuals, respectively. Genetically predicted plasma caffeine levels were associated with a decrease in estimated glomerular filtration rate (eGFR) measured using either creatinine or cystatin C. In contrast, genetically predicted caffeine intake was associated with an increase in eGFR and a low risk of chronic kidney disease. The discrepancy is likely attributable to faster metabolizers of caffeine consuming more caffeine-containing beverages to achieve the same pharmacological effect. Further research is needed to distinguish whether the observed effects on kidney function are driven by the harmful effects of higher plasma caffeine levels or the protective effects of greater intake of caffeine-containing beverages, particularly given the widespread use of drinks containing caffeine and the increasing burden of kidney disease.

Subclinical Target Organ Damage in a Sample of Children with Autosomal Dominant Polycystic Kidney Disease: A Pilot Study.

Background and Objectives: Hypertension and vascular damage can begin in adolescents affected by Autosomal Dominant Polycystic Kidney Disease (ADPKD). This study aimed to evaluate markers of vascular damage and left ventricular geometry in a sample of children with ADPKD. Materials and Methods: Several vascular measurements were obtained: ambulatory blood pressure monitoring (ABPM), carotid intima-media thickness (cIMT), carotid distensibility coefficient (cDC), pulse wave velocity (PWV), and echocardiographic measurements (relative wall thickness (RWT) and left ventricular mass index (LVMI)). Results: Eleven ADPKD children were recruited (four females and seven males, mean age 9.5 ± 3.2 years). Four children were hypertensive at the ABPM, five were normotensive, and for two ABPM was not available. RWT was tendentially high (mean 0.47 ± 0.39). Eight patients had concentric cardiac remodeling, while one patient had cardiac hypertrophy. cIMT was above the 95° percentile for sex and height in 80% of the children (0.5 ± 0.005 mm). The average PWV and cDC were between the normal range (5.5 ± 4.6 m/s and 89.6 ± 16.1 × 10-3/KPa, respectively). We observed a positive correlation between the PWV and RWT (r = 0.616; p = 0.044) and a negative correlation between cDC and RWT (r = -0.770; p = 0.015). Cardiovascular damages (cIMT > 95° percentile) were found in normotensive patients. Conclusions: Increased RWT and high cIMT, indicating subclinical organ damage, are already present in ADPKD children. RWT was significantly correlated to that of cDC and PWV, implying that vascular stiffening is associated with cardiac remodeling. None of the children had an alteration in renal function. Subclinical cardiovascular damage preceded the decline in glomerular filtration rate.

Renoprotective effects of genetically proxied fibroblast growth factor 21: Mendelian randomization, proteome-wide and metabolome-wide association study.

BACKGROUND: Fibroblast growth factor 21 (FGF21) has demonstrated efficacy for reducing liver fat and reversing non-alcoholic steatohepatitis in phase 2 clinical trials. It is also postulated to have anti-fibrotic effects and therefore may be amenable to repurposing for the prevention and treatment of chronic kidney disease (CKD). METHODS: We leverage a missense genetic variant, rs739320 in the FGF21 gene, that associates with magnetic resonance imaging-derived liver fat as a clinically validated and biologically plausible instrumental variable for studying the effects of FGF21 analogs. Performing Mendelian randomization, we ascertain associations between instrumented FGF21 and kidney phenotypes, cardiometabolic disease risk factors, as well as the circulating proteome (Somalogic, 4907 aptamers) and metabolome (Nightingale platform, 249 metabolites). RESULTS: We report consistent renoprotective associations of genetically proxied FGF21 effect, including higher glomerular filtration rates (p = 1.9 × 10-4), higher urinary sodium excretion (p = 5.1 × 10-11), and lower urine albumin-creatinine ratio (p = 3.6 × 10-5). These favorable effects translated to lower CKD risk (odds ratio per rs739320 C-allele, 0.96; 95%CI, 0.94-0.98; p = 3.2 × 10-4). Genetically proxied FGF21 effect was also associated with lower fasting insulin, waist-to-hip ratio, blood pressure (systolic and diastolic BP, p < 1.0 × 10-07) and blood lipid (low-density lipoprotein cholesterol, triglycerides and apolipoprotein B, p < 6.5 × 10-24) profiles. The latter associations are replicated in our metabolome-wide association study. Proteomic perturbations associated with genetically predicted FGF21 effect were consistent with fibrosis reduction. CONCLUSION: This study highlights the pleiotropic effects of genetically proxied FGF21 and supports a re-purposing opportunity for the treatment and prevention of kidney disease specifically. Further work is required to triangulate these findings, towards possible clinical development of FGF21 towards the treatment and prevention of kidney disease.

Effect of Continuous Positive Airway Pressure on Glucose and Lipid Profiles in Patients With Obstructive Sleep Apnoea: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND AND AIM: Continuous Positive Airway Pressure (CPAP) is the most effective therapy for symptomatic obstructive sleep apnoea (OSA). However, uncertainty remains about the effectiveness of CPAP in improving OSA-related metabolic dysregulation. This meta-analysis of randomized controlled trials (RCTs) aimed to investigate whether CPAP, compared to other control treatments, could improve glucose or lipid metabolism in OSA patients. METHODS: Relevant articles were searched in three different databases (MEDLINE, EMBASE and Web of Science) from inception to 6th Feb 2022 through specific search terms and selection criteria. RESULTS: From a total of 5553 articles, 31 RCTs were included. CPAP modestly improved insulin sensitivity as determined by mean fasting plasma insulin and Homeostasis Model Assessment of Insulin Resistance reduction of 1.33mU/L and 0.287, respectively. In subgroup analyses pre-diabetic/type 2 diabetic patients as well as those with sleepy OSA showed a greater response to CPAP. Regarding lipid metabolism, CPAP was associated with a mean total cholesterol reduction of 0.064mmol/L. In subgroup analyses, the benefit was higher in patients that showed more severe OSA and oxygen desaturations at the baseline sleep study as well as in younger and obese subjects. Neither glycated haemoglobin nor triglycerides, HDL- and LDL-cholesterol were reduced by CPAP. CONCLUSION: CPAP treatment may improve insulin sensitivity and total cholesterol levels in OSA patients but with low effect size. Our results suggest that CPAP does not substantially improve metabolic derangements in an unselected OSA population, but the effect may be higher in specific subgroups of OSA patients.

Risk factors for pre-clinical atherosclerosis in adolescents with type 1 diabetes.

AIMS: To assess whether, besides "traditional" risk factors, overall oxidative stress, oxidized lipoproteins, and glycemic variability are associated with early macro-vascular damage in type 1 diabetes (T1D). METHODS: In 267 children/adolescents with T1D (130 girls, age 9.1-23.0 years) we evaluated: derivatives of reactive oxygen metabolites [d-ROMs], serum total antioxidant capacity [TAC] and oxidized LDL-cholesterol [oxLDL]; markers of early vascular damage (Lipoprotein-associated phospholipase A2 [Lp-PLA2], z-score of carotid intima-media thickness [z-cIMT] and carotid-femoral pulse wave velocity [z-PWV]); CGM metrics of four weeks preceding the visit, central systolic/diastolic blood pressures (cSBP/cDBP), and HbA1c, z-score of BP (z-SBP/z-DBP) and circulating lipids longitudinally collected since T1D onset.. Three general linear models were built with z-cIMT, z-PWV adjusted for current cDBP, and Lp-PLA2 as independent variables. RESULTS: The z-cIMT was associated with male gender (B = 0.491, η2 = 0.029, p = 0.005), cSBP (B = 0.023, η2 = 0.026, p = 0.008) and oxLDL (B = 0.022, η2 = 0.022, p = 0.014). The z-PWV was associated with diabetes duration (B = 0.054, η2 = 0.024, p = 0.016), daily insulin dose (B = 0.52, η2 = 0.018, p = 0.045), longitudinal z-SBP (B = 0.18, η2 = 0.018, p = 0.045) and dROMs (B = 0.003, η2 = 0.037, p = 0.004). Lp-PLA2 was associated with age (B = 0.221, η2 = 0.079, p = 3*10-6), oxLDL (B = 0.081, η2 = 0.050, p = 2*10-4), longitudinal LDL-cholesterol (B = 0.031, η2 = 0.043, p = 0.001) and male gender (B = -1.62, η2 = 0.10, p = 1.3*107). CONCLUSIONS: Oxidative stress, male gender, insulin dose, diabetes duration and longitudinal lipids and blood pressure, contributed to the variance of early vascular damage in young patients with T1D.

Calcium, Its Regulatory Hormones, and Their Causal Role on Blood Pressure: A Two-Sample Mendelian Randomization Study.

CONTEXT: Vitamin D (Vit-D), parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23) are the major calciotropic hormones involved in the regulation of blood calcium levels from the intestine, kidney, and bone through a tight endocrine feedback loop system. Altered levels of calcium itself or through the effect of its regulatory hormones could affect blood pressure (BP), but the exact mechanisms remain unclear. OBJECTIVE: To evaluate whether a causal relationship exists between serum calcium level and/or the regulatory hormones involved in its homeostasis with BP, we performed a two-sample Mendelian randomization (MR) study. METHODS: From 4 large genome-wide association studies (GWAS) we obtained independent (r2 < 0.001) single nucleotide polymorphisms (SNPs) associated with serum calcium (119 SNPs), Vit-D (78 SNPs), PTH (5 SNPs), and FGF23 (5 SNPs), to investigate through MR their association with systolic BP (SBP) and diastolic BP (DBP) in a Swedish urban-based study, the Malmö Diet and Cancer study (n = 29 298). Causality was evaluated by the inverse variance weighted method (IVW) and weighted median, while MR Egger and MR-PRESSO were used as sensitivity analyses. RESULTS: Genetically predicted serum calcium level was found to be associated with DBP (IVW: beta = 0.10, SE = 0.04, P = 0.007) and SBP (IVW: beta = 0.07, SE = 0.04, P = 0.04). Genetically predicted Vit-D and PTH showed no association with the traits, while FGF23 was inversely associated with SBP (IVW: beta = -0.11, SE = 0.04, P = 0.01), although this association lost statistical significance in sensitivity analysis. CONCLUSION: Our study shows a direct association between genetically predicted calcium level and DBP, and a weaker association with SBP. No such clear association was found for genetically predicted calciotropic hormone levels. It is of interest to detect which target genes involved in calcium homeostasis mediate the effect of calcium on BP, particularly for improving personalized intervention strategies.

Markers of subclinical vascular damage in young adults with type 1 diabetes mellitus: the role of central blood pressure.

INTRODUCTION: Type 1 diabetes mellitus (T1D) is a chronic disease leading to cardiovascular complications that can be diagnosed early as subclinical vascular damage. To prevent such damage, it is important to increase knowledge of the effects of the different cardiovascular risk factors in patients with T1D. The aim of our study was to assess possible associations between markers of subclinical arterial damage and traditional cardiovascular risk factors, with a special focus on peripheral blood pressure and central blood pressure (cBP), in a sample of young adults with T1D. PATIENTS AND METHODS: The study included 172 T1D patients (mean age 24.7 ±â€Š8.7 years, duration of T1D 13.5 ±â€Š9.6 years). Pulse wave velocity (PWV), pulse wave analysis and cBP were assessed by tonometry (SphygmoCor Xcel). Carotid intima-media thickness (cIMT) and carotid distensibility coefficient (cDC) were assessed by high-resolution echo-Doppler analysis and further examined with dedicated hardware. RESULTS: Seventeen patients (10.1%) were classified as hypertensive by office peripheral blood pressure, and 48 patients (27.9%) were classified as hypertensive by cBP. One hundred sixteen patients (68.8%) had cDC under the range of normality, one patient had a PWV (0.6%) above 10 m/s, and no patients had a cIMT above 0.9 mm. In multivariable analysis, central SBP, but not metabolic parameters, remained associated with all the markers of subclinical arterial damage [cIMT ( ß â€Š= 0.288 ±â€Š0.001; P  < 0.001), PWV ( ß â€Š= 0.374 ±â€Š0.007; P  < 0.001), cDC ( ß â€Š= -0.149 ±â€Š0.055; P  = 0.029)]. CONCLUSION: The independent association between cBP and markers of subclinical vascular damage underlines the importance of haemodynamic factors in the development of early signs of macrovascular disease in T1D patients. Further studies are warranted to better define the role of cBP to stratify cardiovascular risk, to individualize the need for follow-up and to tailor preventive strategies in T1D patients.

Multiancestry exome sequencing reveals INHBE mutations associated with favorable fat distribution and protection from diabetes.

Body fat distribution is a major, heritable risk factor for cardiometabolic disease, independent of overall adiposity. Using exome-sequencing in 618,375 individuals (including 160,058 non-Europeans) from the UK, Sweden and Mexico, we identify 16 genes associated with fat distribution at exome-wide significance. We show 6-fold larger effect for fat-distribution associated rare coding variants compared with fine-mapped common alleles, enrichment for genes expressed in adipose tissue and causal genes for partial lipodystrophies, and evidence of sex-dimorphism. We describe an association with favorable fat distribution (p = 1.8 × 10-09), favorable metabolic profile and protection from type 2 diabetes (~28% lower odds; p = 0.004) for heterozygous protein-truncating mutations in INHBE, which encodes a circulating growth factor of the activin family, highly and specifically expressed in hepatocytes. Our results suggest that inhibin ßE is a liver-expressed negative regulator of adipose storage whose blockade may be beneficial in fat distribution-associated metabolic disease.

Association of Thyroid Function with Blood Pressure and Cardiovascular Disease: A Mendelian Randomization.

Thyroid function has a widespread effect on the cardiometabolic system. However, the causal association between either subclinical hyper- or hypothyroidism and the thyroid hormones with blood pressure (BP) and cardiovascular diseases (CVD) is not clear. We aim to investigate this in a two-sample Mendelian randomization (MR) study. Single nucleotide polymorphisms (SNPs) associated with thyroid-stimulating hormone (TSH), free tetraiodothyronine (FT4), hyper- and hypothyroidism, and anti-thyroid peroxidase antibodies (TPOAb), from genome-wide association studies (GWAS), were selected as MR instrumental variables. SNPs-outcome (BP, CVD) associations were evaluated in a large-scale cohort, the Malmö Diet and Cancer Study (n = 29,298). Causal estimates were computed by inverse-variance weighted (IVW), weighted median, and MR-Egger approaches. Genetically increased levels of TSH were associated with decreased systolic BP and with a lower risk of atrial fibrillation. Hyperthyroidism and TPOAb were associated with a lower risk of atrial fibrillation. Our data support a causal association between genetically decreased levels of TSH and both atrial fibrillation and systolic BP. The lack of significance after Bonferroni correction and the sensitivity analyses suggesting pleiotropy, should prompt us to be cautious in their interpretation. Nevertheless, these findings offer mechanistic insight into the etiology of CVD. Further work into the genes involved in thyroid functions and their relation to cardiovascular outcomes may highlight pathways for targeted intervention.

Central Systolic Blood Pressure Is Associated With Early Vascular Damage in Children and Adolescents With Type 1 Diabetes.

Objective of the study: This study aimed to test the effect of multiple cardiovascular risk factors on subclinical indices of atherosclerosis in children and adolescents with type 1 diabetes (T1D). Methods: Carotid intima-media thickness (cIMT), carotid distensibility coefficient (cDC), and carotid-femoral pulse wave velocity (PWV) were measured in children and adolescents with T1D, in a follow-up at the outpatient clinics of Verona. Blood pressure (BP; both central and peripheral), metabolic and other cardiovascular risk factors were evaluated in multivariate linear regressions to assess the association with the measured indices of subclinical vascular damage. Results: One hundred and twenty-six children and adolescents were included. cIMT was above the 95th percentile for age and height in 60.8% of the population, whereas 26% of the sample had cDC impairment (less than the 5th percentile) and 4.8% had an elevated PWV. Independent determinants of cIMT according to the regression models were only gender type of glucose monitoring and central systolic BP (cSBP). PWV was associated with age, sex, heart rate, and cSBP; cDC with age and both cSBP and, alternatively, peripheral BP (pBP). Neither pBP nor any of the tested metabolic parameters, including glycated hemoglobin, was associated with PWV and cIMT. Conclusions: A high proportion of early vascular damage, especially an increased cIMT, is present in children and adolescents with T1D in whom cSBP seems to be a common determinant. In children and adolescents with T1DM, a special focus should be on hemodynamic risk factors beyond metabolic ones.

Causal Effect of Adiposity Measures on Blood Pressure Traits in 2 Urban Swedish Cohorts: A Mendelian Randomization Study.

Background Different adiposity traits may be causally related to hypertension in different ways. By using genetic variants as randomly allocated proxies for studying the effect of modifying adiposity traits, the Mendelian randomization approach can be used to investigate this. Methods and Results In this study, we used 4 different genetic risk scores (GRS; GRS-BMI565, GRS-WHR324, GRS-VAT208, GRS-BF81) including hundreds of single nucleotide polymorphisms associated with body mass index, waist-to-hip ratio, visceral adipose tissue, and body fat, respectively. These were applied as instrumental variables in Mendelian randomization analyses. Two Swedish urban-based cohort studies, the Malmö Diet and Cancer, and the Malmö Preventive 795Projects were used to obtain genetic association estimates with blood pressure (BP). In both the Malmö Preventive Projects and Malmö Diet and Cancer studies, except for that for body fat, all of the genetic risk scores were significantly associated with systolic BP and diastolic BP, but with different magnitudes. In particular, in both cohorts, each standard deviation increase in the genetic risk score made up by the 324 single nucleotide polymorphisms associated with waist-to-hip ratio was associated with doubling of the likelihood of hypertension prevalence at baseline. However, only the genetic risk score made up by the 565 SNPs associated with body mass index was significantly associated with hypertension incidence during 23.6±4.3 years of follow-up in the Malmö Preventive Project. Conclusions We support a causal link between genetically mediated adiposity, especially waist-to-hip ratio and body mass index, and BP traits including hypertension prevalence and, for the first time to our knowledge, hypertension incidence. The differences in magnitude between these associations might suggest different mechanisms by which different adiposity affects BP/hypertension and consequently may indicate that tailored interventions are needed to reduce cardiovascular risk.

Relationship Between Blood Pressure and Incident Cardiovascular Disease: Linear and Nonlinear Mendelian Randomization Analyses.

[Figure: see text].

Expression and functional characterization of the large-conductance calcium and voltage-activated potassium channel Kca 1.1 in megakaryocytes and platelets.

BACKGROUND: Ion channels are transmembrane proteins that play important roles in cell function regulation modulating ionic cell permeability. In megakaryocytes and platelets, regulated ion flows have been demonstrated to modulate platelet production and function. However, a relatively limited characterization of ion channel expression and function is available in the human megakaryocyte-platelet lineage. OBJECTIVE: We analyzed the expression and function of the large-conductance calcium and voltage-activated potassium channel Kca 1.1 (also known as Maxi-K, BK, slo1) in human megakaryocytes and platelets. METHODS: To investigate the functionality of Kca 1.1, we exploited different agonists (BMS-191011, NS1619, NS11021, epoxyeicosatrienoic acid isoforms) and inhibitors (iberiotoxin, penitrem A) of the channel. RESULTS: In megakaryocytes, Kca 1.1 agonists determined a decreased proplatelet formation and altered interaction with the extracellular matrix. Analysis of the actin cytoskeleton demonstrated a significant decrease in megakaryocyte spreading and adhesion to collagen. In platelets, the opening of the channel Kca 1.1 led to a reduced sensitivity to agonists with blunted aggregation in response to ADP, with an inhibitory capacity additive to that of aspirin. The Kca 1.1 agonists, but not the inhibitors, determined a reduction of platelet adhesion and aggregation onto immobilized collagen underflow to an extent similar to that of aspirin and ticagrelor. The opening of the Kca 1.1 resulted in cell hyperpolarization impairing free intracellular calcium in ADP-stimulated platelets and megakaryocytes. CONCLUSIONS: The present study reveals new mechanisms in platelet formation and activation, suggesting that targeting Kca 1.1 channels might be of potential pharmacological interest in hemostasis and thrombosis.

Influence of genetic variants in FADS2 and ELOVL2 genes on BMI and PUFAs homeostasis in children and adolescents with obesity.

BACKGROUND: Several studies identified genetic variants in FADS and ELOVL2 genes associated with obesity-related conditions, such as alterations in blood lipid parameters and insulin homeostasis. The aim of this cross-sectional study was to determine whether FADS and ELOVL2 genetic variants were associated with obesity and adiposity, besides dyslipidaemia and insulin resistance, in a large sample of obese children and adolescents. MATERIALS AND METHODS: One thousand six hundred and forty-nine obese children underwent physical examination, anthropometry, fasting blood tests measuring plasma glucose, lipid and liver profile. Two genetic variants were genotyped: rs2236212 in ELOVL2 gene and rs1535 in FADS2, for the gene cluster FADS. In a subgroup of obese children (n = 105), erythrocyte fatty acid composition was measured. Generalized linear models were used to assess association between genotypes and variables. RESULTS: A positive association between zBMI and the minor allele of rs2236212 (p = 0.028), the major allele of rs1535 (p = 0.046) and the genetic score (p = 0.008), created by summing up both risk alleles, were found. The estimation of enzymatic activity revealed that minor alleles were associated significantly with a reduction of the enzymatic activity of elongase and desaturase (p = 0.048 and p = 0.0001, respectively). DISCUSSION AND CONCLUSIONS: Common variants in the FADS2 and ELOVL2 genes were associated with BMI in a large population of obese Italian children. These SNPs were associated with alterations in LC-PUFAs homeostasis, not accompanied by modifications of plasma lipids or HOMA-IR. These findings provide additional support to the genetics accounting for BMI interindividual variability and the molecular basis of obesity.

Clinical Evaluation of the Polygenetic Background of Blood Pressure in the Population-Based Setting.

The clinical value of the polygenetic component of blood pressure (BP) is commonly questioned. We evaluated a genetic risk score for BP (BP-GRS858), based on the most recently published genome-wide association studies variants that were significantly associated with either systolic BP or diastolic BP, for prediction of hypertension and cardiovascular end points. The genotyping was performed in 2 urban-based prospective cohorts: the Malmö Diet and Cancer (n=29 295) and the Malmö Preventive Project (n=9367) and a weighted BP-GRS858 based on 858 SNPs was calculated. At baseline, we found a difference of 9.0 mm Hg (systolic BP) and 4.8 mm Hg (diastolic BP) between the top and the bottom quartile of BP-GRS858. In Malmö Preventive Project, the top versus bottom quartile of BP-GRS858 was associated with a doubled risk of incident hypertension (odds ratio, 2.05 [95% CI, 1.75-2.39], P=1.4×10-21), a risk higher than that of body mass index, as evaluated in quartiles. In Malmö Diet and Cancer, significant association was found between the age and sex-adjusted BP-GRS858 and the incidence of total cardiovascular events, stroke, coronary artery disease, heart failure, atrial fibrillation, and total mortality. Most of these associations remained significant after adjusting for traditional risk factors, including hypertension. BP-GRS858 could contribute predictive information regarding future hypertension, with an effect size comparable to other well-known risk factors such as obesity, and predicts cardiovascular events. Given that the exposure to high polygenetic risk starts at birth, we suggest that the BP-GRS858 might be useful to identify children or adolescents who would benefit from early hypertension screening and treatment.

Circulating Bile Acids Profiles in Obese Children and Adolescents: A Possible Role of Sex, Puberty and Liver Steatosis.

BACKGROUND: Childhood obesity is becoming a major health issue and contributes to increasing the risk of cardiovascular disease in adulthood. Since dysregulated metabolism of bile acids (BAs) plays a role in progression of obesity-related disorders, including steatosis and hypertension, this study aimed to investigate BAs profiles in obese children with and without steatosis and hypertension, as well as exploring the interplay between BAs profile and vascular function. METHODS: BAs concentrations were quantified with liquid chromatography-tandem mass spectrometry in 69 overweight/obese children and adolescents (mean age, 11.6 ± 2.5 years; 30 females). Liver steatosis was defined with abdomen ultrasonography, whilst hypertension was defined according to the current European guidelines. Vascular function was assessed with ultrasound technique, by measuring carotid intima media thickness (cIMT) and common carotid artery distensibility (cDC). RESULTS: Total and individual glycine-conjugated BAs concentrations were found to be significantly higher in males compared to females, as well as in pre-pubertal compared to pubertal stage (p < 0.05 for both). No difference in BAs concentration was observed between hypertensive and normotensive subjects. Total BAs and glycine conjugated BAs were significantly higher in participants with steatosis compared to those without (p = 0.004 for both). The values of total glycine-conjugate acids were positively correlated with cDC and this association remained significant in linear regression after adjusting for sex, age, pubertal stage, body mass index and aspartate aminotransferase. CONCLUSION: The results suggest a possible role of BAs in the pathogenesis of liver and/or vascular damage in children and adolescent. Further studies are hence needed to validate these preliminary findings.

Fatty Acid Profile and Desaturase Activities in 7-10-Year-Old Children Attending Primary School in Verona South District: Association between Palmitoleic Acid, SCD-16, Indices of Adiposity, and Blood Pressure.

In previous studies, dietary and circulating fatty acids (FA) and desaturases activity (delta-5 desaturase [D5D], delta-6 desaturase [D6D], and stearoyl-CoA desaturase [SCD-16]) involved in their metabolism were associated with metabolic and cardiovascular disorders. The aim of the study was to assess the association between different FAs and desaturases activity (estimated as product:precursor ratios) with individual cardiovascular risk factors (in particular, anthropometric measurements and blood pressure [BP]) in children. The FA profile was determined on a whole-blood drop in 243 children (age: 8.6 ± 0.72 years) participating in a school-based cross-sectional study. Docosahexaenoic acid (DHA) inversely correlated with indices of adiposity, glucose, and triglycerides. Palmitoleic acid and SCD-16 were directly associated with markers of adiposity and BP, even after adjustment for main confounders. D6D correlated directly with the waist/height ratio. Children with excess weight (>85th percentile; that is overweight plus obese ones) showed higher palmitic acid, palmitoleic acid, and higher SCD-16 activity as compared to normal-weight children. Most of the associations were confirmed in the excess-weight group. Omega-3 FAs, particularly DHA, but not omega-6 FA, showed a potentially beneficial association with metabolic parameters, whereas palmitoleic acid and SCD-16 showed a potentially harmful association with indices of adiposity and BP, especially in obese children.