Statin therapy in multimorbid older patients with polypharmacy- a cross-sectional analysis of the Swiss OPERAM trial population.

Background: Statin therapy in multimorbid older individuals with polypharmacy is controversial, particularly in primary prevention of cardiovascular disease. Thereby, physicians must weigh potential benefits against potential side effects, drug-drug interactions, and limited life expectancy. Aim: To assess the prevalence and determinants of potentially inappropriate statin therapy in multimorbid older patients. Methods: We conducted a cross-sectional analysis of patients aged ≥70 years with multimorbidity and polypharmacy in the Swiss study center of OPERAM, a cluster-randomized trial on pharmacotherapy optimization to reduce drug-related hospital admissions. We assessed potential underuse (no statin but formal indication) and potential overuse (statin but no formal indication, including predicted >60% one-year mortality based on the Walter Score) based on current guidelines for patients in secondary and primary cardiovascular prevention. We assessed the association of potential statin overuse and underuse with six patient characteristics (age, gender, number of diagnoses, number of medications, mental impairment, being housebound) in LASSO-selection analyses. Results: Of 715 multimorbid older adults (79.7 ± 6.5 years, 39.9% women), 337 (47%) were on statin. Statin therapy was appropriate in 474 (66.3%), underused in 130 (18.2%), and overused in 111 (15.5%) patients. In participants in secondary cardiovascular prevention (n = 437), being female (odds ratio [OR] 2.65, 95% confidence interval [CI] 1.67-4.22) was significantly associated with potential underuse while being housebound (OR 3.53, 95%CI 1.32-9.46) and taking ≥10 medications (OR 1.95,95%CI 1.05-3.67) were associated with potential overuse. In participants in primary cardiovascular prevention (n = 278), 28.1% were potentially under- (9%) or overusing (19%) a statin, with no identified risk factor. Conclusion: A third of hospitalized multimorbid older patients with polypharmacy potentially (either) overused or underused statin therapy. Among patients in secondary cardiovascular prevention, women were at risk for potential statin underuse. Housebound patients and those taking ≥10 medications were at risk for potential overuse of a statin. Physicians should carefully evaluate the indication for statin prescription in multimorbid older patients with polypharmacy.

Association of sex and cardiovascular risk factors with atherosclerosis distribution pattern in lower extremity peripheral artery disease.

Objective: Atherosclerosis expression varies across not only coronary, cerebrovascular, and peripheral arteries but also within the peripheral vascular tree. The underlying pathomechanisms of distinct atherosclerosis phenotypes in lower extremity peripheral artery disease (PAD) is poorly understood. We investigated the association of cardiovascular risk factors (CVRFs) and atherosclerosis distribution in a targeted approach analyzing symptomatic patients with isolated anatomic phenotypes of PAD. Methods: In a cross-sectional analysis of consecutive patients undergoing first-time endovascular recanalization for symptomatic PAD, data of patients with isolated anatomic phenotypes of either proximal (iliac) or distal (infrageniculate) atherosclerosis segregation were extracted. We performed a multivariable logistic regression model with backward elimination to investigate the association of proximal and distal PAD with CVRFs. Results: Of the 637 patients (29% females) with endovascular recanalization, 351 (55%) had proximal and 286 (45%) had distal atherosclerosis. Female sex [odds ratio (OR) 0.33, 95% confidence interval (CI) 0.20-0.54, p = 0.01], active smoking (OR 0.16, 95% CI 0.09-0.28, p < 0.001), and former smoking (OR 0.33, 95% CI 0.20-0.57, p < 0.001) were associated with proximal disease. Diabetes mellitus (DM) (OR 3.25, 95% CI 1.93-5.46, p < 0.001), chronic kidney disease (CKD) (OR 1.18, 95% CI 1.08-1.28, p < 0.001), and older age (OR 1.31, 95% CI 1.06-1.61, p = 0.01) were associated with distal disease. Conclusion: Female sex, particularly in the context of smoking, is associated with clinically relevant, proximal atherosclerosis expression. Our additional findings that distal atherosclerosis expression is associated with DM, CKD, and older age suggest that PAD has at least two distinct atherosclerotic phenotypes with sex-specific and individual susceptibility to atherogenic risk factors.

Overtreatment and associated risk factors among multimorbid older patients with diabetes.

BACKGROUND: In multimorbid older patients with type 2 diabetes mellitus (T2DM), the intensity of glucose-lowering medication (GLM) should be focused on attaining a suitable level of glycated hemoglobin (HbA1c ) while avoiding side effects. We aimed at identifying patients with overtreatment of T2DM as well as associated risk factors. METHODS: In a secondary analysis of a multicenter study of multimorbid older patients, we evaluated HbA1c levels among patients with T2DM. Patients were aged ≥70 years, with multimorbidity (≥3 chronic diagnoses) and polypharmacy (≥5 chronic medications), enrolled in four university medical centers across Europe (Belgium, Ireland, Netherlands, and Switzerland). We defined overtreatment as HbA1c < 7.5% with ≥1 GLM other than metformin, as suggested by Choosing Wisely and used prevalence ratios (PRs) to evaluate risk factors of overtreatment in age- and sex-adjusted analyses. RESULTS: Among the 564 patients with T2DM (median age 78 years, 39% women), mean ± standard deviation HbA1c was 7.2 ± 1.2%. Metformin (prevalence 51%) was the most frequently prescribed GLM and 199 (35%) patients were overtreated. The presence of severe renal impairment (PR 1.36, 1.21-1.53) and outpatient physician (other than general practitioner [GP], i.e. specialist) or emergency department visits (PR 1.22, 1.03-1.46 for 1-2 visits, and PR 1.35, 1.19-1.54 for ≥3 visits versus no visits) were associated with overtreatment. These factors remained associated with overtreatment in multivariable analyses. CONCLUSIONS: In this multicountry study of multimorbid older patients with T2DM, more than one third were overtreated, highlighting the high prevalence of this problem. Careful balancing of benefits and risks in the choice of GLM may improve patient care, especially in the context of comorbidities such as severe renal impairment, and frequent non-GP healthcare contacts.

Association between diabetes overtreatment in older multimorbid patients and clinical outcomes: an ancillary European multicentre study.

BACKGROUND: Diabetes overtreatment is a frequent and severe issue in multimorbid older patients with type 2 diabetes (T2D). OBJECTIVE: This study aimed at assessing the association between diabetes overtreatment and 1-year functional decline, hospitalisation and mortality in older inpatients with multimorbidity and polypharmacy. METHODS: Ancillary study of the European multicentre OPERAM project on multimorbid patients aged ≥70 years with T2D and glucose-lowering treatment (GLT). Diabetes overtreatment was defined according to the 2019 Endocrine Society guideline using HbA1c target range individualised according to the patient's overall health status and the use of GLT with a high risk of hypoglycaemia. Multivariable regressions were used to assess the association between diabetes overtreatment and the three outcomes. RESULTS: Among the 490 patients with T2D on GLT (median age: 78 years; 38% female), 168 (34.3%) had diabetes overtreatment. In patients with diabetes overtreatment as compared with those not overtreated, there was no difference in functional decline (29.3% vs 38.0%, P = 0.088) nor hospitalisation rates (107.3 vs 125.8/100 p-y, P = 0.115) but there was a higher mortality rate (32.8 vs 21.4/100 p-y, P = 0.033). In multivariable analyses, diabetes overtreatment was not associated with functional decline nor hospitalisation (hazard ratio, HR [95%CI]: 0.80 [0.63; 1.02]) but was associated with a higher mortality rate (HR [95%CI]: 1.64 [1.06; 2.52]). CONCLUSIONS: Diabetes overtreatment was associated with a higher mortality rate but not with hospitalisation or functional decline. Interventional studies should be undertaken to test the effect of de-intensifying GLT on clinical outcomes in overtreated patients.

[Should dyslipidemia be treated in the elderly and very old people?] / Faut-il traiter les dyslipidémies chez les personnes âgées et très âgées ?

The beneficial effect of statins on the risk of recurrence of cardiovascular disease (secondary prevention) is well demonstrated. In primary prevention (no symptomatic cardiovascular disease), the benefit of statins after the age of 70 years is less clear and elderly patients with comorbidities have often been excluded from large, randomized trials. Some ongoing clinical trials will provide more information on the potential benefits and risks of starting or stopping statins in older adults. In clinical practice, the decision to treat with statins needs to take into account age, comorbidities, life expectancy, functional and cognitive status and patient preferences (shared decision), but statin discontinuation is only recommended in the context of a clinical trial, as reviewed in this article.

L'effet bénéfique des statines sur le risque de récidive de maladie cardiovasculaire (prévention secondaire) est bien démontré. En prévention primaire (pas de maladie cardiovasculaire symptomatique), le bénéfice des statines après 70 ans est moins clair et les patients âgés avec des comorbidités ont souvent été exclus des grandes études randomisées. Des essais cliniques sont en cours et apporteront plus d'informations sur les potentiels effets bénéfiques et risques de débuter ou d'arrêter les statines chez les personnes âgées. Dans la pratique, en sus de l'âge, la décision de traiter par statine nécessite de prendre en compte les comorbidités, l'espérance de vie, l'état fonctionnel et cognitif et les souhaits du patient (décision partagée), mais un arrêt n'est recommandé que dans le cadre d'un essai clinique, comme revu dans cet article.

No Effect of Levothyroxine on Hemoglobin in Older Adults With Subclinical Hypothyroidism: Pooled Results From 2 Randomized Controlled Trials.

CONTEXT: Subclinical thyroid dysfunction and anemia are common disorders, and both have increasing prevalence with advancing age. OBJECTIVE: The aim of this study was to assess whether levothyroxine treatment leads to a rise in hemoglobin levels in older persons with subclinical hypothyroidism. METHODS: This preplanned combined analysis of 2 randomized controlled trials included community-dwelling persons aged 65 years and older with subclinical hypothyroidism who were randomly assigned to levothyroxine or placebo treatment. The levothyroxine dose was periodically titrated aiming at thyroid stimulating hormone (TSH) level within the reference range, with mock titrations in the placebo group. The main outcome measure was the change in hemoglobin level after 12 months. RESULTS: Analyses included 669 participants (placebo n = 337, levothyroxine n = 332) with a median age of 75 years (range, 65-97) and mean baseline hemoglobin of 13.8 ±â€…1.3 g/dL. Although levothyroxine treatment resulted in a reduction in TSH from baseline after 12 months of follow-up compared with placebo, the change in hemoglobin level was not different between the levothyroxine and the placebo groups (-0.03 g/dL [95% CI, -0.16 to 0.11]). Similar results were found in stratified analyses including sex, age, or TSH levels. No difference in change of hemoglobin levels after 12 months was identified in 69 participants with anemia at baseline (-0.33 g/dL [95% CI, -0.87 to 0.21]). CONCLUSION: In persons aged 65 years and older with subclinical hypothyroidism, treatment with levothyroxine does not lead to a rise in hemoglobin levels, regardless of the presence of anemia.

Cross-sectional study on the prevalence of influenza and pneumococcal vaccination and its association with health conditions and risk factors among hospitalized multimorbid older patients.

BACKGROUND: Older adults with chronic conditions are at high risk of complications from influenza and pneumococcal infections. Evidence about factors associated with influenza and pneumococcal vaccination among older multimorbid persons in Europe is limited. The aim of this study was to investigate the prevalence and determinants of these vaccinations in this population. METHODS: Multimorbid patients aged ≥70 years with polypharmacy were enrolled in 4 European centers in Switzerland, Belgium, the Netherlands, and Ireland. Data on vaccinations, demographics, health care contacts, and comorbidities were obtained from self-report, general practitioners and medical records. The association of comorbidities or medical contacts with vaccination status was assessed using multivariable adjusted log-binomial regression models. RESULTS: Among 1956 participants with available influenza vaccination data (median age 79 years, 45% women), 1314 (67%) received an influenza vaccination within the last year. Of 1400 patients with available pneumococcal vaccination data (median age 79 years, 46% women), prevalence of pneumococcal vaccination was 21% (n = 291). The prevalence of vaccination remained low in high-risk populations with chronic respiratory disease (34%) or diabetes (24%), but increased with an increasing number of outpatient medical contacts. Chronic respiratory disease was independently associated with the receipt of both influenza and pneumococcal vaccinations (prevalence ratio [PR] 1.09, 95% confidence interval [CI] 1.03-1.16; and PR 2.03, 95%CI 1.22-3.40, respectively), as was diabetes (PR 1.06, 95%CI 1.03-1.08; PR 1.24, 95%CI 1.16-1.34, respectively). An independent association was found between number of general practitioner visits and higher prevalence of pneumococcal vaccination (p for linear trend <0.001). CONCLUSION: Uptake of influenza and particularly of pneumococcal vaccination in this population of European multimorbid older inpatients remains insufficient and is determined by comorbidities and number and type of health care contacts, especially outpatient medical visits. Hospitalization may be an opportunity to promote vaccination, particularly targeting patients with few outpatient physician contacts.

Association of Diabetes With Atrial Fibrillation Phenotype and Cardiac and Neurological Comorbidities: Insights From the Swiss-AF Study.

Background Diabetes is a major risk factor for atrial fibrillation (AF). However, it remains unclear whether individual AF phenotype and related comorbidities differ between patients who have AF with and without diabetes. This study investigated the association of diabetes with AF phenotype and cardiac and neurological comorbidities in patients with documented AF. Methods and Results Participants in the multicenter Swiss-AF (Swiss Atrial Fibrillation) study with data on diabetes and AF phenotype were eligible. Primary outcomes were parameters of AF phenotype, including AF type, AF symptoms, and quality of life (assessed by the European Quality of Life-5 Dimensions Questionnaire [EQ-5D]). Secondary outcomes were cardiac (ie, history of hypertension, myocardial infarction, and heart failure) and neurological (ie, history of stroke and cognitive impairment) comorbidities. The cross-sectional association of diabetes with these outcomes was assessed using logistic and linear regression, adjusted for age, sex, and cardiovascular risk factors. We included 2411 patients with AF (27.4% women; median age, 73.6 years). Diabetes was not associated with nonparoxysmal AF (odds ratio [OR], 1.01; 95% CI, 0.81-1.27). Patients with diabetes less often perceived AF symptoms (OR, 0.74; 95% CI, 0.59-0.92) but had worse quality of life (ß=-4.54; 95% CI, -6.40 to -2.68) than those without diabetes. Patients with diabetes were more likely to have cardiac (hypertension [OR, 3.04; 95% CI, 2.19-4.22], myocardial infarction [OR, 1.55; 95% CI, 1.18-2.03], heart failure [OR, 1.99; 95% CI, 1.57-2.51]) and neurological (stroke [OR, 1.39, 95% CI, 1.03-1.87], cognitive impairment [OR, 1.75, 95% CI, 1.39-2.21]) comorbidities. Conclusions Patients who have AF with diabetes less often perceive AF symptoms but have worse quality of life and more cardiac and neurological comorbidities than those without diabetes. This raises the question of whether patients with diabetes should be systematically screened for silent AF. Registration URL: https://www.clinicaltrials.gov; Unique Identifier: NCT02105844.

Optimizing Therapy to Prevent Avoidable Hospital Admissions in Multimorbid Older Adults (OPERAM): cluster randomised controlled trial.

OBJECTIVE: To examine the effect of optimising drug treatment on drug related hospital admissions in older adults with multimorbidity and polypharmacy admitted to hospital. DESIGN: Cluster randomised controlled trial. SETTING: 110 clusters of inpatient wards within university based hospitals in four European countries (Switzerland, Netherlands, Belgium, and Republic of Ireland) defined by attending hospital doctors. PARTICIPANTS: 2008 older adults (≥70 years) with multimorbidity (≥3 chronic conditions) and polypharmacy (≥5 drugs used long term). INTERVENTION: Clinical staff clusters were randomised to usual care or a structured pharmacotherapy optimisation intervention performed at the individual level jointly by a doctor and a pharmacist, with the support of a clinical decision software system deploying the screening tool of older person's prescriptions and screening tool to alert to the right treatment (STOPP/START) criteria to identify potentially inappropriate prescribing. MAIN OUTCOME MEASURE: Primary outcome was first drug related hospital admission within 12 months. RESULTS: 2008 older adults (median nine drugs) were randomised and enrolled in 54 intervention clusters (963 participants) and 56 control clusters (1045 participants) receiving usual care. In the intervention arm, 86.1% of participants (n=789) had inappropriate prescribing, with a mean of 2.75 (SD 2.24) STOPP/START recommendations for each participant. 62.2% (n=491) had ≥1 recommendation successfully implemented at two months, predominantly discontinuation of potentially inappropriate drugs. In the intervention group, 211 participants (21.9%) experienced a first drug related hospital admission compared with 234 (22.4%) in the control group. In the intention-to-treat analysis censored for death as competing event (n=375, 18.7%), the hazard ratio for first drug related hospital admission was 0.95 (95% confidence interval 0.77 to 1.17). In the per protocol analysis, the hazard ratio for a drug related hospital admission was 0.91 (0.69 to 1.19). The hazard ratio for first fall was 0.96 (0.79 to 1.15; 237 v 263 first falls) and for death was 0.90 (0.71 to 1.13; 172 v 203 deaths). CONCLUSIONS: Inappropriate prescribing was common in older adults with multimorbidity and polypharmacy admitted to hospital and was reduced through an intervention to optimise pharmacotherapy, but without effect on drug related hospital admissions. Additional efforts are needed to identify pharmacotherapy optimisation interventions that reduce inappropriate prescribing and improve patient outcomes. TRIAL REGISTRATION: ClinicalTrials.gov NCT02986425.

The Omega-3 Fatty Acid Eicosapentaenoic Acid (EPA) Correlates Inversely with Ischemic Brain Infarcts in Patients with Atrial Fibrillation.

The omega-3 fatty acid (n-3 FA) eicosapentaenoic acid (EPA) reduces stroke in patients with atherosclerotic cardiovascular disease. Whether EPA affects stroke or cerebral small vessel dis-ease in patients with atrial fibrillation (AF) remains uncertain. EPA, docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and alpha-linolenic acid (ALA) were determined by gas chromatography in 1657 AF patients from the Swiss Atrial Fibrillation study. All patients underwent brain MRI to detect ischemic brain infarcts, classified as large noncortical or cortical infarcts (LNCCIs); markers of small vessel disease, classified as small noncortical infarcts (SNCIs), number of microbleeds, and white matter lesion (WML) volumes. Individual and total n-3 FAs (EPA + DHA + DPA + ALA) were correlated with LNCCIs and SNCIs using logistic regression, with numbers of microbleeds using a hurdle model, and WML volumes using linear regression. LNCCIs were detected in 372 patients (22.5%). EPA correlated inversely with the prevalence of LNCCIs (odds ratio [OR] 0.51 per increase of 1 percentage point EPA, 95% confidence interval [CI] 0.29-0.90). DPA correlated with a higher LNCCI prevalence (OR 2.48, 95%CI 1.49-4.13). No associations with LNCCIs were found for DHA, ALA, and total n-3 FAs. Neither individual nor total n-3 FAs correlated with markers of small vessel disease. In conclusion, EPA correlates inversely with the prevalence of ischemic brain infarcts, but not with markers of small vessel disease in patients with AF.

Alcohol consumption and risk of cardiovascular outcomes and bleeding in patients with established atrial fibrillation.

BACKGROUND: Little is known about the association between alcohol consumption and risk of cardiovascular events in patients with established atrial fibrillation (AF). The main aim of the current study was to investigate the associations of regular alcohol intake with incident stroke or systemic embolism in patients with established AF. METHODS: To assess the association between alcohol consumption and cardiovascular events in patients with established AF, we combined data from 2 comparable prospective cohort studies that followed 3852 patients with AF for a median of 3.0 years. Patients were grouped into 4 categories of daily alcohol intake (none, > 0 to < 1, 1 to < 2 and ≥ 2 drinks/d). The primary outcome was a composite of stroke and systemic embolism. Secondary outcomes were all-cause mortality, myocardial infarction, hospital admission for acute heart failure, and a composite of major and clinically relevant nonmajor bleeding. Associations were assessed using time-updated, multivariable-adjusted Cox proportional hazards models. RESULTS: Mean age (± standard deviation) was 71 ± 10 years (28% were women and 84% were on oral anticoagulants). We observed 136 confirmed strokes or systemic emboli. Compared with nondrinkers, adjusted hazard ratios for the primary outcome event were 0.87, 95% confidence interval (CI) 0.55-1.37 for > 0 to < 1 drinks/d; 0.70, 95% CI 0.39-1.25 for 1 to < 2 drinks/d; and 0.96, 95% CI 0.56-1.67 for ≥ 2 drinks/d (p for linear [quadratic] trend 0.71 [0.22]). There was no significant association between alcohol consumption and bleeding, but there was a nonlinear association with heart failure (p for quadratic trend 0.01) and myocardial infarction (p for quadratic trend 0.007). INTERPRETATION: In patients with AF, we did not find a significant association between low to moderate alcohol intake and risk of stroke or other cardiovascular events. Our findings do not support special recommendations for patients with established AF with regard to alcohol consumption. TRIAL REGISTRATION: ClinicalTrials.gov, no. NCT02105844.

The Admit-AF risk score: A clinical risk score for predicting hospital admissions in patients with atrial fibrillation.

AIMS: To develop and externally validate a risk score for all-cause hospital admissions in patients with atrial fibrillation. METHODS AND RESULTS: We used a prospective cohort of 2387 patients with established atrial fibrillation as derivation cohort. Independent risk factors were selected from a broad range of variables using the least absolute shrinkage and selection operator method fit to a Cox model. The risk score was validated in a separate prospective cohort of 1300 atrial fibrillation patients. The incidence of all-cause hospital admission was 19.1 per 100 person-years in the derivation cohort and it was 26.1 per 100 person-years in the validation cohort. The most important predictors for admission were age (75-79 years: adjusted hazard ratio (aHR), 1.34; 95% confidence interval (CI), 1.01-1.78; 80-84 years: aHR, 1.50; 95% CI, 1.11-2.03; ≥85 years: aHR, 1.88; 95% CI, 1.36-2.62), prior pulmonary vein isolation (aHR, 0.72; 95% CI, 0.58-0.88), hypertension (aHR, 1.16; 95% CI, 0.99-1.36), diabetes (aHR, 1.38; 95% CI, 1.17-1.62), coronary heart disease (aHR, 1.17; 95% CI, 1.02-1.36), prior stroke/transient ischaemic attack (aHR, 1.26; 95% CI, 1.18-1.47), heart failure (aHR, 1.19; 95% CI, 1.03-1.39), peripheral artery disease (aHR, 1.35; 95% CI, 1.08-1.67), cancer (aHR, 1.33; 95% CI, 1.12-1.57), renal failure (aHR, 1.17; 95% CI, 0.99-1.37) and previous falls (aHR, 1.40; 95% CI, 1.13-1.74). A risk score with these variables was well calibrated, and achieved a C-index of 0.64 in the derivation and 0.59 in the validation cohort. CONCLUSIONS: Multiple risk factors were associated with hospital admissions in atrial fibrillation patients. This prediction tool selects high-risk patients who may benefit from preventive interventions.

No Protective Effect of Constitutive Activation of AMPK in Endothelial Cells on Vascular Function in Aged Obese Mice but Augmented α1-Adrenergic Contractions in Renal Arteries Reversible by Weight Loss.

BACKGROUND: Aging, obesity, and diabetes favor vascular dysfunction. Endothelial activation of adenosine monophosphate-activated protein kinase (AMPK) has protective effects in diabetes. METHODS: Mice with constitutive endothelial activation of AMPK (CA-AMPK) were given a high fat diet to induce obesity or kept on standard chow as lean controls for up to 2 years. A subset of obese animals was changed to standard chow after 30 weeks of high fat feeding. En-dothelium-dependent and endothelium-independent responses were examined by isometric tension recording. RESULTS AND CONCLUSION: Endothelium-dependent nitric oxide (NO)- and apamin plus charybdotoxin-sensitive relaxations were preserved and similar between aortic or renal arterial preparations of lean and obese CA-AMPK mice and their wild-type littermates. Despite comparable release of vasoconstrictor prostanoids, cyclooxygenase-dependent contractions were enhanced during NO synthase inhibition in carotid arterial rings of obese CA-AMPK mice. Contractions to the α1-adrenoceptor agonist phenylephrine were augmented in renal arteries of obese animals, a genotype-independent phenomenon reversible by weight loss. These data indicate a higher α1-adrenergic reactivity in renal arteries of aged mice with obesity. The current results highlight the potential of weight loss to alleviate vascular dysfunction. However, endothelial activation of the AMPK pathway in obesity may not be sufficient to prevent vascular dysfunction without lifestyle changes.

Endothelial overexpression of endothelin-1 modulates aortic, carotid, iliac and renal arterial responses in obese mice.

Endothelin-1 (ET-1) is essential for mammalian development and life, but it has also been implicated in increased cardiovascular risk under pathophysiological conditions. The aim of this study was to determine the impact of endothelial overexpression of the prepro-endothelin-1 gene on endothelium-dependent and endothelium-independent responses in the conduit and renal arteries of lean and obese mice. Obesity was induced by high-fat-diet (HFD) consumption in mice with Tie-1 promoter-driven, endothelium-specific overexpression of the prepro-endothelin-1 gene (TEThet) and in wild-type (WT) littermates on a C57BL/6N background. Isometric tension was measured in rings (with endothelium) of the aorta (A), carotid (CA) and iliac (IA) arteries as well as the main (MRA) and segmental renal (SRA) arteries; all experiments were conducted in the absence or presence of L-NAME and/or the COX inhibitor meclofenamate. The release of prostacyclin and thromboxane A2 was measured by ELISA. In the MRA, TEThet per se increased contractions to endothelin-1, but the response was decreased in SRA in response to serotonin; there were also improved relaxations to acetylcholine but not insulin in the SRA in the presence of L-NAME. HFD per se augmented the contractions to endothelin-1 (MRA) and to the thromboxane prostanoid (TP) receptor agonist U46619 (CA, MRA) as well as facilitated relaxations to isoproterenol (A). The combination of HFD and TEThet overexpression increased the contractions of MRA and SRA to vasoconstrictors but not in the presence of meclofenamate; this combination also augmented further relaxations to isoproterenol in the A. Contractions to endothelin-1 in the IA were prevented by endothelin-A receptor antagonist BQ-123 but only attenuated in obese mice by BQ-788. The COX-1 inhibitor FR122047 abolished the contractions of CA to acetylcholine. The release of prostacyclin during the latter condition was augmented in samples from obese TEThet mice and abolished by FR122047. These findings suggest that endothelial TEThet overexpression in lean animals has minimal effects on vascular responsiveness. However, if comorbid with obesity, endothelin-1-modulated, prostanoid-mediated renal arterial dysfunction becomes apparent.

Obesity and heterozygous endothelial overexpression of prepro-endothelin-1 modulate responsiveness of mouse main and segmental renal arteries to vasoconstrictor agents.

AIMS: Levels of the endothelium-derived peptide endothelin-1 (ET-1) are elevated in obese humans, and ET-1 mediated vascular tone is increased. Renal arterial smooth muscle is highly responsive to ET-1. Whether or not endothelium-derived ET-1 affects contractions of the renal artery under normal conditions or in obesity is unknown. The present study was designed to investigate whether or not overexpression of endogenous ET-1 in the endothelium affects the responsiveness of the main and segmental renal arteries differently in obesity. MAIN METHODS: Mice with tie-1 promoter-driven endothelium-restricted heterozygous overexpression of preproendothelin-1 were used (TET(het)). Obesity was induced in TET(het) mice and wild-type (WT) littermates by feeding a high fat diet for 30 weeks; lean controls were kept on standard chow. The renal arteries were studied in wire myographs testing contractions (in the presence of l-NAME) to ET-1, serotonin, and U46619. KEY FINDINGS: Contractions to ET-1 were comparable between groups in main renal arteries, but augmented in segmental preparations from obese mice. Serotonin-induced responses were enhanced in obese TET(het) mice renal arteries compared to lean controls. Concentration-contraction curves to U46619 were shifted significantly to the left in main renal arteries of obese animals, and the maximal response was significantly increased between lean and obese TET(het) mice. SIGNIFICANCE: These results indicate an augmented responsiveness of main renal arteries in obesity particularly to TP receptor activation. When combined with endothelial ET-1 overexpression this effect is even more pronounced, which may help to gain further insights into the mechanisms of hypertension in obesity.

Acidosis prevents and alkalosis augments endothelium-dependent contractions in mouse arteries.

Changes in pH modulate the responsiveness of vascular smooth muscle cells to vasoconstrictor stimuli, but their effect on endothelium-dependent responses is unknown. Therefore, the influence of moderate changes in pH on responses to endothelium-dependent and -independent agonists was determined in aortae and carotid arteries of 15- to 26-week-old male C57BL/6N mice. Isolated rings were suspended in Halpern-Mulvany myographs for isometric tension recording. The preparations were exposed to either acidic (pH 7), control (pH 7.4) or alkaline (pH 7.8) modified Krebs-Ringer bicarbonate buffer solutions and their contractions and relaxations compared. Endothelium-dependent relaxations to acetylcholine (in the presence of meclofenamate or of the thromboxane-prostanoid (TP) receptor antagonist S18886) were comparable at the three pH values tested in contracted aortic or carotid arterial rings. Endothelium-dependent contractions of quiescent carotid arteries were reduced in acidosis and potentiated in alkalosis compared to control; these effects were reversible. The carotid arteries produced equal amounts of 6-keto prostaglandin F1α and thromboxane B2 at the different pH values tested. Contractions to the full TP receptor agonist U46619 were similar in the three milieus, but after inducing partial TP receptor blockade (with low concentrations of the TP receptor antagonist S18886) they were depressed in acidosis compared to alkalosis. Prostacyclin as a partial TP receptor activator also induced weaker contractions at low than at high pH, whereas its vasodilator effect was not affected. These findings demonstrate that changes in pH modulate endothelium-dependent contractions in mouse arteries primarily by altering the sensitivity of TP receptors of vascular smooth muscle to endothelium-derived contracting factors.

Obesity and risk of vascular disease: importance of endothelium-dependent vasoconstriction.

UNLABELLED: Obesity has become a serious global health issue affecting both adults and children. Recent devolopments in world demographics and declining health status of the world's population indicate that the prevalence of obesity will continue to increase in the next decades. As a disease, obesity has deleterious effects on metabolic homeostasis, and affects numerous organ systems including heart, kidney and the vascular system. Thus, obesity is now regarded as an independent risk factor for atherosclerosis-related diseases such as coronary artery disease, myocardial infarction and stroke. In the arterial system, endothelial cells are both the source and target of factors contributing to atherosclerosis. Endothelial vasoactive factors regulate vascular homeostasis under physiological conditions and maintain basal vascular tone. Obesity results in an imbalance between endothelium-derived vasoactive factors favouring vasoconstriction, cell growth and inflammatory activation. Abnormal regulation of these factors due to endothelial cell dysfunction is both a consequence and a cause of vascular disease processes. Finally, because of the similarities of the vascular pathomechanisms activated, obesity can be considered to cause accelerated, 'premature' vascular aging. Here, we will review some of the pathomechanisms involved in obesity-related activation of endothelium-dependent vasoconstriction, the clinical relevance of obesity-associated vascular risk, and therapeutic interventions using 'endothelial therapy' aiming at maintaining or restoring vascular endothelial health. LINKED ARTICLES: This article is part of a themed section on Fat and Vascular Responsiveness. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-3.