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1.
Article En | MEDLINE | ID: mdl-38839108

BACKGROUND: Gender influences cardiovascular disease (CVD) through norms, social relations, roles and behaviours. This study identified gender-specific aspects of socialisation associated with CVD. METHODS: A longitudinal study was conducted, involving 9936 (5,231 women and 4705 men) initially healthy, community-dwelling Australians aged 70 years or more from the ASPirin in Reducing Events in the Elderly (ASPREE) study and ASPREE Longitudinal Study of Older Persons, with a median follow-up time of 6.4 years. Variable categorisation, variable selection (using machine learning (ML) models; Elastic Net and extreme gradient boosting) and Cox-regression were employed separately by binary gender to identity socialisation factors (n=25 considered) associated with CVD. RESULTS: Different socialisation factors were identified using the ML models. In the Cox model, for both genders, being married/partnered was associated with a reduced risk of CVD (men: HR 0.76, 95% CI 0.60 to 0.96; women: HR 0.67, 95% CI 0.58 to 0.95). For men, having 3-8 relatives they felt close to and could call on for help (HR 0.76, 95% CI 0.58 to 0.99; reference <3 relatives), having 3-8 relatives they felt at ease talking with about private matters (HR 0.70, 95% CI 0.55 to 0.90; reference <3 relatives) or playing games such as chess or cards (HR 0.82, 95% CI 0.67 to 1.00) was associated with reduced risk of CVD. For women, living with others (HR 0.71, 95% CI 0.55 to 0.91) or having ≥3 friends they felt at ease talking with about private matters (HR 0.74, 95% CI 0.58 to 0.95; reference <3 friends) was associated with a lower risk of CVD. CONCLUSIONS: This study demonstrates the need to prioritise gender-specific social factors to improve cardiovascular health in older adults.

2.
J Hum Hypertens ; 38(6): 516-522, 2024 Jun.
Article En | MEDLINE | ID: mdl-38744907

Single-pill combination therapy containing four quarter-dose medications for high blood pressure improves BP control compared to monotherapy, however patient-reported acceptance of the quadpill as a treatment strategy remains undescribed. We collected within-trial feedback and interviewed participants from the quadruple ultra-low-dose treatment for hypertension (QUARTET) trial to characterise patient attitudes to this intervention. All trial participants were asked about ease and preference for the quadpill and provided an opportunity to give further comments on the trial at 12 weeks (trial primary endpoint) and 52 weeks extended follow-up. Separately, we used purposive and quota sampling for the semi-structured telephone interviews, with the resultant verbatim transcripts analysed using an inductive thematic analysis approach. Themes were re-evaluated after each successive interview, and at suspected data saturation, an additional interview conducted for confirmation. At 12 weeks follow-up, 502 of 591 (85%) participants responded to acceptability questions, and 359 of 417 (86%) responded at week 52. Most reported the trial capsule easy or very easy to take. From eight sites, 16 participants were interviewed between 5 August 2020 and 19 November 2020. All described a positive experience, preferred once-daily morning dosing and found routine facilitated adherence. Participants valued individual responsibility for adherence, and involvement of the general practitioner in blood-pressure management. Most reported capsule size did not deter adherence but desired a smaller capsule. Participants described a preference for minimising number and dosage of medications, reduced capsule size, and once-daily morning dosing. These findings suggest a preference for single-pill combination therapy for blood pressure lowering.


Antihypertensive Agents , Blood Pressure , Drug Combinations , Hypertension , Humans , Hypertension/drug therapy , Hypertension/physiopathology , Hypertension/diagnosis , Antihypertensive Agents/administration & dosage , Female , Male , Middle Aged , Blood Pressure/drug effects , Aged , Treatment Outcome , Patient Preference , Adult
3.
Magn Reson Med ; 2024 May 04.
Article En | MEDLINE | ID: mdl-38703017

PURPOSE: Magnetization transfer saturation (MTsat) mapping is commonly used to examine the macromolecular content of brain tissue. This study compared variable flip angle (VFA) T1 mapping against compressed-sensing MP2RAGE (csMP2RAGE) T1 mapping for accelerating MTsat imaging. METHODS: VFA, MP2RAGE, and csMP2RAGE were compared against inversion-recovery T1 in an aqueous phantom at 3 T. The same 1-mm VFA, MP2RAGE, and csMP2RAGE protocols were acquired in 4 healthy subjects to compare T1 and MTsat. Bloch-McConnell simulations were used to investigate differences between the phantom and in vivo T1 results. Ten healthy controls were imaged twice with the csMP2RAGE MTsat protocol to quantify repeatability. RESULTS: The MP2RAGE and csMP2RAGE protocols were 13.7% and 32.4% faster than the VFA protocol, respectively. At these scan times, all approaches provided strong repeatability and accurate T1 times (< 5% difference) in the phantom, but T1 accuracy was more impacted by T2 for VFA than for MP2RAGE. In vivo, VFA estimated longer T1 times than MP2RAGE and csMP2RAGE. Simulations suggest that the differences in the T1 measured using VFA, MP2RAGE, and inversion recovery could be explained by the magnetization-transfer effects. In the test-retest experiment, we found that the csMP2RAGE has a minimum detectable change of 2.3% for T1 mapping and 7.8% for MTsat imaging. CONCLUSIONS: We demonstrated that MP2RAGE can be used in place of VFA T1 mapping in an MTsat protocol. Furthermore, a shorter scan time and high repeatability can be achieved using the csMP2RAGE sequence.

4.
Alzheimers Res Ther ; 16(1): 111, 2024 May 18.
Article En | MEDLINE | ID: mdl-38762556

BACKGROUND: Cognitive impairment is common after stroke, and a large proportion of stroke patients will develop dementia. However, there have been few large prospective studies which have assessed cognition both prior to and after stroke. This study aims to determine the extent to which incident stroke impacts different domains of cognitive function in a longitudinal cohort of older community-dwelling individuals. METHODS: 19,114 older individuals without cardiovascular disease or major cognitive impairment were recruited and followed over a maximum 11 years. Stroke included ischaemic and haemorrhagic stroke and was adjudicated by experts. Cognitive function was assessed regularly using Modified Mini-Mental State Examination (3MS), Hopkins Verbal Learning Test-Revised (HVLT-R), Symbol Digit Modalities Test (SDMT), and Controlled Oral Word Association Test (COWAT). Linear mixed models were used to investigate the change in cognition at the time of stroke and decline in cognitive trajectories following incident stroke. RESULTS: During a median follow-up period of 8.4 [IQR: 7.2, 9.6] years, 815 (4.3%) participants experienced a stroke. Over this time, there was a general decline observed in 3MS, HVLT-R delayed recall, and SDMT scores across participants. However, for individuals who experienced a stroke, there was a significantly greater decline across all cognitive domains immediately after the event immediately after the event (3MS: -1.03 [95%CI: -1.45, -0.60]; HVLT-R: -0.47 [-0.70, -0.24]; SDMT: -2.82 [-3.57, -2.08]; COWAT: -0.67 [-1.04, -0.29]) and a steeper long-term decline for three of these domains (3MS -0.62 [-0.88, -0.35]; COWAT: -0.30 [-0.46, -0.14]); HVLT-R: -0.12 [95%CI, -0.70, -0.24]). However individuals with stroke experienced no longer-term decline in SDMT compared to the rest of the participants. CONCLUSIONS: These findings highlight the need for comprehensive neuropsychology assessments for ongoing monitoring of cognition following incident stroke; and potential early intervention.


Cognitive Dysfunction , Neuropsychological Tests , Stroke , Humans , Female , Male , Aged , Stroke/complications , Stroke/psychology , Stroke/epidemiology , Longitudinal Studies , Cognitive Dysfunction/epidemiology , Cognitive Dysfunction/etiology , Cognitive Dysfunction/diagnosis , Incidence , Aged, 80 and over , Cognition/physiology , Prospective Studies
5.
Article En | MEDLINE | ID: mdl-38780425

The transitional epithelial cells (urothelium) that line the lumen of the urinary bladder form a barrier between potentially harmful pathogens, toxins, and other bladder contents and the inner layers of the bladder wall. The urothelium, however, is not simply a passive barrier, as it can produce signaling factors, such as ATP, nitric oxide, prostaglandins and other prostanoids, that can modulate bladder function. We investigated whether select substances produced by the urothelium could directly modulate the contractility of the underlying urinary bladder smooth muscle. Force was measured in isolated strips of mouse urinary bladder with the urothelium intact or denuded. Bladder strips developed spontaneous tone and phasic contractions. In urothelium-intact strips, basal tone, as well as the frequency and amplitude of phasic contractions, were 25%, 32%, and 338% higher than in urothelium-denuded strips, respectively. Basal tone and phasic contractility in urothelium-intact bladder strips were abolished by the cyclooxygenase (COX) inhibitor indomethacin (10 mM) or the voltage-dependent Ca2+ channel blocker diltiazem (50 mM), whereas blocking neuronal sodium channels with tetrodotoxin (1 mM) had no effect. These results suggest that prostanoids produced in the urothelium enhance smooth muscle tone and phasic contractions by activating voltage-dependent Ca2+ channels in the underlying bladder smooth muscle. We went on to demonstrate that blocking COX inhibits the generation of transient pressure events in isolated pressurized bladders and greatly attenuates the afferent nerve activity during bladder filling, suggesting that urothelial prostanoids may also play a role in sensory nerve signaling.

6.
JAMA Ophthalmol ; 2024 May 23.
Article En | MEDLINE | ID: mdl-38780931

Importance: Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss in old age. There is no proven intervention to prevent AMD and, apart from lifestyle, nutritional, and supplement advice, there is no intervention to delay its progression. Objective: To determine the impact of long-term low-dose aspirin on the incidence and progression of AMD. Design, Setting and Participants: The Aspirin in Reducing Events in the Elderly-AMD (ASPREE-AMD) study was an Australian-based substudy of the ASPREE trial, a multicenter, international, randomized, double-masked, placebo-clinical trial investigating the efficacy of low-dose aspirin in prolonging disability-free survival among older individuals. Retinal photography was conducted at baseline from March 2010 to January 2015, then 3 and 5 years after randomization. AMD status was determined using color retinal images and treatment records. Australian participants in ASPREE aged 70 years and older without dementia, independence-limiting physical disability, cardiovascular disease, or chronic illness limiting 5-year survival and with gradable retinal images at baseline were included. Data were analyzed from December 2022 to December 2023. Interventions: Aspirin (100 mg daily, enteric coated) or placebo. Main Outcomes and Measures: Incidence of AMD and progression from early/intermediate to late AMD. Outcomes were analyzed by modified intention-to-treat analysis. Results: A total of 4993 participants were enrolled in this substudy. Baseline characteristics were similar between groups. At the time of sponsor-determined trial termination, retinal follow-up data were available for 3208 participants, 3171 of whom were analyzed for AMD incidence and progression, with a median (IQR) age of 73.5 (71.5-76.4) years and even sex distribution (1619 [51%] female). Median (IQR) follow-up time was 3.1 (3.0-3.5) years. Cumulative AMD incidence was 195 of 1004 (19.4%) in the aspirin group and 187 of 979 (19.1%) in the placebo group (relative risk [RR], 1.02; 95% CI, 0.85-1.22; P = .86). Cumulative progression from early/intermediate AMD to late AMD was observed in 14 of 615 (2.3%) participants in the aspirin group and 18 of 573 (3.1%) in the placebo group (RR, 0.72; 95% CI, 0.36-1.44; P = .36). Conclusions and Relevance: In this trial, low-dose aspirin administered for 3 years did not affect the incidence of AMD. The evidence was weaker for progression of AMD due to low number of progressed cases. Overall, these results do not support suggestion that low-dose daily aspirin prevents the development or progression of AMD. Trial Registration: anzctr.org Identifier: ACTRN12613000755730.

7.
Aust Prescr ; 47(2): 57-63, 2024 Apr.
Article En | MEDLINE | ID: mdl-38737366

The outdated cardiovascular disease risk calculator has been reported to overestimate cardiovascular disease risk for a contemporary Australian population, and does not include relevant variables, such as socioeconomic disadvantage, which has been shown to increase the incidence of both heart attack and stroke. The 2023 Australian Guideline for Assessing and Managing Cardiovascular Disease Risk marks a major milestone as the first update to Australia's cardiovascular disease prevention guideline in over a decade. The new guideline may help to refine and recategorise risk estimates, hence improving the discriminatory and predictive value of the new calculator. The new Australian Cardiovascular Disease Risk Calculator expresses risk scores as a percentage estimate of a person's probability of dying or being hospitalised due to cardiovascular disease within the next 5 years. The new calculator expresses risk scores as low (less than 5%), intermediate (5% to less than 10%), or high (10% or higher) risk over 5 years. Reclassification factors built into the new calculator are designed to help clinicians individualise risk estimates. These factors include ethnicity (e.g. First Nations status), family history of premature cardiovascular disease, severe mental illness, kidney disease and coronary artery calcium score. The new calculator also uses optional diabetes-specific variables (supporting a more granular cardiovascular disease risk assessment of people with type 2 diabetes). People who meet the clinically determined high-risk criteria (chronic kidney disease, familial hypercholesterolaemia) should not progress through the Australian Cardiovascular Disease risk calculator, but move straight to management. For a person with a cardiovascular disease risk score recorded from the outdated calculator, clinicians may want to reassess their risk using the new calculator the next time the person attends.

8.
Chaos ; 34(4)2024 Apr 01.
Article En | MEDLINE | ID: mdl-38629791

Numerical continuation is used to compute solution branches in a two-component reaction-diffusion model of Leslie-Gower type. Two regimes are studied in detail. In the first, the homogeneous state loses stability to supercritical spatially uniform oscillations, followed by a subcritical steady state bifurcation of Turing type. The latter leads to spatially localized states embedded in an oscillating background that bifurcate from snaking branches of localized steady states. Using two-parameter continuation, we uncover a novel mechanism whereby disconnected segments of oscillatory states zip up into a continuous snaking branch of time-periodic localized states, some of which are stable. In the second, the homogeneous state loses stability to supercritical Turing patterns, but steady spatially localized states embedded either in the homogeneous state or in a small amplitude Turing state are nevertheless present. We show that such behavior is possible when sideband Turing states are strongly subcritical and explain why this is so in the present model. In both cases, the observed behavior differs significantly from that expected on the basis of a supercritical primary bifurcation.

9.
Fam Med Community Health ; 12(Suppl 3)2024 Apr 12.
Article En | MEDLINE | ID: mdl-38609090

Storylines of Family Medicine is a 12-part series of thematically linked mini-essays with accompanying illustrations that explore the many dimensions of family medicine as interpreted by individual family physicians and medical educators in the USA and elsewhere around the world. In 'VII: family medicine across the lifespan', authors address the following themes: 'Family medicine maternity care', 'Seeing children as patients brings joy to work', 'Family medicine and the care of adolescents', 'Reproductive healthcare across the lifespan', 'Men's health', 'Care of older adults', and 'Being with dying'. May readers appreciate the range of family medicine in these essays.


Family Practice , Maternal Health Services , Pregnancy , Adolescent , Child , Humans , Female , Aged , Longevity , Physicians, Family , Health Facilities
10.
Patient Educ Couns ; 125: 108299, 2024 Aug.
Article En | MEDLINE | ID: mdl-38657560

OBJECTIVES: Low health literacy is associated with worse health outcomes, including for cardiovascular disease (CVD). However, general practitioners (GPs) have limited support to identify and address patient health literacy needs in CVD prevention consultations. This study explored GPs' experiences of patient health literacy needs during CVD risk assessment and management consultations. METHODS: Semi-structured interviews with 18 GPs in Tasmania, Australia in 2021. A Framework Analysis approach was used to code transcripts to a thematic framework. RESULTS: GPs perceptions on patient health literacy informed three themes: 1. Methods of estimating health literacy; 2. GPs' perceptions about the impact of health literacy on CVD prevention including risk factor knowledge and behaviours; and 3. Strategies for communicating with patients experiencing health literacy challenges. The findings show that while no formal tools were used to assess health literacy in this sample, perceived health literacy can change GPs' communication and prevention strategies. CONCLUSION: The findings raise concerns about the equity of choices made available to patients, based on subjective perceptions of their health literacy level. PRACTICE IMPLICATION: GPs could be better supported to assess and address patient health literacy needs in CVD prevention consultations.


Cardiovascular Diseases , General Practitioners , Health Literacy , Interviews as Topic , Physician-Patient Relations , Qualitative Research , Referral and Consultation , Humans , Cardiovascular Diseases/prevention & control , Male , Female , Middle Aged , Adult , Tasmania , Health Knowledge, Attitudes, Practice , Communication , Attitude of Health Personnel
11.
Med J Aust ; 220(9): 482-490, 2024 May 20.
Article En | MEDLINE | ID: mdl-38623719

INTRODUCTION: The 2023 Australian guideline for assessing and managing cardiovascular disease risk provides updated evidence-based recommendations for the clinical assessment and management of cardiovascular disease (CVD) risk for primary prevention. It includes the new Australian CVD risk calculator (Aus CVD Risk Calculator), based on an equation developed from a large New Zealand cohort study, customised and recalibrated for the Australian population. The new guideline replaces the 2012 guideline that recommended CVD risk assessment using the Framingham risk equation. MAIN RECOMMENDATIONS: The new guideline recommends CVD risk assessment in people without known CVD: all people aged 45-79 years, people with diabetes from 35 years, and First Nations people from 30 years. The new Aus CVD Risk Calculator should be used to estimate and categorise CVD risk into low (< 5% risk over five years), intermediate (5% to < 10% risk over five years) or high risk (≥ 10% over five years). The following reclassification factors may be applied to recategorise calculated risk to improve accuracy of risk prediction, particularly in individuals close to a risk threshold: Indigenous status/ethnicity, estimated glomerular filtration rate, urine albumin to creatinine ratio measurements, severe mental illness, coronary artery calcium score and family history of premature CVD. A variety of communication formats is available to communicate CVD risk to help enable shared decision making. Healthy lifestyle modification, including smoking cessation, nutrition, physical activity and limiting alcohol, is encouraged for all individuals. Blood pressure-lowering and lipid-modifying pharmacotherapies should be prescribed for high risk and considered for intermediate risk individuals, unless contraindicated or clinically inappropriate. Reassessment of CVD risk should be considered within five years for individuals at low risk and within two years for those with intermediate risk. Reassessment of CVD risk is not recommended for individuals at high risk. CHANGES IN ASSESSMENT AND MANAGEMENT AS A RESULT OF THE GUIDELINE: The updated guideline recommends assessment over a broader age range and uses the Aus CVD Risk Calculator, which replaces the previous Framingham-based equation. It incorporates new variables: social disadvantage, diabetes-specific risk markers, diagnosis of atrial fibrillation and use of blood pressure-lowering and lipid-modifying therapies. Reclassification factors are also a new addition. Updated risk categories and thresholds are based on the new Aus CVD Risk Calculator. The proportion of the population in the high risk category (≥ 10% over five years) is likely to be broadly comparable to more than 15% risk from the Framingham-based equation. The full guideline and Aus CVD Risk Calculator can be accessed at www.cvdcheck.org.au.


Cardiovascular Diseases , Humans , Cardiovascular Diseases/prevention & control , Cardiovascular Diseases/therapy , Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/epidemiology , Australia , Risk Assessment/methods , Middle Aged , Aged , Female , Male , Heart Disease Risk Factors , Practice Guidelines as Topic , Primary Prevention , Adult
12.
Neuroepidemiology ; 2024 Mar 06.
Article En | MEDLINE | ID: mdl-38447549

INTRODUCTION: There is limited evidence about the management of cardiovascular risk factors within 12 months before stroke/transient ischaemic attack (TIA) in Australian general practices. We evaluated whether age and sex disparities in cardiovascular risk factor management for primary prevention exist in general practice. METHODS: A retrospective cohort study using data from the Australian Stroke Clinical Registry (2014-2018) linked with general practice data from three primary health networks in Victoria, Australia. We included adults who had ≥2 encounters with a general practitioner within 12 months immediately before the first stroke/TIA. Cardiovascular risk factor management within 12 months before stroke/TIA was evaluated in terms of: assessment of risk factors (blood pressure [BP], serum lipids, blood glucose, body weight); prescription of prevention medications (BP, lipid-, glucose-lowering, antithrombotic agents); and attainment of risk factor targets. RESULTS: Of 2,880 patients included (median age 76.5 years, 48.4% women), 80.9% were assessed for BP, 49.9% serum lipids, 46.8% blood glucose, and 39.3% body weight. Compared to patients aged 65-84 years, those aged <65 or ≥85 years were less often assessed for risk factors, with women aged ≥85 years assessed for significantly fewer risk factors than their male counterparts. The most prescribed prevention medications were BP-lowering (64.9%) and lipid-lowering agents (42.0%). There were significant sex differences among those aged <65 years (34.7% women vs. 40.2% men) and ≥85 years (34.0% women vs. 44.3% men) for lipid-lowering agents. Risk factor target attainment was generally poorer in men than women, especially among those aged <65 years. CONCLUSION: Age-sex disparity exists in risk factor management for primary prevention in general practice, and this was more pronounced among younger patients and older women.

13.
Hypertension ; 81(5): 1087-1094, 2024 May.
Article En | MEDLINE | ID: mdl-38477128

BACKGROUND: Low-dose combinations are a promising intervention for improving blood pressure (BP) control but their effects on therapeutic inertia are uncertain. METHODS: Analysis of 591 patients randomized to an ultra-low-dose quadruple pill or initial monotherapy. The episode of therapeutic inertia was defined as a patient visit with a BP of >140/90 mm Hg without intensification of antihypertensive treatment. We compared the frequency of therapeutic inertia episodes between Quadpill and initial monotherapy as a proportion of the total population (intention-to-treat analysis with the denominator being all participants randomized) and as a proportion of people with uncontrolled BP (with the denominator being participants with uncontrolled BP). RESULTS: Therapeutic inertia occurred in fewer participants randomized to Quadpill compared with monotherapy. For example, among the 390 participants with a 6-month follow-up, therapeutic inertia according to unattended BP was 21/192 (11%) versus 45/192 (23%), P=0.002. There were similar rates of therapeutic inertia among those with uncontrolled unattended BP in each group (all P>0.4). Consistent observations were seen with the use of attended office BP measures. The major determinants of not intensifying treatment during follow-up were BP readings that were close to target and large improvements in BP compared with the previous visit. CONCLUSIONS: Among all treated individuals, low-dose Quadpill reduced the number of therapeutic inertia episodes compared with initial monotherapy. After the first follow-up visit, most high BP values did not lead to treatment intensification in both groups. Education is needed about the importance of treatment intensification despite a significant improvement in BP or BP being close to target. REGISTRATION: URL: https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=ACTRN12616001144404; Unique identifier: ACTRN12616001144404.


Hypertension , Humans , Antihypertensive Agents/therapeutic use , Blood Pressure , Combined Modality Therapy , Medication Adherence
14.
Article En | MEDLINE | ID: mdl-38426788

BACKGROUND: Aging increases fracture risk through bone loss and microarchitecture deterioration due to an age-related imbalance in bone resorption and formation during bone remodelling. We examined the associations between levels of phosphate, calcium, and alkaline phosphatase, and fracture risk in initially-healthy older individuals. METHODS: A post-hoc analysis of the Aspirin in Reducing Events in the Elderly (ASPREE) trial recruited 16,703 Australian participants aged ≥70 years and 2,411 US participants aged ≥65 years. Analyses were conducted on ASPREE-Fracture substudy participants from Australia with serum calcium, phosphate, and alkaline phosphatase measurement. Fracture data were collected post-randomization. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CIs). Phosphate, calcium, and alkaline phosphatase were analysed in deciles (D1-D10), with deciles 4-7 (31-70%) as the reference category. Restricted cubic spline curves were used to identify nonlinear associations. RESULTS: Of the 9915 participants, 907 (9·2%) persons had incident fractures recorded over 3·9 (SD 1·4) years. In the fully adjusted model, males in the top decile (D10) of phosphate had 78% higher risk of incident fracture (HR 1·78, 95% CI 1·25-2·54). No such association was observed for females (HR 1·09, 95% CI 0·83-1·44). The population attributable fraction in men within the D10 phosphate category is 6·9%. CONCLUSION: This result confirms that, high-normal serum phosphate levels are associated with increased fracture risk in older men.

15.
Biophys J ; 2024 Mar 05.
Article En | MEDLINE | ID: mdl-38444160

Capillaries, composed of electrically coupled endothelial cells and overlying pericytes, constitute the vast majority of blood vessels in the brain. The most arteriole-proximate three to four branches of the capillary bed are covered by α-actin-expressing, contractile pericytes. These mural cells have a distinctive morphology and express different markers compared with their smooth muscle cell (SMC) cousins but share similar excitation-coupling contraction machinery. Despite this similarity, pericytes are considerably more depolarized than SMCs at low intravascular pressures. We have recently shown that pericytes, such as SMCs, possess functional voltage-dependent Ca2+ channels and ATP-sensitive K+ channels. Here, we further investigate the complement of pericyte ion channels, focusing on members of the K+ channel superfamily. Using NG2-DsRed-transgenic mice and diverse configurations of the patch-clamp technique, we demonstrate that pericytes display robust inward-rectifier K+ currents that are primarily mediated by the Kir2 family, based on their unique biophysical characteristics and sensitivity to micromolar concentrations of Ba2+. Moreover, multiple lines of evidence, including characteristic kinetics, sensitivity to specific blockers, biophysical attributes, and distinctive single-channel properties, established the functional expression of two voltage-dependent K+ channels: KV1 and BKCa. Although these three types of channels are also present in SMCs, they exhibit distinctive current density and kinetics profiles in pericytes. Collectively, these findings underscore differences in the operation of shared molecular features between pericytes and SMCs and highlight the potential contribution of these three K+ ion channels in setting pericyte membrane potential, modulating capillary hemodynamics, and regulating cerebral blood flow.

16.
J Hypertens ; 42(6): 1009-1018, 2024 Jun 01.
Article En | MEDLINE | ID: mdl-38501351

BACKGROUND: A combination of four ultra-low-dose blood pressure (BP) medications lowered office BP more effectively than initial monotherapy in the QUARTET trial. The effects on average ambulatory BP changes at 12 weeks have not yet been reported in detail. METHODS: Adults with hypertension who were untreated or on monotherapy were eligible for participation. Overall, 591 participants were randomized to either the quadpill (irbesartan 37.5 mg, amlodipine 1.25 mg, indapamide 0.625 mg, and bisoprolol 2.5 mg) or monotherapy control (irbesartan 150 mg). The difference in 24-h, daytime, and night-time systolic and diastolic ambulatory BP at 12 weeks along further metrics were predefined secondary outcomes. RESULTS: Of 576 participants, 289 were randomized to the quadpill group and 287 to the monotherapy group. At 12 weeks, mean 24-h ambulatory SBP and DBP were 7.7 [95% confidence interval (95% CI) 9.6-5.8] and 5.3 (95% CI: 6.5-4.1) mmHg lower in the quadpill vs. monotherapy group ( P  < 0.001 for both). Similar reductions in the quadpill group were observed for daytime (8.1/5.7 mmHg lower) and night-time (6.3/4.0 mmHg lower) BP at 12 weeks (all P  < 0.001) compared to monotherapy. The rate of BP control (24-h average BP < 130/80 mmHg) at 12 weeks was higher in the quadpill group (77 vs. 50%; P  < 0.001). The reduction in BP load was also more pronounced with the quadpill. CONCLUSION: A quadruple quarter-dose combination compared with monotherapy resulted in greater ambulatory BP lowering across the entire 24-h period with higher ambulatory BP control rates and reduced BP variability at 12 weeks. These findings further substantiate the efficacy of an ultra-low-dose quadpill-based BP lowering strategy.


Antihypertensive Agents , Blood Pressure Monitoring, Ambulatory , Blood Pressure , Drug Therapy, Combination , Hypertension , Humans , Antihypertensive Agents/administration & dosage , Antihypertensive Agents/therapeutic use , Blood Pressure Monitoring, Ambulatory/methods , Male , Blood Pressure/drug effects , Female , Middle Aged , Hypertension/drug therapy , Hypertension/physiopathology , Aged , Bisoprolol/administration & dosage , Bisoprolol/therapeutic use , Amlodipine/administration & dosage , Adult , Indapamide/administration & dosage , Indapamide/therapeutic use
17.
J Clin Invest ; 134(8)2024 Feb 22.
Article En | MEDLINE | ID: mdl-38386425

Loss of arterial smooth muscle cells (SMCs) and abnormal accumulation of the extracellular domain of the NOTCH3 receptor (Notch3ECD) are the 2 core features of CADASIL, a common cerebral small vessel disease caused by highly stereotyped dominant mutations in NOTCH3. Yet the relationship between NOTCH3 receptor activity, Notch3ECD accumulation, and arterial SMC loss has remained elusive, hampering the development of disease-modifying therapies. Using dedicated histopathological and multiscale imaging modalities, we could detect and quantify previously undetectable CADASIL-driven arterial SMC loss in the CNS of mice expressing the archetypal Arg169Cys mutation. We found that arterial pathology was more severe and Notch3ECD accumulation greater in transgenic mice overexpressing the mutation on a wild-type Notch3 background (TgNotch3R169C) than in knockin Notch3R170C/R170C mice expressing this mutation without a wild-type Notch3 copy. Notably, expression of Notch3-regulated genes was essentially unchanged in TgNotch3R169C arteries. We further showed that wild-type Notch3ECD coaggregated with mutant Notch3ECD and that elimination of 1 copy of wild-type Notch3 in TgNotch3R169C was sufficient to attenuate Notch3ECD accumulation and arterial pathology. These findings suggest that Notch3ECD accumulation, involving mutant and wild-type NOTCH3, is a major driver of arterial SMC loss in CADASIL, paving the way for NOTCH3-lowering therapeutic strategies.


CADASIL , Mice , Animals , Receptor, Notch3/genetics , CADASIL/genetics , CADASIL/metabolism , CADASIL/pathology , Protein Aggregates , Receptors, Notch/genetics , Receptors, Notch/metabolism , Arteries/pathology , Mice, Transgenic , Mutation
19.
Neuroepidemiology ; 58(3): 156-165, 2024.
Article En | MEDLINE | ID: mdl-38359812

INTRODUCTION: Evidence on the cost-effectiveness of comprehensive post-stroke programs is limited. We assessed the cost-effectiveness of an individualised management program (IMP) for stroke or transient ischaemic attack (TIA). METHODS: A cost-utility analysis alongside a randomised controlled trial with a 24-month follow-up, from both societal and health system perspectives, was conducted. Adults with stroke/TIA discharged from hospitals were randomised by primary care practice to receive either usual care (UC) or an IMP in addition to UC (intervention). An IMP included stroke-specific nurse-led education and a specialist review of care plans at baseline, 3 months, and 12 months, and telephone reviews by nurses at 6 months and 18 months. Costs were expressed in 2021 Australian dollars (AUD). Costs and quality-adjusted life years (QALYs) beyond 12 months were discounted by 5%. The probability of cost-effectiveness of the intervention was determined by quantifying 10,000 bootstrapped iterations of incremental costs and QALYs below the threshold of AUD 50,000/QALY. RESULTS: Among the 502 participants (65% male, median age 69 years), 251 (50%) were in the intervention group. From a health system perspective, the incremental cost per QALY gained was AUD 53,175 in the intervention compared to the UC group, and the intervention was cost-effective in 46.7% of iterations. From a societal perspective, the intervention was dominant in 52.7% of iterations, with mean per-person costs of AUD 49,045 and 1.352 QALYs compared to mean per-person costs of AUD 51,394 and 1.324 QALYs in the UC group. The probability of the cost-effectiveness of the intervention, from a societal perspective, was 60.5%. CONCLUSIONS: Care for people with stroke/TIA using an IMP was cost-effective from a societal perspective over 24 months. Economic evaluations of prevention programs need sufficient time horizons and consideration of costs beyond direct healthcare utilisation to demonstrate their value to society.


Cost-Benefit Analysis , Quality-Adjusted Life Years , Stroke , Humans , Male , Female , Aged , Stroke/economics , Stroke/therapy , Middle Aged , Australia , Ischemic Attack, Transient/economics , Ischemic Attack, Transient/therapy , Aged, 80 and over
20.
J Cereb Blood Flow Metab ; 44(5): 680-688, 2024 May.
Article En | MEDLINE | ID: mdl-38420777

The accumulation of the microtubule-associated tau protein in and around blood vessels contributes to brain microvascular dysfunction through mechanisms that are incompletely understood. Delivery of nutrients to active neurons in the brain relies on capillary calcium (Ca2+) signals to direct blood flow. The initiation and amplification of endothelial cell Ca2+ signals require an intact microtubule cytoskeleton. Since tau accumulation in endothelial cells disrupts native microtubule stability, we reasoned that tau-induced microtubule destabilization would impair endothelial Ca2+ signaling. We tested the hypothesis that tau disrupts the regulation of local cerebral blood flow by reducing endothelial cell Ca2+ signals and endothelial-dependent vasodilation. We used a pathogenic soluble tau peptide (T-peptide) model of tau aggregation and mice with genetically encoded endothelial Ca2+ sensors to measure cerebrovascular endothelial responses to tau exposure. T-peptide significantly attenuated endothelial Ca2+ activity and cortical capillary blood flow in vivo. Further, T-peptide application constricted pressurized cerebral arteries and inhibited endothelium-dependent vasodilation. This study demonstrates that pathogenic tau alters cerebrovascular function through direct attenuation of endothelial Ca2+ signaling and endothelium-dependent vasodilation.


Calcium Signaling , Cerebrovascular Circulation , Microvessels , Vasodilation , tau Proteins , Animals , Vasodilation/drug effects , Calcium Signaling/drug effects , Mice , tau Proteins/metabolism , Microvessels/metabolism , Microvessels/drug effects , Cerebrovascular Circulation/drug effects , Cerebrovascular Circulation/physiology , Brain/blood supply , Brain/metabolism , Endothelial Cells/metabolism , Endothelial Cells/drug effects , Male , Endothelium, Vascular/metabolism , Endothelium, Vascular/drug effects , Calcium/metabolism
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