Alterations in leukocyte beta-receptor affinity with aging. A potential explanation for altered beta-adrenergic sensitivity in the elderly

Optimization of GDMT for patients with heart failure and reduced ejection fraction: can physiological and biological barriers explain the gaps in adherence to heart failure guidelines?

Heart failure is a growing epidemic with high mortality rates and recurrent hospital admissions that creates a burden on affected individuals, their caregivers and the whole healthcare system. Throughout the years, many randomized trials have established the effectiveness of several pharmacological therapies and electrophysiological devices to reduce hospitalizations and improve quality of life and survival, mostly for patients with heart failure with reduced ejection fraction (HFrEF). These studies led to the publication of national societies' recommendations to guide clinicians in the management of HFrEF. Yet, many reports have shown significant care gaps in adherence to these recommendations in clinical practice, highlighting suboptimal use and/or dosing of evidence-based therapies. Adherence to guidelines has been shown to be associated with the best prognosis in HFrEF, with patients presenting with intolerances or contraindications having the highest risk of events; however, it remains unclear whether this association is causal or merely a marker of more advanced disease. Furthermore, individual characteristics may limit the possibility of reaching the targeted dosage of specific agents. Herein, we provide a comprehensive overview of clinicians' adherence to heart failure guidelines in a specialized real-life setting, particularly regarding use and optimization of guideline-derived medical therapies, as well as the implementation of more recent agents such as sacubitril/valsartan and SGLT2 inhibitors. We seek potential explanations for suboptimal treatment and its impact on patient outcomes.

Effect of Exercise on Acute Senescent Lymphocyte Counts: A Systematic Review and Meta-Analysis

BACKGROUND

Highly differentiated, senescent lymphocytes are pro-inflammatory and contribute to age-related systemic inflammation, called inflammageing. There are several reports of acute changes in senescent lymphocyte counts post exercise, which potentially have consequences for systemic inflammation. However, there is little consensus since the studies differ with respect to participants, exercise protocols, cellular markers assessed, and the time point of assessment post exercise.

OBJECTIVE

We performed a systematic review and meta-analysis to assess the impact of exercise on senescent lymphocyte counts in blood immediately, 1 h and 2 h post exercise.

METHODS

The search was performed in PubMed (MEDLINE), Web of Science, Embase, Scopus, and Cochrane, on January 11, 2021. The 13 studies selected tested aerobic exercise effects, mainly in young men. They assessed the counts of lymphocytes (CD4 T cells, CD8 T cells, and NK cells), with the following immune cell marker combinations: KLRG1+, CD57+ (only NK cells), EMRA T cells (CD45RA+CCR7-CD28-CD27-), CD28-CD27-, KLRG1+CD28-, and CD28-. Independent extraction of articles was done by 2 researchers.

RESULTS

Standardized mean difference (SMD) and 95% confidence interval between baseline and post exercise showed significant increase (SMD >0.9, p < 0.003) in all types of senescent lymphocytes counts immediately post exercise. At 1 h post exercise, senescent CD4 T cells returned to baseline values (p = 0.74), CD8 T cells were reduced (-0.26 [-0.41; -0.11], p = 0.001), and senescent NK cells were raised (0.62 [0.14; 1.10], p = 0.01) above baseline. By 2 h post exercise, senescent CD4 T cells were reduced (-0.94 [-1.40; -0.48], p < 0.001), CD8 T cells remained below baseline (-0.53 [-1.04; -0.009], p = 0.04), and NK cells had returned to baseline values (-0.29 [-0.64; 0.07], p = 0.11). The main determinants of heterogeneity between studies were cytomegalovirus (CMV) serostatus and the characteristics of exercise protocols. CMV+ individuals had a higher immediate lymphocytosis and 1 h post lymphopenia than CMV- individuals. Exercise performed at higher intensities and shorter durations led to higher magnitude of change in senescent lymphocyte counts at all time-points.

CONCLUSION

The differing effects of exercise on senescent NK cells and CD4 and CD8 T cells suggest differing susceptibility to factors modulating lymphocyte extravasation such as adrenaline and exercise intensity.

Exercise and adrenergic regulation of immunity

Exercise training has a profound impact on immunity, exerting a multitude of positive effects in indications such as immunosenescence, cancer, viral infections and inflammatory diseases. The immune, endocrine and central nervous systems work in a highly synergistic manner and it has become apparent that catecholamine signaling through leukocyte β-adrenergic receptors (β-ARs) is a key mechanism by which exercise mediates improvements in immune function to help mitigate numerous disease conditions. Central to this is the preferential mobilization and redistribution of effector lymphocytes with potent anti-viral and anti-tumor activity, their interaction with muscle-derived cytokines, and the effects of catecholamine signaling on mitochondrial biogenesis, immunometabolism and the resulting inflammatory response. Here, we review the impact of acute and chronic exercise on adrenergic regulation of immunity in the context of aging, cancer, viral infections and inflammatory disease. We also put forth our contention that exercise interventions designed to improve immunity, prevent disease and reduce inflammation should consider the catecholamine-AR signaling axis as a therapeutic target and ask whether or not the adrenergic signaling machinery can be 'trained' to improve immune responses to stress, disease or during the normal physiological process of aging. Finally, we discuss potential strategies to augment leukocyte catecholamine signaling to boost the effects of exercise on immunity in individuals with desensitized β-ARs or limited exercise tolerance.

Prognostic impacts of β-blockers in acute coronary syndrome patients without heart failure treated by percutaneous coronary intervention

BACKGROUND

The use of β-blockers for acute coronary syndrome (ACS) patients without heart failure (HF) is controversial, and lacks of evidence in the era of reperfusion and intensive secondary preventions. This study aimed to investigate the prognostic impacts of β-blockers on patients with ACS but no HF treated by percutaneous coronary intervention (PCI).

METHODS

A total of 2397 consecutive patients with ACS but no HF treated by PCI were retrospectively recruited from January 2010 to June 2017. Univariable Cox regression was used to assess the prognostic impacts of β-blockers, followed by adjusted analysis, one-to-one propensity score matching (PSM), and inverse probability treatment weighting (IPTW) analysis, in order to control for systemic between-group differences. The primary outcome was all-cause death.

RESULTS

Among the included patients, 2060 (85.9%) were prescribed with β-blockers at discharge. The median follow-up time was 727 (433-2016) days, with 55 (2.3%) cases of all-cause death. Unadjusted analysis showed that the use of β-blockers was associated with lower risk of death (hazard ratio [HR]: 0.42, 95% confidence interval [CI]: 0.23-0.76, P = 0.004), which was sustained in adjusted analysis (HR: 0.53, 95% CI: 0.29-0.98, P = 0.044), PSM analysis (HR: 0.44, 95% CI: 0.20-0.96, P = 0.039) and IPTW analysis (HR: 0.49. 95% CI: 0.35-0.70, P < 0.001). Risk reduction was also seen in β-blocker users for cardiac death, but not for major adverse cardiovascular events.

CONCLUSIONS

The use of β-blockers was associated with reduced long-term mortality for ACS-PCI patients without HF.

Topical β-blockers for pyogenic granulomas: A promising option for younger patients

BACKGROUND

Topical β-blockers, propranolol, and timolol were used for pyogenic granuloma (PG) treatment; however, their efficacies and safety profiles were not compared.

AIMS

The aim was to evaluate the safety and efficacy of propranolol 1% and timolol 0.5% creams in the treatment of pyogenic granulomas.

PATIENTS

The study included 30 PG patients. They were divided into three groups (10 patients each). Group I patients received propranolol 1% cream. Group II patients used timolol 0.5% l cream. Group III patients used placebo cream. Creams were applied twice daily for 2 months. Patients were followed up for 3 months to detect any recurrence.

RESULTS

Complete resolution was reported in 6 patients of groups I and II, while none of the control patients reported complete resolution. Despite the absent change in lesions' size in 40% of β-blockers treated groups, they all reported decreased bleeding tendency. There was insignificant difference between the clinical responses between β-blockers groups. No recurrence was reported in any of the patients who achieved complete resolution after 3 months of follow-up. Younger patients respond better to β-blockers. Three patients were deteriorated on beta-blockers treatment.

CONCLUSION

β-blockers are a promising PG treatment option in cases where invasive modalities are not desirable especially in younger patients.

Tiotropium Respimat Efficacy and Safety in Asthma: Relationship to Age

BACKGROUND

Data are limited on the differential response to long-acting bronchodilators in older versus younger adults with asthma.

OBJECTIVE

To determine whether the response to tiotropium Respimat differed in older versus younger patients with asthma.

METHODS

Post hoc analyses of 4 randomized, double-blind, placebo-controlled studies in adults with asthma were carried out. Two studies compared tiotropium Respimat 5 μg once daily with placebo, both added to high-dose inhaled corticosteroid (ICS) plus long-acting β₂-agonist (ie, severe asthma). The other 2 evaluated tiotropium Respimat 2.5 or 5 μg once daily, salmeterol 50 μg twice daily, or placebo, all added to medium-dose ICS (moderate asthma). Data were analyzed in 2 pools: (1) severe and (2) moderate asthma. Efficacy end points: trough and peak FEV₁; trough forced vital capacity; Asthma Control Questionnaire total score and responder percentage, all at week 24. One set of analyses was performed with age as a continuous covariate; the second was conducted in categories less than 40, 40 to 60, and more than 60 years, with treatment-by-age subgroup interaction P values obtained. Safety was analyzed in age categories.

RESULTS

Across the age categories, treatment-by-age subgroup interaction P values for trough FEV₁ were .13 and .77 for patients with severe and moderate asthma, respectively, not indicating significant impact of age on overall treatment effect, with this observation replicated in the 2 continuum analyses. The other end points (including safety) were also not impacted by age.

CONCLUSIONS

Once-daily tiotropium Respimat add-on to ICS or ICS/long-acting β₂-agonist therapy was effective and well tolerated in patients with asthma independent of age.

Heart failure treatment up-titration and outcome and age: an analysis of BIOSTAT-CHF

AIMS

Several studies have shown that older patients with heart failure with reduced ejection fraction (HFrEF) are undertreated. The aim of this study was to evaluate the association of up-titration of angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB) and beta-blockers on outcome across the age spectrum in HFrEF patients.

METHODS AND RESULTS

We analysed HFrEF patients on sub-optimal doses of ACEI/ARB and/or beta-blockers from the BIOSTAT-CHF study stratified by age. Patients underwent a 3-month up-titration period. We used inverse probability weighting to adjust for the likelihood of successful up-titration to determine the association of achieved dose with mortality and/or heart failure hospitalisation, testing for an interaction with age. Over a median follow-up of 21 months in 1720 HFrEF patients (76.5% male, mean age 67 years), the primary outcome occurred in 558 patients. Increased percentage of target dose of ACEI/ARB and beta-blocker achieved at 3 months were both significantly associated with reduced incidence of the primary outcome, [ACEI-ARB: hazard ratio (HR) per 12.5% increase in dose: 0.92, 95% confidence interval (CI) 0.91-0.94, P < 0.001; beta-blocker: HR 0.98, 95% CI 0.95-1.00, P = 0.046], with a significant interaction with age seen for beta-blockers but not ACEI/ARB (P = 0.034 and P = 0.22, respectively).

CONCLUSIONS

Achieving higher doses of ACEI/ARB was associated with improved outcome regardless of age. However, achieving higher doses of beta-blockers was only associated with improved outcome in younger, but not in older patients.

β2-Adrenergic receptor signaling mediates the preferential mobilization of differentiated subsets of CD8+ T-cells, NK-cells and non-classical monocytes in response to acute exercise in humans

Acute exercise preferentially mobilizes cytotoxic T-cells, NK-cells and non-classical monocytes to the bloodstream under the influence of hemodynamic forces and/or β₂-adrenergic receptor (β₂-AR) signaling. However, the relative contribution of these mechanisms to the redeployment of the most exercise-responsive cell types is largely unknown. We determined the lymphocyte and monocyte subtypes mobilized to blood during exercise via β₂-AR signaling whilst controlling for β₁-AR mediated reductions in hemodynamic forces. In a randomized, double blind, complete cross-over design, 14 healthy cyclists exercised for 30-minutes at +10% of blood lactate threshold after ingesting: (1) a placebo, (2) a β₁-preferential antagonist (10 mg bisoprolol), or (2) a non-preferential β₁ + β₂-antagonist (80 mg nadolol) across three trials separated by >7-days. Bisoprolol was administered to reduce hemodynamic forces (heart rate and blood pressure) during exercise to levels comparable with nadolol but without blocking β₂-ARs. The mobilization of total NK-cells, terminally differentiated (CD57+) NK-cells, central memory, effector memory and CD45RA+ effector memory CD8+ T-cells; non-classical monocytes; and γδ T-cells were significantly blunted or abrogated under nadolol compared to both bisoprolol and placebo, indicating that the exercise-induced mobilization of these cell types to the blood is largely influenced by β₂-AR signaling. Nadolol failed to inhibit the mobilization of classical monocytes, CD4+ T-cells (and their subsets) or naïve CD8+ T-cells, indicating that these cell types are mobilized with exercise independently of the β₂-AR. We conclude that the preferential mobilization of NK-cells, non-classical monocytes and differentiated subsets of CD8+ T-cells with exercise is largely dependent on catecholamine signaling through the β₂-AR. These findings provide mechanistic insights by which distinct lymphocyte and monocyte subtypes are preferentially mobilized to protect the host from anticipated injury or infection in response to an acute stress response.

The Role of Beta-Blockers in the Treatment of Hypertension

IMPORTANCE

Two major guide-line committees (JNC-8 and NICE UK) have dropped beta-blockers as first-line therapy in the treatment of hypertension. Also, recent meta-analyses (that do not take age into account) have concluded that beta-blockers are inappropriate first-line agents in the treatment of hypertension. This review seeks to shed some light on the "rights and wrongs" of such actions and conclusions.

OBJECTIVES

Because the pathophysiology of primary/essential hypertension differs in elderly and younger subjects, the latter being closely linked to obesity and increased sympathetic nerve activity, the author sought to clarify the efficacy of beta-blockers in the younger/middle-aged group in reducing the risk of death, and cardiovascular end-points.

EVIDENCE ACQUISITION

Four searches were undertaken, utilising PubMed up to 31st Dec 2015. One search was under the terms "hypertension AND obesity AND sympathetic nerve activity". A second was "hypertension AND plasma noradrenaline/norepinephrine AND survival". A third was "beta-blockers or adrenergic beta-antagonists AND hypertension AND age AND stroke or myocardial infarction or death". A fourth was "meta-analysis of beta-blockers AND hypertension AND age AND death, stroke, myocardial infarction" RESULTS: Diastolic (with or without systolic) hypertension, in contrast to isolated systolic hypertension, occurs primarily in younger subjects, and is linked to overweight/obesity and increased sympathetic nerve activity. In younger/middle-aged hypertensive subjects, high plasma norepinephrine levels are linked (independent of blood pressure) to an increased risk of future cardiovascular events and death. High resting heart rates (a surrogate for high sympathetic nerve activity) likewise predict premature all-cause death, coronary heart disease and cardiovascular events in younger hypertensive subjects. In this younger/middle-aged hypertensive group, antihypertensive agents that increase sympathetic nerve activity (diuretics, dihydropyridine calcium blockers, and angiotensin receptor blockers (ARBs)) do not decrease (and may increase) the risk of myocardial infarction, and are therefore inappropriate first-line agents in this age-group. By contrast, in younger/middle-aged hypertensive subjects (less than 60 years old), meta-analysis has shown that beta-blockers are significantly superior to randomised placebo, and at least as effective as randomised comparator agents, in reducing death/stroke/myocardial infarction. In this younger/middle-aged hypertensive group beta-blockers have been shown (vs randomised placebo or diuretics) to reduce the risk of myocardial infarction by 35-50 %, and stroke by 50-55 % (vs placebo), in non-smoker men. Atenolol was at least as effective as ACE-inhibition (captopril) in reducing all 7 cardiovascular endpoints (including stroke which was reduced by 50 %), vs less tight control of blood pressure, in obese hypertensive subjects with type-2 diabetes (UKPDS study); and after 20 years follow-up, atenolol was significantly (23 %) superior to the ACE-inhibitor in reducing the risk of all-cause death (beta-blockers have anti-cancer properties, which maybe relevant).

CONCLUSIONS AND RELEVANCE

Primary/essential hypertension in younger/middle-age is underpinned by high sympathetic nerve activity. In this age-group high resting heart rates and high plasma norepinephrine levels (independent of blood pressure) are linked to premature cardiovascular events and death. Thus, anti-hypertensive agents that increase sympathetic nerve activity ie diuretics, dihydropyridine calcium blockers, and ARBs, are inappropriate first-line choices in this younger age-group. Beta-blockers perform well vs randomised placebo and other antihypertensive agents regarding reduced risk of death/stroke/myocardial infarction in younger (<60 years) hypertensive subjects, and are a reasonable first-line choice of therapy (certainly in men). These facts should be reflected in the recommendations of guideline committees around the world.

Exercise and the Regulation of Immune Functions

Exercise has a profound effect on the normal functioning of the immune system. It is generally accepted that prolonged periods of intensive exercise training can depress immunity, while regular moderate intensity exercise is beneficial. Single bouts of exercise evoke a striking leukocytosis and a redistribution of effector cells between the blood compartment and the lymphoid and peripheral tissues, a response that is mediated by increased hemodynamics and the release of catecholamines and glucocorticoids following the activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis. Single bouts of prolonged exercise may impair T-cell, NK-cell, and neutrophil function, alter the Type I and Type II cytokine balance, and blunt immune responses to primary and recall antigens in vivo. Elite athletes frequently report symptoms associated with upper respiratory tract infections (URTI) during periods of heavy training and competition that may be due to alterations in mucosal immunity, particularly reductions in secretory immunoglobulin A. In contrast, single bouts of moderate intensity exercise are "immuno-enhancing" and have been used to effectively increase vaccine responses in "at-risk" patients. Improvements in immunity due to regular exercise of moderate intensity may be due to reductions in inflammation, maintenance of thymic mass, alterations in the composition of "older" and "younger" immune cells, enhanced immunosurveillance, and/or the amelioration of psychological stress. Indeed, exercise is a powerful behavioral intervention that has the potential to improve immune and health outcomes in the elderly, the obese, and patients living with cancer and chronic viral infections such as HIV.

The effects of age and latent cytomegalovirus infection on the redeployment of CD8+ T cell subsets in response to acute exercise in humans

Dynamic exercise evokes a rapid redeployment of cytotoxic T cell subsets with high expression of β2 adrenergic receptors, presumably to enhance immunosurveillance during acute stress. As this response is affected by age and infection history, this study examined latent CMV infection as a potential confounder to age-related differences in blood CD8+ T-cell responses to exercise. Healthy young (n=16) and older (n=16) humans counterbalanced by CMV IgG serostatus (positive or negative) exercised for 30-min at ∼80% peak cycling power. Those with CMV redeployed ∼2-times more CD8+ T-cells and ∼6-times more KLRG1+/CD28- and CD45RA+/CCR7- CD8+ subsets than non-infected exercisers. Seronegative older exercisers had an impaired redeployment of total CD8+ T-cells, CD45RA+/CCR7+ and KLRG1-/CD28+ CD8+ subsets compared to young. Redeployed CD8+ T-cell numbers were similar between infected young and old. CMVpp65 specific CD8+ cells in HLA/A2(∗) subjects increased ∼2.7-fold after exercise, a response that was driven by the KLRG1+/CD28-/CD8+ subset. Stimulating PBMCs before and after exercise with CMVpp65 and CMV IE-1 antigens and overlapping peptide pools revealed a 2.1 and 4.4-fold increases in CMVpp65 and CMV IE-1 IFN-γ secreting cells respectively. The breadth of the T cell response was maintained after exercise with the magnitude of the response being amplified across the entire epitope repertoire. To conclude, latent CMV infection overrides age-related impairments in CD8+ T-cell redeployment with exercise. We also show for the first time that many T-cells redeployed with exercise are specific to CMVpp65 and CMV IE-1 antigens, have broad epitope specificity, and are mostly of a high-differentiated effector memory phenotype.

Pinpointing beta adrenergic receptor in ageing pathophysiology: victim or executioner? Evidence from crime scenes

G protein-coupled receptors (GPCRs) play a key role in cellular communication, allowing human cells to sense external cues or to talk each other through hormones or neurotransmitters. Research in this field has been recently awarded with the Nobel Prize in chemistry to Robert J. Lefkowitz and Brian K. Kobilka, for their pioneering work on beta adrenergic receptors (βARs), a prototype GPCR. Such receptors, and β2AR in particular, which is extensively distributed throughout the body, are involved in a number of pathophysiological processes. Moreover, a large amount of studies has demonstrated their participation in ageing process. Reciprocally, age-related changes in regulation of receptor responses have been observed in numerous tissues and include modifications of βAR responses. Impaired sympathetic nervous system function has been indeed evoked as at least a partial explanation for several modifications that occur with ageing. This article represents an updated presentation of the current knowledge in the field, summarizing in a systematic way the major findings of research on ageing in several organs and tissues (crime scenes) expressing βARs: heart, vessels, skeletal muscle, respiratory system, brain, immune system, pancreatic islets, liver, kidney and bone.

Age-related impairment in insulin release: the essential role of β(2)-adrenergic receptor

In this study, we investigated the significance of β(2)-adrenergic receptor (β(2)AR) in age-related impaired insulin secretion and glucose homeostasis. We characterized the metabolic phenotype of β(2)AR-null C57Bl/6N mice (β(2)AR(-/-)) by performing in vivo and ex vivo experiments. In vitro assays in cultured INS-1E β-cells were carried out in order to clarify the mechanism by which β(2)AR deficiency affects glucose metabolism. Adult β(2)AR(-/-) mice featured glucose intolerance, and pancreatic islets isolated from these animals displayed impaired glucose-induced insulin release, accompanied by reduced expression of peroxisome proliferator-activated receptor (PPAR)γ, pancreatic duodenal homeobox-1 (PDX-1), and GLUT2. Adenovirus-mediated gene transfer of human β(2)AR rescued these defects. Consistent effects were evoked in vitro both upon β(2)AR knockdown and pharmacologic treatment. Interestingly, with aging, wild-type (β(2)AR(+/+)) littermates developed impaired insulin secretion and glucose tolerance. Moreover, islets from 20-month-old β(2)AR(+/+) mice exhibited reduced density of β(2)AR compared with those from younger animals, paralleled by decreased levels of PPARγ, PDX-1, and GLUT2. Overexpression of β(2)AR in aged mice rescued glucose intolerance and insulin release both in vivo and ex vivo, restoring PPARγ/PDX-1/GLUT2 levels. Our data indicate that reduced β(2)AR expression contributes to the age-related decline of glucose tolerance in mice.

Diastolic dysfunction and heart failure with a preserved ejection fraction: Relevance in critical illness and anaesthesia

Epidemiological and clinical studies suggest that HF with a preserved ejection fraction will become the more common form of HF which clinicians will encounter. The spectrum of diastolic disease extends from the asymptomatic phase to fulminant cardiac failure. These patients are commonly encountered in operating rooms and critical care units. A clearer understanding of the underlying pathophysiology and clinical implications of HF with a preserved ejection fraction is fundamental to directing further research and to evaluate interventions. This review highlights the impact of diastolic dysfunction and HF with a preserved ejection fraction during the perioperative period and during critical illness.

Correlates of acute insulin resistance in the early phase of non-diabetic ST-elevation myocardial infarction

The relationship between insulin secretion and acute insulin resistance (as assessed by Homeostatic Model Assessment [HOMA] index) and clinical and biochemical parameters in the early phase of non-diabetic ST-elevation myocardial infarction (STEMI) is so far unexplored. We aimed at assessing this relation in 286 consecutive STEMI patients without previously known diabetes submitted to primary percutaneous coronary intervention (PCI). Insulin resistance (as indicated by HOMA) was detectable in 67.1%. Non-parametric correlation showed that HOMA index was significantly correlated with BMI (r = 0.242; p < 0.0001) and HbA(1c) (r = 0.189; p < 0.001). At multivariable backward linear regression analysis, glycaemia was directly related to leukocyte count (p = 0.0003), age (p = 0.0001), creatine kinase isoform MB (CK-MB) (p = 0.00278) and lactate (p < 0.0001). Insulin was directly and significantly related to glycaemia (p = 0.0006), body mass index (BMI) (p = 0.00028) and lactate (p = 0.0096) In the early phase of STEMI without previously known diabetes the acute glucose dysmetabolism is quite complex, comprising increased glucose values and the development of acute insulin resistance. While insulin secretion is strictly related to BMI, apart from glucose levels, increased glucose values can be mainly related to the acute inflammatory response (as indicated to leukocyte count and C-RP), to age and to the degree of myocardial damage (as inferred by CK-MB).

Acute glucose dysmetabolism in the early phase of ST-elevation myocardial infarction: the age response

In elderly patients with AMI, hyperglycaemia is associated with increased mortality. Recently it has been observed that insulin resistance, as assessed by the HOMA index, proved an independent predictor of in-hospital mortality. The interaction between age and glucose metabolism response in the acute phase of patients with STEMI without previously known diabetes has not yet been explored. We aimed to assess this relationship in 346 consecutive patients with STEMI admitted to our ICCU after primary PCI. When compared with the other age subgroups, the very oldest patients (aged > 79 years) showed the lowest LVEF (p=0.011), the highest incidence of 2- and 3-vessel coronary artery disease (p=0.002), and, finally, the highest mortality (p=0.037). Advancing age was associated with increased values of fibrinogen (p=0.022) and ESR (p=0.001), as well as of NT-pro-BNP (p<0.001). The very oldest patients (aged > 79 years) exhibited the highest values of glycaemia and peak glycaemia, while the incidence of insulin resistance (as inferred by HOMA index) remained unchanged across the age subgroups. This glycaemic pattern was confirmed after exclusion of patients with HbA(1c) > 6.5%, that is patients with a poor glycaemic control in the previous 2-3 months. In the acute phase of STEMI acute glucose metabolism is affected by age, since older patients showed the highest glucose levels and the poorest glycaemic control during ICCU stay despite the lack of differences in insulin resistance incidence.

A 5-year longitudinal study of the relationships between stress, coping, and immune cell beta(2)-adrenergic receptor sensitivity

Caring for a spouse with Alzheimer's disease (AD) is associated with overall health decline and impaired cardiovascular functioning. This morbidity may be related to the effects of caregiving stress and impaired coping on beta(2)-adrenergic receptors, which mediate hemodynamic and vascular responses and are important for peripheral blood mononuclear cell (PBMC) trafficking and cytokine production. This study investigated the longitudinal relationship between stress, personal mastery, and beta(2)-adrenergic receptor sensitivity assessed in vitro on PBMC. Over a 5-year study, 115 spousal AD caregivers completed annual assessments of caregiving stress, mastery, and PBMC beta(2)-adrenergic receptor sensitivity, as assessed by in vitro isoproterenol stimulation. Heightened caregiving stress was associated with significantly decreased receptor sensitivity, whereas greater sense of personal mastery was associated with significantly increased receptor sensitivity. These results suggest that increased stress may be associated with a desensitization of beta(2)-receptors, which may contribute to the development of illness among caregivers. However, increased mastery is associated with increased receptor sensitivity, and may therefore serve as a resource factor for improved health in this population.

Potential adverse effects of bronchodilators in the treatment of airways obstruction in older people: recommendations for prescribing

Asthma and chronic obstructive pulmonary disease (COPD) are common disorders that are associated with increasing morbidity and mortality in older people. Bronchodilators are used widely in patients with these conditions, but even when used in inhaled form can have systemic as well as local effects. Older people experience more adverse drug effects because of pharmacodynamic and pharmacokinetic changes and particularly drug-drug and drug-disease interactions. Cardiovascular disease is common in older people and beta-adrenoceptor agonists (beta-agonists) have inotropic and chronotropic effects that can increase arrhythmias and cardiomyopathy. They can also worsen or induce myocardial ischaemia and cause electrolyte disturbances that contribute to arrhythmias. Tremor is a well known distressing adverse effect of beta-agonist administration. Long-term beta-agonist use can be associated with tolerance, poor disease control, sudden life-threatening exacerbations and asthma-related deaths. Functional beta2-adrenoceptors are present in osteoblasts, and chronic use of beta-agonists has been implicated in osteoporosis. Inhaled anticholinergics are usually well tolerated but may cause dry mouth, which can be troublesome in older people. Pupillary dilatation, blurred vision and acute glaucoma can occur from escape of droplets from loosely fitting nebulizer masks. Although ECG changes have not been seen in randomized controlled trials of long-acting inhaled anticholinergics, supraventricular tachycardias have been observed in a 5-year randomized controlled trial of ipratropium bromide. Paradoxical bronchoconstriction can occur with inhaled anticholinergics as well as with beta-agonists, but tolerance has not been reported with anticholinergics. Anticholinergic drugs also cause central effects, most notably impairment of cognitive function, and these effects have been noted with inhaled agents. Use of theophylline is limited by its adverse effects, which range from commonly occurring gastrointestinal symptoms to palpitations, arrhythmias and reports of myocardial infarction. Seizures have been reported, but are rare. Theophylline is metabolized primarily by the liver, and commonly interacts with other medications. Its concentration in plasma should be monitored closely, especially in older people. Although many clinical trials have been conducted on bronchodilators in obstructive airways disease, the results of these clinical trials need to be interpreted with caution as older people are often under-represented and subjects with co-morbidities actively excluded from these trials.

Pharmacodynamics in older adults: a review

BACKGROUND

Older individuals experience physiologic changes in organ function related to aging or to specific disease processes. These changes can affect drug pharmacodynamics in older adults.

OBJECTIVE

The goal of this article was to review age-related changes in pharmacodynamics and their clinical relevance.

METHODS

PubMed and International Pharmaceutical Abstracts were searched (January 1980-June 2006) for the following combination of terms: pharmacodynamic and elderly, geriatric or aged. References cited in other reviews were also evaluated. The current review focused on age-related pharmacodynamic changes in agents affecting the central nervous system (CNS), cardiovascular, and endocrine functions.

RESULTS

Older adults frequently demonstrate an exaggerated response to CNS-active drugs. This is in part due to an underlying age-related decline in CNS function and in part due to increased pharmacodynamic sensitivity for some benzodiazepines, anesthetics, and opioids. The most important pharmacodynamic differences with age for cardiovascular agents are the decrease in effect for beta-adrenergic agents. This decline in response in vascular, cardiac, and pulmonary tissue may be due to a decrease in Gs protein interactions. Most studies indicate there is no decrease in cx-receptor sensitivity with age. Angiotensin-converting enzyme inhibitors do not show age-related differences in elderly patients. With the dihydropyridine calcium channel blockers, there was a slight increase in effect for older adults, but this was only for treatment-naive patients and was transient. Nondihydropyridines did not show an age- associated change in pharmacodynamic effect; however, in the elderly, there appeared to be a decrease in the PR interval prolongation normally seen with these agents. Studies of diuretics indicated that the changes in diuretic and natriuretic effects seen in the elderly were associated with pharmacokinetic changes and were not pharmacodynamic in nature. There was a lack of consistent evidence regarding whether sulfonylureas show age-related changes in pharmacodynamic effect.

CONCLUSIONS

There is a general trend of greater pharmacodynamic sensitivity in the elderly; however, this is not universal, and these age-related changes must be investigated agent-by-agent until further research yields greater understanding of the molecular mechanisms underlying the aging process.

Effect of aging on respiratory system physiology and immunology

With the looming expansion of the elderly population of the US, a thorough understanding of "normal" aging-related changes on the respiratory system is paramount. The respiratory system undergoes various anatomical, physiological and immunological changes with age. The structural changes include chest wall and thoracic spine deformities which impairs the total respiratory system compliance leading to increase work of breathing. The lung parenchyma loses its supporting structure causing dilation of air spaces: "senile emphysema". Respiratory muscle strength decreases with age and can impair effective cough, which is important for airway clearance. The lung matures by age 20-25 years, and thereafter aging is associated with progressive decline in lung function. The alveolar dead space increases with age, affecting arterial oxygen without impairing the carbon dioxide elimination. The airways receptors undergo functional changes with age and are less likely to respond to drugs used in younger counterparts to treat the same disorders. Older adults have decreased sensation of dyspnea and diminished ventilatory response to hypoxia and hypercapnia, making them more vulnerable to ventilatory failure during high demand states (ie, heart failure, pneumonia, etc) and possible poor outcomes.

[Evaluation of pulmonary function in the elderly. Intergroupe Pneumo Gériatrie SPLF-SFGG]

Aging is associated with a progressive decrease in lung function. As a consequence of aging, individual's reserve is diminished, but this decrease is heterogeneous between individual subjects. Many factors are involved in the overall decline in lung function. The prevalence of asthma in the elderly is estimated between 6 and 10%. Mortality due to COPD is increasing, especially among older subjects. Older subjects are at an increased risk of developing chronic diseases such as Parkinson's disease, which can have consequences for lung function. Under-nutrition is also common in the elderly and can produce sarcopenia and skeletal muscle dysfunction. The presentation of respiratory disorders may differ in the elderly, especially because of a lack of perception of symptoms such as dyspnea. The impact of bronchodilatators or corticosteroids on respiratory function has not been studied in the elderly. Drugs usually used for the treatment of hypertension or arrhythmias, which are often observed with aging, can have pulmonary toxicity. There is no difference between functional evaluation in younger and older subjects but it is more difficult to find predicted values for older patients. Performing pulmonary function tests in older patients is often difficult because of a higher prevalence of cognitive impairment and/or poor coordination. When assessing pulmonary function in the elderly, the choice of tests will be depend on the circumstances, with the use of voluntary manoeuvres dependent on the condition of the patient.

beta(2)-Adrenergic receptor-dependent sexual dimorphism for murine leukocyte migration

In wild-type FVB mice, leukocyte recruitment to lipopolysaccharide was sexually dimorphic, with a greater number of leukocytes recruited in females. In male beta(2)-adrenergic receptor knock out mice (bred on a congenic FVB background) the number of leukocytes recruited was increased approximately 4-fold, while in females there was no change, eliminating sexual dimorphism in leukocyte migration. While there were significantly fewer recruited CD62L(+) and CD11a(+) leukocytes in wild-type males, only in male beta-adrenergic receptor knock out mice was there an increase in the number of recruited CD11a(+) leukocytes, again eliminating sexual dimorphism. Thus, leukocyte migration and CD11a(+) adhesion molecule expression in male, but not in female, leukocytes is beta-adrenergic receptor-dependent. Our findings provide support for a role of beta(2)-adrenergic receptor mechanisms in the inflammatory response, and suggest that beta(2)-adrenergic receptor on male leukocytes contributes to sexual dimorphism in the effect of stress on inflammatory diseases.

Are we misunderstanding beta-blockers

In myocardial ischaemia and heart failure, beta-blockers with intrinsic sympathomimetic activity (ISA) e.g. pindolol, xamoterol, bucindolol, nebivolol, have performed poorly in reducing morbidity and mortality. In both indications beta-1 blockade is the vital active ingredient. Beta-1 blockade (bisoprolol) is now an alternative first-line choice to Ace-inhibition in the treatment of heart failure. The therapeutic role of beta-blockers in hypertension is less well understood, particularly since the new recommendations in the UK from the NICE committee stating that: 1. beta-blockers are no longer preferred as a routine initial therapy, 2. the combination with diuretics is discouraged due to the risk of induced diabetes, and 3. in younger patients first-choice initial therapy should be an ACE-inhibitor. Recent data from the Framingham Heart Study and other epidemiological studies have indicated that the development of diastolic hypertension in younger subjects is closely linked to weight-increase and an increase in peripheral resistance; such subjects have a high adrenergic drive and cardiac output. In contrast, elderly systolic hypertension mostly arises de novo via poor vascular compliance. Thus in younger, probably overweight, hypertensives (including diabetics) first-line beta-blockade has performed well in preventing myocardial infarction (a fact hidden by meta-analyses that do not take age into account). Conversely, in elderly hypertensives first-line beta-blockade (atenolol) has performed poorly in reducing cardiovascular risk (due to partial beta-2 blockade atenolol evokes metabolic disturbance and does not improve vascular compliance, or effectively lower central aortic pressure or reverse left ventricular hypertrophy). Thus beta-blockers like atenolol are ill-equipped for first-line therapy in elderly hypertension. Some beta-blockers, e.g. bisoprolol (up to 10 mg/day is highly beta-1 selective) and nebivolol (beta-2/3 intrinsic sympathomimetic activity), do improve vascular compliance and cause no metabolic disturbance. Beta-blockers as second-line to low-dose diuretics (which, by improving vascular compliance and increasing sympathetic nerve activity, create an optimal environment for beta-blockade) in elderly hypertension (including diabetics) have performed well in reducing cardiovascular events (this combination has the added bonus of reducing the risk of bone fracture by about 30%). Meta-analyses which include studies where it is unclear whether a diuretic or beta-blocker was a first-line therapy will dilute the benefit stemming from first-line diuretic/second-line beta-blockade. Hypertensives (of all ages) with ischaemia are well suited to beta-blockade.

Impact of Aging and .BETA.3-Adrenergic-Receptor Polymorphism on Thermic and Sympathetic Responses to a High-Fat Meal

The present study was designed to investigate the effect of aging and beta3-adrenergic-receptor (beta3-AR) polymorphism on the thermic effect of meal (TEM) and sympathetic nervous system (SNS) response to a high-fat meal in 13 boys, 12 young men, and 11 middle-aged men. SNS activity was assessed via power spectral analysis of heart rate variability. Significantly higher very-low-frequency (VLF) components associated with thermogenic SNS activity and energy expenditure per lean body mass (EE(LBM)) were observed in boys during the pre- and postprandial periods. There were no significant differences in VLF and EE(LBM) in the preprandial period between the young and middle-aged men. After feeding, however, the middle-aged men showed a significantly lower TEM (% test-meal energy) and VLF compared to the young men. A multiple regression analysis revealed that age was the only significant variable contributing to both TEM and VLF, but beta3-AR polymorphism and percentage of body fat were not statistically significant. In conclusion, age likely has a greater influence on TEM and SNS thermoregulation than genetic factors such as beta3-AR polymorphism, suggesting that this age-related decrease in thermogenic response may be involved in the development of obesity among middle-aged men.

The use of bronchodilators in the treatment of airway obstruction in elderly patients

Ageing is associated with important anatomical, physiological and psychosocial changes that may have an impact on the management of obstructive airway diseases (asthma and chronic obstructive pulmonary disease (COPD)) and on their optimal therapy. Ageing-related modifications might be responsible for a different effectiveness of bronchodilators in the elderly patients as compared to younger subjects. Furthermore, the physiological involution of organs and the frequent comorbidity, often interfere with pharmacokinetics of bronchodilator drugs used in asthma and COPD. This review will focus on the use of bronchodilators in the elderly, with particular attention to the achievable goals and to rationale, utility and pitfalls in using the inhalation therapy in this age group. beta(2)-agonists, anticholinergics and methylxanthines will be discussed and their side effects in the elderly will be considered.

Aging and cardiovascular reactivity to stress: longitudinal evidence for changes in stress reactivity

Although age differences in cardiovascular function are well documented, little research has provided longitudinal evidence for age-related changes in cardiovascular reactivity to stress. In this study, the authors report such data from a follow-up of their prior work (B. N. Uchino, D. Uno, J. Holt-Lunstad, & J. B. Flinders, 1999) with participants between the ages of 30 to 70 (n=108, mean follow-up=10 months, range=7 to 16 months). Results revealed longitudinal evidence for an age-related increase in systolic blood-pressure reactivity and parasympathetic withdrawal to acute stress. The implications of these findings are discussed in light of the increased cardiovascular disease risk with age, as well as the links between aging, emotions, and physiology.

Aging does not affect beta-agonist responsiveness after methacholine-induced bronchoconstriction

OBJECTIVES

To assess the response to an inhaled beta-agonist alone or in combination with an anticholinergic agent after methacholine-induced bronchoconstriction in four age groups.

DESIGN

Retrospective analysis.

SETTING

Pulmonary function laboratory in a university-affiliated hospital.

PARTICIPANTS

Seven hundred sixty-four consecutive subjects with a 20% reduction or more in forced expiratory volume during the first second (FEV1) of exhalation from total lung capacity after inhaling 189 or fewer cumulative units of methacholine were included in the analysis.

INTERVENTION

The first 382 subjects received three inhalations of metaproterenol (total of 1.95 mg), and the other 382 subjects received three inhalations of albuterol and ipratropium combination (total of 309 microg of albuterol and 54 microg of ipratropium) after methacholine-induced bronchoconstriction.

MEASUREMENTS

The response to bronchodilators was assessed as the postbronchodilator percentage change in FEV1 and the percentage of subjects recovering to 90% or better of baseline FEV1 after the use of bronchodilator.

RESULTS

The percentage change in FEV1 postbronchodilator in the elderly was similar to that of the younger subjects. The percentage of subjects who recovered to 90% or better of their baseline FEV1 postbronchodilator was also similar in the elderly and younger age groups. Response to metaproterenol was similar to that of the albuterol/ipratropium combination in all age groups (all P>.05).

CONCLUSION

Aging does not affect bronchodilator response to beta-agonist after methacholine-induced bronchoconstriction. The responsiveness to beta-agonist alone is similar to the responsiveness to the combination of beta-agonist and anticholinergic agent in all age groups.

Renal, but not systemic, hemodynamic effects of dopamine are influenced by the severity of congestive heart failure

OBJECTIVE

To determine whether the short-term systemic and renal hemodynamic response to dopamine is influenced by clinical severity of congestive heart failure.

DESIGN

Effects of increasing doses of dopamine were assessed in patients consecutively admitted for acutely decompensated congestive heart failure.

SETTING

Intensive care unit.

PATIENTS

We enrolled 16 congestive heart failure patients stratified by clinical severity (New York Heart Association [NYHA] class III, n = 8; NYHA class IV, n = 8) and two additional NYHA class III patients as controls.

INTERVENTIONS

Measurements were carried out throughout five 20-min experimental periods: baseline, dopamine infusion at 2, 4, and 6 microg x kg(-1) x min(-1), and recovery. Controls received a similar amount of saline.

MEASUREMENTS AND MAIN RESULTS

Systemic and renal hemodynamics were determined respectively by right cardiac catheterization and radioisotopes (iodine 131-labeled hippuran and iodine 125-labeled iothalamate clearance). The peak increase in heart rate and cardiac index occurred at a dopamine dose of 4-6 microg x kg(-1) x min(-1). The dose-response relation was similar in NYHA classes III and IV. Improvement in effective renal plasma flow and glomerular filtration rate, peaking at 4 microg x kg(-1) x min(-1), was more rapid and marked in NYHA class III than class IV patients, in whom the renal fraction of cardiac output failed to increase. The systemic and renal effects of dopamine were independent of age. No change occurred in controls.

CONCLUSIONS

The dose of dopamine producing an optimal improvement of systemic and renal hemodynamics in congestive heart failure is higher than usually reported. A greater clinical severity of congestive heart failure impairs the renal effects of dopamine, probably through a selective loss in renal vasodilating capacity.

beta-Blockers in hypertension: is carvedilol different?

Most studies assessing the effects of beta-blockers were carried out with traditional, beta(1)-selective beta-blockers, such as metoprolol and atenolol. Pathophysiologic and pharmacologic studies have documented that not all beta-blockers are created equal. In particular, the pharmacologic and clinical profiles of the newer, vasodilating beta-blockers, such as carvedilol, have been shown to differ from those of the traditional beta-blockers. These differences, although relevant in the younger patient with hypertension, are particularly important in elderly patients in whom traditional beta-blockers may not be as effective or as well tolerated as the newer vasodilating agents.

Cardiovascular drug therapy in the elderly: theoretical and practical considerations

The elderly population is expanding rapidly throughout the world. Hypertension, heart disease and other cardiovascular disorders are prevalent conditions among this age group. Consequently, clinicians will spend a large proportion of their practices managing older adults with cardiovascular disorders. A large proportion of this time will be devoted to using pharmacotherapeutic strategies for the long-term management of chronic conditions. The physiological changes that accompany aging affect cardiovascular function, and the pharmacokinetics and pharmacodynamics of many cardiovascular medications are altered by these physiological changes. The interactions of these changes can have a profound effect on the agents used to treat cardiovascular disorders and may alter their therapeutic outcomes. Several classes of medications are used to treat chronic cardiovascular disorders in older adults. These include the ACE inhibitors and angiotensin II receptor antagonists, calcium channel antagonists, beta-adrenoceptor antagonists (beta-blockers), oral antiarrhythmic agents and warfarin. Drugs such as beta-blockers may aggravate decreased cardiac output and increase peripheral resistance, but are valuable adjuncts in many patients with congestive heart failure. Agents that reduce angiotensin II activity may have several benefits for treating heart failure and hypertension. Successful treatment of cardiovascular disorders in older adults requires the choice of the most appropriate agent, taking into consideration the complex interactions of pharmacokinetics, pharmacodynamics and disease effects.

Pathophysiological changes in the elderly

Demographic data indicate an increasing workload of geriatric anaesthesia due to advancing life expectancy and reduced thresholds for high-invasive and high-risk surgery in the elderly. Chronological and biological age may be inconsistent, and the existence of age-related changes may vary between organ systems in the same individual. Age itself is not an illness, but is the most important contributing factor for perioperative complications and adverse outcome when the overall narrowed margins of organ function reserve are transgressed during the perioperative period. Age-related changes in the cardiovascular, pulmonary, nervous, metabolic and locomotive systems that are frequently present in the elderly are discussed with regard to their potential relevance to anaesthesiology. In conclusion, listing current diagnoses will not be sufficient in the assessment of the geriatric patient because age-related changes do not necessarily manifest as pathological entities. Rather, pre-operative examination should focus on determination of individual margins of organ function reserve.

Why beta-blockers are not cardioprotective in elderly patients with hypertension

Despite the fact that beta-blockers have been used for the treatment of hypertension for more than 30 years, no study has shown that their use reduces morbidity and mortality in the elderly. To the contrary, the British Medical Research Council trial in the elderly documented that although blood pressure was lowered effectively and significantly by atenolol, morbidity and mortality in the beta-blocker group did not differ from that of the placebo group. Not only was beta-blocker monotherapy not effective, but patients who received the combination of beta-blockers and diuretics fared consistently worse than those on diuretics alone. beta-blockers are less effective than diuretics in lowering blood pressure, and are poorly tolerated in the elderly. The reason for their inefficacy in the elderly may be related to their inherent unfavorable effect on systemic hemodynamics and pathophysiologic findings in the arterial tree, heart, kidneys, brain, and on the metabolism of lipids and carbohydrates. Decreased beta-adrenergic responsiveness with age and comorbid conditions makes beta-blockers unattractive. Thus, they should not be considered appropriate for first-line therapy of uncomplicated hypertension in the geriatric population.

Adrenergically stimulated fat utilization and ageing

Ageing is associated with a diminished ability to use fat as a fuel during exercise. Also, middle-aged subjects have a blunted ability to mobilize fatty acids and to increase skeletal muscle fatty acid uptake and oxidation during intravenous beta-adrenergic stimulation, indicating that the sympathetic nervous system may play a role in the disturbed fat utilization. The blunted lipolytic response may be related to disturbances at the receptor level, eg a diminished number or agonist affinity of beta-adrenoceptors, or at the postreceptor level, eg a diminished activity of the hormone-sensitive lipase complex. As the rates of fatty acid availability are not limiting during exercise or beta-adrenergic stimulation in the elderly, the lowered skeletal muscle fat oxidation is probably related to an age-related decline in the capacity of skeletal muscle to oxidize fatty acids. Factors responsible for this decline may be a diminished content of oxidative enzymes, an increased glycolytic flux inhibiting fatty acid transport into the mitochondria, or a diminished (possibly beta-adrenergically-mediated) activation of fatty acid transport. It remains to be determined to what extent disturbances of fat metabolism may be related to the ageing process per se or whether they are secondary to age-related changes in body fat distribution and level of physical activity. Nevertheless, the impairments in sympathetically mediated lipolysis and fat oxidation may be of importance in the age-related increase in adiposity and insulin resistance and may thus be one of the links between ageing and increased prevalence of chronic diseases, such as obesity, type 2 diabetes mellitus, and cardiovascular disease.

Aging reduces the efficacy of the simulated epidural test dose in anesthetized adults

Aging is associated with reduced beta-adrenergic responsiveness. However, the age-related effects on hemodynamic changes and effectiveness of a simulated epidural IV test dose have not been defined during general anesthesia. We studied 20 (140 total) consecutive patients (ASA physical status I) assigned in each of the following age groups after endotracheal intubation and during stable end-tidal sevoflurane 2% and 67% nitrous oxide anesthesia (in yr): 10s, 20s, 30s, 40s, 50s, 60s, and 70s. Each group first received normal saline 3 mL IV, followed 4 min later by 1.5% lidocaine 3 mL plus 15 microg epinephrine (1:200,000) IV for 5 s. Heart rate (HR) and systolic blood pressure (SBP) were continuously monitored for 4 min after saline administration and the test dose injections. None receiving IV saline and all patients receiving IV test dose in age groups 10s to 50s developed HR increases > or = 10 bpm, whereas 17 and 13 patients met this HR criterion in age groups 60s and 70s (85% and 65% sensitivities), respectively. There was a significant inverse correlation between the maximum HR increase and the age (P: < 0.001 by Spearman's rank correlation). However, none receiving saline and all patients receiving IV test dose in all age groups developed SBP increases of 15 mm Hg, resulting in 100% efficacy based on the SBP criterion. We conclude that during stable sevoflurane anesthesia administration (a) the efficacy based on the HR criterion for detecting accidental intravascular injection of the epidural test dose is age-dependent, (b) the HR criterion may be clinically applicable only in patients <60 yr of age, and (c) the SBP criterion is effective for all age groups studied.

IMPLICATIONS

To determine whether an epidurally administered local anesthetic has been unintentionally injected into a blood vessel, a small dose of epinephrine is often added to a local anesthetic. We found that an increase in systolic blood pressure > or = 15 mm Hg is a more useful indicator than an increase in heart rate > or = 10 bpm in the patients > or = 60 yr old during stable sevoflurane anesthesia administration.

Impaired isoproterenol-induced hyperpolarization in isolated mesenteric arteries of aged rats

Stimulation of vascular beta-adrenoceptors leads to membrane hyperpolarization, presumably via the beta-adrenoceptor/G(s) protein/adenylate cyclase signaling cascade; the ionic mechanisms of this phenomenon remain unclear. beta-Adrenoceptor-mediated vascular relaxation is impaired with aging; however, little is known concerning whether beta-adrenoceptor-mediated hyperpolarization is altered with aging. We sought to determine the ionic mechanisms of isoproterenol-induced hyperpolarization in the rat mesenteric resistance artery, as well as the age-related changes in isoproterenol-induced hyperpolarization and their underlying mechanisms. Isoproterenol-induced hyperpolarization was inhibited by high-K(+) solution and glibenclamide (10(-6) mol/L), an inhibitor of ATP-sensitive K(+) channels (K(ATP)), but not by apamin, iberiotoxin, or charybdotoxin, inhibitors of Ca(2+)-activated K(+) channels. Isoproterenol-induced hyperpolarization was markedly less in aged rats (>/=24 months) than in adults rats (12 to 20 weeks) (3x10(-6) mol/L; -3.1 versus -9.9 mV; P<0.001; n=8 to 9). Cholera toxin (10(-9) g/mL), an activator of G(s), evoked hyperpolarization only in adult rats. Hyperpolarization to forskolin, a direct activator of adenylate cyclase, was also reduced to some extent in aged rats (10(-5) mol/L; -8.8 versus -13 mV; P<0.05; n=6), whereas hyperpolarization to levcromakalim, a K(ATP) opener, was comparable in both groups. These findings suggest that isoproterenol elicits hyperpolarization via an opening of K(ATP) in the rat resistance artery and that isoproterenol-induced hyperpolarization is attenuated in aged rats mainly because of a defective coupling of beta-adrenoceptors to adenylate cyclase and partly because of a defect at the level of adenylate cyclase, but not because of an alteration of K(ATP) per se.

The effects of age on human venous responsiveness to neuropeptide Y

AIMS

Neuropeptide Y (NPY) is a sympathetic neurotransmitter released with noradrenaline during sympathetic stimulation. Ageing has been shown to be associated with a reduction in alpha2 and beta-adrenoceptor mediated responses in veins, but it is not known whether NPY responsiveness is also altered with increasing age.

METHODS

Using a dorsal hand vein technique, we examined NPY receptor responsiveness in 24 normal, healthy subjects (20-72 years; 10 males, 14 females). Graded infusions of NPY (25-2000 pmol min(-1)) were administered (5 min at each dose) into a dorsal hand vein. Venous distension at 45 mmHg was measured at 3-5 min of each infusion. Dose-response curves to NPY were constructed and the peak venoconstriction was calculated.

RESULTS

Dose-dependent venoconstriction was seen in all but one subject. The peak venoconstriction observed with NPY was significantly and negatively correlated with the age of the normal subjects (r=-0.63, P<0.01). When subjects were ranked from youngest to oldest and divided into tertiles, (20-40 years, n = 8; 41-55 years, n = 8; 56-72 years, n = 8), mean dose-response curves were different with the oldest tertile being significantly less responsive (P<0.05). The peak venoconstriction observed (% of control) was 65.1+/-7.0, 46.5+/-9.4, and 24.4+/-4.8%, respectively. The oldest tertile had a significantly decreased peak venoconstriction compared with the youngest tertile (P<0.01). Infusion of NPY into a dorsal hand vein had no systemic effects on heart rate or blood pressure in any of the subjects studied.

CONCLUSIONS

Hand vein responsiveness to exogenously infused NPY in normal subjects is decreased as age increases. The reduction of NPY-receptor-mediated responses with age may influence sympathetic nervous system control of the venous system with advancing age.

Effect of age upon airway obstruction and reversibility in adult patients with asthma

OBJECTIVE

In a cross-sectional study we evaluated the effect of aging (separately from that of duration of disease) on airway obstruction and reversibility by comparing two groups of non-smoker patients with asthma.

METHODS

We compared two groups of patients: group A, which had 50 subjects (8 men and 42 women) aged 59.7+/-4.6 years (mean +/- SD), and group B, comprised of 51 subjects (19 men and 32 women) who were 35.7+/-7.4 years old. The groups were selected because of comparable baseline degree of obstruction (FEV1 % of predicted, 67.8+/-20.3 in group A; 73.0+/-19.6 in group B, NS) and duration of the disease (14.0+/-11.7 years vs 11.2+/-9.1, NS). Spirometric examination, with a bronchodilator test, was performed and subjects not reaching 85% of predicted were submitted to a 4-week course of inhaled steroids.

RESULTS

Although a higher number of subjects from group B responded to the acute bronchodilator test (p < 0.001), the maximum response achievable with treatment (steroid or bronchodilator) (deltaFEV1 expressed as the percent of predicted) was not statistically different between groups (12.0+/-17.5 vs 16.0+/-23.9). The mean FEV1 attainable after treatment (deltaFEV1%PT) was significantly lower in the older group (p = 0.0006). Within groups, the baseline FEV1% did not correlate with age; it was inversely correlated with the duration of the disease (p < 0.03 and p < 0.01, respectively). In both groups deltaFEV1 was inversely related with the baseline FEV1, whereas FEV1%PT was correlated with the duration of the disease, with a slope nearly doubled in group B (p < 0.001).

CONCLUSIONS

Both the process of aging and the prolonged exposure to disease effects are important factors in determining the functional characteristics of chronic asthma: In particular, aging is associated not only with a reduced acute responsiveness to bronchodilators, but also with a reduced slope of the duration-FEV1%PT relationship that suggests a slowing of the rate of loss of reversibility of uncertain biological meaning.

Pharmacokinetic and pharmacodynamic changes in the elderly. Clinical implications

Age-related changes in pharmacokinetics principally affect drug absorption, distribution, metabolism and elimination. Changes in pharmacodynamics are primarily seen in the cardiovascular and neuroendocrine system. Age-dependent changes in the kinetics and dynamics of drugs acting on the cardiovascular system and central nervous system are common, and this review, while by no means exhaustive of the effects of drugs on all organ systems, is reflective of the principles and gives examples of the effects of age on these 2 major systems. While pharmacokinetic changes in the elderly are usually well characterised, pharmacodynamic changes are understood only in the most preliminary way. There has been relatively little research in this area of geriatric clinical pharmacology, and pharmacodynamic changes are still an area of investigation.

Effect of aging on beta-adrenergically mediated thermogenesis in men

The age-dependent alterations in beta-adrenergically mediated thermogenesis were investigated in 11 young (mean +/- SE age: 21.9 +/- 0.5 yr) and 9 older (52.9 +/- 2.1 yr) men during intravenous infusion of the nonselective beta-agonist isoprenaline (Iso). The older men had higher basal plasma norepinephrine (327.7 +/- 35.8 vs. 159.0 +/- 18.2 pg/ml, P < 0.001) and epinephrine (75.1 +/- 18.1 vs. 29.1 +/- 5.3 pg/ml, P < 0.05) concentrations than the young. The beta-adrenergically mediated thermogenesis was diminished in the older men, as reflected by the significantly higher plasma Iso concentration needed to increase resting energy expenditure by 15% (236.1 +/- 51.0 vs. 107.6 +/- 11.4 pg/ml, P < 0.05). Additionally, both dose (39.4 +/- 6.6 vs. 19.1 +/- 1.5 ng . kg fat-free mass-1 . min-1, P < 0.01) and plasma concentration (332.2 +/- 59.1 vs. 119.3 +/- 14.0 pg/ml, P < 0.01) of Iso needed to increase resting heart rate by 25 beats/min were higher in older than in younger subjects, suggesting that the age-related decline in beta-adrenergic sensitivity is a generalized defect not related to a specific tissue or response. In conclusion, aging is associated with a diminished beta-adrenergically mediated thermogenesis. This blunted thermogenic response may contribute to a positive energy balance and thus promote increased fat storage and obesity.

Alterations in myocardial signal transduction due to aging and chronic dynamic exercise

Normal aging without disease leads to diminished chronotropic and inotropic responses to catecholamine stimulation, resulting in depressed cardiac function with stress. The purpose of this study was to determine molecular mechanisms for decrements in adrenergic responsiveness of the left ventricle (LV) due to aging and to study the effects of chronic dynamic exercise on signal transduction. We measured beta-adrenergic receptor (beta-AR) density, adenylyl cyclase (AC) activity, and G-protein content and distribution in LV from 66 male Fischer 344 rats from three age groups that were either sedentary or treadmill trained (60 min/days, 5 days/wk, 10 wk at 75% of the maximal capacity). Final ages were 7 mo (young), 15 mo (middle-age), and 25 mo (old). There was no significant difference in beta-AR density among groups as a function of age or training. AC production of adenosine 3',5'-cyclic monophosphate (cAMP) with the use of five pharmacological stimulations revealed that old sedentary myocardium had depressed basal, receptor-dependent, G-protein-dependent, and AC catalyst stimulation (30-43%) compared with hearts from young and middle-age sedentary rats. Training did not alter AC activity in either middle-age or old groups but did increase G-protein-dependent cAMP production in young myocardium (12-34%). Immunodetectable concentrations of stimulatory and inhibitory G proteins (Gs and Gi, respectively) showed 43% less total Gs with similar Gi content in hearts from old sedentary compared with middle-age sedentary rats. When compared with young sedentary animals, Gi content was 39 and 50% higher in middle-age sedentary and old sedentary myocardium, respectively. With age, there was a significant shift in the alpha-subunit of Gs distribution from cytosolic fractions of LV homogenates to membrane-bound fractions (8-12% redistribution in middle-age sedentary vs. old sedentary). The most significant training effect was a decrease in Gi content in hearts from old trained rats (23%), which resulted in values comparable with young sedentary rats and reduced the Gi/Gs ratio by 27% in old-rat LV. We report that age-associated reductions in cardiovascular beta-adrenergic responsiveness correspond with alterations in postreceptor adrenergic signaling rather than with a decrease in receptor number. Chronic dynamic exercise partially attenuates these reductions through alterations in postreceptor elements of cardiac signal transduction.

Abnormal passive head-up tilt test in subjects with symptoms of anxiety power spectral analysis study of heart rate and blood pressure

Previous reports that subjects with anxiety symptoms are at higher risk of sudden death may imply that anxiety induces stable sympathetic hyperactivity. To address this subject, in persons with and without anxiety symptoms, we evaluated autonomic nervous system activity by power spectral analysis of heart-rate and arterial-pressure variability at baseline (rest) and after sympathetic stress (tilt). The 117 subjects selected (56 men and 61 women, age range 23-87 years) were subdivided by questionnaire into three groups: 49 subjects (mean age 55.8+/-2.8 years) had no anxiety symptoms; 36 (mean age 56.8+/-3.6 years) had one anxiety symptom; and 32 (mean age 55.0+/-2.9 years) had two or more anxiety symptoms. Power spectral analysis recognizes three main components: high frequency (HF), chiefly reflecting vagal efferent activity; low frequency (LF), reflecting sympathetic activity; and very-low-frequency (VLF). The ratio of low- to high-frequency powers (LF:HF) of heart rate variability provides a measure of sympathovagal balance. Power spectral analysis showed that subjects with two or more anxiety symptoms had significantly lower resting values for all power spectral components of heart rate variability: total power (TP), VLF, LF, and HF than did symptomless controls (P<0.05). The highest anxiety-score groups also had a higher baseline LF:HF than the other two groups (P<0.05). Their resting LF:HF ratio correlated positively with anxiety symptom scores (r=0.72, P<0.0001). Tilt induced opposite results: the highest anxiety-score groups had a significantly lower LF:HF ratio; the ratio correlated inversely with their anxiety scores (r=-0.69; P<0.0001). Recordings of resting systolic arterial pressure variability showed that the group with two or more anxiety symptoms had significantly higher LF power (P<0.05) than symptomless controls. Our findings suggest that persons with high anxiety scores have baseline cardiac sympathetic hyperactivity. They also have low heart-rate variability, possibly explaining their susceptibility to sudden cardiac death.

Plasma catecholamine and lymphocyte beta 2-adrenergic receptor alterations in elderly Alzheimer caregivers under stress

OBJECTIVE

The purpose of this study was to determine the effects of chronic stress on beta-adrenergic physiology in elderly spousal caregivers to Alzheimer patients.

METHODS

Thirty-seven elderly spousal caregivers and matched noncaregiver controls (mean age 73 years, SD = 6) were studied. Life stress categorization (presence of marked threat) covering the previous 6 months was determined using a semistructured interview based on the Psychiatric Epidemiological Research Inventory and the Life Events and Difficulties Schedule. beta 2-adrenergic receptor sensitivity (isoproterenol-stimulated cyclic AMP accumulation) and density were determined in lymphocytes.

RESULTS

Caregivers with high life stress had higher plasma norepinephrine levels (p < .04) but no change in plasma cortisol. For beta-receptor sensitivity, 30% of the variance was accounted for by high life stress rating, increased age, being male, and lower norepinephrine (p = .018); 17% of the variance in beta-receptor density was accounted for by plasma norepinephrine (p = .03).

CONCLUSIONS

The findings demonstrate that chronic high stress may be associated with changes in adrenergic physiology and may provide a mechanism through which chronic stress alters cellular immunity.

Regulation of beta 2-adrenergic receptors on mononuclear leukocytes in patients with acute ischemic heart disease

OBJECTIVE

To investigate relationships between acute adrenergic stress, plasma catecholamine concentrations, and beta 2-adrenergic receptors.

DESIGN

Prospective, descriptive study.

SETTING

Emergency medical service at a university hospital.

PATIENTS

Twenty-seven patients with out-of-hospital cardiac arrest (n = 11), myocardial infarction (n = 6), and angina pectoris (n = 10), and 12 control subjects.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Mononuclear leukocyte beta 2-adrenergic receptor density and affinity were measured in patients 15 mins after successful cardiopulmonary resuscitation and after the diagnosis of myocardial infarction or angina pectoris, respectively, and were measured as well in control subjects. Plasma concentrations of catecholamines, glucose, and lactate were simultaneously measured with heart rate and blood pressure. After cardiac arrest, the density of beta 2-adrenergic receptors (1858 +/- 188 sites/cell [p < .01]), plasma epinephrine concentration (31,990 +/- 14,526 pg/mL [174.6 +/- 79.3 nmol/L] [p < .01]), heart rate (100 +/- 6 beats/min [p < .01]), glucose concentration (14.9 +/- 0.8 mmol/L [p < .01]), and lactate concentration (10.9 +/- 0.6 mmol/L [p < .01]) were increased in patients compared with those values in healthy controls.

CONCLUSION

Acute maximal stress, such as after cardiac arrest, is associated with an increase in the density of beta 2-adrenergic receptors on mononuclear leukocytes derived from patients after successful cardiopulmonary resuscitation.