Congestive heart failure: where homeostasis begets dyshomeostasis

Risk Factors Associated With Lower Bone Mineral Density in Primary Aldosteronism Patients

PURPOSE

The association between primary aldosteronism (PA) and lower bone mineral density (BMD) has raised a concern, but the contributing factors remain unclear. We aim to explore the risk factors for lower BMD in PA patients.

METHODS

We analyzed and compared the data of 60 PA patients with 60 matched essential hypertension (EH) patients. BMD, bone metabolites, and several oxidative stress and inflammation indicators-including C-reactive protein (CRP), superoxide dismutase (SOD), total bilirubin (TBIL), mean platelet volume (MPV), etc.-were assessed and compared in PA and EH patients. Bivariate correlation analysis and multivariate linear regression analysis were performed to explore the factors associated with BMD in PA patients.

RESULTS

The BMD measured by quantitative computed tomography in PA patients was lower than that in EH patients (141.9 ± 34.0 vs. 158.9 ± 55.9 g/cm³, p = 0.047), especially in patients less than 50 years old. BMD was independently negatively associated with age (standardized β = -0.581, p < 0.001), serum phosphorus (standardized β = -0.203, p = 0.008), urinary calcium excretion (standardized β = -0.185, p = 0.031), and MPV (standardized β = -0.172, p = 0.043) and positively associated with SOD (standardized β = 0.205, p = 0.011) and TBIL (standardized β = 0.212, p = 0.015).

CONCLUSIONS

The PA patients showed a lower BMD than the EH patients, which was associated with age, serum phosphorus, urinary calcium excretion, MPV, SOD, and TBIL. These variables might be potential markers for the assessment of bone loss and efficacy of treatments in PA patients.

Real-world impact of glucocorticoid replacement therapy on bone mineral density: retrospective experience of a large single-center CAH cohort spanning 24 years

The congenital adrenal hyperplasia population seems to have an intrinsic tendency to a high frequency of low bone mass. However in this single-center and long-term evaluated cohort, the simplified corticoid regimen, with exclusive dexamethasone single dose reposition during adulthood, did not represent a risk factor for decrease in bone health.

INTRODUCTION

The impact of long-term and supposedly physiological doses of gluco and mineralocorticoid (GC/MC) on bone mineral density (BMD) in congenital adrenal hyperplasia (CAH) remains discordant among studies, which contain different clinical forms and corticoid regimens. Our aim was to evaluate the BMD in CAH adults receiving similar GC regimen since childhood and to correlate it with GC/MC cumulative doses.

METHODS

Only patients with good compliance, who used cortisone acetate (CA) during childhood and dexamethasone after the final height achievement. Cumulative GC/MC doses were calculated from diagnosis until last evaluation. BMD was analyzed by the first and last energy X-ray absorptiometry (DXA) scans performed.

RESULTS

Twenty simple virilizing (SV) and 14 salt wasting (WS) whose mean age was 26 ± 6 years, mean CA, dexamethasone, and fludrocortisone cumulative doses were 63,813 ± 32,767, 812 ± 558, and 319 ± 325 mg/m², respectively. Based on the last DXA, low BMD was observed in 11% of patients, total hip Z-score was lower in the SW than SV form (p = 0.04). Cumulative CA dose had an inverse correlation with femoral neck Z-score (p < 0.01). Total cumulative GC and MC doses had an inverse correlation with total hip Z-score (p < 0.01). In the analysis of sequential BMD during dexamethasone therapy, no association was observed among cumulative GC/MC doses, clinical forms, sex, and lumbar Z-score delta.

CONCLUSIONS

Even though a low CA regimen during growth periods in addition to MC replacement appears to have an influence on BMD at femoral sites, interestingly a low dexamethasone one does not seem to be deleterious for bone health in adulthood.

iTRAQ‑based quantitative proteomics analysis of the potential application of secretoneurin gene therapy for cardiac hypertrophy induced by DL‑isoproterenol hydrochloride in mice

A previous study by our group demonstrated a protective role of the neuropeptide secretoneurin (SN) in DL‑isoproterenol hydrochloride (ISO)‑induced cardiac hypertrophy in mice. To further characterize the molecular mechanism of SN treatment, an isobaric tags for relative and absolute quantification (iTRAQ)‑based quantitative proteomic analysis was applied to identify putative target proteins and molecular pathways. An SN expression vector was injected into the myocardial tissues of mice, and the animals were then subcutaneously injected with ISO (5 mg/kg/day) for 7 days to induce cardiac hypertrophy. The results of echocardiography and hemodynamic measurements indicated that the function of the heart impaired by ISO treatment was significantly ameliorated via SN gene injection. The investigation of heart proteomics was performed by iTRAQ‑based liquid chromatography‑tandem mass spectrometry analysis. A total of 2,044 quantified proteins and 15 differentially expressed proteins were associated with SN overexpression in mice with cardiac hypertrophy. Functional enrichment analysis demonstrated that these effects were possibly associated with metabolic processes. A protein‑protein interaction network analysis was constructed and the data indicated that apolipoprotein C‑III (Apoc3) was associated with the positive effect of SN on the induction of cardiac hypertrophy in mice. The present study proposed a potential mechanism of SN action on Apoc3 upregulation that may contribute to the amelioration of cardiac hypertrophy. These findings can aid the clinical application of SN in patients with cardiac hypertrophy.

Adrenocortical incidentalomas and bone: from molecular insights to clinical perspectives

Adrenal incidentalomas constitute a common clinical problem with an overall prevalence of around 2-3%, but are more common with advancing age being present in 10% of those aged 70 years. The majority of these lesions are benign adrenocortical adenomas (80%), characterized in 10-40% of the cases by autonomous cortisol hypersecretion, and in 1-10% by aldosterone hypersecretion. Several observational studies have shown that autonomous cortisol and aldosterone hypersecretion are more prevalent than expected in patients with osteopenia and osteoporosis: these patients have accelerated bone loss and an increased incidence of vertebral fractures. In contrast to glucocorticoid action, the effects of aldosterone on bone are less well understood. Recent data, demonstrating a concomitant co-secretion of glucocorticoid metabolites in patients with primary aldosteronism, could explain some of the metabolic abnormalities seen in patients with aldosterone hypersecretion. In clinical practice, patients with unexplained osteoporosis, particularly when associated with other features such as impaired glucose tolerance or hypertension, should be investigated for the possible presence of autonomous cortisol or aldosterone secretion due to an adrenal adenoma. Randomized intervention studies are needed, however, to investigate the optimum interventions for osteoporosis and other co-morbidities in these patients.

Secretoneurin suppresses cardiac hypertrophy through suppression of oxidant stress

The neuropeptide secretoneurin (SN) plays protective roles in myocardial ischemia. In the present study, the effect of SN in cardiac hypertrophy was investigated. We observed that, in isoproterenol (ISO) treatment induced cardiac or cardiomyocytes hypertrophy, a marked increase in the expression of endogenous SN in mouse plasma, myocardium and primary-cultured cardiomyocytes occurs. In hypertrophic mice, the heart size, heart weight/body weight (HW/BW) ratio, cardiomyocyte size, and atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) expression were significantly higher than those in controls but were effectively suppressed by SN gene therapy. Similarly, the protective effects of SN were also observed in cultured cardiomyocytes following ISO treatment. SN significantly increased the activity of catalase and superoxide dismutase (SOD) in parallel with the decrease in reactive oxygen species levels in cardiomyocytes. We observed that SN evoked the activation of all of the AMPK, P38/MAPK and ERK/MAPK pathways in cardiomyocytes, but pretreatment with only AMPK inhibitor (compound C) and ERK1/2/MAPK inhibitor (PD98059) counteracted the protective effects of SN against cardiomyocyte hypertrophy and the suppressive effects of SN on oxidant stress in cardiomyocytes. These results indicated that endogenous SN is induced in hypertrophic cardiomyocytes, and may play a protective role in the pathogenesis of cardiac hypertrophy. These results suggest that exogenous SN supplementation protects the cardiac hypertrophy induced by ISO treatment through the activation of AMPK and ERK/MAPK pathways, thus upregulating antioxidants and suppressing oxidative stress.

Homeostatic Left Heart integration and disintegration links atrio-ventricular covariation's dyshomeostasis in Hypertrophic Cardiomyopathy

Left ventricle and left atrium are and have been practically always analyzed separately in common clinically and non-clinically oriented cardiovascular investigations. Both classic and speckle tracking echocardiographic data contributed to the knowledge about deformational impairments occurring in systo-diastolic differences. Recently new trajectory based approaches allowed a greater awareness about the entire left ventricle or left atrium revolution and on their deficiencies that take place in presence of hypertrophic cardiomyopathy. However, surprisingly, the concomitant function of the two left heart chambers has not been analyzed for their geometrical/mechanical relationship. For the first time we study here, by acquiring left ventricle and left atrial geometries on the same heartbeat, the trajectory attributes of the entire left heart treated as a whole shape and the shape covariation of its two subunits. We contrasted healthy subjects with patients affected by hypertrophic cardiomyopathy. We found impaired left heart trajectory mainly in terms of orientation and size. More importantly, we found profound differences in the direction of morphological covariation of left ventricle and left atrium. These findings open to new perspectives in pathophysiological evaluation of different diseases by allowing the appreciation of concomitant functioning of both left heart whole geometry and of its two chambers.

Risk of Fracture in Primary Aldosteronism: A Population-Based Cohort Study

Primary aldosteronism (PA) is associated with increased urinary calcium excretion and osteoporosis prevalence. We studied the long-term effect of hyperaldosterone on fracture risk and possible risk mitigation via treatments, by comparing PA patients and their essential hypertension (EH) counterparts extracted by propensity score match. We used a longitudinal population database from the Taiwan National Health Insurance, and used a validated algorithm to identify PA patients diagnosed in 1997-2010. Our sample included 2533 PA patients, including 921 patients with aldosterone-producing adenoma (APA). Our methods for assessing excessive fracture risk included multivariable Cox regression and the competing risk regression. The incidence rate of fracture at any site was 14.4 per 1000 person-years for PA, and 11.2 per 1000 person-years for APA. In contrast, the incidence rate of fracture at any site was 8.3 per 1000 person-years in EH controls for PA, and 6.5 per 1000 person-years in EH controls for APA. Mineralocorticoid receptor antagonist (MRA) treatment might be associated with higher risk of osteoporotic fracture in the whole female PA cohort (subdistribution hazard ratio [SHR] = 2.12, p = 0.008) as well as female APA patients (SHR = 1.15, p = 0.049). As to fracture at any site, MRA treatment was also associated with higher risk; the SHR was 1.88 (p < 0.001) in the whole female PA cohort, and 2.17 (p = 0.019) in female APA patients. PA is tightly associated with higher risk of bone fracture, even in the case where the competing risk of death was controlled. Particularly, female PA patients treated with MRA were confronted with significantly higher risk in bone fracture than their EH controls. © 2017 American Society for Bone and Mineral Research.

Dyshomeostasis, obesity, addiction and chronic stress

When eating control is overridden by hedonic reward, a condition of obesity dyshomeostasis occurs. Appetitive hedonic reward is a natural response to an obesogenic environment containing endemic stress and easily accessible and palatable high-energy foods and beverages. Obesity dyshomeostasis is mediated by the prefrontal cortex, amygdala and hypothalamic-pituitary-adrenal axis. The ghrelin axis provides the perfect signalling system for feeding dyshomeostasis, affect control and hedonic reward. Dyshomeostasis plays a central role in obesity causation, the addictions and chronic conditions and in persons with diverse bodies. Prevention and treatment efforts that target sources of dyshomeostasis provide ways of reducing adiposity, ameliorating the health impacts of addiction and raising the quality of life in people suffering from chronic stress.

Parathyroid Gland Function in Primary Aldosteronism

Primary aldosteronism (PA) is the most frequent cause of secondary arterial hypertension. Beyond its effects on intravascular volume and blood pressure, PA causes metabolic alterations and a higher cardiovascular morbidity, which is reduced by PA-directed therapy. Experimental studies demonstrated that mineralocorticoid excess may also influence mineral homeostasis. A role in cardiovascular disease has also been attributed to parathyroid hormone (PTH). Increasing evidence supports a bidirectional interaction between aldosterone and PTH.Primary hyperparathyroidism is associated with arterial hypertension and an increased cardiovascular morbidity and mortality, which might be associated to higher aldosterone values; parathyreoidectomy results in lowered aldosterone and blood pressure levels. PA leads to secondary hyperparathyroidism, which is reversible by PA-directed therapy. A lower bone mineral density and a higher fracture rate were also shown to be reversible by PA-directed therapy. There is a suspicion of a bidirectional interaction between aldosterone and PTH, which might lead to a higher cardiovascular risk. There are more and more reports about coincident PA and primary hyperparathyroidism. From a pathophysiologic point of view this constellation is best characterized as tertiary hyperparathyroidism. Future aspects should further clarify the extent of these endocrine interactions and analyze the influence of this interplay on cardiovascular morbidity and mortality and bone health.

Association of serum parathyrine and calcium levels with primary aldosteronism: a meta-analysis

Primary aldosteronism (PA) represents major cause of secondary hypertension, strongly associated with high cardiovascular morbidity and mortality. Aldosterone excess may influence mineral homeostasis, through higher urinary calcium (Ca) excretion reducing calcium plasma levels and leading to secondary increase of parathyrine (PTH). The purpose of the present study is to clarify the association of serum PTH and Ca levels with PA using a metaanalysis approach. We searched articles indexed in the PubMed, OVID and Sciencedirect published as of September 2014 that met our predefined criteria. Six articles with 748 subjects from 8 case-control studies were identified. Overall, pooled analysis indicated that subjects with PA had higher serum PTH concentrations and lower Ca levels than controls with essential hypertension (EH) (PTH: SMD = 1.146, 95% CI = [0.774, 1.518]; Ca: SMD = -0.698, 95% CI = [-1.102,-0.294]). Further subgroup analysis stratified by geological location found a similar pattern both in Italy and Austria (Italy: for PTH, SMD = 1.176, 95% CI = [0.758, 1.593], for Ca, SMD = -0.669, 95% CI = [-1.119,-0.219]; Austria: for PTH, SMD = 1.004, 95% CI = [0.359, 1.648], for Ca, SMD = -0.900, 95% CI = [-1.543,-0.257]). In addition, the subgroup analysis stratified by type of Ca measurement also found a similar pattern by spectrophotometry (SMD = -1.078, 95% CI = [-1.532, -0.623]), but not by ion selective electrode (SMD = -0.248, 95% CI = [-0.810, 0.315]). Sensitivity analysis showed that excluding any one study from the pooled analysis did not vary the results substantially. No evidence of publication bias was observed. In conclusion, this meta-analysis supports a significant association of PTH and Ca concentration with PA. Therefore, the high levels of PTH and low Ca concentrations in serum can be used as a variable predictor for PA.

Clinical and echocardiographic correlates of serum copper and zinc in acute and chronic heart failure

AIM

Emerging evidence suggests a pathophysiological role of micronutrient dyshomeostasis in heart failure, including promotion of adverse remodeling and clinical deterioration. We sought to evaluate serum copper (Cu) and zinc (Zn) levels in acute (AHF) and chronic (CHF) heart failure.

METHODS

We studied 125 patients, 71 % male, aged 69 ± 11 years, 37 % with preserved left ventricular ejection fraction (LVEF ≥40 %) (HFPEF), including 81 with AHF and 44 with CHF; 21 healthy volunteers served as controls. Serum Cu and Zn levels were determined using air-acetylene flame atomic absorption spectrophotometry.

RESULTS

Serum Cu levels were significantly higher in AHF (p = 0.006) and CHF (p = 0.002) patients compared to controls after adjusting for age, gender and comorbidities, whereas they did not differ between AHF and CHF (p = 0.840). Additionally, serum Cu in patients with LVEF <40 % was significantly higher compared to both controls (p < 0.001) and HFPEF patients (p = 0.003). Serum Zn was significantly lower in AHF (p < 0.001) and CHF (p = 0.039) compared to control after adjusting for the above-mentioned variables. Moreover, serum Zn was significantly lower in AHF than in CHF (p = 0.015). In multiple linear regression, LVEF (p = 0.033) and E/e ratio (p = 0.006) were independent predictors of serum Cu in total heart failure population, while NYHA class (p < 0.001) and E/e ratio (p = 0.007) were independent predictors of serum Zn.

CONCLUSION

Serum Cu was increased both in AHF and CHF and correlated with LV systolic and diastolic function. Serum Zn, in contrast, was decreased both in AHF and CHF and independently predicted by clinical status and LV diastolic function.

Can parathyroid hormone be used as a biomarker for heart failure?

Secondary hyperparathyroidism in heart failure is a consequence of renin-angiotensin-aldosterone activation, chronic hyperaldosteronism, and loop diuretic usage, resulting in calcium excretion. The result is an inflammatory state with adverse effects on myocardial remodeling and systemic complications. Recent literature has suggested that elevated parathyroid hormone predicts adverse outcomes in patients with heart failure independent of serum calcium and phosphate, vitamin D deficiency, and renal insufficiency. Parathyroid hormone has been correlated with elevated brain natriuretic peptide levels, an established biomarker of heart failure severity. There are several limitations to the utilization of parathyroid hormone as a biomarker for heart failure, and further prospective studies need to be conducted to assess the value of multiple parathyroid hormone measurements over time and elucidate the role of parathyroid hormone in diastolic dysfunction. Pending further validation, there is promise for parathyroid hormone as a complementary biomarker in heart failure.

Phosphoproteome mapping of cardiomyocyte mitochondria in a rat model of heart failure

Mitochondria are complex organelles essential to cardiomyocyte survival. Protein phosphorylation is emerging as a key regulator of mitochondrial function. In the study reported here, we analyzed subsarcolemmal (SSM) mitochondria harvested from rats who have received 4 weeks of aldosterone/salt treatment to simulate the neurohormonal profile of human congestive heart failure. Our objective was to obtain an initial qualitative inventory of the phosphoproteins in this biologic system. SSM mitochondria were harvested, and the phosphoproteome was analyzed with a gel-free bioanalytical platform. Mitochondrial proteins were digested with trypsin, and the digests were enriched for phosphopeptides with immobilized metal ion affinity chromatography. The phosphopeptides were analyzed by ion trap liquid chromatography-tandem mass spectrometry, and the phosphoproteins identified via database searches. Based on MS/MS and MS(3) data, we characterized a set of 42 phosphopeptides that encompassed 39 phosphorylation sites. These peptides mapped to 26 proteins, for example, long-chain specific acyl-CoA dehydrogenase, Complex III subunit 6, and mitochondrial import receptor TOM70. Collectively, the characterized phosphoproteins belong to diverse functional modules, including bioenergetic pathways, protein import machinery, and calcium handling. The phosphoprotein panel discovered in this study provides a foundation for future differential phosphoproteome profiling toward an integrated understanding of the role of mitochondrial phosphorylation in heart failure.

Bone health and aldosterone excess

A picture of hyperparathyroidism secondary to increased urinary calcium excretion was found in 116 patients with primary aldosteronism (PA), compared with 110 essential hypertensives. After medical or surgical treatment in 40 PA patients, parathyroid hormone (PTH) levels were significantly reduced and bone mineral density (BMD) significantly increased at the lumbar spine, femoral neck, and total hip.

INTRODUCTION

Recent studies have shown that aldosterone induces urinary calcium excretion leading to a reduction of calcemia with consequent secondary hyperparathyroidism and BMD loss. In patients with PA, this picture of hyperparathyroidism is significantly improved by treatment with adrenal surgery or with mineralocorticoid receptor antagonists. On these premises, the aim of the present study was to evaluate calcium and phosphate metabolism parameters in PA patients, compared with patients with essential hypertension (EH) and the effect of treatment of aldosterone excess on bone health in PA patients.

METHODS

We studied 226 patients: 116 with PA (46 with an aldosterone-producing adenoma and 70 with bilateral adrenal hyperplasia) and 110 patients with EH. In 40 patients with PA, we evaluated biochemical parameters and bone mass, using the dual-energy X-ray absorptiometry, at baseline and after a mean follow-up of 24 months from treatment.

RESULTS

In PA patients, compared with EH, PTH levels and urinary calcium excretion significantly increased while serum calcium significantly decreased with comparable vitamin D levels. At follow-up in PA patients, PTH levels were significantly reduced compared with basal evaluation, despite similar vitamin D amounts. At follow-up, we observed a significant improvement of the Z-score at the lumbar spine, femoral neck, and at total hip sites.

CONCLUSIONS

Our results support previous data showing secondary hyperparathyroidism in PA patients, which is reversible after treatment. Moreover, this targeted treatment appears to be able to determine a significant improvement of BMD both at the spine and hip sites.

Mineralocorticoid receptor antagonism confers cardioprotection in heart failure

The symptoms and signs constituting the congestive heart failure (CHF) syndrome have their pathophysiologic origins rooted in a salt-avid renal state mediated by effector hormones of the renin-angiotensin-aldosterone and adrenergic nervous systems. Controlled clinical trials, conducted over the past decade in patients having minimally to markedly severe symptomatic heart failure, have demonstrated the efficacy of a pharmacologic regimen that interferes with these hormones, including aldosterone receptor binding with either spironolactone or eplerenone. Potential pathophysiologic mechanisms, which have not hitherto been considered involved for the salutary responses and cardioprotection provided by these mineralocorticoid receptor antagonists, are reviewed herein. In particular, we focus on the less well-recognized impact of catecholamines and aldosterone on monovalent and divalent cation dyshomeostasis, which leads to hypokalemia, hypomagnesemia, ionized hypocalcemia with secondary hyperparathyroidism and hypozincemia. Attendant adverse cardiac consequences include a delay in myocardial repolarization with increased propensity for supraventricular and ventricular arrhythmias, and compromised antioxidant defenses with increased susceptibility to nonischemic cardiomyocyte necrosis.

Intermedin suppresses pressure overload cardiac hypertrophy through activation of autophagy

Left ventricular hypertrophy is a maladaptive response to pressure overload and an important risk factor for heart failure. Intermedin (IMD), a multi-functional peptide, plays important roles in cardiovascular protection. In this study, we revealed an autophagy-dependent mechanism involved in IMD’s protection against cardiac remodeling and cardiomyocyte death in heart hypertrophy. We observed that transverse aortic contraction (TAC) induction, Ang II or ISO exposure induced remarkable increase in the expression of endogenous IMD and its receptor components, CRLR, RAMP1 and RAMP3, in mouse hearts and H9c2 cell cultures, respectively. Furthermore, the heart size, heart weight/body weight ratios, cardiomyocyte size and apoptosis, interstitial collagen, hypertrophic markers including ANP and BNP expression were also significantly increased, which were effectively suppressed by IMD supplementation. In addition, IMD induced capillary angiogenesis and improved functions in hypertrophic hearts. We further observed that IMD induced strong autophagy in hypertrophic hearts and cultured cells, which was paralleling with the decrease in cardiomyocyte size and apoptosis. Furthermore, an autophagy inhibitor, 3-MA, was used to block the IMD-augmented autophagy level, and then the protection of IMD on cardiomyocyte hypertrophy and apoptosis was almost abrogated. We also observed that IMD supplementation stirred intracellular cAMP production, and augmented the ERK1/2 phosphorylation induced by Ang II/ISO exposure in H9c2 cells. In addition, we inhibited PI3K, PKA and MAPK/ERK1/2 signaling pathways by using wortamannin, H89 and PD98059, respectively, in H9c2 cells co-incubating with both IMD and Ang II or ISO, and observed that these inhibitors effectively reduced IMD-augmented autophagy level, but only H89 and PD98059 pre-incubation abrogated the anti-apoptotic action of IMD. These results indicate that the endogenous IMD and its receptor complexes are induced in hypertrophic cardiomyocytes and proposed to play an important role in the pathogenesis of cardiac hypertrophy, and the autophagy stirred by IMD supplementation is involved in its protection against cardiomyocyte hypertrophy and apoptosis through the activation of both cAMP/PKA and MAPK/ERK1/2 pathways.

Cardiovascular diseases in older patients with osteoporotic hip fracture: prevalence, disturbances in mineral and bone metabolism, and bidirectional links

BACKGROUND

Considerable controversy exists regarding the contribution of mineral/bone metabolism abnormalities to the association between cardiovascular diseases (CVDs) and osteoporotic fractures.

AIMS AND METHODS

To determine the relationships between mineral/bone metabolism biomarkers and CVD in 746 older patients with hip fracture, clinical data were recorded and serum concentrations of parathyroid hormone (PTH), 25-hydroxyvitamin D, calcium, phosphate, magnesium, troponin I, parameters of bone turnover, and renal, liver, and thyroid functions were measured.

RESULTS

CVDs were diagnosed in 472 (63.3%) patients. Vitamin D deficiency was similarly prevalent in patients with (78.0%) and without (82.1%) CVD. The CVD group had significantly higher mean PTH concentrations (7.6 vs 6.0 pmol/L, P < 0.001), a higher prevalence of secondary hyperparathyroidism (SPTH) (PTH > 6.8 pmol/L, 43.0% vs 23.3%, P < 0.001), and excess bone resorption (urinary deoxypyridinoline corrected by creatinine [DPD/Cr] > 7.5 nmol/μmol, 87.9% vs 74.8%, P < 0.001). In multivariate regression analysis, SHPT (odds ratio [OR] 2.6, P = 0.007) and high DPD/Cr (OR 2.8, P = 0.016) were independent indictors of CVD. Compared to those with both PTH and DPD/Cr in the normal range, multivariate-adjusted ORs for the presence of CVD were 17.3 (P = 0.004) in subjects with SHPT and 9.7 (P < 0.001) in patients with high DPD/Cr. CVD was an independent predicator of SHPT (OR 2.8, P = 0.007) and excess DPD/Cr (OR 2.5, P = 0.031). CVD was predictive of postoperative myocardial injury, while SHPT was also an independent predictor of prolonged hospital stay and in-hospital death.

CONCLUSION

SHPT and excess bone resorption are independent pathophysiological mediators underlying the bidirectional associations between CVD and hip fracture, and therefore are important diagnostic and therapeutic targets.

Bone involvement in aldosteronism

In rats with aldosteronism, a reduction of bone mineral density (BMD) and cortical bone strength has been reported. Our study was aimed to evaluate bone involvement in patients with primary aldosteronism (PA). A total of 188 consecutive subjects with adrenal incidentaloma, observed between November 2009 and October 2011, were screened for PA with aldosterone-to-renin ratio. After confirmatory tests, in those who screened positive, 11 patients were diagnosed as PA and 15 patients were not (nPA). A serum/urinary biochemical profile, parathyroid hormone (PTH), BMD measured at lumbar spine (LS) and total and femoral neck (TN and FN) by dual X-ray absorptiometry, and conventional spinal radiographs (T(4) -L(4) ) were obtained in all subjects. PA patients had a significantly higher 24-hour urinary calcium (6.28 ± 1.85 versus 4.28 ± 1.18 mmol/d; p < 0.01), and PTH (9.8 [5.8-14.6], median [range] versus 5.3 [2.5-10.8] pmol/L; p < 0.01) than nPA patients. BMD expressed as Z-value at LS (-1.18 ± 0.99 versus 0.22 ± 1.12), FN (-0.85 ± 0.73 versus 0.01 ± 0.82), and TN (-0.49 ± 0.61 versus 0.39 ± 0.93) was lower in PA than in nPA (p = 0.003, p = 0.011, and p = 0.012, respectively). The prevalence of osteoporosis was higher in PA than in nPA (8/11, 72.7% versus 3/15, 20.0%; Fisher's exact test: p = 0.015). Vertebral fractures tended to be more prevalent in PA than in nPA (5/11, 45.5% versus 2/15, 13.3%; Fisher's exact test: p = 0.095). Logistic regression analysis showed that osteoporosis and morphometric vertebral fractures were associated with PA (odds ratio [OR], 15.4; 95% confidence interval [CI] = 1.83-130, p = 0.012; and OR, 30.4; 95%CI, 1.07-862, p = 0.045, respectively) regardless of age, body mass index (BMI), and LS-BMD. In 9 of 11 PA patients, 6 months after beginning of treatment (surgery or spironolactone) there was a significant reduction of urinary calcium excretion (p < 0.01) and PTH (p < 0.01), whereas in 5 of 11 PA patients, 1 year after beginning of treatment, BMD was significantly increased at LS, p < 0.01). In conclusion, PA is associated with osteoporosis, vertebral fractures, and increased urinary calcium excretion.

Dynamics of bone turnover markers in patients with heart failure and following haemodynamic improvement through ventricular assist device implantation

AIMS

Abnormal bone metabolism and progressive demineralization have been described in patients with heart failure (HF). We hypothesized that mechanical unloading through implantation of a ventricular assist device (VAD) with subsequent haemodynamic improvement would correct abnormal bone metabolism in patients with advanced HF.

METHODS AND RESULTS

Serum was collected from 14 controls, 20 patients with moderate HF, 34 patients with advanced HF undergoing VAD implantation, and 34 patients at the time of VAD explantation (mean duration: 169 ± 125 days). Bone metabolism markers were measured using enzyme-linked immunosorption assay (ELISA) or chemiluminescence immunoassay (CLIA). Compared with controls, HF patients showed increased parathyroid hormone (PTH: 42 ± 19 vs. 117 ± 117 pg/mL in HF; P < 0.02) with decreased 25-hydroxyvitamin D [25(OH)D: 29 ± 14 vs. 21 ± 11 ng/mL in HF; P = 0.05]. While procollagen-1 N-terminal peptide (P1NP) and osteocalcin were similar, cross-linked C- and N-telopeptides of type I collagen (CTX and NTX) were both higher in HF (NTX: 14 ± 6 vs. 20 ± 11 ng/mL; P < 0.05; CTX: 0.35 ± 0.13 vs. 1.05 ± 0.78 ng/mL; P < 0.01 for controls and HF, respectively). P1NP increased markedly after VAD implantation (49 ± 37 vs. 121 ± 62 ng/mL; P < 0.0001), with a mild decrease in CTX and NTX levels indicating a shift towards anabolic bone formation. Serum PTH correlated with estimated glomerular filtration rate (r = -0.245, P < 0.05).

CONCLUSION

Patients with advanced HF are characterized by increased levels of biochemical markers of bone resorption potentially as a result of secondary hyperparathyroidism and uncoupling of bone remodelling. Haemodynamic improvement and mechanical unloading after VAD implantation lead to correction of bone metabolism and increased levels of anabolic bone formation markers.

Mitochondria play a central role in nonischemic cardiomyocyte necrosis: common to acute and chronic stressor states

The survival of cardiomyocytes must be ensured as the myocardium adjusts to a myriad of competing physiological and pathophysiological demands. A significant loss of these contractile cells, together with their replacement by stiff fibrillar collagen in the form of fibrous tissue accounts for a transition from a usually efficient muscular pump into one that is failing. Cellular and subcellular mechanisms involved in the pathogenic origins of cardiomyocyte cell death have long been of interest. This includes programmed molecular pathways to either necrosis or apoptosis, which are initiated from ischemic or nonischemic origins. Herein, we focus on the central role played by a mitochondriocentric signal-transducer-effector pathway to nonischemic cardiomyocyte necrosis, which is common to acute and chronic stressor states. We begin by building upon the hypothesis advanced by Albrecht Fleckenstein and coworkers some 40 years ago based on the importance of calcitropic hormone-mediated intracellular Ca(2+) overloading, which predominantly involves subsarcolemmal mitochondria and is the signal to pathway activation. Other pathway components, which came to be recognized in subsequent years, include the induction of oxidative stress and opening of the mitochondrial inner membrane permeability transition pore. The ensuing loss of cardiomyocytes and consequent replacement fibrosis, or scarring, represents a disease of adaptation and a classic example of when homeostasis begets dyshomeostasis.

Intracellular calcium overloading and oxidative stress in cardiomyocyte necrosis via a mitochondriocentric signal-transducer-effector pathway

Congestive heart failure (CHF), a common clinical syndrome, has reached epidemic proportions. Its disabling symptoms account for frequent hospitalizations and readmissions. Pathophysiological mechanisms that lead to CHF and account for its progressive nature are of considerable interest. Important scientific observations obtained from Dr Pawan K Singal's laboratory in Winnipeg, Manitoba, have provided crucial insights to our understanding of the pathophysiological factors that contribute to cardiomyocyte necrosis (the heart is a postmitotic organ incapable of tolerating an ongoing loss of these cells without adverse functional consequences). This increment in knowledge and the mechanistic insights afforded by Dr Singal and his colleagues have highlighted the role of excessive intracellular calcium accumulation and the appearance of oxidative stress in CHF, in which the rate of reactive oxygen species generation overwhelms their rate of detoxification by antioxidant defenses. They have shown that this common pathophysiological scenario applies to diverse entities such as ischemia/reperfusion and hypoxia/reoxygenation forms of injury, myocardial infarction and the cardiomyopathies that accompany diabetes and excess levels of catecholamines and adriamycin. The authors are honoured to be invited to contribute to the present focus issue of Experimental & Clinical Cardiology in recognizing Dr Singal's numerous scholarly accomplishments. The present article reviews the authors' recent work on a mitochondriocentric signal-transducer-effector pathway to cardiomyocyte necrosis found in rats with either an acute stressor state that accompanies isoproterenol administration or a chronic stressor state manifested after four weeks of aldosterone/salt treatment.