Safety and tolerability of one-year intramuscular testosterone regime to induce puberty in older men with CHH.

We present herein our 20-year experience of pubertal induction in apubertal older (median age 56 years; range 38.4-69.5) men with congenital hypogonadotrophic hypogonadism (n = 7) using a simple fixed-dose and fixed-interval intramuscular testosterone that we originally pioneered in relation to achieving virilisation of natal female transgender men. This regime was effective and well tolerated, resulting in complete virilisation by around 1 year after treatment initiation. No physical or psychological adverse effects were encountered in this group of potentially vulnerable individuals. There were no abnormal excursions of laboratory parameters and extended follow-up beyond the first year of treatment revealed remarkable improvements in bone density. We highlight advantages to both patients and physicians of this regime in testosterone-naïve older men with congenital hypogonadism and discourage the over-rigid application to such patients of treatment algorithms derived from paediatric practice in relation to the evaluation and management in younger teenagers with delayed puberty of uncertain cause.

Prognostic Value of Cardiovascular Magnetic Resonance and Single-Photon Emission Computed Tomography in Suspected Coronary Heart Disease: Long-Term Follow-up of a Prospective, Diagnostic Accuracy Cohort Study.

BACKGROUND: There are no prospective, prognostic data comparing cardiovascular magnetic resonance (CMR) and single-photon emission computed tomography (SPECT) in the same population of patients with suspected coronary heart disease (CHD). OBJECTIVE: To establish the ability of CMR and SPECT to predict major adverse cardiovascular events (MACEs). DESIGN: Annual follow-up of the CE-MARC (Clinical Evaluation of MAgnetic Resonance imaging in Coronary heart disease) study for a minimum of 5 years for MACEs (cardiovascular death, acute coronary syndrome, unscheduled revascularization or hospital admission for cardiovascular cause). (Current Controlled Trials registration: ISRCTN77246133). SETTING: Secondary and tertiary care cardiology services. PARTICIPANTS: 752 patients from the CE-MARC study who were being investigated for suspected CHD. MEASUREMENTS: Prediction of time to MACE was assessed by using univariable (log-rank test) and multivariable (Cox proportional hazards regression) analysis. RESULTS: 744 (99%) of the 752 recruited patients had complete follow-up. Of 628 who underwent CMR, SPECT, and the reference standard test of X-ray angiography, 104 (16.6%) had at least 1 MACE. Abnormal findings on CMR (hazard ratio, 2.77 [95% CI, 1.85 to 4.16]; P < 0.001) and SPECT (hazard ratio, 1.62 [CI, 1.11 to 2.38; P = 0.014) were both strong and independent predictors of MACE. Only CMR remained a significant predictor after adjustment for other cardiovascular risk factors, angiography result, or stratification for initial patient treatment. LIMITATION: Data are from a single-center observational study (albeit conducted in a high-volume institution for both CMR and SPECT). CONCLUSION: Five-year follow-up of the CE-MARC study indicates that compared with SPECT, CMR is a stronger predictor of risk for MACEs, independent of cardiovascular risk factors, angiography result, or initial patient treatment. This further supports the role of CMR as an alternative to SPECT for the diagnosis and management of patients with suspected CHD. PRIMARY FUNDING SOURCE: British Heart Foundation.

Phaeochromocytoma and ACTH-dependent cushing's syndrome: tumour crf secretion can mimic pituitary cushing's disease.

INTRODUCTION: 10% of corticotrophin (ACTH)-dependent Cushing's syndrome arises from secretion by extrapituitary tumours, with phaeochromocytoma implicated in a few cases. Ectopic secretion by phaeochromocytoma of corticotropin-releasing hormone (CRF), with secondary corticotroph hyperplasia, is even rarer, with only five cases in the literature hitherto. However, such cases may be classified as 'ectopic ACTH' due to incomplete verification. CLINICAL CASES: We describe three patients with phaeochromocytoma and ACTH-dependent Cushing's syndrome in whom biochemical cure was achieved following unilateral adrenalectomy. Although unable to access a validated CRF assay within the timeframe for sample storage, we nevertheless inferred CRF secretion in 2 of 3 cases by tumour immunostaining (positive for CRF; negative for ACTH), supported in one case by pre-operative inferior petrosal sinus sampling (IPSS) indicative of pituitary ACTH source. Both cases were characterized by rapid postoperative wean off glucocorticoids, presumed to reflect the pituitary stimulatory-effect of CRF outweighing central negative feedback inhibition by hypercortisolaemia. By contrast, the tumour excised in a third case exhibited positive immunostaining for ACTH - negative for CRF - and postoperative recovery of hypothalamic-pituitary-adrenal axis took significantly longer. DISCUSSION: Ectopic CRF production is biochemically indistinguishable from ectopic ACTH secretion, except that IPSS mimics pituitary Cushing's disease and cortisol dynamics may normalize rapidly postadrenalectomy. CRF secretion can be inferred through tumour immunohistochemistry, even if no CRF assay is available. Unrecognized phaeochromocytoma ACTH secretion may underpin some cases of cardiovascular collapse postadrenalectomy through acute hypocortisolaemia. Despite advances in phaeochromocytoma genetics since previous reports, we were unable to identify somatic DNA defects associated with either ACTH or CRF secretion.

A state of reversible compensated ventricular dysfunction precedes pathological remodelling in response to cardiomyocyte-specific activity of angiotensin II type-1 receptor in mice.

Cardiac dysfunction is commonly associated with high-blood-pressure-induced cardiomyocyte hypertrophy, in response to aberrant renin-angiotensin system (RAS) activity. Ensuing pathological remodelling promotes cardiomyocyte death and cardiac fibroblast activation, leading to cardiac fibrosis. The initiating cellular mechanisms that underlie this progressive disease are poorly understood. We previously reported a conditional mouse model in which a human angiotensin II type-I receptor transgene (HART) was expressed in differentiated cardiomyocytes after they had fully matured, but not during development. Twelve-month-old HART mice exhibited ventricular dysfunction and cardiomyocyte hypertrophy with interstitial fibrosis following full receptor stimulation, without affecting blood pressure. Here, we show that chronic HART activity in young adult mice causes ventricular dysfunction without hypertrophy, fibrosis or cardiomyocyte death. Dysfunction correlated with reduced expression of pro-hypertrophy markers and increased expression of pro-angiogenic markers in the cardiomyocytes experiencing increased receptor load. This stimulates responsive changes in closely associated non-myocyte cells, including the downregulation of pro-angiogenic genes, a dampened inflammatory response and upregulation of Tgfß. Importantly, this state of compensated dysfunction was reversible. Furthermore, increased stimulation of the receptors on the cardiomyocytes caused a switch in the secondary response from the non-myocyte cells. Progressive cardiac remodelling was stimulated through hypertrophy and death of individual cardiomyocytes, with infiltration, proliferation and activation of fibroblast and inflammatory cells, leading to increased angiogenic and inflammatory signalling. Together, these data demonstrate that a state of pre-hypertrophic compensated dysfunction can exist in affected individuals before common markers of heart disease are detectable. The data also suggest that there is an initial response from the housekeeping cells of the heart to signals emanating from distressed neighbouring cardiomyocytes to suppress those changes most commonly associated with progressive heart disease. We suggest that the reversible nature of this state of compensated dysfunction presents an ideal window of opportunity for personalised therapeutic intervention.

Analysis of gene-gene interactions among common variants in candidate cardiovascular genes in coronary artery disease.

OBJECTIVE: Only a small fraction of coronary artery disease (CAD) heritability has been explained by common variants identified to date. Interactions between genes of importance to cardiovascular regulation may account for some of the missing heritability of CAD. This study aimed to investigate the role of gene-gene interactions in common variants in candidate cardiovascular genes in CAD. APPROACH AND RESULTS: 2,101 patients with CAD from the British Heart Foundation Family Heart Study and 2,426 CAD-free controls were included in the discovery cohort. All subjects were genotyped with the Illumina HumanCVD BeadChip enriched for genes and pathways relevant to the cardiovascular system and disease. The primary analysis in the discovery cohort examined pairwise interactions among 913 common (minor allele frequency >0.1) independent single nucleotide polymorphisms (SNPs) with at least nominal association with CAD in single locus analysis. A secondary exploratory interaction analysis was performed among all 11,332 independent common SNPs surviving quality control criteria. Replication analyses were conducted in 2,967 patients and 3,075 controls from the Myocardial Infarction Genetics Consortium. None of the interactions amongst 913 SNPs analysed in the primary analysis was statistically significant after correction for multiple testing (required P<1.2x10-7). Similarly, none of the pairwise gene-gene interactions in the secondary analysis reached statistical significance after correction for multiple testing (required P = 7.8x10-10). None of 36 suggestive interactions from the primary analysis or 31 interactions from the secondary analysis was significant in the replication cohort. Our study had 80% power to detect odds ratios > 1.7 for common variants in the primary analysis. CONCLUSIONS: Moderately large additive interactions between common SNPs in genes relevant to cardiovascular disease do not appear to play a major role in genetic predisposition to CAD. The role of genetic interactions amongst less common SNPs and with medium and small magnitude effects remain to be investigated.

Elevated expression levels of miR-143/5 in saphenous vein smooth muscle cells from patients with Type 2 diabetes drive persistent changes in phenotype and function.

Type 2 diabetes (T2DM) promotes premature atherosclerosis and inferior prognosis after arterial reconstruction. Vascular smooth muscle cells (SMC) respond to patho/physiological stimuli, switching between quiescent contractile and activated synthetic phenotypes under the control of microRNAs (miRs) that regulate multiple genes critical to SMC plasticity. The importance of miRs to SMC function specifically in T2DM is unknown. This study was performed to evaluate phenotype and function in SMC cultured from non-diabetic and T2DM patients, to explore any aberrancies and investigate underlying mechanisms. Saphenous vein SMC cultured from T2DM patients (T2DM-SMC) exhibited increased spread cell area, disorganised cytoskeleton and impaired proliferation relative to cells from non-diabetic patients (ND-SMC), accompanied by a persistent, selective up-regulation of miR-143 and miR-145. Transfection of premiR-143/145 into ND-SMC induced morphological and functional characteristics similar to native T2DM-SMC; modulating miR-143/145 targets Kruppel-like factor 4, alpha smooth muscle actin and myosin VI. Conversely, transfection of antimiR-143/145 into T2DM-SMC conferred characteristics of the ND phenotype. Exposure of ND-SMC to transforming growth factor beta (TGFß) induced a diabetes-like phenotype; elevated miR-143/145, increased cell area and reduced proliferation. Furthermore, these effects were dependent on miR-143/145. In conclusion, aberrant expression of miR-143/145 induces a distinct saphenous vein SMC phenotype that may contribute to vascular complications in patients with T2DM, and is potentially amenable to therapeutic manipulation.

Residual adrenal function in autoimmune Addison's disease: improvement after tetracosactide (ACTH1-24) treatment.

CONTEXT: Despite lifelong steroid hormone replacement, there is excess morbidity and mortality associated with autoimmune Addison's disease. In health, adrenocortical cells undergo continuous self-renewal from a population of subcapsular progenitor cells, under the influence of ACTH, suggesting a therapeutic possibility. OBJECTIVE: We aimed to determine whether tetracosactide (synthetic ACTH1-24) could revive adrenal steroidogenic function in autoimmune Addison's disease. DESIGN, SETTING, AND PATIENTS: Thirteen patients (aged 16-65 y) with established autoimmune Addison's disease for more than 1 year were recruited at the Newcastle University Clinical Research Facility. INTERVENTION: The intervention included a 20-week study of regular sc tetracosactide (ACTH1-24) therapy. MAIN OUTCOME MEASURES: Serum and urine corticosteroids were measured during medication withdrawal at baseline and every 5 weeks during the study. RESULTS: Serum cortisol levels remained less than 100 nmol/L in 11 of 13 participants throughout the study. However, two women achieved peak serum cortisol concentrations greater than 400 nmol/L after 10 and 29 weeks of tetracosactide therapy, respectively, allowing withdrawal of corticosteroid replacement. Concurrently, urine glucocorticoid and mineralocorticoid metabolite excretion increased from subnormal to above the median of healthy controls. One of these responders remains well with improving peak serum cortisol (672 nmol/L) 28 months after stopping all treatments. The other responder showed a gradual reduction in serum cortisol and aldosterone over time, and steroid therapy was recommenced after a 28-week period without glucocorticoid replacement. CONCLUSION: This is the first study to demonstrate that established autoimmune Addison's disease is amenable to a regenerative medicine therapy approach.

Predictive power of late gadolinium enhancement for myocardial recovery in chronic ischaemic heart failure: a HEART sub-study.

BACKGROUND: The amount of myocardial scar measured by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging predicts regional recovery in wall motion following revascularization. Previous studies have been conducted in patients with a relatively recent myocardial insult and relatively preserved left ventricular (LV) function. In this sub-study of a clinical trial, the predictive value of LGE, and other CMR-derived data, for myocardial recovery in patients with chronic severe ischaemic cardiomyopathy was assessed. METHODS: Twenty-two patients with severe LV impairment of ischaemic origin were enrolled as a sub-study of a trial that randomly assigned patients to revascularization or not in addition to guideline-indicated pharmacological therapy. Patients underwent a CMR study at baseline and 6 months. Scans were qualitatively and quantitatively assessed for wall motion, rest/stress myocardial perfusion, and LGE. RESULTS: The median duration of heart failure was 13 (inter-quartile range 5-21) months. Patients had severe LV dilatation [end-diastolic volume (EDV) 280 ± 77 mL] and reduction in LV ejection fraction (LVEF) (29 ± 10%). The percentage scar burden by LGE was 17 ± 9%. Patient characteristics of those undergoing revascularization (n = 7) or not (n = 14) were similar. Myocardial perfusion reserve index (MPRI) improved following revascularization (MPRI 1.17 vs. 1.57, P < 0.0001) but not following medical therapy (1.39 vs. 1.32, P = 0.54). However, LVEF improved in patients whether or not they had revascularization. In the revascularization group, 14% of dysfunctional segments with LGE <25% and 22% of dysfunctional segments with LGE <50% had improved contractile function. However, the transmural extent of LGE did not predict contractile recovery following revascularization or pharmacological therapy (P = 0.19, P = 0.42). LVEDV improved overall (280 ± 77 to 269 ± 83 mL, P = 0.05); improvement was associated with heart failure duration (P = 0.04). CONCLUSIONS: In patients with chronic severe LV impairment of ischaemic origin, duration of heart failure is a better predictor of recovery than transmural extent of LGE, following medical therapy or successful revascularization. This suggests that the extent of myocardial remodelling is more important for LV recovery than the presence and extent of prior infarction alone and that LGE should not be the sole determinant of treatment method in severe LV systolic dysfunction of ischaemic origin.

Comparison of cardiovascular magnetic resonance and single-photon emission computed tomography in women with suspected coronary artery disease from the Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease (CE-MARC) Trial.

BACKGROUND: Coronary artery disease is the leading cause of death in women, and underdiagnosis contributes to the high mortality. This study compared the sex-specific diagnostic performance of cardiovascular magnetic resonance (CMR) and single-photon emission computed tomography (SPECT). METHODS AND RESULTS: A total of 235 women and 393 men with suspected angina underwent CMR, SPECT, and x-ray angiography as part of the Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease (CE-MARC) study. CMR comprised adenosine stress/rest perfusion, cine imaging, late gadolinium enhancement, and magnetic resonance coronary angiography. Gated adenosine stress/rest SPECT was performed with (99m)Tc-tetrofosmin. For CMR, the sensitivity in women and men was similar (88.7% versus 85.6%; P=0.57), as was the specificity (83.5% versus 82.8%; P=0.86). For SPECT, the sensitivity was significantly worse in women than in men (50.9% versus 70.8%; P=0.007), but the specificities were similar (84.1% versus 81.3%; P=0.48). The sensitivity in both the female and male groups was significantly higher with CMR than SPECT (P<0.0001 for both), but the specificity was similar (P=0.77 and P=1.00, respectively). For perfusion-only components, CMR outperformed SPECT in women (area under the curve, 0.90 versus 0.67; P<0.0001) and in men (area under the curve, 0.89 versus 0.74; P<0.0001). Diagnostic accuracy was similar in both sexes with perfusion CMR (P=1.00) but was significantly worse in women with SPECT (P<0.0001). CONCLUSIONS: In both sexes, CMR has greater sensitivity than SPECT. Unlike SPECT, there are no significant sex differences in the diagnostic performance of CMR. These findings, plus an absence of ionizing radiation exposure, mean that CMR should be more widely adopted in women with suspected coronary artery disease. CLINICAL TRIAL REGISTRATION URL: http://www.controlled-trials.com. Unique identifier: ISRCTN77246133.

Apolipoprotein(a) acts as a chemorepellent to human vascular smooth muscle cells via integrin αVß3 and RhoA/ROCK-mediated mechanisms.

Lipoprotein(a) (Lp(a)) is an independent risk factor for the development of cardiovascular disease. Vascular smooth muscle cell (SMC) motility and plasticity, functions that are influenced by environmental cues, are vital to adaptation and remodelling in vascular physiology and pathophysiology. Lp(a) is reportedly damaging to SMC function via unknown molecular mechanisms. Apolipoprotein(a) (apo(a)), a unique glycoprotein moiety of Lp(a), has been demonstrated as its active component. The aims of this study were to determine functional effects of recombinant apo(a) on human vascular SMC motility and explore the underlying mechanism(s). Exposure of SMC to apo(a) in migration assays induced a potent, concentration-dependent chemorepulsion that was RhoA and integrin αVß3-dependent, but transforming growth factor ß-independent. SMC manipulation through RhoA gene silencing, Rho kinase inhibition, statin pre-treatment, αVß3 neutralising antibody and tyrosine kinase inhibition all markedly inhibited apo(a)-mediated SMC migration. Our data reveal unique and potent activities of apo(a) that may negatively influence SMC remodelling in cardiovascular disease. Circulating levels of Lp(a) are resistant to lipid-lowering strategies and hence a greater understanding of the mechanisms underlying its functional effects on SMC may provide alternative therapeutic targets.

Cost-effectiveness of cardiovascular magnetic resonance in the diagnosis of coronary heart disease: an economic evaluation using data from the CE-MARC study.

OBJECTIVE: To evaluate the cost-effectiveness of diagnostic strategies for coronary heart disease (CHD) derived from the CE-MARC study. DESIGN: Cost-effectiveness analysis using a decision analytic model to compare eight strategies for the diagnosis of CHD. SETTING: Secondary care out-patients (Cardiology Department). PATIENTS: Patients referred to cardiologists for the further evaluation of symptoms thought to be angina pectoris. INTERVENTIONS: Eight different strategies were considered, including different combinations of exercise treadmill testing (ETT), single-photon emission CT (SPECT), cardiovascular magnetic resonance (CMR) and coronary angiography (CA). MAIN OUTCOME MEASURES: Costs expressed as UK sterling in 2010-2011 prices and health outcomes in quality-adjusted life-years (QALYs). The time horizon was 50 years. RESULTS: Based on the characteristics of patients in the CE-MARC study, only two strategies appear potentially cost-effective for diagnosis of CHD, both including CMR. The choice is between two strategies: one in which CMR follows a positive or inconclusive ETT, followed by CA if CMR is positive or inconclusive (Strategy 3 in the model); and the other where CMR is followed by CA if CMR is positive or inconclusive (Strategy 5 in the model). The more cost-effective of these two rests on the threshold cost per QALY gained below which health systems define an intervention as cost-effective. Strategy 3 appears cost-effective at the lower end of the threshold range used in the UK (£20 000 per QALY gained), while Strategy 5 appears cost-effective at the higher end of the threshold range (£30 000 per QALY). The results are robust to various sources of uncertainty although prior likelihood of CHD requiring revascularisation and the rate at which false negative patients are eventually appropriately identified do impact upon the results. CONCLUSIONS: The CE-MARC study showed that CMR had superior diagnostic accuracy to SPECT and concluded that CMR should be more widely used in the investigation of patients with CHD. The economic evaluation results show that using CMR is also a cost-effective strategy and supports the wider adoption of this modality.

Interleukin-1 has opposing effects on connective tissue growth factor and tenascin-C expression in human cardiac fibroblasts.

Cardiac fibroblasts (CF) play a central role in the repair and remodeling of the heart following injury and are important regulators of inflammation and extracellular matrix (ECM) turnover. ECM-regulatory matricellular proteins are synthesized by several myocardial cell types including CF. We investigated the effects of pro-inflammatory cytokines on matricellular protein expression in cultured human CF. cDNA array analysis of matricellular proteins revealed that interleukin-1α (IL-1α, 10ng/ml, 6h) down-regulated connective tissue growth factor (CTGF/CCN2) mRNA by 80% and up-regulated tenascin-C (TNC) mRNA levels by 10-fold in human CF, without affecting expression of thrombospondins 1-3, osteonectin or osteopontin. Western blotting confirmed these changes at the protein level. In contrast, tumor necrosis factor α (TNFα) did not modulate CCN2 expression and had only a modest stimulatory effect on TNC levels. Signaling pathway inhibitor studies suggested an important role for the p38 MAPK pathway in suppressing CCN2 expression in response to IL-1α. In contrast, multiple signaling pathways (p38, JNK, PI3K/Akt and NFκB) contributed to IL-1α-induced TNC expression. In conclusion, IL-1α reduced CCN2 expression and increased TNC expression in human CF. These observations are of potential value for understanding how inflammation and ECM regulation are linked at the level of the CF.

Reproducibility of first-pass cardiovascular magnetic resonance myocardial perfusion.

PURPOSE: To assess the reproducibility of semiquantitative and quantitative analysis of first-pass myocardial perfusion cardiovascular magnetic resonance (CMR) in healthy volunteers. MATERIALS AND METHODS: Eleven volunteers underwent myocardial perfusion CMR during adenosine stress and rest on 2 separate days. Perfusion data were acquired in a single mid-ventricular section in two cardiac phases to permit cardiac phase reproducibility comparisons. Semiquantitative analysis was performed to derive normalized upslopes of myocardial signal intensity profiles (myocardial perfusion index, MPI). The quantitative analysis estimated absolute myocardial blood flow (MBF) using Fermi-constrained deconvolution. The perfusion reserve index was calculated by dividing stress by rest data. Two observers performed all the measurements independently. One observer repeated all first scan measurements 4 weeks later. RESULTS: The reproducibility of perfusion CMR was highest for semiquantitative analysis with an intraobserver coefficient of variability (CoV) of 3%-7% and interobserver CoV of 4%-10%. Semiquantitative interstudy comparison was less reproducible (CoV of 13%-27%). Quantitative intraobserver CoV of 10%-18%, interobserver CoV of 8%-15% and interstudy CoV of 20%-41%. Reproducibility of systolic and diastolic phases and the endocardial and epicardial myocardial layer showed similar reproducibility on both semiquantitative and quantitative analysis. CONCLUSION: The reproducibility of CMR myocardial perfusion estimates is good, but varies between intraobserver, interobserver, and interstudy comparisons. In this study semiquantitative analysis was more reproducible than quantitative analysis.

p38 MAPK alpha mediates cytokine-induced IL-6 and MMP-3 expression in human cardiac fibroblasts.

Pre-clinical studies suggest that the p38 MAPK signaling pathway plays a detrimental role in cardiac remodeling, but its role in cardiac fibroblast (CF) function is not well defined. We aimed to identify the p38 MAPK subtypes expressed by human CF, study their activation in response to proinflammatory cytokines, and determine which subtypes were important for expression of specific cytokines and matrix metalloproteinases (MMPs). Quantitative real-time RT-PCR analysis of mRNA levels in human CF cultured from multiple patients revealed a consistent pattern of expression with p38α being most abundant, followed by p38γ, then p38δ and only low expression of p38ß (3% of p38α mRNA levels). Immunoblotting confirmed marked protein expression of p38α, γ and δ, with little or no expression of p38ß. Phospho-ELISA and combined immunoprecipitation/immunoblotting techniques demonstrated that the proinflammatory cytokines IL-1α and TNFα selectively activated p38α and p38γ, but not p38δ. Selective p38α siRNA gene silencing reduced IL-1α-induced IL-6 and MMP-3 mRNA expression and protein secretion, without affecting IL-1α-induced IL-1ß and MMP-9 mRNA expression. In conclusion, human CF express the α, γ and δ subtypes of p38 MAPK, and the α subtype is important for IL-1α-induced IL-6 and MMP-3 expression in this cell type.

Hypertensive left ventricular hypertrophy: a mechanistic approach to optimizing regression assessed by cardiovascular magnetic resonance.

OBJECTIVES: Neuroendocrine activation may be an important adjunctive mechanism for left ventricular hypertrophy (LVH) development. Controversy exists to as to whether LVH regression occurs due to blood pressure (BP) reduction alone or if adjunctive mechanisms play a role. We planned to test the hypothesis that for a similar BP reduction, LVH regression would be greater using a drug combination selected specifically to reduce neuroendocrine activity compared with one that did not. METHODS: Forty-two patients with hypertension and cardiovascular magnetic resonance (CMR) proven LVH were allocated to one of two equipotent antihypertensive regimens for 6 months. Treatments were chosen on the basis of opposing mechanistic actions on the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system (SNS); one arm inhibitory (valsartan and moxonidine), the other neutral (bendroflumethiazide and amlodipine). The primary end point was absolute reduction in CMR-determined left ventricular mass (LVM). RESULTS: All BP indices were highly comparable at the start and end of the trial (P > 0.6 between groups). BP was reduced (always P < 0.0001) by 37/17  mmHg in the valsartan and moxonidine group and 38/19  mmHg in the bendroflumethiazide and amlodipine group. CMR quantified LVM was comparable between the two groups at baseline and decreased significantly in both treatment groups (P < 0.0001). Reduction in LVM was significantly greater in valsartan and moxonidine [-25.9  g; 95% confidence interval (CI) -31.6 to -20.2] compared with bendroflumethiazide and amlodipine (-18.3  g; -23.3 to -13.4) (P < 0.05). CONCLUSION: The magnitude of LVH regression achieved by inhibiting the RAAS and SNS neuroendocrine pathways is greater than that produced by comparable BP reduction alone. This supports the hypothesis that neuroendocrine mechanisms are important in the regression of LVH.

Inhibition of platelet-derived growth factor receptor signaling regulates Oct4 and Nanog expression, cell shape, and mesenchymal stem cell potency.

Defining the signaling mechanisms that regulate the fate of adult stem cells is an essential step toward their use in regenerative medicine. Platelet-derived growth factor receptor (PDGFR) signaling plays a crucial role in specifying mesenchymal stem cell (MSC) commitment to mesenchymal lineages. Based on the hypothesis that selective inhibition of signaling pathways involved in differentiation may increase stem cell potency, we examined the role of PDGFR signaling in controlling the fate of human MSCs. Using a small molecular PDGFR inhibitor that induced MSCs toward a more rounded shape, expression of Oct4 and Nanog were markedly upregulated. In these PDGFR inhibitor-treated MSCs, Oct4 and Nanog expression and cell shape were regulated by janus kinase (JAK), MAPK kinase (MEK), and epidermal growth factor receptor (EGFR) signaling. Under defined differentiation conditions, these PDGFR-inhibited MSCs expressed definitive endodermal, ectodermal, and mesodermal markers. We also confirmed that depletion of individual PDGF receptors upregulated expression of Oct4A and Nanog. This study identifies PDGFR signaling as a key regulator of Oct4 and Nanog expression and of MSC potency. Thus, inhibiting these specific receptor tyrosine kinases, which play essential roles in tissue formation, offers a novel approach to unlock the therapeutic capacity of MSCs.

MMP-3 (5A/6A) polymorphism does not influence human smooth muscle cell invasion.

BACKGROUND: Stromelysin (MMP-3) is an important regulator of vascular smooth muscle cell (SMC) invasion, a key contributor to saphenous vein (SV) bypass graft failure. The 5A allele of the common -1612 MMP-3 5A/6A promoter polymorphism reportedly confers increased promoter activity, MMP-3 tissue expression, and susceptibility to a number of vascular pathologies. The aim of this study was to determine whether the MMP-3 5A/6A polymorphism directly influences endogenous MMP-3 expression levels and, consequently, cell invasion, in SV-derived SMC cultured from patients with different genotypes. MATERIAL AND METHODS: Genotyping of 226 patients revealed -1612 MMP-3 5A/6A genotype frequencies of 20.8% 5A/5A, 52.7% 5A/6A, and 26.5% 6A/6A. Using a standardized, controlled protocol, we investigated cytokine- and growth factor-induced MMP-3 expression (real-time polymerase chain reaction [RT-PCR], ELISA) and SV-SMC invasion (Boyden chamber with Matrigel barrier) using cultured SV-SMC from patients with different MMP-3 genotypes. RESULTS: Despite observing a strong correlation between MMP-3 mRNA levels and MMP-3 protein secretion, no significant differences were apparent in MMP-3 expression levels or cell invasion between cells with different MMP-3 5A/6A genotypes. CONCLUSIONS: Our data suggest that the MMP-3 5A/6A promoter polymorphism in isolation does not influence levels of MMP-3 secretion or cellular invasion in human SV-SMC.

The α(2C)-Del322-325 adrenoceptor polymorphism and the occurrence of left ventricular hypertrophy in hypertensives.

OBJECTIVES: Sympathetic activation has a role in the development of left ventricular hypertrophy (LVH). The presynaptic α(2C)-adrenoceptor inhibits the release of norepinephrine from sympathetic nerve terminals in the heart. A deletion polymorphism in the α(2C)-adrenoceptor (α(2C)Del322-325) generates a hypofunctional α(2C)-adrenoceptor, which may result in chronic adrenergic signalling. This study aimed to investigate whether the α(2C)Del322-325 polymorphism was associated with an increased prevalence of LVH in patients with systemic hypertension. METHODS: Left ventricular mass was measured in 205 patients with systemic hypertension and 60 normal volunteers using a 1.5-T Philips MRI system. Genotyping was performed using a restriction fragment length polymorphism assay. RESULTS: No significant difference was observed between the distribution of the α(2C)Del322-325 genotypes in hypertensive patients with LVH compared with those without LVH. Adjusting for confounding variables the odds ratio (OR) of being ins/del for the α(2C)Del322-325 and having LVH was 0.49 (95% CI 0.14-1.69, p = 0.256). CONCLUSIONS: These observations suggest that there is little evidence for an association between α(2C)Del322-325 polymorphism and an increased prevalence of LVH in patients with systemic hypertension.