Safety and Cost-Effectiveness of Same-Day Cardiac Resynchronization Therapy and Implantable Cardioverter Defibrillator Implantation

Cardiac resynchronization therapy (CRT) and implantable cardioverter defibrillator (ICD) implantation improve morbidity and mortality in selected patients. Many centers still admit patients overnight. We evaluated the safety, feasibility, and cost savings of same-day CRT/ICD device implantation by performing a retrospective study of all consecutive elective CRT/ICD implants at a tertiary center from January 2009 to April 2013. All emergency and/or inpatient cases were excluded. Data were collected on baseline demographics, implantation indication, procedure details, complications (categorized as immediate [≤24 hours], short term [24 hours to 6 weeks], medium term [6 weeks to 4 months], and long term [>4 months]), and mortality (30 day and 1 year). Comparisons were made between those having planned same-day versus overnight stay procedures. A cost analysis was performed to evaluate cost savings of the same-day policy. A total of 491 devices were implanted during this period: 267 were elective (54 planned overnight, 213 planned same-day) of which 229 were CRT pacemakers or CRT defibrillators and 38 ICDs. There were 26 total overall complications (9.7%) with no significant differences between planned same-day versus planned overnight stay cohorts (9.4% vs 11.1%, p = 0.8) and specifically no differences in immediate, short-, medium-, and long-term complications at follow-up. The 30-day and 1-year mortality rates did not differ between the two groups. An overnight stay at our hospital costs $450 (£300); our cost saving during this period was $91,800 (£61,200). Same-day CRT/ICD implantation is safe, feasible, and associated with significant cost savings. It provides significant advantages for patients and health care providers, especially given the current financial climate.

Orexin receptors exert a neuroprotective effect in Alzheimer's disease (AD) via heterodimerization with GPR103

Orexins are neuropeptides that regulate the sleep-wake cycle and feeding behaviour. QRFP is a newly discovered neuropeptide which exerts similar orexigenic activity, thus playing an important role in energy homeostasis and regulation of appetite. The exact expression and signalling characteristics and physiological actions of QRFP and its receptor GPR103 are poorly understood. Alzheimer's disease (AD) patients experience increased nocturnal activity, excessive daytime sleepiness, and weight loss. We hypothesised therefore that orexins and QRFP might be implicated in the pathophysiology of AD. We report that the down-regulation of hippocampal orexin receptors (OXRs) and GPR103 particularly in the cornu ammonis (CA) subfield from AD patients suffering from early onset familial AD (EOFAD) and late onset familial AD (LOAD). Using an in vitro model we demonstrate that this downregulation is due to to Aβ-plaque formation and tau hyper-phosphorylation. Transcriptomics revealed a neuroprotective role for both orexins and QRFP. Finally we provide conclusive evidence using BRET and FRET that OXRs and GPR103 form functional hetero-dimers to exert their effects involving activation of ERK1/2. Pharmacological intervention directed at the orexigenic system may prove to be an attractive avenue towards the discovery of novel therapeutics for diseases such as AD and improving neuroprotective signalling pathways.

Microvesicle-mediated release of soluble LH/hCG receptor (LHCGR) from transfected cells and placenta explants

Placental hCG and pitutary LH transduce signals in target tissues through a common receptor (LHCGR). We demonstrate that recombinant LHCGR proteins which include the hormone-binding domain are secreted from transfected cells and that natural LHCGR is also secreted from human placental explants. LHCGR recombinant proteins representing varying lengths of the N-terminal extracellular domain were expressed in Chinese Hamster Ovary cells in suspension culture. Secretion was minimal up to 72h but by 96h 24-37% of the LHCGR had been released into the culture medium. The secreted proteins were folded and sensitive to glycosidases suggesting N-linked glycosylation. Secretion was independent of recombinant size and was mediated via structurally defined membrane vesicles (50-150nm). Similarly cultured human early pregnancy placental explants also released LHCGR via microvesicles. These studies provide the first experimental evidence of the possible mechanistic basis of the secretion of LHCGR.

Postoperative hypocalcemia--the difference a definition makes

BACKGROUND

Review of the literature reveals considerable variability in the definitions and criteria used for reporting postoperative hypocalcemia. The lack of standardization prevents a meaningful comparison of results and performance locally with the national standard. It also prevents the pooling of data when performing meta-analysis, and may affect the comparison of research results.

METHODS

A literature review was performed to identify the different definitions used to define hypocalcemia in post-thyroidectomy patients. We analyzed the incidence of hypocalcemia in the same cohort of 202 post thyroidectomy patients using these definitions.

RESULTS

The reported hypocalcemia rates varied from 0% to 46% for the same cohort depending on the definition of hypocalcemia used. Only one-third of biochemically hypocalcemic patients requested calcium supplementation.

CONCLUSION

This study demonstrates the need for more uniformity and standardization in the definitions used for reporting hypocalcemia rates.

Relationship between cerebrospinal fluid visfatin (PBEF/Nampt) levels and adiposity in humans

OBJECTIVE

Observations of elevated circulating concentrations of visfatin (PBEF/Nampt) in obesity and diabetes suggest that this recently described adipokine is involved in the regulation of body weight and metabolism. We examined in humans whether visfatin is found in cerebrospinal fluid (CSF) and, if so, how CSF visfatin concentrations relate to adiposity and metabolic parameters.

RESEARCH DESIGN AND METHODS

We measured visfatin concentrations in the plasma and CSF of 38 subjects (18 men and 20 women; age 19-80 years) with a wide range of body weight (BMI 16.24-38.10 kg/m2). In addition, anthropometric parameters and endocrine markers were assessed. Bivariate correlation coefficients were determined and stepwise multiple regression analyses were performed to detect associations of CSF and plasma visfatin levels with relevant parameters.

RESULTS

Plasma visfatin levels increased with rising BMI (P < 0.0001) and body fat mass (P < 0.0001). In contrast, CSF visfatin levels decreased with increasing plasma visfatin concentrations (P < 0.03), BMI (P < 0.001), body fat mass (P < 0.0001), and insulin resistance (P < 0.05). Body fat was the only factor independently associated with CSF visfatin, explaining 58% of the variation of CSF visfatin levels (P < 0.0001). Neither plasma (P > 0.13) nor CSF (P > 0.61) visfatin concentrations differed between men and women.

CONCLUSIONS

Our data indicate that visfatin concentrations in human CSF decrease with rising body fat, supporting the assumption that visfatin transport across the blood-brain barrier is impaired in obesity and that central nervous visfatin insufficiency or resistance are linked to pathogenetic mechanisms of obesity.

Mouse models for preeclampsia: disruption of redox-regulated signaling

The concept that oxidative stress contributes to the development of human preeclampsia has never been tested in genetically-defined animal models. Homozygous deletion of catechol-O-methyl transferase (Comt-/-) in pregnant mice leads to human preeclampsia-like symptoms (high blood pressure, albuminurea and preterm birth) resulting from extensive vasculo-endothelial pathology, primarily at the utero-fetal interface where maternal cardiac output is dramatically increased during pregnancy. Comt converts estradiol to 2-methoxyestradiol 2 (2ME2) which counters angiogenesis by depleting hypoxia inducible factor-1 alpha (HIF-1 alpha) at late pregnancy. We propose that in wild type (Comt++) pregnant mice, 2ME2 destabilizes HIF-1 alpha by inhibiting mitochondrial superoxide dismutase (MnSOD). Thus, 2ME2 acts as a pro-oxidant, disrupting redox-regulated signaling which blocks angiogenesis in wild type (WT) animals in physiological pregnancy. Further, we suggest that a lack of this inhibition under normoxic conditions in mutant animals (Comt-/-) stabilises HIF-1 alpha by inactivating prolyl hydroxlases (PHD). We predict that a lack of inhibition of MnSOD, leading to persistent accumulation of HIF-1 alpha, would trigger inflammatory infiltration and endothelial damage in mutant animals. Critical tests of this hypothesis would be to recreate preeclampsia symptoms by inducing oxidative stress in WT animals or to ameliorate by treating mutant mice with Mn-SOD-catalase mimetics or activators of PHD.

Comparison of maternal ghrelin and leptin in healthy mothers and mothers with Type 1 diabetes

AIMS

Maternal leptin affects placental growth hormone (GH), whereas ghrelin, a natural ligand of the growth-hormone-secretagogue receptor, modulates GH action. Both hormones may affect fetal growth, and dysregulation in diabetes may lead to fetal growth disturbances. The aim was to investigate changes in maternal ghrelin during pregnancy with diabetes and to establish reference leptin levels.

METHODS

Twelve healthy non-diabetic (ND) and 12 pregnant women with Type 1 diabetes (T1DM) were recruited. Age and body mass index (BMI) [ND: age 29.9 +/- 4.7 years (mean +/- sd), BMI 25.2 +/- 3.7 kg/m2; T1DM: age 31 +/- 5.5 years, BMI 27 +/- 3.1 kg/m2] were similar in the groups. HbA1c in T1DM was 6.2 +/- 1.1% at 20 weeks, 6.3 +/- 1.1% at 30 weeks' gestation and 7.8 +/- 2.1% postpartum. Fasting plasma ghrelin, total leptin, free leptin (FL) and soluble leptin receptor (sOB-R) levels were measured at 20 and 30 weeks' gestation and postpartum and determined by radioimmunoassay.

RESULTS

All pregnancies resulted in full-term singleton births with no differences in birth weight between groups [T1DM: 3.4 +/- 0.56 kg (mean +/- SE); ND: 3.6 +/- 0.3 kg, P = NS]. Ghrelin levels were lower in T1DM when corrected for age and mothers' weight (T1DM: 458 +/- 36 pg/ml and 432.9 +/- 26.6 pg/ml; ND: 562 +/- 52 pg/ml and 515.8 +/- 63 pg/ml at 20 and 30 weeks, respectively, P < 0.05). T1DM mothers had higher levels of sOB-R and FL levels declined at 30 weeks' gestation in T1DM (P = 0.04) but not in ND.

CONCLUSION

In a population of pregnant women with expected changes in leptin levels as previously reported, ghrelin levels were lower in T1DM pregnancies at 20 and 30 weeks. This may have implications for fetal development and requires further study in diabetes, particularly in pregnancies that result in macrosomia.

Asymmetrical dimethylarginine, inflammatory and metabolic parameters in women with polycystic ovary syndrome before and after metformin treatment

CONTEXT

Insulin resistance plays a significant role in the pathogenesis of the polycystic ovary syndrome (PCOS) and represents a link to the unfavorable cardiovascular risk profile frequently found in affected patients. The endogenous nitric oxide synthase inhibitor asymmetrical dimethyl-L-arginine (ADMA) is associated with atherosclerosis and represents an independent marker for cardiovascular morbidity and mortality.

OBJECTIVE

We investigated ADMA levels among other cardiovascular, metabolic, and hormonal parameters in women with PCOS and the effects of metformin treatment on these parameters.

DESIGN

A cross-sectional study and clinical trial were performed.

PATIENTS AND PARTICIPANTS

Women with PCOS (n = 83) compared with a control group of healthy women (n = 39) were studied.

INTERVENTIONS

In a subgroup of patients with PCOS (n = 21), the effect of metformin was assessed after 6 months of treatment.

MAIN OUTCOME MEASURES

ADMA, intima media thickness (IMT), metabolic and hormonal parameters, and markers of inflammation were investigated.

RESULTS

ADMA levels were significantly higher in the PCOS group compared with controls (0.57 +/- 0.15 vs. 0.50 +/- 0.11; P = 0.024). Androgens, C-reactive protein, fasting C-peptide, area under the curve (AUC) insulin, AUC glucose, homeostatic assessment of insulin resistance, fasting insulin, glycosylated hemoglobin, cholesterol, low-density lipoprotein cholesterol, triglycerides, and IMT were significantly higher in women with PCOS compared with controls. In PCOS patients ADMA was found to be positively correlated with body mass index (BMI), waist to hip ratio, parameters of insulin sensitivity, hyperandrogenemia (free testosterone, free androgen index), and IMT. Treatment with metformin ameliorated hyperandrogenemia and decreased ADMA levels (0.53 +/- 0.06 vs. 0.46 +/- 0.09, P = 0.013). Decrease in ADMA levels subsequent to metformin treatment did not correlate with change in BMI or metabolic parameters.

CONCLUSIONS

ADMA amd parameters of insulin sensitivity are elevated in women with PCOS and the degree of insulin resistance confers the greatest influence on ADMA level. Metformin treatment led to improvement of hormonal and metabolic parameters and decreased ADMA levels possibly independent of BMI and metabolic changes.

[Polycystic ovary syndrome. Prototype of a cardio-metabolic syndrome]

Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting women in the reproductive age and is a major cause of anovulation, hyperandrogenism and infertility. Since obesity and insulin resistance are predominant features of women with PCOS, a variety of metabolic disturbances are associated. There is a marked increase in the risk of developing type-2 diabetes in these patients and a majority of women with PCOS will subsequently harbour an enhanced cardiovascular risk.

Differential responses of corticotropin-releasing hormone receptor type 1 variants to protein kinase C phosphorylation

Corticotropin-releasing hormone (CRH) regulates diverse biological functions in mammals, through activation of two types of specific G protein-coupled receptors that are expressed as multiple mRNA spliced variants. In most cells, the type 1alpha CRH receptor (CRH-R1alpha) preferentially activates the G(s)-adenylyl cyclase signaling cascade. CRH-R1alpha-mediated signaling activity is impaired by insertion of 29 amino acids in the first intracellular loop, a sequence modification that is characteristic of the human-specific CRH-R1beta variant. In various tissues, CRH signaling events are regulated by protein kinase C (PKC). The CRH receptors contain multiple putative PKC phosphorylation sites that represent potential targets. To investigate this, we expressed recombinant CRH-R1alpha or CRH-R1beta in human embryonic kidney 293 cells and analyzed signaling events after PKC activation. Agonist (oxytocin) or phorbol 12-myristate 13-acetate-induced activation of PKC led to phosphorylation of both CRH-R1 variants. However, CRH-R1alpha and CRH-R1beta exhibited different functional responses to PKC-induced phosphorylation, with only the CRH-R1beta susceptible to cAMP signaling desensitization. This was associated with a significant decrease of accessible CRH-R1beta receptors expressed on the cell surface. Both CRH-R1 variants were susceptible to homologous desensitization and internalization following treatment with CRH; however, PKC activation increased internalization of CRH-R1beta but not CRH-R1alpha in a beta-arrestin-independent manner. Our findings indicate that CRH-R1alpha and -R1beta exhibit differential responses to PKC-induced phosphorylation, and this might represent an important mechanism for functional regulation of CRH signaling in target cells.

Immunohistochemical and quantitative mRNA assessment of ghrelin expression in gastric and oesophageal adenocarcinoma

BACKGROUND

Ghrelin is an orexigenic gut peptide produced predominantly by the stomach. Gastric mucosal ghrelin production could be compromised by an infiltrating adenocarcinoma.

AIMS

To assess the expression of ghrelin mRNA and peptide in oesophagogastric adenocarcinomas and adjacent non-neoplastic mucosa.

METHODS

10 gastric and 22 oesophageal adenocarcinoma archival samples were randomly selected from a database. The presence of ghrelin-positive cells was assessed in cancer and corresponding non-neoplastic mucosa by immunohistochemistry. Quantitative reverse transcriptase polymerase chain reaction (PCR) for ghrelin mRNA was also performed on 24 gastric and 8 oesophageal adenocarcinoma specimens and adjacent non-neoplastic mucosa.

RESULTS

Immunohistochemistry and reverse transcriptase PCR confirm a negligible expression of ghrelin in adenocarcinoma specimens. By contrast, non-neoplastic gastric mucosa was rich in ghrelin-positive cells and ghrelin mRNA. The number (median and range) of ghrelin-positive cells per 2 mm section of non-neoplastic mucosa was 73 (45-215) in the corpus; this was significantly higher than in cardia mucosa (9 (0-64), p<0.001) and antral mucosa (5 (0-14), p<0.001).

CONCLUSIONS

Gastric and oesophageal adenocarcinomas have no ghrelin-producing cells. The highest level of ghrelin expression was noted in the non-neoplastic mucosa of the gastric corpus. Disruption of the gastric ghrelin-producing mechanism may occur during oesophagogastric malignancy.

Cardiovascular Risk Management by Blocking the Endocannabinoid System

The specific blockade of endocannabinoids at the level of the cannabinoid receptor 1 (CB (1) receptor) is a new therapeutic option to reduce body weight and manage cardiovascular risk. Although clinical trials are underway to document the safety and efficacy of this approach, much is still unknown about this endogenous system. Endocannabinoids and their receptors are expressed in the central nervous system as well as in the periphery and regulate the central neural circuits for food uptake and peripheral metabolic circuits. Within the context of food uptake, the stimulation of the CB (1) receptor with Delta (9)-tetrahydrocannabinol (Delta (9)-THC) enhances food consumption, while its blockade with receptor antagonists is an emerging relevant therapeutic means to reduce body weight. Rimonabant is the first of a new class of drugs that interferes with the endocannabinoid system by blocking the CB (1) receptor. In recent clinical studies, a substantial reduction in body weight and waist circumference was associated with an improvement of the cardiovascular risk profile. In particular, increased HDL cholesterol, decreased serum triglycerides and improved insulin sensitivity were observed. Further research will serve to establish the role of these compounds in cardiovascular risk management.

Corticotropin-releasing hormone receptors

Corticotropin-releasing hormone (CRH) and related peptides (urocortins, sauvagine, urotensin) play a central role in the co-ordination of autonomic, behavioural, cardiovascular, immune and endocrine responses to stressful stimuli. Their actions are mediated through activation of two types of G-protein-coupled receptors encoded by separate genes. In this review we focus on the diverse structural and functional characteristics of the family of CRH-like peptides and their receptors.

Signal transduction characteristics of the corticotropin-releasing hormone receptors in the feto-placental unit

Placentally derived CRH plays a major role in the mechanisms controlling human pregnancy and parturition. In this study, we sought to investigate the signal transduction mechanisms of CRH Type-1 receptors in the feto-placental unit. To clarify the signal transduction components in placenta and fetal membranes, we investigated the expression of G proteins and adenylate cyclase. Using the nonhydrolysable photoreactive analog [alpha-32P] GTP-azidoanilide and peptide antisera raised against G protein alpha-subunits, we studied coupling of CRH receptors to G proteins in both placental and fetal membranes. Treatment of placental membranes with human CRH (100 nM) increased the labeling of Gq, Go, and Gz but not Gi and Gs. Treatment of fetal membranes with human CRH (100 nM) increased the labeling of Go and Gq but not Gi, Gs, and Gz. These results were supported by experiments that showed that CRH failed to activate adenylate cyclase in these tissues, but induced an increase in inositol phosphates instead. These findings provide new insights into the components of the signal transduction machinery in both fetal and placental membranes and suggest that CRH Type-1 receptors can couple to different G proteins in different tissues. The physiological significance of these observations remains to be elucidated.