Phosphodiesterase-5 inhibition and cardioprotection: potential role of hydrogen sulfide

Background Our laboratory has shown that phosphodiesterase-5 (PDE-5) inhibitors including sildenafil, vardenafil and tadalafil induce powerful protection against myocardial ischemia-reperfusion injury. We have shown that sildenafil protects through activation PKC, expression of eNOS/iNOS, protein kinase G (PKG) and opening of mitochondrial KATP (mitoKATP) channels [1]. Hydrogen sulfide (H2S) is a gaseous molecule that is produced enzymatically and exerts physiological actions in the cardiovascular system. Similar to PKG, H2S has been shown to protect the heart via opening of mitoKATP channel [2]. In the current study, we hypothesized that tadalafil, the long acting inhibitor of PDE-5 mediates cardioprotection through H2S signaling in a PKG-dependent fashion. Methods and results After baseline transthoracic echocardiography (TTE), adult ICR mice were injected i.p. with vehicle (10% DMSO) or tadalafil (1 mg/kg) with or without KT5823 (KT, PKG blocker, 1 mg/kg) or dl-propargylglycine [PAG, Cystathionine-γ-lyase (CSE, H2S-producing enzyme) blocker; 50 mg/kg] 1 h prior to coronary artery ligation for 30 min and reperfusion for 24 h, whereas C57BL-wild type and CSE-knockout mice were treated with either vehicle or tadalafil. After reperfusion, TTE was performed and hearts were collected for infarct size (IS) measurement using TTC staining. Survival was increased with tadalafil (95%) compared with control (65%, P \u3c 0.05). Infarct size was reduced with tadalafil (13.2 ± 1.7%) compared to vehicle (40.6 ± 2.5%; P \u3c 0.05). KT and PAG abolished tadalafil-induced protection (IS: 39.2 ± 1% and 51.2 ± 2.4%, respectively) similar to genetic deletion of CSE (47.2 ± 5.1%). Moreover, tadalafil preserved fractional shortening (FS: 31 ± 1.5%) compared to control (FS: 22 ± 4.8%, P \u3c 0.05). Baseline FS was 44 ± 1.7%. KT and PAG abrogated the preservation of LV function with tadalafil by decline in FS to 17 ± 1% and 23 ± 3%, respectively. Compared to vehicle, myocardial H2S production was significantly increased with tadalafil and was abolished with KT. Conclusion PKG activation with tadalafil limits myocardial infarction and preserves LV function through H2S signaling

The cost-effectiveness of the Argus II retinal prosthesis in Retinitis Pigmentosa patients

Background: Retinitis Pigmentosa (RP) is a hereditary genetic disease causing bilateral retinal degeneration. RP is a leading cause of blindness resulting in incurable visual impairment and drastic reduction in the Quality of life of the patients. Second Sight Medical Products Inc. developed Argus II, a retinal prosthesis system for treating RP. Argus II is the world’s first ever-commercial implant intended to restore some vision in the blind patients. The objective of this study was to assess the cost-effectiveness of the Argus® II Retinal Prosthesis System (Argus II) in Retinitis Pigmentosa (RP) patients. Method: A multi -state transition Markov model was developed to determine the cost-effectiveness of Argus II versus usual care in RP from the perspective of healthcare payer. A hypothetical cohort of 1000 RP patients aged 46 years followed up over a (lifetime) 25-year time horizon. Health outcomes were expressed as quality adjusted life years (QALYs) and direct healthcare costs expressed in 2012 €. Results are reported as incremental cost per ratios (ICERs) with outcomes and costs discounted at an annual rate of 3.5%. Results: The ICER for Argus II was €14,603/QALY. Taking into account the uncertainty in model inputs the ICER was €14,482/QALY in the probabilistic analysis. In the scenarios of an assumption of no reduction on cost across model visual acuity states or a model time horizon as short as 10 years the ICER increased to €31,890/QALY and €49,769/QALY respectively. Conclusion: This economic evaluation shows that Argus II is a cost-effective intervention compared to usual care of the RP patients. The lifetime analysis ICER for Argus II falls below the published societal willingness to pay of EuroZone countries

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Effectiveness of a national quality improvement programme to improve survival after emergency abdominal surgery (EPOCH): a stepped-wedge cluster-randomised trial

Background: Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients. Methods: We did a stepped-wedge cluster-randomised trial of patients aged 40 years or older undergoing emergency open major abdominal surgery. Eligible UK National Health Service (NHS) hospitals (those that had an emergency general surgical service, a substantial volume of emergency abdominal surgery cases, and contributed data to the National Emergency Laparotomy Audit) were organised into 15 geographical clusters and commenced the QI programme in a random order, based on a computer-generated random sequence, over an 85-week period with one geographical cluster commencing the intervention every 5 weeks from the second to the 16th time period. Patients were masked to the study group, but it was not possible to mask hospital staff or investigators. The primary outcome measure was mortality within 90 days of surgery. Analyses were done on an intention-to-treat basis. This study is registered with the ISRCTN registry, number ISRCTN80682973. Findings: Treatment took place between March 3, 2014, and Oct 19, 2015. 22 754 patients were assessed for elegibility. Of 15 873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 patients in the usual care group and 7374 in the QI group. Eight patients in the usual care group and nine patients in the QI group were not included in the analysis because of missing primary outcome data. The primary outcome of 90-day mortality occurred in 1210 (16%) patients in the QI group compared with 1393 (16%) patients in the usual care group (HR 1·11, 0·96–1·28). Interpretation: No survival benefit was observed from this QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. Future QI programmes should ensure that teams have both the time and resources needed to improve patient care. Funding: National Institute for Health Research Health Services and Delivery Research Programme

Effectiveness of a national quality improvement programme to improve survival after emergency abdominal surgery (EPOCH): a stepped-wedge cluster-randomised trial

BACKGROUND: Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients. METHODS: We did a stepped-wedge cluster-randomised trial of patients aged 40 years or older undergoing emergency open major abdominal surgery. Eligible UK National Health Service (NHS) hospitals (those that had an emergency general surgical service, a substantial volume of emergency abdominal surgery cases, and contributed data to the National Emergency Laparotomy Audit) were organised into 15 geographical clusters and commenced the QI programme in a random order, based on a computer-generated random sequence, over an 85-week period with one geographical cluster commencing the intervention every 5 weeks from the second to the 16th time period. Patients were masked to the study group, but it was not possible to mask hospital staff or investigators. The primary outcome measure was mortality within 90 days of surgery. Analyses were done on an intention-to-treat basis. This study is registered with the ISRCTN registry, number ISRCTN80682973. FINDINGS: Treatment took place between March 3, 2014, and Oct 19, 2015. 22 754 patients were assessed for elegibility. Of 15 873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 patients in the usual care group and 7374 in the QI group. Eight patients in the usual care group and nine patients in the QI group were not included in the analysis because of missing primary outcome data. The primary outcome of 90-day mortality occurred in 1210 (16%) patients in the QI group compared with 1393 (16%) patients in the usual care group (HR 1·11, 0·96-1·28). INTERPRETATION: No survival benefit was observed from this QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. Future QI programmes should ensure that teams have both the time and resources needed to improve patient care. FUNDING: National Institute for Health Research Health Services and Delivery Research Programme

Cervical intradural disc herniation and cerebrospinal fluid leak

Cervical intradural disc herniation (IDH) is a rare condition and only 25 cases of cervical have been reported. We report a 45-year-old male who presented with sudden onset right lower limb weakness after lifting heavy weight. Magnetic resonance imaging of the cervical spine showed C5/6 disc prolapse with intradural extension. The patient underwent C5/6 discectomy through anterior cervical approach. Postoperatively, the patient improved in stiffness but developed cerebrospinal fluid leak and the leak resolved with multiple lumbar punctures