Orai1 Channel Inhibition Preserves Left Ventricular Systolic Function and Normal Ca2+ Handling After Pressure Overload.

BACKGROUND: Orai1 is a critical ion channel subunit, best recognized as a mediator of store-operated Ca2+ entry (SOCE) in nonexcitable cells. SOCE has recently emerged as a key contributor of cardiac hypertrophy and heart failure but the relevance of Orai1 is still unclear. METHODS: To test the role of these Orai1 channels in the cardiac pathophysiology, a transgenic mouse was generated with cardiomyocyte-specific expression of an ion pore-disruptive Orai1R91W mutant (C-dnO1). Synthetic chemistry and channel screening strategies were used to develop 4-(2,5-dimethoxyphenyl)-N-[(pyridin-4-yl)methyl]aniline (hereafter referred to as JPIII), a small-molecule Orai1 channel inhibitor suitable for in vivo delivery. RESULTS: Adult mice subjected to transverse aortic constriction (TAC) developed cardiac hypertrophy and reduced ventricular function associated with increased Orai1 expression and Orai1-dependent SOCE (assessed by Mn2+ influx). C-dnO1 mice displayed normal cardiac electromechanical function and cellular excitation-contraction coupling despite reduced Orai1-dependent SOCE. Five weeks after TAC, C-dnO1 mice were protected from systolic dysfunction (assessed by preserved left ventricular fractional shortening and ejection fraction) even if increased cardiac mass and prohypertrophic markers induction were observed. This is correlated with a protection from TAC-induced cellular Ca2+ signaling alterations (increased SOCE, decreased [Ca2+]i transients amplitude and decay rate, lower SR Ca2+ load and depressed cellular contractility) and SERCA2a downregulation in ventricular cardiomyocytes from C-dnO1 mice, associated with blunted Pyk2 signaling. There was also less fibrosis in heart sections from C-dnO1 mice after TAC. Moreover, 3 weeks treatment with JPIII following 5 weeks of TAC confirmed the translational relevance of an Orai1 inhibition strategy during hypertrophic insult. CONCLUSIONS: The findings suggest a key role of cardiac Orai1 channels and the potential for Orai1 channel inhibitors as inotropic therapies for maintaining contractility reserve after hypertrophic stress.

Piezo1 integration of vascular architecture with physiological force.

The mechanisms by which physical forces regulate endothelial cells to determine the complexities of vascular structure and function are enigmatic. Studies of sensory neurons have suggested Piezo proteins as subunits of Ca(2+)-permeable non-selective cationic channels for detection of noxious mechanical impact. Here we show Piezo1 (Fam38a) channels as sensors of frictional force (shear stress) and determinants of vascular structure in both development and adult physiology. Global or endothelial-specific disruption of mouse Piezo1 profoundly disturbed the developing vasculature and was embryonic lethal within days of the heart beating. Haploinsufficiency was not lethal but endothelial abnormality was detected in mature vessels. The importance of Piezo1 channels as sensors of blood flow was shown by Piezo1 dependence of shear-stress-evoked ionic current and calcium influx in endothelial cells and the ability of exogenous Piezo1 to confer sensitivity to shear stress on otherwise resistant cells. Downstream of this calcium influx there was protease activation and spatial reorganization of endothelial cells to the polarity of the applied force. The data suggest that Piezo1 channels function as pivotal integrators in vascular biology.

Pre-liver transplant biopsy in hepatocellular carcinoma: a potential criterion for exclusion from transplantation?

BACKGROUND: In cirrhotic patients with hepatocellular carcinoma (HCC), poor differentiation in pre-liver transplantation (LT) biopsy of the largest tumour is used as a criterion for exclusion from LT in some centres. The potential role of pre-LT biopsy at one centre was explored. METHODS: A prospective database of patients undergoing orthotopic LT for radiologically diagnosed HCC at St James's University Hospital, Leeds during 2006-2011 was analysed. RESULTS: A total of 60 predominantly male (85.0%) patients with viral hepatitis were identified. There were discrepancies between radiological and histopathological findings with respect to the number of tumours identified (in 27 patients, 45.0%) and their size (in 63 tumours, 64.3%). In four (6.7%) patients, the largest lesion, which would theoretically have been targeted for biopsy, was not the largest in the explant. Nine (31.0%) patients with multifocal HCC had tumours of differing grades. In two (6.9%) patients, the largest tumour was well differentiated, but smaller tumours in the explant were poorly differentiated. In one patient, the largest lesion was benign and smaller invasive tumours were confirmed histologically. CONCLUSIONS: The need to optimize selection for LT in HCC remains. In the present series, the largest tumour was not always representative of overall tumour burden or biological aggression and its potential use to exclude patients from LT is questionable.

Army health care operations in Iraq.

Four years of warfare in the urban environment of Iraq have produced fundamental changes in the Army's health-care system. First, improved communications and air evacuation have streamlined the transport of the wounded soldierfrom the battlefield to stateside medical centers. Second, individual ballistic armor has decreased the number of U.S. troops killed while the number of wounded soldiers has increased. Third, battling an unseen enemy has produced a marked increase in acute stress disorder, post-traumatic stress disorder and traumatic brain injury. Deployment of soldiers with chronic mental health disorders such as anxiety, attention deficit disorder, and depression is problematic. The stress of long combat tours has doubled the incidence of abuse and neglect in children of deployed service members. Comparedto active-componentsoldiers, the prevalence ofmental health disorders is twice as great in soldiers of the Army Reserve and Army National Guard. Finally, the difficulty in determining friend vs. foe in Iraq results in the incarceration of thousands of Iraqis creating both medical and ethical challenges for Army physicians.

Platelet membrane CD154 and sCD154 in progressive peripheral arterial disease: a pilot study.

OBJECTIVE: The expression and potential role of platelet membrane CD154 and sCD154 in atherosclerosis was investigated in patients with peripheral arterial disease. METHODS: This prospective observational study measured the expression of platelet-bound CD154 and soluble CD154 (sCD154) in 39 patients with critical limb ischaemia (CLI, n=15), stable intermittent claudication (SIC, n=12) and age-matched controls (AMC, n=12). Basal and agonist-stimulated CD154, P-selectin expression and fibrinogen binding was measured by whole blood flow cytometry, while sCD154 was measured in paired plasma samples by ELISA. RESULTS: Basal expression of CD154 on the platelet surface was enhanced in both groups of patients with peripheral arterial disease. However, the critical limb ischaemics showed the highest level of basal expression 0.7+/-0.3 [median+/-IQR] and was significantly increased compared to both stable intermittent claudicants and age-matched controls (P<0.001). On agonist stimulation with either ADP or thrombin critical limb ischaemics demonstrated greater platelet reactivity and propensity to express CD154 compared to age-matched controls (P<0.05). Confirmation of the cellular expression of CD154 results was obtained by measuring sCD154 concentrations in autologous plasma samples. Here plasma levels of sCD154 in critical limb ischaemics were significantly greater than both stable intermittent claudicants and age-matched controls (P<0.005). CONCLUSIONS: Enhanced basal platelet expression and increased propensity to express CD154 and sCD154 in critical limb ischaemics compared to both controls and patients with stable intermittent claudication support evidence for the role of CD154 in atherogenesis and suggest a novel function in progressive and acute peripheral arterial disease.

Upregulated WEE1 protects endothelial cells of colorectal cancer liver metastases.

Surgical resection of colorectal cancer liver metastases (CLM) can be curative, yet 80% of patients are unsuitable for this treatment. As angiogenesis is a determinant of CLM progression we isolated endothelial cells from CLM and sought a mechanism which is upregulated, essential for angiogenic properties of these cells and relevant to emerging therapeutic options. Matched CLM endothelial cells (CLMECs) and endothelial cells of normal adjacent liver (LiECs) were superficially similar but transcriptome sequencing revealed molecular differences, one of which was unexpected upregulation and functional significance of the checkpoint kinase WEE1. Western blotting confirmed that WEE1 protein was upregulated in CLMECs. Knockdown of WEE1 by targeted short interfering RNA or the WEE1 inhibitor AZD1775 suppressed proliferation and migration of CLMECs. Investigation of the underlying mechanism suggested induction of double-stranded DNA breaks due to nucleotide shortage which then led to caspase 3-dependent apoptosis. The implication for CLMEC tube formation was striking with AZD1775 inhibiting tube branch points by 83%. WEE1 inhibitors might therefore be a therapeutic option for CLM and could be considered more broadly as anti-angiogenic agents in cancer treatment.

Does the extent of lymphadenectomy, number of lymph nodes, positive lymph node ratio and neutrophil-lymphocyte ratio impact surgical outcome of perihilar cholangiocarcinoma?

BACKGROUND: Lymph node (LN) status is an important predictor of survival following resection of perihilar cholangiocarcinoma (PHCCA). Controversies still exist with regard to the prognostic value of optimum extent of lymphadenectomy, total number of nodes removed, LN ratio (LNR) and neutrophil-lymphocyte ratio (NLR) on overall survival (OS) and disease-free survival (DFS) following PHCCA resection. METHODS: From 1994 to 2010, 84 PHCCAs were resected; 78 are included in this analysis. Kaplan-Meier survival curves were studied using log-rank statistics to assess which variables affected OS and DFS. The variables that showed statistical significance (P<0.05) on Kaplan-Meier univariate analysis were subjected to multivariate analysis using Cox proportional hazards model. RESULTS: Five-year OS for node-positive status (n=45) was 10%, whereas node-negative (n=33) OS was 41% (P<0.001). Similarly, 5-year DFS was worse in the node-positive group (8%) than in the node-negative group (36%, P=0.001). There was no difference in 5-year OS (31 vs. 12%, P=0.135) and DFS (22 vs. 16%, P=0.518) between those with regional lymphadenectomy and those who underwent regional plus para-aortic lymphadenectomy, respectively. On univariate analysis, patients with 20 or more LNs removed had worse 5-year OS (0%) when compared with those with less than 20 LNs removed (29%, P=0.047). Moderate/poor tumour differentiation, distant metastasis and LN involvement were independent predictors of OS. Positive LNR had no effect on OS. Vascular invasion and an LNR of at least 0.37 were independent predictors of DFS. NLR had no effect on OS and DFS. CONCLUSION: Extended lymphadenectomy patients (≥20 LNs) had worse OS when compared with those with more limited (<20 LNs) resection. An LNR of at least 0.37 is an independent predictor of DFS.

Cardiac surgical theatre traffic: time for traffic calming measures?

Surgical site infections (SSIs) remain a significant cause of postoperative complications. The risk of death from a medical error in a UK hospital remains one in 300. Increased theatre traffic has been identified as a modifiable determinant of SSI and surgical error. This cross-sectional study for the first time describes the pattern of theatre traffic in a UK cardiac centre. An electronic door counter and galaxy theatre management software (v3.4, iSOFT Banbury, UK) were used to calculate frequencies and rates of door opening during operations. Forty-six cases were analysed with 4273 door openings recorded. The median age of patients was 65 (range 43-75) with a median EuroSCORE of 5 (1-14). The mean frequency of door openings per case was 92.9 (45-205), with 19.2 (6.4-38.2) openings per hour. The theatre door was open for 10.7% of each hour of operating. Prolonged, acute and cases involving patients with higher EuroSCOREs demonstrated a trend towards increased opening. Door opening disturbs theatre airflow and results in increased air and wound contamination. It is also described as a contributor to surgical mistakes. Current levels of traffic are unacceptably high and represent a modifiable risk factor for SSI and error.

Coronary artery aneurysms.

Aneurysmal coronary artery disease is frequently encountered in clinical cardiology practice. Although more commonly associated with atherosclerosis, a variety of other acquired (eg, inflammatory, infectious, iatrogenic) or congenital causes have been identified. Recent research on the pathogenesis of coronary aneurysms has yielded interesting results. Advances in imaging have also provided new insights as to the nature of angiographic coronary aneurysms. Critical assessment of the abnormal flow dynamics and pathophysiology of aneurysms has been performed and there is an improved understanding of the associated complications. We present an extensive review of the recent literature highlighting the major advances in the field.

Traumatic partial avulsion of a single right subclavian artery from the aortic arch and definitive repair.

Blunt injury to the right subclavian artery is a rare complication of severe deceleration trauma often associated with significant morbidity and mortality. We describe an atypical presentation in a patient who sustained a traumatic avulsion of his right subclavian artery arising off the aortic arch. An interposition graft was used to restore the continuity of the artery to the ascending thoracic aorta.